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Air Liquide
Cryocap™ H2 – Cryogenic CO2 Separation

Cryocap™ H2 – Cryogenic CO2 Separation

CO2 capture in hydrogen plants

Using its extensive experience in hydrogen plants, Air Liquide Engineering & Construction has developed a technology that captures the CO2 released during hydrogen production. Cryocap™­ H2 is the object of several patent applications and can deliver significant cost savings for clients. Furthermore, it is the only technique that reduces the amount of CO2 released during the production process while simultaneously increasing hydrogen production.

Condensation, distillation and pressurization

Used to capture CO2 in hydrogen production plants, Cryocap™ H2 involves compressing and drying offgas from the production process and sending it to a cryogenic unit. Partial condensation and distillation techniques are then applied to separate the CO2 from other components. As a result, a pure and pressurized CO2 flow is produced by the cold box.

Non-condensed gases are recycled through a membrane system to recover H2 and further CO2, and any residual gas is sent to burners in the reformer furnace. Finally, the resulting CO2 product is compressed to supercritical pressure or liquefied and stored in liquid storage.

Depending on customer requirements, an additional purification phase may be undertaken on a catalytic bed in order to burn remaining hydrocarbons and alcohols. Through this method, food-grade quality can be achieved.


  • Reduced CO2 emissions help improve environmental footprint
  • H2 production increased by up to 20%
  • The lowest cost of CO2 capture in hydrogen production plants (in particular compared to amines washing)
  • Adapted to both Greenfield and Brownfield H2 plants
  • Technology fully validated at industrial scale on a 50 000 Nm3/h H2 plant

Key figures

  • Capacity: 300 to 2 000 tons per day
  • H2 production: 10-20% increase

Cryocap H2