Distance between pigs during commissioning of a new pipelin
Distance between pigs during commissioning of a new pipelin
(OP)
Hi all,
My company will start a new oil pipeline. The builder will deliver it just after removal of the water used for hydrotest, so the pipe will be wet and full of air at atmospheric pressure.
We decided to send a train of 3 pigs (nitrogen + nitrogen + oil) to clean and dry the pipeline.
My question is: what is the minimum distance between pigs?
The pressure will be between 7 and 10 barg (the first step will be to fill the pipeline with air at this pressure), the pigs should run at about 0.8 m/s.
Thanks.
My company will start a new oil pipeline. The builder will deliver it just after removal of the water used for hydrotest, so the pipe will be wet and full of air at atmospheric pressure.
We decided to send a train of 3 pigs (nitrogen + nitrogen + oil) to clean and dry the pipeline.
My question is: what is the minimum distance between pigs?
The pressure will be between 7 and 10 barg (the first step will be to fill the pipeline with air at this pressure), the pigs should run at about 0.8 m/s.
Thanks.





RE: Distance between pigs during commissioning of a new pipelin
RE: Distance between pigs during commissioning of a new pipelin
RE: Distance between pigs during commissioning of a new pipelin
Then run pig with the oil.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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"Life is nature's way of preserving meat" The Master on Dr. Who
RE: Distance between pigs during commissioning of a new pipelin
Best regards
Morten
RE: Distance between pigs during commissioning of a new pipelin
If you just have to do it, assume air at 100% humidity, for which @ 70 F has 1253 lbs of water (150 gal) per 1,000,000 cubic feet. Clean with superdry air, do as Morten suggests and run a batch of MEG, or N2. Those are the 3 cheapest methods, usually in that order.
Before starting ANY drying be sure to clean the line with wire brush pigs followed by soft foam pigs. Weigh pigs before and after. When they are about the same weight, you've got all the water you're going to get with the foam pigs. Then start the drying opeation.
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Distance between pigs during commissioning of a new pipelin
thank you for your guidance.
Biginch > actually, it's not crude oil, but stabilized oil (so it's dry). thanks for the info about the cleaning sequence for cleaning (with brush pigs and soft foam pigs, I'll keep it in mind for the future). Unfortunately, I don't decide of these subjects, I just have to write the procedure...
In that project, recovery/disposal of any product is not an easy part (and moreover, it has not been taken into consideration in the budget...), so MEG is not suitable. N2 has been chosen because, well, you know, it's just vented at atm...
So I think I'll go on with the calculation. Thanks for water content of saturated air.
RE: Distance between pigs during commissioning of a new pipelin
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Distance between pigs during commissioning of a new pipelin
RE: Distance between pigs during commissioning of a new pipelin
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/