600MW超临界旋流燃烧烟煤锅炉NO_x排放特性试验

Experimental study on the characteristics of NO_x emissions from 600 MW supercritical bituminous coal fired boiler with swirl burner

针对某厂1台600 MW超临界低NOx轴向旋流燃烧烟煤锅炉特点,通过变工况(氧量、不同层燃烧器风量分配方式、二次风比率、二次风旋流强度、三次风旋流强度、同层燃烧器风量分配方式和负荷等)试验,分析了锅炉NOx排放特性。试验结果表明:对于燃用烟煤的采用低NOx旋流燃烧器的锅炉,运行氧量、燃尽风份额、锅炉负荷及同层燃烧器风量分配方式是NOx排放的主要影响因素。为控制NOx排放,保持锅炉原有热效率,燃烧调整的原则为:(1)在保证锅炉运行安全的前提下应尽量采用低氧燃烧;(2)采用大比例的燃尽风份额;(3)运行负荷不应过低;(4)同层燃烧器风量分配采用双峰方式。

NOx emissions from a 600 MW supercritical boiler with swirl burner were investigated by performing a serial of tests such as changing O2 concentration,air-distribution of different level burners,secondary air ratio,secondary and tertiary air swirl strength,air-distribution of the burners in same level and boiler load.The test results show that for the bituminous coal fired boiler with swirl burner,the O2 concentration,over fire air(OFA) ratio,boiler load and air-distribution mode of the burners in same level are the main factors affecting NOx emissions.In order to reduce NOx emissions and keep higher boiler efficiency,the following principles about combustion adjustment should be obeyed:(1) the O2 concentration should be kept in the premise of ensuring safe operation of boiler as lower as possible;(2) large proportion of OFA should be adopted;(3) boiler load should not be too low;(4) two-peak air distribution mode should be taken among the same level burners.