JPH07256266A - Method for water treatment in cooling water system - Google Patents

Abstract

PURPOSE:To prevent slime damage, scale damage, corrosion damage, etc., in a cooling water system by using a water-soluble cationic polymer, a halogenated aliph. nitroalcohol and a phosphonic acid or its salt and/or a carbonic acid-type low mol.wt. polymer. CONSTITUTION:When water treatment is performed in an open-type circulation- type cooling water system wherein slime damage, scale damage, corrosion damage and bacteria of Legionella genus occur, 1-50ppm water-soluble cationic polymer, 1-50ppm halogenated aliph. nitroalcohol and 1-50ppm phosphonic acid or its salt and/or 1-50ppm carbonic acid-type low mol.wt. polymer are incorporated into either blow water, feeding water or stored water in the cooling water system. In addition, in this case, as the water-soluble cationic polymer, a compd. of formula I or II is used. In addition, as the halogenated aliph. nitroalcohol, 2-bromo-2-nitropropane diol-1,3 is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a water treatment method for a cooling water system. More specifically, slime disorders, scale disorders,
The present invention relates to a water treatment method applied to an open circulating cooling water system in which corrosion damage and bacteria of the genus Legionella are generated.

[0002]

2. Description of the Related Art In recent years, a large amount of industrial water has been required with the development of the chemical industry and other industries. As industrial water sources, in addition to industrial tap water, seawater, lake water, swamp water, river water, etc. are used. Various microorganisms grow in these industrial waters, and among these microorganisms, many continue to proliferate due to the water quality and the environment in which they exist and cause various disorders.

[0003] For example, when used as cooling water, microorganisms inhabiting water multiply and grow on the walls of water facilities to form slime, which lowers the heat exchange rate and causes poor running water. A failure occurs. In particular, when circulating water, in the case of an open type using an open type cooling tower, etc., the circulating water is forcibly aerated and comes into contact with air in a part of the system, and it is exposed to sunlight. Promotes the reproduction of aerobic microorganisms such as bacteria and algae. Similar obstacles have also occurred in cooling water systems such as air conditioners in buildings and factories, and small cooling towers installed in cooling and heating facilities. In general-use water systems, especially cooling water systems, in addition to slime damage, calcium carbonate and calcium sulfate can be corroded due to corrosion damage due to dissolved salts such as dissolved oxygen, chlorine ions, and sulfate ions in water, and accumulation of calcium ions in water. , And scale disorders such as calcium phosphate occur with the use of polymerized phosphate-based anticorrosives. In particular, these obstacles have become more serious with the recent highly concentrated operation of the cooling water system.

By the way, recently, Legionella bacteria detected in such a cooling water system has become a serious problem. Legionella is a gram-negative elongated bacterium, its optimum growth temperature is 35 ° C to 36 ° C, which matches the temperature of cooling water, and is a symbiotic bacterium that obtains a nutrient source from algae, heterotrophic bacteria, etc. Such a cooling water system in which microorganisms can easily propagate provides a suitable growth environment. When the cooling water in which the Legionella bacteria have propagated is scattered from the cooling tower, or in air conditioning equipment, the splash of cooling water contaminates the air and enters the air conditioning facility from the outside air intake port, causing Legionella bacteria contamination of the indoor air. , Known to infect the human body. Infections caused by Legionella bacteria are called local military illnesses, and they may cause symptoms similar to pneumonia, which may even lead to death, and countermeasures are required.

Conventionally, as chemicals for preventing slime disorders, inorganic and organic chlorine compounds such as liquid chlorine, sodium hypochlorite, and chlorinated isocyanuric acid, and quaternary ammonium salts have been known. However, chlorine compounds are not safe to use because they are safe and corrosive to metals, and under the recent conditions of highly concentrated cooling water system operation, the pH of the cooling water is on the alkaline side, resulting in poor effects. The situation is difficult. In addition, the quaternary ammonium salt is also rarely used because it has a problem that the effect is offset by reacting with a carboxylic acid low molecular weight polymer used in combination as a foaming agent, an anticorrosive agent and a scale inhibitor in water. Is.

In recent years, instead of these, drugs such as hydrazine, isothiazolones, and halogenated aliphatic nitroalcohols have been widely used. However, these drugs are also easily decomposed in the water system and their effects are not stable. Further, there are drawbacks such as high skin irritation, difficult handling, and high price.

Among the above-mentioned agents, agents such as isothiazolones and halogenated aliphatic nitroalcohols are known as effective bactericides against Legionella bacteria. However, when applied to an actual cooling water system, these drugs require a considerably high concentration in order to sufficiently exert the effect as a bactericidal agent, and the effects are poor in sustainability and the drug is continuously applied at a high concentration. It has the drawback that it has to be added to.

Further, as a conventional agent for preventing scale damage and corrosion damage, polymeric phosphates such as sodium pyrophosphate and sodium hexametaphosphate, phosphonic acids such as 1-hydroxyethylidene-1,1-diphosphonic acid, and polyacrylic acid. Carboxylic acid low molecular weight polymers such as soda are known.

It is also well known that a divalent metal salt such as a water-soluble zinc salt is used in combination in order to enhance the effect of preventing corrosion of steel materials. Further, an azole compound such as benzotriazole is often used to prevent corrosion of steel, copper or alloy materials thereof.

However, the polymerized phosphate is hydrolyzed in cooling water to form orthophosphoric acid and is combined with hardness components such as calcium in the cooling water to produce scales such as calcium phosphate. Water-soluble zinc salts also have the problem that zinc hydroxide and zinc phosphate scales easily form in cooling water, and these applications are applicable to low-concentration operation systems with a short residence time in the cooling water system and a pH of about 8 or less. Is valid only in.

Therefore, it is general to use a phosphonic acid or a carboxylic acid-based low molecular weight polymer as a formulation capable of coping with the recent highly concentrated operation of a cooling water system. However, the anticorrosion effect of these chemicals is relatively weak and not only difficult to apply to low concentration operation system, but also the effect is insufficient even in high concentration operation cooling water system where pH is alkaline and the corrosiveness is relatively moderated. Is.

Further, the scale-preventing effect of phosphonic acids and carboxylic acid-based polymers is found to have some effect on the calcium carbonate scale generally generated in cooling water systems, but the effect gradually increases as the coexisting silica ion concentration increases. There is a drawback to decrease. Further, it often has no effect on a silicate scale in which silica and magnesium or calcium are combined. Therefore, even when the cooling water system is highly concentrated, it is common to set and control the concentration factor so that the silica concentration in the water does not exceed about 200 ppm.

In view of the above circumstances, the current cooling water system water treatment method appropriately selects a chemical agent according to the operation management conditions such as the quality of cooling water and makeup water, the multiple factor of concentration of cooling water, and the silica concentration in the cooling water. The actual situation is to set the operating conditions so that the value does not exceed about 200 ppm.

[0014]

DISCLOSURE OF THE INVENTION The present invention always has a stable effect on slime damage, scale damage, corrosion damage and generation of Legionella bacteria in a cooling water system regardless of the quality of the cooling water or the concentration multiple of the cooling water system. It is to provide a water treatment method that exerts the above.

[0015]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies on a water treatment method which satisfies the above-mentioned object, and have found that a water-soluble cationic polymer, a halogenated aliphatic nitroalcohol and a phosphonic acid or a salt and / or a carvone thereof. It was found that it is effective to use an acid-based low molecular weight polymer, and it is quite unexpectedly found that the respective compounds interact with each other to produce a synergistic effect.

That is, in the present invention, (A) a water-soluble cationic polymer in an amount of 1 to 50 ppm, (B) a halogenated aliphatic nitroalcohol in an amount of 1 to 50 ppm in any of blow water, makeup water, and retained water in a cooling water system, (C) A water treatment method for an open-type circulating cooling water system, which comprises adding 1 to 50 ppm of phosphonic acid or a salt thereof and / or 1 to 50 ppm of a carboxylic acid-based low molecular weight polymer.

The water-soluble cationic polymer used in the present invention is N, N, N ', N'-tetraethylenediamine represented by the following general formulas (1) and (2) and epichlorohydrin or dichloro. A polymer composed of a reaction product with ether, specifically poly [2-hydroxyethylene (dimethylimino) ethylene (dimethylimino) methylene chloride] or poly [oxyethylene (dimethylimino) ethylene (dimethylimino) ethylene. Chloride].

[0018]

[Chemical 3]

These polymers are disclosed in Japanese Examined Patent Publication No. 53-233.
No. 77 and Japanese Patent Publication No. 55-49042 disclose that they are effective as algaecides, and it can be predicted that these polymers will be effective for slime treatment. In fact, we have proposed the previously proposed water-soluble cationic polymer, phosphonic acid or its salt and / or
A multifunctional water treatment agent comprising a mixture of a carboxylic acid low molecular weight polymer as an active ingredient (Japanese Patent Laid-Open No. 5-76)
856) showed that the above polymers were effective for slime treatment.

The multifunctional water treatment agent in JP-A-5-76856 has a point that the scale preventing effect is improved and the anticorrosion effect of the copper material is improved by using the above-mentioned respective components as a mixture agent. It has an excellent feature in that it does not require a copper anticorrosive such as an azole compound.

However, the water treatment agent composed of the admixture disclosed in JP-A-5-76856 has almost no effect on Legionella bacteria, and is particularly effective in a cooling water system such as a low concentration operation which is relatively corrosive. The anticorrosion effect on steel materials cannot be expected so much. It was also found that when the cooling water system is subjected to extremely severe high concentration operation such as non-blow operation, the scale prevention effect is not sufficient.

On the other hand, the halogenated aliphatic alcohol used in the present invention is a compound represented by the following general formula (3).

[0023]

[Chemical 4]

(In the formula, R ¹ is a hydrogen atom, a halogen atom, a lower alkyl group or a hydroxy lower alkyl group, R ² is a hydrogen atom or a lower alkyl group, and X is a halogen atom.)

Specific examples of the halogenated aliphatic alcohol represented by the above general formula (3) include 2
-Chloro-2-nitroethanol, 1-chloro-1-
Nitropropanol-2, 3-chloro-3-nitrobutanol-2, 2-chloro-2-nitrobutanediol-1,3, 1-chloro-1-nitrobutanol-
2, 2-chloro-2-nitrobutanol, 2-chloro-2-nitropentanol-3, 2,2-dichloro-2-nitroethanol, 2-chloro-2-bromo-
2-nitroethanol, 3-chloro-3-nitro-pentanediol-2.4, 4-chloro-4-nitrohexanol-3, 2-bromo-2-nitroethanol, 2-bromo-2-nitropropanol, 2 -Bromo-2-nitropropanediol-1,3,2-bromo-2-nitrobutanediol-1,3,3-bromo-3-nitropentanediol-2,4,2,2-dibromo-2-nitro -Ethanol, 4-bromo-4-
Nitrohexanol-3, 2-Fluoro-2-nitroethanol, 2-Fluoro-2-nitrobutanediol-1,3, 3-Iodo-3-nitrobutanol-
2, 2-fluoro-2-chloro-2-nitroethanol, 2-iodo-2-bromo-2-nitroethanol and the like can be mentioned. Among these compounds, 2-bromo-2-
Nitropropanediol-1,3 (hereinafter referred to as bronopol) is particularly suitable.

The halogenated aliphatic nitroalcohols used in the present invention are known as slime treating agents and agents having a bactericidal action against Legionella bacteria. In particular, bronopol is known to have a clear bactericidal activity at a concentration of several tens of ppm in a pure culture system targeting Legionella. However, according to the study by the present inventors, when bronopol was added to an actual cooling water system, almost no bactericidal action was observed at a concentration of several tens ppm,
It is necessary to add an amount of at least 100 ppm. However, halogenated aliphatic nitroalcohols such as bronopol are expensive compounds, and it is economically problematic to add them in an amount such that the concentration is as high as several 100 ppm, and it has been difficult to put them into practical use.

However, when the halogenated aliphatic nitroalcohol is used in combination with another chemical as one component of the chemical in the water treatment method of the present invention, compared with the case where the halogenated aliphatic nitroalcohol is used alone, it is completely different. An unexpected and dramatic improvement in effect was observed.

That is, although the other components in the present invention have no bactericidal or antibacterial action against the Legionella bacterium by themselves, the halogenated aliphatic nitroalcohol alone has almost no effect on the halogenation at a low concentration. It was found that coexistence of the aliphatic nitroalcohol with other drug components exhibits excellent bactericidal and antibacterial actions against Legionella.

Further, phosphonic acids and carboxylic acid-based low molecular weight polymers have relatively low anticorrosion effects, but even if the water quality is highly corrosive, such as low-concentration operating system water systems, they themselves have almost no anticorrosion effect on steel. It was found that a stable anticorrosive effect can be obtained by coexisting a halogenated aliphatic nitroalcohol that does not exist.

Further, the halogenated aliphatic nitroalcohol itself does not have the scale preventive ability, but by using a small amount of the halogenated aliphatic nitroalcohol in combination with other agents, the scale preventive ability is further improved. It was also found that a good scale preventing effect is exhibited even under severe high-concentration operation conditions such as non-blow operation.

As the phosphonic acid or its salt and the carboxylic acid type low molecular weight polymer used in the present invention, those conventionally used as a cooling water type anticorrosion agent and scale inhibitor can be applied as they are, but preferred compounds. Specifically, phosphonic acids or salts thereof include phosphonocarboxylic acids such as aminotrismethylenephosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid. Acids and salts thereof, especially sodium salts and the like.

As the carboxylic acid low molecular weight polymer, copolymers of acrylic acid and other monomers such as poly (meth) acrylic acid soda and (meth) acrylic acid acrylamide copolymer, polymaleic anhydride, Examples thereof include maleic anhydride and other copolymers such as maleic anhydride-isobutylene copolymer, and further acrylic acid-maleic anhydride copolymer.

Further, a carboxylic acid-based polymer containing a phosphinic acid represented by the following general formula (4) or a salt thereof, that is, bis (poly-2-carboxyethyl) phosphinic acid or a salt thereof (specifically, Sodium salt) can also be used.

[0034]

[Chemical 5]

As these carboxylic acid type polymers, those having a molecular weight of 500 to 50,000 are generally used.

In the present invention, the amount of each compound added to the cooling water system is (A) water-soluble cationic polymer 1
˜50 ppm, (B) halogenated aliphatic nitroalcohol 1 to 50 ppm, (C) phosphonic acid or salt thereof 1 to
50 ppm, (D) carboxylic acid-based low molecular weight polymer 1 to
50 ppm, preferably 2 to 20 ppm
Is. The concentration of each compound in the cooling water system is 2
If added in an amount of less than ppm, the performance as a water treatment agent may be insufficient, and normally, in the case of most cooling water systems, the desired effect is sufficiently obtained by adding an amount of 20 ppm in water.

In the present invention, the standard amount of water for adding each compound is cooling water blow water, makeup water,
It is one of the owned water. In the open circulation cooling water system,
There is a loss due to the evaporation of circulating water in the cooling tower and the dissolved solids in the water are concentrated. Generally, a part of circulating water is forcedly blown to prevent excessive concentration of dissolved solids. Therefore, makeup water corresponding to the amount of evaporated water and the amount of blown water is supplied. Make-up water amount = Evaporated water amount + Blow water amount (Spray blow water amount + Forced blow water amount) Concentration factor = Make-up water amount / Blow water amount Which of the standard water amounts to select when adding is determined by the operating conditions of the cooling water system and the water balance described above It should be decided in consideration of.

The method of adding to the blow water is suitable for a low to medium concentration operation system in which the concentration factor of the cooling water system is less than 5. The method of adding to the makeup water is suitable for a highly concentrated operation system in which the concentration factor of the cooling water system is 5 or more. In the highly concentrated operation system, although the amount of blow water is extremely small, dissolved solids and microorganisms in circulating water are likely to accumulate and cause troubles. The method of addition is optimal. The method of adding to the retained water is not suitable for the operation management of the cooling water system, and is suitable when the chemical is intermittently added and treated.

As a method of adding each compound to the cooling water system, each compound may be added individually to the cooling water system or may be preliminarily compounded and added as a mixture. Usually, it is preferable to use it as a premixed mixture because it is convenient in terms of work. When used as an admixture, the compounding ratio may be such that each compound is added to water in the above-mentioned concentration range, and generally, 1 to 20% by weight of a water-soluble cationic polymer and a halogenated fat are used. The range is 1 to 20% by weight of group nitroalcohol, 1 to 20% by weight of phosphonic acid or salt thereof, and / or carboxylic acid-based low molecular weight polymer. The balance may be usually mixed with water as a solvent, but a hydrophilic solvent such as alcohol may be used.

When each compound is added individually to the cooling water system, it is most preferable that each compound is added simultaneously, but it is not always necessary.

The desired effect can be obtained by adding each compound at any time as long as the effective amount of each compound can be considered to exist in consideration of the water balance in the cooling water system. can get.

The water treatment method according to the present invention can prevent various obstacles in the cooling water system, but it is possible to further add conventionally used slime treatment agents and anticorrosive agents, if desired. Examples of such agents include isothiazolone compounds as slime treating agents and azole compounds such as benzotriazole as anticorrosion agents for copper.

[0043]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 An admixture pre-blended with each compound used in the present invention was prepared and tested in a model plant of an open type circulating cooling water system.

In this example, N, N, N ', N'-represented by the general formula (1) was used as the water-soluble cationic polymer.
A reaction product of tetramethylethylenediamine and epichlorohydrin (molecular weight 6,000, hereinafter referred to as compound A) and N, N, N ', represented by the general formula (2),
Reaction product of N'-tetraethylenediamine and dichloroethyl ether (molecular weight 5,000, compound B)
Was used. Bronopol was used as the halogenated aliphatic nitroalcohol.

Mixture 1 Compound (A) (50% aqueous solution) 20 parts by weight Bronopol 10 parts by weight 1-hydroxyethylidene-1,1-diphosphonic acid (60% aqueous solution) 20 parts by weight Water 50 parts by weight Total 100 parts by weight

Admixture 2 Compound (A) (50% aqueous solution) 20 parts by weight Bronopol 10 parts by weight Bis (poly-2-carboxyethyl) phosphinic acid 20 parts by weight (molecular weight 1200, 40% aqueous solution) Water 50 parts by weight Total 100 Parts by weight

Admixture 3 Compound (A) (50% aqueous solution) 20 parts by weight Bronopol 10 parts by weight 1-hydroxyethylidene-1,1-diphosphonic acid (60% aqueous solution) 10 parts by weight Maleic anhydride-acrylic acid copolymer 10 parts by weight (Molecular weight 1500, 40% aqueous solution) Water 50 parts by weight Total 100 parts by weight

Admixture 4 Compound (B) (50% aqueous solution) 20 parts by weight Bronopol 10 parts by weight Polymaleic anhydride (molecular weight 900,50% aqueous solution) 20 parts by weight Water 50 parts by weight Total 100 parts by weight

Mixture 5 Compound (B) (50% aqueous solution) 20 parts by weight Bronopol 10 parts by weight 2-phosphonobutane-1,2,4-tricarboxylic acid (50% aqueous solution) 20 parts by weight Water 50 parts by weight Total 100 parts by weight

Mixture 6 Compound (B) (50% aqueous solution) 20 parts by weight Bronopol 10 parts by weight Aminotrismethylenephosphonic acid 10 parts by weight Maleic anhydride / isobutylene copolymer 10 parts by weight (molecular weight 1800, 50% aqueous solution) Water 50 parts by weight Total 100 parts by weight

The model plant has a holding water volume of 60 liters, a circulating water volume of 400 l / hr, and an evaporated water volume of 4.8 l / hr.
hr, the amount of splashed water was 0.2 l / hr, and a heat exchanger (SUS304 for measuring slime and scale) was used in the system.
The heat transfer area is 0.707 m ² ) and the outlet temperature is 45
℃, after the heat exchanger outlet mild steel (JIS G31
41 SPCC-B) and copper (JIS H3104)
A column for measuring the amount of corrosion, in which a DCuP ₁ ) test piece was inserted, was provided.

Further, a bypass was provided in the system, and the return water temperature of the cooling tower was adjusted to 37 to 38 ° C and the water supply temperature was adjusted to 35 ° C.

In order to promote the generation and adhesion of slime, 400 ml of slime mainly containing zooglare and diatom taken from a factory cooling tower at the start of the test (sedimentation volume after 30 minutes, equivalent to dry weight of about 10 g) was added. .

The test was carried out for 20 days for each test, and the cooling water concentration factors were 2 (low concentration), 5 (medium concentration) and non-blow (high concentration) without forced blow.

The drug efficacy was evaluated by measuring the amount of deposits on the heat exchanger tube after 20 days and determining the deposition rate (mcm: mg / cm).
^{It was} converted and expressed as ( ^February / month), and the ignition loss ratio in the deposit was also measured to be used as a guideline for the slime deposit amount. Further, the corrosion weight loss of mild steel and copper pieces after 20 days was measured and shown as a corrosion rate (mdd: mg / 100 m ² · month). Further, after 10 days and 20 days, cooling water was sampled to measure the number of viable Legionella bacteria.

The raw water used had a pH of 7.7.
Electric conductivity 204μs / cm, M alkalinity 82ppm,
The total hardness was 81 ppm, the calcium hardness was 48 ppm, the sulfate ion was 24 ppm, the chlorine ion was 12 ppm, and the dissolved silica was 45 ppm, and the water quality had a particularly high dissolved silica concentration.

The method of adding the admixture under each operating condition was as follows. The test results are shown in Table-1 and Table-2.

Concentration factor Makeup water amount (l / hr) Blow water amount (l / hr) Mixing agent addition method 2 10 5 Continuously add 50 ppm to the blow water amount ──────────────── ─────────────────── 5 6.25 1.25 Continuous addition of 50 ppm to the amount of makeup water ─────────────── ─────────────────── Non-blowing 5 0.2 Continuous addition of 50ppm to the amount of makeup water

[0060]

[Table 1]

[0061]

[Table 2]

Comparative Example 1 In the same manner as in Example 1, a mixture of a water-soluble cationic polymer and phosphonic acid or its salt and / or carboxylic acid type polymer, bronopol and phosphonic acid or its salt and / or carboxylic acid type. The polymer admixture was prepared and tested.

Admixture 7 Compound (A) (50% aqueous solution) 40 parts by weight 1-Hydroxyethylidene-1,1-diphosphonic acid 20 parts by weight (60% aqueous solution) Water 40 parts by weight Total 100 parts by weight

Admixture 8 Compound (B) (50% aqueous solution) 40 parts by weight Polymaleic anhydride (molecular weight 900,50% aqueous solution) 20 parts by weight Water 40 parts by weight Total 100 parts by weight

Admixture 9 Bronopol 20 parts by weight 1-Hydroxyethylidene-1,1-diphosphonic acid 10 parts by weight Maleic anhydride-acrylic acid copolymer 10 parts by weight (molecular weight 1500 50% aqueous solution) 60 parts by weight Total 100 parts by weight Department

Mixture 10 Bronopol 20 parts by weight 2-phosphonobutane-1,2,4-tricarboxylic acid 20 parts by weight (50% aqueous solution) water 60 parts by weight Total 100 parts by weight The results are shown in Tables 3 and 4.

[0067]

[Table 3]

[0068]

[Table 4]

Example 2 In the same manner as in Example 1, each compound used in the present invention was individually added and tested. The addition was continued for 20 days by adopting a method in which each compound was added once at a time to a predetermined concentration for 60 liters of retained water once every 12 hours. The added compound and the addition amount are shown in Table-5 (A), and the results are shown in Table-5 (B) and (C).

[0070]

[Table 5]

[0071]

[Table 6]

[0072]

[Table 7]

Example 3 Each compound used in the present invention was individually added and tested in the same manner as in Example 2. However, in this example, the addition method of each compound was different. The added compounds and the addition method are shown in Table-6 (A) and Table-6 (B), and the results are shown in Table-6 (C) and Table-6 (D).

[0074]

[Table 8]

[0075]

[Table 9]

[0076]

[Table 10]

[0077]

[Table 11]

[0078]

INDUSTRIAL APPLICABILITY The cooling water system water treatment method of the present invention is not limited to that each compound used exerts the function originally possessed, but due to the remarkable synergistic effect based on the interaction,
It has the effect of preventing slime, scale, corrosion damage and generation of Legionella bacteria with an extremely low concentration regardless of fluctuations in the cooling water quality and operating conditions of the cooling water system, and its industrial utility value is extremely high. .

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location A01N 33/12 101 (72) Inventor Yufumi Goto 2-5-2 Marunouchi 2-chome, Chiyoda-ku, Tokyo Sanryo Gas Chemical Co., Ltd.

Claims (4)

[Claims] 1. (A) Water-soluble cationic polymer 1 to 5 for any of blow water, makeup water, and retained water of a cooling water system
0 ppm, (B) halogenated aliphatic nitro alcohol 1
˜50 ppm, (C) Phosphonic acid or salt thereof 1-50
ppm and / or carboxylic acid based low molecular weight polymer 1
A water treatment method for an open-type circulating cooling water system, characterized in that ˜50 ppm is added. 2. A water-soluble cationic polymer represented by the general formula (1):
The water treatment method according to claim 1, which is a compound represented by (2). [Chemical 1] 3. The water treatment method according to claim 1, wherein the halogenated aliphatic nitro alcohol is a compound represented by the general formula (3). [Chemical 2] (In the formula, R ¹ represents a hydrogen atom, a halogen atom, a lower alkyl group or a hydroxy lower alkyl group, R ² represents a hydrogen atom or a lower alkyl group, and X represents a halogen atom.) 4. The water treatment method according to claim 1, wherein the halogenated aliphatic nitroalcohol represented by the general formula (3) is 2-bromo-2-nitropropanediol-1,3.