KR100310167B1 - Descaling agent for open circulation cooling system - Google Patents

Abstract

PURPOSE: An antiscaling agent of preventing scale deposition on pipes has superior performance in water without toxicity to aqueous living creatures when discharged into water bodies. CONSTITUTION: The descaling agent comprises 0.5-30wt.% of an orthophosphate selected from the group consisting of NaH2PO4, Na2HPO4, Na3PO4 and H3PO4; 0.5-40wt.% of a polyphosphate selected from the group consisting of sodium hexametaphosphate, sodium pyrophosphate and potassium pyrophosphate; 0.1-50wt.% of a phosphonate selected from the group consisting of phosphonobutane tricarboxylic acid, hydroxyethylidene diphosphoric acid, hydroxy-phosphonocarboxylic acid and aminotrimethylene phosphonic acid; and 0.1-50wt.% of acrylate copolymer represented by chemical formula I.

Description

Water treatment composition for inhibiting corrosion and scale formation of open circulation cooling system and water treatment method using the same

[Industrial use]

The present invention relates to a water treatment agent composition for inhibiting corrosion and scale formation caused by the cooling water of an open circulation cooling system and a water treatment method using the same, and more particularly, orthophosphate, polyphosphate, phospho It relates to a novel water treatment composition comprising a phosphonate and an acrylate polymer represented by the following general formula (I), and a water treatment method using the same.

In the above formula, X and Y are each independently an integer of 1 to 15.

[Private Technology]

Corrosion generally refers to a phenomenon occurring under conditions involving water, in which various ions contained in water are reduced on the metal surface, such that an equivalent amount of metal is ionized (oxidized) and lost. At this time, the place where both reactions occur is different to form a local battery.

The scale is formed from the deposition of solutes in the concentrate, the attachment of strong acid salts such as calcium sulfate, the attachment of weak acid salts such as calcium carbonate, the attachment of organic salts, or the attachment of a polymeric material by polymerization condensation of organic materials. Say). The scale not only lowers the thermal conductivity of the metal pipe but also causes local corrosion of the metal pipe.

In the water pipes of various industrial facilities installed in actual industrial sites, the corrosion and scale occur, which not only causes a great obstacle to the circulation system, but also shortens the life of the facilities.

In particular, since the open circulation cooling system is concentrated, salts are concentrated to easily form scales in the metal pipes, and local corrosion is likely to occur. Moreover, in the open circulation cooling system for fiber polymerization, as the inflow of organic matter, which is a byproduct of the polymerization reaction, increases, the organic matter acts as a nutrient source of the microorganism, and the hydrogen ion concentration in the cooling water increases due to the metabolism of the microorganism. As a result, overall corrosion on the metal pipe surface is likely to occur.

In order to suppress the corrosion and scale formation, conventionally, a chromium salt is used as the water treatment agent composition, a phosphate and an azole compound, an acrylic polymer, a maleic polymer and a phosphate salt, lignin and tannin, or the like. In particular, zinc salts are known to be useful for preventing corrosion in small amounts by inhibiting oxidation or anode reactions during corrosion reactions. US Patent No. 4,149,969 discloses zinc salts, molybdate salts, manganese salts, nickel salts, and azole compounds. The composition consisting of phosphonates is disclosed in US Pat. Nos. 4,324,684 and 4,411,865, which comprise zinc salts, chromium salts, phosphates, and acrylate copolymers. Disclosed are compositions each consisting of.

However, the above water treatment agent compositions can not be expected to achieve satisfactory performance to suppress corrosion and scale formation, in particular, in the case of chromium salt has a number of problems in terms of pollution, human toxicity, and stability, its use is regulated, zinc Salt has a problem that has a fatal effect on fish and shellfish.

An object of the present invention is to solve the above problems, to provide a novel water treatment agent and a water treatment method using the same, which can achieve an effect of suppressing excellent corrosion and scale formation, as well as simple and safe use.

[Means for solving the problem]

In order to achieve the above object, the present invention is 0.5 to 30% by weight of orthophosphate. Provided is a water treatment composition for inhibiting corrosion and scale formation of an open circulation cooling system comprising 0.5 to 40 weight percent polyphosphate, 0.1 to 50 weight percent phosphonate, 0.1 to 50 weight percent acrylate polymer and remainder. .

The orthophosphate is selected from the group consisting of sodium monophosphate (NaH ₂ P0 ₄ ), sodium diphosphate (Na ₂ HP0 ₄ ), sodium triphosphate (Na ₃ P0 ₄ ) and phosphoric acid (H ₃ P0 ₄ ) It is preferable.

The polyphosphate is preferably selected from the group consisting of sodium hexametaphosphate, sodium pyrrophosphate and potassium pyrrophosphate.

The phosphonate is phosphonobutane tricarboxylic acid, hydroxyethylidene diphosphonic acid, hydroxyphosphonocarboxylic acid, and aminotrimethylene phosphonic acid (aminotrimethylene phosphonic acid) is preferably selected from the group consisting of.

The acrylate polymer is preferably a compound represented by the following formula (1).

[Formula 1]

In the above formula, X and Y are each independently an integer of 1 to 15.

The present invention also provides a water treatment method for inhibiting corrosion and scale formation of the open circulation cooling system including the step of introducing the water treatment agent composition into the water pipe of the open circulation cooling system.

Hereinafter, the present invention will be described in detail.

The orthophosphate acts to suppress the anodic reaction (oxidation reaction) and the cathode reaction (reduction reaction) during the corrosion reaction, and is 0.5 to 30% by weight, more preferably 1.0 to 25% by weight, based on the total amount of the water treatment agent composition. maintain. If the concentration of orthophosphate is less than 0.5% by weight, the anticorrosive ability is lowered, and if it exceeds 30% by weight, there is a risk of forming a scale in some cases.

The polyphosphate serves to suppress the negative electrode reaction during the corrosion reaction, and is maintained at 0.5 to 40% by weight, more preferably 1.0 to 35% by weight based on the total amount of the water treatment agent composition, and the concentration of the phosphonate is 0.5. If it is less than the weight%, the effect of water treatment will fall, and if it exceeds 40 weight%, it will be inferior in economy.

The phosphonate acts to inhibit the cathodic reaction and calcium salt scale formation during the corrosion reaction, it is maintained at 0.1 to 50% by weight, more preferably 1.0 to 45% by weight based on the total amount of the water treatment agent composition. If the concentration of the phosphonate is less than 0.1% by weight, the effect of water treatment is lowered, and if it exceeds 50% by weight, economical efficiency is lowered.

The acrylate copolymer serves to inhibit scale formation, and is maintained at 0.1 to 50% by weight, more preferably 1.0 to 45% by weight, based on the total amount of the water treatment agent composition. If the concentration of the acrylate copolymer is less than 0.1% by weight, the effect of water treatment is insufficient, and if it exceeds 50% by weight, the economy is inferior to the effect enhancement.

The water treatment composition of the present invention as described above can be used more effectively to suppress the corrosion and scale formation that can occur in various industrial water pipes, such as cooling towers, heat exchangers, in particular, open circulation cooling system that is prone to corrosion and scale formation by concentrated operation It can be used as a water treatment agent of the cooling water.

EXAMPLE

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments for explaining the construction and effects of the present invention, and the present invention is not limited to the following examples.

[Examples 1-3]

After keeping the water treatment agent having the composition of Table 2 below at 100 ppm in the test water having the water quality of Table 1 below, the carbon steel test piece (0.218dm ² ) at 45 ° C for 5 days at a rotational speed of 170rpm, and then the corrosion rate ( mdd, mg / (dm ² · day)).

1: It was adjusted with 0.5N sodium hydroxide solution and 0.5N sulfuric acid aqueous solution.

2: adjusted with calcium chloride.

3: adjusted with magnesium sulfate.

4: adjusted with sodium chloride.

1: brand name; Belclene 400, FMC

2: hydroxyethylidine diphosphonic acid (trade name; Unihib 106, from LONZA)

[Comparative Examples 1-3]

In Examples 1 to 3, except that the water treatment agent having a composition of Table 3, instead of the water treatment agent having a composition of Table 2 was used in the same manner.

1: brand name; Belclene 400, FMC

2: hydroxyethylidine diphosphonic acid (trade name; Unihib 106, from LONZA)

The results of the Examples and Comparative Examples are shown in Table 4 below.

According to the said Table 4, it turns out that the corrosion rate in Examples 1-3 with respect to the test water which has the water quality of said Table 1 is significantly smaller than the corrosion rate in Comparative Examples 1-3.

Therefore, the water treatment agent and the water treatment method using the same according to the present invention not only have an excellent effect of preventing scale by inhibiting the formation of scale in the water pipe of the open circulation cooling system and suppressing the anode and cathode reactions during the corrosion reaction, and are simple and safe. Can be used.

Claims (5)

0.5-30% by weight of orthophosphate; 0.5-40 wt% polyphosphate; 0.1-50% by weight of phosphonate; 0.1 to 50 wt% of an acrylate polymer represented by Formula 1 [Formula 1]

Wherein X and Y are each independently an integer of 1 to 15; And a water treatment agent composition for inhibiting corrosion and scale formation of an open circulation cooling system comprising water as remainder. The method of claim 1, wherein the orthophosphate is sodium monophosphate (NaH ₂ P0 ₄ ), dibasic sodium phosphate (Na ₂ HP0 ₄ ), trisodium phosphate (Na ₃ P0 ₄ ) and phosphoric acid (H ₃ P0 ₄ ) Water treatment agent composition selected from the group consisting of. The water treatment composition of claim 1, wherein the polyphosphate is selected from the group consisting of sodium hexametaphosphate, sodium pyrrophosphate and potassium pyrrophosphate. According to claim 1, The phosphonate is phosphonobutane tricarboxylic acid (phosphonobutane tricarboxylic acid), hydroxyethylidene diphosphonic acid (hydroxyethylidene diphosphonic acid), hydroxyphosphonocarboxylic acid (hydroxyphosphonocarboxylic acid), And aminotrimethylene phosphonic acid (aminotrimethylene phosphonic acid) water treatment agent composition selected from the group consisting of. A water treatment method for inhibiting corrosion and scale formation of an open circulation cooling system comprising the step of introducing the water treatment agent composition according to claim 1 into a water pipe of the open circulation cooling system.