Activity of Fe2O3 with a high index facet for bituminous coal chemical looping combustion: a theoretical and experimental study. Issue 88 (8th September 2016) - Qin, W.
Abstract : Iron-based oxide with high miller index facet Fe2 O3 (104) effectively promotes oxygen transfer at different oxidation states for oxidizing coal molecules into CO2 and H2 O during chemical looping combustion of solid fuel. Abstract : In this work, the reactivities of Fe2 O3 (104) and Fe2 O3 (001) at different oxidation states, as well as the regeneration properties, were comparatively studied theoretically and experimentally. Firstly, interactions between a bituminous coal model molecule and the perfect and reduced Fe2 O3 (104) and Fe2 O3 (001) surfaces under different temperatures were investigated by molecular dynamics. The results proved that the perfect and reduced Fe2 O3 (104) surfaces can effectively promote the adsorption of fuel molecules on the OC surface. Further, deep redox properties of Fe2 O3 (104) and Fe2 O3 (001) were studied by density functional theory calculations, which suggests that oxygen transport initiated from Fe2 O3 (104) occurs more easily than from Fe2 O3 (001), which will favor the combustion of coal. Moreover, Al2 O3 -supported Fe2 O3 (104) was synthesized via morphological-control to perform bituminous coal CLC experiments in a thermogravimetric analyzer (TGA). The comparison between reaction of Fe2 O3 (104)/Al2 O3 and bituminous coal and reaction of bituminous coal and the referenced Fe2 O3 /Al2 O3 which was prepared by the traditional impregnation method verified that the former shows a higher fuel conversion and less carbon residue. The regeneration of Fe2 O3 (104)/Al2 O3 was characterized by XRD and SEM. The high miller index surface iron oxide OC is shown to be efficient and rewarding for use in CLC of solid fuel.