Fuel-nitrogen conversion in staged combustion of a high nitrogen petroleum fuel

Abstract

A theoretical and experimental study was carried out to determine lower bounds of NOx emission from staged combustion of a 0.7% N No. 6 fuel oil. Thermodynamic and chemical kinetic calculations have shown minimum NOx emissions at fuel rich stage equivalence ratios between 1.6 and 1.8 and fuel rich stage temepratures in the range of 1900 to 2100 K. Experiments carried out using the M.I.T. Combustion Research Facility at 1 MW (Thermal) input in the staged combustion mode have led to NOx emissions of 80 ppm at 3% O2 in the range of fuel rich stage equivalence ratios of 1.5 to 1.7, veryclose to that predicted from the model. The temperature effects shown in the model calculations could not be tested because the maximum temperatures in the experiments (1800 K) fell short of those required by the model. The good qualitative agreemement between model and experiment indicates the major role that gas phase chemical kinetics play in the conversion of fuel nitrogen to NOx and N2 respectively.