NOx emission from a 300 MW unit boiler was relatively high.Thus,low NOx combustion retrofitting was performed.Countermeasures include adopting the low NOx coal burners,arranging reasonable separated over fire air, improving the tertiary air burner and compact over air (OFA)nozzle,and presetting the auxiliary air nozzle with horizontal angles.After the transformation,under condition with nearly no change of the desuperheating water quan-tity,the temperature of superheated and reheated steam kept stable.With the same excess air ratio,the NOx emission decreased by about 30%,the combustible matter content in fly ash and slag reduced,and the combustion efficiency increased.%针对某电厂300 MW 机组锅炉 NOx 排放浓度较高问题，采取采用低 NOx 煤粉燃烧器、设置合理的分离燃尽风、改进三次风燃烧器及紧凑式燃尽风（OFA）喷口、预置水平偏角的辅助风喷口（CFS）等措施对其进行了低氮燃烧改造。改造后在减温水量无明显增加的情况下，过热、再热蒸汽温度保持稳定，同样过量空气系数下，NOx 排放浓度降低30％左右，锅炉飞灰可燃物、炉渣可燃物均有不同程度的降低，锅炉燃烧效率有所提高。
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