Composite corrosion and scale inhibitor as well as preparation method and application thereof

Abstract

The invention discloses a composite corrosion and scale inhibitor as well as a preparation method and application thereof. The composite corrosion and scale inhibitor is prepared by mixing N, N '-piperazine bis (methylene phosphonic acid), sodium p-styrenesulfonate / aspartic acid / maleic acid terpolymer, zinc salt and water. Wherein the N, N '-piperazine bis (methylenephosphonic acid) is prepared by reacting anhydrous piperazine, phosphorous acid and formaldehyde, and the terpolymer is formed by copolymerizing sodium p-styrenesulfonate, aspartic acid and maleic acid. Good corrosion and scale inhibition performance can be achieved at a low dosage, the preparation method is simple, and the corrosion and scale inhibitor has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial circulating cooling water treatment, and particularly relates to a composite corrosion and scale inhibitor, a preparation method thereof, and an application thereof. Background Art

[0002] With the increasingly serious global water shortage problem and the continuous increase in the demand for industrial water, especially in high water-consuming industries such as energy and chemical industries, the water consumption is particularly large. However, during the use of industrial water, especially in the circulating cooling water system, water quality problems are becoming increasingly prominent. Scaling and corrosion are common and seriously influential water quality problems in the cooling water system. Scaling not only reduces the heat exchange efficiency but also causes poor heat conduction on the surface of the equipment, thereby increasing energy consumption and shortening the service life of the equipment. Corrosion will damage metal materials, increase the cost of equipment maintenance and replacement, and may also lead to system failures, affecting production stability.

[0003] To solve the above problems, adding corrosion and scale inhibitors to circulating cooling water is a common and effective water treatment method. Especially in the context of water resource tension, the application of corrosion and scale inhibitors undoubtedly provides a more sustainable and economical solution for industrial water.

[0004] In the field of industrial circulating water treatment, although 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) is widely used due to its long-term scale inhibition characteristics, its inherent defects seriously restrict sustainable development. This substance has a high phosphorus content, and long-term dosing is likely to cause eutrophication of water bodies. After the carbon-phosphorus bond in its molecular structure breaks, it generates refractory phosphates, and traditional processes require additional precipitation agents for end treatment, significantly increasing the treatment cost. More critically, the anti-interference ability of HEDP is weak. When the iron ion concentration in the system exceeds 3 mg / L, its corrosion inhibition performance will decrease exponentially with the increase of the iron ion concentration, resulting in frequent occurrence of red rust on the pipe wall. These defects force the industry to seek a new generation of environmentally friendly scale inhibitors. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a composite corrosion and scale inhibitor, a preparation method thereof, and an application thereof, which can achieve good corrosion inhibition and scale inhibition performance at a lower dosage, and the preparation method is simple, having broad application prospects.

[0006] To solve the above technical problems, the present invention provides a preparation method of a composite corrosion and scale inhibitor, and the method is as follows: Add N,N'-piperazine bis(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer, and zinc salt into deionized water in sequence, and obtain a composite corrosion and scale inhibitor after mixing evenly; Meanwhile, the material consists of the following components: N,N'-piperazine bis(methylenephosphonic acid): 5-10%; Sodium styrene sulfonate / aspartic acid / maleic acid terpolymer: 10 - 20%; Zinc salt: 5 - 10%; The balance is water.

[0007] Further, the chemical formula of the N,N'-piperazine bis(methylenephosphonic acid) is C6H 16 N2O6P2, which is prepared by reacting anhydrous piperazine, phosphorous acid and formaldehyde.

[0008] Further, the sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is copolymerized from sodium styrene sulfonate, aspartic acid and maleic acid under the action of an initiator; The mass ratio of maleic acid, aspartic acid, sodium styrene sulfonate and the initiator is 1:(0.55 - 1.15):(0.08 - 0.18):(0.035 - 0.12); The reaction conditions are copolymerization by stirring at 90 °C for 4 h under the condition of pH = 9.

[0009] Further, the initiator is one or more of benzoyl peroxide, tert-butyl hydroperoxide, isobutyl peroxydicarbonate, potassium persulfate.

[0010] Further, the zinc salt includes one or more of zinc sulfate and zinc chloride.

[0011] A composite corrosion and scale inhibitor, which is obtained by the preparation method according to any one of claims 1 - 5; An application of the composite corrosion and scale inhibitor in a circulating cooling water system, which can achieve the effects of corrosion inhibition and scale inhibition simultaneously after being added to the circulating cooling water system.

[0012] Advantages of the present invention: 1. The diphosphonic acid group and the nitrogen lone pair electrons in the structure of the organic phosphonic acid compound N,N'-piperazine bis(methylenephosphonic acid) disclosed in the present application can form a multidentate coordination system, which not only has a very strong chelating effect on calcium and magnesium ions in water, but also can form a stable complex with Fe 3+ to effectively block the catalytic oxidation chain reaction of rust.

[0013] 2. Since the composite scale inhibitor disclosed in the present application contains N,N'-piperazine bis(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer and zinc salt, and has the effects of corrosion inhibition and scale inhibition at the same time, only a certain dose of this compounding agent needs to be added to the liquid during the treatment of circulating cooling water, which is more scientific and environmentally friendly; 3. The phosphonic acid compounds disclosed in this application have a lower phosphorus element content than HEDP, better stability than HEDP, can effectively alleviate environmental problems such as eutrophication of water bodies after use, and have a strong resistance to iron ion interference; 4. The synthesis process of the composite scale inhibitor disclosed in this application is simple, has good application prospects in the field of industrial circulating cooling water treatment, and also provides a new idea for developing green and efficient circulating cooling water treatment agents. Description of the Drawings

[0014] Figure 1 It is the test result of the infrared spectrum of N,N'-piperazine bis(methylenephosphonic acid) prepared in Example 1.

[0015] Figure 2 It is the infrared spectrum of the ternary copolymer of sodium styrenesulfonate / aspartic acid / maleic acid prepared.

[0016] Figure 3 It is the structural formula of N,N'-piperazine bis(methylenephosphonic acid).

[0017] Figure 4 It is the structural formula of the ternary copolymer of sodium styrenesulfonate / aspartic acid / maleic acid Figure 5 It is the performance test data of the composite corrosion and scale inhibitor. Detailed Embodiments

[0018] The present invention will be further described below with reference to the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited are not intended to limit the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0021] In the present invention, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "connected to", "fixed" and the like should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0023] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0024] Refer to Figures 1 to 5 as shown Figure 1 is the infrared spectrum of the N,N'-piperazine bis(methylenephosphonic acid) compound. As can be seen from the figure, the range of 3200 - 2800 cm -1 corresponds to the stretching vibration of the O-H bond, the 1448 cm -1 corresponds to the bending vibration of -CH2, the 1263 cm -1 corresponds to the stretching vibration of C-N, the 1130 cm -1 and 917 cm -1This is the vibration of the phosphate group.

[0025] Figure 2 This is the infrared spectrum of the prepared sodium styrene sulfonate / aspartic acid / maleic acid terpolymer. As can be seen from the figure, at 3136 cm -1 is the stretching vibration of the N-H bond, and at 1578 cm -1 and 1399 cm -1 are respectively the stretching vibrations of the C=O bond and C-N bond in the amide bond, indicating that aspartic acid has successfully polymerized with maleic acid. In addition, no peak of the C=C bond is observed at 1600 - 1700 cm -1 , indicating that the C=C in sodium styrene sulfonate and maleic acid has broken and a polymerization reaction has occurred. At 1137 cm -1 is the stretching vibration of the S=O bond, indicating the presence of sulfonic acid groups in the polymerization product, suggesting that sodium styrene sulfonate has participated in the copolymerization reaction. The above results indicate the successful synthesis of the sodium styrene sulfonate / aspartic acid / maleic acid terpolymer.

[0026] Figure 4 In a, b, and c are all integers from 1 to 10. Sodium styrene sulfonate and maleic acid polymerize through carbon-carbon double bonds, and aspartic acid is connected to the side chain by forming an amide bond with maleic acid.

[0027] The mass ratio of the total mass of the reaction monomers to the mass of water is 1:1.8 - 2.2.

[0028] Example 1: Preparation of N,N'-piperazine bis(methylenephosphonic acid) compound, including: dissolving 7.7526 g of anhydrous piperazine and 18.8600 g of phosphorous acid in 70 mL of water, slowly adding 75 mL of hydrochloric acid thereto, and after stirring evenly, slowly dropping 35 mL of formaldehyde solution (content 37 - 40%) into the above mixture; heating and refluxing at 120 °C for 10 h. After the reaction is completed, N,N'-piperazine bis(methylenephosphonic acid) is obtained by suction filtration, washing, and drying; Preparation of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer: Weigh 11.6070 g of maleic acid, 9.9825 g of aspartic acid, and 15.4643 g of sodium styrene sulfonate and add them to 65 mL of water. Stir continuously at 90 °C, and add sodium hydroxide to the reaction system until the pH is about 9. Weigh 0.9128 g of benzoyl peroxide, dissolve it in 10 mL of ethanol, and then add it to the constant pressure dropping funnel. Under the protection of nitrogen atmosphere, first slowly drop the ammonium persulfate solution, and after it is dropped, slowly drop the sodium sulfite solution. After continuous stirring for 4 hours, the reaction ends to obtain the sodium styrene sulfonate / aspartic acid / maleic acid terpolymer; A composite corrosion and scale inhibitor and its preparation method, comprising: sequentially adding N,N'-piperazine bis(methylene phosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer, and zinc sulfate into deionized water, and mixing evenly to obtain the above-mentioned composite corrosion and scale inhibitor.

[0029] Among them, in the composite corrosion and scale inhibitor, by weight, the dosage of N,N'-piperazine bis(methylene phosphonic acid) is 5 parts, the dosage of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is 10 parts, the dosage of zinc sulfate is 5 parts, and the dosage of pure water is 80 parts.

[0030] Example 2: The difference between a composite corrosion and scale inhibitor and its preparation method and Example 1: In the composite corrosion and scale inhibitor, by weight, the dosage of N,N'-piperazine bis(methylene phosphonic acid) is 7.5 parts, the dosage of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is 15 parts, the dosage of zinc sulfate is 7.5 parts, and the dosage of pure water is 70 parts.

[0031] Example 3: The difference between a composite corrosion and scale inhibitor and its preparation method and Example 1: In the composite corrosion and scale inhibitor, by weight, the dosage of N,N'-piperazine bis(methylene phosphonic acid) is 10 parts, the dosage of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is 20 parts, the dosage of zinc sulfate is 10 parts, and the dosage of pure water is 60 parts.

[0032] Corrosion and scale inhibition performance test The corrosion inhibition performance of the composite corrosion and scale inhibitor disclosed in the present invention was determined by referring to the method of GB / T18175-2014 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Specimen Method", and the scale inhibition performance was determined by referring to the method of GB / T16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". The test results are as Figure 5 shown. From Figure 5 the data, it can be seen that the composite corrosion and scale inhibitor prepared by the method disclosed in this application can obtain good corrosion and scale inhibition effects when applied to the treatment system of circulating cooling water.

[0033] The above-mentioned embodiments are only preferred embodiments cited to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A preparation method of a composite corrosion and scale inhibitor, characterized in that, The method is as follows: Add N,N'-piperazine bis(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer, and zinc salt into deionized water in sequence. After mixing evenly, a composite corrosion and scale inhibitor is obtained; Meanwhile, the material consists of the following components: N,N'-piperazine bis(methylenephosphonic acid): 5-10%; Sodium styrene sulfonate / aspartic acid / maleic acid terpolymer: 10-20%; Zinc salt: 5-10%; The balance is water.

2. The preparation method of the composite corrosion inhibitor and scale inhibitor according to claim 1, characterized in that The chemical formula of the N,N'-piperazine bis(methylenephosphonic acid) is C6H 16 N2O6P2, which is prepared by reacting anhydrous piperazine, phosphorous acid and formaldehyde.

3. The preparation method of the composite corrosion inhibitor and scale inhibitor according to claim 1, characterized in that The sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is copolymerized from sodium styrene sulfonate, aspartic acid, and maleic acid under the action of an initiator; The mass ratio of maleic acid, aspartic acid, sodium styrene sulfonate, and the initiator is 1:(0.55-1.15):(0.08-0.18):(0.035-0.12); The reaction conditions are copolymerization by stirring at 90 °C for 4 h under the condition of pH = 9.

4. The preparation method of the composite corrosion and scale inhibitor according to claim 1, characterized in that, The initiator is one or more of benzoyl peroxide, tert-butyl hydroperoxide, isobutyl peroxydicarbonate, and potassium persulfate.

5. The preparation method of the composite corrosion inhibitor and scale inhibitor according to claim 1, characterized in that, The zinc salt includes one or more of zinc sulfate and zinc chloride.

6. A composite corrosion and scale inhibitor, characterized in that, The composite corrosion and scale inhibitor is obtained by the preparation method described in any one of claims 1-5.

7. Use of the composite corrosion and scale inhibitor according to claim 6 in a circulating cooling water system.

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