Identification of significant factors in reburning with coal volatiles.

In laboratory-scale flow reactor studies, fuel staging using coal volatiles as a reburning fuel has given superior NOx reduction performance compared to reburning using natural gas. This superior performance of coal volatiles may be caused by an increased yield of hydrocarbon radicals and free nitrogen species in the reburning zone. In this study, kinetic models were used to predict the composition of coal volatiles used in reburning. The reburning process was then examined using a set of designed experiments to examine the components of the coal volatiles and their effects on NOx reduction. Within the concentration ranges studied, reburning temperature and air concentration were shown to control NOx reduction, and reburn gas component concentrations had only minor effects.