In the gasification unit, a carbon-containing material such as biomass reacts with a controlled amount of oxygen and steam at high temperature. Sour shift, or sulfur-tolerant shift, is analogous to the water-gas shift reaction and is implemented in gasification-based processes to enrich the hydrogen content of syngas. This process is used in hydrogen, ammonia, methanol, RNG and IGCC power plants around the world.
Depending on the desired carbon monoxide conversion, the sour shift process can be carried out in either one or several steps. Multiple reactors, typically with cooling between each bed, are required for high carbon monoxide conversion due to the equilibrium characteristics of the sour shift reaction.
The high performance of Topsoe’s sour shift guard material (GSSK) and catalyst (SSK-10) is well-proven under all operating conditions, and SSK series catalysts have consequently been installed in some of the world’s largest sour shift installations.