HYDROGEN
Fiber-based gasket materials for hydrogen applications
This article discusses the importance of hydrogen , followed by the challenges of sealing hydrogen and comparing the leakage performance of fiber-based gasket materials between hydrogen and helium .
By Anna Berger , Frenzelit
Figure 1 – Alkaline electrolysis as an example for gaskets in hydrogen applications . Depicted is an electrolyser stack with the gaskets highlighted in green .
The current search for alternative sustainable energy sources that generate significantly lower CO 2
-emissions has led to an increased interest in hydrogen in recent years . At the moment , most hydrogen which is used in industrial applications is so-called “ grey hydrogen ”, which is produced in a steam reforming process , where fossil energy ( e . g . natural gas ) is used , and the greenhouse gas CO 2 is released in the atmosphere as a byproduct . Grey hydrogen is therefore not climate-neutral . However , hydrogen has many properties , which make it interesting as a possible alternative to fossil fuels . The main reason is that it can be generated in a climate neutral process via electrolysis using only water and renewable energy . Hydrogen which is produced with this process is referred to as “ green hydrogen ”. Another important advantage of hydrogen is the high versatility it provides . It has a high energy density and can therefore be used as an energy source , for example as a direct replacement for natural gas in combustion processes , or by transferring it into electric energy in a fuel cell . Alternatively , hydrogen can also be used as a starting material for various power-to-X processes . This means that hydrogen is converted to other substances that are easier to store and transport than hydrogen and can either also be used as fuels or as starting materials for further processing ( e . g . ammonia , methane or methanol ).
Gaskets in hydrogen applications
For every hydrogen application , there is a need for efficient and well-performing gaskets to prevent hydrogen-leakage . The requirements for gaskets in these applications are as diverse as the hydrogen applications themselves and can be quite challenging in some cases . Some hydrogen applications require extreme temperatures , ranging from cryogenic applications with liquid hydrogen at very low temperatures ( - 253 ° C ), to temperatures up to 1000 ° C in solid oxide fuel cells or high temperature electrolysers . Different processes also require chemical resistance against various different media , for example against oxygen in combination with potassium hydroxide in alkaline electrolysis . Apart from chemical resistance , gaskets which are used as stack gaskets in electrolysis ( figure 1 ) and fuel cell applications usually also have to be electrically insulating , have a high mechanical stability and a defined relaxation behaviour .
Challenges of sealing hydrogen
However , no matter how different the requirements for gaskets in hydrogen applications are , all of them have one common task , which is that they have to seal the challenging medium hydrogen as well as possible . The leakage performance of flat gaskets is usually determined in tests using nitrogen or helium as a test gas . For the gasket characteristics according to the European standard EN 13555 , which are
22 Valve World February 2025 www . valve-world . net