Metal-oxide stabilized CaO/CuO composites for the integrated Ca/Cu looping process

An integrated Ca/Cu looping process has been proposed recently for CO2 capture. It uses the exothermic in-situ reduction of CuO with methane or natural gas to supply heat required endothermic calcination CaCO3 regenerate CaO following sorption cycle via bifunctional CaO/CuO composites. composites possess excellent redox characteristics, but rapid decline in capture performance remains an unresolved problem. Two different types stabilizers, i.e., Al2O3 that can form a mixed phase CaO, and MgO does not under reaction conditions, were incorporated into Pechini method, investigated by thermogravimetry. The results showed incorporation enhanced cyclic stability significantly, formation calcium-aluminum oxides improved more than did MgO. best performing Al2O3- MgO-stabilized exhibited uptake 0.14 0.09 gCO2/gmaterial after ten repeated cycles, exceeding unstabilized 100% 29%, respectively. We observed 15 mol. % is optimal quantity Al2O3-stabilized composites, ensuring high cyclically stable capacity (0.11 45 cycles). Moreover, was remarkably increasing carbonation/oxidation temperature (from 550 750 °C). In-situ X-ray powder diffraction suggest intermediate Cu2O played important role at temperatures.