Acid gas corrosion inhibitor and its preparation method and application

Abstract

The present invention relates to the technical field of corrosion inhibitors and their preparation, and is an acid-resistant gas corrosion inhibitor and its preparation method and application. The former is obtained by the following method: the required amount of a first polymer and a second polymer are uniformly mixed and then compounded, wherein the first polymer is a linear imidazoline polymer prepared by reacting imidazoline with a dicarboxylic acid and a halogenated alkane, and the second polymer is a cationic linear structure imidazoline polymer prepared by reacting imidazoline with a chlorine-containing compound, guanidine hydrochloride, and a primary amine. In the present invention, n imidazoline rings in the molecule of the first polymer are adsorbed on a stainless steel pipe, thereby improving the adsorption capacity and scour resistance of the corrosion inhibitor. The second polymer increases the adsorption of imidazoline, and at the same time introduces a primary amine hydrophobic group to improve the hydrophobic ability of imidazoline. A guanidine structure is also introduced into the imidazoline structure, so that the product has a strong bactericidal effect and can be widely used in corrosion protection, sterilization, and scale inhibition of oil and gas wells.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion inhibitors and preparation thereof, in particular to an acid gas resistant corrosion inhibitor and a preparation method and application thereof. Background Art

[0002] CO2-H2S corrosion has long been a thorny issue and a research hotspot in the oil industry. The equipment and pipeline failures caused by CO2-H2S corrosion have resulted in significant economic losses and serious social consequences. Therefore, research into inhibiting CO2-H2S corrosion has far-reaching economic and social implications. Corrosion, scaling, and bacterial growth are common problems in oilfield development and pipeline transportation, and if not effectively controlled, they can severely impact oilfield production.

[0003] Imidazoline corrosion inhibitors have excellent corrosion inhibition properties. The inhibition rate increases with increasing inhibitor concentration. When the concentration of N-alkylbenzimidazolinium cationic corrosion inhibitor is 50 mg / L, the inhibition rate reaches 97.15%. In recent years, there has been considerable research on the use of imidazoline corrosion inhibitors to address CO2-H2S corrosion. By forming a monomolecular adsorption film on the metal surface during contact with the acidic medium, the metal's potential is reduced, achieving corrosion inhibition.

[0004] Chinese patent publication CN116497359A discloses an acid gas corrosion inhibitor comprising 10-15 parts of phosphinocarboxylic acid, 20-30 parts of mercaptobenzothiazole, 10-20 parts of benzotriazole, 15-30 parts of sulfonated lignin, 10-15 parts of ammonium benzoate, and 1-10 parts of distilled water, which are sequentially added to a stirred tank for preheating, stirring, heating, and cooling. However, the prior art simply compounded the corrosion inhibitor, scale inhibitor, and fungicide before adding them. This not only results in relatively high reagent costs, but also poses a major technical challenge in terms of product compatibility.

[0005] Therefore, it is necessary to develop an anti-acid gas corrosion inhibitor with excellent corrosion protection, sterilization and scale inhibition effects for use in oil field development. Summary of the Invention

[0006] The present invention provides an acid gas resistant corrosion inhibitor and a preparation method and application thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of high agent cost and incompatibility of agents in existing imidazoline corrosion inhibitors, which lead to poor product performance.

[0007] One of the technical solutions of the present invention is achieved through the following measures: a method for preparing an anti-acidic gas corrosion inhibitor is carried out according to the following method: the required amount of a first polymer and a second polymer are uniformly mixed and then compounded, wherein the first polymer is a linear imidazoline polymer prepared by a condensation reaction of imidazoline, and the second polymer is a cationic linear structure imidazoline polymer prepared by a condensation reaction of imidazoline.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0009] The first polymer is obtained according to the following method:

[0010] S1, mixing a required amount of dicarboxylic acid and polyamine and reacting them to obtain intermediate 1;

[0011] S2, mixing the intermediate 1 with a desired amount of dicarboxylic acid and reacting the mixture to obtain the intermediate 2;

[0012] S3, mixing the intermediate 2 with a required amount of halogenated alkane and reacting the mixture to obtain a first polymer.

[0013] In the above step S1, the molar ratio of dicarboxylic acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250° C. to 300° C., and the reaction time is 9 h to 11 h, wherein the polyamine is polyethylene polyamine.

[0014] In the above step S2, the molar ratio of the intermediate 1 to the dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145° C. to 155° C., and the reaction time is 2.5 h to 3.5 h.

[0015] In the above step S3, the halogenated alkane is one of brominated dodecane, brominated hexadecane, chlorododecane, and chlorohexadecane.

[0016] The second polymer is obtained according to the following method:

[0017] S11, reacting a required amount of the intermediate 1 obtained in step S1 with a chlorine-containing compound to obtain an intermediate 3;

[0018] S12, mixing the intermediate 3 with a required amount of guanidine hydrochloride and a primary amine and reacting the mixture to obtain a second polymer.

[0019] In the above step S11, the molar ratio of the intermediate 1 to the chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70° C. to 100° C., the reaction time is 2.5 h to 3.5 h, and the chlorine-containing compound is 1,4-dichlorobenzyl.

[0020] In the above step S12, the molar ratio of intermediate three to guanidine hydrochloride and primary amine is 0.9 to 1.1:1.5 to 2:1.5 to 2, the reaction temperature is 145° C. to 155° C., the reaction time is 3.5 h to 4.5 h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0021] The second technical solution of the present invention is achieved through the following measures: a method for preparing an acid-resistant gas corrosion inhibitor to obtain an acid-resistant gas corrosion inhibitor.

[0022] The third technical solution of the present invention is achieved through the following measures: application of an acid-resistant gas corrosion inhibitor in oil and gas well corrosion protection, sterilization and scale inhibition.

[0023] In the present invention, n imidazoline rings are adsorbed on the stainless steel pipe in the molecule of the first polymer, thereby improving the adsorption capacity and scour resistance of the corrosion inhibitor. The second polymer increases the adsorption of imidazoline and introduces a primary amine hydrophobic group to improve the hydrophobicity of imidazoline. A guanidine structure is also introduced into the imidazoline structure, so that the product has a strong bactericidal effect and can be widely used in corrosion protection, sterilization, and scale inhibition of oil and gas wells. DETAILED DESCRIPTION

[0024] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art.

[0025] The present invention will be further described below in conjunction with the embodiments:

[0026] Example 1: The preparation method of the anti-acidic gas corrosion inhibitor is carried out according to the following method: the required amount of the first polymer and the second polymer are evenly mixed and compounded, wherein the first polymer is a linear imidazoline polymer prepared by a condensation reaction of imidazoline, and the second polymer is a cationic linear structure imidazoline polymer prepared by a condensation reaction of imidazoline.

[0027] Example 2: As an optimization of the above example, the first polymer is obtained according to the following method:

[0028] S1, mixing a required amount of dicarboxylic acid and polyamine and reacting them to obtain intermediate 1;

[0029] S2, mixing the intermediate 1 with a desired amount of dicarboxylic acid and reacting the mixture to obtain the intermediate 2;

[0030] S3, mixing the intermediate 2 with a required amount of halogenated alkane and reacting the mixture to obtain a first polymer.

[0031] The chemical reaction mechanism for obtaining intermediate 1 in the present invention is as follows:

[0032]

[0033] The chemical reaction mechanism to obtain intermediate 2 is as follows:

[0034]

[0035] The chemical reaction mechanism to obtain the first polymer is as follows:

[0036]

[0037] Example 3: As an optimization of the above example, in step S1, the molar ratio of dicarboxylic acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 9h to 11h, wherein the polyamine is polyethylene polyamine.

[0038] Example 4: As an optimization of the above example, in step S2, the molar ratio of intermediate 1 to dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145°C to 155°C, and the reaction time is 2.5h to 3.5h.

[0039] Example 5: As an optimization of the above example, in step S3, the halogenated alkane is one of brominated dodecane, brominated hexadecane, chlorododecane, and chlorohexadecane.

[0040] Example 6: As an optimization of the above example, the second polymer is obtained according to the following method:

[0041] S11, reacting a required amount of the intermediate 1 obtained in step S1 with a chlorine-containing compound to obtain an intermediate 3;

[0042] S12, mixing the intermediate 3 with a required amount of guanidine hydrochloride and a primary amine and reacting the mixture to obtain a second polymer.

[0043] The chemical reaction mechanism for obtaining intermediate three in the present invention is as follows:

[0044]

[0045] The chemical reaction mechanism to obtain the second polymer is as follows:

[0046]

[0047] Example 7: As an optimization of the above example, in step S11, the molar ratio of intermediate 1 to the chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70°C to 100°C, the reaction time is 2.5h to 3.5h, and the chlorine-containing compound is 1,4-dichlorobenzyl.

[0048] Example 8: As an optimization of the above example, in step S12, the molar ratio of intermediate three to guanidine hydrochloride and primary amine is 0.9 to 1.1:1.5 to 2:1.5 to 2, the reaction temperature is 145°C to 155°C, the reaction time is 3.5h to 4.5h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0049] Example 9: The resistant acid gas corrosion inhibitor obtained by the preparation method of the resistant acid gas corrosion inhibitor.

[0050] Example 10: Application of the anti-acid gas corrosion inhibitor in oil and gas well corrosion protection, sterilization, and scale inhibition.

[0051] Example 11: The preparation method of the acid gas corrosion inhibitor is carried out according to the following method:

[0052] In the first step, 146 kg (1 kmol) of adipic acid and 878 kg (2 kmol) of polyethylene polyamine (molecular weight 439) were added to a reactor, mixed evenly, and then slowly heated to 280°C and refluxed for 10 hours to obtain intermediate 1.

[0053] In the second step, the intermediate 1 was mixed evenly with 146 kg (1 kmol) of adipic acid, and the mixture was reacted at 150°C for 3 hours to obtain the intermediate 2.

[0054] In the third step, 249 kg (1 kmol) of bromododecane was added to the intermediate 2, and the reaction was controlled at 80°C for 4 hours to obtain the first polymer;

[0055] Step 4: Take 1024 kg of intermediate 1, add 175 kg (1 kmol) of 1,4-dichlorobenzyl, and react at 80 ° C for 4 hours to prepare intermediate 3;

[0056] Step 5: Add 191 kg of guanidine hydrochloride (2 kmol) and 429 kg of hexadecyl primary amine (2 kmol) to the intermediate 3, control the temperature at 150°C and react for 4 hours to prepare a second polymer;

[0057] In the sixth step, the first polymer and the second polymer are mixed in a mass ratio of 1:1, and stirred evenly to obtain an acid gas corrosion inhibitor.

[0058] Example 12: The preparation method of the acid gas corrosion inhibitor is different from that of Example 11 in that:

[0059] In the fifth step, 429 kg of hexadecyl primary amine was replaced with 370.6 kg of dodecyl primary amine;

[0060] The rest of the process is the same.

[0061] Example 13: The preparation method of the acid gas corrosion inhibitor is different from that of Example 11 in that:

[0062] In the second step, 146 kg of adipic acid was replaced with 174 kg of suberic acid;

[0063] The rest of the process is the same.

[0064] Example 14: The preparation method of the acid gas corrosion inhibitor is different from that of Example 11 in that:

[0065] In the third step, 249 kg of brominated dodecane was replaced with 205 kg of chlorododecane;

[0066] The rest of the process is the same.

[0067] Example 15: The preparation method of the acid gas corrosion inhibitor is different from that of Example 11 in that:

[0068] In the third step, 249 kg of dodecane bromide was exchanged for 261 kg of hexadecane chloride;

[0069] The rest of the process is the same.

[0070] The performance test and evaluation of the acid gas corrosion inhibitor obtained according to Examples 11 to 15 are as follows:

[0071] (1) Evaluation of bactericidal performance

[0072] According to SY / T5890 "Evaluation Method for Bactericide Performance", the extinction dilution method was used to determine the bactericidal effect of the acid-resistant gas corrosion inhibitor on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria. The addition concentration of the acid-resistant gas corrosion inhibitor of the present invention was 1%.

[0073] Comparative Example 1: using a monoguanidine fungicide.

[0074] ((Bacteria test bottle SRB (sulfate-reducing bacteria) readings, IB (iron bacteria) readings, TGB (saprophytic bacteria) readings) Experimental results are shown in Table 1.

[0075] Table 1

[0076] .

[0077] It can be seen from Table 1 that the bactericidal performance of the acid gas resistant corrosion inhibitor of the present invention is slightly better than that of the monoguanidine bactericide on the market.

[0078] (2) Corrosion inhibition experiment

[0079] Referring to the SYT5273 standard for the performance evaluation method of corrosion inhibitors for oilfield produced water reinjection water, six 1L stoppered bottles were added with oilfield water source well water and 1% of an acid gas corrosion inhibitor (Examples 11 to 15) to adjust the volume to 1L. The prepared N80 hanging plate (with an outer size of 40mm×13mm×2mm, a circular hole drilled in the middle of one end 5mm from the edge, and a surface area of ​​12cm) was hung. 2 ) and introduced CO2 and H2S to saturation to simulate the operating conditions in acidic oil and gas wells. The samples were then placed in a constant temperature oven at 90°C for 14 days. The coupons were removed, the corrosion products on the surface cleaned, and then dried with cold air and weighed. The corrosion rate of the steel coupons was calculated using formula (1). The results are shown in Table 2.

[0080] Formula (1)

[0081] Among them, γ c is the corrosion rate, in mm / a; ω0 is the initial mass of the coupon, in g; ω1 is the mass of the coupon at the end of the experiment, in g; S is the surface area of ​​the coupon, in cm 2 ; t is the reaction time, in h; ρ is g / cm 3 .

[0082] Blank Example: CO2 and H2S were introduced into the oilfield water source well water until saturation, without adding the acid gas corrosion inhibitor of the present invention. The remaining steps were consistent with the above steps. The results are shown in Table 2.

[0083] Comparative Example 1: using oleic acid imidazoline corrosion inhibitor.

[0084] Table 2

[0085] .

[0086] It can be seen from Table 2 that the acid gas resistant corrosion inhibitor of the present invention has excellent corrosion inhibition performance, and its corrosion inhibition performance is better than that of oleic acid imidazoline.

[0087] Corrosion and sterilization tests show that the acid gas corrosion inhibitor of the present invention has a good corrosion inhibition effect under simulated working conditions, with a corrosion inhibition rate of less than 0.05 mm / a, which is far lower than the corresponding industry standard. The sterilization rate meets the industry standard and has a good protective function for the inner wall of the casing in the annular space and the outer wall of the oil and gas pipeline in the acidic environment, thereby extending the service life and ensuring safe production in the oil field.

[0088] In summary, in the molecule of the first polymer in the present invention, n imidazoline rings are adsorbed on the stainless steel pipe, which improves the adsorption capacity and erosion resistance of the corrosion inhibitor. The second polymer increases the adsorption of imidazoline and introduces primary amine hydrophobic groups to improve the hydrophobic ability of imidazoline. A guanidine structure is also introduced into the imidazoline structure, which makes the product have a strong bactericidal effect and can be widely used in corrosion protection, sterilization, and scale inhibition of oil and gas wells.

[0089] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A method for preparing an acid gas corrosion inhibitor, characterized in that The method is as follows: the required amount of the first polymer and the second polymer are mixed uniformly and then compounded to obtain: The first polymer is obtained as follows: S1, mixing a required amount of dicarboxylic acid and polyamine and reacting them to obtain an intermediate 1, wherein the molar ratio of dicarboxylic acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250° C. to 300° C., and the reaction time is 9 h to 11 h, wherein the polyamine is polyethylene polyamine; S2, mixing the intermediate 1 with a desired amount of dicarboxylic acid and reacting to obtain the intermediate 2, wherein the molar ratio of the intermediate 1 to the dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145° C. to 155° C., and the reaction time is 2.5 h to 3.5 h; S3, mixing the intermediate 2 with a desired amount of a halogenated alkane and reacting the mixture to obtain a first polymer, wherein the halogenated alkane is one of brominated dodecane, brominated hexadecane, chlorododecane, and chlorohexadecane; The second polymer was obtained as follows: S11, reacting a required amount of the intermediate 1 obtained in step S1 with a chlorine-containing compound to obtain an intermediate 3, wherein the molar ratio of the intermediate 1 to the chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70° C. to 100° C., the reaction time is 2.5 h to 3.5 h, and the chlorine-containing compound is 1,4-dichlorobenzyl; S12, mixing the intermediate three with the required amount of guanidine hydrochloride and primary amine and reacting them to obtain a second polymer, wherein the molar ratio of the intermediate three to guanidine hydrochloride and primary amine is 0.9 to 1.1:1.5 to 2:1.5 to 2, the reaction temperature is 145° C. to 155° C., the reaction time is 3.5 h to 4.5 h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

2. An acid-resistant gas corrosion inhibitor obtained by the preparation method according to claim 1.

3. Use of the anti-acid gas corrosion inhibitor according to claim 2 in corrosion protection, sterilization and scale inhibition of oil and gas wells.

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