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US3782468A
Expired / Lapsed
US
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Geothermal hot water recovery process and system
Assignee: ROGERS ENG CO Inc
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Filing: 1971-09-20
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Granted: 1974-01-01
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Expires: 1991-09-20
Abstract
Abstract An improved process and system for recovering high temperature hot water from a geothermal supply. A well casing assembly is sunk to position an apertured end portion of a casing in proximity to an underground hot water supply with an apertured end portion of a centrally disposed conduit within the casing adjacent the apertured casing end. By reducing the pressure at the well head, flashing of the hot water to steam occurs to elevate a two phase mixture of steam and hot water through the casing assembly. Such flashing is accompanied by the evolution of substantially non-condensible gases, including carbon dioxide. Such gases are separated with the steam from the elevated hot water, the latter being withdrawn from the system for its intended use, such as the generation of electric power. The separated steam and gases are heat exchanged to condense the steam and to withdraw useful heat from the gases, following which the gases are compressed and recycled into contact with the underground hot water supply to assist in elevating additional hot water. The carbon dioxide containing gases are effective in countering the problems normally created when geothermal hot water is allowed to flash to steam, namely the formation of system clogging deposits, of which calcium carbonate and magnesium hydroxide are typical, within the well and related apparatus. The presence of carbon dioxide in the recycled gases during the steam flashing maintains chemical equilibrium in the system to prevent formation of such deposits. Thus, without utilizing mechanical or other pumping devices within the well, recovery of a substantially constant stream of geothermal hot water from a deep underground well may be effected without attendant precipitation of clogging chemical compounds commonly encountered when geothermal hot water is elevated utilizing a steam flashing procedure.
Inventors
- 👤 J Kuwada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:09
CPC Classifications
F; F24; F24T; F24T10/00; F24T10/20; F24T10/10; F24T10/13; F24T10/17; F28; F28F; F28F19/00; Y; Y02; Y02E; Y02E10/00; Y02E10/10; Y10; Y10S; Y10S166/00; Y10S166/902
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
198 words
A process of obtaining high temperature geothermal hot water, such as hot water at a temperature of above 300*F., as opposed to oil and like minerals, from a deep underground well without utilizing a moving mechanical or other pumping device within said well and without requiring gas-lift techniques, comprising A. positioning a well casing assembly, comprising a well casing and a conduit within said casing, in the ground to a depth sufficient to position an apertured end portion of said casing in proximity to an underground hot water supply and with an apertured end portion of said conduit adjacent said casing end portion, B. inducing flashing to steam of at least some of said hot water entering said casing end portion, C. recovering an essentially non-condensible gas, including carbon dioxide, from said flashed hot water, and D. recycling said recovered gas through said well casing assembly to bring said gas into contact with additional hot water entering said casing assembly through said apertured end portion of said casing to counteract and obviate formation of deposits which tend to clog said well casing assembly by maintaining partial pressure on the recovered carbon dioxide bearing gas under all operating conditions.
Claim 2
Dependent Claim
198 words
A process of obtaining high temperature geothermal hot water, such as hot water at a temperature of above 300*F., as opposed to oil and like minerals, from a deep underground well without utilizing a moving mechanical or other pumping device within said well and without requiring gas-lift techniques, comprising A. positioning a well casing assembly, comprising a well casing and a conduit within said casing, in the ground to a depth sufficient to position an apertured end portion of said casing in proximity to an underground hot water supply and with an apertured end portion of said conduit adjacent said casing end portion, B. inducing flashing to steam of at least some of said hot water entering said casing end portion, C. recovering an essentially non-condensible gas, including carbon dioxide, from said flashed hot water, and D. recycling said recovered gas through said well casing assembly to bring said gas into contact with additional hot water entering said casing assembly through said apertured end portion of said casing to counteract and obviate formation of deposits which tend to clog said well casing assembly by maintaining partial pressure on the recovered carbon dioxide bearing gas under all operating conditions.
Claim 3
Dependent Claim
40 words
The process of claim 1 in which said gas is recycled through said well casing assembly through said conduit so that said hot water passes into and is elevated through the space between said conduit and said surrounding well casing.
Claim 4
Dependent Claim
38 words
The process of claim 1 in which said gas is recycled through the space between said conduit and said surrounding well casing so that said hot water passes into and is elevated through said conduit within said casing.
Claim 5
Dependent Claim
146 words
The process of obtaining high temperature geothermal hot water, such as hot water at a temperature of above 300*F., as opposed to oil and like minerals, from a deep underground well without attendant precipitation of chemical compounds which would clog the well system and associated equipment and without utilizing a mechanical or other pumping device within said well and without requiring gas-lift techniques comprising A. positioning a well casing assembly, comprising a well casing and a conduit within said casing and surrounded thereby, in the ground to a depth sufficient to position an apertured end portion of said casing in proximity to an underground hot water supply and with an apertured end portion of said conduit adjacent said casing end portion, B. reducing the pressure at the well head to induce flashing to steam of at least some of said hot water entering said casing assembly,
Claim 6
Dependent Claim
146 words
The process of obtaining high temperature geothermal hot water, such as hot water at a temperature of above 300*F., as opposed to oil and like minerals, from a deep underground well without attendant precipitation of chemical compounds which would clog the well system and associated equipment and without utilizing a mechanical or other pumping device within said well and without requiring gas-lift techniques comprising A. positioning a well casing assembly, comprising a well casing and a conduit within said casing and surrounded thereby, in the ground to a depth sufficient to position an apertured end portion of said casing in proximity to an underground hot water supply and with an apertured end portion of said conduit adjacent said casing end portion, B. reducing the pressure at the well head to induce flashing to steam of at least some of said hot water entering said casing assembly,
Claim 7
Dependent Claim
99 words
The process of claim 4 which includes E. collecting and withdrawing any chemical compounds at the well head which may have formed during initial start-up of the process prior to recycling of said evolved CO2 carrying gases into said casing assembly, and F. continuing compressing and recycling said evolved gases through said casing assembly in conjunction with separation of steam and said gases from hot water elevated with said flashed steam and recycled gases to effect a substantially continuous flow of hot water from said well head without formation and build-up of said clogging chemical compounds in conjunction therewith.
Claim 8
Dependent Claim
62 words
The process of claim 4 which further includes G. heat exchanging said evolved gases and steam following separation thereof from said hot water adjacent said well head to condense said steam and to extract useful heat while cooling said gases, and H. separating said condensed steam from said cooled evolved gases prior to compressing the same for recycling through said casing assembly.
Claim 9
Dependent Claim
40 words
The process of claim 4 in which said gas is recycled through said well casing assembly through said conduit so that said hot water passes into and is elevated through the space between said conduit and said surrounding well casing.
Claim 10
Dependent Claim
38 words
The process of claim 4 in which said gas is recycled through the space between said conduit and said surrounding well casing so that said hot water passes into and is elevated through said conduit within said casing.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |