600MW超临界锅炉低氮燃烧器改造

山西古交兴能电厂600 MW锅炉投产运行后,出现了锅炉NOx排放量一直高于原厂设计值和两侧屏过下部、炉膛中上部水冷壁严重高温腐蚀现象,严重影响了锅炉的安全经济稳定运行。测试分析结果为燃烧器布置、低氮性能以及燃煤含硫量较高所致,为此于2013年对25台燃烧器进行了低氮改造,改造后的燃烧器实现了中心浓、四周淡的浓淡分级,配合带"扳边"结构的内外二次风,有效地推迟了燃烧器早期的风粉混合,抑制了NOx生成,使NOx排放量由521.9~629.6 mg/m3下降为408.6~440.9 mg/m3。同时有效地防止了煤粉被甩到水冷壁上,增强了水冷壁附近的氧化性气氛的覆盖范围,防止了两侧墙水冷壁因实现炉内水平空气分级后导致主燃区过量空气系数降低而产生的高温腐蚀问题。

Low NO_x Burner Transformation of the 600 MW Supercritical Boiler

After going into operation,the NOxemission of the 600 MW boiler in Shanxi Gujiao Xingneng Power Plant has been higher than the original design value.And there is serious high temperature corrosion in the lower part of the screen and the middle-top water wall in the furnace.These causes affect the safe economical and stable operation of the boiler.By test analysis,it is due to the poor burner arrangement ＆ low NOxperformance and high sulphur content in the fire coal.So a low nitrogen transformation was implemented to 25 burners in 2013.After the transformation,the burners effectively delay early mixture of the wind powder,inhibit the NOxformation,make the NOxemission drop from 521.9 629.6 mg/m3to 408.6-440.9mg/m3.A the same time pulverized coal is prevented from being thrown on the water cooling wall,enhancing the coverage range of the oxidizing atmosphere near the water cooling wall.All the measures may reduce the high temperature corrosion caused by lowering excess air coefficient in the main combustion zone.