Chemical industry
Types of valves offered by Greene Tweed for hydrogen service . Image courtesy of Greene Tweed .
but a carbon capture and storage ( CCS ) technology is applied to capture the carbon dioxide emissions and store them underground . The long-term goal is to make green hydrogen from water via electrolysis using renewable electricity , ideally coming from wind or solar sources . However , fuel cell technology required to produce green hydrogen is costly , and today there is very limited infrastructure to produce or transport green or blue hydrogen required to create a sustainable hydrogen economy . Additionally , hydrogen is extremely flammable and explosive , making it difficult to store and transport . Due to a low energy density , its storage and transport require large volumes , high pressures , or cryogenic processes to be stored compactly in liquid form . Moreover , it can cause metals to become brittle , and very few pipelines are currently suitable to transport pure hydrogen . Hydrogen is one of the smallest molecules and can permeate almost every material , making it very difficult to seal . Debates continue , but recent announcements at COP27 and elsewhere make one thing clear : Hydrogen will play a major role in a clean , secure , and affordable energy future in the next few decades .
How Greene Tweed unlock hydrogen ’ s power
It is hardly surprising that hydrogen is catching everyone ’ s attention , from environmentalists and governments to boardrooms across the world . It is a very important piece of the Net Zero puzzle and investments in hydrogen production are set to exceed billions of dollars . 1 Yet , the majority of the equipment and processes needed to produce , store , and transport hydrogen are not ready to start working with it . Some of the biggest challenges presented by the tiniest , lightest molecule known to man include :
• High permeability of hydrogen can cause sealing issues and metal embrittlement .
• Hydrogen ’ s low lubricity can lead to wear and friction issues .
• Impurities in hydrogen can cause contamination of fuel cells .
• High impeller tip speed required to compress hydrogen with centrifugal compressors is barely achievable with metal .
Hydrogen benefits for valves
Valves are safety-critical components when producing or handling hazardous fluids . And hydrogen poses a few unique challenges . It is an extremely light and low-density gas . This means that it can penetrate any type of polymer or metal , causing leakage . “ Permeation is a huge problem with Hydrogen and that ’ s why it is critical to select products made of materials with minimal permeability to reduce leakage . For instance , cross-linking a material like PEEK could help to lower diffusion coefficient and enhance performance in hydrogen environment by reducing permeation ,” says Kerry Drake , Technology Manager at Greene Tweed . Arlon ® 3000XT crosslinked PEEK may therefore be an excellent solution for valve seats in Hydrogen service . Low lubricity of hydrogen molecules can generate valve seats wear and friction issues . For these non-lubricated environments , Greene Tweed offers WR ® 600 , a PFA composite with unique dryrunning properties , and Arlon ® 3000XT , the only cross-linked PEEK available in the market . When combined with high pressure , hydrogen permeation can generate Rapid Gas Decompression ( RGD ) issues . Greene Tweed recommends RGD-resistant Fusion ® 938 O-rings or MSE ® spring energized lip seals for extreme temperatures and pressures . Permeation issues can also occur at low temperatures , too , and Fusion ® 665 O-rings are best suited to overcome such problems .
www . valve-world . net Valve World March 2024 41