Abstract: Taking the modification of ammonia injection grid(AIG) in a coal-fired power plant for instance, the effects of the modification are evaluated through numerical simulation and calculation. The results demonstrate that the two-way regulating function is beneficial to the even distribution of ammonia and it improves the adaptability to the uneven flue gas velocities. Moreover, the relative standard deviation of the outlet NOx distribution declines from 40% to lower than 15%. The modification improves SCR ammonia spraying effectiveness, increases the catalyst life span, eliminates the local high concentration of ammonia slip at the reactor outlet, reduces the risk of downstream ABS corrosion in the air pre-heater, and it therefore helps the coal-fired power plant achieve super-low NOx emissions.

Key words: coal-fired power plant, flue gas denitrification, selective catalytic reduction(SCR), ammonia injection system, modification, numerical simulation