A pour point depressant for pipeline crude oil and a preparation method and application thereof

Abstract

The application discloses a pipe transportation crude oil pour point depressant, a preparation method and application thereof, and belongs to the technical field of oil field chemicals. The pour point depressant comprises a first component, a second component, a third component and a fourth component; the first component is a terpolymer of ethylene, acrylate and vinyl acetate; the second component is an amination product of a quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate; the third component is a polyether compound of ethylene oxide, propylene oxide and glycol; and the fourth component is one or more of polymethylsilsesquioxane, sorbitol anhydride fatty acid ester, polyisobutylene succinic anhydride derivative and ethylene glycol monobutyl ether. The limitations of the single-component pour point depressant are solved, the application range is wider, the pour point of crude oil is significantly reduced, the low-temperature fluidity of the crude oil is effectively improved, and the high pour point crude oil is convenient to exploit and transport.

Description

Technical Field

[0001] This application relates to a pipeline crude oil pour point depressant, its preparation method, and its application, belonging to the field of oilfield chemical technology. Background Technology

[0002] Crude oil is an important petroleum resource, containing large amounts of easily crystallizing substances such as gums, asphaltenes, and paraffin wax. Newly extracted crude oil has increasingly higher pour point, wax content, and viscosity. During crude oil transportation, when the transportation temperature drops to the crude oil's wax precipitation point, it begins to crystallize. If the temperature drops further, the amount of crystallized crude oil increases, eventually causing it to lose its fluidity and solidify on the pipe wall. This poses significant challenges to crude oil extraction and transportation.

[0003] Pour point depressants, as commonly used chemical additives, are widely used in crude oil extraction and transportation to effectively improve crude oil fluidity and reduce transportation costs and risks. Commonly used crude oil pour point depressants mainly include ethylene-vinyl acetate copolymers, styrene-maleic anhydride copolymers, and acrylate polymers. For example, Chinese invention patent CN105567353B discloses a modified ethylene-vinyl acetate copolymer pour point depressant: a surface-polymerized ethylene-vinyl acetate copolymer is then mixed with polycaprolactone to obtain this product. While these pour point depressants have proven effective in some regions, the differences in crude oil composition across regions lead to selectivity in pour point depressant application. Single-type pour point depressants have poor applicability and are difficult to meet pour point requirements, thus limiting the use of existing crude oil pour point depressants and hindering large-scale application. Summary of the Invention

[0004] The purpose of this invention is to provide a pipeline crude oil pour point depressant, its preparation method, and its application, thereby solving the limitations of single-component pour point depressants, expanding their application range, significantly reducing the pour point of crude oil, effectively improving the low-temperature fluidity of crude oil, and making high-pour-point crude oil easier to mine and transport.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] According to one aspect of this application, a pipeline crude oil pour point depressant is provided, comprising a first component, a second component, a third component, and a fourth component;

[0007] The first component is a terpolymer of ethylene, acrylate and vinyl acetate, and the molecular weight of the first component is 10,000-15,000.

[0008] The second component is an amination product of a quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and methacrylate, and the molecular weight of the second component is 8000-12000.

[0009] The third component is a polyether compound of ethylene oxide, propylene oxide and Guerbert alcohol, and the molecular weight of the third component is 3000-8000.

[0010] The fourth component is one or more of polymethylsilsesquioxane, sorbitan fatty acid ester, polyisobutylene succinic anhydride derivative, and ethylene glycol monobutyl ether.

[0011] Optionally, the mass ratio of the first component, the second component, the third component and the fourth component is (10-15):(35-55):(5-10):(1-5).

[0012] Optionally, the mass ratio of ethylene, acrylate and vinyl acetate in the first component is (50-65):(5-8):(15-45).

[0013] Optionally, the mass ratio of maleic anhydride, vinylimidazole, acrylamide and methacrylate in the second component is (10-15):(2-3):(1-2):(30-50).

[0014] Optionally, the mass ratio of ethylene oxide, propylene oxide and gerbert alcohol in the third component is (20-30):(40-50):(1-10).

[0015] According to another aspect of this application, a method for preparing a pipeline crude oil pour point depressant is provided, the method being used to prepare any of the above-described pipeline crude oil pour point depressants, the method comprising the following steps:

[0016] (1) Add acrylate, vinyl acetate, initiator and light aromatic solvent to a high-pressure reactor, heat to 80-150°C, and introduce ethylene gas to carry out the reaction. The mass ratio of ethylene, acrylate and vinyl acetate is (50-65):(5-8):(15-45). Then, use ethanol to perform hot washing at 50-70°C to remove unreacted monomers. Then, vacuum at 150-170°C to remove the solvent and obtain the first component.

[0017] (2) Maleic anhydride, vinyl imidazole, acrylamide and methacrylate in a mass ratio of (10-15):(2-3):(1-2):(30-50) are dissolved in a light aromatic solvent, and azobisisobutyronitrile is added. Under nitrogen protection, a polymerization reaction is carried out at 60-90°C to obtain a quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate. Then, the quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate is mixed with amine and subjected to an amination reaction at 100-160°C. Then, the unreacted monomers are removed by hot washing with a methanol and water mixture in a weight ratio of 1:1 at 60-80°C. Then, the solvent is removed by vacuuming at 140-160°C to obtain the second component.

[0018] (3) Add Gelbert alcohol and catalyst to a high-pressure reactor, heat to 110-130°C, and introduce propylene oxide and ethylene oxide to react. The mass ratio of ethylene oxide, propylene oxide and Gelbert alcohol is (20-30):(40-50):(1-10). Then, vacuum at 120-150°C to remove unreacted monomers and obtain the third component.

[0019] (4) Dissolve the first component, the second component, the third component and the fourth component in a heavy aromatic solvent at a mass ratio of (10-15):(35-55):(5-10):(1-5) to obtain the pipeline crude oil pour point depressant.

[0020] Optionally, the acrylate is one or more selected from dodecyl acrylate, tetradecyl acrylate, hexadecyl acrylate, and octadecyl acrylate;

[0021] The methacrylate is one or more selected from dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, and octadecyl methacrylate;

[0022] The amine is one or more selected from dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine;

[0023] The Gerbert alcohol is one or more of Gerbert dodecyl alcohol, Gerbert tetradecyl alcohol, Gerbert hexadecyl alcohol, and Gerbert octadecyl alcohol;

[0024] The initiator is selected from at least one of benzoyl peroxide, lauroyl peroxide, benzoyl tert-butyl peroxide, methyl ethyl ketone peroxide, and di-tert-butyl peroxide;

[0025] The light aromatic solvent is benzene, toluene, or xylene;

[0026] The catalyst is sodium hydroxide and / or potassium hydroxide;

[0027] The heavy aromatic solvent is No. 150 solvent oil.

[0028] Optionally, the amount of the initiator added is 0.1–0.5 wt%.

[0029] The amount of azobisisobutyronitrile added is 0.1–0.5 wt%;

[0030] The molar ratio of the amine to maleic anhydride is (1-2):1;

[0031] The catalyst is added in an amount of 0.3 to 0.6 wt%.

[0032] According to another aspect of this application, the application of any of the above-described pipeline crude oil pour point depressants in lowering the pour point of crude oil is provided, wherein the dosage of the pipeline crude oil pour point depressant is 1700-1900 ppm.

[0033] The beneficial effects of this application include, but are not limited to:

[0034] 1. The pipeline crude oil pour point depressant of this application has a first component, a second component, a third component, and a fourth component that work synergistically to solve the limitations of single-component pour point depressants. A small amount of addition can greatly reduce the pour point of crude oil and improve its low-temperature fluidity, making it easier to extract and transport.

[0035] 2. The pipeline crude oil pour point depressant of this application utilizes acrylate to appropriately modify the ethylene-vinyl acetate copolymer. The first component has a uniformly distributed polar portion, and its long-chain structure can interact with wax crystals in high-pour-point crude oil. Secondly, the acrylate structure has strong polarity, which can better adjust the wax crystal structure and reduce the pour point of crude oil.

[0036] 3. The pipeline crude oil pour point depressant of this application is an amination product of a quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and methacrylate. It has a comb-like structure, and the lengths of its main chain and branched carbon chains are similar to the lengths of paraffin carbon chains. This can change the crystallization state of paraffin in crude oil, making it less likely to form a spatial network structure, and significantly reducing the pour point of crude oil.

[0037] 4. The pipeline crude oil pour point depressant of this application contains polar ether bonds in the polyether compounds of ethylene oxide, propylene oxide and Guerbert alcohol, which can be adsorbed on the surface of wax crystals, preventing wax molecules from further agglomerating to form large particles of crystals, and keeping the wax crystals in a fine and dispersed state; its molecules can insert into the lattice of wax crystals, interfere with the regular arrangement of wax crystals, destroy the ordered crystal structure, reduce the interaction and entanglement between wax crystals, thereby lowering the pour point of crude oil.

[0038] 5. The pipeline crude oil pour point depressant of this application, including polymethylsilsesquioxane, sorbitan fatty acid ester, polyisobutylene succinic anhydride derivative, and ethylene glycol monobutyl ether, can increase the interaction between the pour point depressant and crude oil, thereby improving the pour point depressant effect. Attached Figure Description

[0039] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0040] Figure 1 This is the infrared spectrum of the first component in the pipeline crude oil pour point depressant of Example 3 of this application.

[0041] Figure 2 This is the infrared spectrum of the second component in the pipeline crude oil pour point depressant of Example 3 of this application.

[0042] Figure 3 This is the infrared spectrum of the third component in the pipeline crude oil pour point depressant of Example 3 of this application. Detailed Implementation

[0043] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0044] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0045] 1. A pipeline crude oil pour point depressant and its preparation method

[0046] 1.1 The present invention provides a pipeline crude oil pour point depressant, comprising a first component, a second component, a third component, and a fourth component;

[0047] The first component is a terpolymer of ethylene, acrylate and vinyl acetate, with a molecular weight of 10,000-15,000.

[0048] The second component is an amination product of a quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate, with a molecular weight of 8000-12000.

[0049] The third component is a polyether compound of ethylene oxide, propylene oxide and gerbert alcohol, with a molecular weight of 3000-8000.

[0050] The fourth component is one or more of polymethylsilsesquioxane, sorbitan fatty acid ester, polyisobutylene succinic anhydride derivative, and ethylene glycol monobutyl ether.

[0051] The mass ratio of the first component, the second component, the third component, and the fourth component is (10-15):(35-55):(5-10):(1-5); the mass ratio of ethylene, acrylate, and vinyl acetate in the first component is (50-65):(5-8):(15-45); the mass ratio of maleic anhydride, vinylimidazole, acrylamide, and methacrylate in the second component is (10-15):(2-3):(1-2):(30-50); and the mass ratio of ethylene oxide, propylene oxide, and Gelbert alcohol in the third component is (20-30):(40-50):(1-10).

[0052] 1.2 The preparation method of the above-mentioned pipeline crude oil pour point depressant includes the following steps:

[0053] (1) Add acrylate, vinyl acetate, initiator and light aromatic solvent to a high-pressure reactor, heat to 80-150°C, and introduce ethylene gas to carry out the reaction. The mass ratio of ethylene, acrylate and vinyl acetate is (50-65):(5-8):(15-45). Then, use ethanol to perform hot washing at 50-70°C to remove unreacted monomers. Then, vacuum at 150-170°C to remove the solvent and obtain the first component.

[0054] (2) Maleic anhydride, vinyl imidazole, acrylamide and methacrylate in a mass ratio of (10-15):(2-3):(1-2):(30-50) are dissolved in a light aromatic solvent. Azobisisobutyronitrile is added and polymerization is carried out at 60-90°C under nitrogen protection to obtain a quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate. Then, the quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate is mixed with an amine in a molar ratio of (1-2):1 and amination is carried out at 100-160°C. Then, the unreacted monomers are removed by hot washing with a methanol and water mixture in a weight ratio of 1:1 at 60-80°C. Then, the solvent is removed by vacuuming at 140-160°C to obtain the second component.

[0055] (3) Add Gelbert alcohol and catalyst to a high-pressure reactor, heat to 110-130°C, and introduce propylene oxide and ethylene oxide to react. The mass ratio of ethylene oxide, propylene oxide and Gelbert alcohol is (20-30):(40-50):(1-10). Then, vacuum at 120-150°C to remove unreacted monomers and obtain the third component.

[0056] (4) Dissolve the first component, the second component, the third component and the fourth component in a heavy aromatic solvent at a mass ratio of (10-15): (35-55): (5-10): (1-5) to obtain a pipeline crude oil pour point depressant.

[0057] The acrylate is one or more of dodecyl acrylate, tetradecyl acrylate, hexadecyl acrylate and octadecyl acrylate, with octadecyl acrylate being preferred;

[0058] The methacrylate is one or more of dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate and octadecyl methacrylate, with octadecyl methacrylate being preferred;

[0059] The amine is one or more of dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine, with octadecylamine being preferred;

[0060] Guerbert alcohol is one or more of Guerbert dodecyl alcohol, Guerbert tetradecyl alcohol, Guerbert hexadecyl alcohol and Guerbert octadecyl alcohol, with Guerbert hexadecyl alcohol being preferred;

[0061] The initiator is selected from at least one of benzoyl peroxide, lauroyl peroxide, benzoyl tert-butyl peroxide, methyl ethyl ketone peroxide, and di-tert-butyl peroxide, preferably benzoyl peroxide;

[0062] The light aromatic solvent is benzene, toluene, or xylene, with xylene being preferred;

[0063] The catalyst is sodium hydroxide and / or potassium hydroxide, preferably sodium hydroxide;

[0064] The heavy aromatic solvent is No. 150 solvent oil.

[0065] The amount of initiator added is 0.1–0.5 wt%, preferably 0.3 wt%;

[0066] The amount of azobisisobutyronitrile added is 0.1–0.5 wt%, preferably 0.3 wt%;

[0067] The molar ratio of amine to maleic anhydride is (1-2):1, preferably 1:1;

[0068] The amount of catalyst added is 0.3 to 0.6 wt%, preferably 0.4 wt%.

[0069] 2. The preparation method of the pipeline crude oil pour point depressant of the present invention can be described in detail as follows:

[0070] 2.1 A method for preparing a pipeline crude oil pour point depressant, comprising the following steps:

[0071] (1) Add octadecyl acrylate, vinyl acetate, 0.3 wt% benzoyl peroxide and xylene to a high-pressure reactor, heat to 80-150°C, and introduce ethylene gas to carry out the reaction. The mass ratio of ethylene, octadecyl acrylate and vinyl acetate is (50-65): (5-8): (15-45). Then, use ethanol to perform hot washing at 50-70°C to remove unreacted monomers. Then, vacuum at 150-170°C to remove the solvent and obtain the first component.

[0072] (2) Maleic anhydride, vinylimidazole, acrylamide and octadecyl methacrylate in a mass ratio of (10-15):(2-3):(1-2):(30-50) are dissolved in xylene, and 0.3wt% azobisisobutyronitrile is added. Under nitrogen protection, a polymerization reaction is carried out at 60-90℃ to obtain a quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and octadecyl methacrylate. Then, the quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and octadecyl methacrylate is mixed with octadecylamine, and the molar ratio of octadecylamine to maleic anhydride is 1:1. An amination reaction is carried out at 100-160℃. Then, the unreacted monomers are removed by hot washing with a methanol and water mixture in a weight ratio of 1:1 at 60-80℃. Then, the solvent is removed by vacuuming at 140-160℃ to obtain the second component.

[0073] (3) Add Guerbert hexadecyl alcohol and 0.4wt% sodium hydroxide to a high-pressure reactor, heat to 110-130°C, and introduce propylene oxide and ethylene oxide to react. The mass ratio of ethylene oxide, propylene oxide and Guerbert hexadecyl alcohol is (20-30):(40-50):(1-10). Then, vacuum at 120-150°C to remove unreacted monomers and obtain the third component.

[0074] (4) Dissolve the first component, the second component, the third component and the fourth component in No. 150 solvent oil at a mass ratio of (10-15): (35-55): (5-10): (1-5) to obtain the pipeline crude oil pour point depressant.

[0075] 3. The preparation method of the pipeline crude oil pour point depressant of the present invention can also be described in detail as follows:

[0076] 3.1 A method for preparing a pipeline crude oil pour point depressant, comprising the following steps:

[0077] (1) Add octadecyl acrylate, vinyl acetate, 0.3 wt% benzoyl peroxide and xylene to a high-pressure reactor, heat to 115°C, and introduce ethylene gas to carry out the reaction. The mass ratio of ethylene, octadecyl acrylate and vinyl acetate is (50-65): (5-8): (15-45). Then, use ethanol to perform hot washing at 60°C to remove unreacted monomers, and then vacuum at 160°C to remove the solvent to obtain the first component.

[0078] (2) Maleic anhydride, vinylimidazole, acrylamide and octadecyl methacrylate in a mass ratio of (10-15):(2-3):(1-2):(30-50) are dissolved in xylene, and 0.3 wt% azobisisobutyronitrile is added. Under nitrogen protection, a polymerization reaction is carried out at 75°C to obtain a quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and octadecyl methacrylate. Then, the quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and octadecyl methacrylate is mixed with octadecylamine, and the molar ratio of octadecylamine to maleic anhydride is 1:1. An amination reaction is carried out at 130°C. Then, the unreacted monomers are removed by hot washing with a methanol and water mixture in a weight ratio of 1:1 at 70°C. Then, the solvent is removed by vacuuming at 150°C to obtain the second component.

[0079] (3) Add Guerbert hexadecyl alcohol and 0.4wt% sodium hydroxide to a high-pressure reactor, heat to 120°C, and introduce propylene oxide and ethylene oxide to react. The mass ratio of ethylene oxide, propylene oxide and Guerbert hexadecyl alcohol is (20-30): (40-50): (1-10). Then, vacuum at 135°C to remove unreacted monomers and obtain the third component.

[0080] (4) Dissolve the first component, the second component, the third component and the fourth component in No. 150 solvent oil at a mass ratio of (10-15): (35-55): (5-10): (1-5) to obtain the pipeline crude oil pour point depressant.

[0081] The pour point depressants used in the following experimental examples were prepared according to the preparation method of the pipeline crude oil pour point depressant described in 3.1 above. The differences from the preparation conditions in 3.1 are listed in Tables 1 (Examples 1-8) and 2 (Comparative Examples 1-11). The following experimental examples can provide a reference for those skilled in the art to implement the invention or verify its effects. These examples do not limit the scope of the claims.

[0082] Table 1. Preparation conditions of Examples 1-8

[0083]

[0084] Table 2 Preparation conditions of Comparative Examples 1-11

[0085]

[0086] The pour point depressant effects of the crude oil from a certain block in Xinjiang were evaluated below, using the crude oil as a sample. The evaluation was conducted according to the method in GB / T 510-2018, and the results are shown in Table 3.

[0087] Table 3 Evaluation results of the pour point depressant effects of Examples 1-8 and Comparative Examples 1-11

[0088]

[0089] As can be seen from the data in Tables 1-3, the pour point depressants provided in the embodiments of the present invention (Examples 1-8) have a good pour point depressing effect on crude oil, with a large pour point depressing range, reaching more than 10°C. The pour point depressing effect is superior to that of the pour point depressants in Comparative Examples 1-11. The infrared spectrum of the first component in the pipeline crude oil pour point depressant of Example 3 is detailed below. Figure 1 For details, see the infrared spectrum of the second component in the pipeline crude oil pour point depressant in Example 3. Figure 2 For details, see the infrared spectrum of the third component in the pipeline crude oil pour point depressant in Example 3. Figure 3 .

[0090] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A pipeline crude oil pour point depressant, characterized in that, It includes the first component, the second component, the third component, and the fourth component; The first component is a terpolymer of ethylene, acrylate and vinyl acetate, the molecular weight of the first component is 10,000-15,000, and the mass ratio of ethylene, acrylate and vinyl acetate in the first component is (50-65):(5-8):(15-45). The acrylate is one or more of dodecyl acrylate, tetradecyl acrylate, hexadecyl acrylate and octadecyl acrylate. The second component is an amination product obtained by mixing a quaternary copolymer of maleic anhydride, vinylimidazole, acrylamide and methacrylate with an amine and then subjecting the mixture to an amination reaction at 100-160°C. The molecular weight of the second component is 8000-12000. The mass ratio of maleic anhydride, vinylimidazole, acrylamide and methacrylate in the second component is (10-15):(2-3):(1-2):(30-50). The methacrylate is one or more of dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate and octadecyl methacrylate. The amine is one or more of dodecylamine, tetradecylamine, hexadecylamine and octadecylamine. The third component is a polyether compound of ethylene oxide, propylene oxide and Guerbert alcohol, the molecular weight of the third component is 3000-8000, and the mass ratio of ethylene oxide, propylene oxide and Guerbert alcohol in the third component is (20-30):(40-50):(1-10). The fourth component is one or more of polymethylsilsesquioxane, sorbitan fatty acid ester, polyisobutylene succinic anhydride derivative, and ethylene glycol monobutyl ether. The mass ratio of the first component, the second component, the third component and the fourth component is (10-15): (35-55): (5-10): (1-5).

2. A method for preparing a pipeline crude oil pour point depressant, characterized in that, The method is used to prepare the pipeline crude oil pour point depressant according to claim 1, and the method includes the following steps: (1) Add acrylate, vinyl acetate, initiator and light aromatic solvent to a high-pressure reactor, heat to 80-150°C, and introduce ethylene gas to carry out the reaction. The mass ratio of ethylene, acrylate and vinyl acetate is (50-65):(5-8):(15-45). Then, use ethanol to perform hot washing at 50-70°C to remove unreacted monomers. Then, vacuum at 150-170°C to remove the solvent and obtain the first component. (2) Maleic anhydride, vinyl imidazole, acrylamide and methacrylate in a mass ratio of (10-15):(2-3):(1-2):(30-50) are dissolved in a light aromatic solvent, and azobisisobutyronitrile is added. Under nitrogen protection, a polymerization reaction is carried out at 60-90°C to obtain a quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate. Then, the quaternary copolymer of maleic anhydride, vinyl imidazole, acrylamide and methacrylate is mixed with amine and subjected to an amination reaction at 100-160°C. Then, the unreacted monomers are removed by hot washing with a methanol and water mixture in a weight ratio of 1:1 at 60-80°C. Then, the solvent is removed by vacuuming at 140-160°C to obtain the second component. (3) Add Gelbert alcohol and catalyst to a high-pressure reactor, heat to 110-130°C, and introduce propylene oxide and ethylene oxide to react. The mass ratio of ethylene oxide, propylene oxide and Gelbert alcohol is (20-30):(40-50):(1-10). Then, vacuum at 120-150°C to remove unreacted monomers and obtain the third component. (4) Dissolve the first component, the second component, the third component and the fourth component in a heavy aromatic solvent at a mass ratio of (10-15):(35-55):(5-10):(1-5) to obtain the pipeline crude oil pour point depressant.

3. The method for preparing the pipeline crude oil pour point depressant according to claim 2, characterized in that, The Gerbert alcohol is one or more of Gerbert dodecyl alcohol, Gerbert tetradecyl alcohol, Gerbert hexadecyl alcohol, and Gerbert octadecyl alcohol; The initiator is selected from at least one of benzoyl peroxide, lauroyl peroxide, benzoyl tert-butyl peroxide, methyl ethyl ketone peroxide, and di-tert-butyl peroxide; The light aromatic solvent is benzene, toluene, or xylene; The catalyst is sodium hydroxide and / or potassium hydroxide; The heavy aromatic solvent is No. 150 solvent oil.

4. The method for preparing the pipeline crude oil pour point depressant according to claim 2, characterized in that, The amount of the initiator added is 0.1–0.5 wt%; The amount of azobisisobutyronitrile added is 0.1–0.5 wt%; The molar ratio of the amine to maleic anhydride is (1-2):1; The catalyst is added in an amount of 0.3 to 0.6 wt%.

5. The application of the pipeline crude oil pour point depressant according to claim 1 in lowering the pour point of crude oil, wherein the dosage of the pipeline crude oil pour point depressant is 1700-1900 ppm.

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