In order to alleviate the problems of uneven distribution of NO_x mass concentration and large local ammonia escape at outlet of the denitrification reactor in selective catalytic reduction(SCR) denitrification system of coal-fired power plants

this article introduces the ammonia injection optimization adjustment process of SCR denitrification system of coal-fired power plants in detail

based on the practical example of a swirl combustion boiler. It points out three major steps of the ammonia injection optimization adjustment: mapping diagnosis

optimization adjustment

and effect verification. After adjusting

at 495 MW load

the mass concentration of NO_x at outlet of the chimney was controlled at about 25 mg/m~3

the unevenness of distribution of the NO_x mass concentration at outlet of the denitrification reactor decreased from 57.6% and 90.2% to 33.8% and 35.6%

respectively

the volume ratio of ammonia escape decreased from 1.93 μL/L and 2.09 μL/L to 1.31 μL/L and 1.44 μL/L

respectively

and the deviation of online instrument value of NO_x mass concentration between the reactor outlet and chimney outlet decreased to less than 10 mg/m~3

which demonstrated that the adjustment effect is obvious.