After crude oil has been desalted, dewatered and gone through the distillation process, the next step is reflux. A heat exchanger removes vapor from the upper parts of the fractionator, cools it to a liquid, and pumps it into an accumulator, also known as a reflux drum. Reflux pumps then draw liquid from the bottom of the accumulator and pump part of it back, where it is reintroduced at a lower point in the column.
This refluxing process improves separation in the column by assuring sufficient downward liquid flow meeting the rising vapor. Reflux accumulators are essential to increase the efficiency of distillation columns.
Magnetrol® has produced an applications brochure for the petroleum refining industry detailing level measurement challenges and solutions for each step of the refining process. This blog is part of an occasional series exploring each application in detail.
Level Measurement Challenges and Considerations
Accurate and reliable level monitoring and control is necessary for the reflux accumulator to serve as a distribution point for reflux and distillate, and prevent excessive reflux from returning back to the tower. Reflux accumulators must be monitored using instruments that can detect level precisely and consistently. In addition, better level measurement of reflux accumulators can make the distillation process more efficient.
Level Measurement Solutions
MAGNETROL has produced accurate, reliable level measurement solutions for reflux accumulators:
- For point level
Series 3 float-actuated external cage level switch
- For continuous level
Eclipse® Model 706 guided wave radar or E3 Modulevel® displacer-actuated transmitter
- For visual indication
Atlas™ or Aurora® magnetic level indicators can be supplied with switches or transmitters
For more information on level measurement solutions for reflux accumulators and other petroleum refining applications, download the petroleum refining brochure.