Chemical Looping Combustion of Coal with Iron Oxide Oxygen Carrier for Inherent CO2 Separation

Abstract

Chemical looping combustion has emerged as an advanced clean energy technology for efficient fuel conversion with inherent carbon dioxide separation and reduced greenhouse gas emissions. The present study investigates the chemical looping combustion of coal using iron oxide as an oxygen carrier, with emphasis on combustion performance, oxygen transfer capability, and carbon dioxide capture efficiency under controlled operating conditions. Experimental analysis was conducted to evaluate the influence of reaction temperature, fuel composition, oxygen carrier circulation, and reduction–oxidation cycles on combustion characteristics and process stability. Iron oxide-based oxygen carriers were selected due to their high oxygen transport capacity, thermal stability, low cost, and environmental compatibility. Results demonstrate that the oxygen carrier effectively transfers lattice oxygen to coal during the fuel reactor stage, enabling efficient combustion without direct contact between air and fuel, thereby producing a concentrated carbon dioxide stream suitable for sequestration or utilization. The study further reveals that elevated operating temperatures significantly enhance coal conversion, reaction kinetics, and oxygen carrier reactivity while minimizing unburned carbon residues. Repeated cyclic operation indicates stable oxygen transfer performance and acceptable structural durability of the iron oxide particles during prolonged operation. Comparative assessment with conventional coal combustion technologies confirms substantial advantages in terms of reduced nitrogen oxide formation, lower carbon dioxide emissions, and simplified carbon capture requirements. In addition, the process demonstrates potential for improved thermal efficiency and sustainable fossil fuel utilization.