The uneven flow field distribution and large ammonia escape value in selective catalytic reduction(SCR) system of a 1 000 MW unit is numerically investigated by ANSYS Fluent software. By analyzing the flow field

concentration field

ammonia escape and denitrification efficiency of the original model

a triangular area spoiler arrangement scheme for the flow field distribution

ammonia inlet angle adjustment and balanced ammonia injection strategy for the reactant concentration field distribution are proposed respectively. The results show that

the addition of five parallel spoilers at the top of the triangular flue area can reduce the excessive velocity of flue gas at the wall

and the relative standard deviation of the catalyst inlet velocity decreases from 16.31% to 8.10%

which effectively improves the uniformity of the flow field distribution of the system. After the ammonia inlet angle optimization combined with the balanced ammonia injection strategy

the relative standard deviation of the ammonia at the catalyst inlet decreases to 20.62%

the average ammonia escape at the reactor outlet reduces from 0.120 03×10~(–3) mol/m~3 to 0.058 23×10~(–3) mol/m~3

which decreases the effect of ammonia escape on the subsequent system.