Sealing Hydrogen: Why It Is Hard and Which Materials Are Used

Hydro is a clean energy carrier that is invested heavily, but hydrogen sealing is one of the most difficult technical tasks of compressors and pipes.

The main challenges.

• The molecule is very small and lightweight so it is easily permeable through a variety of polymers and metals, causing leaks.
• Hydro can cause hydrogen embrittlement.
• Harsh working conditions: according to Freudenberg Sealing Technologies, the pressure can exceed 700 bars, the temperature from cryo to above 150 degrees C.
• Hydro is very flammable so leaking is both dangerous and cost-loss.

The solution is in the industry.

The companies have developed hydrogen-resistant elastomers and maintain resistance at extreme temperatures. With centrifugal compressors, API 617 limits materials in hydrogen environments to flow limits below 120 ksi or hardness below 34 HRC to avoid hydrogen fragility. Dry gas and gas-compatible magnets are used in hydrogen-rich compressors, and dry gas decompressors also help eliminate common oil pollution problems in piston compressors.

Meaning for the user.

• Select materials according to test data with hydrogen at actual pressure and temperature.
• Check for static and dynamic leakage in operating conditions.
• Work with experienced hydrogen suppliers.

Source of reference.

Gasworld (Freudenberg Sealing Technologies), Greene Tweed, Turbomachinery Magazine. Article compiled and reinterpreted by SNS-VN; brand name belongs to the owner.