Transformation of denitrification and nitrogen reduction of cement kiln tail flue gas

NOx produced in cement kiln is mainly thermal NOx and fuel NOx. Thermal NOx is nitrogen in combustion air, which is produced when it is oxidized at high temperature above 1500℃. Nitride contained in fuel NOx is oxidized as fuel and produced during combustion. Both NOx are related to combustion process. The temperature of rotary kiln is above 1500℃, and that of decomposing furnace is below 1000℃. Generally, visible NOx mainly comes from kiln, combining the formation characteristics and main features of NOx. The main method of pre-combustion control is to control the nitrogen content in fuel, but this technology has not been well developed. Combustion process control methods mainly include staged combustion and low oxygen combustion. The main methods of post-combustion control are SCR and SNCR. Generally speaking, both pre-combustion control and post-combustion control require extra equipment, large investment and increased operating cost. The control method of combustion process is from the point of view of optimizing combustion, which only needs to transform the existing equipment without increasing the daily operation cost.