Chuck Hayes, Global Technical Lead, Clean Energy, Swagelok

Constructing fluid systems to contain and harness hydrogen (H₂’s) potential is crucial as the world seeks cleaner energy and power options across multiple applications. Without the ability to handle, transport, store and dispense the gas safely and reliably, its ability to replace fossil fuels is diminished.

H₂-focused fluid systems require specialized knowledge of the gas and cannot be constructed using the same parameters as traditional oil and gas systems. The requirements and differences between the two types of systems are stark. Designers and engineers must take these requirements into account as they build systems to power the future of mobility and power.

What makes H₂ different. Unlike other fuel sources, H₂ presents particular challenges because of its status as the lightest element in the world. It consists of tiny atoms, a single positively charged proton and a negatively charged electron. Its small size means engineers and designers must be mindful of its ability to work into small crevices and escape. Ensuring a H₂ fluid system is leak-tight is far more challenging than a traditional oil and gas system. H₂ systems demand specific seals, materials and tubing connections.

Furthermore, H₂’s ability to get into small cracks and crevices leads to a specific type of corrosion called H₂ embrittlement, which can weaken metal’s ductility and its ability to resist fracture and fatigue under severe operating conditions. This can cause catastrophic failure of the system, putting employees at risk of injury, increased downtime and reduced profitability.

Unlike other fuels sources, H₂ requires high pressures to be stored safely (700 bar or about 10,000 psi in a common transportation application) and is subject to severe temperature differentials as it moves from one section of the system to another. This means the usual components used in oil and gas applications are insufficient to use in a H₂ fuel system because of the rapid pressure changes and temperature swings. Designers and engineers must use components specifically produced for H₂ fuel systems to ensure leak-tight operation and prevent H₂ embrittlement.

The need for specialized equipment extends beyond the production facility because consumers will eventually be dispensing it into their vehicles. Unlike the professionals behind the scenes, they will not have appropriate personal protective equipment, which makes designing the fuel pump extraordinarily important.

SYSTEM LEVEL COMPONENT CONSIDERATIONS FOR H₂

Several design considerations are crucial to making sure H₂-delivery systems are safe, reliable and efficient.

Fit-for-purpose materials. Generally, a well-designed H₂ system should be made from high-quality 316 stainless steel tubing materials, which have demonstrated good performance over lengthy service life.

Specifically, stainless steels containing elevated levels of nickel can deliver optimal performance in H₂ systems. The American Society for Testing and Materials (ASTM) requires a minimum of 10% nickel in 316 stainless steel formulations, but 316 stainless steel with a minimum of 12% nickel is better for the unique challenges posed by H₂. Nickel content helps stabilize the microstructure of stainless steel, enabling it to be more resistant to H₂ embrittlement.

Elegant design. Because H₂ can more easily leak through small crevices than other gaseous materials, it can be advantageous to design your H₂ systems with as few leak points as possible. This means minimizing the number of individual connections throughout the system, using proper tube bending techniques in strategic locations rather than implementing another fitting. A reliable supplier may be able to assist you with design training opportunities.

With H₂ becoming a more common alternative to traditional fossil fuels, designers and engineers must adapt to the unusual needs of H₂ fluid systems. The success of such efforts will play an essential role in determining whether H₂ will ever become widely adopted as a long-term, sustainable fuel solution. Finding a supplier dedicated to helping clean energy professionals achieve these goals will go a long way to ensuring the system will be built with the right components, services, and support.

About the author

CHUCK HAYES is a 32-year veteran of Swagelok Company, a world leader in the development of fluid system products, assemblies, and services. He has spent the last 25 years developing a wide range of fluid system products and the past 20 years focused exclusively on fitting technology for alternative fuel applications. Chuck currently holds seven patents in the U.S. and numerous patents internationally.