低氮燃烧技术在燃煤锅炉上的应用

Application of Low NO_x Burner in Coal-fired Boiler

介绍了燃煤锅炉NO_x的生成机理和低氮燃烧技术。对经低氮燃烧技术改造的锅炉进行了低氮燃烧和热效率优化调整试验,分析了不同工况下锅炉热效率和NO_x排放情况。结果表明:锅炉低氮燃烧器改造后,炉膛出口氧含量为3.5%~4.0%,燃尽风门开度40%~50%,上下层二次风门开度85%,中层二次风门开度30%,下层二次风门开度65%,采用"束腰"型配风方式工况下,锅炉热效率达到91.83%,NO_x排放浓度为431 mg/m^3,可以较好地平衡NO_x排放与锅炉热效率之间的关系,有利于锅炉优化运行。

The NO_x formation mechanism and the low NO_x combustion technology used in the coal-fired boiler are introduced. The low NO_x combustion and the thermal efficiency in the boiler are optimized by adjustment tests. The thermal efficiency and NO_x emissions under different operating conditions are analyzed. The results show that, after the low NO_x burner is used, the thermal efficiency of 91.83% and the NO_x emission concentration of 431 mg/m^3 have been achieved when the oxygen content at furnace exit is at 3.5%-4.0%, the over-fired air damper position at 40%-50%, the lower and upper secondary air damper at 85%, the middle secondary air damper at 30%, the lower secondary air damper at 65%, and the ＂waist shaped＂ type air distribution is adopted. Therefore the relation between NO_x emission and thermal efficiency could be better balanced,beneficial to optimal operation of the boiler.