Effects of Secondary Air on Flow, Combustion, and NOx Emission from a Novel Pulverized Coal Burner for Industrial Boilers

This paper deals with an experimental investigation on the performance of a novel pulverized coal burner, featuring the introduction of an outer secondary air without swirling, as applied to an industrial boiler. Both cold air and combustion tests were conducted to investigate the effects of the secondary air on flow, combustion, and NOx emission from this novel burner. The measured flow fields, temperature distributions, and gas concentrations were presented. It was shown that, due to the presence of the outer secondary air, slagging in the adiabatic combustion chamber could be avoided and a NOx emission level of 600 mg/Nm3 was realized. In addition, the operating efficiency of the boiler was found to be greater than 89.50%, which was higher than that of the conventional industrial boilers.