Pressure Swing Adsorption (PSA) - Hydrogen Purification

Pressure Swing Adsorption (PSA) from Air Liquide Engineering & Construction is used to recover and purify hydrogen from a variety of hydrogen-rich streams. The technology relies on differences in the adsorption properties of gases to separate them under pressure, and is an effective way of producing very pure hydrogen.

Automated processes

The feed gas for PSA can be raw hydrogen from a wide variety of sources, including steam methane reforming, partial oxidation, cryogenic purification, methanol plant purge gases, ethylene offgas, styrene offgas, gasification and ammonia plants.

During the PSA process, the hydrogen is recovered and purified at a pressure close to the feed pressure, while adsorbed impurities are removed by lowering the pressure. The PSA tail-gas, which contains the impurities, can then be sent back to the fuel system even without a tail-gas compressor. The entire process is automatic.

Air Liquide Engineering & Construction uses the most advanced adsorbents on the market with patented cycles that are optimized for recovery and productivity rates. The units are made for outdoor and unmanned operation, and are designed to be both compact and fully skid-mounted.

Advantages

• Produces hydrogen of up to 99.9999% purity
• On-stream factor is typically more than 99.9%
• Operates with a wide variety of feed gases
• Features patented cycles and advanced adsorbents
• Designed for unmanned, outdoor use
• Units are compact and skid-mounted

Key figures

• Capacity: 5 000 to 200 000 normal cubic meters per hour (Nm³/h)
• H₂ recovery rate: 60 to 90%
• Turndown: as low as 25%