Considerations for a Hydrogen Plant in Canada: Design Factors That Cannot Be Overlooked

Alberta, Canada is on its way to becoming a significant hydrogen hub. As more hydrogen plants and pipelines are built in Canada, design considerations specific to hydrogen service will become increasingly important.

Good hydrogen plant design is necessary to ensure worker safety and equipment reliability. Here, we’ll look at some often overlooked hydrogen plant design considerations, like component and material selection, and why they are critical for any hydrogen plant design in Canada.

Properties of Hydrogen

Proper hydrogen plant design requires an understanding of hydrogen’s properties. By taking advantage of these properties, a facility can be designed to minimize hazards.

Hydrogen gas is non-toxic, non-poisonous, colorless, odorless, tasteless, and generally undetectable by human senses. While these properties mean it is usually not a safety concern, it makes leaks challenging to detect. Hydrogen is not harmful to humans directly, but it can create significant hazards under certain conditions.

Flammability

Hydrogen’s flammability range is vast compared to other gases, and the energy required for combustion is much lower. In other words, it only takes a tiny spark to ignite a hydrogen fire.

When it ignites, hydrogen burns with a nearly invisible pale blue flame that produces no smoke. In addition, hydrogen flames have low radiant heat, so you may not feel any heat unless you are very close to the flame. These characteristics can make it easy for hydrogen fires to go unnoticed without the aid of sensors such as thermal imaging cameras.

Buoyancy

Hydrogen is the lightest molecule in the universe, so it rises quickly when it leaks into the air. This can help mitigate the dangers of hydrogen leaks as the leaking hydrogen will not accumulate at the ground level where workers are. However, in enclosed spaces, it accumulates in-ceiling pockets, mixing with air and potentially creating an explosive mixture. Proper ventilation is essential to prevent this hazard. 

Embrittlement

Hydrogen is a tiny molecule that readily diffuses into many materials, especially under pressure. This can lead to reduced tensile strength, ductility, and increased fatigue crack propagation rate. This phenomenon is known as hydrogen embrittlement, and avoiding it requires careful selection of hydrogen-compatible materials for every component.

Hydrogen Plant Design Considerations

Hydrogen’s unique properties require unique design considerations. To reduce the risk of the hazards described above, follow these best practices:

Use Only Hydrogen-Compatible Materials

ASME B31.12 Standard on Hydrogen Piping and Pipelines provides material selection requirements and recommendations for hydrogen service. Austenitic stainless steels like 304 and 316 are recommended for all components in hydrogen service, and they should be used in the annealed condition if possible.

Some carbon steels can be used for gaseous hydrogen service if operating temperatures are at least -29°C. Still, they are not recommended for high-pressure applications, as they are more susceptible to embrittlement than stainless steel.

Aluminum alloys, copper, and copper alloys are also generally suitable for hydrogen service. However, nickel and nickel alloys are susceptible to severe hydrogen embrittlement and should never be used with hydrogen.

Prevent Leaks by Minimizing Joints

Because of its small molecular size, hydrogen leaks extremely easily. To limit potential leak points, piping and tubing should have the minimum number of joints possible. Where fittings are used, they must be suitable for hydrogen service and specific operating conditions. Welded fittings are preferred for piping systems as they have a lower potential for leaks than mechanical fittings.

Swagelok FK-series fittings are some of the only tube fittings engineered for the unique demands of hydrogen applications, with 316 stainless steel fabrication and pressure ratings up to 22,500 psi. In addition, SWS weld system are another valuable tool for hydrogen gas service in Alberta. These fixtures allow the welding of a gas-sealing connection that is an effective solution for hydrogen sealing.

Eliminate or Minimize Fire Hazards

To minimize the risk of a significant hydrogen gas release inside the plant, hydrogen gas should be supplied from an outdoor area at a safe distance from structures, ventilation intakes, and vehicle routes. When hydrogen is used indoors, it should be stored outdoors if possible and supplied to the indoor area using welded piping.

If hydrogen cylinders must be placed indoors, take the following precautions to prevent hazards:

• Limit the total hydrogen volume based on workspace size.
• Store hydrogen cylinders away from cylinders containing oxidants.
• Keep cylinders secured.
• Use only non-combustible materials for plant infrastructure.
• Set up ventilation systems to introduce air low to the floor and exhaust at the room’s highest point.
• Install hydrogen sensors throughout the plant.
• Install dispensers in unconfined areas with ceiling heights of at least 7.5 meters.

For High-Quality, Hydrogen-Compatible Components and Systems, Look to an Experienced Vendor

Edmonton Valve & Fitting offers a wide range of hydrogen-compatible Swagelok components with top-quality metallurgy, leak-tight designs, and high-pressure resistance. We also offer EC-79-certified components suitable for on-vehicle applications, heavy-duty, rail, ship, and aerospace.

Our Field Advisors can also perform an onsite consultation to assess your hydrogen plant’s needs and recommend the best systems and components to ensure safe, reliable operations. Field Advisory Services include, but are not limited to:

• Virtual onsite evaluations
• Design advice
• Leak detection and repair
• Product-specific training
• Component and instrumentation advice
• Regulator sizing guidance