After the popularization of ultralow emission standards for denitration systems in domestic thermal power plants, inaccurate ammonia injection of traditional SCR denitration systems has resulted in excessive NOx emissions, high ammonia escape rate,blockage of air preheaters and so on. Taking No.7 unit of a power plant in Jiangsu as an example, ammonia injection retrofit for the unit was executed sector by sector, and multipoint measurement system for NOx mass concentration and intelligent ammonia injection control logic were added. A big data prediction and analysis station for NOx was established, which can predict the NOx mass concentration more accurately. After the retrofit, the ammonia consumption of the unit is reduced by 8%~10%, NOx distribution at the outlet is uniform, the ammonia escape rate is reduced, the air preheater blockage problem is solved.The ultralow emission of the SCR denitration system is realized.
