Cellulose gasification with Ca–Fe oxygen carrier in chemical-looping process

Biomass-derived chemical looping gasification (BCLG) is a novel technology for lignocellulose energy applications. Ca–Fe oxygen carriers have been proven to be a potential material for efficient lignocellulose conversion and hydrogen-enriched syngas production in process studies. In this study, Thermogravimetry-mass spectrometry (TG-MS), pyrolysis chromatography-mass spectrometry (Py-GC-MS) and fixed-bed experiments were conducted, and the cellulose BCLG product was analyzed to explore the mechanism of reaction between Ca–Fe OCs and biomass char or volatiles. The mechanism of the synergistic effect of Ca–Fe was analyzed to explain the characteristics of the OCs. The results suggest the Ca-based materials act as catalysts to promote the decomposition of cellulose monomers at primary reaction and char at secondary reaction, and also promote the reforming and oxidation of volatiles by chemisorption. Ca participates in the construction of inert substances, such as Ca2Fe2O5, to avoid the deep oxidation of CO and H2. Fe-based material supplies oxygen and promotes the reforming of volatile. Compared with Fe2O3 and CaO/Fe2O3, CaFe2O4 shows a better performance on carbon conversion and H2 production below 850 °C.