Mechanically Stable Mixed Metal Oxide of Cu and Mn as Oxygen Carrier for Chemical Looping Syngas Combustion

Chemical looping combustion possesses an inherent advantage of separation of CO2 from the carbon based fuels including thermal power plants that would offer effective mitigation of CO2 emissions through carbon capture and sequestration. In this study, a stable and regenerative mixed transition metal oxide of Cu and Mn (CuMn2O4) is synthesized through coprecipitation method and tested for multicycle performance for the oxidation of syngas as fuel. It was observed that 90% of the oxygen carrying capacity of CuMn2O4 can be utilized for the oxidation of syngas with almost 100% conversion efficiency in a packed bed reactor. The conversion efficiency of both CO and H2 was not altered significantly in all the tested cycles. CO2 and H2O were the sole products of syngas conversion. The phase of CuMn2O4 can be regenerated solely by aerial oxidation of the reduced products (Cu and MnO) at 800 °C. Utilization of maximum oxygen carrying capacity can reduce the circulation frequency of oxygen carrier between air and fuel fluidized bed reactors that can reduce the energy penalty significantly. The pelletized oxygen carrier possess appreciable mechanical strength that showed microhardness up to 2186 N/mm2 which is suitable for fluidized bed CLC reactors.