Corrosion and Scale Inhibitor and Its Preparation Method

Abstract

The present invention discloses a corrosion and scale inhibitor and a preparation method thereof, belonging to the technical field of oilfield chemical engineering. The corrosion and scale inhibitor has the following structural general formula: In the formula, x, y, and n are any integers from 1 to 10. The present invention also provides a preparation method of the corrosion and scale inhibitor, comprising the following steps: dissolving aconitic acid in water, then adding sodium p-styrenesulfonate and 3-aminopyrazole and dissolving them, and then heating to 65-85 °C and continuously adding an initiator to react to obtain the corrosion and scale inhibitor. The corrosion and scale inhibitor proposed by the present invention has excellent corrosion inhibition and scale inhibition performance.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemicals, and particularly relates to a corrosion and scale inhibitor and a preparation method thereof. Background Art

[0002] The reinjection of produced water in oilfields is an important way for water flooding development in oilfields. Simply treating the produced sewage and then reinjecting it into the formation can not only reduce environmental pollution but also save fresh water resources, which is an important way to improve the economic benefits of oilfields and ensure the sustainable development of oilfields. Although this can significantly improve the oil recovery rate, it also makes the fluid components more complex, prone to equipment scaling and corrosion problems, causing serious economic losses and even leading to production shutdown. In most areas of the oilfield, the produced fluid has a serious scaling tendency, which can lead to under-scale corrosion and even pipeline perforation.

[0003] Currently, the main methods to solve the problems of corrosion and scaling in the oilfield production process are to add chemical agents such as corrosion inhibitors and scale inhibitors. Due to the large differences in water quality and working conditions in different blocks, in some harsh environments such as high temperature, high salt, and high CO2, a single scale inhibitor or corrosion inhibitor is difficult to effectively inhibit the scaling and corrosion of oil pipes. Therefore, different types of corrosion inhibitors and scale inhibitors need to be compounded and used. However, the problem with compounding and using is that the physical and chemical properties of different chemical agents vary greatly. At the same time, injecting the scale inhibitor and the corrosion inhibitor may cause incompatibility between the two and result in the failure of the reagent. Adding them batch by batch will also make the injection process cumbersome. Therefore, the "scale prevention + corrosion prevention" integrated inhibitor has significant advantages. However, how to obtain a corrosion and scale inhibitor with excellent corrosion inhibition and scale inhibition performance is a problem that needs to be solved by the existing technology. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies, and provide a corrosion and scale inhibitor and a preparation method thereof, so as to solve the technical problem of how to obtain a corrosion and scale inhibitor with excellent corrosion inhibition and scale inhibition performance in the existing technology.

[0005] To achieve the above technical purpose, the technical solution of the present invention provides a corrosion and scale inhibitor with the following general structural formula:

[0006]

[0007] In the formula, x, y, and n are any integers from 1 to 10.

[0008] In addition, the present invention also provides a preparation method of the corrosion and scale inhibitor, including the following steps:

[0009] Dissolve aconitic acid in water, then add sodium p-styrenesulfonate and 3-aminopyrazole and dissolve them. Then, heat up to 65 - 85 °C and continue to add an initiator to react to obtain the corrosion and scale inhibitor.

[0010] In any embodiment, dissolving aconitic acid in water includes: mixing aconitic acid with water, and then heating to 50 - 55 °C and stirring until dissolved.

[0011] In any embodiment, the molar ratio of aconitic acid to sodium p-styrenesulfonate is (1 - 3):1.

[0012] In any embodiment, the molar ratio of aconitic acid to 3-aminopyrazole is (1 - 4):1.

[0013] In any embodiment, the addition amount of the initiator is 8% - 15% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole.

[0014] In any embodiment, the reaction time for continuously adding the initiator is 0.5 - 2 h.

[0015] In any embodiment, the addition method of the initiator is dropwise addition, and the time required to complete the dropwise addition is 1 - 2 h.

[0016] In any embodiment, the initiator is one or both of ammonium persulfate and ammonium ferrous sulfate.

[0017] In any embodiment, the molar ratio of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole is 4:2:1, the addition amount of the initiator is 10% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole, heating to 75 °C and continuing to add the initiator at 75 °C, and the reaction time is 1.5 h.

[0018] Compared with the prior art, the beneficial effects of the present invention include: The preparation method of the corrosion and scale inhibitor proposed by the present invention uses aconitic acid as a polymerization monomer, so that the polymer molecule has a large number of carboxylic acid groups. The carboxylic acid group is the most important group for inhibiting the formation of calcium scale. At the same time, the carboxyl group and the adjacent hydroxyl group cooperate to enhance the complexing effect on calcium ions, and at the same time increase the diffusivity and permeability of the molecule; introducing sodium p-styrenesulfonate and 3-aminopyrazole makes the polymer molecule contain phenyl and nitrogen-containing five-membered heterocycles, enhancing the adsorption ability of the polymer molecule on the metal surface and forming a protective layer to achieve a good corrosion inhibition effect. In addition, the amide group and phenyl group in the polymer molecule can improve the solubility of the polymer, enhance the stability and durability of the polymer molecule, so that the obtained corrosion and scale inhibitor has excellent corrosion inhibition and scale inhibition performance. Description of the Drawings

[0019] Figure 1 It is the infrared spectrogram of the corrosion and scale inhibitor prepared in Example 3 of the present invention. Detailed Embodiments

[0020] The "ranges" disclosed in this application are defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges defined in this way can include or exclude the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise specified, the numerical range "a-b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are fully listed herein, and "0-5" is only an abbreviated representation of these numerical combinations. In addition, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] Unless otherwise specified, the terms "comprising" and "including" mentioned in this application mean open-ended, and can also be closed-ended. For example, the said "comprising" and "including" can mean that other components not listed can also be included or contained, or can only include or contain the listed components.

[0022] Unless otherwise specified, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0023] This specific embodiment provides a corrosion and scale inhibitor with the following structural general formula:

[0024]

[0025] In the formula, x, y, and n are each any integer from 1 to 10.

[0026] The copolymer corrosion and scale inhibitor of the present invention introduces a large number of carboxyl groups, phenyl groups and nitrogen-containing five-membered heterocycles. The large π bond in the phenyl group forms a coordination bond and a feedback bond with the empty d orbital on the metal surface through charge transfer, thereby realizing the stable adsorption of the inhibitor molecules on the metal surface and effectively improving the corrosion inhibition performance. At the same time, the nitrogen-containing heterocycle can be adsorbed on the metal surface and form a stable chelate with it, and hydrogen bonds are formed between or within molecules to form a protective layer to protect the metal from being damaged by corrosive ions. Among them, the five-membered heterocyclic structure has multiple adsorption centers and has the characteristics of convenient use, low cost and high efficiency. At the same time, a large number of carboxyl groups can chelate with metal ions to form complexes, which are effective scale inhibition groups and play an important role in scale inhibition.

[0027] This specific embodiment also proposes a preparation method of the above corrosion and scale inhibitor, including the following steps:

[0028] Dissolve aconitic acid in water, then add sodium p-styrenesulfonate and 3-aminopyrazole and dissolve them, and then raise the temperature to 65-85 °C and continue to add an initiator to react for 0.5-2 h to obtain the corrosion and scale inhibitor; the molar ratio of aconitic acid to sodium p-styrenesulfonate is (1-3):1; the molar ratio of aconitic acid to 3-aminopyrazole is (1-4):1; the addition amount of the initiator is 8%-15% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole; the initiator is one or two of ammonium persulfate and ammonium ferrous sulfate.

[0029] In some embodiments, the step of dissolving aconitic acid in water includes: mixing aconitic acid with water, and then raising the temperature to 50-55 °C and stirring until dissolved.

[0030] In some embodiments, the addition method of the initiator is dropwise addition, and the time required to complete the dropwise addition is 1-2 h.

[0031] In some embodiments, the molar ratio of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole is 4:2:1, the addition amount of the initiator is 10% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole, raise the temperature to 75 °C and continue to add the initiator at 75 °C, and the reaction time is 1.5 h.

[0032] The present invention adopts a redox initiator system and obtains a terpolymer through aqueous solution free radical copolymerization. The reaction mechanism involved is:

[0033] During the reaction process, the carbon-carbon double bonds of aconitic acid and p-styrenesulfonic acid are broken, and then chain polymerization occurs. Ammonium persulfate and ammonium ferrous sulfate act as initiators to become active centers and undergo an addition reaction with the monomers. The amino group in 3-aminopyrazole undergoes an amidation reaction with the carboxylic acid group in aconitic acid. The reaction formula is as follows:

[0034]

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] In the present invention, terms such as "some embodiments", "this embodiment" and examples, etc. are involved, which describe subsets of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0037] If similar descriptions such as "first / second" appear in the application documents, the following description will be added. In the following description, the terms "first\second\third" involved are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence when permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0038] In this embodiment, the term "and / or" only describes the association relationship of associated objects, indicating that there can be three relationships. For example, object A and / or object B can represent: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0039] The following describes the embodiments of the present application. The embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial procurement.

[0040] Embodiment 1

[0041] This embodiment provides a preparation method of a corrosion and scale inhibitor, comprising the following steps:

[0042] Under air conditions, a certain amount of aconitic acid and pure water were added to a reactor. The temperature was raised to 55 °C, and after stirring evenly until completely dissolved, sodium p-styrenesulfonate and 3-aminopyrazole were added. The molar ratio of aconitic acid to sodium p-styrenesulfonate was 1:1, and the molar ratio of aconitic acid to 3-aminopyrazole was 1:1. After sodium p-styrenesulfonate and 3-aminopyrazole were completely dissolved, the temperature was raised to 70 °C, and ammonium persulfate as the initiator was added dropwise evenly and completed within 1 h. The addition amount of the initiator was 15% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole. The reaction temperature was controlled at 70 °C for 1 h. After the reaction ended, it was cooled to obtain the reaction product solution. The product was purified by dialysis to remove unreacted small molecule monomers, and the polymer corrosion and scale inhibitor was obtained after freeze-drying.

[0043] Example 2

[0044] This example provides a preparation method of a corrosion and scale inhibitor, including the following steps:

[0045] Under air conditions, a certain amount of aconitic acid and pure water were added to a reactor. The temperature was raised to 55 °C, and after stirring evenly until completely dissolved, sodium p-styrenesulfonate and 3-aminopyrazole were added. The molar ratio of aconitic acid to sodium p-styrenesulfonate was 2:1, and the molar ratio of aconitic acid to 3-aminopyrazole was 2:1. After sodium p-styrenesulfonate and 3-aminopyrazole were completely dissolved, the temperature was raised to 80 °C, and ammonium ferrous sulfate as the initiator was added dropwise evenly and completed within 1 h. The addition amount of the initiator was 12% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole. The reaction temperature was controlled at 80 °C for 1.5 h. After the reaction ended, it was cooled to obtain the reaction product solution. The product was purified by dialysis to remove unreacted small molecule monomers, and the polymer corrosion and scale inhibitor was obtained after freeze-drying.

[0046] Example 3

[0047] This example provides a preparation method of a corrosion and scale inhibitor, including the following steps:

[0048] Under air conditions, a certain amount of aconitic acid and pure water were added to a reactor. The temperature was raised to 55 °C, and after stirring evenly until completely dissolved, sodium p-styrenesulfonate and 3-aminopyrazole were added. The molar ratio of aconitic acid to sodium p-styrenesulfonate was 2:1, and the molar ratio of aconitic acid to 3-aminopyrazole was 4:1. After sodium p-styrenesulfonate and 3-aminopyrazole were completely dissolved, the temperature was raised to 75 °C, and ammonium ferrous sulfate as the initiator was added dropwise evenly and completed within 1 h. The addition amount of the initiator was 10% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole. The reaction temperature was controlled at 75 °C for 1.5 h. After the reaction ended, it was cooled to obtain the reaction product solution. The product was purified by dialysis to remove unreacted small molecule monomers, and the polymer corrosion and scale inhibitor was obtained after freeze-drying.

[0049] Figure 1 The infrared spectrum of the scale inhibitor prepared in this example. From Figure 1 it is found that there are characteristic absorption peaks at 3436.8 cm -1 , 2926.5 cm -1 , 1732.1 cm -1 , 1637.6 cm -1 , 1424.8 cm -1 , 1123.6 cm -1 , 1021.5 cm -1 , 685.2 cm -1 and 571.8 cm -1 . Among them, the absorption peaks at 3436.8 cm -1 and 1637.6 cm -1 are the stretching vibration absorption peaks of NH in the amide group and the stretching vibration absorption peak of C=O respectively. The absorption peak at 2926.5 cm -1 is the stretching vibration absorption peak of methylene. The vibrations at 1732.1 cm -1 and 1123.6 cm -1 are caused by the stretching vibration peaks of C=O and C-O in the carboxylic acid group respectively. The absorption peak at 1429.8 cm -1 is the characteristic absorption peak of C-N stretching vibration. The characteristic absorption peaks at 685.2 cm -1 and 571.8 cm -1 are caused by C-S stretching vibration. At the same time, no C=C absorption peak at 1620 - 1640 cm -1 is found in the infrared spectrum, indicating that the monomers have copolymerized to obtain the target product, the corrosion and scale inhibitor.

[0050] Example 4

[0051] This example proposes a preparation method of a corrosion and scale inhibitor, including the following steps:

[0052] Under air conditions, a certain amount of aconitic acid and pure water are added to the reactor, the temperature is raised to 55 °C, and it is stirred evenly until completely dissolved, then sodium p-styrenesulfonate and 3-aminopyrazole are added. The molar ratio of aconitic acid to sodium p-styrenesulfonate is 2:1, and the molar ratio of aconitic acid to 3-aminopyrazole is 4:1. After sodium p-styrenesulfonate and 3-aminopyrazole are completely dissolved, the temperature is raised to 85 °C, and ammonium persulfate as the initiator is added dropwise evenly and finished within 1 h. The addition amount of the initiator is 8% of the total mass of aconitic acid, sodium p-styrenesulfonate and 3-aminopyrazole. The reaction temperature is controlled at 85 °C for 1 h. After the reaction, it is cooled to obtain the reaction product solution. The product is purified by dialysis to remove unreacted small molecule monomers, and the polymer corrosion and scale inhibitor is obtained after freeze-drying.

[0053] Comparative Example 1

[0054] This comparative example presents a preparation method of a corrosion and scale inhibitor, which is only different from Example 3 in that 3-aminopyrazole is not added, and it includes the following steps:

[0055] Under air conditions, a certain amount of aconitic acid and pure water are added to a reactor, the temperature is raised to 55 °C, and after stirring evenly until completely dissolved, sodium p-styrenesulfonate is added. The dosage of aconitic acid is the same as that in Example 3, and the dosage of sodium p-styrenesulfonate is the total dosage of sodium p-styrenesulfonate and 3-aminopyrazole in Example 3. After sodium p-styrenesulfonate is completely dissolved, the temperature is raised to 75 °C, and ammonium ferrous sulfate as the initiator is added dropwise evenly and completed within 1 h. The addition amount of the initiator is 10% of the total mass of aconitic acid and sodium p-styrenesulfonate. Control the reaction temperature at 75 °C, react for 1.5 h, cool after the reaction ends to obtain a reaction product solution. The product is purified by dialysis to remove unreacted small molecule monomers, and a polymeric corrosion and scale inhibitor is obtained after freeze-drying.

[0056] Comparative Example 2

[0057] This comparative example presents a preparation method of a corrosion and scale inhibitor, which is only different from Example 3 in that sodium p-styrenesulfonate is not added, and it includes the following steps:

[0058] Under air conditions, a certain amount of aconitic acid and pure water are added to a reactor, the temperature is raised to 55 °C, and after stirring evenly until completely dissolved, 3-aminopyrazole is added. The dosage of aconitic acid is the same as that in Example 3, and the dosage of 3-aminopyrazole is the total dosage of sodium p-styrenesulfonate and 3-aminopyrazole in Example 3. After 3-aminopyrazole is completely dissolved, the temperature is raised to 75 °C, and ammonium ferrous sulfate as the initiator is added dropwise evenly and completed within 1 h. The addition amount of the initiator is 10% of the total mass of aconitic acid and 3-aminopyrazole. Control the reaction temperature at 75 °C, react for 1.5 h, cool after the reaction ends to obtain a reaction product solution. The product is purified by dialysis to remove unreacted small molecule monomers, and a polymeric corrosion and scale inhibitor is obtained after freeze-drying.

[0059] Corrosion inhibition performance test

[0060] The medium used for the test is the produced water sample from a certain block in Changqing Oilfield. The test method is the rotary coupon corrosion test, and the material used for the test is carbon steel. Specifically:

[0061] Use a vernier caliper to measure the size of the coupon, accurate to 0.02 mm, and calculate the area of the coupon. Wipe the coupon clean with filter paper, put it into a vessel containing petroleum ether with a boiling range of 60 - 90 °C, remove the surface grease with absorbent cotton, then soak it in absolute ethanol for 5 min for further degreasing and dehydration. Take out the coupon, place it on filter paper, blow it dry with cold air, wrap the coupon with filter paper again, store it in a desiccator, and weigh it accurately to 0.01 mg after placing it for 1 h.

[0062] The corrosion inhibitor was added to the experimental container, and the content of the corrosion inhibitor in the water sample was 100 mg / L. The amount of the water sample used was 20 mL for every 1 cm 2 of the surface area of the test piece (the test piece has an area of 50 mm * 13 mm * 1.5 mm). The experimental container was purged with nitrogen to remove air, and then the oilfield water was introduced through a rubber tube. At the same time, a blank sample without the corrosion inhibitor was prepared. It was placed in an incubator at a temperature of 70 °C for a period of 7 days. The test results were recorded in Table 1.

[0063] Table 1 Test Results of the Corrosion Inhibition Performance of the Corrosion and Scale Inhibitor

[0064]

[0065] Note: The mass loss of the medium blank Δm0 = 0.0375 g; the annual average corrosion rate is 0.167 mm / year.

[0066] As can be seen from Table 1, the corrosion and scale inhibitor provided by the present invention has good corrosion inhibition performance. When the dosage is 100 mg / L, the corrosion inhibition efficiency can reach 82.93%, and the corrosion rate can be as low as 0.029 mm / year.

[0067] Performance Test of Inhibiting Calcium Carbonate Scale

[0068] The static scale inhibition evaluation method was adopted to test the performance of the polymer prepared in the examples in inhibiting calcium carbonate scale, and the test results were recorded in Table 2.

[0069] Accurately weigh 0.50 g of the scale inhibitor, dissolve it with a small amount of pure water, and transfer it to a 250 mL volumetric flask and dilute it to the mark to obtain the scale inhibitor solution. Take 200 mL of pure water in a 250 mL volumetric flask, add the pre-prepared CaCl2 solution to prepare a calcium chloride solution with a Ca 2+ content of 96.00 mg·L -1 . Accurately add 3.75 ml of the scale inhibitor solution to the calcium chloride solution, let it stand for 10 min, and then add the pre-prepared Na2CO3 solution while shaking to make the CO3 2- content 150.72 mg·L -1 . Then dilute it to the mark with pure water, transfer it to a ground glass conical flask, and place it in a water bath at 50 °C ± 1 °C for half an hour of constant temperature and then let it stand for 16 h.

[0070] After the reaction is completed, cool the solution to room temperature and filter it with quantitative filter paper. Titrate the filtrate of CaCO3 with an ethylenediaminetetraacetic acid (EDTA) standard solution to determine the concentration of Ca 2+ , and conduct a blank test at the same time. Calculate the scale inhibition rate according to the following formula:

[0071]

[0072] where η (100%) is the scale inhibition rate, V blank2 is the volume of EDTA consumed by all calcium ions in the solution; V blank1 is the volume of EDTA consumed by calcium ions in the solution without the addition of scale inhibitor; V final is the volume of EDTA consumed by calcium ions in the solution after the addition of scale inhibitor.

[0073] Table 2 Test results of scale inhibition performance of corrosion and scale inhibitor

[0074] Serial number Scale inhibitor dosage (mg / L) Calcium carbonate scale inhibition rate (%) Example 1 30 88.2 Example 2 30 90.2 Example 3 30 93.7 Example 4 30 87.7 Comparative example 1 30 55.5 Comparative example 2 30 45.8

[0075] As can be seen from Table 2, the corrosion and scale inhibitor proposed by the present invention has good inhibition performance on calcium carbonate, and a scale inhibition efficiency of 93.7% can be achieved with 30 mg / L of scale inhibitor.

[0076] The specific embodiments of the present invention described above do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A corrosion and scale inhibitor, characterized in that, It has the following structural general formula: In the formula, x, y, and n are each any integer from 1 to 10.

2. A preparation method of a corrosion and scale inhibitor, characterized in that, It includes the following steps: Dissolve aconitic acid in water, then add sodium p-styrenesulfonate and 3-aminopyrazole and dissolve them. Then raise the temperature to 65 - 85 °C and continue to add an initiator to react to obtain the corrosion and scale inhibitor; the molar ratio of aconitic acid to sodium p-styrenesulfonate is (1 - 3):1; the molar ratio of aconitic acid to 3-aminopyrazole is (1 - 4):

1.

3. The preparation method of the corrosion and scale inhibitor according to claim 2, wherein, The step of dissolving aconitic acid in water includes: mixing aconitic acid with water, then raising the temperature to 50 - 55 °C and stirring until dissolved.

4. The preparation method of the corrosion and scale inhibitor according to claim 2, wherein, The addition amount of the initiator is 8% - 15% of the total mass of aconitic acid, sodium p-styrenesulfonate, and 3-aminopyrazole.

5. The preparation method of the corrosion and scale inhibitor according to claim 2, characterized in that, The reaction time for continuously adding the initiator is 0.5 - 2 h.

6. The preparation method of the corrosion and scale inhibitor according to claim 2, wherein The addition method of the initiator is dropwise addition, and the time required to complete the dropwise addition is 1 - 2 h.

7. The preparation method of the corrosion and scale inhibitor according to claim 2, characterized in that The initiator is ammonium persulfate.

8. The preparation method of the corrosion and scale inhibitor according to claim 2, characterized in that, The molar ratio of aconitic acid, sodium p-styrenesulfonate, and 3-aminopyrazole is 4:2:1, the addition amount of the initiator is 10% of the total mass of aconitic acid, sodium p-styrenesulfonate, and 3-aminopyrazole, raise the temperature to 75 °C and continue to add the initiator, and the reaction time is 1.5 h.

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