DOCSLIB.ORG

Generalized Model for Predicting Methane Conversion to Syngas in Membrane Reactor

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Generalized Model for Predicting Methane Conversion to Syngas in Membrane Reactor INTERNATIONAL JOURNAL OF MultiCraft International Journal of Engineering, Science and Technology ENGINEERING, Vol. 8, No. 4, 2016, pp. 8-15 SCIENCE AND TECHNOLOGY www.ijest-ng.com www.ajol.info/index.php/ijest 2016 MultiCraft Limited. All rights reserved Generalized model for predicting methane conversion to syngas in membrane reactor Rachna Sinha, Garima Chauhan* University School of Chemical Technology, Guru Gobind Singh Indraprastha University, New Delhi-110078, INDIA *Corresponding Author: e-mail: (Garima Chauhan) [email protected] Abstract Present work aims to provide a conceptual framework for predicting methane conversion efficiency and CO selectivity in a membrane reactor which may assist in selecting the type of membrane and minimizing the cost of syngas production. A comparative evaluation of the performance of ceramic (inorganic) membrane reactors was carried out with other types of synthetic membrane reactors. Data has been taken only from those research papers in which reactor is operating in a temperature range of 800 – 900ºC and the pressure range is 1-2 atm. Linear regression analysis was performed and a generalized equation was developed to predict the methane conversion and CO selectivity using different types of membranes. Simulations were performed using MATLAB ODE45 to investigate feasibility of the developed model. CO selectivity was observed better for ceramic membrane reactors since it achieves 90% saturation in 25 hours while for other synthetic membranes, the conversion is only 10% (approx). Overall, ceramic membrane reactors were found to be better than other synthetic membrane reactor due to effective CO selectivity and CH4 conversion. Keywords: Syngas, CH4 conversion, CO selectivity, ceramic membrane DOI: http://dx.doi.org/10.4314/ijest.v8i4.2 1. Introduction Rapid innovations in technologies and fast paced economic development across the globe are foretokens to edify the necessity of sustainable energy resources. Annual Energy Outlook 2012 projected the increase in world energy consumption by 47% from year 2010 to year 2035 (Energy Outlook, 2012). Global population is projected to reach approximately 8.8 billion people by year 2035 and consequently, world GDP is expected to more than double over the same time period (BP Outlook, 2016). Developing countries China and India are expected to drive the world economy by contributing together for almost 50% of the hike in global GDP (BP Outlook, 2016). Though, economic development and technology advancement are requisite for human welfare, it is pragmatically impossible to have economic growth without concomitant consumption of energy resources (Chauhan et al., 2013). Therefore, an urgent need is felt to look for sustainable energy resources which can be exploited as primary energy source. Fossil fuels are being considered significant contributor in global energy supply, however tremendous increase in greenhouse gas emission and onset of climate change are prevalent issues associated with fossil fuel combustion. Several research efforts are being made worldwide to develop novel technologies for the efficient utilization of renewable energy sources and sequestration of emitted greenhouse gases. Natural gas is being considered the most economically accessible energy resource in present scenario. The ascertained reserves of natural gas amounted world-wide to over 6973 trillion cubic feet (International Energy Statistics, 2015). Call for natural gas is going up by 1.8% per annum which clearly indicates urgent necessity of this fossil fuel. Emerging economies (China and India) account for approximately 30% of the increase in natural gas demand for industrial utilization and power generation (BP Outlook, 2016). Extensive research efforts have been riveted on up-gradation of natural gas to value-added products. Conversion of natural gas to liquid fuels (GTL) through a syngas intermediate (CO/H2) is one of the major research streams in order to conserve the energy 9 Sinha and Chauhan / International Journal of Engineering, Science and Technology, Vol. 8, No. 4, 2016, pp. 8-15 resources. Three possible pathways (steam Reforming, dry reforming and partial oxidation of methane) may be adopted for the natural gas to liquid fuel conversion during GTL process. Steam reforming process (CH4 + steam → CO + H2), being an endothermic process, requires extensive energy supply. Also, poor selectivity for CO and high H2/CO product ratio are the major limitations which make it unsuitable for industrial applications. Dry reforming process (CH4 + CO2 → CO + H2) utilizes the carbon dioxide gas and thus can reduce the greenhouse gas emission, however thermodynamic constraints associated with the process limit conversion efficiency and increases the economics of the process (Gallucci et al., 2008). Partial oxidation of methane (POM) (CH4 + O2 → CO + H2) over the supported transition metals is gaining attention these days due to higher reaction rate, more favourable H2/CO ratio and mild exo-thermicity of the reaction (Wei et al., 2011). Several studies have been reported to identify novel catalysts for syngas production using POM pathway (Sharifnia and Karami, 2015; Wei et al., 2016), however, most of the catalysts for syngas synthesis are active at high temperatures (> 973 K). Secondly, consumption of significant quantities of expensive pure oxygen during POM and the cost associated with the production of pure O2 using cryogenic air separators are added limitations which affect economics of the process. Aforementioned limitations associated with available technologies elucidate the need of an innovative sustainable process for syngas production. Membrane reactors with oxygen semipermeable ionic (or mixed) conducting dense ceramic membranes have drawn considerable attention in last few decades due to their ability to carry out simultaneous reaction and separation (Tong et al., 2006; Silva et al., 2015; Rui et al., 2008). Broadly categorizing, the available membrane reactors can be divided under two categories i.e. ceramic (inorganic) membrane reactors and Organic/metallic/liquid membrane reactors. In the present study, all other synthetically prepared membranes except ceramic membranes are denoted as synthetic membrane reactor. Table 1 provides a brief review about the operating parameters and membrane properties employed in synthetic and ceramic membrane reactors. Table 1 : Literature review on ceramic and synthetic membrane reactor Reactor Membrane Operating Parameter Efficiency References Ceramic Membrane Reactors Dual-phase composite 960°C Time dependence of oxygen Zhu et al., 2010 membrane reactors. permeation flux was observed during initial stages Dense BaCo0.7Fe0.2Ta0.1O3−d 900°C CH4 conversion > 99% ; CO Luo et al., 2010 perovskite membrane selectivity : 94% mixed conducting ceramic operating time : 2200 h CH4 conversion > 96% ; CO Tong et al., 2006 membrane reactors. Temp: 900°C selectivity > 95% Pressure: 1-1.2atm Hollow fibre catalytic reactor, perovskite mixed conducting 925°C CO selectivity > 97% ; CH4 Wang et al., 2006 Ni-based catalyst membrane (BaCoxFeyZrzO3-d ) conversion : 96%. Membrane Reactor ceramic composite of Ba0.5Sr0.5 T : 900°C No significant change in CO Chen et al., 2003 Co0.8Fe0.2O 3_d (97.5 mol%) and Pressure : 1 atm selectivity with variation of CH4 Co3O4 (2.5 mol%). feeding rate Tubular reactor (Catalyst : a perovskite material Temperature: 875°C CO selectivity > 95% ; CH4 Wang et al., 2003 LiLaNiO/–Al2O3) Ba0.5Sr0.5Co0.8Fe0.2O3−δ , with Conversion > 94% electronic and ionic conductivity. Catalytic membrane reactor, zirconium-based dense membrane, Temperature : 850°C CH4 conversion : 96–98%; CO Tong et al., 2002 LiLaNiO/γ -Al2O3 catalyst with mixed conducting perovskite selectivity : 98–99% 10wt.% nickel loading (BaCo0.4Fe0.4Zr0.2O3−δ) Catalyst packed tubular reactor Perovskite-type oxide Temperature : 1098- CH4 conversion > 96% ; CO Jin et al., 2000 La0.6Sr0.4Co0.2Fe0.8O3-d 1158 K selectivity > 97% at low carbon space velocity Other Synthetic Membrane Reactors Fixed bed reactor, Ni-based Pd-Ag membrane Temp : 823K, 873 K Hydrogen yield reached 21% at 823 Silva et al., 2015 catalyst Pressure : 1.01×105 Pa K and 47% at 873K Tubular membrane reactors Pd–Ag alloy membrane Temperature ranges 350 Maximum CO2 conversion : 20.6% Gallucci et al., 2008 -450°C. for the MR at 450°C, 5 10 Pa maximum CH4 conversion: 17.41% for the TR at 450°C Tubular reactor, Ni/γ-Al2O3 oxygen-permeable SrFeCo0.5Oy Temperature : 900 °C; Throughput conversion of CH4 : 98%, Fend et al., 2004 catalyst membrane CH4 feeding rate : 26.8 CO selectivity : 98%, H2/CO : 1.8, mL/min syngas generation rate : 16 mL/min/cm2 a conventional reactor (CR) 50μm thick pinhole free Pd-Ag Maximum CH4 conversion : 69% at Gallucci et al., 2004 and a membrane reactor (MR) alloy membrane 450°C a traditional reactor, Membrane composite ceramic palladium Temperature : 250– DPMR showed highest methane Basile and Paturzo, reactor, Ni-based catalyst membrane reactors (CPMR), and a 550°C. conversion: 2001 dense palladium membrane reactor 45.3% at 400°C and 56.2% at 450°C. (DPMR) Traditional and membrane Palladium based membrane Time factor of 4288 gcat Maximum CH4 conversion: 96% Basile et al., 2001 reactor min / mol, p = 1.2 bar using palladium membrane reactor at 550°C 10 Sinha and Chauhan / International Journal of Engineering, Science and Technology, Vol. 8, No. 4, 2016, pp. 8-15 Present study compares a variety of membranes for the conversion of CH4 to syngas. An extensive literature survey has
Load more

Recommended publications
  • Single Membrane Reactor Configuration for Separation of Hydrogen, Carbon Dioxide and Hydrogen Sulfide
    II.C SeparaTioNS II.C.1 Single Membrane Reactor Configuration for Separation of Hydrogen, Carbon Dioxide and Hydrogen Sulfide overall footprint than can be achieved by utilizing Shain J. Doong separate components for each required unit process/unit Gas Technology Institute (GTI) operation. Specifically, research is sought to perform a 1700 South Mount Prospect Road combination of theoretical and experimental research Des Plaines, IL 60018 to provide a scientific basis needed to develop a novel Phone: (847) 768-0884 “one-box” process to combine synthesis gas cleanup, E-mail: [email protected] water-gas shift reaction, hydrogen separation and carbon dioxide separation. A successful strategy will have the DOE Technology Development Manager: potential to selectively remove pure hydrogen, carbon Dan Cicero dioxide and synthesis gas impurities in a single reactor Phone: (412) 386-4826 configuration that can operate simultaneously at high E-mail: [email protected] temperature and high conversion, possibly without the DOE Project Officer: Elaine Everitt requirement of excess steam. Phone: (304) 285-4491 E-mail: [email protected] Approach Contract Number: DE-FC26-05NT42450 The objective of this research is to develop a Start Date: June 2005 “one-box” approach that can consolidate two or Projected End Date: May 2007 more downstream reaction/separation units of a coal gasification system in a single module for production of a pure stream of hydrogen. The project will evaluate the technical feasibility of using two or three types Objectives of membranes to selectively separate pure hydrogen, carbon dioxide and hydrogen sulfide in a single reactor • Develop a novel membrane process concept configuration that can operate simultaneously at high that would combine hydrogen sulfide removal, temperatures (e.g., 700-900ºC).
    [Show full text]
  • Catalytic Membrane Reactors: the Industrial Applications Perspective
    catalysts Review Catalytic Membrane Reactors: The Industrial Applications Perspective Catia Algieri 1,*, Gerardo Coppola 2, Debolina Mukherjee 2, Mahaad Issa Shammas 3, Vincenza Calabro 2 , Stefano Curcio 2 and Sudip Chakraborty 2,* 1 Institute on Membrane Technology, National Research Council of Italy (ITM–CNR), Cubo 17C, Via Pietro Bucci, 87036 Rende, Italy 2 Department of DIMES, University of Calabria, Via Pietro Bucci, Cubo 42A, 87036 Rende, Italy; [email protected] (G.C.); [email protected] (D.M.); [email protected] (V.C.); [email protected] (S.C.) 3 Department of Civil & Environmental Engineering at Dhofar University, Salalah 211, Sultanate of Oman; [email protected] * Correspondence: author: [email protected] (C.A.); [email protected] (S.C.) Abstract: Catalytic membrane reactors have been widely used in different production industries around the world. Applying a catalytic membrane reactor (CMR) reduces waste generation from a cleaner process perspective and reduces energy consumption in line with the process intensification strategy. A CMR combines a chemical or biochemical reaction with a membrane separation process in a single unit by improving the performance of the process in terms of conversion and selectivity. The core of the CMR is the membrane which can be polymeric or inorganic depending on the operating conditions of the catalytic process. Besides, the membrane can be inert or catalytically active. The Citation: Algieri, C.; Coppola, G.; number of studies devoted to applying CMR with higher membrane area per unit volume in multi- Mukherjee, D.; Shammas, M.I.; phase reactions remains very limited for both catalytic polymeric and inorganic membranes.
    [Show full text]
  • Process Intensification with Integrated Water-Gas-Shift Membrane Reactor Reactor Concept (Left)
    INDUSTRIAL TECHNOLOGIES PROGRAM Process Intensification with Integrated Water-Gas-Shift Membrane Reactor Reactor concept (left). Flow diagram (middle): Hydrogen (H2) permeates the membrane where nitrogen (N2) sweeps the gas to Hydrogen-Selective Membranes for High- produce a high-pressure H2/N2 gas stream. Membrane diagram Pressure Hydrogen Separation (right): The H2-selective membrane allows the continuous removal of the H2 produced in the water-gas-shift (WGS) reaction. This allows for the near-complete conversion of carbon monoxide (CO) This project will develop hydrogen-selective membranes for an innovative water-gas-shift reactor that improves gas separation to carbon dioxide (CO2) and for the separation of H2 from CO2. efficiency, enabling reduced energy use and greenhouse gas Image Courtesy of General Electric Company, Western Research Institute, emissions. and Idaho National Laboratory. Benefits for Our Industry and Our Nation Introduction The development of an integrated WGS-MR for hydrogen The goal of process intensification is to reduce the equipment purification and carbon capture will result in fuel flexibility footprint, energy consumption, and environmental impact of as well as environmental, energy, and economic benefits. manufacturing processes. Commercialization of this technology has the potential to achieve the following: One candidate for process intensification is gasification, a common method by which hydrocarbon feedstocks such as coal, • A reduction in energy use during the separation process by biomass, and organic waste are reacted with a controlled amount replacing a conventional WGS reactor and CO2 removal system of oxygen and steam to produce synthesis gas (syngas), which with a WGS-MR and downsized CO2 removal unit is composed primarily of hydrogen (H2) and carbon monoxide (CO).
    [Show full text]
  • Membrane Reactor for Methanol Synthesis Using Si-Rich LTA Zeolite Membrane
    membranes Article Membrane Reactor for Methanol Synthesis Using Si-Rich LTA Zeolite Membrane Masahiro Seshimo 1,*, Bo Liu 1,† , Hey Ryeon Lee 1, Katsunori Yogo 1, Yuichiro Yamaguchi 1,‡, Nobuyuki Shigaki 2, Yasuhiro Mogi 2, Hidetoshi Kita 1,3 and Shin-ichi Nakao 1 1 Inorganic Membranes Research Center, Research Institute of Innovative Technology for the Earth (RITE), 1-7 Hikaridai, Seika-cho, Souraku-gun, Kyoto 619-0237, Japan; [email protected] (B.L.); [email protected] (H.R.L.); [email protected] (K.Y.); [email protected] (Y.Y.); [email protected] (H.K.); [email protected] (S.-i.N.) 2 Steel Research Laboratry, JFE Steel Corporation, 1 Kokan-cho, Fukuyama 721-8510, Japan; [email protected] (N.S.); [email protected] (Y.M.) 3 Environmental Science and Engineering, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611, Japan * Correspondence: [email protected]; Tel.: +81-774-95-5086 † Present address: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China. ‡ Present address: Energy Solution Business Unit, Administration Department, Osaka Gas Co., Ltd., 4-1-2 Hiranomachi, Chuo–ku, Osaka 541-0046, Japan. Abstract: We successfully demonstrated the effect of a membrane reactor for methanol synthesis to improve one-pass CO2 conversion. An Si-rich LTA membrane for dehydration from a methanol synthesis reaction field was synthesized by the seed-assisted hydrothermal synthesis method. The −6 −2 −1 −1 H2O permselective performance of the membrane showed 1.5 × 10 mol m s Pa as H2O permeance and around 2000 as selectivity of H O/MeOH at 473 K.
    [Show full text]
  • Evaluating Hydrogen Production in Biogas Reforming in a Membrane Reactor
    Brazilian Journal of Chemical ISSN 0104-6632 Printed in Brazil Engineering www.abeq.org.br/bjche Vol. 32, No. 01, pp. 201 - 210, January - March, 2015 dx.doi.org/10.1590/0104-6632.20150321s00002820 EVALUATING HYDROGEN PRODUCTION IN BIOGAS REFORMING IN A MEMBRANE REACTOR F. S. A. Silva*, M. Benachour and C. A. M. Abreu Department of Chemical Engineering, Federal University of Pernambuco, CEP: 50740-520, Recife - PE, Brazil. Phone: + (55) (81) 2126-8901 E-mail: [email protected] (Submitted: July 1, 2013 ; Revised: February 25, 2014 ; Accepted: April 29, 2014) Abstract - Syngas and hydrogen production by methane reforming of a biogas (CH4/CO2 = 2.85) using carbon dioxide was evaluated in a fixed bed reactor with a Pd-Ag membrane in the presence of a nickel 5 catalyst (Ni 3.31% weight)/γ-Al2O3) at 773 K, 823 K, and 873 K and 1.01×10 Pa. Operation with hydrogen permeation at 873 K increased the methane conversion to approximately 83% and doubled the hydrogen yield relative to operation without hydrogen permeation. A mathematical model was formulated to predict the evolution of the effluent concentrations. Predictions based on the model showed similar evolutions for yields of hydrogen and carbon monoxide at temperatures below 823 K for operations with and without the hydrogen permeation. The hydrogen yield reached approximately 21% at 823 K and 47% at 873 K under hydrogen permeation conditions. Keywords: Membrane reactor; Biogas; Methane; Syngas; Hydrogen. INTRODUCTION reforming (Kolbitsch et al., 2008; Lau et al., 2011). Biogas is produced from organic household waste, The increasing availability of methane has gener- industrial waste, and animal dung.
    [Show full text]
  • Photocatalytic Membrane Reactors (Pmrs) in Water Treatment: Configurations and Influencing Factors
    catalysts Review Photocatalytic Membrane Reactors (PMRs) in Water Treatment: Configurations and Influencing Factors Xiang Zheng 1, Zhi-Peng Shen 1, Lei Shi 1, Rong Cheng 1,* ID and Dong-Hai Yuan 2,* 1 School of Environment & Natural Resources, Renmin University of China, Beijing 100872, China; [email protected] (X.Z.); [email protected] (Z.-P.S.); [email protected] (L.S.) 2 Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China * Correspondence: [email protected] (R.C.); [email protected] (D.-H.Y.); Tel.: +86-10-8250-2065 (R.C.) Received: 7 June 2017; Accepted: 17 July 2017; Published: 25 July 2017 Abstract: The lack of access to clean water remains a severe issue all over the world. Coupling photocatalysis with the membrane separation process, which is known as a photocatalytic membrane reactor (PMR), is promising for water treatment. PMR has developed rapidly during the last few years, and this paper presents an overview of the progress in the configuration and operational parameters of PMRs. Two main configurations of PMRs (PMRs with immobilized photocatalyst; PMRs with suspended photocatalyst) are comprehensively described and characterized. Various influencing factors on the performance of PMRs, including photocatalyst, light source, water quality, aeration and membrane, are detailed. Moreover, a discussion on the current problems and development prospects of PMRs for practical application are presented. Keywords: heterogeneous photocatalysis; membrane process; photocatalytic membrane reactor (PMR); configuration; influencing factor 1. Introduction With the fast expansion of industrialization and population growth, in addition to increasing water pollution, shortage of clean water sources has turned into a severe problem all over the world.
    [Show full text]
  • Catalytic Solid Oxide Membrane Reactors: Development and Application in the Oxidative Coupling of Methane
    Catalytic Solid Oxide Membrane Reactors: Development and Application in the Oxidative Coupling of Methane by Valentina Omoze Igenegbai A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemical Engineering) in the University of Michigan 2020 Doctoral Committee: Professor Suljo Linic, Chair Professor Erdogan Gulari Professor Melanie Sanford Assistant Professor Nirala Singh Valentina Omoze Igenegbai [email protected] ORCID iD: 0000-0002-2677-005X © Valentina Omoze Igenegbai 2020 Dedication This dissertation is dedicated to my family for their endless love and support. ii Acknowledgements I would like to take this opportunity to acknowledge all those who contributed to the successful completion of my PhD journey. First and foremost, I would like to thank my PhD advisor, Prof. Suljo Linic, for accepting me into his research group and for providing the resources to complete this dissertation work. I am very grateful to him for all the valuable feedback he offered during this work and for providing recommendations in support of my various applications. Thanks to his mentorship, I have grown significantly as a researcher and as an individual. I would also like to thank Prof. Erdogan Gulari, Prof. Melanie Sanford and Prof. Nirala Singh for taking time out of their busy schedules to serve on my dissertation committee and for their useful feedback on my written and oral exams. I have had the pleasure of interacting with these brilliant past and present members of the Linic lab: Brittany Farrell, Paul Hernley, Tim Van Cleve, Matthew Morabito, Calvin Boerigter, Robert Campana, Umar Aslam, Vishal Govind Rao, Joe Quinn, Saman Moniri, Steven Chavez, Sean Dix, John Hemmerling, Rawan Almallahi, Rachel Elias, Jacques Esterhuizen, Ali Motagamwala, James Wortman, Shawn Lu and Aarti Mathur.
    [Show full text]
  • Enzymatic Membrane Reactors: the Determining Factors in Two Separate
    Review Received: 30 August 2010 Revised: 10 December 2010 Accepted: 10 December 2010 Published online in Wiley Online Library: 19 January 2011 (wileyonlinelibrary.com) DOI 10.1002/jctb.2575 Enzymatic membrane reactors: the determining factors in two separate phase operations Joni Agustian,a,b Azlina Harun Kamaruddina∗ and Subhash Bhatiaa Abstract A two separate phase-enzymatic membrane reactor is an attractive process since it has a large interfacial area and exchange surfaces, simultaneous reaction and separation and other benefits. Many factors influence its successful operation, and these include characteristics of the enzyme, membrane, circulating fluids and reactor operations. Although the operating conditions are the main factor, other factors must be considered before, during or after its application. At the initial stage of reactor development, the solubility of substrates and products, type of operation, membrane material and size, enzyme preparation and loading procedure, and cleanliness of the recirculated fluids should be specified. The immobilization site, reactor arrangement, dissolved or no-solvent operation, classic or emulsion operation and immobilized or suspended enzyme(s) are determined later. Some factors still need further studies. Utilization of the technology is described for use from multigram- to plant-scale capacity to process racemic and achiral compounds. The racemates were resolved primarily by kinetic resolution, but dynamic kinetic resolution has been exploited. The technology focused on hydrolytic reactions, but esterification processes were also exploited. c 2011 Society of Chemical Industry Keywords: enzymatic membrane reactors; operational factors; immobilised and suspended enzymes; hydrolysis reactions; esterification; kinetic resolution INTRODUCTION Work on two separate phase-enzymatic membrane reactors Enantiomers of drugs often have different pharmacokinetic and (TSP-EMR or biphasic EMR) were started many years after Rony39 pharmacodynamic properties.
    [Show full text]
  • The Effect of Membranes in Methane Dehydroaromatization
    THE EFFECT OF MEMBRANES IN METHANE DEHYDROAROMATIZATION ON A BIFUNCTIONAL MO/H-ZSM-5 CATALYST IN A PACKED BED REACTOR by Benjamin Lyons Kee c Copyright by Benjamin Lyons Kee, 2016 All Rights Reserved A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Science (Mechan- ical Engineering). Golden, Colorado Date Signed: Benjamin Lyons Kee Signed: Dr. Steven DeCaluwe Thesis Advisor Signed: Dr. Canan Karakaya Thesis Advisor Golden, Colorado Date Signed: Dr. Gregory Jackson Professor and Head Department of Mechanical Engineering ii ABSTRACT Methane is becoming an increasingly attractive resource. Conversion to liquids and higher-value fuels add to the opportunities available for natural gas processes. Conventional methods for converting methane to larger hydrocarbons are through Fischer-Tropsch (F-T), which require multiple unit steps that can add inefficiencies. Methane dehydroaromatization (MDA) is a direct catalytic route to from methane to benzene. Unfortunately, the short- comings of MDA include likelihood to coke and poor yield. Conversion can be increased by removing product hydrogen via a membrane to shift the thermodynamic equilibrium towards the products. A model is developed to study the coupling of hydrogen-selective membranes with packed- bed methane dehydroaromatization (MDA) reactors using bifunctional Mo/H-ZSM-5 cata- lysts. The computational predictions are supported by previously published literature. The effect of hydrogen removal is evaluated as a function of reactor temperature, gas-hourly space velocity (GHSV), and hydrogen removal rate. Consistent with Le Chˆatelier’s principle, the results reveal that membrane integration significantly increases methane conversion.
    [Show full text]
  • Application of Pd-Based Membrane Reactors: an Industrial Perspective
    membranes Article Application of Pd-Based Membrane Reactors: An Industrial Perspective Emma Palo 1, Annarita Salladini 2, Barbara Morico 2, Vincenzo Palma 3, Antonio Ricca 3 and Gaetano Iaquaniello 1,* 1 KT—Kinetics Technology S.p.A., Viale Castello della Magliana 27, 00148 Rome, Italy; [email protected] 2 Processi Innovativi srl, Via di Vannina 88, 00156 Rome, Italy; [email protected] (A.S.); [email protected] (B.M.) 3 Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy; [email protected] (V.P.); [email protected] (A.R.) * Correspondence: [email protected]; Tel.: +39-06-6021-6231 Received: 13 September 2018; Accepted: 23 October 2018; Published: 1 November 2018 Abstract: The development of a chemical industry characterized by resource efficiency, in particular with reference to energy use, is becoming a major issue and driver for the achievement of a sustainable chemical production. From an industrial point of view, several application areas, where energy saving and CO2 emissions still represent a major concern, can take benefit from the application of membrane reactors. On this basis, different markets for membrane reactors are analyzed in this paper, and their technical feasibility is verified by proper experimentation at pilot level relevant to the following processes: (i) pure hydrogen production; (ii) synthetic fuels production; (iii) chemicals production. The main outcomes of operations in the selected research lines are reported and discussed, together with the key obstacles to overcome. Keywords: Pd-based membrane; hydrogen; closed architecture; open architecture; gas to liquid; propylene 1.
    [Show full text]
  • Methanol Synthesis in a High-Pressure Membrane Reactor With
    Methanol synthesis in a high-pressure membrane reactor with liquid sweep Zhongtang Li and Theodore T. Tsotsis* Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, University Park, Los Angeles, CA 90089-1211, United States Keywords: methanol synthesis, membrane reactor, liquid sweep, catalyst, inorganic membrane, membrane surface modification *Corresponding Author Email address: [email protected] 1 ABSTRACT Membrane reactors (MR) are known for their ability to improve the selectivity and yield of chemical reactions. In this paper, a novel high-pressure MR employing a liquid sweep was applied to the methanol synthesis (MeS) reaction, aiming to increase the per single-pass conversion. For carrying-out the reaction, an asymmetric ceramic membrane was modified with a silylating agent in order to render its pore surface hydrophobic. A commercial MeS catalyst was used for the reaction, loaded in the MR shell-side, while the tube-side was swept with a high boiling point organic solvent with high solubility towards methanol. The membrane reactor was studied under a variety of experimental conditions (different pressures, temperatures, space times, and liquid sweep flow rates) and showed improved carbon conversion when compared to the conventional packed-bed reactor operating under the same conditions. 2 1. Introduction A consequence of a growing world population along with continued industrialization, is the increased global demand for energy. Today, fossil fuel resources such as natural gas (NG), crude oil, and coal dominate the world’s energy supply. These traditional energy resources are, however, limited in size, and the fast-growing world population and the booming economies of developing countries such as China and India further intensify concerns about their future availability.
    [Show full text]
  • Oxygen Transport Membranes and Their Role in CO2 Capture And
    ne Scien ra ce b & Riaz and Butt, J Membr Sci Technol 2018, 8:2 m T e e M c h f DOI: 10.4172/2155-9589.1000181 n o o l Journal of Membrane l a o n g r y u ISSN: 2155-9589 o J Science & Technology Review Article Open Access Oxygen Transport Membranes and their Role in CO2 Capture and Syngas Production Muhammad Riaz* and Muhammad Abdullah Butt Department of Chemical Engineering, School of Chemical and Materials Engineering, National University of Science and Technology, Islamabad, Pakistan Abstract Membrane technology for gas separation has seen remarkable improvements in the last 20 years, particularly in the area of air separation for a cost-effective production of highly pure oxygen gas. It is rapidly paving way for alternate route to orthodox separation processes like cryogenic distillation. Solid-state electrochemical cells based on oxygen-ion conduction permit high temperature selective transport of O2 in the form of ionic flux. Hence these systems can act as filters for molecular oxygen either for generation or separation of oxygen gas. The solar thermochemical conversion of CO2 and H2O into syngas is usually carried out at a high temperature of above 1500°C in repeated heating−cooling cycles with the help of durable metal oxide catalysts. Oxygen Transport Membranes (OTMs) are high density ceramic membranes which display mixed conductivity of oxygen ions and electrons and a two-phase mixed metal oxide OTM could thermo-chemically convert CO2 and H2O to syngas in a single step with an H2/CO ratio of 2:1; thus offering an alternative route for syngas production.
    [Show full text]