JPS5959298A - Composition and method of suppressing scale - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water treatment method, particularly 1. The force V for suppressing and removing solid deposits in industrial heating and cooling equipment (11).

Equipment that handles water in the industry, such as boilers for steam generation, heaters using high-temperature water, heat exchangers, cooling towers, desalination equipment, washing equipment, and pipelines.

Various impurities are contained in the water used in the scum cleaning device and the devices attached thereto. These impurities typically include alkali 1-class cations, such as calcium, helium 1\, and magnesium ions, as well as several anions, such as ToiKM ions, carbonate ions,
Sulfate ion, C1. Contains oxalate ion, phosphate ion, silicate ion, and fluoride/r-ion. These anions and cations are at pH 1 pressure of the system or temperature 1'h.
, or combined with the presence of other ions to form an insoluble product to form a precipitate. The most pervasive impurities found in commercial water supplies are ions that harden the water, such as calcium, magnesium, and rXH ions. In addition to precipitating as 'r-'RM salts, the calcium and magnesium ions present in the liquid and the iron or copper ions react with sulfur, sulfuric acid, and sulfuric acid to form their respective insoluble forms. Forms complex salts. These solid reaction products accumulate and form scale on the surfaces of the equipment. These waters also contain various solids, such as mud, viscous-11, iron oxides,
This includes silt, sand, and other mineral matter, as well as dead microorganisms, which accumulate in the equipment as sludge. Iron oxides are present in the feed water and are formed by corrosion of metal surfaces that are in contact with the water. The sludge mixes with the scale sedimentation V, and this sedimentation converts the sludge particles into [t,i], producing a strongly adhesive scale.

Sludge and scale sedimentation equipment with low flow rate,
1! , which significantly reduces heat transfer efficiency by restricting water circulation and blocking water from heated surfaces. In addition to interfering with heat transfer and fluid flow, deposits can easily corrode metal surfaces because they cannot effectively contact the surface. Sediment also causes the growth of bacteria. Removal of deposits requires delays or interruptions in equipment operation, resulting in increased costs. Relatively high temperature water and hard water in boilers for generating water and air tend to form scales on fat. Excessive scale or deposits can cause localized overheating and destroy the boiler.

External treatments, such as water softening, flocculation, and cooling, do not adequately remove soil and solid products;
Various internal chemical treatments have been used to prevent and remove scale and sludge in native systems. To chemically treat a boiler, it is generally necessary to use a combination of precipitants and solidification modifiers to keep the solids in the boiler water in a suspended state, and to effectively remove them along with the water withdrawn from the boiler as withdrawal water. be. The precipitants used for calcium salts are sorter ash and sodium phosphate. Magnesium is precipitated as magnesium hydroxide by adjusting the alkalinity of boiler water.

various polycarboxylic acids and other water-soluble polar polymers,
For example, acrylic polymers have been used as quality regulators in industrial waters. The presence of small amounts of these polymers improves the fluidity of the sludge, and instead of the hard, dense crystals that form on the surface, amorphous, brittle, serrated precipitates form.

The finely dispersed solid particles stay in a suspension shape of 7 g and are carried away from the yarn by the water flow or the withdrawn water.

Phosphonic acid compounds are widely used in water treatment as V-depressants and have extremely low thresholds compared to the chemical quantities required to chelate or toesterify with scale-forming cations. It is effective.

Reaves and Ing
The scale inhibitor for aqueous systems described in Moxibustion National Patent No. 2,061,249 of ham') consists of a water-soluble phosphon hydrochloride compound and a vinyl addition type copolymer or a water-soluble salt thereof. The phosphonic acid compound contains at least one carboxylic acid group and at least one phosphonic acid group, with at least three acid groups attached to carbon atoms. The copolymers are generally derived from ethylenically unsaturated acids, such as maleic acid (or its anhydride), acrylic acid, and methacrylic acid, and have carboxyl or carphonic anhydride groups and sulfonic acid groups. A particularly preferred phosphonic acid group is 2-phosphonobutane-
It is a 1,2,4-1 dicarboxylic acid. &f Suitable copolymers include copolymers of methacrylic acid and 2-acrylamido-2-methylpropanesulfonic acid, and copolymers of styrenesulfonic acid and maleinoic acid. In the formula representing the sulfonic acid group-containing unit of the it' ff1 combination described in the patent, R2 is hydrogen and Y is a sulfonic acid group,
When the ethylenically unsaturated center is maleic anhydride, the copolymer is a copolymer of vinyl sulfonic acid and maleic anhydride. In Examples □, a copolymer of methacrylic acid and 2-acrylamido-2-methylpropanesulfonic acid.

The combination of phosphonic acid and phosphonobutanecarphonic acid has a similar effect, but the combination of this polymer with other phosphonic acids such as nitrilotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, and hexamethylene diamine tetramethylene phosphonic acid It has been shown that the combination with Sunjin has no synergistic effect.

U.S. Pat. Nos. 4,255,259 and 4,306°9 to Iwa and Cuisia.
No. 91 r3 describes an aqueous scale inhibitor comprising a copolymer of styrene sulfonic acid and maleic anhydride or maleic acid, and a water-soluble phosphonic acid or a salt thereof. A variety of phosphonic acids can be used, including hydroxy/enaritensiphosphonic acid and amidomethylene phosphonic acid.

The composition for inhibiting scale formation in an aqueous system of the present invention is (
a) Copolymer of maleic acid or its anhydride and vinylsulfonic acid or its water-soluble salt; and (b) General formula 11 4111 In the formula, R is -CH2-P-OH, and n is O-6. x is 1 to 6; or - a phosphonic acid compound of the general formula IJ, where X is -OH or -NH2 and R is an alkyl group having a prime number of 1 to 5; It consists of water-soluble IAA.

The method of inhibiting scale formation in an aqueous system of the present invention is a method of adding the composition of No. 11, which is effective in inhibiting scale, to the system.

According to the present invention, scales, especially those containing carnoum and magnesium phosphates and siliceous iron oxides, are deposited and formed in the north of industrial aqueous metal structures. An excellent way to suppress this is provided. The compositions and methods of the present invention are effective when used at high temperatures and pressures in waterless boilers, and the copolymer remains dissolved even in water with high hardness and alkalinity. There is. According to the present invention, the L4J value effect in suppressing the formation of metal salt crystals can be obtained, and it is possible to prevent them from adhering to the heat transfer surface even at low treatment concentrations.

In the present invention, water-soluble aminoalkylene phosphonic acids, hydroxy or aminoalkylidene phosphonic acids, or water-soluble versions thereof are used. The most preferred compound is aminotri(methylene 5-osphonic acid),
Hydroxyethylene 1.1-cyphosphone and its water-soluble salts. This alkylidene diphosphonic acid is commercially available and its preparation, along with the preparation of other phosphonic acids, is described, for example, in U.S. Pat.
．． 454 Gin and No. 3,297.5'78. The most preferred aminophosphonic acids are commercially available and their preparation, along with other similar methods of making phosphonic acids, is described in U.S. Pat.
No. 298,956. Other suitable phosphonic acids having the formula 7 include the following: Ethylenecyaminetetra (methylenephosphonic acid)
, diethylenetriamine penta (methylene phosphonic acid), triethylene tetramine hexa (methylene phosphonic acid), hexamethylene amine tetra (methylene phosphonic acid), amine enalithene diphthonic acid, aminopropylidene diphthonic acid, Hydroxybutylidene diphos dioic acid, hydroxybutylidene diphos dionic acid, and hydroxyhexylidene diphosfus dionic acid.

The composition of the present invention further comprises an aliphatic copolymer of maleinoic acid or its acid anhydride and vinylsulfonic acid or its alkali metal salt. This polymer can be produced by copolymerizing maleic acid or its acid anhydride with vinylsulfonic acid or its alkali metal salt. Conventional addition polymerization methods can be used with light or Mg& group +l'i polymerization initiators. Generally, the copolymerization can be carried out in an inert solvent using a peroxide catalyst, such as hydrogen peroxide or benzoyl peroxide, at a temperature of about 30 DEG to 120 DEG C. The copolymer can be prepared, for example, by combining maleic acid and sodium vinyl sulfonate in solution in the presence of hydrogen peroxide.

Another method of making the copolymers of the invention is to combine a polymerizable monoethyl compound, such as methyl vinyl ether, or vinyl acetate, and hydrolyze the polymer with an alkali or acid (I ), the ether or ester () is substituted with a hydroxyl group, and the polymer is sulfonated by the conventional methods described, for example, in U.S. Pat. No. 2,764,576.The degree of sulfonation can be varied. However, substantially complete sulfonation is preferred.

The relative proportions of vinyl sulfonate and maleic anhydride will depend on the degree of scale control required. Jt1 composites generally contain from about 10 to about 90 mole percent sulfone salt tolerance. Preferably the molar ratio of vinyl sulfonate moieties to moieties derived from maleic acid is from about 0.5:l to about a
:t, about 1-1 to about 2:1 to 41F.

) (The average molecular weight of the polymer is not very large as long as the polymer is water-soluble. Generally, min-f-H is about 500
~100,000. The molecular weight is preferably about 1,
000 to about 25,000. Especially about 6. OoO ~ about 10.
It is 000.

A particularly preferred acid form of the copolymer is of the formula I1. m and n are arranged in an irregular order, m is about 20 to about 70 mol%, and n is about 30
~80 mol%. The molecular weight is t±about 1, ooo to about 25,000.

Phosphonate salts and copolymers are generally used (1) in the form of alkali metal salts, usually sodium salts. Other i!
! Suitable water-soluble salts include potassium, ammonia L., zinc, and lower amine salts. The free acid can also be used; not all acidic hydrogens or all cations need be replaced. That is, the cations are NH4, H
, Na, or a mixture thereof. J (The polymer can be converted into a water-soluble salt in the usual manner.

Although the phosphonic acid compounds and polymers can be added separately to the aqueous system, it is generally convenient to add them together in the form of a composition. The compositions of the present invention generally contain about 0.
1 to about 6 parts by weight of the copolymer and about 0.1 to about 10 parts by weight of the copolymer.
0 parts, preferably about 0.5 to about 5,000 parts of the phosphonoic acid compound. Generally, the polymer and phosphonic acid compound will be in a ratio of about 10:1 to about 1:10. Preferably, a weight ratio of about 4=1 to about 1.4, more preferably about 1:1 is used.

Although the composition can be added as a dry powder and dissolved during use, Ondo is used in the form of an aqueous solution. The solution generally contains from about 1 to about 70% by weight of the composition, preferably from about 1 to about 40% by weight of the composition. Solutions can be created by adding the components in any order.

The amount of M1 component added to the water is less dependent on the scale and the type of aqueous system being treated than the quantitative ψ that is effective in controlling scale. The amount of phosphonate addition ψ depends on the amount of water-hardening and scale-forming compounds present in the system. Generally this value is calculated from the concentration of calcium and therefore the hardness of the water. The addition of copolymer will depend in part on the existing concentration of solids suspended in the system and solids produced in the system. The composition generally contains about 0.01 to about 500 ppm of water in the system, and preferably about 0.1
Added to the aqueous system in an amount of ~50 ppm.

The compositions of the present invention may include or add other ingredients traditionally used in water treatment, such as alkalis, lignin 1 derivatives, other polymers, tannins, other phosphonates, bactericides, and corrosion inhibitors. I can do something. The compositions of the present invention can be added to the water of the system at any location where they can be rapidly and efficiently mixed. Treatment chemicals are added to the formulation or supply water inlet line through which the perspiration water enters the system. Typically, an injection tube is used that is calibrated to periodically or continuously supply a constant amount of water for dispensing.

The present invention is particularly useful in the treatment of water for feeding or dispensing with boilers for water generation. Such boiler equipment typically operates at temperatures of about 298°F to about 637°F and pressures of about 50°F.
~2,000 psig.

The compositions of this invention and their use are illustrated in the following examples, in which all percentages are based on LF4 unless otherwise specified.

Examples 1 and 2 Hydroxyethylidene difluoride or aminetri(methylenephos) 11 and sodium vinyl sulfonate and maleic anhydride, with a molecular weight of 8,000 and sodium vinyl sulfonate 71 An aqueous solution was prepared containing 1 part of the copolymer at a molar ratio of 1.5:1/in/oxygen water. The treatment solution may contain sodium phosphate, sodium sulfate, sodium sulfite, sodium hydroxide, and sodium chloride in amounts sufficient to form a boiler water composition as shown in Table 1 below. In addition, a solution containing the same amount of treatment chemicals other than the composition of the present invention, and a solution containing 1 part of the composition of the present invention containing 1 F of treatment chemicals (+fl-fjj) were prepared.

The slurry handling and scale control properties of these solutions were tested in a small laboratory boiler. This boiler is from the Western Pennsylvania Society of Engineers (Engineers Association).
5ociety of Western Penn5
ylvania)) 15th Annual Meeting of the Japanese Society of Water Quality (Fif
Teenth Annual Water Conference
ence) has three removable tubes as shown in Proceedings, pages 87-10 (1954). The water supplied to this laboratory boiler was tap water from Lake Zurich in Ilyiny, USA.
It was diluted with distilled water so that the total hardness as O3 was 40 ppm, and calcium chloride was added to give a total hardness of 6.1. Feed water and chemical treatment solution were supplied to the boiler at a ratio of 3 volumes of feed water to 1 volume of treatment solution, and the total hardness was 30 pp as Caco.
I set it to m. All treatment solution scaling tests were conducted by adjusting the boiler water withdrawal to 10% of the boiler feed water, concentrating the salts in the boiler water approximately 10 times, and after concentrating the treatment solution 10 times, the boiler water The composition was adjusted to have the composition shown in the table.

Table 1 Sodium hydroxide as Na OH 258 p
T'1llNa2 co3 and 1. Sodium teno carbonate 1
Sodium chloride as 20 ppm NaCl
Fi8] 1) Sodium sulfite as ppmNa2SQ3 50 ppmSodium sulfate as S04Silica as 819 ppm5102
< + Iron as ppmFe
(l Noriy as PpffiP04
% Salt 10-20 PPII scaling tests were conducted for approximately 45 hours at a boiler pressure of 400 ps 1 g. After test P:r, the boiler tubes were individually removed from the boiler, any scale or sediment present within 6 inches of the center of the vessel was scraped off, and placed in a tarred glass bottle. I collected it and weighed it. The test results are shown in Table 2.

Table 2 Test X Additive Feed water Scale Scale number
Inner collar, addition Speed reduction rate (m) (00
) 1 No mouth 0.188 -2
(I) l O,029sa,s3
(II) l O, 14522,
94(III) 1 0.074 6
oye5 (1')+(II) 1 0.
002 98.96 I)+III) 1
0.015 92.01 tons is (g/cubic foot waiting time.

Kimoto blank test.

(Copolymer of sodium vinyl sulfonate and maleic anhydride.

(II) Hydroxyethylidene diphosphonic acid.

<in> Aminotri(methylenephosphonic acid).

The comparative test results for scale formation shown in Table 2 show that the compositions and methods of the present invention are significantly superior to the Chinese and German additions of each component.

Claims (1)

[Scope of Claims] 1. a) Copolymer of maleinoic acid or its acid anhydride and hinyl sulfonic acid or its water-soluble salt: and b) - General formula, where R is -CH2-P- OH is 0 to 6 and X is 1 to 6; or - General formula 4111 In the formula, 1. A composition for suppressing scale formation in an aqueous system, characterized by comprising a phosphonic acid compound; or a water-soluble ta+ thereof. 2. (The polymer and phosphonic acid compound are about 4.1~
Claims p? existing at an east-ψ ratio of approximately 1:4? J1
The composition according to the invention. 3. The composition of claim 1, wherein the copolymer and phosphonic acid compound are present in an HV ratio of about 1:1. 4. Claim 1, wherein the phosphonic acid compound is an amide/alkylene/phosphonic acid compound or a water-soluble salt thereof.
The composition according to item 3. 5. The composition of Claim 4, wherein the phosphonic acid compound is aminotri(methylenephosphonic acid). 6. The phosphonic acid compound is a hydroxy or aninoalkylide 7 phosphonic acid.Claim 1
The composition according to item 6. 7. Phosphonic acid compound is hydroxyethylidene-1
, 1-diphosphonic acid. 8. The composition of claims ff11-3, wherein the molar ratio of vinyl sulfonic acid moieties to maleic acid derived moieties is from about 0.5:1 to about 4:1. 9. The molar ratio of vinyl sulfonic acid moieties to maleic acid derived moieties is from about 1=1 to about 2:l.
Composition according to item 3. 10. The molecular weight of the copolymer is about 1.000 to about 25.00.
4. The composition according to claims 1 to 3, wherein the composition is 0. 11, the molecular weight of j1 combination is about 6.000 to about lo, oo
The composition according to any one of claims 1 to 3, which is o. 12, (a) consisting of maleic acid-free and vinyl sulfonic acid, with a molecular weight of about 6.000 to about 10,000, and a molar ratio of vinyl sulfone S moieties to maleic acid-derived moieties of about 1.1 to about (b) the sodium salt of hydroxyethythylene-1,1-phosphonic acid or aminotri(methylene phosphonic acid); A composition for suppressing scale formation in an aqueous system in which alcohol is present at a ratio of about 1 to 1.13. Polymer; and b) In the general formula (11), R is -CH2P -OHOH, n is O-6, and X is 1 to 6: or -OH or -NH2, R is i
& is an alkyl group with a prime number of 1 to 5: A 1-organic phosphonic acid compound; or a composition consisting of a water-soluble field thereof is added to the system in an amount that suppresses scale. The power to suppress the formation of scale in an aqueous system. Leaving. 14. Approximately 0.0 for the water in the system. O1~about 500ppm jl
The method of claim 1350, wherein the composition is added to the aqueous system in step i. 15, polymers and phosphonic acid compounds are about 4.1
13. The method of claim 13, wherein ff exists with an East 111-ratio of about 1=4. 16. The composition of claim 13, wherein the copolymer and the phosphorescent compound are present in a ratio of about 1:1. 17. The method according to claims 13 to 16, wherein the phosphonic acid compound is an aminoalkylene phosphonic acid or a water-soluble salt thereof. 18. The phosphonic acid compound is aminotri(methylenephosphonic acid).
30's method. 19. Claims 'J' in which the phosphonoic acid compound is a hydroxy or aminoalkylidene phosphonic acid
"; l 3-16JJ'i 1ノ. 20.2 years old The sulfonic acid compound is hydroxyethylidene.
Claim 19 which is 1,1-siphosphonoic acid
How to write beats. 21. The method of claims 13-16, wherein the molar ratio of vinyl sulfone Mm to maleic acid derived moiety is from about 0.5:1 to about 4.1. 22. Claims 13 to 22, wherein the molar ratio of h'-nylsulfonic acid to maleic acid-derived moiety is from about 1 to about 2:1. The method according to item 16. 23, jl: The method of claims 13 to 16, wherein the molecular weight of the polymer is from about 1.000 to about 25.000. 24, the molecular weight of both molecules is about 6.00.0 to about lo,
The method according to claims 13 to 16, which is ooo. 25, (a) Consisting of maleic polyanhydride and vinyl sulfo/acid, one molecule is about 1 or about 6,000 to about 10
, ooo, and vinyl sulfone m r96 min to maley (7: the molar ratio of induction-resistant moieties is about 1 to about 2 = 1) (the sodium salt of the intermediate compound, and (b) hydroxyethyrythene). In this method, an aqueous solution of the sodium salt of 1,1-diphosphonic acid or aminotri(methylenephosphonoic acid) is added to the boiler water at a concentration of about 0.1 to about 50 ppm with respect to the boiler water. How to suppress scale generation.