Preparation method of corrosion and scale inhibitor

Abstract

This application relates to the technical field of scale inhibitors, specifically disclosing a method for preparing a corrosion and scale inhibitor. The method includes the following steps: dissolving modified polyaspartic acid in hydrotreated diesel oil, adding an antioxidant, and mixing thoroughly to obtain solution A; dissolving hydrolyzed polymaleic anhydride in hydrotreated diesel oil to obtain solution B; mixing an imidazoline oleyl polyamine corrosion inhibitor and 2-amino-5-methyl-4-phenylthiazole thoroughly to obtain mixture C; adding sodium dodecylbenzenesulfonate to hydrotreated diesel oil, then adding nano-titanium dioxide and nano-zinc oxide, and mixing thoroughly to obtain dispersion D; dissolving the dispersant in hydrotreated diesel oil to obtain solution E; mixing solutions A and B in a reactor, heating and reacting, then adding mixture C, heating and reacting again, cooling, adding solution E, then adding dispersion D, heating and reacting again, cooling, separating the solid and liquid phases, and distilling to obtain the final product. The corrosion and scale inhibitor prepared in this application exhibits good temperature resistance.

Description

Technical Field

[0001] This application relates to the technical field of scale inhibitors, and more specifically, to a method for preparing a corrosion and scale inhibitor. Background Technology

[0002] As global crude oil extraction continues, reserves of high-quality light crude oil are gradually decreasing, and newly extracted crude oil often contains more heavy components. In particular, crude oil from some emerging oil-producing regions has higher density and viscosity, with relatively high asphaltenes and gums content. Simultaneously, in pursuit of higher yields of light oil products, operating conditions for processing plants are becoming increasingly stringent, and processing depths are increasing, leading to the heavier feedstock used in processes such as hydrocracking, catalytic diesel, and coking diesel. Impurities in the feedstock, such as metallic impurities, sulfur and nitrogen compounds, as well as large molecules (such as asphaltenes and gums), can easily cause scaling and other problems during processing, severely affecting the normal operation of the plant, reducing production efficiency, and increasing equipment maintenance costs and energy consumption.

[0003] To address this issue, scale inhibitors have been applied as an effective chemical method. Scale inhibitors do not alter existing processes, do not affect normal operation, and are convenient and flexible to add. However, in some petrochemical processes, such as hydrocracking and coking diesel, high temperatures are involved, but existing scale inhibitors have poor temperature resistance and cannot meet the actual operating conditions, resulting in frequent scaling and seriously affecting production efficiency and equipment lifespan.

[0004] Patent application CN114591760A discloses a scale inhibitor for use in oil refining processes, comprising component A, component B, component C, component D, and solvent. Component A is a nitrogen-oxygen radical-containing -N-heterocyclic compound; component B is di(2-ethylhexyl) phosphate; component C is ethylenediamine polyoxyethylene polyoxypropylene ether; component D is N,N′-di-sec-butyl-p-phenylenediamine; and the remainder is solvent. The mass ratio of component A:component B:component C:component D is 5:14:12:20, and the remainder is solvent.

[0005] The patent application document states that component B contains phosphorus, which may enter water bodies with wastewater after use, leading to eutrophication and posing a potential threat to the environment; component C has poor temperature resistance, and may break its molecular chains or change its structure due to its inability to withstand high temperatures during the oil refining process, thereby losing its scale inhibition properties such as dispersion and emulsification. Summary of the Invention

[0006] To address the problems of existing scale inhibitors, it is necessary to develop scale inhibitors that are phosphorus-free and temperature-resistant. Therefore, this application provides a method for preparing a corrosion and scale inhibitor.

[0007] This application provides a method for preparing a corrosion and scale inhibitor, which adopts the following technical solution:

[0008] A method for preparing a corrosion and scale inhibitor includes the following steps:

[0009] S1: Dissolve 25-35 parts by mass of modified polyaspartic acid in hydrotreated diesel oil, then add an antioxidant and mix well to obtain solution A;

[0010] S2: Disperse 15-25 parts by mass of hydrolyzed polymaleic anhydride in hydrotreated diesel oil and mix thoroughly to obtain dispersion B;

[0011] S3: Mix 6-10 parts by weight of imidazoline oleyl polyamine type corrosion inhibitor and 1-2 parts by weight of 2-amino-5-methyl-4-phenylthiazole evenly to obtain mixture C;

[0012] S4: Add 0.4~0.7 parts by mass of sodium dodecylbenzenesulfonate to hydrotreated diesel oil, mix well, then add nano titanium dioxide and nano zinc oxide in a mass ratio of 1~2:1, mix well, and obtain dispersion D;

[0013] S5: Dissolve 4-8 parts by mass of dispersant in hydrotreated diesel oil, mix thoroughly, and obtain solution E;

[0014] S6: Under an inert atmosphere, solution A and solution B are mixed in a reactor. After mixing evenly, the mixture is heated and reacted. Then, mixture C is added and mixed evenly. After heating and reacting, the mixture is cooled and solution E is added and mixed evenly. Then, dispersion D is added and mixed evenly. After heating and reacting, the mixture is cooled, solid and liquid are separated, and distilled to obtain the corrosion and scale inhibitor.

[0015] The total amount of nano-titanium dioxide and nano-zinc oxide is 4 to 7 parts by mass.

[0016] Preferably, in step S6, under an inert atmosphere, solution A and solution B are mixed in a reactor. After mixing evenly, the temperature is raised to 110~130℃ and reacted for 1.5~2.5h. Then, mixture C is added and mixed evenly. The temperature is raised to 150~170℃ and reacted for 4~6h. Then, the temperature is lowered to 90~110℃, solution E is added and mixed evenly. Then, dispersion D is added and mixed evenly. The temperature is raised to 130~150℃ and reacted for 3~5h. The temperature is lowered, solid-liquid separation is performed, and distillation is carried out to obtain the corrosion and scale inhibitor.

[0017] Preferably, the dispersant is polyisobutylene succinimide.

[0018] Preferably, the antioxidant is antioxidant 1010, and the amount of antioxidant 1010 is 0.5% to 1% of the mass of modified polyaspartic acid.

[0019] Beneficial effects: First, after mixing solutions A and B, the molecular chains of modified polyaspartic acid and hydrolyzed polymaleic anhydride intertwine and become entangled, forming a denser protective film on the metal surface. This film more effectively prevents corrosive substances (such as sulfides and acidic substances) from contacting the metal. The corrosion inhibition mechanisms of the two complement each other. Modified polyaspartic acid primarily inhibits corrosion by chelating metal ions, while hydrolyzed polymaleic anhydride slows down corrosion by adsorbing onto the metal surface and altering its surface properties. This synergistic effect makes the corrosion inhibition more significant. Simultaneously, the chelating effect of modified polyaspartic acid effectively captures scale-forming metal ions (such as calcium and magnesium ions) in the water, while hydrolyzed polymaleic anhydride inhibits the growth of scale crystals, thus forming a highly efficient dual-defense mechanism for scale inhibition.

[0020] Secondly, the addition of imidazoline oleyl polyamine corrosion inhibitors and 2-amino-5-methyl-4-phenylthiazole allows them to form stable chemical bonds or intermolecular forces with the modified polyaspartic acid-hydrolyzed polymaleic anhydride protective film, strengthening the film structure and making it denser and more complete. This significantly enhances the barrier against corrosive substances (such as sulfides and acidic substances), providing more reliable corrosion protection for metal equipment in high-temperature, high-pressure, and chemically complex petroleum processing environments. Furthermore, the polar groups in their molecular structure can interact with the polar parts of organic scale, altering its surface properties and reducing its deposition tendency. Combined with the repulsive effect of the hydrophobic groups of modified polyaspartic acid on organic scale and the dispersing effect of hydrolyzed polymaleic anhydride on organic scale, a more comprehensive anti-organic scale deposition system is constructed. This maintains the cleanliness of equipment surfaces, ensuring normal equipment operation, and is particularly effective in preventing the decline in heat transfer efficiency caused by organic scale buildup in heat exchange equipment.

[0021] Finally, solution E is added first, followed by dispersion D. The dispersant in solution E creates favorable conditions for the uniform dispersion of nano-titanium dioxide and nano-zinc oxide in the system, enabling them to tightly bind with the previously formed protective film components and other corrosion and scale inhibitors. This effectively fills the micropores and defects in the protective film, making it denser and enhancing its barrier ability against corrosive substances (such as sulfides and acidic substances), significantly improving corrosion inhibition performance. Simultaneously, nano-titanium dioxide and nano-zinc oxide also possess certain photocatalytic activity and antibacterial properties. Under certain circumstances, they can decompose organic pollutants and microorganisms that may adhere to the metal surface, reducing the possibility of biofilm formation. This further improves the comprehensive protective efficacy of the corrosion and scale inhibition system, effectively ensuring the long-term stable operation of metal equipment under complex working conditions and reducing equipment failures and increased maintenance costs caused by corrosion, scaling, and microbial growth.

[0022] A preferred method for preparing modified polyaspartic acid includes the following steps:

[0023] Under an inert atmosphere, aspartic acid is dissolved in ethanolamine at 60-80℃ and mixed thoroughly to obtain an aspartic acid solution. The solution is then heated to 130-150℃ and reacted for 1.5-2.5 hours. Dioctyl terephthalate is then added and mixed thoroughly. The solution is heated to 150-170℃ and reacted for 3-5 hours. Modified silica is then added and mixed thoroughly. The solution is heated to 160-180℃ and reacted for 4-6 hours. The solution is then cooled to 80-100℃, a precipitant is added, and the solid and liquid phases are separated. The solution is washed and dried to obtain modified polyaspartic acid. The amount of dioctyl terephthalate used is 20%-30% of the mass of aspartic acid, and the amount of modified silica used is 5%-10% of the total mass of aspartic acid and dioctyl terephthalate.

[0024] Preferably, the mass fraction of aspartic acid in the aspartic acid solution is 30% to 40%.

[0025] Beneficial effects: First, due to the presence of dioctyl terephthalate and modified silica, the molecular structure of modified polyaspartic acid is more stable. The hydrophobic long chains of dioctyl terephthalate can be arranged in an orderly manner on the metal surface, forming a denser and more stable physical barrier layer. This greatly hinders the direct contact between corrosive substances such as sulfides and the surface of metal equipment, thus effectively protecting the metal equipment from sulfide corrosion even at high temperatures, allowing its corrosion inhibition performance to be fully utilized.

[0026] Secondly, modified polyaspartic acid exhibits excellent oleophobic properties. When faced with oily components such as gums and asphaltenes commonly found in diesel fuel, this oleophobic property demonstrates a strong repulsive force, effectively preventing the adsorption and deposition of coke precursors (such as gums and asphaltenes) on the equipment surface, thereby effectively reducing coke formation and maintaining the equipment's heat transfer efficiency and normal material flow.

[0027] Finally, a synergistic effect is formed between the chelating effect of modified polyaspartic acid and the adsorption function of modified silica. On the one hand, modified polyaspartic acid can chelate with scale-forming components (such as calcium carbonate and calcium sulfate) through its active groups, thus inhibiting scale formation at a chemical level. On the other hand, modified silica, with its abundant surface active sites, has a strong adsorption capacity for impurity ions in water, further reducing the possibility of scale formation. In addition, modified polyaspartic acid can also play a unique role in preventing various salt impurities that may be mixed in during processing. Through chelation with metal ions, it prevents these salts from crystallizing and depositing, thereby effectively avoiding the risk of blockage in key equipment such as pipes and heat exchangers, and ensuring the efficient and safe operation of the entire processing system.

[0028] Preferably, the method for preparing the modified silica includes the following steps:

[0029] (1) Add silica to an alkaline solution, mix evenly, heat to 60~80℃, mix for 2~4h, cool down, separate solid and liquid, wash, dry, and obtain hydroxylated silica;

[0030] (2) Add hydroxylated silica to toluene, mix well to obtain a suspension, then add oleic acid, mix well, then add dibutyltin dilaurate and mix well, heat to 80~100℃, react for 3~6h, cool down, separate solid and liquid, wash, dry to obtain pre-modified silica.

[0031] (3) Add the silane coupling agent to the ethanol aqueous solution, mix evenly, adjust the pH to 4~5, mix at room temperature for 1~1.5h to obtain the hydrolysate; then add the pre-modified silica, mix evenly, heat to 50~70℃, react for 2~5h, separate the solid and liquid, wash, dry to obtain the modified silica.

[0032] The amount of oleic acid used is 8% to 15% of the mass of silicon dioxide, and the amount of silane coupling agent used is 5% to 10% of the mass of silicon dioxide.

[0033] Preferably, the alkaline solution is a sodium hydroxide solution with a concentration of 0.5~1 mol / L, and the mass ratio of silicon dioxide to the alkaline solution is 1:(10~20).

[0034] Preferably, the mass fraction of silica in the suspension is 10% to 20%.

[0035] Preferably, the amount of dibutyltin dilaurate used is 0.5% to 2% of the mass of oleic acid.

[0036] Preferably, in the ethanol-water solution, the volume ratio of ethanol to water is (4~9):1.

[0037] Preferably, the mass ratio of the silica to the hydrolysate is 1:(10~15).

[0038] Beneficial Effects: Through the above modification steps, the structure of silica was optimized. The introduction of oleic acid and silane coupling agents coated the silica surface with an organic molecular layer. The long-chain hydrocarbon groups of oleic acid have good hydrophobicity and flexibility, enabling them to intertwine and interpenetrate with the molecular chains of polyaspartic acid, further enhancing the physical interaction between the two. The silane coupling agent acts as a "bridge" between silica and polyaspartic acid. The siloxane group at one end reacts with the hydroxyl groups on the silica surface, while the organic functional groups at the other end can chemically bond with polyaspartic acid, thus achieving a tight connection between the modified silica and polyaspartic acid at the molecular level. This allows the modified polyaspartic acid to be more firmly adsorbed onto the metal surface in practical applications, improving the durability of its corrosion inhibition and scale inhibition properties. In addition, the coating of the organic molecular layer not only improves its compatibility and binding force with polyaspartic acid but also provides silica with certain thermal and chemical stability. In high-temperature environments (such as the high-temperature reaction zone in diesel processing), the organic molecular layer can reduce the chemical reaction between silica and the surrounding medium, while its own thermal stability also helps to maintain the structural integrity of the entire modified polyaspartic acid.

[0039] Preferably, the modified polyaspartic acid further includes the following pretreatment steps before use:

[0040] S11: Disperse the modified polyaspartic acid in toluene and mix evenly to obtain a modified polyaspartic acid dispersion.

[0041] S12: At 70~80℃, aluminum isopropoxide is dissolved in anhydrous isopropanol and mixed evenly to obtain an aluminum isopropoxide solution. Then, deionized water and acetic acid are added to the aluminum isopropoxide solution to adjust the pH to 4~5. The reaction is carried out for 5~7 hours to obtain a transparent alumina sol.

[0042] S13: Slowly add the modified polyaspartic acid dispersion to the alumina sol in step S12, mix evenly, heat to 80~90℃, keep warm for 4~6h, then separate the solid and liquid, wash, and dry to obtain the product;

[0043] The mass ratio of the modified polyaspartic acid to aluminum isopropoxide is 1:(0.4~0.6).

[0044] Preferably, the mass ratio of the deionized water to aluminum isopropoxide is 1:4.

[0045] Preferably, the modified polyaspartic acid dispersion contains 10% to 15% by mass; and the aluminum isopropoxide solution contains 15% to 20% by mass.

[0046] Beneficial effects: On the one hand, the modified polyaspartic acid coated with alumina sol exhibits significantly improved mechanical strength and stability of the protective film. Alumina, with its stable chemical structure and physical properties, constructs a robust supporting framework. In harsh environments such as hydrocracking and catalytic diesel processing, characterized by high temperatures, high pressures, and highly corrosive media rich in hydrogen sulfide and acidic substances, this framework effectively resists the impact of external stresses and corrosive agents, strongly ensuring the integrity of the protective film and continuously and efficiently protecting metal equipment from corrosion.

[0047] On the other hand, the high specific surface area and excellent adsorption performance of alumina sol coating create favorable conditions for the adsorption and dispersion of scaling precursors. In operating conditions prone to scaling, such as coking diesel units, alumina can efficiently adsorb scaling precursors such as colloids, asphaltenes, and metal ions, preventing them from accumulating on the equipment surface and undergoing scaling reactions. Simultaneously, the anti-scaling properties of modified polyaspartic acid further synergistically inhibit the chemical reaction of adsorbed substances into scale, and throughout the entire operation of the unit, the coating structure significantly reduces the tendency of scale to adhere to the equipment surface. The rough surface and chemical inertness of alumina make it difficult for scale to adhere tightly, while modified polyaspartic acid reduces the affinity between scale and the surface at a chemical level. The two complement each other, effectively reducing scale deposition on the equipment.

[0048] Preferably, the preparation method of the corrosion and scale inhibitor further includes adding an additive accounting for 1.5% to 3.5% of the mass of the modified polyaspartic acid. The addition step of the additive is as follows: in step S3, after 2-amino-5-methyl-4-phenylthiazole, a portion of the additive is added, and the mixture is mixed evenly to obtain mixture C.

[0049] In step S6, after adding dispersion D, mixing evenly, heating to 130~150℃, and reacting for 3~5 hours, another part of the additive is added, reacting for 40~60 minutes, cooling, solid-liquid separation, and distillation are performed to obtain the corrosion and scale inhibitor; the additive includes polytetrafluoroethylene and polyether ether ketone.

[0050] Preferably, the additive undergoes the following pretreatment steps before use:

[0051] S21: Polytetrafluoroethylene and polyetheretherketone are subjected to plasma treatment with a power of 100~200W and a treatment time of 5~10min to obtain pretreated additives.

[0052] S22: Dissolve dopamine hydrochloride in tris(hydroxymethyl)aminomethane-hydrochloric acid buffer to prepare a dopamine solution with a concentration of 1~2 mg / ml;

[0053] S23: Add the pretreated additive to the dopamine solution, react at room temperature for 18-24 hours, separate the solid and liquid, wash until neutral, dry, and obtain the additive;

[0054] The ratio of the total mass of polytetrafluoroethylene and polyetheretherketone to the volume of dopamine solution is 1 g: (30~50) ml.

[0055] Preferably, the mass ratio of polytetrafluoroethylene to polyetheretherketone is (2~3):1.

[0056] Beneficial Effects: Pretreated additives can form a more stable and efficient protective layer in corrosion and scale inhibitor systems. Firstly, after plasma treatment, both additives exhibit increased surface activity. Upon reaction with dopamine hydrochloride, they can be better dispersed in the corrosion and scale inhibitor system and adsorbed and aggregated on the metal surface. This not only effectively prevents corrosive substances (such as sulfides and acids) from contacting the metal, reducing corrosion, but also helps reduce fluid erosion and wear on the metal surface, further protecting metal equipment. Furthermore, it provides the necessary mechanical strength support for the protective layer, ensuring its integrity under complex operating conditions (such as high temperature, high pressure, and fluid impact), preventing damage and thus continuously exerting its corrosion and scale inhibition effects.

[0057] Secondly, the addition of pretreated additives can reduce the surface energy of the metal surface, making it difficult for scale (such as calcium carbonate and calcium sulfate) and organic deposits (such as colloids and asphalt) to deposit and adhere to the metal surface. Even in the case of a small amount of scale formation, the smooth surface of polytetrafluoroethylene makes it difficult for the scale to adhere firmly and it is easy to fall off under the flushing of fluids, thereby keeping the surface of the metal equipment clean, improving the heat transfer efficiency and operational stability of the equipment, and reducing equipment failures and maintenance costs caused by scaling.

[0058] Finally, the additive exhibits a synergistic effect with other corrosion and scale inhibitors (such as modified polyaspartic acid, hydrolyzed polymaleic anhydride, and imidazoline oleyl polyamine corrosion inhibitors). Specifically, the chelating effect of modified polyaspartic acid can capture scale-forming metal ions in water, while the additive further inhibits the formation of scale from these captured ions. Simultaneously, the protective layer formed by the additive provides a more stable environment for the adsorption and action of modified polyaspartic acid and other components on the metal surface, allowing their corrosion and scale inhibition properties to be better utilized. This synergistic effect significantly improves the performance of the entire corrosion and scale inhibitor system, enabling it to adapt to more complex and harsh diesel processing environments and effectively protect metal equipment.

[0059] In summary, this application has the following beneficial effects:

[0060] 1. This application utilizes the chemical bonding and molecular chain entanglement between modified polyaspartic acid and hydrolyzed polymaleic anhydride to maintain the structural integrity of the entire system under high-temperature conditions. Furthermore, the corrosion inhibition mechanisms of the two components complement each other, suppressing corrosion reactions from different angles, such as chelating metal ions and adsorbing and altering the surface properties of the metal. Simultaneously, the addition of imidazoline oleyl polyamine corrosion inhibitor, 2-amino-5-methyl-4-phenylthiazole, and dispersion D further enhances the structural integrity and stability of the protective film. These components form stable chemical bonds or intermolecular forces with the existing protective film, significantly increasing the barrier against corrosive substances. This provides reliable and long-lasting corrosion protection for equipment operating under high temperature, high pressure, and complex and variable chemical substances, such as diesel processing equipment.

[0061] 2. The chelating effect of modified polyaspartic acid can precisely capture scale-forming metal ions (such as calcium and magnesium ions) in water, preventing them from combining with anions to form scale nuclei. Meanwhile, hydrolyzed polymaleic anhydride can effectively inhibit the growth of scale crystals, thus doubly blocking the formation pathways of scale (such as common scale types like calcium carbonate and calcium sulfate) from both the source and the process, constructing a highly efficient scale inhibition and defense mechanism. Simultaneously, the addition of imidazoline oleyl polyamine corrosion inhibitor, 2-amino-5-methyl-4-phenylthiazole, and dispersion D works synergistically with the above scale inhibition mechanism to inhibit the formation and deposition of organic scale from multiple angles.

[0062] 3. The addition of additives further enhances the anti-scaling performance. It can not only inhibit the adhesion and deposition of scale through its own chemical properties, but also work synergistically with other scale inhibitors to enhance the scale inhibition effect.

[0063] 4. The dispersant in solution E plays a crucial stabilizing and dispersing role in the entire system, ensuring that all components are uniformly dispersed in the hydrotreated diesel, preventing particle agglomeration and sedimentation, and enabling the corrosion and scale inhibitor to maintain stable physicochemical properties under different temperature, pressure and chemical environments, thus ensuring that the synergistic effect between the components can be continuously and effectively exerted. Detailed Implementation

[0064] The present application will be further described in detail below with reference to the embodiments.

[0065] The corrosion and scale inhibitor prepared in this application is mainly applicable to the early stages of processing such as hydrocracking, catalytic diesel, and coking diesel, including feedstock pretreatment and preliminary treatment of reaction products, to help reduce equipment corrosion and scaling.

[0066] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0067] Hydrolyzed polymaleic anhydride, 99%, purchased from Jingzhou Yinjie Chemical Co., Ltd.

[0068] Imidazoline oleyl polyamine corrosion inhibitor, purchased from Lanzhou Fine Chemical High-Tech Development Company;

[0069] 2-Amino-5-methyl-4-phenylthiazole was purchased from (Alfa) Henan Weitixi Chemical Technology Co., Ltd.

[0070] Polyaspartic acid was purchased from Shandong Delan Chemical Co., Ltd.

[0071] Silica has a particle size distribution of 10~15μm; nano zinc oxide and nano titanium oxide have a particle size distribution of 1~100nm; polytetrafluoroethylene and polyether ether ketone have a particle size distribution of 5~15μm. Before use, all the above particles are placed in a drying oven, dried at 80℃ to constant weight, and then lightly ground and dispersed.

[0072] Preparation Examples 1-3: Modified Silica

[0073] Preparation Example 1

[0074] (1) 100g of silica was slowly added to 1000g of sodium hydroxide solution with a concentration of 1mol / L while stirring at a speed of 500rpm. After the addition was completed, stirring was continued for 20min. Then the temperature was raised to 60℃ and the reaction was continued for 4h. After cooling to room temperature, centrifugation was performed, and the silica was washed with deionized water until neutral. It was then transferred to a vacuum drying oven and dried at 80℃ to constant weight to obtain hydroxylated silica.

[0075] (2) Hydroxylated silica was slowly added to 900g of toluene while stirring at 600rpm. After the addition was complete, stirring was continued for 30min. Then 8g of oleic acid was added and stirring was continued for 40min. Then 0.16g of dibutyltin dilaurate was added and stirring was continued for 15min. The heating device was turned on and the temperature was raised to 80℃. The reaction was carried out for 6h. The temperature was lowered to room temperature and centrifuged. The silica was washed three times with a mixed solvent of toluene and ethanol (volume ratio of toluene to ethanol was 2:1). The silica was then transferred to a vacuum drying oven and dried at 80℃ to constant weight to obtain pre-modified silica.

[0076] (3) Add 5g of γ-aminopropyltriethoxysilane to 495g of ethanol aqueous solution, stir and mix evenly, adjust the pH to between 4 and 5 with 10% acetic acid, stir at room temperature for 1h at 300rpm, then add pre-modified silica, adjust the speed to 500rpm, mix for 120min, raise the temperature to 50℃, react for 5h, cool to room temperature, centrifuge, wash twice with ethanol and deionized water respectively, transfer to vacuum drying oven, dry at 80℃ to constant weight to obtain modified silica.

[0077] In the ethanol-water solution, the volume ratio of ethanol to water is 4:1.

[0078] Preparation Example 2

[0079] (1) 100g of silica was slowly added to 2000g of sodium hydroxide solution with a concentration of 0.5mol / L while stirring at a speed of 500rpm. After the addition was completed, stirring was continued for 20min. Then the temperature was raised to 80℃ and the reaction was continued for 2h. After cooling to room temperature, centrifugation was performed, and the silica was washed with deionized water until neutral. It was then transferred to a vacuum drying oven and dried at 80℃ to constant weight to obtain hydroxylated silica.

[0080] (2) Hydroxylated silica was slowly added to 400g of toluene while stirring at 600rpm. After the addition was complete, stirring was continued for 60min. Then 15g of oleic acid was added and stirring was continued for 40min. Then 0.075g of dibutyltin dilaurate was added and stirring was continued for 15min. The heating device was turned on and the temperature was raised to 100℃. The reaction was carried out for 3h. The temperature was lowered to room temperature and centrifuged. The silica was washed 3 times with a mixed solvent of toluene and ethanol (volume ratio of toluene to ethanol was 2:1). The silica was then transferred to a vacuum drying oven and dried at 80℃ to constant weight to obtain pre-modified silica.

[0081] (3) Add 10g of γ-aminopropyltriethoxysilane to 490g of ethanol aqueous solution, stir and mix evenly, adjust the pH to between 4 and 5 with 10% acetic acid, stir at room temperature for 2.5h at 300rpm, then add pre-modified silica, adjust the speed to 500rpm, mix for 120min, raise the temperature to 70℃, react for 2h, cool to room temperature, centrifuge, wash twice with ethanol and deionized water respectively, transfer to vacuum drying oven, dry at 80℃ to constant weight to obtain modified silica.

[0082] In the ethanol-water solution, the volume ratio of ethanol to water is 9:1.

[0083] Preparation Example 3

[0084] (1) 100g of silica was slowly added to 1000g of sodium hydroxide solution with a concentration of 1mol / L while stirring at a speed of 500rpm. After the addition was completed, stirring was continued for 20min. Then the temperature was raised to 70℃ and the reaction was continued for 3h. After cooling to room temperature, centrifugation was performed, and the silica was washed with deionized water until neutral. It was then transferred to a vacuum drying oven and dried at 80℃ to constant weight to obtain hydroxylated silica.

[0085] (2) Hydroxylated silica was slowly added to 600g of toluene while stirring at 600rpm. After the addition was complete, stirring was continued for 40min. Then 12g of oleic acid was added and stirring was continued for 40min. Then 0.12g of dibutyltin dilaurate was added and stirring was continued for 15min. The heating device was turned on and the temperature was raised to 90℃. The reaction was carried out for 5h. The temperature was lowered to room temperature and centrifuged. The silica was washed three times with a mixed solvent of toluene and ethanol (volume ratio of toluene to ethanol was 2:1). The silica was then transferred to a vacuum drying oven and dried at 80℃ to constant weight to obtain pre-modified silica.

[0086] (3) Add 8g of γ-aminopropyltriethoxysilane to 492g of ethanol aqueous solution, stir and mix evenly, adjust the pH to between 4 and 5 with 10% acetic acid, stir at room temperature for 2h at 300rpm, then add pre-modified silica, adjust the speed to 500rpm, mix for 120min, raise the temperature to 60℃, react for 3h, cool to room temperature, centrifuge, wash twice with ethanol and deionized water alternately, transfer to a vacuum drying oven, dry at 80℃ to constant weight to obtain modified silica.

[0087] In the ethanol-water solution, the volume ratio of ethanol to water is 5:1.

[0088] Preparation Examples 4-6: Modified Polyaspartic Acid

[0089] Preparation Example 4

[0090] Under a nitrogen atmosphere, at 60°C, 400g of aspartic acid ground through an 80-mesh sieve was added to 933g of ethanolamine and stirred for 60min. The mixture was then heated to 130°C and reacted for 2.5h. 80g of dioctyl terephthalate was slowly added dropwise over 40min. After the addition was complete, the mixture was heated to 150°C and reacted for 5h. Then, 24g of modified silica was added and stirred for 30min. The mixture was then heated to 160°C and reacted for 6h. The mixture was cooled to 80°C and a 5% (w / w) calcium chloride solution was added dropwise until no precipitate formed. The mixture was then vacuum filtered, washed three times with anhydrous ethanol, and transferred to a vacuum drying oven. It was dried at 80°C for 6h to obtain modified polyaspartic acid.

[0091] The modified silica was derived from Preparation Example 1.

[0092] Preparation Example 5

[0093] Under a nitrogen atmosphere, at 80°C, 400g of aspartic acid ground through an 80-mesh sieve was added to 600g of ethanolamine and stirred for 60min. The mixture was then heated to 150°C and reacted for 1.5h. 120g of dioctyl terephthalate was slowly added dropwise over 60min. After the addition was complete, the mixture was heated to 170°C and reacted for 3h. Then, 52g of modified silica was added and stirred for 60min. The mixture was then heated to 180°C and reacted for 4h. The mixture was cooled to 100°C and a 5% (w / w) calcium chloride solution was added dropwise until no precipitate formed. The mixture was then vacuum filtered, washed three times with anhydrous ethanol, and transferred to a vacuum drying oven. It was dried at 80°C for 6h to obtain modified polyaspartic acid.

[0094] The modified silica was prepared in Example 2.

[0095] Preparation Example 6

[0096] Under a nitrogen atmosphere, at 70°C, 400g of aspartic acid ground through an 80-mesh sieve was added to 800g of ethanolamine and stirred for 60min. The mixture was then heated to 140°C and reacted for 2h. 100g of dioctyl terephthalate was slowly added dropwise over 50min. After the addition was complete, the mixture was heated to 160°C and reacted for 4h. Then, 40g of modified silica was added and stirred for 60min. The mixture was then heated to 170°C and reacted for 5h. The mixture was cooled to 90°C and a 5% (w / w) calcium chloride solution was added dropwise until no precipitate formed. The mixture was then vacuum filtered, washed three times with anhydrous ethanol, and transferred to a vacuum drying oven. It was dried at 80°C for 6h to obtain modified polyaspartic acid.

[0097] The modified silica was prepared in Example 3.

[0098] Preparation Example 7

[0099] S11: Add 400g of modified polyaspartic acid to 3600g of toluene, stir and mix for 30min at 300rpm to obtain a dispersion with a mass fraction of 10%;

[0100] S12: Add 907g of isopropanol to a three-necked flask and place it in a constant temperature water bath at 70℃. Turn on the stirrer and turn the speed at 300rpm. Then slowly add 160g of aluminum isopropoxide and stir until the aluminum isopropoxide is fully dissolved to obtain a solution with a mass fraction of 15%. Then, use a constant pressure dropping funnel to add 40g of deionized water (conductivity not higher than 1μS / cm) drop by drop to the above solution, with the dropping rate controlled at 10~20 drops per minute. At the same time, add acetic acid to adjust the pH to between 4 and 5. React for 7 hours to obtain a transparent alumina sol.

[0101] S13: Slowly add the dispersion dropwise to the alumina sol in step S12, while adjusting the stirring speed to 500 rpm. After the addition is complete, raise the temperature to 80℃ and continue stirring for 6 hours. After the reaction is complete, transfer the reaction system to a rotary evaporator. Remove isopropanol and toluene solvent by vacuum distillation at a vacuum degree of 0.09 MPa and a temperature of 80℃ to obtain a solid product. Wash the solid product three times with an equal volume of n-hexane, transfer it to a vacuum drying oven, and dry it at 70℃ for 12 hours to obtain the final product.

[0102] The modified polyaspartic acid was derived from Preparation Example 6.

[0103] Preparation Example 8

[0104] S11: Add 400g of modified polyaspartic acid to 2267g of toluene, stir and mix for 30min at 300rpm to obtain a dispersion with a mass fraction of 15%;

[0105] S12: Add 960g of isopropanol to a three-necked flask and place it in a constant temperature water bath at 80℃. Turn on the stirrer and turn the speed at 300rpm. Then slowly add 240g of aluminum isopropoxide and stir until the aluminum isopropoxide is fully dissolved to obtain a solution with a mass fraction of 20%. Then, use a constant pressure dropping funnel to add 60g of deionized water (conductivity not higher than 1μS / cm) drop by drop to the above solution, with the dropping rate controlled at 10~20 drops per minute. At the same time, add acetic acid to adjust the pH to between 4 and 5. React for 5 hours to obtain a transparent alumina sol.

[0106] S13: Slowly add the dispersion dropwise to the alumina sol in step S12, while adjusting the stirring speed to 500 rpm. After the addition is complete, raise the temperature to 90℃ and continue stirring for 4 hours. After the reaction is complete, transfer the reaction system to a rotary evaporator. Remove isopropanol and toluene solvent by vacuum distillation at a vacuum degree of 0.09 MPa and a temperature of 80℃ to obtain a solid product. Wash the solid product three times with an equal volume of n-hexane, transfer it to a vacuum drying oven, and dry it at 70℃ for 16 hours to obtain the final product.

[0107] The modified polyaspartic acid was derived from Preparation Example 6.

[0108] Example 1

[0109] This embodiment provides a method for preparing a corrosion and scale inhibitor, comprising the following steps:

[0110] S1: At 50℃, 250g of modified polyaspartic acid is slowly added to 750g of hydrotreated diesel oil and stirred continuously at 300rpm for 30min until homogeneous. Then, 1.25g of antioxidant 1010 is added and the mixture is stirred for another 20min to obtain a solution A with a modified polyaspartic acid mass fraction of 25%.

[0111] S2: Add 150g of hydrolyzed polymaleic anhydride to 850g of hydrotreated diesel oil and stir continuously at 300rpm for 40min until homogeneous to obtain a dispersion B with a mass fraction of 15% hydrolyzed polymaleic anhydride.

[0112] S3: Place 60g of imidazoline oleyl polyamine corrosion inhibitor and 10g of 2-amino-5-methyl-4-phenylthiazole in a stirring device with a speed of 300rpm and stir for 30min until homogeneous to obtain mixture C;

[0113] S4: First, add 4g of sodium dodecylbenzenesulfonate to 456g of hydrotreated diesel oil and stir at 300rpm for 25min. Then, add 20g of nano titanium dioxide and 20g of nano zinc oxide respectively and continue stirring and mixing for 40min until uniform, to obtain a dispersion D with a total mass fraction of 8% for nano titanium dioxide and nano zinc oxide.

[0114] S5: Add 40g of polyisobutylene succinimide to 960g of hydrotreated diesel oil, and stir continuously at 300rpm for 50min at 40℃ to obtain a solution E with a polyisobutylene succinimide mass fraction of 4%.

[0115] S6: Under a nitrogen atmosphere, solutions A and B are added to a reaction vessel and stirred at 200 rpm for 15 min. The mixture is then heated to 110°C and reacted for 2.5 h. Mixture C is added and stirred at 300 rpm for 20 min until homogeneous. The mixture is then heated to 150°C and reacted for 6 h. The mixture is then cooled to 90°C and solution E is added and stirred at 400 rpm for 60 min. Dispersion D is then added and stirred for another 120 min. The mixture is then heated to 130°C and reacted for 5 h. The mixture is then cooled, and the product is filtered through a 100-mesh filter to remove residual large particles. The filtrate is then transferred to a vacuum distillation apparatus and evaporated at 80°C and 0.07~0.09 MPa for 3 h to obtain a slow-release scale inhibitor.

[0116] The modified polyaspartic acid was derived from Preparation Example 4.

[0117] Example 2

[0118] This embodiment provides a method for preparing a corrosion and scale inhibitor, comprising the following steps:

[0119] S1: At 70℃, 350g of modified polyaspartic acid is slowly added to 650g of hydrotreated diesel oil and stirred continuously at 300rpm for 30min until homogeneous. Then, 3.5g of antioxidant 1010 is added and the mixture is stirred for another 20min to obtain a solution A with a modified polyaspartic acid mass fraction of 35%.

[0120] S2: Add 250g of hydrolyzed polymaleic anhydride to 750g of hydrotreated diesel oil and stir continuously at 300rpm for 40min until homogeneous to obtain a dispersion B with a mass fraction of 25% of hydrolyzed polymaleic anhydride.

[0121] S3: Place 100g of imidazoline oleyl polyamine corrosion inhibitor and 20g of 2-amino-5-methyl-4-phenylthiazole in a stirring device with a speed of 300 rpm and stir for 30 minutes until homogeneous to obtain mixture C;

[0122] S4: First, add 7g of sodium dodecylbenzenesulfonate to 506g of hydrotreated diesel oil and stir at 300rpm for 25min. Then, add 42g of nano titanium dioxide and 28g of nano zinc oxide respectively and continue stirring and mixing for 40min until uniform, to obtain a dispersion D with a total mass fraction of 12% of nano titanium dioxide and nano zinc oxide.

[0123] S5: Add 80g of polyisobutylene succinimide to 920g of hydrotreated diesel oil, and stir continuously at 300rpm for 50min at 60℃ to obtain a solution E with a polyisobutylene succinimide mass fraction of 8%.

[0124] S6: Under a nitrogen atmosphere, solutions A and B are added to a reaction vessel and stirred at 200 rpm for 15 min. The mixture is then heated to 130°C and reacted for 1.5 h. Mixture C is added and stirred at 300 rpm for 20 min until homogeneous. The mixture is then heated to 170°C and reacted for 4 h. The mixture is then cooled to 110°C and solution E is added. The mixture is stirred at 400 rpm for 60 min. Dispersion D is then added and stirred for another 120 min. The mixture is then heated to 150°C and reacted for 4 h. The mixture is then cooled, and the product is filtered through a 100-mesh filter to remove residual large particles. The filtrate is then transferred to a vacuum distillation apparatus and evaporated at 80°C and 0.07~0.09 MPa for 2 h to obtain a slow-release scale inhibitor.

[0125] The modified polyaspartic acid was derived from Preparation Example 5.

[0126] Example 3

[0127] This embodiment provides a method for preparing a corrosion and scale inhibitor, comprising the following steps:

[0128] S1: At 60℃, 300g of modified polyaspartic acid is slowly added to 700g of hydrotreated diesel oil and stirred continuously at 300rpm for 30min until homogeneous. Then, 3g of antioxidant 1010 is added and the mixture is stirred for another 20min to obtain a solution A with a modified polyaspartic acid mass fraction of 30%.

[0129] S2: Add 200g of hydrolyzed polymaleic anhydride to 800g of hydrotreated diesel oil and stir continuously at 300rpm for 40min until homogeneous to obtain a dispersion B with a mass fraction of 20% of hydrolyzed polymaleic anhydride.

[0130] S3: Place 80g of imidazoline oleyl polyamine corrosion inhibitor and 15g of 2-amino-5-methyl-4-phenylthiazole in a stirring device with a speed of 300 rpm and stir for 30 minutes until homogeneous to obtain mixture C;

[0131] S4: First, add 6g of sodium dodecylbenzenesulfonate to 534g of hydrotreated diesel oil and stir at 300rpm for 25min. Then, add 40g of nano titanium dioxide and 20g of nano zinc oxide respectively and continue stirring and mixing for 40min until uniform, to obtain a dispersion D with a total mass fraction of 10% of nano titanium dioxide and nano zinc oxide.

[0132] S5: Add 60g of polyisobutylene succinimide to 940g of hydrotreated diesel oil, and stir continuously at 300rpm for 50min at 50℃ to obtain a solution E with a polyisobutylene succinimide mass fraction of 6%.

[0133] S6: Under a nitrogen atmosphere, solutions A and B are added to a reaction vessel and stirred at 200 rpm for 15 min. The mixture is then heated to 120°C and reacted for 2 h. Mixture C is added and stirred at 300 rpm for 20 min until homogeneous. The mixture is then heated to 160°C and reacted for 5 h. The mixture is then cooled to 100°C and solution E is added. The mixture is stirred at 400 rpm for 60 min. Dispersion D is then added and stirred for another 120 min. The mixture is then heated to 140°C and reacted for 3 h. The mixture is then cooled, and the product is filtered through a 100-mesh filter to remove residual large particles. The filtrate is then transferred to a vacuum distillation apparatus and evaporated at 80°C and 0.07~0.09 MPa for 2.5 h to obtain a slow-release scale inhibitor.

[0134] The modified polyaspartic acid was derived from Preparation Example 6.

[0135] Example 4

[0136] The difference between this embodiment and Embodiment 3 is that:

[0137] The modified polyaspartic acid was prepared from Example 7.

[0138] Everything else is the same as in Example 3.

[0139] Example 5

[0140] The difference between this embodiment and Embodiment 3 is that:

[0141] The modified polyaspartic acid was prepared from Example 8.

[0142] Everything else is the same as in Example 3.

[0143] Example 6

[0144] The difference between this embodiment and Embodiment 5 is that:

[0145] S3: Place 80g of imidazoline oleyl polyamine corrosion inhibitor, 15g of 2-amino-5-methyl-4-phenylthiazole and 2.25g of additive in a stirring device with a speed of 300rpm and stir for 30min until homogeneous to obtain mixture C;

[0146] S6: Under a nitrogen atmosphere, solutions A and B are added to a reaction vessel and stirred at 200 rpm for 15 min. The mixture is then heated to 120°C and reacted for 2 h. Mixture C is added and stirred at 300 rpm for 20 min until homogeneous. The mixture is then heated to 160°C and reacted for 5 h. The mixture is then cooled to 100°C and solution E is added. The mixture is stirred at 400 rpm for 60 min. Dispersion D is then added and stirred for another 120 min. The mixture is then heated to 140°C and reacted for 3 h. 2.25 g of additive is added and stirred for 40 min. The mixture is then cooled and the product is filtered through a 100-mesh filter to remove residual large particles. The filtrate is then transferred to a vacuum distillation apparatus and evaporated at 80°C and 0.07~0.09 MPa for 2.5 h to obtain a slow-release scale inhibitor.

[0147] The additives undergo the following pretreatment steps before use:

[0148] S21: Plasma treatment was performed on 3g of polytetrafluoroethylene and 1.5g of polyetheretherketone at a power of 100W for 10min to obtain a pretreatment additive.

[0149] S22: Dissolve 270 mg of dopamine hydrochloride in 135 ml of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer (pH 8.5) to prepare a dopamine solution with a concentration of 2 mg / ml;

[0150] S23: Add the pretreated additive to the dopamine solution and react at room temperature for 18 hours. Separate the solid and liquid components, wash with deionized water until neutral, and transfer to a vacuum drying oven to dry at 60°C to constant weight to obtain the additive.

[0151] The rest is the same as in Example 5.

[0152] Example 7

[0153] The difference between this embodiment and Embodiment 6 is that:

[0154] In step S3, the amount of additive used is 5.25g; in step S6, the amount of additive used is 5.25g.

[0155] The additives undergo the following pretreatment steps before use:

[0156] S21: Plasma treatment was performed on 7.9g of polytetrafluoroethylene and 2.6g of polyetheretherketone at a power of 200W for 5min to obtain a pretreatment additive.

[0157] S22: Dissolve 525 mg of dopamine hydrochloride in 525 ml of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer (pH 8.5) to prepare a dopamine solution with a concentration of 1 mg / ml;

[0158] S23: Add the pretreated additive to the dopamine solution and react at room temperature for 24 hours. Separate the solid and liquid, wash with deionized water until neutral, and transfer to a vacuum drying oven to dry at 60°C to constant weight to obtain the additive.

[0159] The rest is the same as in Example 6.

[0160] Comparative Example 1

[0161] The difference between this comparative example and Example 1 is that the polyaspartic acid was unmodified and sourced from the market.

[0162] Everything else is the same as in Example 1.

[0163] Performance testing

[0164] The test feedstock used in this performance test was hydrocracking feedstock oil.

[0165] 1. Corrosion rate determination

[0166] (1) Hanging method

[0167] The corrosion and scale inhibitors prepared in Examples 1-7 and Comparative Example 1 were tested according to GB / T18175-2014 standard. Nine reactors were taken and labeled as test pieces 1-9. 1.5L of hydrocracking feedstock oil was added to each reactor. The slow-release scale inhibitors from Examples 1-7 and Comparative Example 1 were added to the first eight reactors in sequence, with a concentration of 100ppm for each. The last reactor served as a blank control group. Three carbon steel sheets and three stainless steel sheets were placed in each reactor. The temperature was raised to 200℃ and held for 72h. After the test, the reactors were cooled, washed, dried, and weighed. The average value of each group was calculated, and the corrosion rate of test pieces 1-8 was calculated in conjunction with the blank control group. The test results are shown in Table 1. The carbon steel sheets and stainless steel sheets were cleaned, dried, and weighed beforehand, and the initial mass was recorded to an accuracy of 0.1mg.

[0168] (2) Dynamic corrosion performance determination

[0169] The corrosion and scale inhibitors prepared in Examples 1-7 and Comparative Example 1 were tested according to the HG-T2160-2008 standard. Nine reactors were used, labeled as samples 1-9, and 1.5 L of hydrocracking feedstock oil was added to each. The slow-release scale inhibitors from Examples 1-7 and Comparative Example 1 were added to the first eight reactors, with a concentration of 100 ppm for each. The last reactor served as a blank control group. Three carbon steel test tube samples were placed in each reactor. The temperature was raised to 200℃ and maintained for 7 days. After the test, the samples were cooled, washed, dried, and weighed. The average value of each group was calculated, and the corrosion rate of samples 1-8 was calculated in conjunction with the blank control group. The test results are shown in Table 2. The carbon steel test tube samples were cleaned, dried, and weighed beforehand, and the initial mass was recorded to an accuracy of 0.1 mg.

[0170] 2. Scale inhibition rate determination

[0171] The corrosion and scale inhibitors prepared in Examples 1-7 and Comparative Example 1 were tested according to HG / T2024-2009. Nine measuring tubes were selected. The first eight tubes were fed with hydrocracking feedstock oil mixed with the corrosion and scale inhibitor at a flow rate of 120 g / h. The last tube served as a blank control group, with hydrocracking feedstock oil fed into the tube at a flow rate of 120 g / h. All measuring tubes were heated using a heater and maintained at 200°C for 24 hours. After cooling to room temperature, the feedstock oil was drained, washed, dried, and weighed to measure the amount of scale buildup. The scale inhibition rate was obtained based on the different amounts of scale buildup in the blank control group and the experimental group using the corrosion and scale inhibitors in Examples 1-7 and Comparative Example 1. The test results are shown in Table 3. The test tubes were cleaned, dried, and weighed beforehand, and the initial mass was recorded to an accuracy of 0.1 mg.

[0172] Table 1. Corrosion rate performance test results of specimens 1-8

[0173]

[0174] Table 2. Results of dynamic corrosion rate test for samples 1-8

[0175]

[0176] Table 3. Test results of scale inhibition rate of corrosion and scale inhibitors prepared in Examples 1-7 and Comparative Example 1

[0177]

[0178] Analysis of the test results in Tables 1-3 shows that:

[0179] As can be seen from Example 1 and Comparative Example 1, the modification treatment of polyaspartic acid brought about a significant performance improvement in the field of hydrocracking feedstock oil. This is because polyaspartic acid, dioctyl benzoate and silica form a stable composite system through synergistic effect, which not only enhances the dispersibility of polyaspartic acid in feedstock oil, but also improves its slow-release scale inhibition performance.

[0180] As can be seen from Examples 1-3, by optimizing and adjusting the distribution ratio of each group, the corrosion and scale inhibitors all exhibit good corrosion and scale inhibition performance.

[0181] As can be seen from Examples 3-5, by pretreating the modified polyaspartic acid, a layer of alumina sol will be coated on the surface of the modified polyaspartic acid. This composite structure can be better adsorbed on the metal surface. At the same time, alumina can also act as a physical barrier to prevent the corrosive medium from contacting the metal, thereby improving the corrosion inhibition performance.

[0182] The pretreated modified polyaspartic acid exhibits improved dispersion properties, which helps it to distribute evenly in the feedstock oil and better interact with scale-forming ions, preventing them from crystallizing and forming scale. Simultaneously, the combination of alumina sol and modified polyaspartic acid produces a synergistic effect; the alumina sol adsorbs some scale-forming ions, while the modified polyaspartic acid prevents these ions from further agglomerating and growing, thereby improving the scale inhibition rate.

[0183] As can be seen from Examples 5-7, by introducing additives, they can work synergistically with components such as modified polyaspartic acid to form a denser protective film, while enhancing the adsorption and scale-forming ion dispersion capabilities of the corrosion and scale inhibitor system, thus preventing the aggregation and crystallization of scale-forming ions to a greater extent.

Claims

1. A method for preparing a corrosion and scale inhibitor, characterized in that, Includes the following steps: S1: Dissolve 25-35 parts by mass of modified polyaspartic acid in hydrotreated diesel oil, then add an antioxidant and mix well to obtain solution A; S2: Disperse 15-25 parts by mass of hydrolyzed polymaleic anhydride in hydrotreated diesel oil, mix thoroughly to obtain dispersion B; S3: Mix 6-10 parts by weight of imidazoline oleyl polyamine corrosion inhibitor and 1-2 parts by weight of 2-amino-5-methyl-4-phenylthiazole evenly to obtain mixture C; S4: Add 0.4~0.7 parts by weight of sodium dodecylbenzenesulfonate to hydrogenated diesel oil, mix evenly, then add nano titanium dioxide and nano zinc oxide in a mass ratio of 1~2:1, mix evenly, and obtain dispersion D; S5: Dissolve 4-8 parts by mass of dispersant in hydrotreated diesel oil, mix thoroughly to obtain solution E; S6: Under an inert atmosphere, solution A and solution B are mixed in a reactor. After mixing evenly, the mixture is heated and reacted. Then, mixture C is added and mixed evenly. After heating and reacting, the temperature is lowered and solution E is added and mixed evenly. Then, dispersion D is added and mixed evenly. After heating and reacting, the temperature is lowered, solid-liquid separation is performed, and distillation is carried out to obtain the corrosion and scale inhibitor. The total amount of nano-titanium dioxide and nano-zinc oxide is 4-7 parts by mass; The method for preparing the modified polyaspartic acid includes the following steps: Under an inert atmosphere, aspartic acid was dissolved in ethanolamine at 60-80℃ and mixed thoroughly to obtain an aspartic acid solution. The solution was then heated to 130-150℃ and reacted for 1.5-2.5 hours. Dioctyl terephthalate was then added and mixed thoroughly. The solution was then heated to 150-170℃ and reacted for 3-5 hours. Modified silica was then added and mixed thoroughly. The solution was then heated to 160-180℃ and reacted for 4-6 hours. The solution was then cooled to 80-100℃, a precipitant was added, and the solid and liquid phases were separated. The solution was washed and dried to obtain modified polyaspartic acid. The modified silica is obtained by introducing oleic acid and a silane coupling agent to coat the surface of silica with an organic molecular layer.

2. The method for preparing the corrosion and scale inhibitor according to claim 1, characterized in that, In step S6, under an inert atmosphere, solutions A and B are mixed in a reactor. After uniform mixing, the temperature is raised to 110-130°C and reacted for 1.5-2.5 hours. Then, mixture C is added and mixed uniformly. The temperature is raised to 150-170°C and reacted for 4-6 hours. After cooling to 90-110°C, solution E is added and mixed uniformly. Then, dispersion D is added and mixed uniformly. The temperature is raised to 130-150°C and reacted for 3-5 hours. After cooling, solid-liquid separation and distillation are performed to obtain the corrosion and scale inhibitor.

3. The method for preparing the corrosion and scale inhibitor according to claim 1, characterized in that, The dispersant is polyisobutylene succinimide.

4. The method for preparing the corrosion and scale inhibitor according to claim 1, characterized in that, The antioxidant is antioxidant 1010, and the amount of antioxidant 1010 is 0.5% to 1% of the mass of modified polyaspartic acid.

5. The method for preparing the corrosion and scale inhibitor according to claim 1, characterized in that, The amount of dioctyl terephthalate used is 20% to 30% of the mass of aspartic acid; the amount of modified silica used is 5% to 10% of the total mass of aspartic acid and dioctyl terephthalate.

6. The method for preparing the corrosion and scale inhibitor according to claim 5, characterized in that, The method for preparing the modified silica includes the following steps: (1) Add silica to an alkaline solution, mix evenly, heat to 60~80℃, mix for 2~4h, cool down, separate solid and liquid, wash, dry, and obtain hydroxylated silica; (2) Add hydroxylated silica to toluene, mix well to obtain a suspension, then add oleic acid, mix well, then add dibutyltin dilaurate and mix well, heat to 80~100℃, react for 3~6h, cool down, separate solid and liquid, wash, dry to obtain pre-modified silica. (3) Add the silane coupling agent to the ethanol aqueous solution, mix evenly, adjust the pH to 4~5, mix at room temperature for 1~1.5h to obtain the hydrolysate; then add the pre-modified silica, mix evenly, heat to 50~70℃, react for 2~5h, separate the solid and liquid, wash, dry to obtain the modified silica. The amount of oleic acid used is 8% to 15% of the mass of silicon dioxide, and the amount of silane coupling agent used is 5% to 10% of the mass of silicon dioxide.

7. The method for preparing the corrosion and scale inhibitor according to claim 5, characterized in that, Before use, the modified polyaspartic acid also includes the following pretreatment steps: S11: Disperse the modified polyaspartic acid in toluene and mix evenly to obtain a modified polyaspartic acid dispersion. S12: At 70~80℃, aluminum isopropoxide is dissolved in anhydrous isopropanol and mixed evenly to obtain an aluminum isopropoxide solution. Then, deionized water and acetic acid are added to the aluminum isopropoxide solution to adjust the pH to 4~5. The reaction is carried out for 5~7 hours to obtain a transparent alumina sol. S13: Slowly add the modified polyaspartic acid dispersion to the alumina sol in step S12, mix evenly, heat to 80~90℃, keep warm for 4~6h, then separate the solid and liquid, wash, and dry to obtain the product; The mass ratio of the modified polyaspartic acid to aluminum isopropoxide is 1:(0.4~0.6).

8. The method for preparing the corrosion and scale inhibitor according to claim 1, characterized in that, The preparation method of the corrosion and scale inhibitor further includes adding an additive accounting for 1.5% to 3.5% of the mass of modified polyaspartic acid. The addition steps are as follows: in step S3, after 2-amino-5-methyl-4-phenylthiazole, a portion of the additive is added and mixed evenly to obtain mixture C; in step S6, after adding dispersion D and mixing evenly, the mixture is heated to 130 to 150°C and reacted for 3 to 5 hours, another portion of the additive is added and reacted for 40 to 60 minutes. The mixture is then cooled, the solid and liquid are separated, and distilled to obtain the corrosion and scale inhibitor. The additive includes polytetrafluoroethylene and polyether ether ketone.

9. The method for preparing the corrosion and scale inhibitor according to claim 8, characterized in that, Before use, the additive undergoes the following pretreatment steps: S21: Polytetrafluoroethylene and polyetheretherketone are subjected to plasma treatment with a power of 100~200W and a treatment time of 5~10min to obtain a pretreated additive. S22: Dissolve dopamine hydrochloride in tris(hydroxymethyl)aminomethane-hydrochloric acid buffer to prepare a dopamine solution with a concentration of 1~2 mg / ml; S23: Add the pretreatment additive to the dopamine solution, react at room temperature for 18-24 hours, separate the solid and liquid, wash until neutral, dry, and obtain the additive; the ratio of the total mass of the polytetrafluoroethylene and polyether ether ketone to the volume of the dopamine solution is 1g:(30-50)ml.

10. The method for preparing the corrosion and scale inhibitor according to claim 8, characterized in that, The mass ratio of polytetrafluoroethylene to polyetheretherketone is (2~3):1.

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