Learn how to select the perfect valves - from material compatibility to leakage prevention. Important tips for your hydrogen project!
Uncover the ins and outs of selecting the perfect valve for hydrogen projects, taking into account material compatibility, leakage prevention, and application requirements.
As a clean and sustainable energy carrier, hydrogen has the potential to play a pivotal role in the global energy transition, contributing to the reduction of greenhouse gas emissions and our reliance on fossil fuels. In the Power-to-X framework, hydrogen serves as the foundation for the production of:
various synthetic fuels,
chemicals,
and materials, such as ammonia, methanol, and synthetic natural gas.
These products can be used across multiple sectors, including transportation, industry, and heating, offering a wide range of applications and opportunities for decarbonization. At present, the Earth's temperature has increased by approximately 1.1°C compared to the late 19th century, and emissions are still on the rise. In accordance with the Paris Agreement's goal to limit global warming to a maximum of 1.5°C, it is essential to decrease emissions by 45% by 2030 and achieve net-zero emissions by 2050.
Material compatibility
Choosing the appropriate valve for hydrogen applications starts with comprehending the importance of valve materials and manufacturing processes. It is crucial to select a hydrogen-compatible body material to prevent complications such as metal embrittlement, heightened pressure, and internal stress. “Austenitic steel types, like 316/316L, are endorsed for this purpose, as they fulfill these criteria and have been acknowledged in the VDMA (German Engineering Federation) positioning paper,” says Marcel Gossmann, Business Development Manager at KLINGER Schöneberg.
“Besides the body material, it is essential to ensure that non-metallic components, including sealing materials and lubricants, are also hydrogen-compatible.”
Marcel Gossmann is Business Development Manager at KLINGER Schöneberg
This guarantees durability, reliability and process safety. Valve machining is a critical factor in avoiding hydrogen embrittlement. This includes the machining of all surfaces in contact with the medium as well as suitable welding processes to avoid notches and residual stresses due to local plasticization.
Leakage prevention & testing
Owing to hydrogen's small and lightweight molecular composition, it has a tendency to creep. Guaranteeing a leak-proof valve is essential for maintaining safety and efficiency in hydrogen-related applications. As testing mediums for valves, Nitrogen or helium are advised, as they deliver reliable and reproducible results while circumventing safety and cost issues associated with using hydrogen.
Occasionally, external leak tightness stipulations that surpass standard fundamentals are indicated, potentially necessitating design modifications for the valves. Nevertheless, it is crucial to assess whether these alterations offer any supplementary advantages in light of the mandatory safety measures implemented at the corresponding facility.
Since there's no one-size-fits-all hydrogen valve, it's essential to consider the specific requirements of each application. While standardization around hydrogen as an energy storage medium is still in progress, understanding the different processes can provide guidance towards a decision.
Conventional hydrogen applications including
refining petroleum,
heat-treating metals,
producing fertilizer,
food processing,
and reducing sulfur content in fuels,
present distinct requirements compared to contemporary applications that necessitate high-pressure gas storage and extremely low temperatures. For instance, KLINGER Fluid Control and KLINGER Schöneberg possess a wealth of experience in supplying valves for a wide range of hydrogen applications, providing engineers with a solid foundation for decision-making. This expertise can be relied upon when developing contemporary hydrogen plants, including electrolyzers, storage systems, and pipeline networks.
Double block-and-bleed valves are the safest solution for maintenance.
KHA ball valve fully open.
KHA ball valve completely closed, dead space and ball filled with medium.
Opening of the drain cock. Complete drainage of the dead space and inner space.
KHA ball valve completely closed with opened drain cock. Dead space and ball completely emptied.
One-Size-Fits-All approach
It's important to note that there isn't a single hydrogen valve that meets the requirements for all processes.
“Standardization in the hydrogen energy storage sector is currently trailing behind the rapidly evolving market. Although numerous working groups have been established to formalize and document new requirements, finalizing and approving these standards may take months or even years.”
Ivar Madsen, Managing Director of KLINGER Denmark
Consequently, both users and suppliers are actively seeking suitable guidelines in the face of high demand.
Valve selection: key considerations
The vast array of valves and manufacturers available can be overwhelming. The following considerations might provide some guidance:
Stage of hydrogen process
Blue, grey or green hydrogen
Material of the body, stuffing box, ball and sealing elements necessary
Maximum pressure
Temperature range
In addition, unique challenges might require special valve designs. KLINGER Fluid Control’s solution is the use of special double block-and-bleed valves with a drain valve that provide double shut-off and draining of the dead and spherical interior. This design allows for tightness checks of the ball valve passage while the system is in operation, enhancing safety and efficiency. The Duoball valve, designed by KLINGER Schöneberg, incorporates a dual-ball configuration within a single body, enabling a double block and independent shut-off. This innovative design allows for a potential fourfold increase in safety compared to conventional ball valves.
Compared to standard ball valves, the safety can be increased by a factor of 4 with a Duoball valve by KLINGER Schöneberg.
Addressing challenges and misconceptions in hydrogen valve selection
The fast-paced development of the hydrogen market has resulted in uncertainty among customers and regulatory bodies concerning proper valve selection, material options, testing procedures, and industry standards. The growing support for green hydrogen production and its increased usage has broadened the range of stakeholders involved in the matter.
To address these challenges and dispel confusion, organizations such as the VDMA have issued positioning papers containing recommendations on material selection, industry standards, pressure, and leak tests. Adhering to these guidelines can assist in making informed decisions on valve selection tailored to their specific hydrogen applications.
Collaborating with experienced valve manufacturers
“Selecting the right valve for hydrogen applications requires a deep understanding of material compatibility, leakage prevention, and specific application requirements.”
Gerhard Gruber, Application Engineer at KLINGER Fluid Control
Gruber recommends to:
staying informed on the latest advancements in hydrogen technology,
following guidelines provided by organizations like the VDMA,
and partnering with experienced valve manufacturers.
As the hydrogen market continues to evolve, so will the requirements and standards for valves for applications that produce, process or transport the challenging medium.
Fact Box
Hydrogen, the most abundant element in the universe, has gained significant attention in recent years as a versatile energy carrier in the Power-to-X framework.
Power-to-X (often abbreviated as PtX or P2X) encompasses a range of conversion technologies that transform electricity into environmentally friendly synthetic fuels, including hydrogen, synthetic natural gas, liquid fuels, and chemicals.
These versatile products can be utilized in sectors that are challenging to decarbonize and, unlike electricity, can be stored for future use.
This conversion allows the storage and transportation of energy in a more flexible and efficient manner compared to traditional methods like batteries.
Power-to-X aims to convert surplus electricity from renewable energy sources, such as solar and wind, into hydrogen and other energy carriers through a series of processes known as electrolysis.
What materials should be used for valves in hydrogen applications?
Valves used in hydrogen applications should be made of hydrogen-compatible materials, such as austenitic steel (e.g., 316/316L), to prevent issues like metal embrittlement, increased pressure, and internal stresses. Non-metallic components, such as gaskets and lubricants, should also be hydrogen-compatible to ensure optimal performance.
What are the main questions when selecting a valve for hydrogen applications?
When selecting a valve for hydrogen applications, engineers should consider the stage of the hydrogen process, the type of hydrogen being used (blue, grey, or green), the necessary materials of the body, stuffing box, ball, and sealing elements, maximum pressure, and temperature range. Unique challenges may require special valve designs, such as special double block-and-bleed valves with a drain valve that provide double shut-off and draining of the dead and spherical interior, enhancing safety and efficiency. It's important to note that there is no one-size-fits-all hydrogen valve, and collaboration with experienced valve manufacturers is crucial.
What is austenitic steel and what properties does it have?
Austenitic steel, characterized by a nickel content of over 8%, belongs to the group of stainless steels and is distinguished by an excellent combination of mechanical properties and corrosion stability, making it widely used in areas with high demands on corrosion resistance.
