US3906250A
Expired / Lapsed
US
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Method and apparatus for generating power utilizing pressure-retarded-osmosis
Assignee: Ben Gurion University of the Negev Research and Development Authority Ltd
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Filing: 1974-06-19
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Granted: 1975-09-16
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Expires: 1994-06-19
Abstract
Abstract A method and apparatus are described for generating power by utilizing pressure-retarded-osmosis. A first liquid having a relatively high osmotic pressure is introduced at a relatively high hydraulic pressure into a first pathway in which it contacts one face of a semi-permeable membrane, and a second liquid having a lower osmotic pressure is introduced at a lower hydraulic pressure into a second pathway in which it contacts the opposite face of the membrane. At every point in the two pathways, the hydraulic pressure difference between the liquids on the opposite faces of the membrane is maintained at a value which is less than the osmotic pressure difference between the liquids. Part of the second liquid passes by pressure-retarded-osmosis through the semi-permeable membrane, forming a pressurized mixed solution of greater volume than that of the first liquid introduced into the first pathway. The potential energy stored in the pressurized mixed solution is then converted into useful energy, such as electrical or mechanical power. According to a further feature included in some of the described embodiments, after the potential energy stored in the pressurized mixed solution is converted into useful energy, the first and second liquids are recovered by separating from the mixed solution a quantity of the second liquid equal to the quantity which passed through the membrane, the original temperatures of the so-recovered first and second liquids are restored, the original hydraulic pressure difference is reapplied between the recovered first and second liquids, and the recovered first and second liquids are then recycled through the first and second pathways.
Inventors
- 👤 Sidney Loeb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:17
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/002; B01D61/0022; F; F03; F03G; F03G7/00; F03G7/008; F03G7/015
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
155 words
A method of generating power comprising: applying a hydraulic pressure to a first liquid of a first osmotic pressure and introducing same into a first pathway which is at least partially defined by one faCe of a semipermeable membrane; introducing a second liquid having a lower hydraulic pressure and a lower osmotic pressure into a second pathway which is at least partially defined by the opposite face of the membrane; maintaining the hydraulic pressure difference between liquids on the opposite faces of the membrane at a pressure difference which is less than the osmotic pressure difference between the liquids, at every point in the two pathways, thus effecting by PressureRetarded-Osmosis a passage of at least part of the second liquid through the semipermeable membrane, forming a pressurized mixed solution of greater volume than said first liquid introduced into said first pathway; and converting the potential energy stored in the pressurized mixed solution to useful energy.
Claim 2
Independent Claim
155 words
A method of generating power comprising: applying a hydraulic pressure to a first liquid of a first osmotic pressure and introducing same into a first pathway which is at least partially defined by one faCe of a semipermeable membrane; introducing a second liquid having a lower hydraulic pressure and a lower osmotic pressure into a second pathway which is at least partially defined by the opposite face of the membrane; maintaining the hydraulic pressure difference between liquids on the opposite faces of the membrane at a pressure difference which is less than the osmotic pressure difference between the liquids, at every point in the two pathways, thus effecting by PressureRetarded-Osmosis a passage of at least part of the second liquid through the semipermeable membrane, forming a pressurized mixed solution of greater volume than said first liquid introduced into said first pathway; and converting the potential energy stored in the pressurized mixed solution to useful energy.
Claim 3
Dependent Claim
26 words
The method according to claim 1, wherein said energy is converted by passing the increased-volume pressurized first liquid through a turbine generator to generate electrical power.
Claim 4
Dependent Claim
28 words
The method according to claim 1, wherein said first liquid is passed through the first pathway in counter-flow with respect to the second liquid in the second pathway.
Claim 5
Dependent Claim
20 words
The method according to claim 1, wherein the first and second liquids are saline water solutions having different osmotic pressures.
Claim 6
Dependent Claim
28 words
The method according to claim 4, wherein the first liquid is sea water and the second liquid is water having a lower concentration of salt than sea water.
Claim 7
Dependent Claim
31 words
The method according to claim 4, wherein the first liquid is a naturally available salt-water body, and the second liquid is derived from a river or ocean feeding the salt-water body.
Claim 8
Dependent Claim
29 words
The method according to claim 4, wherein the first liquid is a body of water to which salt has been artifically added to produce the higher osmotic pressure solution.
Claim 9
Dependent Claim
42 words
The method according to claim 1, wherein the first liquid is fed from an evaporation pond, and wherein the evaporation pond is fed from the outlet of the first pathway after the energy in the first liquid has been converted to power.
Claim 10
Dependent Claim
18 words
The method according to claim 8, including the further step of recovering the water evaporated from the pond.
Claim 11
Dependent Claim
26 words
The method according to claim 8, including the further step of recovering the concentrated solution and/or solutes resulting from the evaporation of water from the pond.
Claim 12
Dependent Claim
167 words
Apparatus for generating power from heat comprising: a semipermeable membrane; means for applying a hydraulic pressure to a first liquid of a first osmotic pressure and introducing same into a first pathway which is at least partially defined by one face of the semipermeable membrane; means for introducing a second liquid having a lower hydraulic pressure and a lower osmotic pressure into a second pathway which is at least partially defined by the opposite face of the membrane; means for maintaining the hydraulic pressure difference between liquids on the opposite faces of the membrane at a pressure difference which is less than the osmotic pressure difference between the liquids, at every point in the two pathways, thus effecting by Pressure-Retarded-Osmosis a passage of at least part of the second liquid through the semipermeable membrane, forming a pressurized mixed solution of greater volume than said first liquid introduced into said first pathway; and means for converting the potential energy stored in the pressurized mixed solution to useful energy.
Claim 13
Dependent Claim
167 words
Apparatus for generating power from heat comprising: a semipermeable membrane; means for applying a hydraulic pressure to a first liquid of a first osmotic pressure and introducing same into a first pathway which is at least partially defined by one face of the semipermeable membrane; means for introducing a second liquid having a lower hydraulic pressure and a lower osmotic pressure into a second pathway which is at least partially defined by the opposite face of the membrane; means for maintaining the hydraulic pressure difference between liquids on the opposite faces of the membrane at a pressure difference which is less than the osmotic pressure difference between the liquids, at every point in the two pathways, thus effecting by Pressure-Retarded-Osmosis a passage of at least part of the second liquid through the semipermeable membrane, forming a pressurized mixed solution of greater volume than said first liquid introduced into said first pathway; and means for converting the potential energy stored in the pressurized mixed solution to useful energy.
Claim 14
Dependent Claim
16 words
Apparatus according to claim 11, wherein said converting means comprises a turbine generator generating electrical power.
Claim 15
Dependent Claim
17 words
Apparatus according to claim 11, wherein said means for applying a hydraulic pressure comprises a liquid pump.
Claim 16
Dependent Claim
19 words
Apparatus according to claim 13, further including means for applying a portion of said energy to drive the pump.
Claim 17
Dependent Claim
59 words
Apparatus according to claim 11, further including an evaporation pond, means feeding the first liquid from the outlet end of the evaporation pond into the inlet end of the first pathway, and means feeding the first liquid from the outlet end Of the first pathway after passing through said conversion means into the inlet end of the evaporation pond.
Claim 18
Dependent Claim
33 words
A multi-stage system for generating power, each stage comprising apparatus of claim 11, the hydraulic pressure of the first liquid in the first stage being highest and progressively decreasing through all the stages.
Claim 19
Dependent Claim
84 words
The method of claim 1 including the further steps of: recovering the first and second liquids by separating from said mixed solution a quantity of second liquid substantially equal to the quantity which passed through the membrane and mixed with the first liquid; restoring substantially the original temperatures to the recovered first and second liquids; reapplying the above mentioned hydraulic pressure difference between the recovered first and second liquids; and recycling the recovered first and second liquids through the first and second pathways respectively.
Claim 20
Dependent Claim
20 words
The method according to claim 17, wherein the recovering of said first and second liquids is effected by thermal separation.
Claim 21
Dependent Claim
14 words
The method according to claim 18, wherein said thermal separation is effected by distillation.
Claim 22
Dependent Claim
32 words
The method according to claim 18, wherein said thermal separation is effected by using as said first and second liquids solutions of two liquid species whose miscibility is a function of temperature.
Claim 23
Dependent Claim
33 words
The method according to claim 18, wherein the thermal separation is effected by using as said first liquid a solution of a solvent and a solute whose solubility is a function of temperature.
Claim 24
Dependent Claim
20 words
The method according to claim 18, wherein said thermal separation is effected by using solar energy as the energy source.
Claim 25
Dependent Claim
97 words
A heat engine including the apparatus according to claim 11, further including: separating means for recovering the first and second liquids by separating from said mixed solution a quantity of second liquid substantially equal to the quantity which passed through the membrane and mixed with the first liquid; temperature restoral means for restoring substantially the original temperatures to the recovered first and second liquids; means for reapplying the above mentioned hydraulic pressure difference between the recovered first and second liquids; and means for recycling the recovered first and second liquids through the first and second pathways respectively.
Claim 26
Dependent Claim
18 words
The heat engine according to claim 23, wherein said separating means and temperature restoral means are thermal means.
Claim 27
Dependent Claim
16 words
The heat engine according to claim 24, wherein said thermal separating means comprises a distillation device.
Claim 28
Dependent Claim
31 words
The heat engine according to claim 25, wherein both said first and second liquids include dichlorodifluoromethane as the solvent, and the solute is a low molecular weight compound such as ethanol.
Claim 29
Dependent Claim
57 words
The heat engine according to claim 24, wherein the two liquids are solutions of two liquid species whose miscibility is a function of temperature, and wherein said thermal separating means comprises means for changing the temperature of the mixed solution, such that the mixed solution will separate into the first and second liquids thus substantially recovering them.
Claim 30
Dependent Claim
21 words
The heat engine according to claim 27, wherein one of the said liquid species is methanol and the other is hexane.
Claim 31
Dependent Claim
21 words
The heat engine according to claim 27, wherein one of the said liquid species is triethylamine, and the other is water.
Claim 32
Dependent Claim
43 words
The heat engine according to claim 24, wherein the first liquid is a solution of a solvent and a solute whose solubility is a function of temperature, and wherein said thermal separating means including means utilizing said latter property to precipitate the solute.
Claim 33
Dependent Claim
25 words
The heat engine according to claim 30, wherein said first liquid is a solution of water and potassium nitrate, and said second liquid is water.
References Cited (Backward Citations)
US3587227A
Cited
US3702532A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |