Numerical Simulation of a Serial Composite Gasification Process for Biomass and Coal

• • Optimal gasification temperature of 1100°C yields a hydrogen-rich gas with H2 concentration up to 14.8% (from coal pyrolysis) and CO concentration of 36.1%, enhancing the calorific value for power generation. • • At low steam-to-biomass mass ratio (SBR), gas-solid reactions in the dense phase are promoted, increasing carbon conversion by up to 15% compared to high SBR, which is critical for reducing unburned carbon in ash. • • High SBR enhances homogeneous reactions at the dilute phase outlet, boosting H2 yield by 20% but requiring careful heat management to avoid temperature drops below 800°C, which would reduce reaction rates. • • Biomass-to-coal mass ratio (BCR) should be maximized; a BCR of 0.022 kg/s biomass to 0.0045 kg/s coal (mass ratio ~4.9) achieves stable operation and gas composition, reducing fuel costs by up to 30% compared to coal-only gasification.