410t/h煤粉炉乏气送粉改造降低NO_x排放的试验研究

针对某电厂410 t/h煤粉炉在300 t/h以上高负荷下运行时NOx排放无法达标的问题,提出了将原中储式温风送粉系统改造为乏气送粉系统,技术方案为排粉风机出来的乏气全部送入一次风管道,直接采用乏气作为送粉介质输送煤粉,避免乏气直接送入炉膛造成的局部富氧气氛,从而有效抑制乏气中的煤粉燃烧NOx生成量。试验及调试结果表明,采用乏气送粉改造后,锅炉燃烧稳定、热效率未受影响,NOx排放降低到100 mg/m3以下(折算到氧量6%)。

Experiment study and analysis of pulverized coal boiler retrofitted by exhaust gas coal sending to decrease the NOx emission

Middle storage pulverized coal feed system with warm air of 410 t /h PC boiler was retrofitted by exhaust gas coal sending system to solve the problem of NOxemission when the boiler operating at higher than 300 t /h boiler load,with the characteristic as follows： the exhaust gas from powder exhaust fan,as powder sending medium,entered into the primary air piping to sending the pulverized coal,which avoid the partial rich-oxygen atmosphere and inhibit effectively the NOxproduction in combustion process. The experiment and research results showed that the steady combustion and constant thermal efficiency of the boiler after retrofitted and NOxemission was decreased below 100 mg /m^3（ convert to oxygen content of 6%）.