KR800000198B1 - Anti-scaling agent - Google Patents

Abstract

Scale-preventing and corrosion-inhibiting compositions contg. at least one compound such as inorg. phosphoric acids, phosphonic acids and polyvalent metallic salts, and denatured polymers were described. General formula of denatured polymers was I(OA: 2-4C oxyalkylene group; X:OH, 1-4C alkoxy, or monophosphoric acid group ; a:constant>=1) or II(X: OH, 1-4C alkoxy, or diphosphoric acid group)

Description

Scale inhibitor

INDUSTRIAL APPLICABILITY The present invention relates to an industrial heat exchanger of chemically-cooled water cooling to prevent corrosion, scale, and dirt on a metal surface in contact with water, metal flow through a water system in a cooling water system, and a water channel. In the wall surface or the heat transfer surface such as boiler, seawater desalination apparatus by heating distillation, converter in steel industry, blast furnace, etc., dust collector and piping of dust collector system It relates to a corrosion, scale, and dirt prevention agent in.

For example, water that is supplied to water-cooled heat exchangers and other cooling water systems contains relatively insoluble dissolved inorganic salts such as calcium, magnesium carbonates, and silicate silicates and small amounts of suspended solids. This is included.

In a cooling water system, the cooling effect is achieved by evaporating a portion of the water passing through the cooling tower. However, by dissolution, dissolved inorganic salts and suspended solids in the replenishment water are concentrated in the circulating water, and relatively poorly soluble inorganic substances. Salts precipitate and adhere to the heat transfer surface of the heat exchanger and the like to become scale.

In addition, soil, clay, and organic suspended matter are attached to the parts having a slow flow rate in the heat exchanger, thereby becoming dirty.

In industrial heat exchangers or cooling water systems, since most carbon steel is used, corrosion by dissolved oxygen occurs in neutral water, especially in areas with scales or dirt. Local corrosion is caused by the formation of (酸 素 濃淡 電池).

Such adhesion of scale, dirt, and corrosion products leads to a decrease in the amount of cooling water circulating due to a decrease in heat transfer amount of the heat exchanger or an increase in pressure loss, that is, a decrease in cooling efficiency, and thus to blockage of the heat exchanger tube. In some cases, serious obstacles such as penetrating accidents caused by local corrosion or local corrosion have to be suspended.

Conventional corrosion and scale inhibitors include chromium (VI) compounds which are in the oxidized state in the form of hexavalent, but this is a problem of toxicity and pollution to the environment.

In addition, non-toxic, low-toxic corrosion and scale preventive agents include inorganic poric acid, phosphonic acid and organophosphate esters or water-soluble salts thereof, and Zn (II) ions in water. It is composed mainly of one or two or more compounds selected from salts of polyvalent metals capable of dissociating polyvalent metal ions such as Ni (II) ions, such as guruconic acid, tartaric acid and amino acids. Water-soluble polyamides, aliphatic amines and interfaces of synthetic polymers such as chelating agents such as organic acids, ethylene diamine tetraacetate, nitrile acetate, lignin compounds, tannins, polyacrylic acid salts, and hydrolyzed polyacrylamides There is a composition in which an active agent and the like are blended.

However, these formulations generally have a lower effect than corrosion and scale inhibitors containing chromium (VI) compounds, and when used at low concentrations, the calcium scale inhibiting action tends to increase corrosion. In order to prevent corrosion, it is necessary to add it to a higher concentration. However, the addition of high concentrations of phosphonic acids and organic phosphoric acid, which are known to be difficult to hydrolyze in the case of inorganic poric acid, cause oligosulfate ions generated by hydrolysis in water to form calcium ions and insoluble precipitates, and are difficult to hydrolyze. In the case of esters, in fact, the hydrolysis rate is quite small in the cooling water. On the other hand, phosphonic acids and the organic phosphate esters are the same as calcium ions in alkaline cooling water having high calcium coexistence. It became clear that insoluble precipitates were made and scaled.

In addition, the above-mentioned polyvalent metal ions also coexist with calcium concentration, and in alkaline cooling water having a high pH, it is impossible to maintain a predetermined polyvalent metal ion concentration, and precipitates and scales as hydroxides, phosphates, and posfonates of polyvalent metal ions. Get angry

This phenomenon changes with the temperature of the cooling water and increases with increasing calcium hardness and pH.

Therefore, it is necessary to determine the addition amount of the corrosion and scale inhibitor according to the temperature of the cooling water, and to use the cooling water having low calcium hardness and adjusted pH.

However, in the actual industrial cooling water system, there is a part of a plurality of heat exchangers having different water temperature in one system, and high concentration due to the demand of water consumption in the cooling water system and the reduction of drainage amount. That is, since it tends to operate as a cooling water with a relatively high calcium hardness, and pH adjustment by acid injection is a cumbersome tendency because of its complexity, it is necessary to suppress corrosion in one system and It is not possible to prevent scaling at the same time and efficiently.

Since the present invention relates to a medicament for preventing corrosion, scale and dirt in an aqueous system from which the above-mentioned defects have been removed, an object of the present invention is a system in which water is in contact with a solid surface, and is a scale that precipitates and adheres to this solid surface. And suppressing dirt, and another object of the present invention is to suppress corrosion, scale and dirt on the metal surface in contact with water, and another object of the present invention is to provide a water-cooled industrial heat exchanger and a cooling water system. Corrosion, scale and dirt are suppressed, and pH is not required to be adjusted by acid injection in cooling water having a relatively high calcium hardness, or even if the burden is reduced, sufficient corrosion, scale and It is to provide a drug that can prevent the dirt.

Namely, the present invention is directed to (a) one or two or more compounds selected from inorganic phosphates, polyphonic acids, organophosphates and polyvalent metal salts, and (b) monomers having a carboxyl group and also having an ethically unsaturated defect. Forima containing at least one structural unit, wherein at least a portion of the carboxyl group is modified as in the following general formula (1):

However, OA: C2-C4 oxyalcokin group

X: hydroxyl group, alkoxyl group having 1 to 4 carbon atoms or monovalent phosphate group [above corresponding to formula (1)] or divalent phosphate group corresponding to formula (2)

a: number greater than or equal to 1

It is an anticorrosion, scale, and antifouling agent in an aqueous system characterized by containing and as an essential component.

Inorganic phosphates in the present invention, general formula

xMnOyPeO ₅ (I)

[Wherein M is a monovalent or divalent metal (including an alkali metal and an alkaline earth metal), n is 1 or 2, X / Y is greater than 0 and less than or equal to 3, and all or part of M is substituted with hydrogen The corresponding acid or acid salt may be used.]

Examples of specific compounds include phosphoric acid, polymerized phosphoric acid, and water-soluble salts thereof, and phosphoric acid includes polyphosphoric acid, triphosphoric acid, and the like. Methic acid, such as lean acid, trimetaric acid, and tetramethic acid, and oltralinic acid.

Phosphonic acids are represented by the following general formula (II) or (III).

[Where at least one of R

이고, 다른것은

And the other one

로 부터되는 군(群)에서 고른 어느 하나이다.

Any one chosen from the group from.

n and m are each a number from 1 to 5.

[Where R is

Is one of the groups selected from and m is a number from 0 to 5.

및 탄소수 1∼4의 알킬기로 되는 군(群)에서 고른 어느 것이고, M는 H, NH₅및 알칼리금속으로 되는 군에서 고른 어느 하나이다. 일반식(Ⅱ)로 표시되는 포스폰산류로서는,In General Formulas (II) and (III), X-shape H,

And any one selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, and M is any one selected from the group consisting of H, NH ₅ and an alkali metal. As phosphonic acid represented by general formula (II),

Amino trimethyl phosphonic acid, ethylene diamine tetra methylene phosphonic acid, etc. are aminophosphoric acid, and phosphonic acids represented by general formula (III) are methylenediphosphonic acid and hydroxy etchidene depot. Spanic acid, 1,2.4-carboxyl-2-phosphonobutane, and the like. Organophosphate ester is represented by the following general formula (IV) or (V)

이고, n는 1이상의 수, m는 0 또는 1이상의 수이다.][Where R is an alkyl group having 1 to 8 carbon atoms, X is any one of H, -O-(-AO-)-H, an alkyl group having 1 to 4 carbon atoms, and A is -CH ₂ -CH ₂ -or

N is one or more numbers, and m is 0 or one or more numbers.]

로서, R의 적어도 하나는

이고, X는 H, -OH 또는 탄소수 1∼4의 알킬기의 어느 하나이고, m는 0 또는 1이상의 수이다.[Where R is H or

At least one of R

X is either H, -OH, or an alkyl group having 1 to 4 carbon atoms, and m is 0 or 1 or more.

및

의 한편 또는 양편으로 되어 있다.At least one to substantially all of the hydroxyl groups of the compound represented by the above are substituted with an phosphate group, and the phosphate ester group

And

It is either or both sides of.

As organophosphoric acid ester derived from general formula (IV), phosphoric acid esters, such as methyl phosphate ester, phosphate ester of alkyl alcohols, such as acetyl phosphate ester, methyl cersolver, acetyl cersolver, glycerol, mannitol, sorbitan, etc. There are phosphate esters of a polyoxyalkylated polyhydroxy compound obtained by adding an ethylene oxide to a polyhydroxy compound such as a mold.

As organophosphoric acid ester derived from general formula (V), there exists phosphate ester of each amino alcohol, such as mono, di, and triethanolamine. Inorganic phosphoric acid, phosphonic acid, and organophosphate ester may be a salt, and salts, such as an alkali metal, ammonia, and an amine, are preferable.

The polyvalent metal salts are polyvalent metal salts capable of dissociating polyvalent metal ions such as Zn (II) ions and Ni (II) ions in water, and specifically include zinc chloride, zinc lactate, and nickel lactate.

과 같이 변성되어 있는 것이 필요하다.Next, in the present invention, examples of the carboxyl group-containing unit in the forma include acrylic acid, methacrylic acid, maleic acid, humic acid, itaconic acid, crotonic acid, cinnamic acid, vinyl benzoic acid, and the like. Phosphoric acid and humic acid are effective. Some of the carboxyl groups of these units are represented by the general formula: -CO (OA) aX... (VI) or

It needs to be denatured like this.

OA represents an oxyalkyrene group having 2 to 4 carbon atoms, and specific examples include an oxyethylene group, an oxyfurypyrene group, an oxybutylene group, and the like. It may be made with kalboksil.

In particular, the oxyalkyrene group is preferably an oxyethylene group alone or copolymerized with an oxyethylene group and other oxyalylene groups, and in this case, either block polymerization or random polymerization. The number of oxyalkyrene groups, that is, a is 1 or more, preferably 1 to 10. X is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms (e.g., methoxy, ethoxy, etc.), or a divalent phosphoric acid group (such as any phosphate group includes salts or mono or di-alkylesters) such as monovalent phosphoric acid groups or other X's In particular, a hydroxyl group and a monovalent phosphoric acid group are preferable.

In the case of a divalent phosphoric acid group, the above general formula (VII) is used. The carboxyl group which is not denatured in the carboxyl group may be in the form of a monovalent cation and a salt, and is preferable in that it becomes water-soluble eventually.

Examples of the salt include alkali metal salts (salts such as Li, Na, K), ammonium salts, amine salts (salts such as methylamine, dimethylamine, ethylamine, mono, di, or triethanolamine, methylethanolamine). have. The salt of the unmodified carboxyl group and the monovalent cation formed may be two or more kinds.

In the case of the modified carboxyl group, in addition to the salts described above, esters such as mono, or di-methyl esters, mono or di-ethyl esters, mono or di-furophiles, mono or di-butyl esters, and methyl esters may be used. It can be lifted.

As a specific example of the forima of the present invention,

Acrylic acid / 2-hydroxyethyl methacrylate / methyl acrylate copolymer sodium salt

(Weight ratio 70: 26: 4)

Acrylic Acid / 2-Hydroxy Ethyl Amethacrylate Monophosphate Copolymer Sodium Salt

(Weight ratio 55:45)

Acrylic Acid / 2-Hydroxy Purofil Acrylate / 2-Hydroxy Purofil Acrylate Monophosphate Copolymer Sodium Salt

(Weight ratio 50:10:10)

Acrylic Acid / 2-Hydroxyethyl Methacrylate / Acrylonitrile Copolymer Sodium Salt

(Weight ratio 40:40:20)

Maleic Acid / Acrylic Acid / 2-Hydroxyethyl Methacrylate Copolymer Sodium Salt

(Weight ratio 30:40:30)

Itaconic acid / 2-hydroxyethyl methacrylate / acrylamide copolymer sodium salt

(Weight ratio 40:30:30)

And the like.

The forima in the present invention needs to be a structural unit of the carboxyl group-containing unit (including one modified as in general formula (VI)), but may further include other structural units (hereinafter referred to as arbitrary units). There is a number.

As a monomer for constituting such an arbitrary unit, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, di Styrene-based compounds, such as (meth) acrylic acid esters, such as methylamino (meth) acrylate and dimethylaminoethyl (meth) acrylate, styrene, and (alpha) -methyl styrene, vinyl acetate, a vinyl propionate Aliphatic ester (meth) acrylamide of vinyl alcohol, such as these, (meth) acrylonitrile, etc. are mentioned.

The modification rate of the carboxyl group can be changed over a wide range, usually 10 to 100%, preferably 20 to 50%.

Moreover, although the ratio of the arbitrary units and the thing modified | denatured like the carboxyl group containing unit general formula (VI) can be changed, it is generally 50-99: 50-1 in molar ratio, Preferably it is 80-99: 20: 1. When the molar ratio of any unit exceeds 50, the performance as an antiscaling agent is lowered and is not preferable.

In addition, the forma in the present invention can be produced by various methods, for example, a monomer containing a carboxyl group and a comonomer and a polymerization initiator (for example, a peroxide such as benzoyl peroxide, azobis isobutyronitrile, or the like). In the presence of an azo compound, a perperate such as hydrogen peroxide, and the like.

At this time, in order to modify a carboxyl group, the method of modifying and polymerizing a monomer beforehand and the method of superposing | polymerizing without denaturing a monomer and modifying after polymerization can be employ | adopted.

However, in general, since the method of modifying the polymer after producing the polymer has a high viscosity, it is difficult to operate the reaction. Therefore, it is preferable to perform a monomer having a relatively low molecular weight.

The forma in the present invention obtained by the above method has a colorless or pale yellow liquid or solid, and the viscosity at 30 ° C. of the 50% aqueous solution is 100 to 20,000 centipoise.

In the present invention, one or more compounds of inorganic phosphates, phosphonic acids, organic phosphates, water-soluble salts of these (hereinafter phosphorus compounds), polyvalent metal salts, and the aforementioned polymarwa are added to the aqueous system. Forima may be injected continuously or intermittently in a quantitative and independent manner, independently of these drugs, and treated in combination with a phosphorus compound and a polyvalent metal salt. This may be injected continuously or intermittently into the water system.

Phosphorus-based compounds or polyvalent metal salts are used to prevent corrosion and scale in the same manner as conventional methods.

For example, a phosphorus compound or a polyvalent metal may be added to an aqueous system where corrosion or scale occurs, and the required anticorrosive concentration and anti-scale concentration may be maintained.

The phosphorus compound or polyvalent metal salt may be added continuously or intermittently. For example, 1 to 100 ppm (as PO ₄ ) is added in the phosphorus compound and 1 to 50 ppm (as metal ion) in the polyvalent metal salt. When the anticorrosive coating is mainly used, for example, about 20 to 500 ppm may be added, and a small amount of chemical may be added thereafter to maintain the anticorrosive coating.

In addition, in the present invention, iron or steel corrosion inhibitors conventionally used for phosphorus compounds, polyvalent metal salts, and forma, or corrosion inhibitors, scale and dirt inhibitors of metals such as steel and steel alloys, metals An ion blocking agent etc. can be used together according to the intended use.

Such corrosion inhibitors include organic salts such as inorganic salts such as chromates, dichromates, tungsten salts, molybdates, acetates, borate salts, silicates, oxycarboxylic acids, amino acids, caterchols, and aliphatic amino acids. Heterocyclic compounds, such as a compound, derivatives thereof, various surfactant, benzotriazole, and melkaft benzothiazole, are mentioned.

Examples of scale and dirt inhibitors include polysaccharides such as ligrin derivatives, tannic acids and starches, derivatives thereof, sodium polyacrylate, and partial hydrolysates of amide polyacrylic acid. Examples of the metal ion blocking agent include polyamines such as ethylene diamine and diethylene triamine, and polyamine carboxylic acids such as nitriroacetic acetic acid, ethylene diamine tetraacetic acid, and triethylene triamine oxyacetic acid. The addition amount of the forima in the present invention to the aqueous system is based on the water quality such as calcium hardness, M-alkalinity and pH of the aqueous system, the maximum temperature of the water temperature in the aqueous system, and the like. It depends on the concentration of polyvalent metal ions that need to be kept stable in water, and is determined individually. Usually, it is effective enough at 0.1 to 1,001 ppm. However, when the concentration of phosphorus compound and polyvalent metal is high, it is necessary to carry poly It is preferable to add 30 to 300 ppm of hemp, and when the concentration of the phosphorus compound and the polyvalent metal is relatively low, it is preferable to add about 1 to 50 ppm of the forma at the time of fat or oil input of the anticorrosive. As described above, the present invention can improve the anticorrosive effect by using the phosphorus-based compound and / or the polyvalent metal salt and the forma as described above, and can suppress the generation of scale and dirt. It is thought that this is to significantly inhibit the precipitation of the forma phosphorus-based compound or polyvalent metal as a poorly soluble compound, and thus prevents the occurrence of scale or dirt in the water system and at the same time the phosphorus-based compound and / or polyvalent metal in the water. The necessary concentration can be maintained and sufficient anticorrosive effect can be exerted.

This effect is particularly exhibited even in a system having a high hardness component and a high pH, so that the present invention can be applied to a place where a conventional application is difficult or a place where the effect is small.

Even if it is applied to a system where the water temperature changes again, if the necessary concentration is added to a low temperature place, it can be prevented even at a low or high water temperature, and no phosphorous compounds or polyvalent metals precipitate and scale, Therefore, the same problem as the conventional one does not occur.

Next, an Example demonstrates this invention.

Each embodiment has a heat transfer area is about 0.25m, and to step ² of the heat exchanger journal (一基) holds quantity (水量) open recirculating cooling water system of the cooling water model in 0.45m ^3, a heat exchanger of the carbon steel tyuwoo beunae 0.5m / The circulating water flowing at the sec flow rate was heated on the Siel side by the circulating water and steam flowing countercurrently.

The inlet temperature of the steam is 130 to 140 ° C, the outlet temperature is 90 to 100 ° C, the inlet temperature of the circulating water is 30 ° C, and the outlet temperature is 55 ° C.

In addition, the heat quantity at this time is 66.000 Kca1 / m <^2> / hr. As replenishment water, tap water of Yokohama-shi of average water quality as shown in Table-1 was used.

The addition of the medicament was continuously injected quantitatively into the cooling tower feet, and the predetermined concentration was maintained in the circulating water. According to the present invention, the adhesion rate of the scale attached to the heat exchanger tube (mg / cm ² / month) and the corrosion rate of the mild steel test specimen immersed in the return pipe of the model cooling water system (mg / dm ² / day) Was evaluated.

TABLE 1

[Examples 1-6 and Comparative Examples 1-4]

The model cooling water system was operated without a forced blow, and the test period was two days until the water quality of the circulating water was twice as high as that of the make-up water.

The chemical | medical agent was added to cooling water system pit to a comparatively high concentration as shown in Table-2, and the adhesion rate and the corrosion rate were measured. According to the present invention, the measurement results show that the effect on suppression of corrosion, scale and dirt is remarkably improved compared to the conventional method.

[Examples 7-12 and Comparative Examples 5-11]

The model cooling water system was operated under the same operating conditions as shown in Example 1 for a minimum of two days, and the drug concentration was maintained at a relatively high concentration. Thereafter, the amount of added chemicals shown in Table 3 was adjusted so that the water quality of the circulating water was twice as high as that of the replenishing water. After the 30-day test period, the adhesion and corrosion rates are measured and the results are shown in Table-3.

[Examples 13-17 and Comparative Examples 12-17]

The first two days were operated in the same manner as the operating conditions shown in Example 1, after which the water quality of the circulating water was equivalent to five times the quality of the replenishment water, and the amount of forced blow and the amount of the chemicals shown in Table-4. Was adjusted.

After the 30-day test period, the adhesion rate and corrosion rate are measured and the results are shown in Table-4.

TABLE 2

Porima A: acrylic acid / 2-hydroxyethyl methacrylate / methyl acrylate copolymer sodium salt

Weight ratio 70: 26: 4)

Forima B: acrylic acid / 2-hydroxyethyl methacrylate monophosphate copolymer sodium salt

(Weight ratio 55:45)

Forima C: acrylic acid / 2-hydroxyethyl metaacrizate / acrylonitrile copolymer sodium salt

(Weight ratio 40:40:20)

TABLE 3

Forima A, Forima B and Forima C are the same as in (Note) of Table 2.

TABLE 4

Organophosphate A: Phosphate of triethanolamine

Organophosphate B: Oxyethylated glycerol phosphate ester

Claims (1)

One or two or more compounds selected from inorganic phosphates, phosphonic acids, organic phosphates, and polyvalent metal salts, and carboxylic groups, and forma including structural units derived from monomers having an ethylene unsaturated bond. Forima at least part of the carboxyl group is modified as in the following general formula Formula (1): -CO (OA) aX or (2):

However, OA: C2-C4 oxyalkylene group X: hydroxyl group, a C1-C4 alkoxy group, or monovalent phosphoric acid group [above, (1)] or divalent phosphoric acid group [corresponding to Formula (2)] a: number greater than or equal to 1 Anticorrosive, scale, and anti-fouling agent in an aqueous system characterized by containing as an essential component.