Material compatibility for oxygen service

[TomaszKruk]

hello,

I have a question about resources evaluating piping material compatibility for oxygen service. We are using EIGA documents, but they recommend Inconel / Monel / Hastelloy for pressures above 4,0 MPa. And that's it. I was hoping to find some data regarding possibility of using stainless steel instead, since this is what is working on the plant right now. Wall thickness adjusted, ofc.

I cannot go into details, but it's oxygen pressured to around 40 bar, gas velocity around 12 m/s, temperature 150oC.

Can you recommend where to look? Any thoughts regarding material selection? Nickel alloys are recommended - should I not trust my lying eyes that see stainless there?

Regards,

 

[EdStainless]

Old NASA docs.
Such as Ignition of Metals in Oxygen, DMIC report 224, Feb 1, 1966
In my experience I have seen the restriction to Ni alloys only in breathing systems. SS is commonly used at these intermediate temperature and pressure. Look into the CGA guides

https://portal.cganet.com/Publication/index.aspx

Valves and regulators are still issues, we always used Co alloys in control valves and Ni alloy regulators.

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P.E. Metallurgy, consulting work welcomed

 

[EdStainless]

And

https://www1.grc.nasa.gov/wp-content/uploads/chapter_05.pdf

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P.E. Metallurgy, consulting work welcomed

 

[1503-44]

These may be of help.

http://asiaiga.org/uploaded_docs/AIGA 021_12 Oxygen pipeline and piping systems.pdf

NFPA 55

https://www.nfpa.org/Codes-and-Standards/All-Codes-and-Standards/Free-access

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

 

[jojoyohan]

Take a look at EIGA 13 (

https://www.eiga.eu/index.php?eID=d...en=2d624a7e3856ad72e77bdf03ce1c3b5570c6942e),

particularly section 4.4. It looks like you're just above the velocity exemption curve at 4 MPa.

 

[csk62]

Acceptable velocity/pressure combinations are dependent upon if the component in question is an impingement site or not.

 

[georgeverghese]

The 30barg pure O2 compressor I used to operate had O2 at 30barg and 150degC in SS316L. Make sure all SS316L pipes, fittings and valves are well degreased. Insist on material certs for SS316L to be sure. 12m/sec sounds a little high, but may be ok.

 

[EdStainless]

There are CGA specs for 'cleaned for oxygen service'. All valves, regulators, and fittings must be individually bagged and certified to such a spec. It costs money but is well worth it.
At these velocities we went to Ni or Co alloys for control valves and regulators.
I never had it happen but I have seen the aftermath of a regulator failure, that then burned.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed