Modeling of Noncatalytic Gas-Solid Reactions the Reaction Zone Thickness

A number of physical and mathematical models have been proposed for noncatalytic solid-gas reactions. In such a system, the reaction takes place in a part of the solid that can vary in large limits. Within this study, calculations with respect to the gaseous reactant, for simple isothermal first order reactions, have been carried out. The size of the specific reaction area is established and correlated with a mathematical model characterizing the chemical transformation that takes place. Depending on the specific thickness of the reaction zone, some well-known noncatalytic gas-solid reaction models such as: the shrinking core model (heterogeneous), the limited reaction zone model (general) and the total reaction zone model (homogeneous), have been re-established.