Boosting Agroforestry Waste Valorization: Red Mud Oxygen Carriers with Tailored Oxygen Release for Enhanced Chemical Looping Gasification

In this study, red mud oxygen carriers were obtained by varying the preparation temperature and characterized using XRD, SEM, BET, and H2-TPR. The results showed that the oxygen carrier prepared at 1000 °C exhibited high reactivity due to clear grain boundaries, uniform size, high porosity, and smooth grain morphology. Additionally, the release of oxygen was accelerated, as indicated by the H2-TPR results. The water hyacinth, an aquatic plant of agroforestry waste, was selected as the research object, and the chemical looping gasification (CLG) reaction performance with prepared red mud carriers was investigated. The experiment results showed that the total gas yield (Yg) of the carriers prepared at 1000 °C reached a maximum of 1.02 Nm3/kg, had a high low-level heating value (LHV) of 12.06 MJ/Nm3, cold gas efficiency (CGE) of 91.49%, and carbon conversion rate (ηc) of 82.65%. This indicated that the red mud carriers synthesized at 1000 °C have a faster oxygen release rate, more concentrated oxygen release, and stronger reaction activity.