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The 2024 Valve World show held in Dusseldorf, Germany, was a top draw for those involved in the deployment of hydrogen in the energy transition. This article sums up some of the key findings of several conference presentations addressing this smallest of molecules.
By KCI Editorial
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Fugitive emissions testing
Valve tightness is of course both an environmental and a safety concern for systems containing hydrogen, explained Cetim’ s Mr Sauger. He continued by stating that existing tightness tests and designs based on helium or methane may not be conservative for hydrogen process fluid. At the same time, many existing installations and equipment in gas transmission systems dedicated to natural gas may move to hydrogen and / or hydrogen and methane blends with an impact identified on seals. This means there is a need for validation of sealing performance for new or repurposed installations at material / sealing system & equipment levels. His presentation then continued with several sections which discussed the following: the development of a fugitive emissions test installation with hydrogen; a fugitive emissions procedure for valve testing; test results on a ball valve; stem seal testing on a hydrogen test bench. He further explained that the test installation used a 4” class 600 ball valve with an Atex IIC actuator. Giving specifics, he noted that the stem seal comprised elastomer O-rings( FKM), there was an internal metal seal, and the flanges were fitted with graphite spiral wound gaskets. Finally, leak rates were measured using the vacuum test method. In conclusion, Mr Sauger noted that Cetim has developed a safety approach to performing hydrogen tests, with facilities to measure fugitive emissions of hydrogen at high and sub-zero temperatures. Further, following a test program carried out with FKM and HNBR seals( following ISO DIS 12101), low interfacial leakage was seen at – 20 ° C. However, hydrogen
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Photo: Messe Düsseldorf / ctillmann |
permeation through elastomers could be observed at 60 ° C.
Polymeric materials
Hydrogen effects on polymeric materials: permeation, rapid gas decompression and ageing tests was the title of a presentation delivered by Ms Simona Macchi from Effeciemme Componenti. The need to conduct research into this area was clear from one of Ms Macchi’ s first slides: as hydrogen is highly combustible, materials need to be selected that are not affected by gas permeation and leakage. She further outlined that tests had been performed with 100 per cent hydrogen, such as permeation in accordance with ASTM D1434 / ISO 2782-1, rapid gas decompression in accordance with API 17J / ISO 13628-2, and ageing in accordance with Effeciemme Standard( includes soaking in hydrogen for 36 days). Her presentation went into quite some depth. Hence the term permeation was characterised as the product of two additional factors, namely diffusion( reflects the penetrant mobility in the polymer) and solubility( reflects the affinity of the gas for the polymer). Further, permeation depends on factors such as temperature, pressure, the molecule size and interaction, the thickness and surface area of the polmer and also the polymer type and filler. Jumping to some of the findings, Ms Macchi noted that following permeation tests, rapid gas decompression tests and also ageing tests, no issues were observed with PTFE and PEEK-based materials. And, giving an insight into possible future areas of research, she indicated a next step could include ageing tests in accordance with NORSOK M710( ISO 23936-1).
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