Detailed Program of the 22nd ISC 2024

Static Seals for Sealing Hydrogen: A Review

Summary

Hydrogen has a potentially large role in the future of energy, either as a fuel, as an energy storage vehicle, or both. Based on the amount of research work and government funding in this area, such as the US Government’s pledge of $7 billion for hydrogen hubs, it would be a good assumption that the role of hydrogen is set to grow for the foreseeable future. This is especially the case for so called green hydrogen, where hydrogen is produced by the electrolysis of water and the electricity used in the electrolysis is from a renewable energy source (e.g., wind, solar).

Due to its inherent properties, there has been some concern about the potential for leak-age of hydrogen in this new process industry. This, of course, brings into focus the sealing of static bolted connections, i.e., bolted flange joints. The most common leakage tests for bolted flange connections use either helium (EN13555), methane (ASME B16.20) or nitrogen (DIN 3535), but not hydrogen. There are good reasons for choosing these gasses, particularly helium, which is safe and a small molecule which can be detected and measured by standard equipment such as a mass spectrometer.

Other literature has shown that leak rate of different gases cannot be judged and predicted by molecule size alone, therefore the conversion of leak rate using a standard test and test gas cannot be easily converted to a leak rate of hydrogen. Therefore, testing of gaskets with hydrogen has been required to make engineering decisions.

This paper will review recent public domain papers on sealing tests using hydrogen, especially those comparing hydrogen sealing rates to helium sealing rates. This paper will also include some recent hydrogen sealing testing commissioned at a third party test house using spiral wound gaskets with different fillers.