US4388194A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrogen sulfide abatement in geothermal steam systems
Assignee: FMC Corp
•
Filing: 1981-09-04
•
Granted: 1983-06-14
•
Expires: 2001-09-04
Abstract
Abstract A method of preventing sludge deposition in the treatment of geothermal steam condensate with iron catalyzed/hydrogen peroxide by carrying out the treatment in the presence of an inorganic polyphosphate.
Inventors
- 👤 William A. Hills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:58
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/72; C02F1/722; C02F5/00; C02F5/08; C02F5/086
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
93 words
In the process of removing hydrogen sulfide from an aqueous waste stream including steam condensate from a geothermal power plant by treating the stream with an iron catalyst/hydrogen peroxide oxidant system, the improvement of preventing deposition of sludge comprising carrying out the treatment in the presence of an effective amount of a soluble polyphosphate selected from the class consisting of: ______________________________________
M.sub.4 P.sub.2 O.sub.7
M.sub.3 P.sub.3 O.sub.10
(MPO.sub.3).sub.n
I II III
Pyrophosphate
Tripolyphosphate
Higher Polyphosphate
______________________________________ wherein M represents an alkali metal and n is an integer of from about 6 to 21.
Claim 2
Dependent Claim
93 words
In the process of removing hydrogen sulfide from an aqueous waste stream including steam condensate from a geothermal power plant by treating the stream with an iron catalyst/hydrogen peroxide oxidant system, the improvement of preventing deposition of sludge comprising carrying out the treatment in the presence of an effective amount of a soluble polyphosphate selected from the class consisting of: ______________________________________
M.sub.4 P.sub.2 O.sub.7
M.sub.3 P.sub.3 O.sub.10
(MPO.sub.3).sub.n
I II III
Pyrophosphate
Tripolyphosphate
Higher Polyphosphate
______________________________________ wherein M represents an alkali metal and n is an integer of from about 6 to 21.
Claim 3
Dependent Claim
21 words
The process according to claim 1 wherein the treatment is carried out in a pH range of about 7.5 to 9.
Claim 4
Dependent Claim
18 words
The process according to claim 2 wherein the polyphosphate is tetrasodium pyrophosphate of the formula: Na.sub.4 P.sub.2 O.sub.7.
Claim 5
Dependent Claim
20 words
The process according to claim 2 wherein the polyphosphate is tetrasodium pyrophosphate decahydrate of the formula: Na.sub.4 P.sub.2 O.sub.7.10H.sub.2 O.
Claim 6
Dependent Claim
18 words
The process according to claim 2 wherein the polyphosphate is sodium tripolyphosphate of the formula: Na.sub.3 P.sub.3 O.sub.10.
Claim 7
Dependent Claim
16 words
The process according to claim 2 wherein the polyphosphate is a polyphosphate of the formula: (NaPO.sub.3).sub.6.
Claim 8
Dependent Claim
16 words
The process according to claim 2 wherein the polyphosphate is a polyphosphate of the formula: (NaPO.sub.3).
Claim 9
Dependent Claim
16 words
The process according to claim 2 wherein the polyphosphate is a polyphosphate of the formula: (NaPO.sub.3).sub.21.
References Cited (Backward Citations)
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US3622273A
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US3705098A
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US4189462A
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US4076621A
Cited
US4151260A
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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) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |