After the hydrates are removed from natural gas, the next step in processing is natural gas liquid, or NGL, recovery. Separating the hydrocarbons and fluids from pure natural gas produces pipeline quality dry natural gas. It also ensures that valuable byproducts like propane and butane can be processed and sold as well. These products are not pipeline quality while part of the natural gas, but with processing and recovery, they can become more valuable than they were as part of the natural gas stream.
The two principle techniques for removing NGLs are the absorption method and the cryogenic expander method. The absorption method is very similar to the gas dehydration process, except that absorbing oil is used, rather than glycol. The cryogenic expander method involves low-temperature distillation and expanding the gas in a turbo-expander. Regardless of the method used to remove them, once NGLs have been removed from the natural gas stream, they must be separated out, or fractionated.
This post in the Magnetrol® blog series on natural gas processing explores level measurement challenges and solutions for the NGL recovery and storage process.
Level Measurement Challenges and Considerations
Absorption method level control is typically found on flash drums, separation towers and reflux systems. Cryogenic method level control is applied to the separator and dehydrator. In each instance, the most reliable and accurate level instrumentation is needed in order to facilitate NGL recovery and prevent NGLs from remaining in the natural gas stream.
Level Measurement Solutions
MAGNETROL has produced level measurement solutions for NGL recovery and storage:
- For point level:
Echotel® Model 961 ultrasonic gap switch or Thermatel® Model TD1/TD2 thermal dispersion switch
- For continuous level:
Eclipse® Model 706 guided wave radar transmitter or E3 Modulevel® displacer transmitter
- For visual indication:
Atlas or Aurora® magnetic level indicators
For more information about level measurement solutions for NGL recovery and storage, or other natural gas processing applications, download the natural gas processing brochure.