Liquid removal from a pipeline
Liquid removal from a pipeline
(OP)
My company manufactures a heater used to heat a thermofluid which is then transported around an asphalt plant to keep the asphalt hot. Inside the heater is a large helical coil through which the thermofluid flows. Before shipping, we test the heater with thermofluid. The problem we're having is removing the thermofluid after testing is completed, and since the helical coil is so large, this adds a significant amount of weight to the heater, making it more expensive to ship. The thermofluid is basically an oil. Is there any way to effectively and cheaply remove this oil from our coil? I've looked at pigging, but I'm wondering if there are other ways possible. Thanks for any help.





RE: Liquid removal from a pipeline
RE: Liquid removal from a pipeline
RE: Liquid removal from a pipeline
The most efficient and effective way to do it is to put a turbo pig in the line and blow it out with compressed gas (either nitrogen or an air compressor). You will be amazed at how effective this is and with how little pressure and time is required to run the pig. You'll wonder why you resisted pigging (in fact I'm already wondering that).
Blowing the oil out without a seal always causes bypassed flow. It will take between 5 and 30 pipe volumes to blow the oil out without a pig. With a pig going in high on the system, you can do it with less than twice the pipe volume of gas. If you can't go in high on the system, then you'll have to raise the pressure high enough to overcome hydrostatic pressure and you'll use a bit more gas.
David
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Liquid removal from a pipeline
RE: Liquid removal from a pipeline
David
RE: Liquid removal from a pipeline
How much time are you allowing for draining? You can drain 95% of the oil in a 2 inch flex hose in 4 minutes, then we had to wait 2 days for the rest to ooze down and out recently while trying to ship out an oil flush rig. .
If you're worried about weight, just drain the 90% amount that flows out quickly, drive to the next station, re-load. (Are you sure the wait and drain and re-fill time make the extra weight really important? Overall - economy requires everything be considered, not just the little problem of weight.)