Reactivity of a Chinese lean iron ore as oxygen carrier: Kinetics and characterization

Chemical looping combustion is a promising technology for the CO2 capture in the fossil fuel combustion without extra energy penalty. As the medium transferring the oxygen from the air to the fuel, oxygen carrier plays a significant role. This work focused on the kinetic parameters and the microstructure changes of a cost-efficient lean iron ore as the oxygen carrier reduced with 15% methane. Different kinetic models were employed to fit the reduction kinetics of the oxygen carrier, among which a two-step controlled one was suitable for the methane reduction process. The apparent activation energies of this oxygen carrier were 157.5kJ/mol and 126.9 kJ/mol in these two parallel reactions. The SEM characterization of the oxygen carriers demonstrated the sinter of the oxygen carrier became severe with the increase of the reaction temperature, which resulted in the reactivity deterioration at high temperature.