×
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

Sour Water Stripper Internals

Sour Water Stripper Internals

Sour Water Stripper Internals

(OP)
We have plans to revamp a Sour Water Stripper using 316L stainless steel internals. However, we anticipate that at times there may be high Chloride content in the sour water due to leakage on seawater condensers, of which we have a few. This may be more for a metallurgist, but if anyone has looked at a sour water stripper recently I would appreciate any info you may have.
Generally I know that 300 stainless steels and high Chlorides don't go together. However, you should not get more than 275 degF or so in this column. Does that make a difference?

RE: Sour Water Stripper Internals

Hi Petro...

Our guidelines in simplified terms state that <65DegC and <50ppm will keep the risk of SCC at a minimum.

If you add any H2S, pH changes, stress etc then all bets are off.

Quite simply, in terms of pressure containment, if there's a risk of chlorides mixing with S/S then the best course is to remove either the chloride or the material. Try duplex. Open literature is overflowing with the cautions against austenitic SS and chlorides.

Limited time of exposure is not a justified arguement either. One taste could set off SCC.

On the other hand, you might not care if non pressure containing kit develops some SCC. I'm not sure if I would care providing I had a shortish inspection interval.

What's the stripper made of?? Are internals made of the same material feasible?

Cheers

Rob

RE: Sour Water Stripper Internals

Some comments:

1. Seawater presence from leakages may oblige the use of titanium grade 2, and probably preclude the use of stripped water in the desalters, until the leaks are stopped.

2. When using overhead condensers steam tracing and insulation of overhead piping as well as water washes are effective in removing plugs from salt (plugging) deposits formed below the minimum recommended temperature of 180oF.

3. When treating cyanide-containing sour water (as from FCC units) overhead condensers require titanium to prevent corrosion under deposits.

4. Modern sour water stripper cooling systems are based on pump-arounds rather than overhead condensers. There is less corrosion and no sublimating (ammonium) salt deposits because these are liquid-filled systems.

 


RE: Sour Water Stripper Internals

(OP)
Thanks to both of you (robslav & 25362) for the information. I suspected there would be a problem. The stripper is Carbon Steel with a cement-type lining. We will be processing FCCU water but we use a pumparound. To my knowledge, this may well be the first use of this material for trays in our refinery, but I believe the case will be pretty strong. I will be forwarding this thread to the engineers responsible for preparing the BEP.

RE: Sour Water Stripper Internals

One comments.

I think you'll need to  have a look at the NACE MR 0175 which gives guidelines to materials selection for Sour Service and gives limits for Temperature, Cl concentration e H2S contents.
This standard is more concerning Oil and Gas production, but i think can give you an idea of the application limits for AISI 300 class.

Hope will help.

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