煤粉再燃对600MW锅炉NO_x排放的影响

THE EFFECTS OF COAL REBURNING ON NO_x EMISSION OF A 600 MW UTILITY BOILER

在国内某台燃用褐煤的600 MW机组锅炉上进行了煤粉再燃技术示范并进行了工业试验。机组在600MW负荷下运行时,NO_x排放可控制在274mg/m^3(烟气中氧量折算到6%,下同)的水平,比改造前下降了65.36%,同时燃烧效率没有降低.进行了常规通风、空气分级和煤粉再燃三个工况下的试验,结果表明,煤粉再燃对NO_x的控制效果最好,其次为空气分级。再燃煤粉比例对NO_x排放也有明显的影响,在试验条件下,随着再燃燃料比例的增加,NO_x排放呈降低趋势。

This research conducts a series of industrial tests on coal reburning of a 600 MW pulverized coal boiler firing lignite,which is a part of a coal reburning demonstration project.When running steadily under 600 MW load,the boiler has an average NO_x emission of 274 mg/m^3(O_2 content in flue gas is converted to 6%),the NO_x emission reduces by 65.36%.At the same time,LOI under coal reburning rarely increases.Three operation conditions,traditional air feeding,air staging and coal reburning,are realized respectively during the industrial tests,and the results indicate that coal reburning has the lowest NO_x emission,while the traditional air feeding has the highest NO_x emission. Under the test conditions,the higher the reburn coal proportion,the higher the NO_x control.