Conversion of Fuel Nitrogen to NOx in a Compact Combustor

Abstract

A low-nitrogen fuel, ASTM Jet A aviation kerosene, was doped with increasing amounts of pyridine as a means of increasing the content of chemically bound nitrogen, then burned at a rate of 50 lb/hr in a compact combustor incorporating staged air admission with a rich primary zone, and water cooling of the walls. Each increase in fuel nitrogen content resulted in a significant increase in NOx in the combustion products, and it is estimated that as much as 90 percent of the fuel nitrogen was converted to NOx at very low nitrogen levels, decreasing to 55 percent conversion at higher levels. These results are consistent with data reported for large steam boilers and for small residential boilers. It appears that emission standards requiring very low levels of NOx emission will require use of fuels with very low nitrogen content.