Characteristics and kinetics of chemical looping combustion of Mn-doped Fe₂O₃ oxygen carrier with CO

Mn-doped Fe₂O₃ oxygen carriers with different molar ratios of Fe to Mn were prepared by co-precipitation method, which were characterized by XRD, BET and TEM. Chemical looping combustion tests between Mn-Fe₂O₃ and CO at different temperatures were performed to investigate the reaction characteristics, and to determine the optimized Mn doping amount and reaction temperature. The results reveal that a rational Mn doping could enhance the reactivity of iron-base oxygen carrier, and the optimal Fe/Mn molar ratio is 50. Multi-cycle experiments confirm the high stability of the optimized oxygen carrier. Furthermore, the reaction kinetic analysis at heating rates of 30, 40, 50 ℃/min shows that the Avrami-Erofeev model is suitable for the reactions, and the activation energy and pre-exponential factor can be calculated according to the kinetic model.