Experimental study of nitrogen oxide emissions in a circulating fluidized bed

Abstract

The experimental study was carried out on the emission characteristics of nitrogen oxide in a 0.3MW circulating fluidized bed as well as analysis of the formation and destruction mechanism of nitrogen oxide. Several variables associated with the combustion system were investigated in the experiment, which include bed temperature, excess air, primary-to-secondary air ratio, and coal species. It is found that the NOx emissions decrease along the height of the furnace, while the N2O emissions increase continuously. More NOx emissions and less N2O emissions are generated as the bed temperature increases. It is also illustrated that an increase of air stoichiometry leads to a significant NOx increase and an obvious N2O increase. And air staging is proved to be an effective way to control the nitrogen oxide emissions in the fluid bed. Besides, it is also shown in the experiment that the concentration of NOx and N2O is higher during the combustion of anthracite than that during the combustion of bituminous.