锅炉低负荷运行时NO_(x)排放偏高的原因分析及调整措施

Cause Analysis and Adjustment Measures of High NO_(x) Emission During Low Load Operation of Boiler

某电厂采用四角切圆燃烧机组,由于需要长期低负荷运行,存在NO_(x)排放偏高的问题。通过研究NO_(x)生成机理以及实际降低NO_(x)排放的方法,提出降低NO_(x)排放的调整措施。通过对四角切圆燃烧机组实际燃烧调整,包括煤粉细度调整,过量空气系数调整,燃烧器一、二次风门及分离燃尽风风门调整,低负荷情况下不同燃烧器使用配合调整,控制炉膛内不同区域的过量空气系数。在保证燃烧稳定及锅炉效率的前提下大幅降低NO_(x)排放。验证分级燃烧降低NO_(x)排放的实际效果,对优化运行提供建议。

A power plant using tangentially firing unit needs long-term low load operation.There is a problem of high NO_(x) emission.Through the study of NO_(x) generation mode and practical methods of reducing NO_(x) emission,the adjustment measures to reduce NO_(x) emission are put forward.Through the actual combustion adjustment on the tangentially firing unit,including pulverized coal fineness adjustment,excess air coefficient adjustment,burner primary and secondary air valve and separate burnout air valve adjustment,coordination of different burners under low load adjustment,the excess air coefficient in different areas of the furnace is controlled.On the premise of ensuring combustion stability and boiler efficiency,NO_(x) emission is greatly reduced.The actual result of staged combustion on reducing NO_(x) emission is verified,and suggestions for optimal operation are provided.