High-temperature corrosion inhibitor for acidification and preparation method thereof

Abstract

The application discloses a high-temperature corrosion inhibitor for acidification and a preparation method thereof, and mainly relates to the technical field of inhibiting the corrosion of metal materials in an acidic liquid. The high-temperature corrosion inhibitor for acidification comprises aniline, N-acetylimidazole, phenylethanone, butyne diol, sodium lignosulfonate, lauric acid diethanolamide and anhydrous ethanol. Compared with the prior art, the high-temperature corrosion inhibitor for acidification is prepared by the reaction of aniline, N-acetylimidazole and phenylethanone, further, the butyne diol, the sodium lignosulfonate and the lauric acid diethanolamide are added to the corrosion inhibitor main body to form a synergistic effect, the sodium lignosulfonate can better improve the overall slow-release property of the corrosion inhibitor and the stability of the corrosion inhibitor in a high-temperature acid liquid, and the metal can be more effectively protected.

Description

Technical Field

[0001] This invention relates to the field of corrosion inhibition technology for metallic materials in acidic liquids, and particularly to a high-temperature corrosion inhibitor for acidification and its preparation method. Background Technology

[0002] High-temperature corrosion inhibitors are chemical additives used to slow down the corrosion rate of metallic materials in high-temperature environments. They are primarily used in acidic solvents to form a protective film, mainly protecting metallic materials from corrosion by acidic media. At high temperatures, metallic materials are easily corroded and damaged by acidic media, and high-temperature corrosion inhibitors used in acidizing processes can reduce the corrosion rate and extend the service life of metallic materials. Currently, products developed for oilfield construction environments have made significant progress in corrosion protection of pipelines, equipment, and surface facilities in acidizing processes for oil and gas wells and water injection wells at temperatures not exceeding 160℃. However, during oilfield development, oil and gas pipelines and equipment face high-temperature, high-pressure, and highly corrosive environments. The higher the temperature resistance of the high-temperature corrosion inhibitor, the longer its application range and lifespan. If the temperature resistance of the high-temperature corrosion inhibitor is insufficient, it is prone to decomposition, deterioration, or failure at high temperatures, failing to provide effective corrosion inhibition. Therefore, the temperature resistance of high-temperature corrosion inhibitors is crucial in oilfield development processes.

[0003] To improve the high-temperature resistance of high-temperature corrosion inhibitors used in acidification, raw materials with high heat resistance and thermal stability can be selected during the preparation of the inhibitor, thereby improving its high-temperature performance. Examples include aromatic compounds and heterocyclic compounds. Furthermore, adjusting the inhibitor's formulation and preparation process can alter its molecular structure and physical properties, thus improving its stability at high temperatures. For instance, introducing high-molecular-weight polymers or using crosslinking agents can enhance the adhesion between the inhibitor and the metal surface through pretreatment such as sandblasting and rust removal, thereby improving its high-temperature resistance. Combining different types of corrosion inhibitors can leverage the synergistic effect of each component to improve the overall high-temperature resistance. For example, organic and inorganic corrosion inhibitors can be combined to utilize their synergistic effect and improve the inhibitor's heat resistance. Mannich bases are widely used as hydrochloric acid acid corrosion inhibitors. The N and O atoms in Mannich bases can provide lone pairs of electrons, which can combine with the empty P orbitals on the Fe atoms of metal to form stable chemical bonds. In practical applications, Mannich bases can form an adsorption film on the metal surface, preventing the corrosive medium from penetrating inward and thus protecting the metal.

[0004] CN114437694A discloses an acid corrosion inhibitor and its preparation and application, comprising: 5-10 parts of isothiazolinone derivatives and 30-40 parts of Mannich base compounds. This invention also discloses the preparation method and application of the acid corrosion inhibitor. In this invention, the high-temperature acidizing corrosion inhibitor utilizes nitrogen- and sulfur-containing electron-rich heterocyclic compounds and polyoxymethylene dimethyl ether compounds as core additives, combined with antimony oxide, copper iodide corrosion inhibitors, and iron ion stabilizers, to meet the requirements of ultra-high temperature deep well acidizing stimulation operations at 200℃ and above.

[0005] CN111499527A discloses a method for preparing and applying a cross-linked acid system high-temperature resistant acidizing corrosion inhibitor. The preparation method includes: adding aldehyde monomers, ketone monomers, and amine monomers to a reactor, dispersing them with anhydrous ethanol, and reacting at 60–100°C to obtain a Mannich base; after cooling the system, adding a haloalkane, and continuing the reaction at 60–100°C to obtain a Mannich base quaternary ammonium salt corrosion inhibitor. The obtained Mannich base quaternary ammonium salt corrosion inhibitor can be used directly without purification. This invention's acidizing corrosion inhibitor has better temperature resistance and compatibility, can be used at high temperatures up to 180°C, and is suitable for various processes in oilfield acidizing operations.

[0006] The solutions reported in the above patent documents are all for improving the high-temperature corrosion inhibitors, but they cannot simultaneously solve the storage problem of high-temperature corrosion inhibitors. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to improve the corrosion inhibition rate and storage stability of high-temperature corrosion inhibitors for acidification.

[0008] To achieve the above objectives, the present invention provides a high-temperature corrosion inhibitor for acidification and a method for preparing the same.

[0009] The preparation method of the high-temperature corrosion inhibitor for acidification includes the following steps:

[0010] (1) Add N-acetylimidazole and aniline to anhydrous ethanol, stir at room temperature for 1-2 hours, then add acetophenone, add hydrochloric acid to adjust the pH to acidic, reflux and stir for 6-10 hours to obtain the corrosion inhibitor body;

[0011] (2) Add butynediol, sodium lignosulfonate and lauric acid diethanolamide to the corrosion inhibitor at room temperature and pressure, stir at 80-90℃ for 0.5-1 hour, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0012] In step (1), the pH value is adjusted to acidity, that is, the pH value is adjusted to 2-6.

[0013] The reflux temperature in step (1) is 80-90℃.

[0014] In step (1), the weight ratio of N-acetylimidazole, aniline, acetophenone, and anhydrous ethanol is 1.0-1.5:1.0-2.0:0.5-1.5:6-10; preferably 1.0-1.2:1.0-1.2:0.8-1.0:6-8.

[0015] In step (2), the weight ratio of the corrosion inhibitor, butynediol, sodium lignosulfonate, and diethanolamide of laurate is 8-15:0.2-1:0.1-0.5:0.1-0.5; preferably 9-11:0.5-1:0.2-0.4:0.2-0.4.

[0016] The corrosion inhibition performance of a corrosion inhibitor can be affected by differences in the molecular structure of the raw materials and the proportions of each component. Therefore, it is necessary to screen the raw material components and proportions. The high-temperature corrosion inhibitor for acidification of the present invention first undergoes nucleophilic addition of aniline to the carbonyl group of N-acetylimidazole, followed by dehydration to obtain an imine ion intermediate. As a nucleophile, acetophenone is further reacted under acidic conditions to generate an enol intermediate. The imine ion attacks the enol structure with an active hydrogen atom, loses a proton, and yields the Mannich base product, which is the main body of the corrosion inhibitor of the present invention. By adsorbing onto the metal surface, it forms a protective film, preventing further corrosion of the metal by the acidic medium and thus protecting the metal. Furthermore, this invention incorporates butynediol, sodium lignosulfonate, and lauric acid diethanolamide. Sodium lignosulfonate is a water-soluble anionic polymer containing a rigid benzene ring, a strongly hydrated sulfonate group, and various active groups. Its non-polar groups promote the formation of a protective hydrophobic layer on the metal surface after adsorption. It exhibits good chemical stability and temperature resistance, making it suitable for high-temperature acid environments. It also acts as a dispersant to improve the dispersion of the corrosion inhibitor in acid, prevent the formation of blocky precipitates on the metal surface, and enhance stability during storage. Lauric acid diethanolamide is a surfactant that forms a protective film on the metal surface, reducing the contact between the metal and the acid, thereby lowering the corrosion rate. It also helps to uniformly disperse the corrosion inhibitor components, improving overall stability. Butynediol contains active hydroxyl groups, which, upon contact with the metal surface, can undergo coordination or redox reactions with active metal ions or metal oxides on the metal surface, increasing the coverage of the metal surface, improving the density of the protective film, reducing corrosion reactions, and thus lowering the metal corrosion rate. Through synergistic effects with the main corrosion inhibitor, the overall slow-release properties and stability of the corrosion inhibitor in high-temperature acid solutions are better improved, thus protecting the metal more effectively.

[0017] The beneficial effects of this invention are:

[0018] Compared with the prior art, the high-temperature corrosion inhibitor for acidification of the present invention is obtained by reacting aniline, N-acetylimidazole and acetophenone to obtain the main body of the corrosion inhibitor. Furthermore, the present invention also incorporates butynediol, sodium lignosulfonate, and diethanolamide of laurate with the main body of the corrosion inhibitor for synergistic effect. Sodium lignosulfonate better improves the overall slow-release properties and stability of the corrosion inhibitor in high-temperature acid solutions, and more effectively protects the metal. Detailed Implementation

[0019] The parameters of the specific chemical substances used in the examples are from the following sources:

[0020] N80 steel pipe: inner and outer diameter specifications are 127mm×6mm, manufacturer is Cangzhou Qidong Trading Co., Ltd., steel grade is P110.

[0021] Imidazoline oleate: Manufacturer: Zhengzhou Huiju Chemical Co., Ltd., Product No.: A052471.

[0022] N-Acetylimidazole: Manufacturer: Jiangsu Runfeng Synthetic Technology Co., Ltd., Model No. 2466-76-4.

[0023] Butynediol: Manufacturer: Shanghai Hans Chemical Co., Ltd., Product No.: B802173-5g.

[0024] Sodium lignosulfonate: Manufacturer: Shandong Ailiwan Chemical Technology Co., Ltd., Model: ALW-A.

[0025] Lauric acid diethanolamide: Manufacturer is Hubei Shiteng Chemical Technology Co., Ltd., product number 021.

[0026] Example 1

[0027] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0028] Add 120g benzaldehyde and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH to 4.5, reflux at 85℃ and stir for 8 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0029] Example 2

[0030] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0031] Add 120g of cinnamaldehyde and 100g of aniline to 700g of anhydrous ethanol, stir at room temperature for 1 hour, then add 80g of acetophenone, add 10wt% hydrochloric acid to adjust the pH to 4.5, reflux at 85℃ and stir for 8 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0032] Example 3

[0033] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0034] Add 120g of oleic acid imidazoline and 100g of aniline to 700g of anhydrous ethanol, stir at room temperature for 1 hour, then add 80g of acetophenone, add 10wt% hydrochloric acid to adjust the pH to 4.5, reflux at 85℃ and stir for 8 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0035] Example 4

[0036] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0037] Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH to 4.5, reflux at 85℃ and stir for 8 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0038] Example 5

[0039] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0040] (1) Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH value to 4.5, reflux at 85℃ and stir for 8 hours to obtain the corrosion inhibitor body.

[0041] (2) Add 50g butynediol and 40g sodium lignosulfonate to 1000g of corrosion inhibitor at room temperature and pressure, stir at 85°C for 0.5 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0042] Example 6

[0043] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0044] (1) Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH value to 4.5, reflux at 85℃ and stir for 8 hours to obtain the corrosion inhibitor body.

[0045] (2) Add 50g butynediol and 40g lauric acid diethanolamide to 1000g of corrosion inhibitor at room temperature and pressure, stir at 85°C for 0.5 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0046] Example 7

[0047] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0048] (1) Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH value to 4.5, reflux at 85℃ and stir for 8 hours to obtain the corrosion inhibitor body.

[0049] (2) Add 50g butynediol and 40g N,N-di(hydroxyethyl)cocamide to 1000g of corrosion inhibitor at room temperature and pressure, stir at 85°C for 0.5 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0050] Example 8

[0051] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0052] (1) Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH value to 4.5, reflux at 85℃ and stir for 8 hours to obtain the corrosion inhibitor body.

[0053] (2) Add 50g butynediol, 20g sodium lignosulfonate and 20g lauric acid diethanolamide to 1000g of corrosion inhibitor at room temperature and pressure, stir at 85°C for 0.5 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0054] Example 9

[0055] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0056] (1) Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH value to 4.5, reflux at 85℃ and stir for 8 hours to obtain the corrosion inhibitor body.

[0057] (2) Add 50g butynediol, 20g sodium lignosulfonate and 20g N,N-di(hydroxyethyl)cocamide to 1000g of corrosion inhibitor at room temperature and pressure, stir at 85°C for 0.5 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0058] Example 10

[0059] A method for preparing a high-temperature corrosion inhibitor for acidification includes the following steps:

[0060] (1) Add 120g N-acetylimidazole and 100g aniline to 700g anhydrous ethanol, stir at room temperature for 1 hour, then add 80g acetophenone, add 10wt% hydrochloric acid to adjust the pH value to 4.5, reflux at 85℃ and stir for 8 hours to obtain the corrosion inhibitor body.

[0061] (2) Add 50g butynediol, 20g N,N-di(hydroxyethyl)cocamide and 20g lauric acid diethanolamide to 1000g of corrosion inhibitor at room temperature and pressure, stir at 85°C for 0.5 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification.

[0062] Test Example 1

[0063] High temperature and high pressure dynamic corrosion rate

[0064] The test procedure was based on the high-temperature and high-pressure dynamic corrosion rate test method in the industry standard SY / T 5405-2019 "Test Method and Evaluation Index of Corrosion Inhibitors for Acidification". At a high temperature of 140℃, the high-temperature corrosion inhibitors for acidification prepared by the methods in Examples 1-10 were applied to 20wt% hydrochloric acid solution, and their corrosion rate was calculated. The average value of the data was taken and summarized as shown in Table 1.

[0065] The material for the hanging plate is N80 steel pipe. Heat treatment, forging, and hammering are strictly prohibited during processing. Grind the hanging plate with 400# metallographic sandpaper until the roughness is equal to 1.2. Hold it with tweezers, wash off the oil with acetone, soak it in anhydrous ethanol for 1 minute, take it out and let it dry. Put it in a desiccator for 20 minutes, weigh it (accurate to 0.0001g) and record the weight. Then store it in the desiccator for later use.

[0066] The corrosive acid medium is hydrochloric acid solution with a mass fraction of 20 wt%. The corrosion inhibitor dosages are 1.5 wt% and 3.0 wt% of the hydrochloric acid solution, respectively. The acid dosage is 20 cm³ per square centimeter of the surface area of ​​the coated plate. 3 Pour the acid solution into the autoclave, suspend the plate on the plate holder, install and tighten the stirring, sealing, and plate holder components, and connect the pipeline; turn on the power of the measuring instrument and set the heating program to 140℃; open the high-pressure nitrogen source valve, adjust the pressure valve, and start the pump to maintain a pressure of 12MPa inside the autoclave; control the instrument's heating rate at 3-4℃ / min; when the acid solution temperature reaches 140℃, adjust the pressure of the reaction vessel to the required pressure for the measurement through the pressure relief valve, start the stirring motor, and adjust it to the required speed for the measurement; start timing when the acid solution reaches 140℃; after soaking for 4 hours, stop heating and stirring, stop timing, and start the condenser to cool down; when the temperature drops to 80℃, depressurize the reaction vessel, discharge the residual acid, remove the plate, clean it with acetone and ethanol, dry it, weigh it, and calculate the corrosion rate.

[0067] The corrosion rate formula is as follows:

[0068] υ i =10 6 △m i / A i ·△t

[0069] υ i —Single-piece corrosion rate, in grams per square meter per hour [g / (m²)] 2 ·h)];

[0070] △t — Reaction time, in hours (h);

[0071] △m i —Corrosion loss of the coupon, in grams (g);

[0072] A i —Surface area of ​​the mounting plate, in square millimeters (mm) 2 ).

[0073] Table 1. Test data of dynamic corrosion rate under high temperature and high pressure

[0074]

[0075] In the high-temperature and high-pressure dynamic corrosion rate test of Example 1, the high-temperature corrosion inhibitors used for acidification in Examples 1-4 did not contain any synergists. The comparison showed that Example 4 exhibited the lowest corrosion rate for N80 steel pipes under a 140℃, 20wt% hydrochloric acid environment. In Examples 5-7, the high-temperature corrosion inhibitors used for acidification incorporated sodium lignosulfonate, lauric acid diethanolamide, and N,N-di(hydroxyethyl)cocoamide, respectively. Compared to Examples 5-7, Examples 8-10 were compounded. The comparison showed that the compounding effect of sodium lignosulfonate, lauric acid diethanolamide, and the main body of the corrosion inhibitor was the best. Under a 140℃, 20wt% hydrochloric acid environment, Example 8 showed the best corrosion inhibition effect when sodium lignosulfonate and lauric acid diethanolamide were combined. When the corrosion inhibitor dosage was 3.0wt%, the corrosion rate of N80 steel pipes under a 140℃, 20wt% hydrochloric acid environment was the lowest at 10.43 g / (m³). 2 ·h).

[0076] Test Example 2

[0077] stability

[0078] The high-temperature corrosion inhibitors for acidification prepared by the methods in Examples 5-10 were stored in 20wt% hydrochloric acid solution for 24 hours. Storage stability tests were conducted at temperatures of 90℃, 120℃, and 140℃, with the amounts of the high-temperature corrosion inhibitors added being 1wt%, 2wt%, and 3wt%, respectively. The presence of stratification, flocculation, or precipitation in the system was observed. If none of these phenomena occurred, it was marked as "-"; if any one of them occurred, it was marked as "+"; if two or more of them occurred, it was marked as "++". The results are summarized in Table 2.

[0079] Table 1. Test data of dynamic corrosion rate under high temperature and high pressure

[0080]

[0081]

[0082] In Test Example 2, the high-temperature corrosion inhibitors for acidification from Examples 5-10 were placed at 90°C, 120°C, and 140°C for 24 hours, respectively. Storage stability tests were conducted with the inhibitors added at concentrations of 1.0 wt%, 2.0 wt%, and 3.0 wt%, respectively. The compatibility of the system was assessed by observing whether stratification, flocculation, or precipitation occurred. When the same amount of inhibitor was added in each set of examples, the probability of instability increased with increasing temperature. Conversely, when the same temperature was applied in each set of examples, the lower the amount of inhibitor added, the higher the probability of instability.

[0083] Comparison shows that in Examples 5-7, at different dosages and after being placed at 90°C for 24 hours, any one of the following phenomena occurred in the system: stratification, flocculation, or precipitation. In Examples 8-10, at different dosages and after being placed at 90°C for 24 hours, no unstable phenomena occurred in the system. In Examples 9-10, at different dosages and starting at 120°C, at least one of the following phenomena occurred in the system: stratification, flocculation, or precipitation. In Example 8, at dosages of 2wt% and 3wt%, no unstable phenomena occurred in the system at 90°C, 120°C, and 140°C. This indicates that when sodium lignosulfonate and lauric acid diethanolamide were mixed in Example 8, the system exhibited good thermal stability.

Claims

1. A method for preparing a high-temperature corrosion inhibitor for acidification, characterized in that, Includes the following steps: (1) Add N-acetylimidazole and aniline to anhydrous ethanol, stir at room temperature for 1-2 hours, then add acetophenone, add hydrochloric acid to adjust the pH to acidic, reflux and stir for 6-10 hours to obtain the corrosion inhibitor body; (2) Add butynediol, sodium lignosulfonate and lauric acid diethanolamide to the corrosion inhibitor at room temperature and pressure, stir at 80-90℃ for 0.5-1 hours, and cool to room temperature to obtain the high-temperature corrosion inhibitor for acidification; the weight ratio of N-acetylimidazole, aniline, acetophenone and anhydrous ethanol in step (1) is 1.0-1.5:1.0-2.0:0.5-1.5:6-10.

2. The method for preparing the high-temperature corrosion inhibitor for acidification as described in claim 1, characterized in that, In step (1), the pH value is adjusted to acidity, that is, the pH value is adjusted to 2-6.

3. The method for preparing the high-temperature corrosion inhibitor for acidification as described in claim 1, characterized in that, The condensation reflux temperature in step (1) is 80-90℃.

4. The method for preparing the high-temperature corrosion inhibitor for acidification as described in claim 1, characterized in that, In step (1), the weight ratio of N-acetylimidazole, aniline, acetophenone, and anhydrous ethanol is 1.0-1.2:1.0-1.2:0.8-1.0:6-8.

5. The method for preparing the high-temperature corrosion inhibitor for acidification as described in claim 1, characterized in that, In step (2), the weight ratio of the corrosion inhibitor, butynediol, sodium lignosulfonate, and diethanolamide laurate is 8-15. 0.2-1：0.1-0.5：0.1-0.5。 6. The method for preparing the high-temperature corrosion inhibitor for acidification as described in claim 1, characterized in that, In step (2), the weight ratio of the corrosion inhibitor, butynediol, sodium lignosulfonate, and diethanolamide laurate is 9-11: 0.5-1：0.2-0.4：0.2-0.4。 7. A high-temperature corrosion inhibitor for acidification, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

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