Microporous inorganic membrane reactors

A. Julbe, C. Guizard, A. Larbot, L. Cot and A.G. Fendler, The sol-gel approach to prepare candidate microporous inorganic membranes for membranes reactors. /. Membr. Sci., 77 (1993) 137. 

In some cases, the membrane material is inherently catalytic and the membrane serves as both catalyst and separator, controlling the two important functions of the reactor simultaneously as shown in Figure 1.12(d). A number of meso- and microporous inorganic membrane materials have catalytic properties, such as titania and zeolites with acid sites. As an example, mesoporous Ti02... 

In the present concept of styrene dehydrogenation implementation of inorganic membranes is not feasible. Application of Knudsen diffusion membranes with a low permselectivity to hydrogen leads to a considerable permeation of ethylbenzene and thus, to lower yields. Microporous and palladium membranes give better results, but worse than a conventional case, because the conversion is limited by reaction kinetics. The ratio of permeation rate to reaction rate is very important in selecting membranes in a membrane reactor process in which equilibrium shift is foreseen. 

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