The oxidation of ammonia during the combustion of ethane in a thermally stabilized burner (TS8) was studied in order to test the independence of the mechanism of fuel-NOxproduction on the type of nitrogen in the fuel. In a previous investigation of fuel-NOxproduction in the TSB using carbon-containing fuel-nitrogen compounds, nitrogen was found to be converted almost entirely to NOxat equivalence ratios near stoichiometric for post-flame residence times greater than 1.5 ms. This result was reproduced by the current study using ammonia as the fuel-nitrogen source. For fuel-rich stoichiometrics, NOxproduction from the ammonia was found to be a stronger function of post-flame residence time, with the peak in the concentration of NOxoccurring at about 1.5-2 ms after the flame front, and a moderate reduction thereafter. These results were confirmed theoretically using a plug-flow model for the TSB coupled with reaction mechanisms for ethane and ammonia oxidation. The fractional"conversion of ammonia to NOxas a function of equivalence ratio was otherwise found to compare closely with the prior results for complex carbon-bearing nitrogen additives.
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