Catalytic non-permselective membrane reactor

CATALYTIC NON-PERMSELECTIVE MEMBRANE REACTORS WITH AN OPPOSING REACTANTS GEOMETRY (CNMR/ORG)... 

Concept of a Catalytic Non-Permselective Membrane Reactor with an Opposing Reactants Geometry... 

Figure 5.12. Catalytic non-permselective membrane reactor for the reaction A + B -> 2C.

Packed Bed Catalytic Membrane Reactor Fluidized Bed Membrane Reactor Fluidized Bed Catalytic Membrane Reactor Catalytic Non-permselective Membrane Reactor Supported Liquid-phase Catalytic Membrane Reactor-Separator... 

Figure 5 Catalytic non-permselective membrane reactor with separated feed, showing transmembrane concentration profiles of the species and the direction of permeation...

Sloot, H. 1991. A non-permselective membrane reactor for catalytic gas phase reactions. Thesis, University of Twcntc, Enschede. 

There are, however, some studies demonstrating another concept of using porous membranes. In this concept, the permselective property of a membrane is immaterial and not utilized. Instead, the well sU uctured porous maU ix of the membrane serves to provide a well controlled reaction zone. Specifically, two reactants are fed separately to the opposing sides of a catalytic membrane. For those reactions the rate of which is faster than the diffusion rate of the reactants in the membrane, the reaction can take place inside the caialytically active membrane. This type of membrane reactor, where the membranes are catalytic but not selective, are called catalytic non-pcrmselective membrane reactors (CNMR). 

Another type of catalytic and yet non-permselective membrane reactors uses one side of the membrane as the phase boundary between gas and liquid reaction streams. An example is the reaction between a gaseous reactant (A) flowing in the tube core while a liquid containing the solution of the other reactant (B) in a suitable solvent flowing in the annular region (Figure 10.17) ... 

Catalytic Non-permselective Membrane Multiphase Reactor (CNMMR) Model - Laminar Flow Liquid Stream... 

As a building block for simulating more complex and practical membrane reactors, various membrane reactor models with simple geometries available from the literature have been reviewed. Four types of shell-and-tube membrane reactor models are presented packed-bed catalytic membrane reactors (a special case of which is catalytic membrane reactors), fluidized-bed catalytic membrane reactors, catalytic non-permselecdve membrane reactors with an opposing reactants geometry and catalytic non-permselective membrane multiphase reactors. Both dense and porous inorganic membranes have been considered. 

Veldsink J.W., A Catalytically Active, Non-permselective Membrane Reactor for Kinetically Fast, Strongly Exothermic Heterogeneous Reactions. Ph.D. dissertation, Twentc University of Technology, Enschede, the Netherlands (1993). 

Sloot, H., Versteeg, G., Smolders, C., et al. (1991). A Non-Permselective Membrane Reactor for the Selective Catalytic Reduction of NOx with Ammonia, in Proc. 2nd Int. Conf. on Inorganic Membranes, Montpellier (France), Trans. Tech. Publ., Zuerich (Switzerland). 

There are a number of membrane reactor systems, which have been studied experimentally, that fall outside the scope of this model, however, including reactors utilizing macroporous non-permselective membranes, multi-layer asymmetric membranes, etc. Models that have been developed to describe such reactors will be discussed throughout this chapter. In the membrane bioreactor literature, in particular, but also for some of the proposed large-scale catalytic membrane reactor systems (e.g., synthesis gas production) the experimental systems utilized are often very complex, in terms of their configuration, geometry, and, of course, reaction and transport characteristics. Completely effective models to describe these reactors have yet to be published, and the development of such models still remains an important technical challenge. 

As discussed in Chapter 2, in a number of membrane reactor applications the membrane is non-permselective, and it simply acts as a contactor device (when it is catalytic), or simply as a means to distribute one of the reactants in a more uniform manner (when it is inert). In modeling such reactors one must take into consideration, in addition to Knudsen diffusion, the presence of molecular diffusion and convective transport. The Dusty Gas Model... 

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