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Patent US4500434A successfully refreshed from Google Patents.
US4500434A
Expired / Lapsed
US
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Inhibiting scale precipitation from high temperature brine
Assignee: Union Oil Company of California
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Filing: 1982-12-02
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Granted: 1985-02-19
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Expires: 2002-12-02
Abstract
Abstract A method for inhibiting the precipitation of a scale, such as an iron silicate scale, from a hot aqueous brine solution, such as a geothermal brine, during production and handling of the brine wherein there is injected into the brine a brine-soluble acid in an amount sufficient to lower the pH of the brine from 0.1 to 0.3 pH units.
Inventors
- 👤 John W. Jost
- 👤 Darrell L. Gallup
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:46
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; Y; Y10; Y10S; Y10S423/00; Y10S423/19
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
90 words
A method for inhibiting the precipitation of iron silicate scale from a pressurized aqueous brine solution having a pH of about 5 to about 6, which solution contains dissolved scale-forming salts, during passage of the said fluid stream through industrial equipment wherein the pressure is reduced so that at least a portion of the solution flashes to steam and dissolving such scale previously formed comprising adding to the solution an amount of water-soluble acid sufficient to lower the pH of the solution by between about 0.1 and 0.3 pH unit.
Claim 2
Independent Claim
90 words
A method for inhibiting the precipitation of iron silicate scale from a pressurized aqueous brine solution having a pH of about 5 to about 6, which solution contains dissolved scale-forming salts, during passage of the said fluid stream through industrial equipment wherein the pressure is reduced so that at least a portion of the solution flashes to steam and dissolving such scale previously formed comprising adding to the solution an amount of water-soluble acid sufficient to lower the pH of the solution by between about 0.1 and 0.3 pH unit.
Claim 3
Dependent Claim
15 words
The method defined in claim 1 wherein the aqueous brine solution is a geothermal brine.
Claim 4
Dependent Claim
22 words
The method defined in claim 1 wherein the aqueous brine solution is a geothermal fluid comprising a mixture of brine and steam.
Claim 5
Dependent Claim
28 words
The method defined in claim 1 wherein the water-soluble acid is added to the aqueous brine solution before the pressure of the aqueous brine solution is substantially reduced.
Claim 6
Dependent Claim
26 words
The method defined in claim 1 wherein the water-soluble acid is selected from the group consisting of inorganic material acids, organic carboxylic acids, and mixtures thereof.
Claim 7
Dependent Claim
14 words
The method defined in claim 5 wherein the water soluble acid is hydrochloric acid.
Claim 8
Dependent Claim
19 words
The method defined in claim 1 wherein about 50 to 180 weight parts per million water-soluble acid is employed.
Claim 9
Independent Claim
96 words
A method for inhibiting the precipitation of iron silicate scale from a hot pressurized geothermal fluid, having a pH about 5 to about 6 and containing dissolved salts including iron ions and silica species, during passage of the geothermal fluid through industrial equipment wherein the pressure is reduced so that at least a portion of the geothermal fluid flashes to steam and dissolving such scale previously formed, comprising adding to the geothermal fluid an amount of a water-soluble acid sufficient to lower the pH of the geothermal fluid by between about 0.1 to 0.3 pH unit.
Claim 10
Independent Claim
96 words
A method for inhibiting the precipitation of iron silicate scale from a hot pressurized geothermal fluid, having a pH about 5 to about 6 and containing dissolved salts including iron ions and silica species, during passage of the geothermal fluid through industrial equipment wherein the pressure is reduced so that at least a portion of the geothermal fluid flashes to steam and dissolving such scale previously formed, comprising adding to the geothermal fluid an amount of a water-soluble acid sufficient to lower the pH of the geothermal fluid by between about 0.1 to 0.3 pH unit.
Claim 11
Dependent Claim
17 words
The method defined in claim 8 wherein the geothermal fluid comprises a mixture of brine and steam.
Claim 12
Dependent Claim
26 words
The method defined in claim 8 wherein the water-soluble acid is added to the geothermal fluid before the pressure of the geothermal fluid is substantially reduced.
Claim 13
Dependent Claim
26 words
The method defined in claim 8 wherein the water-soluble acid is selected from the group consisting of inorganic mineral acids, organic carboxylic acids, and mixtures thereof.
Claim 14
Dependent Claim
13 words
The method defined in claim 11 wherein the water-soluble acid is hydrochloric acid.
Claim 15
Dependent Claim
19 words
The method defined in claim 8 wherein about 50 to 180 weight parts per million water-soluble acid is employed.
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) | 1988-02-19 | 1988-08-20 | 1989-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-19 | 1992-08-20 | 1993-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-19 | 1996-08-20 | 1997-02-19 | $7700.00 | Window Closed / Lapsed |