Workshop on Supercritical Fluids and Energy

workshop on supercritical fl uids and energy ESTA OBRA FOI IMPRESSA EM PAPEL RECICLATO 75% PRÉ-CONSUMO, 25 % PÓS-CONSUMO, A PARTIR DE IMPRESSÕES E TIRAGENS SUSTENTÁVEIS. CUMPRIMOS NOSSO PAPEL NA EDUCAÇÃO E NA PRESERVAÇÃO DO MEIO AMBIENTE. workshop on supercritical fl uids and energy Dados Internacionais de Catalogação na Publicação (CIP) (Câmara Brasileira do Livro, SP, Brasil) Workshop em fluídos supercríticos e energia / M. Angela A. Meireles e Erdogan Kiran. (organizadores). – Campinas, SP : Mercado de Letras, 2013. – (Mercado de Letras Temas)

ISBN 978-85-7591-301-7

1. Biocombustíveis 2. Energia – Fontes alternativas 3. Fluídos supercríticos I. Meireles, M. Angela A. II. Kiran, Erdogan III. Série.

13-12026 CDD-541.34 Índices para catálogo sistemático: 1. Fluídos supercríticos e energia 541.34

Capa e Projeto Gráfico: Vande Rotta Gomide Layout e Editoração: André S. Tavares da Silva Revisão: Gabriela Lopes Adami

DIREITOS RESERVADOS PARA A LÍNGUA INGLESA: © MERCADO DE LETRAS EDIÇÕES E LIVRARIA LTDA. Rua João da Cruz e Souza, 53 Telefax: (19) 3241-7514 – CEP 13070-116 Campinas SP Brasil www.mercado-de-letras.com.br [email protected]

1a edição dezembro/2013 IMPRESSÃO DIGITAL IMPRESSO NO BRASIL

Esta obra está protegida pela Lei 9610/98. É proibida sua reprodução parcial ou total sem a autorização prévia do Editor. O infrator estará sujeito às penalidades previstas na Lei. Contents

Preface...... 7 Presentation ...... 13 Goals ...... 15 Committee ...... 17

Overview/Plenary Lectures on the Role of Supercritical Fluids and Technology (SCFs&T) State of SCFs&T — Future Directions and Progress in Commercialization...... 19 SCFs&T for Bio-based Fuel processes ...... 39 SCFs&T for New Materials and Materials Processing...... 49 SCFs&T for Green Chemistry and Sustainable Technology ...... 69 SCFs as Working Fluids and Process Technology. . 83

Panel Presentations Panel I: Bio-based fuel processes...... 103 Panel II: New Materials and Materials Processing...... 129 Panel III: Green Chemistry and Sustainable Technology ...... 159 Panel IV: SCFs as Working Fluids / Process Technology and Design...... 187 Panel V: Process Technology and Future Direction...... 215

Posters...... 243

Index...... 387

PREFACE

It is with pleasure that we present this book of abstracts of the lectures and posters that will be presented at the Workshop on Supercritical Fluids and Energy. The idea of organizing a workshop on supercritical fluids with a focus on energy emerged during the course of casual exchanges between the co-directors of this workshop who shared the same dinner table at the Gala Dinner at the 10th International Symposium on Supercritical Flu- ids held in San Francisco in May 2012. The discussions had initially started with commentaries on the ongoing symposium and on the current status and future directions of the supercritical fluid science and technology. One of the questions that immediately surfaced was “how come no industrial plants that employ supercritical fluids had been built in Brazil or in South America despite decades of ongoing active research by many in the region?” The discussion quickly expanded and the questions became broader. Brazil having played such an important role in bio-ethanol production, and there being an ever increasing interest in alternative fuels around the world, we questioned how new opportunities could be developed for the supercritical fluid-based technologies to make an impact in Brazil and elsewhere. What were the limitations? Where were the bottlenecks? What was missing on fundamental data? Were there misconceptions, if any, that needed to be overcome to raise the level of interest for industrial implementation? Were there a critical mass of trained en-

 7 8  SFE 2013 | workshop on supercritical fluids and energy gineers who could take charge of such facilities and run them safely if they were to be built? Furthermore, since supercritical fluid research could impact “energy” use or savings in many other ways than just developing new approaches to generate alternative fuels, additional questions were raised on the impact of using supercritical fluids as working fluids in power cycles; the energy saving potential in materials processing, or forming new materials ranging from particles, to fibers, to foams and aerogels with supercritical fluids. It immediately became clear that addressing these questions would greatly benefit our greater community. When viewed under such a broad umbrella, the appeal of a Workshop, rather than a traditional conference or symposia became extremely high as it would then be attractive to colleagues with different backgrounds; with everyone easily contributing by sharing their perspectives of what is known, what is needed, and where the future trends in the field lie from their own strength areas, while gaining new perspectives in others. With this background, we started to seek funding for the Workshop. The goal was to generate sufficient funds to facilitate participation not only by experts but also by young scientists. The Journal of Supercritical Fluids made an early commitment to support the idea as the timing of the workshop would nicely coincide with and mark the 25th anniversary of the Journal being in publication. LASEFI was also immediately on board. One of us (E. Kiran) discussed the idea with the program managers for “Environmental Sustainability” and “Energy and Sustainability” at the National Science Foun- dation at the 2012 AIChE Annual Meeting in Pittsburg in November 2012, and then submitted a proposal to NSF which was funded. Simultaneously, a similar project was submitted (by M.A.A. Meireles) to CNPq (Conselho Nacio- PREFACE  9 nal de Desenvolvimento Científico e Tecnológico/ Nation- al Council for Scientific and Technological Development) in Brazil which was also funded. With a sound base-funding secured from NSF, LASEFI, CNPq and the Journal of Supercritical Fluids, the workshop was formally announced at the 3rd Iberoamer- ican Conference on Supercritical Fluids that was held in Cartagena, Colombia in April 2013. Our initial plans were to organize a modest workshop with a total of about 50-60 participants consisting of 25-30 experts and 25-35 postdoctoral fellows or senior graduate students. However, the interest in the workshop far exceeded our initial expectations. We are extremely pleased that we have a total of 104 participants from 20 different countries. The first day of the technical sessions of the workshop is devoted to a total of 21 overview/plenary lectures that are grouped under

1. State of the supercritical fluid science and technology — future direction and status of commercialization,

2. Supercritical fluid science and technology for biobased fuel processes,

3. Supercritical fluid science and technology for new materials and materials processing,

4. Supercritical fluid science and technology for green chemistry and sustainable technology and

5. Supercritical fluids as working fluids and process technology.

The second day of technical sessions is devoted to 37 lectures on the role of supercritical fluid science and 10  SFE 2013 | workshop on supercritical fluids and energy technology that will be presented and discussed in five parallel-run Panel sessions grouped under:

1. Bio-base fuel processes

2. New materials and materials processing

3. Green chemistry and sustainable technology

4. Supercritical fluids as working fluids / process technology and design

5. Process technology and future directions.

Also scheduled for the second day of the workshop is the afternoon Poster Session that will have 42 presentations by junior faculty members, postdoctoral fellows, research associates, or senior graduate students. The third day of the workshop is devoted to the presentations and the discussions of the panel outcomes by all participants. This book of abstracts includes all the abstracts of the overview and the panel lectures and the poster presentations which we trust you will find of value as a future reference. We would like to take this opportunity to thank all the participants for their willingness to come to this workshop and share their knowledge, and their commitment to the advancement of our field. We are optimistic that this workshop will lead to new interactions and collabo- rations, and in particular will help the next generation of scientists to be connected with our greater community. We are grateful to our international and local organizing committee members, Drs. Gerd Brunner, Richard Smith, Flávio C. Albuquerque, Sandra R. S. Ferreira, Camila G. Pereira, Hosiberto B. Sant’Ana and Diego T. Santos for their valuable insight in organization and help with the logistics. PREFACE  11

We would also like to thank the various government and private organizations which have provided additional financial support to make this workshop possible. Our special thanks go to Drs. Bruce Hamilton and Ram Gupta of the National Science Foundation, CNPq, CAPES-PROEX, Dr. Angela Welch of Elsevier and the Journal of Supercrit- ical Fluids, Dr. J. W. King of the Supercritical Fluid Sym- posia, Dr. Jacques Fages of the International Society for Advancement of Supercritical Fluids, Volkmar Steinhagen of UHDE, Chris Spilsbury of the BG Group, and Kenneth R. Krewson of Supercritical Fluid Technologies.

M. Angela A. Meireles Erdogan Kiran Workshop Directors

PRESENTATION

Supercritical fluids are a unique class of process fluids and solvents, which display tunable properties. They are employed at conditions beyond the thermodynamic vapor- liquid critical point. At those conditions, properties of supercritical fluids can be changed over a wide range, and adapted to process needs. They are attractive process fluids in combining a set of unique properties like low viscosity, high diffusivity, zero surface tension, and a high compressibility. Water, for example, is used extensively as working fluid in power generation processes, at conditions below the critical point and increasingly at supercritical conditions. Carbon dioxide and ammonia are utilized in a similar way. Supercritical fluids modify the properties of compounds in mixtures. They dissolve components far beyond their vapor pressure. They dissolve in other fluids and solids, reducing their viscosity and surface tension substantially. In chemical reactions, supercritical fluids act as non- reac- tive process fluid or take part in the reaction, as is the case with water in hydrolysis of biomass components or in oxidative waste destruction. In materials processing, supercritical fluids become effective in modulating miscibility and phase separation conditions leading to formation of materials with a range of different morphologies. The practical application of supercritical fluids requires understanding of the fundamentals of multiphase equilibria at high pressures and ultimately the design of

 13 14  SFE 2013 | workshop on supercritical fluids and energy technical components and plants for production. Compared to other technical systems, supercritical fluid production plants are relatively simple, but the underlying principles are complex and must be thoroughly investigated and transferred to the users. Significant advances have been made over the past three decades in understanding the interaction of supercritical fluids with natural and synthetic materials for physical and chemical transformations with beneficial results that offer new and alternative pathways to materials processing. Advances have also been made in the engineering of processes, which employ supercritical fluids as process media. One area of special importance that has emerged is “Energy” in terms of the (a) use of supercritical fluids in power generation or refrigeration; (b) use of supercritical fluids in biomass conversions for biofuel generations; (c) use of supercritical fluids in reducing the environmental footprint of conventional processes; (d) use of supercritical fluids in generating new materials that have improved thermal insulation properties; or (e) use of supercritical fluids or supercritical-fluid based materials in improved separation or property upgrading operations. A current bottleneck is in overcoming some of the misconceptions pertaining to overall costs and economics of the potential processes in transforming the technology base to large-scale implantations. It is with this background that the proposed workshop is being organized. The workshop will be held in Brazil, which is leading in its activity in bio-based alternative fuels and as such is a natural location to address the central topic of Energy. Brazil is also a location where intense activity is taking place in bio-based material processing and will provide a platform to look at the limitations in going from bench top research to industrial implementation. GOALS

The primary objective of this workshop is to create an opportunity to (a) critically review the state of supercritical fluid science and technology and its impact in various facets of energy generation or energy savings and reveal new perspectives for the improvement of energy related processes, (b) assess the bottlenecks that are preventing industrial scale implementation, (c) develop recommenda- tions to facilitate transformation of lab scale findings to large scale operations, and in so doing (d) identify future research needs and mechanisms to rejuvenate and strength- en interest and continuing support from federal agencies for fundamental research to promote further developments. The SFE’13 also intends to engage up and coming new leaders in supercritical fluid science and technology by bringing them to this workshop, and having them fully integrated into the broader network and give them a stronger base to move forward. In 1993 and 1998 two NATO Advanced Study Institutes had been organized each of which had brought together about 25 lecturers and 75 young scientists. Those young scientists have themselves now become leading names around the world with very effective networking. It is anticipated that this workshop will have a similar impact. Even though smaller in scale, the workshop will be addressing an extremely significant focus area and we believe will have a major impact. We anticipate that the workshop will form a nucleus for new collaborative efforts and possible multi-national research initiatives.

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COMMITTEE

WORKShOP DIRECTORS M. Angela A. Meireles, University of Campinas, Brazil – Founder of Laboratory of Supercritical Technology: Extraction, Fractionation, and Identiﬁ cation of vegetable extracts (LASEFI); [email protected] Erdogan Kiran, Virginia Polytechnic Institute and State University, USA – Founder and Editor-in-Chief of the Journal of Supercritical Fluids; [email protected]

INTERNATIONAL SCIENTIFIC COMMITTEE Gerd Brunner, Hamburg University of Technology, Germany – Regional Editor (Europe) of the Journal of Supercritical Fluids M. Angela A. Meireles, University of Campinas, Brazil Erdogan Kiran, Virginia Polytechnic Institute and State University, USA Richard Smith Jr., Tohoku University, Japan – Regional Editor (Asia) of the Journal of Supercritical Fluids

LOCAL ORGANIzING COMMITTEE Flávio C. Albuquerque, PETROBRAS Research & Development Center, Brazil Sandra R. S. Ferreira, Federal University of Santa Catarina, Brazil Camila G. Pereira, Federal University of Rio Grande do Norte, Brazil Hosiberto B. Sant’Ana, Federal University of Ceara, Brazil Diego T. Santos, University of Campinas, Brazil

 17

OVERVIEW/ PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)

State of SCFs&T — Future Directions and Progress in Commercialization Process Technology and Future Directions PROCESS TEChNOLOGy AND FUTURE DIRECTIONS

gerd Brunner Hamburg University of Technology; Eissendorfer Str. 38, D-21073, Hamburg, Germany; E-mail: [email protected] what is “Process Technology”? Process technology comprises the application of fundamentals to processes, as for example phase equilibria and reaction kinetics, the verification of process steps, as for example in specific reactors, and the design of process sequences to produce a product (energy!) from raw materials. For the special field of Supercritical Fluids related to energy processes this general definition also applies. Self-evident as this is, it includes single process steps as well as process step sequences and whole processes. Also, process technology is not restricted to any specific application. It includes processing of renewable (bio-based) materials, fossil materials, and processes to access these materials. In general, process technology related to the application of supercritical fluids is based on the exploitation of the specific properties of supercritical fluids. Again, self-evident as it is, it includes the varying properties of supercritical fluids itself and hence the tunability of the working fluid and the interactions of supercritical fluids with the processes materials. Mostly we have in mind in this context the change of properties by dissolved supercritical fluids, for example a drastically reduced viscosity.

 21 22  SFE 2013 | workshop on supercritical fluids and energy

Furthermore, supercritical fluids guarantee an enclosed processing with emanations that can be adjusted. Super- critical fluid processing of most materials results in a reduced amount of gas production. That gas can still be used to fuel the process. In addition, supercritical fluids can lead to improved yields, as I will show in an example for oil shale exploitation, and in improved quality of the products. Supercritical fluids have been used in quite a number of processes and process steps related to production of energy, mostly in laboratory and demonstration scale. Among these processes are: The ROSE process, coal liquefaction and gasification, the production of oil from oil shales, and of oil from oil sands. Supercritical fluids have been proposed (and partially are used) for: enhanced oil recovery, emulsion splitting (oil-water), enhanced gas recovery, bitumen separation, recovery of hydrocarbons from particles (remediation of soil), de-asphalting, removal of fine particles, and others. Supercritical fluids are proposed for deep drilling (spall- ation drilling), and for the production of energy from hydrothermal flames. Process technology has to provide the equipment for the processes. In general, there is no principal differ- ence for bio-based materials and non-bio-based materials. Design according to the process fundamentals has to be provided for: reactors, heat transfer equipment, heat recovery systems, and systems for delivery and recovery of solids. In addition, the question of corrosion has to be an- swered. Future directions can be seen in the provision of fundamentals: for oil/water/SCF-processes, for oil/water/ SCF/particles-processes, for the design of small scale installations (economy, standardization), and for the design State of SCFs&T | Future Directions and Progress in Commercialization  23

of proper technology for feeding and removal of solids. Keys to future success will be: simple design, simple operation, high efficiency (higher than burning the feed), and a thorough training of the community in the specific abilities of supercritical fluids. Challenges and opportunities using supercritical CO2: from fundamentals to industrial applications ChALLENGES AND OPPORTUNITIES

USING SUPERCRITICAL CO2: FROM FUNDAMENTALS TO INDUSTRIAL APPLICATIONS

Lourdes f. vega MATGAS Research Center / AIr Products Group; MATGAS Building – Campus UAB, 08193, Bellaterra, Barcelona, Spain; E-mail: [email protected]

As defined by the Brundtland Commission, sustainable development is the development that “meets the needs of the present without compromising the ability of future generations to meet their own needs”. Sustainable development is of special relevance in the present situation, in which an explosive growth in energy consumption as a consequence of the great inventions and developments related to transportation, computers and technology is observed, along with a rapid increase in population worldwide. In this context, a great effort has been devoted in recent years to develop sustainable processes or improving existing ones, searching for a net positive impact in the environment.

Carbon dioxide (CO2) is finding more and more uses in industry today, from food and water treatment to energy and materials, replacing in some cases other compounds with more impact into the environment. Among these applications, supercritical carbon dioxide (scCO2) is used as an alternative attractive solvent, replacing traditional ones, including hazardous chemicals and precious water resources. scCO2 offers several advantages versus other solvents: it can be easily recycled, it leaves no residues behind after processing and it is non-flammable, non-toxic and inexpensive. The low process temperature

 25 26  SFE 2013 | workshop on supercritical fluids and energy

(31 ºC) allows for gentle processing, while the low surface tension of scCO2 and its high diffusivity allows for excep- tionally effective penetration. Increased environmental awareness had led to restrictions on some traditional solvents which are now recognized as toxic. Only a few sustainable solvents remain available for future use. Hence, as the society and industry continue to demand more efficient and greener processes, CO2 remains an attractive alternative.

There are three key issues driving CO2 applications from labs to industry: the increased fundamental knowledge of CO2 and its interaction with the materials and other compounds, used to find the best process and operating conditions, the optimization of process equipment to handle the demands of operation at an industrial scale, and the need to use environmentally benign solvents and greener processes. In this context, and thanks to the success of adequate modeling tools, accurate experimental measurements and the optimization of the equipments at industrial scale, the use of scCO2 has transitioned, over the past twenty-five years, from a laboratory-based research to a commercial reality, with applications in high-value products such as in pharmaceuticals, nutraceuticals, foods and flavors, polymers and chemicals, as well as in bulk commodity products such as textiles, biofuels and cement. After a general overview, we will address some of the recent applications of CO2 in which our team has been involved, including the recovery of solutes from ionic liquids with CO2 or separation of ionic liquids from organic solvents by CO2 [1,2], the preparation of organic-inorganic materials by scCO2 for CO2 capture and other applications

[3-5], the use of scCO2 to extract high added value products and the scCO2 role in the biofuel arena. Modeling and advanced experimental techniques, from small reactors to State of SCFs&T | Future Directions and Progress in Commercialization  27

pilot plants have been used in order to move the technology forward.

This work is part of a CENIT project SOST-CO2 belonging to the Ingenio 2010 program financed by CDTI, Science and Innovation Department, Spanish Government,

aiming at reducing the emissions of CO2 in Spain and de-

veloping new industrial and sustainable uses of CO2. The project is lead by the company Carburos Metálicos, from Air Products Group, and it comprises 14 other companies and 31 research institutions. Support for this work from Air Products and the Spanish Government through project

CEN-2008-1027 (CENIT SOST-CO2) is gratefully acknowledged. Additional support was provided by the Spanish Government (CTQ2008-05370/PPQ, CTQ2011-23255) and by the Catalan Government (2009SGR-666). The work presented here has been done in collaboration with F. Llovell, S. Builes, O. Vilaseca, R.M. Marcos, R. Solanas, J. Torres, P. López-Aranguren and C. Domingo. Their contributions and continuous support is very much appreciated.

References [1] F. Llovell, O. Vilaseca, L. F. Vega, Thermodynamic modeling of imidaz- olium-based Ionic Liquids with the [PF6] anion by means of the soft- SAFT EoS, Separation Science & Technology, 47 (2011) 399-410. [2] F. Llovell, E. Valente, O. Vilaseca, L. F. Vega, Modeling complex associating mixtures with [Cn-mim][Tf2N] ionic liquids: predictions from the soft-SAFT equation, J. Physical Chemistry B., 115 (2011) 4387-4398. [3] P. López-Aranguren, J. Saurina, L. F. Vega, C. Domingo, Sorption of try-

alkoxysilane in low-cost porous silicates using a supercritical CO2 method, Microporous and Mesoporous Materials, 148 (2012) 15-24. [4] S. Builes, L. F. Vega, Effect of Immobilized Amines on the Sorption Properties of Solid Materials: Impregnation versus Grafting, Langmuir, 9 (2013) 199-206. [5] S. Builes, P. López-Aranguren, J. Fraile, L. F. Vega, C. Domingo, Alkylsilane- Functionalized Microporous and Mesoporous Materials: Molecular Simulation and Experimental Analysis of Gas Adsorption, J. Physical Chemistry C, 116 (2012) 10150-10161. Commercialization of Supercritical Fluid Processes and Products — A Perspective COMMERCIALIzATION OF SUPERCRITICAL FLUID PROCESSES AND PRODUCTS — A PERSPECTIVE

Jerry W. King CFS – University of Arkansas; 1965 E. Spinel Link #7; 72701, Fayetteville, AR, USA; E-mail: [email protected]

Commercializing processes and products that involve pressurized fluids technology has been on-going for over four decades. This presentation is focused on the current status of processes and products contrasted with and future trends/needs as well as application areas. The success of applying a pressurized or supercritical fluid for processing lies in producing a product derived by either extraction-fractionation-reaction methods that is cost competitive with existing products, or fulfills a need where the end user is willing to pay a premium for the benefits derived from the “supercritical” product. This can be challenge in emerging economies such as representing by the BRIC (Brazil-Russia - -India-China) countries as typified by consumer attitudes toward particular products, such as EPA and omega-3 fatty acid nutraceutical supplements. It is interesting to examine platforms, not only in terms of integration of pressurized processing options including critical fluids, but also where the energy versus higher value product use of a renewable substrate perhaps are in competition with one another. For example, consider the case of oils used for either renewable biodiesel versus processing them with scCO2 to extract higher-value nutraceutical ingredients. This competition is particularly acute when the renewable oil source is from algae where

 29 30  SFE 2013 | workshop on supercritical fluids and energy the oil can be converted to biodiesel via several routes which can use supercritical media (scCO2, supercritical methanol, etc.), or be processed using scCO2 for its omega fatty acid content (market potential: 2011 — $25.4 billion; 2016 — $34.7 billion — 6.4% rate increase compounded annually), or antioxidant content such as astaxanthin (~$10,000/kg). Several case examples will be provided where a common feed stock such as algae can be fractionated to produce a multiple product portfolio having diversified economic benefit.

Today SFE is driven by the scCO2 processing of nutraceutical/functional food ingredients. Newer SFE “ultra- high” pressure processing plants are now operational and employ extraction pressures up to and beyond 1000 bar. Such conditions permit the co-extraction of synergistic components, i.e., both non-polar and polar compounds which can be rationalized based on their solubility parameters relative to that exhibited by scCO2 at higher pressures and temperatures. It is more difficult to discern commercial products realized by using columnar fractionation or SFC that are being produced on a commercial scale despite considerable research in these areas. Likewise promising reaction chemistries conducted in the presence of supercritical fluids, such as enzyme-based conversions, hydrogenation, etc. have yet to produce commercially-viable products. The use of pressurized water, both in its sub- and super-critical fluid state has been undertaken now for over three decades. The use of pressurized water ranges over a considerable temperature range augmented by appropriate pressures based on its phase diagram. These range from very low pressure conditions for subcritical water extraction (SWE) to higher pressures/temperatures applied in treating renewable energy feed stocks for both chemical State of SCFs&T | Future Directions and Progress in Commercialization  31

and fuel utilization. SWE has received much attention due to the many studies conducted on agriculturally-based renewable materials, and the promise that it can replace organic solvent-based processes — hydroethanolic extrac tion. The future development of this processing technique is very dependent, as most of the high temperature biomass processing technologies on the development of a continuous solids feeding system compatible of operating at higher temperatures and variable pressures. Our studies at the University of Arkansas with modified expeller or auger delivery systems have shown modest success when applied for processing anti-oxidant botanical extracts. The compatibility and cost of such systems can be reduced by applying conventional 316 SS alloys up to the critical point of water, beyond which biomass reforming, pyrolysis, and gasification require more expensive equipment. Perhaps the ultimate criterion of the worth of R & D using high pressure fluids is whether a long term commercial product is realized as the end goal. Examples of successful product platforms have been reviewed by author in the past — the question is what does the future hold? As noted above, developments in SFE are driven by high-value extracts containing ingredients that can provide flavor, antioxidant, or desirable physical properties due to their multi-component composition. Examples of such extracts occur from applying SFE to algae and certain marine-derived products such as krill oil, where the synergistic benefit of extracts containing omega-fatty acids, naturally-derived pigments, and phospholipids have been verified in clinical studies. The extension of these extracts as medicines will require that SFE and related processes be conducted under GMP (Good Manufacturing Practice) conditions, which is different from the criteria applicable 32  SFE 2013 | workshop on supercritical fluids and energy under GLP and GRAS regulations. To date in the development of SCF-based processes, GMP conditions are not always adhered to, but some GMP protocols have been recorded in the preparing particles for the pharmaceutical industry using various pressurized fluids, and similarly in the use of SFC. Despite industrial interest in sub-critical water extracts, such products are difficult to verify in the marketplace. The promise of chemicals and extractives produced by high pressure aqueous processing has often been reported, but downstream purification of these complex extracts and the separation of these components from aqueous media remains a problem due to the additional unit processing costs. In addition, sometimes conversion of these extracted solutes by reaction chemistry is required. Two examples relevant to the above problems will be cited — the extraction of natural polyphenolic antioxidants using SWE or CO2-based extraction, and obtaining the cosmetic ingredient, squalane, from sugar cane biomass. Such extracts are now finding an increased use in the personal care industry and pertinent products will be shown. The consumer is becoming increasingly aware of what differentiates a supercritical fluid-derived product from those obtained via conventional or alternative routes. Ex- amples will be shown of “embracing” the supercritical fluid logo in product advertising as well as benefits that accrue from using a supercritical fluid process, such as the problem with solvent residuals in products. The latter problem beckons for a “supercritical fluid solution”, due to more stringent legislation that is being applied on products intended for health food industry, cosmetic applications, and for medical use. Such products include both extracts and raffinates — saleable products left over after critical fluid processing. Several examples of the latter will be noted from the oilseed medicinal area and marine/ State of SCFs&T | Future Directions and Progress in Commercialization  33

algal-derived products. While economic analysis of production costs in the case of supercritical fluid-based processing is important, it is not the only factor which determines the success of commercial product. Derived products/processes which appeal to the altruistic sensibilities of the end consumer make critical fluid-based processing attractive. The utilization of “green” processing when coupled with a bio-renewable/sustainable production platform can be used advantageously in the marketing of end products

— particularly when they involve the utilization of CO2. Many model or hypothetical bio-refineries with integrated processing utilizing critical fluids have been envisioned, but to date only discrete unit processes have been studied in detail. Adoption of supercritical fluid-based technologies commercially can be greatly aided by utilizing “mobile” plants that allow demonstration of the merits of the technology within existing production facilities.

SUPERCRITICAL FLUIDS IN ENERGy AND BIOFUEL APPLICATIONS

Richard L. smith Jr. Tohoku University; Aoba-ku, Aramaki Aza Aoba 6-6-11, Sendai, Miyagi-ken, 980-8579, Japan; E-mail: [email protected]

Supercritical fluids have application in energy and biofuel processes in their use as (a) working fluids, (b) reaction solvents, (c) mass transfer promoters, (d) heat transfer promoters and (e) separation agents. This work introduces applications of supercritical fluids that demonstrate some of their unique technological advantages and presents aspects of a proposal that uses supercritical CO2 with hydrogen and ionic liquids for the conversion of biomass to biofuels. Supercritical fluids are being used as working fluids in next-generation systems for refrigeration [1], hot-water heating [2], heat-pump [3], natural gas [4-6], geothermal [7], ultrasupercritical boiler [8] applications. In these applications, the homogeneous phase conditions of the transcritical state change gives highly-efficient energy transport. Supercritical fluids can be used as reaction solvents in next-generation chemical processes for producing biodiesel fuel from oilseed crops [9-14]. There are a number of proposals for using supercritical fluids such as methanol [12], combinations with acetic acid [14], methyl acetate [13], and dimethylcarbonate [10], each with its distinctive advance according to the use of raw materials and chemical products and by-products. Use of supercritical methyl acetate as reaction solvent for triglycerides

 35 36  SFE 2013 | workshop on supercritical fluids and energy gives triacetin and avoids the formation of glycerol [9]. Use of supercritical dimethyl carbonate gives glycerol carbonate as a value-added by-product [10]. In this strategy, the solvent is a supercritical fluid that acts not only as a solvent but also as a reactant and promotes heat and mass transfer. In hydrothermal methods, water, which is sometimes combined with additives, is used to pretreat or convert biomass into feedstocks suitable for biofuel production [15-18]. In this strategy, the self-ionization of water is exploited to promote hydrolytic reactions and cellulose depolymerization. Ionic liquids, which are organic salts that are commonly liquid at room temperature, offer an interesting possibility to transform biomass into biofuels [19]. The ionic liquid can act not only as a solvent for biomass, but also as a homogeneous catalyst for transforming biomass substrates into biofuels [19]. In this strategy, an ionic liquid is used as solvent for biomass, cellulose, or a carbohydrate substrate. Many approaches have been taken in the literature. In Qi et al. [20], cellulose is converted into 5-hydroxymethylfurfural in high yields via a two-step process that involves water addition to the reacting mixture. In these systems, as biomass or its related constituents are dissolved into an ionic liquid, the viscosity of the solution greatly increases thus causing the mass transfer to become greatly limited. When the viscosity is reduced by addition of organic solvents or a soluble gas, such as supercritical CO2, many reactions can proceed smoothly [21]. A proposal that we are examining in this work is the transformation of biomass into fuels via catalytic methods [22]. In Chen et al. [22], sugars and polyols undergo direct conversion into n-hexane and n-pentane via catalyst in a triphasic (water-n-dodecane-hydrogen) system. For glucose the reaction is: State of SCFs&T | Future Directions and Progress in Commercialization  37

C6H12O6 + 7H2 -> C6H14 + 6 H2O (1)

Although the method and catalyst give outstanding results (99.9% conversion, 94+% yield), long reaction times (84 h) are required due to mass transfer limitations of both reactants and products. In this work, we consider the use

of supercritical CO2 in the objective for improving the reaction efficiency of Eq. (1) and the use of ionic liquids to expand the application of the catalytic system.

References [1] Y. T. Ge, S. A. Tassou, I. N. Suamir, Prediction and analysis of the sea-

sonal performance of tri-generation and CO2 refrigeration systems in supermarkets, Applied Energy, 112 (2013) 898-906. [2] S. G. Kim, Y. J. Kim, G. Lee, M. S. Kim, The performance of a transcrit-

ical CO2 cycle with an internal heat exchanger for hot water heating, International J. Refrigeration, 28 (2005) 1064-1072.

[3] J. Stene, Residential CO2 heat pump system for combined space heating and hot water heating, International J. Refrigeration, 28 (2005) 1259-1265. [4] W. Lin, N. Zhang, A. Gu, LNG (liquefied natural gas): A necessary part in China’s future energy infrastructure, Energy, 35 (2010) 4383-4391. [5] E. Querol, B. Gonzalez-Regueral, J. García-Torrent, A. Ramos, Available power generation cycles to be coupled with the liquid natural gas (LNG) vaporization process in a Spanish LNG terminal, Applied Energy, 88 (2011) 2382-2390. [6] Y. Song, J. Wang, Y. Dai, E. Zhou, Thermodynamic analysis of a tran-

scritical CO2 power cycle driven by solar energy with liquified natural gas as its heat sink, Applied Energy, 92 (2012) 194-203. [7] X. L. Gu, H. Sato, Performance of supercritical cycles for geothermal binary design, Energy Conversion and Management, 43 (2002) 961-971. [8] S. Kaneko, K. Yamamoto, M. Kinoshita, Y. Wakabayashi, Y. Iida, Design and operation experience of a 1000 MW ultra supercritical coal fired boiler with steam condition of 25.4 MPa 604/602 °C, Technical Review — Mitsubishi Heavy Industries, 36 (1999) 61-65. [9] F. Goembira, S. Saka, Optimization of biodiesel production by supercritical methyl acetate, Bioresource Technology, 131 (2013) 47-52. [10] Z. Ilham, S. Saka, Optimization of supercritical dimethyl carbonate method for biodiesel production, Fuel, 97 (2012) 670-677. 38  SFE 2013 | workshop on supercritical fluids and energy

[11] J. S. Lee, S. Saka, Biodiesel production by heterogeneous catalysts and supercritical technologies, Bioresource Technology, 101 (2010) 7191-7200. [12] E. Minami, S. Saka, Kinetics of hydrolysis and methyl esterification for biodiesel production in two-step supercritical methanol process, Fuel, 85 (2006) 2479-2483. [13] S. Saka, Y. Isayama, A new process for catalyst-free production of biodiesel using supercritical methyl acetate, Fuel, 88 (2009) 1307-1313. [14] S. Saka, Y. Isayama, Z. Ilham, X. Jiayu, New process for catalyst-free biodiesel production using subcritical acetic acid and supercritical methanol, Fuel, 89 (2010) 1442-1446. [15] R. Feiner, N. Schwaiger, H. Pucher, L. Ellmaier, P. Pucher, M. Sieben- hofer, Liquefaction of pyrolysis derived biochar: A new step towards biofuel from renewable resources, RSC Advances, 3 (2013) 17898-17903. [16] M. C. Johnson, J. W. Tester, Lipid transformation in hydrothermal processing of whole algal cells, Industrial and Engineering Chemistry Research, 52 (2013) 10988-10995. [17] Z. Liu, A. Quek, R. Balasubramanian, Preparation and characterization of fuel pellets from woody biomass, agro-residues and their corresponding hydrochars, Applied Energy, 113 (2014) 1315-1322. [18] H. Ramsurn, R. B. Gupta, Deoxy-liquefaction of switchgrass in supercritical water with calcium formate as an in-situ hydrogen donor, Biore- source Technology, 143 (2013) 575-583. [19] Z. Fang, R. L. Smith Jr., X. Qi, Production of biofuels and chemicals with ionic liquids, in: Biofuels and Biorefineries 1; Springer, 2013. [20] X. Qi, M. Watanabe, T. M. Aida, R. L. Smith Jr., Catalytic conversion of cellulose into 5-hydroxymethylfurfural in high yields via a two-step process, Cellulose, 18 (2011) 1327-1333. [21] X. Qi, M. Watanabe, T. M. Aida, R. L. Smith Jr., Efficient catalytic conversion of fructose into 5-hydroxymethylfurfural in ionic liquids at room temperature, ChemSusChem, 2 (2009) 944-946. [22] K. Chen, M. Tamura, Z. Yuan Y. Nakagawa, K. Tomishige, One-pot conversion of sugar and sugar polyols to n-alkanes without C-C dissociation over the Ir-ReOx/SiO2 catalyst combined with H-ZSM-5, ChemSus- Chem, 6 (2013) 613-621. OVERVIEW/ PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)

SCFs&T for Bio-based Fuel processes

wATER — A “MAGIC” TOOL TO CONVERT BIOMASS?

Andrea Kruse University Hohenheim; Garbenstrasse 9, 70599, Stuttgart, BaWü, Germany; E-mail: [email protected]

Fresh biomass could be dried and combusted or gasified by a “dry process”. Such processes are under development and are similar to fossil coal processing. The motivation for such R&D work is the wish to become more independent of the vanishing fossil resources for energy supply and chemically produced products. However, drying is associated with considerable costs at high water content of 80-90% in green plants. On the other hand, most of the up to now unused, and therefore most attractive, biomass has such high water content. For such “wet” or “green” biomass, hydrothermal biomass conversion methods are superior. The expression “hydrothermal” is originally used in geology to name reaction in water at increased temperatures and pressures. Depending on the reaction conditions, different fuels or basic chemicals, to produce e.g. polymers, can be formed. These fuels are a solid, liquid (with a very high viscosity) or gaseous. The selectivity towards these products is usually higher and the temperatures lower than in the analogous dry processes. The reason for the lower temperature is the high reactivity of biomass in water. The reasons for the high selectivity are the lower temperature and the change of water properties with reaction conditions. All hydrothermal biomass conversion processes take benefit of the special properties of

 41 42  SFE 2013 | workshop on supercritical fluids and energy hot compressed liquid or supercritical water. At subcritical conditions, the ionic product of water is higher as at ambient conditions. The reason is the endothermic character of the self-dissociation of water. The high H+ and OH- concentrations enable rather high reaction rates of reactions usually require the presence of acids and bases. In other cases, water itself works as catalyst, fulfilling the role usually done by H+ or OH-. At supercritical conditions (above 374 °C and 22.1 MPa) water behaves like a non-polar solvent but the water molecules are still polar. These unique properties mainly avoid unwanted polymerization by splitting large molecules and solving the products. This hydrothermal biomass conversion processes introduced here are:

I. Pretreatment. At lower temperatures we found different pre-treatment methods, e.g. simply cooking of biomass. The (exothermic) degradation of biomass starts at around 170 °C.

II. Hydrothermal Carbonization. At around 200 °C, there are the operation conditions of hydrothermal carbonization (HTC) of biomass. Here artificial coal is produced with very high yield, often in the presence of an acid as catalyst. From the chemical point of view and at this condition, most of the biomass is split first. The splitting of carbohydrates like cellulose and hemicelluloses is supported by the high ionic product of water. The product, glucose con- verts partially to fructose. If the reaction is stopped at this point the products glucose and fructose can be feed for microorganism. By water elimination, hydroxymethylfurfural (HMF) from fructose is produced. HMF is an important platform chemical which may substitute compounds from fossil oil to SCFs&T for Bio-based Fuel processes  43

produce a wide range of products, e.g. polymers. If the reaction is not stopped at this stage, a solid product is formed by polymerization. This brown or black product has nearly the heating value of fossil lignite. Therefore the process is called “Carbonization”.

III. Aqueous Reforming. At slightly higher temperature hydrogen can be produced from compounds originating from biomass using noble metal catalysts. This process, called aqueous reforming, works because of thermodynamic reason only at very low concentrations and up to now not with real biomass. The hydrogen can be use for in-situ hydrogenation of the feedstock to produce hydrocarbons, if a suitable catalyst is present.

IV. Hydrothermal liquefaction. At around 300 to 350 °C biomass liquefaction occurs. This process developed originally by the company Shell as hydrothermal upgrading, lead to a high viscous product with a lower oxygen content and higher heating valve than the product of dry biomass liquefaction (fast pyrolysis). In some cases (alkali) catalysts are applied and recently the focus is on liquefaction of algae. A special application is the splitting of lignin to phenols which are precursors of resins. In this case temperatures of around 400 °C are useful. Lignin is the only common renewable resource for aromatic compounds, which are produced from fossil oil today.

V. Near critical gasification. Near the critical point the catalyzed hydrothermal gasification is conducted.

Methane and CO2 are the main products and heterogeneous catalysts are necessary. In this temperature range methane is the main burnable product in equilibrium, but noble metal catalysts are necessary because methane formation is kinetically inhibited. 44  SFE 2013 | workshop on supercritical fluids and energy

VI. Supercritical water gasification. This process is called Fundamentals of the supercritical water gasification, because of the re- supercritical water oxidation actions conditions above the critical point of water. process for an efficient and The wished product is hydrogen. Usually tempera- clean energy production tures at or above 600 °C are applied because only at high temperature hydrogen is the preferred product in equilibrium. Catalysts are salts included in the biomass. Heterogeneous, e.g. noble metals as well as carbon catalysts are not necessary but often used to reduce the temperature or to increase the gas yield at higher dry mass content and concentrations, respectively.

Depending on the reaction conditions, a wide range of products like different energy carriers (gaseous, liquid or solid) or platform chemicals are available. This is a consequence of the change in the water properties with temperature and density. The variability of the reaction medium is unique and is the key for the use of “wet” or “green” biomass. Water is a natural ingredient of biomass which becomes the reaction medium by heating-up. This typical property of hydrothermal reactions opens a lot of possibilities e.g. to combine them with biochemical reactions that are also occurring in water. On the first view hydrothermal processes seems to be an important tool for a “bio-refinery” to produce various products by usage of the complete plants. On the other hand there are some challenges. Which challenges are the most important depend on the temperature or wished product. E.g. for hydrothermal carbonization and hydrothermal liquefaction the treatment of the waste water is important. For the processes using heterogeneous catalyst, poising is the largest hurdle to overcome. For supercritical water the strong conditions limits the reactor material lifetime. FUNDAMENTALS OF ThE SUPERCRITICAL wATER OxIDATION PROCESS FOR AN EFFICIENT AND CLEAN ENERGy PRODUCTION

Maria José cocero School of Industrial Engineering, Sede Mergelina Chemical Engineering Department, Valladolid University; 47011, Valladolid, Spain; E-mail: [email protected] high pressurized water (HPW) / Supercritical water (SCW) properties as reaction media. Water offers many favorable properties at elevated temperatures and pressures that make it therefore an excellent solvent and reaction medium for numerous applications. In the vicinity of the critical point the thermodynamic properties of water change drastically compared to those of liquid water [1]. The density (ρ), dielectric constant (ε) and ionic product of water (Kw) from 0 ºC to 600 ºC at a pressure of 25 MPa can be calculated according to the equations developed in literature [2,3]. The change in the dielectric constant is proportional to the density and inversely proportional to the temperature. Hydrogen bonds present a behavior analogous to that of the dielectric constant. Another important property of the organic reaction media is the ionic product of water. Around 300 ºC the value of the ionic product of water reaches its maximum (1.10-11), which creates a medium with high H+ and OH- concentrations, thus favoring in this way acid/basis catalyzed reactions. Above the critical temperature of water (374 ºC), the Kw decreases drastically (1.10-25) [4]. At higher pressures (P>60 MPa) the Kw again presents values similar to those of ambient water. The significant drop in the dielectric strength leads to

 45 46  SFE 2013 | workshop on supercritical fluids and energy a considerable increase in the solubility of hydrocarbons in supercritical water. In correlation, the solubility of inorganic salts reduces drastically. Supercritical water acts like a non-polar dense gas with solvation properties equivalent to those of low polar organic solvents. Additionally the gases as CO2, O2, N2 are completely miscible in SCW [1]. These physical properties are the reason to consider supercritical water as an ideal media for the oxidation of organic compounds. The reaction takes place in a single phase, avoiding interfacial mass transfer resistances. Su- percritical Water Oxidation process. The process known as supercritical water oxidation (SCWO) consists of the homogeneous oxidation of chemical compounds in an aqueous medium using air, oxygen or hydrogen peroxide as oxidizing agent, at temperatures and pressures above the critical point of water (374 ºC and 22.4 MPa). The SCWO takes place in three steps: Feed preparation and pressurization; Reaction and solids separation; and Depressuriza- tion and heat recovery [1]. Technically, the SCWO has the advantage of simple, fast and homogeneous reactions without mass transfer limitations. It also has some limitations related to extreme operating conditions and their effect on the materials equipment. Therefore, the main challenges of SCWO are corrosion and deposition of salts, which are being solved by the use of special construction materials and the development of new reactor designs able to soften the conditions that the materials must resist. SCWO kinetic can be described by a radically reaction mechanic, but when the temperature of the mixture is higher than the auto ignition temperature, supercritical water oxidation proceeds in the form of flames called hydrothermal flames. In general, flames ignited spontaneous- ly beyond a certain temperature, normally between 400 and 500 ºC. This auto ignition temperature was decreased SCFs&T for Bio-based Fuel processes  47 for higher pressures and fuel concentrations [5]. Hydro- thermal flames are combustion flames produced in aqueous environments at conditions above the critical point of water (P>221 bar and T>374 ºC).The flame is defined as the surface where combustion is produced. This surface separates the oxidant from the fuel in the case of diffusion or non-premixed flames, in which fuel is injected into the oxidant. In the case of premixed flames, that is, when the fuel and oxidant are injected already mixed, the flame is the surface separating the reagents from the reaction products. In premixed flames, the surface is moving towards the reagents with a flame front velocity. If this velocity is the same as the fluid velocity the flame will remain still in a fixed position. In general, the conditions of the flame ignition depended on the fuel, the oxidant, and the ratio of fuel/oxidant and the geometry of the injection system. SCWO with a hydrothermal flame has a number of advantages over the flameless process. Some of these advantages permit overcoming the traditional challenges that make the successful and profitable commercialization of SCWO technology difficult [6]:

Allow the destruction of the pollutants in residence times of a few milliseconds: construction of smaller reactors.

Reaction with feed injection temperatures near to room temperature, avoids problems such as plugging and corrosion in a preheating system and advantages from the operational and energy integration perspective.

Higher operation temperatures, improve the energy recovery Energy by supercritical water oxidation. 48  SFE 2013 | workshop on supercritical fluids and energy

The research group has been very active in the developing of SCWO process as an efficient and environmental compatible process for the treatment of wastes [1]. The SCWO process can reduce significantly the operation time by using hydrothermal flames. The results showed that the SCWO technology, using hydrothermal flame, is able to oxidize high amounts of compounds in residence times of around 1s, using very compact reactors and producing

CO2, water, salts and energy [7]. Our last contribution is a new reactor to produce energy. A 650 ºC up-reactor effluent can be combined with a gas turbine to produce work and energy. For example, by using the conventional Rankin cycle to produce 1 MW by SCWO reactor effluent, the pump and air compressor consume 1,64 MW. The new reactor allows the production of 1 MW by consuming 0,78 MW, so this could be a way of producing neat excess energy [8].

References. [1] M. D. Bermejo, M. J. Cocero, AIChE J., 52 (2006) 3933-3951. [2] W. L. Marshall, E. U. Franck, J. Physical and Chemical Reference Data, 10(2) (1981) 295-304. [3] M. Uematsu, E. U. Franck, J. Physical and Chemical Reference Data, 9(4) (1980) 1291-13. [4] N. Akiya, P. E. Savage, Chemical Reviews, 102(8) (2002) 2725-2750. [5] W. Schilling, E. U. Franck, Berichte der Bunsengesell-schaft für physi- kalische chemie, 92 (1988) 631-636. [6] C. Augustine, J. W. Tester, Hydrothermal flames: From phenomeno- logical experimental demonstrations to quantitative understanding, J. Supercritical Fluids, 47 (2009) 415-430. [7] M. D. Bermejo, C. Jiménez, P. Cabeza, A. Matías-Gago, M. J. Cocero, J. Supercritical Fluids, 59 (2011) 140-148. [8] P. Cabeza, M. D. Bermejo, C. Jiménez, M. J. Cocero, Water Research, 45(8) (2011) 2485-2495. OVERVIEW/ PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)

SCFs&T for New Materials and Materials Processing

AEROGELS OF DIFFERENT ORIGINS: A JOURNEy FROM INSULATION MATERIALS TO ADDED-VALUE PRODUCTS OF BIOREFINERy

irina smirnova University of Technology Hamburg-Harburg; Eissendorferstr. 38, 21075, Hamburg, Germany; E-mail: [email protected]

Aerogels are known as a special class of nanoporous materials already since 1930. They are obtained from wet gels by using a suitable drying technology, usually a supercritical drying process, able to avoid the pore collapse phenomenon and keep intact the porous texture of the wet material. Efforts have been traditionally focused on silica aerogel and carbon aerogel development with a wide range of applications in different fields, e.g., aeronautics, bio- medicine, construction, environmental remediation or agriculture. However, among the broad range of possible applications, just few of them have been commercialized so far. Main application is the thermal insulation due to the extremely low thermal conductivity of aerogels. The main issues behind this situation are the production costs, associated with the raw materials and with supercritical fluid extraction needed for the synthesis of aerogels with low density. Regarding the raw materials, in the last decades it was realized, that aerogels may be produced from a great variety of different organic and inorganic materials and are not restricted by traditional matrices like silica or carbon ones. Moreover, a lot of biopolymers, having an advantage of biocompatibility were successfully transferred in an aerogel form. Generally, all materials that can be obtained as wet gels by the sol-gel process are potential

 51 52  SFE 2013 | workshop on supercritical fluids and energy candidates to be turned into aerogels after supercritical drying. New aerogel classes become especially interested as intelligent insulation materials, allowing to reduce the thickness of the insulation significantly. Furthermore, the applications in the pharmaceutical and food areas seem to be promising even in front of higher production costs. Also a combination of the aerogels production with the biorefinery processes can be realized by using of biorefinery products as raw materials for gelation. This was for instance demonstrated by using lignin as a precursor. So far it seems that the outstanding properties of the aerogels of different origins significantly broaden the spectrum of their applications and open a way to their commercialization. On the way from the lab to the production the scale up of the supercritical extraction step is the main issue. Here the energy demand can be dramatically reduced by optimization of the extraction process, which is currently the main task for aerogel commercialization. Supercritical extraction (or drying process) overcomes the problems en- countered with traditional drying methods and preserves the high open porosity and superior textural properties of the wet gel in a dry form. Supercritical CO2 is the most appropriate fluid for supercritical drying of organic aerogels due to its mild critical point conditions along with its GRAS status. However, depending on the sample size and thickness the residence time in the extractor might be significant. Here significant efforts for the modeling of the process with the aim of the process optimization are still needed. SUPPORTED METALLIC NANOPARTICLES By SUPERCRITICAL DEPOSITION AND ThEIR APPLICATIONS IN ENERGy RELATED TRANSFORMATIONS

can Erkey Department of Chemical and Biological Engineering, Koç University; 34450 Sarıyer, Istanbul, Turkey; E-mail: [email protected]

Techniques such as impregnation, co-precipitation and sol-gel are commonly used to prepare supported nanoparticles. However, it is generally difficult to control the physical properties of the particles, such as the particle size and distribution, and the metal concentration in the materials. The supercritical deposition (SCD) technique involves the dissolution of a metal precursor in a supercritical fluid (SCF) and the exposure of a substrate to the solution. After adsorption of the precursor on the substrate surface, the metallic precursor is converted to its metal form using a number of methods resulting in nanoparticles at the surface of the substrate. Supercritical deposition especially using supercritical carbon dioxide (scCO2) has numerous advantages including the elimination of organic solvents and solvent residue on the substrates. Furthermore, faster mass transfer rates compared to liquids result in faster rates of deposition. A wide variety of metal nanoparticles including Pt,

Ru, Ni, and Cu@Cu2O were prepared using SCD on a wide variety of porous substrates including alumina, silica, carbon nanotubes, carbon and resorcinol formaldehyde aerogels. Uniformly distributed nanoparticles with a narrow particle size distribution are often obtained using SCD.

 53 54  SFE 2013 | workshop on supercritical fluids and energy

The size of the nanoparticles can be tuned by adjusting the supercritical deposition parameters such as metal precursor concentration in the fluid phase, temperature and the pressure of precursor adsorption, and the reduction temperature. The nature of the support material is also an important factor which effects the morphology of the nano particles. The thermodynamics of adsorption of the metal precursors are generally quantified by the adsorption isotherms for the precursors between the fluid phase and the porous substrate which usually follow Langmuir behavior. The kinetics of adsorption can adequately be described by using a mass transfer model based on diffusion in pore volume and local equilibrium at the surface of the support. In some cases, catalysts prepared using this technique have been found to be superior in activity to catalysts prepared by conventional techniques. The technique has recently been extended to preparation of supported bimetallic nanoparticles. Simultaneous Supercritical Deposition involves the dissolution of two metal precursors in a SCF and exposure of a substrate to this solution. Metal precursors are then physisorbed or chemisorbed on the support in the presence of SCF. Ad- sorbed metal precursors can then be decomposed to end up with supported metals or metal oxides through various processes. Carbon aerogel supported Pt-Cu alloy nano particles were prepared using the precursors dimethyl

(1,5-cyclooctadiene), platinum (II) (Pt(cod)me2) and bis (1,1,1,3,5,5,6,6,6-nonafluorohexane-2,4-diiminate) copper in the presence of scCO2. Binary adsorption isotherms were successfully predicted using the Ideal Adsorbed Solution Theory by using single component adsorption isotherm parameters alone. Alloy nanoparticles were formed via the thermal decomposition of metal precursors. The alloy- ing of Pt and Cu within the nanoparticles was character- SCFs&T for New Materials and Materials Processing  55 ized via XRD peak shifts at various Pt/Cu ratios, and XPS data pointed out that the surfaces of these Pt-Cu alloy nanoparticles were enriched in Pt. The particle size of the nanoalloys was found to increase with increasing copper fraction. Nevertheless, the particle size distribution was very uniform in all cases. Reactive supercritical deposition where the precursors chemisorb on the surface by reacting with the functional groups on the surface is another variation of the technique which can be used to prepare bimetallic systems. Recently, USY zeolite supported Ni-W hydrocracking catalysts were prepared via the simultaneous chemisorption of tungsten hexacarbonyl (W(CO)6) and Nickel (II) acetylacetonate or bis (1,1,1,3,5,5,6,6,6-nonafluorohexane-2,4-diiminate) nickel in the presence scCO2. Materials were then calcined at ambient pressure. FTIR indicated the chemisorption of metal precusors on USY zeolites. XRF analysis showed an increase in the W loading with an increase in both the initial W(CO)6 concentration in scCO2 and the deposition time. Temperature Programmed De- sorption experiments carried out using ammonia suggested that at the same loading the acid site distribution was different from catalyst prepared by incipient wetness. More- over, the proportion of the stronger acid sites was higher for the catalysts prepared using simultaneous supercritical deposition (53.3% of the total acid sites) as compared to that of the incipient wetness (33.2% of the total acid sites) indicating that the technique has potential to lead to development of catalysts with properties that are different than catalysts prepared by conventional techniques.

DENSE CO2 AS AN ENABLING MEDIUM FOR INTENSIFIED CATALyTIC AND PARTICLE FORMATION PROCESSES

Bala subramaniam Center for Environmentally Beneﬁ cial Catalysis, University of Kansas; 1501 Wakarusa Drive, Suite A110, 66047, Lawrence, KS, USA; E-mail: [email protected]

The foremost guiding principles underlying the sustainable process development include process intensification at mild conditions, minimization of waste and of adverse environmental footprints, and enhancement of inherent process safety [1]. Many groups, including ours, have uniquely exploited near-critical media to develop novel catalytic process concepts that admit these attributes. Central to these innovations is the recognition that with relatively moderate changes in pressure, it is possible to “tune in” unique fluid properties (liquid-like density and gas-like transport) with near-critical media. These concepts have numerous novel applications in heterogeneous catalysis such as: (a) facile desorption and transport of heavy molecules (including coke precursors) in mesoporous catalysts, alleviating pore-diffusion limitations and improving catalyst effectiveness; (b) enhancing product selectivity; and (c) exploiting the enhanced heat capacity of near-critical media to ameliorate parametric sensitivity in exothermic reactions. These features have been demonstrated for several classes of reactions such as isomeri- zations, hydrogenations, Fischer-Trøpsch synthesis and alkylations [1]. During the past decade, our group has exploited the pressure-tunable properties of gas-expanded liquids

 57 58  SFE 2013 | workshop on supercritical fluids and energy

(GXLs) in a variety of homogeneous catalytic systems [2]. At ambient temperatures, gases such as carbon dioxide

(CO2) and light hydrocarbons (such as propylene and ethylene) are close to their critical temperatures (i.e., between 0.7 -1.3 Tc). When these gases are mildly compressed (to tens of bars) at ambient temperatures, they dissolve in most conventional solvents and volumetrically expand them. The increased free volume of the GXL phases ac- commodates permanent gases such as O2, H2 and CO in unusually high concentrations. For example, O2 and light olefin concentrations are increased by one or two orders of magnitude in GXLs at ambient conditions, relative to conventional solvents, with similar increases in reaction rates [3]. This lecture will also highight several novel GXL- based catalytic reaction engineering concepts. These include (a) highly selective hydroformylation of higher olefins at mild conditions (~40 bars, 60 °C) employing soluble polymer-supported homogeneous catalysts which are easily retained in solution by membrane filtration [4]; (b) inherently safe liquid phase ethylene epoxidation process that totally eliminates CO2 formation as a byproduct [5]; (c) a spray reactor concept for the single step formation of high purity terephthalic acid with reduced solvent burning (i.e., reduced carbon footprint) [6].

Supercritical CO2 has also been exploited to synthesize nanomaterials of active pharmaceutical ingredients [7] and transition metal complexes with unique function [8]. This talk will describe a continuous GMP-compliant process for producing nanoparticles.

References [1] B. Subramaniam, C. J. Lyon and V. Arunajatesan, Applied Catalysis B: Environmental, 37(4) (2002) 279-292. SCFs&T for New Materials and Materials Processing  59

[2] P. G. Jessop and B. Subramaniam, Chemical Reviews, 107(6) (2007) 2666-2694. [3] M. Wei, G. T. Musie, D. H. Busch and B. Subramaniam, J. American Chemical Society, 124(11) (2002) 2513-2517. [4] Z. Xie, J. Fang, S. K. Maiti, W. K. Snavely, J. A. Tunge and B. Subrama- niam, AIChE J. (2013) DOI: 10.1002/aic.14142. [5] M. Ghanta, H-J Lee, D. H. Busch and B. Subramaniam, AIChE J., 59 (2013) 180-187. [6] M. Li, F. Niu, X. Zuo, P. D. Metelski, D. H. Busch and B. Subramaniam, Chemical Engineering Science (2013). Available in: http://dx.doi.org/ 10.1016/j.ces. 2013.09.004i. [7] B. Subramaniam, R. A. Rajewski and W. K. Snavely, J. Pharmaceutical Sciences, 86 (1997) 885-890. [8] C. A. Johnson, S. Sharma, B. Subramaniam and A. S. Borovik, J. Ameri can Chemical Society, 127(27) (2005) 9698-9699. Processing and production of new drugs and chemicals with compressed fluids PROCESSING AND PRODUCTION OF NEW DRUGS AND ChEMICALS WITh COMPRESSED FLUIDS

nora ventosa, santi sala, Elisa Elizondo, María Muntó, ingrid cabrera, Alba córdoba, Evelyn Moreno, paula Rojas, Lidia ferrer, Jaume veciana Institut de Ciència de Materials de Barcelona (CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Campus Universitari de Bellaterra, E-08193 Cerdanyola, Spain; E-mail: [email protected]

The obtaining of particulate micro and nanostructured molecular materials at large scale and the understanding of how to manipulate them at nanoscopic and supramolecular level are currently playing a crucial role in drug delivery and clinical diagnostics [1-3]. It has been observed that polymeric nanoparticles, micelles, microemulsions, nanosuspensions, nanovesicles, and nanocapsules are efficient drug carriers that can significantly help to develop new drug delivery routes, more selective and efficient disease-detection systems, drugs with a higher permeability to biological membranes with controlled released profiles, and to enhance their targeting towards particular tissues, cells or intracellular compartments. The potential of “bottom-up” strategies, based on molecular self-assembling, is much larger than that of “top-down” approaches for the preparation of such micro- and nanostructures. For instance, by precipitation procedures it should be possible to control particle formation, and hence particle size and size distribution, morphology and particle supramolecular structure. However, conventional precipitation/crystallizations from liquid solutions

 61 62  SFE 2013 | workshop on supercritical fluids and energy have serious limitations and are not adequate for producing such nanoparticulate materials at large scale with the narrow structural variability, high reproducibility, purity and cost needed to satisfy the high-performance requirements and regulatory demands dictated by the EMA and US FDA agencies. The solvent power of compressed fluids (CFs), either in the liquid or supercritical state, can be tuned by pressure changes, which propagate much more quickly than temperature and composition solvent changes. Therefore, using compressed solvent media, it is possible to obtain supramolecular materials with unique physicochemical characteristics (size, porosity, polymorphic nature morphology, molecular self-assembling, etc.) unachievable with classical liquid media [4]. Small changes in temperature and pressure of CFs result in large but homogenous changes in the fluid’s density, and hence in its solvent power. This tunable range in density (solvation ability) cannot be achieved so easily with any conventional liquid solvent.

The most widely used CF is compressed CO2 (cCO2), which is non-toxic, non-flammable, cheap and easy recyclable. It has gained considerable attention, during the past few years as a “green substitute” to organic solvents and even to water in industrial processing. During the past few years, CFs based technologies, in particular precipitation procedures, are attracting increasing interest for the preparation of particulate molecular materials with application in the field of drug-delivery and nanomedicine [5-10]. In this presentation a simple one-step and scale-up methodology for preparing multifunctional nanovesicle- bioactive conjugates will be presented. This method is readily amenable to the integration/encapsulation of multiple components, like peptides, proteins, enzymes, into the vesicles in a single-step yielding sufficient quantities SCFs&T for New Materials and Materials Processing  63 for clinical research becoming, thereby, nanocarriers to be used in nanomedicine for drug delivery purposes. A couple of examples of novel nanomedicines prepared by this methodology will be presented and their advantages discussed [11,12].

References [1] M. E. Davis, Z. Chen, D. M. Shin, Nature Reviews-Drug Discovery, 7 (2008) 771-782. [2] P. Couvreur, C. Vauthier, Pharmaceutical Research, 23 (2006) 1417-1450. [3] D. Peer, J. M. Karp, S. Hong, O. C. Farokhzad, R. Margalit, R. Langer, Nature Nanotechnology, 2 (2007) 751-760. [4] E. Reverchon, R. Adami, J. Supercritical Fluids, 37 (2006) 1-22. [5] K. Mishima, Advanced Drug Delivery Reviews, 60 (2008) 411-432. [6] M. Cano-Sarabia, N. Ventosa, S. Sala, C. Patiño, R. Arranz, J. Veciana, Langmuir, 24 (2008) 2433-2437. [7] E. Elizondo, S. Sala, E. Imbuluzqueta, D. González, M. J. Blanco-Prie- to, C. Gamazo, N. Ventosa, J. Veciana, Pharmaceutical Research, 28 (2011) 309-321. [8] E. Moreno-Calvo, M. Muntó, K. Wurst, N. Ventosa, N. Masciocchi, J. Veciana, Molecular Pharmacology, 8 (2011) 395-404. [9] S. Sala, A. Córdoba, E. Moreno-Calvo, E. Elizondo, M. Muntó, P. Rojas, Mª A. Larrayoz, N. Ventosa, J. Veciana, Crystal Growth Design, 12 (2012) 1717-1726. [10] E. Elizondo, J. Larsen, N. Hatzakis, I. Cabrera, J. Ingrid, J. Veciana, D. Stamou, N. Ventosa, J. American Chemical Society, 134 (2012) 1918- 1921. [11] N. Ventosa, L. Ferrer-Tasies, E. Moreno-Calvo, M. Cano, M. Aguilella- Arzo, A. Angelova, S. Lesieur, S. Ricart, J. Faraudo, J. Veciana, Lang- muir, 29 (2013) 6519-6528. [12] I. Cabrera, E. Elizondo, E. Olga; J. Corchero, M. Mergarejo, D. Pulido, A. Cordoba, E. Moreno-Calvo, U. Unzueta, E. Vazquez, I. Abasolo, S. Schwartz, A. Villaverde, F. Albericio, M. Royo, M. Garcia-Parajo, N. Ventosa, J. Veciana, Nano Letters, 13 (2013) 3766-3774. Hypolipemiant, anti-obesity and antitumor activities of supercritical extracts hyPOLIPEMIANT, ANTI-OBESITy AND ANTITUMOR ACTIVITIES OF SUPERCRITICAL ExTRACTS

sandra R. s. ferreira Department of Chemical and Food Engineering, Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil; E-mail: [email protected]

Natural products are a large source of components with biological activities. Those substances normally present high aggregated value and are important for different areas such as medicinal, food and nutritional supplements. On the other hand, obesity is a serious public health problem and is an important risk factor associated with the increase of cardiovascular disease, diabetes, chronic kid- ney disease, and some types of cancers. Overweight and obesity are associated with different conditions including hypertriglyceridemia and hypercholesterolemia which are caused by a disorder in the lipid metabolism and promote modifications in serum lipoprotein. Efforts towards the development of new effective drugs led to the discovery of hypolipidemic therapeutic agents from natural sources, which also raise interest for cancer treatment, because the therapies available are not completely able to reduce the disease progression and/or present high toxicity. Further- more, hypolipidemic or antihyperlipidemic agents are a diverse category of pharmaceuticals that are used for treatment of hyperlipidemia, which means an excess of cholesterol, triglycerides and glucose levels. In the present work different extracts from natural products were evaluated for their hypolipemiant, anti-obe-

 65 66  SFE 2013 | workshop on supercritical fluids and energy sity and antitumor abilities and the raw materials tested to provide the extracts varied from marine wildlife sources (pink shrimp residue) to medicinal plants (Cordia verbenacea and Casearia sylvestris). There are several usual procedures to obtain the extracts with biological active compounds from natural sources, such as low pressure (LP) methods and also supercritical (SC) technology. These procedures present advantages and disadvantages, and the effectiveness of each technique depends on the product quality and application, allied with the economical viability of the process. The anti-obesity and the hypolipidemic effects of the extracts (from pink shrimp residue and from C. sylvestris) were evaluated in vivo by means of submitting mice species (Swiss Mus musculus normal, Balb C and knocaut) to different assays. The anti-obesity characteristic was observed by treating the mice with a high-fat diet combined with the administration of the natural product extracts (from LP and SC processes) by oral gavage doses during 30 days. All animal procedures were conducted in accordance with legal requirements appropriate to the species and approved by local ethics committee. The weight of the animals during the treatment and the final total serum cholesterol, triglycerides and glucose levels were also monitored by means of mice blood analysis after the high fat diet treatment. The results indicated that the diet using SC extracts from shrimp residue at 50-100 mg/kg.d showed the best anti-obesity effect for knocaut and for normal mice, compared to LP extracts. The same behavior was performed by SC extracts from C. sylvestris, which presented the lowest mice body weight gain (best anti-obesity performance). Additionally, the normal mice group presented lower triglycerides and cholesterol levels, compared to knocaut when the shrimp residue extracts were applied. The best efficiency on triglycerides reduction observed from mice group treated with SC shrimp SCFs&T for New Materials and Materials Processing  67 extract was probably due to a synergistic action of astaxanthin, eicosapentaenoic (EPA) and docosahexanoic (DHA) fatty acids present in the extract. Additionally, highest glucose and triglycerides reductions were observed in animals treated with SC extracts from C. sylvestris, compared to the mice group treated with LP extract. Medicinal plants, such as C. verbenacea and C. sylvestris, have multiple popular uses in Brazil and other American countries, and are indicated for tumor treatment. In this study, SC extracts and LP extracts from both plants were tested to evaluate cytotoxic, antiproliferative, antitumor, nucleasic, antiangiogenic and apoptotic activities using experimental models in vitro and in vivo. To achieve this goal, experiments were performed evaluating the cytotoxic activity (MTT) in vitro by the viability of MCF-7 (breast cancer) cells and T-24 (urinary bladder carcinoma) cells. Besides, the effect of extracts on plasmid DNA through the nuclease activity was also evaluated. The in vivo antitumor activity was performed in Balb/C mice inoculated with ascitic Ehrlich tumor (AET) treated with the extracts at different concentrations and through the antiangiogenic activity of Gallus domesticus eggs fertilized by the chorioallantoic membrane essay (CAM) at concentrations of 1, 5 and 10 mg/ kg/day. The proapoptotic ability was also evaluated by annexin V essay using flow cytometry in AET cells taken from mice after extracts treatment. The results for SC extracts of C. Sylvestris reduced significantly the viability of MCF-7 and T-24 cells. Regarding the nuclease activity assessment, the SC extract showed a direct dose-dependent damage on DNA. The in vivo assays demonstrated that SC extracts of C. Sylvestris provided considerable antitumor activity. The extracts treatment caused significant inhibition of tumor growth in mice, causing increase in the average percentage of mice longevity (PAL). The annexin V essay revealed that the induced cell death by 68  SFE 2013 | workshop on supercritical fluids and energy

C. Sylvestris SC extracts was either by apoptosis or by necrosis. The SC extracts of C. Sylvestris also presented antiangiogenic activity by reducing significantly the percentage of blood vessels around the embryo. The results for SC extract of C. verbenacea provided a significant improvement in the cytotoxity effect for MCF-7 and EAC cells, and this high cytotoxity potential of the SC extract is due to the presence of α-humulene and trans-caryophyllene, which presents anti-inflammatory activity. C. verbenacea SC extract showed higher proapoptotic efficiency, by increasing 15% of unviable cells compared to LP extract. Interestingly, in none of the treatments the presence of necrotic cells was observed, sug- gesting a specificity of the treatment effect. One possible mechanism for the antitumor effect of SC extract of C. verbenacea can be attributed to the property of inhibiting COX-2 (ciclooxigenase-2 expression), which can activate the apoptosis of tumor cells, preventing their proliferation. Also, both C. verbenacea extracts (SC and LP) showed a high potential for inhibition of tumor growth in mice compared with the negative control, however the SC extract presented the best performance. Additionally, the best results obtained by the SC extract from C. verbenacea suggest that the cytotoxicity, as well as the antiproliferative, pro-apoptotic and antitumor activities could be attributable to the high content of α-humulene and trans-caryophyllene. The approach to evaluate the medicinal ability of natural extracts, described here by hypolipemiant, anti-obesity and antitumor activities, is important to reinforce the supercritical technology as a relevant process alternative to obtain valuable substances. The high-quality behavior described by the supercritical extracts emphasizes the need to continually open the areas of application of the supercritical fluids. OVERVIEW/ PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)

SCFs&T for Green Chemistry and Sustainable Technology New Developments and

Research in CO2 Capturing NEw DEVELOPMENTS AND

RESEARCh IN CO2 CAPTURING

María francisco, Adriaan van den Bruinhorst, Lawien f. Zubeir, cor J. peters*, Maaike c. Kroon Department of Chemical Engineering and Chemistry, Separation Technology Group, Eindhoven University of Technology; Den Dolech 2, 5612 AZ Eindhoven, Netherlands; E-mail: [email protected] *The Petroleum Institute, Chemical Engineering Department; P.O. Box 2533, Abu Dhabi, U.A.E.; E-mail: [email protected]

Over the past years, the increasing concern about global warming encouraged the scientific community to search and develop “zero emission” processes [1]. In this context, the reduction of carbon dioxide (CO2) release to the atmosphere became one of the most challenging research interests, because CO2 is considered to be the major cause of the greenhouse phenomenon.

The removal of CO2 from natural gas or the capturing of CO2 from flue gas, produced by post-combustion industries, became a big challenge due to the large volumes of CO2 and often the low CO2 concentration in the source gases. Most of the commercial absorption processes for CO2 use different types of alkanolamine solvents such as monoethanolamine (MEA), diethanolamine (DEA) or N-methyldiethanolamine (MDEA) [2]. Despite their good performance as solvents for chemical absorption, amine technologies show several important drawbacks in terms of operational cost, solvent regeneration and the suscep- tibility of amines to undergo thermal or oxidative degradation. The emissions of amines and degradation products

 71 72  SFE 2013 | workshop on supercritical fluids and energy to the atmosphere can cause serious damage to the environment as well as human health [3]. For this reason, the study of properties like their volatility became a very important issue for any work on solvent design in this area [4]. Three main approaches were found towards the development of new “green” solvents in carbon capture [5]:

a) The use of safer solvents for health and environment, e.g., solvents showing high biodegradability;

b) The use of so-called “bio-solvents” produced from readily available renewable resources;

c) The substitution of volatile organic solvents by less volatile ones such as ionic liquids (ILs) with negligible vapor pressure and, so far, with no detectable emissions into the atmosphere.

ILs attracted particular attention over the past years because they can be designed by choosing the cation-anion combination to pursuit the best performance as solvents for a certain application [6]. Together with their, in general, extremely low volatility, the so-called “Task Spe- cific Ionic Liquids” show promising advantages for CO2 capture compared to the conventional solvents. Examples include the more suitable physico-chemical properties and the higher degree of control of the solubility of gases in the IL. However, the “green” character of ILs can be questioned because most of them are produced from fossil resources and their synthesis cannot be considered as being “green”. Moreover, the high production and purification cost do not make ILs technology competitive with traditional solvents [7,8]. To overcome some of the limitations of ILs, Deep Eutectic Solvents (DES) were revealed by Abbott as versatile alternatives [9]. These low transition temperature SCFs&T for Green Chemistry and Sustainable Technology  73 mixtures (LTTMs) consist of at least one hydrogen bond donor (HBD) and one hydrogen bond acceptor (HBA) counterpart resulting in the formation of a liquid mixture showing an unusual low freezing point. Due to the high hydrogen bonding interaction, some of the promising characteristics of ILs as solvents are shared by DESs. They often possess an extremely low volatility, and their properties can be adjusted by selecting the nature and ratio of the hydrogen bonding pairs. They can also be designed to show a wide liquid range, water-compatibility, non-flammability, non- toxicity, biocompatibility or biodegradability. Finally, they can be easily prepared from readily available starting materials and becoming a competitive solvent in terms of cost. The first DES reported by Abbott [10] was formed by mixing urea with choline chloride. Since then, other similar DESs were prepared [11,12] and applied to different purposes as solvents or catalysts in reactions or bio- transformations [13], liquid separations [14] and metal electro-deposition [15]. Not much is known about these liquid mixtures; only the firstly reported one was very well characterized and studied. Taking advantage of the ability to tailor the phase behavior and physical properties of DES, studies on new combinations of hydrogen bond donor: acceptor have to be explored for the optimization of their performance as solvents for a certain application. The effect of different variables on their physical properties like temperature, water content or composition need to be investigated, as well as the thermodynamic parameters gov- erning their phase behavior. To the best of our knowledge, the only DES explored for CO2 capture and reported in literature is also the choline chloride + urea mixture [16]. In the search for eco-friendly and bio-renewable solvents, new mixtures have been investigated in this study. 74  SFE 2013 | workshop on supercritical fluids and energy

For that purpose, a new combination of choline chloride with a natural organic acid is studied. The choline cation was already explored for CO2 capture forming part of so- called “natural ionic liquids” [17], but never in a combination with an organic acid. The choline chloride salt presents the advantage over choline-based ILs of being a readily available starting material as it is considered as one of the essential nutrients in nature. The chosen organic acid is lactic acid, a natural carboxylic acid present in milk and vegetables, which can be easily produced by fermentation of carbohydrates [18]. The new type of low transition temperature mixtures in this work are formed by mixing both starting materials, i.e. choline chloride and lactic acid, in different ratios. A complete study on physical properties like density, viscosity, surface tension, and glass transition temperature has been executed in this work. In addition, the CO2 solubility in these liquid mixtures is studied to explore their suitability for CO2 capturing. An important parameter of a solvent for capturing

CO2 is the loading capacity of the solvent. However, a parameter equally important is the rate of dissolution of the gas in the solvent. In case the absorption rate is low, this will lead to quite large absorption facilities. In order to influence the kinetics of the absorption process, another aspect of this research comprises the application of high- gravity (HiGee) forces to reach thermodynamic equilibrium in a relatively short time, leading to much smaller separation units, which even can become mobile [19].

References [1] P. T. Anastas, M. M. Kirchhoff, Accounts of Chemical Research, 35 (2002) 686. [2] N. MacDowell, N. Florin, A. Buchard, J. Hallett, A. Galindo, G. Jackson, C. S. Adjiman, C. K. Williams, N. Shah, P. Fennell, Energy Environmen- tal Science, 3 (2010) 1645. SCFs&T for Green Chemistry and Sustainable Technology  75

[3] J. J. Renard, S. E. Calidonna, M. V. Henley, J. Hazardous Materials, 108 (2004) 29. [4] P. G. Jessop, Green Chemistry, 13 (2011) 1391. [5] C. Capello, U. Fischer, K. Hungerbühler, Green Chemistry, 9 (2007) 927. [6] R. D. Rogers, K. R. Seddon, Science, 302 (2003) 792. [7] S. Zhu, R. Chen, Y. Wu, Q. Chen, X. Zhang, Z. Yu, Chemical and Bio- chemical Engineering Quaterly, 23 (2009) 207211. [8] X. Zhang, X. Zhang, H. Dong, Z. Zhao, S. Zhang, Y. Huang, Energy Environmental Science (2012). [9] A. P. Abbott, D. Boothby, G. Capper, D. L. Davies, R. K. Rasheed, J. American Chemical Society, 126 (2004) 9142. [10] A. P. Abbott, G. Capper, D. L. Davies, R. K. Rasheed, V. Tambyrajah, Chemical Communications, 70 (2003). [11] Y. H. Choi, J. van Spronsen, Y. Dai, M. Verberne, F. Hollmann, I. W. C. E. Arends, G. J. Witkamp, R. Verpoorte, Plant Physiology, 156 (2011) 1701. [12] M. Francisco, A. van den Bruinhorst, M. C. Kroon, Green Chemistry (2012). [13] P. Domínguez de María, Z. Maugeri, Current Opinion in Chemical Bi- ology, 15 (2011) 220. [14] M. A. Kareem, F. S. Mjalli, M. A. Hashim, I. M. AlNashef, Fluid Phase Equilibria (2012). [15] P. Cojocaru, L. Magagnin, E. Gomez, E. Vallés, Materials Letters (2011). [16] X. Li, M. Hou, B. Han, X. Wang, L. Zou, J. Chemical & Engineering Data, 53 (2008) 548. [17] M. J. Muldoon, S. N. V. K. Aki, J. L. Anderson, J. N. K. Dixon, J. F. Brennecke, J. Physical Chemistry B, 111 (2007) 9001. [18] B. Dien, N. Nichols, R. Bothast, J. Industrial Microbiology & Biotech- nology, 27 (2001) 259. [19] Liang-Liang Zhang, Ji-Xin Wang, Yang Xiang, Xiao-Fei Zeng, Jian-Feng Chen, Industrial & Engineering Chemistry Research, 50 (2011) 6957- 6964. Combining Ionic Liquids and Compressed Gases for Sustainable Process and Energy Engineering Applications COMBINING IONIC LIqUIDS AND COMPRESSED GASES FOR SUSTAINABLE PROCESS AND ENERGy ENGINEERING APPLICATIONS

Aaron M. scurto Department of Chemical & Petroleum Engineering, University of Kansas; 1530 W. 15th St., 4132 Learned Hall, 66045, Lawrence, KS, USA; E-mail: [email protected]

Ionic liquids (ILs) are experiencing intense research focus due to their molecular flexibility producing a wide range of properties useful as solvents and functional materials. While their human and environmental impacts vary widely, their exceedingly-low volatility eliminates fugitive emissions which is one of the largest forms of industrial solvent- based pollution. Combining compressed or supercritical gases with ionic liquids has a number of beneficial effects for reactions, separations, and energy applications. Ionic liquids are insoluble in the majority of compressed gases except for the most polar gases at high pressures. More- over, these processes may have lower human and environmental impact than some conventional processes. Here, several of our group’s projects ranging from organic and homogeneous catalyzed reactions, to separations, novel absorption refrigeration, and novel Rankine/Power cycles, etc. will be overviewed. The synthesis of ionic liquids themselves in supercritical (SCF) or CO2-expanded solvents (CXLs) have been investigated and shown to have a number of processing advantages over conventional solvents especially the possibility to combine reaction and separation. Ionic liquids have negligible solubility in compressed CO2 while the reactants can be made miscible/ critical with CO2. CO2-expanded reaction mixtures also have control over reaction and separation with interme-

 77 78  SFE 2013 | workshop on supercritical fluids and energy diate vapor-liquid-liquid equilibrium. Other CXLs using Perspectives on the use polar aprotic solvents such as DMSO can be leveraged to of supercritical fluids in provide high kinetic rates and easy separation. When com- refrigeration cycles paring the complete life-cycle analyses of IL synthesis, both SCF and CXLs have advantages over conventional liquid processes. Biphasic Systems with Ionic liquids and compressed CO2 can provide an interesting platform for reactions and separations involving such homogeneous- ly-catalyzed reactions as hydrogenation and hydroformylation. Here, the ionic liquid acts as a support phase for the soluble catalyst and the temperature and pressure of the compressed CO2 phase affects the partitioning of reactants and products and increases the mass transfer rates into the IL phase. Alternatively, the ionic liquid may be able to provide advantages in the post-processing of reaction or extraction processes that use supercritical or

CO2-expanded liquids. The temperature, pressure, and amount of the ionic liquid may be used to induce phase behavior such as vapor-liquid-liquid or vapor-liquid equilibrium. The ability to tune the phase behavior of ILs and compressed gases to prevent IL from entering the compressed gas phase yields itself for engineering applications in refrigeration and power production. Here, the ionic liquid first absorbs a gas at a relatively low temperature and pressure, after which the solution is pumped to high pressures. Lower quality (temperature) waste heat can be used to liberate the dissolved gas producing a stream of high-pressure-high-temperature gas. This stream may then be used for two different types of energy applications. If the stream is then cooled and liquefied, it may be then sent through an expansion valve and heat exchanger to provide a cooling effect in novel type of absorption refrigeration. Regardless of the application, knowledge of chemistry, kinetics, thermodynamics, and transport phenomena are all required to optimize these systems. PERSPECTIVES ON ThE USE OF SUPERCRITICAL FLUIDS IN REFRIGERATION CyCLES

gustavo Bolaños School of Chemical Engineering, Universidad del Valle; Cali, Colombia; E-mail: [email protected]

During the last years, there has been a lot of interest in replacing the working fluids that are currently used in refrigeration cycles, by fluids that at the same time have low Ozone Depletion Potential (ODP), and low Global Warming Potential (GWP). ODP is defined as the capacity of a substance to react with the atmospheric ozone as compared to that of trichlorofluoromethane (R11), and GWP is defined as the global warming capability of a substance as compared to that of the same amount of carbon dioxide during a determined time span. Many of the refrigerants that are currently in use were introduced for replacing chlorofluorocarbons that were phased-out by the Montreal protocol because of their high ODP. Unfortunately, despite their low ODP, the replacing refrigerants have a high GWP. For example, the ODP of R134a, a widely used refrigerant, is zero, but its GWP is 1300. Because reducing emissions of greenhouse gases has been accepted worldwide as part of the effort to mitigate the climatic change, there is a need for new refrigerants with low ODP and GWP. Many synthetic refrigerants that have been recently developed have a GWP close to 150, and only few have lower GWP. However, the manufacture of these compounds is difficult because they have

 79 80  SFE 2013 | workshop on supercritical fluids and energy many isomers and thus the separation processes involved increase the cost of such substances. In addition, in some cases there is no knowledge on the final fate or on the mean lifetime of these compounds once released into the environment. In this context, the use of carbon dioxide as a working fluid both for subcritical and transcritical refrigeration cycles has gained a lot of attention. Historically, carbon dioxide was in fact one of the first refrigerants that were considered, and was used in commercial air conditioning systems until 1932, when chlorofluorocarbons were introduced. In those days, the limited technological capabilities for handling pressures above the critical pressure of carbon dioxide did not favor the use of this substance. Those limitations do not exist today. The interest in supercritical carbon dioxide as a working fluid was renewed in 1990, when several patents on transcritical cycles were awarded. Carbon dioxide presents favorable values of ODP and GWP (0 and 1, respectively). Its thermodynamic properties are such that they produce a high coefficient of performance, high compression efficiencies, and high volumetric refrigeration capacities (1.6 times that of ammonia, 5 times that of R22, and up to 8 times that of R12). Its high thermal conductivity and low viscosity, in particular in the supercritical region, make this substance an excellent heat transfer fluid. As a result, the size of carbon-dioxide-based refrigeration units is smaller than those of conventional ones, making it suitable even for mobile applications such as automotive air conditioning. In addition, as it is well known, carbon dioxide is not toxic, flammable or corrosive (if no water is present). As a refrigerant, it is designated as R744. Several challenges have to be faced before massive introduction of refrigeration systems based on supercriti- SCFs&T for Green Chemistry and Sustainable Technology  81 cal carbon dioxide can be accomplished. Some of them are technical, and some are non-technical. The technical challenges are related to the need on information about how the presence of lubricating oils that are used in installations based on the vapor compression cycle affects the performance of the cycle. Lubricant oil is needed in the compressor for preventing mechanical wearing of the pis- tons and other parts, for reducing noise, and for sealing and cooling the compressor. Phase equilibrium for mixtures of lubricating oils and carbon dioxide is thus an important issue that has been addressed in different publications, as well as how the concentration of lubricant oil in the carbon-dioxide-rich phase affects the thermodynamic and transport properties of the fluid, and how the carbon dioxide dissolved in the lubricating oil affects its viscosity and the performance of the system during its dynamic behavior. Several works have been dedicated to measurement, correlation and estimation of these properties for engineering purposes. Simulations considering pure carbon dioxide have shown that there is a pressure at the exit of the compressor that maximizes the coefficient of performance (COP), and that an optimum pressure exists for a given outlet temperature of the gas cooler. Correlations have been developed for optimum pressure, system COP and optimal gas cooler inlet temperature. Different cycle configurations have also been analyzed, such as the use of an internal heat exchanger, the use of two-stage compression with and without economizer, and the use of expanders for taking advantage of the work produced during expansion. The objective of these studies was to find a configuration that maximizes the cycle COP. At present, many papers have been published on the heat transfer mechanisms and pressure drop correlations of carbon dioxide during boiling 82  SFE 2013 | workshop on supercritical fluids and energy and cooling, in order to provide a theoretical basis for designing efficient components of refrigeration cycles. In this presentation, the main aspects of these topics will be reviewed. The use of supercritical fluids as working fluids in refrigeration cycles shows a high promise for commercial application in a short time. Several large companies are already committed to replacing conventional refrigeration systems by supercritical-carbon-dioxide-based systems, and the business opportunities in this field are growing very fast. OVERVIEW/ PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)

SCFs as Working Fluids and Process Technology Specifics of thermophysical properties and heat transfer at supercritical pressures SPECIFICS OF ThERMOPhySICAL PROPERTIES AND hEAT TRANSFER AT SUPERCRITICAL PRESSURES

igor pioro Faculty of Energy Systems and Nuclear Science, Institute of Technology, University of Ontario; 2000 Simcoe Street North, Oshawa, Ontario L1H 7K4, Canada; E-mail: [email protected]

It is well known that the electrical-power generation is the key factor for advances in any other industries, agriculture and level of living. In general, electrical energy can be generated by non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are a) thermal — primary coal and secondary natural gas; b) “large” hydro and c) nuclear. The rest of the energy sources might have visible impact just in some countries. In addition, the renewable-energy sources, for example, such as wind and solar and some others, are not really reliable energy sources for industrial-power generation, because they depend on Mother Nature and relative costs of electrical energy generated by these and some other renewable-energy sources with exception of large hydro-electric power plants can be significantly higher than those generated by non-renewable sources. For a sustainable and efficient power industry, thermal and nuclear power plants should be used as a basis for the electrical-energy generation, and these plants should use high-temperature and high-pressure working fluids including supercritical fluids. Therefore, specifics of heat

 85 86  SFE 2013 | workshop on supercritical fluids and energy transfer and thermophysical properties of supercritical fluids are very important for reliability and safety of new power plants. The use of Supercritical fluids (SCFs) in different processes is not new, and nor was it a human invention. Mother Nature has been processing minerals in aqueous solutions at near or above the critical point of water for billions of years. It was only in the late 1800’s when scientists started to use this natural process, called hydrothermal processing, in their labs for creating various crystals. During the last 50-60 years, this process (operating parameters ‑ water pressures from 20 to 200 MPa and temperatures from 300 to 500 ºC) has been widely used in the industrial production of high-quality single crystals (mainly gem stones). First works devoted to the problem of heat transfer (HT) at Supercritical pressures (SCPs) started as early as the 1930s. Schmidt et al. investigated free-convection HT of fluids at the near-critical point with the application to a new effective cooling system for turbine blades in jet engines. In the 1950s, the idea of using Supercritical water (SCW) appeared to be rather attractive for steam genera- tors/turbines in the thermal-power industry. The objective was to increase the total thermal efficiency of coal-fired power plants. At SCPs there is no liquid-vapour phase transition; therefore, there is no such phenomenon as critical heat flux or dryout. It is only within a certain range of parameters that deteriorated HT may occur. Therefore, the objective of this paper is a discussion on specifics of thermophysical properties and HT of SCFs in power-engineering applications. As a result of our studies into SCFs several heat- transfer correlations have been developed for SCW flowing SCFs as Working Fluids and Process Technology  87 upward in vertical bare tubes. The correlation based on the bulk-fluid-temperature approach appeared to be the most accurate one compared to other well-known 16 correlations. The proposed correlation has an uncertainty of ±25% for heat-transfer-coefficient values and about ±15% for calculated wall temperatures and is valid within the following range: Pressures 22.8‑29.4 MPa, heat fluxes 70‑1250 kW/m2, mass fluxes 200‑1500 kg/m2s, and tube inside diameters 3‑28 mm. However, the developed SCW correlation has less accuracy when applied to SC carbon-dioxide data. There- fore, a new correlation based on the wall-temperature approach was developed. This correlation has an uncertainty of ±30% for HTC values and about ±20% for calculated wall temperatures and is valid within the following range: Pressures 7.6‑8.8 MPa, heat fluxes 9.3‑617 kW/m2, mass fluxes 706‑3170 kg/m2s, and tube inside diameter 8 mm. Supercritical Carbon dioxide for use in advanced power cycles for high temperature solar, nuclear and fossil energy SUPERCRITICAL CARBON DIOxIDE FOR USE IN ADVANCED POwER CyCLES FOR hIGh TEMPERATURE SOLAR, NUCLEAR AND FOSSIL ENERGy

Mark Anderson University of Wisconsin-Madison; 1500 Engineering Dr. Madison WI, 53706, USA; E-mail: [email protected]

The importance of improved efficiency, reduced capital cost and higher operational temperature of future power production has led to renewed interest in studying advanced Brayton cycles utilizing supercritical carbon dioxide as the working fluid for high temperature energy conversion. Previous work conducted by Dostal et al. [1] has shown that the supercritical CO2 recompression cycle proposed by Feher [2] may be superior to other advanced high temperature cycles both from the standpoint of increased thermal efficiency as well as reduced size and cost of the required turbo-machinery components. These advantages make the cycle especially well-suited for any high temperature reactor system including the Sodium- Cooled Fast Reactor (SFR), the Fluoride Salt-Cooled High Temperature Reactor (FHR), the Lead-Cooled Fast Reactor (LFR) and the Very High Temperature Reactor (VHTR). The cycle is also of interest for use in Concentrating Solar Power (CSP) systems and has recently become of interest for use in fossil fuel power production to aid in CO2 reduction and sequestration. Sandia national laboratories [3] has begun testing supercritical CO2 compressors and turbines fabricated by Barber Nichols Inc. and has found promising initial results. Argonne national laboratory has analyzed several configurations coupled to advanced reactor de-

 89 90  SFE 2013 | workshop on supercritical fluids and energy signs and conducted initial studies on commercial PCHEs (Printed Channel Heat Exchangers) fabricated by Heatric. NREL along with several commercial partners has lead an effort to study the cycles performance for solar applications and is leading a US. Department of Energy effort to develop a 10MW s-CO2 turbine system for demonstration and future scale up. In order to realize these goals and demonstrate the applicability of this cycle several key fundamental phenomena need to be further understood. As an effort to advance this technology the University of Wisconsin is conducting research in the following different areas:

Highly instrumented heat transfer and pressure drop experiments on Printed circuit heat exchangers (PCHE) geometries near the critical point that can be analyzed with both 1D models and with more complex 3D CFD models. Based on the analysis of the experiments and the detailed CFD calculations, improvements to the models currently used in plant dynamics code calculations are being achieved and

optimization of heat exchanger passages for s-CO2 are being developed.

Development and implement of optimized fluid property algorithms within the Plant Dynamics Code and CFD codes to increase the calculation accuracy and reduce computational costs. One of the major issues with calculations of supercritical fluids is the use of highly accurate thermal physical property data, while this data is available through programs such as REFPROP it is computationally expensive to call at each itteration. Development of advanced lookup tables using bi-cubic spline methods can help to reduce the computational burden and still maintain the high accuracy required in calculations. SCFs as Working Fluids and Process Technology  91

Experiments to investigate the critical flow of the supercritical fluid through shaft seals and valve components. If a fluid is near the pseudo critical point or approaches and enters the two phase dome the assumptions of homogenous equilibrium flow may not hold. Research is currently underway to determine the discharge coefficient and critical mass flow rate for supercritical carbon dioxide at these conditions.

S-CO2 can be a highly oxidizing/corrosive fluid and if it is to be used as the working fluid in power plants with intended lifetimes of up to 40 year it is necessary to investigate the corrosion mechanisms on alloys. Corrosion coupled with the high temperatures and pressures of the cycle make the selection of appropriate materials a key area of research.

This talk will give a quick overview of some of the above research and how it relates to the future development of advanced s-CO2 Brayton power cycles. It will also elucidate the interesting phenomena associated with supercritical fluids.

References [1] V. E. A. Dostal, The supercritical carbon dioxide power cycle: Compa- rision to other advanced power cycles, Nuclear Technology, 154 (2006) 23. [2] E.G. Feher, The Supercritical Thermodynamic Power Cycle. In: Doug- las Paper nº 4348, presented to the IECEC. August 12-17, 1967. Miami Beach, Florida, USA.

[3] S. A. Wright, P. Pickard, R. Fuller, Early supercritical CO2 compression loop operation and test results (2008). [4] A. Moisseytsev et al., Comparison of heat exchanger modeling with

data from CO2-to-CO2 printed circuit heat exchanger performance tests. In: International Congress on Advances in Nuclear Power Plants 2010, ICAPP 2010, June 13-17, 2010. San Diego, CA, United States: American Nuclear Society. 92  SFE 2013 | workshop on supercritical fluids and energy

[5] A. Moisseytsev and J. J. Sienicki, Development of the ANL Plant Supercritical CO extraction of Dynamics Code and Control Strategies for the Supercritical Carbon 2 Dioxide Brayton Cycle and Code Validation with Data from the Sandia biological substrates: from the Small-Scale Supercritical Carbon Dioxide Brayton Cycle Test Loop, laboratory to the industrial ANL-ARC-218, 2011, Argonne National Laboratory. application [6] A. Moisseytsev and J. J. Sienicki, Development of a Plant Dynamics Computer Code for Analysis of a Supercritical Carbon Dioxide Brayton Cycle Energy Converter Coupled to a Natural Circulation Lead-Cooled Fast Reactor, ANL-06/27, 2006, Argonne National Laboratory. [7] G. Cao, V. Firouzdor, K. Sridharan, M. Anderson, and T.R. Allen, Corro- sion of Alloys in High Temperature Supercritical Carbon-Dioxide, Cor- rosion Science, 60 (2012) 246. SUPERCRITICAL CO2 ExTRACTION OF BIOLOGICAL SUBSTRATES: FROM ThE LABORATORy TO ThE INDUSTRIAL APPLICATION

José M. del valle Departamento de Ingeniería Química y Bioprocesos, Pontiﬁ cia Universidad Católica de Chile; Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile; E-mail: [email protected]

Despite extraction of valuable compounds from biological substrates using supercritical (sc) CO2 as a replacement of conventional organic solvent has been an industrial reality for more than three decades, there is reluctance in adopting this high-pressure technology because of the wrong perception that scCO2 extraction is not fully competitive. This presentation analyzes economics of scCO2 extraction of vegetable oil from prepressed seeds. This example can be used as case study because of the availability of a mathematical model of the extraction process that can be applied for process simulation purposes. Pre- pressed oilseeds have an interconnected network of pores that are filled with part of the oil expelled from fractured cells during pressing. The shrinking core model hypothe- sis applies to mass transfer in this substrate having as a parameter the effective diffusivity (Ed) within the pore network. Ed relates to a particle-size and scCO2-condition- independent, and pretreatment dependent microstructur- al factor. The shrinking core model is partially predictive in that there are dimensionless correlations proposed in literature for transport phenomena (film mass transfer, and axial dispersion) in a packed bed operating with supercritical fluids, and for the solubility of vegetable oils in scCO2.

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Estimates of extraction cost are anchored in a simulation Extraction of lipids and program describing the relationship between oil yield and carotenoids from algae extraction time in an industrial plant having ≥3 extraction by sub- and supercritical CO2 vessels. A typical cost of about 8 USD/kg oil was estimat- and dimethyl ether ed for scCO2 extractions at 40 ºC and 30 MPa. Optimal mass flow rate of CO2 depends on particle diameter, which should not be reduced necessarily below 2 mm. Extraction cost depends little on the length-to-diameter ratio of the vessels. For a same total volume of extraction vessels, the cost diminished as the number of vessels increased. For the same plant productivity, the cost diminished when increasing extraction pressure above 30 MPa. Economies of scales reduce cost when plant size increased. Simula- tion results are not properly accounted for in laboratory and pilot plan runs using a single extraction vessel. ExTRACTION OF LIPIDS AND CAROTENOIDS FROM ALGAE

By SUB- AND SUPERCRITICAL CO2 AND DIMEThyL EThER

Motonobu goto, hideki Kanda Nagoya University; Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan; E-mail: [email protected]

Algae of various species contain valuable organic compounds. Algae are diverse group ranging from unicellular to multicellular forms. One of these is Undaria pinnatifida, a brown alga, commonly known as “wakame” in Japan. This edible seaweed is widely consumed, and has been part of the diet in many countries, especially Korea and Japan. Algae possess several functional properties such as antioxidant, anticancer, antiviral, and antiobesity properties. They also contain lipids and sulfated cell-wall polysaccharides such as fucoidans. On the other hand, microalgae are recently focused as a source of biofuel. They also contain functional compounds. To extract the functional compounds and lipids, organic solvent or supercritical carbon dioxide have been used. The extraction process usually requires drying and grinding process. We have applied supercritical carbon dioxide extraction for marine algae to recover fucoxanthin and lipids [1]. Then, we used subcritical water to recover fucoidans [2]. Lardon et al. [3] conducted a life cycle assessment of algal biodiesel production, and indicated that drying and n-hexane extraction steps consumed huge energy and made algal fuel production in a negative energy balance. They have, thus, suggested wet extraction as an alternative method. Then, we proposed the use of liquefied dimethyl ether

 95 96  SFE 2013 | workshop on supercritical fluids and energy

(DME) as solvent of lipids and hydrocarbons from wet microalgae containing over 90% water content. The DME extraction can be used for all microalgae types, e.g., Mi- crocystis aeruginosa, Botryococcus braunii, and Euglena gracilis.

Subcritical DME Extraction The DME extraction eliminates the need for drying, cell disruption, and solvent evaporation at high temperature; hence, it has advantages such as simpler system and low energy consumption. The proposed extraction uses DME which is the simplest form of ether and has the following characteristics: (a) high affinity to oily compositions and partial miscibility with water, (b) low normal boiling point (-24.8 °C), (c) approval from the European Food Safe- ty Authority as a safe extraction solvent for the production of foodstuff and food ingredients, and (d) resistance to autoxidation unlike other alkyl ethers. Because heats of seawater (15 °C) and sun-warmed water (45 °C) around the ambient temperature (30 °C) are converted into energy for DME extraction by DME sending pump, the total energy required by the DME extraction is only for DME sending pump. In other words, the DME extraction is a novel energy-saving system [4]. Moreover, we have already developed bench-scale equipment and verified the concept of DME extraction [4,5].

Experimental

For supercritical CO2 extraction, semi-continuous flow-type apparatus was used. About 5 g of dried pow- dered sample was loaded in a 10 mL extractor vessel. Dry sample was milled using IKA-Werke mill and then sieved using a mesh size of 60. For subcritical water extraction, batch reactor or semi-continuous flow-type apparatus was SCFs as Working Fluids and Process Technology  97 used. Electric heater or microwave heating system were used to heat-up the extractor. For subcritical DME extraction, simplified flow-type apparatus was used. Wet microalgae (water content were over 80%) were placed in the lower half of a cylindrical extractor, while glass beads (0.71-0.99 mm diameter) were placed at the upper half of the extractor. The extractor was pressure-resistant glass coated with poly- carbonate. First, liquefied DME was then supplied to the extractor and the flow rate was adjusted by a back-pressure regulator. At a predetermined point of temperature and pressure, liquefied DME was passed through the extractor at a flow rate of 10 ml/min at 20 °C [6].

Results

1. Supercritical CO2 extraction The recovered amount of fucoxanthin increased at low temperature, and high pressure under supercritical conditions. The maximum percent recovery reached 80% at 40 °C and 40 MPa. The recovery of fucoxanthin is strongly related to the density of supercritical carbon dioxide which normally increases with increasing pressure and decreasing temperature and has a positive correlation with solvating power. It is expected that the recovery of fucoxanthin also increased with increasing density of supercritical CO2, however, at 25 °C, low yield was obtained due most likely to lower diffusivity of liquid CO2. It is also likely that an increase in temperature above 50 °C might have caused degradation of fucoxanthin, a thermally labile compound. The use of cosolvent such as ethanol was also reported to improve scCO2 extraction yield of fucoxanthin. The drawbacks of using such cosolvent, however, include costly and tedious separation of the solvent from the extracts and coextraction of some unwanted compounds such as chlorophyll in the products. 98  SFE 2013 | workshop on supercritical fluids and energy

2. Subcritical DME extraction Materials processing by Based on extraction yields of the two solvent ex- Supercritical Carbon Dioxide traction systems, the DME system was over 97.0% of the Powderization, Impregnation — Bligh-Dyer’s system in extraction rate, which suggests that Achievements and challenges the yields from the two procedures, which are completely different, was approximately the same. Also the element compositions, molecular weight distributions, and GC-MS spectra of extracts by both extractions are almost the same (Kanda et al. [7,8]).

Acknowledgments A part of this research was supported by Industrial Technology Research Grant Program in 2009 (Project ID: 09B40009c, H. Kanda) from New En- ergy and Industrial Technology Development Organization (NEDO) of Japan.

References [1] A. T. Quitain, T. Kai, M. Sasaki, M. Goto, Supercritical Carbon Dioxide Extraction of Fucoxanthin from Undaria pinnatifida, J. Agricultural and Food Chemistry, 61 (2013a) 5792-5797. [2] A. T. Quitain, T. Kai, M. Sasaki, M. Goto, Microwave-Hydrothermal Ex- traction and Degradation of Fucoidan from Supercritical Carbon Di- oxide Deoiled Undaria pinnatifida, Industrial & Engineering Chemistry Research, 52 (2013b) 7940-7946. [3] L. Lardon, A. Hélias, B. Sialve, J-P. Steyer and O. Bernard, Life-cycle assessment of biodiesel production from microalgae, Environmental Science & Technology, 43 (2009) 6475-6481. [4] H. Kanda, Super-energy-saving dewatering method for high-specific- surface-area fuels by using dimethyl ether, Adsorption Science & Tech- nology, 26(5) (2008) 345-349. [5] H. Kanda and H. Makino, Energy-efficient coal dewatering using liquefied dimethyl ether, Fuel, 89 (2010) 2104-2109. [6] H. Kanda and P. Li, Simple extraction method of green crude from natural blue-green microalgae by dimethyl ether, Fuel, 90 (2011) 1264- 1266. [7] H. Kanda, P. Li, T. Ikehara and M. Yasumoto-Hirose, Lipids extracted from several species of natural blue-green microalgae by dimethyl ether: extraction yield and properties, Fuel, 95 (2012) 88-92. [8] H. Kanda, P. Li, T. Yoshimura and S. Okada, Wet extraction of hydrocarbons from Botryococcus braunii by dimethyl ether as compared with dry extraction by hexane, Fuel, 105 (2013) 535-539. MATERIALS PROCESSING By SUPERCRITICAL CARBON DIOxIDE POwDERIzATION, IMPREGNATION — AChIEVEMENTS AND ChALLENGES

Eckhard Weidner Ruhr University; Universitaetsstr. 150 IB6/126, D-44780, Bochum, North-Rhine Westfalia, Germany; E-mail: [email protected]

The specific and unique properties of carbon dioxide are offering new pathways to materials with new properties by processes with considerable savings of energy and other resources. Particle generation by supercritical technologies was a major field of research and development in the past three decades, resulting in hundreds of publications and patents and some industrial applications. Processes like

CO2-assisted spray generation, spray drying, spray freezing, spray agglomeration, spraying of melts, precipitation/ crystallization from supercritical solutions are well understood. CO2 may act as solvent or antisolvent, lower melting points, is reducing viscosities and/or interfacial tension, helps mechanically to form fine dispersed sprays, acts as blowing/cooling/freezing media, inertises and allows to structure particles as needles, micro- or nanofoams, hollow spheres or even solid spheres. The particles may also be deposited on solid substrates, forming a film. Not only pure substances are modified with respect to particle size and particle size distribution, but in recent years methods to generate composites are in the focus of numerous research groups. Processes and formulations for encapsulat- ing solids, liquids or gases into so-called core-shell systems have been developed and successfully demonstrated.

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A few products have found their way into the markets. An example is micronized chocolate which, following the PGSS-approach (Particles from Gas Saturated Solu- tions), is produced by mixing molten chocolate with CO2 under pressure, expanding it in a nozzle to generate small droplets, which are very rapidly crystallizing by reducing the temperature via the co-expanding CO2. The process allows generating specific forms of crystals (ß-V) which together with the small size of the particles (1 to 30 µm) results in a very unique mouth feeling. The micronized chocolate is used to manufacture soft ice cream. Open questions for research are how formation and stability of dispersions (aerosols, gels, suspensions, emulsions, foams and so on) is influenced by supercritical fluids. Dependencies between the properties of such dispersions and the form, crystallinity and morphology of precipitating solid composites have to be investigated experimentally. Theoretical approaches for modeling phase behavior, compositions and transport properties of such complex systems are required for a knowledge- and science-based approach for designing materials, tailor-made for specific customer demands. A further, but less investigated process for modifying materials is impregnation. Impregnation is defined as process of imbuing or saturating with something. In technical applications impregnation is applied for modifying properties of bulk substances by physically or chemically binding impregnates to a bulk material or surface. Provid- ing impregnates in liquid solutes or from a gas phase at low to moderate pressures is state of the art, connected with disadvantages like low space yield in case of impregnation from gas phases, slow diffusion processes, long process times and high amounts of waste water in case of impregnation from liquid solutions. Prominent examples SCFs as Working Fluids and Process Technology  101 demonstrate that by applying supercritical fluids and pressure, impregnation time can be reduced, depths of impregnation can be increased and waste water is avoided. Between around 1990 to 2002 water-free dyeing of textiles was intensively studied both in the US and Europe. Although it has been proven in pilot plants that the process is ready for commercialization, major developments have been stopped. After some years of stagnation, Adidas and Nike have announced in 2012 to produce T-Shirts which are colored via CO2-dyeing in rather large industrial plants, operated in Thailand. It is reported that plants with dyeing autoclaves in the m³-range are used. Future has to show whether this is industrial breakthrough for

CO2-assisted dyeing. A further example is impregnating wood (e.g. as construction material for windows) with zinc-salts, making it resistant to water and biological degradation. A large industrial plant is operated successfully in Denmark since about 10 years. Impregnates might either be bound physically or chemically on the surface or in the bulk of a substrate. In case of physical sorption the process is mainly controlled by diffusion and adsorption, while in the second case chemical reaction rates have to be considered in addition. By near-critical gas, properties of the substrate, (e.g glass transition temperature) are modified. Gas induced swelling of the substrate widen diffusion pathways and impregnates dissolved in CO2 may rapidly and deeply penetrate. Shrinkage of the substrate during expansion might precipitate and entrap impregnates physically. Depending on the type of substrate and impregnate chemical reactions between the two components may take place in parallel. An example is the impregnation of leather with Chromium or Alumina. Additionally to the above 102  SFE 2013 | workshop on supercritical fluids and energy

described physical effects CO2 is modifying the pH-value of the tanning solution. The chemical reaction between chromium and proteins of the skin starts at a pH of about 2,8 and has to be increased to approx. 4 during the impregnation to avoid extensive swelling and destruction of the hide. It was demonstrated that at CO2-pressures above 3 MPa leather of excellent quality can be achieved after 2 to 3 hours, which is only 15 to 25% of the conventional time for tanning. As the specific properties of the CO2-process allow fine tuning of the pH-value via pressure and assists the reaction between chromium and proteins, chromium is be dosed in stoichiometric concentration. Thus the process is free of waste water containing chromium ions. In parallel more than 90% of the waste-water is avoided. In a pilot plant with a volume of 1,7 m³ it was demonstrated that the process is technically and commercially feasible. The return on investment might be as low as two years. Although supercritical assisted impregnation is already successfully applied in industry, the knowledge of the underlying physical and chemical principles is limited. Research and development is done only in a few groups — additionally the systems are very complex. Understand- ing the interaction of impregnates (often containing several chemical species, additives and solvents) with supercritical fluids as well as the interaction with the substrate is experimentally, theoretically and intellectually challenging. As multicomponent — multiphase systems are involved, experiments and analytics are time consuming and expensive. Theoretical descriptions of phase behavior and transport properties are often not (yet) available. Nevertheless industrial applications indicate that efforts in basic research promise to be worthwhile, of high interest and for sure of scientific and probably of commercial benefit. PANEL PRESENTATIONS

Panel I: Bio-based fuel processes Lessons Learned from Supercritical Water Upgrading of Crude Oil — Application to Biomass Liquefaction and Upgrading LESSONS LEARNED FROM SUPERCRITICAL wATER UPGRADING OF CRUDE OIL — APPLICATION TO BIOMASS LIqUEFACTION AND UPGRADING

Michael T. Timko Worcester Polytechnic Institute; 100 Institute Road, 01609, Worcester, MA, USA; E-mail: [email protected] hydrothermal liquefaction (HTL) of biomass has many advantages over other thermochemical biomass technologies, including superior energy efficiency (especially for high moisture content resources) and superior bio-oil product characteristics. Nonetheless, advances in this field have been limited due to the challenges associated with performing experiments and scale-up demonstrations. Specific challenges include understanding the complex chemistry associated with biomass feedstocks containing carbohydrates, lignin, and potentially proteins; difficulties pumping biomass slurries to HTL pressures at laboratory and pilot reactor scales; corrosion and precipitation associated with the inorganic content of biomass; difficulties analyzing the complex heat and mass transfer dynamics associated with HTL processes; catalyst failure due to sulfur or nitrogen poisoning. For these reasons, HTL has failed to live up to its considerable commercial potential. In this talk, I will examine parallels between HTL and a kindred technology, supercritical water upgrading (SCWU) of crude oil. Like HTL, SCWU seeks to use the unique physicochemical properties of water near the critical point to add value to a carbon-rich resource. Compared to biomass, crude oil contains far fewer distinct chemical functionalities; is a liquid at ambient conditions; contains limited inorganic

 105 106  SFE 2013 | workshop on supercritical fluids and energy components and therefore poses reduced corrosion risk; High pressure in synthetic fuel demonstrates partial miscibility with SCWU. My talk will production pathways embrace the building SCWU literature, but will focus on work performed at MIT in the past 4 years. The work at MIT has combined experimental rate and product measurements with reaction modeling and transport simulation to develop an integrated understanding of the most important physical and chemical phenomena taking place during SCWU. The lessons learned from SCWU will then be used to analyze future directions and opportunities for HTL. hIGh PRESSURE IN SyNThETIC FUEL PRODUCTION PAThWAyS

nicolaus Dahmen Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology (KIT); Hermann-von-Helmholtz-Platz 1, 76344, Karlsruhe, Baden-Württemberg, Germany; E-mail: [email protected] high pressure is involved in various processes under development to provide renewable energies and materials, as e.g. in concentrated solar power and fuels as well as in geothermal energies and carbon dioxide deep site storage. Also, in the case of biomass utilization pressurized systems play an important role e.g. in hydrothermal conversion of wet or thermochemical conversion of dry materials like e.g. pyrolysis, gasification, gas cleaning and syntheses of chemicals and fuels. The impact and benefits taken by application of pressure are manifold. At the example of a process for synthetic fuels and chemicals production, so- called second generation biofuels & chemicals, the application of pressure in different parts of the process chain is presented and discussed. Firstly, high pressure gasification is introduced. Here, the aim of the elevated pressure is to produce synthesis gas at pressures adjusted to those required in the subsequently following chemical synthesis process avoiding the expensive compression of syngas. In this case the gasifier is fed with solids and liquids directly at the desired pressure. Different type of equipment and technologies can be applied here like extrusion, dense fluid feeding or feeding of liquids or slurries. In this case, also gas cleaning has to be performed at the same pressure

 107 108  SFE 2013 | workshop on supercritical fluids and energy level. To optimize the energetic efficiency, temperature also has to be adjusted. Therefore a high temperature — high pressure gas cleaning process is introduced including filtration, sorption of sour gases and carbon dioxide as well as catalytic decomposition of small organic and nitrogen containing molecules, otherwise poisoning the chemical catalysts during synthesis. For Fischer-Tropsch-synthesis ca. 30 bar are required, for methanol or dimethylehter synthesis pressures of above 60 bar and even above 100 bar. New reactor designs and operation regimes also have been explored, like e.g. Fischer-Tropsch synthesis carried out in micro-structured devices at supercritical conditions. Gas- ification of biomass usually yields a carbon monoxide to hydrogen ratio around unity. To adjust this ratio to the specific synthesis demands, the water gas shift reaction is also to be facilitated under elevated pressures. For all these processes, the impact of pressure on the process fundamental has to be understood. For several aspects, reliable data are already available, for others systematic investigations are still required or in progress. For example, in gasification the fluid dynamics in entrained flow reactors or the atomization of solid and liquid fuels during injection are most sensitive to the system pressure. Experiments, difficult enough in pressurized reaction rooms of temperatures > 1000 ºC, are supported by appropriate modeling. Here, fluid dynamics have to be coupled with the chemical reactions occurring in a reasonable way. For application of elevated pressures, not only the operations conditions have to be optimized, but also the appropriate choice of materials, metrological devices, safety protocols has to be considered. In some cases, pressurized processes compete to such carried out at ambient conditions. In these cases, assessment has to be made if the usually higher expense for pressure vessels and equipment is balanced out by the Panel I: Bio-based fuel processes  109 expected benefits e.g. in regard to process efficiency (energy), improved yield, or smaller reactor volumes etc. To score the role of Supercritical Fluid Science and Technology for new processes in biofuels, an outlook on the emerging field of biofuels production and implementation is useful. Biomass is the only renewable carbon resource. On a long term, it primarily should be used for carbon based fuels and chemicals production, while heat and electric power can be provided by all other renewable energies. Thus, the further exploration, research and development of biomass conversion processes can be expected to attract even rising attention offering new and exciting fields for research and development. Biomass-derived solid fuel as green energy and its sustainable use BIOMASS-DERIVED SOLID FUEL AS GREEN ENERGy AND ITS SUSTAINABLE USE

yoshimitsu uemura, Wissam omar, noridah osman, Ahmad Rajab, suzana yusup Universiti Teknologi PETRONAS; Bandar Seri Iskandar, 31750, Tronoh, Perak, Malaysia; E-mail: [email protected]

Biomass is one of the promising renewable sources. Uti- lizing biomass may be able to mitigate the CO2 emission and fossil fuel depletion problems. Our research group is focusing on how to utilize lignocellulosic biomass as green energy. In this presentation, our recent efforts on torrefaction and its application will be introduced. Torrefaction is a low temperature treatment for lignocellulosic biomass at lower temperatures between 200 ºC and 300 ºC under an inert atmosphere, which has been found to be effective for improving the quality not only as a solid fuel, such as energy density and shelf life, but also as a feedstock for further conversion such as gasification and liquefaction. Currently, experimental torrefaction studies are mostly on woody and grass biomass; wood dusts, beech, eucalyptus, willow, larch, canary grass. We are investigating if this technology can be applicable to agricultural residues in Malaysia. The challenge of this technology is to provide cheap inert atmosphere. We are investigating if flue gas from boilers can be utilized for the injection gas of torrefaction. Possible application of the solid fuel produced by torrefaction will also be proposed.

 111 High pressure water reforming of biomass for energy and chemicals hIGh PRESSURE WATER REFORMING OF BIOMASS FOR ENERGy AND ChEMICALS

Ž. Knez, M. Škerget, E. Markočič, M. Knez Hrnčič, M. Ravber University of Maribor; Slomškovtrg 15, SI-2000, Maribor, Slovenia; E-mail: [email protected]

The conversion of biomass to biofuels and biobased chemicals has attracted a lot of attention recently, largely due to the environmental and socio-economic problems associated with the use of fossil fuels. In recent time many novel technologies have been introduced for conversion of biomass to energy and chemicals. Hydrothermal (HT) processes are considered as promising technologies for the conversion of biomass into biofuels and biobased chemicals.

BIOMASS hyDROThERMAL REFORMING The production of biobased chemicals and energy carriers is considered to be carbon-neutral, since the CO2 generated during processing can be absorbed by plants during their growth. Promising technologies for the conversion of biomass into biofuels and biobased chemicals are hydrothermal (HT) processes, which use sub- and supercritical water (SubCW, SCW) as processing medium. Generally, HT processes could be divided into four main processes: carbonization (HTC), aqueous phase reforming (APR), liquefaction (HTL), and gasification (HTG). In these processes water has the role of reactant, solvent, and also a catalyst. The main advantage over other processing

 113 114  SFE 2013 | workshop on supercritical fluids and energy methods includes ability to use wet biomass without pri- or dewatering and enables production of versatile chemicals and fuels in gaseous, liquid, or solid state. Extensive information about the fundamentals and mechanisms of HT reactions and state of the research is given in the literature [1]. The global increase in the production of biodiesel has led to a simultaneous increase in the amount of crude glycerol, the main by-product of biodiesel plants. The identification of high added value outlets for crude glycerol has become an active research topic. In the present study supercritical water reforming (SCWR) of glycerol (10 wt% aqueous solution) was performed at 673, 773 and 873 K and a pressure of 25 MPa for various residence times. The experiments were carried out in a high pressure continuous reactor and a comparison was made between non-catalyzed and catalyzed reactions. Cu/Zn catalyst and Cu/Zn doped with Al and Pb were used to improve the conversion of glycerol. It was found that Cu/Zn-Al,Pb catalyst, higher temperatures and longer residence times favor the gasification of glycerol, while Cu/Zn catalyst, lower temperatures and shorter residence times promote dehydration over gasification. The main gases produced during SCWR of glycerol are H2, CO2 and CO. The knowledge about the behaviour of these gases in water under different conditions of temperature and pressure is essential in designing the separation processes following the conversion reactions. Therefore we have studied the solubility of H2, CO2 and CO in water at high temperature and pressure, and the experimental data were correlated using various equations of state (Peng Robinson, van de Waals). The results show that the nature of the gas influences the behaviour of the water-gas binary system. Thus the solubility of CO2 in water increases with increasing pressure and decreasing temperature. Panel I: Bio-based fuel processes  115

Higher pressure also favors the solubility of H2, however higher amounts of H2 dissolve in water at higher temperature. The same effect of temperature was observed for CO, while pressure had an almost negligible effect on its solubility in water.

Chemicals from biomass Fast pyrolysis of biomass give dark brown organic liquids, commonly termed as bio oils (pyrolysis oil), which are chemically a complex mixture and/or emulsion of water and degradation products of lignin (e.g. guaiacols, cat- echols, syringols, vanillins), cellulose (such as levoglucosan, dehydrated sugars, di-sugars, furancarboxaldehydes), and hemicellulose (such as acetic acid, formic acid), depending on type of biomass feedstock and conditions of pyrolysis process. Details on the production and the typical properties of pyrolysis oils are presented elsewhere [2]. As an alternative fuel, biodiesel, produced from biomass, has been accepted throughout the world due to its several advantages. First of all, it is made from renewable sources, which are usually vegetable oils and animal fats. Biode- gradability, non-toxicity and low emissions in comparison to fossil fuels are further advantages which make bio fuels widely accepted as alternative fuels which are almost sul- phur and nitrogen free and also carbon dioxide neutral [3]. They are considered as promising alternative fuels for gasoline and diesel engines. For the systems pyrolysis oil+diesel+carbon dioxide and pyrolysis oil+tail water+ carbon dioxide as well as for systems hydrogen/pyrolysis oil and hydrogenated pyrolysis oil fundamental data were determined [2, 3]. The study of HT reactions of cellulose, a biomass model substance, in SubCW at temperatures 493, 523, and 573 K and autogenous pressure in batch reactor [4] showed 116  SFE 2013 | workshop on supercritical fluids and energy that the conversion to main products distributed in liquid, SCW technologies gaseous and solid phase is strongly dependent on the tem- for biomass refining perature and residence time. The maximal yield (51.4%) of water-soluble products was obtained at 523 K and reaction time of 5 min and the phase was composed mostly of cellulose decomposition products, such as sugar monomers and monomer degradation products (organic acids, 5-HMF, aldehydes etc.). Maximal yield (21.1%) of bio-oil was obtained at 523 K and reaction time of 60 min and consisted mainly of hydrophobic phenols and its derivatives, ketones, carboxylic acids, long-chain alkanes, etc. Gas yield was maximal (68%) at 573 K and 60 min, what indicates that non-catalytic gasification of biomass occurs only at temperatures above 573 K. Char formation was the most intensive at 523 K and 60 min. The results confirm that by targeted control of process conditions, selectivity of reactions to desired products could be influenced.

References [1] I. Pavlovič, Ž. Knez, M. Škerget, Hydrothermal Reactions of Agricul- tural and Food Processing Wastes in Sub- and Supercritical Water: A Review of Fundamentals, Mechanisms, and State of Research, J. Ag- ricultural and Food Chemistry, 6 (2013) 8003-8025. [2] M. Knez Hrnčič, R. H. Venderbosch, M. Škerget, Ž. Knez, Observation of phase behavior for bio-oil + diesel + carbon dioxide and bio-oil + tail water + carbon dioxide system, J. Chemical and Engineering Data, 58 (2013) 648-652. [3] M. Knez Hrnčič, R. H. Venderbosch, M. Škerget, L. Ilić, Ž. Knez, Phase equilibrium data of hydrogen in pyrolysis oil and hydrogenated pyrolysis oil at elevated pressures, J. Supercritical Fluids, 80 (2013) 86-89. [4] I. Pavlovič, Ž. Knez, and M. Škerget, SubcriticalWater — a Perspective Reaction Media for Biomass Processing to Chemicals: Study on Cel- lulose Conversion as a Model for Biomass, Chemical and Biochemical Engineering Quarterly, 7 (2013) 73-82. SCW TEChNOLOGIES FOR BIOMASS REFINING

Maria José cocero School of Industrial Engineering, Sede Mergelina Chemical Engineering Department, Valladolid University; 47011, Valladolid, Spain; E-mail: [email protected]

The development of biobased industries, supported in the biomass, needs a new philosophy to achieve a decentral- ized production as an alternative to the well-supported centralized petrochemical production plants. In order to accomplish these challenges, research has to enable the development of environmental compatible process, efficiently handling energy and reducing the equipment costs. These processes should be characterized by high yield and high selectivity, simplified number of processes steps by searching opportunities among new raw materials, and using clean solvents as water or carbon dioxide. The reduction of equipment costs involves the development of compact apparatus with reduced operation times; reducing the residence time from minutes to milliseconds allows a reactor volume reduction from m3 to cm3. The use of pressurized fluids has been proposed as an environmental compatible process to integrate the depolymerization-reaction-separation processes. Particularly, high-temperature pressurized water has proved to be a good solvent for clean, safe and environmentally benign organic reactions [1]. The main reasons that make the hydrothermal media a promising alternative for biomass processing are: (a) it is not necessary to reduce the water content in the raw

 117 118  SFE 2013 | workshop on supercritical fluids and energy material, thus avoiding energy losses; (b) the reaction medium permits the transformation of the different biomass fractions; (c) the mass transfer limitations are reduced or avoided, thus allowing faster reaction rates. Furthermore, the adjustable properties of the reaction medium work as a control factor for the reaction selectivity, avoiding the generation of by-products. High pressurized/supercritical water can be used for several depolymerization biomass processes as hydrolysis, transformation in high added value compounds, gasification, fractionation and oxidation to get energy.

Cellulose SCW Hydrolysis as pretreatment to achieve fermentable sugars The hydrolysis of cellulose is completed at subcritical temperatures, obtaining a high concentration of glucose and oligosaccharides, but the reaction has a low selectivity and needs bigger reactors and higher residence times [2]. Using subcritical water hydrolysis in the presence of a catalyst, the process can take place at a low temperature (150 ºC), but the residence time is increased up to 24 or 48 h [3]. The reactions of cellulose hydrolysis under supercritical conditions are fast, but, if the reactions are not controlled, a high quantity of derived products are yielded [4]. The selectivity of the cellulose hydrolysis in SCW water can be significantly improved by the reduction of the residence time. Cantero et al [5] have found out that the glucose selectivity obtained from cellulose was improved by using ultra-fast reactions in which a selective medium was combined with an effective residence time control. A selective production of glucose, fructose and cellobiose (50%) or total mono-oligo saccharides (>96%) was obtained from the cellulose in a reaction time of 0.03 s. Total cellulose conversion was achieved with a Panel I: Bio-based fuel processes  119

5-hydroxymethylfural concentration lower than 5 ppm in a novel micro-reactor. This study shows that the hydrolysis of cellulose to glucose and oligomers of glucose can be performed in residence times between 0.02-0.03 s in SCW with high selectivity of sugars (up to 98%). The keys to reducing the production of derived products when SCW is the reaction medium are: (a) effective control of the residence time, in order to stop the reaction after the total hydrolysis of cellulose and before the glucose degradation reactions; and (b) setting the conditions of the media to favor the hydrolysis reactions and disfavor the degradation reactions. Furthermore, the SCW glucose hydrolysis is a high selective reaction media to achieve pyruvaldehyde and lactic acid [6].

Fractionation of biomass using high pressurized water (HPW) The fractionation of biomass to obtain high valuable products as oils and antioxidants, hemicellulose, cellulose, bio-oils and lining could be achieved by a HPW stepwise process. The fractionation of grape seeds as a model biomass to understand the combination of extraction and a hydrothermal fractionation-hydrolysis process is presented. The grape seeds were extracted in a first step with ethanol/water (75%/25%) at 90 ºC obtaining ca. 13% of oil and 0.0446 g-GAE/g-grape seeds (66% of the maximum polyphenols), to obtain the maximum yield and antioxidant activity. Then grape seeds were treated with high pressurized water using three different temperatures: 250 ºC, 300 ºC and 350 ºC. The solid residue varied from 0.256-0.358 g/g, the Light Bio-oil from 0.081-0.157 g/g and High Bio-oil from 0.106-0.162 g/g. The first order kinetics for the hemicelluloses and celluloses in our system were k0 = 0.995 g/min with an activation energy Ea = 13849.6 J/mol. The flow 120  SFE 2013 | workshop on supercritical fluids and energy rate increases the mass transfer in the system improving Sustainable technologies the extraction; however, a maximum was found at a surface for oil-based second velocity of 2.3 cm/min. During the hydrolysis, the pH de- generation biorefineries creased from 5.5 down to 3.0 due to acetyl groups liberation. Finally, the carbonization of the grape seeds did not yield to clear nanosize structures as other materials do.

References [1] K. Arai, R. L. Smith, T. M. Aida, J. Supercritical Fluids, 47(3) (2009) 628-636. [2] T. Rogalinski, T. Ingram, G. Brunner, J. Supercritical Fluids, 47(1) (2008) 54-63. [3] Z. Fang, F. Zhang, H.-Y. Zeng, F. Guo, Bioresource Technology, 102(17) (2011) 8017-8021. [4] M. Sasaki, K. Goto, K. Tajima, T. Adschiri, K. Arai, Green Chemistry, 4(3) (2002) 285-287. [5] D. Cantero, M. D. Bermejo, M. J. Cocero, Bioresource technology, 135 (2013) 697-703. [6] D. Cantero, M. D. Bermejo, M. J. Cocero, J. Supercritical Fluids, 75 (2013) 48-57. SUSTAINABLE TEChNOLOGIES FOR OIL-BASED SECOND GENERATION BIOREFINERIES

n. cotabarren, p. hegel, s. pereda Planta Piloto de Ingeniería Química, Universidad Nacional del Sur (PLAPIQUI-UNS-CONICET); Camino La Carrindanga Km 7 – CC 717, 8000, Bahía Blanca, Buenos Aires, Argentina; E-mail: [email protected]

A biorefinery is, by definition, the integrated production of food, fodder, chemicals, materials, goods, and fuels by means of bio- or physicochemical processing of biomass. In that sense, human bodies are a good example of biomass processing to recover energy and chemicals to produce materials; however, the atomic efficiency of modern societies is quite low. Even worse, as can be seen in big cities, the richer the population is, more residues it produces. Losses in the feed chain have not yet been seriously examined. In summary, the second-generation biorefineries not only should process non edible biomass, but also it should push forward the gain of edible biomass resources. In that sense, new technologies for biomass recycling and residues processing are needed to enhance the bio - economy matrix. It is important to look at food processing industrial centers and urban residues. For example, the great increase of worldwide production of soybean and sunflower oil, impacted not only in the oil market but also in the oil refining by-products (phospholipids sludge and distillates of the deodorizer), which prices are rapidly changing. Even though these residues contain high-added value products, their cost are decreasing, becoming sometimes a waste with disposal-associated problems. Furthermore,

 121 122  SFE 2013 | workshop on supercritical fluids and energy sludge processing to recover oil or phospholipids is complex. Because of its high viscosity and poor flow properties (sticky behavior), its processing needs large volumes of solvent, and consequently, it is expensive. An alternative sustainable technology is the direct alcoholysis of phospholipids and vegetable oil (triglycerides) occluded in the wet gum using supercritical ethanol to produce fatty acids ethyl esters (FAEE). Oil gums contain approximately 45% water, 25% oil and 30% phospholipids. Therefore, the conventional alkaline process is a non-viable alternative to produce fatty esters from SOGs. By contrast, the transesterification process by supercritical alcoholysis is an interesting option for this unconventional and low-cost feedstock [1]. On the other hand, with respect to high added value chemicals, in biodiesel processing plants acylglycerols can be economically produced. Acylglycerols are common food emulsifiers and surface active agents in many industrial cleaning products. Commercial MG is obtained via an alcoholysis pathway in which either fatty acids or a fat are reacted with an excess of glycerol. The reaction products contain mainly mono-, di-, tri-glycerides (MG, DG, TG, respectively) and glycerol, but depending on the glycerol/fat ratio the MG composition fluctuates between 40 and 60% of MG [2]. A further refined MG up to around 90 wt% purity, also called “high mono”, is conventionally obtained by short path distillation of the reaction products at ca. 473 K and 0.01 mbar or less [2]. This process is expensive and recovers only part of the produced MGs. More- over, MG concentration higher than 96 wt% cannot be achieved by vacuum distillation because of interesterifi- cation reactions causes degradation of MG towards glycer ol and free fatty acids. Peter et al. [3] proposed an interesting alternative to obtain 99 wt% purity of MG from the acyl- glycerides mixture by means of supercritical fluid extrac Panel I: Bio-based fuel processes  123 tion using mixtures of carbon dioxide and propane as extraction solvents. An alternative pathway to produce MG, instead of transesterification, is the glycerolysis of fatty acid methyl esters. In this case the separation problem downstream of the reactor completely changes. Puri- fication of MG from a mixture of biodiesel can be carried out with pure CO2 as a green solvent [4]. CO2 presents complete solubility with fatty esters in a wide range of temperature and pressure, and exhibits partial miscibility with acylglycerols (both in liquid and supercritical state). This alternative appears as a promising process with direct application in the biodiesel and food industry. Nowadays strong regulations are set on oil-based biorefineries to use nonedible vegetable oils. In that respect, the urban residual oils and fats are an interesting source of fatty acids for biodiesel production. The commercial process to convert used cooking oil (UCO) to used cooking oil methyl esters (UCOME) is a pretreatment of the oil with high content of fatty acids. The acid oil can be reacted with glycerol to produce a mixture of acylglycerols, which are fed in a transesterification plant, after its purification by vacuum distillation [5]. Due to the immiscibility of the reactants, the reaction rate is very low. In order to enhance the miscibility it is carried out at temperatures above 200 ºC, but the long residence time causes thermal degradation of the raw materials, which end up in highly contaminating ef- fluents. A phase equilibrium engineering of this reaction requires thermodynamics models able to predict the multiphase behavior. GCA-EoS is a group contribution with association model that has shown good traits to predict phase behavior of these types of mixtures. In this presentation, sustainable technologies for residues processing and vegetable oil recycling will be discussed. Moreover, also a high pressure technology for high purity mono- 124  SFE 2013 | workshop on supercritical fluids and energy glycerides recovery will be presented. Integration of the Biodiesel purification discussed technologies may contribute to pave the way using supercritical CO2 towards oil-based second generation biorefinery development. Finally, trends in the field of oil recycling and oil based fuels other than biodiesel will be discussed.

References [1] G. Soto, A. Velez, P. Hegel, G. Mabe, S. Pereda, J. Supercritical Fluids, 79 (2013) 62. [2] W. Fischer, DGF-Symposium in Germany (1998). [3] S. Peter, B. Czech, U. Ender, E. Weidner, US Patent 5 434 280 (1995). [4] G. Soto, P. Hegel, S. Pereda, III Iberoamercian Conference on Su- percritical Fluids, Cartagena de India, Brazil, 2013. [5] P. Felizardo, J. Machado, D. Vergueiro, M. J. N. Correia, J. Pereira Gomes, J. Moura Bordado, Fuel Processing Technology, 92 (2011) 1225. BIODIESEL PURIFICATION

USING SUPERCRITICAL CO2

Marcos L. corazza, papa M. ndiaye, Alexis M. Escorsin Federal University of Paraná; Francisco H dos Santos, 100, Curitiba, PR, Brazil; E-mail: [email protected]

Currently there is great interest in developing new methods and processes focusing on biodiesel production and purification. Regarding conventional transesterification process for biodiesel production the use of water for biodiesel washing aiming the removal of glycerol, diacyl- glycerol, monoacylglycerol, salt and other contaminants is expensive and request a high water to biodiesel ratio consumption. It is estimated that 3 L of water are used for 1 L of pure biodiesel produced. Thus, the development of new processes that minimize the water consumption for biodiesel production can be interesting from environmental and economic point of view. Due to the low solubility of glycerol, acylglycerols (MAG, DAG and TAG) and salts in supercritical CO2, it will be presented in this lecture that soybean biodiesel can be efficiently separated and purified from the reacting mixture (named crude biodiesel) by using supercritical CO2 injection. Initially, we have measured the phase equilibrium for the systems (m)ethanol(1) + glycerol(2) + CO2(3), at three different alcohol to glycerol molar ratios (12:1, 20:1 and 30:1) and (m)ethanol(1)

+ biodiesel(2) + CO2(3), at alcohol to biodiesel molar ratio of (3:1 and 8:1), at temperature ranged (303 K-353 K). The high immiscibility for the systems containing the glycerol was experimentally observed. For the systems (m)ethanol(1)

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+ glycerol(2) + CO2(3) the occurrence of vapor-liquid, Critical Fluids application liquid-liquid and vapor-liquid-liquid equilibrium were ob- for efficient processing of served. Regarding the biodiesel purification a given amount lignocellulose biomass as part of CO was injected using a variable-volume view cell con- 2 of an integrated biorefinery taining the mixture of crude biodiesel. The cell was then pressurized in the range of 6-12 MPa at temperature varying from ambient (298 K) to 323 K. The amount of carbon dioxide injected in the crude biodiesel varied from 20 wt% to 50 wt%. Two phases were formed at the end of the process. By mean of one-way valve, the lighter phase was sampled and diacyglycerol, monoacylglicerol, glycerol, biodiesel, sodium and methanol content were analyzed using Gel Permeation Chromatography (GPC) and gas chromatography (GC). Results were then compared to the conventional biodiesel production from a transesterification process. The characterization was done in accordance with the standards specification of the National Agency of Pe- troleum, Natural Gas and Biofuels (ANP/Brazil). An experimental design was performed to investigate the influence of carbon dioxide composition, pressure and temperature. Results obtained have showed that this process can be able to produce a biodiesel with low levels of diacylglyc- erol, monoacylglycerol, biodiesel (fatty acid methyl esters), sodium, glycerol and methanol. From the results obtained it can be seen that the temperature was the variable that most affects the purification of biodiesel while the carbon dioxide concentration and the pressure has a minor effect. The best condition was obtained at low temperature. In a general way, in this proposed process the obtained biodiesel presented lower levels of sodium, glycerol and methanol contents than the values specified by the National Agency of Petroleum, Natural Gas and Biofuels (ANP/ Brazil). This process represents a promising technique in further biodiesel downstream purification steps. CRITICAL FLUIDS APPLICATION FOR EFFICIENT PROCESSING OF LIGNOCELLULOSE BIOMASS AS PART OF AN INTEGRATED BIOREFINERy

Regina c. D. santos University of Birmingham; Edgbaston, B15 2TT, Birmingham, West Midlands, UK; E-mail: [email protected]

It is widely acknowledged that lignocellulose biomass derived from forestry, energy crops, agricultural and food processing residues represents a significant renewable resource that has yet to be exploited to its full potential. Fermentation, either liquid or solid state are accepted routes by which it is thought lignocellulose biomass can be up- graded to liquid and gaseous bioenergy carriers and eventually platform chemicals, reducing our current dependence on fossil fuels. However, the recalcitrant nature of lignocellulose reduces fermentation efficiency. Attempts to overcome the resistant structure of the biomass have led to extensive research in the area of ‘pre-treatment’. To date there are a large number of reports describing the application of acid, alkali, and other solvents, combined with a range of physical treatments. However most if not all, while breaking down the physical barrier, often induce the production of either naturally occurring or novel chemical intermediates that conspire to again reduce fermentation efficiency. The work currently being undertaken at the University of Birmingham, School of Chemical En- gineering will be presented, where researchers are evaluating and developing strategies to optimise biomass pre-treatment and therefore maximise the potential of lignocellulose utilisation in downstream fermentation.

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PANEL PRESENTATIONS

Panel II: New Materials and Materials Processing Synthesis of metallic nanoparticles using supercritical fluids SyNThESIS OF METALLIC NANOPARTICLES USING SUPERCRITICAL FLUIDS

M. crone, s. Müller, M. Türk Department of Chemical and Process Engineering, Karlsruhe Institute of Technology (KIT); Engler-Bunte-Ring 21, 76131, Karlsruhe, Baden-Württemberg, Germany; E-mail: [email protected]

In the 21st century, manufacturing as well as service industries must increasingly attempt to avoid production, use, and release of harmful substances into our environment. Furthermore, discovering environment-friendly and renewable energy sources is one of the major challenges in the present and future. As a result of these two factors new processes must be therefore environmentally friendly when employed at a large scale. During the last thirty years numerous technological advances indicate that the use of supercritical fluids (SCFs) enables the overcoming of these environmental problems and offers new and promising pathways for material processing. SCFs are characterized by densities very close to those of liquids and mass transfer properties lying between those of gases and liquids. Depending upon the fluid density, the fluid may be tuned to behave as a specific solvent for a specific substance at one pressure, but as a non-solvent at another pressure. SCF-based processes are characterized as environment-friendly due to the low-energy solvent and product recovery. In addition a solvent-free product can be obtained in a single processing step by partial system depressurization. These specific characteristics of SCFs can be exploited to design and synthesize new materials

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— in particular nanoparticles — for advanced performance in numerous applications. Nanoparticles, i.e. particles which have at least one dimension on the nanometer scale (1 to 100 nm) have become more and more important in a large number of technological important areas such as chemistry, energy, electronics, optics and pharmacology. Noble metal nanoparticles and, in particular, platinum (Pt) nanoparticles have demonstrated to be efficient catalysts for chemical reactions such as hydrogenation, hydration and oxidation [1]. They are often prepared by aqueous impregnation of a porous support with a metal-containing solution, followed by reductive treatment. Catalysts prepared by this procedure yield to metal particles with broad size distribution and to large volumes of waste water. A promising environment-friendly alternative to this conventional preparation route is the application of SCFs to achieve high dispersions of noble nanoparticles on porous supports (e.g. TiO2, Al2O3, Black Pearls, Carbon nanotubes) [2]. Material design using methods involving SCFs is achieved through two distinct processes. Particle formation can thus be based on either a physical transformation (e.g. rapid decompression, anti-solvent effect.) or a chemical reaction. In case of the second method, metallic nano particles can directly be deposited on various solid supports by Supercritical Fluid Reactive Deposition (SFRD) [3]. In this process, the SCF acts as a solvent, reaction and separation media. The SFRD technique involves the dissolution of the organometallic precursor in a SCF (e.g. scCO2) and the exposure of a support to the solution. After sufficient time for impregnation, the precursor will be trans- formed to its metal form with a reducing agent, such as hydrogen. Different methods can be used to convert the organometallic precursor to its metal form: a) chemical reduction in scCO2 with hydrogen, b) chemical reduction Panel II: New Materials and Materials Processing  133 at atmospheric pressure with hydrogen, c) thermal reduction in scCO2, and d) thermal reduction at atmospheric pressure in an inert atmosphere. Usually method b) was only used on selected samples for comparison while method a) was the preferred process. At the end of these experiments, the system is slowly depressurized and cooled down to ambient conditions. Since both, CO2 and the reaction products are in the gaseous state, phase separation can be easily realized and a solvent free product is obtained. Thus, the SFRD technique represents an integrated process that enables process intensification because it combines several steps of the conventional process. In our investigation, the influence of different organometallic precursors, various supports and reduction conditions on particle size, size distribution, and metal loading was investigated. The product was characterized by scanning and (high resolution) transmission electron microscopy (SEM and HRTEM), energy-dispersive X-ray spectroscopy (EDXS), powder X-ray diffraction (XRD), and ICP-OES analyses. First, this talk will give an introduction into the ba- sics of the SFRD process, including a short discussion of the solubility and the phase behaviour of the precursor in the SCF as well as of the adsorption behaviour of the precursor on the support. Based on this, typical results obtained from SFRD experiments are presented and discussed. In summary, the results of our investigations show that:

1) The average particle size and size distribution can be affected by type and amount of the precursor in the system, precursor reduction method and condition, surface properties (surface area and chemical nature) of the support [3].

2) The SFRD process enables the formation of uniform Pt, Pd, Au, Ag- and bimetallic (Au-Ag) nanoparticles. 134  SFE 2013 | workshop on supercritical fluids and energy

3) Adsorption behaviour determines the metal amount Supercritical Carbon Dioxide which can be deposited on the support. Drying of Silica Alcogel: 4) Pt- and Pt/Cu-catalysts prepared by SFRD exhibit- State-of-the-Art and ed an activity higher than reference samples pre- Outstanding Needs pared by conventional wet impregnation [4,5].

At the end of the talk the main conclusions and further perspectives are summarized and discussed.

References [1] C. J. Zhong, M. M. Maye, J. Luo, L. Han, N. Kariuki, Nanoparticles in catalysis, in: V. Rotello (Ed.) Nanoparticles: building blocks for nanotechnology. Kluwer Academics, Plenum Publishers; NY, 2004, 113. [2] C. Erkey, J. Supercritical Fluids, 47 (2009) 517. [3] V. Aggarwal, L. Reichenbach, M. Enders, Th. Muller, S. Wolff, M. Crone, M. Türk, S. Bräse, Chemistry European J., 19 (2013) 12794. [4] G. Incera Garrido, F. C. Patcas, G. Upper, M. Türk, S. Yilmaz, B. Kraushaar- Czarnetzki, Applied Catalysis A: General, 338 (2008) 58. [5] S. Lang, M. Türk, B. Kraushaar-Czarnetzki, J. Catalysis, 286 (2012) 78. SUPERCRITICAL CARBON DIOxIDE DRyING OF SILICA ALCOGEL: STATE-OF-ThE-ART AND OUTSTANDING NEEDS

Marc hodes Mechanical Engineering Department, Tufts University; 200 College Ave., Medford, MA, 02155, USA; E-mail: [email protected]

Aerogels are dry, nanoporous, nanostructured materials with unique and extreme properties including ultra-low density and thermal conductivity. To date the commercial focus of aerogels has been superinsulation. Indeed, heating and cooling of buildings in the United States, e.g., accounts for 15% of energy consumption and 32% of CO2 emissions and the superinsulating properties of commercially-available aerogel blankets can immediately and substantially reduce these numbers. Unfortunately, aerogel superinsulation is 10 times more expensive than conventional insulation; say, polyurethane. Hence, while the worldwide insulation market is about $40 billion, aerogels account for less than 1% of it and it is projected that the aerogel industry will grow to only $330 million by 2017. The two common techniques for removing the alcohol from the pores of a silica alcogel and replacing it with air thereby affording an aerogel are ambient pressure drying and supercritical carbon dioxide (scCO2) drying, the focus here. scCO2 drying enables extraction of solvent from a gel while preserving the delicate nanostructure of its solid skeleton by eliminating phase boundaries and thus capillary forces. Beneficially and unlike direct supercritical extraction, scCO2 drying is a low temperature and nonflammable pro-

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cess. However, scCO2 drying requires substantial infrastructure, i.e., expensive pressure vessels, fluid handling equipment, and process control hardware, and copious amounts of CO2. Moreover, scCO2 drying and CO2 recycling are cost- and energy-intensive and, importantly, drying is the rate-limiting step in the manufacture of aerogels.

We discuss the state-of-the-art in scCO2 drying of alcogels with a focus on the drying kinetics study recently completed at Tufts University. In this study we dried 5, 10 and 15 mm-thick x 56 mm OD x 220 mm-tall annuli of alcogel that were concentric with a 56 mm ID x 76 mm

OD annular gap through which scCO2 flowed. This was accomplished over a range of CO2 mass flow rates (1 kg/ hour to 5 kg/hour), operating pressures (100 bar to 138 bar), and operating temperatures (50 oC to 70 oC) using two different solvents, i.e., ethanol and methanol. Alcohol extraction rates were continuously measured for the first time.

The total mass flow rate of scCO2 plus alcohol leaving the reactor was measured using a Coriolis flow meter. Down- stream of this flow meter, the effluent flowed through a series of heated decompression valves and separated into liquid and vapor streams. The mass flow rate of liquid alcohol was measured using a collection beaker and balance. The mass flow rate of alcohol in the vapor stream was computed from measurements of the mass fraction of alcohol in it using an infrared hydrocarbon sensor and extraction rate versus time then computed. Comparison between theory and data showed mass transfer to be a diffusion-limited process, except at sufficiently low scCO2 mass flow rates, where the mass transfer driving force was depleted due to the buildup of ethanol in the scCO2 stream flowing over the alcogel. It was necessary to utilize a concentration-dependent molecular diffusivity to properly pre dict drying kinetics. Panel II: New Materials and Materials Processing  137

Our presentation concludes with a discussion of outstanding needs which must be addressed to accelerate and reduce the cost of scCO2 drying. These include the development of experimentally-validated equations of state to compute the density of ethanol-CO2 and methanol-CO2 mixtures at process conditions. Once such data are available, installing a Coriolis flow meter in the effluent stream enables pressure, temperature and density to be simultaneously measured and, importantly, mass fraction of alcohol in the effluent to be computed. Then, the mass flow rate of alcohol leaving the extractor vessel equals solute mass fraction times effluent mass flow rate, and integrating this quantity over time enables the fraction of the total alcohol initially in the extractor to be monitored. A second outstanding need is measurement of concentration-dependent molecular diffusion coefficients in relevant systems at process conditions. It is suggested that the laser-induced grating method be used for this purpose because it is non-intrusive, has been successfully utilized to measure (Soret, thermal and mass) diffusion coefficients in supercritical water and, finally, unlike more common techniques such as those based on Taylor dispersion, it applies across the full range of solute concentrations. Finally, elucidation of the effects of “suction” and “swelling” in alcogels during drying due to the non-monotonic dependence of density on solute concentration need be resolved. Beyond the barrier in gas foaming: hollow polymeric micro- and nanoparticles BEyOND ThE BARRIER IN GAS FOAMING: hOLLOW POLyMERIC MICRO- AND NANOPARTICLES

s. orsi, E. Di Maio, p. A. netti, s. iannace Department of Chemical, Materials and production Engineering, University of Naples; P.le Tecchio 80, 80125, Naples, Italy; E-mail: [email protected] hollow polymeric nanostructures have huge scientific and industrial value. In particular, they are used for encapsulation of drugs, enzymes, proteins and genes in biomedical and pharmaceutical applications, for contrast agents for diagnostic as nanoreactors in chemistry and chemical engineering, as transducers and dielectrics in electronics. The current methods for the preparation of hollow polymeric nanostructures include: emulsion polymerization, suspension poly-merization, core-shell precursors, self-assembly, electrospraying and template-directed synthesis. The aim of this work is to introduce gas foaming as a suitable technology to produce hollows in micro- and nano-metric polymeric particles. Gas foaming is a common technique to generate hollows in bulk polymeric materials. Gas escape from super-saturated polymer/blowing agent solution is the driving force to bubble nucleation and growth. How- ever, gas escape also determines a gas loss through the external free surface, in particular in the 10-100 microns- thick layer of the polymeric matrix in contact with the external surface. This phenomenon essentially impedes the use of the gas foaming technology to produce hollow micro- and nano-metric particle, since the whole volume, essentially, is so close to the external surface that the dif-

 139 140  SFE 2013 | workshop on supercritical fluids and energy fusive path available to the gas within the induction time required for foaming. The proposed approach consists of retarding the gas loss from the free surface by embedding the particles in a removable barrier film. In doing so, we introduce an obstacle to mass transport that hinders gas loss from the free surface, at least within the time required for bubble nucleation, thereby allowing the phase separation within the particle. Barrier film-embedded polystyrene spheres were prepared by dispersing polystyrene spherical particles (500-50-5-0.5-0.2 µm in diameter) (Duke Scientific) dispersed in aqueous solutions poly(vinyl alcohol) (PVA) (Mowiol 40-88, Sigma-Aldrich, dried at room temperature for 72 h). Bare polystyrene spheres (without the barrier film) were also analysed and subjected to the following foaming process. For the production of foamed samples, a thermo regulated and pressurized cylinder having a volume of 0.3 L, (model BC-1, HiP Erie, US-PA) was used. The pressure discharge system consists of a discharge valve (model 15-71 NFB, HiP Erie, US-PA), an elec- tromechanical actuator (model 15-72 NFB TSR8, HiP Erie, US-PA) and an electro-valve. The pressure history was reg- istered by using a data acquisition system (DAQ PCI6036E, National Instruments, US-TX) and a pressure transducer (model P943, Schaevitz-Measurement Specialties, Hamp- ton, US-VA). In a typical experiment, the samples (barrier film-embedded polystyrene spheres and bare polystyrene spheres) were loaded into the vessel, pressurized with the blowing agent at 14 MPa and 100 °C for two hours and pressure quenched at 100 MPa/s. Particles were recovered by dissolving the PVA films in water at room temperature and washed centrifuging with water five times. To verify particle morphology, Focused Ion Beam-Scanning Electron Microscopy, Transmission Electron Microscopy and Con- focal Microscopy were used. Results show hollow particles Panel II: New Materials and Materials Processing  141 achieved with the use of a barrier film embedding the particles with diameters ranging from 50 microns to 200 nano- meters. The three order of magnitude spam in the particles dimension is an evidence of the high versatility of the proposed methodology. It is worth of note, furthermore, that PS bare particles (not embedded in PVA and collected on a permeable substrate) did not present any hollow, at all scales and experimental conditions. Finally, the proposed methodology has a high efficiency in terms of number of affected particles versus total number of particles. Among the many peculiar characteristics of the proposed methodology, it is simple, economic, environmentally friendly, robust, controllable and does not need any fine chemistry in polymer synthesis, emulsion or suspension preparation. Furthermore, it is suitable for a wide range of particle dimensions and shapes and allows achieving a large variety of possible pore structures. As a counterpart, however, the proposed methodology allows for a reduced control of the pore morphology and a subsequent sorting of particles could be necessary for specific applications. Perspectives on the use of Compressible Fluids in the Preparation and Processing of Polymer Systems for Drug Delivery Applications PERSPECTIVES ON ThE USE OF COMPRESSIBLE FLUIDS IN ThE PREPARATION AND PROCESSING OF POLyMER SySTEMS FOR DRUG DELIVERy APPLICATIONS

sandro R. p. da Rocha Wayne State University; 5050 Anthony Wayne Dr, 48085, Detroit, MI, USA; E-mail: [email protected]

Polymers find a wide range of potential applications in the biomedical industry, including as drug depots and carriers that may afford (a) protection to sensitive cargo, and strategies for the (b) controlled release and (c) targeting of therapeutic molecules to desired tissues, so as to enhance their efficacy and safety profiles. Supercritical or (more generally speaking) compressible fluid (SCF)-based technologies offer unique opportunities in terms of both polymer preparation and their processing with therapeutics for drug delivery applications.

Supercritical CO2 (scCO2) is of especial relevance as a polymer reaction and processing medium for drug delivery applications as it is non-toxic, non-flammable, relatively inert, and it can be sourced with high purity. scCO2 also has excellent mass and heat-transfer properties, and low surface energy. Moreover, the separation of scCO2 from the polymer product or drug-polymer system is facilitated as scCO2 can be reverted to the gaseous state by simple depressurization, thus eliminating energy intensive solvent removal steps that exist in processes involving conventional solvents. However, there are many challenges in using scCO2 for polymer preparation and processing with therapeutics, perhaps one of the most notable being the fact that while most monomers are soluble in scCO2, most

 143 144  SFE 2013 | workshop on supercritical fluids and energy polymers (and many small molecular weight therapeutics for that matter) are not. The good news is that the very same characteristics that challenge the use of scCO2 in polymer synthesis and polymer-drug processing, such as its poor solvent power, can actually be turned around and used as unique opportunities to develop groundbreaking technologies, both in terms of reaction medium and in the development of depots for drug delivery applications. For example, the fact that most polymers are insoluble in scCO2 is what makes scCO2 an excellent candidate medium for the development of innovative dispersion- based polymerization strategies. While most polymers are not soluble in scCO2, they can be plasticized by scCO2. This characteristic, along with its low viscosity and high diffusivity, points to scCO2 not only as a good solvent candidate, but as a unique solvent environment in dispersion polymerization. For example, scCO2 has been reported as a reaction medium that facilitates the access of growing chain ends and RAFT polymerization agents to monomers arriving into the growing latex, thus leading to a more efficient polymerization strategy [1]. Another interesting example of turning things/per- ceived disadvantages of scCO2 around comes from the fact that scCO2 is poorly miscible with water, and miscibility gaps can be found with organic solvents. These characteristics may provide opportunities for the development of novel emulsion-type polymerization and co-polymerization strategies, strategies which have been scantly explored. New opportunities in this area may also arise due to recent advancements in surfactant design for those interfaces, and better understanding of microemulsion formation in scCO2-based systems. Yet another example of potential contributions of scCO2-based technologies is in the preparation of polymer Panel II: New Materials and Materials Processing  145 drug depots. While most polymers have low solubility in scCO2, scCO2 itself can be used to plasticize polymer matrices for enhanced blending of other polymers [2] or impregnation with therapeutic molecules [3]. scCO2 can also be used to prepare polymer micro- and nanoparticles, and polymer fibers [4] with encapsulated drug solutes. scCO2 in this case may offer great advantages compared to traditional methods where the drug molecules may be water, organic solvent or heat labile, as for example protein therapeutics.

In spite of the potential advantages of scCO2 in the synthesis of polymeric materials and their processing for drug delivery applications, commercial processes involving such systems are very limited. The ability to promote the future utilization of scCO2-based technologies in this area hinges on our ability to continue to develop processes where scCO2 is not only a good alternative solvent, but the superior choice or the unique route for product development, along with stricter environmental laws, so as to tip the balance towards cleaner technologies.

References [1] J. Jennings, M. Beija, A.P. Richez, S.D. Cooper, P. E. Mignot, K. J. Thurecht et al., One-Pot Synthesis of Block Copolymers in Supercritical Carbon Dioxide: A Simple Versatile Route to Nanostructured Micro- particles, J. American Chemical Society, 134 (2012) 4772-81. [2] C. A. Kelly, A. Naylor, L. Illum, K. M. Shakesheff, S. M. Howdle, Su-

percritical CO2: A Clean and Low Temperature Approach to Blending PDLLA and PEG, Advanced Functional Materials, 22 (2012) 1684-91. [3] C. Gonzalez-Chomon, M. E. M. Braga, H. C. de Sousa, A. Concheiro, C. Alvarez-Lorenzo, Antifouling foldable acrylic IOLs loaded with nor- floxacin by aqueous soaking and by supercritical carbon dioxide technology, European J. Pharmaceutics and Biopharmaceutics, 82 (2012) 383-91. [4] L. Li, Z. Jiang, Q. Pan, T. Fang, Producing Polymer Fibers by Electro- spinning in Supercritical Fluids, J. Chem-Ny. (2013). Nanostructuration of polymer matrices by extrusion assisted with a supercritical fluid NANOSTRUCTURATION OF POLyMER MATRICES By ExTRUSION ASSISTED WITh A SUPERCRITICAL FLUID

Jacques fages, Elisabeth Rodier, Martial sauceau, nibal hijazi, nicolas Le Moigne, Jean-charles Benezet, Tamás vigh, Zsombor nagy, gyorgy Marosi École des Mines – CNRS – RAPSODEE research centre; Campus Jarlard, 81013, Albi, France; E-mail: [email protected]

In an eco-design and sustainable development perspective, many research works have recently been devoted to bio-sourced polymers. Manufacturing nano-composite with a polymeric matrix incorporating either an active pharmaceutical ingredient or a bio-filler may enlarge the field of applications of such structures towards several industrial areas: pharmaceuticals, detergents, fine chemicals, etc. In this lecture a few examples of nano-composite manufacturing process will be presented based on a supercritical carbon dioxide-aided extrusion process (acronym: XSCF). Pharmaceutical extrusion also known as HME (hot melt extrusion) is an efficient technology used to disperse drugs in a melt up to a true molecular solution of a pharmaceutical ingredient. Most of the applications describe the preparation of solid dispersions by HME either to increase the aqueous solubility and oral bioavailability of the active substance or to control its release. The mostly reported advantages of HME are: (a) avoidance of organic solvent; (b) reduction of processing steps (one-pot method); (c) elimination of the good compressibility requirement for the active ingredients and the excipients; (d) high level of drug content; (e) even dispersion of the drug throughout the matrix; and (f) improved bioavailability through drug

 147 148  SFE 2013 | workshop on supercritical fluids and energy solubilisation or molecular level dispersion in water soluble matrix. The injection of scCO2 in the extrusion process modifies the rheological properties of the polymer, and also, scCO2 acts as a blowing agent at the die exit. In the barrel of the extruder, the reduction of viscosity decreases the mechanical constraints and the operating temperature. At the die exit, the pressure drop induces a thermodynamic instability in the polymer matrix, generating a large number of bubbles, which can grow until the foam is ri- gidified when temperature drops below the glass transition temperature, Tg. The influence of several operating parameters, die geometry and temperature, polymer crystallinity, upstream pressure, addition of nanoparticles will be discussed. It could be concluded that the combination of extrusion with scCO2 allows processing relatively frag- ile or thermally sensitive molecules, like pharmaceutical molecules, without any residue in the final material. A few examples of XSCF implementation leading to significant improvements in drug dissolution kinetics will be presented. Extrusion is a widely used process to prepare nanocomposites with silicate-layered materials. Both melt intercalation and exfoliation can be obtained by XSCF. An example with PHB-HV and Cloisite, a natural montmoril- lonite clay, will be given. A new approach can be to generate nanoparticles from a biobased polymer to be used as a filler in a matrix. In our laboratory, we have been working with chitosan, a polysaccharide derived from shell- fish and some fungi. It has several properties including biodegradability, antibacterial and antifungal activities, making it a material of choice for applications in packaging and medical field. Particles were generated by a clas- sic SAS process (Supercritical Anti-Solvent), minimizing the use of organic solvents. scCO2 acts as an anti-solvent while chitosan is dissolved firstly in an acidic aqueous Panel II: New Materials and Materials Processing  149 solution to which ethanol has been added to improve the anti-solvent effect of the sc-CO2. Two coaxial capillaries allow the injection of the chitosan solution (the inner one) and CO2-sc (the outer one) in an autoclave filled with CO2 in which the particles are generated at 18 MPa and 306

K. The miscibility of the CO2 with ethanol and acetic acid, the solvent of chitosan, induces the reduction of the solvating power of the latter, which causes the crystallization of the particles. The sc-CO2 loaded with solvents is sent to three separators where gradual depressurization will separate the solvents and purify the CO2, that returns af- terwards to the autoclave. Using this process, we generated chitosan nanoparticles with an average size of 378 ± 13 nm and a positive mean zeta potential of 26.4 ± 0.2 mV. We have also developed a more innovative process, which led to nanoparticles of chitosan without any organic solvent. A further step, under present investigation, is to disperse these nanoparticles by extrusion in a biopolymer matrix, to produce a composite material for biomedical application.

Reference ff M. Sauceau, J. Fages, A. Common, C. Nikitine, E. Rodier, New challenges in polymer foaming: a review of extrusion processes assisted by supercritical carbon dioxide, Progress in Polymer Science, 36 (2011) 749-766. Opportunities in Fabrication of High Porosity Nanofibrous Structures OPPORTUNITIES IN FABRICATION OF hIGh POROSITy NANOFIBROUS STRUCTURES

carson Meredith School of Chemical & Biomolecular Engineering, Georgia Institute of Technology; 311 Ferst Dr., 30332-0100, Atlanta, GA, USA; E-mail: [email protected]

Nanofibrous structures with high surface area are appeal- ing to a wide range of practical applications in energy-related fields. These include white reflective surfaces for energy-efficient roofing, insulation, catalyst supports, sen- sors, filtration media and absorbents, lightweight structural materials and energy storage devices (supercapacitors and batteries). Current synthetic processes for fabricating low-defect, large-area nanofibrous structures with controllable fiber diameter, interconnectivity, and porosity suffer from a number of drawbacks. These include use of volatile organic solvents and scalability issues. Nature also produces intricate nanofibrous structures at ambient conditions, such as the dense high-strength Bouligand structure of lobster shells (composed of chitin and mineral) and wood (composed of cellulose) or the lightweight ultrathin cuticle of the Cyphochilus beetle. This cuticle contains a three-dimensional aperiodic network structure composed of chitin fibrils around 250 nm in diameter and containing about 30% air void volume, which results in both light weight and significant whiteness and reflectivity. The first part of this talk will review recent work in controlling the freeze- drying (sublimation) process to achieve fine, nanofibrous structures that mimic those produced in nature. The sec-

 151 152  SFE 2013 | workshop on supercritical fluids and energy ond part of this talk will take a forward-looking view of opportunities to utilize a relatively well-established technique, supercritical drying, to produce high porosity nanofibrous structures from a wide range of materials. Freeze drying has attracted intense interest as a general route to fabricate porous materials for a wide range of applications. Starting with a solution, emulsion, or dispersion, freezing causes solute or solids to be excluded by an advancing ice front into the interstitial spaces between ice crystals. Subsequent sublimation leads to porous structures. By controlling concentration and freezing direction, complex hierarchical morphologies are produced, including well- aligned channels, honeycombs, and brick-mortar-bridges (sheet-like structures that are oriented). Because of the large temperature gradients in common liquid-N2-based freeze drying, most studies report oriented structures resulting from fast, directional freezing. In contrast, non-directional freezing and solidification under higher freezing temperatures, required to produce elongated fiber structures, are not well explored. For example, structures that mimic the size and interconnectivity of the white beetle cuticle have not been achieved by freeze drying previously. To reproduce the aperiodic nanofiber structure, we show that freezing under higher temperature conditions (-20 °C) reduces the temperature gradient and allows non-directional freezing. Furthermore, because chitin dispersions readily form gels and liquid crystalline phases, we show that slowing the ice growth velocity allows encapsulation and preservation of networks of chitin fibers whose interconnectivity depend on the dispersion conditions just pri- or to freezing. Precursor solutions or dispersions of fibers can also be fabricated into controlled nanoarchitectures by self-assembly or electrospinning processes, but the solvent must then be removed while preserving the architec- Panel II: New Materials and Materials Processing  153 ture. There are drawbacks in terms of scalability and the use of volatile organic solvents, especially in spinning processes. Because of surface tension and interparticle at- traction, there is potential for contraction or even collapse of self-assembled structures during the drying step. The second part of this talk will survey opportunities to couple supercritical drying with existing self-assembly and spinning approaches to produce high porosity nanofibrous structures from a wide range of materials. Strengths and weaknesses, as well as obstacles to be overcome, will be discussed. Connections of structures to applications of relevance to energy savings, energy production and energy storage are drawn. Morphology Development and Pore Formation in Semi- Crystalline Polymers during

Crystallization in CO2 MORPhOLOGy DEVELOPMENT AND PORE FORMATION IN SEMI- CRySTALLINE POLyMERS DURING

CRySTALLIzATION IN CO2

Erdogan Kiran Department of Chemical Engineering; Virginia Tech, USA;

shinya Takahashi Kureha Corporation, Japan

Compressed or supercritical fluids such as carbon dioxide is of continuing interest and importance in various polymer modifications ranging from forming particles and fibers to foams and porous matrices. Even though polymers are typically not soluble in carbon dioxide, carbon dioxide can dissolve in a polymer, leading to enhanced chain mobility. The immediate consequence of increased chain mobility is the lowering of the glass transition temperature (Tg) and the delaying of the vitrification process, which by itself widens the temperature range in which modifications can be carried out. The lowering of the glass transition temperature is well documented for amorphous polymers. When semi-crystalline polymers are involved, with dissolution of carbon dioxide in the polymer matrix, if the melting temperature (Tm) is not crossed, increased chain mobility leads to lamellar thickening and to a recrystallized polymer which displays a higher melting temperature and higher level of crystallinity. This is also well documented in the literature. If however, a semi-crystalline polymer is exposed to carbon dioxide at temperatures where the polymer is in its molten state, and then its recrystallization is carried out by lowering the temperature in the presence of carbon dioxide, one observes lower crystallization temperatures compared

 155 156  SFE 2013 | workshop on supercritical fluids and energy to the ambient pressure crystallization temperature from the melt in the absence of carbon dioxide. Lowering of Tm is also a consequence of increased chain mobility and is well known. What is not as well-known is another phenomenon that occurs in crystallization from melt in the presence of a supercritical fluid like carbon dioxide. It is the development of unique morphologies displaying ring-banded spherulites. These arise from the helicoidal twisting of radial crystal lamellae and the edge-on and flat-on domains leading to the observation of ring-like morphologies when viewed under a cross-polarized optical microscope. The banded spherulites that develop consist of concentric ridges and valleys typically having around 100 nm vertical distances. The ridge area is constituted of the edge-on lamellae aligned to the radial direction of the spherulites while the valley area is formed by flat-on lamellae. A lesser known and explored phenomenon is the formation of pores in the crystallization process while these morphologies develop. Pore formation arises from exclusion of carbon dioxide from the crystal growth fronts and its accumulation in the amorphous regions in between the growing spherulitic domains, which eventually collapse and lead to non-spherical, oriented pores. In this presentation, using poly (3-hydroxybutyrate- co-3-hydroxyvalerate) (PHBV) as an example, we will address some important questions pertaining to the assessment of melting point depression, the influence of pressure on the progress of crystallization and the tendency of the system to develop banded spherulites, and on the influence of pressure on the pore formation. PHBV is a biodegradable semicrystalline polyester which is naturally synthesized by microorganisms which gives them their high degree of stereo-regularity and high purity. Low nucleation density due to the absence of the impurities allows uncommonly Panel II: New Materials and Materials Processing  157 large spherulites to grow during crystallization from the melt, which facilitate the observations of the developments of the unique morphologies. The presentation will emphasize the need for exploration of the lowering of the melting temperature and recrystallization of polymers from the melt in the presence of carbon dioxide with a new perspective. The unique morphologies that develop during crystallization in CO2 that lead to ring-banded spherulites containing pores in between needs to be explored with a fresh look as an approach to generate nano-porous structures. The pore formation arising from the exclusion of CO2 from the crystal growth front, and formation of the pores in the inter-crystalline amorphous region during crystallization raises new questions and potentially offers new opportunities with respect to the outcomes that can be expected in supercritical fluids which may not be limited to CO2.

PANEL PRESENTATIONS

Panel III: Green Chemistry and Sustainable Technology Modeling the volumetric and phase behavior of CO2 systems — successes and challenges MODELING ThE VOLUMETRIC AND

PhASE BEhAVIOR OF CO2 SySTEMS — SUCCESSES AND ChALLENGES

Amyn s. Teja School of & Biomolecular Engineering, Georgia Institute of Technology; Atlanta, GA 303320100, USA; E-mail: [email protected]

The volumetric and phase behavior of CO2 systems is of interest in a large number of green chemistry and sustainable technology applications, including polymer synthesis and nanocomposite fabrication, flue gas and natural gas processing, as well as drug encapsulation and nanoparticle precipitation. Both theory and experiment suggest that CO2 is able to interact with electron donating groups to form weak Lewis acid-base complexes. These electron donoracceptor or EDA complexes significantly affect the phase behavior of CO2 systems of interest in the applications mentioned above. In spite of their importance however, few thermodynamic models account for Lewis acid-base interactions explicitly. There is much interest, therefore, in thermodynamic models that incorporate weak specific interactions, especially for systems at high pressures that are typical of carbon dioxide processing. The more successful models for associating systems include versions of the Statistical Association Fluid The- ory (SAFT), and several lattice fluid equations of state such as those of Sanchez and Lacombe, and Panayiotou et al. Although these equations of state can be used for both phase and volumetric calculations, they generally require self and cross-association parameters that depend on tem-

 161 162  SFE 2013 | workshop on supercritical fluids and energy perature and/or molecular-weight. A significant amount of experimental information is therefore required for their use. Excess Gibbs energy models such as those of Painter, Coleman and co-workers, on the other hand, have been employed for describing specific chemical interactions such as hydrogen bonds. However, these models are not applicable to the calculation of volumetric properties. Re- cently, two lattice models (a Compressed Lattice activity coefficient model and an Associated Lattice Fluid equation of state model) have been used successfully to correlate phase equilibria and other properties in CO2 + polymer,

CO2 + cosolvent + polymer and CO2 + ionic liquid systems over a range of pressures and temperature. These models account explicitly for complex formation in the lattice fluid partition function, and therefore contain physically meaningful parameters that are independent of temperature or pressure. Moreover, it will be shown that in situ Attenuated Total Reflection Fourier Transform Infrared

(ATR FTIR) measurements or CO2 absorption data can be used to obtain one of the parameters in these models, with experimental phase equilibrium data being used to obtain the remaining adjustable parameter. The application of the Compressed Lattice activity coefficient model will be demonstrated by calculating both cloud points and sorption equilibria in CO2 + PVAc and

CO2 + PLGA systems using a single adjustable parameter. It will be shown that calculated equilibria are in good agreement with measured values confirming that the model is able to extrapolate phase equilibrium data over a range of pressures. It will also be shown that sorption equilibria in CO2 + PLGA systems can be predicted using information obtained from FTIR spectra and a single parameter obtained by fitting cloud point pressures in a reference system (CO2 + PLA in our case). This demonstrates Panel III: Green Chemistry and Sustainable Technology  163 that the model is capable of extrapolating information to systems that have common functional groups. The depression of the glass transition temperature in the CO2 + PLA system was also predicted without any additional parameters, demonstrating that the model can be used to predict other properties. However, the compressible lattice model is inherently incapable of predicting volumetric properties. This limitation has led to the development of the Associated Lattice Fluid Equation of State model that is able to calculate both phase equilibria and volumetric properties. The EOS contains two mixture parameters — the enthalpy of association ∆Ha and the equilibrium constant at a reference temperature K0 — which do not depend on temperature, pressure or molecular weight. The solubility of CO2 in a number of polymers was correlated over a wide range of temperatures and pressures using ∆Ha values from independent FTIR measurements and K0val- ues obtained by fitting solubility data. It is shown that the new model is able to correlate solubility data within experimental error (maximum AAD of about 4%). In addition, the extent of swelling of these polymers by CO2 can be predicted without any adjustable parameters. The ALF EOS therefore shows considerable promise in calculating both phase equilibrium and volumetric data of CO2 systems. Finally, the performance of these models in calculating phase equilibria and other properties of CO2 systems will be used to identify future directions and challenges in the modeling of such systems. Nanoparticle Synthesis and Processing using Tunable Fluids NANOPARTICLE SyNThESIS AND PROCESSING USING TUNABLE FLUIDS

christopher L. Kitchens Department of Chemical and Biomolecular Engineering, Clemson University, USA; E-mail: [email protected]

Advancements in nanotechnology have led to a widespread emergence of different techniques for nanoparticle synthesis and application. The size and shape dependent properties of nanomaterials motivate different synthesis methodologies that afford morphological control. For cases where morphology control is not afforded, monodispersed populations of nanomaterials can be obtained by post-synthesis fractionation based on size or shape. These fractionation techniques are typically very solvent and energy intensive as well as limited in scalability. A vital and often overlooked component in the nanotechnology field is the development of efficient, reduced-cost, and large-scale methods for nanoparticle synthesis and processing. In recent years, significant advancements have been made in nanomaterial synthesis, processing, and application using tunable fluids that provide promising alternatives to conventional methods. Tunable fluids are a unique class of fluids where the solvent’s thermophysical properties (eg. solvent strength, density, diffusivity, interfacial tension) can be tailored by controlling the system temperature and pressure. Examples of tunable fluids are supercritical fluids (SCFs), near-critical fluids (NCFs) and gas expanded liquids (GXLs). For the first two, the temperature and pressure of the system are either close to (NCFs) or above (SCFs)

 165 166  SFE 2013 | workshop on supercritical fluids and energy the solvent’s critical point. In this region, the solvent properties are intermittent between those of a liquid and of a gas; possessing the increased solvent strength and thermal conductivity of a liquid along with the diffusivity of a gas. Furthermore, the solvent is highly compressible under these conditions, which enables control of these properties by simply changing the pressure; hence the name tunable fluids. GXLs consist of a gas and liquid mixture at pressures below the vapor pressure of the gas phase. The tunable properties of GXLs rely on the high solubility of gasses in liquids where the composition of the mixture is controlled by the partial pressure of the gas phase. For example, CO2 expanded hexane at 49 bars of CO2 partial pressure is 80 mol % CO2 and exhibits a volume expansion of nearly three times the hexane volume at ambient pressure. At

58 bar and 25 °C, the liquid phase is 91.3 mol % CO2, thus a wide range of solvent properties can be achieved by simply changing the CO2 partial pressure over a moderate operating pressure range. The GXL liquid component can consist of virtually any non-aqueous solvent, which imparts a wide range of tunable fluid properties. Because the GXL consists of a liquid solvent and a dissolved gas, the thermophysical properties are again intermittent between the two but at a much reduced pressure. This presentation will review recent work in the synthesis and processing of metal and metal oxide nanoparticles in each of these tunable fluids; NCFs, SCFs, and GXLs. Specific topics will include:

Surfactant-mediated metal nanoparticle synthesis

in SC CO2 and CO2 expanded liquids where the tunable solvent properties govern the nanoparticle synthesis. Panel III: Green Chemistry and Sustainable Technology  167

Metal oxide nanoparticle synthesis in near critical and supercritical water.

Post-synthesis purification and size-selective fractionation of nanoparticles in GXLs.

Uniform deposition of nanoparticles into wide-area arrays using GXLs.

Development of a thermodynamic interaction energy model to predict nanoparticle dispersibility as a function of the tunable solvent properties.

Small angle neutron scattering (SANS) measurement of nanoparticle ligand shell thickness, solvation, and degree of surface coverage in GXLs.

For nanoparticle synthesis, the solvent properties influence the nanoparticle nucleation, growth, and stabilization, which results in control over the nanoparticle size and polydispersity. For polydispersed populations of nanomaterials, GXLs provide a novel medium for size and shape selective fractionation, where particle dispersibility is a function of the CO2 partial pressure. For example, dodec- anethiol-stabilized gold nanoparticles are easily dispersed in hexane. The progressive addition of CO2 to the hexane will induce size-selective precipitation where the largest nanoparticles precipitate at lower CO2 partial pressures and the smaller nanoparticles precipitate at higher pressures. This is akin to conventional liquid anti-solvent precipitation methods with the two notable exceptions: (1) following fractionation, the pressure can be released and all of the original solvents can be recovered, eliminating the significant amounts of solvent waste and (2) the increased nanoparticle diffusivity eliminates the need for centrifugation which reduces the energy requirement and facilitates the potential for large scale application. 168  SFE 2013 | workshop on supercritical fluids and energy

Many nanomaterial applications require uniform GREEN PROCESSES FOR HIGH deposition of nanoparticles onto a surface. Conventional ADDED-VALUE PRODUCTS solvent-based methods can result in non-uniformities from EXTRACTION FROM NATURAL interfacial drying effects or require slow volatilizing sol- SOURCES vents. For SCFs, spray applications are possible. For GXLs the CO2 pressure can be increased beyond the vapor pressure and then heated beyond the critical point before re- leasing the pressure, enabling critical point drying and preservation of the nanoscale structure. For each of these applications, a fundamental understanding of the un derlying thermodynamics behind the nanoparticle dis persibility facilitates our ability to produce well-defined nanomaterials for a diversity of applications in a sustainable manor.

References ff Hart et al., J. Supercritical Fluids, 79 (2013) 236-243. ff Von White II et al., Industrial & Engineering Chemical Research, 51(14) (2012) 5181-5189. ff Von White II et al., J. Physical Chemistry C, 114(39) (2010) 16285-16291. ff Anand et al., Industrial & Engineering Chemical Research, 47(3) (2007) 553-559. ff McLeod et al., Langmuir, 21(6) (2005) 2414-2418. ff McLeod et al., Nano Letters, 5(3) (2005) 461-465. ff Kitchens et al., Industrial & Engineering Chemical Research, 43(19) (2004) 6070-6081. GREEN PROCESSES FOR hIGh ADDED-VALUE PRODUCTS ExTRACTION FROM NATURAL SOURCES

E. ibáñez Instituto de Investigación en Ciencias de la Alimentación CIAL (CSIC-UAM); C/Nicolás Cabrera 9, Campus de Cantoblanco, 28049 Madrid, España; E-mail: elena@iﬁ .csic.es

At present, there is an enormous interest in trying to give new answers to one of the main societal challenges in our society: that is, sustainability. Sustainability can be understood as a rational way of improving processes to maximize production while minimizing the environmental impact or, in the words of the Environmental Protection Agency (EPA), “sustainability creates and maintains the conditions under which humans and nature can exist in productive harmony, that permit fulfilling the social, economic and other requirements of present and future generations”. Bearing this in mind, many aspects can be considered in this framework, ranging from the rational use of resources to the modern concept of biorefinery which, undoubtedly, may change our perception of the industrial processes in this century. Considering this framework, the production of valuable products from natural sources is of high interest since it can allow to consolidate the idea of sustainable processes. In the area of food science and nutrition, the finding of new bioactive compounds able to prevent or improve the health status of the individuals, mainly acting as food supplements or functional food ingredients, is of upmost importance nowadays. Considering the tremendous mar-

 169 170  SFE 2013 | workshop on supercritical fluids and energy ket value of the functional food industry, it is easy to understand the enormous interest in new compounds, extracts and products that, once its efficacy has been proved with scientific evidences, should be produced at large scale. A good example of this are, for instance, compounds such as antioxidants, associated to lower risk of certain diseases that are nowadays widespread in the developed countries, such as coronary heart diseases and cancer [1,2]. Although they have been investigated in the last years and some of them have provided with evidence about their effect, much more research is needed to prove their real efficacy in human beings. Undoubtedly, nature can be considered an unlimited source of bioactives and the search of new compounds with improved activities have ran parallel to the search for new natural sources. It is well known that there are many families of compounds with proved antioxidant activity, such as phenolic compounds, carotenoids and tocopherols, which are easily available in the vegetal kingdom. But at present there is a huge interest in the potential use of marine natural sources to obtain these bioactives, mainly considering their huge diversity, in terms of number of different species that might be potentially used, their sometimes unique chemical structures and their ability to work as natural bioreactors potentiat- ing the synthesis of valuable compounds depending on the cultivation conditions. Moreover, the biorefinery concept has been recently associated to algae as one of the most sustainable ways to improve the efficient use of algae biomass [3]. Moreover, researchers are facing new challenges in the development of new extraction processes to obtain valuable products from natural sources. Up to now, traditional extraction methods (mainly S-L extraction) have been used to extract bioactives; these methods have sev- Panel III: Green Chemistry and Sustainable Technology  171 eral drawbacks like they are time consuming, laborious, have low selectivity and/or low extraction yields. New challenges involve the development of fast, selective, efficient, sustainable, green (without using toxic organic solvents), with high yields and at lower cost. The techniques able to meet these requirements are, among others, those based on the use of compressed fluids such as supercritical fluid extraction (SFE), pressurized liquid extraction (PLE) and subcritical water extraction (SWE), which are among the more promising processes [4, 5]. Depending on the polarity of the green compressed fluid, different “green” or environmentally clean technologies can be used, as can be seen in Figure 1.

High polarity Medium Water polarity Pressurized solvents SWE, PLE Pressurized solvents

scCO2 + polar modifiers (EtOH) Low Gas Expanded Liquids polarity PLE, SFE, GXL

scCO2 Limonene PLE, SFE

Figure 1. Green solvents and environmentally friendly technologies used to extract high added-value products from natural sources

In this presentation, different examples will be shown, considering different raw materials such as plants, algae and food by-products and employing the above mentioned green technologies. With this approach we will try to demonstrate the possibility of tuning the extraction conditions depending on the target compound(s) and the raw material to achieve sustainable processes. 172  SFE 2013 | workshop on supercritical fluids and energy

Among other examples, some research works devel- Scientific production of oped in our laboratory will be presented dealing with the supercritical fluid technology direct extraction, using SFE (Supercritical Fluid Extraction), worldwide: role of academia of carotenoids (astaxanthin) from Neochloris oleoabundans biomass; the isolation, using gas expanded liquids (GXLs), of gamma-linolenic acid from Spirulina; the extraction of antioxidants from rosemary using integrated processes of extraction and particle formation (WEPO, Water Extrac tion and Particle formation On-line); and the use of LCA (Life Cycle Assessment) tool to evaluate the environmental impact of different green extraction processes (SFE, SWE, WEPO).

Acknowledgments This work was financed thanks to AGL2011-29857-C03-01 (Ministerio de Economía y Competitividad) and ALIBIRD, S2009/AGR-1469 (Comunidad de Madrid) projects.

References [1] A. Harris, S. Devaraj, I. Jialal, Oxidative stress, alpha-tocopherol thera- py, and atherosclerosis, Current Atherosclerosis Reports, 4(5) (2002) 373-380. [2] R. Brigelius-Flohe, F.J. Kelly, J. T. Salonen, J. Neuzil, J-M Zingg, A. Azzi, The European perspective on vitamin E: current knowledge and future research, The American J. Clinical Nutrition, 76(4) (2002) 703-716. [3] E. Ibañez, A. Cifuentes, Benefits of using algae as natural sources of functional ingredients, J. Science of Food and Agriculture, 93 (2013) 703-709. [4] M. B. King, T. R. Bott, Extraction of natural products using near-critical solvents; Blackie Academic & Professional, Glasgow, 1993. [5] J. A. Mendiola, M. Herrero, A. Cifuentes, E. Ibáñez, Use of compressed fluids for sample preparation: Food applications, J. Chromatography A, 1152(1-2) (2007) 234-246. SCIENTIFIC PRODUCTION OF SUPERCRITICAL FLUID TEChNOLOGy WORLDWIDE: ROLE OF ACADEMIA

socrates Quispe-condori School of Food Engineering, Universidad Peruana Unión; Alt. Km 19 Carretera Central, Ñaña, Lima, Peru; E-mail: [email protected]

Since benefits of supercritical fluids were recognized in the 70’s, extensive research have been carried out on their potential applications (supercritical fluid extraction, energy applications, analytical applications, supercritical water oxidation, supercritical fluid fractionation, supercritical fluid reactions, applications in material science, cleaning technology, fine particle production, encapsulation, foaming, green chemistry / engineering, sustainability / bioenergy / biomass, blending in supercritical media, polymerization / copolymerization, catalysis, material synthesis, drying, distillation, and crystallization) by several research groups. Although some of the technologies were implemented at industrial and commercial scales, scientific literature often presents new applications of supercritical fluids. Many reviews were presented about the progress of supercritical fluid technology in different areas. However, there are no references related to the analysis of scientific production in this technology. Scientific production is one of the critical factors for country development. Studies related to the production of information allow to evaluate the scientific activity and its development, identifying significant trends, characterizing representa- tive institutions, scientific working groups and research

 173 174  SFE 2013 | workshop on supercritical fluids and energy topics. Bibliometrics, when applying statistical methods, enables the analysis of scientific production from literature sources, determining the research activity in a quantitative way. During the last decades, bibliometrics has been applied in all knowledge areas, usually through descriptive reports. The objective of this work is to determine scientific production of the applications of supercritical fluids through a descriptive bibliometric analysis. The publication of articles, reviews, books and conference manuscripts from all countries were analyzed, giving special attention to the participation of academia in the development and diffusion of this technology, evaluating its production in terms of its international impact, and identifying the most productive scientific institutions. Scientific production was evaluated in the Scopus database (www.scopus.com). Sco- pus is the largest database of scientific literature, covering all areas of science, technology, medicine, social sciences and arts & humanities. Currently, it contains a record of approximately 50 million bibliographic references from 21000 titles and 5000 publishers. “Supercritical” term in Title field was used as search strategy in the database. The following bibliometric indicators of productivity were determined: Documents per year (from 1970 to September 2013), document type, scientific production by country, distribution for knowledge areas, number of papers per author, and publications for journals. Macro trends that guided the development of supercritical fluid technology in countries and institutions were identified. The total number of reported references in Scopus database were 26 923, distributed in Articles (77.20%), Con- ference Papers (15.86%), Reviews (4.42%), Articles in Press (0.54%), Books (0.23%) and Conference Review (0.23%). It is observed that United States (19.51%), China (16.68%), Panel III: Green Chemistry and Sustainable Technology  175

Japan (10.39%), Germany (4.70%) and France (4.38%) have the best indicators in terms of production of scientific articles. Development indicators of science in terms of publications in Latin America are farther away from the standards of countries with the highest scientific and technological development. Brazil (1.75%), Argentina (0.42%) and Colombia (0.16%) are the most productive. Regarding the field of application, it was observed that scientific production is oriented at Chemistry (22.23%), Chemical Engineering (16.28%), Engineering (12.10%), Materials Science (11.98%), Physics and Astronomy (10.28%), Ener- gy (6.20%), Environmental Science (4.97%), Biochemistry, Genetics and Molecular Biology (4.66%), Agricultural and Biological Sciences (3.36%), and Pharmacology, Toxicolo- gy and Pharmaceutics (2.15%). Main sources of diffusion of scientific production are Journal of Supercritical Fluids (14.67%), Industrial and Engineering Chemistry Research (5.24%), Journal of Chromatography A (4.43%), Fluid Phase Equilibria (3.67%) and Journal of Chemical and Engineer- ing Data (2.15%). Universities are the leading scientific productive institutions compared to the research centers. Institutions with highest scientific production are Tohoku University (1.36%), University of Tokyo (1.11%), Kyoto Uni- versity (0.99%), Tsinghua University (0.83%) and Zhejiang University (0.82%). The research center with highest scientific production is the National Institute of Advanced Industrial Science and Technology (1.11%). Modeling of supercritical carbon dioxide extraction of Jatropha (Jatropha curcas L.) seeds MODELING OF SUPERCRITICAL CARBON DIOxIDE ExTRACTION OF JATROPhA (JATRophA cuRcAs L.) SEEDS

suzana yusup, Vladan Mićić, yi herng chan Universiti Teknologi PETRONAS; Bandar Seri Iskandar, 31750, Tronoh, Perak, Malaysia; E-mail: [email protected]

This work investigates the extraction of Jatropha seeds utilizing supercritical carbon dioxide. The yield of the extraction increased with time and the extraction process can be clarified into slow and fast extraction region. In the modelling of the supercrital extraction process, Rever- chon-Sesti Ossea model and its modified form were used to compare with the experimental extraction yield and both models were found to be in good agreement with the process.

 177 Organocatalysis in supercritical CO2: a new efficient catalyst for Asymmetric Aldol Reactions ORGANOCATALySIS IN

SUPERCRITICAL CO2: A NEW EFFICIENT CATALyST FOR ASyMMETRIC ALDOL REACTIONS

Reinaldo Bazito Instituto de Química, Universidade de São Paulo (USP); Av. Prof. Lineu Prestes, 748-B8T, Sala 811, Cidade Universitária, 05508-000 São Paulo, SP, Brazil; E-mail: [email protected]

The enantiomers of a chiral compound have identical chemical properties but may present different biological action. There are many examples where one of the enantiomers is a very effective drug while the other is not as effective or may even be toxic. This has lead to extensive research on synthetic methodologies to produce a single enantiomer for target molecules containing stereogenic centers (enantioselective or asymmetric synthesis), specially using catalysis. Two major approaches have been used for asymetric synthesis: asymmetric catalysis, where the catalyst is usually a chiral transition metal complex; or biocatalysis, where the catalyst is an enzyme. A new approach, however, started to gain importance recently, the asymetric organocatalysis, where the catalyst is a small chiral organic molecule added to the reaction media in substoi- chiometric quantities. These molecules can be natural chiral compounds from the “chiral pool”, such as amino acids, alkaloids, sugars and so on, providing a greener approach to enantioselective synthesis. The Aldol condensation is a very important reaction in organic synthesis, with its asymmetric version being used to form a new carbon-carbon bound in an enantiose-

 179 180  SFE 2013 | workshop on supercritical fluids and energy lective way. Organocatalysis using chiral amino acids, especially L-proline, have been successfully employed for this reaction, providing a greener catalyst, but there are still some drawbacks, including a high E factor (high waste/ product ratio), mainly due to the use of organic solvents and the need to neutralize the base used in stoichiometric quantities, and long reaction times. New reaction media that could improve selectivity/yield, with shorter reaction times and reduced waste generation are being sought for. Supercritical carbon dioxide is one of these possible new reaction media, because of its unique properties: an environmentally benign solvent with accessible critical point (Tc = 304.2 K, Pc = 7.38 MPa), very good transport properties, unique phase behavior, among other interesting properties. The combination of this neoteric solvent with organocatalysis for the Aldol condensation reaction is very promising and was the subject of this work. Our group has recently studied a series of proline derivatives for the organocatalysis of Aldol type reactions in sc-CO2 or a combination of this solvent with an imidaz- ole-based ionic liquid (1-allyl-3-alkyl-imididazolium chlo- rides). The first Aldol reaction to be studied was the condensation reaction between acetone and 4-nitrobenzaldehyde, resulting in a β-hydroxy ketone (as the chiral addition product) and a α,β-unsaturated ketone (as the undesired achiral elimination product). The catalysts employed for this reaction were L-proline, used as a standard, and the following L-proline derivatives: (R)-thiazolidine-4-carboxylic acid (thio-L-proline); (2S,4R)-4-(dimethyl(phenyl)silyl) oxy-pyrrolidine-2-carboxylic acid (dimetilphenylsilyloxy-L- proline); (2S,4R)-4-(tert-butyldimethylsilyloxy)pyrrolidine- 2-carboxylic acid (t-butyl-dimetilsilyloxy-L-proline); (2R,3R, 4R,5R,6S)-2-(acetoxymethyl)-6-(pyrrolidine-2-carboxamido) Panel III: Green Chemistry and Sustainable Technology  181 tetrahydro-2H-pyran-3,4,5-triyl triacetate (peracetyl-glucos- amine-L-proline). The influence of pressure, temperature, presence of ionic liquid and type of catalyst were evaluated. The best results were obtained with one of the si- lylated catalysts, tert-butyldimethylsilyloxy-L-proline, with very good yields and enantiomeric excesses (e.e.) of the product, in shorter reaction times, especially in the presence of the ionic liquid. Yields around 54%, with enantiomeric excess around 79%, could be obtained in 2 h of reaction, at 150 bar and 40 oC. Another Aldol reaction that have been studied is the condensation reaction between cyclohexanone and 4-nitrobenzaldehyde, using as catalysts L-proline (as a standard), t-butyl-dimetilsilyloxy-L-proline, and a helicoidal polyacethylene containg L-proline groups, resulting in the chiral anti/syn addition product. The influence of reaction time and the presence of additives (acetic acid or ionic exchange resin) were investigated, for the same pressure and temperature used for the previous reaction (150 bar, 40 oC). Both catalysts were more effective than L-proline resulting in higher yields and enantiomeric excesses in shorter times. The best results were obtained with the tert-butyldimethylsilyloxy-L-proline catalyst, using ion exchange resin, with an isolated yield of 71% and an e.e. of 91% (for the anti product). The proline derivatives were effective organocata- lysts for the Aldol reactions in sc-CO2, specially the silylat- ed derivative, presenting shorter reactions times than in organic solvents and good yields and enantiomeric excesses. Phytochemical Production from Biomass using Pressurized Fluids PhyTOChEMICAL PRODUCTION FROM BIOMASS USING PRESSURIzED FLUIDS

Marleny D. A. saldaña Department of Agricultural, Food and Nutritional Science, University of Alberta; Edmonton, Alberta, T6G 2P5, Canada; E-mail: [email protected]

Pressurized fluids, such as subcritical water, pressurized aqueous ethanol and supercritical CO2 (scCO2) are considered green and environmentally friendly solvents that can be used for production of phytochemicals from a variety of Canadian biomasses as well as for various reactions. Phytochemicals, such as phenolic acids are found in various biomasses as hydroxybenzoic and hydroxycinnamic acids. These compounds have antioxidant and antimicrobial activities and their consumption have been correlated with a lower incidence of cancer, heart disease, and diabetes. Carbohydrates are also considered important phytochemicals that can be used in a number of food, pharmaceutical and fuel applications. Research in my laboratory has focused on solubility determination of selected phenolic acids and sugar compounds in pressurized water as well as the use of pressurized fluids to obtain these phenolics and carbohydrates from biomasses, such as potato peel, lentil husk, and barley hull, among others to later be used in various applications. For solubility of selected phenolic acids and selected sugars in pressurized water, experimental data were obtained at pressures of 15-120 bar and temperatures of 100-180˚C using a dynamic flow high pressure system. The results obtained showed

 183 184  SFE 2013 | workshop on supercritical fluids and energy that the solubility of sugars (glucose and lactose) in pressurized water increase with an increase in temperature. However, with the increase of pressure from 15 to 120 bar, the solubility of both sugars in pressurized water decreased. For selected phenolic acids, solubility was affected by temperature. Dissolution of selected phenolic acids in pressurized water increase, remain stable (gallic acid) or decreased (3-4-hydroxyphenyl propionic acid and 4-hydroxybenzoic acid) with an increase of temperature. Pres- sure influenced aqueous solubility of gallic acid from 100 to 150˚C, but had no effect on the solubility of the other phenolic acids selected in the temperature interval studied. Experiments of phenolics and carbohydrates removal of selected biomasses using pressurized fluids were performed using a dynamic flow high pressure system at different temperatures ranging from 100 to 260˚C, pressures up to 200 bar and times up to 180 min. Other variables evaluated for selected biomass systems were static holding time and pH. Then, experiments of enzymatic synthesis of selected phenolic compounds in oil in scCO2 media were performed in a laboratory-scale supercritical fluid system at different temperatures ranging from 40 to 80˚C, pressures from 4 to 350 bar and time up to 53 h. In addition, the use of selected phenolic compounds in milk was evaluated at temperatures of 60-120˚C, pressures of 1000-6000 bar and times up to 15 min. Extracts and residues obtained after biomass treatment using pressurized fluids were evaluated for their individual concentrations of phenolic and carbohydrate compounds, total phenolic and carbohydrate contents, and antioxidant activity. Results indicated that the total phenolic and carbohydrate contents and antioxidant activity increased with temperature. The highest total carbohydrates, total phenolics, and total antioxidant activity of each biomass were obtained at optimized con- Panel III: Green Chemistry and Sustainable Technology  185 ditions of pressure, temperature and static holding time using pressurized fluids. For example, the highest carbohydrate extraction (576.1±19.1 mg/g hull) from barley hull was obtained using pressurized aqueous ethanol with low ethanol concentration (12%, v/v), but this pressurized fluid was not the best for phenolics removal. For the applications, results have shown that scCO2 is a promising green solvent for the enzymatic synthesis of phenolic lipids. In addition, the use of selected phenolic acids in milk retained valuable components while inactivating spores (Bacillus amyloliquefaciens) and the alkaline phosphatase enzyme using high pressure processing assisted by temperature. Phytochemical production from selected biomasses using pressurized fluids and its uses in reactive system applications were demonstrated.

PANEL PRESENTATIONS

Panel IV: SCFs as Working Fluids / Process Technology and Design Synthesis and Powder Generation of Powder Coatings using supercritical Carbon Dioxide SyNThESIS AND POWDER GENERATION OF POwDER COATINGS USING SUPERCRITICAL CARBON DIOxIDE

i. Bochon, M. petermann University Bochum; Universitaetsstr. 150, 44801, Bochum, NRW, Germany; E-mail: [email protected]

The use of powder coatings is a promising way to reduce organic solvents emission, as the application of such coatings is completely emission free. Unfortunately the synthesis of powder coating components is classically made with organic solvents, which is leading to emissions in the manufacturing step. Powder coatings consist of two main components, a binder and a hardener, which can be cross- linked via a chemical reaction, induced by heat or radia- tion. Beside these polymeric main components, additives like pigments, fillers, degassing agents etc. have to be added. To manufacture powder coatings different industrial steps are necessary. First the polymers have to be synthesized and granulates have to be formed. In a second step the polymers and the other components have to be homogenized in drum mixers. This mixture is melted, rolled to a plate, solidified and later broken into flakes. These flakes have to be ground to the final powder coatings. For this step, air-jet mills are used to gain powders with average particles sizes of 30-40 micrometers. Overall the classical powder coating manufacturing process is time, energy and cost intensive and additional solvent emissions have to be accepted during polymer synthesis. The aim of this work is to substitute the classical multi-step process with a single continuous process, using supercritical car-

 189 190  SFE 2013 | workshop on supercritical fluids and energy bon dioxide as auxiliary media. In a first step the synthesis of the polymer is made in supercritical CO2 and, by adjusting the process parameters can be done in a single phase regime. This is leading to high space-time yields. The synthesis of a powder coating binder in supercritical

CO2 was first published by Beuermann et al. [1,2] In a second step, without depressurization, the additional components of a powder coating have to be added — mainly the hardener component. A surplus of carbon dioxide is leading to a further reduction of the polymer viscosity and is easing the spray of such mixtures. To form the final powder coating, the so called PGSS (particles from gas saturated solutions) process is used [3]. In this process, a gas saturated mixture is expanded via a nozzle into a spray tower. The pre-expansion pressure is lying in the area of 20 MPa and the pre-expansion temperature is slightly above the melting point of the components. During the expansion, the dissolved gas is set free and is leading to a fine droplet formation. Additionally, the gas cools down, caused by the Joule-Thomson effect. Due to the cooling, the droplets solidify and a powder coating is formed. The expansion can be additionally used for the cleaning of the polymers. Residue monomers, left over after the reaction can be stripped away by the expanding gas. The supercritical fluid process is characterized by a single step design and is leading to no solvent emission. The contribution will first illustrate the optimization of the polymer reaction of the binder component in supercritical fluids. These experiments were carried out first in a batch reactor and later in a continuous tubular reactor. In a second part the continuous single step process will be illustrated. This plant consists of the tubular reactor and a PGSS plant for the particle generation. The reactions carried out in compressed CO2 are characterized by high yields of 80-90%, Panel IV: SCFs as Working Fluids / Process Technology and Design  191 short reaction times of about 20 minutes and a small polydispersity of PDI ≤ 2 of the synthesized polymer. The experiments show that the targeted average molecular weight of Mn ≈ 2500 g/mol can be reached in presence of the compressed gas. The contribution will end with ready-made powder coatings, gained with a plant, which is combining the tubular reactor with the expansion step of the PGSS plant and is leading to particle systems which have mean particle sizes, suitable for powder coating applications.

References [1] S. Beuermann, M. Buback, C. Isemer, A. Wahl, Homogeneous free-

radical polymerization of styrene in supercritical CO2, Macromolecular Rapid Communications, 20(1) (1999) 26-32. [2] S. Beuermann, M. Buback, M. Jürgens, Free-radical terpolymerization of styrene and the two methacrylates in homogeneous phase con-

taining supercritical CO2, Industrial Engineering Chemistry & Research, 42(25) (2003) 6338-6342. [3] E. Weidner, M. Petermann, K. Blatter, V. Rekowski, Manufacture of Powder Coatings by Spraying of Gas-Enriched Melts, Chemical Engi- neering & Technology, Wiley-VCH, Weinheim, (24) (2001) 529-533. Supercritical CO2 as working fluid in the Natural Gas Industry SUPERCRITICAL CO2 AS WORKING FLUID IN ThE NATURAL GAS INDUSTRy

christopher g. spilsbury BG Group, Thames Valley Park; RG6 1PT, Reading, Berkshire, UK; E-mail: [email protected]

The Natural Gas industry represents a potential opportunity in the application of supercritical carbon dioxide as a working fluid for the efficient transport of natural gas. This is the subject of this perspective. The goal of many companies such as the BG Group is to reduce the carbon footprint of business operations and improve efficiency. BG Group is seeking to improve efficiency of its operations at a rate of 2% per annum. The natural gas industry makes extensive use of large gas compressors, some as large as 50 MW and more. These gas compressors are used for many duties including pipeline gas compressors and refrigerant gas compressors used in gas liquefaction plants (LNG). Many of these gas compressors are driven by gas turbines. The industry also uses gas turbine driven gen- erator sets, often to generate the electricity used on remote gas production and gas processing facilities. The BG Group itself has more than 100 gas turbine driven machines distributed across it assets. Gas turbine driven equipment is used in both an onshore and offshore environment. Many of these gas turbines are installed as simple open cycles without waste heat recovery. To date this has been for many reasons including how to utilise the exhaust waste heat effectively and in some case space and weight constraints. Supercritical CO2 applied to energy recovery from

 193 194  SFE 2013 | workshop on supercritical fluids and energy these gas turbine exhausts has great potential. A super- Hydrocarbon group separation critical CO brayton or rankine cycle for energy recovery 2 using supercritical CO2: The could recover the heat to electrical energy or motive pow- last 20 years and the future at er for the gas compressors. These cycles are potentially PETROBRAS R&D Center as efficient as steam cycles, simpler than steam or organic rankine cycles, use a safe working fluid and have potentially the lowest space requirement. There is potential to utilise supercritical CO2 as a component in providing highly efficient local solution for gas industry driven equipment without the need for extensive power and heat distribution systems with their associated energy losses. For those gas turbine in the BG Group there is potential to recover over 1 GW of power. There is a significant role that supercritical CO2 as working fluid could play in improving the industry efficiency. With typical machine duties in the range of 5 to 50 MW the industry utilises of machines of an ideal size to develop and demonstrate supercritical CO2 technology. The gas industry continues to grow with investment in new pipelines, compression systems and gas liquefaction facilities providing opportunity for investment in heat recovery using supercritical CO2 as working fluid. There are technical challenges for this technology in the size range being considered, particularly in the CO2 expansion turbine design. The compactness of supercritical

CO2 may make this the future technology of choice for energy recovery on offshore installations to make these installations the most energy efficient. It is very possible that mechanical work derived from the supercritical CO2 turbines may be integrated to supplement the mechanical power of the gas turbine prime mover in one highly efficient package. One day we might see a mechanical driv- er package with a combined efficiency of over 55%. The natural gas industry has an opportunity to play a significant role in the development and implementation of supercritical CO2 power systems. hyDROCARBON GROUP SEPARATION

USING SUPERCRITICAL CO2: ThE LAST 20 yEARS AND ThE FUTURE AT PETROBRAS R&D CENTER

flávio c. Albuquerque, Arthur de Lemos Scofi eld, Marcos vinícius Riscado cabral CENPES – PETROBRAS R&D Center; Av. Horácio de Macedo, 950, Cidade Universitária, 21941-915, Rio de Janeiro, RJ, Brazil; E-mail: [email protected]

M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil

Fossil fuels are complex mixtures constituted by hydrocarbons and N,S,O-compounds as contaminants, with a wide distillation range. The complete separation of these mixtures in the individual constituents is feasible only for the lighter fractions, using high resolution analytical techniques, like 1D- and, more recently, 2D-gas chromatography. To analyze the whole crude oil or its heavier fractions, group separation according to the chemical nature of their components is usually required. The determination of hydrocarbon families, such as saturated hydrocarbons, olefins, diolefins, and hidrocarbons according to the number of aromatic rings is essential for the petroleum industry in many situations. Although fairly simple, considering the huge number of components, it provides enough information to evaluate quality of crude oil or fuels, to infer about their stability, or to optimize refining processes and catalysts. Unfortunately, most of these analyses, usually performed by normal phase liquid chromatography or solid phase extraction, suffer with different drawbacks. To cir-

 195 196  SFE 2013 | workshop on supercritical fluids and energy cumvent the lack of a universal detector for liquid chromatography, separations have sometimes to be performed through preparative procedures, which are often lengthy and lead to loss of lighter components. The choice of analytical-scale liquid chromatography with the refraction index detector is restricted to the analysis of narrow distillation cuts or products, due to differences in the response factors of the components. In the mid of 80’s there was a rebirth of supercritical fluid chromatography (SFC), which promised faster and more efficient separations than high-performance liquid chromatography. By the beginning of 90’s, ASTM approved D 5186 standard, for determination of mononuclear and polynuclear aromatic hydrocarbon contents in diesel fuels by SFC. The usage of polar stationary phase in combination with CO2, as mobile phase, allowed separations by hydrocarbon groups with flame ionization detector (FID). CENPES / PETROBRAS purchased its first commercial supercritical fluid chromatograph in 1995, and since then it has extended the application of SFC to all hydrocarbon liquid streams produced in a petroleum refinery. CENPES has also set up methods to determine other hydrocarbon groups, like olefins and diolefins in light and middle hydrocarbon distillates. Although it is generally assumed that olefins are absent from petroleum, this compounds are formed during catalytic or thermal crack- ing of petroleum heavy fractions. These hydrocarbons can either contribute to increase octane number of gasoline fuels, or they also play an important role in gum and solids formation. ASTM has approved another standard test method (D 6550) to determine total olefins in gasoline fuels, also with CO2 as mobile phase and FID detection, but adding a silver-impregnated column for selective trapping of unsaturated components, and two 6-port, 2-position Panel IV: SCFs as Working Fluids / Process Technology and Design  197 valves, to change flow path of the mobile phase and backflush the olefinic components. A different approach was adopted in CENPES, in which a small, home-made, highly silver-impregnated trap is used. In addition, a different sequence of timed events for valves actuation during the analysis was established. These changes make possible to determine not only olefins, but also saturated and aromatic hydrocarbons by ring number in a single chromatographic run. While ASTM D 6550 is restricted to the analysis of gasoline fuels, CENPES’ method can be applied to the entire range of atmospheric pressure distilled fractions. Conjugated diolefins constitute a small fraction of the total olefins and are strongly related to the instability of fuels. An analytical method was developed to determine these substances, again using SFC with conditions similar to the previous ones, except the detection mode: instead of FID, UV detection at 240 nm was chosen. Non-aromatic and aromatic compounds are chromatographically separated and conjugated diolefins are the only substances belonging the non-aromatic peak that absorb UV in this wavelength. The method is usually applied to petroleum light distillates (i.e. naphtha fractions), in which most of the conjugated diolefins concentrate. Sulfur-containing components can also be grouped and determined by SFC coupled with sulfur-selective che- miluminescence detector. Group separation of fossil fuels by preparative SFC is under investigation to provide greener and faster separations, while allowing the isolation of fractions for further chemical characterization. Cross Industry Integration for Power Plants of the Future and Supercritical Fluids CROSS INDUSTRy INTEGRATION FOR POWER PLANTS OF ThE FUTURE AND SUPERCRITICAL FLUIDS

Aydin K. sunol University of South Florida; Tampa FL 33620, USA; E-mail: [email protected]

Desire for a sustainable world, does should, and will continue to demand a critical look at the way we meet our basic needs beyond the ways we are used to even in the highly capital intensive basic industries which are known to be very risk averse with demands and incentives for disruptive changes are incremental and where cross industry fertilization is only blossoming. This presentation will provide a forum for discussion of supercritical fluid cycles, their current utilization and potential impact with relaxation of cross industry barriers to entry. Specific examples will include biomass or coal to liquids plant integration power plants, solar and nuclear power implications, sequestering implications and integration, and natural product processing and power integration, and urea/ammonia production in integrated gasification combined cycle power plants. One of the examples is elaborated in the abstract. Coal to liquid conversion, for either liquid fuel or chemical products, and power go back thousands of years. Indirect processes that utilize gasification and subsequent gas to liquids conversion using Fischer Tropsch type synthesis seems be the choice in expense of direct liquefaction paths that involve hydrogenation of coal using hydrogen and/or a solvent that itself can donate hydrogen to coal.

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Due to technological and environmental challenges associated with direct routes, less efficient indirect routes attracted more interest, in terms of development and commercial effort. A noteworthy exception to the choice is Shenua plant in Northern China that produces/processes millions tons/year of coal to liquid fuels using direct routes. The world’s largest coal to liquids plant employs direct route at a cost of about $45-$65/barrel. One interesting direct coal conversion process was National Coal Board’s (UK) Supercritical Gas Extraction route using typically Toluene as a solvent. Although percent extracts were lower (around 40-45%), the process yielded hydrogen rich extract and residue that was as reactive as the parent coal. The extracts were less condensed and therefore a lot more amenable to efficient hydrocracking. The cumbersome solid-liquid separation train was eliminated while solvent recovery and environmental issues were minimized. The author was first to employ Su- percritical Water successfully as a solvent for extraction [1] and similar results were independently reported later (e.g. Despande et. al. [2]). Water can indeed solubilize hydrocarbons at supercritical conditions. We also proposed to integrate direct and indirect coal liquefaction synergistically benefiting from extract residues that have the reactivity and energy content of the parent coal. Power plants that utilize supercritical water have efficiencies around 45% and have been around for some time. Thus, the technical know-how for working with supercritical water does exist. Power plants that utilize supercritical water can be a source of solvent for Supercritical Coal extraction plants. The existent coal feed preparation and post environmental clean-up facilities are also prem- ises that make such an integrated technology feasible. These facilities also include water treatment that benefits Panel IV: SCFs as Working Fluids / Process Technology and Design  201 the solvent extraction cause. It is important to point out that corrosion issues associated with supercritical water oxidation of waste are not applicable to use of supercritical water as coal solvent due to non-oxidative nature. Carbon dioxide capture and sequestering in power plants as well as coal to liquid plants offer synergistic integration opportunities as well. For instance, homogenous catalysts that can be used residue gasification, can be used in capture carbon dioxide. Another possibility is to co-production urea, a fertilizer. Features of holistic piloting and modeling programs that aim to develop integrated conceptual designs of plant that synergistically combines supercritical cycles of power plants with chemical production benefit from use of today’s computational tools such as CFD calculations, flowsheet simulators and mathematical programming techniques such as Mixed Integer (Non) Linear Programming as elaborated by Baliban [3]. The economics of the integrated concept is far more favorable than any of its stand-alone components. Such power plants not only provide feedstock, raw material and catalyst, but can utilize the resulting clean fuels and incorporate sequestering. The proposed integrated facilities do also share environmental and gas treatment facilitates. The approaches taken do need to incorporate life cycle consideration and environmental impact.

References [1] A. K. Sunol, Supercritical Extraction of Coal, PhD Dissertation, 1982. [2] G. V. Despande, G.D. Holder, A. A. Bishop, J. Gopal, I. Wender, Ex- traction of Coal with Supercritical Water, Fuel, 63(7) (1984) 956-960. [3] R. C. Baliban, J. A. Elia, C. A. Floudas, Optimization framework for the simultaneous process synthesis, heat and power integration of a thermochemical hybrid biomass, coal, and natural gas facility, Computers & Chemical Engineering, 35(9) (2011) 1647-1690.

Supercritical water gasification and its developments in China SUPERCRITICAL wATER GASIFICATION AND ITS DEVELOPMENTS IN ChINA

Liejin guo State Key Lab of Multiphase Flow in Power Engineering (SKLMF), Xi’an Jiaotong University (XJTU); Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China; E-mail: [email protected]

Supercritical water provides an excellent reaction medium for clean and efficient way in energy conversion. Since 1997, a series of studies on hydrogen production from supercritical water gasification have been conducted by the group of State Key Lab of Multiphase Flow in Power En- gineering (SKLMF) in Xi’an Jiaotong University (XJTU).

ThEORETICAL RESULTS Chemical reaction equilibrium analysis is investigated by Gibbs free energy minimization method. The simulation result confirms the experimental result that as reaction temperature increases, the hydrogen yield increases. However, as the temperature is above about 600 ºC, the gas yield is almost constant. That is to say, 600 ºC is enough and further increase of temperature is not necessary. As for the solar cavity-receiver, the exergy peaks at about 600 ºC considering the heat loss from the solar cavity-receiver. So, it sounds a good idea to couple supercritical water gasification with solar concentrating system.

Separating CO2 is the basic for the CO2 emission reduction. High pressure separator is used for separating carbon dioxide with other gaseous products. According to phase equilibrium analysis, the optimal operating condition for

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CO2 capture is obtained. The study on gasification kinetics model was proposed and it focuses on the main gaseous products. CFD model is developed for the reactor optimization and amplification. The above achievement will be published later. A novel thermodynamics cycle power generation system is proposed by SKLMP which is based on coal gasification in supercritical water and multi-staged steam turbine reheated by hydrogen combustion. It is characterized by its high coal-electricity efficiency, net CO2 emission and no pollutants.

Experimental device A quartz tube reaction system with the reactor diameter of 1.5 mm and length of 200 mm was established to obtain the non-catalytic reaction kinetics. High throughput autoclaves made of Hastelloy C276 and Inconel 625 were established for the catalyst screening and the reaction mechanism study. A continuous pipe-flow system for supercritical water gasification was designed for the temperature up to 800 ºC and the pressure up to 30 MPa. A supercritical water fluidized bed system was developed to solve the blocking problem and it was designed for the temperature up to 923 K and the pressure up to 30 MPa. It is proved from the point of view of thermal dynamics that supercritical water gasification process driven by concentrating solar energy may achieve high efficiency for hydrogen production. So the first supercritical water gasification device driven by concentrated solar energy was constructed. Hydrodynamics of a supercritical water fluidized bed was conducted and a predicting correlation for the minimum fluidization velocity in a supercritical water fluidized bed was obtained based on the experimental results of a fixed bed and the fluidized bed pressure drop. Panel IV: SCFs as Working Fluids / Process Technology and Design  205

Experimental regularity The feedstock covers various agricultural biomass (such as corn cob), liquid waste (such as black liquor, pharmaceutical wastewater), solid wastes (such as municipal sludge), coal (Yimin lignite, Hongliulin bituminous etc.) and their model compound. The complete gasification operation condition for each feedstock is obtained. Higher temperature and oxidative equivalent ratio favors complete gasification. Lignite has highest hydrogen fraction and yield. Hydrogen gasification efficiency can be as high as more than two hundred percent. It means that the hydrogen we obtained is two times higher than the hydrogen originally in the coal. The influence of pressure is not significant in the experimental scale we investigated; low concentration favors complete gasification; particles more than 100 μm needs on more grinding. The co-gasification characteristics are investigated and Synergistic effect is found. Organic wastes water can be used as the feedstock of water-coal slurry. So hydrogen production can be combined with waste treatment. Corrosion is an inevitable topic for supercritical water gasification. Intergranular corrosion may occur in the reactor inner wall, which can be restrained by controlling the reaction condition or conducting corrosion protection treatment such as aluminizing.

Catalyst Screening The catalytic effect of K2CO3 and Raney-Ni was investigated for gasification in supercritical water. It is proved that in pipe flow reactor K2CO3 has better catalytic effect due to the better dispersion. We also conducted the study of catalyst screening, for the active with high hydrothermal stability and strong carbon deposition resistance in the process of supercritical water gasification. Nickel -Magnesium -Al catalyst has been proved to be a promising catalyst for supercritical water gasification. 206  SFE 2013 | workshop on supercritical fluids and energy

Demonstration plant ENZYME TREATMENT Based on the experimental regular and theoretical AND INACTIVATION OF result mentioned above, a demonstration plant is estab- MICROORGANISMS IN lished in the Ningxia Hui Autonomous Region. The slurry COMPRESSED FLUID MEDIA treatment is more than 1 ton per hour, and the maximal concentrating power is 163 kW. The demonstration plant verifies the feasibility of large-scale application of the technology. The details for the demonstration plant will be published later. The demonstration plant paves the way for the industrial application of supercritical water gasification and it shows bright future of large-scale application. ENzyME TREATMENT AND INACTIVATION OF MICROORGANISMS IN COMPRESSED FLUID MEDIA

José vladimir de oliveira Department of Chemical and Food Engineering, Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil; E-mail: [email protected]

This talk comprises a brief review of the state of the art regarding enzyme treatment in compressed fluids towards its utilization in enzyme-catalyzed reactions of great interest for chemical and food industries. In particular, great attention is devoted to oil modification, as well as production of GOS and FOS using supercritical carbon dioxide, propane, n-butane and liquefied petroleum (LPG) gas as solvent media. Enzyme behavior in compressed fluid medium is discussed in terms of the effects of system pressure and temperature, exposure time and depressurization rate. The behavior of free, immobilized and enzyme in solution are investigated in compressed fluid medium and characterized by several analytical techniques (SEM, XRD, FTIR, DSC, TGA, etc.). A variety of high-pressure equipment is shown to be useful for enzyme treatment experiments, depending on the enzyme form, varying the temperature from 35 to 75 ºC, in the pressure range of 10-280 bar, exposure times from 1 to 6 hand adopting distinct decompression rates (compression/expansion cycles). Results showed that, in general, activity losses are verified for all enzymes in carbon dioxide, while the use of propane, n-butane and LPG promoted enhancements of enzyme activity and stability. In general, within the range studied, temperature

 207 208  SFE 2013 | workshop on supercritical fluids and energy and exposure times affected positively enzyme activity Reactor Design in Supercritical while the decompression rates did not demonstrate to be Continuous Flow Systems a relevant variable. Additionally, the use of supercritical carbon dioxide (scCO2) treatment as an innovative preservation method to inactivate pathogenic microorganisms in food products is considered. The effects of scCO2 treatment on the inactivation of Escherichia coli, Listeria mono- cytogenes and the microbial load of Vibrio parahaemolyticus in fresh oysters are considered. The effects of exposure time, scCO2/product mass ratio, temperature, number of pressure cycles, system pressures from 80 bar up to 200 bar and also pressurization and depressurization rates on the microbial inactivation is taking into account. A storage study is also carried out on the treated and untreated product to monitor microbial growth. It is shown that treatment with scCO2 may be a potential technique to reduce microbial growth, which may lead to product’s safety enhancement with possibly increasing shelf life. REACTOR DESIGN IN SUPERCRITICAL CONTINUOUS FLOW SySTEMS

Thomas huddle University of Nottingham; University Park, NG7 2RD, Nottingham, Nottinghamshire, UK; E-mail: [email protected]

This presentation addresses the design of supercritical continuous flow systems, which can be applied to a large number of processes, but focuses mainly on their application to hydrothermal and solvothermal synthesis of metal and metal oxide nanoparticles. Continuous flow systems offer several advantages over traditional batch methods, and supercritical fluid processing is no exception. On larger scales, continuous flow systems can offer higher throughput, while minimising the volume of fluid subject to the often extreme reaction conditions at any one time. A major benefit of working with continuous flow systems at an analytical scale is the ability to rapidly screen a large range of reaction conditions, which is generally not possible when working in batch. Several system components are neces- sitated in supercritical continuous flow designs, but undoubtedly the most important feature is the reactor — the volume in which the desired process occurs. There are several important considerations related to reactor design in continuous flow systems, especially with regard to residence time. Residence time (time the flow experiences reaction conditions) is critical in relation to the activation energies for a process, and is affected by distribution in flow paths, stagnant zones, and the rates of heating and cooling; these are factors which are themselves dependent

 209 210  SFE 2013 | workshop on supercritical fluids and energy on mixing geometries, turbulence and other effects of the flow dynamics. Reactor design is also important when concerning processes that are liable to form solids, either inherently (e.g. nanoparticle synthesis), or undesirably (such as char formation). Small constrictions within reactors or flow systems may present potential regions for blockage formation, or allow for accumulation of solids, which may later con- taminate the product stream. In the case of hydrothermal metal oxide nanoparticle formation, an ambient temperature metal salt precursor stream is mixed with a superheated water stream. The rapid drop in solubility of the metal salt at the mixing point allows for a high degree of supersaturation, which effectively reduces the critical nucleation size, thus driving nanoparticle formation. This process of mixing the precursor with a preheated stream may be applied to almost any continuous flow process, and offers the ability to reach the desired reaction conditions virtually instantly; this can be a very useful technique for studying kinetics. The process of mixing an ambient temperature and superheated stream is not straightfor- ward due to the large differences in density and viscosity. Traditional mixing geometries such as T-pieces and Y-pieces produce poor mixing, with back-mixing and flow strat- ification often observed. Innovative reactor designs such as contraflow mixers are able to exploit the differences in density to achieve highly turbulent mixing, and to minimise recycling and stagnant zones. A pseudo fluid method is described as a technique for visualising mixing regimes within various reactor configurations under different conditions. In this process, ambient temperature water is represented by aqueous sucrose solution and supercritical water is represented using methanol. These fluids possess similar density and viscosity ratios to those between am- Panel IV: SCFs as Working Fluids / Process Technology and Design  211 bient temperature water and supercritical water. By ad- justment of the flow rates and pseudo reactor dimensions, similar Reynolds and Grashoff numbers can be achieved to those experienced in reactors under supercritical conditions. This technique allows quantification of mixing efficiency, as well as visualisation of issues such as flow recycling, stagnant zones, and other inconsistencies in the mixing dynamics. For a more genuine representation of flow path distributions within supercritical continuous flow systems, a technique involving injection and UV detection of chromophoric tracers is discussed. Using this method, residence time distributions can be compared between reactors, and the effect of stagnant zones at various points of the continuous flow system may be assessed. Such data provides useful experimental validation of CFD simulations for reactors. Other reactor geometries will also be assessed using these techniques, such as those involving concurrent mixing and others which feature multiple precursor stream inlets; the pros and cons of each will be discussed and contrasted to contraflow mixing. Acoustic Wave Generation in Near-Critical Supercritical Fluids: Effects on Mass Transfer and Extraction ACOUSTIC wAVE GENERATION IN NEAR-CRITICAL SUPERCRITICAL FLUIDS: EFFECTS ON MASS TRANSFER AND ExTRACTION

Bakhtier farouk, nusair hasan Department of Mechanical Engineering and Mechanics, Drexel University; Philadelphia, PA 19104, USA

Supercritical fluid extraction (SFE) is a technique that adds a supercritical fluid of an extraction medium to a sample containing a constituent targeted for extraction. Extraction by means of supercritical fluid can be expected to improve efficiency, including shorter extraction times and simplified procedures when compared with extraction techniques that employ organic solvents. Use of supercritical carbon dioxide has received recent attention as an environmentally friendly extraction technique that does not use hazardous organic solvents, as has been advocated by the green chemistry movement in recent years. The conventional process of extracting solutes from a solid matrix (packed bed) using supercritical solvents has a very slow dynamics even when solute free solvent is re-circulated and therefore improvements in the extraction process are required. The use of acoustic waves represents a potential effective method of enhancing mass transfer (extraction and separation) processes with supercritical fluids. Recent results of mass transfer enhancement by using resonant acoustic waves will be presented. Acoustically augmented flow and transport in supercritical carbon dioxide generated by standing wave in a cylindrical enclosure was simulated. The oscillatory flow field in the enclosure is created by the vibration of one of the end walls of the

 213 214  SFE 2013 | workshop on supercritical fluids and energy enclosure. The geometric parameters and the frequency of the vibrating wall are chosen such that the lowest acoustic mode propagates along the enclosure. A real-fluid model for representing the thermo-physical and transport properties of the supercritical fluid is considered. The fully compressible form of the Navier-Stokes equations is used to model the flow fields and an implicit time-march- ing scheme is used to solve the equations. The formation of the acoustic field in the enclosure is computed and fully described and the acoustic boundary layer development is predicted. The interaction of the wave field with viscous effects and the formation of streaming structures are revealed by time-averaging the solutions over a given period. Due to diverging thermo-physical properties of supercritical fluid near the critical point, large scale oscillations are generated even for small sound field intensity. The effects of near-critical property variations and system pressure on the formation process of the streaming structures are also investigated. Application of the acoustically augmented flow in extraction of caffeine from coffee beans using supercritical carbon dioxide is demonstrated numer- ically. The predicted results confirm that acoustic waves significantly accelerate the kinetics of the supercritical extraction process, especially in the near-critical region of operation and improve the final extraction yield. PANEL PRESENTATIONS

Panel V: Process Technology and Future Direction Developing an integrated supercritical fluid biorefinery for the processing of grains DEVELOPING AN INTEGRATED SUPERCRITICAL FLUID BIOREFINERy FOR ThE PROCESSING OF GRAINS

feral Temelli, ozan nazim ciftci Department of Agricultral, Food and Nutiritonal Science, University of Alberta; 4-10 Agr/For Centre, T6G2P5, Edmonton, Alberta, Canada; E-mail: [email protected], [email protected]

Limited supply of petroleum resources together with the ever increasing demand for petroleum-based products has fueled the emergence of the bioeconomy. Global trends highlight the growth in fuel, energy, materials, chemicals and other products based on renewable feedstocks as economically viable alternatives to petroleum-based products. This has led to the “biorefinery” concept of processing renewable feedstocks similar to that in a conventional oil refinery and petro-chemical complex, where crude oil is separated into various fractions and with further processing converted into a vast array of products. Thus, a biorefinery would integrate a variety of separation and conversion processes to produce multiple product streams from renewable feedstocks. Industrial-scale integrated biorefineries are critical for the growth of a sustainable bioeconomy. Grains of cereals and oilseeds are a promising source of renewable feedstock for biorefineries. Grains are composed of lipids, proteins, carbohydrates as well as moisture, ash and other minor components. Most of the conventional processes result in underutilization of the grains by focusing on only one or a limited number of components of the grains; therefore, the full value of grains is underestimated. In an integrated biorefinery, the first major stage would

 217 218  SFE 2013 | workshop on supercritical fluids and energy focus on the separation processes to fractionate the major and minor components of the grains. Then, in the second stage, these fractions would be converted to other high value ingredients/intermediates/products through various conversion processes. Finally, application development is critical for these ingredients/intermediates to be utilized in a variety of end uses, depending on their functionality, targeting food, nutraceutical, pharmaceutical, cosmetic, biofuel, biochemical, biomaterial and other industries. In addition to some of the conventional separation and conversion technologies, supercritical fluid technology has a major role to play in developing such an integrated biorefinery, considering the well-known advantages of supercritical carbon dioxide (scCO2). Among the major components of lipids, proteins and carbohydrates, scCO2 can selectively extract lipids, more specifically neutral lipids and lipid- soluble minor components, such as tocopherols, carotenoids and phytosterols. The residual proteins and carbohydrates would be of high quality and functionality as opposed to the case when petroleum-based solvents are used for lipid extraction. For example, canola proteins had better quality when lipids were extracted with scCO2 compared to those obtained after hexane extraction. The residual protein/carbohydrate mixture can be further fractionated using alkali extraction and/or subcritical water extraction technology. The crude lipids extracted by scCO2 can be fractionated to isolate the high-value minor lipid components. The neutral lipids, specifically triglycerides, can be used as is or can be converted to other valuable components through enzymatic or non-enzymatic reactions in scCO2 media. For example, triglycerides solubilized in scCO2 can be converted to biodiesel through lipase-catalyzed transesterification with methanol or ethanol to form fatty acid methyl or ethyl esters, respectively. Minor lipid com- Panel V: Process Technology and Future Direction  219 ponents can be encapsulated via various particle formation techniques, where the protein or carbohydrate fractions can be used as the coating material to form novel delivery systems for these bioactive components. All of the above scCO2-based unit operations have been demonstrated for various grains of cereals and oilseeds, rich in lipids. Over the past three decades, the know-how has progressed substantially towards integration of these unit operations to develop a biorefinery. However, there are challenges in terms of the large scale equipment and operations expected of biorefineries to be able to compete with the petroleum-based refineries. Therefore, it is critical to integrate the recovery of low-volume but high-value ingredients for favorable process economics. As well, defining the optimal scale of operation is essential to achieve economies of scale.

Construction of continuous scCO2 extraction units to replace the commonly used semi-continuous systems in operation today is essential to handle the large volumes of grains as feedstock. Feedstock diversity, including location and year-to-year variability, is another challenge for process optimization. This can be overcome by strate- gic location of biorefineries, targeting optimization of operations for the grain specific to that region. Environment friendly aspect of scCO2-based biorefineries may ease the protocols of acquiring regulatory permits. Building part- nerships with conventional industries that produce large quantities of CO2 can be a win-win situation to reduce greenhouse gas emissions. On the other hand, consumer education on the advantages of scCO2 technology is important to grow the demand for products of such a green technology, which in turn will force the industry to adopt supercritical fluid technology to a greater extent. The potential for employing scCO2 technology in an integrated biorefinery is just starting to be realized and offers prom- 220  SFE 2013 | workshop on supercritical fluids and energy ise for cost-effective and environmentally friendly process- Processing of Oligomeric ing of the grains to produce ingredients/products for food, Systems via SCE for Energy nutraceutical, pharmaceutical, cosmetic, fuel, chemical and Materials Applications and materials applications. Complete utilization of all the grain components in such a biorefinery will also reduce the food vs. fuel competition. It will also help meet the growing consumer demand for “natural” products processed with green technologies. scCO2-based biorefineries may play a key role in moving towards a sustainable bioeconomy via process intensification, by reducing energy requirements and waste streams, and increasing process efficiency while providing a range of food and non-food ingredients/products. PROCESSING OF OLIGOMERIC SySTEMS VIA SCE FOR ENERGy AND MATERIALS APPLICATIONS

David f. Esguerra, Julian velez, Adam scott, Mark c. Thies Dept. of Chemical and Biomolecular Engineering, Clemson University; 29634-0909, Clemson, SC, USA; E-mail: [email protected]

CARBONACEOUS PITChES AND OLIGOMERS Carbonaceous oligomeric pitches can be used as precursors for a variety of high-performance carbon materials for energy and materials applications, including cathodes for lithium ion batteries, high thermal conductivity carbon fibers, and carbon-based composites. These oligomeric materials can be produced from a variety of resources, including coal tar, petroleum by-products, and pure polycyclic aromatic hydrocarbons (PAHs), using either thermal or catalytic polymerization processes. A long-term goal of our group is to understand how the oligomeric composition of carbonaceous pitches affects their bulk properties. In previous work with pitches derived via thermal polymerization from the petroleum by-product decant oil, Thies and co-workers showed how supercritical extraction (SCE; also called dense-gas extraction, or DGE) could be used to isolate these petroleum pitches into their respective oligomers. The oligomeric fractions were then available for analysis using both conventional and advanced characterization techniques. Examples of information obtained therefrom included definitive molecular structures for the dimers of petroleum pitch, soft-

 221 222  SFE 2013 | workshop on supercritical fluids and energy ening points of dimer cuts, and the discovery of liquid crystallinity in trimer cuts. The goal of this study is to fractionate via SCE a carbonaceous pitch produced via the catalytic polymerization of the PAH monomer pyrene into its constituent oligomers. Isolating the oligomers of pyrene pitch would, for the first time, provide information about the oligomeric content of a pitch produced catalytically from pure PAHs. The use of both neat toluene (Tc = 318.6 °C; Pc = 41.1 bar) as the SC solvent, and the addition of N-methyl-2- pyrrolidone (NMP; Tc = 450.94 °C; Pc = 47.2 bar) as a co-solvent, is being explored. Previous work on the fractionation of carbonaceous pitches (typically carried out prior to an analytical characterization step) has been limited primarily to (a) solvent extraction methods, such as sequential Soxhlet extraction with the solvents benzene, pyridine, and quinoline, and (b) the simple separation of the pitch into solvent-soluble and insoluble fractions. However, as has been shown by Edwards and Thies, conventional solvent extraction methods produce fractions that are still quite broad in their molecular weight distribution (MWD). Thus, in the above- mentioned previous work, no information about the pre- ponderance of the various oligomers in the original pitch was reported, and the focus was on presenting average properties for pitch fractions isolated, versus definitive molecular structures.

Lignin from biomass by-product streams Another poorly defined oligomeric system for which supercritical fluid processing can provide unique advantages is the biopolymer lignin. Lignin is one of the most common organic compounds on earth, comprising about 30% of all organic carbon. Only cellulose is more abundant. Panel V: Process Technology and Future Direction  223

In a pulp and paper mill, the pulping process is used to dissolve away the lignin fractions of wood, liberating the cellulosic fibers from the wood matrix in the form of a pulp that is then used to make paper. This chemical digestion of the lignocellulosics in wood is accomplished through various pulping processes (with the kraft sulfate process being globally dominant), and the lignin ends up in a by-product stream known as “black liquor”. Typically, this black-liquor stream is burned in the recovery furnace of the paper mill for its fuel value and to recover the inorganic ash that is returned to the pulping process. If the high-ash (~50 wt%) lignin in this black liquor could be isolated in a dry, low-ash (0.5-2.0 wt%) state, the result would be an excellent-quality, low-cost biofuel with essentially the same energy content as coal and about 50% more energy than low-moisture wood pellets. Taken yet another step, if the lignin could be recovered in the “ultrapure” state, in particular with a low metals content and a controllable molecular weight, it would be much more than a fuel — it would be a high-value, renewable biopolymer. Such an ultrapure lignin would have a wide range of uses because lignin is unique among abundant biopolymers in having aromaticity. For example, researchers have suggested that an ultrapure lignin could be used as the oligomeric feedstock for manufacturing low-cost carbon fibers, which could then be used for automotive structural applications. The result would be dramatic reductions in the weight of the U.S. vehicle fleet — and concurrent increases in fuel mileage. In summary, lignin separated from Kraft black liquor has the potential to become an inexpensive and renewable platform for the production of aromatic chemicals, bio-based materials, and clean biofuels. However, the het- erogeneity of lignin presents a challenge for obtaining a 224  SFE 2013 | workshop on supercritical fluids and energy more fundamental understanding of the chemical struc- Supercritical technology ture of this material. This is where supercritical fluids can applied to food processing play a role. The fractionation of lignin via SCE processing has two potential benefits: (1) chemical structure-vs.-bulk property relationships can be obtained, and (2) the fractions themselves can have properties useful for various applications. SUPERCRITICAL TEChNOLOGy APPLIED TO FOOD PROCESSING

Julian Martínez LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Some solvents at high pressures are used as alternatives to liquid organic compounds in industrial processes, due to their lower toxicity, adequation to environmental exigen- cies, easy separation, and possibility of using moderate temperatures. In the food industry, carbon dioxide (CO2) is the most applied solvent, due to its non-toxicity. At high pressures, generally at the supercritical state, CO2 has been used as extraction solvent for coffee decaffeination, production of hop extracts and volatile oils used as condiments. In the research field, many groups have been working with supercritical CO2 extraction from novel sources, to obtain condiments, aromas and compounds with high nutritional or medicinal value. In food engineering the raw materials for extraction may be native plants or even wastes from the food industry, which often contain valuable compounds. As well as SFE, extraction with pressurized liquids (PLE) appeared as an alternative to extraction and fractionation of natural products, since it is a clean technology that allows controlling process parameters to tune the selectivity for a specific group of compounds, which is a feasible way to aggregate value to natural extracts. Water as a PLE solvent is non-toxic, non-flammable, cheap and environmentally safe. Indeed, PLE allows fast extraction

 225 226  SFE 2013 | workshop on supercritical fluids and energy in closed and inert systems at high pressure and moderate temperatures. Another advantage of PLE is that, at high pressures, solvents remain liquid at temperatures above their boiling point, where the solubility of some compounds may be enhanced. Of course, in this case the target compounds cannot be sensible to high temperatures. There- fore, PLE using water as solvent may be complementary to SFE with CO2, since the polar nature of water allows extracting compounds that would be insoluble in CO2. In this sense, one can use both techniques as sequential steps of a unique process, to obtain products with different properties from the same raw material. Ultrasound is used to increase the efficiency of extraction, since it reduces the required temperature and favors the dissolution of target compounds in the chosen solvent. Ultrasonic waves cause expansion and compression of bubbles in the solvent, which may collapse and lead to cavitation. Near natural raw materials, cavitation can result in rupture of cell walls, allowing the penetration of the solvent inside the cells, and thus enhancing mass transfer. In SFE, ultrasound can promote desorption of extractable material from the sold surfaces. Therefore, the application of ultrasound during extraction with liquid or supercritical solvents can increase the yield and velocity of the process. Bioactive compounds can be highly sensible to heat, light, oxygen or other adverse conditions. Moreover, the functionality of such compounds may be favored when they are gradually liberated into the organism. This is, mainly, the case of pharmaceutics, but it can also be applied to food ingredients. In this context, mechanisms to protect the compounds from adverse conditions and make possible their controlled liberation are needed. Encapsu- lation, through formation of micro or nanoparticles with polymeric matrices, is a known strategy to obtain such Panel V: Process Technology and Future Direction  227 results. Methods for particle formation using supercritical fluids have been explored as alternatives to consolidated techniques, such as spray-drying, fluidization or freeze-drying, and their results are promising. Among these techniques, some use the supercritical fluids as antisolvent, i.e., the supercritical fluid is used to remove a liquid solvent from a mixture, leading to the precipitation of particles inside the polymer. Two techniques can be highlighted in this context: Supercritical Antisolvent (SAS) Precipitation and Supercritical Fluid Extraction of Emulsions (SFEE). The advantages of supercritical technology for particle formation are the reduced need of handling materials that allows enhancing yield, easy equipment cleaning, and therefore, increased viability for scale-up, besides the possibility of operating in continuous mode. In the SAS process a liquid solution containing the target compound or product is brought to contact with a supercritical fluid. As a result, the liquid is saturated with the supercritical fluid, leading to the precipitation of the product. A polymer can act as encapsulation agent in this process, resulting in the formation of particles of the product involved or spread in the polymer. This technique has been studied for the precipitation of pharmaceuticals and bioactive compounds present in food, such as carotenoids. The main disadvantage of the SAS process, as well as of other precipitation techniques using supercritical fluids, is the control of particle size. It is difficult to obtain particles below micrometric scale, and particle agglomeration in frequent. The SFEE process may solve these problems, because in this case the precipitation occurs from droplets of an emulsion, where the target product is in the disperse phase. The supercritical fluid extracts the solvent from this phase, leading to the precipitation of the target compound with the polymer, and the particles remain suspended on the aqueous phase. Thus, the particle 228  SFE 2013 | workshop on supercritical fluids and energy size can be monitored through the size of the emulsion Analysis of saving of organic droplets. Due to the nature of the process, SFEE is recom- solvents in the recovery of mended to produce particles of compounds not soluble or antioxidants from vegetal poorly soluble in water, such as carotenoids, oils, and oth- sources by SFE er compounds with application in food. Finally, supercritical fluids can be reaction means in the synthesis of various products, as biofuels, and in the food industry, terpenic esters with flavor properties and sugar esters that can be applied as emulsifiers in processed food formulations. In these processes, immobilized enzymes catalyze reactions in supercritical CO2. Theoret- ical and practical works indicate that lipases are efficient in such processes, and can be used in various reaction cycles. As well as in SFE, the separation of the reaction products and the solvent can be achieved by pressure reduction. Therefore, supercritical fluids can replace toxic organic solvents that are typically employed as reaction means in the industry. Our research group has been concentrating its works on the mentioned techniques, with emphasis in products from natural sources with applicability in food processing and products. As examples, researches are being conducted on the following processes: SFE from red pepper, assisted or not by ultrasound, to obtain extracts with cap- saicin, and further encapsulation of the extracts with SAS or SFEE; recovery of anthocyanins and other phenolics from blueberry and blackberry wastes, for subsequent particle formation by SAS; extraction and encapsulation of bioactive compounds from passion fruit residues; and enzymatic synthesis of terpenic esters on supercritical CO2 to produce food flavors. Nine master and PhD students are involved in such works, and the process units are developed in our laboratory. The possibility of coupling different processes with supercritical fluids, or even to other clean technologies should be studied in future works of our group. ANALySIS OF SAVING OF ORGANIC SOLVENTS IN ThE RECOVERy OF ANTIOxIDANTS FROM VEGETAL SOURCES By SFE

Tiziana fornari Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM); C/Nicolás Cabrera 9, Campus de Cantoblanco, 28049 Madrid, Spain; E-mail: [email protected]

The processing of vegetal materials to recover phytochemicals with biological activity is currently an interesting matter of new markets. Supercritical fluid extraction (SFE) with carbon dioxide (CO2) is a competitive technology in this field, being one of the “Top Ten List” of CO2-SFE benefits the advantage of recovering the extract with high purity, completely free of solvent. Since no organic solvents are employed, subsequent processing for its elimination and recycling is not required. However, it is well known that the consumption of organic solvents in SFE not always can be circumvented. In fact, the supercritical CO2 extraction of polar or even moderate polar compounds generally requires the use of an adequate cosolvent to enhance yield and to design processes with acceptable economic profit. Hundreds of examples can be given in which the addition of a small amount of cosolvent (ethanol, aceto- nitrile, ethyl acetate, among others) produce considerably increases of extraction yield and recovery of target compounds. Among these target compounds a number of polar antioxidants, such as flavonoids and phenolic acids, require the use of cosolvents to attain their SFE from vegetal matter [1]. But even in the case of moderate polar antioxidants the use of small amounts of an acyl alcohol

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as cosolvent of CO2 considerably increase the extraction yield. In these cases, the most frequently proposed cosolvent is ethanol since its traces in the final product is permitted in food, nutraceutical or pharmaceutical applications. For example, it is well known that the solubility of several phenolics, including gallic acid, catechins, resveratrol, quercetin and salicylic acid, in CO2 containing small amounts of methanol or ethanol is considerable higher in comparison with their solubility in pure CO2 [2]. Thus, a remarkable increase in the recovery of these substances is observed if alcohol cosolvents are included in the supercritical CO2 extraction process [3]. Another example is the recovery of carnosic acid, a moderate polar lipophilic phenolic diterpene present in rosemary leaves. It has been reported that the addition of 5-10% ethanol as

CO2 cosolvent can duplicate extraction yield, producing a 4-7 fold increase of this antioxidant in the extract, while a minor effect on the recovery of essential oil constituents was observed [4]. Despite the benefits that the use of a cosolvent can produce in particular applications, when a cosolvent is employed the most outstanding advantage of SFE in comparison with solvent-based technologies seems to be somewhat lost. Thus, other extraction alternatives such as ultrasound assisted extraction (UAE) or pressurized liquid extraction (PLE) appear as competitive, because both are much more effective regarding organic solvent consumption in comparison with traditional solid- liquid extraction (SLE). The point is to assess the efficiency in terms of solvent consumption vs. recovery of target phytochemicals, which can be a decisive matter of analysis when selecting the extraction technology to be applied in a particular case. As a case of illustration, it can be mentioned the extraction of carnosic acid from the same lot of rosemary leaves (45 mg carnosic acid per g of dry Panel V: Process Technology and Future Direction  231 matter) using different techniques. Quite different results are obtained if the amount of antioxidant extracted was referred to the amount of liquid solvent employed. All SLE, UAE, PLE and SFE produced good recovery of carnosic acid (higher than 60%) under appropriate extraction conditions. Nevertheless, the consumption of ethanol is very different, when considering the mg of carnosic acid extracted per mL of ethanol consumed. UAE and PLE require one-fifth of the solvent employed in SLE to produce even somewhat higher recoveries. But, in comparison with the supercritical extraction (assisted or not with ultrasound) the increase of carnosic acid recovery per mL of ethanol employed is noteworthy (7-10 times higher). A comparison of the efficiency of using organic solvents in the recovery of antioxidants from several different plant matrixes and using different technologies will be presented and discussed. Antioxidants such as phenolic diterpenes, triterp- enic acids and carotenoids will be considered, and examples of SLE, UAE, PLE, and SFE with pure CO2 and assisted with ethanol cosolvent will be pondered.

Acknowledgements This work was financed by project ALIBIRD, S2009/AGR-1469 (Comunidad de Madrid, Spain).

References [1] E. Reverchon, I. De Marco, Supercritical fluid extraction and fractionation of natural matter, J. Supercritical Fluids, 38 (2006) 146-166. [2] R. B. Gupta, J-J Shim, Solubility in supercritical carbon dioxide, CRC Press, Taylor and Francis Group (2007). [3] M. T. Tena, A. Ríos, M. Valcárcel, Supercritical fluid extraction of t-resveratrol and other phenolics from a spiked solid Fresenius, J. Analytical Chemistry, 361 (1998) 143-148. [4] T. Fornari, G. Vicente, E. Vázquez, M. R. García-Risco, G. Reglero, Iso- lation of essential oil from different plants and herbs by supercritical fluid extraction, J. Chromatography A, 1250 (2012) 34-48. The production of fermentable sugars by the subcritical water hydrolysis of food industry residues ThE PRODUCTION OF FERMENTABLE SUGARS By ThE SUBCRITICAL WATER hyDROLySIS OF FOOD INDUSTRy RESIDUES

Juliana M. prado CTBE (Brazilian Bioethanol Science and Technology Laboratory) / CNPEM (Integrate Brazilian Center of Research in Energy and Materials); R. Giuseppe Máximo Scolfaro, 10.000, 13083-970, Campinas, SP, Brazil

Tania forster-carneiro, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Bioethanol has been investigated as a potential alternative to liquid fossil fuels due to its eco-friendly characteristics and relatively low production cost. First-generation bioethanol is produced today from raw materials that are rich in simple sugars or starch, such as sugarcane and corn. However, these crops are also food sources for both humans and animals. To avoid the fuel versus food dilem- ma, second-generation bioethanol aims to use non-edible raw materials as the source of fermentable sugars. Ligno- cellulosic residues from the food industry fulfill these requirements because they are not used as food sources and do not occupy farmable lands. The hemicellulosic and cellulosic fractions of the biomass can be hydrolyzed into fermentable sugars by several methods, using acid, alkali or enzymatic catalysts. With increasing knowledge of the processes that take place during the hydrolysis of biomass come new techniques, which are being exploited to improve the process. Sub/supercritical water hydrolysis (SWH) has been demonstrated to have significant potential for use as a highly efficient hydrolytic process with several

 233 234  SFE 2013 | workshop on supercritical fluids and energy advantages over conventional processes, such as the lack of need for pre-treatment, shorter reaction times, lower corrosivity, lower residue generation, the lack of use of toxic solvents and the reduced formation of degradation products. However, further optimization of the operating conditions (temperature, time, solvent:solid proportion) and economic evaluations of the process are still needed so that the technique can be scaled-up to the industrial level. A semi-batch unit equipped with a 50-mL reaction vessel that can operate up to 400 °C and 400 bar, with the possible addition of CO2 as an acid catalyst, was built. The unit was used to perform the subcritical water hydrolysis of sugarcane bagasse, pressed palm fiber, coconut husk and defatted grape seeds at water flow rates of 10-55 mL/min, temperatures of 200-300 °C, total processing times of 30-60 min and under 20 MPa of pressure. The results obtained using pure water as the reaction medium were compared with the results obtained using water + CO2 as the reaction medium. Fractions of the hydrolysate were collected every 2 min. The hydrolysates were analyzed for pH, total reducing sugars, monosaccharides and degradation products. The maximum total reducing sugars recovered for sugarcane bagasse was 23% at 214 °C and 55 mL/min using pure water as the reaction medium. For pressed palm fiber, coconut husk and defatted grape seeds, the maximum values of total reducing sugars obtained were 11.5%

(256 °C, with pure water), 14% (262 °C, with CO2), and 10%

(258 °C, with CO2), respectively. The total reducing sugars recovered increased with temperature; however, for the coconut husk and defatted grape seeds, the value only increased with the addition of CO2. The total degradation products increased with temperature, while the monosaccharides remained approximately constant, which means that more oligosaccharides were recovered at higher tem- Panel V: Process Technology and Future Direction  235 peratures, due to the increased efficiency in the break- down of cellulose. Each raw material presented different behaviors when subjected to the same operational conditions. Therefore, each lignocellulosic biomass should be individually studied for SWH. Nevertheless, SWH appears to be a promising technology for the recovery of fermentable sugars from lignocellulosic residues in the food industry.

Acknowledgements J. M. Prado thanks FAPESP (2010/08684-8) for the postdoctoral fellowship. The authors acknowledge funding from FAPESP and CNPq. The integral utilization of biomasses based on sub/supercritical fluids: Environmental, energetic and economic assessments of technological scenarios THE INTEGRAL UTILIZATION OF BIOMASSES BASED ON SUB/SUPERCRITICAL FLUIDS: ENVIRONMENTAL, ENERGETIC AND ECONOMIC ASSESSMENTS OF TECHNOLOGICAL SCENARIOS

Juliana Q. Albarelli, Adriano V. Ensinas, François Maréchal Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL); Station 9, CH-1015, Lausanne, Switzerland; E-mail: [email protected]

M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil

Second generation ethanol production has been an important line of research around the world. In the Brazilian scenario, sugarcane bagasse is the main material investigated for the production of cellulosic ethanol. The concept of integrating its production with the conventional technique of ethanol production from sugarcane in a biorefinery has been studied by different researchers. Experts agree that future biorefineries should focus on the production of high value products prior to biofuel and/or energy production. In view of this and considering the remaining obstacles for the establishment of a sugarcane biorefinery, the sub/supercritical technology stands out. Because such technology demands substantial energy consumption, strategies for energy consumption reduction must be developed in addition to process optimization. Currently, our research group is contributing to this scientific and techno- logic demand, comparing the sub/supercritical technology with other potential technologies at a su garcane biorefinery using simulation tools. Simulation tools play an impor-

 237 238  SFE 2013 | workshop on supercritical fluids and energy tant role as decision-support tools that assist in designing Polymer foaming with the infrastructure for cellulosic ethanol production and supercritical CO2 — Challenges sugarcane biorefineries. In this sense, the software ASPEN in batch-wise and continuously PLUS and VALI have been used to evaluate the main pro- operated processes cesses, including the supercritical extraction, supercritical hydrolysis and supercritical gasification of sugarcane bagasse. All of the processes analyzed are thermally integrated with the sugarcane biorefinery using Pinch Analysis. The processes are analyzed in light of their economic and environmental impacts, and multi-objective optimization is performed using the software OSMOSE, developed by LENISYSTEM/LENI/EPFL (Switzerland). In the near future, this project will also evaluate different technology scenarios developed mainly in LASEFI/DEA/FEA/UNICAMP that aim to integrate the use of different biomasses using sub/ supercritical fluids at all stages. In this regard, future biorefineries based on the sequential acquisition of secondary metabolites using supercritical ethanol and CO2, in addition to the subsequent fractionation of biomass using subcritical water and the production of monosaccharides from cellulose-rich solid waste using supercritical water, will be evaluated. Finally, the integration of the sugarcane and/ or microalgae biorefinery will be evaluated for the biorefineries studied, with the goal of obtaining energy efficiency and the economic and environmental impacts, as well as performing multi-objective optimization. POLyMER FOAMING WITh

SUPERCRITICAL CO2 — ChALLENGES IN BATCh-WISE AND CONTINUOUSLy OPERATED PROCESSES

sulamith frerich, Marcus petermann Ruhr-University Bochum; Universtitaetsstr. 150, IB 6/140, 44801, Bochum, NRW, Germany; E-mail: [email protected]

Polymers are versatile materials. They can be used in various shapes and colours, and their properties vary in a broad range. Once polymers are processed into foams, they show a high stability combined with low weight, due to the encapsulated gas. Usually, a foaming procedure consists of several steps. First, the fluidised polymer is mixed with a blowing agent. Second, the blowing agent causes the foam structure via nucleation and growth of gas bubbles into the polymer matrix. Finally, the foam needs to be stabilised. The foam morphology is distinguished between open cells and closed cells, depending on the pore structure. A combination of both types is possible, too, so-called integrated-foams with dense shells and porous cores. These foams show a very high rigidity, and the shell prevents water and dirt penetrating the foam [1]. Several substances have already been investigated as blowing agents, such as water vapour and low boiling organic liquids [2]. However, disadvantages like condensation during cooling (vapour) and residues in the foams (organic liquids) made their industrial application difficult, especially in the food industry. Therefore, alternative substances were investigated as blowing agents [3]. Super- critical fluids like nitrogen or carbon dioxide are promising

 239 240  SFE 2013 | workshop on supercritical fluids and energy substances. They show a high density at elevated temperatures and pressures and dissolve into the polymer. Hence, residue-free foams with fine pores can be created by depressurising a polymer-gas-system. Since the solubility of carbon dioxide in polymers is usually higher than nitrogen, its ability as blowing agent has been investigated. The application of polymer foams in thermal insulation requires very small pores, a low interconnectivity, and a robust polymer matrix. Nucleation and growth are competitive in creating the pore structure, and the final stabilisation has a great influence on the foam properties. It is therefore important to investigate the quasi-binary system polymer-carbon dioxide during the whole procedure and determine its behaviour and properties under different parameters. In general, the melt behaviour and rheology of the polymer-carbon dioxide mixture under high pressure and temperature influences its handling. Due to the dissolution of carbon dioxide into the polymer matrix, the melting temperature of the polymer decreases. This so-called gas induced melting point reduction enables economisation by saving heating energy. The gas-enriched polymer melt usually shows a lower viscosity, too. It is therefore easier to process the polymer through a plant. However, solubility and diffusion coefficients have to be determined, since they are influencing the amount of gas dissolved into the polymer, and therefore, the quality of porous structures created. The concentration of carbon dioxide in the polymer phase is crucial in the foaming procedure, as a certain amount of dissolved gas is needed to expand the polymer sufficiently. The mixing behaviour of polymers and carbon dioxide is also important, since a good miscibility enables foams with a more homogeneous pore size distribution. Panel V: Process Technology and Future Direction  241

Once the polymer-gas-system is depressurised, short chain length components such as additives or residue mono mers might be extracted. Thus, the properties of the remaining porous polymer matrix differ from them of the original polymer. The separation of the gas phase from the polymer foam is the most crucial step in processing. For producing polymer foams in large dimensions and quantities, continuous processes are preferable to batch-wise procedures. However, high pressure conditions in continuously operated procedures are more complicated to achieve, since their leak tightness has to be ensured. If a porous foam is created in a mould, the ability to separate between foam and mould is also of great importance, once the foam needs to be taken out. If it is generated as a free foaming mechanism, the separation rate of gas and foam should be limited to avoid disrupted structures. The simultaneous and consecutive appearance of thermodynamic phenomena during processing defines the properties and applications of the created foam.

References: [1] A. Kauffmann, H. Schüle, Schäumen, in: Eyerer, P. et al. (Ed.) Polymer Engineering – Technologien und Praxis; Springer, Berlin (u.a.), 2008, pp. 286-295. [2] F. A. Shutov, Blowing Agents for Polymeric Foams, in: D. Klempner, V. Sendijarevic (Hrsg.) Polymeric Foams and Foam Technology, 2nd edi- tion; Hanser, Munich, 2004, pp. 505-548. [3] V. Altstädt, A. Mantey, Thermoplast-Schaumspritzgießen, Hanser, München (2011).

POSTERS Obtaining Defatted Seeds and Oil Rich in Tocotrienols from Annatto by Supercritical Extraction: study of process parameters, scale-up and economic feasibility OBTAINING DEFATTED SEEDS AND OIL RICh IN TOCOTRIENOLS FROM ANNATTO By SUPERCRITICAL ExTRACTION: STUDy OF PROCESS PARAMETERS, SCALE-UP AND ECONOMIC FEASIBILITy

carolina L. c. Albuquerque, M. Angela A. Meireles Departamento de Tecnologia de Alimentos, Centro de Tecnologia e Desenvolvimento Regional, Universidade Federal da Paraíba – Campus V; Distrito Industrial de Mangabeira, Via Local, s/n., Quadra 252, Lote 501, 58.055-000, João Pessoa, PB, Brazil; E-mail: [email protected]

This work presents a study of the supercritical fluid extraction (SFE) of annatto oil to obtain defatted seeds and extract rich in tocotrienols. The work consisted in studying the process parameters, the scale-up and economic feasibility. A review of the annatto agribusiness showed a trend of using annatto due to the increasing consumer demand for natural products because the seeds are rich in tocotrienols, which are antioxidant and hypocholester- olemic substances. However, the socioeconomic evaluation of the producers, the recovery of higher quality extract, and the use of process byproducts were found as the main points that still needed to be improved. Supercritical Tech- nology has the advantage of obtaining solvent-free extracts and residue that add value to the products and byproducts of the process. Thus, a preliminary study of economic feasibility of the SFE process of annatto oil was carried out using the available data in literature. The study showed that the SFE of annatto oil was economically feasible with no data optimized, since the cost of manufacturing (COM) of extracts, for various industrial scales, were US$ 382.82/ kg (100 L), US$ 258.54/kg (500 L) and US$ 232.88/kg (1000

 245 246  SFE 2013 | workshop on supercritical fluids and energy

L). Therefore, optimized conditions of the process were determined with the experimental assays at 313 and 333 K and 20, 31, and 40 MPa. Larger amounts of oil were obtained in 333 K/40 MPa. In these conditions, kinect experiments were carried out and the COM of extracts was estimated as a function of extraction time. The optimization of process time decreased the COM for the capacities 100 and 500 L to US$ 124.58/kg and US$ 109.27/kg respectively. Extract more concentrated in δ-tocotrienol, (14.6 ± 0.4)% was obtained at 313 K/20 MPa. In this condition, the lowest bixin content was obtained in the extract, (0.9 ± 0.1)%. Therefore, an extract rich in functional substances and defatted seeds, and rich in bixin for later extraction were obtained with different feasible COM for industrial scales. The overall extraction curves (OECs) determined in a 5 L unit at 313 K/20 MPa showed that the scaling-up criterion used in the SFE simulation to estimate the COM was validated. The criterion was to keep constant the mass of solvent to mass of feed ratio (S/F) and the solvent residence time obtained in laboratory scale. The OECs in both scales had similar performance, with similar yield of extract and tocotrienols. The COM of the extracts was estimated for different scenarios considering three different stakeholders: investor, producer and colorant industries. The raw material cost ranged from 0.00 to 2.20 US$/kg. In the investor’s scenario, the best process time, from the economic standpoint, was 105 minutes, with COM (115±5) US$/kg for a 500 L and S/F of 8.7. For producer and industry scenarios, the lowest COMs were (40±6) US$/kg, (15±2) US$/kg, and (12±1) US$/kg, obtained at 28 minutes and S/F of 3.1 for capacities of 50, 300 and 500 L, respectively. The payback period ranged between 1-5 years for the producer selling oil, waste, and defatted seed which has high bixin content. The colorant industry use defatted seeds Posters  247 for colorant production, and sells the oil. This study showed that the SFE is economically feasible for units of at least 50L. Moreover, the process has the advantage of producing seed with reduced or controlled oil content, and extract with different concentrations of δ-tocotrienol, only by adjusting the operating conditions of the process. The subcritical water hydrolysis of annatto (Bixa orellana l.) seed residues ThE SUBCRITICAL WATER hyDROLySIS OF ANNATTO (BixA oRELLAnA L.) SEED RESIDUES

sylvia c. Alcázar-Alay, Tania forster-carneiro, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Lignocellulosic residues are potential sources of bioenergy due to their high availability and high renewable potential. Hydrothermal technologies, especially supercritical and subcritical technologies, have delivered excellent results in the conversion of biomass by a hydrolysis process that features the main advantage of using non-toxic solvents and less time for conversion in comparison to other methods of hydrolysis. Further, selectivity in the degradation of polysaccharides, proteins and lipids can be achieved by varying the water properties with temperature and pressure. The final products of hydrolysis are monosaccharides and oligosaccharides, pentoses, hexoses, organic acids and amino acids that are of significant commercial interest to the food, chemical and energy industries. Defatted annat- to seeds are obtained after the separation processes (the extraction of active soluble compounds and pigments, carotenoids) and then are destined as the raw material for use in the hydrolysis process. The separation of the fat fraction is conducted using the supercritical fluid extraction (SFE) method. In a subsequent process, the pigments are separated from the defatted seed using a low-pressure solvent extraction (LPSE) method, yielding a solid residue with a larger fraction of the initial lignocellulosic biomass

 249 250  SFE 2013 | workshop on supercritical fluids and energy that is free of pigments. Finally, the fermentable sugars in the biomass are obtained after performing the subcritical water hydrolysis of the defatted annatto. This study aims to determine the key operating parameters for obtaining the greatest percentage of fermentable sugars (water- soluble oligomers, monomers) and amino acids, as well as reducing the fractions of the degradation products of hydrolysis and organic acids using subcritical water. The main variables of the process are the temperature, pressure, solvent mass to mass feed (S/F) ratio and use of CO2. The hydrolysis products are analyzed for pH, total reducing sugars, monosaccharides and degradation products. The S/F is analyzed in the range from 1/5 to 1/15 (the highest ratios promote the dissolution of polysaccharides, while lower ratios promote lower water consumption). The effect of adding CO2 as a catalyst solvent is evaluated in the proportion CO2/H2O (v/v) 1/10. The temperature range is from 420 to 520 K (the subcritical region) and the pressure is between 10 and 20 MPa, which yields a condition in which the pressure of the medium is higher than the saturation pressure at all temperature conditions selected for this study. The results obtained with pure water as reaction medium are compared with the results obtained using water + CO2 as the reaction medium.

Acknowledgements The authors acknowledge the financial support from CAPES (DEA/FEA/ PROEX); and partial support from FAPESP (2009/17234-9 and 2012/10685-8) is also acknowledged. S. C. Alcázar-Alay thanks CAPES for the Ph.D. assistantship. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1). IDTq — A NEW RESEARCh GROUP LOCATED IN CORDOBA, ARGENTINA: PhASE EqUILIBRIUM, ExTRACTION, PURIFICATION AND MODELLING CAPABILITIES

Alfonsina E. Andreatta*, Juan M. Milanesio, Raquel E. Martini, M. f. Barrera vazquez IDTQ – Grupo Vinculado PLAPIQUI – CONICET – FCEFyN, Universidad Nacional de Córdoba; X5016GCA, Av. Vélez Sarsﬁ eld 1611, Córdoba, Argentina; E-mail: [email protected] *Universidad Tecnológica Nacional, Facultad Regional San Francisco; Av. de la Universidad 501, 2400, San Francisco, Córdoba, Argentina

IDTQ is a recently developed research group with a high potential and mainly focused on supercritical technology applied to the extraction of natural products and its use on human health, and also applied to solve energy problems. Plants with important properties for human health accompany mankind from its origins. In spite of the great evolution of health sciences, pathologies still exist without a definitive cure or with therapies that cause undesirable effects. Within this frame it is necessary to search new therapeutic agents. Traditional processes of extraction and purification of natural products are: pressing, hydro-distillation, steam stripping and liquid organic solvent extraction. These traditional methods require high residence time, big quantities of solvent and they present low selectivity. New techniques such as the application of supercritical fluids [1], microwave assisted extraction [2-4], ultrasound [4,5] and pressurized water [6,7] are among the new methods used in the industrial field to recover the bioactive compounds present in natural products. In this sense, we present dif-

 251 252  SFE 2013 | workshop on supercritical fluids and energy ferent natural products that were used to test these new The supercritical fluid extraction methods. The recovery of anthraquinones from extraction of antioxidant cegadera, tannin from grapeseed, catechins from green compounds from abiu skin tea and different bioactive compounds were studied in our lab. To model the equilibrium of these mixtures the use of a group contribution approach is a logical choice. In this way a group-contribution with association equation of state GCA-EOS [8] was applied to represent phase equilibrium data on mixtures containing the compounds in study with different solvents in a high range of condition including supercritical conditions. The extension of the GCA-EoS model will allow to represent a large set of natural products with complex chemical structures, and to evaluate traditional and supercritical processes using the equation predictive capability.

References [1] D. J. Miller, S.B. Hawthorne, J. Chemical & Engineering Data, 45 (2000) 315-318. [2] A. Navarrete Muñoz, Tesis Doctoral. Universidad de Valladolid, 2010. [3] B. G. Terigar, S. Balasubramanian, C. M. Sabliov, M. Lima, D. Boldor, J. Food Engineering, 104 (2011) 208-217. [4] S. Hemwimon, P. Pavasant, A. Shotipruk, Separations and Purification Technology, 54 (2007) 44-50. [5] M. Dabiri, S. Salimi, A. Ghassempour, A. Rassouli, M. Talebi, J. Sepa- ration Science, 28 (2005) 387-396. [6] M. D. Luque de Castro, M.M. Jiménez-Carmona, V. Fernández-Pérez, Trends in Analytical Chemistry, 18 (1999) 708-716. [7] D. J. Miller, S. B. Hawthorne, A. M. Gizir, A. A. Clifford, J. Chemical & Engineering Data, 43 (1998) 1043-1047. [8] H. P. Gros, S. Bottini, E. A. Brignole, Fluid Phase Equilibria, 116 (1996) 537-544. ThE SUPERCRITICAL FLUID ExTRACTION OF ANTIOxIDANT COMPOUNDS FROM ABIU SKIN

Elena M. Balboa, herminia Domínguez Departamento de Enxeñería Química, Universidade de Vigo; Campus Ourense, Ediﬁ cio Politécnico, As Lagoas, 32004 Ourense, Spain CITI-Universidade de Vigo; Parque Tecnolóxico de Galicia, Rúa Galicia 2, 32900 Ourense, Spain Angela M. farías-campomanes, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862 Campinas, São Paulo, Brazil; E-mail: [email protected]

carlos v. Lamarão pereira, valdir f. veiga Jr. Departamento de Química, ICE, Universidade Federal do Amazonas; Av. Gal. Rodrigo Octávio, 3.000, Coroado II, Manaus, Brazil

Abiu (Pouteria caimito) is a tropical fruit that is native to the Amazonian region of Brazil. Abiu is predominantly eaten raw or used for the preparation of juice or ice cream. The skin of abiu is not usable, so it is considered to be a residue of the peeling process. However, the skin contains a significant amount of oils and phenolic compounds. The abiu fruit has traditionally been used to relieve coughs, bronchitis and other pulmonary afflictions but also as as- tringent, anti-anemic and anti-inflammatory properties. Additionally, some studies have shown that abiu has a high phenolic content [1] and strong α-amylase and α-glucosidase inhibitory activities that reduce postprandial blood glucose levels [2]; as a result, it is believed that the skin of abiu also might possess interesting properties. Super- critical fluid extrac tion (SFE) is a clean process that can be used to obtain high-quality extracts from plants or

 253 254  SFE 2013 | workshop on supercritical fluids and energy derivatives. Carbon dioxide is the most commonly used solvent because it is cheap, environmentally friendly and generally recognized as safe (GRAS). Further, carbon dioxide has high diffusivity, allows for the recovery of solvent- free extracts because of its gaseous form at room temperature, and allows for the extraction of thermally labile or easily oxidized compounds because the process is carried out at low temperatures using a non-oxidizing medium [3]. The aim of this study is to determine the best conditions of antioxidant recovery from the skin of abiu by using supercritical carbon dioxide at varying conditions of pressure and temperature. Due to the lack of previous literature results on the SFE extraction of this raw material, a wide range of pressures (15, 20, 25, 30 and 35 MPa) and temperatures (40, 50 and 60 °C) were studied. The assays were performed in duplicate. The extracts were evaluated for global yield and antioxidant activity based on the coupled reaction of β-carotene and linolenic acid [4]. The abiu fruit was processed, and the residual skin was collected, dried, milled and stored at -18 °C in a plastic bag for protection from light. The extractions were carried out in a commercial SFE system equipped with an electric oven and a pneu- matic pump (Spe-ed SFE Laboratory System, 7071, Applied Separations, Allentown, USA). Because of the antioxidant capacity and phenolic content of abiu skin, the extracts are probable candidates for use as active ingredients in pharmaceutical, functional food and cosmetic industries.

Acknowledgments This work is part of the Ph.D. thesis of E. Balboa. E. Balboa thanks the Spanish Ministry of Education and Science for her FPI grant (BES-2010- 041807). A. M. Campomanes-Farias thanks CAPES/PEC-PG for the Ph.D. assistantship. The authors are thankful for the financial support from CNPq, CAPES-PROEX. Posters  255

References [1] S. A. Assis, J. C. R. Vellosa, I. L. Brunetti, N. M. Khalil, K. M. D. S. C. Leite, A. B. G. Martins, O. M. M. D. F. Oliveira, Antioxidant activity, ascorbic acid and total phenol of exotic fruits occurring in Brazil, Inter- national J. Food Sciences and Nutrition, 60, 5 (2009) 439-448. [2] P. M. De Souza, P. M. De Sales, L. A. Simeoni, E. C. Silva, D. Silveira, P. De Oliveira Magalhães, Inhibitory activity of α-amylase and α-glucosidase by plant extracts from the Brazilian cerrado, Planta Medica, 78, 4 (2012) 393-399. [3] M. Herrero, J. A. Mendiola, A. Cifuentes, E. Ibáñez, Supercritical fluid extraction: Recent advances and applications, J. Chromatography A, 1217, 16 (2010) 2495–2511. [4] P. F. Leal, N. B. Maia, Q. A. C. Carmello, R. R. Catharino, M. N. Eberlin, M. A. A. Meireles, Sweet basil (Ocimum basilicum) extracts obtained by supercritical fluid extraction (SFE): global yields, chemical composition, antioxidant activity, and estimation of the cost of manufacturing, Food Bioprocess Technology 1, 4 (2008) 326-338. Antioxidant, hypolipemiant and anti-obesity activities of Casearia sylvestris extracts obtained from SFE and LPE, and experimental phase equilibrium behavior determination ANTIOxIDANT, hyPOLIPEMIANT AND ANTI-OBESITy ACTIVITIES OF cAsEARiA syLvEsTRis ExTRACTS OBTAINED FROM SFE AND LPE, AND ExPERIMENTAL PhASE EqUILIBRIUM BEhAVIOR DETERMINATION

patícia Benelli, sibele R. Rosso comim, Evelin c. Azevedo, Rozangela c. pedrosa, sandra R. s. ferreira Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil; E-mail: [email protected]

Antioxidants, either as additives or as pharmaceutical supplements, can end radical reactions in vivo which can damage essential molecules such as nucleic acids and proteins. The natural antioxidant compounds have been isolated from different kind of natural products, including flavonoids, phenolic acids, terpenes, tocopherols and phospholipids. These compounds can also be responsible for hypolipemiant and anti-obesity activities, which mean compounds used for hyperlipidemia treatments (excess of cholesterol, triglycerides and glucose levels) and excess of weight gain. Casearia sylvestris is a native medicinal plant in Brazil, Peru, Argentina, Uruguay and Bolivia. The leaves of the plant are popularly used in folk medicine as antiseptic, topical anaesthetic, antitumor and antiulcer agents, and to heal skin wound diseases. In the Casearia extracts there are substances of great interest, such as coumarins, flavonoids and diterpenes, especially clerodane diterpenes as casearins and casearvestrins, which are bioactive with excellent cytotoxic and antitumor potential. Supercritical fluid extraction (SFE) is an alternative process to conventional extractions in various applications due to the pos-

 257 258  SFE 2013 | workshop on supercritical fluids and energy sibility to obtain solvent-free extracts and the use of low extraction temperatures, warranting the process selectivity towards the bioactive compounds. Considering the importance of these compounds the knowledge of the phase equilibrium of natural extracts in supercritical fluids, obtained by experimental measurements, is fundamental for determination of optimal conditions for separation and precipitation processes conducted at higher pressures, especially for food and pharmaceutical industries. The aim of the present project is to obtain and compare the extract attainment from C. sylvestris by SFE with CO2 and CO2 with co-solvent and low pressure extractions as Soxhlet (SOX) and maceration (MAC) with different solvents. The techniques efficiency was compared in terms of process yield and antioxidant capacity, evaluated by DPPH assay, β-carotene bleaching method and total phenolic content (TPC). The anti-obesity and hypolipidemic effects were also evaluated in vivo submitting Mus musculus Balb/c mice to a high-fat diet combined with C. sylvestris extracts during 30 days, monitoring the animals’ weight during the treatment and the final total serum cholesterol, triglycerides and glucose levels. The TPC presented maximum values of 169.4±0.6 mgGAE/g (SOX-ETOH) and 135±4 mgGAE/g (MAC-ETOH). The antioxidant potential by DDPH method resulted in effective concentration at 50% (EC50) values of 254±3 μg/mL (SFE 50 ºC/200 bar+11% ETOH) and 245±4 μg/mL (SFE 300 bar/50 °C+8% ETOH) and the β-carotene method presented values of 108±3% for SFE sample obtained at 50 ºC/300 bar+5% ETOAC and 110±1% obtained at 50 ºC/200 bar+2% ETOAC extract, after 120 minutes-reaction. The best anti-obesity results were obtained for the diet using SFE extracts 300 bar/50 ºC+5% ETOH and 300 bar/50 ºC+5% ETOAC among the extracts tested. The lowest cholesterol levels were provided by Posters  259

SOX-ETOH and SOX-ETOAC extracts and the highest glucose reduction were observed by treating the animals with SFE 300 bar/50 ºC and SFE 300 bar/50 ºC+5% ETOH extracts. The groups treated with extracts obtained at SFE 300 bar/50 ºC+5% ETOH and SOX-ETOAC presented lower triglycerides levels. The continuation of this work will perform the antioxidant evaluation by ABTS radical and lipid peroxidation in vitro (TBARS) methods and by the achievement of the extracts chemical profile by gas chromatography coupled to mass spectrometry analysis (GC- MS), in order to prove the presence of important compounds with biological activity. Also, the investigation of the phase equilibrium behavior of systems composed by C. sylvestris extract, organic solvent and supercritical CO2 will be held by means of the static synthetic method to afford information for the separation and precipitation/encapsulation processes. The Use of Supercritical Fluid Chromatography (SFC) in the Analysis of Petroleum, Gasoline and Kerosene ThE USE OF SUPERCRITICAL FLUID ChROMATOGRAPhy (SFC) IN ThE ANALySIS OF PETROLEUM, GASOLINE AND KEROSENE

Endler Marcel Borges, Mauricio A. Rostagno, Rodrigo Bisaia, guilherme Romão, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

flávio c. Albuquerque CENPES – PETROBRAS R&D Center; Av. Horácio de Macedo, 950, Cidade Universitária, 21941-915, Rio de Janeiro, RJ, Brazil

As an analytical technique, supercritical fluid chromatography (SFC) is complementary to both gas chromatography (GC) and liquid chromatography (LC). SFC can be applied to materials that are too heavy to meet the volatility and thermal stability requirements for GC. Supercritical fluids possess a combination of gas-like and liquid-like properties, which enables the elution of high-molecular-weight materials and faster solute transport within the column. This property also results in shorter analysis time for SFC relative to HPLC [1,2]. Hydrocarbon group separation is a very difficult task because high selectivity toward very similar molecules is required [3]. SFC with flame ionization detection (FID) has been shown to work well for hydrocarbon group analysis [4]. The American Society of Testing and Materials (ASTM) has accepted the use of SFC for the determination of aromatic contents of jet and diesel fuels [2,4] (ASTM D 5186- 96). However, this method is not applicable to crude oil because crude oil is significantly more complex in com-

 261 262  SFE 2013 | workshop on supercritical fluids and energy position than either jet or diesel fuel. For example, crude oil contains heavy compounds, such as asphaltenes, resins and several polar compounds. Evaporative light scattering detection (ELSD) was originally designed for LC for the detection of non-volatile compounds by mass [1]. In ELSD, the eluent is nebulized by a gas stream followed by solvent evaporation, typically in a heated drift tube. The remaining micro particles of the non-volatile solid or liquid analyte are then passed through a beam of light. The incident light is scattered by the particles and then collected by a photomultiplier apparatus, which generates the signal. Because the detection mechanism does not rely on the optical properties of the compound, ELSD is considered a universal detector and is ideal for detecting analytes without UV chromo- phores [5]. SFC-FID has been extensively used in the analysis of petrol and petrol derivatives due to the lack of a sensitive and universal detector that can be used for this purpose. However, the development of the ELSD detector has changed this situation; in this project, we present a SFC- ELDS method for the analysis of crude oil and oil derived products. Our main goal is develop a system and the necessary methodology for the separation of the different compound classes present in crude oil and oil products. The experimental conditions were optimized using a test mixture containing hexadecane, toluene, tetralin (1,2,3,4-tetrahydronaphthalene), naphthalene, pyrene, ben- zo(a)pyrene and anthracene [6] (test mixture 1). After method optimization, real samples of kerosene, diesel and petrol were analyzed. The separation of the constituents in petrol and petrol derivatives was optimized by varying several experimental conditions, such as the column [Spherisorb S5W Posters  263

(10 x 250 mm, 5 µm), Spherisorb CN (10 x 250 mm, 5 µm), Spherisorb SCX (10 x 250 mm, 5 µm), Viridis SFC 2-Eth- ylpyridine (10 x 150 mm, 5 µm)], the temperature (20-60 ºC), the back pressure (100-300 MPa) and the flow rate (2-12 mL min-1). The response dependence of ELSD on several common experimental parameters, including gas flow, co-solvent percentage, evaporation and nebulization temperatures, was tested with and without a column for each compound in test mixture. This work was carried out using modular equipment. The unique configuration of this equipment makes possible the elution (flush) of three consecutive connected columns; additionally, by changing the configuration it is possible to individually backflush each column to collect selectively each fraction that is separated. The first stage of method development was initially carried out using one column without back-flush. The next stage included the evaluation of two columns with individual back-flush capabilities. Finally, the last stage included the use of all three columns connected in series, followed by the sequential backflush of each column. The efficacy of our SFC-ELSD method was demonstrated for the analysis of several petrol, gasoline and kerosene samples, which were provided by the CENPES/ PETROBRAS.

Acknowledgements This work was carried out through cooperation between LASEFI/DEA/FEA/ UNICAMP and CENPES/PETROBRAS. The authors acknowledge the financial support from the Brazilian National Agency of Petrol [Agencia Nacion- al do Petróleo (ANP)].

References [1] B. N. Barman, V. L. Cebolla and L. Membrado, Critical reviews in analytical chemistry, 30 (2000) 75-120. 264  SFE 2013 | workshop on supercritical fluids and energy

[2] L. T. Taylor, Analytical chemistry, 82 (2010) 4925-4935. scCO2 Post-processing of [3] R. M’Hamdi, D. Thiéabaut and M. Caude, J. High Resolution Chroma- Materials for Biomedical tography, 20 (1997) 545-554. [4] B. E. Richter, B. A. Jones and N. L. Porter, J. chromatographic science, Applications 36 (1998) 444-448. [5] E. Lesellier, A. Valarché, C. West and M. Dreux, J. Chromatography A, 1250 (2012) 220-226. [6] T. Dutriez, D. Thiébaut, M. Courtiade, H. Dulot, F. Bertoncini and M. C. Hennion, Fuel, 104 (2013) 583-592. scCO2 POST-PROCESSING OF MATERIALS FOR BIOMEDICAL APPLICATIONS

Mara E. M. Braga, Ana M. A. Dias, hermínio c. de sousa CIEPQPF – Chemical Engineering Departament, FCTUC, University of Coimbra; Rua Silvio Lima, s/nº, Pólo II, Pinhal de Marrocos, 3030-790, Coimbra, Portugal; E-mails: [email protected], [email protected], [email protected]

Post-processing of finished commercially available polymer-based devices is a recent and attractive approach for the development of multifunctional biomedical devices and implants, drug release systems and tissue scaffolds. Materials that are intended to be used for biomedical applications should satisfy a wide range of requirements in terms of their biocompatibility/toxicity, surface chemistry/ morphology, porosity and pore morphology/interconnectivity, mechanical properties, degradation and bio-absorption rates and replacement rate by neo-tissues. The use of scCO2 for post-processing purposes is a particular ad- vantageous example which has been widely employed as a morphological, porogenic, foaming, viscosity reducer or a plasticizer agent for a wide range of applications that include polymer/composite processing, micronization of biocompatible polymers, encapsulation, impregnation or deposition of bioactive substances into solid matrices (polymeric/ceramic/composite), and extraction of undesired compounds from the synthesized materials. Some of these processes such as scCO2-assisted impregnation/ deposition method have an advantage for precise incorpo- ration of bioactive substances into polymeric, inorganic

 265 266  SFE 2013 | workshop on supercritical fluids and energy and composite materials in a short time and without the presence of harmful solvent residues. This process permits to load previously prepared biomaterials or even biomedical articles/devices without interfering with their intrinsic material properties during the manufacture and/or processing. The ability of polymeric devices to carry and release specific biological and/or synthetic bioactive substances, in a temporal- and in a 3D-controlled way, benefits the involved biological processes when they are used specifically to repair, to regenerate or even to replace a lost function of a tissue and/or organ involving the use of cells is studied in the tissue engineering field. Over the last years our research group has been studying the impregnation/ deposition method on finished devices. Examples of scCO2 processed biomaterials include contact and intraocular lenses, wound dressings, bioactive glasses, composites, scaffolds, etc. The impregnation/deposition of acetazol- amide and timolol maleate into commercial soft contact lenses to produce anti-glaucoma drug-loaded contact lenses was easily obtained by changing the operational pressure, temperature, processing time and depressurization rate conditions, to control the lenses drug loading capacities. This feature permits to adjust the final drugs release levels into specific and desired therapeutic limits without affecting the main properties of ophthalmic devices such as oxygen permeability, glass transition, contact angle and optical properties. Another example include the development of bioactive glasses (that will be used as bone substitute) loaded with dexamethasone, for which post-processing became an important step since the synterization process (required to produce glasses) restrains drug inclusion during the synthesis to avoid the thermo-degradation of the drug. This drug deposition method improved the biological activities of the prepared bioglasses, increased cell viability Posters  267 and presented osteogenic and anti-inflammatory properties, as confirmed by in vitro cell assays. These works demonstrate that the above referred scCO2-based post- processing methods can be very useful for the preparation of polymeric based materials with tunable physicochemical, thermomechanical, morphological and drug release properties, suitable for biomedical applications. Measurement of liquid-vapor and liquid-liquid-vapor equilibrium in CO2 + organic + ionic liquid ternary systems MEASUREMENT OF LIqUID-VAPOR AND LIqUID-LIqUID-VAPOR

EqUILIBRIUM IN CO2 + ORGANIC + IONIC LIqUID TERNARy SySTEMS

Roberto canales, Joan f. Brennecke University of Notre Dame; 182 Fitzpatrick Hall, 46556, Notre Dame, IN, USA; E-mail: [email protected]

Ionic liquids (ILs) are among the options for replacing conventional volatile organic solvents in industry, due to their interesting characteristics, such as low volatility, high thermal stability and the possibility of tuning their physical and chemical properties (high number of cation-anion combinations). However, separation of components from ILs is a challenge since distillation, heating and liquid-liquid extraction are not the best options if we need to process thermolabile compounds and to avoid using volatile organic solvents in the processes. Here we explore the idea we first suggested in 2002 [1] of using CO2 to induce liquid-liquid phase splits in IL + organic systems. Originally we showed that polar organics and water can be separated from ILs using CO2 [2-4]. For instance, when methanol is added to [bmim][PF6] it forms a single phase liquid mixture. Then, CO2 is added to the liquid phase at constant temperature and the increasing pressure results in a high solubility of the CO2 in the organic + IL liquid mixture. This also increases the volume of the liquid phase and eventually induces a phase split to obtain liquid-liquid-vapor equilibrium (LLV). The pressure at which this occurs is called the “cloud point”. If more CO2 is added to the system forming a LLV equilibrium, there is a pressure where the organic-rich phase disappears, dis-

 269 270  SFE 2013 | workshop on supercritical fluids and energy

solving the organic compound into the supercritical CO2 phase. This is called the “merging point”. This work is focused on measuring the separation of toluene from four different ILs based on the bis(trifluoro- methylsulfonyl)imide ([Tf2N]-) anion. Cations are 1-hexyl-3- methylimidazolium ([hmim]+), 1-hexyl-3-methylpyridinium ([hmpy]+), triethyloctyl phosphonium ([P2228]+) and tri- hexyltetradecyl phosphonium ([P66614]+). Two different apparatuses, a modification of those shown in another work from our group [4] are presented for measuring the composition in the different phases: a stoichiometric apparatus for solubility of CO2 in the single liquid phase mixture until the cloud point appears and an analytical apparatus for sampling the phases in LLV equilibrium, which ends in the merging point of the mixture as the pressure is increased. Solubility of CO2 in the toluene + IL mixture is measured at 298 K and 313 K (also 333 K for [hmim][Tf2N]) and pressures up to 8 MPa, with initial IL mole fraction of 0.30, 0.50 and 0.70. Results are compared with binary solubilities of CO2 in the different ILs and toluene.

The solubility of CO2 in the liquid mixture increases with increasing pressure and decreases at higher temperatures. The same trend is observed for binary systems of CO2 in ILs. The solubility of CO2 in toluene is lower than in the pure IL but a crossover is reached at an intermedi- ate pressure. The solubility of CO2 in liquids mixtures of toluene + IL increases as the initial concentration of IL is increased. The cloud point pressure is higher at higher temperatures and lower initial IL composition. The merging points increase at higher temperatures and we find that the values are not dependent on the initial IL concentration. Lower cloud point pressures are observed when using [hmim][Tf2N] and [hmpy][Tf2N], while slightly higher pressures are required for [P2228][Tf2N]. [P66614][Tf2N] Posters  271

shows the largest CO2 solubility in the binary and ternary systems, but this IL exhibits a very high cloud point pressure.

References [1] A. M. Scurto, S. N. V. K. Aki, J. F. Brennecke, J. American Chemical Society, 124 (2002) 10276-10277. [2] A. M. Scurto, S. N. V. K. Aki, J. F. Brennecke, Chemical Communica- tions, (2003) 572-573. [3] B. R. Mellein, J. F. Brennecke, J. Physical Chemistry B, 111 (2007) 4837-4843. [4] S. N. V. K. Aki, A. M. Scurto, J. F. Brennecke, Industrial & Engineering Chemistry Research, 45 (2006) 5574-5585. The recovery of high-value- added products from pressed palm fiber using integrated supercritical technology: Extraction and hydrolysis ThE RECOVERy OF hIGh-VALUE- ADDED PRODUCTS FROM PRESSED PALM FIBER USING INTEGRATED SUPERCRITICAL TEChNOLOGy: ExTRACTION AND hyDROLySIS

fiorela p. cardenas-Toro, Tania forster-carneiro, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

The use of agroindustrial residues has received significant attention in recent years because such residues can be used as a source of value-added products, such as bioactives for the food industry and fermentable sugars for second-generation ethanol. Supercritical technology provides an interesting option for the sustainable utilization of biomass as an alternative to conventional solvents. Supercrit- ical fluid extraction (SFE) and pressurized liquid extraction

(PLE) techniques use solvents, such as CO2 and ethanol, at elevated pressure and temperature to enhance extraction performance in comparison with soxhlet extraction in terms of selectivity. Subcritical water hydrolysis (Sub- WH) possesses the advantages of short conversion times and low residue generation; however, a deep understanding of the behavior of this technique is needed for sugar production optimization. Pressed palm fiber is a residue obtained from the oil palm industry and contains bioactive compounds, such as carotenoids (α- and β- carotene), which are important additives for antioxidant properties. Addi- tionally, this residue contains cellulose and hemicellulose, which are sources of fermentable sugars. The objective of this work was to study integrated SFE or PLE for the re-

 273 274  SFE 2013 | workshop on supercritical fluids and energy covery of extracts rich in carotenoids and, subsequently, Supercritical Fluid SubWH for the recovery of hydrolysates that are rich in Technologies, Inc. fermentable sugars. First, the integrated process of SFE and SubWH was studied. The effect of the operational parameters (pressure and temperature) on the SFE of carotenoids was investigated. The highest SFE extract yield was observed at 328 K and 20 MPa (2.6% d.b.), while the highest yield for carotenoid content was obtained at 318 K and 15 MPa (800 ppm in the extract). The defatted, pressed palm fiber was used as a raw material for the SubWH experiments. The optimal condition for a product possessing high sugar formation and low sugar degradation was found at 523 K, 15 MPa, a solvent/feed of 120 and a space-time of 2.5 min (yield of 23%, conversion of 84.9%). Second, an integrated process of PLE and SubWH was investigated based on the use of a new lot of pressed palm fiber. A central composite rotational design was carried out to evaluate the effects of pressure and temperature on carotenoid recovery. The continuous increment of global yield was observed with the increment of temperature and pressure, and the highest carotenoid recovery was found at 328 K and 4 MPa (4,000 ppm in the extract). Subsequent SubWH experiments for kinetic studies at 523 K and 15 MPa are under evaluation. Additionally, an economic analysis of the proposed integrated processes will be evaluated. The integration of extraction and hydrolysis provides a promising method for the recovery of carotenoids and fermentable sugars from pressed palm fiber.

Acknowledgements The authors thank the Agropalma S.A. Company for supplying the pressed palm fiber residues and acknowledge the financial support from (DEA/FEA/ PROEX), CNPq (560914/2010-5) and FAPESP (2011/19817-1 and 2012/10685- 8). F. P. Cardena-Toro thanks CAPES/PEC-PG (5945100) for the Ph.D. assistantship, and M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1). SUPERCRITICAL FLUID TEChNOLOGIES, INC.

Thayane carpanedo LabSolutions; R. Marquês de Olinda, 680, 04277-000 São Paulo – Ipiranga, SP, Brazil; E-mail: [email protected]

Rudy Baskette, Kenneth J. James Supercritical Fluid Technologies, Inc.; 19711 Newark, DE, USA; E-mail: ken.james@supercriticalﬂ uids.com

Supercritical fluid extraction (SFE) is an excellent method to concentrate flavors, fragrances, essential oils, biologically active compounds and materials of interest from flowers, leaves, fruits, bark, roots, buds, seeds, etc. SFE produces oils with standardized concentration of active ingredients and products with much higher yield and purity concentration of active ingredients and products. SFE also produces oils of higher quality than traditional methods and with less creation of artifacts. Hops can add remarkable depth to the flavor profile of a beer by amplifying fruity, spicy, woodsy, or citric flavors. This experiment will demonstrate that the SFT-110 SFE Unit can use supercritical carbon dioxide to separate aromatic and bitter hop components.

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VOLATILE OIL ExTRACTION FROM TURMERIC (cuRcuMA LongA L.) By SUPERCRITICAL CARBON DIOxIDE: STUDy OF ThE ExTRACTION IN BEDS OF DIFFERENT GEOMETRIES AND OPERATIONAL CONFIGURATIONS

pedro ivo n. de carvalho, Mauricio A. Rostagno, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Production of extracts from vegetal matrices with biological properties has attracted great interest of food, cosmetic, and pharmaceutical industries. Within this demand, the extraction process using supercritical carbon dioxide

(SFE-CO2) has been shown being a technically and economically feasible technology for the extraction of several substances. It has some advantages over conventional extraction techniques, both in terms of yield and quality of the extract. Thus, the first objective of this work is the application of SFE-CO2 in the optimization of volatile oil extraction from turmeric in laboratorial scale. This oil is rich in ar-turmerone, compound that has been reported in the literature by presenting some bioactive properties, such as, anti-inflammatory, antimicrobial, antioxidant and an- ticarcinogenic activity [1].

Currently, in the SFE-CO2 context it becomes important the generation of knowledge and methodologies of scale-up towards the industrial application of the SFE-CO2 process. However, some situations that may take place in extractors of industrial scale, and even, pilot scale, such as bed porosity, temperature gradient and inefficient sol-

 277 278  SFE 2013 | workshop on supercritical fluids and energy vent dispersion [2] have not been taken into account by the most simple criteria of scale-up. For instance, in tall extraction columns axial dispersion can occur and in extractors of larger diameters can result in heterogenic extrac tion due to radial effects inside of extractor [3]. In this work is proposed the study of bed geometry influence (height and diameter of the extractor), as well as of variations associated with this factor (as temperature gradient and solvent distribution), in the extraction kinetic of the turmeric volatile oil. The installation of a continuous SFE process is other important point in industrial scale. Continuous process of extraction is possible and avoids “dead” times in the process due to the steps of de-pressurization, unloading of exhausted substrate, loading of fresh substrate, and re-pressurization [4]. In a extraction plant equipped with two or more extractors, while one extractor is being reload with fresh raw material, the other one (or the others) is working [5]. With the extractors positioned in parallel the solvent stream is alternating between the columns in each period wherein the yield intended is reached. In this configuration mode, just one extractor is in operation. With two or more extractors positioned in series, the process is called counter-current. The supercritical carbon dioxide stream is put on in contact with the substrate more exhausted and then successively with the substrate more rich in solute. This work aims to define which the best configuration to the extraction columns (extractors in series or in parallel) taking into account technical and economical parameters using turmeric as raw material. The compounds present in the extract of the volatile oil will be identified by gas chromatography-mass spectrometry (GC-MS) and will be quantified by gas chromatography with flame ionization detection (GC-FID). Finally, Posters  279 the cost of manufacturing of extracts will be estimated using the simulator SuperPro Designer® 8.5.

Acknowledgements Authors are grateful to CNPq (470916/2012-5) for the financial support; partial support from FAPESP (2012/10685-8) is also acknowledged. Pedro Ivo N. de Carvalho thanks CNPq for the MSc. assistantship. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).

References [1] B. Chempakam, V. A. Parthasarathy, Turmeric, in: V. A. Parthasarathy, B. Chempakam, T. J. Zachariah (Ed.) Chemistry of Spices; CAB Interna- tional, 2008. [2] J. M. del Valle et al., Supercritical CO2 processing of pretreated rose- hip seeds: effect of process scale on oil extraction kinetics, J. Super- critical Fluids, 31(2) (2004) 159-174. [3] G. Brunner, Gas extraction. An introduction to fundamentals of supercritical fluids and the application to separation processes; Springer, New York, 1994. [4] R. Eggers, P. T. Jaeger, Extraction Systems, in: G. Liadakis, C. Tzia (Ed.) Extraction Optimization in Food Engineering; CRC Press, 2003. [5] G. A. Núñez, C. A. Gelmi, J. M. del Valle, Simulation of a supercritical carbon dioxide extraction plant with three extraction vessels, Com- puters and Chemical Engineering, 35(12) (2011) 2687-2695. Pre-salt reservoir fluid behavior PRE-SALT RESERVOIR FLUID BEhAVIOR

osvaldo chiavone-filho Department of Chemical Engineering, NT/PPGEQ/NUPEG, Federal University of Rio Grande do Norte (UFRN); Campus Universitário, Lagoa Nova, 59066800, Natal, Rio Grande do Norte, Brazil; E-mail: [email protected]

Eduardo Mach Queiroz, fernando Luiz pellegrini pessoa Federal University of Rio de Janeiro; CT, BL E, SL 209, Ilha do Fundão, 21949900, Rio de Janeiro, RJ, Brazil; E-mails: [email protected], [email protected]

The reserves of oil and gas in the pre-salt region are estimated in Brazil to be huge and the best are the expectations. This research work may initially be called “thermodynamic and transport fluid behavior of reservoir mixtures in the pre-salt conditions of temperature, pressure and composition”. The presence of species in supercritical conditions and in significant amounts should be taken into account, that is the case of carbon dioxide and methane. This fact plays certainly influence in reservoir behavior and this research work aims to describe this effect through two lines, i.e., phase equilibrium thermodynamics and flow process simulation. The methodology was basically directed to experimental data collection, study and definition of the mathematical models, and simulators, or computational tools, to describe the thermodynamic and transport fluid behavior of reservoir mixtures in the pre-salt conditions of temperature, pressure and composition. The characterization of the fluid was initially restricted to ten species: methane, ethane, propane, carbon dioxide, water, sodium chloride, calcium carbonate, cyclohexane, n-decane and

 281 282  SFE 2013 | workshop on supercritical fluids and energy hexacosane. The conditions of temperature and pressure of interest are initially 60 to 120 ºC and 120 to 700 bar, respectively. Therefore, species like methane, ethane, propane and carbon dioxide are in supercritical (SC) conditions. Another relevant information is that there exists wells of the pre-salt in operation that present outstanding production of 20 mil barrels per day, but at the same time many other wells show production much lower than expected. Thus a better understanding of the system in conditions of the pre-salt may explain these results of low production that are contradicting the expectations of the pre-salt. Preliminary simulations using a cubic equation of state are presenting and demonstrate that an adequate approach is able to give a panoramic view of the thermodynamic and transport properties. Results of phase en- velope, multiphase flash with stability test, density and viscosity are presented. It may be pointed out that the presence of carbon dioxide with concentration in the order of 15% plays influence in the studied properties of the mixture. Commercial simulators usually applied in the de- scription of reservoirs do not consider the presence of supercritical species in the evaluation of the thermodynamic and transport properties and this phase concept is fundamental in the pre-salt mixtures of severe conditions of pressure and temperature. Beyond the preliminary results of simulation, a brief revision of the adequate thermodynamic models to describe the pre-salt fluid behavior is presented. The experimental information selected, mainly volumetric measurements, for the systems of interest are collected in a form of a data bank collection. The pres- ences of water and salts are also considered and salt solubility measurements of carbonates under carbon dioxide atmosphere and in the presence of an organic solvent is presented and discussed. Furthermore, this experimental Posters  283 procedure is also described. Another observation for elec- trolyte systems is the evidence of high temperature and pressure vapor-liquid equilibrium data where the presence of dissolved salts is found in the fluid phase similarly as in the aqueous liquid phase. These evidences found in the literature reinforce the complexity of the mixtures formed in the pre-salt reservoir and demand of systematic research and also in cooperation between several laboratories. This cooperation is being feasible with the aid of the Human Resources Programs sponsored by the National Agency of Petroleum, Natural Gas and Biofuels and also by the Petrobras University. In this research a work group has been installed and has joined academic institutions covering the whole Brazil. These programs are forming students in the undergraduate and graduate levels and they are also critical mass to determine and calculate thermodynamic and transport properties in study. Green biorefinery based on supercritical carbon dioxide technology for the processing of distillers grains GREEN BIOREFINERy BASED ON SUPERCRITICAL CARBON DIOxIDE TEChNOLOGy FOR ThE PROCESSING OF DISTILLERS GRAINS

ozan nazim ciftci, feral Temelli University of Alberta; 6020-118 Street South Campus AFDP, T6H2V8, Edmonton, Alberta, Canada; E-mail: [email protected]

Even though supercritical carbon dioxide (scCO2) extraction has been accepted as a superior extraction method, the general interest is still towards the extraction of low- volume, high-value products. One way to widen the application of scCO2 extraction is by taking full advantage of the benefits of scCO2 processing, and this can be achieved by scCO2 processing as part of a biorefinery. Development of integrated supercritical processes for the green processing of dried distillers grains with solubles (DDGS) using the biorefinery concept to produce biodiesel, nutraceuticals, and high-value food ingredients such as encapsulates and delivery systems for bioactives as natural food ingredients is the main focus of this research. DDGS is an inexpensive byproduct of the ethanol industry. Currently, DDGS is used as a livestock feed. However, its real value is underestimated when its high lipid content and high value minor lipid compounds such as phytosterols, tocols and carotenoids are considered. Therefore, the objective of this project is to add value to DDGS by the extraction of lipids from DDGS with scCO2, fractionation of high-value components such as tocols, phytosterols and carotenoids from lipids of DDGS by scCO2, enzymatic conversion of extracted DDGS lipids to fatty acid methyl esters (FAME,

 285 286  SFE 2013 | workshop on supercritical fluids and energy

biodiesel) in a novel continuous scCO2 bioreactor, and production of micro- and nanoparticles using the minor lipid and the protein fractions of the DDGS. DDGS was demonstrated to be a good source of lipids and valuable minor lipid components, which can be extracted using scCO2. Developed biodiesel process based on lipase catalyzed transesterification of triglycerides yielded FAME contents of up to 95%, and has many advantages over conventional biodiesel process. It is simple, efficient and green. This process can use a variety of feedstocks, low quality oils, does not need catalyst removal, has fewer processing steps, no wastewater is produced and immobilized enzyme can be reused. No glycerol separation may be needed due to the very low glycerol content of the product. Ongoing particle formation studies using the supercritical antisolvent (SAS) process resulted in successful encapsulation of the high value minor lipids with the zein fraction of the corn DDGS residue obtained after lipid extraction. Encapsu- lates as small as 100 nm were achieved using the SAS process. scCO2-based biorefining of DDGS may be a promising way to add value to this byproduct; it may contribute to the sustainability of the ethanol plants and may potentially open a door for the scCO2 extraction of commodity oils. PhASE EqUILIBRIUM DATA OF MULTICOMPONENT SySTEMS FOR NANOENCAPSULATION PURPOSES

sibele R. Rosso comim, Thaís A. proença, natália Mezzomo, José vladimir de oliveira, sandra R. s. ferreira Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil; E-mail: [email protected]

Carotenoids and ω-3 fatty acids are substances present in the Pink shrimp (P. brasiliensis and P. paulensis) residue with potential application as additives in the food industry due to their nutritional importance, colorant potential, antioxidant and hypolipidemic activities. On the other hand, anthocyanis present in the grape pomace from Merlot (Vitis vinifera) besides being antioxidants may offer anti- inflammatory, anti-viral and anti-cancer benefits. However, these substances are highly unstable. In order to preserve the cited important biological activities, these extracts can be encapsulated by high pressure techniques, such as SAS (Supercritical Anti-Solvent process). The size control of particles formed in the SAS process depends on the knowledge of the equilibrium data of the involved compounds. Best conditions for SAS experiments, where smaller particles are formed, are defined in the P-x phase equilibrium diagrams as the single phase areas near the critical mixture point (with high anti-solvent content). Therefore, this work aimed to investigate the phase equilibrium behavior of the multicomponent systems: shrimp residue extract + acetone + carbon dioxide (CO2), pluronic + acetone + CO2 and shrimp residue extract + pluronic + acetone + CO2 in order to understand the changes in the acetone + CO2

 287 288  SFE 2013 | workshop on supercritical fluids and energy phase equilibrium behavior with the addition of extract The phase equilibrium data and/or polymer and determine temperature, pressure and of complex systems and a composition for the encapsulation processes. The shrimp pressurized liquid extraction residue extract was obtained by cold maceration with ac- study of Brazilian ginseng etone. The phase equilibrium data were acquired using (Pfaffia glomerata) ecdysteroids the synthetic static method. Phase equilibrium data for grape pomace extract with ethyl acetate and PLGA in CO2 are also being collected. Phase equilibrium data was obtained for CO2 mass contents from 49.93 to 98.05% at temperatures of 308 K, 313 K, 318 K and 333 K. The systems exhibited liquid-vapor equilibrium with transition pressures up to 9.38 MPa and a lower critical solution temperature behavior. The increase in temperature caused an increase in transition pressures. ThE PhASE EqUILIBRIUM DATA OF COMPLEx SySTEMS AND A PRESSURIzED LIqUID ExTRACTION STUDy OF BRAzILIAN GINSENG (pfAffiA gLoMERATA) ECDySTEROIDS

isabel c. n. Debien, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

This doctoral project is being developed in two steps, including the measurement of phase equilibrium data of complex systems [1,2] and a pressurized liquid extraction study of Brazilian ginseng (Pfaffia glomerata) ecdysteroids.

STEP 1 Biodegradable polymers have received increased attention in recent years due to their potential applications in the medicine and food industries, with significant focus given to poly (L-lactic acid) (PLA) mainly because of its biocompatibility and resorptive features. The synthesis of this biopolymer by the enzyme-catalyzed ring-opening polymerization of L-lactic acid in compressed fluids has been considered a promising route. The aim of this work is to report the relevant phase equilibrium data (cloud points) of L-lactic acid + (propane + ethanol) and L-lactic acid + (carbon dioxide + ethanol). Phase equilibrium experiments were conducted in a variable-volume view cell employing the static synthetic method, varying temperature from 323.15 K to 353.15 K and at pressures up to 25

MPa. The mass ratio of ethanol to CO2 or propane was held constant at 1:9. For the (propane + ethanol) + L-lactic acid, the sequence of vapor-liquid, liquid-liquid and vapor-

 289 290  SFE 2013 | workshop on supercritical fluids and energy liquid-liquid was observed, while for (carbon dioxide + ethanol) + L-lactic acid, only the sequence of liquid-liquid type transitions were recorded. The results show that the system of (propane + ethanol) + L-lactic acid presents UCST (Upper Critical Solution Temperature) transition type and an UCEP, whereas the system of (carbon dioxide + ethanol) + L-lactic acid exhibits LCST behavior.

Step 2 Species of the genus Pfaffia are popular substi tutes for Panax due to their similarities in morphology and bioactive properties. Among them, Pfaffia glomerata has received particular attention due to the presence of ecdysteroids. Commercially, this compound is obtained using conventional solid-liquid extraction methods, that is, by using large quantities of solvents. Today, more environmentally friendly methods are preferred, such as pressurized liquid extraction (PLE), which enables the rapid extraction of bioactive compounds under high temper atures. The aim of this step of the work is to study the pressurized liquid extraction of Brazilian ginseng (Pfaffia glomerata) ecdysteroids. The effects of temperature (333- 393 K), pressure (8-30 MPa) and solvent [ethanol and ethanol:water (80:20 v/v)] on the global yield of extraction, antioxidant activity and β-ecdysone content of the extracts from Brazilian ginseng (Pfaffia glomerata) roots were studied. The global yield of extraction increased with the increase in temperature, while pressure did not affect the extraction yield. When ethanol was used as the solvent, the global yields varied from 1.5% at 333 K to 5.0% at 393 K. For the mixture of ethanol:water, the global yields varied from 7.5% at 333 K to 25.1% at 393 K. As the temperature increased, the selectivity of the solvent decreased, promoting the co-extraction of other compounds in addi- Posters  291 tion to the ecdysteroids. This behavior may explain the slightly higher antioxidant activities observed for the extracts obtained at 333 K in comparison to those obtained at 363 and 393 K when using ethanol as the solvent; additionally, the pressure did not affect the response variable. A similar behavior was observed for the mixture of ethanol:water; however, at 333 K, the antioxidant activities increased from 8 to 20 MPa and then decreased. Further, ethanol was found to be more selective for the extraction of the ecdysteroids, where fractions containing up to 5 % of β-ecdysone were obtained using this solvent at 393 K. Thus, the better extraction condition for β-ecdysone was selected (393 K, 8 MPa and ethanol as the extracting solvent), and a kinetic extraction study was performed. After two hours of extraction (S/F approximately equal to 48), the raw material was not exhausted. However, the β-ecdysone content did not increase significantly after one hour of extraction. After, the commercial software SuperPro De- signer® will be used to evaluate the economic viability of the process [3].

Acknowledgments The authors acknowledge the financial support from CAPES (PROCAD 244/2007 and DEA/FEA/PROEX); partial support from FAPESP (2012/10685- 8) is also acknowledged. I. C. N. Debien thanks CNPq (CNPq 151165/2010-6) for the Ph.D. assistantship. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).

References [1] I. C. N. Debien, A. A. Rigo, M. A. Mazutti, J. V. Oliveira, M. A. A. Meireles, High-pressure phase equilibrium data for the L-lactic acid+(propane+ ethanol) and the L-lactic acid+(carbon dioxide+ethanol) systems, J. Supercritical Fluids, 79 (2013) 27-31. [2] I. C. N. DEBIEN, A. A. RIGO, M. A. MAZUTTI, J. V. OLIVEIRA, M. A. A. MEIRELES. High-pressure phase equilibrium data for the systems L-latic acid + (Propane + Ethanol) and L-latic acid + (Carbon dioxide + Ethanol). In: 10th International Symposium on Supercritical Fluids, 2012, San Francisco, CA, USA. 292  SFE 2013 | workshop on supercritical fluids and energy

[3] I. C. N. DEBIEN, R. VARDANEGA, D. T. SANTOS, M. A. A. MEIRELES. Updating traditional medicine: Optimization of pressurized liquid extraction of ecdysteroids from Bra- zilian ginseng roots. In: III Iberoamerican Conference on Supercritical natural-based medicated Fluids, 2013, Cartagena das Indias. biomaterials for wound dressing applications using greener processes UPDATING TRADITIONAL MEDICINE: NATURAL-BASED MEDICATED BIOMATERIALS FOR wOUND DRESSING APPLICATIONS USING GREENER PROCESSES

Ana M. A. Dias, Mara E. M. Braga, hermínio c. de sousa CIEPQPF – Chemical Engineering Departament, FCTUC, University of Coimbra; Rua Silvio Lima, s/nº, Pólo II, Pinhal de Marrocos, 3030-790, Coimbra, Portugal; E-mails: [email protected]; [email protected], [email protected]

Phytochemicals are biologically active chemical compounds, naturally occurring in plants, where they act as a natural defense system. They can be broadly classified into major (g/100 g of plant material) and minor (microgram to milligram range/100 g of plant material) constituents. Major constituents include carbohydrates, lipids and proteins while minor constituents include vitamins, minerals and health beneficial secondary metabolites (phenolics, terpenes, carotenoids, alkaloids, saponins, vitamins, pre- and probiotics, bioactive peptides, etc). These metabolites often present antioxidant, antimicrobial, anesthetic/stim- ulant, anti-inflammatory, anticancer or antimalarial therapeutic capacities (among others), which justifies the wider and common use of plants as medication tool in traditional and complementary medicine worldwide. The World Health Organization (WHO) supports traditional medicine provided it proves to be efficacious and safe. According to WHO reports, traditional medicines are estimated to be used by 60% of the world’s population and in some countries are extensively incorporated into the public health system. Some major categories of plant-derived products include phyto-pharmaceuticals, herbal medicines, natural

 293 294  SFE 2013 | workshop on supercritical fluids and energy health products, phyto-cosmetics and personal care products. The global demand for these products is increasing due to a renewed interest of consumers for natural-based products, since they are considered safer and more cost- effective when compared to synthetic counterparts. Wound healing is a specific health care area in which many plant- derived products have been applied since ancient times and this empirical knowledge still persists nowadays. Mod- ern wound dressings are developed taking into consideration three essential factors: that the dressing is able to provide proper physiologic wound environment, to act as a barrier for microorganisms and to stimulate healing. The later can be enhanced by the impregnation of the dressing with active substances like antibiotics, antimicrobial and/ or antiseptic agents to enhance the body’s own healing mechanism. Over the last years our group has been working on the development of medicated wound dressing materials using generally regarded as safe (GRAS) materials, solvents and techniques. Our aim is to develop biocompatible and/or biodegradable biomaterials loaded with natural based bioactive compounds and using supercritical fluid technologies (extraction and impregnation/deposition). These technologies are accepted as valuable alternatives to develop specialized materials for biomedical applications, for which restrictive toxicity/biocompatibility limits have to be accomplished. Biomaterials tested so far include agarose, chitosan (and several derivatives) and mesoporous nanostructured silica while different natural- based bioactive and/or plant extracts have been screened for their antioxidant, anti-inflammatory and/or analgesic bioactivity. These bioactive compounds include pure substance (such as quercetin, thymol and naphtoquinones) and lipophilic extracts of jucá (Caesalpinia ferrea) or jambu (Spilanthes acmella var oleracea) which are used in folk Posters  295 medicine as natural anti-inflammatory and analgesic wound healing agents, respectively. This work will present and discuss the main results obtained so far and which include natural extracts characterization, solubility of natural based compounds in scCO2 and physical-chemical-biological characterization of scCO2 loaded biomaterials according to standard methodologies that permit to select those that can be used as wound dressings (in terms of required porosity, fluid handling capacity, hydrophilicity, cytotoxicity, sustained release capacity and resilience). The use of biorefinery in the agricultural and food industries: Hydrolysis and gasification for bio-hydrogen ThE USE OF BIOREFINERy IN ThE AGRICULTURAL AND FOOD INDUSTRIES: hyDROLySIS AND GASIFICATION FOR BIO-hyDROGEN

Tania forster-carneiro, cristiana B. carneiro, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Juliana M. prado CTBE (Brazilian Bioethanol Science and Technology Laboratory), CNPEM (Integrate Brazilian Center of Research in Energy and Materials); R. Giuseppe Máximo Scolfaro, 10.000, 13083-970, Campinas, SP, Brazil

Mauro Berni NIPE-Interdisciplinary Centre of Energy Planning, University of Campinas (UNICAMP), SP, Brazil

A biorefinery is an industrial plant that fully utilizes raw materials, sustainably, for the concomitant production of food by-products with high added value and biofuels/energy. The organic residue recycling technologies used to produce new products with energy recovery are emerging as efficient and economically viable alternatives with significant potential in terms of production and market value. Brazil is recognized as a world leader in the export of food; however, the industrial activities of the agri-food sector generate significant amounts of organic waste. These residues could become a major renewable resource for the production of new chemicals, fuels and energy. There is significant debate today regarding the environmentally sound disposal of organic waste because, according to the law n. 12.305 of 2010, such waste can no longer be finally disposed in landfills. Sub/supercritical hydrolysis and gasification are among these emerging technologies. Re-

 297 298  SFE 2013 | workshop on supercritical fluids and energy cent research indicates that supercritical fluid technology is economically viable when compared with thermal gasification due to the high solubility of the biomass components in supercritical water, which generates a cleaner gas (no tar and pitch), as well as the highest concentration of bio-hydrogen. The challenge of this technology is the optimization of the operating parameters involved in the process to maximize the effects of temperature and pressure. The use of gasification technology with supercritical water presents significant advantages in comparison with the thermal gasification processes already utilized in drying steps. With respect to gas production, recent studies have shown that the primary gases produced during gasification with supercritical water differ significantly from the thermal gasification process: the gas produced is clean (no tar), the hydrogen content is higher, dilution by nitrogen (N2) is not observed and the concentrations of carbon monoxide (CO) and methane (CH4) are highly dependent on the operational conditions. The complete conversion of carbon is achieved after a relatively short residence time, and significant amounts of CO are found in comparison with the low methane concentration. Further, bio- hydrogen is produced directly at high pressures, which means smaller reactor volumes and lower energy for pres- surizing the gas in a storage tank are necessary. Currently, the production of biogas is exploited industrially by fermentation technology (biological treatment), and methane gas is one of the vectors of renewable energy. However, hydrogen gas (H2) is a clean gas and can be recycled. The use of hydrogen incorporates technology that eliminates the need for the deployment of new transmission lines, because the conversion of electrical or thermal energy can be performed on-site using the potential energy in small spaces. The challenge of this work is the associated bio- Posters  299 hydrogen production at lower temperatures (subcritical conditions, 200-374 ºC). It is expected that the operating conditions of the hydrolysis step, followed by gasification in subcritical water, favor the production of bio-hydrogen; the residence time is low due to the high solubility of the components of cellulose biomass. The use of lower temperatures represents a significant advantage, contributing to reductions of investment and operating costs, as well as maintenance. In this project, a new line of research is proposed to develop new products with high value-added technologies based on hydrolysis and gasification with subcritical/supercritical water. Extensive tests (bio-hydrogen and methane) with different operating parameters will be needed, as well as the determination of gas composition and assessments of the performance of different waste types (soy, sugarcane, peanuts, palm fiber, coconut fiber, grape seed and tomatoes wastes). This project proposes the production of a clean gas with a high bio-hydrogen concentration at lower temperatures (subcritical conditions, 200-374 ºC), seeking to reduce the production costs of sub/supercritical gasification at large scales. The assays are performed in LASEFI/UNICAMP, which has adequate infrastructure to achieve the proposed objectives of this project. Specifically, the location possesses several units for extraction and supercritical hydrolysis, most of which were designed and tested in the laboratory, and can be used with modifications to its configuration. The experiments were performed in a semi-batch unit equipped with a 50-ml reaction vessel was used for the SWH of raw materials (bagasse sugarcane, defatted grape seeds, pressed palm fiber and coconut husk). Each sample was inserted into the reactor, which was connected to the equipment, and the experiments were carried out using 10-35 g of raw material. Distilled water was pumped through the system 300  SFE 2013 | workshop on supercritical fluids and energy to remove residual air, and once the system was filled with A study of the particle water, the pump was stopped, and the micrometric valve formation of annatto was closed. The coil was heated, and the reactor was start- extract using supercritical ed. The heating coil temperature was set at the processing fluid technology temperature while the reactor was pre-heated to 120 ºC. The temperature stabilized at approximately 20 min after start, and the dynamic period of the process was started by pumping water at 33 mL/min through the system for 30 min. When the dynamic period was initiated, the reactor temperature was set to the processing temperature (200 ºC or 250 ºC), leading to the development of a temperature profile over time until the temperature had stabilized. The pressure was held constant at 20 MPa. Hydrolysate samples were collected every 2 min. All experiments were performed in duplicate. The hydrolysates were analyzed by HPLC for their contents of 5-hydroxymethylfurfural (5- HMF) and carbon-6 and carbon-5 (arabinose, fructose, galactose, glucose, mannose, xylose, cellobiose and raffi nose). The preliminary results indicate that higher concentrations of sugars were obtained from sugarcane bagasse, followed by fibrate coconut palm fiber and grape seeds. The total sugars yielded and the liquefaction degree also were obtained. A STUDy OF ThE PARTICLE FORMATION OF ANNATTO ExTRACT USING SUPERCRITICAL FLUID TEChNOLOGy

M. Thereza M. s. gomes, Diego T. santos*, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected] *Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL); Station 9, CH-1015, Lausanne, Switzerland

Particle design using supercritical CO2 has received significant interest over the past 20 years. Supercritical fluids have been used as solvents, solutes, and antisolvents for micro- and nanoparticle formation in a variety of compounds and have overcome all of the limitations of traditional techniques. In an effort to increase the value of extracts from annatto seeds, this study aims to coprecip- itate annatto extract and polyethylene glycol (PEG) using antisolvent processes, resulting in higher bioavailability and enabling the protection of the unstable compounds with respect to adverse conditions. The main pigments of annatto seeds are bixin and norbixin, which are valuable natural colorants. However, these seeds have acquired notoriety because they contain other important substances for human health, such as tocopherols, tocotrienols and geranylgeraniol. Due to the importance of these bioactive compounds, for which recent studies have demonstrated the protective effects of tocotrienols against neurodegen- erative diseases, atherosclerosis and cancer, as well as their antioxidant properties, obtaining these compounds was the goal of this study. Thus, to add value to the δ-tocotrienol-

 301 302  SFE 2013 | workshop on supercritical fluids and energy rich extracts obtained from annatto seeds using supercrit- Green Solvents for ical fluid extraction (SFE), we proposed the coprecipitation Precision Cleaning of the annatto seed extract and a polymer using SAS (Supercritical Antisolvent) and SFEE (Supercritical Fluid Extraction of Emulsions) processes. First, a homemade experimental apparatus was constructed by our research group, and the apparatus was validated using a model substance (Ibuprofen sodium salt). The effects of various operating conditions (temperature, pressure, CO2 flow rate, solution flow rate, injector type and concentration of ibuprofen sodium in the ethanol solution) on the precipitation yield, the energy consumption per unit of manufactured product, the residual solvent content and particle morphology were investigated using split-plot designs. Ibu- profen sodium salt was successfully micronized by the SAS process using the constructed unit. Then, SAS and SFEE processes were applied to the ternary system of polyethylene glycol (PEG) + dichloromethane + annatto seed extract to obtain dry coprecipitates and nanosuspensions, respectively. The particle size, precipitation yield, residual solvent content and morphology of the product as functions of pressure, temperature, solution to antisolvent flow rate and extract to PEG mass ratios are evaluated.

Acknowledgments The authors acknowledge the financial support from CNPq (564721-2010-7). M. T. M. S. Gomes thanks CNPq (140641/2011-4) for the Ph.D. assistantship. GREEN SOLVENTS FOR PRECISION CLEANING

heather E. grandelli, phillip Maloney, Robert Devor, Jan surma, paul E. hintze National Aeronautics and Space Administration; 870 Claytor Square, 24060 Blacksburg, VA, USA; E-mail: [email protected]

Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (< 1 mg/0.1 m2), especially flammable residue. Traditionally chlorofluorocarbons (CFCs) have been used in the precision cleaning of LOX systems, specifically CFC 113 (C2Cl3F3). CFCs have been known to cause the depletion of ozone and in 1987 were banned by the Montreal Protocol due to health, safety and environmental concerns. This has now led to the development of new processes in the precision cleaning of aerospace components. An ideal solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. High- lighted is a ‘green’ precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such

 303 304  SFE 2013 | workshop on supercritical fluids and energy as butterfly valves 18” in diameter. A fluorinated grease, Lignite Gasification in Krytox®, is investigated as a model contaminant in these Supercritical Water: preliminary studies, and aluminum coupons are employed Kinetics and Numerical as a model aerospace component. Preliminary studies are Study (revised) presented in which the experimental parameters are optimized for removal of Krytox® from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308-423 K, pressures in the range of 8.3-41.4 MPa, exposure times between 5-60 min and impeller speeds of 0-1000 rpm were investigated. Preliminary results showed up to 86% cleaning efficiency with the moderate processing conditions of 323 K, 13.8 MPa, 30 min and 750 rpm. LIGNITE GASIFICATION IN SUPERCRITICAL WATER: KINETICS AND NUMERICAL STUDy (REVISED)

simao guo, Liejin guo, hui Jin, Zhiwei ge, youjun Lu State Key Lab of Multiphase Flow in Power Engineering (SKLMF), Xi’an Jiaotong University (XJTU); Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China; E-mail: [email protected]

Supercritical water gasification (SCWG) is a clean and efficient technology to convert lignite to hydrogen rich gas. In order to know the quantitative rule of the lignite gasification in supercritical water (SCW), this work proposed a simplified reaction pathway for lignite gasification in SCW, and developed a quantitative kinetics model for describing production gases (H2, CO, CH4, CO2) yields. The kinetics model contained seven typical reactions (pyrolysis, liquefaction, steam reforming, methanation, water-gas shift reaction) occurred in supercritical water gasification including both homogeneous and heterogeneous reactions. Apparent activation energy and frequency factor of each reaction were obtained by fitting the experiments data (5~25 wt% lignite slurry, 650~850 ºC, 13~120 s residence time) using nonlinear least-square fitting method improved by genetic algorithm. Then, the kinetics model was applied in a three-dimensional computational fluid dynamics (CFD) model of a SCW fluidized bed reactor developed by the State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF). The CFD model was established for better understanding the complex physical and chemical reaction phenomena of SCWG of lignite in the reactor, and providing information for better reactor design /scale

 305 306  SFE 2013 | workshop on supercritical fluids and energy up. By comparing the simulated results with experimental Supercritical Fluid Extraction data, the CFD model was validated. Based on the CFD from Natural Products: An model, some valuable information such as the detailed Overview of the Mathematical flow field, temperature distribution, chemical component Modeling, Scale-up, Simulation distribution and particles residence time distribution in- and Economic Analysis of the side the reactor were obtained. The bottlenecks of com- Process pletely gasification of lignite were pointed out. The effects of the reactor wall temperature, preheated water temperature, lignite particle size and alkali catalysts on SCWG of lignite were numerical investigated by the CFD model. Moreover, several types of new reactor designs were evaluated by the CFD model, and the optimal design was proposed for further SCW fluidized bed reactor development. Finally, a comprehensive solution including both a new designed reactor and its operating parameters for completely gasification of lignite in a moderate reaction temperature condition was proposed. All these researches are not only helpful to develop the technology of SCWG of lignite, but also have theoretical values in other organics (e.g. biomass, waste organics) gasification in SCW. Key words: Supercritical Water Gasification (SCWG); Lignite, Kinetics, Fluidized Bed Reactor; Numerical Study. SUPERCRITICAL FLUID ExTRACTION FROM NATURAL PRODUCTS: AN OVERVIEW OF ThE MAThEMATICAL MODELING, SCALE-UP, SIMULATION AND ECONOMIC ANALySIS OF ThE PROCESS

susana p. Jesus, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Supercritical Fluid Extraction (SFE) is a high-pressure extraction technique in which the solvent is a fluid (usually carbon dioxide) in the supercritical state. It is a green technology that has been extensively studied in more than three decades of intensive research. As a result, a solid knowledge base of the fundamentals of SFE has already been established, and significant amounts of experimental data are available in the scientific literature. The SFE process has been applied on the commercial scale since the 1980s [1]. Further, a wide number of industrial plants of various capacities have been built during recent decades. These operating plants are mostly distributed in Europe, the USA, Japan, and in the South East Asian Coun- tries [2]. However, in Brazil and many other countries, SFE processes are not yet carried out on the commercial scale. Therefore, SFE can still be considered an emerging technology because the conventional methods are the most commonly used approaches in various applications of solid-fluid extraction. In particular, this fact is the result of the requirements of high-pressure processes, which ne- cessitate higher investment costs in comparison to low- pressure plants. Nonetheless, it is well known that several

 307 308  SFE 2013 | workshop on supercritical fluids and energy other costs (in addition to investment costs) also must be considered when estimating the cost of manufacturing (COM) of some desired products [3]. Today, one of the crucial challenges in SFE investigation is to show that this process can be commercially competitive in a variety of situations. Accordingly, special attention must be given to the information that is required for preliminary studies of process design and cost estimation. The main goal of this work is to evaluate the calculation procedures used to obtain process design data that may be applied in preliminary studies of economic feasibility. For this purpose, some experimental data (available from previous works performed by our research group) are being used to investigate the mathematical modeling, scale-up, simulation and economic analysis of the SFE process. First, the mathematical modeling of the overall extraction curve (OEC) was studied, with focus on the application of low-complexity models. The spline model, as presented by Meireles [4], was successfully applied to describe the kinetic data of SFE from rice bran oil soap- stock. The results obtained are detailed in the recently published work by Jesus et al. [5]. Second, a more complete evaluation of the mathematical modeling of the OEC was performed using the kinetic data from five different raw materials (clove, ginger, grape seed, sugarcane residue, and lemon verbena). The main purpose was to carry out a comparison between the spline model [4] and the model developed by Sovová [6]. These models were evaluated by considering the fitting performance (mean square error and distribution of the residuals) and the applicability of the adjusted parameters in terms of providing useful information for process design. A subsequent part of this work will comprise some aspects of scale-up, simulation, Posters  309 and cost analysis. Estimations of large-scale data will be performed according to the scale-up criterion proposed by Prado et al. [7] in a previous work from our research group. The simulation of the SFE process on an industrial scale and the economic analysis will be performed using the commercial software SuperPro Designer® (Intelligen, Inc., USA).

Acknowledgements The authors acknowledge the financial support from CAPES (DEA/FEA/ PROEX). S. P. Jesus thanks CNPq (141828/2010-2) for the Ph.D. assistantship. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).

References [1] G. Brunner, Gas extraction: An Introduction to Fundamentals of Su- percritical Fluids and the Application to Separation Process. 1. ed., Steinkopff; Darmstadt; 1994. 387 p. [2] G. Brunner, Supercritical fluids: technology and application to food processing, J. Food Engineering, 67 (2005) 21-33. [3] P. T. V., Rosa, M. A. M. Meireles, Rapid estimation of the manufacturing cost of extracts obtained by supercritical fluid extraction, J. Food Engineering, 67 (2005) 235-240. [4] M. A. A. Meireles, Extraction of bioactive compounds from Latin Amer- ican plants. In: J. Martinez (Org.). Supercritical fluid extraction of nutraceuticals and bioactive compounds, Boca Raton: CRC Press – Taylor and Francis Group, 2008, 243-274. [5] S. P. Jesus, M. N. Calheiros, H. Hense, M. A. A. Meireles, A Simplified Model to Describe the Kinetic Behavior of Supercritical Fluid Extraction from a Rice Bran Oil Byproduct, Food and Public Health, 4(3) (2013) 215-222.

[6] H. Sovová, Rate of the Vegetable Oil Extraction with Supercritical CO2: I. Modeling of Extraction Curves, Chemical Engineering Science, 3(49) (1994) 409-414. [7] J. M. Prado, G. H. C. Prado, M. A. A. Meireles, Scale-up study of supercritical fluid extraction process for clove and sugarcane residue, J. Supercritical Fluids, 56 (2011) 231-237. Study on furfural gasification characteristics in supercritical water and its reaction pathway STUDy ON FURFURAL GASIFICATION ChARACTERISTICS IN SUPERCRITICAL WATER AND ITS REACTION PAThWAy

hui Jin State Key Lab of Multiphase Flow in Power Engineering (SKLMF), Xi’an Jiaotong University (XJTU); Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China; E-mail: [email protected]

Liquid fuel such as alkane and oxygenated fuel can be produced from biomass depolymerization product, and the process hydrogen is consumed. At the same time, a great amount of by-products wastes production is inevitable, so hydrogen production by supercritical water gasification from the by-products wastes production makes this technology have more independence and better economy. How- ever, publication about hydrogen production by supercritical water gasification from by-products wastes from biomass depolymerization is quite limited and the key hurdle prevent furfural from complete gasification of the wastes is still unknown and the optimal operational parameters. A high throughput (6 channels) gasification apparatus is established in State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF) for the supercritical water gasification and furfural is selected as a model compound. Temperature range of 400 ºC~700 ºC, pressure range of 25 MPa~40 MPa, reactor residence time of 0 minute ~ 20 minute, concentration of 2 wt% ~ 30 wt% were selected for the exploration of the complete gasification condition. The quantitative and qualitative analysis of the gaseous products are operated by Gas chromatography/Mass spectra and wet type gas meter. The main compounds of the

 311 312  SFE 2013 | workshop on supercritical fluids and energy liquid products are analyzed by Gas chromatography/Mass Two-phase flow spectra and total organic carbon. The solid residual is an- characteristics in alyzed by scanning electron microscope and Fourier trans- supercritical water form infrared spectroscopy and Industrial analysis and fluidized bed elemental analysis. A thermodynamics model based on the Gibbs free minimization energy was proposed to show the chemical reaction limit and to predict the products distributions. Equation of state of the mixing rule by Duan is adopted. It is predicted that furfural can be gasified completely in supercritical water and the main gaseous products are hydrogen and carbon dioxide. A reaction kinetics analysis is conducted to make clear the influence of the key reaction path with the operating condition. It can be concluded that the main intermediates are cyclopenta- none, propionic acid and phenols. The research results supplies the possibility of providing the optimal reaction condition for the main reaction of furfural gasification in supercritical water, retaining the side reaction and realiz- ing the orientation gasification of furfural in supercritical water. TWO-PhASE FLOW ChARACTERISTICS IN SUPERCRITICAL wATER FLUIDIzED BED

youjun Lu, pengfei Zheng, Liping Wei State Key Lab of Multiphase Flow in Power Engineering (SKLMF), Xi’an Jiaotong University (XJTU); Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China; E-mail: [email protected]

Supercritical water fluidized bed is a new reactor concept for biomass gasification. Two-phase flow characteristics in supercritical water fluidized bed have a significant effect on the heat and mass transfer, contact between particle and fluid, and chemical reaction. Firstly, an experimental study on the hydrodynamics of a supercritical water fluidized bed was conducted. The frictional pressure drops of a fixed bed and a fluidized bed were measured for a temperature ranging from 633 to 693 K and pressure ranging from 23 to 27 MPa. The results show that the Ergun formula for calculating the frictional pressure drop of a fixed bed can still be applied in supercritical water conditions. The average deviation between Ergun formula and experiment results is 13.3%. A predicting correlation for the minimum fluidization velocity in a supercritical water fluidized bed was obtained based on the experimental results of a fixed bed and the fluidized bed pressure drop. The average error between the correlation and experiment results was about 3.1%. However, experimental study is still very difficult because of its severe operating conditions in the SCW fluidized bed. Therefore, the two-phase flow characteristics in the supercritical water fluidized bed have been studied with Discrete Element Method, in order

 313 314  SFE 2013 | workshop on supercritical fluids and energy to provide theoretical basis for design and structure optimization of a supercritical fluidized bed reactor. The drag model provided by Wen & Yu (1966), Gidaspow (1987), and Syamlal & O’Brien (1989) were evaluated through modeling the bed expansion, solid particle velocity, and bed pressure drop, and minimum fluidization velocities of SCW fluidized bed. In simulation, the density and viscosity of SCW fluid were 283.79 kg/m3 and 3.67×10-5 Pa∙s, and the density and diameter of particles were 2580 kg/m3 and 0.5 mm. Based on the simulation results, both Gidsapow and Syamlal & O’Brien drag models predicate similar bed expansion height, pressure drop, and particle velocities distribution. Comparing to Gidsapow drag model and Syamlal & O’Brien drag model, Wen & Yu drag model pred- icates higher bed expansion height and higher pressure drop when u/umf<1.2, but lower bed expansion height when u/umf 1.2. The deviation of minimum fluidization velocity between simulations and experimental results were with 2.85% for Gidsapow drag model and Syamlal & O’Brien drag model, but 8.75% for Wen & Yu drag model. Therefore, it is suitable to simulate SCW fluidized bed by using Gidsapow drag model or Syamlal & O’Brien drag model. The huge divergences of two-phase flow characteristics in SCW fluidized bed and in gas-solid fluidized bed can be found by comparisons of bed pressure drop, average particle height and bubble characteristics. The density and viscosity of gas used in present study are 0.33 kg/m3, and 2.38×10-5 Pa∙s. When superficial velocity was above the minimum fluidization velocity, the amplitude of pressure drop of gas-solid fluidized bed is greater than that of SCW fluidized bed. The bed pressure drop power spectrum analysis shows that the dominant frequency is 2.8 Hz for SCW fluidized bed, but 3.2 Hz for gas-solid fluidized bed, which indicates a stronger bubble collision ratio, coales- Posters  315 cence, and break open in gas-solid fluidized bed. The number and size of bubbles in gas-solid fluidized bed is greater than that in SCW fluidized bed at the same bed height level. Also, the effect of superficial velocity, temperature and pressure on bubble amount, bubble size and bubble velocity is revealed respectively in SCW fluidized bed. The results in this paper are useful for the design of SCW fluidized bed. Supercritical Desorption of Carotenes from Alumina Adsorbents SUPERCRITICAL DESORPTION OF CAROTENES FROM ALUMINA ADSORBENTS

M. A. E. cunha, A. L. santana, c. f. M. Batista, f. f. M. Azevedo, M. E. Araújo, n. T. Machado Laboratory of Separation Processes and Applied Thermodynamic, Faculty of Chemical Engineering (UFPA); Rua Augusto Corrêa, 1, 66075-900, Belém, Pará, Brazil; E-mail: [email protected]

Buriti (Mauritia flexuosa, Mart), a native palm growing in swamps and flooded areas along rivers and forests on the Amazon region, is one of the palms with the highest economic potential because its oil is a rich natural source of pro-vitamin A. The fruits of Buriti have a soft and oily dark-yellow to reddish pulp, containing between 20-30% (wt.) of a reddish oil with the highest concentration of carotenes in vegetable oils, with an estimate annual average oil specific production of 57.5 ± 17.0 kg.ha-1, having a great economic potential of application in the food and cosmetic industries because of its effectiveness on the treatment and prevention of diseases caused by deficien- cy in vitamin A, use as natural plasticizer for starch, absorption and photoluminescence optical properties, low cytotoxicity in creams and lotions formulations, and pho- toprotective properties against UVA and UVB irradiation on cells. Since the pioneer work of Model et al., supercritical carbon dioxide has been applied on desorption of synthetic chemicals (e.g. phenol, ethyl acetate, benzene, toluene, naphthalene, phenanthrene, hexachlorobenzene, penta- chlorophenol, and isomeric dimethylnaphthalene mixtures, DDT, n-hexane, methyl ethyl ketone, and toluene, ethyl acetate and furfural, m-xylene, benzoic acid or salicylic

 317 318  SFE 2013 | workshop on supercritical fluids and energy acid), essential oils (e.g. lemon, bergamot, mandarin, lime and bitter orange oil), and even fat-soluble substances from vegetable oils (carotenes, β-carotenes, tocopherol acetate, α-tocopherol), loaded in different adsorbents (e.g. silica gel, aluminum oxides, γ-alumina, activated carbon, cellulose, bentonite, magnesium silicate, and zeolite), as reported in the literature. Despite the development of several processes to recover and concentrate carotenes from vegetable oils by traditional methods, particularly crude palm oil, degummed palm oil, palm fatty distillates and refined, bleached and deodorizer palm oil reported in the literature, only a few works have been reported concerning the application of supercritical adsorption/desorption processes to recover and/or enrich carotenes from vegetable oils, including batch adsorption of crude palm oil in stirred tanks followed by supercritical desorption, supercritical adsorption of Buriti oil (Mauritia flexuosa, Mart) related compounds in γ-alumina adsorbent using carbon dioxide. In this work, enriching of carotenes has been systematically investigated by supercritical desorption process. The desorption of carotenes from preparative columns packed with γ-alumina adsorbents loaded with Buriti oil has been determined experimentally at 20 and 25 MPa, 333 K, and solvent flow rate of QCO2 = 10.6 l/min, using a high pressure apparatus with a jacket autoclave (Mechanical Work- shop, TUHH-Germany) of 1000 cm³, adapted to be used as a desorption cell by assembling 01 (one) cylinder of 2.7 cm internal diameter and 14.25 cm height inside the high pressure vessel of 1000 cm³, a diaphragm-type compressor (Andreas Hofer Hochdrucktechnik GmbH, Model: MKZ 120-50), a sampling system with a separator of 130 cm³ (Mechanical Workshop, UFPA-Brazil), a thermostatic bath (Haake Mess-Technik GmbH, Model N3), a carbon dioxide reservoir and a gas meter. Buriti oil has been characterized Posters  319 according to the following AOCS official methods: AOCS Cd 3d-63, AOCS Cd 3-25, AOCS Cd 8b-90, AOCS Cd-1.25, and AOCS 940.28 [42], Refraction Index by adjusting the Abbé Refractometer with distilled water (IR 20 ºC = 1.333), density at 313 K, viscosity according to ASTM 446 and ASTM D 2515 methods using a Cannon-Fenske viscosim- eter, (Capillary tube Nº. 200) and carotenes by UV-VIS spectrophotometry and HPLC. The fixed bed containing γ-alumina loaded with Buriti oil has been characterized in terms of height (m), internal diameter (m), adsorbent equilibrium capacity (g/kg), particle diameter (A), particle porosity (-), fixed bed porosity (-), CO2 interstitial velocity (m/s), and adsorbent density (kg/m³). The mass transfer models of Tan and Liou and Brady et.al have been applied to describe the kinetic behavior of supercritical desorption process. The influence of pressure and adsorbent capacity on the supercritical desorption processes has been investigated by analyzing the mass transfer performance. The solubility of Buriti oil in supercritical carbon dioxide has been computed by linear adjust of desorption kinetic by determining the final point of the linear part of desorption/ extraction curve. A computational algorithm code written in EXCEL using the build in function PROJ.LIN has been used to calculate the period of constant extraction rate, the mass transfer rate for the period of constant extraction rate and the solubility. This spreadsheet calculator generates a graphic that shows automatically the splines of both straight lines describing the periods of constant and decreasing extraction rate being adjusted. A 2.5 fold enriching of carotenes has been obtained by integrated supercritical adsorption/desorption of Buriti oil fat soluble compounds in γ-alumina adsorbent using carbon dioxide as solvent, posing this methodology as an alternative method for the enrichment of carotenes from vegetable oils. Carbon Dioxide Capture and Utilisation for Energy Generation and Composite Materials CARBON DIOxIDE CAPTURE AND UTILISATION FOR ENERGy GENERATION AND COMPOSITE MATERIALS

fabricio c. Marques, neil Rowson, peter J. hammond, Regina c. D. santos University of Birmingham; Edgbaston, B15 2TT, Birmingham, West Midlands, UK; E-mail: [email protected]

There is growing agreement that anthropogenic emission of greenhouse gases like carbon dioxide (CO2) have led to global warming and climate change on a global scale, which are having dire consequences for the Earth’s eco- system. Fortunately there are many technologies that can capture CO2. Nevertheless, most processes propose storing it underground, which requires a very large infrastructure that is costly and energy-intensive, not to mention other negative impacts on the environment. In addition large quantities of CO2 can be released back to the atmosphere if naturally-occurring phenomena or accidents occur. As a result, a novel process has been developed in conjunction with industrial partner CCm Research Ltd., where eco-friendly cellulosic-based biomass is functionalised with amine compounds that effectively chemisorb CO2 in an exothermic reaction and convert it to a stable carbonate form (R-CO3). The carbonate structure has been confirmed with FTIR and SEM, and the reaction mechanism and thermal stability of the material have been studied with a simultaneous thermal analyser using a TGA-DTA connected to an FTIR for evolved gas analysis. One application of this material has been tested, where it was compounded in an extruder with polymer to form a strong,

 321 322  SFE 2013 | workshop on supercritical fluids and energy lightweight composite material. The physical and chem- Investigations on Supercritical ical properties of the composite were determined with a Transesterification of mechanical tester, a gas pycnometer and the TGA-DTA- Vegetable Oils and Animal Fats FTIR system. The activation energy for composite decom- for Biodiesel Production at position was generally found to be double that of pure Temperatures 300-400 ºC and polymer, thus resulting in a material with higher thermal 9:1-15:1 Alcohol Molar Ratios stability. Moreover, any CO2 in carbonate form encapsulated within the polymer was only released upon decomposition at temperatures above the composite’s melting point, thus effectively increasing its thermal stability more than twofold. Composites containing high levels of CO2-loaded biomass displayed values of yield stress and elasticity modulus that indicate the composite can be applied in several areas where polymers are commonly used, e.g. packaging, furniture, automobiles, construction, etc. There- fore a method to capture and utilize CO2 was demonstrated, which avoids the high costs and logistics associated with storage underground. This new material is very promising because of its CO2 capture effectiveness, simple production process, low energy consumption and relatively low cost. Ultimately this process is sustainable and can be commercialised, thus generating economic and environmental benefits at the same time. INVESTIGATIONS ON SUPERCRITICAL TRANSESTERIFICATION OF VEGETABLE OILS AND ANIMAL FATS FOR BIODIESEL PRODUCTION AT TEMPERATURES 300-400 ºC AND 9:1-15:1 ALCOhOL MOLAR RATIOS

victor fernando Marulanda Universidad de La Salle; Cra 2 # 10-70, 57, Bogota, Cundinamarca, Colombia; E-mail: [email protected]

Supercritical transesterification has been proposed as an alternative to the conventional base catalyzed process for biodiesel production due to its apparent advantages related to the feasibility to use cheaper triglyceride feedstocks, and a simpler process resulting of the elimination of the use of a catalyst in the final product purification. In this aspect, most of the experimental studies have been carried out at temperatures 300-350 ºC and alcohol to oil molar ratios higher than 40:1, higher temperatures have been associated to a deterioration of the fuel quality. More recently, several studies have been conducted at temperatures around 400 ºC and lower reactant ratios. Though initially focused on improving economic and environmental performance indicators of the supercritical process, the experimental results have shown the high temperature promotes several reactions of decomposition of long chain esters and glycerol into short chain esters and glycerol ethers, which have the potential to improve certain properties of the fuel such as viscosity and cold flow. In this work the experimental results of the batch and continuous supercritical transesterification of chicken fat, bovine fat and crude palm oil with methanol and ethanol at temperatures 300-400 ºC and 9:1-15:1 alcohol molar ratios are

 323 324  SFE 2013 | workshop on supercritical fluids and energy discussed. Qualitative as well as quantitative product anal- Precipitation and ysis by GC-MS indicates a conversion of triglycerides near Encapsulation of to completion at 400 ºC and residence times of 12, 15 and Bioactive compounds Using 30 minutes for chicken fat, crude palm oil and bovine fat, Supercritical Technology respectively. The different times can be associated to the alcohol used in the transesterification, methanol or ethanol, the first one being more reactive, and the triglyceride composition of the raw material. Short chain methyl esters as well as linear hydrocarbons not initially present in the raw material were identified in the produced biodiesel. Though short chain esters have lower boiling points and viscosities than the longer ones, which positively affect the product, the cetane number is lower. However hydrocarbons have a higher cetane number that could make up for the apparent reduction or deterioration of the fuel quality. Glycerol ethers, resulting from methylation/ethylation reactions of glycerol were also identified in the product. Some of these products remained in the biodiesel phase and could act to improve certain properties of the fuel or be considered fuel additives. In this aspect, the studied supercritical process could offer a feasible technical alternative to the glycerol byproduct, currently considered a waste problem for the biodiesel process due to the high cost of its purification and low prices in the market. PRECIPITATION AND ENCAPSULATION OF BIOACTIVE COMPOUNDS USING SUPERCRITICAL TEChNOLOGy

natália Mezzomo, sandra R. s. ferreira Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil; E-mail: [email protected]

Natural products are relevant sources of compounds with biological activity, which are technologically important for employment in chemical, pharmaceutical and food industries. The growing interest of these industries in natural extracts foments researches of their recovery using technologies that allow high quality production. Due to the molecular structure and high unsaturation rate of these compounds, factors like heat, light and presence of acids cause their isomerization, with loss and/or diminution of the biological properties. Thus, aiming at industrial application of these extracts, the study of methods enabling their stabilization, as encapsulation in polymers, is important. The objective of this project is to study the encapsulation of bioactive extracts through the processes of Supercritical Anti-Solvent (SAS) and Supercritical Fluid Extraction of Emulsions (SFEE), seeking the production of stable micro/nano-particles. For both methods application, a flexible unit that can be used for Supercritical Fluid Extraction (SFE), SAS and SFEE is being executed. The evaluation of SAS unit is being performed throughout the precipitation of sodium ibuprofen, a well-known nonste- roidal anti-inflammatory drug considered model material for crystallization processes. The primary solvent used was acetone and the anti-solvent applied was supercritical CO2.

 325 326  SFE 2013 | workshop on supercritical fluids and energy

The following ranges evaluated the SAS process: pressure (80-140 bar), temperature (35-55 ºC ), solute concentration (0.5-1.5 mg/mL), solution flow rate (1-3 mL/min) and constant CO2 flow rate of 1 kg/h. The particles obtained from all conditions were evaluated by their size and morphology, using a scanning electronic microscopy (SEM), the thermal profiles by differential scanning calorimetry (DSC), and the crystallinity using x-ray diffraction (XRD). The average particle sizes of the SAS-precipitated ibuprofen were below 380 ± 84 nm for all the conditions tested in the experiments, which means that the size of the original particles was reduced from micrometric (non-processed sodium ibuprofen) to nanometric order (SAS particles). The best SAS operational conditions, in order to produce the lowest ibuprofen particle size, were 0.5 mg_ibuprofen/mL,

1 mL_solution/min, 1 kg_CO2/h, 110 bar and 35 ºC. Besides reducing the ibuprofen particle size, the SAS process appears to have purified the original sodium ibuprofen, according to the thermal analysis of processed and non- processed ibuprofen particles. The XRD results indicated that SAS process at 1 mg_ibuprofen/mL, 1 mL_solution/min, 1 kg_

CO2/h, 110 bar and 35 ºC are the best conditions to obtain ibuprofen particles with higher crystallinity. The sequence of the project is the SAS study applied to natural extracts encapsulation. It is being studied the SAS encapsulation of extract from grape pomace in poly(lactic-co-glycolic) acid (PLGA), varying the operational variables (pressures of 80-140 bar temperature of 35-45 ºC, solution flow rate of

1-3 mL_solution/min, constant CO2 flow rate of 1 kg_CO2/h), and verifying their influence in the quality of particles produced (particle size and shape by SEM analysis, interaction between encapsulant and encapsulated materials through the DSC). The future project activities are to adjust the SFE/SAS unit to the SFEE process and apply it to natural extracts encapsulation. IDTq — A NEW RESEARCh GROUP LOCATED IN CORDOBA, ARGENTINA: PhASE EqUILIBRIUM AND ITS APPLICATION TO IMPREGNATE BIOPOLyMERS AND TO DESIGN DRUG DELIVERy SySTEMS

Juan M. Milanesio, Alfonsina E. Andreatta* IDTQ – Grupo Vinculado PLAPIQUI – CONICET – FCEFyN, Universidad Nacional de Córdoba; Av. Vélez Sarsﬁ eld 1611, Córdoba, Argentina * Facultad Regional San Francisco, Universidad Tecnológica Nacional; Av. de la Universidad 501, San Francisco, Córdoba, Argentina

cesar gomez, Miriam striumia Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba; Haya de la Torre y Medina Allende, Ediﬁ cio de Ciencias II, Ciudad Universitaria, Córdoba, Argentina

Lidia Quinzani PLAPIQUI – Planta Piloto de Ingeniería Química, Universidad Nacional del Sur – CONICET, Cno.; La Carrindanga km. 7, Bahía Blanca, Argentina; E-mail: [email protected]

IDTQ is a recently developed research group with a high potential and mainly focused on supercritical technology applied to the extraction of natural products and its use on human health, and also applied to solve energy problems. Also, the extracted bioactive compounds are being studied to develop new drug delivery systems using polymers with supercritical technology. The synthesis of polymers from glycerol or its derivatives and their application to develop controlled release drug delivery systems are one of the main interests in our research group. Plants with important properties for human health accompany mankind from its origins. In spite of the great evolution of health sciences, pathologies still exist without

 327 328  SFE 2013 | workshop on supercritical fluids and energy a definitive cure or with therapies that cause undesirable Compressed Gases for the effects. Within this frame it is necessary to search new Separation of Biomass from therapeutic agents. Ionic Liquid Mixtures Glycerol is a polyfunctional molecule, with three alcohol groups and with a high reactivity and versatility [1]. Using esterification reactions it is possible to develop new polymers with surfactant properties [1]. These polymers, with a hydrophilic and a hydrophobic region, can be used for drug encapsulation [2-5] using supercritical technology for particle precipitation [6]. Particularly, they can be used as carriers for highly hydrophobic drugs inside micelles, like cancer chemotherapy drugs [2, 4-5]. In this work we will present preliminary results for the synthesis of polymers via glycerol esterification and from glycerol carbonate, and its application for designing controlled release drug delivery systems. Within the scope of these preliminary results are phase equilibrium data for glycerol, carbon dioxide and the polymers.

References [1] C. H. Zhou, J. N. Beltramini, Y. X. Fan, G. Q. Lu, Chemoselective catalytic conversion of glycerol as a biorenewable source to valuable commodity chemicals, Chemical Society Reviews, 37 (2008) 527-549. [2] M. E. Fox, F. C. Szoka, J. M. J. Fréchet, Soluble polymer carriers for the treatment of cancer: The importance of molecular architecture, Accounts of Chemical Research, 42 (2009) 1141-1151. [3] J. Green, Z. Tyrrell, M. Radosz, Micellization of poly(ethylene glycol)- block-poly(caprolactone) in compressible near critical solvents, J. Phys- ical Chemistry C, 114 (2010) 16082-16086. [4] L. Y. Lee, S. H. Ranganath, Y. Fu, J. L. Zheng, H. S. Lee, C. H. Wang, K. A. Smith, Paclitaxel release from micro-porous PLGA disks, Chem- ical Engineering Science, 64 (2009) 4341-4349. [5] Z. L. Tyrrell, Y. Shen, M. Radosz, Multilayered nanoparticles for controlled release of paclitaxel formed by near-critical micellization of tri- block copolymers, Macromol, 45 (2012) 4809-4817. [6] S. D. Yeo, E. Kiran, Formation of polymer particles with supercritical fluids: A review, J. Supercritical Fluids, 34 (2005) 287-308. COMPRESSED GASES FOR ThE SEPARATION OF BIOMASS FROM IONIC LIqUID MIxTURES

David L. Minnick, Aaron M. scurto Department of Chemical & Petroleum Engineering and Center for Environmentally Beneﬁ cial Catalysis, University of Kansas; 5234 Eisenhower Terrace, 66049, Lawrence, Kansas, USA; E-mail: [email protected]

Identifying cost-effective renewable energy sources is vital as the world continues to experience a strain on fossil fuels. Cellulose, the world’s most abundant natural biopolymer, presents an inexpensive, carbon-neutral feedstock for the production of bio-fuels and bio-chemicals. Howev- er, the rigid hydrogen bonding network between cellulose molecules renders it insoluble in nearly all organic solvents. Select ionic liquids (ILs) including 1-butyl-3-methylimidazolium chloride [BMIm][Cl] and 1-ethyl-3-methylimidazolium diethyl phosphate [EMIm][DEP] are capable of dissolving significant quantities of cellulose. Once dissolved the cellulose can undergo one of two routes: 1) direct conversion to glucose via hydrolysis or 2) precipitation. In the first process, cellulose derivatization results in monomeric glucose subunits that can be used for energy, or further processed into high-value chemicals. Alternatively, precipitating the cellulose out of the IL yields a less-crystalline, pre-processed form with a wide range of applications. Regardless of the desired end product, an extraction technique must be performed to separate the final product and ionic liquid. Anti- solvent methods have been proposed whereby large quantities of anti-solvent are mixed with the IL solution to crystallize the product, resulting in solid-liquid phase

 329 330  SFE 2013 | workshop on supercritical fluids and energy equilibria (SLE). While effective, the excessive quantities Obtaining extracts from clove of anti-solvent required to separate cellulose and glucose (Eugenia caryophyllus) and from ionic liquids negatively impacts the feasibility of these annatto (Bixa Orellana L.) using processes from sustainability and economic standpoints. supercritical fluid extraction in Here we propose a competing process to selectively re- a continuous operating mode move cellulose and glucose from ionic liquids using compressed CO2 by altering the phase behavior of these systems. For the IL:glucose system, two extraction methods have been observed. First, CO2 at moderate pressure is capable of converting this system from vapor-liquid equilibria (VLE) to vapor-liquid-solid equilibria (VLSE) phase behavior, thus precipitating the pure glucose product for separation by filtration. Second, high pressure CO2 can transform certain IL/glucose/solvent systems from vapor-liquid equilibria (VLE) to vapor-liquid-liquid equilibria (VLLE) phase behavior where glucose is extracted into the organic or aqueous (non-IL) liquid phase for separation. These same processes are applicable to the separation of cellulose from ILs and will be demonstrated. Compressed carbon dioxide is a promising alternative to conventional organic anti-solvents for extracting glucose and cellulose from ionic liquids. Our results will display how high pressure CO2 can alter the phase behavior of these systems and the resulting glucose/cellulose separations. OBTAINING ExTRACTS FROM CLOVE (EugEniA cARyophyLLus) AND ANNATTO (BixA oRELLAnA L.) USING SUPERCRITICAL FLUID ExTRACTION IN A CONTINUOUS OPERATING MODE

Moyses n. Moraes, giovani L. Zabot, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

The goal of obtaining increasingly natural products of high purity is leading researchers to use more suitable extraction processes, known as “green processes”. Thus, supercritical fluid extraction (SFE) is receiving increased attention, because it is a green technology that yields distinct extracts relative to those obtained in the conventional extraction processes. The resulting SFE waste, which is considered a better co-product, is the vegetal matrix, free of target compounds; the matrix can be used as the raw material for other integrated processes. The maximum utilization of raw materials is a current subject in interest. Likewise, the productivity of a process can be improved by incorporating the continuous extraction of bioactive compounds. Understanding the influence of various parameters on the continuous extraction process is the target for implementing the supercritical technology on an industrial scale. The extraction time, the amount of solvent, the shape of the extractors and the characteristics of the raw materials are some of the parameters known to influence the techno- economic aspects of such processes. Further, the use of a range of extraction vessels is necessary to accomplish the operation. In this sense, we assembled an apparatus with two one-liter extractors to obtain two extracts in continu-

 331 332  SFE 2013 | workshop on supercritical fluids and energy

ous mode using supercritical CO2, including (1) a volatile Estimation of Costs in oil from clove buds and (2) an extract rich in tocotrienols Supercritical CO2 Extraction from annatto seeds. These two vegetal matrices were se- Plants of Solid Substrates by lected because they contain volatile oil and pigments with Simulation Process health benefits, which are in high demand in the global market. The high quantity of bixin in the annatto extracts allows for strong colorant action. Additionally, both raw materials can be used, after extraction, in the hydrolysis of the lignocellulosic structure for producing fermentable sugars. In this context, the proposed system was found to be efficient because it was possible to reach significant extraction yields in short times in comparison to batch processes. When one extractor was in the charge/discharge step, the other was used for extraction, which allowed the product to be continuously obtained. Based on laboratory experiments, some parameters were defined as suitable parameters for use in the continuous mode. For clove oil

(1), the ideal CO2 mass to feed mass (S/F) was approximately 1.9 (corresponding to 60 min of extraction and 80 g of extract/100 g of extractable). For the annatto extract (2), the ideal S/F was approximately 2.7 (corresponding to 90 min of extraction and 66 g of extract/100 g of extractable). From the economic perspective, the use of supercritical

CO2 extraction in a continuous mode reduces the payback, which is the time needed to match the net profit with the initial amount of capital invested.

Acknowledgements The authors acknowledge the financial support from CAPES (DEA/FEA/ PROEX); partial support from FAPESP (2009/17234-9 and 2012/10685-8) is also acknowledged. M. N. Moraes thanks CAPES and G. L. Zabot thanks FAPESP (2011/23665-2) for the Ph.D. assistantships. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1). ESTIMATION OF COSTS IN

SUPERCRITICAL CO2 ExTRACTION PLANTS OF SOLID SUBSTRATES By SIMULATION PROCESS

gonzalo A. núñez, José M. del valle Universidad Técnica Federico Santa María; Av. Vicuña Mackenna 3939 San Joaquín, Santiago, Chile; E-mail: [email protected]

Supercritical fluid extraction of solid substrates has been applied commercially for a long time to several applications (including extraction of hops, decaffeination of coffee beans, extraction of flavors from herbs and spices, extraction of oilseed, among others). Despite of this, in literature there is little information about scaling-up and costing of this technology, which generally is part of the know-how of plant manufacturers. The objective of this work (based on the doctoral thesis titled “Development of a Simulation Tool for the Economic Optimization of an Extraction Plant for Vegetable Substrates Using Supercritical CO2”) is to present a simulation tool to estimate the costs in an industrial supercritical CO2 extraction plant and to show the effect of relevant parameters in the extraction process. Particularly, this work presents estimates for operational and production costs of the supercritical CO2 extraction of prepressed oilseeds using a novel simulation algorithm based on the fully predictive shrinking core model for the inner mass transfer. Operational costs (<9 USD/kg of oil) decrease when particle size decreases and superficial CO2 velocity increases. Production costs (estimated <13 USD/ kg of oil) include the capital cost, which is one of the items with major uncertainties in the estimates. Under the same extraction conditions, a decreasing of the aspect ratio (L/D)

 333 334  SFE 2013 | workshop on supercritical fluids and energy of the extraction vessels has a positive effect on production Overview of the High Pressure cost. In two-vessel plant, the lowest production cost was Technology and Natural reached at highest extraction pressure (70 MPa). However, Products Laboratory of the in multi-vessel plants, the minimum production cost was University of São Paulo in at 50 MPa. In all cases studied, the number of extraction defense of the technological vessels and the total volume of the plant had a positive innovation effect on production cost, confirming that economies of scale apply to this process. Other factors as optimal extraction time, exhaustion grade of the substrate, and productivity of the plant should be taken in count to make decisions about investment or to optimize the operation of an industrial plant. Finally, the methodology developed in the thesis can be adapted to others solid substrates using a proper mass transfer model. This work will present the adaptation of the simulation tool to the extraction of tomato with supercritical CO2 using the Desorption-Dis- solution-Diffusion (DDD) mass transfer model with a Fre- undlich isotherm to describe the partition of the solute between the solid matrix and the supercritical phase. OVERVIEW OF ThE hIGh PRESSURE TEChNOLOGy AND NATURAL PRODUCTS LABORATORy OF ThE UNIVERSITy OF SãO PAULO IN DEFENSE OF ThE TEChNOLOGICAL INNOVATION

Alessandra L. oliveira Departamento de Engenharia de Alimentos (ZEA), Faculdade de Zootecnia e Engenharia de Alimentos (FZEA); Avenida Duque de Caxias Norte, 225, 13635-900, Pirassununga, SP, Brazil; E-mail: [email protected]

The High Pressure Technology and Natural Products Lab- oratory (LTAPPN ) is a new research laboratory of the Food Engineering Department, Faculty of Animal Science and Food Engineering of the University of São Paulo. Created in 2003 under the responsibility of Prof. Dr. A.L. Oliveira, it conducts physical separations research employing high- pressure systems. Initial work was aimed to study the separation extracts rich in active compounds from natural Brazilian flora (Guaco, Pitanga fruit) using supercritical

CO2 and thermodynamic modeling of the solubility of these compounds in this supercritical solvent using equations of state. Currently, the work continues to be developed for this purpose, using separation processes with supercritical fluid (SFE) and pressurized liquid extraction (PLE) with pressurization by means of nitrogen. The modeling of separation processes continues to be practiced using equations of state for the solubility study and numerical simulation in transport phenomena. Research are directed to extraction optimization of Pitanga seeds, flour from Babaçu mesocarp and Pequi, characteristic fruit from Bra- zilian Cerrado using SFE and PFE. These studies aim to demonstrate that technological innovation is able to get

 335 336  SFE 2013 | workshop on supercritical fluids and energy these extracts with efficiency and quality when consider the maintenance of their activities. Specifically for eucalyptus oil, it is noteworthy that Brazil is the world’s largest exporter. However, the extraction method is rudimentary and this disqualifies it regarding the decomposition of its main compound due to high temperatures employed in the process. The study of the supercritical extraction optimization, another work in progress in LTAPPN, allowed to achieve high yields of essential oil rich in citronellal and a second product, the oil resin, rich in phenol compounds with high antioxidant activity. This oil resin is an unknown product for the producers of eucalyptus essential oil in Brazil. The high-pressure processes are also being used in the pretreatment of lignocellulosic waste material to be employed in enzymatic processes aimed for sugar production from sugar cane bagasse for ethanol manufacture or xylose from coconut fiber. The appeal of this technology application is linked to supply clean raw materials and consequently without contaminants that negatively inter- fere in the enzymatic process. The oil from green coffee beans is one of the main subjects of study in this laboratory. In this research development there is a French insti- tution collaboration (ICOA, Université d’Orléans). This study aims to enrich the green coffee oil with its main diterpenes (cafestol and kahweol) with chemoprotective action. In this laboratory is also developed research using fish waste from Brazilian industry, studying conditions for enrichment of shark liver oil in its main component, the squalene with several biological activities. The LTAPPN has ten graduate students with instruction in different knowledge domains, which makes it possible to perform researches in collaboration with other international and Brazilian laboratories aiming for the application of these extracts for specific purposes as medicine action. For example, the used of Posters  337

Pitanga seeds extract against leishmaniasis and the study in vivo of green coffee oil chemoprotective action. The most recent research line investigated in LTAPPN directs to the microencapsulation of natural extracts, volatile or not, using Rapid Expansion of Supercritical Solution (RESS) system using polymers of low commercial value. Sensory analysis is also a common subject in this laboratory works since it is used as a tool for evaluating the aromatic volatile compounds quality in the extraction or encapsulation process. The LTAPPN aims to contribute in demonstrating that technological innovation can be feasible if the research results might increase some extracts value by new extraction methodology or even by the fractionation possibility and consequent enrichment in active compounds. Regarding the interaction University/Company, the LTAPPN has collaboration or/and development with some companies as Ingredion Brazil, O Boticário and SPF Palatability Brazil. Supercritical technology applied to the reuse of passion fruit residue SUPERCRITICAL TEChNOLOGy APPLIED TO ThE REUSE OF PASSION FRUIT RESIDUE

Daniela Alves de oliveira, sandra R. s. ferreira Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil; E-mail: [email protected]

The passion fruit juice production engenders a large amount of residues such as seeds and rind. Despite the current efforts from companies to reuse process residues, large amounts of passion fruit seeds are still underutilized by the industries. Part of it has been used to produce seed oil, due to its high content of unsaturated fatty acids, especially linoleic acid (up to 70%) finding various applications in the food, pharmaceutical and cosmetic industries. Still, in the residue of the cold press oil production — the seed cake — remains fatty acids, phenolic compounds and proteins of interest. Phenolic compounds are known to possess biological activities but due to the molecular structure and high unsaturation rate of these compounds, factors like heat and light can cause loss and/or diminution of their biological properties. The literature reports the antioxidant and antitumor activities of the passion fruit seed oil or from specific compounds present in the oil, but few studies are found concerning the supercritical technology to obtain passion fruit oil and/or biologically active derivatives. Thus, the study of methods enabling the extraction of interest compounds from passion fruit seeds and their stabilization, as precipitation and encapsulation with polymers, may add value to this residue. The present study aims: (a) to apply the supercritical fluid extraction

 339 340  SFE 2013 | workshop on supercritical fluids and energy

(SFE) on passion fruit seeds and seed cake and compare The extraction, micronization it to two different extraction techniques by evaluating their and encapsulation of performances in terms of process yield, total phenolic con- curcuminoids from turmeric tent (TPC), antioxidant activity (AA) and composition of (Cúrcuma longa L.) using extracts; (b) based on previous results, to select one of the pressurized liquids and supercritical extracts to perform phase equilibrium exper- supercritical fluids iments to determine a range of operational conditions to be employed on precipitation/encapsulation assays. Ex- traction methods used were: supercritical fluid extraction

(SFE) with CO2 (scCO2), conducted at 40 °C and 50 °C with pressures of 150 and 250 bar and 0.5 kgCO2/h; and the low pressure techniques (LPE) of cold maceration (MAC) and ultrasonic assisted extraction (UE) using different organic solvents. The best yield results were obtained by SFE at 250 bar and 40 °C for the seed (27 ± 1%) and by MAC with 50% ethanol for cake (6 ± 1%). The cake UE performed with 50% ethanol presented the highest TPC result determined by the Folin-Ciocalteau method (336 ± 22 mggallic acid equivalents/gextract) and the best AA using the β-carotene bleaching method (88.8 ± 0% AA after 120 min). The precipitation/encapsulation of bioactive extracts with poly(lactic-co-glycolic) acid (PLGA) will be done through the processes of Supercritical Anti-Solvent (SAS) and Supercritical Fluid Extraction of Emulsions (SFEE) varying the operational variables and verifying their influence in the quality of particles produced, seeking the production of stable micro/nanoparticles. For both precipitation/encapsulation methods, a flexible unit that can be used for SFE, SAS and SFEE is being adapted. The particles obtained from all conditions will be evaluated by their size and morphology, using a scanning electronic microscopy (SEM), by the interaction between encapsulant and encapsulated materials through the thermal profiles using differential scanning calorimetry (DSC), and their crystallinity using x-ray diffraction (XRD). ThE ExTRACTION, MICRONIzATION AND ENCAPSULATION OF CURCUMINOIDS FROM TURMERIC (cúRcuMA LongA L.) USING PRESSURIzED LIqUIDS AND SUPERCRITICAL FLUIDS

Juan f. osorio Tobón, Mauricio A. Rostagno, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

The turmeric (Cúrcuma longa L.) plant is widely cultivat- ed in countries and regions with tropical and subtropical climates. Turmeric has been used since ancient times as a condiment, preservative, flavoring, coloring agent and folk medicine [1]. Turmeric has been investigated for its biological activity in association with anticancer, antibacterial, chemopreventive and chemotherapeutic properties. Today, turmeric is used mainly as a dye, due to the interest of replacing synthetic additives with natural compounds [2]. The yellow color of the rhizomes is due to the presence of a group of phenolic compounds called curcuminoids. There are three main curcuminoids, including curcumin (I), demethoxycurcumin (II) and bisdemethoxycurcumin (III). Curcuminoids have traditionally been extracted by liquid-liquid extraction and Soxhlet. Today, the need to develop more efficient processes and avoid the use of organic solvents has facilitated the development of more rapid and environmentally friendly techniques, such as pressurized liquid extraction (PLE). PLE is performed under a wide range of conditions with a compressed liquid. In this region, the liquids are

 341 342  SFE 2013 | workshop on supercritical fluids and energy highly incompressible, and when the solvents are subjected to pressure changes at constant temperature, the solvent density and solvation power are insignificantly affected [3]. However, the use of increased temperatures improves the efficiency of extraction due to the enhanced rate of mass transfer and diffusion rates [4]. Several techniques are used for the production of micro-particles, such as spray-drying, spray-cooling and spray-chilling; however, these methods possess several disadvantages, such as product degradation, contamina- tion with organic solvents and the production of large-size particles [5]. For this reason, supercritical antisolvent precipitation (SAS) and supercritical fluid extraction of emulsions (SFEE) have been proposed as alternatives to the conventional micronization techniques. In the SAS process, a liquid solution containing the solute to be micronized is brought into contact with a supercritical fluid (SCF). Therefore, the contact between the liquid solution and the SCF induces the formation of a solution, producing the condition of supersaturation and causing solute precipitation. Several differences exist between SAS processes and that of SFEE: an emulsion containing the desired substance to be precipitated, which is dissolved in the SFC, is injected instead of injecting a simple solution of the substance, causing the formation of a liquid product. The objective of this work is to develop a PLE process for curcuminoids and to study the micronization and encapsulation of the extracts obtained by PLE through supercritical fluids. To meet this objective, the temperature and pressure effects will be studied relative to the total yield of curcuminoids in the PLE process. To eliminate the organic solvent and produce micro- and nanoparticles, the effects of temperature, pressure and flow on the SAS Posters  343 and the SFEE processes will be evaluated. The curcuminoids will be quantified by HPLC. The morphology and particle size distributions of the micro- and nanoparticles obtained by SAS and SFEE will be acquired using scanning electron microscopy. Precipitation yield and encapsulation efficiency will be determined. The impact of the different factors on the cost of manufacture will be evaluated using SuperPro Designer®.

Acknowledgements Authors are grateful to CNPq (470916/2012-5) for the financial support; partial support from FAPESP (2012/10685-8) is also acknowledged. Juan F. Osorio-Tobón thanks CAPES for the PhD assistantship. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).

REFERENCES [1] C. A. C. Araujo, L. L. Leon, Biological activities of Curcuma longa L., Memorias Do Instituto Oswaldo Cruz, 96 (2001) 723-728. [2] P. N. Ravindran, K. N. Babu, K. Sivaraman, Turmeric: The genus Curcuma, Taylor & Francis, 2007. [3] C. C. Teo, S. N. Tan, J. W. H. Yong, C. S. Hew, E. S. Ong, Pressurized hot water extraction (PHWE), J. Chromatography A, 1217 (2010) 2484- 2494. [4] D. T. Santos, P. C. Veggi, M. A. A. Meireles, Optimization and economic evaluation of pressurized liquid extraction of phenolic compounds from jabuticaba skins, J. Food Engineering, 108 (2012) 444-452. [5] M. J. Cocero, A. Martin, F. Mattea, S. Varona, Encapsulation and co- precipitation processes with supercritical fluids: Fundamentals and applications, J. Supercritical Fluids, 47 (2009) 546-555. Molecular Thermodynamics Analysis of Biofuel Systems MOLECULAR ThERMODyNAMICS ANALySIS OF BIOFUEL SySTEMS

c. g. pereira, n. ferrando, p. Mougin, J. c. hemptinne DEQ/CT/UFRN – Federal University of Rio Grande do Norte; Av. Sen. Salgado Filho, 3000 Cidade Universitária, 59078-970, Natal, RN, Brazil; E-mail: [email protected]

Thermodynamics has an important role in several industrial sectors, representing the basis in the development of projects, products as well as in the simulation steps and process optimization. Thermodynamic equations and models are used as a tool to support operational decisions. Over the years, the industry challenge has been to understand the behavior of different systems to improve a process or to obtain a particular product. Nonetheless, the focus changes according to the interests of each area. Nowadays, the necessity of the environmental preservation and the requirements from the government, agencies and society for the use of sustainable products and processes has driven the search for new technologies. Since fuel originating from biomass becomes a real alternative for petroleum fuel and started to be commercially produced several studies has been done in order to understand the systems involved in its processing. Biodiesel is a renewable, biodegradable and environmentally correct substitute to mineral diesel, produced through the transesterification reaction of triglycerides with any short-chain alcohol, such as methanol or ethanol. The result of this reaction is a mixture of ethyl or methyl esters of fatty acids (biodiesel) and glycerol. Recent studies have also considered supercritical

 345 346  SFE 2013 | workshop on supercritical fluids and energy or compressed fluids as alternative routes for the separation and purification steps of biodiesel. When dealing with separation units the knowledge of the phase equilibria is essential to evaluate systems in real processing conditions. In statistical thermodynamics, the properties of a bulk system are determined based on the interactions between the molecules constituting the system. The detailed molecular interactions (repulsive and attractive) within complex fluids can be evaluated by the three categories of equations of state (cubic, lattice and perturbation). The analysis of intermolecular forces present in the system represents a fundamental role in the understanding and application of these models. Among the perturbation theories, SAFT (Statistical Associating Fluid Theory) is increasingly used. This EoS explicits in the equation terms related to the effect of dispersion, chain formation and association in the molecule. Several variations of SAFT were derived from the original model [1] (CK-SAFT, PC- SAFT, SAFT-VR, others). The GC-PPC-SAFT (Group Con- tribution Polar Perturbed-Chain — SAFT) combines a group contribution method [2] with the PC-SAFT EOS [3] and an additional polar contribution. It has demonstrated good results for different classes of compounds such as esters, ethers, ketones, alcohols, amines, aromatic/polyaromatic compounds, and their mixtures. Concerning additional predictive models, Molecular Simulation has also been successful in calculating properties of complex systems. More specifically, the Monte Carlo simulation technique has been successfully used to predict phase equilibria of systems of industrial interest. The present work presents a predictive analysis of phase equilibrium of systems involved in the biofuel processing. The experimental data from literature were compared with predicted values using GC-PPC-SAFT, PSRK equations of state and molecular simulation. Pre- Posters  347 dictive multiphase equilibria was computed for the systems: alcohol (ethanol or methanol) + ethyl or methyl esters; alcohol + glycerol; biofuel blends. The predicted values showed to be consistent with new experimental data.

References [1] M.S. Wertheim, J. Statistical Physics, 35 (1986) 35. [2] S. Tamouza, J.P. Passarello, P. Tobaly, J.C. de Hemptinne, Fluid Phase Equilibria, 222 (2004) 67. [3] J. Gross, G. Sadowski. Industrial & Engineering Chemistry Research, 40 (2001) 1244. Pilot plant concept for hydrogen generation by biomass gasification in supercritical water integrated with a thermoelectric unit

(h2-bgscw/teu) PILOT PLANT CONCEPT FOR hyDROGEN GENERATION By BIOMASS GASIFICATION IN SUPERCRITICAL wATER INTEGRATED WITh A ThERMOELECTRIC UNIT

(h2-BGSCW/TEU)

Daltro garcia pinatti, Rosa Ana conte Departamento de Engenharia de Materiais, Escola de Engenharia de Lorena, USP; Polo Urbo-Industrial, s/no., Gleba AI-6, Bairro Santa Lucrécia, 12602-810, Lorena, SP, Brazil; E-mails: [email protected]; [email protected] hydrothermal processing in supercritical water (SCW) has many advantages over steam [1]: complete sterilization of pathogens, three regions of hydrothermal process (liquefaction, catalytic reforming/ gasification, and high temperature gasification), properties variation of water (density, solvation power, gas miscibility, and salt crystallization), biomass drying is unnecessary, high versatility of chemistry, enhancement of reaction rates and efficient separation, and SCW does not have phase transitions. After decades of development SCW is a great success in coal-fired thermoelectric units (TEU) [2] due to the use of ppb-purity water and Benson boiler. Partial or total replacement of coal by biomass pellets is under development. SCW applied to other fields is hindered by a number of problems: corrosion, incrustation, creep at 25 MPa/700 oC, materials cost, low concentration of biomass and large water volumes, among others. H2-BGSCW/TEU concept developed by DEMAR-EEL-USP [3,4] is facing those problems with the following interdisciplinary approaches: (a) functional separation of materials (FSM) using high performance con- crete (HPC, 90 MPa) with addition of rice husk silica to

 349 350  SFE 2013 | workshop on supercritical fluids and energy increase compression resistance, GPa-steel cables to support tensile strength at room temperature, and castable refractory for thermal insulation of the pressure vessel; (b) inside the pressure vessel the reaction tank, heat exchangers and piping are made of thin wall superaustenitic steels, working at small pressure differences between their walls at 650 oC; (c) components inside the pressure vessel are mechanically supported at the bottom at room temperature and they are free for thermal expansion at the top; (d)

H2-BGSCW reactor is installed between TEU SCW boiler and turbine; (e) slurry prepared with 5 wt% of clean biomass with addition of activated carbon as catalyst for high rate H2 production [5]; (f) electric energy hydrostorage (EEHS) after the first expansion (H2 release) at 12.5 MPa during 19 hours of the day, and expansion in Pelton hydroturbines at peak hours (3 hours of the day). The last technology covers the cost of circulation of large volumes of water in the H2-BGSCW/TEU. The pilot plant concept maximizes yield of high valued products, minimizes material and capital investments, utilizes the full capacity of SCW technology, and faces up the operational reality of the H2-BGSCW unit. H2-BGSCW/TEU aims a medium size power plant

(50 MWe, 1300 kg H2/hr.) to be installed in a distributed way to incentivize reforestation, nucleation of industrial complexes, generation of employment, revenues and taxes.

REFERENCES [1] A. A. Peterson et al., Thermochemical biofuel production in hydrothermal media: A review of sub- and supercritical water technologies, En- ergy Environmental Science, 1 (2008) 32–65. [2] T. Jäntti, H. Lampenius, M. Ruuskanen, R. Parkkonen, Supercritical OUT CFB Projects-Lagisza 460 MWe and Novercherkasskays 330 MWe, Russia Power Moscow, Russia March 28-30, (2011) TP_CFB_11_04. [3] D. G. Pinatti, R. A. Conte, Total integration of renewable and fossil energy aiming to a clean and sustainable energy system, J. Energy and Power Engineering, 7 (2013) 58-65. Posters  351

[4] D. G. Pinatti, R. A. Conte, Scrutiny of available and new technologies for total integration of renewable and fossil energy for a clean and sustainable energy system- TIRFE. In: Congress of Bioenergy, April 25-28, 2012, Xi’an, China. [5] M. J. Antal Jr., S. G. Allen, D. Schulman, X. Xu, Biomass gasification in supercritical water, Industrial & Engineering Chemistry Research, 39 (2000) 4040-4053.

 353 354  SFE 2013 | workshop on supercritical fluids and energy Posters  355 Modeling of Supercritical Water Oxidation: Hydrothermal Flames as Heat Source MODELING OF SUPERCRITICAL WATER OxIDATION: hyDROThERMAL FLAMES AS hEAT SOURCE

João paulo silva Queiroz, Maria Dolores Bermejo, Maria José cocero Departamento de Ingeniería Química y Tecnología de Medio Ambiente, Universidad de Valladolid; Calle Doctor Mergelina, s/n. 47011, Valladolid, Spain; E-mail: [email protected]

Supercritical water oxidation (SCWO) is a useful technology for the destruction of waste with residence times lower than one minute. It takes advantage of the special solvation properties of water above its critical point (374 ºC, 22.1 MPa) to achieve the complete destruction of organic waste. Oxidation of organics dissolved in supercritical water can be carried out in a homogeneous phase due to the complete miscibility of gases (O2, N2, CO2) and organics with supercritical water. Due to these advantages SCWO has been also proposed as a technology for replacing combustion in power generation [1,2]. However, some challenges have still to be overcome for the successful and profitable commercialization of this technology: corrosion, salt deposition and high energetic demand [3]. Corrosion and salt deposition problems, as well as heat recovery optimization can be avoided by the use of appropriate materials and reactor designs. The application of reactors working with a hydrothermal flame as a heat source con- tributes to overcome many of the challenges present in supercritical water oxidation technology. Injection of the reagents over a hydrothermal flame can avoid preheating problems, such as plugging and corrosion, since the feed

 357 358  SFE 2013 | workshop on supercritical fluids and energy can be injected at lower temperatures (even room temperature). Also the kinetics is much faster allowing complete destructions of the pollutants in residence times lower than 1 s. Next to this, the high temperatures associated to the hydrothermal flames contribute to a better energy recovery of the reaction heat for shaft work production. For safety and material limitations the flame has to be properly in- sulated or kept in distance from the pressure vessel wall. The configuration of the reactor and fluid injection nozzle has to be specially projected for this purpose. Computa- tional fluid dynamics (CFD) is an essential tool for understanding the behavior of actual SCWO reactors and for predicting the efficiency of new designs. In this work, the SCWO process is studied through modeling and simulation:

Methods of estimation for thermal and transport properties of supercritical water and mixtures are studied.

A new global reaction rate for the oxidation of iso- propyl alcohol in hydrothermal regime is adjusted from temperature profiles experimental data. This kinetic model is applied in a parametric analysis of flame formation, and it is used to analyze the behavior of a supercritical water oxidation vessel reactors. The kinetic model is able to describe the behavior of the vessel reactor when working in steady state hydrothermal flame regime at subcritical injection temperatures. The model predicts both flameless and hydrothermal flame regimes.

The influence of the internal configuration of vessel reactors for the Supercritical Water Oxidation Pro- cess is evaluated by simulation and compared to experimental data. The CFD-model developed pro- Posters  359

vides a good prediction of the experimental results and can be used for designing reactors working under hydrothermal flame looking at performance and flame stabilization. Geometrical and operational parameters are studied.

Different turbulence-chemistry interaction theories are tested.

The energetic possibilities of the process are analyzed through calculations. Heat integration, generation of high pressure steam and generation of electricity by products expansion, are feasible in SCWO.

REFERENCES [1] M. Bermejo, M. Cocero, F. Fernandez-Polanco, A process for generating power from the oxidation of coal in supercritical water, Fuel, 83(2) (2004) 195-204. [2] F. Donatini, G. Gigliucci, J. Riccardi, M. Schiavetti, R. Gabbrielli, S. Briola, Supercritical water oxidation of coal in power plants with low

CO2 emissions, Energy, 34(12) (2009) 2144-2150. [3] G. Brunner, Near and supercritical water. part II: oxidative processes, J. Supercritical Fluids, 47(3) (2009) 382-390. The development of integrated systems for the analysis of bioactive compounds in natural products employing supercritical technology ThE DEVELOPMENT OF INTEGRATED SySTEMS FOR ThE ANALySIS OF BIOACTIVE COMPOUNDS IN NATURAL PRODUCTS EMPLOyING SUPERCRITICAL TEChNOLOGy

Mauricio A. Rostagno, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

The increasing evidence that certain compounds present in natural products may be useful for the prevention and treatment of important diseases (such as cancer and cardiovascular diseases) is prompting the development of new processes for the production of high-added-value extracts that are rich in these bioactive compounds. This research line is focused on the investigation of advanced processes for the production of high-value-added extracts based on the combination/coupling of modern techniques in all stages of production, including the pretreatment of the raw material, extraction, purification, solvent evaporation, formation of micro/nanoparticles and encapsulation of the particles formed. The processes developed make use of ultrasound and/or microwave in pre-treatment, a combination of supercritical fluid extraction (SFE) or pressurized liquids (PLE) with ultrasound (UASFE and UAPLE) for the extrac tion of bioactive compounds from the raw material, solid phase extraction (SPE) and chromatography (HPLC or SFC) for the purification of crude extracts obtained in the processing line and supercritical antisolvent process (SAS) or supercritical fluid extraction from emulsion process (SFEE), also used in line to eliminate the use of organic solvents

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/ the formation of micro/nano particles and encapsulation. The high efficiency of these integrated and combined systems and the associated processes allows for the exploration of “green” solvents, such as water, ethanol and supercritical carbon dioxide, as replacements of the traditionally used toxic solvents, which include methanol and petroleum ether. Further, using the systems developed, it is possible to explore these “green” solvents sequentially for the selective extraction of different components from the same raw material. In the same context, the concept of integrating the different stages of the process and combining the techniques is applied at an analytical scale. Obtaining information regarding the concentrations and profiles of bioactive compounds in natural products is fundamental and has many applications, ranging from bioactivity studies of functional food and drugs to the control of the production process. In this field, research is focused on the development of highly efficient and fast analysis systems that encom- pass these same techniques, consisting of coupling between the sample preparation (extraction and purification) and chromatographic analysis steps. Sample preparation is accomplished through a combination of SFE or PLE using ultrasound (UASFE and UAPLE) and on-line coupling with the purification by SPE, which in turn also is coupled on-line with chromatography analysis (HPLC or SFC). The design of the integrated system allows different procedures to be performed for the extraction, purification and analysis steps (UAPLE; UASFE; SPE; SFC) or as a single on-line process (UAPLE/UASFE -SPE, SPE-SFC; UAPLE / UASFE-SPE-SFC). In addition to the priority given to “green” solvents, another key aspect of this technique is sample output. To reduce the analysis time, new stationary phases are ex- Posters  363 plored (fused-core particles and monolithic columns) in conjunction with the use of relatively high column temperatures and flow rates (at the analytical scale). Due to the high efficiency of these new stationary phases, it is possible to reduce the column dimensions, thereby reducing the analysis time and solvent consumption. These advanced systems are mainly used for the development of “green” methods for the analysis of a wide variety of bioactive compounds (catechins, flavonoids, isoflavones, alkaloids, curcuminoids, carotenoids and ecdysteroids), which is present in different types of samples (tea, coffee, soy- beans, mushrooms, among other natural products). Besides focusing on the development of integrated systems and the methods/processes for the analysis/production of bioactive compounds from natural products, this research also addresses the economic aspects of these technologies through simulations in which the impacts of different factors on the cost of production and analysis are evaluated. Nanostructured Composites of Silica Aerogels with Hydroxy-Terminated Poly(dimethylsiloxane) (PDMS(OH)) by Reactive Supercritical Deposition NANOSTRUCTURED COMPOSITES OF SILICA AEROGELS WITh hyDROxy-TERMINATED POLy(DIMEThyLSILOxANE) (PDMS(Oh)) By REACTIVE SUPERCRITICAL DEPOSITION

Deniz sanli, can Erkey Koc University; Rumeli Feneri Yolu, Koc University Lojmanlar 17/3, Sariyer, 34450, Istanbul, Turkey; E-mail: [email protected], [email protected]

Vacuum insulation panels (VIPs) with typical thermal conductivities of 3 to 5 mW/mK are emerging as alternative systems for effective thermal insulation in buildings and in household appliances. The achievement of such low thermal conductivities in VIPs relies on the suppression of the gaseous conduction by applying vacuum. A VIP is composed of a core insulation material encased in an en- velope film. Among different materials, fumed silica and glass fiber are the most commonly utilized core materials owing to their appreciably low thermal conductivity values, especially under vacuum conditions. Current VIPs are not transparent since neither the core materials nor the envelopes are transparent. However, transparent VIPs can be attractive alternatives for insulation of certain parts of buildings in certain climates. Development of transparent VIPs requires the development of transparent core materials and barrier films. Silica aerogels appear as the most promising nanostructured materials to be implemented as filler materials in transparent VIPs due to their transparency in addition to their low thermal conductivity. One drawback of silica aerogels is their poor mechanical properties and this problem can perhaps be overcome by rein-

 365 366  SFE 2013 | workshop on supercritical fluids and energy forcing aerogels with polymers. In this study, monolithic The Design of a Future composites of silica aerogels with hydroxyl-terminated Biorefinery Based on the Use poly(dimethylsiloxane) (PDMS(OH)) were developed using of Sub/Supercritical Fluids a reactive supercritical deposition technique. The tech- Using Nontraditional Biomass: nique is composed of two stages; the first stage includes Brazilian Ginseng Case Study the dissolution of PDMS(OH) in supercritical CO2 that results in a single phase binary mixture of PDMS(OH)-CO2 and the second stage is the exposure of the silica aerogel samples to the single phase binary mixture. Initially, the demixing pressures of PDMS(OH)-CO2 binary mixtures at various compositions were measured up to 24 MPa to determine the single phase region of the binary mixture. The demixing pressures were observed to decrease with increasing polymer content of the binary mixture. Subsequent- ly, deposition experiments were performed with various PDMS(OH) concentrations and monolithic aerogel composites were obtained. The polymer uptake of the deposited aerogels increased with increasing PDMS(OH) concentration. It was found that the transparency of the aerogels can be controlled by the amount of the polymer loaded to the samples. The deposited samples were characterized by ATR-FTIR and BET analysis. It was revealed that during the course of the deposition, the polymer molecules react with the surface –OH groups of the aerogel. The volume of the polymer in the composites was correlated with the decrease in the pore volume from the BET results. It was demonstrated that the deposition resulted in the coating of silica aerogel surface with a thin layer (~1-2 nm) of polymer. acknowledgments We acknowledge the Financial Support of the NANOINSULATE “Devel- opment of nanotechnology-based High-performance Opaque & Transparent Insulation Systems for Energy-efficient Buildings Project” being funded by the EU Program EeB.NMP.2010-1. ThE DESIGN OF A FUTURE BIOREFINERy BASED ON ThE USE OF SUB/SUPERCRITICAL FLUIDS USING NONTRADITIONAL BIOMASS: BRAzILIAN GINSENG CASE STUDy

Diego T. santos, Renata vardanega, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Diego T. santos, Juliana Q. Albarelli, Adriano v. Ensinas, françois Maréchal Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL); Station 9, CH-1015, Lausanne, Switzerland

The refinery concept applies to the full use of biomass, employing physical and/or chemical treatments for the production of several commercial products of higher added value. The sugarcane industry in Brazil, according to some experts, is only a pioneer for future “biorefineries”. The growing number of technologies under development to produce different products with high added value, such as plant extracts, ethanol and other chemicals, from biomass represents an important aspect that must be thoroughly analyzed, especially from the economic point of view. The use of environmentally friendly sub/supercritical fluid technologies to obtain products from biomass has shown encouraging results. However, studies on the attainment of multiple products in an integrated system, which combines different and sequential processes with the use of multiple fluids, are essential for the implementation of future biorefineries. The main goal of this project is to use the knowledge and tools available for the energy integration, life cycle analysis and multi-objective opti-

 367 368  SFE 2013 | workshop on supercritical fluids and energy mization of LENISYSTEM/LENI/EPFL (Switzerland) to evaluate and optimize the production routes using sub/ supercritical fluids developed experimentally in LASEFI/ DEA/FEA/UNICAMP (Brazil), seeking an integral use of all parts of Brazilian ginseng (root and aerial parts). There- fore, it is expected to design a Brazilian ginseng biorefinery based on the use of sub/supercritical fluids. Simulations of the integrated processes were carried out using the commercial simulators SuperPro Designer® and Aspen Plus. Equipment modifications were implemented for the development of new processes and/or combined processes, extending the operational field of LASEFI. Two novel on-line processes were already developed, including:

a) A process for the pressurized hot organic solvent extraction of antioxidants from plants as well as extract precipitation with or without the use of a carrier material in one-step. This process has been called OEPO for Organic solvent Extraction and Particle formation On-line. Using this process, different products (precipitated extract, co-precipitated extract or encapsulated extract in suspension) with a very low residual organic solvent concentration (< 50 ppm) can be obtained directly from plant

materials, employing supercritical CO2 as the antisolvent for organic solvent elimination. The OEPO process consists of hyphenated Pressurized Liquid Extraction (PLE)-Supercritical Anti Solvent (SAS) precipitation, PLE-SAS co-precipitation and PLE- Supercritical Fluid Extraction of Emulsions (SFEE). The OEPO processes were successfully developed using Brazilian ginseng roots (Pfaffia glomerata) as a model case. Posters  369

b) A process for the one-step production of emulsions containing essential oils from saponin-rich pressurized aqueous plant extracts was developed. Named by our research group as Emulsion from Pressurized Liquid Extraction (EPLE), the feasibility of this process was demonstrated under optimal PLE conditions (12 MPa), including a temperature of 393 K (120 ºC) and 10 min of static time, using Brazilian ginseng roots as the source of the saponin-rich extract, water as the extracting solvent and clove essential oil as the model dispersed phase.

Therefore, it seems that the best route for the use of the Brazilian ginseng roots is the co-production of an extract rich in beta-ecdysone (antioxidant compound), an extract rich in compounds with surfactant properties and hydrolysates rich in fermentable sugars. To use the Bra- zilian Ginseng aerial parts, a similar approach is under evaluation. After sub/supercritical water hydrolysis of both raw materials solid residues are formed; accordingly, one possible conversion process is the evaluation is the production of synthetic natural gas (SNG) through supercritical water gasification. In a broad sense, we also are concerned with the integration of the proposed Brazilian ginseng biorefinery to the sugarcane industry.

Acknowledgments FAPESP (2010/16485-5; 2012/19304-7; 2012/10685-8) and CNPq.

UTILIzATION OF CARBON DIOxIDE IN ThE ALGAL BIOREFINERy

Lindsay soh Department of Chemical and Biomolecular Engineering, Lafayette College; Easton, PA, USA; Email: [email protected]

Julie B. Zimmerman Department of Chemical and Environmental Engineering, Yale University; New Haven, CT, USA School of Forestry and Environmental Studies, Yale University; New Haven, CT, USA

The imminence of peak oil has implications not only for the security of our energy future, but also our dependence on petrochemicals. The use of petroleum as a feedstock for the production of fuels, plastics, solvents, and other commodities is rampant and vital in our society. The decreasing supply of petroleum requires the need for renewable, alternative feedstocks for the production of fuels and petrochemicals. Due to their fast growth, efficient use of sunlight, and ability to be grown in varied environments, microalgae have sparked great interest in terms of their viability to as a renewable feedstock. When considering algae as a potential feedstock, the chemical fractions that are present must be evaluated, processed, and utilized effectively. In this work, cultivation of different microalgae species under varied growth conditions was undertaken in order to characterize differences in biomass, lipid, protein, and starch productivity. The results were used to inform a combinatorial life cycle as-

 371 372  SFE 2013 | workshop on supercritical fluids and energy sessment, which highlights the need and ability to optimize and tailor algal species and cultivation conditions for a specific endpoint. Additionally, efficient processing must be developed in order to harvest, separate, and convert the different chemical fractions efficiently. Within this context, supercritical carbon dioxide

(scCO2), a green solvent, has great potential towards the efficient processing of algal biomass as a whole. Not only is scCO2 considered green compared to other solvents, but it also has selective and tunable solvent properties and is easy to separate from end-products. In this work the use of scCO2 for the efficient extraction and conversion of algal lipids into biodiesel is explored with further implications for processing within the context of a biorefinery.

scCO2 was shown to be an effective solvent for the selective extraction of lipids from algal biomass. The selectivity of scCO2 can be further exploited in order to harvest other value-added co-products such as carotenoids or phospholipids. As a result of the clean extraction process, the remaining biomass can be utilized for further processing to harvest other products such as protein or starch for a variety of applications such as animal feed, further fuel production, or even the production of high value commodities. While the lipid fraction may have valuable use as a chemical feedstock, its utilization in the production of fuels is of great interest to create direct, drop-in replacements for our current requirements. The further use of dense CO2 as a medium for conversion of lipids into biodiesel was also researched. In combination with a heterogeneous catalyst, the successful transesterification of triglycerides into fatty acid methyl esters was shown using

CO2 and methanol. In addition to aiding in the successful conversion of triglycerides into biodiesel, the process offers Posters  373 benefits in terms of selectivity during conversion. Develop- ment of downstream technologies and intelligent processing of biomass are necessary to for the viable, economical, and sustainable use of algae as a renewable feedstock. Equilibrium partition of solutes between supercritical carbon dioxide and vegetable substrates EqUILIBRIUM PARTITION OF SOLUTES BETwEEN SUPERCRITICAL CARBON DIOxIDE AND VEGETABLE SUBSTRATES

freddy A. urrego, José M. del valle Fraunhofer Chile Research; Avenida Mariano Sánchez Fontecilla 310, Piso 14, Las Condes, 7550296, Santiago de Chile, Región Metropolitana, Chile; E-mail: [email protected]

The equilibrium partition of an extractable solute between a solid (vegetable matrix) and a solvent [supercritical CO2

(scCO2)] is one of the limiting factors to the mass transfer in the extraction with supercritical fluids (EFS). By studying how this process works, one may enhance the precision and adaptability of mathematical models applied to the EFS, making them more reliable tools in the simulation of industrial-scale applications based on laboratory- or pilot-plant-scale extraction results. We developed two experimental methodologies to measure the equilibrium partition, and studied different solute-vegetable matrix systems (oil-prepressed rapeseed, capsanthin-extruded + milled red pepper, and lycopene-extruded + milled tomato). The first methodology intersperses equilibration (by continuous recirculation of scCO2 through a cell containing the vegetable matrix) and extraction steps (mainly a static methodology), it was applied to all the systems previously mentioned. The second methodology is based on chromatographic principles, where solute diluted in scCO2 is continuously injected to a column packed with completely scCO2-extracted substrate, and isotherm/isobar curves are calculated from dilution profiles read at the exit of the column with a UV/Vis detector (dynamic methodology), it

 375 376  SFE 2013 | workshop on supercritical fluids and energy was only applied to the lycopene-extruded + milled to- The intensification of the mato system. The operation conditions were between 40- process saponin extraction 67 °C and 22-28 MPa. Different mathematical functions from Brazilian ginseng (Langmuir, Freundlich, Sip’s) were studied, and after mod- (Pfaffia glomerata) using ification and adaptation of the Sip’s isotherm, authors pro- ultrasound and hyphenized posed a new isotherm/isobar function. The oil-prepressed processes for integral plant use rapeseed system was best-fitted with the del Valle-Urrego function, whereas the capsanthin-extruded + milled red pepper, and lycopene-extruded + milled tomato systems were best-fitted with the Freundlich function. Based on the results obtained with the mainly static methodology, its results are considered closer to the physical reality, and are therefore used as a comparison base. The dynamic methodology proved to be inadequate to the studied system, because lycopene was not so strongly re-adsorbed onto the vegetable matrix, which led to an isotherm/isobar curve with almost no affinity of lycopene for the solid substrate. From these studies authors concluded that it is necessary to measure and model isotherm/isobar curves in order to improve the precision of mathematical models, and furthermore, to count on calculated parameters values that are more related to the physical reality. ThE INTENSIFICATION OF ThE PROCESS SAPONIN ExTRACTION FROM BRAzILIAN GINSENG (pfAffiA gLoMERATA) USING ULTRASOUND AND hyPhENIzED PROCESSES FOR INTEGRAL PLANT USE

Renata vardanega, Diego T. santos*, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected] *Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL); Station 9, CH-1015, Lausanne, Switzerland

Until recently, the biorefinery concept has been explored as a possibility for sustainable processing with the reduced consumption of energy from fossil fuels. The term biorefinery is applied to the integral use of biomass for the production of high-added-value products with minimal residue generation using sustainable technologies, such as sub- and supercritical fluids. Sub- and supercritical waters have several application possibilities, ranging from extraction to reactions, because they can act as both a benign solvent and catalyst. Sub- and supercritical waters also can be used to extract substances that cannot be obtained under normal temperature and pressure conditions; additionally, these solvents decompose natural biopolymers (cellulose, protein, starch) to produce valuable compounds. To increase the revenues from a given raw material, coproducts in the form of valuable phytochemicals can be extracted prior to performing hydrolysis either at the biorefinery site or at a site of close proximity. Brazilian ginseng (Pfaffia glomerata) is a commercialized substitute for ginseng

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(Panax) due to its similar morphology and therapeutic effects. This plant has a large content of saponins, which can be used as a natural surfactant. Moreover, the residue from the extraction process is a good source of polysaccharides. Therefore, this residue can be used to produce several molecules, among them, second-generation ethanol. Considering the potential of this raw material and the new trends in terms of the development of green technologies for the production of different products from the same raw material, the possibility of the integral use of Brazilian ginseng is very promising. Pressurized fluid technologies have become very interesting options and are the focus of this research. First, we intend to develop an intensified method that includes the use of sequential extractions to obtain distinct products of high-added-value in each step, namely, extractions of saponins followed by residue hydrolysis to produce fermentable sugars. After, using the commercial software SuperPro Designer, the economic viability of the process will be evaluated, and the process will be simulated using ultrasound to increase the yield of extraction and, thus, the productivity of the process. Additionally, the possibility of coupling a purification process, such as supercritical anti-solvent extrac tion, will be evaluated; the aim is to obtain high-quality extracts using fewer steps than conventional processes. Some preliminary results have shown that it is possible to obtain extracts that are rich in bioactive compounds and that possess emulsification properties from both the roots and aerial parts of Brazilian ginseng by applying different processing conditions in terms of the type of solvent used and the processing temperature. Moreover, we have identified that it is possible to obtain simple sugars by hydrolyz- ing the residue from the extraction process of the Brazilian ginseng roots. Additionally, collaborative works have been Posters  379 developed with colleagues on studies of the hydrolysis of agricultural and food residues for the production of simple sugars using sub- and supercritical water assisted by supercritical CO2. The hydrolysates obtained can be converted into second-generation bioethanol by fermentation.

Acknowledgements The authors acknowledge the financial support from CAPES (DEA/FEA/ PROEX); partial support from FAPESP (2009/17234-9 and 2012/10685-8) is also acknowledged. R. Vardanega thanks CNPq (140282/2013-0) for the Ph.D. assistantship. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1). SFE technology for poorly defined oligomeric mixtures SFE TEChNOLOGy FOR POORLy DEFINED OLIGOMERIC MIxTURES

Julian velez, David f. Esguerra, Mark c. Thies Department of Chemical and Biomolecular Engineering, Center for Advanced Engineering Fibers and Films, Clemson University; Clemson, SC 29634, USA; E-mail: [email protected]

Our research is focused on the use of supercritical (SC) fluids to fractionate and characterize oligomeric carbonaceous pitches, potential precursors for advanced carbon materials. In particular, we are performing semi-continuous SC extraction experiments, investigating both SC toluene and SC toluene/N-methyl-2-pyrrolidone (NMP) mixtures as extractive solvents for fractionating a catalytically produced pyrene pitch into its constituent oligomers. Although neat supercritical toluene (Tc = 318.6 °C; Pc = 41.1 bar) has been shown to be an effective solvent for the recovery of both monomer and dimer species in high purities, higher- oligomer solubilities in toluene are notoriously low. The addition of NMP as a co-solvent enhances oligomeric solubilities in the extractive, supercritical-solvent phase by a factor of 3, making possible the recovery of trimer and higher oligomers. In addition, it also suppresses the undesired, AlCl3-aided reactions that occur in the column between the pyrene oligomers and toluene by forming

Lewis acid-base complexes with the AlCl3 catalyst. A supercritical co-solvent mixture consisting of 15 mol % NMP in supercritical toluene was found to be an effective solvent system for recovering pyrene dimer and trimer cuts at purities exceeding 99%. These cuts exhibit dramatically

 381 382  SFE 2013 | workshop on supercritical fluids and energy different properties from the starting mixture once they The influence of bed are isolated: for instance, the trimer fraction is found to geometry on the kinetics of form a liquid-crystalline phase (i.e., mesophase) which is the extraction of vegetal not observed in either the starting mixture or the dimer compounds with supercritical fraction. CO and biomass hydrolysis A significant advantage of the use of SC extraction 2 technology in this work is that the high-purity pitch oligomers isolated via SC extraction can serve as excellent feedstocks for a variety of analytical characterization techniques. For example, molecular-structure information on the individual species comprising both the starting pitch and the oligomeric cuts is obtained when these high-purity fractions are further fractionated by liquid chromatography methods (e.g., GPC, HPLC) and/or analyzed with techniques such as MALDI Mass Spectrometry and UV-Vis and Fluorescence spectroscopy, etc. By using such a sequential separation technique (i.e., SC extraction followed by analytical separation), the species comprising the pyrene monomer and dimer fractions have been unambiguously identified and their concentrations in the starting material determined. These results show the potential of SC fluid extraction technology for the molecular characterization and quantification of poorly defined, oligomeric and polymeric mixtures, with applications in both biomass and heavy fossil fuel conversion. ThE INFLUENCE OF BED GEOMETRy ON ThE KINETICS OF ThE ExTRACTION OF VEGETAL COMPOUNDS WITh SUPERCRITICAL

CO2 AND BIOMASS hyDROLySIS

giovani L. Zabot, Moyses n. Moraes, M. Angela A. Meireles LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]

Natural substances extracted from plants present particular properties that are distinct from the properties of synthetic substances and are useful in the formulation of bioproducts, as well as in the pharmaceutical field. Novel extraction techniques, such as the use of supercritical fluids, are acquiring notoriety by providing the selective extraction of bioactive compounds with high quality. In the field of supercritical technology, investigations are performed to increase the quantitative and qualitative yield by changing the processing conditions (i.e., pressure, temperature). However, it is necessary to discriminate further the influence of other variables, such as the bed geometry. Thus, the aim of this work is to evaluate the use of supercritical CO2 extraction from the technical and economic perspectives in obtaining compounds from clove and rosemary by using laboratory equipment that possesses 2 one-liter extractors with different height (HB) to bed diameter (DB) ratios. The first and second steps of the thesis work consisted of the assembly of this SFE-2×1L equipment and in the characterization of the raw materials, respectively. The third step was the evaluation of the temperature profiles inside the beds, with the goal of selecting the time for static process and defining the external con-

 383 384  SFE 2013 | workshop on supercritical fluids and energy ditions for the extractor temperatures. The fourth step was to compare the kinetic parameters obtained by adjusting the extraction curves for both geometries (E-1: HB/DB = 7.1;

E-2: HB/DB = 2.7). Two criteria for scale-up were used. The first criterion consisted of maintaining equal interstitial solvent velocities in both geometries, which was not suitable for the process. The second consisted of maintaining constant mass of solvent to mass of feed ratios (S/F) and extraction times. This criterion was appropriate for this process due to the similar mass transfer rates used in comparison to the commercial Spe-ed equipment (Applied Sep arations, 7071, Allentown, USA), which has a 0.1 L extractor

(E-3; HB/DB = 3.9). Nonetheless, the bed E-2 presented global yields slightly superior in comparison to E-1, mainly due to the excessive compaction observed in E-1. This behavior was even more pronounced when rosemary was used. As Laurent et al. [1] reported for the decaffeination of coffee beans with a particle size of approximately 7 mm, large HB/DB ratios (approximately 9) should be used. How- ever, for smaller particles in the range of 0.4-0.8 mm, which tend to swell, the HB/DB ratio should be 3. Using this information in our study, in which the particle average sizes were 0.76 mm and 0.66 mm for clove and rosemary, respectively, we conclude that the yield in E-1 (HB/DB = 7.1) was influenced by significant compaction and CO2 chan- neling, which resulted in large axial dispersions of the solvent-solute. These phenomena were most likely small in E-2 (HB/DB = 2.7). The selection of either E-2 or E-1 as the convenient extractor also depends on studies of the economic feasibility of the process, because low HB/DB ratios influence the construction costs of the extractors. Thus, in the next step, the cost of manufacturing will be simulated at different scales and geometries, including a continuous operation mode. Further, process integration Posters  385 is a recent trend that displays several applications in the supercritical technology field. In this sense, the biomass from extraction will be used to hydrolyze the lignocellulosic material, with the objective of obtaining high-added-value substances.

Acknowledgements The authors acknowledge the financial support from CAPES (DEA/FEA/ PROEX); partial support from FAPESP (2009/17234-9 and 2012/10685-8) is also acknowledged. G. L. Zabot thanks FAPESP (2011/23665-2) and M. N. Moraes thanks CAPES for the Ph.D. assistantships. M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).

References [1] A. Laurent, E. Lack, T. Gamse, R. Marr, Separation operations and equipment, in: A.V.G. Bertucco (Ed.) High pressure process technology: fundamentals and applications, Elsevier, Amsterdam; New York, 2001, pp. 351-403.

INDEx

Albarelli, Juliana Q. 237, 367 Debien, Isabel C. N. 289 Albuquerque, Carolina L. C. 245 Devor, Robert 303 Albuquerque, Flávio C. 195, 261 Dias, Ana M. A. 265, 293 Alcázar-Alay, Sylvia C. 249 Domínguez, Herminia 253 Anderson, Mark 89 Elizondo, Elisa 61 Andreatta, Alfonsina E. 251, 327 Ensinas, Adriano V. 237, 367 Araújo, M. E. 317 Erkey, Can 53, 365 Azevedo, Evelin C. 257 Escorsin, Alexis M. 125 Azevedo, F. F. M. 317 Esguerra, David F. 221, 381 Balboa, Elena M. 253 Fages, Jacques 147 Baskette, Rudy 275 Farías-Campomanes, Angela M. 253 Batista, C. F. M. 317 Farouk, Bakhtier 213 Bazito, Reinaldo 179 Ferrando, N. 345 Benelli, Patícia 257 Ferreira, Sandra Regina Salvador 65, Benezet, Jean-Charles 147 257, 287, 325, 339 Bermejo, Maria Dolores 357 Ferrer, Lidia 61 Berni, Mauro 297 Fornari, Tiziana 229 Bisaia, Rodrigo 261 Forster-Carneiro, Tania 233, 249, 273, 297 Bochon, I. 189 Francisco, María 71 Bolaños, Gustavo 79 Frerich, Sulamith 239 Borges, Endler Marcel 261 Braga, Mara E. M. 265, 293 Ge, Zhiwei 305 Brennecke, Joan F. 269 Gomes, M. Thereza M. S. 301 Bruinhorst, Adriaan van den 71 Gomez, Cesar 327 Brunner, Gerd 21 Goto, Motonobu 95 Grandelli, Heather E. 303 Cabral, Marcos Vinícius Riscado 195 Guo, Liejin 203, 305 Cabrera, Ingrid 61 Guo, Simao 305 Canales, Roberto 269 Cardenas-Toro, Fiorela P. 273 Hammond, Peter J. 321 Carneiro, Cristiana B. 297 Hasan, Nusair 213 Carpanedo, Thayane 275 Hegel, P. 121 Carvalho, Pedro Ivo N. de 277 Hemptinne, J. C. 345 Chan, Yi Herng 177 Hijazi, Nibal 147 Chiavone-Filho, Osvaldo 281 Hintze, Paul E. 303 Ciftci, Ozan Nazim 217, 285 Hodes, Marc 135 Cocero, Maria José 45, 117, 357 Hrnčič, M. Knez 113 Comim, Sibele R. Rosso 257, 287 Huddle, Thomas 209 Conte, Rosa Ana 349 Iannace, S. 139 Corazza, Marcos L. 125 Ibáñez, E. 169 Córdoba, Alba 61 James, Kenneth J. 275 Cotabarren, N. 121 Jesus, Susana P. 307 Crone, M. 131 Jin, Hui 305, 311 Cunha, M. A. E. 317 Jr., Richard L. Smith 35 Dahmen, Nicolaus 107 Jr., Valdir F. Veiga 253

 387 388  SFE 2013 | workshop on supercritical fluids and energy

Kanda, Hideki 95 Queiroz, João Paulo Silva 357 King, Jerry W. 29 Quinzani, Lidia 327 Kiran, Erdogan 155 Quispe-Condori, Socrates 173 Kitchens, Christopher L. 165 Rajab, Ahmad 111 Knez, Ž. 113 Ravber, M. 113 Kroon, Maaike C. 71 Rocha, Sandro R. P. da 143 Kruse, Andrea 41 Rodier, Elisabeth 147 Lu, Youjun 305, 313 Rojas, Paula 61 Machado, N. T. 317 Romão, Guilherme 261 Maio, E. Di 139 Rostagno, Mauricio A. 261, 277, 341, 361 Maloney, Phillip 303 Rowson, Neil 321 Maréchal, François 237, 367 Sala, Santi 61 Markočič, E. 113 Saldaña, Marleny D. A. 183 Marosi, Gyorgy 147 Sanli, Deniz 365 Marques, Fabricio C. 321 Santana, A. L. 317 Martínez, Julian 225 Santos, Diego T. 301, 367, 377 Martini, Raquel E. 251 Santos, Regina C. D. 127, 321 Marulanda, Victor Fernando 323 Sauceau, Martial 147 Meireles, M. Angela A. 195, 233, 237, Scofield, Arthur de Lemos 195 245, 249, 253, 261, 273, 277, 289, Scott, Adam 221 297, 301, 307, 331, 341, 361, 367, Scurto, Aaron M. 77, 329 377, 383 Škerget, M. 113 Meredith, Carson 151 Smirnova, Irina 51 Mezzomo, Natália 287, 325 Soh, Lindsay 371 Mićić, Vladan 177 Sousa, Hermínio C. de 265, 293 Milanesio, Juan M. 251, 327 Spilsbury, Christopher G. 193 Minnick, David L. 329 Striumia, Miriam 327 Moigne, Nicolas Le 147 Subramaniam, Bala 57 Moraes, Moyses N. 331, 383 Sunol, Aydin K. 199 Moreno, Evelyn 61 Surma, Jan 303 Mougin, P. 345 Takahashi, Shinya 155 Müller, S. 131 Teja, Amyn S. 161 Muntó, María 61 Temelli, Feral 217, 285 Nagy, Zsombor 147 Thies, Mark C. 221, 381 Ndiaye, Papa M. 125 Timko, Michael T. 105 Netti, P. A. 139 Tobón, Juan F. Osorio 341 Núñez, Gonzalo A. 333 Türk, M. 131 Oliveira, Alessandra L. 335 Uemura, Yoshimitsu 111 Oliveira, Daniela Alves de 339 Urrego, Freddy A. 375 Oliveira, José Vladimir de 207, 287 Valle, José M. del 93, 333, 375 Omar, Wissam 111 Vardanega, Renata 367, 377 Orsi, S. 139 Vazquez, M. F. Barrera 251 Osman, Noridah 111 Veciana, Jaume 61 Pedrosa, Rozangela C. 257 Vega, Lourdes F. 25 Pereda, S. 121 Velez, Julian 221, 381 Pereira, Carlos V. Lamarão 253 Ventosa, Nora 61 Pereira, C. G. 345 Vigh, Tamás 147 Pessoa, Fernando Luiz Pellegrini 281 Weidner, Eckhard 99 Petermann, Marcus 189, 239 Peters, Cor J. 71 Wei, Liping 313 Pinatti, Daltro Garcia 349 Yusup, Suzana 111, 177 Pioro, Igor 85 Zabot, Giovani L. 331, 383 Prado, Juliana M. 233, 297 Zheng, Pengfei 313 Proença, Thaís A. 287 Zimmerman, Julie B. 371 Queiroz, Eduardo Mach 281 Zubeir, Lawien F. 71