Experimental study on NOx generation and emission characteristics of layer combustion of peanut shell briquette fuel

This study aimed to reduce NO_x generation and emissions during the combustion of biomass in boilers. The variations in gas-phase composition and NO generation of peanut shell briquette fuel were investigated using a unit layer combustion test platform under five working conditions with air supply rates ranging from 30 to 70 Nm³/h. The experimental results showed that the average concentration of NO in the ignition zone was significantly higher than that in the combustion zone, while the oxidation zone covering the reduction layer exhibited the lowest average NO concentration. An innovative segmented combustion characteristics model for peanut shell pelletized fuel was developed using the temperature-dependent gas phase composition method. Based on the analysis of the NO reduction effect in the coke reduction layer, the optimal scheme was identified at an air supply rate of 60 Nm³/h (α = 1.08), where the average NO emission concentration, adjusted to 9 % O₂, was 281.75 mg/m³. These findings provide a theoretical basis for achieving low-nitrogen combustion in peanut shell briquette fuel.