Removal of pollution from the chemical looping process: A mini review

The chemical looping process (CLP), a technology that is completely different from the traditional heat utilization of fuel, has gained widespread attention not only for zero-CO2 emissions and cascade energy utilization but also in the field of pollution removal. Due to the low reaction temperature and N2-free reaction atmosphere, the property of low NOx emission was found in the early days of the technology's development. In CLP, oxygen carriers (OCs) can also remove tar through catalytic cracking, remove pollutants containing S/Cl by reacting with S/Cl to form metal compounds, and promote the conversion of Hg0 to Hg2+ through catalytic oxidation to promote subsequent removal of Hg. Recent advances in the removal of tar- and nitrogen-, sulfur-, chlorine- and mercury-containing pollutants in CLP are reviewed in this paper. On the basis of these findings, the effects of various oxygen carriers, additives and reaction conditions on the removal of various pollutants are discussed. Due to its environmental friendliness and low price, Fe-based OCs, especially Fe-rich natural ores and solid wastes, are the most promising for practical application. It is hoped that the synergistic removal of pollution can be achieved by loading a Cl/S absorbent and active metal oxides on OCs.

Automated summary

The chemical looping process (CLP) technology has shown promise in reducing emissions and removing pollutants by achieving zero-CO2 emissions and utilizing cascade energy. Fe-based oxygen carriers are considered the most promising materials for practical application in pollutant removal, showing significant potential in environmental protection.