Selective Catalytic Oxidation Of H <sub> 2 </ Sub> S A Catalyst For Development,

The method of selective oxidation of H2S to sulfur has been extensively used in directly removing sulfur from low concentration (less than 15 vol.% ) acid gas. Multi-metallic oxide catalysts prepared by a co-precipitation method were used for the reaction of selective oxidation of H2S to sulfur. Firstly we studied the conversion and selectivity of H2S to stolfur of the singular metallic oxides, then several kinds of multi-metallic oxide catalysts were prepared by the co-precipitation method and studied thek catalytic activity and selectivity. Afterwards the composition and synthesis conditions were decided. The physical properties and characterization of catalysts were conducted. Some conditional experiments were also performed.Under the experimental conditions: catalyst load 1.0 ml of size 20-30mesh, O2/H2S ratio 0.5, temperature 180-260℃, the conversion and selectivity of the catalytic reaction both reached over 90%. The influence of granularity of catalysts, precipitation temperature and calcining temperature of synthesis were performed in order to decide the conditions of synthesis. The influence of space velocity, O2/H2S ratio and etc. were also performed. The results showed the space velocity at the range of 2500~4000h-1 had little influence and optimum of O2/H2S ratio was 0.5. The 40 hours lifespan test of the synthesized catalyst was conducted and the conversion and selectivity were maintained about 95% and 93% respectively.The physical properties of the synthesized catalyst were as following: average density 1.46g/ml, specific surface area 188.6m2/g, axial crushing strength 3.54*106~ 8.92x106N/m2, radical crushing strength 8.93~17.86N/cm. The characterization of X-ray diffraction (XRD) and SEM indicated that the bulk structure of the fresh catalysts was amorphous in general and the structure of used catalysts changed apparently. There were crystal compounds of metallic sulfides and element sulfur in the used catalysts. The performance of metallic sulfides showed ZnS and FeS2 had certain catalytic conversion and selectivity. It indicated that the catalysts still could maintain good performance although some metallic oxides converted to sulfide gradually during the reaction.