Coupling biomass gasification and inline co-steam reforming: Synergistic effect on promotion of hydrogen production and tar removal

Biomass to green H2 is a promising strategy to achieve clean energy. This study proposed a novel concept of enhancing H2 production and tar removal via biomass gasification coupled with inline co-steam reforming (BGCSR) process. Varying gasification/pyrolysis biochar materials (G/PCMs) were applied assisted-reforming agents and co-reactants at the steam reforming stage in the BGCSR process. First, four representative biomass categories (wheat straw, microalgae, sewage sludge, and cow manure) were subjected to BGCSR process. Microalgae presented the more positive synergistic effect on H2 production and tar reduction. It was noticed that microalgae subjected to BGCSR in the presence of G/PCMs showed the comparable H2 concentration (over 56 vol %). The highest cumulative gas yield (104.17 mmol/g) and H2 yield (59.55 mmol/g) were manifested in the presence of C[F900], with the highest synergistic effect of 16.02% and 19.74%, respectively. C[F900] also presented the most significant synergistic effect (13.81%) on tar elimination. There outcomes were in relation to the properties of G/PCMs, e.g., elemental compositions, inherent alkali and alkaline earth metals (AAEMs), and surface functional groups. In addition, reaction mechanism regarding BGCSR was elucidated. Overall, this study provided a novel and effective way to valorize biomass into H2-enriched gas whilst minimizing tar formation.