electrostatic treater interfce level control


Thread Starter

roberto arciniega

We have a Ktek Capacitance type level transmitter to measure the interface in a Electrostatic Treater and it is part of a LIC and LCV. We have rechecked its calibration and it is ok. In a current normal operation crude is flowing along with the water on the water line. That is the main problem.

I am not sure if the instrument is not working properly or we are not operating well.

Any ideas are quite welcome.

Asok Kumar Hait


Most probably the problem is with the level transmitter probe. I am working on a FPSO conversion project now. In a similar application of electrostatic treater our operation team also reported that the capacitance interface level transmitter didn't work at all. The reason they found is too much scaling on the probe. Later they installed a DP type level transmitter for the same application and it worked well. I am still investigating on this solution. The problem is if the density of the two liquids are close enough and there is chance of density variation then DP won't be reliable at all.
You must have an interface level gauge in the vessel. The transmitter reading is matching with the level gauge? You indicated that you have checked the calibration and that is OK. This confuses me. Did you check the complete physical calibration with the probe or just checked only the electronic calibration of the transmitter?

I will let you know if I could find further clue.

Asok Kumar Hait
We have had similar problems and we have finally come to the conclusion that the only proper I/F measuring instrument is the Guide Wave Radar since the Capacitance probe is to difficult to calibrate without any referencing instrument, particularly in a closed pressurized vessel.

The EST is a flooded vessel so that makes it different from the other vessels, so you need to calibrate the GWR in a slightly different manner. You need to switch off the I/F measurement and set it up like a normal level meter only. This sounds strange I know but it works since in a normal level application your wave will first go through air and then get to the water level. In this flooded application you need to modify the Di-electric constant in the service menu to tell the meter that is going through the oil first before it gets to the water. The DC of air is 1 so you need to change that in the service menu to about 3 for the DC of oil.

Di-electric constant of crude is anything from 1,8 to 4.