PRESSURE-DROP MEMBRANE REACTOR EQUILIBRIUM-ANALYSIS

An analysis is performed for predicting conversion in membrane reactors with pores both catalytically active and so narrow that intrapore transport is in the Knudsen regime. The analysis is illustrated for A = B + C (e.g., dehydrogenation) stoichiometry, and for the limiting case of very fast, reversible reactions -i. i.e., large Thiele modulus. Thus, local concentrations are calculated from an equilibrium relationship. 'Supra-equilibrium' conversion is predicted. However, a distinction is drawn between effects attributable to permselective properties of the membrane and those simply required by le Chatelier's principle. This analysis of conversion in a catalytic membrane reactor allows the influence of intrinsic membrane properties (such as diffusivity differences) to be separated from those of extrinsic factors (such as differences in trans-membrane pressure and dilution of products in a sweep gas which may be flowing on the permeate side of the membrane). Furthermore, external mass transfer resistance, heretofore generally neglected, is examined from a multicomponent diffusion approach.