Calculation of the gasification of cokes of high-ash coals on the basis of the model of randomly porous media

A mathematical model is constructed to describe the dynamics of the pore structure of cokes of high-ash coals with allowance for the fact that the different parts of the internal volume of the structure are not equally accessible to the gaseous reactant. The model accounts for the increase in the area of the pore structure due to the removal of organic material, coalescence of pores, and opening of the interior volumes of the sample in the course of conversion. In the examination of heat- and mass-transfer processes inside the particles, attention is given to the thermal effect of the reaction along with diffusion resistance in the mineral component and the layer of reaction products – which decreases the cross section of the transport pores. The results of the calculations are compared with experimental data on the gasification of culm in gaseous carbon dioxide.