JUSTIFICATION OF THE INTERNAL ISOTHERMAL MODEL FOR GAS-SOLID CATALYTIC REACTIONS

The commonly employed internal isothermal model for gas‐solid catalytic reactions, wherein the pellet is assumed internally isothermal but with internal concentration gradient, is justified by analyzing the full non‐isothermal diffusion‐reaction equations as an appropriate perturbation problem (β small, and Bih/β finite). The internal isothermal model is shown to be the zeroth order solution of the perturbation problem. Analytic expressions for the first order corrections are given for a first order reaction. Copyright © 1979 American Institute of Chemical Engineers