Process and installation for the separation of heavy and light compounds by extraction using a supercritical fluid and nanofiltration
AssigneeCommissariat a l'Energie Atomique
InventorsStephane Sarrade, Maurice Carles, Christian Perre, Paul Vignet
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Abstract
A process and installation for the separation of heavy and light compounds is provided. According to the process, a solid or liquid phase containing the compounds to be separated is contacted with a supercritical fluid in an extractor, after which the supercritical fluid containing compounds leaving the extractor undergo nanofiltration for recovering a permeate flow containing the light compounds and a retentate flow containing the heavy compounds. The invention has particular utility for separating fats in food stuffs such as butter or fish oil.
Claims9
Process for separately recovering at least one light compound having a molecular weight from 50 to 1000 Daltons, and at least one heavy compound having a higher molecular weight than that of the light compound, from a solid or liquid phase containing both heavy and light compounds, comprising the steps in sequence of:
- a) contacting said solid or liquid phase with a supercritical fluid at a pressure P.sub.1 higher than the critical pressure P.sub.c of the fluid and at a temperature T.sub.1 higher than the critical temperature T.sub.c of said fluid whereby to produce a supercritical extraction-fluid containing heavy and light compounds,
- b) subjecting the supercritical extraction fluid of step a) to filtration through a nanofiltration membrane by directing said supercritical extraction fluid to one side of the membrane while applying to the other side of the membrane a pressure P.sub.2 lower than P.sub.1 and higher than P.sub.c, in order to separate the supercritical extraction-fluid into a light compound-depleted retentate flow and a permeate flow constituted by light compound-enriched supercritical fluid,
- c) recovering light compounds from the permeate flow, and
- d) recovering heavy compounds from the retentate flow.
Apparatus for separating at least one light compound having a molecule weight from 50 to 1000 Daltons, from at least one heavy compound having a higher molecular weight than that of the light compound, from a solid or liquid phase containing them, comprising:
- an extractor for receiving a solid or liquid phase containing the compounds to be extracted,
- a nanofiltration device having at least one nanofiltration membrane,
- pipes and pumps for circulating a supercritical fluid successively in the extractor and the nanofiltration device,
- a separator for recovering at the outlet from the nanofiltration device a permeate flow containing part of the extracted compounds and a retentate flow containing the other part of the extracted compounds,
- a separator for separating from the retentate flow the wholly or partly extracted products and for recycling into the extractor the supercritical fluid in the pure state or containing a residual part of the dissolved compounds,
- a separator for separating the extracted products from the permeate flow.
Dependencies are inferred from the claim text.