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对某300 MW四角切圆锅炉低氮改造前后NOx的生成特性进行了数值计算,分析了低氮改造对NOx生成特性的影响.结果表明:原有双通道自稳燃型燃烧器稳燃腔的设计明显加速了热力型NOx的生成;新型水平浓淡燃烧器浓侧和淡侧煤粉均处于偏离化学当量比条件下燃烧,喷口附近火焰温度明显降低,有利于控制热力型NOx的生成,缺氧燃烧降低了煤粉的燃烧效率,冷灰斗区域及三次风以上区域燃料型NOx的生成速率有所增大.
The formation characteristics of NOx before and after low nitrogen retrofit of a 300 MW square tangentially fired boiler were numerically calculated and the effect of low nitrogen retrofit on the formation of NOx was analyzed.The results showed that the combustion stability of the original dual- The design significantly accelerates the formation of thermal NO x. The pulverized coal rich in both horizontal and lean burners ignites at a stoichiometric ratio, and the flame temperature near the nozzle decreases significantly, which is beneficial to control the generation of thermal NOx, Combustion reduces the combustion efficiency of the pulverized coal, and the formation rate of fuel NOx in the cold hopper zone and the area above the tertiary air shaft increases.