Sabine Savin-Poncet

Direct oxidation of H2S into S. New catalysts and processes based on SiC support

Abstract Nickel sulphide, supported on SiC, exhibits a very high activity and selectivity for the direct oxidation of H 2 S into S at medium temperatures (100–120°C) or at room temperature (20–40°C). Iron oxide, also supported on SiC, is highly reactive, and selective, for the same reaction at higher temperatures (210–240°C). This support is very stable, insensitive to steam and to any sulphur compounds in this range of temperature.

Selective oxidation of H2S in Claus tail-gas over SiC supported NiS2 catalyst

Very high activity and selectivity could be achieved for the direct oxidation of H 2 S into elemental sulfur at low reaction temperature (40-60°C), on nickel sulfide supported SiC catalyst. The heterogeneous nature of the support surface (hydrophilic and hydrophobic areas) could explain the important role played by water to maintain a high and stable H 2 S conversion level. The formation of a very active superficial nickel oxysulfide phase was proposed in order to explain the activation period necessary at reaction temperatures <60°C. Total selectivity for sulfur was attributed to the very low reaction temperature and the absence of any microporosity in the support.

Silicon carbide supported NiS2 catalyst for the selective oxidation of H2S in Claus tail-gas

The selective oxidation of H 2 S into elemental S, in a discontinuous mode (100°C), is reported. A very efficient (100% yield) nickel sulfide catalyst supported on a new type of support, silicon carbide is used. This support avoids reactions with the support during the test or the regeneration cycles, due to its chemical inertness.