An ethoxylated modified multi-hydrophobic corrosion inhibitor and its preparation method

Abstract

This invention discloses an ethoxylated modified hydrophobic corrosion inhibitor and its preparation method. The method comprises the following steps: Alkylamine and long-chain alkenyl acid are mixed in a molar ratio of 1:(1-3) to obtain a hydrophobic compound A; a double bond sulfonate compound is mixed with hydrophobic compound A in a molar ratio of 1:(1-3) to obtain polymer B; a catalyst is added to polymer B, the temperature is raised to 140°C, a vacuum is drawn, and ethylene oxide is introduced, with a molar ratio of ethylene oxide to polymer B of (10-20):1, to obtain an ethoxylated modified hydrophobic compound C; ethoxylated modified hydrophobic compound C is mixed with DTC salt, sodium mercaptoacetate solution, mercaptoethanol, and water in a mass ratio of 20:20:5:3:52 and stirred until homogeneous to obtain the corrosion inhibitor. The corrosion inhibitor of this invention has the characteristics of low corrosion rate control, stable properties, and good compatibility.

Description

Technical Field

[0001] This invention relates to the field of corrosion and protection technology in oil, gas and water treatment, and particularly to an ethoxylated modified multi-hydrophobic corrosion inhibitor and its preparation method. Background Technology

[0002] As oilfield exploitation continues, the water content of produced fluids increases daily. To effectively prevent metal corrosion in the environmental medium and extend the service life of metals, the addition of corrosion inhibitors has become an essential chemical method. The corrosion inhibitors, added with the flow of water, enter various parts of the production system, protecting the metal materials. Through the adsorption groups such as nitrogen, oxygen, sulfur, and phosphorus on the corrosion inhibitor, lone pairs of electrons are provided to form coordinate bonds with empty d orbitals on the metal surface. Polar groups, due to their strong charge transfer effect, preferentially adsorb onto the metal surface, while non-polar alkyl long chains are separated from the metal surface, forming a close-packed hydrophobic film.

[0003] Currently, imidazoline and imidazoline quaternary ammonium salts are the main corrosion inhibitors used in offshore oil fields. These inhibitors generally exhibit high solubility in oil but low solubility in water. Excessive solubility in oil reduces the inhibitor's efficiency, increases the dosage, and raises application costs. Furthermore, imidazoline and its quaternary ammonium salts have poor compatibility, reacting with cleaning agents, scale inhibitors, and other agents, leading to precipitation and other problems when mixed in large quantities. Adding them to the on-site dosage concentration can also reduce the inhibitor's effectiveness or even cause it to fail. Summary of the Invention

[0004] To address the problems of low water solubility and poor compatibility of existing corrosion inhibitors, this invention provides an ethoxylated modified multi-hydrophobic corrosion inhibitor and its preparation method. This method alters and adjusts the molecular structure of the corrosion inhibitor through ethoxylation and synergistically combines it with nitrogen- and sulfur-containing small-molecule synergists, resulting in high water solubility, compatibility, salt resistance, and corrosion inhibition efficiency in the corrosive environment of offshore oil fields.

[0005] In a first aspect, the present invention provides a method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor, which is achieved by the following technical solution.

[0006] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0007] S1. Mix alkylamine and long-chain alkenyl acid in a molar ratio of 1:(1-3) and stir. React at 140℃-160℃ for 4-5 hours to obtain polyhydrophobic compound A.

[0008] S2. Mix the double bond sulfonate compound and the polyhydrophobic compound A obtained in step S1 at a molar ratio of 1:(1-3), and react at 120℃-140℃ for 4-5 hours to obtain polymer B.

[0009] S3. Add a catalyst to polymer B obtained in step S2, heat to 130℃-150℃, remove oxygen by vacuum, slowly introduce ethylene oxide, the molar ratio of ethylene oxide to polymer B is (10-20):1, react for 4-6 hours to obtain ethoxylated modified hydrophobic compound C.

[0010] S4. The ethoxylated modified hydrophobic compound C obtained in step S3 is mixed with DTC salt (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%), and water in a mass ratio of 10-20:5-20:1-5:1-3:52-83 and stirred until homogeneous to obtain a corrosion inhibitor.

[0011] Furthermore, in step S1, the alkylamine is selected from one of octadeceneamine, N-oleo-1,3-propanediamine, and N-oleo-dipropanetriamine.

[0012] Furthermore, in step S1, the long-chain alkenyl acid is selected as tetradecenyl succinic acid.

[0013] Furthermore, in step S2, the double bond sulfonate compound is selected from sodium 2-acrylamido-2-methylpropanesulfonate or sodium allyl sulfonate.

[0014] Furthermore, in step S3, the catalyst is selected from potassium hydroxide or sodium formate.

[0015] Furthermore, in step S3, the amount of catalyst added is 0.2%-0.5% of the mass of polymer B.

[0016] Furthermore, in step S4, the DTC salt is sodium diethyldithiocarbamate.

[0017] Secondly, the present invention provides an ethoxylated modified multi-hydrophobic corrosion inhibitor, which is achieved by the following technical solution.

[0018] An ethoxylated modified hydrophobic corrosion inhibitor prepared by the above preparation method.

[0019] This application has the following beneficial effects.

[0020] The ethoxylated modified hydrophobic corrosion inhibitor of the present invention has multiple hydrophobic groups and strong surface activity. It can not only use the characteristics of multiple hydrophobic groups to isolate water from the corrosion of metals, but also use its strong surface activity to improve its water solubility and increase its effective concentration in water. The ethoxylated modified hydrophobic corrosion inhibitor has the characteristics of water solubility and good compatibility (especially with scale inhibitors and bactericides, it does not affect each other's performance). Detailed Implementation

[0021] The present patent application will be further described below with reference to the embodiments.

[0022] Unless otherwise specified, the experimental methods used in the following preparation examples and embodiments are conventional methods; the materials and reagents used in the following preparation examples and embodiments are commercially available unless otherwise specified.

[0023] Example 1

[0024] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0025] (1) Mix 53.5g of octadeceneamine with 29.4g of tetradecenyl succinic acid, heat to 60℃ and start stirring. React at 140℃ for 4h to obtain a multi-hydrophobic compound A1.

[0026] (2) The hydrophobic compound A1 obtained in step (1) was mixed with 41.4g of sodium 2-acrylamide-2-methylpropanesulfonate and reacted at 120℃ for 4h to obtain polymer B1.

[0027] (3) Add 0.25g of potassium hydroxide catalyst to polymer B1, heat to 130℃, remove oxygen by vacuum, slowly introduce 88g of ethylene oxide, react for 4h to obtain ethoxylated modified hydrophobic compound C1.

[0028] (4) The ethoxylated modified hydrophobic compound C1 obtained from the reaction is mixed with sodium diethyldithiocarbamate (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%) and water in a mass ratio of 20:20:5:3:52 and stirred evenly to obtain the corrosion inhibitor.

[0029] Example 2

[0030] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0031] (1) 65.2g of N-oleo-1,3-propanediamine and 29.4g of tetradecenyl succinic acid were mixed, heated to 60°C and stirred. The mixture was reacted at 150°C for 5 hours to obtain a multi-hydrophobic compound A2.

[0032] (2) The hydrophobic compound A2 obtained in step (1) was mixed with 41.4g of sodium 2-acrylamide-2-methylpropanesulfonate and reacted at 130℃ for 5h to obtain polymer B2.

[0033] (3) Add 0.3g of potassium hydroxide catalyst to polymer B2, heat to 150℃, remove oxygen by vacuum, slowly introduce 88g of ethylene oxide, react for 6h to obtain ethoxylated modified hydrophobic compound C2.

[0034] (4) The ethoxylated modified hydrophobic compound C2 obtained from the reaction is mixed with sodium diethyldithiocarbamate (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%) and water in a mass ratio of 20:10:5:3:62 and stirred evenly to obtain the corrosion inhibitor.

[0035] Example 3

[0036] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0037] (1) 76.2g of N-oleo-dipropylenetriamine and 29.4g of tetradecenyl succinic acid were mixed, heated to 60°C and stirred. The mixture was reacted at 150°C for 5 hours to obtain a multi-hydrophobic compound A3.

[0038] (2) The hydrophobic compound A3 obtained in step (1) was mixed with 41.4g of sodium 2-acrylamide-2-methylpropanesulfonate and reacted at 140℃ for 5h to obtain polymer B3.

[0039] (3) Add 0.35g of potassium hydroxide catalyst to polymer B3, heat to 150℃, remove oxygen by vacuum, slowly introduce 88g of ethylene oxide, react for 6h to obtain ethoxylated modified hydrophobic compound C3.

[0040] (4) The ethoxylated modified hydrophobic compound C3 obtained from the reaction is mixed with sodium diethyldithiocarbamate (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%) and water in a mass ratio of 20:20:5:3:52 and stirred evenly to obtain the corrosion inhibitor.

[0041] Example 4

[0042] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0043] (1) Mix 53.8g of octadeceneamine with 29.4g of tetradecenyl succinic acid, heat to 60°C and start stirring. React at 140°C for 4 hours to obtain a multi-hydrophobic compound A4.

[0044] (2) Mix the multi-hydrophobic compound A4 obtained in step (1) with 28.8g of sodium allyl sulfonate and react at 120℃ for 4h to obtain polymer B4.

[0045] (3) Add 0.25g of potassium hydroxide catalyst to polymer B4, heat to 130℃, remove oxygen by vacuum, slowly introduce 88g of ethylene oxide, react for 4h to obtain ethoxylated modified hydrophobic compound C4.

[0046] (4) The ethoxylated modified hydrophobic compound C4 obtained from the reaction is mixed with sodium diethyldithiocarbamate (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%) and water in a mass ratio of 20:15:5:2:58 and stirred evenly to obtain the corrosion inhibitor.

[0047] Example 5

[0048] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0049] (1) 65.2g of N-oleo-1,3-propanediamine and 29.4g of tetradecenyl succinic acid were mixed, heated to 60°C and stirred. The mixture was reacted at 160°C for 5 hours to obtain a multi-hydrophobic compound A5.

[0050] (2) Mix the multi-hydrophobic compound A5 obtained in step (1) with 28.8g of sodium allyl sulfonate and react at 140℃ for 5h to obtain polymer B5.

[0051] (3) Add 0.3g of potassium hydroxide catalyst to polymer B5, heat to 130℃, remove oxygen by vacuum, slowly introduce 88g of ethylene oxide, react for 5h to obtain ethoxylated modified hydrophobic compound C5.

[0052] (4) The ethoxylated modified hydrophobic compound C5 obtained from the reaction is mixed with sodium diethyldithiocarbamate (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%) and water in a mass ratio of 20:15:5:3:58 and stirred evenly to obtain the corrosion inhibitor.

[0053] Example 6

[0054] A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor includes the following steps:

[0055] (1) 76.2g of N-oleo-dipropylenetriamine and 29.4g of tetradecenyl succinic acid were mixed, heated to 60°C and stirred. The mixture was reacted at 160°C for 5 hours to obtain the multi-hydrophobic compound A6.

[0056] (2) The multi-hydrophobic compound A6 obtained in step (1) was mixed with 28.8 g of allyl sulfonic acid and reacted at 140 °C for 5 h to obtain polymer B6.

[0057] (3) Add 0.35g of potassium hydroxide catalyst to polymer B6, heat to 150℃, remove oxygen by vacuum, slowly introduce 88g of ethylene oxide, react for 6h to obtain ethoxylated modified hydrophobic compound C6.

[0058] (4) The ethoxylated modified hydrophobic compound C6 obtained from the reaction is mixed with sodium diethyldithiocarbamate (99%), sodium mercaptoacetate solution (20%), mercaptoethanol (99%) and water in a mass ratio of 20:10:5:3:62 and stirred evenly to obtain the corrosion inhibitor.

[0059] Comparative Example 1

[0060] Commercially available formula: 20% diethylenetriamine imidazoline oleate + 5% thiourea + 3% acetic acid + 72% tap water.

[0061] Comparative Example 2

[0062] Commercially available formula: 20% triethylenetetramine imidazoline oleate + 5% thiourea + 3% acetic acid + 72% tap water.

[0063] Performance testing

[0064] The corrosion inhibition performance of Examples 1-6 above was compared with that of Comparative Examples 1-2.

[0065] Experimental medium: Simulated water quality from an offshore oil field (mineralization 50000 mg / L)

[0066] Experimental temperature: 68℃

[0067] Drug concentration: 30 mg / L

[0068] Hanger material: 20# carbon steel

[0069] Evaluation standard: SY / T 5273 "Performance Evaluation Method for Corrosion Inhibitors in Oilfield Produced Water"

[0070] Evaluation method:

[0071] Soak the steel test piece in anhydrous ethanol for about 5 minutes, remove the test piece, wipe it dry with filter paper, dry it with cold air, wrap it up, put it in a desiccator to dry for 30 minutes, and weigh it (accurate to 0.0001g).

[0072] Pour 2L of water sample into the autoclave and add the corrosion inhibitor of the specified concentration. Fix three test pieces in the PTFE tank of the autoclave's plate-hanging system. Assemble the autoclave, sequentially purge with nitrogen, then evacuate to remove oxygen. Inject carbon dioxide and nitrogen at the specified experimental pressure into the autoclave. Control the temperature to the experimental temperature, set the rotation speed to 451 rpm, and dynamically hang the plates for 72 hours. After heating to the specified temperature and running for 72 hours, observe the water color and the appearance of the steel plates (gloss, film characteristics, local spots). After treatment with standard pickling solution and anhydrous ethanol, weigh, record, and calculate the results. The results are shown in Table 1.

[0073] Table 1. Performance Evaluation of Corrosion Inhibitors in Simulated Water Samples from an Offshore Oilfield

[0074]

[0075]

[0076] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor, characterized in that: Includes the following steps: S1. Mix alkylamine and long-chain alkenyl acid in a molar ratio of 1:(1-3) and stir. React at 140℃-160℃ for 4-5 hours to obtain polyhydrophobic compound A. S2. Mix the double bond sulfonate compound and the hydrophobic compound A obtained in step S1 at a molar ratio of 1:(1-3) and react at 120℃-140℃ for 4-5 hours to obtain polymer B. S3. Add a catalyst to polymer B obtained in step S2, heat to 130℃-150℃, remove oxygen by vacuum, slowly introduce ethylene oxide, the molar ratio of ethylene oxide to polymer B is (10-20):1, react for 4-6 hours to obtain ethoxylated modified hydrophobic compound C. S4. The ethoxylated modified hydrophobic compound C obtained in step S3 is mixed with DTC salt, sodium mercaptoacetate solution, mercaptoethanol, and water in a mass ratio of 10-20:5-20:1-5:1-3:52-83 and stirred evenly to obtain a corrosion inhibitor; wherein the concentration of sodium mercaptoacetate solution is 20%, the concentration of DTC salt is 99%, and the concentration of mercaptoethanol is 99%.

2. The preparation method of the ethoxylated modified multi-hydrophobic corrosion inhibitor according to claim 1, characterized in that: In step S1, the alkylamine is selected from one of octadeceneamine, N-oleo-1,3-propanediamine, and N-oleo-dipropanetriamine.

3. The preparation method of the ethoxylated modified multi-hydrophobic corrosion inhibitor according to claim 1, characterized in that: In step S1, the long-chain alkenyl acid is selected as tetradecenyl succinic acid.

4. The preparation method of the ethoxylated modified multi-hydrophobic corrosion inhibitor according to claim 1, characterized in that: In step S2, the double bond sulfonate compound is selected from sodium 2-acrylamido-2-methylpropanesulfonate or sodium allyl sulfonate.

5. The preparation method of the ethoxylated modified multi-hydrophobic corrosion inhibitor according to claim 1, characterized in that: In step S3, the catalyst is selected from potassium hydroxide or sodium formate.

6. The method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor according to claim 1, characterized in that: In step S3, the amount of catalyst added is 0.2%-0.5% of the mass of polymer B.

7. The method for preparing an ethoxylated modified multi-hydrophobic corrosion inhibitor according to claim 1, characterized in that: In step S4, the DTC salt is sodium diethyldithiocarbamate.

8. An ethoxylated modified hydrophobic corrosion inhibitor prepared by any one of the preparation methods described in claims 1-7.

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