The CANSOLV TGT+ system for ultra-high sulphur recovery is based on Shell Cansolv’s sulphur dioxide (SO2) scrubbing process. The system helps to achieve the most stringent emission standards mandated in different jurisdictions, including those mandated by the World Bank (SO2 stack emission <150 mg/Nm3), at competitive capital and operating costs while minimizing process line-up complexity.
For ultra-high levels of sulphur recovery, the Cansolv TGT+ sour gas treating system can serve as a destination for all the plant’s sour gas streams, including:
- flash gases from the acid gas removal unit (AGRU)
- treated residue gas from the acid gas enrichment unit (AGEU)
- tail gas from the Claus sulphur recovery unit (SRU)
- sulphur degasser off-gas
- sour water stripper off-gas
- disulphide oils generated in caustic treating of extracted natural gas liquids (NGL) or condensate
CANSOLV TGT + (Tail Gas Treating Plus) Benefits
- Destination for all sour gas contaminants streams in a plant
- Simplified process line-up – Lower number of process units
- Ultra-high sulphur recovery efficiency – up to 99.99+%
- Centralized treating of all sulphur-containing process off-gases
- Access to World Bank standards associated capital
- Reduce or Eliminate transportation (reagent/waste) and landfill obligations
- Manage multiple sour streams in one system
The key process steps are:
- SRU tail gas and other sulphur-containing gas streams are directed to a thermal oxidiser where all the sulphur compounds are converted to SO2.
- The incinerated gas is cleaned and cooled in a wash tower before entering the Cansolv SO2 absorber, where SO2 is selectively removed.
- The Cansolv solvent is highly selective to SO2.
- No other compounds in the gas are absorbed: they are discharged directly to atmosphere through the stack.
- The SO2-containing solvent leaves the absorber and is regenerated using steam to produce a concentrated SO2 stream that can be accommodated by the SRU.
- The captured SO2 is recycled as a pure stream to the SRU reaction furnace, where it reacts with incoming H2S in the acid gas to form elemental sulphur.