V2O5/TiO2 acting as both oxygen carrier and catalyst for chemical looping oxidation of H2S at a low temperature

Chemical looping oxidization of H2S at a low reaction temperature was investigated. A V2O5/TiO2 oxygen carrier produced by sol-gel method was employed, and experiments were performed in a fixed bed. Effects of reaction temperature (150-250 degrees C), H2S inlet concentration (1000-4000 ppm) and cycles on H2S conversion behavior were investigated. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the oxygen carrier property. Finally, the S conversion pattern and role of oxygen carrier during the proposed chemical looping route were identified. Thermodynamic analysis and experimental results confirmed the proposed elementary sulfur production during reduction stage and a significant SO2 production during oxidization stage. Experimental results confirmed the proposed elementary sulfur production during reduction stage and a significant SO2 production during oxidization stage. At 150 degrees C, the selectivity of SO2 during reduction stage is less than 5%, and the fraction of the converted H2S to S is higher than 95% in the present condition. XRD and XPS results supported that V5+(V2O5) was reduced to V4+(VO2) by the continuous feeding H2S. During oxidization stage, the V2O5/TiO2 material acted as both oxygen carrier and catalyst to produce SO2 for further H2SO4 production.