Review of applicability of unreacted core model based on Ishida–Wen model

Abstract

The unreacted core model has been used for analysis of the gaseous reduction rate of iron oxide. However, the rate parameters in this model are known to be affected by many factors, such as reactivity, diffusivities in the reactant zone and through the product layer and size and shape of the solid particle, so the applicability of this model has been criticised. In the present study, the applicability of the unreacted core model is reviewed based on the Ishida–Wen model, which is known to be strict and versatile. According to the review, the unreacted core model has good applicability under conditions of higher reactivity and/or much larger diffusivity through the product layer than in the reactant zone, and poor applicability under conditions of lower reactivity and/or the same diffusivity through the product layer as in the reactant zone.