Chemical looping combustion of coal with CuO-Fe mechanically mixed oxygen carrier

Chemical looping combustion has received great attention for its advantage to obtain pure CO2 at a manageable cost. Reaction of CuO and Fe2O3 mixed oxygen carrier (OC) with a Chinese lean coal was experimentally investigated by thermogravimetric (TGA) coupled with Fourier transform infrared spectroscopy (FTIR) and further thermodynamically simulated using HSC software. TGA-FTIR experiments indicated that the reaction of LPS with CuO and Fe2O3 mixed OC was more advantageous than that of LPS with CuO or Fe2O3 separately. And especially at the later reaction stage, high concentration of CO2 and H2O obtained from the reaction of LPS with CuO promoted LPS gasification and its further reaction with Fe2O3, and the maximum weight loss rate for the reaction of LPS with Fe2O3 was 0.326 wt%/min, far close to that of LPS with CuO at the initial reaction stage. Furthermore, thermodynamic simulation of the reaction of LPS with CuO and Fe2O3 mixed OC revealed that, in terms of LPS coal transformation, CO2 and H2O were the dominant products. Meanwhile, during the reaction of LPS with CuO and Fe2O3 mixed OC, CuO was mainly reduced to Cu, but besides Fe3O4, deep reduction of Fe2O3 into FeO occurred. Finally, CuO was preferred to react with FeS2 inherent in LPS to form Cu2S but the reduced Fe2O3 was easily reacted with SiO2 in LPS to form FeSiO3.