Corrosion inhibitor and use thereof

Abstract

The application provides an inhibitor and application thereof. Raw materials for preparing the inhibitor include organic amine, imidazoline polyether, quaternary ammonium salt, thiourea, benzotriazole, dispersant and solvent. The inhibitor provided by the application has synergistic effect among the components, provides film forming property of the inhibitor and compatibility among the components, so that the inhibitor can not be detached under high temperature condition, and thus can prevent corrosion of acidic gases such as CO2 and H2S on downhole pipe column, ground pipeline, equipment and the like, and guarantee normal production operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of corrosion inhibitors, in particular to a corrosion inhibitor and application thereof. BACKGROUND

[0002] Corrosion inhibitor refers to a chemical substance or compound that can prevent or slow down the corrosion of materials when existing in the environment in proper concentration and form, and therefore corrosion inhibitor can also be called corrosion inhibitor. In the process of oil field and natural gas exploitation or transportation, microorganisms and CO2, H2S and other acid gases seriously corrode downhole pipe strings, ground pipelines, equipment and the like, which seriously affects normal production operations. A large amount of liquid water is accumulated in the wellbore, and liquid water or water vapor is left at different positions of the wellbore. When the thickness of the water film reaches the critical relative humidity of the steel material, the corrosion medium CO2, H2S and other acid gases dissolved in the water film can form an effective electron transfer, causing corrosion of the steel material.

[0003] In order to prevent corrosion caused by acid gases, common corrosion prevention measures mainly include using corrosion-resistant pipe materials, surface protective coverings or plating layers, adding corrosion inhibitors, and process corrosion prevention, among which the most economical and fastest-acting method is to use corrosion inhibitors. Some corrosion inhibitors have certain corrosion inhibition effect on acid gases, but when the temperature is slightly higher than 70℃, they will be desorbed, greatly reducing the efficiency of the corrosion inhibitors or even making them ineffective. SUMMARY

[0004] The present application provides a corrosion inhibitor, and raw materials for preparing the corrosion inhibitor include organic amine, imidazoline polyether, quaternary ammonium salt, thiourea, benzotriazole, dispersant and solvent.

[0005] In one specific embodiment, the organic amine is alkylamine.

[0006] In one specific embodiment, the alkylamine is N-octadecyl propylene diamine. For example, the CAS number of N-octadecyl propylene diamine is 7173-62-8.

[0007] In one specific embodiment, the imidazoline polyether is imidazoline polyoxyethylene ether RX-406.

[0008] In one specific embodiment, the quaternary ammonium salt is a mixture of alkyl imidazoline quaternary ammonium salt and quinoline quaternary ammonium salt.

[0009] In one specific embodiment, the quaternary ammonium salt is a mixture of alkyl imidazoline quaternary ammonium salt and quinoline quaternary ammonium salt at a mass ratio of 1:2.

[0010] In one specific embodiment, the dispersant is a mixture of tetradecyl phosphoric acid diester and fatty acid polyethylene glycol ester.

[0011] In one embodiment, the dispersant is a mixture of tetradecylphosphonic acid di-ester and fatty acid polyglycol ester in a mass ratio of 2:1.

[0012] In one embodiment, the CAS number of tetradecylphosphonic acid di-ester is 6640-03-5, and the trade name of fatty acid polyglycol ester is PEG400DS.

[0013] In one embodiment, the solvent is methanol.

[0014] In one embodiment, the organic amine is 1-2 parts by mass, the imidazoline polyether is 15-25 parts by mass, the quaternary ammonium salt is 20-30 parts by mass, the thiourea is 5-10 parts by mass, the benzotriazole is 1-5 parts by mass, the dispersant is 5-10 parts by mass, and the solvent is 60-70 parts by mass.

[0015] In one embodiment, the alkyl imidazoline quaternary ammonium salt is prepared by the following steps:

[0016] 1) mixing caprylic acid and diethylenetriamine uniformly, and reacting at high temperature to obtain 1-aminoethyl-2-octyl imidazoline;

[0017] 2) mixing 1-aminoethyl-2-octyl imidazoline and benzyl chloride uniformly, and reacting at high temperature to obtain the alkyl imidazoline quaternary ammonium salt.

[0018] In one embodiment, the alkyl imidazoline quaternary ammonium salt is prepared by the following steps:

[0019] 1) mixing caprylic acid and diethylenetriamine in a molar ratio of 1:1.4 uniformly, and reacting at 170°C for 3h to obtain 1-aminoethyl-2-octyl imidazoline;

[0020] 2) mixing 1-aminoethyl-2-octyl imidazoline and benzyl chloride in a molar ratio of 1:1.2 uniformly, and reacting at 170°C for 3.5h to obtain the alkyl imidazoline quaternary ammonium salt.

[0021] In one embodiment, the quinoline quaternary ammonium salt is prepared by the following steps:

[0022] stirring quinoline and benzyl chloride, then reacting at high temperature, and cooling to ambient temperature after the reaction to obtain the quinoline quaternary ammonium salt.

[0023] In one embodiment, the quinoline quaternary ammonium salt is prepared by the following steps:

[0024] stirring quinoline and benzyl chloride in a molar ratio of 1:1 for 10min, then reacting at 165°C for 8h, and cooling to ambient temperature after the reaction to obtain the quinoline quaternary ammonium salt.

[0025] The second aspect of the present application provides the use of the corrosion inhibitor according to any one of the first aspects of the present application for preventing or reducing acid gas corrosion at high temperature.

[0026] In one embodiment, the high temperature is a temperature of 70℃ or higher.

[0027] In one embodiment, the high temperature is a temperature of 70℃ or higher and 100℃ or lower.

[0028] Advantages of the present application:

[0029] The corrosion inhibitor provided by the present application has synergistic effect among the components, provides film-forming property of the corrosion inhibitor and compatibility among the components, thereby ensuring that the corrosion inhibitor does not desorb at high temperature, and thus preventing corrosion of CO2, H2S and other acid gases to downhole pipe strings and ground pipelines, equipment and the like, and ensuring normal production operation. DETAILED DESCRIPTION

[0030] The present application will be further described below in conjunction with examples, but the examples of the present application are only exemplary description, and the embodiment does not constitute a limitation on the present application in any case.

[0031] The preparation of the alkyl imidazoline quaternary ammonium salt includes the following steps:

[0032] (1) A molar ratio of 1:1.4 of octanoic acid and diethylene triamine is added to a reaction kettle, the mixture of octanoic acid and diethylene triamine is stirred until uniform, and then reacted at 170℃ for 3h to obtain 1-aminoethyl-2-octyl imidazoline;

[0033] (2) The 1-aminoethyl-2-octyl imidazoline is added to another reaction kettle, then benzyl chloride is added and stirred until uniform, and then reacted at 170℃ for 3.5h to obtain the alkyl imidazoline quaternary ammonium salt, wherein the molar ratio of 1-aminoethyl-2-octyl imidazoline to benzyl chloride is 1:1.2.

[0034] The preparation of the quinoline quaternary ammonium salt includes the following steps:

[0035] A molar ratio of 1:1 of quinoline and benzyl chloride is added to a round-bottom flask, stirred for 10min, and then reacted at 165℃ for 8h, and then cooled to ambient temperature after the reaction to obtain the quinoline quaternary ammonium salt.

[0036] Example 1

[0037] The raw materials for preparing the liquid corrosion inhibitor include, by mass fraction, 1 part of organic amine, 15 parts of imidazoline polyether, 20 parts of quaternary ammonium salt, 5 parts of thiourea, 1 part of benzotriazole, 5 parts of dispersant and 60 parts of solvent.

[0038] The organic amine is N-octadecyl propylene diamine, purchased from Hangzhou Fanda Chemical Co., Ltd., with CAS number 7173-62-8.

[0039] The imidazoline polyether is imidazoline polyoxyethylene ether, purchased from Shaanxi Rixin Petrochemical Co., Ltd., with brand RX-406.

[0040] The quaternary ammonium salt is a mixture of alkyl imidazoline quaternary ammonium salt and quinoline quaternary ammonium salt with a mass ratio of 1:2.

[0041] The dispersant is a mixture of tetradecyl phosphoric acid diester (CAS number 6640-03-5) and fatty acid polyethylene glycol ester (purchased from Haian Petrochemical Co., Ltd. in Jiangsu Province, with brand PEG400DS) with a mass ratio of 2:1.

[0042] The solvent is methanol.

[0043] The preparation method of the liquid corrosion inhibitor comprises the following steps: sequentially adding tetradecyl phosphoric acid diester, fatty acid polyethylene glycol ester, alkyl imidazoline quaternary ammonium salt, quinoline quaternary ammonium salt, thiourea, benzotriazole, N-octadecyl propylene diamine and imidazoline polyoxyethylene ether in a methanol solvent, and stirring to obtain the liquid corrosion inhibitor.

[0044] Example 2

[0045] The difference from Example 1 is that the organic amine is 1.5 parts, the imidazoline polyether is 20 parts, the quaternary ammonium salt is 25 parts, the thiourea is 8 parts, the benzotriazole is 3 parts, the dispersant is 7 parts and the solvent is 65 parts.

[0046] Example 3

[0047] The difference from Example 1 is that the organic amine is 2 parts, the imidazoline polyether is 25 parts, the quaternary ammonium salt is 30 parts, the thiourea is 10 parts, the benzotriazole is 5 parts, the dispersant is 10 parts and the solvent is 70 parts.

[0048] Comparative Example 1

[0049] The difference from Example 1 is that the mass ratio of alkyl imidazoline quaternary ammonium salt to quinoline quaternary ammonium salt in the quaternary ammonium salt is 1:6.

[0050] Comparative Example 2

[0051] The difference from Example 1 is that the mass ratio of alkyl imidazoline quaternary ammonium salt to quinoline quaternary ammonium salt in the quaternary ammonium salt is 4:1.

[0052] Comparative Example 3

[0053] The difference from Example 1 is that the dispersant is only fatty acid polyethylene glycol, without tetradecyl phosphoric acid diester.

[0054] Performance test

[0055] 1. The corrosion inhibition efficiency of the corrosion inhibitors prepared in Examples 1-3 and Comparative Examples 1-3 was determined according to the standard SY / T5405-1996 "Performance Test Method and Evaluation Index of Corrosion Inhibitors for Acidification": the corrosion medium was 20% hydrochloric acid solution, the mass fraction of the corrosion inhibitor was 4%, the steel sheet type was N80, the reaction temperature was 100°C, the reaction time was 4h, and no corrosion inhibitor was added in the blank control. The test results are shown in Table 1.

[0056] 2. The stability of the corrosion inhibitors prepared in Examples 1-3 and Comparative Examples 1-3 was determined by standing the corrosion inhibitors for 8h and visually observing whether the corrosion inhibitors were homogeneous solutions. The test results are shown in Table 1.

[0057] Table 1

[0058] Corrosion inhibitor Corrosion rate / (g · (m 2 ·h) -1 )]]> Corrosion inhibition efficiency (%) Stability Blank control 52.13 / / Example 1 1.25 99.50 Homogeneous solution Example 2 1.00 99.65 Homogeneous solution Example 3 1.43 99.43 Homogeneous solution Comparative Example 1 7.63 97.53 Homogeneous solution Comparative Example 2 9.54 95.88 Homogeneous solution Comparative Example 3 22.75 92.40 Homogeneous solution

[0059] It can be seen from the above data that certain alkyl imidazoline quaternary ammonium salts and quinoline quaternary ammonium salts, in combination with suitable dispersants, have good synergistic effect, and thus exhibit higher corrosion inhibition efficiency.

[0060] Although the present application has been described with reference to specific embodiments, it is understood that various changes can be made without departing from the true spirit and scope of the application. In addition, various changes can be made to the subject matter, spirit and scope of the application to adapt it to various situations, materials, compositions of matter and methods. All such changes are intended to be included within the scope of the claims of the present application.

Claims

1. A corrosion inhibitor, wherein the raw materials for its preparation include organic amine, imidazoline polyether, quaternary ammonium salt, thiourea, benzotriazole, dispersant and solvent; The quaternary ammonium salt is a mixture of alkyl imidazoline quaternary ammonium salt and quinoline quaternary ammonium salt in a mass ratio of 1:2; The dispersant is a mixture of tetradecyl phosphate diester and fatty acid polyethylene glycol ester in a mass ratio of 2:

1.

2. The corrosion inhibitor according to claim 1, characterized in that, The organic amine is an alkylamine.

3. The corrosion inhibitor according to claim 1, characterized in that, The organic amine is N-octadecylpropylene diamine.

4. The corrosion inhibitor according to claim 1, characterized in that, The imidazoline polyether is imidazoline polyoxyethylene ether RX-406.

5. The corrosion inhibitor according to claim 1, characterized in that, The solvent is methanol.

6. The corrosion inhibitor according to claim 1, characterized in that, The organic amine comprises 1 to 2 parts by weight, the imidazoline polyether comprises 15 to 25 parts by weight, the quaternary ammonium salt comprises 20 to 30 parts by weight, the thiourea comprises 5 to 10 parts by weight, the benzotriazole comprises 1 to 5 parts by weight, the dispersant comprises 5 to 10 parts by weight, and the solvent comprises 60 to 70 parts by weight.

7. The corrosion inhibitor according to any one of claims 1 to 6, used to prevent or reduce corrosion by acidic gases at high temperatures; The high temperature refers to a temperature above 70°C.

8. The application according to claim 7, characterized in that, The high temperature is defined as a temperature above 70°C and below 100°C.