Experimental study of the nitrogen oxide emissions characteristics of a bituminous coal with a high fuel nitrogen content under the condition of the air staged combustion

Experimentally studied were the nitrogen oxide emissions and burn-out conditions under the condition of the air staged combustion of two kinds of bituminous coal with a relatively high fuel nitrogen content. It has been found that under the condition of coal combustion with air being not staged, the higher the fuel nitrogen content of the coal, the higher the amount of the nitrogen oxide emissions and under the condition of the air staged combustion, the lower the conversion rate of the fuel nitrogen to NO_x. Under the condition of the air staged combustion, when the residence time in the reduction zone is between 0.8 s and 1.0 s and the chemical equivalent ratio is 0.75, both Datong-originated and Russia-originated bituminous coal can achieve a relatively low amount of nitrogen oxide emissions. In the meantime, under the condition of the air staged combustion, the burn-out degree of Russia-originated bituminous coal is similar to that of Datong-originated bituminous coal, featuring a relatively good burn-out degree.