Solvent extraction process involving membrane separation of extract phase and/or intermediate zone phase with pseudo extract/pseudo raffinate recycle, preferably employing interfacially polymerized membranes
US5234597A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1991 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Jul 18, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10G31/11
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The solvent extraction of aromatics containing oil using a selective aromatics extraction solvent to produce an aromatics rich extract phase and an oil rich/aromatics lean raffinate is improved by the steps of subjecting the extract phase to a membrane separation step to produce a permeate phase and a retentate phase passing the retentate phase to a settling zone wherein the retentate phase spontaneously separates into two liquid phases, and recycling the upper phase to the extraction zone, either to the feed inlet or to the bottom of the extract reflux zone to thereby increase the raffinate oil recovered from the extraction tower. Alternatively or in addition to the above, a side stream can be taken from an intermediate zone of the extraction zone (e.g. extraction tower) and fed to a membrane separation to produce a solvent rich permeate and an oil rich retentate. The solvent rich permeate is recycled while the oil rich retentate is fed to a settling zone wherein it will spontaneously separate into an oil rich pseudo raffinate upper phase which is recovered and into a solvent rich pseudo extract bottoms phase which is recycled to the solvent extraction zone, preferably at a point …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.