Abstract �In the conventional chemical looping combustion coupling process, fuels are oxidized by metal oxides to generate pure CO2 stream for sequestration after steam is condensed while the metal oxide is reduced to metal. In order to improve the process kinetics, a concept called chemical looping combustion uncoupling has been put forward. In this uncoupling process, specific metal oxides are selected to directly release free oxygen for the combustion of fuels while the metal oxide is reduced to a lower oxidation state, instead of metal. The free oxygen oxidizes the fuel similar to the conventional oxy-fuel combustion. The major oxygen releasing metal oxides are copper oxide (CuO) and manganese oxide (Mn2O3). In this study, copper (II) oxide (CuO) on Al2O3 support oxygen carrier, was investigated in view of its oxygen releasing properties and thermal stability. Results indicated the Al2O3 support significantly impacts the oxygen releasing performance and thermal stability of the CuO on Al2O3 oxygen carrier, comparing with the commercial CuO powder. The kinetics of the O2 release from CuO decomposing to copper (I) oxide (Cu2O) was slow and temperature-dependent. However, there was no serious agglomeration of CuO on Al2O3 oxygen carriers. This contrasted the severe agglomeration of commercial CuO powder. The quick formation of a new crystal phase (CuAl2O4) cross-linking CuO and ?-Al2O3 may be the major reason contributing to both the stability of copper-based oxygen carrier under severe uncoupling condition (close to melting point of copper), and slow kinetics of O2 release. It was also found the reactor material was highly active, such as iron in the regular stainless steel, and likely consumed the released oxygen. This could be largely minimized when the reactor was made of quartz material.

Comparison of chemical looping combustion coupling with uncoupling

245th National Meeting (2013)

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