Hydrogen (H2) Sealing Solutions
As countries worldwide pivot towards sustainable energy solutions, hydrogen is emerging as a key focus in this transition. Both as a fuel and as an energy storage medium, hydrogen is vital for harnessing surplus energy from renewables. Its usage is has many complexities, particularly in the realm of sealing technologies.
The energy transition and hydrogen’s role
Hydrogen’s (H2) utility lies in its ability to serve as a versatile energy vector. It can contribute to reducing carbon emissions and propelling the world towards a net-zero future. Available naturally in a gaseous state, hydrogen turns into a liquid at -253°C, facilitating easier storage and transport due to the increased volume capacity. This dual state presents a host of technical challenges and opportunities.
Hydrogen safety: a complex equation
Hydrogen comes with unique safety implications, given its lower ignition temperature and oxygen content requirements compared to natural gas. Also, its fast-burning nature and higher combustion temperatures necessitate rigorous safety protocols. Measures must be taken to prevent uncontrolled releases, leaks, or potentially devastating explosions. In this context, sealing solutions are crucial.
Sealing challenges
When it comes to hydrogen sealing, issues generally fall into these key categories:
- Temperature Extremes: Hydrogen production, especially through prevalent methods like Steam Methane Reforming (SMR), involves high temperatures that can degrade materials.
- Chemical Interactions: Hydrogen can adversely affect metals, causing phenomena like hydrogen embrittlement and induced cracking.
- Physical Interactions: Hydrogen’s properties can change when in contact with polymer-based materials, affecting the integrity and performance of the seal.
- High Pressure: Hydrogen storage and transportation often occur under high pressure, which puts considerable stress on sealing materials and components.
- RGD (Rapid Gas Decompression): This is a particular concern in hydrogen applications where pressure changes occur rapidly, potentially damaging the seal if it is not appropriately designed.
- Permeability: Due to hydrogen's small molecular size, the material used for sealing must have low permeability to prevent leaks.
Considering these complexities, selecting the optimal material for sealing solutions is of the utmost importance. To make an informed selection for hydrogen-related applications, the following must be considered:
- Chemical Compatibility: The selected material must exhibit resilience against hydrogen’s reactivity, which can be pronounced under conditions of elevated pressure or temperature.
- Temperature Tolerance: The material should possess the ability to resist degradation across the wide temperature variations commonly encountered in hydrogen applications.
- Mechanical Durability: Due to hydrogen's diminutive molecular size, a material with superior mechanical strength is required to mitigate risks of permeability and leakage.
- Aging and Weathering: The material should demonstrate enduring robustness against long-term exposure to various environmental factors, including ozone, UV radiation, and other potentially degrading elements.
Materials for hydrogen sealing solutions
Given the intricacies discussed above, sealing solutions often require a multifaceted approach. They frequently integrate several types of materials, including metals. Therefore, the selected polymer must be compatible with these additional materials to ensure the system's overall integrity.
Also, due to the safety-critical nature of hydrogen applications, any chosen polymer should adhere to all relevant safety standards and guidelines. This includes both industry-specific and governmental regulations.
Here are some of the materials that meet the above criteria:
- Fluoroelastomers (FKM)
Chemically resistant and has a wide temperature range, making it suitable for different conditions in hydrogen storage and transport. - Perfluoroelastomers (FFKM)
Exceptional chemical resistance and can withstand extreme temperatures. It is used in settings that require high levels of purity and can operate under extreme conditions. - PTFE (Polytetrafluoroethylene)
Known for its chemical compatibility and low coefficient of friction, making it suitable for sealing applications where chemical reactivity is a concern. - Ethylene Propylene Diene Monomer (EPDM)
Resistant to ozone, weather, and aging. However, it is generally less resistant to oils and fuels, so its use in hydrogen applications would depend on specific conditions. - Polyurethane
This material is known for its excellent wear resistance and is often used in dynamic sealing applications. However, its compatibility with hydrogen needs to be carefully assessed.
Here to help
Navigating the complexities of sealing solutions for hydrogen applications can be a difficult task, so our team is on hand to assist with your enquiries.
Whether you have questions about material compatibility, safety standards, or anything else related to hydrogen sealing technologies, we encourage you to contact us and speak to our of our technical team.