Properties of Cu-based Oxygen Carrier Used for Chemical Looping Oxygen Production

The optimal reaction temperatures were investigated via the temperature programmed thermogravimetry, and the effects of particle size, gas flow rate and reaction temperature on reduction and oxidation reactions were studied via isothermal thermogravimetry by using STA409PC thermal analyzer. BET, SEM and XRD were also used to analyze the specific surface area, surface morphology and phases of the prepared oxygen carriers. The results show that the Cu/Si oxygen carrier has the high reactivity of releasing and adsorbing oxygen when the temperatures are higher than 850 °C and 400 °C. The reaction rates have increased with gas flow rate increase and particle size decreasing, but the increase tendency is not apparent. The reaction rates increase greatly with the temperature increase. The oxygen carrier has excellent stability under 900 °C oxygen reduction and 700 °C oxygen oxidation conditions. Phases and surface morphology of oxygen carriers were measured by X-ray diffraction and scanning electron microscope before and after experiments. The main phases of oxygen carrier are composed of CuO and SiO2 in fresh and oxidized samples, Cu2O and SiO2 in reduced samples, which reveal that the oxygen carrier is stable when using the preparation process and under the operation conditions. The porous structure of cycled oxygen carrier is much more apparent than fresh samples and particles do not appear to disintegrate after 23 cycles.