660 MW燃煤机组瞬态过程NOx生成及脱除特性

燃煤机组为完成电网负荷调峰任务，锅炉负荷长期频繁波动，对氮氧化物的生成及脱除效果有显著影响。以某660 MW燃煤机组瞬态过程氮氧化物的生成及脱除特性为研究目标，建立了机组瞬态过程氮氧化物生成预测模型，开展了变负荷过程中氮氧化物生成预测研究。针对燃煤机组变负荷过程燃烧器切换的特点，发现新增燃烧器的负荷点越高时，越能有效避免氮氧化物的生成值增大。另外，分析了选择性催化还原（selective catalytic reduction，SCR）动态特性，分别研究了SCR入口氮氧化物浓度、喷氨浓度、烟气流速和反应温度等阶跃变化对氮氧化物脱除的动态特性影响，为后续瞬态过程喷氨优化控制逻辑提供参考。

Characteristics of NOx Formation and Removal in the Transient Process of a 660 MW Coal-fired Power Unit

In order to complete the peak load regulating of power system, coal-fired power units have long-term frequent load fluctuations, which have a significant impact on the formation and removal of nitrogen oxides. In this paper, with the goal of studying the characteristics of nitrogen oxide generation and removal in the transient process of a 660 MW coal-fired unit, a prediction model of nitrogen oxides generation in the transient process was established, and the nitrogen oxides generation prediction study in the process of variable load was carried out. According to the characteristics of the burner switching in the variable load process of the coal-fired unit, it was found that the higher load point of the newly added burner, the more effectively it can avoid the increase of the generation value of nitrogen oxides. In addition, the dynamic characteristics of selective catalytic reduction (SCR) were analyzed, and the effects of the step changes such as nitrogen oxide concentration, NH₃ injection concentration, flue gas flow rate and reaction temperature on the dynamic characteristics of nitrogen oxides removal were studied respectively, which provides a reference for the optimization control logic of NH₃ injection in the subsequent transient process.