«We are currently working on identifying the best materials but do not want to rely purely on theory and literature.»
Raffaella Villa, Business Development Engineer, MCM S.p.A, Italy
Environment and climate protection policies are pushing for ever more decarbonisation. Hydrogen is a highly promising source of energy for the future. Its calorific value is greater than oil or natural gas and it combusts with neutral impact on the climate – that is, without releasing CO2. Hydrogen is known as “green” hydrogen when it is produced from renewable sources. Costs are going down but are still relatively high – for the time being ... Nowadays, hydrogen is generally blended with methane or natural gas to reduce the CO2 footprint.
The unstoppable advance of hydrogen
“Investment in hydrogen technology is massive right now,” remarks Raffaella Villa, Business Development Engineer at MCM S.p.A in Italy. The company is part of the Angst+Pfister Group and specialises in rubber seals for the automotive, aerospace and oil industries. Enquires about hydrogen seals at MCM have increased dramatically since 2020. “We are expecting even more in the near future.” This is in part due to the fact that hydrogen can be transported along the existing global pipeline network. No new infrastructure is required. It’s a mere matter of repurposing.
“We are already working on hydrogen applications and, within this ambit, a very interesting and significant collaboration is the one with Starline SpA: it is about valves used for the production of green hydrogen, where service in 97% vol hydrogen is required.” Starline SpA, forged steel ball valves maker, is a hydrogen pipeline valve manufacturer. Those valves now require seals suitable for hydrogen. The valves will be supplied to companies such as Iberdrola – a Spanish energy giant among the European electricity producers and distributors. Iberdrola is investing untold billions in the production of green hydrogen.
What is the optimum seal material?
“Gas is a tricky one for elastomer seals, especially hydrogen,” says Raffaella Villa. There are completely different requirements to be met than for liquids – in addition, hydrogen is the smallest molecule of all. This gas can slowly diffuse through the molecular structure of polymers. That’s why the focus is on the permeability of elastomer compounds. Escaping hydrogen is a serious safety concern. High pressure in the pipelines makes hard elastomers the most likely choice. However, not all compounds behave in the same way with hydrogen.
“We are currently working on identifying the best materials but do not want to rely purely on theory and literature,” says Raffaella Villa. FKM and HNBR have already been floated as potential solutions for hydrogen, but MCM also wanted to investigate precisely which elastomer is most suitable for which function. “We want to produce a ranking system.” For this reason MCM is having its entire portfolio permeability tested by an external laboratory.
Reliable permeability data
Although hydrogen itself does not damage elastomers chemically, environmental conditions can be an issue. In general, this means: the higher the pressure or temperature the more permeable the seals become. Depending on the intended application, chemical resistance can also be a requirement. All these factors limit the choice of elastomer – and usually a compromise is sought. MCM aims to present its customers with reliable data on applications involving hydrogen.
The current project for Starline required exceptionally hard seals that can withstand pressure to 35 bar – but also modest temperatures from minus 10 to 65 degrees Celsius. “Starline could use one of the compounds in our portfolio to develop valves for its Iberdrola project, but we are now checking what our portfolio can further deliver. The portfolio is already enormous but we would nonetheless be prepared to develop new elastomer compounds for hydrogen seals,” explains Raffaella Villa. At the end of the day, they would also be of interest to other industries such as the automotive industry.
Experience and expertise for new applications
Reliable data and choice of material are one thing – MCM is also contributing its expertise in compression and injection molding of the parts. “The moulds for such materials are not a trivial matter,” adds Oliviero Mismetti, who is Project Manager at MCM. MCM’s experience is crucial for the required tolerances in manufacture. MCM’s knowledge is also in demand for AED (Anti-Explosive Decompression) approvals – that is, for decompression resistant seals. “It is exciting that, thanks to our capabilities, we are asked to produce pioneering work on new technologies that will force decarbonisation in Europe,” Raffaella Villa is delighted to report.st to other industries such as the automotive industry.
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published: 10 Mar 2022 07:37:00 by: Angst+Pfister Magazin2022