Production of nitrogen oxide during char oxidation at pulverized coal combustion conditions

More stringent regulations for NOx control in pulverized coal combustors have made the scientific community focus on sources of emissions that were traditionally considered less relevant to the overall NOx production. The oxidation to NO of the nitrogen that is organically bound to the char is one of them. In this study, an experimental evaluation of the influence of the reduction of NO by char was carried out. The experiments with three different carbonaceous materials were conducted at temperatures close to that of pulverized combustion conditions (1700 K) in a laminar drop tube reactor and under inert and oxidizing atmospheres. The results obtained show that the process of NO reduction on the char plays an important role on the total amount of char-N converted to NOx. This NO destruction pathway becomes less important at low NO background concentration and doesn't seem to strongly dependant on the char nature.