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US 7,955,506 B2Granted
Process for dewatering an aqueous organic solution
AssigneeChevron U.S.A. Inc.
InventorsPaul F. Bryan, Shabbir Husain, Prakhar Prakash
Life of this patent
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Abstract
An energy-efficient process for dewatering an aqueous organic solution includes using freely available solar energy to concentrate a draw solution within a reservoir. The draw solution is used in conjunction with a membrane to remove water from the organic solution in a forward osmosis process. The draw solution is diluted by the osmosis process, and returned to the reservoir to be re-concentrated and reused in the osmosis process.
Claims22
A system for dewatering an aqueous ethanol solution, comprising:
- a) a source of feed solution comprising ethanol and water, the feed solution having a water activity;
- b) a reservoir containing a draw solution comprising an osmotic agent selected from inorganic salts and acetate salts and water, the draw solution having a water activity lower than the water activity of the feed solution, wherein solar energy concentrates the draw solution to a desired concentration within the reservoir;
- c) a membrane having a water/ethanol selectivity greater than 4-50 and an osmotic agent rejection rate greater than 95%, the membrane having a draw solution side and a feed solution side;
- d) a means for delivering the feed solution to the feed solution side of the membrane whereupon the feed solution is dewatered;
- e) a means for delivering the draw solution from the reservoir to the draw solution side of the membrane whereupon the draw solution is diluted;
- f) a means for delivering the diluted draw solution from the draw solution side of the membrane to the reservoir;
- and
- g) a means for removing the dewatered ethanol solution from the feed solution side of the membrane.
5 more elements
A process for dewatering an aqueous ethanol solution, comprising the steps of:
- a) providing a membrane having a water/ethanol selectivity greater than 50 and an osmotic agent rejection rate greater than 95%, the membrane having a draw solution side and a feed solution side;
- b) delivering a feed solution comprising ethanol and water having a water activity to the feed solution side of the membrane;
- c) delivering a draw solution comprising an osmotic agent selected from inorganic salts and acetate salts having a water activity lower than the water activity of the feed solution and having a desired concentration from a reservoir to the draw solution side of the membrane whereupon water from the feed solution moves from the feed solution side of the membrane to the draw solution side of the membrane, thereby dewatering the feed solution and diluting the draw solution;
- d) delivering the diluted draw solution from the membrane to the reservoir;
- e) concentrating the draw solution in the reservoir by the use of solar energy to the desired concentration;
- and
- f) removing the dewatered ethanol solution from the membrane.
4 more elements
Dependencies are inferred from the claim text.