Zeolite membrane reactors membranes

Table 10.2 Performance of several zeolite membrane reactors in the xylene isomerization reaction. 

Modeling on the reactor level, which is needed in designing the zeolite membrane reactor, could receive some more attention, since the number of studies in this particular field are few [56,106]. 

Lin, J.Y.S., Zeolite Membrane Reactor for Water-Gas-Shift Reaction for Hydrogen Production, Proceedings of2007 U.S. DOE Hydrogen Annual Merit Review Meeting, Arlington, VA, May 2007. 

S., Fiaty, K., and Dalmon, J.-A. (2000) Experimental smdy and numerical simulation of hydrogen/isobutane permeation and separation using MFI-zeolite membrane reactor. Catal. Today, 56 (1-3), 253-264. 

One of the main challenges for zeolite membrane reactors is that optimal reactor operation requires that the membrane flux be in balance with the reaction rate.. Whether acting in an inert or catalytic capacity, the extractive ability of the membrane needs to keep up with the production of the species being removed in order to fully participate in improving the reaction yield [44]. 

Improved selectivity in the liquid-phase oligomerization of i-butene by extraction of a primary product (i-octene C8) in a zeolite membrane reactor (acid resin catalyst bed located on the membrane tube side) with respect to a conventional fixed-bed reactor has been reported [35]. The MFI (silicalite) membrane selectively removes the C8 product from the reaction environment, thus reducing the formation of other unwanted byproducts. Another interesting example is the isobutane (iC4) dehydrogenation carried out in an extractor-type zeolite CMR (including a Pt-based fixed-bed catalyst) in which the removal of the hydrogen allows the equilibrium limitations to be overcome [36],... 

Zeolite-Membrane Reactors for Conversion Enhancement by Product Removal.298... 

Zeolite-Membrane Reactors as Reactant Distributors for Selectivity Enhancement.301... 

Zeolite-Membrane Reactors for Selectivity Enhancement by Control of Reactant Traffic ... 

Catalytic Zeolite-Membrane Reactors in the Line Chemicals Industry.305... 

This chapter gives an overview of the synthesis procedures and appUcations of zeoUte membranes (gas separation, pervaporation, zeolite-membrane reactors), as well as new emerging appUcations in the micro- and nanotechnology field. Related areas such as new zeoUte and zeoUte-related materials for membranes, alternative supports, and scale-up issues are also discussed. 

Nevertheless, the development of zeolite-membrane reactors still requires improvements in the fluxes and separation factors attained to date, an objective to which many efforts have been devoted in recent years with the aim of materializing an industrial application of zeolite-membrane reactors. Several reviews have been published in the last 5 years dealing completely or partially with zeolite membranes [2,3,5,161,162,165-167]. Particularly, noteworthy have been the advances regarding the use of supports of different natures and characteristics (see Section 10.6.4), the control of the orientation and thickness of zeolite layers (see Section 10.2.1.2), and the preparation of new zeolite materials such as membranes (see Section 10.3). In spite of these advances, before zeolite-membrane reactors are used in industry (see Section 10.6.5), signihcant progress must be achieved in more prosaic issues such as scale-up and control of the synthesis process to increase membrane reproducibility. 

It has been considered traditional applications of zeolite-membrane reactors those based on reactor concepts already demonstrated using mesoporous or dense membranes. These include conversion enhancement by equilibrium displacement or by the removal of inhibitors, and selectivity enhancement by reactant distribution. For such cases, the zeolite membrane is usually catalytically inert and is coupled with a conventional fixed bed of catalyst placed on one of the membrane sides. 

Relatively, few examples have been found in literature about catalytic zeolite-membrane reactors, and most of them are related with the fine chemicals industry as is shown in the following sections. 

Alternative Supports and Configurations for Zeolite-Membrane Reactors... 

While, in general, the investigations discussed in this section do not belong to the field of zeolite-membrane reactors, they are mentioned here because they provide interesting clues and ideas for further development of existing systems. 

New Applications of Zeolite-Membrane Reactors Microchemical Systems... 

Coronas J and Santamaria . State-of-the-art in zeolite membrane reactors. Topics Catal 2004 29(l-2) 29-44. 

Jeong BH, Sotowa KI, and Kusakabe K. Catalytic dehydrogenation of cyclohexane in an FAU-type zeolite membrane reactor. J Membr 5d2003 224 151-158. 

Liu BS and Au CT. A La2Ni04-zeolite membrane reactors for the CO2 reforming of methane to syngas. Catal Lett 2001 77(l-3) 67-74. 

Salomon MA, Coronas J, Menendez M, and Santamarfa J. Synthesis of MTBE in zeolite membrane reactors. Appl Catal A Gen 2000 200 201-210. 

Barbieri G, Marigliano G, Golemme G, and Drioli E. Simulation of CO2 hydrogenation with CH3OH removal in a zeolite membrane reactor. Chem Eng J 2002 85 53-59. 

Gallucci F, Paturzo L, and Basile A. An experimental study of CO2 hydrogenation into methanol involving a zeolite membrane reactor. Chem Eng Proc 2004 43 1029-1036. 

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