Industrial test on coal re-burning at a 600 MW utility boiler and NO _x reduction

Abstract

This research conducts a series of industrial tests on coal reburning of a 600 MW pulverized coal boiler firing lignite, which is one 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 is reduced by 65.36%. In the meanwhile, loss of ignition (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 proportion of the reburning coal, the higher the NO _x control can reach.