The catalysts used in the flue gas denitrification equipment of YIRAN environmental protection heat treatment furnace are active components, which are made into three types: honeycomb type, plate type or ripple type. The SCR catalysts used in flue gas denitrification can be divided into three types: high temperature catalyst (345 ℃ ~ 590 ℃), medium temperature catalyst (260 ℃ ~ 380 ℃) and low temperature catalyst (80 ℃ ~ 300 ℃). If the reaction temperature is too low, the activity of the catalyst will be reduced, resulting in a decline in the efficiency of denitrification, and if the catalyst continues to operate at low temperature, the catalyst will be damaged; If the temperature of heat treatment furnace flue gas denitrification reaction is too high, NH3 is easy to be oxidized, and the amount of NOx is increased, which will cause the phase transformation of catalyst materials and the degradation of catalyst activity. High temperature is adopted in most SCR systems at home and abroad, and the reaction temperature ranges from 315C to 400C. Heat treatment furnace denitrification advantages: the method of denitrification efficiency is high, the price is relatively low.