US3757516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Geothermal energy system
Assignee: Magma Power Co
•
Filing: 1971-09-14
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Granted: 1973-09-11
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Expires: 1991-09-14
Abstract
Abstract Method and apparatus for the nonpolluting generation of electrical power by the economic utilization of geothermal energy that is accessible through widespread sources of regenerative geothermal hot water. A well provides access to a geothermal hot water source having a temperature substantially above the flash point for atmospheric pressure, this hot water being conducted through heat exchangers wherein its heat energy is transferred to a power fluid employed in a closed Rankine heat engine cycle to generate electrical power, the water then being injected back into the aquifer. The geothermal hot water is pressurized by deep well pump means to a discharge pressure above its saturated vapor pressure for the source temperature, and a pressure gradient above the saturated vapor pressure is maintained through the heat exchangers, whereby the hot water is restrained from flashing into steam throughout its circuit, thereby avoiding any substantial temperature drop between the source and the heat exchangers and preventing release of any substantial mineral deposits at any point in the circuit. The very small expenditure of power required for such pressurization produces a large increase in total plant power output and efficiency by, among other things, (1) providing a top temperature power fluid Rankine cycle, (2) avoiding fouling of the well and surface equipment with mineral deposits, (3) deriving power from all of the geothermal fluid rather than just a stream fraction thereof, (4) allowing use of a power fluid that is particularly efficient in the available temperature range, and (5) avoiding degeneration of the power fluid source and ecological damage by returning the geothermal fluid to the aquifer.
Inventors
- 👤 Cabe B Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:39
CPC Classifications
F; F01; F01K; F01K25/00; F01K25/08; F01K7/00; F03; F03G; F03G4/00; F03G4/074; F24; F24T; F24T10/00; F24T10/20; Y; Y02; Y02E; Y02E10/00; Y02E10/10; Y10; Y10S; Y10S166/00; Y10S166/902
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
154 words
The method of generating electrical power from geothermal energy which comprises providing access through a well to an underground source of geothermal hot water having a temperature substantially above the flash point for atmospheric pressure, conducting a stream of said geothermal hot water from said source to an upper position remote from said source and placing said hot water into heat exchange relationship with a power fluid that is employed in a closed (Rankine) heat engine cycle to drive electric generator means, transferring the heat energy contained in said geothermal hot water to said power fluid in said heat exchange relationship, and restraining said geothermal hot water in said stream from flashing into steam from said source through said heat exchange relationship so as to transfer the heat energy from said geothermal hot water to said power fluid in a maximum Rankine cycle temperature range and to prevent mineral precipitation from said geothermal water.
Claim 2
Independent Claim
154 words
The method of generating electrical power from geothermal energy which comprises providing access through a well to an underground source of geothermal hot water having a temperature substantially above the flash point for atmospheric pressure, conducting a stream of said geothermal hot water from said source to an upper position remote from said source and placing said hot water into heat exchange relationship with a power fluid that is employed in a closed (Rankine) heat engine cycle to drive electric generator means, transferring the heat energy contained in said geothermal hot water to said power fluid in said heat exchange relationship, and restraining said geothermal hot water in said stream from flashing into steam from said source through said heat exchange relationship so as to transfer the heat energy from said geothermal hot water to said power fluid in a maximum Rankine cycle temperature range and to prevent mineral precipitation from said geothermal water.
Claim 3
Dependent Claim
61 words
The method of claim 1, wherein said stream of geothermal hot water is restrained from flashing into steam by pressurization thereof proximate said source to a well discharge pressure above the saturated vapor pressure of the geothermal water for the source temperature, and maintaining a pressure gradient above the saturated vapor pressure of the geothermal water through said heat exchange relationship.
Claim 4
Dependent Claim
39 words
The method of claim 2, wherein said pressurization of said stream proximate said source is to a well discharge pressure at least about 1 1/2 times the absolute saturated vapor pressure of the geothermal water for the source temperature.
Claim 5
Dependent Claim
32 words
The method of claim 3, wherein said pressure gradient is also maintained at least about 1 1/2 times the absolute saturated vapor pressure of the geothermal water through said heat exchange relationship.
Claim 6
Dependent Claim
22 words
The method of claim 2, wherein said pressurization is effected by deep well pump means proximate said source of geothermal hot water.
Claim 7
Dependent Claim
23 words
The method of claim 5, wherein said deep well pump means is driven by electrical power derived from said Rankine heat engine cycle.
Claim 8
Dependent Claim
51 words
The method of claim 5, wherein said deep well pump means is located at a sufficient depth in the well so that the geothermal hot water received by said pump means will be at a pressure greater than the saturated vapor pressure for the geothermal hot water at its received temperature.
Claim 9
Dependent Claim
39 words
The method of claim 7, wherein said depth is reduced by application of gas pressure through the well to the underground geothermal system so as to increase the pressure on the geothermal hot water source proximate the pump means.
Claim 10
Dependent Claim
21 words
The method of claim 1, wherein said temperature of said source of geothermal hot water is at least about 240* F.
Claim 11
Dependent Claim
21 words
The method of claim 1, wherein said temperature of said source of geothermal hot water is at least about 300* F.
Claim 12
Dependent Claim
11 words
The method of claim 1, wherein said power fluid is isobutane.
Claim 13
Dependent Claim
50 words
The method of claim 1, wherein the body of said geothermal hot water that is conducted from said source is conducted back into the underground geothermal system from which it was derived after passing through said heat exchange relationship, so as to preserve the natural mineral balance of the system.
Claim 14
Dependent Claim
94 words
The method of claim 1, wherein said stream of geothermal hot water and said power fluid have a counterflow heat exchange relationship through three stages, a first stage wherein the power fluid is preheated in a liquid-to-liquid heat exchange relationship, a second stage wherein the power fluid is vaporized in a liquid-to-liquid and gas heat exchange relationship, and a third stage wherein the power fluid is superheated in a liquid-to-gas heat exchange relationship, the majority of the heat energy transfer from said geothermal hot water to said power fluid occurring in said first stage.
Claim 15
Dependent Claim
93 words
The method of claim 1, wherein said stream of geothermal hot water is conducted into heat exchange relationship with a plurality of different power fluids employed in a plurality of respective closed Rankine heat engine cycle to drive said electric generator means, a portion of the heat energy contained in said geothermal hot water being transferred to each of said power fluids, the portion of said heat energy transferred to one of said power fluids being transferred in a relatively higher temperature range than the portion transferred to another of said power fluids.
Claim 16
Dependent Claim
61 words
The method of claim 1, wherein at least a portion of the body of geothermal hot water that has passed through said heat exchange relationship in injected back into said well so as to reduce the average temperature in the well and thereby reduce the well pressure required to prevent the geothermal hot water in said stream from flashing into steam.
Claim 17
Dependent Claim
20 words
The method of claim 15, wherein said temperature of said source of geothermal hot water is above about 400* F.
Claim 18
Independent Claim
254 words
A system for generating electrical power from geothermal energy which comprises: a well providing access from the ground-level surface to an underground geothermal hot water source having a temperature substantially above the flash point from atmospheric pressure; conduit means communicating with said source to receive a stream of geothermal hot water therefrom and extending through said well to apparatus positioned adjacent said surface, said apparatus including electric generator means, Rankine cycle heat engine means drivingly connected to said generator means and including closed power fluid circuit means, heat exchanger means connected to said conduit means and to said power fluid circuit means and arranged to dispose said stream of geothermal hot water in heat exchange relationship with said power fluid so as to transfer the heat energy contained in said geothermal hot water to said power fluid; and pump means operatively associated with said conduit means pressurizing said stream to a well discharge pressure above the saturated vapor pressure of the geothermal water for the source temperature and maintaining a pressure gradient in said conduit means and in said heat exchanger means above the saturated vapor pressure of the geothermal water so as to restrain said geothermal hot water of said stream from flashing into steam from said source through said heat exchanger relationship, thereby transferring the heat energy from said geothermal hot water to said power fluid in a maximum Rankine cycle temperature range and preventing mineral precipitation from the geothermal hot water in said conduit means and in said heat exchanger means.
Claim 19
Independent Claim
254 words
A system for generating electrical power from geothermal energy which comprises: a well providing access from the ground-level surface to an underground geothermal hot water source having a temperature substantially above the flash point from atmospheric pressure; conduit means communicating with said source to receive a stream of geothermal hot water therefrom and extending through said well to apparatus positioned adjacent said surface, said apparatus including electric generator means, Rankine cycle heat engine means drivingly connected to said generator means and including closed power fluid circuit means, heat exchanger means connected to said conduit means and to said power fluid circuit means and arranged to dispose said stream of geothermal hot water in heat exchange relationship with said power fluid so as to transfer the heat energy contained in said geothermal hot water to said power fluid; and pump means operatively associated with said conduit means pressurizing said stream to a well discharge pressure above the saturated vapor pressure of the geothermal water for the source temperature and maintaining a pressure gradient in said conduit means and in said heat exchanger means above the saturated vapor pressure of the geothermal water so as to restrain said geothermal hot water of said stream from flashing into steam from said source through said heat exchanger relationship, thereby transferring the heat energy from said geothermal hot water to said power fluid in a maximum Rankine cycle temperature range and preventing mineral precipitation from the geothermal hot water in said conduit means and in said heat exchanger means.
Claim 20
Dependent Claim
41 words
A system as defined in claim 17, wherein said pump means is adapted to pressurize said stream to a well discharge pressure at least about 1 1/2 times the absolute saturated vapor pressure of the geothermal water for the source temperature.
Claim 21
Dependent Claim
27 words
A system as defined in claim 18, wherein said pressure gradient is at least about 1 1/2 times the absolute saturated vapor pressure of the geothermal water.
Claim 22
Dependent Claim
23 words
A system as defined in claim 17, wherein said pump means includes a deep well pump disposed proximate said source of geothermal water.
Claim 23
Dependent Claim
22 words
A system as defined in claim 20, wherein said deep well pump is driven by electrical power derived from said generator means.
Claim 24
Dependent Claim
52 words
A system as defined in claim 20, wherein said deep well pump is located at a sufficient depth in the well so that the geothermal hot water received by said pump means will be at a pressure greater than the saturated vapor pressure for the geothermal hot water at its received temperature.
Claim 25
Dependent Claim
23 words
A system as defined in claim 17, wherein said temperature of said source of geothermal hot water is at least about 240* F.
Claim 26
Dependent Claim
23 words
A system as defined in claim 17, wherein said temperature of said source of geothermal hot water is at least about 300* F.
Claim 27
Dependent Claim
13 words
A system as defined in claim 17, wherein said power fluid is isobutane.
Claim 28
Dependent Claim
75 words
A system as defined in claim 17, which includes injection well means spaced from said well, said injection well means communicating with the underground geothermal system from which said geothermal hot water was derived and having sufficient capacIty to accommodate the entire flow of said stream, and return conduit means extending from said heat exchanger means to said injection well means for returning said stream of geothermal hot water back into said underground geothermal system.
Claim 29
Dependent Claim
28 words
A system as defined in claim 26, which includes throttle valve means in said return conduit means permitting control of said pressure gradient in said heat exchanger means.
Claim 30
Dependent Claim
83 words
A system as defined in claim 17, which includes reinjection conduit means extending from said heat exchanger means to said well externally of said conduit means, said reinjection conduit means conducting at least a portion of the body of hot water that has passed through said heat exchanger means back into the well so as to reduce the average temperature in the well and thereby reduce the well pressure required to prevent the geothermal hot water in said stream from flashing into steam.
Claim 31
Dependent Claim
36 words
A system as defined in claim 28, which includes valve means operatively associated with said reinjection conduit means and selectively operable to divert a controlled proportion of said body of hot water back into the well.
Claim 32
Dependent Claim
22 words
A system as defined in claim 28, wherein said temperature of said source of geothermal hot water is above about 400* F.
Claim 33
Dependent Claim
98 words
A process for converting naturally occurring heat energy carried by water from an underground geothermal well source to mechanical energy comprising the steps of: conducting a stream of said water from said source to an upper position remote from said source and passing said water in heat exchange relationship with an operating fluid having a critical temperature below the input temperature of the water; superheating the operating fluid with head from the water; expanding the operating fluid in a power extracting gas expansion device; condensing the operating fluid after expansion; and repeating the steps in a continuous process.
Claim 34
Dependent Claim
98 words
A process for converting naturally occurring heat energy carried by water from an underground geothermal well source to mechanical energy comprising the steps of: conducting a stream of said water from said source to an upper position remote from said source and passing said water in heat exchange relationship with an operating fluid having a critical temperature below the input temperature of the water; superheating the operating fluid with head from the water; expanding the operating fluid in a power extracting gas expansion device; condensing the operating fluid after expansion; and repeating the steps in a continuous process.
Claim 35
Dependent Claim
37 words
A process in accordance with claim 31 wherein the operating fluid is condensible at the output pressure of the gas expansion device in a heat exchanger with cooling fluid from a cooling tower operating at atmospheric conditions.
Claim 36
Dependent Claim
21 words
A process in accordance with claim 31 wherein the operating fluid has a boiling point below the boiling point of water.
Claim 37
Dependent Claim
15 words
A process in accordance with claim 31 wherein the operating fluid is a pure substance.
Claim 38
Dependent Claim
13 words
A process in accordance with claim 34 wherein the operating fluid is isobutane.
Claim 39
Dependent Claim
102 words
A process for converting heat energy carried by a hot fluid to mechanical energy comprising the steps of: passing hot fluid heated by heat energy within the earth from an underground source to a first upper position remote from said source and placing said hot fluid into heat exchange relationship with an operating fluid having a critical temperature below the input temperature of the hot fluid; superheating the operating fluid with the heat from the hot fluid; expanding the operating fluid in a power extraction gas expansion device; condensing the operating fluid after extraction; and repeating the steps in a continuous process.
Claim 40
Dependent Claim
102 words
A process for converting heat energy carried by a hot fluid to mechanical energy comprising the steps of: passing hot fluid heated by heat energy within the earth from an underground source to a first upper position remote from said source and placing said hot fluid into heat exchange relationship with an operating fluid having a critical temperature below the input temperature of the hot fluid; superheating the operating fluid with the heat from the hot fluid; expanding the operating fluid in a power extraction gas expansion device; condensing the operating fluid after extraction; and repeating the steps in a continuous process.
Claim 41
Dependent Claim
34 words
A process in accordance with claim 36 comprising the further steps of raising the temperature of the operating fluid to where the operating fluid has sufficient superheat to avoid condensation in a prime mover.
Claim 42
Dependent Claim
37 words
A process in accordance with claim 36 wherein the operating fluid is condensible at the output pressure of the gas expansion device in a heat exchanger with cooling fluid from a cooling tower operating at atmospheric conditions.
Claim 43
Dependent Claim
194 words
A process for converting heat energy carried by a hot fluid to mechanical energy comprising the steps of: in the first system, passing hot fluid heated by heat energy within the earth from an underground source to an upper position remote from said source and placing said hot fluid into heat exchange relationship with a first operating fluid having a critical temperature below the input temperature of The hot fluid; superheating the operating fluid with the heat from the hot fluid; expanding the operating fluid in a power extracting gas expansion device; condensing the operating fluid after expansion; repeating the steps in a continuous process; and in a second system, passing at least a portion of the hot fluid in heat exchange relationship with a second operating fluid having a critical temperature below the temperature of the hot fluid after the hot fluid has passed in heat exchange relationship with the first operating fluid; superheating the second operating fluid with the heat remaining in the hot fluid; expanding the second operating fluid in a power extracting gas expansion device; condensing the second operating fluid after expansion; and repeating the steps in a continuous process.
Claim 44
Dependent Claim
194 words
A process for converting heat energy carried by a hot fluid to mechanical energy comprising the steps of: in the first system, passing hot fluid heated by heat energy within the earth from an underground source to an upper position remote from said source and placing said hot fluid into heat exchange relationship with a first operating fluid having a critical temperature below the input temperature of The hot fluid; superheating the operating fluid with the heat from the hot fluid; expanding the operating fluid in a power extracting gas expansion device; condensing the operating fluid after expansion; repeating the steps in a continuous process; and in a second system, passing at least a portion of the hot fluid in heat exchange relationship with a second operating fluid having a critical temperature below the temperature of the hot fluid after the hot fluid has passed in heat exchange relationship with the first operating fluid; superheating the second operating fluid with the heat remaining in the hot fluid; expanding the second operating fluid in a power extracting gas expansion device; condensing the second operating fluid after expansion; and repeating the steps in a continuous process.
Claim 45
Dependent Claim
16 words
A process in accordance with claim 39 wherein the first operating fluid is a pure substance.
Claim 46
Dependent Claim
14 words
A process in accordance with claim 40 wherein the first operating fluid is isobutane.
Claim 47
Dependent Claim
21 words
A process in accordance with claim 39 wherein the first operating fluid is isobutane and the second operating fluid is freon.
References Cited (Backward Citations)
CH135306A
Cited
US2593963A
Cited
US3140986A
Cited
US3274769A
Cited
US3470943A
Cited
US3605403A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |