A time dependent numerical model was developed to predict the generation of unburned hydrocarbons and the emissions of NOx, SO {sub 2}, CO and CO {sub 2} to simulate coal combustion on moving and fixed grates. It was shown that tempering improved combustion efficiency, aided ignition, and propagation of the ignition plane down to the grate level. A mathematical model was used to predict the effect of tempering. 4 refs., 2 figs.
