A rate equation for gas-solid reactions accounting for the effect of solid structure and its application

Abstract

An integrated form of the rate equation for gas-solid reactions is proposed, taking into account the effect of solid structure on the reactivity of the solid. The rate equation is verified by the oxidation of iron sulfide particles, which follows the volume reaction model, with solid structure being varied due to different extent of sintering. The rate constant based on unit particle volume takes distinct value depending on the structure of the solid phase, yielding identical apparent activation energy. The surface rate constant is then evaluated on the basis of the effective surface area for the reaction being separated from the solid structure and is correlated in an Arrhenius equation. The proposed rate equation is approved to embrace a variety of kinetic equations used not only in the volume reaction model but in the grain model, in shrinking core kinetics, and in the gasification of a porous particle. © 1981, The Society of Chemical Engineers, Japan. All rights reserved.