US 7,608,188 B2Granted

Vacuum enhanced direct contact membrane distillation

AssigneeBoard of Regents of the Nevada System of Higher Education

InventorsTzahi Y. Cath, V. Dean Adams, Amy E. Childress

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Abstract

The present disclosure provides methods and systems for purifying an impaired liquid. In a particular example, the disclosure provides methods and systems for purifying water containing a solute. A feed stream of solute containing water is introduced in a flow chamber. A permeate stream of water at least substantially free of the solute is placed in the flow chamber. A hydrophobic membrane is placed between the feed stream and the permeate stream. A vacuum is applied to the permeate stream. A vapor pressure differential causes water to vaporize from the feed stream, pass through the hydrophobic membrane, and condense in the permeate stream.

Claims23

Dependent claims

A liquid extraction system comprising:

a feed source configured to supply a feed stream having a first pressure and comprising a solvent;
a permeate source comprising an inlet and a fluid at a second pressure and configured to supply a permeate stream;
a flow cell comprising a feed inlet, a feed outlet, a permeate inlet, a permeate outlet, and
a membrane, the flow cell coupled to the feed source and the permeate source such that the membrane is intermediate, and may be placed in contact with, the feed and permeate streams;
a flow pump in communication with the feed source, whereby the flow pump causes the feed stream to flow on the membrane;
a vacuum pump operatively coupled to the permeate outlet of the flow cell and to the inlet of the permeate source, whereby the vacuum pump draws a vacuum on the permeate stream and the permeate side of the flow cell, causing permeate to flow from the permeate source, though the permeate inlet of the flow cell into the flow cell, and from the permeate outlet of the flow cell back into the permeate source;
whereby a partial vapor pressure differential is induced across the membrane by a temperature differential between the feed and permeate streams and a differential between the first and second pressures, causing solvent to evaporate from the feed stream, pass through the membrane, and condense in the permeate stream flowing through the flow cell.

4 more elements

An extraction system comprising:

(A) a feed cycle configured to supply a feed stream comprising a solvent at a first temperature and a first pressure, the feed cycle comprising
(i) a feed source;
(ii) a feed cycle flow pump in communication with the feed source;
(iii) a feed stream temperature gauge, wherein the feed stream temperature gauge may be placed in communication with the feed stream;
(iv) a feed stream flow meter, wherein the feed stream flow meter may be placed in communication with the feed stream;
(B) a permeate cycle configured to supply a permeate stream at a second temperature and a second pressure, the second temperature being lower than the first temperature, the permeate cycle comprising:
(i) a permeate source comprising an inlet and an outlet;
(ii) a permeate cycle vacuum pump comprising an inlet and an outlet, the permeate cycle vacuum pump outlet operatively coupled to the inlet of the permeate source, the permeate cycle vacuum pump configured to draw a vacuum on the permeate stream, causing the second pressure to be lower than the first pressure;
(iii) a permeate stream temperature gauge, wherein the permeate stream temperature gauge may be placed in communication with the permeate stream;
(iv) a permeate stream flow meter, wherein the permeate stream flow meter may be placed in communication with the permeate stream;
(v) a permeate stream pressure gauge;
and
(C) a flow cell, the flow cell comprising:
(i) a permeate side comprising a permeate inlet and a permeate outlet, the permeate outlet in fluid communication with the inlet of the permeate cycle vacuum pump, the permeate inlet operatively coupled to the outlet of the permeate source and configured to transmit the permeate stream into the permeate side of the flow cell;
(ii) a feed side comprising a feed inlet, the feed inlet in fluid communication with the feed source and configured to transmit the feed stream into the feed side of the flow cell;
(iii) a membrane interposed between the permeate side and the feed side and configured to be contacted with the feed stream and the permeate stream;
whereby a partial pressure differential is induced across the membrane by the differentials between the first and second temperatures and the first and second pressures, causing solvent to evaporate from the feed stream, pass through the membrane, and condense in the permeate stream.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/293,407Filed 2 Dec 2005 · us provisional application
Priority: 3 Dec 2004
Published: US 2006/0144788 A16 Jul 2006
Granted: 27 Oct 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

B01D 61/364
Pervaporation; Membrane distillation; Liquid permeation: membrane distillation
C02F 1/447
By dialysis, osmosis or reverse osmosis: by membrane distillation
B01D
Separation
C02F
Treatment of water, waste water, sewage, or sludge

Family

Application60/633,334Us provisional application · filed 3 Dec 2004
US 2006/0144788 A1Pre-grant publication · published 6 Jul 2006
US 7,608,188 B2This patent

From the US filing history. Foreign family members aren’t listed.

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