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  • Oil Refining
  • Petrochemicals
  • Gases
  • Alternative Fuels
  • Water


SPREX® is a process developed for bulk acid gas removal from highly sour gas. SPREX® offers economic alternatives for the development of highly sour gas reserves with acid gas reinjection which allows CAPEX and energy consumption reduction and limits sulfur production. SPREX® has been developed to meet the challenges of the development of very sour (>10% acid gases) natural gases.

Process Principle

Highly sour gases are splitted in a cryogenic distillation, producing partially sweetened gas at the overhead and liquid acid gas mixture at the bottom, which is suitable for reinjection.

Process Scheme


  • H2S bulk removal from raw gas with over 25% H2S, with reinjection of liquid H2S
  • No upstream sour gas dehydration needed

Key Benefits

  • Bulk H2S or CO2 removal from highly sour gas by high pressure cryogenic distillation
  • Conventional distillation column with no hydrate or solid product formation
  • Separated acid gases are recovered liquid at high pressure and easily pumped back into reservoir
  • Final sweetening of partially treated gas may be done with a conventional amine unit
  • Economic alternatives for the development of highly sour gas reserves with acid gas reinjection
    • Reduced capital cost and energy consumption versus conventional alternatives
    • Limits sulfur production and/or CO2 release to atmosphere
  • Proprietary solid/liquid/vapor thermodynamic model, validated through lab data and demonstration plant operation
  • Process design and robustness of operation validated through demonstration plant operation for more than 18 months


SPREX® is a joint development between IFP Energies nouvelles, TOTAL and Axens Solutions.

Associated Offer

Catalysts & Adsorbents



Axens Horizon
Axens Horizon
Operations Support

Modular Offer & Equipment