Coal gases contain mainly CO, H2, CO2, moisture, H2S, and other contaminants. Hydrogen sulfide in coal gases is required to be removed prior to utilizing coal gases for various purposes such as power generation and hydrogen production.
Monolithic catalysts for the development of a single-step sulfur recovery process are used to remove H2S from coal gases in this study. Sulfur dioxide is used as an oxidizer to convert H2S into liquid element sulfur. Monolithic catalysts, wash-coated with gamma alumina oxide, are impregnated with various metal promoters to increase removal of H2S from coal gases and decrease formation of COS. H2S in coal gases is reacted with SO2 to remove H2S from coal gases. This heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam on active sites of catalysts. Some of produced liquid elemental sulfur is attached to porous structure of catalysts, and poison catalysts. Deactivated catalysts are regenerated by removing liquid elemental sulfur with nitrogen at elevated temperatures.
Effects of catalyst age on conversion of H2S to elemental sulfur and formation of COS and various regeneration methods of catalysts poisoned with liquid elemental sulfur are described in this presentation. Performances of regenerated catalysts are presented in terms of H2S removal capacity and selectivity of COS at various reactor operation conditions.