Predicting NOx emissions of a burner operated in flameless oxidation mode

This paper deals with the technology of burning natural gas with combustion air preheated to 1300 degreesC. The objective of this work is to assess the potential of several combustion models and NOx postprocessors for their abilities to predict NOx emissions. The steady-state computational results have been compared both with in-furnace measurements and with the measured furnace exit parameters. The following main conclusions have been drawn: (1) with the exception of the small region located within the natural gas jet, the computations resulted in good quality predictions; (2) the NOx has been formed in a thin elongated region (flamelet) located between the natural gas jet and the air jet; (3) the No has been formed mainly by the thermal path, and the NO-reburning mechanism was of little importance; and (4) there are strong indications that the non-stationary behavior of the weak (fuel) jet must be accounted for if the predictions within the fuel jet were to, be perfected.