Initiation of combustion of coal particles coated with a water film in a high-temperature air flow

Results of an experimental study of ignition of a coal–water fuel in a high-temperature air flow are presented. The fuel is obtained on the basis of the mark D coal or filter cake of the Severnaya dressing plant. Based on the experimental results, physical and mathematical models of the processes of thermal preparation and ignition of coal–water fuel particles are formulated, which take into account the joint proceeding of the most relevant physical and chemical transformations (which exert an essential effect on the ignition condition) and the processes of heat and mass transfer during the induction period. A comparison of the basic ignition characteristics (ignition delay time and limiting values of the gas medium temperature), which are obtained experimentally and theoretically (based on results of numerical simulations), leads to a conclusion that the water film affects the dynamics of the ignition process.