Effects of coal reburning on NO_x emission of a 600 MW utility boiler

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/m³ (O₂ 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.