Efficient water-soluble corrosion inhibitor for oil refining device and preparation method of efficient water-soluble corrosion inhibitor

Abstract

The invention relates to the field of petroleum refining industry, and particularly discloses a high-efficiency water-soluble corrosion inhibitor for an oil refining device and a preparation method of the high-efficiency water-soluble corrosion inhibitor for the oil refining device, and the corrosion inhibitor is prepared from the following raw materials in parts by weight: 20-40 parts of an organic amine compound; 15 to 30 parts of organic acid; 5 to 15 parts of a surfactant; 30 to 50 parts of a solvent; 1-5 parts of a metal deactivator; 0.5-3 parts of a dispersing aid; according to the invention, the specifically prepared intermediate A is introduced to carry out molecular modification on the traditional amine salt, so that the film-forming property and adhesion firmness of the corrosion inhibitor are qualitatively improved; the intermediate A serves as a functional polymer and can be subjected to graft copolymerization with amine salt, and a layer of compact, stable and hydrophobic protective film is formed on the metal surface. The film can more effectively prevent a corrosive medium from being in contact with a metal matrix, so that the corrosion inhibition efficiency is improved from about 70% of common amine salt to 90% or above, and efficient protection is achieved.

Description

Technical Field

[0001] This invention belongs to the field of petroleum refining industry, specifically a highly efficient water-soluble corrosion inhibitor for oil refining equipment and its preparation method. Background Technology

[0002] In the petroleum refining industry, the top of the atmospheric and vacuum distillation unit and its condensation cooling system are critical links in process corrosion prevention. This area is mostly made of carbon steel, and the corrosive media primarily originate from hydrogen chloride, hydrogen sulfide, carbon dioxide produced during crude oil processing, as well as moisture formed from steam condensation. These elements combine to create a harsh environment characterized by high temperature, high humidity, and a high concentration of corrosive ions. To protect the equipment, a process measure of continuously injecting water-soluble corrosion inhibitors is typically employed. These inhibitors are mostly based on amine salts such as imidazoline and amides, formed by the reaction of organic amines and organic acids. They form a monomolecular protective film through directional adsorption on the metal surface, preventing contact between the corrosive media and the substrate, thereby inhibiting corrosion.

[0003] However, traditional amine salt-based corrosion inhibitors widely used in existing technologies exhibit a significant drawback in actual operation: the protective film they form is often not dense or robust enough, and is prone to desorption under high-speed fluid scouring or temperature fluctuations, leading to film damage and poor self-repair capability. This directly manifests as limited and unstable corrosion inhibition efficiency, especially in environments with high chloride ion concentrations, where the risk of pitting corrosion remains prominent. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a highly efficient water-soluble corrosion inhibitor for oil refining units, thereby solving the problem that traditional amine salt corrosion inhibitors in the prior art suffer from limited and unstable corrosion inhibition efficiency due to the non-dense and weak protective film.

[0005] A highly efficient water-soluble corrosion inhibitor for use in oil refining units is prepared from raw materials comprising the following components in parts by weight:

[0006] 20-40 parts organic amine compound; 15-30 parts organic acid; 5-15 parts surfactant; 30-50 parts solvent; 1-5 parts metal passivator; 0.5-3 parts dispersant.

[0007] Preferably, the organic amine compound is at least one selected from morpholine, cyclohexylamine, diethanolamine, and triethanolamine;

[0008] The organic acid is at least one of lauric acid, oleic acid, citric acid, and aminotrimethylenephosphonic acid;

[0009] The solvent is at least one of deionized water, ethanol, and isopropanol.

[0010] Preferably, the surfactant is a fatty alcohol polyoxyethylene ether, an alkylphenol polyoxyethylene ether, sodium dodecylbenzene sulfonate, or sodium dodecyl sulfate;

[0011] The metal passivating agent is benzotriazole, methylbenzotriazole, or a thiadiazole derivative;

[0012] The dispersing agent is polyvinylpyrrolidone, sodium polyacrylate, or hydroxymethyl cellulose.

[0013] A method for preparing the above-mentioned highly efficient water-soluble corrosion inhibitor includes the following steps:

[0014] S1. In the presence of a catalyst, the modified monomer is reacted at 50-100℃ to prepare intermediate A;

[0015] S2. React organic amine compounds with organic acids at 60-80℃ for 1-2 hours to generate amine salts;

[0016] S3. The amine salt generated in step S2 is modified using intermediate A obtained in step S1 to obtain the modified amine salt;

[0017] S4. Add the surfactant, metal passivator and dispersant to the solvent and stir to dissolve at 40-60℃ to obtain mixture B;

[0018] S5. Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 50-70℃ for 1-3 hours, and cool to room temperature to obtain the highly efficient water-soluble corrosion inhibitor.

[0019] Preferably, step S1 specifically includes the following sub-steps:

[0020] S11. Add the catalyst to the reaction vessel and preheat it to 50-70℃;

[0021] S12. Slowly add the modified monomer dropwise into the reaction vessel, controlling the dropping rate to 1-2 drops / second, while maintaining the temperature during this period;

[0022] S13. After the addition is complete, raise the temperature to 80-100℃ and keep it warm for 2-4 hours to mature;

[0023] S14. Cool and filter the matured product to obtain intermediate A.

[0024] Preferably, step S3 specifically includes the following sub-steps:

[0025] S31. Cool the amine salt generated in step S2 to 40-50℃;

[0026] S32. While stirring, slowly add intermediate A obtained in step S1 to the amine salt, controlling the addition time to be 20-40 minutes;

[0027] S33. After the addition is complete, heat the system to 75-85℃ and react for 2-3 hours;

[0028] S34. After the reaction is complete, the product is cooled to obtain the modified amine salt.

[0029] Preferably, in step S32, the weight ratio of intermediate A to amine salt is 1:5 to 1:10.

[0030] Preferably, the catalyst in step S11 is p-toluenesulfonic acid or concentrated sulfuric acid.

[0031] Preferably, the modified monomer in step S12 is at least one of itaconic acid, hydroxyethyl acrylate, or maleic anhydride.

[0032] Preferably, in step S4, the stirring speed is 300-500 rpm and the stirring time is 30-60 minutes.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] By introducing a specially prepared intermediate A to modify traditional amine salts at the molecular level, the film-forming properties and adhesion strength of the corrosion inhibitor are significantly improved. Intermediate A, as a functional polymer, can graft copolymerize with the amine salt to form a dense, stable, and hydrophobic protective film on the metal surface. This film can more effectively block the contact between corrosive media and the metal substrate, thereby increasing the corrosion inhibition efficiency from approximately 70% of ordinary amine salts to over 90%, achieving highly efficient protection.

[0035] By scientifically combining modified amine salts, metal passivators, and dispersants, a remarkable synergistic effect is achieved among the components. The modified amine salts, acting as the main film-forming agent, construct a macroscopic barrier, while the metal passivators preferentially adsorb onto metal active sites, inhibiting localized corrosion. The dispersants not only ensure the product's uniform stability during storage but also promote the uniform dispersion and targeted delivery of active ingredients during application, ensuring their rapid arrival at the metal surface and full effectiveness. Together, they construct a multi-layered, comprehensive, three-dimensional protective system.

[0036] The final product of this invention can precisely cope with the complex and harsh corrosive environment of the top of the atmospheric and vacuum distillation tower in oil refining units. It not only solves the industry pain points of insufficient efficiency and unstable protective film of traditional water-soluble corrosion inhibitors, but also, due to its excellent water solubility and stability, facilitates on-site dilution and precise injection, making operation simple and providing reliable technical support for the long-term safe operation and cost reduction and efficiency improvement of oil refining units. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the preparation method of the present invention;

[0038] Figure 2 This is a sub-step of step S1 in the preparation method of the present invention;

[0039] Figure 3 This is a sub-step of step S3 in the preparation method of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] like Figure 1-3 As shown:

[0042] Example 1

[0043] 1. Formula (parts by weight):

[0044] Organic amine compound (cyclohexylamine): 20 parts; organic acid (lauric acid): 15 parts; surfactant (sodium dodecylbenzenesulfonate): 5 parts; solvent (deionized water): 30 parts; metal passivating agent (benzotriazole): 1 part; dispersing aid (polyvinylpyrrolidone): 0.5 parts;

[0045] 2. Preparation method:

[0046] Step S1: Add 2 parts of p-toluenesulfonic acid catalyst to the reaction vessel and preheat to 50°C. Slowly add 10 parts of modified monomer itaconic acid dropwise at a rate of 1 drop / second, maintaining the temperature throughout. After the addition is complete, raise the temperature to 80°C and maintain the temperature for 2 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0047] Step S2: React 20 parts of cyclohexylamine with 15 parts of lauric acid at 60°C for 1 hour to generate an amine salt.

[0048] Step S3: Cool the amine salt from step S2 to 40°C. While stirring, slowly add all of intermediate A obtained in step S1, controlling the addition time to 20 minutes. Then raise the temperature to 75°C and react for 2 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0049] Step S4: Add 5 parts sodium dodecylbenzenesulfonate, 1 part benzotriazole and 0.5 parts polyvinylpyrrolidone to 30 parts deionized water, and stir at 300 rpm for 30 minutes at 40°C to obtain mixture B.

[0050] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm for 1 hour at 50°C, and cool to room temperature to obtain the final corrosion inhibitor product.

[0051] Example 2

[0052] 1. Formula (parts by weight):

[0053] Organic amine compound (diethanolamine): 30 parts; organic acid (oleic acid): 22.5 parts; surfactant (fatty alcohol polyoxyethylene ether): 10 parts; solvent (1:1 mixture of deionized water and ethanol): 40 parts; metal passivating agent (methylbenzotriazole): 3 parts; dispersing aid (sodium polyacrylate): 1.75 parts;

[0054] 2. Preparation method:

[0055] Step S1: Add concentrated sulfuric acid (2.5 parts) to the reaction vessel and preheat to 60°C. Slowly add the modified monomer hydroxyethyl acrylate (15 parts) dropwise, controlling the dropping rate at 1.5 drops / second, while maintaining the temperature. After the addition is complete, raise the temperature to 90°C and maintain the temperature for 3 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0056] Step S2: React 30 parts of diethanolamine with 22.5 parts of oleic acid at 70°C for 1.5 hours to generate an amine salt.

[0057] Step S3: Cool the amine salt from Step S2 to 45°C. While stirring, slowly add intermediate A obtained in Step S1 (the amount added is 1 / 7.5 of the weight of the amine salt, within the range of 1:5 to 1:10), controlling the addition time to 30 minutes. Then raise the temperature to 80°C and react for 2.5 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0058] Step S4: Add 10 parts of fatty alcohol polyoxyethylene ether, 3 parts of methylbenzotriazole and 1.75 parts of sodium polyacrylate to 40 parts of mixed solvent, and stir at 400 rpm for 45 minutes at 50°C to obtain mixture B.

[0059] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm for 2 hours at 60°C, and cool to room temperature to obtain the final corrosion inhibitor product.

[0060] Example 3

[0061] 1. Formula (parts by weight):

[0062] Organic amine compound (triethanolamine): 40 parts; Organic acid (aminotrimethylenephosphonic acid): 30 parts; Surfactant (alkylphenol polyoxyethylene ether): 15 parts; Solvent (isopropanol): 50 parts; Metal passivator (thiadiazole derivative): 5 parts; Dispersant (hydroxymethyl cellulose): 3 parts.

[0063] 2. Preparation method:

[0064] Step S1: Add 3 parts of p-toluenesulfonic acid catalyst to the reaction vessel and preheat to 70°C. Slowly add 20 parts of modified monomer maleic anhydride at a dropping rate of 2 drops / second, maintaining the temperature throughout. After the addition is complete, raise the temperature to 100°C and maintain the temperature for 4 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0065] Step S2: React 40 parts of triethanolamine with 30 parts of aminotrimethylenephosphonic acid at 80°C for 2 hours to generate an amine salt.

[0066] Step S3: Cool the amine salt from step S2 to 50°C. While stirring, slowly add intermediate A obtained in step S1 (1 / 10 of the weight of the amine salt), controlling the addition time to 40 minutes. Then raise the temperature to 85°C and react for 3 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0067] Step S4: Add 15 parts alkylphenol polyoxyethylene ether, 5 parts thiadiazole derivative and 3 parts hydroxymethyl cellulose to 50 parts isopropanol, and stir at 500 rpm for 60 minutes at 60°C to obtain mixture B.

[0068] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm for 3 hours at 70°C, and cool to room temperature to obtain the final corrosion inhibitor product.

[0069] Example 4

[0070] Formula (parts by weight):

[0071] Organic amine compound (morpholine): 25 parts; Organic acid (citric acid): 18 parts; Surfactant (sodium dodecyl sulfate): 8 parts; Solvent (ethanol): 35 parts; Metal passivator (benzotriazole): 2 parts; Dispersant (hydroxymethyl cellulose): 1 part;

[0072] Preparation method:

[0073] Step S1: Add 2.2 parts of p-toluenesulfonic acid catalyst to the reaction vessel and preheat to 55°C. Slowly add 12 parts of modified monomer itaconic acid dropwise at a rate of 1 drop / second, maintaining the temperature throughout. After the addition is complete, raise the temperature to 85°C and maintain the temperature for 2.5 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0074] Step S2: React 25 parts of morpholine with 18 parts of citric acid at 65°C for 1.2 hours to generate an amine salt.

[0075] Step S3: Cool the amine salt from Step S2 to 42°C. While stirring, slowly add intermediate A obtained in Step S1 (1 / 6 of the weight of the amine salt), controlling the addition time to 25 minutes. Then raise the temperature to 78°C and react for 2.2 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0076] Step S4: Add 8 parts sodium dodecyl sulfate, 2 parts benzotriazole and 1 part hydroxymethyl cellulose to 35 parts ethanol, and stir at 350 rpm for 40 minutes at 45°C to obtain mixture B.

[0077] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm for 1.5 hours at 55°C, and cool to room temperature to obtain the final corrosion inhibitor product.

[0078] Example 5

[0079] Formula (parts by weight):

[0080] Organic amine compounds (a mixture of cyclohexylamine and diethanolamine, in a mass ratio of 1:1): 28 parts; organic acids (a mixture of lauric acid and oleic acid, in a mass ratio of 1:1): 20 parts; surfactants (a mixture of fatty alcohol polyoxyethylene ether and sodium dodecylbenzenesulfonate, in a mass ratio of 1:1): 9 parts; solvents (a mixture of deionized water and isopropanol, in a mass ratio of 1:1): 38 parts; metal passivating agent (methylbenzotriazole): 2.5 parts; dispersing agent (a mixture of polyvinylpyrrolidone and sodium polyacrylate, in a mass ratio of 1:1): 1.5 parts;

[0081] Preparation method:

[0082] Step S1: Add concentrated sulfuric acid (2.3 parts) to the reaction vessel and preheat to 65°C. Slowly add a mixture of modified monomers, hydroxyethyl acrylate and maleic anhydride (mass ratio 1:1, total 14 parts), controlling the dropping rate at 1.5 drops / second, while maintaining the temperature. After the addition is complete, raise the temperature to 88°C and maintain it for 3 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0083] Step S2: React 28 parts of mixed organic amines with 20 parts of mixed organic acids at 68°C for 1.5 hours to generate amine salts.

[0084] Step S3: Cool the amine salt from Step S2 to 44°C. While stirring, slowly add intermediate A obtained in Step S1 (1 / 8 the weight of the amine salt), controlling the addition time to 28 minutes. Then raise the temperature to 79°C and react for 2.5 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0085] Step S4: Add 9 parts of mixed surfactant, 2.5 parts of methylbenzotriazole and 1.5 parts of mixed dispersant to 38 parts of mixed solvent, and stir at 380 rpm for 50 minutes at 48°C to obtain mixture B.

[0086] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm for 1.8 hours at 58°C, and cool to room temperature to obtain the final corrosion inhibitor product.

[0087] Example 6

[0088] Formula (parts by weight):

[0089] Organic amine compounds (morpholine and triethanolamine, mass ratio 1:2): 32 parts; organic acids (oleic acid and aminotrimethylenephosphonic acid, mass ratio 2:1): 24 parts; surfactants (alkylphenol polyoxyethylene ether): 11 parts; solvents (deionized water, ethanol and isopropanol, mass ratio 1:1:1): 42 parts; metal passivating agents (thiadiazole derivatives): 3.5 parts; dispersing aids (sodium polyacrylate): 2 parts;

[0090] Preparation method:

[0091] Step S1: Add 2.7 parts of p-toluenesulfonic acid catalyst to the reaction vessel and preheat to 58°C. Slowly add a mixture of modified monomers itaconic acid and hydroxyethyl acrylate (mass ratio 1:1, total 16 parts) dropwise, controlling the dropping rate at 1.2 drops / second, while maintaining the temperature. After the addition is complete, raise the temperature to 92°C and maintain it for 3.5 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0092] Step S2: React 32 parts of mixed organic amines with 24 parts of mixed organic acids at 72°C for 1.7 hours to generate amine salts.

[0093] Step S3: Cool the amine salt from Step S2 to 47°C. While stirring, slowly add intermediate A obtained in Step S1 (1 / 9 the weight of the amine salt), controlling the addition time to 35 minutes. Then raise the temperature to 82°C and react for 2.7 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0094] Step S4: Add 11 parts alkylphenol polyoxyethylene ether, 3.5 parts thiadiazole derivative and 2 parts sodium polyacrylate to 42 parts mixed solvent, and stir at 52°C and 420 rpm for 55 minutes to obtain mixture B.

[0095] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm for 2.2 hours at 65°C, and cool to room temperature to obtain the final corrosion inhibitor product.

[0096] Example 7

[0097] Formula (parts by weight):

[0098] Organic amine compound (diethanolamine): 35 parts; organic acid (citric acid and lauric acid mixed, mass ratio 1:1): 26 parts; surfactant (sodium dodecyl sulfate and fatty alcohol polyoxyethylene ether mixed, mass ratio 1:2): 12 parts; solvent (isopropanol): 45 parts; metal passivating agent (benzotriazole and methylbenzotriazole mixed, mass ratio 1:1): 4 parts; dispersing agent (polyvinylpyrrolidone and carboxymethyl cellulose mixed, mass ratio 1:1): 2.2 parts;

[0099] Preparation method:

[0100] Step S1: Add concentrated sulfuric acid (2.8 parts) to the reaction vessel and preheat to 62°C. Slowly add the modified monomer maleic anhydride (18 parts) dropwise, controlling the dropping rate at 1.8 drops / second, while maintaining the temperature. After the addition is complete, raise the temperature to 95°C and maintain it for 3.2 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0101] Step S2: React 35 parts of diethanolamine with 26 parts of mixed organic acid at 75°C for 1.8 hours to generate amine salt.

[0102] Step S3: Cool the amine salt from Step S2 to 48°C. While stirring, slowly add intermediate A obtained in Step S1 (the amount added is 1 / 7.5 of the weight of the amine salt), controlling the addition time to 32 minutes. Then raise the temperature to 81°C and react for 2.8 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0103] Step S4: Add 12 parts of mixed surfactant, 4 parts of mixed metal passivator and 2.2 parts of mixed dispersant to 45 parts of isopropanol, and stir at 55°C and 450 rpm for 58 minutes to obtain mixture B.

[0104] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm at 68°C for 2.5 hours, and cool to room temperature to obtain the final corrosion inhibitor product.

[0105] Example 8

[0106] Formula (parts by weight):

[0107] Organic amine compounds (a mixture of cyclohexylamine, morpholine, and triethanolamine, in a mass ratio of 1:1:1): 38 parts; organic acids (a mixture of aminotrimethylenephosphonic acid and oleic acid, in a mass ratio of 1:1): 28 parts; surfactants (a mixture of sodium dodecylbenzenesulfonate, alkylphenol polyoxyethylene ether, and sodium dodecyl sulfate, in a mass ratio of 1:1:1): 13 parts; solvents (a mixture of deionized water and ethanol, in a mass ratio of 2:1): 48 parts; metal passivating agents (a mixture of benzotriazole, methylbenzotriazole, and thiadiazole derivatives, in a mass ratio of 1:1:1): 4.5 parts; dispersing aids (a mixture of polyvinylpyrrolidone, sodium polyacrylate, and carboxymethyl cellulose, in a mass ratio of 1:1:1): 2.8 parts;

[0108] Preparation method:

[0109] Step S1: Add 2.9 parts of p-toluenesulfonic acid catalyst to the reaction vessel and preheat to 68°C. Slowly add a mixture of modified monomers itaconic acid, hydroxyethyl acrylate, and maleic anhydride (mass ratio 1:1:1, total 19 parts) at a dropping rate of 2 drops / second, maintaining the temperature throughout. After the addition is complete, raise the temperature to 98°C and maintain it for 3.8 hours. Cool the product to room temperature, filter, and obtain intermediate A.

[0110] Step S2: React 38 parts of mixed organic amines with 28 parts of mixed organic acids at 78°C for 1.9 hours to generate amine salts.

[0111] Step S3: Cool the amine salt from Step S2 to 49°C. While stirring, slowly add intermediate A obtained in Step S1 (1 / 9.5 of the weight of the amine salt), controlling the addition time to 38 minutes. Then raise the temperature to 84°C and react for 2.9 hours. After the reaction is complete, cool to obtain the modified amine salt.

[0112] Step S4: Add 13 parts of mixed surfactant, 4.5 parts of mixed metal passivator and 2.8 parts of mixed dispersant to 48 parts of mixed solvent, and stir at 58°C and 480 rpm for 65 minutes to obtain mixture B.

[0113] Step S5: Mix the modified amine salt obtained in step S3 with the mixture B obtained in step S4, stir continuously at 400 rpm at 69°C for 2.8 hours, and cool to room temperature to obtain the final corrosion inhibitor product.

[0114] Experimental Example: Performance Comparison Test of High-Efficiency Water-Soluble Corrosion Inhibitors

[0115] 1. Experimental Objective

[0116] This experiment aims to compare the corrosion inhibition performance of the corrosion inhibitor described in this invention with that of corrosion inhibitors lacking key components or using conventional formulations by simulating the operating conditions at the top of an atmospheric and vacuum distillation tower in an oil refining unit.

[0117] 2. Experimental Design

[0118] 2.1 Samples and Materials

[0119] Hanging plate: Standard 20# carbon steel hanging plate (size: 50mm×25mm×2mm)

[0120] Medium: Simulated condensate from the top of an atmospheric and vacuum distillation tower in an oil refinery (Preparation method: Add 1000 mg / L L⁻(NaCl) and 500 mg / L L²⁻(Na₂S·9H₂O) to deionized water, and adjust the pH to 4.0-5.0 with dilute sulfuric acid).

[0121] Experimental temperature: 50±2℃

[0122] Ventilation: A small amount of air (or a mixture of nitrogen and carbon dioxide) is continuously introduced to simulate a corrosive environment.

[0123] Experiment duration: 72 hours

[0124] 2.2 Test Grouping

[0125] The experiment consisted of 5 groups, including 1 control group and 4 comparative groups.

[0126] Group describe Purpose Reference group Example 2: The corrosion inhibitor obtained by the formulation and preparation method was added at a dosage of 100 mg / L. As a performance benchmark Comparative Example 1 It does not contain intermediate A (i.e., steps S1 and S3 are not performed, and only the common amine salt generated by S2 is used). The key role of verifying the modification of intermediate A Comparative Example 2 Free of metal passivators (benzotriazole is removed from the formulation). Verify the necessity of metal passivating agents Comparative Example 3 Free of dispersants (sodium polyacrylate is removed from the formulation). Verify the effect of dispersants on system stability and synergistic effect. Blank group No corrosion inhibitors added Provide a reference for the basic corrosion rate

[0127] 2.3 Experimental Procedure

[0128] Pretreatment of hanging plates: The carbon steel hanging plates are successively sanded with sandpaper (180# to 800#), dehydrated with anhydrous ethanol, cleaned with acetone, and dried with cold air. They are then weighed (recorded as M1) using an electronic analytical balance (accuracy 0.1mg) and their dimensions are measured.

[0129] Experimental procedure: 2000 mL of simulated medium was added to each reactor, and the temperature was raised to 50°C. Corrosion inhibitors of the appropriate type and dosage were added according to the group requirements. The treated plates were suspended in the medium using nylon ropes, and timing was started while gas was continuously introduced.

[0130] Post-treatment: After 72 hours, remove the pads and, referring to standard GB / T18590-2001, remove the corrosion products on the surface of the pads with a special pickling solution (such as inhibited HCl). After dehydration and drying with anhydrous ethanol, weigh them again (recorded as M2).

[0131] 3. Experimental Results and Data Analysis

[0132] 3.1 Experimental Data Recording Table

[0133] Group <![CDATA[Initial weight M1 (g)]]> <![CDATA[Final weight M2 (g)]]> Weight loss ΔM(g) Corrosion rate (mm / a) Corrosion inhibition rate Blank group 19.5432 19.4015 0.1417 1.205 - Reference group (Example 2) 19.6218 19.6083 0.0135 0.115 90.5% Comparative Example 1 (without intermediate A) 19.5874 19.5491 0.0383 0.326 73.0% Comparative Example 2 (without metal passivator) 19.5541 19.5256 0.0285 0.243 79.8% Comparative Example 3 (without dispersant) 19.5995 19.5712 0.0283 0.241 80.0%

[0134] Note: Corrosion rate calculation formula (based on weight loss method): Corrosion Rate (mm / a) = (ΔM × 8.76 × 10) 4 ) / (A·t·D), where A is the area (cm²), t is the time (h), and D is the material density (g / cm³). Corrosion inhibition rate η = (V0-V) / V0×100%, where V0 is the corrosion rate of the blank group and V is the corrosion rate of the chemical-treated group.

[0135] 3.2 Results Analysis

[0136] Overall validity verification:

[0137] The corrosion inhibition rate of the control group (Example 2) was as high as 90.5%, and the corrosion rate was much lower than that of the blank group, which fully demonstrates that the corrosion inhibitor formulation provided by the present invention has excellent corrosion inhibition performance under simulated working conditions.

[0138] Analysis of the role of key components:

[0139] The key role of intermediate A (Comparative Example 1 vs. Control Group): The corrosion inhibition rate of Comparative Example 1 (without intermediate A modification) (73.0%) was significantly lower than that of the control group (90.5%). This indicates that the corrosion inhibition performance of ordinary amine salts is limited, while the modification of amine salts by intermediate A prepared in steps S1 and S3 greatly improves the film-forming properties and protective effect of the corrosion inhibitor.

[0140] The necessity of metal passivators (Comparative Example 2 vs. Control Group): The corrosion inhibition rate of Comparative Example 2 (without metal passivator) (79.8%) was significantly lower than that of the control group. This indicates that in acidic and complex media containing sulfur and chloride ions, a single adsorption-type corrosion inhibitor (modified amine salt) is insufficient to completely suppress corrosion. Metal passivators can effectively complex metal ions, forming a dense protective film on the metal surface, and producing a significant synergistic effect with organic corrosion inhibitors.

[0141] Function of dispersant (Comparative Example 3 vs. Control Group): The corrosion inhibition rate (80.0%) of Comparative Example 3 (without dispersant) was also lower than that of the control group. This indicates that the dispersant not only ensures the storage stability of the product, but may also promote the uniform dispersion of each effective component in the corrosive medium during application, allowing it to reach the metal surface more effectively, thereby enhancing the overall synergistic effect.

[0142] This invention uses modified amine salts as the main film-forming agent, metal passivators to provide auxiliary protection, and dispersants to ensure system stability and efficient component transport. These three components form a synergistic whole. The absence of any one of these components will lead to a significant decrease in corrosion inhibition performance.

[0143] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0144] The accompanying drawings of the embodiments disclosed in this invention only involve structures relevant to the embodiments disclosed in this invention. Other structures can be referred to with common designs. Unless otherwise specified, the same embodiment and different embodiments of this invention can be combined with each other.

[0145] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high efficiency water soluble corrosion inhibitor for oil refining units, characterized in that, Prepared from raw materials comprising the following components by weight: Organic amine compound 20-40 parts; organic acid 15-30 parts; surfactant 5-15 parts; solvent 30-50 parts; metal passivator 1-5 parts; dispersion aid 0.5-3 parts.

2. The high-efficiency water-soluble corrosion inhibitor according to claim 1, characterized in that: The organic amine compound is at least one of morpholine, cyclohexylamine, diethanolamine, and triethanolamine; The organic acid is at least one of lauric acid, oleic acid, citric acid, and amino-trimethylene phosphonic acid; The solvent is at least one of deionized water, ethanol, and isopropanol.

3. The high-efficiency water-soluble corrosion inhibitor according to claim 1, characterized in that: The surfactant is at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, sodium dodecyl benzene sulfonate, or sodium dodecyl sulfate; The metal passivator is at least one of benzotriazole, methyl benzotriazole, or thiazole derivative; The dispersion aid is at least one of polyvinylpyrrolidone, sodium polyacrylate, or hydroxymethyl cellulose.

4. A process for the preparation of the high efficiency water soluble corrosion inhibitor as claimed in any one of claims 1 to 3, wherein, Comprising the following steps: S1. Reacting the modified monomer at 50-100°C in the presence of a catalyst to prepare intermediate A; S2. Reacting the organic amine compound with the organic acid at 60-80°C for 1-2 hours to form an amine salt; S3. Modifying the amine salt formed in step S2 using the intermediate A prepared in step S1 to obtain a modified amine salt; S4. Adding the surfactant, metal passivator, and dispersion aid to the solvent, stirring and dissolving at 40-60°C to obtain a mixed solution B; S5. Mixing the modified amine salt obtained in step S3 with the mixed solution B obtained in step S4, continuously stirring at 50-70°C for 1-3 hours, and cooling to room temperature to obtain the high-efficiency water-soluble corrosion inhibitor.

5. The method of claim 4, wherein, The step S1 specifically comprises the following sub-steps: S11. Adding the catalyst to the reaction container and preheating to 50-70°C; S12. Slowly adding the modified monomer to the reaction container, controlling the drop rate at 1-2 drops per second, and maintaining the temperature during the process; S13. After the addition is completed, increasing the temperature to 80-100°C, and incubating for 2-4 hours; S14. Cooling and filtering the incubated product to obtain the intermediate A.

6. The method of claim 5, wherein, The step S3 specifically comprises the following sub-steps: S31. Cooling the amine salt formed in step S2 to 40-50°C; S32. Slowly adding the intermediate A prepared in step S1 to the amine salt under stirring, controlling the addition time at 20-40 minutes; S33. After the addition is completed, increasing the temperature of the system to 75-85°C, and reacting for 2-3 hours; S34. After the reaction is completed, cooling the product to obtain the modified amine salt.

7. The method of claim 6, wherein, In the step S32, the weight ratio of intermediate A to amine salt is 1:5 to 1:

10.

8. The method of claim 5, wherein, The catalyst in the step S11 is p-toluenesulfonic acid or concentrated sulfuric acid.

9. The method of claim 5, wherein, The modified monomer in the step S12 is at least one of itaconic acid, hydroxyethyl acrylate, or maleic anhydride.

10. The method of claim 4, wherein, In the step S4, the stirring speed is 300-500 rpm, and the stirring time is 30-60 minutes.

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