Microwave-assisted chemical looping gasification of lignite coal for CO-rich syngas production

Chemical looping gasification (CLG) is a promising technology for the green conversion of coal, due to advantages such as enhanced CO₂ capture capacity, high resource utilization, and minimal environmental pollution, among others. In this study, microwave-assisted lignite CLG was investigated with Fe₃O₄ as the oxygen carrier, and the gasification performance was evaluated under different Fe₃O₄: lignite mass ratios (2:1, 3:1, 4:1, 5:1, and 6:1) and microwave powers (560, 660, 760, 860, and 960 W). The results showed that the CO yield initially rose and then fell as the Fe₃O₄ to lignite mass ratio increased, with the 5:1 ratio yielding the highest CO. Similarly, the CO yield first rose and then fell with increasing microwave power, reaching its peak at 860 W. The maximum values of CO yield, syngas yield, and carbon conversion reached 17.04 mmol/g lignite, 78.20 %, and 46.07 %, respectively, under the conditions of a 5: 1 Fe₃O₄: lignite mass ratio and 860 W microwave power. These results indicate that the microwave-assisted approach has great potential to improve the efficiency of lignite CLG.