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IPSI Enhanced NGL Recovery
ProcessSM
(U.S. Patent No. 5,992,175 Issued 11/30/1999)
This recently patented process offers significant enhancements
to state-of-the-art NGL recovery processes. This process developed by IPSI utilizes a slip
stream from or near the bottom of the distillation column (demethanizer) as a mixed
refrigerant. The mixed refrigerant is totally or partially vaporized, providing
refrigeration for inlet gas cooling otherwise normally accomplished using a costly
external refrigeration system, including compressors, condensers, refrigerant
accumulators, economizers and refrigerant storage. The vapor generated from this
"self-refrigeration" cycle is specifically tailored to enhance separation
efficiency, then is recompressed and recycled back to the bottom of the tower where it
serves as a stripping gas. The innovation not only reduces or eliminates the need for
inlet gas cooling via external refrigeration, but also provides the following enhancements
to the demethanizer operation:
- Lowers the temperature profile in the tower, thereby permitting
better energy integration for inlet gas cooling via reboilers, resulting in reduced
heating and refrigeration requirements.
- Reduces and/or eliminates the need for external reboiler heat,
thereby saving fuel plus refrigeration.
- Enhances the relative volatility of the key components in the
tower when operated at a typical pressure, thereby improving separation efficiency and NGL
recovery; or alternatively allows increased tower pressure at a typical recovery
efficiency, thereby reducing the residue gas compression requirements.
It is noteworthy that the simplicity of the self-refrigeration
scheme can be adapted to most leading NGL recovery technologies to enhance the operational
efficiency and reduce capital and operating costs of those processes regardless of the
original licensor. Moreover, it can be configured into a simple add-on skid particularly
suitable for retrofitting plants to enhance NGL recovery and/or increase gas plant
capacity at original recovery levels without additional residue gas compression.
While the Process Enhancement scheme is widely applicable, it
offers significant advantages as applied to gas processing plants (existing or new) with
the following characteristics:
- The inlet gas is relatively rich in NGL’s and requires
refrigeration to obtain required liquid recoveries.
- Inlet gas pressure is in the intermediate to high ranges, (above
400 psi with the residue gas delivered at the same pressure as the inlet gas
- There is a benefit to maintaining recovery levels when the inlet
gas drops in pressure and/or becomes richer over time.
- There is an incentive to improve NGL recoveries in existing
plants by adding four or five pieces of equipment as a retrofit package.
- There is a need to process up to 20% more gas in an existing gas
plant without sacrificing NGL recovery levels or adding additional residue gas
compression. (This is by far the highest ROI achievable using this technology.)
IPSI offers this technology under license in
addition to industrial design and testing services.
(Click on image to enlarge.)
 Return to IPSI LLC Home Page
For more information please contact us at:
3000 Post Oak Boulevard
Houston, Texas 77056-6503
P.O. Box 2166
Houston, Texas 77252
Telephone: (713) 235-2400
Facsimile: (713) 235-1612
E-mail: delliot@bechtel.com
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