Numerical study of NOx emission in high temperature air combustion

The characteristics of NOx emission in the high-temperature air combustion technology were investigated numerically. Two kinds of methods were used. Detailed chemistry and transport properties were used for a two-dimensional laminar diffusion flame, and a simplified reaction scheme was used for calculating a turbulent flame in a furnace. Results show that the thermal mechanism dominates NOx emission in high-temperature air combustion. If only the preheated air temperature is increased, NOx emission will rise significantly. However, the combination of air preheating and flue gas recirculation not only improves the combustion efficiency, but also suppresses NOx emission in the combustion process.