Microwave-assisted chemical looping gasification of sugarcane bagasse biomass using Fe3O4 as oxygen carrier for H2/CO-rich syngas production

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Chemical looping gasification (CLG) is a promising approach for sustainable biomass utilization. The selection of an appropriate heating method is a key challenge in the CLG process. This study investigated microwave-assisted CLG of sugarcane bagasse using Fe3O4 as an oxygen carrier. The effects of microwave power (580, 680, 780, 880, and 980 W) and oxygen carrier to biomass mass ratio (mOC:mSCB) (0:6, 1:5, 2:4, 3:3, 4:2, and 5:1) on product distributions, syngas compositions, syngas efficiencies, and syngas HHVs were studied. Results showed that with increase in microwave power and mOC:mSCB ratio, syngas yield, syngas efficiency, and syngas HHV initially increased and then finally decreased. The optimal conditions were found to be 880 W power and a 3:3 ratio. The optimal syngas yield of 88.23 wt% was achieved in the air reactor at 880 W with a 5:1 ratio. Pyrolysis yielded H2 and CO-enriched syngas, while gasification increased CO concentration. The highest CO + H2 concentration of 64.96 vol% was obtained in the fuel reactor at 880 W with a 3:3 ratio. The maximum thermal efficiency (49.55 %), cold gas efficiency (49.48 %), carbon conversion efficiency (54.42 %), and HHV (16.31 MJ/Nm3) were observed in the fuel reactor at 880 W and a 3:3 ratio. Microwave-assisted heating achieved an impressive heating rate of 1166.40 °C/min at 980 W and 5:1 in air reactor. This study shows that microwave heating can be utilized as efficient heating in CLG for sustainable biomass utilization.