Physicomathematical modeling of ignition of a heterogeneous mixture of methane, hydrogen, and coal microparticles

A physicomathematical model is developed for ignition and combustion of a methane–air mixture containing coal microparticles. The model takes into account the detailed kinetics of oxidation of the gaseous methane–hydrogen–air mixture and the processes of thermal destruction of coal particles with release of volatiles (methane and hydrogen) to the gas phase, ignition and combustion of these volatiles in the gas phase, and heterogeneous reaction of carbon oxidation. It is demonstrated that addition of coal particles to the methane–air mixture in the temperature interval from 900 to 1450 K reduces the ignition delay time. Moreover, addition of coal particles to the methane–air mixture leads to shifting of the ignition limit of the gas mixture toward lower temperatures. The calculated delay time of coal ignition in the air–coal mixture and the predicted delay times of methane and coal ignition in the methane–air–coal mixture are found to be in reasonable agreement with experimental data obtained in a rapid compression machine.