US4749550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of inhibiting corrosion in aqueous systems
Assignee: BP PLC
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Filing: 1986-12-23
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Granted: 1988-06-07
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Expires: 2006-12-23
Abstract
Abstract A method of inhibiting corrosion of a metal surface in an aqueous system comprising introducing corrosion inhibiting cations into the aqueous system. The corrosion inhibiting cations are selected from the group comprising cations of yttrium and cations of the metals of the lanthanum series which metals have atomic numbers from 57 to 71 inclusive. The cations may be introduced in the form of water soluble salts. Alternatively the cations may be releasably bound by ion exchange to a substrate and the ion-exchanged substrate introduced into the aqueous system.
Inventors
- 👤 Brian P. F. Goldie
- 👤 John J. McCarroll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:48
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/18
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
110 words
A method of inhibiting corrosion of a metal surface in contact with an aqueous system comprising introducing into the aqueous system, cations selected from the group consisting of cations of yttrium and cations of the metals of the lanthanide series, said cations being introduced in the form of material capable of releasing said cations into the aqueous system to produce a solution of said cations wherein the material is selected from the group consisting of nitrate, chloride, bromide, iodide, acetate and sulphate salts of said cations and cation-exchanged substrates including said cations and said metal surface being in contact with said solution for a period of at least 7 days.
Claim 2
Independent Claim
110 words
A method of inhibiting corrosion of a metal surface in contact with an aqueous system comprising introducing into the aqueous system, cations selected from the group consisting of cations of yttrium and cations of the metals of the lanthanide series, said cations being introduced in the form of material capable of releasing said cations into the aqueous system to produce a solution of said cations wherein the material is selected from the group consisting of nitrate, chloride, bromide, iodide, acetate and sulphate salts of said cations and cation-exchanged substrates including said cations and said metal surface being in contact with said solution for a period of at least 7 days.
Claim 3
Dependent Claim
16 words
A method as claimed in claim 1 in which the aqueous system is an aerobic system.
Claim 4
Dependent Claim
35 words
A method as claimed in claim 1 in which the metal surface is a member of the group consisting of ferrous metal, copper and aluminium which is intermittently or continuously in contact with said solution.
Claim 5
Dependent Claim
25 words
A method as claimed in claim 1 in which the concentration in solution of the corrosion inhibiting cations is at least 0.4 millimoles per liter.
Claim 6
Dependent Claim
25 words
A method as claimed in claim 1 in which the concentration in solution of the corrosion inhibiting cations is at least 0.1 millimoles per liter.
Claim 7
Dependent Claim
31 words
A method as claimed in claim 1 in which the corrosion inhibiting cations are releasably bound by ion-exchange to a substrate and the cation-exchanged substrate is contacted with the aqueous system.
Claim 8
Dependent Claim
34 words
A method as claimed in claim 6 in which the cation-exchanged substrate is contacted with a portion of the aqueous system which is passed through a fixed or fluidized bed comprising the ion-exchanged substrate.
Claim 9
Dependent Claim
15 words
A method as claimed in claim 6 in which the cation-exchanged substrate is a zeolite.
Claim 10
Dependent Claim
17 words
A method as claimed in claim 6 in which the cation-exchanged substrate is an organic cation-exchange resin.
Claim 11
Dependent Claim
19 words
A method as claimed in claim 6 in which the substrate is formed of particles of an inorganic oxide.
Claim 12
Dependent Claim
30 words
A method as claimed in claim 10 in which the inorganic oxide is selected from the group comprising silica, alumina, zirconia, iron oxide, tin oxide mixed metal oxides and kaolinite.
Claim 13
Dependent Claim
15 words
A method as claimed in claim 10 in which the inorganic oxide is activated silica.
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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) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |