Steam-Free Gasification of Corn Straw for Enhanced H2 and CO Production Enabled by the Synergy of Ca(OH)2 and Fe2O3

Converting lignocellulosic biomass to syngas represents a promising way to integrate renewable hydrogen and carbon resources into sustainable carbon-neutral energy systems. However, the conventional biomass gasification process typically relies on excessive steam input, resulting in significant energy penalties and CO 2 emissions. This study proposed a novel integrated gasification process for syngas production from straw, featuring the self-reforming of straw volatiles and utilization of process CO 2 , enabled by the cooperation of Ca(OH) 2 and Fe 2 O 3 . The contents of Ca(OH) 2 and Fe 2 O 3 were optimized to direct straw hydrogen into the volatiles and straw carbon into the solid phase during pyrolysis, thereby facilitating subsequent H 2 and CO production. The cooperation of Ca(OH) 2 and Fe 2 O 3 was manifested in two aspects: generating in situ steam for the self-reforming of volatiles into H 2 and promoting the secondary conversion of biochar and process CO 2 into CO. The optimized C0.3F0.2 reached a syngas yield of 19.3 mmol/g straw with a H 2 selectivity of 35.8% and a CO selectivity of 28.0%. 34.8% of process CO 2 was captured and utilized as CO rather than emitted. This work provides a sustainable and eco-friendly way for converting the hydrogen and carbon resources into efficient syngas production and falls in the domain of carbon-neutral energy system development.