A polymer scale inhibitor and a preparation method thereof

Abstract

The present application relates to the technical field of polymer and water treatment, and discloses a polymer scale inhibitor and a preparation method thereof. The scale inhibitor is prepared by polymerization of double nitrogen diacetamide and bisacrylamide as monomers. The scale inhibitor has high scale inhibition efficiency, environmental friendliness, monitorability and easy production, can effectively solve the problems of scale formation, environmental protection and monitoring difficulty of the cooling system of a converter valve and industrial circulating cooling water, and has high practical application value.

Description

Technical Field

[0001] This invention relates to the fields of polymer and water treatment technology, and in particular to a polymer scale inhibitor and its preparation method. Background Technology

[0002] In industrial production, scaling in circulating cooling water systems is a common problem that has long plagued the stable operation of equipment. With the increasing demand for large-scale grid connection of new energy sources, the construction and operation scale of converter stations continues to expand, and the cooling system of its core equipment—the converter valve—also faces a severe scaling challenge.

[0003] Converter valves are key components ensuring the safe and stable operation of the power grid. Their cooling systems must continuously absorb heat from core components such as thyristors and IGBTs to prevent damage due to excessive temperature rise. The heat absorbed by the system is ultimately exchanged between the sprayed water and air through the heat exchange coils of the spray cooling tower, and then dissipated into the atmosphere, achieving circulating cooling. However, during operation, the heat exchange coils are highly susceptible to scaling due to mineral deposits in the water (e.g., the thermal conductivity of carbonate scale is only 1 / 30 that of stainless steel), leading to a sharp decline in heat exchange efficiency and deterioration of cooling effect. This directly threatens the stable operation of the converter valve and may even cause power grid failures.

[0004] Currently, the industry mainly alleviates scaling problems by adding scale inhibitors to cooling water and regularly draining water to reduce its salinity. With increasingly stringent environmental regulations, biodegradable and environmentally friendly scale inhibitors (such as polyaspartic acid and polyepoxysuccinic acid) have become the mainstream direction for application and research. These scale inhibitors rely on amide bonds and carboxyl groups on their molecular chains to chelate with metal ions, achieving basic scale inhibition and corrosion inhibition effects. However, limited by their single molecular structure, their scale inhibition efficiency and applicable operating conditions still have room for improvement.

[0005] Meanwhile, the practical application of scale inhibitors also faces the challenge of "difficulty in concentration monitoring": the converter valve cooling system lacks effective real-time monitoring methods for scale inhibitor concentration. Currently, it mainly relies on the experience of technicians to add it periodically. This method is prone to excessive waste of scale inhibitors and may also lead to scaling risks due to insufficient addition, which cannot meet the high-precision operation requirements of the converter station cooling system.

[0006] Therefore, developing a scale inhibitor that combines high scale inhibition performance, environmental friendliness, and concentration monitoring capability is of great significance for solving the scaling problem in converter valve cooling systems. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a poly(amide-pyrazoline) polymer scale inhibitor and its preparation method. The resulting scale inhibitor not only has good scale inhibition performance, but is also a biodegradable and environmentally friendly scale inhibitor, and also has fluorescent properties, which facilitates continuous monitoring in practical applications.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A polymeric scale inhibitor has the following general structural formula:

[0010]

[0011] In the formula, R1 is a straight-chain aliphatic hydrocarbon of C1 to C4, and R2 is a straight-chain aliphatic hydrocarbon of C1 to C3.

[0012] Furthermore, the range of n is 10 to 100.

[0013] Furthermore, when the concentration of the polymeric scale inhibitor is 6 mg / mL, the scale inhibition rate for calcium carbonate and calcium sulfate is ≥99.5%.

[0014] In addition, the present invention also provides a method for preparing the above-mentioned polymeric scale inhibitor, the synthetic route of which is as follows:

[0015]

[0016] The preparation method includes the following steps:

[0017] Diazinon and bisacrylamide were added to N,N-dimethylformamide and the mixture was stirred and reacted at a preset temperature.

[0018] Stop the reaction when the reaction system turns colorless;

[0019] The reaction system was transferred to tetrahydrofuran for purification, and then centrifuged and dried to obtain the polymer scale inhibitor.

[0020] Furthermore, the molar ratio of the diazideacetamide and bisacrylamide is 1:1.

[0021] Furthermore, the volume of N,N-dimethylformamide is twice the total volume of diazonium diacetamide and bisacrylamide; the volume of tetrahydrofuran is five times the volume of N,N-dimethylformamide.

[0022] Furthermore, the preset temperature is 30~40℃; the reaction time is 6~8 h.

[0023] Furthermore, the centrifugation speed is 8000 r / min.

[0024] Furthermore, the structural formula of the diacetamide is as follows:

[0025]

[0026] In the formula, R1 is a straight-chain aliphatic hydrocarbon of C1 to C4.

[0027] Furthermore, the structural formula of the bisacrylamide is as follows:

[0028]

[0029] In the formula, R2 is a C1~C3 straight-chain aliphatic hydrocarbon.

[0030] Compared to existing technologies, the preparation process of this invention is simple and suitable for industrial-scale production. The preparation method of this invention uses diacetamide and bisacrylamide as monomers, and polymerization can be completed through a mild 1,3-dipolar cycloaddition reaction. The reaction conditions (30~40℃, 6~8 h) are easily controlled, the purification steps (tetrahydrofuran precipitation + centrifugation) are simple to operate, requiring no complex equipment, and the monomer conversion rate is high, with stable product purity, facilitating industrial mass production to meet the needs of large-scale applications such as converter stations.

[0031] This invention has the following significant advantages:

[0032] Excellent scale inhibition performance, suitable for the high demands of converter valve cooling systems: The scale inhibitor of this invention contains both −NH− and pyrazoline groups in its molecular structure, which can inhibit scale formation through the dual effects of coordination complexation and steric hindrance; combined with the short-chain aliphatic hydrocarbon design and polymerization degree range of R1 and R2, the water solubility of the molecule and the density of functional groups are guaranteed. At a low usage concentration of 6 mg / mL, the scale inhibition rate for calcium carbonate and calcium sulfate is ≥99.5%, which is far superior to traditional polyaspartic acid scale inhibitors. It can effectively solve the scaling problem of converter valve cooling coils and maintain a stable heat transfer coefficient.

[0033] With outstanding environmental friendliness and compliance with stringent environmental protection requirements, this scale inhibitor is biodegradable. Its molecular chain length and amide bond structure are adapted to the decomposition and metabolic needs of microorganisms, and it will not accumulate pollution in the environment after use. Compared with traditional difficult-to-degrade scale inhibitors, it is more in line with the current trend of environmental legislation and green industrial production, and is suitable for continuous application in large-scale long-term operation scenarios such as converter stations.

[0034] With built-in fluorescent labeling, the scale inhibitor concentration can be conveniently monitored: The pyrazoline group of the scale inhibitor in this invention gives it stable fluorescence properties (maximum emission wavelength 465nm). The linear correlation between fluorescence intensity and concentration can be used to quickly and accurately detect the scale inhibitor content in cooling water, replacing the traditional "experience-based addition" method. This avoids the waste of excessive scale inhibitor and prevents the risk of scaling caused by insufficient addition, significantly improving the controllability and economy of the converter valve cooling system.

[0035] In summary, the scale inhibitor of the present invention has high scale inhibition efficiency, environmental friendliness, monitorability and ease of production, and can effectively solve the problems of scaling, environmental protection and monitoring in converter valve cooling systems and industrial circulating cooling water, and has extremely high practical application value. Attached Figure Description

[0036] Figure 1 The image shows the proton NMR spectrum of the scale inhibitor prepared in Example 1 of this invention.

[0037] Figure 2 The infrared absorption spectrum of the scale inhibitor prepared in Example 1 of this invention is shown.

[0038] Figure 3 The fluorescence spectrum of the scale inhibitor prepared in Example 1 of this invention is shown. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] To better illustrate the polymer scale inhibitor and its preparation method provided by the present invention, further examples are given below.

[0041] Example 1

[0042] This invention provides a method for preparing a polymeric scale inhibitor, the method comprising the following steps:

[0043] 4 mmol of diacetyl-1,3-propanediamine and 4 mmol of N,N'-methylenebisacrylamide were added to N,N-dimethylformamide in a volume twice the total volume of the above reactants. The mixture was stirred at 30°C and the reaction was stopped when the color of the reaction system turned colorless. The reaction took 8 hours.

[0044] The above reaction system was added dropwise to tetrahydrofuran at a volume of 5 times that of N,N-dimethylformamide for purification. The purified solution was then centrifuged at 8000 r / min and vacuum dried to obtain poly(amide-pyrazoline) scale inhibitor 1, i.e., a polymeric scale inhibitor. The yield was calculated to be 92%.

[0045] The scale inhibitor 1 obtained in Example 1 was subjected to nuclear magnetic resonance (NMR), and its proton NMR spectrum is shown below. Figure 1As shown, the deuterated reagent used was d6-DMSO. The peaks at 8.40-8.53 ppm represent the NH proton peaks contained in the polymer structure; at 4.42 ppm, the peak from the CH2 group in bisacrylamide (-NHCH2NH-); at 4.33 ppm, the peak from the CH group on the pyrazoline ring connected to NH; at 3.62 ppm, the peaks from the two CH2 groups connected to NH in diazonium diacetyl-1,3-propanediamine (-NHCH2-CH2-CH2NH-); at 2.84-3.02 ppm, the peaks from the CH2 group on the pyrazoline ring; and at 1.93 ppm, the peak from the CH2 group on diazonium diacetyl-1,3-propanediamine separated from NH by a methylene group (-NHCH2-CH2-CH2NH-).

[0046] The scale inhibitor 1 obtained in Example 1 was subjected to infrared detection, and its infrared absorption spectrum is shown below. Figure 2 As shown, 3302 and 1537 cm -1 The absorption peaks at 1624-1653 cm⁻¹ represent the stretching and bending vibration peaks of NH, respectively. -1 The peak at this point represents the stretching vibration of the carbonyl group.

[0047] The scale inhibitor 1 obtained in Example 1 was subjected to fluorescence testing, and its fluorescence spectrum is shown below. Figure 3 As shown, the test conditions were: in pure water, at a concentration of 0.2 mg / mL. -1 With an excitation wavelength of 363 nm and a slit width of 2 nm, the resulting scale inhibitor exhibited maximum emission intensity at 465 nm. The fluorescence photographs inserted in the spectrum were taken of the above solution under 365 nm ultraviolet light irradiation.

[0048] The instruments used for the above characterization were as follows: the proton nuclear magnetic resonance spectrum was measured at room temperature using a 400 MHz JEOL-JNM-ECZ400 S / II nuclear magnetic resonance spectrometer; the Fourier transform infrared spectrum (FTIR) was measured using an IS50 Fourier transform infrared spectrometer (ATR-FTIR); and the fluorescence emission spectrum was measured using an Edinburgh FLS 100 fluorescence spectrometer.

[0049] Example 2

[0050] This invention provides a method for preparing a polymeric scale inhibitor, the method comprising the following steps:

[0051] 4 mmol of diacetyl-1,3-propanediamine and 4 mmol of N,N'-methylenebisacrylamide were added to N,N-dimethylformamide in a volume twice the total volume of the reactants. The mixture was stirred at 40°C and the reaction was stopped when the color of the reaction system turned colorless. The reaction took 6 hours.

[0052] The above reaction system was added dropwise to tetrahydrofuran at a volume five times that of N,N-dimethylformamide for purification. The purified solution was then centrifuged at 8000 r / min and vacuum dried to obtain a poly(amide-pyrazoline) scale inhibitor, i.e., a polymeric scale inhibitor. The yield was calculated to be 82%.

[0053] Example 3

[0054] This invention provides a method for preparing a polymeric scale inhibitor, the method comprising the following steps:

[0055] 4 mmol of diacetyl-1,2-ethylenediamine and 4 mmol of N,N'-methylenebisacrylamide were added to N,N-dimethylformamide in a volume twice the total volume of the above reactants. The mixture was stirred at 35°C and the reaction was stopped when the color of the reaction system turned colorless. The reaction took 7 hours.

[0056] The above reaction system was added dropwise to tetrahydrofuran at a volume of 5 times that of N,N-dimethylformamide for purification. The purified solution was then centrifuged at 8000 r / min and vacuum dried to obtain poly(amide-pyrazoline) scale inhibitor 2. The yield was calculated to be 86%.

[0057] Example 4

[0058] This invention provides a method for preparing a polymeric scale inhibitor, the method comprising the following steps:

[0059] 4 mmol of diacetyl-1,2-ethylenediamine and 4 mmol of N,N'-(propane-1,3-diyl)diacrylamide were added to N,N-dimethylformamide in a volume twice the total volume of the above reactants. The mixture was stirred at 30°C and the reaction was stopped when the color of the reaction system turned colorless. The reaction took 8 hours.

[0060] The above reaction system was added dropwise to tetrahydrofuran at a volume of 5 times that of N,N-dimethylformamide for purification. The purified solution was then centrifuged at 8000 r / min and vacuum dried to obtain poly(amide-pyrazoline) scale inhibitor 3. The yield was calculated to be 89%.

[0061] Example 5

[0062] This invention provides a method for preparing a polymeric scale inhibitor, the method comprising the following steps:

[0063] 4 mmol of diazonium (methylenediacetamide) and 4 mmol of N,N'-(propane-1,3-diyl)diacrylamide were added to N,N-dimethylformamide in a volume twice the total volume of the above reactants. The mixture was stirred at 30°C and the reaction was stopped when the color of the reaction system turned colorless. The reaction took 8 hours.

[0064] The above reaction system was added dropwise to tetrahydrofuran at a volume of 5 times that of N,N-dimethylformamide for purification. The purified solution was then centrifuged at 8000 r / min and vacuum dried to obtain poly(amide-pyrazoline) scale inhibitor 4. The yield was calculated to be 90%.

[0065] Scale inhibition performance test

[0066] The scale inhibition performance of scale inhibitors 1-4 obtained in Examples 1 and 3-5 on calcium carbonate and calcium sulfate was tested. The test methods were in accordance with "SY / T 5673-2020 General Technical Conditions for Scale Inhibitors for Oilfield Use" and "GB / T 16632-2019 Calcium Carbonate Deposition Method". The concentration of the scale inhibitor used was 6 mg / mL. -1 The scale inhibition performance data are shown in Table 1. The obtained scale inhibitors can achieve good scale inhibition effects under the experimental conditions.

[0067] Table 1. Scale inhibition performance of scale inhibitors

[0068]

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polymeric scale inhibitor, characterized in that, The polymeric scale inhibitor has the following general structural formula: In the formula, R1 is a straight-chain aliphatic hydrocarbon of C1 to C4, R2 is a straight-chain aliphatic hydrocarbon of C1 to C3, and n ranges from 10 to 100.

2. The polymeric scale inhibitor according to claim 1, characterized in that, When the concentration of the polymeric scale inhibitor is 6 mg / mL, the scale inhibition rate for calcium carbonate and calcium sulfate is ≥99.5%.

3. The method for preparing the polymeric scale inhibitor according to claim 1 or 2, characterized in that, Includes the following steps: Diazinon and bisacrylamide were added to N,N-dimethylformamide and the mixture was stirred and reacted at a preset temperature. Stop the reaction when the reaction system turns colorless; The reaction system was transferred to tetrahydrofuran for purification, and then centrifuged and dried to obtain the polymer scale inhibitor.

4. The preparation method according to claim 3, characterized in that, The molar ratio of diacetamide and bisacrylamide is 1:

1.

5. The preparation method according to claim 3, characterized in that, The volume of N,N-dimethylformamide is twice the total volume of diazonium diacetamide and bisacrylamide; the volume of tetrahydrofuran is five times the volume of N,N-dimethylformamide.

6. The preparation method according to claim 3, characterized in that, The preset temperature is 30~40℃; the reaction time is 6~8h.

7. The preparation method according to claim 3, characterized in that, The centrifuge speed is 8000 r / min.

8. The preparation method according to claim 3, characterized in that, The structural formula of the diacetamide is as follows: In the formula, R1 is a straight-chain aliphatic hydrocarbon of C1 to C4.

9. The preparation method according to claim 8, characterized in that, The structural formula of the bisacrylamide is as follows: In the formula, R2 is a C1~C3 straight-chain aliphatic hydrocarbon.

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