AISI316 pipe carrying CO2 at temp above 60deg C 2

[Spiralis]

I want to use a test flow loop of Aisi316 stainless steel, to performe fluid test of a hydrocarbon gas with high CO2 content. The H2S content is very low and there is no water in fluid and no chlorides (the customer hope there is no chlorides present). The customer now tell us that they have been told that Aisi316 can be a problem (cracking) when the temperature is above 60deg C (140deg F). The spec is 100bar at 100deg C (212deg F). The unit is used for testing and not a permanent installation. The case her is that the unit will be coupled together with duplex steel flanges for 10-14 days.

Is there som reference telling about this issue for problem with CO2 in temperaures above 60deg C when using Aisi316 or Aisi304 stainless steels?

 

[EdStainless]

You need to specify a Weld Decay test per ASTM A249 S7. Even though the pipe will not be made to this spec.
If the welded pipe is under annealed you will eat the ferrite out of the welds.

Be careful about the chorides, even a few ppm could give you CSCC problems.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[SJones]

Take a look at this paper for application limits of 316 (L)

http://www.nickelinstitute.org/inde...ords=Craig&ci_id=6511&Submit.x=12&Submit.y=8.

14 days should not give you a problem and neither should coupling to duplex (no electrolyte anyway). Trust the test unit will not be located on a beach or offshore installation to give you problems from the external environment.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[Spiralis]

SJones,

Thank you for directing me to this paper. The figures is informative and gives me the answers I am looking for.

The diagram in the paper gives information about combination of CO2 (partial pressure) and NaCl (g/l).

As the document states: The alloy must be used with care as oxygen and H2S in small consentrations will have a profound effect on the resistance of alloy 316 to corrosion and cracking.

If somebody is looking for the same info with duplex and 13%CR steels, this is the paper to read.