Abstract: In order to lower the high DeNO_x costs of the existing coal-fired power generating units, the effects of various factors on the average SCR DeNO_x costs are studied, including the unit type, unit capacity, denitrification efficiency, reductant type, inlet NO_x concentration and the power consumption rate of denitrification, etc. Through the analysis on the composition of the SCR DeNO_x cost, it is concluded that the operating costs and the financial costs are the major parts of the DeNO_x cost. Therefore, optimizations on reductant consumption, soot blowing system and catalyst are proposed to reduce the DeNO_x costs, so as to lay solid foundation for the economic and stable operation of the flue gas SCR system.

Key words: thermal power plant, flue gas denitrification, SCR, DeNOx cost