US2797199A - Corrosion inhibitor - Google Patents
Corrosion inhibitor Download PDFInfo
- Publication number
- US2797199A US2797199A US379718A US37971853A US2797199A US 2797199 A US2797199 A US 2797199A US 379718 A US379718 A US 379718A US 37971853 A US37971853 A US 37971853A US 2797199 A US2797199 A US 2797199A
- Authority
- US
- United States
- Prior art keywords
- sulfite
- thiourea
- inhibitor
- corrosion
- steam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
Definitions
- This invention relates to a corrosion inhibiting com- Parallel compositions in which potassium sulfite, calcium sulfite and magnesium sulfite are substituted for the sodium sulfite are approximately equally effective.
- the alkali metal sulfites are preferred over the alkaline earth metal sulfites, especially if the water charged to the boiler has an appreciable carbonate or sulfate content.
- the usual steam generating systems comprise a boiler in which water is heated to temperatures ordinarily in the range from 250 F. to 500 F. to generate steam, a steam line to carry the steam from the boiler to the point of use, the heat exchangers, turbines etc. where the steam is condensed, and a condensate line to return condensed spent steam to the boiler drum.
- Steam generating systems are ordinarily constructed of iron or steel which corrodes in normal usage with the result that maintenance costs are increased and equipment life is shortened.
- a corrosion inhibitor consisting essentially of thiourea, diphenylthiourea and an alkali metal sulfite or an alkaline earth metal sulfite effectively inhibits the corrosion of the boiler, steam lines and condensate lines of steam generation systems when introduced into the boiler water in small amounts, usually in the range from 0.001 to 0.2% by weight of the total water (liquid and vapor) in the steam generation system.
- the three components of the corrosion inhibiting comp osition may be present in varying proportions such that the percent of each component in the total corrosion inhibitor composition lies in the range from 10 to 45% by weight. It is preferred to employ approximately equal weights of the three components in compounding the inhibitor compositions.
- Representative eltective compositions are listed in the following Table I:
- the inhibitors of the invention are prepared by melting the thioruea and diphenylthiourea and stirring the sulfite into the molten mixture.
- the mixing is ordinarily carried out at temperatures in the range from to 200 C.
- the mixture is allowed to cool and the product is a solid having a softening point at about 150 C. and a yellowish color ranging from brownish yellow to light yellow, depending upon the proportions of the components employed.
- the manner in which the three components interact during the produc tion of the solid inhibitor and under the conditions of use is not clear. It is observed, however, that under condi tions of use a strong garlic-like odor is developed in the vapor phase in the boiler drum which cannot be attributable to any individual component.
- the solid inhibitor can be cast into sticks or pellets which are introduced as such into the boiler drum of the steam generation system. If desired, the inhibitor may be dispersed in makeup water charged to the system and added as a concentrated dispersion.
- a cohesive solid corrosion inhibitor adapted to inhibit corrosion of ferrous metals in steam generating systems when employed in concentrations in the range about 0.001 to about 0.2% by weight consisting essentially of an intimate mixture of approximately equal parts by weight of thiourea, diphenylthiourea and an alkali metal sulfite, said inhibitor being prepared by dispersing the sulfite in a molten mixture of thiourea and diphenyl thiourea.
- composition as defined in claim 1, wherein the sulfite is sodium sulfite.
Description
United States Patent No Drawing. Application September 11, 1953, Serial No. 379,718
2 Claims. (Cl. 252-=-391) This invention relates to a corrosion inhibiting com- Parallel compositions in which potassium sulfite, calcium sulfite and magnesium sulfite are substituted for the sodium sulfite are approximately equally effective. The alkali metal sulfites are preferred over the alkaline earth metal sulfites, especially if the water charged to the boiler has an appreciable carbonate or sulfate content.
Data indicating the unusual effectiveness of the inhibitors of the invention are summarized in the following Table II. The inhibitors were introduced into the boiler water in amounts sulficient to give the boiler water an inhibitor content of 2000 parts per mill-ion. Iron coupons were suspended in the liquid phase in the boiler drum, in the steam line and in the condensate line. Corrosion rates are expressed in mils per year and were calculated from the weight loss of the coupons during the tests.
TABLE II Corrosion rates mils/year inhibitors added to water in boiler drum at 2000 parts per million Equal Equal Equal Equal Parts Parts Parts Parts Thiourea Diphenyl Diphenyl 'lhlourea No In- Thiourea Diphenyl Sodium and hiourea Thlourea Dlphenyl hibitor hiourea Sulfite Sodium and and 'Ihlourea Sulfite Sodium Thiourea andSodiurn Condensate line and heat exchanger 11 4 3 6 2.5 8 2 0.5
position which is highly effective in inhibiting corrosion of ferrous metals in steam generation systems. I
The usual steam generating systems comprise a boiler in which water is heated to temperatures ordinarily in the range from 250 F. to 500 F. to generate steam, a steam line to carry the steam from the boiler to the point of use, the heat exchangers, turbines etc. where the steam is condensed, and a condensate line to return condensed spent steam to the boiler drum. Steam generating systems are ordinarily constructed of iron or steel which corrodes in normal usage with the result that maintenance costs are increased and equipment life is shortened.
It has now been found that a corrosion inhibitor consisting essentially of thiourea, diphenylthiourea and an alkali metal sulfite or an alkaline earth metal sulfite effectively inhibits the corrosion of the boiler, steam lines and condensate lines of steam generation systems when introduced into the boiler water in small amounts, usually in the range from 0.001 to 0.2% by weight of the total water (liquid and vapor) in the steam generation system.
The three components of the corrosion inhibiting comp osition may be present in varying proportions such that the percent of each component in the total corrosion inhibitor composition lies in the range from 10 to 45% by weight. It is preferred to employ approximately equal weights of the three components in compounding the inhibitor compositions. Representative eltective compositions are listed in the following Table I:
TABLE I Composition No.
Thiourea "percent" 10 45 37. 5 33 Diphenylthiourea .do 45 10 37. 5 i 33 Sodium sulfite do 46 35 25 33 From the foregoing data it is evident that the threecomponent inhibitor of the invention is markedly more effective than any of the individual components or any pair of individual components.
The inhibitors of the invention are prepared by melting the thioruea and diphenylthiourea and stirring the sulfite into the molten mixture. The mixing is ordinarily carried out at temperatures in the range from to 200 C. After mixing is complete, the mixture is allowed to cool and the product is a solid having a softening point at about 150 C. and a yellowish color ranging from brownish yellow to light yellow, depending upon the proportions of the components employed. The manner in which the three components interact during the produc tion of the solid inhibitor and under the conditions of use is not clear. It is observed, however, that under condi tions of use a strong garlic-like odor is developed in the vapor phase in the boiler drum which cannot be attributable to any individual component.
The solid inhibitor can be cast into sticks or pellets which are introduced as such into the boiler drum of the steam generation system. If desired, the inhibitor may be dispersed in makeup water charged to the system and added as a concentrated dispersion.
I claim:
1. A cohesive solid corrosion inhibitor adapted to inhibit corrosion of ferrous metals in steam generating systems when employed in concentrations in the range about 0.001 to about 0.2% by weight consisting essentially of an intimate mixture of approximately equal parts by weight of thiourea, diphenylthiourea and an alkali metal sulfite, said inhibitor being prepared by dispersing the sulfite in a molten mixture of thiourea and diphenyl thiourea.
2. The composition as defined in claim 1, wherein the sulfite is sodium sulfite.
References Cited in the file of this patent UNITED STATES PATENTS
Claims (1)
1. A COHESIVE SOLID CORROSION INHIBITOR ADAPTED TO INHIBIT CORROSION OF FERROUS METALS IN STEAM GENERATING SYSTEMS WHEN EMPLOYED IN CONCENTRATIONS IN THE RANGE ABOUT 0.001 TO ABOUT 0.2% BY WEIGHT CONSISTING ESSENTIALLY OF AN INTIMATE MIXTURE OF APPROXIMATELY EQUAL PARTS BY WEIGHT OF THIOUREA,DIPHENYLTHIOUREA AND AN ALKALI METAL SULFITE, SAID INHIBITOR BEING PREPARED BY DISPERSING THE SULFITE IN A MOLTEN MIXTURE OF THIOUREA AND DIPHENYL THIOUREA.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US379718A US2797199A (en) | 1953-09-11 | 1953-09-11 | Corrosion inhibitor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US379718A US2797199A (en) | 1953-09-11 | 1953-09-11 | Corrosion inhibitor |
Publications (1)
Publication Number | Publication Date |
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US2797199A true US2797199A (en) | 1957-06-25 |
Family
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Application Number | Title | Priority Date | Filing Date |
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US379718A Expired - Lifetime US2797199A (en) | 1953-09-11 | 1953-09-11 | Corrosion inhibitor |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3133028A (en) * | 1960-02-18 | 1964-05-12 | Wright Chem Corp | Corrosion inhibition |
US3422022A (en) * | 1966-10-27 | 1969-01-14 | Betz Laboratories | Reduced fouling of steam turbines by treatment with sulfur containing compounds |
US3447974A (en) * | 1966-03-14 | 1969-06-03 | Enthone | Composition and method for blackening metal article surfaces |
FR2385812A1 (en) * | 1977-03-28 | 1978-10-27 | Dow Chemical Co | QUATERNARY PYRIDINIUM SALT INHIBITOR SYSTEM FOR GAS CONDITIONING SOLUTIONS |
FR2385813A1 (en) * | 1977-03-28 | 1978-10-27 | Dow Chemical Co | COBALT SALTS INHIBITOR SYSTEM FOR GAS PACKAGING SOLUTIONS |
US5368774A (en) * | 1992-07-30 | 1994-11-29 | Baker Hughes Incorporated | Water soluble corrosion inhibitor effective against corrosion by carbon dioxide |
WO2019246503A1 (en) * | 2018-06-22 | 2019-12-26 | Ideaz, Llc | Diphenyl tablets and methods of preparing the same |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2238651A (en) * | 1937-05-21 | 1941-04-15 | Du Pont | Inhibition of corrosion |
US2562549A (en) * | 1945-10-17 | 1951-07-31 | Hall Lab Inc | Treatment of steam systems |
-
1953
- 1953-09-11 US US379718A patent/US2797199A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2238651A (en) * | 1937-05-21 | 1941-04-15 | Du Pont | Inhibition of corrosion |
US2562549A (en) * | 1945-10-17 | 1951-07-31 | Hall Lab Inc | Treatment of steam systems |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3133028A (en) * | 1960-02-18 | 1964-05-12 | Wright Chem Corp | Corrosion inhibition |
US3447974A (en) * | 1966-03-14 | 1969-06-03 | Enthone | Composition and method for blackening metal article surfaces |
US3422022A (en) * | 1966-10-27 | 1969-01-14 | Betz Laboratories | Reduced fouling of steam turbines by treatment with sulfur containing compounds |
FR2385812A1 (en) * | 1977-03-28 | 1978-10-27 | Dow Chemical Co | QUATERNARY PYRIDINIUM SALT INHIBITOR SYSTEM FOR GAS CONDITIONING SOLUTIONS |
FR2385813A1 (en) * | 1977-03-28 | 1978-10-27 | Dow Chemical Co | COBALT SALTS INHIBITOR SYSTEM FOR GAS PACKAGING SOLUTIONS |
US5368774A (en) * | 1992-07-30 | 1994-11-29 | Baker Hughes Incorporated | Water soluble corrosion inhibitor effective against corrosion by carbon dioxide |
WO2019246503A1 (en) * | 2018-06-22 | 2019-12-26 | Ideaz, Llc | Diphenyl tablets and methods of preparing the same |
US11877576B2 (en) | 2018-06-22 | 2024-01-23 | Ideaz, Llc | Diphenyl tablets and methods of preparing the same |
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