Oil Water Interface

Dear Jose John

I reccomend you to use Interface Detectors made by Agar Corporation (www.agarcorp.com). This is the only instrument than can give you a precise measurement of your oil/water interface level.

David Rodrigues

That is right for that instrument only in case of clearly separation between oil and water. But in case of emulsion, the reading will be false. I faced a lot of problems related to that aspect during commissioning/startup of 3-phase separators (test & production) designed by us. I recommend using of both instruments: Interface Level Switch and Level Glass.

a sight glass might help. A dye that is water soluble, say an ionic dye, that is not soluble in oil may also help give more contrast, but you would need to add some from time to time as water is drained.

I assume you drain the water from the bottom with an open topped tube to the water drain so no oil get ou and you want to make sure no oil gets out.

So a 10 foot tank full to 10 feet with water will have about 5 PSI at the bottom via pressure gage. If it was full of oil with a density of 0.65 the bottom pressure would be 5 x 0.65 = 3.25 PSI

You can now make a chart of level versus bottom pressure with a gage. As the oil layer gets deeper the bottom pressure will drop and you might set 4 psi as your lowest level to give some safety margin. A less deep tank would be similar.

A manometer on the wall of the tank with a colored fluid in it can be used as a guide.

Given calm conditions, oil and water separate into two layers, with the water layer being on the bottom.

Oil, being non-conductive, doesn't respond to conductivity sensors.

Does that help?

Clear glass, or rigid plastic tube, finger firmly closing one end, and use it as a dip-stick, withdraw it up, after momentarily releasing finger pressure to allow liquid to enter the tube. It needs to be very small ID so that the entrapped liquid stays in the tube when withdrawn. The oil mark on the outside of the tube, measure down to the water 'layer', and there you have it. I guess it's a bit like a liquid 'core drill'. The size of the tube I'm thinking of is like that of ball-point pen refill, so that the surface tension retains the water in the tube ( along with your finger over the other end).

See how you go,

Cheers

Stu

josej,

While an electronic oil-water interface meter is the more precise way to go, there are other, considerably more economical options, especially if the tank is either open-topped, or can be accessed with a dipstick.

There are water or petroleum activated pastes that can be applied to the side of a calibrated dipstick, which when inserted into the liquid filled tank, will change color, showing the thickness of the floating oil layer, and the underlying water.

I've used pastes made by Kolor Kut, as well as McCabe. One comes in squeeze tubes, the other in small jars. (I haven't used this stuff in 8 or 10 years, but it is still on the market.)

You can check out some descriptive info at:

http://www.channelsupplies.com/paste.htm

And here's a link to the supplier I used to purchase this stuff from:

http://www.benmeadows.com/search/kolor+kut/20992/

================================================================

Just my $0.02...

one can try with Endress and Hauser (GWR) model with single axial probe

regards

find2am

Dear companions,

I am facing the same problem, but in my case there is a Dysplacer Level measurement that, unfortunately, does not work fine. In part, I believe that the instrument was wrong installed. The Stand-Pipe where the instrument is connected has just two connections to the Separator Vessel (in the top and the bottom), and I believe that the correct way to connect this instrument, for this application, is with three connections (top, middle and bottom of the Vessel), because this way the gas, oil, emulsion and water will be present in the stand-pipe, giving the best representation of vessel conditions. Please, am I wrong?

I was looking for something like GWR too, and/or Capacitive Level measurement. What do you thing about it? What is the best technology in this case?

Hello,

I think you can use oil water interface meter for real time measuring.

If you need a continuous monitoring you should contact us and we'll try to find solution.