Carbon dioxide corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention discloses a carbon dioxide corrosion inhibitor and a preparation method and application thereof.The preparation method comprises the steps that lauryl amine is dissolved in ethyl alcohol, the pH value of a system is regulated and controlled, then tetrabutylammonium bromide is added, and the tetrabutylammonium bromide is stirred and dissolved evenly; and adding a sodium 2-chloroethanesulfonate solution into the obtained reaction solution, and stirring for reaction to obtain the carbon dioxide corrosion inhibitor. The carbon dioxide corrosion inhibitor is sodium 2-(dodecyl amino) ethyl sulfonate and contains a sulfonic acid group, and the sulfonic acid group has good high temperature resistance and CO2 partial pressure resistance and can effectively inhibit corrosion of pipelines and equipment in the oil and gas exploitation process.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield chemistry, and relates to a carbon dioxide corrosion inhibitor, a preparation method thereof, and an application thereof. Background Art

[0002] With the increasing demand for oil, China has strengthened the exploitation of low-permeability oil and gas resources. By using carbon dioxide flooding, the recovery rate of low-permeability oil and gas fields can be greatly improved. The high-temperature and high-pressure carbon dioxide in the carbon dioxide flooding process will cause serious electrochemical corrosion to the pipelines and equipment of oil and gas fields. Adding a corrosion inhibitor is one of the most economical and effective ways to solve carbon dioxide corrosion. Among them, pyridinium quaternary salts were once used to inhibit carbon dioxide corrosion due to their good temperature resistance, but due to their high toxicity and poor performance in resisting high-pressure carbon dioxide corrosion, they have been gradually phased out. Amide-based carbon dioxide corrosion inhibitors have poor performance in resisting high temperature and high-pressure carbon dioxide, and generally can only be used in conventional gathering and transportation environments. Imidazoline-based corrosion inhibitors are currently the most commonly used carbon dioxide corrosion inhibitors due to their biodegradability and excellent carbon dioxide corrosion resistance. After being compounded with thiourea, their corrosion inhibition performance can be further improved. However, due to the extremely high price of polyethylenepolyamine at present, the cost of imidazoline corrosion inhibitors is very high, and imidazoline corrosion inhibitors are prone to hydrolysis in corrosive media, resulting in performance degradation. At the same time, conventional carbon dioxide corrosion inhibitors, such as imidazoline, amide, thiourea, etc., cannot effectively inhibit the corrosion of high-temperature and high-pressure carbon dioxide in the carbon dioxide flooding process, and new corrosion inhibitors need to be developed. Summary of the Invention

[0003] Aiming at the problems existing in the prior art, the present invention provides a carbon dioxide corrosion inhibitor, a preparation method thereof, and an application thereof, so as to solve the technical problems that amide-based carbon dioxide corrosion inhibitors in the prior art have poor performance in resisting high temperature and high-pressure carbon dioxide, the processing cost of imidazoline-based corrosion inhibitors is high, and imidazoline corrosion inhibitors are prone to hydrolysis in corrosive media and cannot effectively inhibit the corrosion of high-temperature and high-pressure carbon dioxide in the carbon dioxide flooding process.

[0004] The present invention is realized through the following technical solutions:

[0005] A preparation method of a carbon dioxide corrosion inhibitor, comprising the following steps:

[0006] S1: Dissolve dodecylamine in ethanol, adjust the pH value of the system, and then add tetrabutylammonium bromide, and stir to dissolve evenly;

[0007] S2: Add a 2-chloroethylsulfonate solution to the reaction solution obtained in step S1, and stir to react to obtain the carbon dioxide corrosion inhibitor.

[0008] Preferably, the molar ratio of dodecylamine to 2-chloroethylsulfonate is 1:(1-1.2).

[0009] Preferably, in the step S1, the pH value of the regulation system is 8-9.

[0010] Preferably, in the step S2, the 2-chloroethylsulfonate solution is added in a dropping manner.

[0011] Preferably, in the step S2, the addition rate of the 2-chloroethylsulfonate solution is 7*10 -3 mol / min.

[0012] Preferably, in the step S2, after the addition of the 2-chloroethylsulfonate solution is completed, the temperature of the reaction system is controlled at 80-90 °C, and the reaction time is 6-12 h.

[0013] Preferably, after the step S2, it further includes removing ethanol by rotary evaporation and purifying by recrystallization with methanol to obtain the carbon dioxide corrosion inhibitor.

[0014] A carbon dioxide corrosion inhibitor is prepared by the above method.

[0015] Application of the above carbon dioxide corrosion inhibitor in the carbon dioxide flooding process, adding the carbon dioxide corrosion inhibitor to the water medium at the oilfield site for carbon dioxide flooding process operation; the operation temperature is 25 °C - 120 °C, and the operation pressure is 0.1 - 6 MPa.

[0016] Preferably, the dosage of the carbon dioxide corrosion inhibitor is 10 - 50 mg·L -1 .

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] The present invention discloses a preparation method of a carbon dioxide corrosion inhibitor, dissolving dodecylamine in ethanol, regulating the pH value of the system, then adding tetrabutylammonium bromide, stirring and dissolving evenly; adding a 2-chloroethylsulfonate solution to the obtained reaction solution, stirring and reacting to obtain the carbon dioxide corrosion inhibitor, and the carbon dioxide corrosion inhibitor is 2-(dodecylamino)ethyl sulfonate. Due to the presence of amino and sulfonic acid groups with multiple adsorption centers, the corrosion inhibitor has good high-temperature and CO2 corrosion resistance.

[0019] Furthermore, the molar ratio of dodecylamine to 2-chloroethylsulfonate is 1:(1 - 1.2), which can effectively ensure a higher conversion rate of dodecylamine.

[0020] Furthermore, in the step S1, the pH value of the regulation system is 8 - 9, making the reaction system weakly alkaline. Under this reaction system, the chlorination reaction is more likely to occur.

[0021] Further, in the step S2, the 2-chloroethylsulfonate solution is added dropwise to avoid too violent reaction and effectively control the reaction rate.

[0022] Further, in the step S2, the addition rate of the 2-chloroethylsulfonate solution is 7×10 -3 mol / min, effectively avoiding too violent reaction and side reactions.

[0023] Further, in the step S2, after the addition of the 2-chloroethylsulfonate solution is completed, the temperature of the reaction system is controlled at 80-90°C and the reaction time is 6-12 h, so that the chlorination reaction can be fully completed.

[0024] Further, after the step S2, it also includes removing ethanol by rotary evaporation and purifying by recrystallization with methanol to obtain the carbon dioxide corrosion inhibitor, effectively ensuring the purity of the product.

[0025] Meanwhile, the present invention also discloses a carbon dioxide corrosion inhibitor obtained by the above method.

[0026] Meanwhile, the application of the above carbon dioxide corrosion inhibitor in the carbon dioxide flooding process is also disclosed. When in use, the carbon dioxide corrosion inhibitor is directly added to the water medium at the oilfield site for carbon dioxide flooding process operation, which is convenient to operate. The operating temperature is 25°C to 120°C and the operating pressure is 0.1 to 6 MPa, having the advantage of being highly resistant to high temperature and high carbon dioxide pressure.

[0027] Meanwhile, further, the dosage of the carbon dioxide corrosion inhibitor is 10-50 mg·L -1 , and good corrosion inhibition effect can be achieved with less dosage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 is a schematic flow chart of a method for preparing a carbon dioxide corrosion inhibitor in the present invention;

[0030] Figure 2 is the H-NMR spectrum of the product obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meanings understood by those skilled in the art with respect to the present invention. In case of conflicts, the definitions in this specification shall prevail.

[0032] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being restricted by any specific theory or mechanism.

[0033] In this document, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the ranges (including integers and fractions).

[0034] In this document, unless otherwise specified, the terms "comprising", "including", "containing", "having", or similar expressions cover the meanings of "consisting of" and "consisting essentially of". For example, "A comprises a" covers the meanings of "A comprises a and others" and "A consists only of a".

[0035] In this document, for the sake of brevity of description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as being within the scope described in this specification.

[0036] As Figure 1 shown, the present invention provides a method for preparing a carbon dioxide corrosion inhibitor, comprising the following steps:

[0037] S1: Dissolve dodecylamine in ethanol, adjust the pH value of the system to 8 - 9, then add tetrabutylammonium bromide, control the temperature of the reaction system at 50 °C, and stir to dissolve evenly;

[0038] S2: Add a 2-chloroethylsulfonate solution to the reaction solution obtained in step S1 by dropwise addition, and stir to react. Specifically, the addition rate of the 2-chloroethylsulfonate solution is 7*10 -3 mol / min, then control the temperature of the reaction system at 80 - 90 °C, the reaction time at 6 - 12 h, remove ethanol by rotary evaporation, and purify by recrystallization with methanol to obtain the carbon dioxide corrosion inhibitor. Among them, the molar ratio of dodecylamine to 2-chloroethylsulfonate is 1:(1 - 1.2);

[0039] The present invention synthesizes compounds containing sulfonic acid groups, which are used to inhibit the corrosion of carbon steel in an environment with high temperature and high CO2 partial pressure, and their preparation methods. In this process, a chlorination reaction is carried out between dodecylamine and sodium 2-chloroethylsulfonate, and the chlorination reaction conditions are optimized. The application of the obtained reaction product and its application method are also studied, including the ratio of dodecylamine compounds and other raw materials in the synthesis process of the corrosion inhibitor, the synthesis temperature conditions, and the selection of dispersants for the corrosion inhibitor. Based on the high-temperature and high-pressure CO2 resistance characteristics of the sulfonic acid group, the prepared corrosion inhibitor can effectively inhibit the corrosion of carbon steel under high temperature and high CO2 partial pressure conditions. Moreover, this corrosion inhibitor has a small dosage during actual use, a significant corrosion inhibition effect, and excellent high-temperature and CO2 corrosion resistance properties.

[0040] To achieve the above object, according to one aspect of the present invention, a compound containing a sulfonic acid group is provided, which is characterized by having the structural formula of formula (I) as follows:

[0041]

[0042] The preparation steps of sodium 2-(dodecylamino)ethylsulfonate are as follows: Using dodecylamine and sodium 2-chloroethylsulfonate with a molar mass ratio of 1:(1 - 1.2) as raw materials, a chlorination reaction is carried out in an alkaline environment in the presence of a catalyst to generate the sodium 2-(dodecylamino)ethylsulfonate compound. The preferred molar ratio of dodecylamine to sodium 2-chloroethylsulfonate in the synthesis step is 1:1. The crude product obtained from the chlorination reaction needs to be rotary evaporated to remove the excess organic solvent and purified by recrystallization with methanol. The N-H in this corrosion inhibitor has good adsorption properties, which can enable the corrosion inhibitor to adsorb on carbon steel. The long-chain alkane structure has good hydrophobic characteristics, enabling the corrosion inhibitor to form a stable hydrophobic film on the surface of carbon steel. The contained sulfonic acid group has good high-temperature resistance performance, effectively improving the high-temperature resistance performance of the corrosion inhibitor, so that the material has good corrosion inhibition effect under high temperature and high CO2 partial pressure conditions. This high-temperature and high CO2 partial pressure resistant corrosion inhibitor can be used in a process environment with a temperature ranging from room temperature (such as 25°C) to 120°C and a saturated CO2 pressure up to 6 MPa. The corrosion inhibitor of the present invention can be directly added to the corrosive medium.

[0043] The following further elaborates the present invention in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0044] Conventional instrument and equipment in the art are used in the following examples. For the experimental methods without specific conditions noted in the following examples, they are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Various raw materials are used in the following examples. Unless otherwise stated, commercially available products with conventional specifications in the art are used. In the specification of the present invention and the following examples, unless otherwise specified, "%" represents weight percentage, "parts" represents weight parts, and the ratio represents weight ratio.

[0045] Example 1

[0046] Dissolve 0.1 mol of dodecylamine in 110 mL of ethanol, adjust the pH value of the solution to 8.0 with 6 mol / L sodium hydroxide solution, and then add a catalytic amount of tetrabutylammonium bromide. Pour the reaction solution into a 250 mL three-necked flask equipped with a magnetic stirrer, reflux condenser, constant pressure dropping funnel and thermometer, heat up to 50 °C and keep warm. Dropwise add 35 mL of an aqueous solution of 3 mol / L 2-chloroethylsulfonate sodium to the heated reaction solution, and finish dropping in about 15 min. Heat the system to 85 °C and react for 6 h. After cooling, remove the solvent in the system by rotary evaporation, recrystallize with methanol and filter to obtain a filter cake, and dry it under vacuum to obtain the product. Take an appropriate amount of the purified product and dissolve it in deuterated chloroform solvent, and then carry out H-NMR test. The test results are as Figure 2 shown. In the figure, 1H NMR (500 MHz) δ 3.33 (tt, J = 5.8, 4.6 hz, 1H), 3.03 - 2.98 (m, 2H), 2.97 - 2.91 (m, 2H), 2.66 (td, J = 5.5, 4.6 hz, 2H), 1.52 - 1.43 (m, 2H), 1.37 - 1.22 (m, 17H), 0.94 - 0.84 (m, 3H). It can be Figure 2 seen that the above NMR test results indicate the successful synthesis of the target product sodium 2-(dodecylamino)ethylsulfonate.

[0047] Example 2

[0048] Dissolve 0.1 mol of dodecylamine in 110 mL of ethanol, adjust the pH value of the solution to 8.5 with 6 mol / L sodium hydroxide solution, and then add a catalytic amount of tetrabutylammonium bromide. Pour the reaction solution into a 250 mL three-necked flask equipped with a magnetic stirrer, reflux condenser, constant pressure dropping funnel and thermometer, heat up to 50 °C and keep warm. Dropwise add 38 mL of an aqueous solution of 3 mol / L 2-chloroethylsulfonate sodium to the heated reaction solution, and finish dropping in about 15 min. Heat the system to 90 °C and react for 9 h. After cooling, remove the solvent in the system by rotary evaporation, recrystallize with methanol and filter to obtain a filter cake, and dry it under vacuum to obtain the product.

[0049] According to the industry standard SY / T 5273-2000, the corrosion inhibition performance was evaluated. The evaluation results are shown in Table 1.

[0050] Table 1 Comparative evaluation results of the corrosion inhibitor in this example under different addition amounts

[0051]

[0052] It can be seen from the test data in Table 1 that under high temperature and high CO2 partial pressure conditions, the corrosion inhibitor of the present invention has a significant protective effect on titanium alloy, and with the increase of the addition amount, the protective effect becomes more and more significant.

[0053] Example 3

[0054] Dissolve 0.1 mol of dodecylamine in 110 mL of ethanol, adjust the pH of the solution to 9 with 6 mol / L sodium hydroxide solution, and then add a catalytic amount of tetrabutylammonium bromide. Pour the reaction solution into a 250 mL three-necked flask equipped with a magnetic stirrer, reflux condenser, constant pressure dropping funnel and thermometer, heat up to 50 °C and keep warm. Add 40 mL of an aqueous solution of 3 mol / L 2-chloroethylsulfonate dropwise to the heated reaction solution, and finish dropping in about 15 min. Heat the system to 85 °C and react for 12 h. After cooling, remove the solvent in the system by rotary evaporation, recrystallize with methanol and filter to obtain the filter cake, and dry it under vacuum to obtain the product.

[0055] According to the industry standard SY / T 5273-2000, the corrosion inhibition performance was evaluated, and the evaluation results are shown in Table 2.

[0056] Table 2 Comparative evaluation results of the corrosion inhibitor in this example under different addition amounts

[0057]

[0058] It can be seen from the test data in Table 2 that under high temperature and high CO2 partial pressure conditions, the corrosion inhibitor of the present invention has a significant protective effect on titanium, and with the increase of the addition amount, the protective effect becomes more and more significant.

[0059] Example 4

[0060] A preparation method of a carbon dioxide corrosion inhibitor, comprising the following steps:

[0061] S1: Dissolve dodecylamine in ethanol, adjust the pH value of the system to 8, then add tetrabutylammonium bromide, control the temperature of the reaction system to 50 °C, and stir to dissolve evenly; wherein, the molar ratio of dodecylamine to 2-chloroethylsulfonate is 1:1;

[0062] S2: Add sodium 2-chloroethyl sulfonate solution dropwise to the reaction solution obtained in step S1, stir and react. Specifically, the addition rate of the sodium 2-chloroethyl sulfonate solution is 7*10 -3 mol / min, then control the temperature of the reaction system at 80 °C, react for 6 h, remove ethanol by rotary evaporation, and purify by recrystallization from methanol to obtain the carbon dioxide corrosion inhibitor.

[0063] Example 5

[0064] A preparation method of a carbon dioxide corrosion inhibitor, comprising the following steps:

[0065] S1: Dissolve dodecylamine in ethanol, adjust the pH value of the system to 9, then add tetrabutylammonium bromide, control the temperature of the reaction system at 50 °C, and stir until dissolved evenly; wherein, the molar ratio of dodecylamine to sodium 2-chloroethyl sulfonate is 1:1.2;

[0066] S2: Add sodium 2-chloroethyl sulfonate solution dropwise to the reaction solution obtained in step S1, stir and react, then control the temperature of the reaction system at 85 °C, react for 10, remove ethanol by rotary evaporation, and purify by recrystallization from methanol to obtain the carbon dioxide corrosion inhibitor.

[0067] Example 6

[0068] A preparation method of a carbon dioxide corrosion inhibitor, comprising the following steps:

[0069] S1: Dissolve dodecylamine in ethanol, adjust the pH value of the system to 9, then add tetrabutylammonium bromide, control the temperature of the reaction system at 50 °C, and stir until dissolved evenly; wherein, the molar ratio of dodecylamine to sodium 2-chloroethyl sulfonate is 1:1.2;

[0070] S2: Add sodium 2-chloroethyl sulfonate solution dropwise to the reaction solution obtained in step S1, stir and react, then control the temperature of the reaction system at 90 °C, react for 12 h, remove ethanol by rotary evaporation, and purify by recrystallization from methanol to obtain the carbon dioxide corrosion inhibitor.

[0071] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A preparation method of a carbon dioxide corrosion inhibitor, characterized in that, It includes the following steps: S1: Dissolve dodecylamine in ethanol, adjust the pH value of the system, and then add tetrabutylammonium bromide and stir until dissolved evenly; S2: Add sodium 2-chloroethylsulfonate solution to the reaction solution obtained in step S1, stir and react to obtain the carbon dioxide corrosion inhibitor.

2. The preparation method of a carbon dioxide corrosion inhibitor according to claim 1, characterized in that, The molar ratio of the dodecylamine to the sodium 2-chloroethylsulfonate is 1:(1-1.2).

3. The preparation method of a carbon dioxide corrosion inhibitor according to claim 1, characterized in that, In step S1, the pH value of the system is adjusted to 8-9.

4. The preparation method of a carbon dioxide corrosion inhibitor according to claim 1, characterized in that, In step S2, the sodium 2-chloroethylsulfonate solution is added in a dropwise manner.

5. The preparation method of a carbon dioxide corrosion inhibitor according to claim 1, characterized in that, In the step S2, the addition rate of the 2-chloroethylsulfonate solution is 7×10 -3 mol / min.

6. The preparation method of a carbon dioxide corrosion inhibitor according to claim 1, characterized in that, In step S2, after the addition of the sodium 2-chloroethylsulfonate solution is completed, the temperature of the reaction system is controlled at 80-90 °C, and the reaction time is 6-12 h.

7. The preparation method of a carbon dioxide corrosion inhibitor according to claim 1, characterized in that, After step S2, it further includes removing ethanol by rotary evaporation and purifying by recrystallization with methanol to obtain the carbon dioxide corrosion inhibitor.

8. A carbon dioxide corrosion inhibitor, characterized in that, It is obtained by the method described in any one of claims 1-8.

9. Use of a carbon dioxide corrosion inhibitor as described in claim 8 in the process of carbon dioxide flooding, characterized in that, Add the carbon dioxide corrosion inhibitor to the water medium at the oilfield site for carbon dioxide flooding process operations; the operation temperature is 25 °C to 120 °C, and the operation pressure is 0.1 to 6 MPa.

10. Application of a carbon dioxide corrosion inhibitor described in claim 8 in the carbon dioxide flooding process, characterized in that, The dosage of the carbon dioxide corrosion inhibitor is 10 - 50 mg·L -1 .

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