Reactivity and stability of Cu-decorated Fe₂O₃/Al₂O₃ oxygen carrier for chemical looping combustion

The Fe₂O₃/Al₂O₃ oxygen carrier decorated with 10% Cu was prepared by freezing granulation method; its reactivity and stability for chemical looping combustion was investigated in a thermogravimetric analyzer by alternately exposing the oxygen carrier to reducing and oxidizing conditions to simulate the chemical looping combustion (CLC) process. The results indicated that the Cu-decorated Fe₂O₃/Al₂O₃ oxygen carrier exhibits a good stability during the isothermal redox cycles at 850 and 900 ℃. Although the oxygen carrier is sintered slightly at the beginning of redox cycles at 950 ℃, it is stable in the later cycles. With the increase of the reaction temperature, the oxidation rate of the oxygen carrier increases monotonously, while the oxygen transport capacity and reduction rate decrease first and then increase along with the temperature. Compared with the non-decorated Fe₂O₃/Al₂O₃ oxygen carrier, the Cu-decorated Fe₂O₃/Al₂O₃ oxygen carrier exhibits higher oxygen transport capacity and reduction rate, but lower oxidation rate at 900 ℃; both of them has a good stability during the redox cycles.