Material test for P2X electrolysis plant

Challenge

For energy from renewable sources to provide a stable supply, it must be possible to store wind and solar energy. This can be done through power-to-X conversion, such as via electrolysis, where hydrogen is produced from water and electricity. Green Hydrogen Systems (GHS) manufactures and develops alkaline electrolysis plants. Alongside production, work is being done to optimise the electrolysis process, making it more efficient and competitive, so that it can be used to a greater extent for energy storage. Two important parameters in this development are increased operating temperatures and lower material costs. Unfortunately, elevated temperatures lead to increased material costs. There are many materials that are resistant to harsh environments (strong bases, high temperature and pressure, wear) in an electrolysis system.

Solution idea

In the manufacture of alkaline electrolysis systems, surfaces of either stainless steel or nickel are used — the latter either in the form of solid nickel components or (stainless) steel coated with nickel. The importance of nickel to corrosion protection depends on such factors as the concentration of lye, the temperature, and whether the component is located in the anodic or cathodic part of the lye circuit. Particularly critical are pipes, tanks, fittings, and other components on the hot part of the oxygen circuit. The safest solution from a design point of view is to use pure nickel.

The purpose of this project is to investigate the extent to which a defect in a nickel coating has an influence on the prevalence of corrosion in the steel as a function of alloy type. In other words, how quickly does lye penetrate various alloys if the coating is scratched, worn out, has a defect, or is otherwise damaged?

In the worst case, the penetration of lye can lead to drastic corrosion of the steel substrate and the components losing their mechanical strength. The ultimate result is that hot lye may be able to leak out of the system. This poses not only financial challenges, but also safety risks. Whether a higher alloy reduces the risk of penetration of lye over time is therefore an area of inquiry. The design life of the systems will typically be in the range of about 25 years. This will be investigated using accelerated tests at elevated temperatures. Any pitting that occurs under a damaged surface coating will also be examined. The goal is for the results of the project to enable the substitution of materials used in the manufacture of electrolysis components, ultimately lowering the price of a system. In addition, safety and mechanical integrity will be increased over the life of the system.

Problem solvers

• Green Hydrogen Systems A/S
• Chem-Tec Plating A/S
• Force Technology
• Energy Cluster Denmark