A new solution technique of moving boundary problems for gas-solid reactions; Application to half-order volume reaction model

Mathematical modelling of a non-catalytic gas-solid reaction in a porous pellet, where both diffusion and chemical reaction are important, is represented by a pair of coupled partial differential equations. When the kinetics are half-order with respect to solid concentration, no analytical solution exists. Therefore numerical solutions or approximate methods have been used. In this work a new incremental analytical method of solution has been developed. The results of this method in comparison with the existing numerical and approximate solutions show high accuracy and good fitting. The method is very simple to handle with small calculators and also gives some analytical expressions for gas and solid concentrations.