Numerical simulation of combustion characteristics and NOx emission in a 330 MW power plant boiler with self-sustaining internal combustion burner

Nitrogen oxides (NOX) emitted from coal-fired power plants are one of the primary sources of NOX in the atmosphere. More stringent requierements on NOX emissions are implemented in laws focusing on the environmental protection. The self-sustaining internal combustion (SSIC) burner can stably preheat the pulverized coal and produce reducing atmosphere, effectively reducing NOX emissions, but the SSIC burners are still not widely used in industrial boilers. The SSIC burner is being used on a 330 MW tangentially-fired boiler to reduce NOX emissions from the boiler and improve stabilized combustion performance. The effect of the SSIC burner on the flow, combustion and NOX emission characteristics of the boiler are investigated by numerically simulating the boiler before and after retrofit at different loads (100% and 70%). The findings indicate that the initial NOX emission at the outlet is reduced by 24.77% and 27.18%, respectively, when the boiler with SSIC burner is operated at 100% and 70% loads. The combustion stability is improved and the pulverized coal burnout rate is increased by 2.22% and 2.46%, respectively. The NOX emissions of the boiler with the SSIC burner is reduced to 91.73 mg/Nm3 at 70% load. The SSIC burner employed in the 330 MW tangentially fired boiler has been shown to achieve effective NOX reduction and can be adapted to the changing demands of the boiler load. This study offers beneficial guidance for the practical implementation of SSIC burners on industrial power station boilers.