Knowledge Bank

Coal, an abundant and stable energy source, is playing an important role in current and future global energy supplies. Therefore, there is intensive research currently focusing on coal-conversion in a high-efficiency and environmentally-friendly way. The Chemical Looping Processes (CLPs) developed at The Ohio State University, can achieve H2 and power generation from coal with 100% CO2 capture. It uses Fe-based particles (Fe2O3) as oxygen carrier to capture and release oxygen in a cyclic manner, while coal-derived syngas (CO + H2) can be converted into high-temperature heat for power generation with 100% CO2 capture. It is widely believed that particle sintering is the main reason that cause of morphological deterioration and reactivity decay of pure Fe2O3 solids. Hence, most current efforts are put on anti-sintering and optimization of reaction condition. In this study, the exact solid deactivation mechanism was explored in order to achieve optimal particle development strategies. Reaction time, reaction temperature, and reduction-oxidation reaction cycle were the three factors studied to examine their individual effects on the resulting solid properties. The data showed that longer reaction time, lower reaction temperature, and multiple cyclic reactions would decrease a particle’s surface area, pore volume, and corresponding reactivity. This structural change is a complex process which involves multiple factors in the cyclic reaction, such as the solid’s inherent properties, solid-phase ionic transfer, and reaction condition. This study provides a better understanding of the deactivation mechanism of Fe-based chemical looping particles. It also has a pronounced influence and instructive significance to the future of particle development.