HCR™ - High Claus Ratio
The process, developed and patented by Siirtec Nigi, is used to remove sulphur compounds present in tail gases from Claus plants thus meeting severe air pollution standards.
The HCR™ process consists of two sections:
- Hydrogenation and hydrolysis of sulphur compounds present in tail gases (COS, CS2, Sx and SO2). Tail gas is heated to about 300°C and, without hydrogen addition, is treated in Co/Mo catalyst. Gas passes through a waste heat boiler and is cooled down to approximately 40°C in a direct contact tower.
- H2S removal and recycle of acid gas to Claus plant. The gas is washed in a carefully designed amine absorber and the treated gas is incinerated. Rich amine is processed and recycled.Using the configuration of a Claus section followed by a tail gas section, the HCR™ process achieves an overall sulphur recovery of 99.9% or better. The process requires adjusting the operating criteria for the Claus unit by increasing the H2S/SO2 tail gas ratio. The operation is very steady and has high service factors that are achieved during upset conditions from upstream units. Hydrogen or reducing gas from external sources are not required in the hydrogenation reactor. Tail gas containing less than 250 ppmv of H2Sx can be sent to an incinerator.