Nothing Special   »   [go: up one dir, main page]

CA1293613C - Use of zn (ii) to inhibit sulfide corrosion of cupronickel alloys - Google Patents

Use of zn (ii) to inhibit sulfide corrosion of cupronickel alloys

Info

Publication number
CA1293613C
CA1293613C CA000514658A CA514658A CA1293613C CA 1293613 C CA1293613 C CA 1293613C CA 000514658 A CA000514658 A CA 000514658A CA 514658 A CA514658 A CA 514658A CA 1293613 C CA1293613 C CA 1293613C
Authority
CA
Canada
Prior art keywords
zinc
acrylic acid
copolymers
water
corrosion
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 - Fee Related
Application number
CA000514658A
Other languages
French (fr)
Inventor
John A. Romberger
John A. Kelly
Carol B. Batton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ChampionX LLC
Original Assignee
Nalco Chemical Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nalco Chemical Co filed Critical Nalco Chemical Co
Application granted granted Critical
Publication of CA1293613C publication Critical patent/CA1293613C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Landscapes

  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Abstract

ABSTRACT
Low dosages of zinc(II) are capable of preventing the corrosion and pitting of copper and copper alloys exposed to waters containing sulfides.

Description

lZ5'3613 INTRODUCTION
Sulfides present in brackish water and seawater can cause severe corrosion and pitting of copper and its alloys.
This problem applies to such waters used industrially as coolants and for processing materials such as crude oil. There are now only two recognized treatments for this problem. The firs~ is to add tolutriazole (TT) or a similar azole to the water. Although TT protects copper alloys from most corrosion, our work shows it is not very effective against sulfide. The second method is to feed iron (II) to the water. The iron quickly oxidizes to iron (III) and precipitates sulfide in the water as iron sulfide. The disadvantage of this technique is that ferric hydroxide coats the metal surfaces and encourages under-deposit corrosion.
THE INVENTION
This invention resides in treating industrial waters containing sulfides wlth at least 0.1 ppm of zinc(II) to combat the effects of sulfide corrosion on copper and its alloys which contact these waters wherein the zinc(II) is complexed with a low molecular weight water-soluble anionic polymer. When operating at a pH below 8.0, the zinc alone will provide protection from sulfide without causing deposition and under-deposit corrosion.
The zinc(II) may be added to the sulfide containing waters at a dosage ranging between 0.1 - lOppm to reduce the sulfide corrosion of copper and copper alloys in contact with such waters. A preferred dosage is within the range of 0.5 -Sppm. These dosages are on a weight basis.
The zinc may be used in the form of any water-soluble zinc salt such as zinc chloride, zinc sulfate, zinc nitrate, zinc acetate, and the like.

~ 3~i3 Because some waters ln industrial processes are used at a pH over 8.0, it is notfeasible to add 7inc alone to the water. At pH's over 8.0, a polymer-zinc(II) complex must be used to stabilize the Zinc. Without the polymer, the zinc would precipitate as zinc hydroxide and foul the metal surfaces.Several low molecular weight anionic polymers can be used to keep zinc soluble up to pH 9Ø Such polymers are illustratively listed below:
Polymer 1. an 85/15 mole percent acrylic acid/ethyl-acrylate copolymer; Mw 3270.
Polymer 2. an 83/17 mole percent acrylic acid/methyl-acrylate copolymer; Mw 5780.
Polymer 3. a 95/5 mole percent acrylic acid/ NaAMPS
(sodium salt of 2-acrylamide-2-methylpropanesulfonic acid) copolymer; Mw 5100 and 15,300 respectively.
Polymer 4. a 90/10 mole percent acrylic acid/NaAMPS
copolymer; Mw 8280.
Polymer 5. an acrylic acid/NaAMPS copolymer.
Polymer 6. a 67/33 to 75/25 mole percent acrylic acid/hydroxypropylacrylate copolymer; Mw 735C
The use of polymers to complex zinc(IIj so that it may be used at alkaline pH's is the subject of U.S. 4,529,572.

The polymers may be selected from a broad group of acrylic acid containing copolymers with the primary limitation being that the molecular weight be within the range of 500-20,000. The preferred polymers and their use in preparing the zinc complexes are set forth in U.S. 4,529,572.

-i'~ l3 The results of Coupon tests shown below illustrate theeffect of zinc and TT. These coupon tests simulate the conditions of the water used in an industrial cooling tower, where sulfide corrosion was a problem. The addition of 3 and 7 ppm TT not only did not reduce the corrosion rate, it appears to have increased it. The addition of 1 ppm zinc(II), however, does reduce the corrosion rate significantly. The addition of 3 ppm TT and 1 ppmzinc ~II) has the same effect as the zinc alone.

3f~3 Coupon Test Results For these tests, 90/10 cupronickel coupons were placed into concentrated brackish water (1500 ppm Ca; 7000 ppm Mg; pH
8.0; conductivity 55,000 micromhos; and 0.5 ppm sulfide). The water was kept at 120 degrees F for four days. The corrosion rate was determined from the coupon weight loss after cleaning.
Treatment Corrosion Rate, mpY

None 2 5 2.4 2.3 2.6 3 ppm TT 3.5 3.5 7 ppm TT 3.0 2.9 1 ppm Zn 1.8 1.7 1 ppm Zn + 3 ppm TT 1.3 1.4

Claims (4)

1. A method for preventing the corrosion of copper and copper alloys in contact with corrosive waters containing sulfides which comprises treating such waters with at least 0.1 ppm of zinc(II), on a weight basis; wherein the zinc(II) is complexed with a low molecular weight water-soluble anionic polymer.
2. The method of Claim 1 wherein the said corrosive waters are at a pH of 8 or higher.
3. The method of Claim 1 wherein the amount of zinc(II) is in the range from 0.1 to 10ppm, on a weight basis.
4. The method of Claim 2 or 3 wherein the low molecular weight water-soluble anionic polymer is selected from the group consisting of acrylic acid/ethyl acrylate copolymers, acrylic acid/methyacrylate copolymers, acrylic acid/2-acrylamido-2-methylpropane sulfonic acid copolymers, or acrylic acid/hydroxypropyl acrylate copolymers, said copolymers having a molecular weight within the range of 500 to 20,000 being utilized to confer water-solubility of the zinc(II) up to a pH
of 9Ø
CA000514658A 1985-08-05 1986-07-25 Use of zn (ii) to inhibit sulfide corrosion of cupronickel alloys Expired - Fee Related CA1293613C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US76222385A 1985-08-05 1985-08-05
US762,223 1985-08-05

Publications (1)

Publication Number Publication Date
CA1293613C true CA1293613C (en) 1991-12-31

Family

ID=25064442

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000514658A Expired - Fee Related CA1293613C (en) 1985-08-05 1986-07-25 Use of zn (ii) to inhibit sulfide corrosion of cupronickel alloys

Country Status (1)

Country Link
CA (1) CA1293613C (en)

Similar Documents

Publication Publication Date Title
US4443340A (en) Control of iron induced fouling in water systems
US5130052A (en) Corrosion inhibition with water-soluble rare earth chelates
US5342540A (en) Compositions for controlling scale formation in aqueous system
US3885914A (en) Polymer-zinc corrosion inhibiting method
EP0188884A1 (en) Method of controlling iron induced fouling in water systems
CA1291635C (en) Composition of corrosion inhibitors for cooling water systems using chemically modified acrylamide or methacrylamide polymers
NL8002394A (en) CORROSION-BRAKING AGENT.
US5320779A (en) Use of molybdate as corrosion inhibitor in a zinc/phosphonate cooling water treatment
US2793932A (en) Corrosion inhibiting
US4502978A (en) Method of improving inhibitor efficiency in hard waters
CA1309854C (en) Inhibiting corrosion of iron base metals
US5192447A (en) Use of molybdate as a cooling water corrosion inhibitor at higher temperatures
CA1074552A (en) Pyrophosphate-zinc corrosion
KR890002246B1 (en) Water treatment agent
US4529572A (en) Polymer-zinc corrosion inhibitor
CA1293613C (en) Use of zn (ii) to inhibit sulfide corrosion of cupronickel alloys
EP0311192B1 (en) Method of controlling corrosion at high ph
Rajendran et al. Synergistic effect of Zn exp 2+ and phenyl phosphonic acid in corrosion inhibition of mild steel in neutral environment
KR900003981B1 (en) Method for corrosion inhibition of metals
CA2112642A1 (en) Method for inhibiting corrosion of metals using polytartaric acids
US4105406A (en) Method of inhibiting corrosion using a hexametaphosphate and a phosphate buffer
US4434059A (en) Polymers for prevention of fouling by iron oxides in cooling systems
CA2061249C (en) Use of cationic alkyl-phosphonium salts as corrosion inhibitors in open recirculating systems
EP0339716B1 (en) Method and compositions for controlling corrosion in low and high hardness water
CA1340659C (en) Anti-scale and corrosion inhibitor

Legal Events

Date Code Title Description
MKLA Lapsed