NETWORK MODEL INVESTIGATION OF GAS-TRANSPORT IN BIDISPERSE POROUS ADSORBENTS

A capillary network model consisting of a micropore network permeated by one of macropores of randomly varying size has been constructed. Although simplified (to keep computer space and time requirements low) in relation to a real bidisperse porous adsorbent or catalyst, it embodies the salient pore structural features likely to determine the gas-transport behavior of such porous solids. Suitable model calculations of Knudsen gas-phase and surface diffusion enabled us to (i) validate useful approximate methods for the more economical evaluation of network permeability and (ii) demonstrate certain important characteristic effects of nonrandom bidisperse pore structure on transport behavior and their practical consequences, especially in connection with the experimental determination of surface diffusion coefficients.