The utilization hours of thermal power units continue to decline

and peak shavings become more frequent. Under this background

the existing ammonia injection mixing technology can no longer meet the new normal needs of coal-fired power plants

and ultra-low emissions put forward higher requirements for uniformity of the NH3/NO_x molar ratio distribution at the SCR reactor inlet. The grid-type ammonia injection grid(AIG) and static mixer are optimized through CFD numerical simulation and physical model test. The design method and an anti-blocking nozzle are proposed to ensure the uniformity of ammonia distribution

adjustment flexibility

and antiblocking performance of the ammonia injection grid. Moreover

a triangular large-scale flue gas self-mixing device is developed to improve the uniformity of the NO_x concentration field at inlet of the SCR reactor and enhance the load adaptability of the SCR denitrification device from the root. The relative standard deviation of NO_x distribution at the SCR outlet of a 600 MW unit under high

medium and low loads reached 8%～19% by using this technology

and the ammonia escape at full load decreased by 51%.