Composite corrosion and scale inhibitor, preparation method and application thereof

Abstract

This invention discloses a composite corrosion and scale inhibitor, its preparation method, and its application. It is composed of N,N'-piperazine di(methylenephosphonic acid), a sodium styrene sulfonate / aspartic acid / maleic acid terpolymer, zinc salt, and water. N,N'-piperazine di(methylenephosphonic acid) is prepared by reacting anhydrous piperazine, phosphorous acid, and formaldehyde. The terpolymer is a copolymer of sodium styrene sulfonate, aspartic acid, and maleic acid. This invention achieves excellent corrosion and scale inhibition performance at relatively low dosages, and its preparation method is simple, showing broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of industrial circulating cooling water treatment technology, specifically to a composite corrosion and scale inhibitor, its preparation method, and its application. Background Technology

[0002] With the global water shortage becoming increasingly severe, the demand for industrial water is constantly increasing, especially in water-intensive industries such as energy and chemicals, where water consumption is particularly large. However, water quality issues are becoming increasingly prominent in industrial water use, particularly in circulating cooling water systems. Scale formation and corrosion are common and serious water quality problems in cooling water systems. Scale formation not only reduces heat exchange efficiency but also causes poor heat conduction on equipment surfaces, thereby increasing energy consumption and shortening equipment lifespan. Corrosion damages metal materials, increasing equipment maintenance and replacement costs, and may also lead to system failures, affecting production stability.

[0003] To address the aforementioned issues, adding corrosion and scale inhibitors to circulating cooling water is a common and effective water treatment method. Especially given the current water scarcity, the application of corrosion and scale inhibitors undoubtedly provides a more sustainable and economical solution for industrial water use.

[0004] In the field of industrial circulating water treatment, hydroxyethylidene diphosphonic acid (HEDP) is widely used due to its long-lasting scale inhibition properties, but its inherent defects severely restrict sustainable development. This substance has a high phosphorus content, and long-term addition can easily lead to eutrophication of water bodies. The carbon-phosphorus bonds in its molecular structure break, forming recalcitrant phosphates, requiring the addition of precipitants for end-of-pipe treatment in traditional processes, significantly increasing treatment costs. More importantly, HEDP has weak anti-interference ability; when the iron ion concentration in the system exceeds 3 mg / L, its corrosion inhibition performance decreases exponentially with increasing iron ion concentration, leading to frequent red rust on pipe walls. 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, its preparation method and application, which can achieve good corrosion and scale inhibition performance at a low dosage, and the preparation method is simple and has broad application prospects.

[0006] To address the aforementioned technical problems, this invention provides a method for preparing a composite corrosion and scale inhibitor, as follows:

[0007] N,N'-piperazine di(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer and zinc salt were added sequentially to deionized water and mixed evenly to obtain a composite corrosion and scale inhibitor.

[0008] The material is composed of the following components:

[0009] N,N'-piperazine di(methylenephosphonic acid): 5-10%;

[0010] Sodium styrene sulfonate / aspartic acid / maleic acid terpolymer: 10-20%;

[0011] Zinc salt: 5-10%;

[0012] The rest is water.

[0013] Furthermore, the chemical formula of the N,N'-piperazine di(methylenephosphonic acid) is C6H. 16 N2O6P2 is prepared by reacting anhydrous piperazine, phosphorous acid and formaldehyde.

[0014] Furthermore, 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;

[0015] The mass ratio of maleic acid, aspartic acid, sodium styrene sulfonate, and initiator is 1:(0.55-1.15):(0.08-0.18):(0.035-0.12).

[0016] The reaction conditions were as follows: copolymerization was achieved by stirring at 90°C for 4 hours at pH=9.

[0017] Furthermore, the initiator is one or more of benzoyl peroxide, tert-butyl hydroperoxide, isobutyl peroxide dicarbonate, and potassium persulfate.

[0018] Furthermore, the zinc salt includes one or more of zinc sulfate and zinc chloride.

[0019] A composite corrosion and scale inhibitor, wherein the composite corrosion and scale inhibitor is obtained by the preparation method described above;

[0020] The application of a composite corrosion and scale inhibitor in a circulating cooling water system shows that when added to the circulating cooling water system, it can simultaneously achieve the effects of corrosion inhibition and scale inhibition.

[0021] The beneficial effects of this invention are as follows: 1. The bisphosphonic acid group in the structure of the organophosphonic acid compound N,N'-piperazine di(methylenephosphonic acid) disclosed in this application can form a polydentate coordination system with the nitrogen lone pair electrons. This system not only has a very strong chelating effect on calcium and magnesium ions in water, but also on Fe. 3+ It forms a stable complex, effectively blocking the catalytic oxidation chain reaction of rust.

[0022] 2. Since the composite scale inhibitor disclosed in this application contains N,N'-piperazine di(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer and zinc salt, it has both corrosion inhibition and scale inhibition effects. When treating circulating cooling water, only a certain amount of this compound agent needs to be added to the liquid, which is more scientific and environmentally friendly.

[0023] 3. The phosphorus content in the phosphonic acid compounds for water treatment disclosed in this application is lower than that in HEDP, and the stability is better than that in HEDP. It can effectively alleviate environmental problems such as eutrophication of water bodies after use, and has a strong resistance to iron ion interference.

[0024] 4. The composite scale inhibitor disclosed in this application has a simple synthesis process and has good application prospects in the field of industrial circulating cooling water treatment. It also provides a new idea for developing green and efficient circulating cooling water treatment agents. Attached Figure Description

[0025] Figure 1 The results are infrared spectra of N,N'-piperazine di(methylenephosphonic acid) prepared in Example 1.

[0026] Figure 2 This is the infrared spectrum of the prepared sodium styrene sulfonate / aspartic acid / maleic acid terpolymer.

[0027] Figure 3 It is the structural formula of N,N'-piperazine di(methylenephosphonic acid).

[0028] Figure 4 The structural formula of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is...

[0029] Figure 5 These are performance test data for a composite corrosion and scale inhibitor. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, 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 number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] Reference Figures 1 to 5 As shown, Figure 1 This is the infrared spectrum of the N,N'-piperazine di(methylenephosphonic acid) compound. The spectrum shows the 3200-2800 cm⁻¹... -1 This is a stretching vibration of the OH bond, 1448 cm⁻¹ -1 The point belongs to the bending vibration of -CH2, 1263cm. -1 The point belongs to the stretching vibration of CN, 1130 cm. -1 and 917cm -1 The vibration belongs to the phosphate group.

[0037] 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... -1 The point is the stretching vibration of the NH bond, 1578 cm⁻¹. -1 and 1399 cm -1 The stretching vibrations at points C=O and CN in the amide bond, respectively, indicate that aspartic acid successfully polymerized with maleic acid. Furthermore, at 1600-1700 cm⁻¹... -1 No C=C bond peak was observed at this location, indicating that the C=C bonds in sodium styrene sulfonate and maleic acid broke and polymerized. (1137 cm⁻¹) -1 The presence of S=O bond stretching vibrations at this point indicates the presence of sulfonic acid groups in the polymerization product, suggesting that sodium styrene sulfonate participated in the copolymerization reaction. These results demonstrate the successful synthesis of the sodium styrene sulfonate / aspartic acid / maleic acid terpolymer.

[0038] Figure 4 In this equation, a, b, and c are all integers from 1 to 10. Sodium styrene sulfonate and maleic acid undergo polymerization through carbon-carbon double bonds, and aspartic acid is linked to the side chain by forming amide bonds with maleic acid.

[0039] The mass ratio of the total mass of the reactants to the mass of water is 1:1.8-2.2.

[0040] Example 1:

[0041] The preparation of N,N'-piperazine di(methylenephosphonic acid) compound includes: 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, stirring until homogeneous, and then slowly adding 35 mL of formaldehyde solution (37-40% concentration) dropwise to the mixture; heating under reflux at 120 °C for 10 h. After the reaction is complete, N,N'-piperazine di(methylenephosphonic acid) is obtained by filtration, washing, and drying.

[0042] Preparation of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer: 11.6070 g of maleic acid, 9.9825 g of aspartic acid, and 15.4643 g of sodium styrene sulfonate were weighed and added to 65 mL of water. The mixture was stirred continuously at 90 °C, and sodium hydroxide was added to the reaction system until the pH reached approximately 9. 0.9128 g of benzoyl peroxide was weighed, dissolved in 10 mL of ethanol, and added to a constant pressure dropping funnel. Under a nitrogen atmosphere, ammonium persulfate solution was slowly added dropwise first, followed by sodium sulfite solution. After stirring continuously for 4 hours, the reaction was completed, yielding the sodium styrene sulfonate / aspartic acid / maleic acid terpolymer.

[0043] A composite corrosion and scale inhibitor and its preparation method include: sequentially adding N,N'-piperazine di(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer and zinc sulfate to deionized water, and mixing them evenly to obtain the above-mentioned composite corrosion and scale inhibitor.

[0044] In the composite corrosion and scale inhibitor, by weight, the amount of N,N'-piperazine di(methylenephosphonic acid) is 5 parts, the amount of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is 10 parts, the amount of zinc sulfate is 5 parts, and the amount of pure water is 80 parts.

[0045] Example 2:

[0046] The difference between a composite corrosion and scale inhibitor and its preparation method and Example 1 is as follows: In the composite corrosion and scale inhibitor, by weight, the amount of N,N'-piperazine di(methylenephosphonic acid) is 7.5 parts, the amount of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is 15 parts, the amount of zinc sulfate is 7.5 parts, and the amount of pure water is 70 parts.

[0047] Example 3:

[0048] The difference between a composite corrosion and scale inhibitor and its preparation method and Example 1 is as follows: In the composite corrosion and scale inhibitor, by weight, the amount of N,N'-piperazine di(methylenephosphonic acid) is 10 parts, the amount of sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is 20 parts, the amount of zinc sulfate is 10 parts, and the amount of pure water is 60 parts.

[0049] Corrosion and scale inhibition performance test

[0050] The corrosion inhibition performance of the composite corrosion and scale inhibitor disclosed in this invention was determined according to the standard GB / T18175-2014 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotary Coated Plate Method", and the scale inhibition performance was determined according to the standard GB / T16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". The test results are as follows: Figure 5 As shown, from Figure 5 Data shows that the composite corrosion and scale inhibitor prepared by the method disclosed in this application can achieve excellent corrosion and scale inhibition effects when applied to a circulating cooling water treatment system.

[0051] The embodiments described above are merely preferred embodiments for fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A method for preparing a composite corrosion and scale inhibitor, characterized in that, The method is as follows: N,N'-piperazine di(methylenephosphonic acid), sodium styrene sulfonate / aspartic acid / maleic acid terpolymer and zinc salt were added sequentially to deionized water and mixed evenly to obtain a composite corrosion and scale inhibitor. The material is composed of the following components: N,N'-piperazine di(methylenephosphonic acid): 5-10%; Sodium styrene sulfonate / aspartic acid / maleic acid terpolymer: 10-20%; Zinc salt: 5-10%; The rest is water.

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

3. The preparation method of the composite corrosion and scale inhibitor as described in claim 1, characterized in that, The sodium styrene sulfonate / aspartic acid / maleic acid terpolymer is formed by copolymerization of 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 initiator is 1:(0.55-1.15):(0.08-0.18):(0.035-0.12). The reaction conditions were as follows: copolymerization was achieved by stirring at 90°C for 4 hours at pH=9.

4. The method for preparing the composite corrosion and scale inhibitor according to claim 3, characterized in that, The initiator is one or more of benzoyl peroxide, tert-butyl hydroperoxide, isobutyl peroxide dicarbonate, and potassium persulfate.

5. The preparation method of the composite corrosion and scale inhibitor as described in 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. The application of the composite corrosion and scale inhibitor as described in claim 6 in a circulating cooling water system.

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