CN110803784A - Composite corrosion and scale inhibitor containing water-soluble silicate, application thereof and method for inhibiting corrosion of circulating cooling water containing sulfur - Google Patents

Composite corrosion and scale inhibitor containing water-soluble silicate, application thereof and method for inhibiting corrosion of circulating cooling water containing sulfur Download PDF

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CN110803784A
CN110803784A CN201810887141.8A CN201810887141A CN110803784A CN 110803784 A CN110803784 A CN 110803784A CN 201810887141 A CN201810887141 A CN 201810887141A CN 110803784 A CN110803784 A CN 110803784A
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water
corrosion
ferric
salt
scale inhibitor
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郦和生
楼琼慧
谢文州
秦会敏
王洪英
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
    • C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
    • C02F5/12—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances containing nitrogen
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F14/00—Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes
    • C23F14/02—Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes by chemical means
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/08—Corrosion inhibition

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Water Supply & Treatment (AREA)
  • Environmental & Geological Engineering (AREA)
  • Hydrology & Water Resources (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Abstract

The invention relates to the field of corrosion of circulating cooling water containing sulfur, and discloses a composite corrosion and scale inhibitor containing water-soluble silicate, application thereof and a method for inhibiting corrosion of circulating cooling water containing sulfur. The composite corrosion and scale inhibitor contains hydrolyzed polymaleic anhydride, zinc salt, silicate and sulfonate copolymer, wherein the weight ratio of the hydrolyzed polymaleic anhydride to the zinc salt to the silicate to the sulfonate copolymer is 1:0.2-0.4:3.5-5.5:1.2-1.8, the weight of the zinc salt is calculated by zinc ions, and the weight of the silicate is calculated by silicon dioxide. According to the method provided by the invention, the composite corrosion and scale inhibitor and the compound of the trivalent iron salt and the nitrilotriacetic acid are used in a matching way, so that a better corrosion and scale inhibiting effect can be obtained. The method can effectively inhibit the corrosion of sulfide in the sulfur-containing circulating cooling water to the water cooling equipment without using a large amount of medicaments and fresh water, and can effectively reduce the operation cost.

Description

Composite corrosion and scale inhibitor containing water-soluble silicate, application thereof and method for inhibiting corrosion of circulating cooling water containing sulfur
Technical Field
The invention relates to the field of corrosion of circulating cooling water containing sulfur, in particular to a composite corrosion and scale inhibitor containing water-soluble silicate, application thereof and a method for inhibiting corrosion of circulating cooling water containing sulfur.
Background
In recent years, processing of highly corrosive crude oil containing high sulfur content in an oil refinery causes corrosion perforation of equipment, and a phenomenon of leakage of materials into circulating water occurs. Sulfides in crude oil can be divided into inorganic sulfur and organic sulfur, wherein the organic sulfur comprises mercaptan, thioether, disulfide, polysulfide, cyclic sulfide, thiophene and the like; the inorganic sulfur mainly comprises elemental sulfur and H2And S. These substances can directly corrode metals, and if corrosion perforation causes leakage of materials, the leaked materials can enter the circulating cooling water, causing serious deterioration of the quality of the circulating cooling water. Especially H2S gas can form sulfur ions (S) after entering the circulating cooling water2-) The sulfur ions not only can act with the surface of the metal, but also can act with a corrosion and scale inhibitor or a bactericide in the circulating cooling water, so that a series of problems of serious corrosion or standard exceeding of microorganisms and the like are caused to a water body. These problems will aggravate the corrosion of the equipment for cooling and exchanging the circulating cooling water, and further aggravate the leakage degree of the material, and form a vicious circle. At present, the treatment measures of the oil refinery for the circulating cooling water containing the sulfide ions are mainly two types: the first is to add a large amount of corrosion and scale inhibitor to increase the corrosion and scale inhibition effect; the second is bulk blowdown and fresh water make-up to reduce the sulphide concentration in the recycle water. Although the measures have certain effect, the dosage of the medicament is large, the fresh water consumption and the sewage discharge are greatly increased, and the operation cost of the circulating water system is increased.
CN1958848A discloses a method for inhibiting corrosion of cooling water containing sulfur circulation, which comprises controlling the alkalinity of sulfur-containing circulation water calculated by calcium carbonate to be 250-350mg/L, then adding composite corrosion inhibitor into the circulating cooling water, the adding amount is 5-40 times of the mass concentration of the discharged sulfur ions in the circulating water, the composite corrosion inhibitor contains 2-24 wt% of organic corrosion inhibitor selected from one or two or more of hydroxyethylidene diphosphonic acid, hydroxyphosphinoacetic acid, amino trimethylene phosphonic acid, ethylene diamine tetramethylene phosphonic acid, 2-phosphino-1, 2, 4-tricarboxylic acid-butane and potassium salt, sodium salt, polyhydric alcohol phosphate and polyether alcohol amine phosphate, the method can control the corrosion rate to be below 0.075mm/a by matching with the operation under the condition of not changing the original medicament adding of the circulating water field. The composite corrosion inhibitor is an organic phosphonic acid medicament, the corrosion and scale inhibition formula on the market at present is mainly an organic phosphine formula, and the composite corrosion inhibitor is added with the organic phosphine medicament under the condition of adding the original medicament, which aims to achieve the purpose of reducing corrosion by improving the adding concentration of the corrosion and scale inhibitor.
CN103420493A discloses a method for treating circulating cooling water containing sulfur ions, which comprises: mixing and contacting circulating cooling water containing sulfur ions with a precipitator and a corrosion and scale inhibitor, wherein the precipitator can form precipitates with the sulfur ions, the corrosion and scale inhibitor is at least one selected from vanadate, organic phosphonic acid, organic polymer and water-soluble zinc salt, and the precipitator is copper sulfate. The method adopts copper salt as a precipitator, has certain effect, but promotes carbon steel corrosion when copper ions in the circulating water exceed 0.1mg/L, and in practical application, the concentration of sulfur ions leaked from the circulating water is changed, and the adding amount of the copper ions is difficult to accurately control.
Therefore, a composite corrosion and scale inhibitor and a novel method for inhibiting the corrosion of circulating cooling water containing sulfur are needed at present, and the corrosion of sulfides on a water cooler can be effectively inhibited without a large amount of medicaments or a large amount of pollution discharge and fresh water supplement.
Disclosure of Invention
The invention aims to solve the problems of high operating cost caused by large consumption of corrosion and scale inhibitor, large fresh water consumption and large discharge capacity in the process of inhibiting the corrosion of the circulating cooling water containing sulfur in the prior art, and provides a novel composite corrosion and scale inhibitor and a method for inhibiting the corrosion of the circulating cooling water containing sulfur.
In order to achieve the above object, the present invention provides a composite corrosion and scale inhibitor containing water-soluble silicate, which comprises hydrolyzed polymaleic anhydride (HPMA), a water-soluble zinc salt, a water-soluble silicate and a sulfonate copolymer, wherein the weight ratio of the HPMA, the water-soluble zinc salt, the water-soluble silicate and the sulfonate copolymer is 1:0.2-0.4:3.5-5.5:1.2-1.8, wherein the weight of the water-soluble zinc salt is calculated as zinc ions, and the weight of the water-soluble silicate is calculated as silica.
The invention also provides an application of the composite corrosion and scale inhibitor in inhibiting the corrosion of circulating cooling water containing sulfur.
In a third aspect, the present invention provides a method for inhibiting corrosion of circulating cooling water containing sulfur, the method comprising:
(1) adding the composite corrosion and scale inhibitor;
(2) and adding a compound of a trivalent ferric salt and nitrilotriacetic acid, wherein the weight ratio of the trivalent ferric salt to the nitrilotriacetic acid is 1:3-6, the weight of the trivalent ferric salt is calculated by trivalent ferric ions, and the adding amount of the compound of the trivalent ferric salt and the nitrilotriacetic acid ensures that the concentration of the trivalent ferric ions in the sulfur-containing circulating cooling water is 1.5-2 mg/L.
Through the technical scheme, the corrosion of the sulfur-containing circulating cooling water to the water cooling equipment can be effectively inhibited under the condition of not using a large amount of medicaments and fresh water, and the operation cost is reduced.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides a composite corrosion and scale inhibitor containing water-soluble silicate, which contains hydrolyzed polymaleic anhydride (HPMA), water-soluble zinc salt, water-soluble silicate and sulfonate copolymer, wherein the weight ratio of the HPMA to the water-soluble zinc salt to the water-soluble silicate to the sulfonate copolymer is 1:0.2-0.4:3.5-5.5:1.2-1.8, the weight of the water-soluble zinc salt is calculated by zinc ions, and the weight of the water-soluble silicate is calculated by silicon dioxide. According to a preferred embodiment of the present invention, the composite corrosion and scale inhibitor of the present invention is free of phosphorus.
According to the present invention, the HPMA, the water-soluble zinc salt and the water-soluble silicate are all commercially available. Preferably, the weight average molecular weight of the HPMA is 600-800.
According to the invention, the water-soluble zinc salt is an inorganic salt which is soluble in water and provides zinc ions. Preferably, the water soluble zinc salt is selected from zinc sulphate and/or zinc chloride.
According to the invention, the water-soluble silicate may be an orthosilicate or a metasilicate dissolved in water. Preferably, the silicate is selected from at least one of sodium orthosilicate, potassium orthosilicate, sodium metasilicate, and potassium metasilicate.
According to the present invention, the sulfonate copolymer is commercially available. Preferably, the sulfonate copolymer comprises a structural unit provided by acrylic acid, a structural unit provided by 2-methyl-2 '-acrylamidopropanesulfonic acid, and optionally a structural unit provided by other monomers, the other monomers being at least one of acrylamide, methyl acrylate, and maleic acid, the molar percentage of the structural unit provided by the 2-methyl-2' -acrylamidopropanesulfonic acid is 10 to 30% based on the total amount of the sulfonate copolymer, and the sulfonate copolymer has an ultimate viscosity of 0.065 to 0.085 dL/g.
More preferably, the sulfonate copolymer is selected from at least one of a copolymer of acrylic acid and 2-methyl-2 '-acrylamidopropanesulfonic acid, a copolymer of acrylic acid, acrylamide and 2-methyl-2' -acrylamidopropanesulfonic acid, a copolymer of acrylic acid, hydroxypropyl acrylate and 2-methyl-2 '-acrylamidopropanesulfonic acid, and a copolymer of acrylic acid, maleic acid and 2-methyl-2' -acrylamidopropanesulfonic acid.
In order to make the composite corrosion and scale inhibitor better suitable for the circulating cooling water containing sulfur, preferably, the composite corrosion and scale inhibitor contains a composite of independent trivalent ferric salt and nitrilotriacetic acid, wherein the weight ratio of the trivalent ferric salt to the nitrilotriacetic acid in the composite is 1:3-6, wherein the weight of the trivalent ferric salt is calculated by trivalent ferric ions.
The nitrilotriacetic acid in the compound can be chelated with iron ions, so that the iron ions are not easy to deposit.
According to the present invention, the ferric salt is an inorganic salt that is soluble in water to provide ferric ions, both of which are commercially available as nitrilotriacetic acid. Preferably, the ferric salt is selected from at least one of ferric chloride, ferric nitrate and ferric sulfate.
According to a preferred embodiment of the invention, the composite corrosion and scale inhibitor consists of the components.
The invention provides an application of the composite corrosion and scale inhibitor in inhibiting corrosion of circulating cooling water containing sulfur.
After entering the circulating cooling water, the sulfide exists in the form of sulfide ions. According to the invention, preferably, the content of sulfur ions in the circulating cooling water containing sulfur is 0.5-2 mg/L.
According to the invention, the adding concentration of the composite corrosion and scale inhibitor can be properly adjusted according to the content of sulfur ions in the sulfur-containing circulating cooling water. Preferably, the total adding concentration of the hydrolyzed polymaleic anhydride, the water-soluble zinc salt, the water-soluble silicate and the sulfonate copolymer is 45-60mg/L of water.
In a third aspect, the present invention provides a method for inhibiting corrosion of circulating cooling water containing sulfur, the method comprising:
(1) adding the composite corrosion and scale inhibitor;
(2) adding a compound of trivalent ferric salt and nitrilotriacetic acid, wherein the weight ratio of the trivalent ferric salt to the nitrilotriacetic acid in the compound is 1:3-6, and the weight of the trivalent ferric salt is calculated by trivalent ferric ions; the compound of the ferric salt and the nitrilotriacetic acid is added in an amount to ensure that the concentration of the ferric ions in the circulating cooling water containing sulfur is 1.5-2 mg/L.
According to the present invention, the ferric salt is an inorganic salt that is soluble in water to provide ferric ions, both of which are commercially available as nitrilotriacetic acid. Preferably, the ferric salt is selected from at least one of ferric chloride, ferric nitrate and ferric sulfate.
According to the invention, the compound of the trivalent ferric salt and the nitrilotriacetic acid is added, so that on one hand, the sulfur ions in the sulfur-containing circulating cooling water can be reduced, and on the other hand, the nitrilotriacetic acid can stabilize the iron ions in the sulfur-containing circulating cooling water, so that the iron ions are not easy to deposit on the surface of carbon steel to accelerate corrosion.
According to the invention, the adding concentration of the composite corrosion and scale inhibitor can be properly adjusted according to the content of sulfur ions in the sulfur-containing circulating cooling water. Preferably, the total adding concentration of the hydrolyzed polymaleic anhydride, the water-soluble zinc salt, the water-soluble silicate and the sulfonate copolymer is 45-60mg/L of water.
According to the invention, the method can be applied to circulating cooling water with different sulfur ion contents. Preferably, the content of sulfur ions in the circulating cooling water containing sulfur is 0.5-2mg/L, Ca2+The content of (1) is 200-500mg/L, the total alkalinity is 200-500mg/L, and Cl-The content of (A) is 20-700mg/L, SO4 2-The content of (b) is 50-500mg/L, the conductivity is 500-3000 mu s/cm, and the pH is 7-8.5.
The present invention will be described in detail below by way of examples. The starting materials used are all commercially available unless otherwise specified.
In the following examples, the actual sulfur leakage was simulated by adding sodium sulfide to the test raw water, and the quality of the test raw water is shown in table 1.
TABLE 1
Ca2+ Total alkalinity Cl- SO4 2- Electrical conductivity of pH
Test raw Water 1 430 475 436 420 2360 8.2
Test raw Water 2 253 214 28 85 568 7.5
Note: pH is nothing, conductivity is mus/cm, the rest is mg/L, Ca2+CaCO for total alkalinity3The same applies below.
In Table 1, Ca2+According to the national standard GB/T6910-; the total alkalinity is according to the national standard GB/T15451-2006 Industrial cycleMeasuring the alkalinity of cooling water, total alkali and phenolphthalein; cl-Measured according to the standard GB/T15453-2008; SO (SO)4 2-Determined according to standard GB/T14642-; the conductivity is determined according to the standard GB/T6908-2008; the pH value was determined according to the standard GB/T6920-1986.
The rotary coupon corrosion test method comprises the following steps:
will 20#Fixing the carbon steel test piece on a coupon instrument, placing the test piece in test water, keeping the constant temperature at 45 +/-1 ℃, keeping the rotating speed at 75r/min for 72 hours, recording the weight of the test piece before and after the test, and calculating the average corrosion rate.
The average corrosion rate is calculated by the formula:
F＝(C×△W)/(A×T×ρ)
c: the constants were calculated, in mm/a, such that C is 8.76 × 107；
△ W, corrosion weight loss (g) of the test piece;
a: area of test piece (cm)2)；
T: corrosion test time (h);
ρ: density of test piece Material (kg/m)3)。
The test method for calcium carbonate scale resistance comprises the following steps:
adding test raw water into a volumetric flask, adding sodium sulfide, a composite corrosion and scale inhibitor and other substances according to the embodiment and the comparative example, standing for 10 hours in a constant-temperature water bath at the temperature of 80 +/-1 ℃ after constant volume, sampling and analyzing the residual Ca in the water after cooling2+And simultaneously making blank samples, and calculating the scale inhibition rate.
Scale inhibition rate ═ C-C0)/(C1－C0)×100％
C: ca after test of test solution added with water treatment agent2+Concentration of (g/L);
C0: ca after blank test without water treatment agent2+Concentration of (g/L);
C1: ca in prepared test solution before test2+(iii) concentration (mg/L).
Example 1
Test water was obtained by adding sodium sulfide to test raw water 1 so that the concentration of sulfide ions was 1 mg/L. Adding 50mg/L of composite corrosion and scale inhibitor, wherein the composite corrosion and scale inhibitor comprises the following components: HPMA (weight average molecular weight of 700, available from santai and water treatment technologies co., ltd.; hereinafter) zinc sulfate (calculated as zinc ion), sodium orthosilicate (calculated as silica), a copolymer of acrylic acid and 2-methyl-2' -acrylamidopropanesulfonic acid (70 and 30 mole percent of the two monomers, respectively, and an ultimate viscosity of 0.071dL/g, available from santai and water treatment technologies co., ltd.) -1: 0.3:4:1.5 (weight ratio); then, a complex of ferric chloride and nitrilotriacetic acid was added, wherein the ferric chloride (in terms of ferric ions) and the nitrilotriacetic acid were 1:4.5 (by weight), so that the concentration of ferric ions in the water was 1.6 mg/L. A rotary coupon corrosion test and a calcium carbonate scale resistance test are carried out, the corrosion rate is 0.042mm/a, and the scale inhibition rate is 98.5%.
Example 2
Test water was obtained by adding sodium sulfide to test raw water 1 so that the concentration of sulfide ions was 1 mg/L. 58mg/L of composite corrosion and scale inhibitor is added, and the composite corrosion and scale inhibitor comprises the following components: zinc sulfate (as zinc ion), potassium orthosilicate (as silica), a copolymer of acrylic acid, acrylamide, and 2-methyl-2' -acrylamidopropanesulfonic acid (70, 15, and 15 mole percent of each of the three monomers, 0.068dL/g ultimate viscosity, available from Shandongtai and Water treatment technologies, Inc.) 1:0.22:3.6:1.7 (by weight); then, a complex of ferric sulfate and nitrilotriacetic acid was added, wherein the ferric sulfate (in terms of ferric ions) and nitrilotriacetic acid were 1:3.2 (by weight), so that the concentration of ferric ions in water was 1.7 mg/L. A rotary coupon corrosion test and a calcium carbonate scale resistance test are carried out, the corrosion rate is 0.044mm/a, and the scale inhibition rate is 98.2%.
Example 3
Test water was obtained by adding sodium sulfide to test raw water 1 so that the concentration of sulfide ions was 1 mg/L. Adding 47mg/L of composite corrosion and scale inhibitor, wherein the composite corrosion and scale inhibitor comprises the following components: zinc sulfate (as zinc ions), sodium metasilicate (as silica), a copolymer of acrylic acid, hydroxypropyl acrylate, and 2-methyl-2' -acrylamidopropanesulfonic acid (70, 15, and 15 mole percent of each of the three monomers, respectively, and an ultimate viscosity of 0.070dL/g, available from Shandongtai and Water treatment technologies, Inc.) 1:0.38:5.4:1.3 (by weight); then, a complex of ferric nitrate and nitrilotriacetic acid was added, wherein the ferric nitrate (in terms of ferric ions) and nitrilotriacetic acid were 1:5.8 (weight ratio) to make the concentration of ferric ions in water 1.8 mg/L. A rotary coupon corrosion test and a calcium carbonate scale resistance test are carried out, the corrosion rate is 0.051mm/a, and the scale inhibition rate is 98.4%.
Example 4
Test water was obtained by adding sodium sulfide to test raw water 1 so that the concentration of sulfide ions was 1 mg/L. Adding 55mg/L of composite corrosion and scale inhibitor, wherein the composite corrosion and scale inhibitor comprises the following components: zinc chloride (as zinc ions), potassium metasilicate (as silica), and a copolymer of acrylic acid, maleic acid, and 2-methyl-2' -acrylamidopropanesulfonic acid (70, 15, and 15 mole percent of each of the three monomers, respectively, and an ultimate viscosity of 0.080dL/g, available from shandongtai and water processing technologies, inc.) in a weight ratio of 1:0.35:5: 1.6; then, a complex of ferric chloride and nitrilotriacetic acid was added, wherein the ferric chloride (in terms of ferric ions) and nitrilotriacetic acid were 1:5 (weight ratio), so that the concentration of ferric ions in water was 1.9 mg/L. The corrosion test of the rotary hanging piece and the test of calcium carbonate scale resistance are carried out, the corrosion rate is 0.045mm/a, and the scale inhibition rate is 98.0 percent.
Example 5
The test was conducted in accordance with the method of example 1 except that the concentration of sulfur ions was 0.5mg/L, the corrosion rate was measured to be 0.030mm/a, and the scale inhibition rate was 98.8%.
Example 6
The test was conducted in accordance with the method of example 1 except that the concentration of sulfur ion was 2mg/L, the corrosion rate was measured to be 0.055mm/a, and the scale inhibition rate was 97.2%.
Example 7
A test was conducted in the same manner as in example 1 except that the copolymer of acrylic acid and 2-methyl-2' -acrylamidopropanesulfonic acid was replaced with a copolymer of acrylic acid and styrenesulfonic acid (the molar percentages of the two monomers were 70% and 30%, respectively, and the limiting viscosity was 0.080dL/g), and it was found that the corrosion rate was 0.071mm/a and the scale inhibition rate was 97.0%.
Example 8
The test was conducted in the same manner as in example 1 except that the test raw water 1 was replaced with the test raw water 2 to measure the corrosion rate of 0.057mm/a and the scale inhibition rate of 99.4%.
Comparative example 1
The test was carried out according to the method of example 1, except that the composition of the composite corrosion and scale inhibitor used was: zinc sulfate (as zinc ion), sodium orthosilicate (as silica), a copolymer of acrylic acid and 2-methyl-2' -acrylamidopropanesulfonic acid (weight ratio) 1:0.2:6:1, corrosion rate was 0.142mm/a, and scale inhibition was 87.9%.
Comparative example 2
The test was conducted in accordance with the procedure of example 1 except that ferric chloride (in terms of ferric ion) and nitrilotriacetic acid were 1:2 (weight ratio), the corrosion rate was measured to be 0.145mm/a and the scale inhibition rate was 97.6%.
Comparative example 3
The test was carried out in the same manner as in example 1 except that a complex of ferric chloride and nitrilotriacetic acid was added so that the concentration of ferric ions in water was 1mg/L, and it was found that the corrosion rate was 0.104mm/a and the scale inhibition rate was 98.2%.
Comparative example 4
The test was carried out in the same manner as in example 1 except that the composite corrosion and scale inhibitor used contained no HPMA, and it was found that the corrosion rate was 0.132mm/a and the scale inhibition rate was 73.5%.
Comparative example 5
The test was conducted in accordance with the procedure of example 1 except that the HPMA in the composite corrosion and scale inhibitor was replaced with polyaspartic acid (weight average molecular weight of 3000, available from Shandongtai and Water treatment science and technology Co., Ltd.), and it was found that the corrosion rate was 0.082mm/a and the scale inhibition rate was 95.8%.
Comparative example 6
The test was carried out in the same manner as in example 1 except that the composite corrosion and scale inhibitor used was not a copolymer of acrylic acid and 2-methyl-2' -acrylamidopropanesulfonic acid, and it was found that the corrosion rate was 0.308mm/a and the scale inhibition rate was 78.2%.
Comparative example 7
The test was carried out in the same manner as in example 1 except that the composite corrosion and scale inhibitor used contained no water-soluble silicate, and it was found that the corrosion rate was 0.288mm/a and the scale inhibition rate was 98.8%.
Comparative example 8
The test was conducted in accordance with the procedure of example 1 except that the composite corrosion and scale inhibitor used had zinc sulfate replaced with copper sulfate (in mass terms of copper ions), and found that the corrosion rate was 1.375mm/a and the scale inhibition rate was 97.5%.
It can be seen from the above examples and comparative examples that the water-soluble silicate-containing composite corrosion and scale inhibitor provided by the invention is compounded by hydrolyzed polymaleic anhydride, zinc salt, silicate and sulfonate copolymer, and the weight ratio is limited to 1:0.2-0.4:3.5-5.5:1.2-1.8, so that the water-soluble silicate-containing composite corrosion and scale inhibitor can play a synergistic role and has good corrosion and scale inhibition effects. When the compound is used in combination with a ferric salt and nitrilotriacetic acid (the weight ratio of ferric ions to nitrilotriacetic acid is 1:3-6), the effect of better inhibiting the corrosion of the water cooling equipment by the sulfur-containing circulating cooling water can be realized when the concentration of the ferric ions is maintained at 1.5-2 mg/L.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (10)

1. The composite corrosion and scale inhibitor containing the water-soluble silicate is characterized by comprising hydrolyzed polymaleic anhydride, water-soluble zinc salt, water-soluble silicate and sulfonate copolymer, wherein the weight ratio of the hydrolyzed polymaleic anhydride to the water-soluble zinc salt to the water-soluble silicate to the sulfonate copolymer is 1:0.2-0.4:3.5-5.5:1.2-1.8, the weight of the water-soluble zinc salt is calculated by zinc ions, and the weight of the water-soluble silicate is calculated by silicon dioxide.
2. The composite corrosion and scale inhibitor according to claim 1, wherein the water soluble zinc salt is selected from zinc sulfate and/or zinc chloride;
preferably, the water-soluble silicate is selected from at least one of sodium orthosilicate, potassium orthosilicate, sodium metasilicate, and potassium metasilicate;
preferably, the hydrolyzed polymaleic anhydride has a weight average molecular weight of 600-800.
3. The composite corrosion and scale inhibitor according to claim 1, wherein the sulfonate copolymer comprises structural units provided by acrylic acid, structural units provided by 2-methyl-2 '-acrylamidopropanesulfonic acid, and optionally structural units provided by other monomers, the other monomers being at least one of acrylamide, methyl acrylate, and maleic acid, the mole percentage of the structural units provided by the 2-methyl-2' -acrylamidopropanesulfonic acid based on the total amount of the sulfonate copolymer being from 10 to 30%, the sulfonate copolymer having an ultimate viscosity of from 0.065 to 0.085 dL/g;
preferably, the sulfonate copolymer is selected from at least one of a copolymer of acrylic acid and 2-methyl-2 '-acrylamidopropanesulfonic acid, a copolymer of acrylic acid, acrylamide and 2-methyl-2' -acrylamidopropanesulfonic acid, a copolymer of acrylic acid, hydroxypropyl acrylate and 2-methyl-2 '-acrylamidopropanesulfonic acid, and a copolymer of acrylic acid, maleic acid and 2-methyl-2' -acrylamidopropanesulfonic acid.
4. The composite corrosion and scale inhibitor according to claim 1, further comprising a separately present composite of a trivalent iron salt and nitrilotriacetic acid, wherein the weight ratio of the trivalent iron salt to the nitrilotriacetic acid in the composite is 1:3-6, wherein the weight of the trivalent iron salt is calculated by trivalent iron ions.
5. The composite corrosion and scale inhibitor according to claim 4, wherein the ferric salt is selected from at least one of ferric chloride, ferric nitrate and ferric sulfate.
6. The use of the composite corrosion and scale inhibitor according to any one of claims 1 to 5 for inhibiting the corrosion of circulating cooling water containing sulfur, preferably, the content of sulfur ions in the circulating cooling water containing sulfur is 0.5 to 2 mg/L.
7. The use of claim 6, wherein the hydrolyzed polymaleic anhydride, the water-soluble zinc salt, the water-soluble silicate and the sulfonate copolymer are added in a total concentration of 45-60 mg/L.
8. A method for inhibiting corrosion in circulating cooling water containing sulfur, the method comprising:
(1) adding the composite corrosion and scale inhibitor of any one of claims 1-3;
(2) adding a compound of trivalent ferric salt and nitrilotriacetic acid, wherein the weight ratio of the trivalent ferric salt to the nitrilotriacetic acid in the compound is 1:3-6, and the weight of the trivalent ferric salt is calculated by trivalent ferric ions; the adding amount of the compound of the ferric iron salt and the nitrilotriacetic acid ensures that the concentration of the ferric iron ions in the circulating cooling water containing sulfur is 1.5-2 mg/L;
preferably, the ferric salt is selected from at least one of ferric chloride, ferric nitrate and ferric sulfate.
9. The method according to claim 8, wherein the hydrolyzed polymaleic anhydride, the water-soluble zinc salt, the water-soluble silicate and the sulfonate copolymer are added in a total concentration of 45-60 mg/L.
10. The method of claim 8 or 9, wherein the content of the sulfur ions in the circulating cooling water containing sulfur is 0.5-2 mg/L.
CN201810887141.8A 2018-08-06 2018-08-06 Composite corrosion and scale inhibitor containing water-soluble silicate, application thereof and method for inhibiting corrosion of circulating cooling water containing sulfur Pending CN110803784A (en)

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CN103572297A (en) * 2012-07-26 2014-02-12 中国石油化工股份有限公司 Method for treating recirculated cooling water containing sulfur
CN104556420A (en) * 2013-10-12 2015-04-29 中国石油化工股份有限公司 Non-phosphorus composite corrosion and scale inhibitor and preparation method thereof, as well as corrosion and scale inhibition method of circulating cooling water
CN105776589A (en) * 2016-04-25 2016-07-20 苏州能华节能环保科技有限公司 Non-phosphorus type environment-friendly slow-release scaling inhibitor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3897209A (en) * 1971-12-10 1975-07-29 Ciba Geigy Corp Corrosion inhibitors for metals in aqueous systems
CN87107003A (en) * 1986-10-17 1988-04-27 株式会社片山化学工业研究所 Anticorrosion treatment method for soft water boiler
FR2659316A1 (en) * 1990-03-10 1991-09-13 Ciba Geigy Ag Scale-preventing composition and process for treating water systems
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