A combined absorption catalytic conversion process for complete COS destruction developed by IFP Energies nouvelles. By combining amine absorption with catalytic COS hydrolysis, COSWEET™ allows gas sweetening, either total (removal of both H₂S & CO₂) or selective (removal of H₂S mainly), with complete COS removal. COSWEET™ is applicable with any type of absorption solvent.

Process Principle

  • Removing the bulk of the H₂S and CO₂ present in the feed gas by absorption in the bottom section of a solvent absorber.
  • Withdrawing the partially sweetened gas from bottom section of the absorber, water washing, heating to mild temperature and sending it to a hydrolysis reactor, where COS is converted to H₂S and CO₂.
  • Cooling the hydrolyzed gas and removing the H₂S (and if needed also the CO₂) by absorption in the top part of the amine absorber, down to the required specification

Process Scheme


Key Benefits

  • COS destruction integrated with amine sweetening
  • Very active catalyst destroys COS down to the ppm level at moderate temperature
  • Low pressure drop and moderate energy consumption
  • Used with any amine solution
    • With MDEAmax: complete COS removal
    • No impact on H2S /  CO2 selectivity
    • No impact on Sulphur Recovery Units
    • With HiLoadDEA / energizedMDEA: COS destruction boosted at reduced cost
  • Economics:
    • CAPEX: -15%
    • OPEX: -20%
      Compared with alternative COS removal options

A process developed by IFP Energies nouvelles