JPH0640996B2 - Cooling water treatment agent and cooling water treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is intended to prevent various obstacles caused by water, such as slime trouble, scale trouble and corrosion trouble, which occur in a circulating cooling water system of a refrigerating apparatus. It relates to a cooling water treatment agent to be used.

[Conventional technology]

Cooling water for refrigerating machines and the like is often circulated and reused through a cooling tower to save water.

Since some of the cooling water evaporates when it is cooled by releasing latent heat in the cooling tower, the cooling water gradually concentrates, and various impurities in the water, such as calcium ions, bicarbonate ions, and chlorides. Ions, silica, suspended substances, organic substances, etc. are concentrated, causing various obstacles.

The main obstacles are scale obstacles, which is the precipitation of insoluble inorganic salts such as calcium carbonate and silica, and corrosion of copper and iron pipes, which are the heat exchange material of refrigeration equipment. Furthermore, due to the growth of bacteria and algae, a sticky mud substance in the heat exchange part adheres to reduce the heat exchange efficiency, or the packing material of the cooling tower is blocked to reduce the cooling efficiency. The slime obstacles that make up are also a big problem.

In order to prevent such troubles occurring in the circulating cooling water system, various water treatment agents are commercially available, but they are generally mixed with a scale inhibitor, a corrosion inhibitor, a slime inhibitor, etc. It was done. Of these various chemical components, most of them employ polymaleic acid or phosphonic acid as a scale preventing component and azoles as an anticorrosive, and various compounds are used as a slime inhibitor. However, hydrazine, isothiazolones, and organic bromines are common.

However, each of these slime inhibitors has the following drawbacks. That is, hydrazine has a high algicidal effect and is inexpensive, but its bactericidal power is weak, and it cannot exhibit a sufficient effect for erasing Legionella bacteria which has been a problem in recent years. On the other hand, isothiazolone-based drugs are extremely irritating to the skin and are inconvenient to handle.

In addition, organic bromine-based compounds are extremely expensive and weak in algicidal activity.

As described above, the currently used medicines have various drawbacks as described above, particularly regarding slime prevention, and they are not always satisfactory.

[Problems to be Solved by the Invention]

In recent years, due to tight water supply and rising water prices, the circulating cooling water system of refrigeration systems has been forced to operate at high concentration to save water, and along with this, there are frequent failures of slime, scale, and corrosion. ing.

For this reason, in highly concentrated cooling water systems, with regard to agents added to prevent damage caused by water, products that have sufficient sterilization, algaecidal effects, scale prevention, anticorrosion effects, and are easy to handle and inexpensive Was desired.

Therefore, the present invention is to provide a water treatment chemical for circulating cooling water that can meet such a demand, and particularly a cooling water treatment chemical excellent in slime prevention effect and a cooling water treatment using the same. It is intended to provide a method.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present inventors are satisfied with all conventional slime preventives in terms of algicidal effect, bactericidal effect, safety in handling, and further, compatibility with scale inhibitors and anticorrosive agents. In view of what was not possible, as a result of extensive and extensive investigations on various compounds, it was discovered that some diphenylmethane compounds have an excellent algicidal effect, and the present invention has been completed.

That is, the present invention relates to 2,2'-dihydroxy-5,
A cooling water treatment agent containing 5'-dichlorodiphenylmethane, and 1 to 100 of 2,2'-dihydroxy-5,5'-dichlorodiphenylmethane in circulating cooling water.
This is a cooling water treatment method in which it is present at a concentration of mg /.

2,2'-dihydroxy-5,5 'used in the present invention
-Dichlorodiphenylmethane has been conventionally used as a preservative for paints, but no algicidal activity was observed. However, according to the new findings of the present inventors, 1 to 100 mg /, preferably 5 to 2 in cooling water.
2,2'-dihydroxy-5,5'-at a concentration of 5 mg /
It was found that the presence of dichlorodiphenylmethane can effectively kill green algae and cyanobacteria, and at the same time, shows an excellent bactericidal effect against various bacteria including Legionella spp.

Furthermore, the advantages of 2,2'-dihydroxy-5,5'-dichlorodiphenylmethane are low toxicity and extremely low skin irritation. This is not only advantageous for equipment managers who handle water treatment chemicals, but also has the advantage of having less influence such as pollution on the environment around the equipment.

However, the 2,2′-dihydroxy-5,5′-dichlorodiphenylmethane having such advantages is a one-pack type cooling water treatment solution which is dissolved in a solvent such as water together with a scale inhibitor and an anticorrosive agent, if necessary. When it was used as a drug, if it was left open to the air, a precipitate was formed after about one month, and the stability as a product was difficult.

The present inventors have also conducted research on this point, and as a result, by adding glycols or amines, 2,2 '
It has been found that cooling water treatment agents containing -dihydroxy-5,5'-dichlorodiphenylmethane are effectively stabilized. That is, 2,2'-dihydroxy-5,5 '
-Stabilizers for dichlorodiphenylmethane are glycols such as ethylene glycol, amines such as mono-, di-, or trimethylamine, mono-, di-, or triethylamine, 3-aminopropyl methyl ether, etc. Included in 2,
By adding 20 to 500 parts by weight of a stabilizer to 100 parts by weight of 2'-dihydroxy-5,5'-dichlorodiphenylmethane, it is possible to obtain a cooling water treatment agent which does not cause precipitation over a long period of time. became.

[Action]

The main action of the cooling water treatment agent according to the present invention is 2,2 ′.
-The effect of algicidal and bactericidal effects by dihydroxy-5,5'-dichlorodiphenylmethane and the effect of preventing the precipitation of the drug by glycols or amines.

Moreover, this drug has no irritation to the skin even in a concentrated solution, is easy to handle, and has excellent product stability.

Example 1 composition _{Ca (NO 3) 2: 1.0g} , KCl: 0.25g, KH 2 PO 4: 0.25g, MgSO
_{4 · 7H 2 O: 0.25g,} FeCl 3: 0.002g, water: consisting of 1 Detoma - to what dilution (Detmer) medium to 1/2, the dry weight of per medium 1m Chlorella Sp preincubated. Suspended to 0.2 mg. The above suspension was dispensed into L-shaped test tubes in 15 m increments, and 2,2'-dihydroxy-5,5'-dichlorodiphenylmethane (HCPM) was added to 2.5, 5.0 and 1 respectively.
After adding so that the amount would be 0.0 mg /, shaking culture was carried out at 30 ° C. and 30 rpm for 7 days while irradiating with 10,000 Lux of light, and the algicidal effect was evaluated.

As a result, in the case of HCPM 5.0 and 10.0 mg /, it was found that the attenuation was complete, and it was found that HCPM has a sufficient algicidal effect.

[Comparative Example 1] Under the same conditions as in Example 1, without addition of a chemical, 5-chloro-2-
Methyl-4-isothiazolin-3-one (CMI) 0.5, 1.0, 2.0 mg /, 2-bromo-2-nitropropane-1,3-diol (BNPD) 10.
The algicidal activity against Chlorella Sp. Was evaluated and compared for the cases of adding 0 and 20.0 mg / each.

The results of Example 1 and Comparative Example 1 were as summarized in Table 1.

According to this, the algicidal effect of HCPM relating to the present invention is remarkable as compared with other drugs.

Example 2 Phosphate buffer solution containing KH ₂ PO ₄ and Na ₂ HPO ₄ (concentration 1 /
15M, pH7.0) 10m was dispensed into a test tube, and after sterilization, the number of pre-cultured Legionella pneumophila was 1
It was added so as to be 10 ⁴ per m.

5,2,2'-dihydroxy-5,5'-dichlorodiphenylmethane (HCPM) was added to the above-mentioned bacterial solution 5, 10, respectively.
Add 20.0mg / to add 3 in a constant temperature bath at 30 ℃.
The cells were shaken at 0 rpm, and the viable cell count was measured after 1, 3, 6, and 24 hours, respectively. The results are shown in Table 2.

[Comparative Example 2] Hydrazine as a drug was added to the same bacterial solution as in Example 2 at a concentration of 20, 40 mg / each, and the raw material after 1, 3, 6, 24 hours under the same conditions as in Example 2 was added. The number of bacteria was measured. The results are shown in Table 2 together with the results of Example 2.

From this, it is clear that the bactericidal effect of the HCPM of the present invention is excellent.

Example 3 A cooling water treatment chemical having the composition shown below was prepared to obtain a brown transparent liquid. When the above liquid was left at room temperature in an open state, a precipitate was generated on the 25th day.

2,2'-Dihydroxy-5,5'-dichlorodiphenylmethane 5% by weight Sodium polymaleate 10% by weight Benzotriazole 1.5% by weight Potassium hydroxide 5% by weight Water 78.5% by weight On the other hand, ethylene glycol 5% by weight was added to this composition. When the same test was performed on the above-mentioned product, the number of days until the generation of precipitates could be extended to 50 days.

Further, the same test was conducted on the composition to which 5% by weight of 3-aminopropyl methyl ether was added, and no precipitate was observed even after 4 months.

From this, it is clear that the drug to which the stabilizer of the present invention is added exhibits a long-term stabilizing effect.

[Example 4] The agents of Example 3 were evaluated for scale prevention effect.

Electrical conductivity 2000 μS / cm, total hardness 500 mg / as
CaCO ₃ , calcium hardness 400 mg / as CaCO ₃ , M-
Cooling water under the water quality condition of alkalinity 400 mg / as CaCO ₃ was circulated at 40 ° C. for 18 hours, and the amount of scale deposited and deposited on the electric heater was measured. The scale deposition amount without chemicals was 560 mg. 200 mg /
When added, the amount deposited was 5 mg or less.

[Example 5] With respect to the corrosion preventing effect on copper of the chemical agent of Example 3, the corrosion degree (mdd) of the corrosion test piece immersed in Tokyo water at 60 ° C for 7 days was 1.17 mdd when the chemical was not added. The drug was 200 mg / 0.48 mdd when added.

As a result of Examples 4 and 5 described above, it was demonstrated that the agent of the present invention was remarkably excellent in the scale-inhibiting effect and the corrosion-inhibiting effect.

〔The invention's effect〕

The cooling water treatment agent of the present invention can effectively prevent and prevent disorders caused by highly concentrated utilization of circulating water, particularly slime disorders and propagation of pathogenic bacteria. Compared with the other features, it has fewer defects and is safe and easy to handle.

Claims (4)

[Claims] 1. A cooling water treatment agent comprising 2,2'-dihydroxy-5,5'-dichlorodiphenylmethane. 2. A cooling water containing 20 to 500 parts by weight of a stabilizer selected from glycols and amines with respect to 100 parts by weight of 2,2'-dihydroxy-5,5'-dichlorodiphenylmethane. Processing chemicals. 3. The cooling water treatment chemical according to claim 1, which contains at least one of a scale inhibiting component and a corrosion inhibiting component. 4. 2,2'-dihydroxy-in the circulating cooling water
5,5'-dichlorodiphenylmethane 1-100 mg /
The method for treating cooling water is characterized in that it is present at a concentration of.