Synthesis gas production from biomass gasification using steam coupling with natural hematite as oxygen carrier

Biomass gasification using lattice oxygen (BGLO) of natural hematite coupling with steam was conducted in a fluidized bed reactor. The presence of hematite particles evidently facilitated to biomass gasification. Comparing with biomass steam gasification (BSG), carbon conversion and gas yield increased by 7.47% and 11.02%, respectively, and tar content lowered by 51.53%, in BGLO with an S/B of 0.85 at 800 °C. In this case, 62.30% of the lattice oxygen in the hematite particles was consumed in the biomass gasification. The reaction temperature, steam-to-biomass ratio (S/B) and reaction time on the performance of hematite particles were extensively investigated, in terms of gas distribution, heating value, yield and carbon conversion. With the reaction temperature increasing from 750 to 850 °C, the gas yield increased from1.12 to 1.53Nm3/kg, and carbon conversion increased from 77.21% to 95.49%. An optimal S/B ratio of 0.85 was obtained in order to maximize the carbon conversion and gas yield of BGLO. At this ratio, the gas yield reached 1.41Nm3/kg with carbon conversion of 92.98%. The gas concentration was gradually close to that of BSG at the end stage of BGLO due to the active lattice oxygen was depleted with the proceeding of reactions.