CPFD simulation of combustion and emission characteristics of corn stalk and sludge in a CFB boiler

This study investigates the co-combustion of corn stalk and high-moisture sewage sludge in a 130 t/h CFB boiler via CPFD simulation. Its novelty is revealing how sludge blending ratio couples with combustion stability, temperature, gas components, and NO x /SO 2 emissions, supporting harmless sludge disposal and green energy utilization.The results demonstrated that the optimal sewage sludge blending ratio was 15% under conditions of 80% moisture content. The introduction of sludge significantly impacted furnace temperature; when the sludge blending ratio reached 20%, the local average temperature within the furnace dropped considerably below 1100 K, posing a significant quenching risk. Therefore, the blending ratio should be maintained within a reasonable operational window. However, outlet NO emissions showed variations within a 5% range, demonstrating co-combustion exerted only minor influence on NO release. Furthermore, the sludge incorporation ratio increased in the range from 0% to 30%, local O 2 mole fraction at the exit increased by 15%, while the CO 2 mole fraction decreased by 15%, mitigating localized oxygen-deficient conditions observed in the furnace. SO 2 emissions remained consistently low, with co-combustion showing no discernible effect on SO 2 release.