A triazine-based high-temperature CO2 corrosion inhibitor and preparation method thereof

Abstract

The invention provides a triazine-based high-temperature CO2 corrosion inhibitor and a preparation method thereof, belonging to the technical field of corrosion-inhibiting compositions and corrosion inhibitors. In terms of weight percentage, the triazine-based high-temperature CO2 corrosion inhibitor comprises 10%-50% of s-triazine derivatives, 3%-16% of C2-C4 alkynols, 4%-10% of C 12 ‑C 18 Alkane acid, 0%-15% surfactant, 20%-40% organic solvent, and 0%-40% water, totaling 100%; wherein the triazine-based high-temperature CO2 corrosion inhibitor is suitable for resisting CO2 corrosion at high temperatures of 60℃-120℃, and the s-triazine derivative has a structure shown in formula (I): #imgabs0# Formula (1).

Description

Technical Field

[0001] The present invention belongs to the technical field of corrosion-inhibiting compositions and corrosion inhibitors, and in particular, relates to a triazine-based high-temperature CO2 corrosion inhibitor and a preparation method thereof, and more specifically, relates to a triazine-based high-temperature CO2 corrosion inhibitor capable of resisting CO2 corrosion to carbon steel and a preparation method thereof. Background Art

[0002] Carbon dioxide (CO2) is a component of natural gas or associated gas and exists in oil and gas. CO2 is highly corrosive to steel when dissolved in water. At the same pH value, CO2 is more corrosive to steel than hydrochloric acid. In terms of oil and gas exploration and development, the water content and temperature inside oil and gas wells are getting higher and higher as they enter the middle and late stages of production, and the corrosion problem of carbon steel pipelines is becoming increasingly prominent. Existing steel materials cannot meet the requirements of corrosion protection under high temperature and high pressure (80°C, above 1MPa), and the CO2 corrosion problem is more prominent under high temperature (above 80°C), so temperature influence is taken as the main consideration in various CO2 corrosion models. At present, there are many studies on room temperature (25°C) CO2 corrosion inhibitors, including imidazolines, Schiff bases, organic amines, quaternary ammonium salts, natural extracts and other corrosion inhibitors. These corrosion inhibitors can effectively prevent corrosion at room temperature; but after exceeding 80°C, the corrosion inhibition rate drops significantly and cannot meet industrial applications. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a triazine-based high-temperature CO2 corrosion inhibitor and a preparation method thereof, in order to at least partially solve the above technical problems. In this regard, the technical solution provided by the present invention is as follows.

[0004] As a first aspect of the present invention, a triazine-based high temperature CO2 corrosion inhibitor is provided, which comprises, by weight percentage, 10%-50% of a s-triazine derivative, 3%-16% of a C2-C4 alkynol, 4%-10% of a C 12 -C 18 Alkyl acid, 0%-15% surfactant, 20%-40% organic solvent, and 0%-40% water, totaling 100%; wherein the triazine-based high-temperature CO2 corrosion inhibitor is suitable for resisting CO2 corrosion at high temperatures of 60°C-120°C, and the s-triazine derivative has a structure as shown in formula (1): Formula (1).

[0005] As a second aspect of the present invention, a method for preparing a triazine-based high-temperature CO2 corrosion inhibitor is provided, comprising: uniformly mixing trichlorotriazine and diallylamine in a solvent, adding an alkaline reagent for initiation, and then heating and stirring the mixture to obtain an s-triazine derivative; and mixing, by weight percentage, 10%-50% of the s-triazine derivative, 3%-16% of a C2-C4 alkynol, and 4%-10% of a C 12 -C 18 Alkyl acid, 0%-15% of a surfactant, 20%-40% of an organic solvent, and 0%-40% of water are mixed, totaling 100%, to obtain a triazine-based high-temperature CO2 corrosion inhibitor.

[0006] In the embodiment of the present invention, the triazine-based high temperature CO2 corrosion inhibitor of the present invention mainly includes s-triazine derivatives, C2-C4 alkynols, C 12 -C 18 Alkyl acid and organic solvent, wherein the multiple nitrogen (N) sites and double bonds contained in s-triazine derivatives can increase the binding energy between triazine-based high-temperature CO2 corrosion inhibitor and metal iron (Fe) atoms in carbon steel, making the binding stronger and adsorbing the triazine-based high-temperature CO2 corrosion inhibitor firmly on the metal surface. Furthermore, because s-triazine derivatives have large molecules and gaps between them, they are more susceptible to corrosion, while the molecular structure of C2-C4 alkynols is smaller, and C2-C4 alkynols can fill the gaps between s-triazine derivatives, thereby forming a denser covering film, so that the triazine-based high-temperature CO2 corrosion inhibitor obtains a higher corrosion inhibition rate when the temperature is higher than 60°C or 80°C. Introducing C2-C4 alkynol into triazine-based high-temperature CO2 corrosion inhibitor 12 -C 18 Alkyl acid can form a hydrophobic protective layer on the surface of carbon steel to prevent the metal from being corroded by water and CO2, thereby obtaining a higher corrosion inhibition rate and more effectively preventing corrosion. The introduction of an organic solvent or the simultaneous introduction of a surfactant and an organic solvent facilitates the dissolution of some water-insoluble substances in the triazine-based high-temperature CO2 corrosion inhibitor in water, improves the solubility, wettability and adsorption of the triazine-based high-temperature CO2 corrosion inhibitor, and accelerates the triazine-based high-temperature CO2 corrosion inhibitor to exert its corrosion inhibition effect. In addition, the triazine-based high-temperature CO2 corrosion inhibitor of the present invention is used in a small amount, and the preparation method of the triazine-based high-temperature CO2 corrosion inhibitor is relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A The actual pictures are of the untested steel sheet 1723 and the steel sheet 1723 without using the corrosion inhibitor;

[0008] Figure 1B The actual pictures are of the untested steel sheet 1061 and the steel sheet 1061 using the corrosion inhibitor in Example 2;

[0009] Figure 2are scanning electron microscope (SEM) images of different steel sheets, wherein a is the SEM image of the untested steel sheet 1723, b is the SEM image of the steel sheet 1723 without using the corrosion inhibitor, and c is the SEM image of the steel sheet 1061 using the corrosion inhibitor in Example 2. DETAILED DESCRIPTION

[0010] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0011] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0012] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0013] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0014] In view of the problem that the corrosion inhibition rate of current corrosion inhibitors decreases significantly when used in a CO2 environment above 80°C, the present invention provides a new triazine-based high-temperature CO2 corrosion inhibitor suitable for high-temperature, high-pressure (60°C-120°C, 2MPa), high mineralization (higher than 25000mg / L) and CO2-rich environment and a preparation method thereof. Diallylamine and s-triazine are reacted to form s-triazine derivatives, and the multiple N sites and double bonds contained in the s-triazine derivatives are utilized to increase the binding ability between the triazine-based high-temperature CO2 corrosion inhibitor and the metal, so that the triazine-based high-temperature CO2 corrosion inhibitor is fixedly adsorbed on the metal surface, thereby achieving the purpose of delaying the corrosion of the metal by water and CO2.

[0015] Specifically, as a first aspect of the present invention, a triazine-based high-temperature CO2 corrosion inhibitor is provided, which comprises, by weight percentage, 10%-50% of a s-triazine derivative, 3%-16% of a C2-C4 alkynol, 4%-10% of a C 12 -C 18 Alkyl acid, 0%-15% surfactant, 20%-40% organic solvent, and 0%-40% water, totaling 100%; wherein the triazine-based high-temperature CO2 corrosion inhibitor is suitable for resisting CO2 corrosion at high temperatures of 60°C-120°C, and the s-triazine derivative has a structure as shown in formula (1): Formula (1).

[0016] In the embodiment of the present invention, the corrosion inhibitor forms a coating on the metal surface of carbon steel, thereby reducing the corrosion rate of CO2 and water on the metal in carbon steel. The triazine-based high-temperature CO2 corrosion inhibitor in the present invention mainly includes s-triazine derivatives, C2-C4 alkynols, C 12 -C 18 Alkyl acid and organic solvent. Among them, the multiple N sites and double bonds contained in s-triazine derivatives can increase the binding energy between the triazine-based high-temperature CO2 corrosion inhibitor and the metallic iron (Fe) atoms in carbon steel, so that the triazine-based high-temperature CO2 corrosion inhibitor can be firmly adsorbed on the metal surface after forming a covering film, thereby reducing the metal corrosion rate. Furthermore, because the molecules of s-triazine derivatives are large and there are gaps between them, they are more easily corroded, and the molecular structure of C2-C4 alkynols is small. Therefore, C2-C4 alkynols can fill the gaps between s-triazine derivatives, thereby forming a denser covering film, so that the triazine-based high-temperature CO2 corrosion inhibitor can obtain a higher corrosion inhibition rate in an environment rich in CO2 at a temperature above 60°C or 80°C, and more effectively prevent corrosion. Introducing C2-C4 alkynols into triazine-based high-temperature CO2 corrosion inhibitors 12 -C 18Alkyl acid can form a hydrophobic protective layer on the metal surface of carbon steel to prevent the metal from being corroded by water, thereby obtaining a higher corrosion inhibition rate. In addition, because there are some substances that are difficult to dissolve in water in triazine-based high-temperature CO2 corrosion inhibitors, these substances that are difficult to dissolve in water are not conducive to the corrosion inhibition performance. By introducing organic solvents, or introducing organic solvents and surfactants at the same time, these insoluble substances can be promoted to dissolve in water, thereby improving the solubility, wettability and adsorption of triazine-based high-temperature CO2 corrosion inhibitors, so as to accelerate the corrosion inhibition of triazine-based high-temperature CO2 corrosion inhibitors. Among them, the surfactant contains a hydrophilic group, which can reduce the surface tension of the triazine-based high-temperature CO2 corrosion inhibitor, making it easier to dissolve in water and easy to wet the metal surface, which is beneficial to improve the solubility and wettability of the triazine-based high-temperature CO2 corrosion inhibitor; the benzenesulfonic acid group or sulfate group rich in electron cloud in the surfactant forms a chemical bond and / or physical adsorption with the metal surface, and after compounding with s-triazine derivatives, the adsorption amount of triazine-based high-temperature CO2 corrosion inhibitor on the metal surface can be increased, thereby also improving the corrosion inhibition effect. The presence of organic solvent can promote the dissolution of triazine-based high-temperature CO2 corrosion inhibitor, thereby accelerating the effect of triazine-based high-temperature CO2 corrosion inhibitor.

[0017] According to an embodiment of the present invention, the surfactant may not be added; the surfactant and the organic solvent may also be used simultaneously and combined with the s-triazine derivative, C2-C4 alkynol and C 12 -C 18 Alkane acid is compounded.

[0018] According to an embodiment of the present invention, the organic solvent is selected from any one of methanol, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide. The surfactant is selected from any one of sodium dodecylbenzene sulfonate and sodium dodecyl sulfate.

[0019] According to an embodiment of the present invention, the triazine-based high-temperature CO2 corrosion inhibitor is generally used after being mixed with water. After adding water, the triazine-based high-temperature CO2 corrosion inhibitor is easier to operate and can improve work efficiency.

[0020] According to an embodiment of the present invention, preferably, the triazine-based high temperature CO2 corrosion inhibitor comprises: 40%-50% of s-triazine derivatives, 3%-10% of C2-C4 acetylenic alcohols, 5%-12% of surfactants, 4%-8% of C 12 -C 18 Alkanoic acid, 20%-30% organic solvent and 10%-20% water, totaling 100%.

[0021] According to an embodiment of the present invention, the s-triazine derivative is obtained by reacting trichlorotriazine and diallylamine.

[0022] In an embodiment of the present invention, diallylamine is used as a monomer to react with trichlorotriazine to prepare s-triazine derivatives, wherein the steric hindrance of diallylamine is small, the reaction is easier to carry out and the yield is higher. In addition, the two allyl groups provide N sites, making it easier for N to undergo nucleophilic substitution reaction with the carbon (C) connected to the chlorine group in trichlorotriazine, which facilitates the occurrence of the reaction. As for phenylcyclic amine and pyridine cyclic amine, the steric hindrance of these compounds is large, the reaction barrier is large, the reaction is not easy to carry out and the yield is low. In addition, diallylamine has more double bonds than propyl, ethyl and other alkanes, and the double bonds can be bonded to the 3d empty orbital of metal Fe in carbon steel, so that the triazine-based high-temperature CO2 corrosion inhibitor is firmly combined at high temperatures (60°C-120°C).

[0023] According to an embodiment of the present invention, the C2-C4 alkynol is selected from a C2-C4 monoalkynol or a C4 dialkynol. More specifically, the C2-C4 alkynol is selected from any one of 1,4-butyn-diol, 3-butyn-1-ol, acetylene alcohol, and propargyl alcohol. 12 -C 18 The alkanoic acid is selected from any one of dodecanoic acid, pentadecanoic acid, hexadecanoic acid and octadecanoic acid.

[0024] In the embodiments of the present invention, compared with the s-triazine derivatives, the molecular structure of C2-C4 alkynol is smaller, and it can be inserted into the gaps between the s-triazine derivatives. The triazine-based high-temperature CO2 corrosion inhibitor formed can form a denser covering film on the metal surface to shield CO2 corrosion. 12 -C 18 Alkanoic acid can form a hydrophobic protective layer and can also improve the corrosion inhibition rate of triazine-based high-temperature CO2 corrosion inhibitor.

[0025] As a second aspect of the present invention, a method for preparing a triazine-based high-temperature CO2 corrosion inhibitor is provided, comprising: uniformly mixing trichlorotriazine and diallylamine in a solvent, adding an alkaline reagent for initiation, and then heating and stirring the mixture to obtain an s-triazine derivative; and mixing, by weight percentage, 10%-50% of the s-triazine derivative, 3%-16% of a C2-C4 alkynol, and 4%-10% of a C 12 -C 18 Alkyl acid, 0%-15% of a surfactant, 20%-40% of an organic solvent, and 0%-40% of water are mixed, totaling 100%, to obtain a triazine-based high-temperature CO2 corrosion inhibitor.

[0026] In an embodiment of the present invention, trichlorotriazine and diallylamine are reacted in a solvent to obtain an s-triazine derivative. Subsequently, 10%-50% of the s-triazine derivative is reacted with 3%-16% of a C2-C4 alkynol, 4%-10% of a C 12 -C 18By mixing alkanoic acid, 0%-15% surfactant, 20%-40% organic solvent, and 0%-40% water, a triazine-based high-temperature CO2 corrosion inhibitor can be prepared. The preparation method is relatively simple and has a high yield.

[0027] According to an embodiment of the present invention, the molar ratio of trichlorotriazine to diallylamine and alkaline reagent is 1:4-8:3-6, and within this ratio range, a triazine-based high-temperature CO2 corrosion inhibitor with a high yield can be obtained. The alkaline reagent is potassium hydroxide (KOH); and the solvent is dioxane.

[0028] Specifically, the method for preparing s-triazine derivatives includes: adding trichlorotriazine into a reactor, adding dioxane as a solvent, and stirring at room temperature (25°C) until dissolved. Then add diallylamine, stir at room temperature for 0.5-2h, and then add KOH and stir at 40°C for 1-3h. Then heat to 84°C and stir for 6-12h. After the reaction is completed, cool to room temperature, filter to remove inorganic salts (such as KCl, unreacted KOH), and add a large amount of dichloromethane to the filtrate to precipitate solids, filter and dry to obtain s-triazine derivatives. The specific reaction route for synthesizing s-triazine derivatives is as follows.

[0029] .

[0030] The following is a detailed description of a triazine-based high-temperature CO2 corrosion inhibitor and a preparation method thereof of the present invention in conjunction with specific embodiments and drawings. Unless otherwise specified, the drugs and reagents used can be purchased.

[0031] Example

[0032] Example 1

[0033] Preparation of s-triazine derivatives: Take 10mmol trichlorotriazine, dissolve it in 50mL dioxane, and stir at room temperature (25℃) until dissolved. Then add 40mmol diallylamine and stir at room temperature for 1h. Then add 40mmol KOH and stir at 40℃ for 2h. Then heat to 84℃ and stir for 12h. After the reaction is completed, cool to room temperature, filter to remove inorganic salts (such as KCl, unreacted KOH), add the filtrate to a large amount of dichloromethane solvent to precipitate solids, filter and dry to obtain s-triazine derivatives.

[0034] By nuclear magnetic resonance spectroscopy ( 1 H) and C NMR spectroscopy ( 13 The chemical shift of C) indicates that the s-triazine derivatives were successfully synthesized. 1H) chemical shifts are: δ 5.84 -5.71 (m, 1H), 5.21 -5.09 (m,2H), 3.99 (dt, J = 7.5, 1.1 Hz, 2H); C NMR ( 13 C) The chemical shifts are: δ166.33, 134.03, 116.53, 47.89.

[0035] Preparation of triazine-based high-temperature CO2 corrosion inhibitor A: dissolve 2g of dodecanoic acid and 10g of the s-triazine derivative synthesized in Example 1 in 10g of methanol; add 1g of 3-butyn-1-ol and 3g of sodium dodecylbenzenesulfonate to 5g of water; then add the methanol solution containing dodecanoic acid and the s-triazine derivative to the above-mentioned aqueous solution containing 3-butyn-1-ol and sodium dodecylbenzenesulfonate, mix well to obtain triazine-based high-temperature CO2 corrosion inhibitor A.

[0036] Example 2

[0037] Preparation of triazine-based high-temperature CO2 corrosion inhibitor B: dissolve 2g of hexadecanoic acid and 20g of the s-triazine derivative synthesized in Example 1 in 10g of dimethyl sulfoxide; add 2g of acetylene alcohol and 4g of sodium dodecylbenzene sulfonate to 5g of water; then add the dimethyl sulfoxide solution containing hexadecanoic acid and the s-triazine derivative to the above-mentioned aqueous solution containing acetylene alcohol and sodium dodecylbenzene sulfonate, mix well to obtain triazine-based high-temperature CO2 corrosion inhibitor B.

[0038] Example 3

[0039] Preparation of triazine-based high-temperature CO2 corrosion inhibitor C: dissolve 2g of hexadecanoic acid and 18g of the s-triazine derivative synthesized in Example 1 in 10g of dimethyl sulfoxide; add 2g of acetylene alcohol and 4g of sodium dodecylbenzene sulfonate to 5g of water; then add the dimethyl sulfoxide solution containing hexadecanoic acid and the s-triazine derivative to the above-mentioned aqueous solution containing acetylene alcohol and sodium dodecylbenzene sulfonate, mix well to obtain triazine-based high-temperature CO2 corrosion inhibitor C.

[0040] Example 4

[0041] Preparation of triazine-based high-temperature CO2 corrosion inhibitor D: dissolve 3g of dodecanoic acid and 20g of the s-triazine derivative synthesized in Example 1 in 10g of dimethyl sulfoxide; add 2g of acetylene alcohol and 4g of sodium dodecylbenzene sulfonate to 5g of water; then add the dimethyl sulfoxide solution containing dodecanoic acid and the s-triazine derivative to the above-mentioned aqueous solution containing acetylene alcohol and sodium dodecylbenzene sulfonate, mix well to obtain triazine-based high-temperature CO2 corrosion inhibitor D.

[0042] Example 5

[0043] Preparation of triazine-based high-temperature CO2 corrosion inhibitor E: dissolve 3 g of hexadecanoic acid and 15 g of the s-triazine derivative synthesized in Example 1 in 10 g of dimethyl sulfoxide; then add 5 g of 1,4-butynediol to the above dimethyl sulfoxide solution containing hexadecanoic acid and s-triazine derivatives; mix well to obtain triazine-based high-temperature CO2 corrosion inhibitor E.

[0044] Example 6

[0045] Preparation of triazine-based high-temperature CO2 corrosion inhibitor F: dissolve 5g of hexadecanoic acid and 10g of the s-triazine derivative synthesized in Example 1 in 20g of ethanol; add 5g of acetylene alcohol and 5g of sodium dodecyl sulfate to 10g of water; then add the ethanol solution containing hexadecanoic acid and the s-triazine derivative to the above-mentioned aqueous solution containing acetylene alcohol and sodium dodecyl sulfate, mix well to obtain the preparation of triazine-based high-temperature CO2 corrosion inhibitor F.

[0046] Example 7

[0047] Preparation of triazine-based high-temperature CO2 corrosion inhibitor G: dissolve 2g of pentadecanoic acid and 5g of the s-triazine derivative synthesized in Example 1 in 10g of N,N-dimethylformamide; add 2g of acetylene alcohol and 5g of sodium dodecylbenzene sulfonate to 15g of water; then add the N,N-dimethylformamide solution containing pentadecanoic acid and the s-triazine derivative to the above-mentioned aqueous solution containing acetylene alcohol and sodium dodecylbenzene sulfonate, mix well to obtain triazine-based high-temperature CO2 corrosion inhibitor G.

[0048] The triazine-based high-temperature CO2 corrosion inhibitors prepared in Examples 1 to 7 were tested for their corrosion effects on steel sheets in a high-temperature (60°C-120°C) and CO2-rich environment, wherein the mineralization of the water sample used was specifically: when the total mineralization was 28431.5 mg / L, K + and Na + 9375.4mg / L, Ca 2+ 1779.3mg / L, Mg 2+ 387.8mg / L, Cl - 16318.1mg / L, SO4 2- 78.5mg / L, HCO3 - The test fluid flow rate is 1m / s, the corrosion cycle is 2 days, and the CO2 pressure is 2MPa. According to the petroleum and natural gas industry standard SY / T5273-2000 of the People's Republic of China, the weight loss analysis of the steel sheet before and after corrosion was carried out and the corrosion inhibition rate was calculated.

[0049] When the dosage of each triazine-based high-temperature CO2 corrosion inhibitor is 300 mg / L, the corrosion rate at different temperatures (60°C-120°C) is analyzed and the corrosion inhibition rate is calculated. The specific results are shown in Table 1.

[0050] Table 1. Corrosion inhibition performance of triazine-based high temperature CO2 corrosion inhibitor at different temperatures

[0051]

[0052] As can be seen from Table 1 above, the corrosion inhibition rate of the triazine-based high-temperature CO2 corrosion inhibitor prepared by the present invention is as high as 93.19% at 120°C, indicating that the corrosion inhibitor prepared in Example 2 has good performance at high temperature (120°C). For the triazine-based high-temperature CO2 corrosion inhibitors prepared in other Examples 1, 3-4, the corrosion inhibition rate is also maintained at more than 92% in a 60-120°C environment, and for the triazine-based high-temperature CO2 corrosion inhibitors prepared in other Examples 5-7, the corrosion inhibition rate is also maintained at more than 70% in a 60-120°C environment.

[0053] Furthermore, the surface morphology of the untested steel sheet (blank test, such as steel sheet 1723 and steel sheet 1061), the steel sheet 1723 without the use of the triazine-based high temperature CO2 corrosion inhibitor (hereinafter referred to as the corrosion inhibitor), and the steel sheet 1061 using the triazine-based high temperature CO2 corrosion inhibitor (hereinafter referred to as the corrosion inhibitor) in Example 2 were selected for analysis. The specific test results are as follows: Figure 1A-1B shown.

[0054] Figure 1A The actual pictures of the untested steel sheet 1723 and the steel sheet 1723 without the corrosion inhibitor are shown in FIG. Figure 1B These are actual pictures of the untested steel sheet 1061 and the steel sheet 1061 using the corrosion inhibitor in Example 2.

[0055] like Figure 1A and Figure 1B As shown, the steel sheet 1723 without the corrosion inhibitor has completely lost its metallic luster after the test, and the surface is covered with a layer of corrosion products. However, the steel sheet 1061 using the corrosion inhibitor in Example 2 still has a metallic luster after the test, and there is no obvious corrosion mark on the surface. This shows that the corrosion inhibitor provided by the present invention has the effect of shielding CO2 corrosion.

[0056] Furthermore, the microscopic morphologies of the untested steel sheet 1723, the steel sheet 1723 without the corrosion inhibitor, and the steel sheet 1061 with the corrosion inhibitor in Example 2 were analyzed. The specific analysis results are as follows: Figure 2 shown.

[0057] Figure 2 are scanning electron microscope (SEM) images of different steel sheets, wherein a is the SEM image of the untested steel sheet 1723, b is the SEM image of the steel sheet 1723 without using the corrosion inhibitor, and c is the SEM image of the steel sheet 1061 using the corrosion inhibitor in Example 2.

[0058] like Figure 2As shown, clear grinding scratches can be seen on the surface of the untested steel sheet 1723. A large amount of corrosion products are accumulated on the surface of the steel sheet 1723 without the corrosion inhibitor, and a crystal-like substance is produced. This crystal-like product may be FeCO3, indicating that the surface corrosion of the steel sheet 1723 without the corrosion inhibitor is very serious. Although scratches can be seen on the surface of the steel sheet using the corrosion inhibitor in Example 2, there is no accumulation of similar crystal substances, indicating that under the protection of the corrosion inhibitor, the surface corrosion of the steel sheet 1061 is weak, and the corrosion inhibitor has a good anti-corrosion effect.

[0059] In summary, the present invention provides a triazine-based high-temperature CO2 corrosion inhibitor and a preparation method thereof, which increases the binding energy between the corrosion inhibitor molecule and the Fe atom on the carbon steel metal surface by utilizing the multiple N sites and double bonds contained in the triazine-based high-temperature CO2 corrosion inhibitor, so that the corrosion inhibitor is firmly adsorbed on the metal surface. The triazine-based high-temperature CO2 corrosion inhibitor can form a dense covering film on the carbon steel surface to prevent the metal from being corroded. 12 -C 18 After compounding with alkanoic acid, organic solvents and other compounds, a corrosion inhibition rate of more than 90% can be obtained under working conditions above 80°C, with a mineralization higher than 25000 mg / L and rich in CO2. It has a good anti-corrosion effect on carbon steel and can be used in oil and gas field production with small dosage, good effect and no pollution to the environment.

[0060] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A triazine-based high temperature CO2 corrosion inhibitor, characterized in that: In terms of weight percentage, the triazine-based high temperature CO2 corrosion inhibitor comprises: 10%-50% of s-triazine derivatives, 3%-16% of C2-C4 alkynols, 4%-10% of C 12 -C 18 Alkane acid, 0%-15% surfactant, 20%-40% organic solvent, and 0%-40% water, totaling 100%; The triazine-based high-temperature CO2 corrosion inhibitor is suitable for resisting CO2 corrosion at high temperatures of 60°C-120°C, and the s-triazine derivative has a structure as shown in formula (1): Formula (1); The s-triazine derivative is obtained by reacting trichlorotriazine and diallylamine under the initiation of an alkaline reagent.

2. The triazine-based high-temperature CO2 corrosion inhibitor according to claim 1, characterized in that: The C2-C4 alkynol is selected from a C2-C4 monohydric alkynol or a C4 dihydric alkynol.

3. The triazine-based high temperature CO2 corrosion inhibitor according to claim 1, characterized in that: The surfactant is selected from any one of sodium dodecylbenzene sulfonate and sodium dodecyl sulfate.

4. The triazine-based high temperature CO2 corrosion inhibitor according to claim 1, characterized in that: The organic solvent is selected from any one of methanol, ethanol, dimethyl sulfoxide and N,N-dimethylformamide.

5. The triazine-based high temperature CO2 corrosion inhibitor according to claim 1, characterized in that: The triazine-based high temperature CO2 corrosion inhibitor comprises: 40%-50% of s-triazine derivatives, 3%-10% of C2-C4 acetylenic alcohols, 5%-12% of surfactants, 4%-8% of C 12 -C 18 Alkanoic acid, 20%-30% organic solvent and 10%-20% water, totaling 100%.

6. A method for preparing a triazine-based high-temperature CO2 corrosion inhibitor as claimed in any one of claims 1 to 5, characterized in that: The preparation method comprises: After trichlorotriazine and diallylamine are uniformly mixed in a solvent, an alkaline reagent is added for initiation, and after heating and stirring for reaction, an s-triazine derivative is separated; In terms of weight percentage, 10% to 50% of s-triazine derivatives, 3% to 16% of C2-C4 alkynols, 4% to 10% of C 12 -C 18 Alkyl acid, 0%-15% of a surfactant, 20%-40% of an organic solvent, and 0%-40% of water are mixed, totaling 100%, to obtain the triazine-based high-temperature CO2 corrosion inhibitor.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the trichlorotriazine to the diallylamine and the alkaline reagent is 1:4-8:3-6.

8. The preparation method according to claim 6, characterized in that: The alkaline reagent is KOH; The solvent is dioxane.

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