Performance of CaMn0.625Ti0.125Fe0.125Mg0.125O3 Oxygen Carrier in the Chemical Looping Combustion of Biomass

Chemical looping combustion (CLC) has been recognized as a promising CO2 capture technology, in which oxygen carriers (OCs) transport lattice oxygen to the fuel instead of the air. This study aims to evaluate a newly developed perovskite OC for biomass CLC and to clarify the role of staged fuel conversion in improving gas–solid redox efficiency. This is the first application of perovskite OC CaMn0.625Ti0.125Fe0.125Mg0.125O3 in biomass CLC using a dual-stage fluidized bed. The perovskite OC was synthesized via a solid-phase synthesis method, and its performance in a dual-stage fluidized bed reactor was evaluated using pine wood chips and furfural residues as model solid fuels. The in situ conversion of volatile compounds and gasification products derived from the two biomass types was comprehensively studied. The effects of operational parameters, including temperature, OC-to-biomass ratio, and gas flow rate, on the combustion efficiency and CO2 yield were examined. Results showed that separated gasification–combustion enhanced the combustion efficiency and CO2 yield. At 950 °C, an OC-to-pine chip ratio of 100:1, and a gas flow rate of 0.7 L/min, the maximum combustion efficiency and CO2 yield of 79% and 82% were obtained, respectively. Moreover, under the optimal gasification conditions (gasification rate > 99%), increasing the fuel concentration resulted in an increase in the oxygen release from 0.21 g to 0.40 g. Concurrently, the corresponding total oxygen demand increased from 4.34% to 10.56%, indicating the suitability of CaMn0.625Ti0.125Fe0.125Mg0.125O3 in the CLC of biomass.