Liquid CO2 Pipeline
Liquid CO2 Pipeline
(OP)
Hey Everyone,
I'm new to the forums and had a question regarding the design of liquid CO2 pipelines. The pipeline is around 180 miles long, and 8" O.D. The end pressure needs to be around 1200 psi. Now, PipeCalc is the software that I am using for my other long distance pipeline calcs. However, I'm not sure which equation would best govern the behavior of liquid CO2. Does anyone have any suggestions as to what equation would effectively model the behavior of liquid CO2 and take into account effects from change in elevation.
Thanks,
Robert
I'm new to the forums and had a question regarding the design of liquid CO2 pipelines. The pipeline is around 180 miles long, and 8" O.D. The end pressure needs to be around 1200 psi. Now, PipeCalc is the software that I am using for my other long distance pipeline calcs. However, I'm not sure which equation would best govern the behavior of liquid CO2. Does anyone have any suggestions as to what equation would effectively model the behavior of liquid CO2 and take into account effects from change in elevation.
Thanks,
Robert





RE: Liquid CO2 Pipeline
If your flow rate is less than Q then you have some serious problems ahead of you. First, some of the CO2 will flash as it goes over hills--flashing CO2 can get really cold and 180 miles of cryo pipe is pretty expensive. Second, you have to provide pumping hp to overcome the hydrostatic head of the highest hill.
You need to provide more info if you want a decent response.
David
RE: Liquid CO2 Pipeline
I dont follow you. What do you mean by "running full"? Surely you can operate a line full of liquid at 0.00000001 m/sec liquid velocity? It sound to me that you are thinking about a selfdraining pipe?
Robert be aware that co2 is not a typical compound and that many simulator will have problems - especially if you a close to the L/V interface. Get a Moillier diagram and check. You should rememeber to do a "slag flow" check (is that what you are aiming at zdas04 although i cant see how this would be a problem running at low velocities). By this i mean check that the pressure when going uphill dosnt cross the flash point at the given temperature when the pressure in the pipeline decreases due to loss of static head going uphill.
For your reference i have a link to an excellent little co2 thermodynamics primer incl. a good Moullier diagram here:
http://www.union.dk/media/CO2-GB.pdf
Best regards
Morten
RE: Liquid CO2 Pipeline
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Liquid CO2 Pipeline
I do a lot of work with produced water lines in the Rockies and a lot of what I do is troubleshooting why pump discharge pressures are significantly higher than design. What I generally find is that if the flow rate is less than the "Sealing Flow Rate" equation above, that the downhill portions will outrun the uphill portions and result in a discontinuous fluid system (i.e., gas or steam breaks out and collects on the top of hills and you don't get the rebound effect on the downhill part). This negates any "monometer effects" and results in phase change and high discharge pressures.
David
RE: Liquid CO2 Pipeline
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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: Liquid CO2 Pipeline
RE: Liquid CO2 Pipeline
**********************
"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: Liquid CO2 Pipeline
RE: Liquid CO2 Pipeline
I think BWR would be OK, as long as you stay above 1150 psig and temperatures remain close to normal ambients.
Whether your software will handle 2 phase flow, or slack flow, is another question, most don't. And if they do, you can't count on getting a close approximation to what you may eventually see out there, so its best to work with conservative ranges and STAY well inside the full flow liquid range.
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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: Liquid CO2 Pipeline
At 1200 psi there is not much difference between the densities of liquid and vapor CO2, so the VLE modeling may not be too critical.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Liquid CO2 Pipeline
Best regards
Morten
RE: Liquid CO2 Pipeline
Best regards
Morten