Crude Oil Stabiliser


Thread Starter

Steve Cordiner

We are in design stage and have a crude oil stabilser. Pro II shows that water cannot exist in hydrocarbons lower than tray 4. We have a nozzle on tray 4 which has a 6" line to a separator which is under interface control. The water is dumped to produced water tank and the hydrcarbons returned to the stabilser. my experience has only been on manual water draw. Any comments on interface control and how well this system will work?

Lewis Bodden

There are probes that can indicate the interface level and be tied into a level control scheme. The one's I've work with do not seem to have a problem. They do require periodic cleaning and re-calibration. I simple PI control works well. The integral should be kept to a minimum only to prevent a bias with Proportional only control.

Anand K. Iyer

difficult to answer with little info.
do you have interface level measurement. i.e., to know how much water is there.
is there a need to have some water (some interface level setpoint.
and so on.
Auto control of interface levels is possible.
The standard displacer float level column will work quite well in this application. I have used them successfully in several similar
applications in crude units, both through the DCS and with a field mounted pneumatic controller. Be sure to spec out the density of the hydrocarbon when ordering the displacer.

John Beck
Control System Specialist, Retired
Almeg Controls has an interface level transducer and point level probe that can either detect hydrocarbons or water. It does not need calibration and has output options of resistive, 3 wire voltage, or 4-20. Simply - the float can
be selected to float on either hydrocarbons or water. For your application - you may need two - one for hydrocarbons and one for water and read the difference. Follow the link for information - see the pdf file as well.

Thanks Bob Hogg