Numerical Simulation of NOx Emission Characteristics of a Horizontal Bias Combustion Burner

摘要

Horizontal Bias Combustion burner (HBC burner) is introduced to reduce NO emission from combustion process in the furnace. A louver concentrator is installed to change particle concentration ratio of rich to lean stream, R_n, by adjusting inclining angle of louver blades. A comprehensive pulverized coal combustion model is employed to simulate the combustion process of a HBC burner in a tangential firing furnace. Eulerian-Eulerian technique of 'interpenetrating continua' is employed to establish a complete set of conservation equations for mass, momentum and energy of gas-particle phases, which are solved by the finite volume codes. NO production and reduction are modeled by a simplified mechanism including the middle reactant HCN. The first two simulation cases were under uniform secondary air (SA) distribution, while blade angle was changed from 0° to 32°. The other two cases were under staged SA distribution, while blade angle was changed from 0° to 32°. Simulation results show that, under the uniform SA distribution, the NO emission reduces slightly from 0° to 32°. However, NO declines a large extent from 0° to 32° under staged cases, which agrees with the experimental results. It can be concluded that NOx emission from HBC burner is greatly influenced by the atmosphere condition near burner nozzles, and HBC burner reduces NO emission under staged SA supplying.