Seminar: "Ready for H2: Expertise that creates trust!" on 17th January 2024
The questions of the seminar attendees were compiled and answered by our Technical Director, Mr. Guido Drissen, as follows.
Can you tell us what specific materials are used?
For metallic parts, only high quality stainless steel such as 1.4404 is used (this can also be seen in the data sheets of the individual valves). This material is safe to use which has also been confirmed by the DIN standardization committee.
For the polymers, different materials can be used. In any case, the compounds are composed in such a way that they have low permeation, since hydrogen is a very small molecule. The suitable material is supplied by the manufacturers.
Specifically for the electrolysis sector, Mankenberg uses elastomers that are peroxide-cured because these do not impair the function of the electrolysis stack. No sulphur-crosslinked material must be used.
Do the valves have various local approvals such as Korea Gas Safety Corporation KGSC?
No.
Stellite as hardened is OK for this process?
No information available because this does not apply to Mankenberg products.
When there is a mix process like Natural Gas + Hydrogen, is the material similar?
In general: yes. Individual cases must be discussed with Mankenberg’s experts.
Is any special cleaning needed for hydrogen service?
With regards to the topic treated during the seminar: yes. This is essential for electrolysis applications because it is important to work with the cleanest (deionized) water, i.e. pure H2O. The application of certain standards is still being investigated, e.g. EIGA.
How to maintain?
This question is not clear enough to be answered.
Which medium is used to test the tightness and seat tightness of a hydrogen valve?
Water and/or nitrogen. We randomly validate our process with a helium leak test.
Is no strength test performed?
This depends on the system and is not a specific requirement. In such cases, this must be clarified with the manufacturer. So far, Mankenberg has mainly manufactured with threaded connections.
Which flange shape is recommended for flanged H2 valves (gaseous, not liquid) up to PN 100?
This depends on the system and is not a specific requirement. In such cases, this must be clarified with the manufacturer. So far, Mankenberg has mainly manufactured with threaded connections.
How do you check whether H² or only an H(+) ion diffuses through a seal during leakage measurement (application at high temperatures)?
Mankenberg does not. Our hydrogen applications are only available as H2.
Is this for a test with liquid hydrogen? In the case of gaseous hydrogen, air is around 14 times lighter than hydrogen and therefore much less volatile than air. Wouldn't it be better to test with helium?
The test is with water and/or nitrogen. We randomly validate our process with a helium leak test.
And what is the durability of seals for H² applications (hydrogen embrittlement)?
Mankenberg has soft seals, which are not susceptible to hydrogen embrittlement.
How much influence does the DVGW have on the testing and certification of H2 valves and which manufacturers are interested? e.g. ZP 4110. o. DVGW G406
DVGW is not applicable to Mankenberg’s electrolysis applications.
The leak test with hydrogen as part of the DVGW G 406 production test can be dispensed with if: The leak tests with different test gases (e.g. N2 or helium or similar) are verified. For these alternative test gases, leakage rates that were not determined with hydrogen must be converted into equivalent rates and certified.
This is only a remark and not relevant for Mankenberg.
Would we recommend metal-to-metal seat or can a soft seal O-ring be specified for H2?
Not applicable for Mankenberg.
What is the material of the inside gasket (under seat or between body and bonnet)? Can 316L + graphite (wounded) be used?
For profile lip seals we use EPDM and graphite for flange connections.
Also for packings and balance seals and PTFE be used?
PTFE is available at Mankenberg for other tightness classes.
Are your products certified for marine classifications ? ABS BV LRS ...
Yes.
Is there any elastomeric sealing in the valves?
Yes.
Thank you! You have shown a variety of solutions for H2. Have you got some recommendations (partner companies) for storage and compression?
This must be individually discussed for every project.
What will be the solution for H2 in urea plants even if H2 removal is not good as solution?
Not applicable for Mankenberg products.
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