600MW机组对冲燃烧锅炉低氮燃烧改造及运行调整

摘要

For the high NO.duscharge density of 600 MW opposed wall firing boiler,the retrofitting of combustors with low NOx was carried on. By replacing low NOx burner,arranging OFA appropriately, and adopting staged-air furnace combustion technology, the NOx discharge density was decreased to 300 mg/m3.The unburned carbon mass fraction in fly ash was not changed greatly.By replacing parts of the low-temperatuer superheater with the economizer, the desuperheating water flow of superheater was reduced,the gas temperature in air preheater outlet was decreased and teh echaust gas temperature of boiler was decreased.All of these are good for improving the boiler efficiency.After the replacing of parts of the low-temperature superheater with the ecoomizer, the water temperature of economizer outlet wasd increated .But the under-saturationg temperaturae difference and the safety margin still exist.%为解决600MW火电机组对冲燃烧锅炉NO,排放质量浓度过高的问题,进行了低氮燃烧改造.通过低氮燃烧器更换,合理布置燃尽风喷嘴,采用全炉膛分级燃烧技术,使NOx排放质量浓度降低至300mg/m3左右,达到了降低NOx排放的效果,同时锅炉飞灰含碳质量分数没有明显的变化.通过部分低温过热器置换为省煤器.降低了过热器减温水流量,同时空气预热器进口烟气温度下降,锅炉排烟温度也会随之下降,有利于提高锅炉热效率.部分低温过热器置换后省煤器出口水温提高,但还有一定的欠饱和温差,距汽化仍有一定的安全裕度.