Carbon Steel Pipe for produced water from skimmer vessel

[MadieKerang]

Dear all, we plan to connect carbon steel line with a main line which is duplex stainless coming from skimmer pressure vessel. I have done the calculation on partial pressure for H2S and it is lower than 3.5 mbar. My question is, can we use Carbon steel pipe such as 516 or A333 to connect to duplex stainless steel ? Is the internal galvanic corrosion is a big issue for this case if partial pressure h2s no longer a valid issue. Appreciate an advise. Thanks

 

[bimr]

The question can't be answered without a water analysis and a description of your process.

Produced water generally has an extremely high chloride content that will destroy the carbon steel so one doesn't understand the concern about galvanic corrosion.

http://www.eng-tips.com/viewthread.cfm?qid=434641

 

I agree with bimr: galvanic effects are secondary when the environment is so highly corrosive. You really only need to assess the carbon steel in this environment in isolation.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[SJones]

Examine the reasoning for having selected the main line in duplex stainless steel, and then do a little thinking as to why it would then be OK to have the same fluid run through a carbon steel line. There are multiple damage mechanisms at play in a produced water system and a bimetallic couple will not be helpful. However, if leaks are tolerable, and you can estimate a lifetime for carbon steel, then it may be that the safety and economic aspects allow you to justify using carbon steel with some substantial corrosion allowance.

Steve Jones
Corrosion Management Consultant

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

All answers are personal opinions only and are in no way connected with any employer.

 

[MadieKerang]

TQVM all...fully appreciate your input.