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Need a Quick Pressurization Quantity calculation check

Need a Quick Pressurization Quantity calculation check

Need a Quick Pressurization Quantity calculation check

(OP)
I am trying to figure out how much gas I need to pressure test a line.  I have 300' of 20" pipe.  I will fill with compressed air to 100 psig, and then I need to use a nitrogen tanker to boost it up to 250 psig.  I am trying to figure out how much nitrogen.  Here is my thinking:

Volume = (pie/4) * 20^2 * 300 / 144 to give me 655 cubic feet of pipe.  I used the 20" OD to give me a cushion.

So for every 655 cubic feet of gas I introduce into the pipe, the pressure should reaise by 1 atm or 14.7 psi, correct?  If so, then in order to get from 100 psig to 250 psig, I need:

(655 cuft)(150 psi / 14.7 psi) = 6684 cuft.

Agree?

RE: Need a Quick Pressurization Quantity calculation check

close enough, you should compensate for supercompressilbilty and temperature too.  Why not continue with air?  Or do you need an inert buffer.

RE: Need a Quick Pressurization Quantity calculation check

(OP)
The house air only goes to 100 psig, and they want to test at 250 psig

RE: Need a Quick Pressurization Quantity calculation check

It will depend on your wall thickness, but using a 20" x .500" I get about double your calculations (almost 12,000 cu ft).

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com

RE: Need a Quick Pressurization Quantity calculation check

Oh crud, I used a gas line pack spreadsheet I have and the way the formula is put in, I doubled the distance.  My apologies to all - thanks for the catch BigInch.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com

RE: Need a Quick Pressurization Quantity calculation check

Could have sworn it was a D^2/2 thing.  Either that or the hole was on the outside.  

I want to write D^2/2 all the time.  My trouble is that they taught me A = pi*R^2 back in gradeschool.  Guess they didn't know I was gonna' be a pipeliner.

cheers

http://virtualpipeline.spaces.msn.com

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