热一次风做高速燃尽风的燃煤锅炉低NOx燃烧改造试验

The retrofit experiments for reducing NOx emission on coal fired boiler by using primary air as high-speed over-fired air

为了优化锅炉运行,降低炉内NOx排放量,对某现役350 MW机组锅炉利用富余一次风作为高速燃尽风的改造进行了现场试验,得到改造前后脱硝系统入口处的温度场分布和燃烧产物的组分浓度分布,分析了高速燃尽风对脱硝入口温度场、CO场、O2场和NOx场的影响。结果表明:高速射流燃尽风投用后,锅炉燃烧效率和改造前基本一致,炉膛出口温度分布和氧量分布都较为均匀,NOx排放量明显降低。改造后NOx(折算到6%氧)为364.65 mg/m^3(ABCD四磨同时运行的100%负荷下)和242.60 mg/m^3(ABC三磨同时运行的75%负荷下),比改造前约降低了33~53 mg/m^3,说明高速燃尽风技术能切实有效地深度降低NOx。

In order to optimize the operation of boiler and reduce NOx emission,retrofit tests were carried out on a 350 MW unit boiler which used surplus primary air as high-speed over fired air.The temperature field distribution and the concentration distribution of combustion components at the entrance of denitrification system were obtained before and after the transformation.The effects of high-speed over fired air on the temperature field,CO field,O2 field and NOx field at the denitrification entrance were analyzed.Results show that the combustion efficiency of the high-speed jet is basically the same as before,the temperature distribution and oxygen distribution at the furnace outlet are uniform,and the emission of NOx is obviously reduced.After the transformation,the NOx(converted to 6%oxygen)is 364.65 mg/Nm^3(100%load)and 242.60 mg/Nm^3(75%load),which is about 33-53 mg/Nm^3 lower than before the retrofit,indicating that the high-speed exhaust air technology can effectively and deeply reduce NOx.