FITOK Specialised Products Contribute to Safe and Sound Hydrogen Applications

To alleviate the global warming caused by accumulated greenhouse gas emissions, major economies in the world are committed to achieving the goals of “peak carbon emissions” and “carbon neutrality”. Hydrogen, as one of the clean energy sources to replace traditional fossil energy, whose applications are regarded as the main technology direction of the future energy revolution, is therefore gaining increasing attention. Among the many applications, hydrogen fuel cell vehicles and hydrogen refuelling stations are in the spotlight of governments and the industry. For instance, both China and Germany released strategic plan on the development in this field.

With the rapid development of hydrogen fuel cell vehicles and the continuous growth of hydrogen refuelling stations and other infrastructure construction, common problems in hydrogen applications such as easy leakage, hydrogen embrittlement, and high pressure and low temperature working conditions are also becoming more and more prominent, and how to ensure the safety and reliability of hydrogen systems has become one of the key concerns in the industry. Therefore, selection of suitable products with high safety in different applications is the optimal solution for a safe and reliable hydrogen system.

How do FITOK products and services ensure the safety and reliability of hydrogen systems?

Raw Materials and Hydrogen Embrittlement Resistance

Hydrogen embrittlement is a phenomenon in which hydrogen atoms enter the lattice voids of a metal and move diffusely, causing cracks in the material at the defective location after the atoms have recombined or reacted with other substances to form gaseous molecules, resulting in rapid volume expansion leading to cracks at this location. The hydrogen embrittlement cannot be eliminated once it occurs, so it can only be prevented.

Experiments have proven that stainless steels with nickel content greater than 12% and nickel equivalent not less than 28.5% have excellent resistance to hydrogen embrittlement. FITOK has developed the raw material of enhanced-316/316L (designator SH) for hydrogen applications in accordance with industry standards, which has good resistance to hydrogen embrittlement under high pressure and can meet the requirements of various international standards.

O-Ring: Low Temperature and Pressure Cycle

Low Temperature: Hydrogen needs to be pre-cooled before being charged to the fuel cell vehicle to prevent the risk of tank rupture due to exothermic expansion, and low temperatures can cause the O-rings to lose elasticity and thus lead to seeing failure.

Pressure Cycle: From the filling of hydrogen to the pressure relief, the non-metallic O-rings of valves and fittings will undergo repeated pressure changes under 0 MPa to the maximum working pressure, and the small molecules of hydrogen will leak into the inside of O-rings under violent pressure changes, and the hydrogen molecules make the O-ring surface blister or even crack under the violent pressure change.

FITOK provides low-temperature O-rings compatible with hydrogen applications to products suffixed with -H2 and -EC79, which maintain consistent high reliability under extremely harsh working conditions.

Sealing and Vibration Resistance

Hydrogen’s small molecules are easy to leak and may cause safety accidents. At the same time, hydrogen compressors are one of vibration sources, thus require fittings and valves with excellent vibrations resistance. FITOK tube fittings, manufactures with special customised high nickel and high chrome raw materials, after advanced design and manufacturing process as well as hardening treatment to rear ferrule surface, boast excellent sealing and vibration resistance performance in extreme environment.

Tubing For Hydrogen Applications: Material Nickel > 12%, Nickel_eq ≥ 28.5%

• Medium pressure tubing (138 MPa, T20D Series)
• Medium pressure cone and thread (C&T) tubing (138 MPa, T20M Series)
• Instrumentation tubing (83 MPa, TMP series seamless straight tubing and TCT series seamless coiled tubing)

For an more information into how FITOK specialised products contribute to safe and sound hydrogen applications please contact our sales team: sales@nvfcl.com or call 01942601209