JP2001048711A - Cooling water treatment agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject agent highly effective against scale troubles, corrosion troubles and slime troubles in the cooling water system. SOLUTION: This cooling water treatment agent to be used is an chemical agent comprising polyamino acid(s), hydrazine and/or a salt thereof, and as necessary other scale-proofing agent, corrosion-proofing agent and disinfectant (slime-proofing agent); wherein the polyamino acid(s) is e.g. at least one kind selected from polyaspartic acid, polyglutamic acid, and salts thereof, including modified polyamino acids (salts) pref. incorporated with sulfonic acid group and/or sulfonic acid salt group. The above polyamino acid(s) is used at a concentration of 0.1-10 mg/L in the cooling water system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system treating agent, and more particularly to a cooling water treating agent using one or both of polyamino acids and modified polyamino acids which are excellent in biodegradability and are environmentally friendly. About.

[0002]

2. Description of the Related Art The causes of failures in a cooling water system include (a) corrosion damage due to dissolved salts such as dissolved oxygen, chloride ions, and sulfate ions in water, and (b) accumulation of calcium ions in water due to accumulation of calcium ions in water. Scale disturbances such as calcium sulfate and polymerized calcium phosphate, and (c) microorganisms that grow in industrial water proliferate and adhere to walls such as water facilities, causing problems such as a decrease in heat exchange rate and poor running water. There are slime disorders.

[0003] Conventionally, as agents for preventing scale damage and corrosion damage, polymerized phosphates such as sodium pyrophosphate and sodium hexametaphosphate, 1-hydroxyethylidene-1,
Phosphonates such as 1-diphosphonic acid and carboxylic acid-based low molecular weight polymers such as polyacrylic acid are known.
However, among these agents, the polymerized phosphate is hydrolyzed in cooling water to generate orthophosphoric acid, and combines with a hardness component such as calcium in the cooling water to generate a scale such as calcium phosphate.

Accordingly, phosphonic acids and carboxylic acid-based low molecular weight polymers have come to be used as a formulation corresponding to recent high-concentration operation of a cooling water system.

However, in recent years, polyacrylic acid salts, polymethacrylic acid salts, salts of acrylic acid copolymers, and salts of styrene sulfonic acid copolymers have a low problem of eutrophication, but are hardly biodegradable. The impact of use on the environment cannot be ignored.

In order to overcome these drawbacks, biodegradable polymers have recently been proposed as substitutes for polyacrylates, polymethacrylates, salts of acrylic acid copolymers, and salts of styrene sulfonic acid copolymers. .

As one of such biodegradable scale dispersants, JP-A-5-506615 and JP-A-5-506615
No. 506616 discloses polyaspartic acid as an inhibitor of calcium carbonate, calcium phosphate, calcium sulfate and barium sulfate. JP-A-10-36505 discloses a method for producing a modified polyaspartic acid by hydrolyzing an imide ring remaining after an aminosulfonic acid is reacted with an imide ring of polysuccinimide to form an aminosulfonic acid salt and a water treatment. Use as an agent is disclosed. In addition, Tokiohei 8-50
No. 2690 discloses a polyamino acid polymer formed by the reaction of an alkyl, alkenyl and aromatic amine or an alkyl and alkenyl amine with polysuccinimide.

On the other hand, as a use of a polyamino acid corrosion inhibitor, Japanese Patent Application Laid-Open No. 8-510507 discloses a use as a corrosion inhibitor in which an aqueous composition containing a polyamino acid is brought into contact at a pH of 7 or less. ing. Further, JP-A-8-100279 discloses a method for preventing corrosion by a polyamino acid, a builder, and a surfactant.

However, in these prior arts, a method of effectively utilizing polyamino acids and modified polyamino acids as water treatment agents when the cooling water system is operated at high concentration has not been disclosed. there were.

[0010]

DISCLOSURE OF THE INVENTION The present invention uses a polyamino acid and / or a modified polyamino acid which is excellent in biodegradability and is environmentally friendly, and is used for high concentration operation against scale, corrosion and slime disorders in a cooling water system. It is an object of the present invention to provide a cooling water treatment agent that exhibits excellent effects even at times.

[0011]

The present invention has been made in view of the above-mentioned prior art, and as a result of intensive studies on a water treatment agent satisfying the above-mentioned object, it has been found that by blending hydrazine or the like with polyamino acid, polyamino acid and hydrazine can be obtained. Interact with each other to produce a synergistic effect, and completed the present invention.

That is, [1] The present invention provides a water treatment agent for cooling comprising a polyamino acid and hydrazine and / or a salt thereof. [2] The present invention provides that the polyamino acid is a modified polyamino acid. [3] The present invention further provides a cooling water treatment agent according to the above [1], and [3] the present invention further comprises a group consisting of a scale inhibitor other than the polyamino acid, a corrosion inhibitor, and a bactericide (slime inhibitor). [1] The present invention provides the water treatment agent for cooling according to the above [1] or [2], which comprises at least one selected from the group consisting of polyaspartic acid, polyglutamic acid and polyaspartic acid. The present invention provides a water treatment agent for cooling according to any one of the above [1] to [3], which is at least one member selected from the group consisting of salts of [5].
The modified polyamino acid provides a water treatment agent for cooling according to the above-mentioned [2], wherein the modified polyamino acid is a modified polyamino acid into which a sulfonic acid group and / or a sulfonic acid group is introduced. [1] to [5] whose molecular weight is 1,000 to 20,000 in weight average molecular weight.
A water treatment agent for cooling according to any one of the above.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The cooling water treatment agent according to the present invention is a cooling water treatment agent obtained by mixing hydrazine and / or a salt thereof with a polyamino acid, and if necessary, other scale inhibitor, corrosion inhibitor, and sterilizer. It is a water treatment agent for cooling containing at least one selected from agents (slime inhibitors).

The polyamino acid of the present invention is not particularly limited, but is preferably at least one selected from polyaspartic acid, polyglutamic acid, and salts thereof from the viewpoint of high effective functional group concentration. Also,
The polyamino acids include modified polyamino acids. Examples of the modified polyamino acids include polyamino acid derivatives, polyamino acid copolymers, cross-linked polyamino acids, and the like. As the polyamino acids, the effect as a drug can be enhanced by these modified polyamino acids. Of these, modified polyamino acids and / or salts of modified polyamino acids into which sulfonic acid groups and / or sulfonic acid groups have been introduced are preferred in terms of enhancing the effect as a drug, particularly the effect of suppressing scale deposition. This sulfonated polyamino acid can be produced by a known technique. That is, a modified polyaspartic acid can be produced by reacting an aminosulfonic acid with the imide ring of polysuccinimide to form an aminosulfonic acid salt and then hydrolyzing the remaining imide ring.

Non-limiting examples of the counter ion of the polyamino acid and the modified polyamino acid salt include metal salts such as sodium, potassium, lithium, calcium, zinc, barium, cobalt and iron; tetramethylammonium, tetraethylammonium, tetrapropylammonium , Tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, ethyltrimethylammonium, trimethylpropylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyltrimethylammonium, cyclohexyltrimethylammonium, benzyltrimethylammonium,
Ammonium salts such as triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, cyclohexyltriethylammonium, and benzyltriethylammonium; trimethylamine, triethylamine,
Tripropylamine, tributylamine, tripentylamine, trihexylamine, triethanolamine,
Tripropanolamine, tributanolamine, tripentanolamine, trihexanolamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dicyclohexylamine, dibenzylamine, ethylmethylamine, methylpropylamine, Butylmethylamine,
Examples thereof include amine salts such as methylpentylamine, methylhexylamine, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, octylamine, decylamine, dodecylamine, and hexadecylamine.

The amount of the polyamino acid and the modified polyamino acid as the scale inhibitor in the aqueous cleaning agent is not particularly limited, but is 0.1 to 10 mg in the cooling water system.
/ L, preferably 1-5 mg / L
More preferably, it is used at a concentration of Even if a polyamino acid and / or a modified amino acid is used at a concentration exceeding 10 mg / L, no further effect is obtained and the cost is high. Cannot be obtained, which is not preferable. Although the molecular weight of the polyamino acid and the modified polyamino acid is not particularly limited, the weight average molecular weight should be 1,000 to 20,000 from the viewpoint of a balance between a drug effect such as a scale precipitation inhibitory effect and a corrosion inhibitory effect and gelation. , Preferably from 1,000 to 10,000, and more preferably from 2,000 to 5,000. If the molecular weight is less than 1,000, no effect as a drug is obtained, and if it exceeds 20,000, gelation may occur.

The cooling water treating agent of the present invention can further enhance the function of the polyamino acid by adding hydrazine and / or a salt thereof to the polyamino acid.

Examples of the hydrazine and / or a salt thereof in the present invention include hydrazine, hydrated hydrazine, hydrazine sorbitanate, a mixture of hydrazine sorbitanate and hydrazine borate or hydrazine tartrate, and salts thereof. These hydrazines and / or their salts are not limited in amount in the cooling water system,
It is preferably used to be 0.05 to 200 mg / L. Of these, 0.5 to 100 mg / L is more preferred.

The cooling system treating agent according to the present invention may contain, if necessary, a scale inhibitor other than the above polyamino acid, a corrosion inhibitor, and a bactericide other than the above hydrazine and / or its salt (an antislime agent). The effect can be enhanced by one or more additives selected. By mixing or using these drugs in combination, it is possible to enhance the effect as compared with those obtained by simply mixing a polyamino acid and hydrazine and / or a salt thereof.

The scale inhibitor other than the polyamino acid is not particularly limited, but examples thereof include hydroxyethylidene diphosphonic acid, phosphonobutanetricarboxylic acid, nitrilotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, and aminotriamine. Methylenephosphonic acid, bisaminomethyldicyclopentadienetetramethylenephosphonic acid, bisaminomethylbicycloheptanetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, hydroxyethylethylenediaminetrimethylenephosphonic acid, pentaethylenehexamineoctamethylenephosphonic acid, hexamethylenediamine Tetramethylene phosphonic acid, a phosphonomethylated polyalkylene polyamine having a molecular weight of about 100,000 or more, and Phosphonic acid and / or its salts such et salt. Salts of these compounds include alkali metal salts and ammonium salts. These may be used alone or as a mixture. Of these, one or more of hydroxyethylidene diphosphonic acid, hydroxyethylenediphosphonate, phosphonobutanetricarboxylic acid, and phosphonobutanetricarboxylate are preferably used in terms of effect.

These scale inhibitors are preferably used in the cooling water system so as to have a concentration of 0.05 to 20 mg-P / L, more preferably 0.2 to 5.0 mg-P / L. preferable.

In addition, low molecular weight acrylic acid polymers such as sodium polyacrylate, polysodium methacrylate, copolymer salts of acrylic acid and methacrylic acid, salts of copolymers of ethylene and maleic acid, and copolymer salts of styrene sulfonic acid and maleic acid , Tannins, lignins and starches.

Examples of the corrosion inhibitor include polymeric phosphoric acid and / or a salt thereof, and a non-phosphate-based corrosion inhibitor. Examples of the polymerized phosphoric acid and / or a salt thereof include one or a mixture of two or more selected from tripolyphosphoric acid, tripolyphosphate, hexametaphosphate, and hexametaphosphate. As these phosphates, it is preferable to use alkali metal salts. The amount of the corrosion inhibitor is 0.1 to 5 in the cooling water system.
0 mg / L is preferably used.
More preferably, it is used so as to be 30 mg / L. Examples of the non-phosphate-based corrosion inhibitor include a water-soluble cationic polymer. Examples of the water-soluble cationic polymer include polyacrylamide, polymethacrylamide, a decomposed product of these Hoffman, or polyacrylamide, a decomposed Hofmann product of a partially decomposed product of polymethacrylamide, or polyacrylamide, a Hoffman product of polymethacrylamide. Acrylamide polymer such as partially decomposed product of decomposed product; poly [2-hydroxyethylene (dimethylimino) ethylene (dimethylimino) methylene chloride] or poly [oxyethylene (dimethylimino) ethylene (dimethylimino) ethylene chloride]
Examples of such products include reaction products of N, N, N ', N'-tetraethylenediamine and epichlorohydrin or dichloroether. These water-soluble cationic polymers are preferably used in a cooling system so as to be 0.1 to 50 mg / L, more preferably 1 to 50 mg / L.
It is preferably used to be 30 mg / L.

An aliphatic aldehyde containing a copolymer of a phenolic compound and an aliphatic aldehyde; a molybdate such as sodium molybdate or potassium molybdate which acts as an anticorrosive of an oxide film type on iron;
Benzotriazoles, such as 1,2,3-benzotriazole, tolyltriazole, and 1,2-benzoisothiazolin-3-one, which exhibit an excellent corrosion inhibiting effect when combined with metals, particularly copper, and act as a cathode-type inhibitor Zinc-containing compounds such as zinc sulfate and zinc nitrate;
Biocides such as isothiazolone are exemplified. These are preferably used in a concentration range that exhibits an effect in the cooling water system.
It is preferably used so as to be 000 ppm.

The above-mentioned polyamino acid and / or modified polyamino acid, hydrazine and / or a salt thereof, and optionally used other scale inhibitors, corrosion inhibitors, and bactericides (antislime agents) are selected. One or more additives may be incorporated into one liquid as needed, or may be divided into several liquids and added to the cooling water system. The concentration of the drug is preferably used in the cooling water system so as to be 100 to 1000 ppm.

The method of use in the cooling water system is preferably selected for each applicable cooling water system. More specifically, it is preferable to select for each of the open circulation cooling water system, the closed circulation cooling water system, and the once-through cooling water system. Among them, for example, in an open circulation type cooling water system, a high concentration operation is performed by adjusting the concentration multiple such as the total alkalinity and pH of the circulating cooling water to reduce the amount of blow water to reduce the amount of used water and to minimize the necessary chemicals. Performing the treatment is preferable in reducing the effect on the environment.

[0027]

The present invention will be described more specifically with reference to the following examples. In addition, various properties of the polymer composition were measured by the following methods. (Example 1) Using a model machine of an open circulation type cooling water system, each compound used in the present invention was prepared and tested in accordance with a mixture prepared in advance according to a combination table shown in Table 1.
These treating agents were adjusted to a concentration of 80 ppm in the cooling water system. The model machine has a retained water volume of 100 L, a circulating water volume of 400 L / h, an evaporative water volume of 4.5 L / h, and a scattered water volume of 0.4 L / h.
2 L / h, a heat exchanger (SUS plate) for measuring scale and slime amount was provided in the system, and the outlet temperature was 45
C., and a mild steel test plate was inserted after the outlet. A bypass is provided in the system, and the temperature of the aqueous humor of the cooling tower and the water supply temperature are 35 ° C
Was adjusted. Test water having a calcium hardness of 50 ppm was used. 300ml of slime mainly composed of zooglare diatoms at the start of the test to promote the generation of slime
Was introduced. The test was performed for 30 days for each test, and the concentration ratio of the cooling water was set to 5. The scale amount, slime amount and corrosion weight loss after the test were measured. (Examples 2 to 5) In the same manner as in Example 1, the composition of the treatment agent was changed as shown in Table 1, and the adhesion on the heat transfer surface and the amount of corrosion were measured. (Comparative Example 1) For comparison, the scale adhesion and the amount of corrosion were measured when no aqueous cleaning agent was used. (Comparative Example 2) As in Example 1, the composition of the treatment agent was changed as shown in Table 1, and the adhesion on the heat transfer surface and the amount of corrosion were measured.

[0028]

[Table 1]

[0029]

[0030]

The cooling water treatment agent of the present invention is extremely effective against scale obstacles, slime obstacles, and corrosion obstacles in the cooling water system. The effect is further improved by the addition of other scale inhibitors.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 532 C02F 1/50 532E 532J 540 540B 5/00 620 5/00 620B 5/10 620 5 / 10 620Z 5/12 5/12 (72) Inventor Shigeki Ideguchi 4-17 Jonanmachi, Izumiotsu-shi, Osaka (72) Inventor Yaya Kato 3-3-4-610 F-term, Kamotanidai, Sakai-shi, Osaka (Reference) 4H011 AA02 BB04 BB06 BB07 BB19 DD01 DE14 DF04 DG03 DG11 DH06 DH11 DH29

Claims (6)

[Claims] 1. A cooling water treatment agent comprising a polyamino acid and hydrazine and / or a salt thereof. 2. The cooling water treatment agent according to claim 1, wherein the polyamino acid is a modified polyamino acid. 3. The method according to claim 1, further comprising at least one selected from the group consisting of a scale inhibitor other than the polyamino acid, a corrosion inhibitor, and a bactericide (slime inhibitor) other than the hydrazine and / or its salt. Or the water treatment agent for cooling according to 2. 4. The polyamino acid is polyaspartic acid,
The water treatment agent for cooling according to any one of claims 1 to 3, which is at least one selected from the group consisting of polyglutamic acid and salts thereof. 5. The cooling water treatment agent according to claim 2, wherein the modified polyamino acid is a modified polyamino acid into which a sulfonic acid group and / or a sulfonic acid group has been introduced. 6. The cooling water treatment agent according to claim 1, wherein the polyamino acid has a molecular weight of 1,000 to 20,000 in weight average molecular weight.