Knudsen Flow and Chemical Reaction in a Porous Catalyst

Chambre has shown that the diffusion and reaction in a catalyst whose relevant dimensions are much smaller than the molecular mean free path are determined by the Clausing–DeMarcus integral equation for internal free‐molecule flow. A rigorous upper bound on the reaction rate for the irreversible reaction A → B occurring on the internal surfaces of such a catalyst is formulated from a variational inequality due to Kourganoff and DeMarcus. The bounds are evaluated for two pore models, a bed of randomly over‐lapping solid spheres and a right circular cylinder.