RELATIVE CONTRIBUTIONS OF VOLATILE NITROGEN AND CHAR NITROGEN TO NOX EMISSIONS FROM PULVERIZED COAL FLAMES

Special experimentation on a laboratory combustor allowed determination of relative contributions of volatile NO and char NO to total fuel NO emissions from self-sustaining pulverized coal flames. Volatile nitrogen conversion was deduced from data from coal flames both with and without addition of volatile nitrogenous compounds in the fuel jet. Char nitrogen conversion was measured from char combustion studies. It was concluded that under typical self-sustaining flame conditions about 50% of the coal nitrogen remains in the char, that volatile nitrogen conversion to volatile NO is the major contributor to NOx emissions, and that volatile NO is amenable to control by changes in burner aerodynamics while char NO is not. However, some combustion modifications do also cause changes in nitrogen distribution between char and volatiles. Changes in pyrolysis temperature alone are insufficient to cause drastic changes in NO emissions. © 1979, American Chemical Society. All rights reserved.