Redox performance of pyrite cinder in methane chemical looping combustion

The oxygen carrier plays a vital role in chemical looping combustion. Development of low-cost oxygen carriers is of great significance to the engineering application of chemical looping techniques. In this study, pyrite cinder, a byproduct from the process of sulfuric acid production, was used as an oxygen carrier in CH4 chemical looping combustion. The purpose of this research is to analyze the redox performance of pyrite cinder in a fixed-bed reactor using 5% CH4-95% N-2 as reducing gas. The other two natural Fe-based oxygen carriers (hematite, ilmenite) were used as references. The results showed that the highest CO2 selectivity and CH4 conversion were found for pyrite cinder during 20 redox cycles. Tests at different reaction temperatures were also conducted to study the influence of reaction temperature on the redox activity of pyrite cinder. The characterization analysis of SEM presented that the surface microstructure of pyrite cinder could maintain stable, which indicated that pyrite cinder possessed high anti-sintering ability in redox cycles. This study gives a research basis for the application of pyrite cinder in chemical looping combustion.