×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

pitting corrosion on 316/316L methanol pipeline in marine environment

pitting corrosion on 316/316L methanol pipeline in marine environment

pitting corrosion on 316/316L methanol pipeline in marine environment

(OP)
I have pitting corrosion, possibaly initiated by stress corrosion crack under chloride ion effect, on external side of 316 stainless steel pipework. It is also suggested that it could have been started due to deposit on the surface, which i cant confirm. It was used under open environmental conditions for three years handling methanol, after which leaks were found. the whole pipework can't be removed due to ecnomical reasons.
Any remidial suggestions are welcome. What should i do to atleast reduce the corrosion rate externally.
Regards
Ejaz

RE: pitting corrosion on 316/316L methanol pipeline in marine environment

Have you tried cathodic protection?

RE: pitting corrosion on 316/316L methanol pipeline in marine environment

For corrosion control you have 4 options:

1.  Change the material
2.  Change the environment
3.  Provide a barrier between environment and material
4.  Provide cathodic protection

It would appear that 1 is out.  2 is not possible.  4 is not effective in 'open environmental conditions'. That leaves option 3.  In situ painting is going to be a bit tough.  BP have investigated application of chemicals and had some success but were not hopeful of chemicals getting in to protect crevices under clamps etc (the same will go for paint) - see NACE Corrosion 2010, Paper 10305.

 

Steve Jones
Materials & Corrosion Engineer

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

RE: pitting corrosion on 316/316L methanol pipeline in marine environment

Steve,  Could you expound on the "not effective in 'open environmental conditions'".  I'm thinking that there may be a huge problem with whole lot of Gulf of Mexico, and no telling where else, offshore pipelines that rely only on asphalt coating and CP.

RE: pitting corrosion on 316/316L methanol pipeline in marine environment

I'm taking the methanol system to be topsides in the atmospheric zone and uncoated, i.e. 'open environmental conditions'.  Being in the atmospheric zone, CP will not be an effective option.  Don't panic about the pipelines (yet!).

Steve Jones
Materials & Corrosion Engineer

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

RE: pitting corrosion on 316/316L methanol pipeline in marine environment

Good.  I was hunting around for my VPPE.
Thought you had a new study to spring on me.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources