A green scale inhibitor for barium sulfate and its preparation method

Abstract

This invention belongs to the field of water treatment technology, specifically disclosing a green scale inhibitor for barium sulfate and its preparation method. The scale inhibitor is a copolymer formed by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate under alkaline conditions, aconitic acid, and sodium lignosulfonate graft copolymerization, wherein the mass ratio of polysuccinimide / hydroxyethyl methacrylate / aconitic acid / sodium lignosulfonate is 2:4:(1-6):(1-4). The scale inhibitor of this invention is a composite copolymer formed by the polymerization and grafting of the esterified product of polysuccinimide / hydroxyethyl methacrylate, aconitic acid, and sodium lignosulfonate. It simultaneously possesses carboxyl, hydroxyl, amino, and sulfonic acid groups, which can strongly interact with key ions or sites in the BaSO4 crystal growth process, preventing the normal growth and aggregation of BaSO4 crystals, thereby effectively inhibiting the formation of BaSO4 scale.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a green scale inhibitor for barium sulfate and its preparation method. Background Technology

[0002] In many areas of industrial production, such as oil extraction, chemical production, and industrial circulating water systems, the formation of barium sulfate scale is a common and challenging problem. For example, in oil extraction, barium ions and sulfate ions in formation water can react under specific conditions to form barium sulfate precipitates, which gradually accumulate on the surfaces of pipes and equipment. Over time, this leads to a reduction in the inner diameter of pipes, hindering fluid transport, increasing pump pressure, and raising energy consumption. In heat exchange equipment, barium sulfate scale reduces heat transfer efficiency, affecting temperature control in the production process, thereby reducing production efficiency and product quality. In industrial circulating water systems, the accumulation of barium sulfate scale can also trigger secondary problems such as microbial growth, accelerating equipment corrosion, shortening equipment lifespan, increasing maintenance costs and downtime, and seriously affecting production continuity and economic benefits.

[0003] Typically, industrial applications use scale inhibitors specifically designed for barium sulfate scale to address this problem. However, traditional barium sulfate scale inhibitors often have various drawbacks. For example, while some phosphorus-containing scale inhibitors offer some scale inhibition, they can lead to eutrophication of water bodies, causing environmental problems such as excessive algae growth, and are subject to increasingly stringent environmental regulations. Some polymer scale inhibitors are costly and have complex synthesis processes, increasing the cost and production difficulty for enterprises, which hinders large-scale application. Furthermore, some traditional scale inhibitors exhibit unstable scale inhibition performance under complex operating conditions such as high temperature and high hardness, making it difficult to meet the diverse practical needs of industrial production and effectively solve the various problems caused by barium sulfate scale, thus limiting the efficient operation and sustainable development of industrial production.

[0004] Therefore, there is an urgent need for a stable and effective scale inhibitor for barium sulfate. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a scale inhibitor that can effectively suppress the formation of barium sulfate scale, while also meeting the requirements of green environmental protection, i.e., reducing negative environmental impacts, and is cost-effective, making it feasible and competitive in industrial applications. This solves many problems caused by barium sulfate scale in industrial production and ensures efficient and stable operation of the production process.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] According to a first aspect of the present invention, the present invention first provides a green scale inhibitor for barium sulfate, the scale inhibitor being a copolymer formed by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate under alkaline conditions, aconitic acid and sodium lignosulfonate graft copolymerization, wherein the mass ratio of polysuccinimide / hydroxyethyl methacrylate / aconitic acid / sodium lignosulfonate is 2:4:(1-6):(1-4).

[0008] Preferably, the molar ratio of polysuccinimide to hydroxyethyl methacrylate in the product generated by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate under alkaline conditions is 1:2.

[0009] Preferably, the molar ratio of the product generated by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate under alkaline conditions, aconitic acid, and sodium lignosulfonate is 6:2:(1-3).

[0010] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned scale inhibitor, comprising the following steps:

[0011] S1. Polysuccinimide and hydroxyethyl methacrylate are mixed, an alkaline solution is added to control the pH to 9-10, and an esterification reaction is carried out under heating conditions to obtain product A;

[0012] S2. The product A, aconitic acid solution, sodium lignosulfonate solution, and initiator solution are subjected to a graft polymerization reaction under heating conditions to obtain the final product.

[0013] Preferably, in step S1, the alkaline solution is either sodium hydroxide solution or potassium hydroxide solution, the heating temperature is 55-60°C, and the esterification reaction time is 3-4 hours.

[0014] Preferably, in step S2, product A is heated to 85-90°C before the graft polymerization reaction, and the graft polymerization reaction conditions are 90°C for 3-4 hours.

[0015] Preferably, the initiator solution is an ammonium persulfate solution.

[0016] Preferably, the method further includes step S3: precipitating solids from the product solution obtained in step S2 with methanol, and filtering, washing, and vacuum drying the solids.

[0017] According to a third aspect of the invention, the invention also provides the application of the above-mentioned scale inhibitor in scale inhibition in water bodies.

[0018] Preferably, the water body is the water body in the oilfield development process, and the concentration of scale inhibitor in the water body is 10-30 mg / L.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The scale inhibitor of the present invention is a composite copolymer formed by polymerization and grafting of the product of polysuccinimide / hydroxyethyl methacrylate esterification, aconitic acid, and sodium lignosulfonate. It simultaneously possesses carboxyl, hydroxyl, amino, and sulfonic acid groups, which can strongly interact with key ions or sites in the BaSO4 crystal growth process, preventing the normal growth and aggregation of BaSO4 crystals, thereby effectively inhibiting the formation of BaSO4 scale. Aconitic acid has multiple active groups such as carboxyl groups, and sodium lignosulfonate has a complex aromatic structure and sulfonic acid groups. These synergistic effects with the reaction product of polysuccinimide and hydroxyethyl methacrylate enhance the affinity and inhibition ability for BaSO4, making it excellent in inhibiting BaSO4 scale formation.

[0021] 2. The scale inhibitor of the present invention has a great advantage in terms of raw materials. First, polysuccinimide can be obtained from renewable resources, and sodium lignosulfonate is an industrial by-product, which can be reused. Moreover, the synthesis reaction can improve the atom utilization rate. Second, in terms of environmental impact, there is no phosphorus emission, which avoids eutrophication of water bodies. The synthesis adopts a green process, which reduces pollutants and is biodegradable.

[0022] 3. The preparation process of the present invention can improve the operating efficiency of industrial equipment, reduce costs, promote technological innovation, drive industrial development, comply with environmental protection policies, and ensure the sustainable operation of enterprises in terms of economic and social benefits. Attached Figure Description

[0023] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings;

[0024] Figure 1 The infrared spectrum of the PSI-HEMA copolymer prepared in this invention;

[0025] Figure 2 The infrared spectrum of the prepared PSI-HEMA-ANAN-SL copolymer is shown. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention provides a green scale inhibitor with high BaSO4 scale inhibition rate. The scale inhibitor is a copolymer formed by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate under alkaline conditions (as shown in Formula 1), and by graft copolymerization of aconitic acid and sodium lignosulfonate (as shown in Formula 2). The mass ratio of polysuccinimide, hydroxyethyl methacrylate, aconitic acid, and sodium lignosulfonate is 2:4:(1-6):(1-4):

[0028]

[0029]

[0030] In some specific embodiments, the mass ratio of polysuccinimide, hydroxyethyl methacrylate, aconitine, and sodium lignosulfonate is preferably 2:4:1:(1-2.67), and more preferably 2:4:1:2.

[0031] In some specific implementations, in formula (1), x and n represent the molar number of polysuccinimide and hydroxyethyl methacrylate, respectively, and x:n = 1:2.

[0032] This invention also provides a method for preparing the above-mentioned scale inhibitor, comprising the following steps:

[0033] S1. Polysuccinimide and hydroxyethyl methacrylate are mixed, an alkaline solution is added to control the pH to 9-10, and an esterification reaction is carried out under heating conditions to obtain product A;

[0034] S2. The product A, aconitic acid solution, sodium lignosulfonate solution, and initiator solution are subjected to a graft polymerization reaction under heating conditions to obtain the final product.

[0035] In some specific embodiments, in step S1, the alkaline solution is either sodium hydroxide solution or potassium hydroxide solution, the heating temperature is 55-60°C, and the esterification reaction time is 3-4 hours.

[0036] In some specific embodiments, in step S2, product A is heated to 85-90°C before the graft polymerization reaction, and the graft polymerization reaction is carried out at 90°C for 3-4 hours.

[0037] In some specific embodiments, the initiator solution is an ammonium persulfate solution.

[0038] In some specific embodiments, step S3 is also included: precipitating solids from the product solution obtained in step S2 with methanol, and filtering, washing, and vacuum drying the solids.

[0039] The scale inhibitor provided in this invention comprises a specific structure resulting from the reaction of polysuccinimide and hydroxyethyl methacrylate. Polysuccinimide contains imide groups; hydroxyethyl methacrylate contains hydroxyl and ester groups. Both can participate in the interaction with BaSO4 and can act as dispersants or surfactants to inhibit BaSO4 growth. The imide, hydroxyl, and ester groups in the product interact with BaSO4, exhibiting affinity. The product may also form an adsorption layer on the surface of BaSO4 crystals, interfering with crystal growth and aggregation, thereby inhibiting BaSO4 growth. The specific reaction process is as follows:

[0040]

[0041] In a specific embodiment, in step S2, product A from S1 is grafted with aconitine and sodium lignin sulfonate in the presence of ammonium persulfate as an initiator. The reaction formula is as follows:

[0042]

[0043] Specifically, the following steps are included:

[0044] Prepare aconitic acid solution, sodium lignosulfonate solution, and ammonium persulfate solution as the initiator, respectively.

[0045] After heating product A from step S1 to 85-90°C, aconitic acid solution, sodium lignosulfonate solution, and ammonium persulfate solution (an initiator) are added to product A, and the mixture is reacted at 90°C for 3-4 hours to obtain a green scale inhibitor.

[0046] In some specific embodiments, the initiator can be a commonly used initiator known in the polymer field, including but not limited to ammonium persulfate. The amount of initiator used is 2-5% of the total mass of product A, aconitic acid, and sodium lignosulfonate monomers.

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below with reference to the accompanying drawings.

[0048] Example 1

[0049] A method for preparing a green scale inhibitor with high BaSO4 scale inhibition rate includes the following steps:

[0050] S1. Preparation of polysuccinimide / hydroxyethyl methacrylate (PSI-HEMA) polymer

[0051] Polysuccinimide and deionized water were added to a three-necked flask equipped with a thermometer, a reflux condenser, and a stirrer to obtain a polysuccinimide suspension, wherein the mass-to-volume ratio of polysuccinimide to deionized water was 1:10. Stirring was started, and the temperature was raised to 55-60°C. During this process, hydroxyethyl methacrylate was added, wherein the mass-to-volume ratio of hydroxyethyl methacrylate to deionized water was 1:5. Meanwhile, 10% sodium hydroxide solution was continuously added dropwise to adjust the pH of the reaction system to 9-10, and the reaction was carried out for 3-4 hours. After the reaction was completed, methanol was added for purification to obtain product A (PSI-HEMA) polymer.

[0052] S2. Preparation of (PSI-HEMA-ANA-SL) copolymer scale inhibitor

[0053] Weigh the following components according to percentages: In step S1, we obtain (PSI-HEMA) polymer, 20% aconitic acid, 5% sodium lignosulfonate, and 5% ammonium persulfate as initiator. The sum of the mass percentages of each component is 100%.

[0054] The obtained product A (PSI-HEMA) was placed in a three-necked flask, sodium lignosulfonate and deionized water were added, and the temperature was raised to 85-90°C. During this process, aconitic acid solution and initiator ammonium persulfate solution were continuously added dropwise (0.5-1 h), and the reaction lasted for 3-4 h. After the reaction was completed, an appropriate amount was dialyzed with methanol, and finally dried in a drying oven for 24 h to obtain a pale yellow polymer, which is the (PSI-HEMA-ANA-SL) copolymer scale inhibitor of the present invention. The mass ratio of polysuccinimide, hydroxyethyl methacrylate, aconitic acid and sodium lignosulfonate is 2:4:6:1.

[0055] Example 2

[0056] A method for preparing a green scale inhibitor with high BaSO4 scale inhibition rate includes the following steps:

[0057] S1. Preparation of polysuccinimide / hydroxyethyl methacrylate (PSI-HEMA) polymer

[0058] Polysuccinimide and deionized water were added to a three-necked flask equipped with a thermometer, a reflux condenser, and a stirrer to obtain a polysuccinimide suspension, wherein the mass-to-volume ratio of polysuccinimide to deionized water was 1:10. Stirring was started, and the temperature was raised to 55-60°C. During this process, hydroxyethyl methacrylate was added, wherein the mass-to-volume ratio of hydroxyethyl methacrylate to deionized water was 1:5. Meanwhile, 10% sodium hydroxide solution was continuously added dropwise to adjust the pH of the reaction system to 9-10, and the reaction was carried out for 3-4 hours. After the reaction was completed, methanol was added for purification to obtain product A (PSI-HEMA) polymer.

[0059] S2. Preparation of (PSI-HEMA-ANA-SL) copolymer scale inhibitor

[0060] Weigh the following components according to percentages: In step S1, we obtain (PSI-HEMA) polymer, 5% aconitic acid, 10% sodium lignosulfonate, and 3% ammonium persulfate as initiator. The sum of the mass percentages of each component is 100%.

[0061] The obtained product A (PSI-HEMA) was placed in a three-necked flask, and sodium lignosulfonate and deionized water were added. The temperature was raised to 85-90°C. During this process, aconitic acid solution and ammonium persulfate initiator solution were continuously added dropwise (0.5-1 h), and the reaction lasted for 3-4 h. After the reaction was completed, an appropriate amount was dialyzed with methanol, and finally dried in a drying oven for 24 h to obtain a pale yellow polymer, which is the (PSI-HEMA-ANA-SL) copolymer scale inhibitor of the present invention. The mass ratio of polysuccinimide, hydroxyethyl methacrylate, aconitic acid, and sodium lignosulfonate is 2:4:1:2.

[0062] Example 3

[0063] A method for preparing a green scale inhibitor with high BaSO4 scale inhibition rate includes the following steps:

[0064] S1. Preparation of polysuccinimide / hydroxyethyl methacrylate (PSI-HEMA) polymer

[0065] Polysuccinimide and deionized water were added to a three-necked flask equipped with a thermometer, a reflux condenser, and a stirrer to obtain a polysuccinimide suspension, wherein the mass-to-volume ratio of polysuccinimide to deionized water was 1:10. Stirring was started, and the temperature was raised to 55-60°C. During this process, hydroxyethyl methacrylate was added, wherein the mass-to-volume ratio of hydroxyethyl methacrylate to deionized water was 1:5. Meanwhile, 10% sodium hydroxide solution was continuously added dropwise to adjust the pH of the reaction system to 9-10, and the reaction was carried out for 3-4 hours. After the reaction was completed, methanol was added for purification to obtain product A (PSI-HEMA) polymer.

[0066] S2. Preparation of (PSI-HEMA-ANA-SL) copolymer scale inhibitor

[0067] Weigh the following components according to percentages: In step S1, the following are obtained: (PSI-HEMA) polymer, aconitine 5%, sodium lignosulfonate 10%, sodium bisulfite 1%, and initiator ammonium persulfate 3%, with the sum of the mass percentages of each component being 100%.

[0068] The obtained product A (PSI-HEMA) was placed in a three-necked flask, and sodium lignosulfonate, sodium bisulfite, and deionized water were added. The temperature was raised to 85–90°C. During this process, aconitic acid solution and ammonium persulfate initiator solution were continuously added dropwise (0.5–1 h), and the reaction lasted for 3–4 h. After the reaction was completed, an appropriate amount was dialyzed with methanol, and finally dried in a drying oven for 24 h to obtain a pale yellow polymer, which is the (PSI-HEMA-ANA-SL) copolymer scale inhibitor of the present invention. The mass ratio of polysuccinimide, hydroxyethyl methacrylate, aconitic acid, and sodium lignosulfonate was 2:4:1:2.

[0069] Control group 1

[0070] Preparation of (HEMA-ANA-SL) copolymer scale inhibitor

[0071] Weigh the following components according to percentages: 10% hydroxyethyl methacrylate, 5% aconitic acid, 10% sodium lignosulfonate, and 3% ammonium persulfate as initiator. The sum of the mass percentages of each component is 100%.

[0072] Weigh out hydroxyethyl methacrylate, sodium lignosulfonate, and deionized water, and heat to 85–90°C. During this process, continuously add aconitic acid solution and ammonium persulfate solution (initiator) dropwise (0.5–1 h), and continue the reaction for 3–4 h. After the reaction is complete, take an appropriate amount and dialyze it with methanol. Finally, dry in a drying oven for 24 h to obtain the (HEMA-ANA-SL) copolymer. The mass ratio of hydroxyethyl methacrylate, aconitic acid, and sodium lignosulfonate is 4:1:2.

[0073] Control group 2

[0074] Polysuccinimide and hydroxyethyl methacrylate were mixed, and an alkaline solution was added to control the pH to 9-10. The esterification reaction was carried out under heating conditions. The mass ratio of polysuccinimide to hydroxyethyl methacrylate was 1:2, and product A was obtained.

[0075] Figure 1 The infrared spectrum of the PSI-HEMA copolymer prepared in this invention is shown below. Figure 1 The middle curve is shown at 3417.5cm. -1 The absorption peak is a combination of the stretching vibration of the amide group (NH bond) and the stretching vibration of the carboxyl group (OH bond), at 2970 cm⁻¹. -1 The absorption peak is due to the stretching vibration of the methyl CH bond and is 2932.8 cm⁻¹. -1 The absorption peak is due to the stretching vibration of the methylene CH bond. Both polysuccinimide and hydroxyethyl methacrylate contain saturated carbon atoms, and the peak is 1624.1 cm⁻¹. -1 This absorption peak is the stretching vibration peak of C=C, at 1557 cm⁻¹. -1The peak at 1418.2 cm⁻¹ is a combined absorption peak resulting from the bending vibration of the NH bond in the amide group and the stretching vibration of the CN bond. This is because polysuccinimide contains an amide structure. -1 The absorption peak at 1243.3 cm⁻¹ represents the bending vibration of the methylene group, further confirming the presence of a saturated alkyl structure in the product. -1 The absorption peak corresponds to the stretching vibration of COC, which in turn corresponds to the vibration of the ester bond, indicating that the esterification reaction may have resulted in the formation of ester bonds. This demonstrates the successful preparation of the PSI-HEMA polymer, and the presence of functional groups such as carboxyl, amide, ester, and double bonds in the polymer molecule indicates its scale inhibition activity.

[0076] Figure 2 The infrared spectrum of the prepared PSI-HEMA-ANAN-SL copolymer is shown at 3388.9 cm⁻¹. -1 The absorption peak near this wavenumber is usually attributed to the stretching vibration of OH, 3074.2 cm⁻¹. -1 and 2946.5cm -1 These two absorption peaks near the wavenumbers correspond to the stretching vibration of CH. 3074.2 cm⁻¹ -1 The nearby absorption peak is related to unsaturated CH (CH on the double bond), while 2946.5 cm⁻¹ -1 The nearby absorption peak corresponds to the stretching vibration of saturated CH (such as CH on alkyl groups), 1713 cm⁻¹. -1 The absorption peak at this wavenumber is attributed to the stretching vibration of C=O, possibly due to the vibrational absorption of the carbonyl or ester group in polysuccinimide (generated by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate) or the carbonyl group in aconitic acid. 1658.3 cm⁻¹ -1 This wavenumber is related to the C=C stretching vibration and originates from the carbon-carbon double bond in aconitine, or from the C=C stretching vibration absorption peak of the aromatic ring. Lignin has an aromatic ring structure, 1398.3 cm⁻¹ -1 The absorption peak near this wavenumber is related to the bending vibration of CH, especially the symmetric bending vibration of methyl (-CH3), at 1122.4 cm⁻¹. -1 This wavenumber corresponds to the stretching vibration absorption peak of S=O, which is the vibrational absorption of ether bonds and other components in the sodium lignosulfonate structure, at 614 cm⁻¹. -1 The peaks are CS stretching absorption vibrations. These all indicate the presence of polymerized, grafted PSI-HEMA-ANA-SL copolymer scale inhibitors.

[0077] Performance testing:

[0078] The methods for determining the scale inhibition rate of barium sulfate in Examples 1-3 and Control Groups 1-2 are as follows:

[0079] Accurately weigh 0.50g of scale inhibitor, dissolve it in a small amount of deionized water, transfer it to a 250mL volumetric flask, and dilute to the mark to obtain the scale inhibitor solution.

[0080] Barium sulfate: Take 200 mL of deionized water into a 250 mL volumetric flask, add the pre-prepared BaCl2 solution, and let Ba... 2+ The content is 2.8 mg·mL -1 In three sets of experiments, 1.25 mL, 2.50 mL, and 3.75 mL of scale inhibitor solution were accurately added, respectively. After standing for 10 minutes, a pre-prepared Na₂SO₄ solution was added while shaking, so that the SO₄²⁻ solution... 2- The content is 2.06 mg·mL -1 Dilute with deionized water to the mark, pour into a ground glass joint Erlenmeyer flask, place in a water bath at 50℃±1℃ for half an hour, and let stand for 24 hours.

[0081] After the reaction was complete, the solution was cooled to room temperature and filtered using quantitative filter paper. The filtrate of BaSO4 was titrated with ethylenediaminetetraacetic acid (EDTA) standard solution to determine Ba. 2+ The concentration of scale is shown in Table 1.

[0082] As shown in Table 1, the scale inhibitors prepared in Examples 1 to 3 have different scale inhibition efficiencies due to differences in monomer ratios and preparation conditions.

[0083] Table 1 Static Tests of Barium Sulfate

[0084]

[0085]

[0086] As shown in Table 1, the scale inhibitor provided by the present invention has good inhibition performance against barium sulfate, and a scale inhibition efficiency of 90% can be achieved with a scale inhibitor concentration of 30 mg / L.

[0087] Application Test 1

[0088] Water injected from an oil well in Jianghan Oilfield was collected and stored in five 100ml test tubes. The scale inhibitors from Examples 1-3 and Control Groups 1-2 were added to test tubes 1-5 respectively, with a concentration of 30mg / L. The results are shown in Table 2.

[0089] Table 2 Application data of Examples 1-3 and Control Groups 1-2

[0090] project Appearance Anti-expansion rate % Actual scale inhibition rate % Test tube 1 No obvious stratification after mixing 29.4 81.2 test tube 2 No obvious stratification after mixing 32.1 90.0 test tube 3 No obvious stratification after mixing 30.8 85.4 test tube 4 Poor mixing properties, turbid state 21.7 33.5 5 test tubes Poor mixing properties, turbid state 17.2 14.9

[0091] Application Test 2

[0092] The barium sulfate scale inhibitor prepared in Example 2 was applied to an oil well in the Jianghan Oilfield at a concentration of 30 mg / L. In February 2024, a fixed online injection booster was installed at the well site to increase the pressure, and the injection water met the requirements. From April to May 2024, the pressure continued to rise. From June 2024, the above-mentioned concentration of barium sulfate strontium scale inhibitor was continuously added. After three months of addition, by September 2024, the oil pressure had decreased by 1.3 MPa. After stopping the addition of the scale inhibitor, the oil pressure returned to the level before the addition in December 2024. The scale inhibitor was added again in January 2025, and the pressure has remained stable to date, as shown in Table 3.

[0093] Table 3 Pressure data of a certain oil well in Jianghan Oilfield for the past year, 2024-2025

[0094] Time period Pressure change relative to initial value (MPa) 2024.2 -- 2024.4 +0.45 2024.5 +0.65 2024.6 -0.2 2024.9 -1.5 2024.12 0 2025.1-present -1.35

[0095] In summary, the scale inhibitor provided by this invention, through monomer design and grafting process optimization, integrates the biodegradability of PSI, the strong chelating ability of aconitic acid, and the dispersibility of SL to form a multifunctional synergistic system, thereby significantly improving scale inhibition performance and achieving a high-efficiency scale inhibition rate of 90%, far exceeding the effect of sodium lignosulfonate alone. This result aligns with the trend of modern water treatment agents developing towards "multi-component grafting, green and efficient" technologies.

[0096] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0097] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A green scale inhibitor for barium sulfate, characterized in that, The scale inhibitor is a copolymer formed by the esterification reaction of polysuccinimide and hydroxyethyl methacrylate under alkaline conditions, graft copolymerization of aconitic acid and sodium lignosulfonate, wherein the mass ratio of polysuccinimide, hydroxyethyl methacrylate, aconitic acid and sodium lignosulfonate is 2:4:(1-6):(1~4).

2. A method for preparing the scale inhibitor as described in claim 1, characterized in that, Includes the following steps: S1. Polysuccinimide and hydroxyethyl methacrylate are mixed, an alkaline solution is added to control the pH to 9-10, and an esterification reaction is carried out under heating conditions to obtain product A; S2. The product A, aconitic acid solution, sodium lignosulfonate solution, and initiator solution are subjected to a graft polymerization reaction under heating conditions to obtain the final product.

3. The preparation method according to claim 2, characterized in that, In step S1, the alkaline solution is either sodium hydroxide solution or potassium hydroxide solution, the heating temperature is 55~60℃, and the reaction time of the esterification reaction is 3~4h.

4. The preparation method according to claim 2, characterized in that, In step S2, product A is heated to 85-90°C before the graft polymerization reaction, and the reaction conditions for graft polymerization are 3-4 hours at 90°C.

5. The preparation method according to claim 2, characterized in that, The initiator solution is an ammonium persulfate solution.

6. The preparation method according to claim 2, characterized in that, It also includes step S3: precipitating solids from the product solution obtained in step S2 with methanol, and filtering, washing, and vacuum drying the solids.

7. The application of the scale inhibitor as described in claim 1 in scale inhibition in water bodies.

8. The application according to claim 7, characterized in that, The water body is the water body in the oilfield development process, and the concentration of scale inhibitor in the water body is 10~30mg / L.

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