The Effect of the Flow Nonuniformity on the Chemical Process in a Catalyst Grain in the Presence of Pore-Diffusion Resistance

Abstract

A catalyst grain in a fixed-bed reactor is surrounded by an non-uniform flow because the reactant concentration changes as the reaction mixture moves through the bed. A problem was considered in which a spherical grain is in an non-uniform flow with a linear dependence of the reactant concentration on the longitudinal coordinate of the reactor in the presence of pore-diffusion resistance in the catalyst grain. For a first-order reaction, an analytical solution for the reactant concentration distribution within the grain was obtained. It was shown that, in comparison with a grain in a uniform flow, the reactant concentration increases in the frontal hemisphere of the grain and decreases in its rear hemisphere, and the grain performance remains unchanged because the increase in the reaction rate in the frontal hemisphere is compensated by its decrease in the rear hemisphere.