WO1988001656A2

WO1988001656A2 - Polyethylene glycol-containing corrosion inhibitors

Info

Publication number: WO1988001656A2
Application number: PCT/US1987/002154
Authority: WO
Inventors: Philip R. Engelhardt; Barry A. Metz
Original assignee: Wright Chemical Corporation
Priority date: 1986-08-28
Filing date: 1987-08-26
Publication date: 1988-03-10
Also published as: ES2004992A6; AU8031787A; ZA876391B; WO1988001656A3

Abstract

A corrosion-inhibiting formulation for use in water cooling towers, comprising approximately 65-70 % water, 8-12 % polyethylene glycol having a molecular weight of between 200 and 20,000, and either a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid, or a combination of hydroxy ethylidene diphosphonic acid, phosphinocarboxylic acid, and tolyltriazole.

Description

POLYETHYLENE GLYCOL-CONTAINING CORROSION INHIBITORS

DESCRIPTION

Field of the Invention

The invention pertains to cooling water corrosion formulations which effectively control corrosion and have a less deleterious effect on the environment than prior art formulations. Particularly, the invention pertains to cooling water corrosion inhibitors including water, polyethylene glycol, and either a copolymer of acrylamidomethyl propane sulfonic acid or a combiantion of hydroxy ethylidene diphosphonic acid, phosphinocarboxylic acid, and tolyltriazole. Background of the Invention

Prior to about 1982, cooling water corrosion inhibition had been primarily effected through compositions containing the hexavalent chromate ion, either alone or in combination with phosphates and cathodic inhibitors such as zinc salts. When used alone, the chromates were required in concentrations above 200 mg per liter and were usually in the form of a salt such as Na₂CrO₄. In combination with 5-10 mg per liter zinc ions, the required level of chromate fell to about 20 mg per liter. Mild steel corrosion rates of 0.2 to 1.0 mils per year (mpy) were typical of chromate-based treatments.

Due to increasing demands by federal, state, and local agencies over the amounts of industrial effluents discharged into streams and sewage treatment systems, the demand for non-chromate-containing cooling water corrosion inhibitors increased steadily.

Recirculating cooling water systems are still being converted from chromate-based treatments to non-chromate based treatments, such as phosphate-, zinc-, molybdate-, silicate-, and totally organic-based systems. However, such treatments are not as cost-effective as chromate-based treatments. For example, totally organic treatments at levels of 100 mg per liter resulted in mild steel corrosion rates in excess of those using lesser amounts of zinc ion and chromate-based treatments. About the best possible mild steel corrosion rates with such totally organic treatments was about 5 mpy.

Beginning in 1982, Wright Chemical Corporation of Schiller Park, Illinois, the Assignee of the present invention, discovered that blends of various organics, molybdate-organics, and stabilized phosphates in combination with a low molecular weight polymeric diol resulted in a composition which functioned as a metal surface cleaner and general dispersant. Through a process of "chemisorption", that is the process of adsorption on the surface by means of a heterogenous reaction through which molecules of the surrounding medium react with molecules or atoms of the solid phase, a new substance in the form of an independent phase is formed on the metal. Through chemisorption, the surface deposition was removed, thereby eliminating potential areas of localized attack. In this manner, the polymeric diol promoted an even, tenacious film across the entire metal surface.

Personnel at Wright Chemical performed tests upon many different combinations of polymeric diols with phosphonate and triazole to screen for corrosion-inhibition potential. Of the polymeric diol combinations tested, only one formulation showed promise at a level of 100 mg per liter or less. This successful inhibitor was marketed under the trade name "Wrico J-4764", and was described in a publication entitled "Application of a New Environmentally Acceptable Cooling Water Treatment," presented at the 44th Annual Meetings International Water Conference, Pittsburgh, Pennsylvania, between October 24 and October 26,

1983. This formulation was also known as Inhibitor J and comprised 75.4% water, 10.0% polyethylene glycol having a molecular weight of 20,000, 4.6% tolyltriazole, and 10.0% hydroxy ethylidene diphosphonic acid (HEDP). At 100 mg per liter. Inhibitor J limited corrosion rates to 2.0 mpy on steel laboratory towers and 0.1 mpy on brass laboratory towers. Inhibitor J was also discussed in a paper presented at the 45th Annual Meeting of the International Water Conference in Pittsburgh, Pennsylvania, from October 22 through October 24,

1984, entitled "Operational Experience with a New Environmentally Acceptable Cooling Water Treatment."

Wright Chemical has manufactured formulations of water and polymeric diols with various other compounds which have proven effective as inhibitors. These formulations have included compounds such as ethylene diamine tetra acetate, benzotriazole, caustic soda, sodium molybdate dihydrate, sodium nitrate, sodium silicate, tolyltriazole, hydroxy ethylidene diphosphonic acid, carboxymethyl cellulose, sodium polyacrylate, silicone and non-silicone anti-foam agents, and polymaleic acid.

Summary of the Invention

The present invention is a corrosion-inhibiting formulation for use in water cooling towers, comprising 65-70% water, 8-12% polyethylene glycol having a molecular weight of between 200 and 20,000, and either (1) a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid, or (2) hydroxy ethylene diphosphonic acid, phosphinocarboxylic acid, and tolyltriazole. These formulations have been found to give excellent results in tests determining mils per year of corrosion.

Description of the Preferred Embodiment

Typical formulations in accordance with the invention are Wrico DT-111, Wrico DT-112, Wrico DT-114, and Wrico DT-414. "Wrico" is a trademark of Wright Chemical Corporation, Schiller Park, Illinois, for compositions useful in water treatment. All concentrations given herein are weight percent. Each of the four formulations set forth in Examples 1-4 may be made by simply blending the listed ingredients in the amounts specified.

Example 1

Wrico DT-111 is comprised of water; polyethylene glycol; and a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid:

Water 65.4%

Carbowax 200 10.0%

Belclene 283 5.0%

Belcor 575 10.0%

Dequest 2010 5.0%

Cobratec

TT-50S 4.6%

Total 100.0%

Carbowax 200 is a Union Carbide Co. trademark for polyethylene glycol having a molecular weight of 200; Belclene 283 is a Ciba-Geigy Corp. trademark for a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid; Belcor 575 is a Ciba-Geigy Corp. trademark for hydroxyphosphocarboxylic acid; Dequest 2010 is a Monsanto Corp. trademark for hydroxy ethylidene diphosphonic acid (HEDP); and Cobratec TT-50S is a Sherwin-Williams Corp. trademark for tolyltriazole. Example 2

Wrico DT-112 is comprised of water; polyethylene glycol; and a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid:

Water 65.4%

Polyethylene glycol

(molecular weight 200) 10.0%

Belclene 283 5.0%

Belcor 575 5.0%

Dequest 2010 10.0%

Cobratec

TT-50S 4.6%

Total 100.0%

Example 3

Wrico DT-114 is a corrosion-inhibiting formulation comprised of water; polyethylene glycol; hydroxy ethylidene diphosphonic acid; phosphinocarboxylic acid; and tolyltriazole:

Water 67.7%

Polyethylene glycol

(molecular weight 200) 10.0%

Dequest 2010 10.0%

Belsperse 161 10.0%

Cobratec

TT-50S 2.3%

Total 100.0%

Belsperse 161 is a Ciba-Geigy Corp. trademark for a brand of phosphinocarboxylic acid.

Example 4

Wrico DT-414 is a corrosion-inhibiting formulation comprised of water; polyethylene glycol; and a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid:

Water 70.0%

Polyethylene glycol

(molecular weight 20,000) 10.0%

Belclene 283 10.0%

Belclene 400 10.0%

Total 100.0%

Belclene 400 is a Ciba-Geigy Corp. trademark for its brand of a copolymer of acrylamidomethyl propane sulfonic acid and acrylic acid.

Two comparison tests were made. In the first comparison test, corrosion rates in a 1018 mild steel condenser and an admiralty brass condenser tube were determined. A two-component treatment regimen of Wright Chemical Corporation's DT-212 at 100 parts per million and DT-414 at 50 parts per million was used. For comparison purposes, DT-212 at 100 parts per million and DT-414, but without polyethylene glycol, at 50 parts per million was used. The comparison was made in a bench-scale laboratory cooling tower which consisted of a basin, a feed tube water tank, a centrifigal pump, glass jackets, a plexiglass tower, and mild steel and admiralty brass heat exchangers. Chemical treatment and make-up water was fed continuously from chemical and feed water tanks. The bulk water was circulated at a velocity of approximately one foot per second, and the temperature of the recirculated water was 110° F. 4° F. The desired system concentration was obtained by adjusting the blowdown valve.

The corrosion test specimens were 1018 mild steel coupons, three inches in length and 3/8 inch in diameter. These coupons were preweighed prior to exposure. The loss in weight was determined subsequent to exposure over a given length of time, and this loss was then extrapolated to give a corrosion rate in mils per year (mpy). A 1018 mild steel condensor and an admiralty brass condensor tube, having a ½-inch O.D., were used as heat exchangers. Deposits on these tubes were removed and analyzed. The results of the laboratory tower test using DT-212 and DT-414 with or without polyethylene glycol was as follows:

@

A similar comparison was made between Wrico Formulation J-4764 and Wrico Formulation No. DT-112, the latter being a formulation within the scope of the present invention. Treatment J-4764 and DT-112 are identical, except that in DT-112 10.0% of the water is replaced with 5.0% of a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid; and 5.0% of hydroxyphosphocarboxylic acid. The results of the test are as follows:

@

Table I indicates that the addition of polyethylene glycol to corrosion-inhibiting formulations decreases the corrosion rate in steel and brass condensor tubes. Table II indicates that the addition of (1) a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid and (2) hydroxyphosphocarboxylic acid results in decreased corrosion rates on steel and admiralty brass condensor tubes. The above Tables also indicate that corrosion-inhibiting formulation levels as low as 100 ppm give acceptable results in cooling tower corrosion inhibition. Particularly, treatments in accordance with the present invention result in corrosion rates well below 5.0 mpy.

PCT WORLD INTELLECTUAL PROPER OR ANIZATION International Bureau

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(51) International Patent Classification 4 (11) International Publication Number : WO 88/ 01 C23F 11/173, 11/10 A3

(43) International Publication Date: 10 March 1988 (10.0

(21) International Application Number : PCT/US87/02154 (81) Designated States: AT (European patent), AU, BE ropean patent), CH (European patent), DE, DE

(22) International Filing Date: 26 August 1987 (26.08.87) ropean patent), DK, FR (European patent), GB, (European patent), IT (European patent), LU (E pean patent), MW, NL, NL (European patent),

(31) Priority Application Number: 901,715 SE (European patent).

(32) Priority Date: 28 August 1986 (28.08.86)

Published

(33) Priority Country: US With international search report.

Before the expiration of the time limit for amending claims and to be republished in the event of the recei

(71) Applicant: WRIGHT CHEMICAL CORPORATION amendments.

[US/US]; 4328 North United Parkway, Schiller Park, IL 60176 (US). (88) Date of publication of the international search report:

(72) Inventors: ENGELHARDT, Philip, R. ; 200 South Burr 19 May 1988 (19.05.

Oak Drive, Lake Zurich, IL 60047 (US). METZ, Barry, A. ; 3442 Wilmette Avenue, Wilmette, IL 60091 (US).

(74) Agents: RATH, Ralph, R. et al.; Wallenstein Wagner Hattis Strampel & Aubel, 100 South Wacker Drive, Suite 2100, Chicago, IL 60606 (US).

(54) Title: POLYETHYLENE GLYCOL-CONTAINING CORROSION INHIBITORS

(57) Abstract

A corrosion-inhibiting formulation for use in water cooling towers, comprising approximately 65-70 % water, 8-1 polyethylene glycol having a molecular weight of between 200 and 20,000, and either a copolymer of acrylamidomet propane sulfonic acid and polymaleic acid, or a combination of hydroxy ethylidene diphosphonic acid, phosphinocarb ylic acid, and tolyltriazole.

FOR HIE PURPOSES OF INFORMATION ONLY

Codes used to identify States party to the PCT on the frontpages of pamphlets publishing international applications under the PCT.

AT Austria FR France ML Mali

AU Australia GA Gabon MR Mauritania

BB Barbados GB United Kingdom MW Malawi

BE Belgium Hϋ Hungary NL Netherlands

BG Bulgaria IT Italy NO Norway

BJ Benin JF Japan RO .Romania

BR Brazil KP Democratic People's Republic SD Sudan

CF Centra] African Republic ofKorea SE Sweden

CG Cong" KR Republic ofKorea SN Senegal

CH Switzerland LI Liechtenstein SU Soviet Union

CM Cameroon LK Sri Lanka TO Chad

DE Germany, Federal Republic of LL' Luxembourg TG Togo

DK Denmark MC Monaco US United States of America fl Finland MG Madagascar

Claims

CLAIMSWhat we claim is:

1. A corrosion-inhibiting formulation for use in water cooling towers comprising water; polyethylene glycol having a molecular weight of between 200 and 20,000; and a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid.

2. A corrosion-inhibiting formulation for use in water cooling towers comprising water; polyethylene glycol having a molecular weight of between 200 and 20,000; hydroxy ethylidene diphosphonic acid; phosphinocarboxylic acid; and tolyltriazole.

3. A corrosion-inhibiting formulation for use in water cooling towers, comprising:

(a) 65-70% water;

(b) 8-12% polyethylene glycol having a molecular weight of between 200 and 20,000; and

(c) 18-27% of two to four additional ingredients selected from the group including hydroxyphosphocarboxylic acid; a copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid; a copolymer of acrylamidomethyl propane sulfonic acid and acrylic acid; tolyltriazole; phosphinocarboxylic acid; and hydroxy ethylidene diphosphonic acid.

4. The formulation set forth in Claim 3, wherein said additional ingredients comprise said polymaleic acid and acrylic acid copolymers of acrylamidomethyl propane sulfonic acid.

5. The formulation set forth in Claim 3, wherein said additional ingredients comprise said copolymer of acrylamidomethyl propane sulfonic acid and polymaleic acid; hydroxyphosphonic acid; and tolyltriazole.

6. The formulation set forth in Claim 3, wherein said additional ingredients comprise hydroxy ethylidene diphosphonic acid; phosphinocarboxylic acid; and tolyltriazole.