MODELING OF SPONTANEOUS COMBUSTION OF COAL WITH MOISTURE-CONTENT INCLUDED

A mathematical model for spontaneous combustion of coal has been devel oped that takes into consideration the moisture content of coal. The o ne-dimensional non-steady-state model consists of conservation equatio ns for oxygen, water vapour, inherent moisture of the coal, and energy for both gaseous and solid phases. A first-order Arrhenius reaction r ate for oxidation under pore diffusion and chemically controlled react ion regimes is considered. The rate of evaporation or condensation is also considered as a function of particle size, isothermal temperature of coal particles, energy of water-coal bonding and water content of coal and gas streams. The equations of the model have been solved nume rically by finite-difference technique, and the influences of gas velo city, particle size and inherent moisture content on the process of sp ontaneous heating have been examined parametrically.