JP2010173994A - Multifunctional water treatment agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multifunctional water treatment agent applied to a recirculation cooling water system where slime trouble, corrosion trouble, and scale trouble may occur. <P>SOLUTION: The multifunctional water treatment agent includes a hydrazide compound, a carboxylic acid-based low-molecular-weight polymer, and an azole compound as active components. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a multifunctional water treatment agent. More specifically, the present invention relates to a multifunctional water treatment agent applied to a circulating cooling water system in which slime failure, corrosion failure and scale failure occur.

In recent years, with the development of industry, a large amount of industrial water has become necessary. In addition to industrial water, seawater, lake water, river water, groundwater, and the like are used as water sources for water.
Microorganisms inhabit these irrigation waters, and there are many microorganisms that cause further damages depending on the water quality and environment in which they exist and cause various obstacles. For example, when used as cooling water, microorganisms that live in the water grow and grow on the walls of water supply facilities to form slime, which causes problems such as reduced heat exchange rate and poor running water. .

  In particular, in the case of an open type using an open type cooling tower in the circulation use of water, bacteria and algae etc. are produced by forced aeration of the circulating water in part of the system, contact with air, and irradiation with sunlight. Breeding of microorganisms is encouraged. Similar obstacles have also occurred in cooling water systems in which small cooling towers are installed in air conditioning and cooling / heating facilities in buildings and factories. Moreover, in general water systems, especially cooling water systems, in addition to slime damage, corrosion damage caused by dissolved salts such as dissolved oxygen, chlorine ions, and sulfate ions in water, and accumulation of calcium ions in water cause accumulation of calcium carbonate and calcium sulfate. And scale disorders such as calcium phosphate occur with the use of polymeric phosphate-based anticorrosives. In particular, these obstacles are becoming more and more serious with the recent high concentration operation of the cooling water system.

  However, in general, a slime treatment agent, an anticorrosive agent, and a scale inhibitor have been added individually to the water for effective use of these effects. This is because anti-slime agent, anti-corrosion agent, anti-scaling agent, etc. are used as a single agent, and there are many cases where it is not possible to achieve an effect that can sufficiently satisfy the functions of each, and depending on the type of anti-slime treatment agent. Or when mixed with a scale inhibitor, precipitation occurs, or it is difficult to be formed into a single agent due to decomposition and difficulty in compounding. However, such a method is extremely complicated for the manager to manage, and there has been a demand for a drug that can treat various obstacles to water with a single agent.

  Under such circumstances, an open-type cooling water system failure inhibitor comprising a mixture of hydrazine as a slime inhibitor and containing an anticorrosive agent and a scale inhibitor is proposed as a multifunctional water treatment agent and put into practical use. (See Patent Document 1). However, the use of hydrazine as a slime inhibitor for multifunctional water treatment agents may be inefficient due to decomposition in aqueous systems, and hydrazine is designated as a target substance for PRTR. It is considered that there is a possibility of adverse effects on living organisms, and there is a strong demand for avoiding the use of hydrazine.

  On the other hand, slime suppression technology using chloroisothiazoline complex compounds such as 5-chloro-2-methylisothiazolin-3-one (hereinafter referred to as CMT) metal salt complex and halogenated aliphatic nitroalcohol as a slime suppression component has also been proposed and put into practical use. It has become. This is a technology that utilizes a synergistic effect in combination with a halogenated aliphatic nitroalcohol in a cooling water system in which slime is easy to propagate, because the CMT metal salt complex alone may decompose quickly and may not be effective enough ( Patent Document 2). However, even when the CMT metal salt complex and the halogenated aliphatic nitroalcohol are used in combination, the CMT metal salt complex becomes unstable in the circulation cooling water system with advanced concentration, and the slime suppression performance is reduced. In addition, CMT metal salt complex is a strong skin irritant and is very dangerous when handled. It itself has corrosiveness to iron and copper materials and contains anticorrosive ingredients such as azoles and carboxylic acid-based low molecular weight polymers. Even in such a part where a sufficient flow rate cannot be obtained, such as the cooling tower lower water tank, the anticorrosion performance is lowered.

  In the prior art described above, a carboxylic acid-based low molecular weight polymer is usually used as an anticorrosive component for iron materials. The anti-corrosion mechanism of carboxylic acid-based low molecular weight polymers is the formation of insoluble salts and precipitated films formed by carboxylic acid-based low molecular weight polymers and calcium ions in water on the metal surface by concentrating the cooling water to a concentration factor of about 5 times. Is due to. However, when the cooling load is low at the start of chiller operation and before the end of the chiller operation, in facilities where the concentration factor does not increase due to intermittent operation, etc., the calcium ion concentration in the cooling water does not increase, and the precipitation film The formation of is insufficient. When the equipment is operated under such circumstances, it is greatly affected by oxidizing substances such as oxidizing disinfectant typified by sodium hypochlorite added as a disinfecting component to dissolved oxygen and water in water. There is a problem that the corrosion proceeds remarkably.

  In addition, a cooling water system failure inhibitor comprising an isothiazolone compound as a slime inhibitor, and a mixture containing an anticorrosive and a scale inhibitor has been proposed as a multifunctional water treatment agent (see Patent Document 3). .

Japanese Patent Publication No. 1-60553 Japanese Patent Publication No.58-4682 JP 2002-193711 A

  An object of the present invention is to provide a multifunctional water treatment agent that can solve the above-described problems in the prior art and can exhibit a stable effect.

As a result of intensive research on the multifunctional water treatment agent composition that satisfies the above-mentioned purpose, the present inventors have formulated a hydrazide compound as a slime control agent, thereby reducing the cooling water concentration level and the cooling water flow rate slow. Regardless of the fact that stable slime control performance can be obtained, and more surprisingly, the anti-corrosion performance has been greatly improved, and the multifunctional water treatment composition has low toxicity to the human body and the environment and high safety in handling. The present invention has been reached.
That is, the present invention relates to a multifunctional water treatment agent characterized by containing a hydrazide compound, a carboxylic acid-based low molecular weight polymer, and an azole compound as active ingredients.

  The multifunctional water treatment agent of the present invention is a cooling water system in which the concentration of the cooling water is lowered and the concentration of the metal material in the low flow rate region is reduced and the concentration is advanced as in the conventional multifunctional water treatment agent. In addition to solving the problem of not being able to exhibit a stable slime-inhibiting effect, a significant improvement in the anticorrosive effect has been recognized in terms of anticorrosion performance. In addition, the concern about adverse effects on the human body and the environment at the time of preparation and strong skin irritation are reduced, and the industrial utility value is extremely high.

Schematic of a corrosion test apparatus. Change in redox potential over time.

  Examples of the hydrazide compound in the present invention include carbohydrazide, maleic acid hydrazide, maleic acid hydrazide polymer, acrylic acid hydrazide polymer, adipic acid hydrazide, isophthalic acid hydrazide, and succinic acid hydrazide. It is preferable to use carbohydrazide, which is cheaper than conventional slime inhibitors and is harmless with nitrogen and carbon dioxide. Although the present invention can provide sufficient slime-suppressing performance with carbohydrazide alone, it can be used in combination with commonly known slime-inhibiting agents such as 2-bromo-2-nitropropane-1,3-diol. Good.

  Examples of the carboxylic acid-based low molecular weight polymer used in the present invention include copolymers of acrylic acid and other monomers such as poly (meth) acrylic acid soda, (meth) acrylic acid-acrylamide copolymer, and polyanhydride maleic. Examples thereof include acid, maleic anhydride such as maleic anhydride-isobutylene copolymer and other copolymers, and acrylic acid-maleic anhydride copolymer.

  Further, a carboxylic acid-based polymer containing phosphinic acid or a sodium salt thereof represented by the following general formula (1), bis (poly-2-carboxyethyl) phosphinic acid or a sodium salt thereof, and the following general formula (2) Phosphinocarboxylic acid copolymers as indicated can also be used.

（式中ＭはＨまたはＮａ）

(Wherein M is H or Na)

（式中、Ｍは水素原子又はアルカリ金属原子、Ｘ、Ｙは夫々次式）

(In the formula, M is a hydrogen atom or an alkali metal atom, and X and Y are respectively the following formulas)

又は

Or

（式中、Ｍ’はＭと同意義でn＋m＋n’＋m’＝１６である。但しn＋m＝０であってもよい。）で示される基を示す。

(In the formula, M ′ has the same meaning as M, and n + m + n ′ + m ′ = 16, where n + m = 0 may be used).

  As these carboxylic acid-based low molecular weight polymers, those having a molecular weight in the range of 500 to 50,000 are generally used. The carboxylic acid-based low molecular weight polymer particularly preferred as the admixture is acrylic acid, 2-acryloylamino-2-methyl-1-propanesulfonic acid sodium, sodium hypophosphite addition polymer, and / or polymaleic anhydride. They can be obtained as 50% aqueous solution under the trade names Berglene 400 (manufactured by FMC) and Berglen 200LA (manufactured by FMC), respectively.

  Examples of the azole compound used in the present invention include benzotriazole, tolyltriazole, 5-n-propylbenzotriazole, and 5-hydroxybenzotriazole. It is preferable to use it. In order to obtain the mixed agent of the present invention, each compound can be blended in a desired ratio, and can be easily prepared by adjusting the pH as necessary or appropriately diluting with water.

  The admixture according to the present invention is usually obtained in a liquid state, and the compounding amount of the compound to be compounded is basically within the range conventionally used for each purpose, but the preferable compounding ratio is hydrazide compound 5 -30 wt%, carboxylic acid-based low molecular weight polymer 5-20 wt%, azole compound 0.5-5 wt%.

  The multifunctional water treatment agent of the present invention can be preferably used for circulating cooling water in which slime failure, corrosion failure, and scale failure occur. In the present invention, in the treatment of the circulating cooling water using the multifunctional water treatment agent, the oxidation-reduction potential of the circulating cooling water is kept in the range of −200 to +100 mV, so that slime suppression, corrosion prevention and scale prevention effects are achieved. It can be obtained stably. The oxidation-reduction potential (sometimes referred to as ORP) can be measured by, for example, collecting circulating cooling water from a storage pit and using an oxidation-reduction potentiometer (HORIBA D-23 type) or the like.

  The amount of the multifunctional water treatment agent of the present invention added to the circulating cooling water is appropriately determined depending on the blending ratio of each compound and the cooling water quality, but the redox potential of the circulating cooling water is in the range of −200 to +100 mV. In addition, it is desirable to add an amount that can be kept preferably for one week or more. Usually, it is desirable to add such that the concentration of the multifunctional water treatment agent in the circulating cooling water is 100 to 1200 mg / L, more preferably 100 to 800 mg / L, and most preferably 100 to 500 mg / L. In addition, a multifunctional water treatment agent can be added to the makeup water to adjust the amount of the water treatment agent in the circulating cooling water. When the multifunctional water treatment agent concentration is below the above concentration, the anticorrosive effect and slime suppression performance are insufficient, and when it exceeds the above concentration, copper ions in the circulating cooling water are reduced and scaled, The system may become anaerobic and harmful effects such as generation of bad odors such as hydrogen sulfide may occur. Moreover, it is economically unpreferable to add more than the desirable upper limit concentration.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

In Examples 1 to 3 and Comparative Examples 1 to 5, each agent of the present invention blended with liquid carbohydrazide and a comparative sample were prepared, and the test piece ( The anticorrosive effect for materials (iron, copper) was determined. Table 1 shows the test results. FIG. 2 shows changes with time of the oxidation-reduction potential in Example 1 and Comparative Examples 1 to 5.
<Corrosion rate of steel>
A disk-shaped test piece (SPCC, surface area 38 dm ² ) was attached to a test piece fixing jig, and the corrosion rate (mdd = mg / dm ² / day) was determined from the corrosion weight loss before and after the test. The test piece weight after the test was the weight after the test piece after the test was washed with 15% hydrochloric acid containing a rust preventive.
<Corrosion rate of copper material>
A disk-shaped test piece (C1100P, surface area 38 dm ² ) was attached to the test piece fixing jig, and the corrosion rate (mdd = mg / dm ² / day) was determined from the corrosion weight loss before and after the test. The test piece weight after the test was the weight after the test piece after the test was washed with 15% hydrochloric acid containing a rust preventive.
<Redox potential of test water>
During the test period, the redox potential of the test water was determined by measuring with an ORP meter (HORIBA D-23 type).
<Test conditions>
(Test water quality)
Test water: Kanamachi district water, Tokyo pH: 7.0-7.5
Electrical conductivity: 25-35 mS / m
Acid consumption (pH 4.8): 30 to 40 mg CaCO ₃ / L
Total hardness: 80-90mg / L
Cl ⁻ : 25 to 35 mg / L
SO ₄ ²⁻ : 30 to 40 mg / L
SiO _2: 20~30mg / L
(Test equipment conditions)
Test temperature: 40 ° C
Test period: 7 days Test piece rotation speed: 200 rpm
Aeration volume: 400 ml / min

Examples 1-3
The present invention agents 1 to 3 shown below were respectively prepared, and the anticorrosive effect when 400 mg / L was added to the test water was confirmed with a corrosion test apparatus. The test results are shown in Table 1.

Invention agent 1
Carbohydrazide 15 parts by weight Berglene 200LA (molecular weight 900) 20 parts by weight Benzotriazole 2 parts by weight Water 63 parts by weight Total 100 parts by weight

Invention agent 2
Carbohydrazide 15 parts by weight Berglene 400 (molecular weight 1700) 20 parts by weight Benzotriazole 2 parts by weight Water 63 parts by weight Total 100 parts by weight

Invention agent 3
Carbohydrazide 15 parts by weight Berglene 400 (molecular weight 1700) 20 parts by weight Trityltriazole 2 parts by weight Water 63 parts by weight Total 100 parts by weight

Comparative Example 1
In order to grasp the degree of corrosion of the test water, a blank test was performed without adding a chemical. The test results are shown in Table 1.

Comparative Example 2
In order to grasp the behavior of carbohydrazide itself with respect to the metal material, a test was conducted in which carbohydrazide was added at 60 mg / L to the test water. The test results are shown in Table 1.

Comparative Example 3
In order to grasp the behavior of the carboxylic acid polymer and the azole itself with respect to the metal material, the following comparative sample 1 was prepared, and the anticorrosion effect when 400 mg / L was added to the test water was confirmed with a corrosion test apparatus. The test results are shown in Table 1.

Comparative sample 1
Berglen 200LA (Molecular weight 900) 20 parts by weight Benzotriazole 2 parts by weight Water 78 parts by weight Total 100 parts by weight

Comparative Example 4
In order to grasp the behavior of the hydrazine-based multifunctional water treatment agent with respect to the metal material, the following comparative sample 2 was prepared, and the anticorrosion effect when 400 mg / L was added to the test water was confirmed with a corrosion test apparatus. The test results are shown in Table 1.

Comparative sample 2
Hydrated hydrazine 29 parts by weight Berglene 200LA (molecular weight 900) 20 parts by weight Benzotriazole 2 parts by weight Water 49 parts by weight Total 100 parts by weight

Comparative Example 5
In order to understand the behavior of the CMT metal salt complex-based water treatment agent with respect to the metal material, 5-chloro-2-methylisothiazolin-3-one magnesium (II) chloride (hereinafter referred to as CMT) which is a general CMT metal salt complex · MgCl ₂₎ was prepared following comparative sample 3 was formulated as a slime-controlling agent, to confirm the anti-corrosion effect of adding 400 mg / L in the test water at corrosion test apparatus. The test results are shown in Table 1.

Comparative sample 3
CMT · MgCl ₂ 10% solution 10 parts by weight 2-bromo-2-nitropropane-1,3-diol 5 parts by weight Berclene 200LA (molecular weight 900) 20 parts by weight benzotriazole 2 parts by weight Diethylene glycol 8 parts by weight Water 55 parts by weight Total 100 parts by weight

Example 4
With respect to the inventive agent 1, the following tests (1) to (4) were conducted using an open-type circulating cooling water system model plant as a test apparatus.
(1) The corrosion rate (immersion for 30 days) of a test piece (material: iron, copper) installed in the cooling tower lower water tank and piping was measured.
(2) A piece of wood (size 100 mm × 200 mm, hereinafter referred to as slime board) was immersed in the cooling tower lower water tank, and the adhesion capacity of slime to the slime board (every 14 days) was measured.
(3) The concentration in the slime inhibitor system of the circulating cooling water collected from the water storage pit (every 3 days) was measured. Examples 4 to 6 and Comparative Examples 7 and 9 were analyzed by redox titration with sodium thiosulfate, and Comparative Example 10 was analyzed by liquid chromatography.
(4) The oxidation-reduction potential of the circulating cooling water was measured every 3 days.

The model plant had a water volume of 1 m ³ and a circulating water volume of 4 m ³ / hr. A heat exchanger (manufactured by SUS304, heat transfer area 0.707 m ² ) was provided in the system, and the outlet temperature was adjusted to 50 ° C. 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 30 ° C. Industrial water was used as make-up water for the model plant, and a reagent agent equivalent to 50 mg / L of the make-up water amount was injected twice a day. In addition, a reagent supply equivalent to 200 mg / L with respect to the amount of retained water was added as a basic charging process at the start of the test.
The test was continued for 30 days. At this time, the concentration factor of the cooling water was controlled based on the electric conductivity, and the set value was set to 7 times. The test results are shown in Tables 2 and 3.

Examples 5-6
The test was conducted in the same manner as in Example 4 except that the reagent agents were changed to the present invention agents 2 and 3, respectively. The test results are shown in Tables 2 and 3.

Comparative Example 6
The test was conducted in the same manner as in Example 4 with no reagent provided. The test results are shown in Tables 2 and 3.

Comparative Example 7
The test was conducted in the same manner as in Example 4 except that carbohydrazide was used as the reagent, 7.5 mg / L of the reagent was added to the makeup water, and the basic input concentration with respect to the retained water was 30 mg / L. . The test results are shown in Tables 2 and 3.

Comparative Example 8
A test was performed in the same manner as in Example 4 except that the reagent was changed to Comparative Sample 1. The test results are shown in Tables 2 and 3.

Comparative Example 9
A test was performed in the same manner as in Example 4 except that the reagent was changed to Comparative Sample 2. The test results are shown in Tables 2 and 3.

Comparative Example 10
A test was performed in the same manner as in Example 4 except that the reagent was changed to Comparative Sample 3. The test results are shown in Tables 2 and 3.

1 2L beaker 2 Test piece fixing shaft (SUS)
3 belt (rotary motor connection)
4 Ball filter for aeration 5 Disc type test piece (copper)
6 Disc type test piece (iron)
7 Test water

Claims (5)

  A multifunctional water treatment agent comprising a hydrazide compound, a carboxylic acid-based low molecular weight polymer, and an azole compound as active ingredients.   The multifunctional water treatment agent according to claim 1, wherein the hydrazide compound is carbohydrazide.   The carboxylic acid-based low molecular weight polymer is acrylic acid, sodium 2-acryloylamino-2-methyl-1-propanesulfonate, sodium hypophosphite addition polymer, and / or polymaleic anhydride. The multifunctional water treatment agent described.   The multifunctional water treatment agent according to any one of claims 1 to 3, wherein the azole compound is benzotriazole or tolyltriazole. It is a processing method for slime suppression, corrosion prevention, and scale prevention in a circulating cooling water system, wherein the oxidation-reduction potential of the circulating cooling water is maintained in a range of -200 to +100 mV. A method for treating circulating cooling water, comprising adding the multifunctional water treatment agent according to one item to circulating cooling water.

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