piping of hydrogen production unit? 2

[treatwater]

In the power plant we use hydrogen to cool generator.
after producing of H2 in electrolyzer,compressing to 130 bar,removing water and O2, we fill the capsules with H2(99% purity).
one of the pipe in the filling station that connect to capsule have been faild and have leakage of H2 and must be replaced. this pipe is Cu alloy and is flexible and coil state to facilitate of connceting to capsule.
how can I find or select the best cu alloy for this purpese?

pl help me.

 

[blacksmith37]

I am not sure I understand the question, but: We have used ordinary 1/4" copper tubing (and Swageloc fittings) with 1800 psi hydrogen for years.

 

[Jmoore1]

whats the service temperature?

 

[treatwater]

( My English language is bad and I am sorry for that)
Thank you Mr. blacksmith37

Are you sure that’s only copper tube and have not any alloying element?
What is the color of the copper pipe? green? Yellow?
Did you have the properties of the tube? Full name (like ASTM A105), thickness, yield strength, ductility, color,…

Please download the Copper tube handbook from this link:

http://www.google.com/url?q=http://...MQFjAA&usg=AFQjCNFXSEjDNH4oUWhb6Igd9ibWM1K89Q

In this book you can see the color code of copper tube.

Unfortunately we don’t have any of these information about coil copper tube in the plant.

 

[iainuts]

Our company uses a large amount of copper tube for hydrogen lines and we don't have any problems with cracking. Steel is a different story because of hydrogen embrittlement, but copper is not affected by hydrogen like that.

Could the problem is fatigue related? Is there any vibration on that particular joint where it failed?

You might also consider a flexible hose at that location. If there's any problem with a very small amount of hydrogen diffusing through the hose (which occurs to various plastic and elastomer hoses), a flexible metal hose would be advisable.

 

[kacarrol]

Air Liquide has a very good online encyclopedia for this kind of stuff (

http://encyclopedia.airliquide.com/encyclopedia.asp)

Hydrogen can be found here:

http://encyclopedia.airliquide.com/...6&UNNumber=&btnMolecule.x=15&btnMolecule.y=14

It says copper is a satisfactory match, as far as material is concerned, with hydrogen but doesn't give a specific composition. From reading the other posts and looking at this information it doesn't sound like you have to worry about the specific composition of the copper pipe with regard to the hydrogen itself.

 

[treatwater]

( My English language is bad and I am sorry for that)
now we use a copper tube, having higher diameter and so rigid in contrast with the earlier one, and when filling the capsule the rigid tube expose to stress for connceting to capsule..is it possible to have a problem in the future?

thanks for your attention.