Patent US3661424A successfully refreshed from Google Patents.
US3661424A
Expired / Lapsed
US
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Geothermal energy recovery from deep caverns in salt deposits by means of air flow
Assignee: Akzo Nobel Salt Inc
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Filing: 1970-10-20
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Granted: 1972-05-09
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Expires: 1990-10-20
Abstract
Abstract There is disclosed a method for abstracting geothermal heat from depths below ground that are inaccessible by commercially practicable bore hole drilling techniques. More particularly, the invention is of a method for extracting heat from such an inaccessible source which comprises forming a cavern or reservoir at an accessible depth in a salt dome or spire which is in thermal communication with the otherwise inaccessible heat source, and flowing air at comparatively low speeds through the cavern in heat-exchange relation with the wall surfaces thereof to absorb heat therefrom, and then flowing it speedily through a relatively small (compared to the cavern volume) passageway to a point of use above ground, whereby it retains a substantial proportion of the heat energy absorbed in the cavern. Such energy is utilized in any suitable manner, one such preferred use being for the evaporation of brine extracted from the cavern during preparation thereof or obtained from neighboring salt deposits.
Inventors
- 👤 Charles H Jacoby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:28
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/28; E21B43/281; F; F24; F24T; F24T10/00; F24T10/20; Y; Y02; Y02E; Y02E10/00; Y02E10/10; Y10; Y10S; Y10S159/00; Y10S159/902
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
195 words
The method of extracting geothermal heat as a source of useful energy, at a desired rate from otherwise inaccessible depths below ground, which method comprises the steps of: a. locating a mineral formation of high heat conductivity extending vertically in thermal continuity from a deepseated heat source, said heat source being at a depth which is inaccessible by commercially practicable bore hole drilling techniques, and said formation extending to a level which is accessible by commercially practicable bore hole drilling techniques; b. establishing a heat well within said formation at an accessible depth within said mineral formation sufficient to assure that heat energy will flow from said source to said heat well so as to substantially constantly replenish heat extracted therefrom at said desired rate; c. flowing a comparatively cool gas through said heat well, whereby it acquires heat energy from the heat well at said desired rate without extracting the mineral defining the heat well; d. removing the heated gas from the heat well; e. transporting it to a point where its heat energy may be utilized; and f. utilizing the heat energy in the gas resulting from its contact with the heat well.
Claim 2
Independent Claim
195 words
The method of extracting geothermal heat as a source of useful energy, at a desired rate from otherwise inaccessible depths below ground, which method comprises the steps of: a. locating a mineral formation of high heat conductivity extending vertically in thermal continuity from a deepseated heat source, said heat source being at a depth which is inaccessible by commercially practicable bore hole drilling techniques, and said formation extending to a level which is accessible by commercially practicable bore hole drilling techniques; b. establishing a heat well within said formation at an accessible depth within said mineral formation sufficient to assure that heat energy will flow from said source to said heat well so as to substantially constantly replenish heat extracted therefrom at said desired rate; c. flowing a comparatively cool gas through said heat well, whereby it acquires heat energy from the heat well at said desired rate without extracting the mineral defining the heat well; d. removing the heated gas from the heat well; e. transporting it to a point where its heat energy may be utilized; and f. utilizing the heat energy in the gas resulting from its contact with the heat well.
Claim 3
Dependent Claim
49 words
A method according to claim 1 wherein said mineral formation of high heat conductivity is one which as been formed by fluid or plastic flow and vertical intrusion through surrounding rock formations of a portion of a deep-seated source of said mineral which is also the deep-seated heat source.
Claim 4
Dependent Claim
60 words
A method according to claim 2 wherein the mineral formation is a salt dome; the heat well is a cavern in the salt dome; the inaccessible heat source is a mother salt bed; the gas flowing through the cavern and removing heat from it is air, and the air is transported to the cavern and removed therefrom via bore hole(s).
Claim 5
Dependent Claim
80 words
A method according to claim 3 wherein the cavern in the salt dome is at a depth greater than 5,000 feet below the surface of the earth; the salt dome or spire is in communication with an inaccessible heat source at least 20,000 feet below the surface of the earth; the heated air is removed from the cavern by means of a bore hole passageway; and the volume of such passageway is substantially less than the volume of the cavern.
Claim 6
Dependent Claim
73 words
A method according to claim 4 wherein the cross-sectional area of the salt dome or spire below the level of said cavern is at least equal to the total surface area of the cavern; the cavern is of a volume of at least 1 million cubic feet; the temperature in the cavern is at least 200* F.; and the cross-sectional area of the bore hole exit passageway is at least 10 square inches.
Claim 7
Dependent Claim
120 words
A method according to claim 5 wherein the cavern is produced by solution mining of sodium chloride and is at a depth greater than 10,000 feet below the surface of the earth; the salt dome or spire is in communication with an inaccessible bed of salt comprising a heat source located at least 40,000 feet below the surface of the earth; the temperature in the cavern is maintained above 250* F. by control of the speed of extraction of heat energy by regulation of the air flow rate; the retention time of air in the cavern is at least one-half hour; and the retention time of air in the exit passageway in the bore hole is less than 5 minutes.
Claim 8
Dependent Claim
82 words
A method according to claim 6 wherein the retention time of air in the cavern is from 3 to 100 hours; the retention time of air in the exit passageway in the bore hole is from 5 seconds to 2 minutes; the volume of air flowing is from 20 to 5,000 cubic feet per second; the bore hole exit passageway is of 20 to 200 square inches cross-section; and heat recovery from the undErground heat source is from 1,000,000 to 50,000,000 B.t.u./hr.
Claim 9
Dependent Claim
21 words
A method according to claim 7 wherein the gas retention time in the exit passageway is from 5 to 30 seconds.
Claim 10
Dependent Claim
33 words
A method according to claim 8 wherein heat is extracted from the air during the concentration and/or evaporation of salt brine obtained from the salt deposit in which the cavern was solution mined.
Claim 11
Independent Claim
258 words
A method of extracting geothermal heat from a deep-seated heat source which is inaccessible by commercially practicable bore hole drilling techniques; which method comprises: flowing a comparatively cool gas through a cavern in a vertically extending mineral formation of high heat conductivity which is in thermal communication with said deep-seated heat source; removing the heated gas from the cavern and transporting it to a point where its heat energy may be utilized, and then utilizing the heat energy in the gas resulting from its dwell in the cavern; the cavern being at a depth greater than 5,000 feet below the surface of the earth and the inaccessible heat source being at least 20,000 feet below the surface of the earth; the thermal connection between the cavern and the inaccessible heat source being the vertically extending conductive mineral formation which is of a cross-sectional area at least equal to the cavern wall area; the heated gas being removed from the cavern by means of a bore hole exit passageway the volume of which is much less than the volume of the cavern; the cross-sectional area of the exit passageway being at least 10 square inches; the cavern volume being at least 1,000,000, cubic feet; the dwell of the heated gas in the exit passageway being less than 5 minutes; the dwell of the gas in the cavern being at least one-half hour; the temperature of the cavern being at least 250* F.; and the temperature of the gas exiting at the point of utilization being at least 180* F.
Claim 12
Independent Claim
258 words
A method of extracting geothermal heat from a deep-seated heat source which is inaccessible by commercially practicable bore hole drilling techniques; which method comprises: flowing a comparatively cool gas through a cavern in a vertically extending mineral formation of high heat conductivity which is in thermal communication with said deep-seated heat source; removing the heated gas from the cavern and transporting it to a point where its heat energy may be utilized, and then utilizing the heat energy in the gas resulting from its dwell in the cavern; the cavern being at a depth greater than 5,000 feet below the surface of the earth and the inaccessible heat source being at least 20,000 feet below the surface of the earth; the thermal connection between the cavern and the inaccessible heat source being the vertically extending conductive mineral formation which is of a cross-sectional area at least equal to the cavern wall area; the heated gas being removed from the cavern by means of a bore hole exit passageway the volume of which is much less than the volume of the cavern; the cross-sectional area of the exit passageway being at least 10 square inches; the cavern volume being at least 1,000,000, cubic feet; the dwell of the heated gas in the exit passageway being less than 5 minutes; the dwell of the gas in the cavern being at least one-half hour; the temperature of the cavern being at least 250* F.; and the temperature of the gas exiting at the point of utilization being at least 180* F.
Claim 13
Dependent Claim
161 words
A method according to claim 10 wherein the deep-seated heat source is a mother salt bed; the vertically extending mineral formation is a salt dome or spire; the comparatively cool gas circulated through the cavern is air; the cavern is at a depth greater than 10,000 feet; the mother salt bed is at a depth greater than 40,000 feet; the cross-sectional area of the exit passageway is at least 25 square inches; the dwell of the air in the exit passageway is from 5 to 30 seconds; the dwell of the air in the cavern is from 3 to 100 hours; the air is moved speedily through the exit passageway; the temperature of the air exiting at the point of utilization is at least 220* F.; and the temperature of the air leaving the cavern is maintained above 250* F. by control of the speed of extraction of heat energy from the cavern by regulation of the rate of air flow.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |