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For hydrogen to contribute effectively to a net-zero future, industries must minimize fugitive emissions during production, transportation, and usage.
The challenge of hydrogen leakage
Despite its environmental benefits, hydrogen leakage presents significant challenges. With a Global Warming Potential( GWP100) of approximately 12.8 ± 5.2,² hydrogen indirectly impacts climate dynamics by extending the atmospheric lifespan of methane, a potent greenhouse gas. Additionally, hydrogen leakage can contribute to tropospheric ozone formation and disrupt atmospheric energy balances, further impacting climate dynamics.
From a practical perspective, hydrogen leaks pose safety risks due to its unique properties. Its high flammability and extremely low ignition energy make it prone to combustion, while its nearly invisible flame in daylight complicates detection without UV / IR flame detectors or other specialized methods.
Hydrogen is also odorless and colorless, and because fuel cell applications require high purity, adding odorants for leak detection is
Sealing standards
The primary industry standards for testing sealing materials – such as ASME B16.20 and EN 13555( for gaskets), as well as API 622, API 624, API 641, and ISO 15848-1( for packing and valves) – typically use methane or helium as test gases rather than hydrogen. However, hydrogen behaves differently due to its smaller molecular size, higher diffusivity, and unique permeation properties. To account for these differences, leak rates from helium testing are often used as a reference, but helium does not perfectly replicate hydrogen’ s behavior. While helium’ s small size and inertness make it a convenient test medium, it does not fully capture hydrogen’ s permeation effects or material interactions. Direct hydrogen testing is essential for critical applications to ensure accurate leakage assessment and reliable sealing performance. challenging. This makes identifying leaks particularly difficult.
Sealing hydrogen effectively, therefore, requires advanced gasket and packing solutions that prevent leaks, resist degradation, and maintain integrity under varying conditions.
Electrolyzers and their sealing needs
Electrolyzers play a crucial role in green hydrogen production by splitting water into hydrogen and oxygen using electricity. There are two main types of electrolyzers:
• Alkaline electrolyzers( AEL): Use a liquid electrolyte, typically potassium hydroxide( KOH) or sodium hydroxide( NaOH). They are known for durability, cost-effectiveness, and scalability, making them well-suited for large-scale hydrogen production.
• Proton exchange membrane( PEM) electrolyzers: Utilize a solid polymer membrane, allowing for compact designs, high efficiency, and rapid response to fluctuating power inputs( such as renewable energy sources). However, they require precious metal catalysts( e. g., platinum, iridium), making them more expensive than AEL systems.
A critical component to ensuring efficiency in electrolyzers is the gasket. In an electrolyzer, cell frames separate individual cells, each housing an anode and a cathode. Positioned between each cell frame, gaskets prevent leaks, maintain system pressure, preserve the purity of the hydrogen produced, maintain electrical insulation, and ensure overall efficiency.
Identifying the optimal gasket materials and manufacturing techniques is essential for ensuring a dependable seal, minimizing risks, and maintaining compatibility with the operational conditions of electrolyzers.
Hydrogen Tech World | Issue 22 | June 2025 45