Simulation on the Influence of a 660 MW Unit Load-up Processes on Denitrification and Particle Removal

The coal-fired power plants operate frequently under off-design condition because of the load fluctuations in power grids caused by the rapid spread of power generation capacity from unpredictable renewable energy sources. Dynamic models of a 660 MW supercritical unit were established with the GSE software. The models have good accuracy with the error not more than ±0.5%. In this paper, the influence of the transient process of the unit load-up on denitrification and particle removal was studied. The results show that with the increase of unit load, the denitrification efficiency increases and the particle removal efficiency decreases gradually. During the load-up process, the transient stability time of denitrification is far less than the particle removal. At the same time, the denitrification efficiency of SCR shows a sudden decrease and then a rapid increase, and the efficiency of ESP firstly increases suddenly and then decreases to stable. When the amplitude of the load-up is large, SCR is prone to overshoot, resulting in NO_x excessive emission.