KR20060122166A - Treatment method for prevent scale formation of cooling water system - Google Patents

Abstract

A water treatment method for inhibiting the formation of scale in a cooling water system is provided to offer a superior scale suppression effect though a small quantity of jetting concentration. A water treatment compound consists of organic phosphate compound of 0.1-40 weight %, acrylate co-polymer of 0.1-30 weight % and water of 30-99.8 weight %. The organic phosphate compound is the mixture including two selected from hydroxy ethylidine diphosphonic acid, hydroxy phosphono carboxyl acid, amino trimethylene phosphonic acid, phosphono butane tri carboxyl acid and ethylene diamine tetra methylidine phosphonic acid. Preferably, in the water treatment compound, the organic phosphate compound of 1.0-35 weight % is used.

Description

{Treatment method for prevent scale formation of cooling water system}

The present invention relates to a scale formation inhibiting water treatment method for a cooling system, and more particularly, a composition comprising an organic phosphate compound and an acrylate copolymer. The present invention relates to a scale formation inhibiting water treatment method for a cooling system that can effectively suppress scale formation of a cooling system having a high calcium hardness at a concentration of 10 ppm or less.

Major industrial facilities at the national base, such as petrochemicals, refineries, textiles, steel, electronics, and power plants, use cooling systems to cool the heat generated during the process.

On the other hand, scales are formed when various metal ions present in the sediment due to corrosion on the metal surface or in water quality are combined with anionic chemicals. If the scale is attached, it forms a porous precipitate on the heat transfer surface of the heat exchanger, which hinders the smooth flow of water or, in severe cases, blocks the water pipe, and in some cases causes local corrosion due to the difference in the concentration of dissolved oxygen in the water. Sometimes.

Scale problems can be easily found in various industrial installations using water pipes, including heat exchangers for cooling and air conditioning installed in actual industrial sites, which not only impair the cooling circulation system but also cause serious problems in thermal efficiency, resulting in enormous economic losses. It is raising.

In order to solve the above problems, the cooling water treatment agent is indispensably used, and is currently widely used in all industrial sites.

Conventionally, the water treatment agent containing high concentration of phosphate is widely used as the cooling water treatment agent. However, such water treatment agent maintains relatively high phosphorus content, which increases red tide and green algae by phosphorus when the cooling water is discharged from the system. (High Conductivity) When applied in cooling systems in water quality conditions, there is a problem of generating scale composed of calcium phosphate.

As a conventional water treatment composition, the technique using chromium salts was widely used in the 1960s, but the use of chromium salts is regulated because it causes environmental pollution by heavy metals and is highly toxic to the human body.

Recently, examples using phosphates, azole compounds, acrylic polymers, maleic polymers, lignin, tannins, etc. have been published and are widely used in industrial fields.

For example, U.S. Patent No. 4,134,959 describes a water treatment agent composition using an azole compound and phosphate, and U.S. Patent No. 4,149,969 describes zinc salts, molybdates, manganese salts, nickel salts, azole compounds, and phosphonates. Compositions containing zinc salts, cellulose gums and phosphonates are disclosed, and US patent nos. 4,411,865 using zinc salts, chromium salts, phosphates and acrylate copolymers. A technique has been reported, and in US Pat. No. 5,227,133, a cooling water treatment technique with a composition of zinc salt, molybdate and phosphate is reported.

However, the conventional water treatment technologies can not be expected to achieve satisfactory performance in the ability to suppress the scale at an input concentration of 10 ppm or less, and its use is regulated due to various problems such as pollution generation, human toxicity, and stability.

Accordingly, the inventors of the present invention have made efforts to solve the above problems, and when the mixture of two organic phosphates, acrylate copolymer and water is used as a component of the water treatment composition, the concentration of the water treatment composition is about 10 ppm. The present invention has been found to be excellent in inhibiting scale in divalent metal salts, particularly in cooling systems with high calcium hardness.

Accordingly, an object of the present invention is to provide a method for treating scale formation suppression water for a cooling system, which is more safe due to excellent scale suppression effect, and does not use heavy metal, thereby reducing the risk of various problems.

The present invention is selected from hydroxy ethylidine diphosphonic acid, hydroxy phosphono carboxylic acid, amino trimethylene phosphonic acid, phosphono butane tri carboxylic acid and ethylene diamine tetra methylidine phosphonic acid in cooling water for a cooling system. 0.1-40 weight% of 2 types of organic phosphate compounds; 0.1 to 30% by weight of an acrylate copolymer represented by Formula 1; And an underwater scale formation inhibiting water treatment method of introducing a cooling system scale preventing water treatment composition comprising 30 to 99.8 wt% of water at a concentration of 10 ppm or less.

In Formula 1, R ₁ and R ₂ are the same or different and are hydrogen, an alkyl group, a hydroxyl group, or a phosphono group, and X and Y are each independently an integer of 1 to 15.

Hereinafter, the present invention will be described in detail.

According to the present invention, the composition comprising the organic phosphate compound and the acrylate copolymer has a high calcium hardness at a concentration of 10 ppm or less, which is a smaller amount than that of the conventional water treatment composition, when the concentration is at least 50 ppm. The present invention relates to a scale formation inhibiting water treatment method for a cooling system that can effectively suppress scale formation of a phosphorus cooling system.

Hereinafter, it will be described in more detail for each component constituting the water treatment composition of the present invention.

 The water treatment composition of the present invention comprises 0.1 to 40% by weight of an organic phosphate compound, 0.1 to 30% by weight of an acrylate copolymer and 30 to 99.8% by weight of water.

The organic phosphate compound is a mixture of two selected from hydroxy ethylidine diphosphonic acid, hydroxy phosphono carboxylic acid, amino trimethylene phosphonic acid, phosphono butane tri carboxylic acid, and ethylene diamine tetra methylidine phosphonic acid. Preference is given to using.

That is, the organic phosphate compound used in the present invention is particularly excellent in inhibiting calcium salt scale formation, and is used in an amount of 0.1 to 40% by weight, more preferably 1.0 to 35% by weight, based on the total amount of the water treatment agent composition of the present invention. At this time, if the concentration of the organic-based phosphoric acid compound is less than 0.1% by weight, the water treatment effect is lowered, and if it exceeds 40% by weight, economic efficiency is poor.

The acrylate copolymer has a function of suppressing scale formation in water, and it is preferable to use one having the structure of Chemical Formula 1. The acrylate copolymer is suitably maintained at 0.1 to 30% by weight, more preferably 1.0 to 20% by weight, based on the total amount of the water treatment composition. In this case, when the concentration of the acrylate copolymer is less than 0.1% by weight, the effect of inhibiting scale formation is insignificant, and when the concentration of the acrylate copolymer is more than 30% by weight, it is not economical, and when the cooling water is discharged into the river, the COD of the discharged water is high.

Although the above water treatment agent composition is introduced into the cooling water for the cooling system at a concentration of 10 ppm or less, the effect of preventing scale formation is sufficiently expressed even with the addition of 2 to 6 ppm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-3 and Comparative Examples 1-5

Next, the water treatment agent composition consisting of the components and contents shown in Table 1 was maintained at a concentration of 2 ppm and 6 ppm in the test water of Table 2, and then the next scale inhibition performance was measured.

division Example (% by weight) Comparative example (wt%) One 2 3 One 2 3 4 5 Organic Phosphate Compounds ¹⁾ 20 15 10 10 20 0 30 25 Organic phosphate compounds ²⁾ 10 15 20 10 20 20 0 15 Acrylate copolymer ³⁾ 10 15 20 15 20 20 10 0 Azole compound ⁴⁾ 0 0 0 5 5 0 0 0 water 60 55 50 40 35 60 60 60 1) Phosphonobutane tricarboxylic acid (manufactured by PBTC, BAYER) 2) Hydroxyethylidene diphosphonic acid (HEDP, manufactured by LONZA) 3) Belkrene 400 (manufactured by BIOLAB) 4) Benzotriazole (Nantong chemical Four products)

division Water quality One 2 3 pH 8.0 7.7 7.5 Calcium Hardness (ppm) 150 200 250 Methyl Orange-Alkalido (ppm) 100 100 100 Magnesium hardness (ppm) 15 20 25 Chlorine Ion (ppm) 40 40 40

In Table 2, pH was adjusted with 0.1 N sodium hydroxide solution and 0.05 N sulfuric acid solution, and calcium hardness (Ca-H) was adjusted with calcium chloride. In addition, methyl orange-alkalinity (M-Alkalinity) was adjusted to sodium bicarbonate, magnesium hardness (Mg-H) was adjusted to magnesium sulfate, Chloride (Chloride) chlorine ion concentration due to calcium chloride used to control calcium hardness The deficiency was adjusted using sodium chloride.

Experimental Example: Scale performance measurement (extreme carbonate hardness method)

The scale inhibitory performance of the water treatment agent compositions of Examples 1 to 3 and Comparative Examples 1 to 5 was measured by the following extreme carbonate hardness method.

That is, after maintaining the water treatment compositions of Examples 1-3 and Comparative Examples 1-5 at 2 ppm and 6 ppm in the test water of Table 2, total alkalinity and chlorine ions (Cl ⁻ ) by the extreme carbonate hardness method. The concentration was measured.

In the test method of the extreme carbonate hardness method, 1L of the test solution was taken into a beaker, and the water temperature was maintained at 45 ± 1 ° C., followed by evaporation and concentration. Measure the ^{concentration-by} during the experiment periodically collected water sample in the beaker (Experiment initially can increase the sampling interval), total alkalinity and chlorine ions (Cl) to obtain the intrinsic hardness and carbonate concentrations.

Ultimate carbonate hardness (Δb) was measured using the following equation 1, the concentration is measured using the equation (2).

In Equation 1, and 2, △ b is the intrinsic carbonate hardness, Cl ^- X is Cl in the sample ^- the concentration (mg / L), ^Cl-B is the initial Cl ^- is the concentration (mg / L) of, AX is The total alkalinity of the sample (Total-Alkalinity, mmol / L) and AB is the initial total alkalinity (mmol / L).

By measuring the concentration when the ultimate carbonate hardness (Δb) is 0.5 mmol / L obtained by the above formula (1) means that the higher the concentration, the better the scale inhibitory performance. Thus, the concentration when the ultimate carbonate hardness (Δb) is 0.5 mmol / L is shown in Table 3 below.

division Dosage Water quality (concentration) One 2 3 Example 1 2 ppm 4.1 3.6 3.3 Example 2 3.9 3.6 3.2 Example 3 3.9 3.4 3.2 Example 1 6 ppm 5.0 4.8 4.5 Example 2 4.7 4.6 4.3 Example 3 4.6 4.4 4.0 Comparative Example 1 2 ppm 2.5 2.3 2.0 Comparative Example 2 2.8 2.5 2.1 Comparative Example 3 1.9 1.4 1.3 Comparative Example 4 2.3 2.0 1.6 Comparative Example 5 2.1 1.9 1.5 Comparative Example 1 6 ppm 3.2 3.0 2.7 Comparative Example 2 3.3 3.2 2.9 Comparative Example 3 2.4 2.1 1.7 Comparative Example 4 2.9 2.8 2.5 Comparative Example 5 2.6 2.4 2.0

As shown in Table 3, the concentration of the water treatment agent composition of Examples 1 to 3 of the present invention using the extreme carbonate hardness method it can be seen that the concentration is significantly improved compared to Comparative Examples 1 to 5.

As described above, according to the scale formation inhibiting water treatment method for the cooling system of the present invention is excellent in the anti-scaling capacity in the water pipe of the cooling system, in particular, it is possible to effectively suppress the formation of scale of the divalent metal salt, and has been used as a conventional cooling water treatment agent Their input concentration is at least 50 ppm, but it can be used easily and safely because it suppresses scale generation even below 10 ppm.

Claims (1)

In the cooling water for the cooling system, 0.1 to 40 organic phosphoric acid compounds selected from hydroxy ethylidine diphosphonic acid, hydroxy phosphono carboxylic acid, amino trimethylene phosphonic acid, phosphono butane tri carboxylic acid and ethylene diamine tetra methyllidine phosphonic acid weight%; 0.1 to 30% by weight of an acrylate copolymer represented by Formula 1; And a water treatment composition for preventing cooling system scale containing 30 to 99.8% by weight of water at a concentration of 10 ppm or less. [Formula 1]

In Formula 1, R ₁ and R ₂ are the same or different and are hydrogen, an alkyl group, a hydroxyl group, or a phosphono group, and X and Y are each independently an integer of 1 to 15.