Flanged or welded connection for blowdown vessel

[MechMad1]

I have a drains-collecting-manifold that is connected to a flash tank (a blowdown vessel). The fluid is a mixture of steam and water, at aprox. atmospheric pressure.
I've seen some vessels that have a welded connection (between vessel and manifold) and others that have a flanged connection.
And I don't know if there is a particular reason to use one or the other.
Flanged connection offers a better maintenance but are more likely to have leaks.
Any other point!?
Thank you!

 

[MJCronin]

The location that you describe is the area on the vessel subject to extreme erosive flow.

An increased wall thickness (over simple pressure requirements) and a butt welded joint is recommended in this area.

I have found very little guideance about recommendations in the design of flash/blowdown tanks.

Also, the tanks will not last forever....count on a full replacement ~ 10-12 years...... IMHO

 

[MechMad1]

Thanks MJCronin, that was a very good point.
Let's say that from the process point of view, the buttweld is the preferred connection. I agree.
Is there other considerations that we should take into account? I'm thinking for example the hidrostatic test, or when having to weld the connection (maybe the supplier of the tank has something to say?), ...