Janne Halonen, Toimitusjohtaja, West Welding Oy
Hydrogen is an ideal fuel from a climate perspective. It is non-toxic and easy to produce using renewable energy sources such as solar and wind power. Additionally, burning hydrogen is environmentally friendly, as it only produces water vapor as a byproduct of combustion. The potential of hydrogen is promising, but at the same time, its storage and handling pose challenges that are important to understand and address.
Hydrogen Embrittlement Weakens the Properties of Metals
Hydrogen embrittlement refers to the reaction caused by hydrogen which weakens the properties of metals. Hydrogen embrittlement is not a new phenomenon and has been studied extensively. It occurs in process industries wherever hydrogen is involved.
All metals that come into contact with hydrogen are at risk of hydrogen embrittlement. Hydrogen embrittlement occurs when small hydrogen atoms penetrate the crystal structure of the metal. This, in turn, weakens the material’s properties and leads to embrittlement and cracking.
“In hydrogen pressure equipment where the effects of hydrogen embrittlement haven’t been properly considered in the design and manufacturing, hydrogen embrittlement can occur shortly after the equipment is put into use,” warns Janne Halonen, the CEO of West Welding.
“If significant repairs are required to be made to the equipment just a few years after its commissioning, it can mean a substantial financial burden, as repairing a damaged device may not be cost-effective,” Halonen cautions.
“Typically, the expected lifespan of pressure equipment is at least 25 years, but well-manufactured and maintained pressure equipment can last over 50 years,” Halonen continues.
For this reason, it is crucial to consider the specific requirements imposed by hydrogen when designing hydrogen pressure equipment.
Design and manufacture of hydrogen equipment differ from standard pressure equipment due to the unique behavior of hydrogen with metals. This aspect must be recognized and accounted for by the equipment manufacturer.
The Importance of Welding Knowledge in Risk Mitigation
West Welding has extensive experience and strong expertise in the design and manufacture of demanding pressure equipment.
“We have manufactured pressure equipment for various demanding conditions and, as a result, developed welding processes suitable for them. In demanding processes, the importance of using the right welding method becomes even more pronounced. For equipment involving hydrogen, welding quality is of paramount importance. Welding must follow parameters validated by welding procedure tests and guidelines developed based on these tests,” Halonen reminds.
“In simple terms, ‘soft’ welds and ‘soft’ materials are more favorable in terms of hydrogen embrittlement,” Halonen explains.
“A hard weld increases the risk of hydrogen-induced embrittlement. Therefore, weld joints must be soft and flawless. Certain welding processes, such as submerged arc welding, are better suited for hydrogen pressure vessels than others,” Halonen specifies.
With Hydrogen Equipment Sizing Matters
In high-strength materials, hydrogen embrittlement can progress particularly quickly. Therefore, when designing and manufacturing equipment, efforts are made to select softer materials that can better withstand the effects of hydrogen.
“These include low-strength steels, such as P265GH or P275NH carbon steels,” Janne Halonen explains.
When manufacturing pressure equipment, strength calculations or sizing are always performed. At West Welding, all pressure equipment is designed from scratch, and when designing vessels and equipment related to hydrogen, both standard sizing and experience-based sizing are used.
“Our extensive experience in designing demanding pressure equipment has shown that standard sizing may not be sufficient, and it’s worth adding a margin of safety to the sizing,” reveals Janne Halonen.
“This ensures that the risks posed by hydrogen are also minimized in terms of sizing. While costs may increase slightly, this enhances the equipment’s lifespan, durability, and safety, ultimately paying for itself,” Halonen promises.
Storing Hydrogen Has its Challenges
Hydrogen has low density, so storing large quantities of hydrogen must be done either at high pressure or as a cryogenic liquid at extremely low temperatures. High-pressure storage requires heavy pressure vessels with thick walls.
Liquefying hydrogen is an option, in which case hydrogen must be cooled to -253°C, close to absolute zero. Storing such cold liquids presents its own challenges, requiring specialized expertise and cryogenic pressure vessels.
“However, in my opinion, we should aim to reduce the need for hydrogen’s long-term storage. Short-term storage is easier and safer,” Janne Halonen continues.
While hydrogen storage presents many challenges, they can be overcome with the right expertise, careful design, and high-quality manufacturing.
“We believe that with the right solutions, we can efficiently and safely harness the potential of hydrogen,” CEO Janne Halonen concludes.
