Modeling of non-catalytic gas-solid reactions- Multicomponent nonequimolar counterdiffusion of gaseous phase

The mathematical modeling of non-catalytic gas-solid reactions was carried out based on the grain model in terms of nonequimolar counterdiffusion of gaseous phase in the solid matrix. By justifying the model parameters, the model can be used for the reactions involving volume change between gaseous products and gaseous reactants. The model was used to represent the reduction of chromium oxide with methane in the synthesis of chromium carbide. By justifying the diffusion coefficient of reactant methane through the product layer around the grains, the simulation results showed a good fit to experimental data. A MATLAB m-file, developed to simulate the gas-solid reactions in unsteady state condition for the gas phase mass balance, different reaction orders and considering mass transfer resistances in gas phase outside the solid and through the product layer around the grains. Transport equations were solved numerically by using finite volume technique in implicit form. The model also can be used for studying sensitivity analysis for such reactions.

Keywords:

gas-solid reactions , non-catalytic , nonequimolar , Chromium oxide , Methane