Two-phase reaction characteristics in hybrid filtration combustion reactor gasification: Syngas ratio control through steam-oxygen balance

This study developed a gasification model for hybrid filtration combustion reactor using CFD approach. The effects of the H₂O/O₂ ratio (0.5–4), wall temperature (adiabatic and 1050–650 K), and varying thermal conductivities of inert porous media (1, 5, 20, 60, and 200 W/(m·K)) on two-phase reaction characteristics were investigated. The results show that steam enhances the reaction rates of the Steam-carbon and Water-gas shift reactions, promoting H₂ production while suppressing CO formation, ultimately achieving targeted CO₂ enrichment through combustion. Changes in the H₂O/O₂ ratio effectively regulate the H₂/CO ratio, with the syngas ratio increasing from 0.31 to 55.96 as the steam content in the feed increases, corresponding to a 17,841.83 % increase. The effect of wall temperature on syngas ratio regulation is less significant compared to the H₂O/O₂ ratio, with CO gradually increasing along the bed height in lower wall temperature conditions, making it difficult to maintain. However, an adiabatic wall significantly extends the Boudouard reaction zone. Variations in the thermal conductivity of inert porous media have minimal impact on the flue gas composition. Radiation enhances the sensitivity of the syngas ratio to changes in the H₂O/O₂ ratio, with the syngas ratio increasing from 0.20 to 0.91 when radiation is neglected, showing a significant decrease by 80.10 % compared to the scenario when radiation is considered. Furthermore, radiation heat transfer greatly suppresses CO formation, with the CO content in the flue gas increasing by 43.70 % to 6001.25 % as the H₂O/O₂ ratio rises.