Material to use for high pressure high temperature sour gas tubing

[gtillman]

Working on a project with 25000psi 400degF sour gas, 50ppm H2S, 5% CO2 and up to 50,000ppm chlorides. Current plan is to use annealed S316000 cone and thread tubing and valves for the instrument and control tubing lines. MR0175 table A.2 indicates the material is only acceptable up to 140degF but table A.4 would indicate that the material has been used for these conditions without restriction on temperature, H2S partial pressure, chlorides contens, etc in production environments.

Which table should be used?

 

[moltenmetal]

The table for Hastelloy C...

 

[SJones]

Good question, and one that throws up the clash of the grandfathered NACE approach versus the ISO approach of testing to qualify that confuses people by being placed in the same document. How lucky do you feel? As an example, Shell treat 316 as 316 irrespective of what application it is in. Also don't forget that 316 can crack from the outside.

For the stated service conditions, you may find reference to the Institute Of Petroleum Guidelines For The Management, Design, Installation And Maintenance Of Small Bore Tubing Systems to be of use.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[gr2vessels]

gtillman,
I am having trouble reading your post. Is it gas or liquid in your tubing? If it is gas, where and how do the chlorides fit in the picture. If it is liquid, where did you get the sour gas from?
Remember, the MR0175 refers only to the liquid phase, containing water and contaminants. The temperature, pressure and composition you mentioned (no H2O!!) seems to be suitable for any material, including carbon steel. In fact, if you take in account the start-up and shut-down conditions (I make assumptions of condensation and presence of water!!), the 316 is less resistant than the carbon steel. Give us some more details for a better answer to your case.
Cheers,
gr2vessels

 

[gtillman]

The application is natural gas at the wellhead. It will contain both produced water with high chlorides and condensate. After spending more time with MR0175 it looks like super duplex 2507 is acceptable and is semi available in cone and thread tubing