【摘要】 阐述了煤粉燃烧过程中NOx的生成机理,同时介绍了水平浓淡燃烧技术的思路和低NOx排放的原理。利用一种新型的二次风喷口水平摆动的水平浓淡风煤粉燃烧器对一台300 MW燃贫煤锅炉进行技术改造,并对影响NOx排放量和飞灰可燃物含量的各种因素进行了现场试验研究。通过试验,得到了一次风速、油二次风挡板开度、二次风配风方式、二次风水平摆角、燃尽风的投运、煤粉火嘴的切换、以及炉膛出口氧量等运行参数对飞灰可燃物含量和NOx排放的影响规律。试验结果表明,水平浓淡燃烧技术能大幅度降低NOx的排放量,同时能够保持较高的燃烧效率及很强的低负荷稳燃能力。更多还原

【Abstract】 The mechanism of NOx formation in pulverised coal combustion is introduced in this paper. The concept of horizontal bias combustion(HBC) and its principle of reducing NOx emission are also described. In situ experimental studies were made on the NOx emission and unburnt carbon loss in a 300 MW lean coal fired boiler, which adopted a new kind of HBC burner with the side secondary air(HBC-SSA) and the horizontally offset secondary air nozzles. Effect of operational parameters, such as the primary air(PA) velocity, the oil secondary air(SA) damper percentage, the SA distribution, the SA horizontally offset angle, the OFA, the PA and coal mixture switching, and the furnace excess air on unburnt carbon in fly ash and the NOx emission were obtained. Experimental results show that horizontal bias combustion can greatly decrease the emission of NOx while keeping high combustion efficiency and outstanding flame stability under low load without supporting fuel oil.更多还原