Ionic liquid corrosion inhibitor for low-temperature part of tower top of oil refinery as well as preparation method and application of ionic liquid corrosion inhibitor

Abstract

The invention provides an ionic liquid corrosion inhibitor for a low-temperature part of a tower top of an oil refinery and a preparation method and application of the ionic liquid corrosion inhibitor. The preparation method of the ionic liquid corrosion inhibitor comprises the following steps: adding dichloromethane, triethylamine and benzyl alcohol into a reaction container, stirring and dispersing, adding a sulfonyl chloride compound, and stirring to obtain a reaction solution; stirring and reacting at room temperature, carrying out vacuum distillation to remove dichloromethane, and washing and drying a residual product to obtain solid powder; and adding the solid powder into acetonitrile, stirring and dissolving, then adding an imidazole compound, stirring and reacting at 60-80 DEG C, then carrying out vacuum distillation to remove acetonitrile, dispersing residues by using ethyl acetate, carrying out water extraction, carrying out water-phase distillation and drying to obtain the ionic liquid corrosion inhibitor for the low-temperature part at the tower top of the oil refinery. The corrosion inhibitor disclosed by the invention has excellent water solubility and stability, and the use safety of a product can be remarkably improved; meanwhile, the additive amount is small, the corrosion inhibition effect is remarkable, and the industrial application prospect is wide.

Description

TECHNICAL FIELD

[0001] The present application relates to the ion liquid corrosion inhibitor technology, especially to an ion liquid corrosion inhibitor for the low temperature part of the overhead of a refinery, a preparation method and application thereof. BACKGROUND

[0002] The processing of crude oil is a continuous and highly automated industrial production process. With the increase of crude oil processing capacity, the properties of crude oil are also developing in the direction of inferiority. Processing high-sulfur, high-chlorine and high-acid crude oil has become the norm in the industry. It is extremely important to ensure the safe and stable operation of crude oil processing equipment.

[0003] In recent years, with the normalization of high-sulfur and high-salt crude oil refining, a series of serious corrosion problems exist in the process of crude oil processing. Hydrogen sulfide and hydrogen chloride corrosion of steel is common in various aspects of oil processing and refining, especially in the low temperature part (less than 120℃) of the condensing and cooling system of the overhead of the oil processing device. It is a very serious corrosion and damage factor. Sulfur, chlorine and other elements in crude oil can form acid substances in the processing process, which are discharged from the overhead of the processing device, such as the atmospheric and vacuum distillation unit, catalytic cracking, hydrofining, hydrocracking, delayed coking, etc. These acid substances cause serious corrosion and damage to processing equipment and pipelines. Pipeline leaks caused by corrosion force the device to be shut down for repair or partially shut down for processing at reduced capacity, causing huge economic losses to the refinery, and easily leading to catastrophic consequences such as safety accidents and environmental pollution. Therefore, adding corrosion inhibitor technology is the most commonly used corrosion protection method in refineries, which is both economical and effective and does not affect normal production. A small amount of addition can reduce the corrosion rate of metal. Oil-soluble imidazoline corrosion inhibitors have been widely used due to their excellent performance and no adverse effects on oil quality. However, the use of oil as a solvent and the separation of neutralizing agents make the process more complex and less safe.

[0004] Therefore, it is a very meaningful work to develop and research new green, environmentally friendly and efficient water-soluble corrosion inhibitors. Water-soluble imidazoline corrosion inhibitors have low cost, use water as solvent, are safe during transportation and use, can be compounded with neutralizing agents, and are easy to add. The main component of the existing neutralizing corrosion inhibitor on the market is water-soluble imidazoline, which is modified by quaternization or epoxidation based on oil-soluble imidazoline to increase water solubility. However, the performance of water-soluble products is unstable, and the corrosion inhibition rate for hydrogen sulfide corrosion caused by high-sulfur crude oil is low. It is urgent to develop a high-efficiency corrosion inhibitor for low-temperature parts of refineries that has good corrosion protection effect for high-sulfur crude oil. SUMMARY

[0005] The present application aims at the above-mentioned problems, and provides an ionic liquid corrosion inhibitor for a low-temperature part of a refinery tower, which has excellent water solubility and stability, can significantly improve the use safety of products, has a small addition amount, has a significant corrosion inhibition effect on high-sulfur crude oil, and has a wide industrial application prospect.

[0006] It should be noted that, in the present application, unless otherwise specified, the specific meaning of "including" involved in the composition limitation and description includes both the open "including", "containing" and the like and the closed "consisting of", "consisting" and the like.

[0007] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows: a preparation method of an ionic liquid corrosion inhibitor for a low-temperature part of a refinery tower, comprising the following steps:

[0008] (1) dichloromethane, triethylamine and benzyl alcohol are added to a reaction container, stirred and dispersed, and then a sulfonyl chloride compound is added, stirred and reacted at room temperature for 3-6 hours, after the reaction is completed, dichloromethane is removed by vacuum distillation, and the remaining product is washed with water, dried to obtain a solid powder; the amount ratio of the dichloromethane, triethylamine, benzyl alcohol and sulfonyl chloride compound is 0.5-1:0.1-0.3:0.1-0.3:0.1-0.3 (mol: mol: mol: mol);

[0009] (2) the solid powder obtained in step (1) is added to acetonitrile, stirred and dissolved, and then an imidazole compound is added, stirred and reacted at 40-60℃ for 12-24 hours, after the reaction is completed, acetonitrile is removed by vacuum distillation, and the remaining product is dispersed with ethyl acetate, extracted with water, distilled in water phase and dried to obtain the ionic liquid corrosion inhibitor for the low-temperature part of the refinery tower; the amount ratio of the acetonitrile, solid powder and imidazole compound is 1-2:0.1-0.3:0.1-0.3 (mol: mol: mol).

[0010] Further, the sulfonyl chloride compound in step (1) is selected from one or more of propyl sulfonyl chloride, ethyl sulfonyl chloride, butyl sulfonyl chloride, benzyl sulfonyl chloride and phenyl sulfonyl chloride.

[0011] Further, in step (1), the amount ratio of the dichloromethane, triethylamine, benzyl alcohol and sulfonyl chloride compound is 1:0.1:0.13:0.1 mol: mol: mol: mol.

[0012] Further, in step (1), the stirring and reaction at room temperature is performed for 3-4 hours.

[0013] Further, the water washing in step (1) is performed 2-3 times.

[0014] Further, the drying condition in step (1) is vacuum drying at 60-80℃ for 12-24 hours.

[0015] Further, the imidazole compound (N-ethyl imidazole) in step (2) is 1-(3-aminopropyl)imidazole and / or 1-methyl imidazole.

[0016] Further, in step (2), the ratio of acetonitrile, solid powder and imidazole compound is 1:0.1:0.1 (mol:mol:mol).

[0017] Further, the reaction temperature in step (2) is 50-60℃, and the reaction time is 18-24h.

[0018] Further, the water extraction times in step (2) is 2-3 times.

[0019] Further, the drying condition in step (2) is vacuum drying at 60-80℃ for 12-24 hours.

[0020] Taking the propyl sulfonyl chloride as the sulfonyl chloride compound and N-ethyl imidazole as the imidazole compound as an example, the typical molecular structure of the prepared ionic liquid corrosion inhibitor is as follows:

[0021]

[0022] Another object of the present application also discloses an ionic liquid corrosion inhibitor for the low-temperature part of the overhead of a refinery tower, which is prepared by the above preparation method.

[0023] Further, the structure formula of the ionic liquid corrosion inhibitor for the low-temperature part of the overhead of the refinery tower is as follows:

[0024]

[0025] Another object of the present application also discloses the application of the ionic liquid corrosion inhibitor for the low-temperature part of the overhead of the refinery tower in the corrosion protection field of the low-temperature part of the overhead of the refinery tower.

[0026] Further, the ionic liquid corrosion inhibitor for the low-temperature part of the overhead of the refinery tower is especially suitable for the corrosion protection of the low-temperature part of the overhead pipeline of the crude distillation tower, the atmospheric tower and the vacuum tower of the crude distillation unit of the refinery.

[0027] Further, the temperature of the low-temperature part is less than or equal to 120℃.

[0028] Further, the addition amount of the ionic liquid corrosion inhibitor for the low-temperature part of the overhead of the refinery tower in the system is 1-2ppm.

[0029] The present application is an ionic liquid corrosion inhibitor for low-temperature parts of oil refinery overhead, its preparation method and application, which has the following advantages compared with the prior art:

[0030] 1) The ionic liquid corrosion inhibitor for low-temperature parts of oil refinery overhead is water-soluble, does not use organic solvents, reduces environmental pollution, and meets the green and environmentally friendly industrial development trend. The ionic liquid corrosion inhibitor has good chemical stability and is not prone to decomposition or failure during long-term storage and use, ensuring the durability of the corrosion inhibition effect.

[0031] The ionic liquid corrosion inhibitor for low-temperature parts of oil refinery overhead is particularly suitable for hydrogen sulfide corrosion caused by high-sulfur crude oil and has excellent corrosion prevention effect.

[0032] 2) The ionic liquid corrosion inhibitor for low-temperature parts of oil refinery overhead has a small addition amount and can achieve a corrosion inhibition rate of more than 92% at a low concentration (1-2 mg / L), which is significantly better than traditional oil-soluble and water-soluble corrosion inhibitors, and can effectively inhibit corrosion problems caused by hydrogen sulfide and hydrogen chloride at low-temperature parts of oil refinery overhead.

[0033] 3) The preparation method of the present application successfully synthesizes an ionic liquid corrosion inhibitor with a quaternary ammonium salt structure through substitution reaction and quaternization reaction. The reaction conditions are mild, the steps are clear, the product purity is high, and it is suitable for industrial production.

[0034] 4) The product separation and purification can be completed through conventional operations such as vacuum distillation, water washing, and drying, and the process steps are simple and easy to operate.

[0035] 5) The corrosion inhibitor is suitable for corrosion protection of low-temperature parts (≤120℃) of oil refinery overhead, can meet the needs of high-sulfur and high-chlorine crude oil processing, and has broad market promotion potential and economic benefits.

[0036] The ionic liquid corrosion inhibitor for low-temperature parts of oil refinery overhead has significant advantages in performance, preparation process, and environmental protection, and has good application prospects and large-scale promotion potential in the field of corrosion protection of low-temperature parts of oil refinery overhead. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The infrared spectrum of the ionic liquid corrosion inhibitor for low-temperature parts of oil refinery overhead of Example 1. DETAILED DESCRIPTION

[0038] Hereinafter, the present application will be further described in conjunction with examples. The description of the technical features described below is based on representative embodiments, specific examples of the present application, but the present application is not limited to these embodiments, specific examples. It should be noted that:

[0039] The units used in the present specification are international standard units unless otherwise specified, and the numerical values, numerical ranges appearing in the present application should be understood to include the inevitable systematic errors in industrial production.

[0040] In the present specification, the numerical range indicated using "numerical value A to numerical value B" means a range including the end point numerical values A and B.

[0041] In the present specification, the numerical range indicated using "above" or "below" means a numerical range including the present number.

[0042] In the present specification, the meaning indicated using "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0043] In the present specification, "optional" or "optionally" indicates the use or non-use of certain substances, components, execution steps, applied conditions, and the like.

[0044] In the present specification, when "room temperature" is used, the temperature can be 15-25°C.

[0045] In the present specification, the reagents or instruments used are all conventional products that can be obtained by purchase unless otherwise specified.

[0046] Example 1

[0047] The present embodiment discloses an ionic liquid corrosion inhibitor for the low-temperature part of the overhead of a refinery column, and the preparation method is as follows:

[0048] First step, 1 mol L dichloromethane, 0.1 mol triethylamine and 0.1 mol benzyl alcohol are put into a three-necked flask. After stirring and dispersing, 0.1 of propylsulfonyl chloride is added, and stirring is carried out at room temperature for 3 hours. After the reaction is completed, dichloromethane is removed by vacuum distillation, the remaining product is washed with distilled water three times, and vacuum drying is carried out at 80°C for 24 hours to obtain a solid powder.

[0049] Second step, 1 mol of acetonitrile is added to a three-necked flask, and the solid powder obtained in the previous step is added to the three-necked flask and stirred to dissolve. Then, 0.1 mol of 1-(3-aminopropyl)imidazole is added, and stirring is carried out at 60°C for 24 hours. After the reaction is completed, acetonitrile is removed by vacuum distillation. The remaining substance is dispersed in ethyl acetate after vacuum distillation, extracted with distilled water three times and entered into the water phase. The water phase is distilled again, distilled water is removed, and vacuum drying is carried out at 80°C for 24 hours to obtain a solid powder, which is an ionic liquid corrosion inhibitor for the low-temperature part of the overhead of a refinery column. The typical molecular structure of the prepared ionic liquid corrosion inhibitor is as follows:

[0050]

[0051] First step reaction principle:

[0052] Reactants: Benzyl alcohol (C6H5CH2OH) and propane sulfonyl chloride (CH3CH2CH2SO2Cl).

[0053] Product: Benzyl propane sulfonate (C6H5CH2OSO2CH2CH2CH3).

[0054] Reaction type: Substitution reaction, in which the hydroxyl group (-OH) of benzyl alcohol is replaced by the chlorine atom (-Cl) of propane sulfonyl chloride to form a sulfonate ester.

[0055] Second step reaction principle:

[0056] Reactants: Benzyl propane sulfonate (C6H5CH2OSO2CH2CH2CH3) and 1-(3-aminopropyl)imidazole (C3H4N2CH2CH2NH2).

[0057] Product: Compound with quaternary ammonium salt structure (C6H5CH2OSO2CH2CH2N + C3H4N2CH2CH2NH2).

[0058] Reaction type: Quaternization reaction, in which the amino group (-NH2) of 1-(3-aminopropyl)imidazole reacts with the sulfonyl group (-SO2) of the sulfonate ester to form a quaternary ammonium salt.

[0059] The infrared spectrum of the ion liquid corrosion inhibitor prepared in this example for the low temperature part of the refinery overhead is shown in Figure Figure 1 As can be seen from the figure, the amino vibration peak is at 3400-3500, the benzene ring C-H bond absorption peak is at 2962 cm -1 , the imidazoline ring C=N vibration peak is at 1600 cm -1 , the benzene ring skeleton absorption vibration peak is at 1500 cm -1 , and the sulfonic acid group symmetric and asymmetric vibration absorption peaks are at 1034 cm -1 , 1157 cm -1 . It can be seen that the product structure completely corresponds to the infrared spectrum.

[0060] The finished ion liquid corrosion inhibitor for the low temperature part of the refinery overhead prepared in this example was evaluated for release rate according to the China Petroleum Chemical Group Company Enterprise Standard Q / SHCG 109-2017. The evaluation corrosion medium was 1000 mg / L hydrochloric acid solution, the static hanging piece method was used, and the hanging piece material was A20 steel test piece. The corrosion inhibition rates of ion liquid corrosion inhibitors of different concentrations are shown in Table 1:

[0061] Table 1 Ion liquid corrosion inhibitor corrosion inhibition rate test results

[0062]

[0063] The 2%, 5%, 10%, 20% different concentration of ionic liquid corrosion inhibitor samples are added to the neutralizer and placed for 7 days, and the product has good stability and no turbidity and stratification phenomenon.

[0064] Example 2

[0065] The embodiment discloses an ionic liquid corrosion inhibitor for a low-temperature part of a refinery tower, and a preparation method thereof is as follows:

[0066] In the first step, 1 mol of dichloromethane, 0.1 mol of triethylamine and 0.1 mol of benzyl alcohol are put into a three-necked flask. After stirring and dispersing, 0.1 mol of propyl sulfonyl chloride is added, and stirring is performed at room temperature for 3 hours. After the reaction is completed, dichloromethane is removed by vacuum distillation, the remaining product is washed with distilled water three times, and vacuum drying is performed at 80 DEG C for 24 hours to obtain a solid powder.

[0067] In the second step, 1 mol of acetonitrile is added to the three-necked flask, the solid powder obtained in the above step is added to the three-necked flask and stirred and dissolved, then 0.1 mol of 1-methylimidazole is added, and stirring is performed at 60 DEG C for 24 hours. After the reaction is completed, acetonitrile is removed by vacuum distillation. The remaining substance is dispersed in ethyl acetate after vacuum distillation, extracted with distilled water three times and introduced into the water phase. The water phase is distilled again, distilled water is removed, and vacuum drying is performed at 80 DEG C for 24 hours to obtain a solid powder, which is an ionic liquid corrosion inhibitor for a low-temperature part of a refinery tower. The typical molecular structure of the prepared ionic liquid corrosion inhibitor is as follows:

[0068]

[0069] Example 3

[0070] The embodiment discloses an ionic liquid corrosion inhibitor for a low-temperature part of a refinery tower, and a preparation method thereof is as follows:

[0071] In the first step, 1 mol of dichloromethane, 0.1 mol of triethylamine and 0.1 mol of benzyl alcohol are put into a three-necked flask. After stirring and dispersing, 0.1 mol of propyl sulfonyl chloride is added, and stirring is performed at room temperature for 3 hours. After the reaction is completed, dichloromethane is removed by vacuum distillation, the remaining product is washed with distilled water three times, and vacuum drying is performed at 80 DEG C for 24 hours to obtain a solid powder.

[0072] Second step, 1 mol of acetonitrile is added into a three-necked flask, the solid powder obtained in the first step is added into the three-necked flask and stirred to dissolve, then 0.1 mol of 1-(3-aminopropyl)imidazole is added, and the mixture is stirred at 60°C for 24 hours. After the reaction is completed, acetonitrile is removed by vacuum distillation. The residue is dispersed in ethyl acetate, extracted with distilled water three times, and the water phase is obtained. The water phase is distilled again, distilled water is removed, and the mixture is dried at 80°C under vacuum for 24 hours to obtain a solid powder, which is an ionic liquid corrosion inhibitor for the low-temperature part of the refinery overhead.

[0073]

[0074] Example 4

[0075] This example discloses an ionic liquid corrosion inhibitor for the low-temperature part of the refinery overhead, and the preparation method is as follows:

[0076] First step, 1 mol of dichloromethane, 0.13 mol of triethylamine, and 0.1 mol of benzyl alcohol are added into a three-necked flask. After stirring and dispersing, 0.1 mol of ethylsulfonyl chloride is added, and the mixture is stirred at room temperature for 3 hours. After the reaction is completed, dichloromethane is removed by vacuum distillation, the remaining product is washed with distilled water three times, and the mixture is dried at 80°C under vacuum for 24 hours to obtain a solid powder.

[0077] Second step, 1 mol of acetonitrile is added into a three-necked flask, the solid powder obtained in the first step is added into the three-necked flask and stirred to dissolve, then 0.1 mol of 1-methylimidazole is added, and the mixture is stirred at 60°C for 24 hours. After the reaction is completed, acetonitrile is removed by vacuum distillation. The residue is dispersed in ethyl acetate, extracted with distilled water three times, and the water phase is obtained. The water phase is distilled again, distilled water is removed, and the mixture is dried at 80°C under vacuum for 24 hours to obtain a solid powder, which is an ionic liquid corrosion inhibitor for the low-temperature part of the refinery overhead. The typical molecular structure of the prepared ionic liquid corrosion inhibitor is as follows:

[0078]

[0079] Finally, it should be noted that the above examples are used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A process for the preparation of an ionic liquid corrosion inhibitor for use in the low temperature overhead section of a refinery column, characterized by, The method comprises the following steps: (1) adding dichloromethane, triethylamine and benzyl alcohol into a reaction container, stirring and dispersing, then adding a sulfonyl chloride compound, stirring at room temperature for 3-6 hours, removing dichloromethane by vacuum distillation after the reaction is completed, and obtaining a solid powder by washing with water and drying; the amount ratio of the dichloromethane, triethylamine, benzyl alcohol and sulfonyl chloride compound is 0.5-1:0.1-0.3:0.1-0.3:0.1-0.3 (mol: mol: mol: mol); (2) adding the solid powder obtained in step (1) into acetonitrile to stir and dissolve, then adding an imidazole compound, stirring at 40-60℃ for 12-24 hours, removing acetonitrile by vacuum distillation after the reaction is completed, and obtaining the ionic liquid corrosion inhibitor for the low-temperature part of a refinery overhead by dispersing with ethyl acetate, extracting with water, distilling the water phase and drying; the amount ratio of the acetonitrile, solid powder and imidazole compound is 1-2:0.1-0.3:0.1-0.3 (mol: mol: mol).

2. The process for the preparation of ionic liquid corrosion inhibitor for low temperature overhead section of refinery columns as claimed in claim 1 wherein, The sulfonyl chloride compound in step (1) is one or more selected from propylsulfonyl chloride, ethylsulfonyl chloride, butylsulfonyl chloride, benzylsulfonyl chloride and phenylsulfonyl chloride.

3. The process for the preparation of ionic liquid corrosion inhibitor for low temperature overhead section of refinery columns as claimed in claim 1 wherein, The number of water washing in step (1) is 2-3 times.

4. The process for the preparation of ionic liquid corrosion inhibitor for low temperature overhead section of refinery columns as claimed in claim 1 wherein, The drying condition in step (1) is vacuum drying at 60-80℃ for 12-24 hours.

5. The process for the preparation of ionic liquid corrosion inhibitor for low temperature overhead section of refinery columns as claimed in claim 1 wherein, The imidazole compound in step (2) is 1-(3-aminopropyl)imidazole and / or 1-methylimidazole.

6. The process for the preparation of ionic liquid corrosion inhibitor for low temperature overhead section of refinery columns as claimed in claim 1 wherein, The number of water extraction in step (2) is 2-3 times.

7. The process for the preparation of ionic liquid corrosion inhibitor for low temperature overhead section of refinery columns as claimed in claim 1 wherein, The drying condition in step (2) is vacuum drying at 60-80℃ for 12-24 hours.

8. An ionic liquid corrosion inhibitor for use in the overhead cryogenic section of a refinery column, characterized in that, Prepared by the preparation method in any one of claims 1-7.

9. Use of the ionic liquid corrosion inhibitor for the low-temperature part of a refinery overhead in claim 8 in the field of corrosion protection for the low-temperature part of a refinery overhead.

10. Use according to claim 9, characterized in that, The temperature of the low-temperature part is less than or equal to 120℃.

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