An acrylate copolymer, its preparation method and application

Abstract

This invention provides an acrylate copolymer, its preparation method, and its application. The acrylate copolymer comprises polyoxyethylene ether structural units, acrylic acid structural units, hydrophobic monomer structural units, and crosslinking monomer structural units. The acrylate copolymer of this invention contains long-chain polyoxyethylene ether structures in its molecule, which enhances the hydrophilicity of the demulsifier, allowing it to quickly reach the oil-water interface and occupy a large surface area at the oil-water interface. This improves the demulsification and dehydration performance of the demulsifier on crude oil emulsions, reducing the demulsification temperature while maintaining the dehydration rate of the crude oil emulsion, thus achieving energy saving and consumption reduction.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemicals technology, and more specifically, to an acrylate copolymer, its preparation method, and its application. Background Technology

[0002] Adding a chemical agent to a crude oil emulsion to break it up is called chemical demulsification. This method can be used alone or in combination with other methods.

[0003] The research and application of demulsifiers has a history of more than 80 years. The molecular structure of demulsifiers has evolved from the initial anionic surfactants to block copolymers with propylene oxide and ethylene oxide as monomers after the 1940s, and now to high molecular weight nonionic surfactants, multi-component linear or three-dimensional polymers, zwitterionic polymers and their complexes, etc. The research on demulsifiers has made great progress.

[0004] Currently, demulsifiers researched both domestically and internationally are mainly nonionic polyoxyethylene and polyoxypropylene block polymers. my country's crude oil demulsifiers still suffer from problems such as limited variety, poor adaptability, and unstable quality, making the development of new, highly efficient crude oil demulsifiers an urgent necessity. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing an acrylate copolymer, its preparation method and application.

[0006] This invention utilizes polyoxyethylene ethers with double bonds at the end groups and acrylic acid as hydrophilic monomers, and acrylates as hydrophobic monomers, to synthesize acrylate copolymers via free radical polymerization. When a demulsifier containing this copolymer solution is used to treat water-in-oil crude oil emulsions, the copolymer simultaneously contains long-chain polyoxyethylene ethers, acrylic acid, acrylates, and crosslinking monomers, resulting in a comb-like branched polymer molecular structure. This enhances the surface activity of the demulsifier, improving its demulsification and dehydration performance on water-in-oil crude oil emulsions. While maintaining the dehydration rate of the crude oil emulsion, it lowers the demulsification temperature, thereby achieving energy saving and consumption reduction.

[0007] One objective of this invention is to provide an acrylate copolymer comprising polyoxyethylene ether structural units, acrylic acid structural units, hydrophobic monomer structural units, and crosslinking monomer structural units.

[0008] Based on the total weight of all structural units, the polyoxyethylene ether structural unit is 10–50 wt%, the acrylic structural unit is 1–20 wt%, the hydrophobic monomer structural unit is 45–85 wt%, and the crosslinking monomer structural unit is 0.01–3 wt%.

[0009] Preferably, the polyoxyethylene ether structural unit is 15-30 wt%, the acrylic structural unit is 1-10 wt%, the hydrophobic monomer structural unit is 60-80 wt%, and the crosslinking monomer structural unit is 0.01-1 wt%.

[0010] The acrylate copolymers of the present invention are formed by free radical polymerization of polyoxyethylene ether monomers with double bonds at the end groups, acrylic acid, hydrophobic monomers and crosslinking monomers.

[0011] The polyoxyethylene ether structural unit is derived from a polyoxyethylene ether monomer with a double bond at the end group, which is an allyl polyoxyethylene ether and / or polyethylene glycol monomethyl ether acrylate.

[0012] The acrylic structural unit is derived from acrylic acid.

[0013] The hydrophobic monomer structural unit is derived from a hydrophobic monomer, which is selected from at least one of butyl acrylate, methyl methacrylate, isooctyl acrylate, dodecyl acrylate, and octadecyl acrylate.

[0014] The crosslinking monomer structural unit is derived from the crosslinking monomer, which is an olefin containing two or more unsaturated double bonds, preferably at least one of diethylene glycol dimethacrylate, trimethylolpropionic acid triacrylate, butanediol dimethacrylate, divinylbenzene, butanediol diacrylate, acrylamide, N-hydroxymethylacrylamide, and N,N'-methylenebisacrylamide.

[0015] The second objective of this invention is to provide a method for preparing the acrylate copolymer, which involves free radical polymerization of components including a polyoxyethylene ether monomer with double bonds at the end groups, acrylic acid, a hydrophobic monomer, a crosslinking monomer, and an initiator.

[0016] The polyoxyethylene ether monomer with a double bond at the end group is allyl polyoxyethylene ether and / or polyethylene glycol monomethyl ether acrylate.

[0017] The hydrophobic monomer is selected from one or more of butyl acrylate, methyl methacrylate, isooctyl acrylate, dodecyl acrylate, and octadecyl acrylate.

[0018] The crosslinking monomer is an olefin containing two or more unsaturated double bonds, preferably one or more of diethylene glycol dimethacrylate, trimethylolpropionic acid triacrylate, butanediol dimethacrylate, divinylbenzene, butanediol diacrylate, acrylamide, N-hydroxymethylacrylamide, and N,N'-methylenebisacrylamide.

[0019] The initiator is selected from redox initiators and / or azo initiators. Preferably, the redox initiator is selected from benzoyl peroxide and / or benzoyl peroxide-dimethylaniline. The azo initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

[0020] According to some embodiments, based on the total monomer weight of the polyoxyethylene ether monomer with double bonds at the end group, acrylic acid, hydrophobic monomer and crosslinking monomer, the amount of the polyoxyethylene ether monomer with double bonds at the end group is 10-50 wt%, the amount of the hydrophobic monomer is 45-85 wt%, the amount of the acrylic acid is 1-20 wt%, and the amount of the crosslinking monomer is 0.01-3 wt%.

[0021] According to some preferred embodiments, based on the total monomer weight of the polyoxyethylene ether monomer with double bonds at the end group, acrylic acid, hydrophobic monomer and crosslinking monomer, the amount of polyoxyethylene ether with double bonds at the end group is 15-30 wt%, the amount of the hydrophobic monomer is 60-80 wt%, the amount of the acrylic acid is 1-10 wt%, and the amount of the crosslinking monomer is 0.01-1 wt%.

[0022] According to a preferred embodiment of the present invention, the preparation method includes the following steps:

[0023] (1) Dissolve the polyoxyethylene ether monomer with double bonds at the end group in a solvent and heat it; under an inert atmosphere, add an initiator to make the polyoxyethylene ether monomer with double bonds at the end group undergo a polymerization reaction.

[0024] (2) Add hydrophobic monomers, crosslinking monomers and initiators simultaneously to carry out the reaction;

[0025] (3) Add acrylic acid and an initiator, and continue the reaction to obtain an acrylate copolymer.

[0026] In step (1) of the preparation method described above, preferably:

[0027] The reaction temperature is 60–90℃, and the reaction time is 0.5–2 h;

[0028] The amount of initiator used is 0.2 to 1 wt%, based on the weight of the polyoxyethylene ether monomer with double bonds at the end groups.

[0029] In step (2) of the preparation method, preferably:

[0030] Based on the total weight of the hydrophobic monomer and the crosslinking monomer, the amount of initiator is 0.2 to 1 wt%.

[0031] The hydrophobic monomer and crosslinking monomer are dissolved in a solvent, and the initiator is dissolved in a solvent. Then, the above solutions are added dropwise to the system in step (1) at the same time, and the reaction time is 1 to 3 hours.

[0032] In step (3) of the preparation method, preferably:

[0033] Based on the weight of acrylic acid, the amount of initiator used is 5-15 wt%;

[0034] Dissolve acrylic acid and initiator in a solvent, and then add them dropwise to the system in step (2) over a period of 0.5 to 1 hour.

[0035] The reaction time is 2 to 5 hours.

[0036] According to some embodiments, the solvents described above are selected from one or more of toluene, N,N-dimethylformamide, butyl ether, anisole, butanone, ethyl acetate, and cyclohexanone.

[0037] A third objective of this invention is to provide the application of the acrylate copolymer or the acrylate copolymer obtained by the preparation method in crude oil demulsification.

[0038] The acrylate copolymer can be used alone or in combination with other demulsifiers known in the art.

[0039] The beneficial effects of this invention are:

[0040] The novel acrylate copolymer and its preparation method described in this invention utilize a solution free radical polymerization method with polyoxyethylene ethers containing double bonds at the end groups, hydrophobic monomers, acrylic acid, and crosslinking monomers. The resulting novel acrylate copolymer contains a long-chain polyoxyethylene ether structure in its molecule, which enhances the hydrophilicity of the demulsifier. Furthermore, the branched demulsifier has better interfacial activity than the linear demulsifier, allowing it to quickly reach the oil-water interface and occupy a large surface area at the oil-water interface. This improves the demulsification and dehydration performance of the demulsifier on crude oil emulsions, reducing the demulsification temperature while ensuring the dehydration rate of the crude oil emulsion, thus achieving the goal of energy saving and consumption reduction. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0042] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0043] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0044] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0045] According to a preferred embodiment of the present invention, the method for preparing the acrylate copolymer of the present invention may include the following steps:

[0046] Step 1: Dissolve the polyoxyethylene ether monomer with double bonds at the end group in a solvent to form a homogeneous solution, add it to the reactor, and heat it to 60-90°C, preferably 70-80°C.

[0047] Step 2: Under a nitrogen atmosphere and in the presence of an initiator, the polyoxyethylene ether monomers with double bonds at the end groups are polymerized for 0.5 to 2 hours.

[0048] Step 3: Add the solutions of hydrophobic acrylate monomers and crosslinking monomers, as well as the initiator solution, dropwise into the reactor simultaneously over 1-3 hours.

[0049] Step 4: The hydrophilic monomer of acrylic acid and the initiator solution are simultaneously added dropwise to the reactor, and the addition is completed over 0.5 to 1 hour. Continue the reaction for 2 to 5 hours, then discharge the product to obtain the copolymer solution.

[0050] According to some implementations, in step (2), the amount of initiator used is 0.2 to 1 wt% based on the weight of the polyoxyethylene ether monomer with double bonds at the end group.

[0051] In step (3), the amount of initiator used is 0.2 to 1 wt% based on the total weight of the hydrophobic monomer and the crosslinking monomer.

[0052] In step (4), the amount of initiator used is 5 to 15 wt% based on the weight of acrylic acid.

[0053] According to some embodiments, the solvent is selected from one or more of toluene, N,N-dimethylformamide, butyl ether, anisole, butanone, ethyl acetate, and cyclohexanone.

[0054] According to some embodiments, the amount of solvent used is 0.5 to 3 times the total weight of the acrylate hydrophobic monomer, the polyoxyethylene ether monomer with double bonds at the end group, the acrylic hydrophilic monomer, and the crosslinking monomer.

[0055] The testing method or calculation method provided by this invention is as follows:

[0056] Water yield (%) at different settling times = (water yield (ml) at different times / total water content in crude oil emulsion (ml)) × 100%.

[0057] Example 1

[0058] The method for preparing acrylate copolymers provided in this embodiment includes the following steps:

[0059] Step 1: Weigh 10 grams of methyl allyl polyoxyethylene ether (HPEG-2400) and 20 grams of N,N-dimethylformamide and add them to the reactor, stirring thoroughly until completely dissolved.

[0060] Step 2: Replace the air in the reactor with nitrogen and continuously introduce nitrogen. Heat the reactor to 70°C, add 0.06 g of azobisisobutyronitrile to start the reaction, and react at 70°C for 1 hour.

[0061] Step 3: Simultaneously add a solution of 25 g butyl acrylate, 15 g methyl methacrylate, 0.1 g trimethylolpropionic acid, and 50 g N,N-dimethylformamide, and a solution of 0.24 g azobisisobutyronitrile and 10 g N,N-dimethylformamide to the reactor dropwise over 2 hours.

[0062] Step 4: A solution of 2.4 g acrylic acid, 0.24 g azobisisobutyronitrile (AIB) initiator, and 2.5 g N,N-dimethylformamide is simultaneously added dropwise to the reactor over 0.5 hours. The reaction continues for 3 hours, and the product is discharged to obtain the copolymer solution.

[0063] Example 2

[0064] The method for preparing acrylate copolymers provided in this embodiment includes the following steps:

[0065] Step 1: Weigh 15g of methyl allyl polyoxyethylene ether (HPEG-2400) and 30g of N,N-dimethylformamide and add them to the reactor, stirring thoroughly until completely dissolved.

[0066] Step 2: Replace the air in the reactor with nitrogen and continuously introduce nitrogen. Heat the reactor to 70°C, add 0.09 g of azobisisobutyronitrile to start the reaction, and react at 70°C for 1 hour.

[0067] Step 3: A solution of 21 g butyl acrylate, 14 g isooctyl acrylate, 0.1 g trimethylolpropionic acid triacrylate and 45 g N,N-dimethylformamide, and a solution of 0.21 g azobisisobutyronitrile and 10 g N,N-dimethylformamide are simultaneously added dropwise to the reactor over 2 hours.

[0068] Step 4: 2.1 g of acrylic acid and 10 g of N,N-dimethylformamide solution, along with 0.21 g of azobisisobutyronitrile (AIBN) and 2.5 g of N,N-dimethylformamide solution as initiators, are simultaneously added dropwise to the reactor over 0.5 hours. The reaction continues for 3 hours, and the product is discharged to obtain the copolymer solution.

[0069] Example 3

[0070] Step 1: Weigh 15g of polyethylene glycol monomethyl ether acrylate and 30g of N,N-dimethylformamide and add them to the reactor, stirring thoroughly until completely dissolved.

[0071] Step 2: Replace the air in the reactor with nitrogen and continuously introduce nitrogen. Heat the reactor to 80°C, add 0.09 g of benzoyl peroxide to start the reaction, and react at 80°C for 1 hour.

[0072] Step 3: Add 21 g of butyl acrylate, 14 g of dodecyl acrylate, 0.1 g of trimethylolpropionic acid triacrylate, 45 g of N,N-dimethylformamide solution, 0.21 g of benzoyl peroxide, and 10 g of N,N-dimethylformamide solution dropwise to the reactor simultaneously over 2 hours.

[0073] Step 4: 2.1 g of acrylic acid, 0.21 g of benzoyl peroxide initiator, and 2.5 g of N,N-dimethylformamide solution are simultaneously added dropwise to the reactor over 0.5 hours. The reaction continues for 3 hours, and the product is discharged to obtain the copolymer solution.

[0074] Example 4

[0075] The method for preparing acrylate copolymers provided in this embodiment includes the following steps:

[0076] Step 1: Weigh 8 grams of methyl allyl polyoxyethylene ether (HPEG-2400) and 20 grams of N,N-dimethylformamide and add them to the reactor, stirring thoroughly until completely dissolved.

[0077] Step 2: Replace the air in the reactor with nitrogen and continuously introduce nitrogen. Heat the reactor to 80°C, add 0.048 g of benzoyl peroxide to start the reaction, and react at 80°C for 1 hour.

[0078] Step 3: Simultaneously add a solution of 21 g butyl acrylate, 21 g methyl methacrylate, 0.1 g trimethylolpropionic acid triacrylate and 50 g N,N-dimethylformamide, and a solution of 0.252 g benzoyl peroxide and 10 g N,N-dimethylformamide to the reactor dropwise over 2 hours.

[0079] Step 4: A solution of 5.5 g acrylic acid, 0.55 g benzoyl peroxide (initiator), and 2.5 g N,N-dimethylformamide is simultaneously added dropwise to the reactor over 0.5 hours. The reaction continues for 3 hours, and the product is discharged to obtain the copolymer solution.

[0080] Comparative Example 1

[0081] The demulsifier was prepared according to the method of Example 2 of CN111057577A.

[0082] Comparative Example 2

[0083] The demulsifier used at the Chengdong Joint Station of the Hekou Oil Production Plant in Shengli Oilfield is a modified polyether with a polyol as the initiator, provided by Shengli Chemical Hekou Branch.

[0084] Application Example 1

[0085] Heavy oil emulsions from the Chengdong Joint Station of the Hekou Oil Production Plant in Shengli Oilfield were demulsified using Examples 1-4 and Comparative Examples 1-2, respectively. The demulsification performance was evaluated according to the evaluation method specified in the petroleum and natural gas industry standard SY-Y5281-2000, "Performance Testing Method for Crude Oil Demulsifiers (Bottle Test Method)". The demulsification temperatures were 70℃ and 65℃, respectively. The results are shown in Tables 1 and 2.

[0086] Table 1 Evaluation results of demulsifying performance

[0087]

[0088] Table 2 Evaluation results of demulsifying performance

[0089]

[0090] (The concentration of demulsifier in the table refers to the amount of demulsifier used in 1L of heavy oil emulsion, calculated as the amount of copolymer solution in mg.) Experiments have shown that the acrylate copolymer prepared by the method of this invention, as a demulsifier, has a significantly higher demulsification effect on the heavy oil emulsion at Chengdong Joint Station than the demulsifiers used in Comparative Examples 1 and 2. Specifically, the demulsifier in Example 3 exhibits a significantly faster initial demulsification rate than other demulsifiers; at a low temperature of 65°C, the demulsification water yield of Example 3 can reach over 90% after 6 hours. When compounded with the demulsifier of Comparative Example 2, the demulsification effect of the resulting demulsifier is further improved.

[0091] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An acrylate copolymer comprising polyoxyethylene ether structural units, acrylic acid structural units, hydrophobic monomer structural units, and crosslinking monomer structural units; the acrylate copolymer is prepared by the following steps: (1) dissolving a polyoxyethylene ether monomer with double bonds at the end groups in a solvent and heating it; under an inert atmosphere, adding an initiator to polymerize the polyoxyethylene ether monomer with double bonds at the end groups; (2) simultaneously adding a hydrophobic monomer, a crosslinking monomer, and an initiator to react; (3) simultaneously adding acrylic acid and an initiator to continue the reaction to obtain the acrylate copolymer, wherein the hydrophobic monomer is selected from at least one of butyl acrylate, methyl methacrylate, isooctyl acrylate, dodecyl acrylate, and octadecyl acrylate; Based on the total weight of all structural units, the polyoxyethylene ether structural unit is 10~30wt%, the acrylic structural unit is 1~20wt%, the hydrophobic monomer structural unit is 45~85wt%, and the crosslinking monomer structural unit is 0.01~3wt%.

2. The acrylate copolymer according to claim 1, characterized in that: Based on the total weight of all structural units, the polyoxyethylene ether structural unit is 15~30wt%, the acrylic structural unit is 1~10wt%, the hydrophobic monomer structural unit is 60~80wt%, and the crosslinking monomer structural unit is 0.01~1wt%.

3. A method for preparing an acrylate copolymer according to any one of claims 1 to 2, comprising free radical polymerization of components including a polyoxyethylene ether monomer with a double bond at the end group, acrylic acid, a hydrophobic monomer, a crosslinking monomer and an initiator.

4. The preparation method according to claim 3, characterized in that: The polyoxyethylene ether monomer with a double bond at the end group is allyl polyoxyethylene ether and / or polyethylene glycol monomethyl ether acrylate; and / or, The crosslinking monomer is an olefin containing two or more unsaturated double bonds, selected from at least one of diethylene glycol dimethacrylate, trimethylolpropionic acid triacrylate, butanediol dimethacrylate, divinylbenzene, butanediol diacrylate, and N,N'-methylenebisacrylamide; and / or, The initiator is selected from redox initiators and / or azo initiators, wherein the redox initiator is benzoyl peroxide-N,N-dimethylaniline; and the azo initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

5. The preparation method according to any one of claims 3 to 4, characterized in that... The preparation method includes the following steps: (1) Dissolve the polyoxyethylene ether monomer with double bonds at the end group in a solvent and heat it; under an inert atmosphere, add an initiator to make the polyoxyethylene ether monomer with double bonds at the end group undergo a polymerization reaction. (2) Add hydrophobic monomers, crosslinking monomers and initiators simultaneously to carry out the reaction; (3) Simultaneously add acrylic acid and initiator, and continue the reaction to obtain acrylate copolymer.

6. The preparation method according to claim 5, characterized in that... In step (1): The polymerization reaction is carried out at a temperature of 60-90°C for a time of 0.5-2 hours. Based on the weight of the polyoxyethylene ether monomer with double bonds at the end groups, the amount of initiator is 0.2~1wt%.

7. The preparation method according to claim 5, characterized in that... In step (2): Based on the total weight of the hydrophobic monomer and the crosslinking monomer, the amount of initiator used is 0.2~1wt%; The reaction time is 1 to 3 hours.

8. The preparation method according to claim 5, characterized in that... In step (3), Based on the weight of acrylic acid, the amount of initiator used is 5~15 wt%; The addition time is 0.5~1h, and the reaction time is 2~5h.

9. The use of the acrylate copolymer according to any one of claims 1 to 2 or the acrylate copolymer obtained by the preparation method according to any one of claims 3 to 8 in crude oil demulsification.

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