Composition with scale and corrosion inhibition functions and application thereof in water treatment

Abstract

The invention relates to the field of water treatment agents, and discloses a composition with scale inhibition and corrosion inhibition functions, the composition comprises a first component, a second component, a third component, a fourth component and an optional Schiff base compound; the first component is selected from at least one of a C2-C6 alcohol amine compound, a C4-C8 cyclic amine compound, a nitrogen-containing heterocyclic compound and gluconate; the second component is selected from at least one of a benzotriazole compound, a benzothiazole compound and a thiourea compound; the third component is an inorganic metal salt; the fourth component is selected from at least one of a sodium acetate compound, sodium polyacrylate, sodium polymaleate and polyepoxysuccinic acid. The composition has relatively strong scale inhibition and scale dissolving effects on a high-hardness and high-alkalinity circulating water system, has long-term corrosion inhibition on metals, and reduces the water supplementing and changing times of the circulating water system.

Description

Technical Field

[0001] The present invention relates to the field of water treatment agents, and particularly relates to a composition having scale inhibition and corrosion inhibition functions and its application in water treatment. Background Art

[0002] When cooling water is used, it circulates and concentrates continuously, and the mineral content in the water will also increase continuously, thus causing scale formation and corrosion in equipment pipelines. The presence of dirt will not only affect the heat transfer efficiency but also cause under-scale corrosion. Therefore, it is very important to use scale and corrosion inhibitors in circulating water.

[0003] Currently, in the process of industrial circulating cooling water treatment, most methods use the addition of chemical agents to control the formation of dirt. Generally, chemical agents that can prevent the formation of water scale and dirt or inhibit their deposition and growth are collectively called scale inhibitors. The commonly used forms of scale inhibitors in industry are mainly scale and corrosion inhibitors and scale dispersants.

[0004] Scale dispersants are mainly water-soluble polymers with medium and low molecular weights, including two categories: homopolymers and copolymers. Among them, homopolymers include polyacrylic acid and its sodium salts, hydrolyzed polymaleic anhydride, etc. There are many varieties of copolymers, mainly binary or ternary copolymers of acrylic acid series and maleic acid series. Scale and corrosion inhibitors mostly use phosphorus-based formulations, and the most used among them is organic polyphosphoric acid. Although a small amount of non-phosphorus-based scale and corrosion inhibitors have been developed in the current field, the research on non-phosphorus-based scale and corrosion inhibitors for high-hardness closed-loop circulating water systems is still relatively less. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art, and provide a composition having scale inhibition and corrosion inhibition functions and its application in water treatment. This composition has a strong scale inhibition and scale dissolution effect on circulating water systems with high hardness and high alkalinity, has long-term corrosion inhibition on metals, and reduces the number of times of makeup water and water replacement in the circulating water system.

[0006] To achieve the above purpose, in the first aspect of the present invention, a composition having scale inhibition and corrosion inhibition functions is provided. The composition includes a first component, a second component, a third component, a fourth component, and an optional Schiff base compound;

[0007] The first component is selected from at least one of C2-C6 alkanolamine compounds, C4-C8 cycloamine compounds, nitrogen-containing heterocyclic compounds, and gluconates;

[0008] The second component is selected from at least one of benzotriazole compounds, benzothiazole compounds, and thiourea compounds;

[0009] The third component is an inorganic metal salt;

[0010] The fourth component is selected from at least one of sodium acetate compounds, sodium polyacrylate, sodium polymaleate, and polyepoxysuccinic acid.

[0011] The second aspect of the present invention provides a method for treating circulating water, and the treatment method includes:

[0012] Contacting the composition as described above with the circulating water.

[0013] The third aspect of the present invention provides the application of the composition as described above and / or the treatment method as described above in a circulating water system.

[0014] Through the above technical solutions, the present invention has at least the following beneficial effects:

[0015] (1) The composition provided by the present invention has a strong scale inhibition and scale dissolution effect on circulating water systems with high hardness and high alkalinity, has long-term corrosion inhibition on metals, and reduces the number of times of makeup water and water replacement in the circulating water system.

[0016] (2) The water treatment method provided by the present invention can specifically treat circulating water with a total content of hardness and alkalinity above 100 ppm, and can also exert good corrosion inhibition and pH buffering effects in weakly acidic water quality. Description of the Drawings

[0017] Figure 1 It is a graph of the corrosion rate experimental results of Test Example 2. Detailed Embodiments

[0018] The endpoints and any values within the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0019] The first aspect of the present invention provides a composition having scale inhibition and corrosion inhibition functions, and the composition includes a first component, a second component, a third component, a fourth component, and an optional Schiff base compound;

[0020] The first component is selected from at least one of C2-C6 alkanolamine compounds, C4-C8 cycloamine compounds, nitrogen-containing heterocyclic compounds, and gluconates;

[0021] The second component is selected from at least one of benzotriazole compounds, benzothiazole compounds, and thiourea compounds;

[0022] The third component is an inorganic metal salt;

[0023] The fourth component is selected from at least one of sodium acetate compounds, sodium polyacrylate, sodium polymaleate, and polyepoxysuccinic acid.

[0024] In the present invention, the above composition has excellent scale inhibition and scale dissolution effects when used in a circulating water system, and can play a corrosion inhibition role for a long time.

[0025] In the present invention, the molecular weights of the sodium polyacrylate, sodium polymaleate, and polyepoxysuccinic acid can be conventional selections in the art.

[0026] In the present invention, preferably, the number-average molecular weight of the sodium polyacrylate is 1000 - 3000, preferably 2000 - 3000.

[0027] Preferably, the number-average molecular weight of the sodium polymaleate is 300 - 1000, preferably 400 - 800.

[0028] Preferably, the number-average molecular weight of the polyepoxysuccinic acid is 800 - 1700, preferably 1000 - 1500.

[0029] In the present invention, adding the Schiff base compound to the composition can improve the corrosion inhibition effect of the composition.

[0030] According to the present invention, preferably, the C2 - C6 alkanolamine compounds include at least one of monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, and isobutanolamine.

[0031] According to the present invention, preferably, the C4 - C8 cyclic amine compounds include at least one of cyclopentylamine, cyclohexylamine, and cycloheptylamine.

[0032] According to the present invention, preferably, the nitrogen-containing heterocyclic compounds include at least one of oleic acid imidazoline, methylimidazole, and 3 - amino - 1,2,4 - triazole.

[0033] According to the present invention, preferably, the gluconates include at least one of sodium gluconate, potassium gluconate, and zinc gluconate.

[0034] According to the present invention, preferably, the benzotriazole compounds include at least one of benzotriazole, methylbenzotriazole, and hydroxybenzotriazole.

[0035] According to the present invention, preferably, the benzothiazole compounds include at least one of mercaptobenzothiazole, sodium mercaptobenzothiazole, and hydroxybenzothiazole.

[0036] According to the present invention, preferably, the thiourea compounds include at least one of thiourea, semicarbazide hydrochloride, thiosemicarbazide, and amidinothiourea.

[0037] According to the present invention, preferably, the inorganic metal salt includes at least one of cerium nitrate, rhenium nitrate, sodium nitrate, sodium nitrite, sodium molybdate, and sodium tungstate.

[0038] According to the present invention, preferably, the sodium acetate-based compound includes at least one of tetrasodium glutamate diacetate, tetrasodium ethylenediaminetetraacetate, and pentasodium diethylenetriaminepentaacetate.

[0039] In some preferred embodiments of the present invention, the composition includes a first component, a second component, a third component, a fourth component, and a Schiff base compound;

[0040] The first component is monoethanolamine, sodium gluconate, and optionally cyclohexylamine. Preferably, the weight ratio of monoethanolamine to sodium gluconate is (1.25 - 3):1;

[0041] The second component is benzotriazole and thiourea. Preferably, the weight ratio of the two is (1 - 1.2):1;

[0042] The third component is sodium tungstate and sodium nitrate. Preferably, the weight ratio of the two is (1 - 1.2):1;

[0043] The fourth component is sodium polymaleate, pentasodium diethylenetriaminepentaacetate, and polysuccinic acid. Preferably, the weight ratio of the three is (1 - 1.5):(1 - 1.5):1.

[0044] In the present invention, when the composition includes the above components, its corrosion inhibition effect and scale inhibition effect are significantly improved.

[0045] According to the present invention, preferably, the weight ratio of the first component, the second component, the third component, the fourth component, and the Schiff base compound is 1:0.05 - 0.20:0.08 - 0.25:0.2 - 0.4:0 - 0.008.

[0046] In the present invention, when the weight ratio of each component in the composition is within the above range, it can effectively prevent scale formation in the circulating water system and reduce the metal corrosion rate in the circulating water system.

[0047] Further preferably, the weight ratio of the first component, the second component, the third component, the fourth component, and the Schiff base compound is 1:0.05 - 0.15:0.10 - 0.15:0.2 - 0.3:0.005 - 0.008.

[0048] In the present invention, for the convenience of use, the composition further includes a solvent (usually water), and the amount of water used is 3 - 5 g relative to each gram of the first component.

[0049] According to the present invention, preferably, the composition does not contain phosphorus elements.

[0050] In the present invention, the composition does not contain phosphorus element, which is more beneficial to preventing the growth of algae in water and can reduce the post-treatment process during the discharge of circulating water.

[0051] According to the present invention, preferably, the Schiff base compound has the structure shown in formula (1),

[0052]

[0053] In the present invention, the Schiff base compound can be obtained by commercial purchase or synthesized by conventional methods in the field. For example, it can be synthesized by the following method: 3,5-dihydroxy salicylaldehyde and p-phenylenediamine are mixed in a molar ratio of 1.5 - 2.5:1, dissolved in a solvent, and then 1 - 5 wt‰ of formic acid based on the mass of p-phenylenediamine is added, and the reaction is carried out by heating. Preferably, after the reaction is completed, it is purified by column chromatography (stationary phase: 400-mesh silica gel, mobile phase: dichloromethane:methanol = 10:1).

[0054] In the second aspect of the present invention, a method for treating circulating water is provided, and the treatment method includes:

[0055] Contacting the composition as described above with the circulating water.

[0056] In the present invention, the manner of the contact is not particularly limited and can be a conventional operation in the field. The composition can be directly contacted with the circulating water, or can be dissolved in various solvents by any means and then contacted with the circulating water.

[0057] In the present invention, the composition can be used for various types of circulating water in the field. Preferably, the composition can be used for circulating water with high hardness and high alkalinity.

[0058] According to the present invention, preferably, the total content of hardness and alkalinity in the circulating water is 100 - 600 ppm in terms of CaCO3;

[0059] In the present invention, the sum of hardness and alkalinity in water is represented by the content of CaCO3, and the test methods for hardness and alkalinity refer to GB / T 45131 - 2025.

[0060] According to the present invention, preferably, the pH of the circulating water is 5 - 9.

[0061] In the present invention, the composition can still play a high corrosion inhibition and scale inhibition role in acidic water bodies.

[0062] Further preferably, the pH of the circulating water is 6 - 8.

[0063] [[ID=J39]]In the present invention, the dosage of the composition can be determined according to the water quality and water volume of the circulating water.

[0064] According to the present invention, preferably, the dosage of the composition is 0.4 - 0.7 g per kilogram of circulating water. The dosage is based on the dry basis of the composition.

[0065] The third aspect of the present invention provides the application of the composition as described above and / or the treatment method as described above in a circulating water system.

[0066] In the present invention, the composition or the treatment method can be applied to any circulating water system in the art. The water quality of the circulating water system can be as described above.

[0067] The present invention will be described in detail below through examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention, rather than to limit the present invention.

[0068] Unless otherwise specified, the reagents and materials used in the following examples are all purchased from regular chemical reagent suppliers, and the purity is analytical pure.

[0069] In the following examples, unless otherwise specified, the Schiff base compound is obtained by the following synthesis method: Mix 3,5-dihydroxy salicylaldehyde and p-phenylenediamine in a molar ratio of 2.1:1, dissolve them with an appropriate amount of ethanol, then add 1 wt‰ of formic acid based on the mass of terephthalic acid, heat to 80 °C and react for 48 hours. After the reaction is completed, cool naturally, vacuum concentrate the ethanol phase until a large amount of solid precipitates, and purify the obtained solid with a chromatography column to obtain a yellow solid.

[0070] In the following examples, sodium polyacrylate is purchased from Macklin Reagent, with the product number MKL-767418;

[0071] Sodium polymaleate is purchased from Macklin Reagent, with the product number MKL-P815905;

[0072] Polyepoxysuccinic acid is purchased from Macklin Reagent, with the product number MKL-P923986.

[0073] In the following examples, the test method for the corrosion rate (carbon steel, stainless steel, pure copper) refers to GB / T18175 - 2014.

[0074] The test method for the scale inhibition rate refers to GB / T16632 - 2019.

[0075] Example 1

[0076] Add 150 g of diethanolamine, 50 g of sodium gluconate, 10 g of thiourea, 10 g of benzotriazole, 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol), 10 g of cerium nitrate, 10 g of sodium nitrite, 30 g of polymaleic acid sodium salt, and 30 g of diethylenetriaminepentaacetic acid sodium salt to 694 g of pure water. Heat the mixture to 60 °C, stir for one hour, and then let it stand and cool down to obtain Composition A1.

[0077] Example 2

[0078] Add 150 g of triethanolamine, 50 g of zinc gluconate, 10 g of benzotriazole, 10 g of methylbenzotriazole, 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol), 10 g of rhenium nitrate, 10 g of sodium nitrate, 10 g of sodium nitrite, 10 g of sodium molybdate, 30 g of polymaleic acid sodium salt, and 30 g of polyepoxysuccinic acid to 674 g of water. Heat the mixture to 60 °C, stir for one hour, and then let it stand and cool down to obtain Composition A2.

[0079] Example 3

[0080] Add 100 g of triethanolamine, 50 g of cyclohexylamine, 50 g of sodium gluconate, 10 g of thiourea, 10 g of benzotriazole, and 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol) to 634 g of water. Heat the mixture to 60 °C, stir for one hour, and then let it stand and cool down to obtain Composition A3.

[0081] Example 4

[0082] Add 150 g of ethanolamine, 50 g of sodium gluconate, 10 g of thiourea, 10 g of benzotriazole, and 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol) to 684 g of water. Heat the mixture to 60 °C, stir for one hour, and then let it stand and cool down to obtain Composition A4.

[0083] Example 5

[0084] Add 100 g of ethanolamine, 80 g of sodium gluconate, 60 g of cyclohexylamine, 10 g of thiourea, 10 g of benzotriazole, 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol), 10 g of sodium nitrate, 10 g of sodium tungstate, 20 g of polymaleic acid sodium salt, 15 g of diethylenetriaminepentaacetic acid pentasodium salt, and 15 g of polyepoxysuccinic acid to 664 g of water. Heat the mixture to 60 °C, stir for one hour, and then let it stand and cool down to obtain Composition A5.

[0085] Example 6

[0086] Add 150 g of diethanolamine, 50 g of sodium gluconate, 10 g of thiourea, 10 g of benzotriazole, 10 g of cerium nitrate, 10 g of sodium nitrite, 30 g of polymaleic acid sodium salt, and 30 g of diethylenetriaminepentaacetic acid sodium salt to 694 g of pure water. Heat the mixture to 60 °C, stir for one hour, and then let it stand and cool down to obtain Composition A6.

[0087] Example 7

[0088] 150 g of diethanolamine, 10 g of benzotriazole, 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol), 10 g of sodium nitrite, 30 g of polymaleic acid sodium, and 30 g of diethylenetriaminepentaacetic acid sodium were added to 764 g of pure water. After stirring at 60 °C for one hour, it was allowed to stand and cool down to obtain Composition A7.

[0089] Example 8

[0090] 50 g of diethanolamine, 50 g of sodium gluconate, 10 g of thiourea, 10 g of benzotriazole, 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol), 20 g of cerium nitrate, 20 g of sodium nitrite, 30 g of polymaleic acid sodium, and 20 g of diethylenetriaminepentaacetic acid sodium were added to 694 g of pure water. The temperature was raised to 60 °C, stirred for one hour, and then allowed to stand and cool down to obtain Composition A8.

[0091] Example 9

[0092] 100 g of ethanolamine, 80 g of sodium gluconate, 60 g of cyclohexylamine, 10 g of thiourea, 10 g of benzotriazole, 1 g of Schiff base compound (dissolved in 5 g of ethylene glycol), 10 g of sodium nitrate, 10 g of sodium tungstate, 20 g of polymaleic acid sodium, 15 g of diethylenetriaminepentaacetic acid pentasodium, and 15 g of polyepoxysuccinic acid were added to 664 g of water. The temperature was raised to 60 °C. After stirring for one hour, it was allowed to stand and cool down to obtain Composition A9.

[0093] The structural formula of the Schiff base compound used in this example is:

[0094]

[0095] This Schiff base compound was synthesized by the following method: Salicylaldehyde and aniline were mixed in a molar ratio of 1:1, dissolved in an appropriate amount of ethanol, then 1 wt‰ of formic acid based on the mass of terephthalic acid was added, and the mixture was heated to 80 °C and reacted for 48 hours. After the reaction was completed, it was naturally cooled. The ethanol phase was concentrated in vacuo until a large amount of solid precipitated, and the obtained solid was purified by a chromatography column to obtain a solid.

[0096] Test Example 1

[0097] Preparation of the water sample: Calcium chloride and sodium bicarbonate standard solutions were added to deionized water to make the pH of the water sample 7.5 and the CaCO3 content 300 ppm.

[0098] The composition was added to 200 ml of the prepared water sample for corrosion rate and scale inhibition rate experiments. The water sample without the addition of the composition was used as a blank control group.

[0099] The test results after adding the composition for 3 days are shown in Table 1.

[0100] Table 1

[0101]

[0102] Test Example 2

[0103] Configuration of the water sample: Calcium chloride and sodium bicarbonate standard solutions were added to deionized water to make the pH of the water sample 7.5 and the content of CaCO3 300 ppm.

[0104] Composition A5 was added to 200 ml of the prepared water sample for the corrosion rate experiment. The experiment was carried out for 21 days, and samples were taken every 3 days for testing. The composition provided by the present invention can continuously exert the corrosion inhibition effect within 21 days (as Figure 1 shown).

[0105] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A composition with scale inhibition and corrosion inhibition functions, characterized in that, The composition comprises a first component, a second component, a third component, a fourth component and an optional Schiff base compound; The first component is selected from at least one of C2-C6 alkanolamines, C4-C8 cycloamines, nitrogen-containing heterocyclic compounds and gluconates; The second component is selected from at least one of benzotriazole compounds, benzothiazole compounds and thiourea compounds; The third component is an inorganic metal salt; The fourth component is selected from at least one of sodium acetate compounds, sodium polyacrylate, sodium polymaleate and polyepoxysuccinic acid; 2. The composition according to claim 1, wherein The C2-C6 alkanolamines include at least one of monoethanolamine, diethanolamine, triethanolamine, isopropanolamine and isobutanolamine; And / or, the C4-C8 cycloamines include at least one of cyclopentylamine, cyclohexylamine and cycloheptylamine; And / or, the nitrogen-containing heterocyclic compounds include at least one of oleic acid imidazoline, methylimidazole and 3-amino-1,2,4-triazole; And / or, the gluconates include at least one of sodium gluconate, potassium gluconate and zinc gluconate; And / or, the benzotriazole compounds include at least one of benzotriazole, methylbenzotriazole and hydroxybenzotriazole; And / or, the benzothiazole compounds include at least one of mercaptobenzothiazole, 2-hydroxybenzothiazole and sodium mercaptobenzothiazole; And / or, the thiourea compounds include at least one of thiourea, semicarbazide hydrochloride, thiosemicarbazide and amidinothiourea; And / or, the inorganic metal salts include at least one of cerium nitrate, rhenium nitrate, sodium nitrate, sodium nitrite, sodium molybdate and sodium tungstate; And / or, the sodium acetate compounds include at least one of tetrasodium glutamate diacetate, tetrasodium ethylenediaminetetraacetate and pentasodium diethylenetriaminepentaacetate; 3. The composition according to claim 1, wherein, The composition comprises a first component, a second component, a third component, a fourth component and a Schiff base compound; The first component is monoethanolamine, sodium gluconate and optional cyclohexylamine. Preferably, the weight ratio of monoethanolamine to sodium gluconate is (1.25-3):1; The second component is benzotriazole and thiourea. Preferably, the weight ratio of the two is (1-1.2):1; The third component is sodium tungstate and sodium nitrate. Preferably, the weight ratio of the two is (1-1.2):1; The fourth component is sodium polymaleate, pentasodium diethylenetriaminepentaacetate and polybutanedioic acid. Preferably, the weight ratio of the three is (1-1.5):(1-1.5):1; 4. The composition according to claim 1 or 2, wherein The weight ratio of the first component, the second component, the third component, the fourth component and the Schiff base compound is 1:0.05-0.20:0.08-0.25:0.2-0.4:0-0.008, preferably 1:0.05-0.15:0.10-0.15:0.2-0.3:0.005-0.008; 5. The composition according to claim 1 or 2, wherein The composition does not contain phosphorus element; 6. The composition according to claim 1 or 2, wherein, ​ 7. A method for treating circulating water, characterized in that, ​ ​ 8. The processing method according to claim 7, wherein, The total content of hardness and alkalinity in the circulating water is 100 - 600 ppm in terms of CaCO3; and / or, the pH of the circulating water is 5 - 9.

9. The processing method according to claim 7 or 8, wherein The dosage of the composition is 0.4 - 0.7 g relative to each kilogram of the circulating water.

10. Use of the composition according to any one of claims 1 - 6 and / or the treatment method according to any one of claims 7 - 9 in a circulating water system.

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