CPFD simulation on biomass-coal co-firing characteristics in an industrial CFB boiler for S-CO2 power cycle

Combining supercritical carbon dioxide (S-CO 2 ) power cycle with biomass-coal co-firing is a clean, high-performance pathway for thermal power plants, yet relevant experiments and simulations remain challenging. In this study, a 3D gas-solid reaction-coupled mathematical model is developed, and full-loop simulations of a 100 MW S-CO 2 CFB boiler are performed using MP-PIC method to investigate effects of biomass blending mass ratio (0∼50%) on co-firing performance, pollution emissions, and boiler efficiencies. Results reveal that the biomass-coal co-firing weakens the core-annulus flow structure and shifts local high-temperature and cold-wall heat flux zones downward. Increasing biomass blending mass ratio reduces CO 2 , NO, and SO 2 , emissions, slightly raises CO and N 2 O emissions, and improves boiler efficiency, with 30% biomass ratio acting as the inflection point. Compared with conventional water steam power cycle, the S-CO 2 power cycle increases furnace temperature by 59.54 K, achieves relative emission reductions of 22.9% for CO 2 and 15.6% for CO, and absolute emission reductions of 159 ppm for NOx and 26 ppm for SO 2 , and yields efficiency increments of 5.1% in carbon conversion, 5.5% in self-desulfurization efficiency and 0.65% in combustion efficiency, providing theoretical foundation and technical reference to industrial applications of S-CO 2 biomass-coal co-firing.