Material Selection for CO2 service
Material Selection for CO2 service
(OP)
Dear all,
Like you all know that for H2S service there is a NACE MR-0175 that will determine the requirement of NACE approved material for Sour Service (H2S) depends on H2S partial pressure.
My question: is there any similar kind of NACE standard/requirement or else for vapor flow contain CO2.?
What is the criteria (limit) of CO2 (concentration or partial pressure) use for selection of corrosion resistance material rather than using usual carbon steel?
Thanks for any comment before...
regards,
Rayz
Like you all know that for H2S service there is a NACE MR-0175 that will determine the requirement of NACE approved material for Sour Service (H2S) depends on H2S partial pressure.
My question: is there any similar kind of NACE standard/requirement or else for vapor flow contain CO2.?
What is the criteria (limit) of CO2 (concentration or partial pressure) use for selection of corrosion resistance material rather than using usual carbon steel?
Thanks for any comment before...
regards,
Rayz





RE: Material Selection for CO2 service
Carbon dioxide (CO2) corrosion results when CO2 dissolves in water to form carbonic acid (H2CO3). The acid may lower the pH and sufficient quantities may promote general corrosion and/or pitting corrosion of carbon steel.
The partial pressure of CO2, pH and temperature are critical factors.
Increasing partial pressures of CO2 result in lower pH condensate and higher rates of corrosion.
Corrosion occurs in the liquid phase, often at locations where CO2 condenses from the vapor phase.
Increasing temperatures increase corrosion rate up to the point where CO2 is vaporized.
Increasing the level of chromium in steels offers no major improvement in resistance until a minimum of 12% is reached.
The 300 Series SS are highly resistant to corrosion in most applications. Selective upgrading to stainless steels is usually required in operating units designed to produce and/or remove CO2 (such as hydrogen plants and CO2 removal units). 400 Series SS and duplex SS are also resistant.
Luis
RE: Material Selection for CO2 service
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Material Selection for CO2 service
Yes, but chromium in steels offers no major improvement in resistance until a minimum of 12% is reached.
RE: Material Selection for CO2 service
RE: Material Selection for CO2 service
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Material Selection for CO2 service
Cheers,
gr2vessels
RE: Material Selection for CO2 service
dcasto... The 25 psia partial pressure of CO2 is what i'm searching for. However if it not bother you, could you refer me to some document regarding to that value. Anyway thanks for the tips.
cheers,
-Rayz-
RE: Material Selection for CO2 service
Critical factors are CO2 Partial pressure and temperature.
If the corrosion rate for CS is satified, you can apply CS. If not, ASS is recommended.
Ref.
1. C.de Waard and U. Lotz, Prediction of CO2 corrosion of carbon steel, CORROSION/93, Paper No. 69, NACE International
2. CO2 Corrosion nomograph or De waard-Milliams nomograph in website
Cheers,
- Xeros -
RE: Material Selection for CO2 service
Thanks for the information. However i find Norsok M-506 standard that could be useful for CO2 corrosion rate calculation. They offer the calculation spreadsheet too :)Just follow this link..
http://www.standard.no/imaker.exe?id=1369
Thanks for all comments...
-Rayz
RE: Material Selection for CO2 service
; CO2 Corrosion in Oil and Gas Production, NACE TASK Group T-1-3, 1984
RE: Material Selection for CO2 service
http://www.maney.co.uk
It goes through the thought process required when choosing materials for CO2 (sweet) service. Often carbon steel and corrosion inhibition can be a cost effective alternative to CRA materials.
RE: Material Selection for CO2 service
There is not a standard but you can find in NACE website all the articles on this issue and there are also commercial Software dedicated to this type of Corrosion.
Norsok is useful but have some limitations if H2S is contained in the fluid.
Hope this help
regards
Vitt
http://www.corrosionist.com
RE: Material Selection for CO2 service
I've seen a lot of people use non-metallic and stainless flow lines because of fear of CO2 corrosion, and I've rarely seen CO2 corrosion in upstream Oil & Gas operations. It definitely happens, but it is less common than the literature would seem to indicate.
David
RE: Material Selection for CO2 service
I'll show you my library of CO2 related failures. Not pretty viewing. What you will also need to account for are:
Any bicarbonates around in produced water
or
Elevation of the pH owing to gas flashing during sampling.
When you say 'at pipeline temperatures the reaction tends to drive towards carbonate instead of acid', do you mean that the reaction product of the carbonic acid, and its dissociation products, with the iron of the steel pipe tends to form a carbonate corrosion product?
Kermani & Morshed's review: Corrosion, Vol 8, 2003, pp659-683 makes good reading on the subject.
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Material Selection for CO2 service
I certainly don't doubt that CO2 corrosion is a significant problem, I've seen it up close and personal and I believe the literature. My point is that the presence of CO2 is a necessary but not sufficient condition for CO2 corrosion. There are other possible reactions, and many people have over reacted to the possibility of carbonic acid.
David
RE: Material Selection for CO2 service
RE: Material Selection for CO2 service
regards
Vitt
http://www.corrosionist.com
RE: Material Selection for CO2 service