Abstract: Coal-fired power plants are the major source of NOx generation and emission. The analysis on the operating status of a 600-MW coal-fired boiler reveals three problems, high NOx emission concentration, low denitrification equipment utilization factor and uneven SCR concentration distribution. To address the high NOx emission concentration problem,, the low NOx burner is adopted; to increase the utilization factor of the denitrification equipment, boiler combustion is adjusted and controlled low temperature denitrification operation is carried out; to improve the distribution uniformity of SCR concentration, the denitrification AIG ammonia injection system is adjusted and optimized. As the result, the concentration of NOx emission is reduced from 450~650 mg/m3 to 280 mg/m3; the utilization factor of denitrification equipment is increased from 55% to 99.5%; the concentration distribution uniformity is improved and the denitrification efficiency is increased by 3%. Therefore, with other NOx emission control measures applied simultaneously, the general NOx control level is enhanced significantly, which proves the feasibility of controlled low-temperature denitrification.

Key words: flue gas denitrafication, low NOx burner, low-temperature SCR denitrafication operation