All unrefined crude oil stored in tanks has a percentage of water entrained within it, and while stored in tanks, separation naturally occurs with water collecting at the bottom of the tank beneath the oil. The two fluids are very distinct except for a "black water" or "rag" interface layer which is an emulsion of mixed oil and water.
Before the oil can be refined, a dewatering process must take place. To dewater the tank, water is drawn off of the bottom of the tank and is then sent off to water treatment. Once this is complete, the crude oil is ready for refining.
Magnetrol® has produced an applications brochure for the petroleum refining industry detailing measurement challenges and solutions for each step of the refining process. This blog post is part of an occasional series exploring each application in detail.
Level Measurement Challenges and Considerations
All level instruments used for crude oil dewatering must be capable of accurate interface level measurement. Level controls designed for interface detection will sense the beginning of the oil/water interface during dewatering procedures and provide feedback to a control system which will terminate water draw-off when appropriate.
Level Measurement Solutions
MAGNETROL has produced level measurement solutions for crude oil dewatering:
- Model A-15 displacer-actuated switch
- Eclipse® Model 706 guided wave radar transmitter
- E3 Modulevel® displacer-actuated transmitter
For more information on level measurement solutions for crude oil dewatering and other petroleum refining applications, download the petroleum refining brochure.