Effect of Flue Gas Recirculation on Nitrogen Oxide Emission of Coal-Fired Unit Boiler

Abstract

Taking the flue gas recirculation system of 220MW coal-fired unit as the test object, effects of the operation mode of the flue gas recirculation system on the operating characteristics of the boiler under different working conditions was studied.The results show: the operation of flue gas recirculation system will suppress the amount of NOx generated in the furnace, and the best way to restrain the formation of NOx is to send the recycled flue gas into the furnace through primary and secondary air simultaneously. The flue gas recirculation system can effectively improve the inlet flue gas temperature of SCR, especially when the secondary flue gas recirculation system is put into operation, and the effect of increasing the inlet flue gas temperature of SCR is obviously better than that of the other two operation modes. The operation of flue gas recirculation system can effectively save net coal consumption.