KR100470107B1 - Composition for corrosion inhibitors for a closed loop heating system - Google Patents

Abstract

The present invention relates to a plant protection agent composition for a hermetic heating system, comprising (a) nitrite salt, (b) molybdate salt, (c) acrylate polymer, (d) azole salt and (e) water. When applied to the hermetic heating system to protect the composition of the hermetic heating system to protect the components of the hermetic heating system better than the conventional phosphate-based cleaning agent to prevent the extended heating life of the hermetic heating system and to reduce the thermal efficiency.

Description

Composition protective agent composition for closed heating system {Composition for corrosion inhibitors for a closed loop heating system}

[TECHNICAL FIELD OF THE INVENTION]

The present invention relates to a facility protection agent composition for a hermetic heating system, and more particularly, to protect the entire heating equipment because it is excellent in anti-corrosion effect on carbon steel, aluminum alloy and copper alloy, etc., without being precipitated or scaled in general heating water. (A) nitrite salt, (b) molybdate salt, (c) acrylate polymer, (d) azole salt, and (e) water. will be.

[Private Technology]

In the conventional hermetic heating system, phosphate-based cleansing agents are mainly used. The anti-rusting mechanisms of these cleansing agents mainly combine cations and phosphates such as calcium and magnesium in water to form thin scales and form these scale coatings on the entire pipe. It is designed to plan. In addition, these thin scale coatings maintain the coating over and over again, with the process of breaking and regenerating continuously. To maintain the coating well, there must be adequate water quality of adequate hardness and sufficient phosphate to fit it.

However, the sealed heating device is difficult to control the heating water quality in reality, and since it is often used with tap water having a low hardness component, it is difficult to obtain a sufficient rust prevention effect, and the metal material of the entire sealed heating device is aluminum, in addition to carbon steel. Because it is made of various kinds of metals such as copper, rust preventive effect could not be obtained by phosphate-based cleansing agent alone.

In order to compensate for this, US Pat. Nos. 4,828,452 and 4,961,878 have proposed a dedicated anticorrosive composition. In these patents, nitrite salts or nitrates are used to suppress corrosion of carbon steel, molybdate salts are used for aluminum, and azoles are used for copper pipe. The anticorrosive agents are not an precipitated anticorrosive agent like a conventional phosphate type, but an oxide anticorrosive agent which allows the metal to form a passivation film by itself. The anodized anticorrosive may form an anticorrosive coating in a much smaller amount than the precipitated coating and is also irrelevant to water quality. However, the compositions also have problems such as molybdate salts, such as molybdate salts combined with calcium or magnesium as a hard water component to form a scale on the aluminum surface to reduce the efficiency of the aluminum radiator when used for a long time.

The present invention was developed to solve the problems of the prior art as described above, and an object of the present invention is to operate a hermetic heating system having various metals together, and to configure the system in a relatively small amount without any influence on the hardness component. It aims at providing the protective composition for heating installations which prevents the corrosion of a metal and can be used for a long time.

In order to achieve the above object, the present invention comprises (a) a nitrite salt, (b) molybdate salt, (c) acrylate polymer, (d) azole salt and (e) water. It provides a facility protective agent composition for.

In another aspect, the present invention comprises (a) nitrite salt, (b) molybdate salt, (c) acrylate polymer represented by the following formula (1), (d) azole salt and (e) water Provided is a facility protective composition for a system.

[Formula 1]

In Formula 1, n is 10000 to 20000, and R is a compound represented by Formula 2 below.

[Formula 2]

In Formula 2, R ₁ and R ₂ may be the same or different from each other, and hydrogen or carbon is a straight chain alkyl group having 1 to 5 carbon atoms.

Hereinafter, the present invention will be described in detail.

The present invention includes a nitrite salt, molybdate salt, acrylate polymer, azole salt and water so as to form a constant concentration in general tap water or ground water as a hermetically sealed heating system protective agent composition to form a passivation film without scale formation. .

In the present invention, the nitrite salt is used to prevent corrosion of cast iron and carbon steel. The amount of the nitrite salt is preferably 5 to 10% by weight, more preferably 6 to 8% by weight in the total hermetic heating system equipment protective agent composition. If the amount of the nitrite salt is less than 5% by weight has a bad effect on the metal of the Fe-based, if it exceeds 10% by weight of the nitrite salt is poor solubility and causes a bad effect on the metal system. Preferably, the nitrite salt is sodium nitrite, potassium nitrite or a mixture thereof.

The present invention also uses molybdate salts to prevent corrosion of aluminum. The amount of molybdate salt used in the present invention is preferably 5 to 10% by weight, more preferably 6 to 8% by weight in the total hermetic heating system equipment protector composition. If the amount of the molybdate salt is less than 5% by weight can cause corrosion because the aluminum can not be achieved, if it exceeds 10% by weight solubility problem occurs and precipitation occurs immediately. Preferably, the molybdate salt is one or a mixture of two or more selected from the group consisting of ammonium molybdate, ammonium phospho molybdate, sodium molybdate and potassium molybdate.

When used together, the nitrite salt and molybdate salt show an anti-corrosion synergistic effect to protect the carbon steel and aluminum alloy at the same time. However, when the molybdate salt is used for a long time, there is a problem in that it combines with calcium ions or magnesium ions in water to form a white insoluble compound, forms a scale, prevents heat transfer, and lowers the efficiency of the heat exchanger. . The present invention includes an acrylate polymer to solve the above problem.

The acrylate polymer used in the present invention is preferably an acrylate of the formula (1). The acrylate polymer inhibits the interaction between molybdate salts and calcium or magnesium ions so that precipitation or scaling does not occur even after long use. In the present invention, the amount of the atryl polymer is preferably 0.1 to 1% by weight, more preferably 0.5 to 1% by weight in the total hermetic heating system equipment protecting agent composition. If the amount of the acrylate polymer is less than 0.1% by weight can not prevent the condensation and precipitation phenomenon of the molybdate salt, if it exceeds 1.0% by weight rather it induces the condensation of the composition to cause precipitation.

The present invention also includes an azole salt to prevent corrosion of the copper tube. The amount of the azole salt used in the present invention is preferably 1 to 5% by weight, more preferably 3 to 5% by weight in the total hermetic heating system equipment protective agent composition. If the amount of the azole salt is less than 1% by weight, an anticorrosive coating may be incompletely formed on the copper surface, and partial corrosion may occur. Preferably the azole salt in the present invention is one or two or more mixtures selected from the group consisting of sodium tolyltriazole, benzotriazole, potassium tolyltriazole, sodium mercaptobenzothiazole and mixtures thereof.

The present invention also includes water. The water serves as a solvent for dissolving the above-mentioned components, preferably the water is distilled water. In the present invention, the amount of water used is suitable for dissolving the above-mentioned components, and may be determined in consideration of circumstances such as storage or transportation. Preferably the amount of water is 74 to 88.9% by weight.

Moreover, it is preferable that pH of the installation protective agent composition for hermetic heating systems of this invention is 9-11. The composition of the present invention within the pH range shows a more excellent equipment protection effect. In another aspect, the present invention may further include a pH adjusting buffer to maintain the pH.

The equipment protection agent composition for a hermetic heating system of the present invention is added to the circulating water of the hermetic heating system, and the amount of the protective agent used is preferably controlled so that the concentration of the composition is 1000 to 50000 ppm.

Hereinafter, examples of the present invention will be described. However, the following examples are intended to illustrate the invention and the present invention is not limited to the following examples.

Example 1

6.0 wt% sodium nitrite, 8.0 wt% sodium molybdate, 1.0 wt% acrylate polymer and 3.0 wt% sodium tolyltriazole were dissolved in distilled water to prepare a 100 wt% equipment protective composition for a closed heating system. In the acrylate polymer used in the present Example, a compound in which n is 11000 and R ₁ and R ₂ are CH ₃ in Chemical Formula 1 was used. The pH of the composition was 10.2.

[Examples 2 to 3]

Except that the amount of the components used in Example 1 was changed as shown in Table 1 was prepared in the same manner as in Example 1 facility protective agent composition for a closed heating system.

Comparative Example 1

Except not using an acrylate polymer, a facility protective agent composition for a closed heating system was prepared in the same manner as in Example 1.

[Comparative Examples 2 to 3]

Instead of using an acrylate polymer, Comparative Example 2 uses 2-phosphono-1,2,4-butanetricarboxylic acid (PBTC), and Comparative Example 3 uses HEDP (1-hydroxyethylidene-1,1-diphosphonic acid). Except that was prepared in the same manner as in Example 1 facility protective agent composition for a closed heating system.

[Experiment 1] Corrosion Test

It was tested according to the metal corrosion test method of KS M 2142 using the equipment protective agent composition for hermetic heating system of Examples 1 to 3 and Comparative Examples 1 to 3. However, the metal specimens were aluminum, steel, copper, and each specimen was separated by a synthetic resin space. 750 ml of 750 ml of artificial corrosion synthetic water prepared by dissolving the test pieces up to 0.1 mg unit and dissolving 148 mg of sodium sulfate, 165 mg of sodium chloride, and 138 mg of sodium bicarbonate in 1 L of distilled water was prepared. After adding the composition corresponding to the test solution and without artificial air injection at 88 ° C., the mass change of the test piece was measured to 0.1 mg unit after 336 hours, and the corrosion loss per unit area was expressed in mg / cm ² unit.

The results of the test are shown in Table 1 below.

Experiment 2 Precipitation Test

After completion of the anticorrosive test of Experiment 1, the test solution used was uniformly mixed, and then, 100 ml was taken, and the precipitates were separated by rotating at 2000 rpm for 10 minutes in a centrifuge. At this time, the volume of the separated precipitate was expressed in ml / 100ml units. The results of the test are shown in Table 1 below.

TABLE 1

Furtherance Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Acrylate polymer (% by weight) 1.0 0.5 1.0 - PBTC HEDP Sodium Nitrite (wt%) 6.0 6.0 6.0 6.0 6.0 6.0 Sodium molybdate (% by weight) 8.0 8.0 8.0 8.0 8.0 8.0 Triazole soda (% by weight) 3.0 3.0 3.0 3.0 3.0 3.0 water Add up to 100% by weight Anticorrosive (corrosion loss) (mg / cm ² ) aluminum 0.05 0.04 0.05 0.10 0.10 0.12 River 0.01 0.01 0.01 0.05 0.02 0.02 copper 0.01 0.01 0.01 0.01 0.02 0.02 Precipitation (ml / 100ml) 0 0 0 0.05 0.04 0.05

As shown in Table 1, Examples 1 to 3 using the equipment protection agent composition for a hermetic heating system of the present invention is superior in corrosion resistance to all kinds of metals tested in aluminum, steel and copper as compared to Comparative Examples 1 to 3. No precipitate was detected in the precipitation test.

As described above, when the present invention is applied to the hermetic heating composition for the hermetic heating system to the hermetic heating system to prevent corrosion of the metal constituting the system in a relatively small amount without affecting the type and hardness components of the metal and use for a long time Can be.

Claims (8)

(a) nitrite salts; (b) molybdate salts; (c) an acrylate polymer; (d) azole salts; And (e) water Facility protective agent composition for a closed heating system comprising a. The method of claim 1, wherein the acrylate polymer is a protective equipment composition for a closed heating system, characterized in that the acrylate polymer represented by the following formula (1): [Formula 1] In Formula 1 n is 10000 to 20000, R is a compound represented by the formula (2), [Formula 2] In Formula 2, R ₁ and R ₂ may be the same or different from each other, and hydrogen or carbon is a straight chain alkyl group having 1 to 5 carbon atoms. According to claim 1 or 2, wherein the equipment protection agent composition for a closed heating system is 5 to 10% by weight of the nitrite salt, 5 to 10% by weight of the molybdate salt, 0.1 to 1.0 weight of the acrylate polymer %, 1 to 5% by weight of the azole salt and 74 to 88.9% by weight of water. The facility protection agent composition for a hermetic heating system according to claim 1 or 2, wherein the facility protection agent composition for a hermetic heating system has a pH of 9 to 11. The method of claim 4, wherein the system protection composition for a hermetic heating system further comprises a pH control buffer composition for a hermetic heating system. The method of claim 1 or 2, wherein the nitrite salt is sodium nitrite, potassium nitrite or a mixture thereof, the protective equipment composition for a closed heating system. 3. The molybdate salt according to claim 1 or 2, wherein the molybdate salt is one or two or more mixtures selected from the group consisting of ammonium molybdate, ammonium phospho molybdate, sodium molybdate and potassium molybdate A facility protective agent composition for a hermetic heating system. The method according to claim 1 or 2, wherein the azole salt is one or two or more mixtures selected from the group consisting of sodium tolyltriazole, benzotriazole, potassium tolyltriazole, sodium mercaptobenzothiazole and mixtures thereof. Facility protective agent composition for hermetic heating system characterized by the above-mentioned.