Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-12, 2016 ISSN: 2454-1362, http://www.onlinejournal.in

Review on Reactive and Recent Applications

Rahul Gupta1, Saumya Shah2 & Shubham Dubey3 1, 2,3Department of Chemical engineering, Indore Institute of Science and Technology, Indore, India

Abstract-Reactive distillation columns can render one or more of the products are removed more of the great advantages in capital investment and operating product will be formed because of Le Chatlier's cost over the conventional reactor/separator/recycle Principle, Removing one or more of the products is systems for some simple reaction operation and one of the principles behind reactive distillation (RD) separation operation. In the case of the separations [14]. of some complicated reacting mixtures including The term is also used for such multiple step reactions, a train of reactive distillation Systems where a catalyst (homogeneous or columns is frequently needed. Although such kind of heterogeneous) is used to accelerate the reaction [12]. systems can present superior performance in Being a relatively new field, research on various comparison with their conventional counterparts, it is aspects such as modeling and simulation, process likely to go further in seeking the potential of process synthesis, column hardware design, non-linear intensification. It is noted that in addition to multiple dynamics and control is in progress. The suitability of condensers and reboilers, outlet and inlet streams, reactive distillation (RD) for a particular reaction and possible recycle streams, each reactive depends on various factors such as volatilities of distillation column involved carries out only one reactants and products along with the feasible reaction operation and separation operation. These reaction and distillation temperature. Hence, the use points remind us of arranging multiple reaction and of reactive distillation (RD) for every reaction may separation operations in a single reactive distillation not be feasible. Exploring the candidate reactions for column and this leads to a reactive distillation reactive distillation ( RD), it is an area that needs column with multiple reaction zones. considerable attention to expand the domain of reactive distillation (RD) processes.

Keywords- Reactive distillation, Application, Reaction, Operation, Biodiesel

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1. Introduction

Reactive Distillation (RD) is a process where the reaction and distillation both the processes taken place in a single column. Separation of the product from the reaction mixture does not need a separate distillation step, which saves energy (for heating) and materials. This Technique was invented in 1921, but the industrial application of reactive distillation (RD) taken place after the 1980s [6 ]. This technique is especially useful for equilibrium-limited reactions such as esterification and reactions. Conversion can be raised far beyond what is expected by the equilibrium Figure 1: The basic elements of a reactive distillation due to the continuous removal of reaction products column [15]. from the reaction zone [3]. Reactive distillation (RD) The high boiling reactant is fed as feed 1 and the low is used with reversible, liquid phase reactions. For boiling reactant as feed 2. Between the two feeds, many reversible reactions the equilibrium point lies there is the reaction zone [15]. far to the left and little product is formed, however, if

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Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-12, 2016 ISSN: 2454-1362, http://www.onlinejournal.in

2. Theory detergents. High purity methyl valerate (VAME) can also be used as a kind of plasticizer. A reactive Reactive distillation (RD) often shows complex distillation (RD) column is used in the production behavior such as steady state multiplicity, process process to overcome equilibrium limitation of the gain sign changes and strong interactions between esterification reaction. Products, methyl valerate process variables, this results in that reactive (VAME) and water are withdrawn from the distillate distillation (RD) processes are often non-linear in of reactive distillation (RD) column and then can be nature. This presents a strong challenge for the separated by two strippers and a decanter. A construction of a working control structure. Even thermally coupled design is then developed to reduce though an increasing number of papers on reactive the remixing effect in the rectifying section of the distillation columns have been published in the past reactive distillation(RD) column. The simulation years, still there is a gap in the market regarding a results show that 30% energy saving can be achieved systematic plant-wide control procedure with focus by using the proposed thermally coupled on optimization [5]. configuration, but only 17% of total annual costs can Reduction of energy and equipment cost is possible be saved due to the use of a compressor.[2] by thermally coupled distillation sequences as they allow interconnecting vapor and liquid flows between • 2.1.2. Reactive distillation (RD) for the two columns to eliminate the reboiler or production of Furfural using solid acid catalyst, condenser or both. Thermally-coupled side-rectifier, In this process reactive distillation (RD) uses solid side stripper, and Petlyuk columns are the three well- acid catalysts for producing furfural from synthetic known configurations. Petlyuk configuration is and real (pre-hydrolysate liquor (PHL) from wood restricted due to bidirectional vapor and liquid flows. chip digestion) feeds containing xylose. The reactive The side-rectifier and side-stripper configurations distillation (RD) process provides a unique advantage tend to be the most efficient ones [8]. of immediate furfural separation from the reaction Reactive distillation (RD) column with the two zone as it is formed, thus minimizing the formation of reaction zones is also in practice. In terms of undesired by-products (e.g., oligomers of thermodynamic characteristics of reaction operation furfural/humins) from subsequent furfural and separation operation involved, a reactive condensation reactions. An in situ catalyst distillation (RD) column with two reaction zones is regeneration method was demonstrated successfully proposed for the production of cyclohexanol by and resulted in achieving extended catalyst lifetime indirect hydration of cyclohexene. The arrangement and furfural yield, similar to that obtained with of two separate reaction zones not only allows the synthetic xylose feeds.[9] careful coordination of the two reaction operations involved, but also provides additional degrees of freedom for the reinforcement of internal mass integration and/or internal energy integration between the reaction operations and the separation operation involved [16]. Through deep comparison between the reactive distillation (RD) column with two reaction zones and the coupled reactive distillation (RD) columns, it is demonstrated that the former could lead to reduced total annual cost in comparison with the latter. The reactive distillation (RD) column with two reaction zones should therefore be considered as a competitive alternative to the coupled reactive distillation (RD) Figure 2[9] columns for the production of cyclohexanol by indirect hydration of cyclohexene [16]. 2.1.3. Reactive distillation (RD) process for the production of fluorinated alkenes, The preparation A. 2.1. Reactive distillation (RD) has many of suitable chlorofluorocarbon and hydro applications which are as follows – chlorofluorocarbon materials or chlorofluorocarbon and hydro chlorofluorocarbon alkene and alkyne • 2.1.1. Reactive distillation (RD) process intermediates which serve as useful feedstock for for Methyl Valerate, Methyl valerate (VAME), also fluorination and reduction to cis-1,1,1,4,4,4- known as methyl pentanoate, is a methyl of hexafluoro-2-butene. Also, a continuous process for pentanoic acid (valeric acid). Methyl valerate the production of cis-1,1,1,4,4,4-hexafluoro-2-butene (VAME) is usually used as a fragrance in the from the alkene and alkyne intermediates.[1] production of beauty care, soap, and laundry

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Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-12, 2016 ISSN: 2454-1362, http://www.onlinejournal.in

2.1.4. Reactive Distillation (RD) of Biodiesel, With • 2.3.2. The introduction of an in situ global increased energy demands, the continued separation process in the reaction zone or vice versa depletion of fossil fuels and problems associated with leads to complex interactions between vapor–liquid global warming and emissions, it is necessary to equilibrium, mass transfer rates, diffusion and focus research on development of renewable fuel chemical kinetics, which poses a great challenge for alternatives. Biodiesel is a carbon-neutral alternative design and synthesis of these systems. which can be used in most automotive engines • 2.3.3. Side reactors, where separate columns without need for modification. Reactive distillation feeds a reactor and vice versa, are better for some (RD) is an integrated reactive and separation unit reactions, if the optimal conditions of distillation and which offers several potential benefits; less waste reaction differ too much. processing, higher yield of product, better separation and large savings on both OPEX and CAPEX [5]. H. 2.4 PUBLICATIONS OF PAPERS AND RESEARCH WORKS- 2.1.5. Biodiesel production using thermally Last few years have seen a dramatic rise in the coupled reactive distillation (RD), Production of number of applications of reactive distillation (RD). ethyl dodecanoate (biodiesel) using lauric acid and This useful technology is now being applied for any with a solid acid catalyst of sulfated scale of operation- from manufacture of fine zirconia is studied by using two distillation chemicals to that of bulk chemicals. sequences. In the first sequence, the methanol Reactive distillation (RD) has been successfully used recovery column follows the reactive distillation and investigated in the past for several reactions such (RD) column. In the second sequence, the reactive as etherification, esterification, hydrogenation, distillation (RD) and methanol recovery columns are hydrodesulphurization and polymerization. Various thermally coupled. Thermally coupled distillation reviews have been published on this aspect [4-10-12- sequences may consume less energy by allowing 7]. However, even after the recent review by Sharma interconnecting vapor and liquid streams between the and Mahajani (2003) that was presented in the first two columns to eliminate reboiler or condenser or international workshop on reactive distillation (RD) both. [8]. held at Magdeburg, Germany in 2001, an increasing number of articles have appeared in the last couple of 2.1.6. Transesterification process by combination years. An updated version of the recently published of reactive distillation (RD) and pervaporation, statistics [, shows that there are around 180 papers the development of a reactive distillation process for and 100 patents published in the last two years on the production of n-butyl acetate by reactive distillation (RD) alone. This clearly reveals transesterification of methyl acetate with n-butanol the increasing interest in this area. Apart from the [13]. theoretical aspects of reactive distillation (RD), we see the research being performed mainly in two B. 2.2. PROS OF REACTIVE different directions, firstly, in improving the DISTILLATION (RD)- performance of reactive distillation (RD) for the C. existing applications and secondly, in exploring new D. Some of the benefits of reactive distillation applications. Hence, considering the growing rate of (RD) are – publications, we felt it necessary to review this • 2.2.1. Increased speed. voluminous information shortly after the gap of about • 2.2.2. Lower costs – reduced equipment use, 2-3 years. The present article is intended to serve as a energy use and handling. supplement to the review by Sharma and Mahajani • 2.2.3. Less waste and fewer byproducts. (2003) which we feel the reader to go through as • 2.2.4. Improved product quality- reducing well, in order to get an idea of the entire spectrum of opportunity for degradation because of less heat. reactions that comes under the umbrella of reactive distillation. E. 2.3 CONS OF REACTIVE DISTILLATION (RD)- 3. Conclusion F. G. As everything has pros and cons of its own , Reactive distillation (RD) has major impact on reactive distillation (RD) also have its own economy of industries, and also with the developing complications that are as follows : world new technologies replacing the conventional • 2.3.1. The conditions in the reactive column one, in this sense reactive distillation (RD) is the are suboptimal both as a chemical reactor and as perfect example. Time is money and and reduction in a distillation column, since the reactive column manufacturing time plays a major role for any of the combines these. developing industries. New implementations in the

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Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-12, 2016 ISSN: 2454-1362, http://www.onlinejournal.in design of reactive distillation (RD) column leading to M. (Eds.), Academic Press, London, UK, (2001), the great reduction in the capital cost and energy cost. 4075-4. One of the important aspects of reactive distillation [13] Sven Steinigeweg, jurgen gmehling, (RD) is that it has low impact on environmental “Transesterification Processes By Combination Of Reactive Distillation And Preevaporation”. conditions and also proving to be the safe and reliable [14] Timothy Mashue and H. Scott Fogler. process. [15] Trevor Letcher, book on: “Chemical Reactive distillation (RD) has set up its application as Thermodynamics for Industry”, The Royal the unit operation in the process technology. Society of Chemistry: Letchworth, U.K., 2004. In nutshell we can say that reactive distillation (RD) ISBN 0-85404-591-0. is becoming the front-runner in the field of process [16] Xinhui Yao, Kejin Huang, Kun Wang, Ningning intensification. Wei and Mingyao Li , “A Reactive Distillation Column with Two Reaction Zones for the Cyclohexanol Production from Cyclohexene” 4. References 2014 Spring Meeting & 10th Global Congress on Process Safety (ISBN: 978-0-8169-1083-0). [1] Andrew Joseph Poss, David Nalewajek, Michael Van Der Puy, Haridasan K. Nair, “Process for the production of fluorinated alkenes”, Honeywell International Inc., US 13/110,992. [2] Cheng-Liang Chen†, Yao-Hsien Chung†, and Hao-Yeh Lee, “Design and Control of Reactive Distillation Process for the Production of Methyl Valerate”, Ind. Eng. Chem. Res., 2016, 55 (5), pp. 1347–1360. [3] Chokchai Mueanmas, Kulchanat Prasertsit and Chakrit Tongurai, “Feasibility Study of Reactive Distillation Column for Transesterification of Palm Oils”, International Journal of Chemical Engineering and Applications, Vol. 1, No. 1, June 2010, ISSN: 2010-0221. [4] Doherty, M.F. and Buzad G, “Reactive distillation by design”, Chem. Eng. Res. and Design,Transactions of the Institution of Chem. Engineers, Part A, Vol. 70, 448-458 (1992). [5] Emilie Øritsland Houge, “Reactive Distillation of Biodiesel: Modeling and Optimal Operation”, Chemical Engineering and Biotechnology (June 2013). [6] en.wikipedia.org/wiki/Reactive distillation. [7] M .M. Sharma, S.M. Mahajani, “Reactive Distillation: Status and Future Directions”, Wiley- VCH Verlag GmbH & Co. [8] Nghi Nguyen and Yaşar Demirel, Using Thermally Coupled Reactive Distillation Columns in Biodiesel Production, The International Journal (2011) 36: 4,838-4,847. [9] Pranit S. Metkar, Eric J. Till, David R. Corbin, Carmo J. Pereira, Keith W. Hutchenson and Sourav K. Sengupta, “Reactive distillation process for the production of furfural using solid acid catalysts”, Green Chem., 2015,17, 1453-1466. [10] R. Taylor, R. Krishna, Review: “Modeling reactive distillation”, Chemical Engineering Science 55 (2000) 5183}5229. [11] Robert S. Huss, Fengrong Chen, Michael F. Malone, Michael F. Doherty, “Reactive distillation for methyl acetate production”, Computers and Chemical Engineering 27 (2003) 1855_/1866. [12] S. M. Mahajani, S. P. Chopade, “Reactive Distillation: Processes of Commercial Importance”, in Encyclopedia of Separation Science, by Edlard T. R., Poole C. A. and Cooke

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