Water pressure test

[europipe]

Is it possible to perform a water pressure test on a pipeline without vents and drains?
How do you get the water on highest points?
I know it´s an odd question but the company I work doesn´t want any assessoires on the pipelines, not even flangeconnections(except on pumps and other mech. items.)
Thanks for your replies in advance.

 

[moltenmetal]

Presumably you have an accessable inlet and outlet somewhere, presumably flanged, correct? That's all you need, provided the pipe is vacuum resistant. Blind the ends, with a drain and vent valve. Pull a vacuum in the pipe and then fill it with water. It will fill completely.

 

[BigInch]

The hydrotest contractor will have to put temporary vents and drains on the ends of the test sections or wherever else he needs them. Those will be installed, used and cut off, or removed with and when the test headers are removed, and then the pipeline segments are joined up without any unwanted appurtenances remaining to spoil the nice view.

http://virtualpipeline.spaces.msn.com

 

[europipe]

Thanks guys, one little continuing question;
can I get the lines dry after testing?(product reacts with water)
Do I have to pull vacuum too then?

 

[GregLamberson]

If the question is - do you have to install additional vents on the pipeline in order to fill & test it - the answer is no. If the question is can you fill & test the pipeline without vents, the answer is impossible.

For many cross-country pipelines, even with large elevation changes, you can fill it with only a vent on the temporary pig trap, i.e. no "extra" ventsi nstalled on the pipeline itself. You run your fill pig with water and with back pressure from your receiver so your pig doesn't run away from the water down a hill and you get a air lock, but other than that - nothing really to it.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[GregLamberson]

europipe

It depends on the dew point you need to dry to and what the pipeline will be used for. Vacuum drying is one method, methanol with pigs is another for higher dew points, compressed dry air, again, it all depends on what dew point you need.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[europipe]

Greg, it's just that we can get the most drops out of the pocket(s) of the line, not really high air humidity.
Hereafter we can blow the line with dry air.
Thanks for your reply.
greetings

 

[GregLamberson]

europipe

Not sure what size or length your pipelines is, but it's not uncommon to run 200-300 foam pigs after running the bulk dewatering pigs.

But again, the method of drying will depend on what product the pipeline will carry. If it;s crude, bulk dewatering & some swab pigs will do it. If it is gas, you will probably need to do some drying and that will depend on what the gas sales agreement stipulates and what, if any gas treatment is available at the end. That will drive the dew point needed. A dew point requirement of -30F is pretty common for a gas transmission pipleine.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[BigInch]

Its not gas or oil, I think its "euros"

http://virtualpipeline.spaces.msn.com

 

[europipe]

liquid euro's.
Maybe(methylamines)
Should be in trade, but I'm just a poor designer.

 

[BigInch]

Wait a minute. Are we talking about filling for test or initial filling? Filling a whole line for testing would have to mean its a pretty flat line, or it would mean a lot of wet work while segments are isolated within allowable test pressure ranges.

http://virtualpipeline.spaces.msn.com

 

[europipe]

Big ", it's a 220 mtr. long 2" pipeline for 100%monomethylamine with pockets, I think greg has a point with his foam pigs after pressuretest with water.
(I knew you people would ask for more details)

 

[BigInch]

Ya wanna' good answer, we gotta' ask good questions.
2" huh? I'm not sure what monomethylamine is exactly, but I'd be tempted to blow it out and dry it with just N2.

http://virtualpipeline.spaces.msn.com

 

[GregLamberson]

Or dump in some methanol and chase it with foam pigs.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[europipe]

That's why your name is Big Inch

 

[BigInch]

Sorry. Probably so. My last "real" job was 800 miles of forty-2". But you should be able to get enough N2 to dry that one out. If not, as Greg says, use the methanol.

http://virtualpipeline.spaces.msn.com

 

[dcasto]

Use nitrogen to test. If you must use water and need a low dew point dry, a vucuum won't work, use dry air to get the dew point below -50, then use nitrogen to get lower. see

http://www.bjservices.com/website/index.nsf/P&S?openframeset

 

[DavidMc]

dcasto has the best answer to keep it simple. Nitrogen is the best way being a dry gas to begin with it would eliminate any moisture in the line. The down side of compressed air or gas is that it can be dangerous! Where a hydro test is the safest. A hydro will never hold a steady pressure to document unless all air is eliminated from the line. If you where to successfully hydro the line and run a pig through the line to clear the water but still needed it completely dry tape up the ends and purge it with Argon it will definatly complete the drying cycle! I'm not positive on this but Argon I believe is the dryest of all gases .Being a pipe welder by trade I'm aware of the problem you are dealing with I just hope I may have helped you out in some way.

 

[europipe]

Can't use nitrogen to test.
It's not allowed to test with a gas higher then 6 bar.
Still got the problem with loosing the water in lowest points.
Got to dry it with air, I think.

Thanks for all your replies.