Chemical looping gasification of biochar to produce hydrogen-rich syngas using Fe/Ca-based oxygen carrier prepared by coprecipitation

Abstract Biochar chemical looping gasification (CLG) is a novel technology to obtain hydrogen-rich syngas, high gasification efficiency and low carbon deposition. This study investigates the effect of preparation methods, Fe loadings, active components, Ca loadings and steam/biochar (S/C) to achieve the optimal oxygen carrier. The results show that coprecipitation is the best preparation method to gain highest efficiency, redox activity and dispersion. H2 production increases visibly with the increase of Fe loading, while efficiencies increase firstly and then decrease. There is an evident effect of active component on CLG. Oxygen carrier based on Fe/Ca performs a lower carbon deposition, higher H2 production and efficiency. With the increase of Ca loading, H2 production and efficiencies increase firstly and then decrease. S/C has an obvious effect on CLG performance. 1.5 is the optimal S/C to achieve high H2 concentration of 67.35%, the highest gas production of 1.34 Nm3/kg and gasification efficiency of 96.93%.