A water-in-oil demulsifier, its preparation method and application

Abstract

The application discloses a water-in-oil demulsifier, a preparation method and application thereof. The water-in-oil demulsifier comprises a magnetic nanoparticle core and a protective layer and a modification layer which are sequentially coated outside the core, wherein the modification layer is a hydrophilic polymer layer. The water-in-oil demulsifier can demulsify in a short time, and the demulsifier recovered under the action of a magnetic field can be reused for multiple times, thereby reducing energy consumption and demulsifier consumption.

Description

Technical Field

[0001] This invention relates to the field of demulsifiers, and more specifically, to a water-in-oil demulsifier, its preparation method, and its application. Background Technology

[0002] Traditional demulsifiers separate oil and water in an emulsified oil-water mixture using surfactants or surface-active polymers, thereby achieving the purpose of crude oil dehydration.

[0003] As more and more oil fields around the world enter their late stages of development, enhanced oil recovery (EOR) technologies using various chemical agents are widely applied in oil fields to extract as much residual oil as possible from the formation. However, the extracted crude oil is often heavily emulsified, causing numerous problems for storage and transportation. To achieve rapid demulsification, the demulsification system often needs to be heated while adding demulsifiers, which not only consumes a large amount of energy but also poses safety hazards.

[0004] Magnetic nanoparticles are a new type of material that has developed rapidly in recent years and has great application value. They possess both magnetic and small-size properties.

[0005] Researchers at many renowned universities and companies internationally have been exploring the use of magnetic nanoparticles or their modified derivatives for low-temperature (room-temperature) demulsification. This research is still in its early stages, and while some progress has been made, it remains a long way from practical application (see Adewunmi, AA, MS Kamal, and TISolling, Journal of Petroleum Science and Engineering, 2021, 196).

[0006] Current research on the demulsification mechanism of low-temperature magnetic nanoparticle demulsifiers suggests that the surface properties of magnetic nanoparticles allow them to disperse well in the continuous phase of emulsions. Their high surface energy enables them to readily replace emulsifier molecules on the oil-water interface film after adsorption, forming a mixed film structure where the original surfactant and magnetic nanoparticles coexist. Under the influence of a magnetic field, the magnetic nanoparticles can attract droplet migration, accelerate droplet sedimentation, and promote film structure rupture, thereby destabilizing the emulsion. The specific process is described in [link to relevant documentation]. Figure 1 .

[0007] This invention does not assume that magnetic nanoparticles will behave as expected during the actual demulsification process. Figure 1 The magnetic nanoparticles are arranged at the interface. Furthermore, the arrangement of magnetic nanoparticles at the interface is affected by many factors, directly impacting the universality of the demulsifier. This invention designs a novel water-in-oil demulsifier that can rapidly demulsify under a low-temperature (<50℃) external magnetic field and can also be reused under the same external magnetic field, significantly reducing the amount of demulsifier used in oil extraction. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention provides an oil-in-water demulsifier, its preparation method, and its application, which solves the problem that heating is required when demulsifying crude oil emulsions in the prior art.

[0009] One objective of this invention is to provide a water-in-oil demulsifier comprising a magnetic nanoparticle core and a protective layer and a modifying layer sequentially wrapped around it, wherein the modifying layer is a hydrophilic polymer layer.

[0010] The water-in-oil demulsifier has a core-shell structure, with magnetic nanoparticles as the core, and a protective layer and a modification layer wrapped around them in sequence.

[0011] The modified layer is a hydrophilic polymer layer, wherein demulsifying segments are interspersed in the hydrophilic polymer layer.

[0012] The hydrophilic polymer layer is a hydrophilic polymer layer, preferably a polyoxyethylene ether, polyvinyl alcohol, or polyvinylpyrrolidone layer.

[0013] The thickness of the hydrophilic polymer layer is 1–30 nm, preferably 1–10 nm, and more preferably 1–5 nm.

[0014] The demulsifying chain segment has In the structure, R1 is a hydrophilic group, preferably oxyvinyl (-CH2CH2O-), vinyl alcohol (-CH(OH)CH2-), or vinylpyrrolidone. At least one of the following; X is N, S, or O; R2 is a lipophilic group, preferably oxypropenyl (-C3H6O-), oxybutenyl (-C4H8O-), or oxyhexenyl (-C6H 12 At least one of O-); Y is hydrogen, alkyl acyloxy, alkylphenol acyloxy, or oleoyl; m is an integer from 1 to 300, and n is an integer from 1 to 300.

[0015] The specific structure of the water-in-oil demulsifier can be shown below:

[0016]

[0017] In formula (I), R1 is a hydrophilic group;

[0018] R2 is a lipophilic group;

[0019] R3 is a magnetic nanoparticle;

[0020] R4 is a hydrophilic polymer layer;

[0021] R5 is the protective layer.

[0022] X is a bonding atom such as N, S, or O;

[0023] Y is a terminal group such as hydrogen, alkyl acyloxy, alkylphenol acyloxy, or oleoyl group.

[0024] In the above technical solution, R1 is preferably at least one of oxyvinyl alcohol, vinyl alcohol, and vinylpyrrolidone, and more preferably oxyvinyl alcohol.

[0025] In the above technical solution, R2 is preferably at least one of oxypropylene, oxybutenyl, and oxyhexenyl.

[0026] In the above technical solution, R3 is preferably a nano-sized magnetic particle, and more preferably a nano-sized superparamagnetic iron oxide particle.

[0027] In the above technical solution, R4 is preferably a hydrophilic layer of polyoxyethylene ether, polyvinyl alcohol, or polyvinylpyrrolidone.

[0028] In the above technical solution, R5 is preferably a siloxane protective layer, more preferably a protective layer containing only siloxane, a siloxane protective layer containing amino groups, or a polysiloxane protective layer containing epoxy groups.

[0029] In the above technical solution, m is preferably an integer from 1 to 300.

[0030] In the above technical solution, n is preferably an integer from 1 to 300.

[0031] The magnetic nanoparticles are Fe-Co alloy magnetic nanoparticles, Fe-Ni alloy magnetic nanoparticles, or iron-based magnetic nanoparticles. The magnetic nanoparticles are preferably iron oxide magnetic nanoparticles, Co-FeO4 magnetic nanoparticles, or MFe2O4 magnetic nanoparticles, wherein M is Mn, Mg, Zn, Co, or Fe.

[0032] There is no particular limitation on the particle size of the magnetic nanoparticles, but it is preferably 4 to 15 nm.

[0033] The protective layer is a siloxane protective layer, which is a shell formed by encapsulating a silane coupling agent around the core of a magnetic nanoparticle.

[0034] The thickness of the protective layer is the typical thickness of a protective layer, preferably 1–12 nm, and more preferably 1–8 nm.

[0035] A second objective of this invention is to provide a method for preparing the water-in-oil demulsifier, comprising the following steps:

[0036] (1) React magnetic nanoparticles with a silane coupling agent to form a protective layer on the surface of the magnetic nanoparticles.

[0037] (2) Add hydrophilic polymer and hydrophilic modifier to react. While forming a hydrophilic polymer layer on the protective layer, the hydrophilic modifier is interspersed in the hydrophilic polymer layer and modified on the protective layer. After the reaction is completed, continue to add lipophilic polymer.

[0038] In the preparation method, the magnetic nanoparticles can be prepared using methods commonly used in the art, such as precipitation.

[0039] According to a preferred embodiment of the present invention, ferrous chloride and ferric chloride are used as precursor compounds, dissolved in water, and then mixed with a surfactant and a hydrophobic solvent. A precipitant is added to obtain magnetic nanoparticles. A silane coupling agent is added to the obtained system containing magnetic nanoparticles, and the mixture is stirred at 15-40°C for 10-24 hours.

[0040] In step (1), the silane coupling agent is selected from silane coupling agents containing amino or epoxy groups, preferably at least one of KH550, KBM-602, KBM-603, Nanda-42, Nanda-73, A-1110, A-1120, and A-1130.

[0041] The mass ratio of the silane coupling agent to the magnetic nanoparticles is (0.8:1) to (20:1), preferably (1:1) to (10:1), and can specifically be 0.8:1, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, etc.

[0042] In step (2), the hydrophilic polymer is selected from at least one of short-chain glycidyl ether mono-terminated polyoxyethylene ether, short-chain glycidyl ether mono-terminated polyvinyl alcohol, and short-chain glycidyl ether mono-terminated polyvinylpyrrolidone.

[0043] The molecular weight of the hydrophilic polymer is 200 to 2000.

[0044] The mass ratio of the hydrophilic polymer to the magnetic nanoparticles is (0.1:1) to (20:1), preferably (0.1:1) to (5:1), and can specifically be 0.1:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, etc.

[0045] The hydrophilic modifier is selected from at least one of glycidyl ether double-terminated polyoxyethylene ether, glycidyl ether double-terminated polyvinyl alcohol, and glycidyl ether double-terminated polyvinylpyrrolidone.

[0046] The molecular weight of the hydrophilic modifier is 2000 to 100000.

[0047] The mass ratio of the hydrophilic modifier to the magnetic nanoparticles is (0.1:1) to (20:1), preferably (0.1:1) to (10:1), and can specifically be 0.1:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, etc.

[0048] The lipophilic polymer is selected from at least one of amino-terminated polyoxypropylene ether, aminooleoyloxy-terminated polyoxypropylene ether, aminostearoyloxy-terminated polyoxypropylene ether, and aminostearoyloxy-terminated polyoxybutene ether.

[0049] The mass ratio of the lipophilic polymer to the magnetic nanoparticles is (0.1:1) to (20:1), preferably (0.1:1) to (10:1), and can specifically be 0.1:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, etc.

[0050] In step (2), the reaction is carried out at 15-40°C, and a hydrophilic polymer and a hydrophilic modifier are added for 20-30 hours, followed by the addition of a lipophilic polymer for another 20-30 hours.

[0051] According to a preferred embodiment of the present invention, the preparation method includes the following steps:

[0052] The precursor compound for magnetic nanoparticles is dissolved in water and then dissolved in white oil, cyclohexane, or other hydrophobic solvents under the action of surfactants such as AOT (sodium (-2-ethylhexyl succinate) sulfonate) and sodium octadecyl chloride to form a reverse microemulsion. A basic compound is then added dropwise to induce a co-precipitation reaction, forming magnetic nanoparticles (the magnetic properties of the nanoparticles can vary from superparamagnetic to ferromagnetic by adjusting the reaction conditions). A silane coupling agent is then added to form a reverse microemulsion of acetic acid or ammonia, and a sol-gel reaction is used to form a siloxane protective shell on the surface of the magnetic nanoparticles. A short-chain hydrophilic polymer, a hydrophilic modifier containing R1 groups, and finally a lipophilic polymer containing R2 groups are added sequentially, followed by thorough stirring. The resulting reaction system can be used directly or after post-treatment.

[0053] A third objective of this invention is to provide the application of the aforementioned water-in-oil demulsifier in the demulsification of crude oil emulsions.

[0054] Based on crude oil emulsions, the amount of the water-in-oil demulsifier added is less than 0.2% wt.

[0055] The demulsification temperature is 5–50℃.

[0056] The water-in-oil demulsifier of this invention is used for demulsifying water-in-oil crude oil emulsions at low temperatures. Magnetic nanoparticles are added to the emulsified crude oil, stirred thoroughly, and then, under the action of an external magnetic field, the emulsified crude oil with the added magnetic nanoparticles will rapidly demulsify.

[0057] In the above technical solution, the water-in-oil demulsifier is suitable for crude oil emulsions in various blocks.

[0058] The water-in-oil demulsifier prepared using this invention can rapidly complete the demulsification process of crude oil emulsions at low temperatures under the action of an external magnetic field. The water-in-oil demulsifier of this invention can demulsify in a short time, and the demulsifier recovered under the action of a magnetic field can be reused multiple times, reducing energy consumption and the amount of demulsifier used, thus achieving good technical results.

[0059] The present invention will be further described below through specific embodiments. Attached Figure Description

[0060] Figure 1 Schematic diagram of the critical external magnetic force experiment. Detailed Implementation

[0061] 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.

[0062] 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.

[0063] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified were either readily available for purchase or prepared using methods disclosed in the prior art.

[0064]

Example 1

[0065] Dissolve 1.26 g of ferrous chloride and 3.25 g of ferric chloride in 10.5 g of deoxygenated deionized water. Transfer 2 g of AOT and 84.5 mL of cyclohexane to a 250 mL four-necked flask and stir until homogeneous. After the AOT is completely dissolved, add the dissolved ferrous chloride and ferric chloride solution dropwise to the flask and stir until homogeneous. Nitrogen protection is used during the addition. After the addition is complete, raise the system temperature to 40 °C. Slowly add 4 g of ammonia solution over approximately one hour. After stirring at 40 °C for 24 hours, add 3.5 g of acetic acid to neutralize the ammonia in the reaction solution. The resulting magnetite nanoparticles have an average particle size of 10 nm. Slowly add 2.5 g of KH550 under stirring, and after stirring at room temperature for 12 hours, slowly add acetic acid to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether mono-terminated polyoxyethylene ether (Mw approximately 600) and 0.5 g of glycidyl ether doubly-terminated polyoxyethylene ether (Mw approximately 7000) to the reaction solution. After stirring at room temperature for 24 hours, add 0.5 g of amino-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.3 nm and the thickness of the hydrophilic polymer layer is 1.1 nm.

[0066] Performance Test: 95g of Jiangsu Wei-5 crude oil, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 4.9g of water (30000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 4.9g of clear and transparent brine.

[0067]

Example 2

[0068] Dissolve 1.26 g of ferrous chloride and 3.25 g of ferric chloride in 10.5 g of deoxygenated deionized water. Transfer 2 g of Triton X-100 and 84.5 mL of white oil to a 250 mL four-necked flask and stir until homogeneous. After the Triton X-100 is completely dissolved, add the dissolved ferrous chloride and ferric chloride solution dropwise to the flask and stir until homogeneous. Nitrogen protection is used during the addition. After the addition is complete, raise the system temperature to 40 °C. Slowly add 4 g of ammonia water over approximately one hour. After stirring at 40 °C for 24 hours, add 3.5 g of acetic acid to neutralize the ammonia in the reaction solution. The resulting magnetite nanoparticles have an average particle size of 12 nm. Slowly add 2.6 g of Nanda-42 under stirring. After stirring at room temperature for 12 hours, slowly add acetic acid to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether mono-terminated polyoxyethylene ether (Mw approximately 600) and 0.5 g of glycidyl ether doubly-terminated polyoxyethylene ether (Mw approximately 7000) to the reaction solution. After stirring at room temperature for 24 hours, add 0.5 g of aminooleoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.6 nm and the thickness of the hydrophilic polymer layer is 1.1 nm.

[0069] Performance Testing: 90g of Shengli Gudong crude oil sample, 0.1g of SH-8 temperature-resistant and salt-resistant surfactant, and 9.9g of water (35000mg / l NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.7g of clear and transparent brine.

[0070]

Example 3

[0071] Dissolve 1.26 g of ferrous chloride and 3.25 g of ferric chloride in 10.5 g of deoxygenated deionized water. Transfer 2 g of Triton X-100 and 84.5 mL of diesel fuel to a 250 mL four-necked flask and stir until the Triton X-100 is completely dissolved. Then, add the dissolved ferrous chloride and ferric chloride solution dropwise to the flask and stir until homogeneous. Nitrogen gas is used for protection during the addition. After the addition is complete, raise the system temperature to 40°C. Slowly add 4 g of ammonia solution over approximately one hour. After stirring at 40°C for 24 hours, add 3.5 g of acetic acid to neutralize the ammonia in the reaction solution. The resulting magnetite nanoparticles have an average particle size of 13 nm. Slowly add 2.1 g of KBM-603 under stirring. After stirring at room temperature for 12 hours, slowly add acetic acid to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether-terminated polyvinyl alcohol (Mw approximately 800) and 0.5 g of glycidyl ether-terminated polyoxyethylene ether (Mw approximately 7000) to the reaction solution. After stirring at room temperature for 24 hours, add 0.5 g of aminooleoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.6 nm and the thickness of the hydrophilic polymer layer is 1.2 nm.

[0072] Performance Testing: 90g of Henan crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (5000mg / L NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.8g of clear and transparent brine.

[0073]

Example 4

[0074] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask under nitrogen protection. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution, resulting in magnetite nanoparticles with an average particle size of 14 nm. 2.6 g of A-1120 was then slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether-terminated polyvinyl alcohol (Mw approximately 600) and 0.5 g of glycidyl ether-terminated polyoxyethylene ether (Mw approximately 12000) to the reaction solution. After stirring at room temperature for 24 hours, add 0.5 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.9 nm and the thickness of the hydrophilic polymer layer is 1.2 nm.

[0075] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (18000mg / l NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.6g of clear and transparent brine.

[0076]

Example 5

[0077] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask under nitrogen protection. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution, resulting in magnetite nanoparticles with an average particle size of 14 nm. 2.6 g of A-1120 was then slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. 0.7 g of glycidyl ether-terminated polyvinyl alcohol (Mw approximately 600) and 0.5 g of glycidyl ether-terminated polyoxyethylene ether (Mw approximately 12000) were added to the reaction solution. After stirring at room temperature for 24 hours, 0.5 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) was added and stirred for another 24 hours. The reaction was then stopped to obtain the final product, in which the thickness of the protective layer was 1.9 nm and the thickness of the hydrophilic polymer layer was 1.3 nm.

[0078] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (18000mg / l NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.7g of clear and transparent brine.

[0079]

Example 6

[0080] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask under nitrogen protection. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution, resulting in magnetite nanoparticles with an average particle size of 14 nm. 2.6 g of A-1120 was then slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. Add 1 g of glycidyl ether mono-terminated polyvinylpyrrolidone (Mw approximately 600) and 4 g of glycidyl ether double-terminated polyoxyethylene ether (Mw approximately 12000) to the reaction solution. After stirring at room temperature for 24 hours, add 4 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.9 nm and the thickness of the hydrophilic polymer layer is 1.5 nm.

[0081] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (mineralization 18000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.8g of clear and transparent brine.

[0082]

Example 7

[0083] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask under nitrogen protection. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution, resulting in magnetite nanoparticles with an average particle size of 14 nm. 2.6 g of A-1120 was then slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. 1 g of glycidyl ether mono-terminated polyvinylpyrrolidone (Mw approximately 600) and 16 g of glycidyl ether double-terminated polyoxyethylene ether (Mw approximately 12000) were added to the reaction solution. After stirring at room temperature for 24 hours, 9 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) were added and stirred for another 24 hours. The reaction was then stopped to obtain the final product, in which the thickness of the protective layer was 1.9 nm and the thickness of the hydrophilic polymer layer was 1.5 nm.

[0084] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (18000mg / l NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.3g of clear and transparent brine.

[0085]

Example 8

[0086] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask under nitrogen protection. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution, resulting in magnetite nanoparticles with an average particle size of 14 nm. 2.6 g of A-1120 was then slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether mono-terminated polyvinylpyrrolidone (Mw approximately 600) and 0.5 g of glycidyl ether double-terminated polyoxyethylene ether (Mw approximately 12000) to the reaction solution. After stirring at room temperature for 24 hours, add 1 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.9 nm and the thickness of the hydrophilic polymer layer is 1.1 nm.

[0087] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (mineralization 18000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.8g of clear and transparent brine.

[0088]

Example 9

[0089] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask under nitrogen protection. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution, resulting in magnetite nanoparticles with an average particle size of 14 nm. 2.6 g of A-1120 was then slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether mono-terminated polyvinylpyrrolidone (Mw approximately 600) and 0.5 g of glycidyl ether double-terminated polyoxyethylene ether (Mw approximately 12000) to the reaction solution. After stirring at room temperature for 24 hours, add 0.3 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 1.9 nm and the thickness of the hydrophilic polymer layer is 1 nm.

[0090] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (18000mg / l NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.2g of clear and transparent brine.

[0091]

Example 10

[0092] 1.26 g of ferrous chloride and 3.25 g of ferric chloride were dissolved in 10.5 g of deoxygenated deionized water. 2 g of octadecylammonium chloride, 5 g of n-hexanol, and 79.5 mL of cyclohexane were transferred to a 250 mL four-necked flask and stirred until completely dissolved. The dissolved ferrous chloride and ferric chloride solution was then added dropwise to the flask and stirred until homogeneous. Nitrogen gas was used for protection during the addition. After the addition was complete, the system temperature was raised to 40 °C. 4 g of ammonia was slowly added dropwise over approximately one hour. After stirring at 40 °C for 24 hours, 3.5 g of acetic acid was added to neutralize the ammonia in the reaction solution. The resulting magnetite nanoparticles had an average particle size of 14 nm. 26 g of A-1120 was slowly added dropwise under stirring. After stirring at room temperature for 12 hours, acetic acid was slowly added dropwise to adjust the pH of the solution to 7–8. Add 1 g of glycidyl ether mono-terminated polyvinylpyrrolidone (Mw approximately 600) and 0.5 g of glycidyl ether double-terminated polyoxyethylene ether (Mw approximately 12000) to the reaction solution. After stirring at room temperature for 24 hours, add 0.3 g of aminostearoyloxy-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours. The reaction is then stopped to obtain the final product, in which the thickness of the protective layer is 8.6 nm and the thickness of the hydrophilic polymer layer is 1.5 nm.

[0093] Performance Testing: 90g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (18000mg / l NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.3g of clear and transparent brine.

[0094]

Example 11

[0095] Dissolve 1.26 g of ferrous chloride and 3.25 g of ferric chloride in 10.5 g of deoxygenated deionized water. Transfer 2 g of AOT and 84.5 mL of cyclohexane to a 250 mL four-necked flask and stir until completely dissolved. Then, add the dissolved ferrous chloride and ferric chloride solution dropwise to the flask and stir until homogeneous. Nitrogen gas is used for protection during the addition. After the addition is complete, raise the system temperature to 40 °C. Slowly add 4 g of ammonia solution over approximately one hour. After stirring at 40 °C for 24 hours, add 3.5 g of acetic acid to neutralize the ammonia in the reaction solution. The resulting magnetite nanoparticles have an average particle size of 10 nm. Slowly add 2.3 g of A-1120 under stirring. After stirring at room temperature for 12 hours, slowly add acetic acid to adjust the pH of the solution to 7–8. Add 1 gram of glycidyl ether mono-terminated polyoxyethylene ether (Mw approximately 600) and 8 grams of glycidyl ether doubly-terminated polyoxyethylene ether (Mw approximately 7000) to the reaction solution. After stirring at room temperature for 24 hours, add 8 grams of amino-terminated polyoxypropylene ether (Mw approximately 7000) and stir for another 24 hours to complete the reaction and obtain the final product. The thickness of the protective layer is 1.3 nm and the thickness of the hydrophilic polymer layer is 1.5 nm.

[0096] Performance testing:

[0097] 1) 90g of crude oil sample from Changqing Oilfield, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (38000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.7g of clear and transparent brine.

[0098] A crude oil sample from Changqing Oilfield was reused, along with 0.1 g of SH-6 temperature-resistant and salt-resistant surfactant and 9.9 g of water (38000 mg / L NaCl). The mixture was added to a 250 mL beaker and stirred at 3000 rpm to form a crude oil emulsion. Then, the previously used magnetic nanoparticle demulsifier was added to the crude oil emulsion, and the mixture was stirred at 500 rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The crude oil quickly gathered to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, and the crude oil gathered at the bottom of the beaker was also poured out and weighed. This process was repeated 9 times. The collected magnetic nanoparticles still effectively broke the crude oil emulsion, and the demulsification effect remained essentially unchanged. The specific results are shown in Table 1 below.

[0099] Table 1

[0100]

[0101] 2) 90g of crude oil sample from Henan Oilfield, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (8000mg / L NaCl) were added to a 250ml beaker. The mixture was stirred at 3000rpm using a high-speed stirrer to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.6g of clear and transparent brine.

[0102] A crude oil sample from the Henan Oilfield was reused, along with 0.1 g of SH-6 temperature-resistant and salt-resistant surfactant and 9.9 g of water (8000 mg / L NaCl). The mixture was added to a 250 mL beaker and stirred at 3000 rpm to form a crude oil emulsion. Then, the previously used magnetic nanoparticle demulsifier was added to the crude oil emulsion, and the mixture was stirred at 500 rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, and the crude oil that had accumulated to the bottom of the beaker was also poured out and weighed. This process was repeated 9 times. The collected magnetic nanoparticles still effectively broke the crude oil emulsion, and the demulsification effect remained essentially unchanged. The specific results are shown in Table 2 below.

[0103] Table 2

[0104]

[0105] 3) 90g of Shengli Gudong crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9g of water (mineralization 30000mg / l NaCl, 300mg / l CaCl2) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthetic nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 9.6g of clear and transparent brine.

[0106] A 250 mL beaker was filled with 90 g of Shengli Gudong crude oil sample, 0.1 g of SH-6 temperature-resistant and salt-resistant surfactant, and 9.9 g of water (30000 mg / L NaCl, 300 mg / L CaCl2). The mixture was stirred at 3000 rpm to form a crude oil emulsion. Then, the previously used magnetic nanoparticle demulsifier was added to the crude oil emulsion, and the mixture was stirred at 500 rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, and the crude oil that had accumulated to the bottom of the beaker was also poured out and weighed. This process was repeated 9 times. The collected magnetic nanoparticles still effectively broke the crude oil emulsion, and the demulsification effect remained essentially unchanged. The specific results are shown in Table 3 below.

[0107] Table 3

[0108]

[0109] Comparative Example 1

[0110] Dissolve 1.26 g of ferrous chloride and 3.25 g of ferric chloride in 10.5 g of deoxygenated deionized water. Transfer 2 g of AOT and 84.5 mL of cyclohexane to a 250 mL four-necked flask and stir until homogeneous. After the AOT is completely dissolved, add the dissolved ferrous chloride and ferric chloride solution dropwise to the flask and stir until homogeneous. Nitrogen protection is used during the addition. After the addition is complete, raise the system temperature to 40 °C. Slowly add 4 g of ammonia solution over approximately one hour. After stirring at 40 °C for 24 hours, add 3.5 g of acetic acid to neutralize the ammonia in the reaction solution. The resulting iron oxide magnetic nanoparticles have an average particle size of 10 nm. Slowly add 2.5 g of KH550 under stirring, and after stirring at room temperature for 12 hours, slowly add acetic acid to adjust the pH of the solution to 7–8. Add 0.5 g of glycidyl ether-terminated polyoxyethylene ether (Mw approximately 7000) to the reaction solution, stir at room temperature for 24 hours, then add 0.5 g of amino-terminated polyoxypropylene ether (Mw approximately 7000), stir for another 24 hours, and the reaction is complete to obtain the final product.

[0111] Performance testing:

[0112] 1) 95g of Jiangsu Wei-5 crude oil, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 4.9g of water (30000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthesized nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. Some of the brine was observed to concentrate at the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 4.2g of clear and transparent brine. Compared to this test, the demulsifier sample synthesized in Example 1 was able to remove all 4.9g of brine from the crude oil emulsion under the same conditions.

[0113] 2) 95g of Henan Ming-15 crude oil sample, 0.1g of SH-6 temperature-resistant and salt-resistant surfactant, and 4.9g of water (mineralization 18000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthesized nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine was observed to concentrate at the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 4.6g of clear and transparent brine. The demulsifier sample synthesized in Example 1 was able to remove all 4.9g of brine from the crude oil emulsion under the same conditions.

[0114] 3) 95g of Shengli Gudong crude oil sample, 0.1g of SH-8 temperature-resistant and salt-resistant surfactant, and 4.9g of water (35000mg / l NaCl) were added to a 250ml beaker and stirred at 3000rpm to form a crude oil emulsion. Then, 50mg of synthesized nano-magnetic particle demulsifier was added, and the mixture was stirred at 500rpm for 10 minutes on a magnetic stirrer before being placed on a U85 teaching magnet. The brine quickly concentrated to the bottom of the beaker. After standing for 15 minutes, the separated brine was poured out and weighed, yielding 4.9g of clear and transparent brine. Compared to this test, the demulsifier sample synthesized in Example 1 was also able to remove all 4.9g of brine from the crude oil emulsion under the same conditions.

[0115] The demulsifier of this invention is chemically linked from core-shell magnetic nanoparticles, hydrophilic polymer fragments, and lipophilic polymer fragments. When added to crude oil emulsions (at a concentration of less than 0.2% wt) at a temperature range of 5°C to 50°C and stirred, the demulsifier can be demulsified in a short time under the influence of a magnetic field. The demulsifier recovered under the influence of the magnetic field can be reused multiple times.

Claims

1. A water-in-oil demulsifier, comprising a magnetic nanoparticle core and a protective layer and a modifying layer sequentially coated thereon, wherein the modifying layer is a hydrophilic polymer layer, and demulsifying segments are interspersed within the hydrophilic polymer layer, the demulsifying segments being modified onto the protective layer; the demulsifying segments have The structure includes: R1, a hydrophilic group selected from oxyvinyl, vinyl alcohol, and vinylpyrrolidone; X, N, S, or O; R2, a lipophilic group selected from oxypropylene, oxybutenyl, and oxyhexenyl; Y, hydrogen, alkyl acyloxy, alkylphenol acyloxy, or oleoyl; m, an integer from 1 to 300; n, an integer from 1 to 300; and a siloxane protective layer.

2. The water-in-oil demulsifier according to claim 1, characterized in that: The hydrophilic polymer layer is a polyoxyethylene ether, polyvinyl alcohol, or polyvinylpyrrolidone layer; and / or, The thickness of the hydrophilic polymer layer is 1~30nm.

3. The water-in-oil demulsifier according to claim 1, characterized in that: The magnetic nanoparticles are iron-based magnetic nanoparticles.

4. The water-in-oil demulsifier according to claim 3, characterized in that: The magnetic nanoparticles are Fe-Co alloy magnetic nanoparticles or Fe-Ni alloy magnetic nanoparticles.

5. The water-in-oil demulsifier according to claim 3, characterized in that: The magnetic nanoparticles are iron oxide magnetic nanoparticles or MFe2O4 magnetic nanoparticles, wherein M is Mn, Mg, Zn, or Co; and / or, The magnetic nanoparticles have an average particle size of 4-15 nm; and / or, The thickness of the protective layer is 1~12nm.

6. A method for preparing a water-in-oil demulsifier according to any one of claims 1 to 5, comprising the following steps: (1) React magnetic nanoparticles with a silane coupling agent to form a protective layer on the surface of the magnetic nanoparticles; (2) Add hydrophilic polymer and hydrophilic modifier to react and form a hydrophilic polymer layer on the protective layer. At the same time, the hydrophilic modifier is interspersed in the hydrophilic polymer layer and modified on the protective layer. After the reaction is completed, continue to add lipophilic polymer.

7. The preparation method according to claim 6, characterized in that... Step (1): The silane coupling agent is selected from at least one of KH550, KBM-602, KBM-603, Nanda-42, Nanda-73, A-1110, A-1120, and A-1130; and / or, The mass ratio of the silane coupling agent to the magnetic nanoparticles is (0.8:1) to (20:1).

8. The preparation method according to claim 7, characterized in that: The mass ratio of the silane coupling agent to the magnetic nanoparticles is (1:1) to (10:1).

9. The preparation method according to claim 6, characterized in that... In step (2): The hydrophilic polymer has a molecular weight of 200-2000, and is selected from one of short-chain glycidyl ether mono-terminated polyoxyethylene ether, short-chain glycidyl ether mono-terminated polyvinyl alcohol, and short-chain glycidyl ether mono-terminated polyvinylpyrrolidone; and / or, The mass ratio of the hydrophilic polymer to the magnetic nanoparticles is (0.1:1) to (20:1).

10. The preparation method according to claim 9, characterized in that: The mass ratio of the hydrophilic polymer to the magnetic nanoparticles is (0.1:1) to (5:1).

11. The preparation method according to claim 6, characterized in that... In step (2): The hydrophilic modifier is selected from one of glycidyl ether double-terminated polyoxyethylene ether, glycidyl ether double-terminated polyvinyl alcohol, and glycidyl ether double-terminated polyvinylpyrrolidone; and / or, The hydrophilic modifier has a molecular weight of 2000~100000; and / or, The mass ratio of the hydrophilic modifier to the magnetic nanoparticles is (0.1:1) to (20:1); and / or, The lipophilic polymer is selected from one of the following: amino-terminated polyoxypropylene ether, aminooleoyloxy-terminated polyoxypropylene ether, aminostearoyloxy-terminated polyoxypropylene ether, and aminostearoyloxy-terminated polyoxybutene ether; and / or The mass ratio of the lipophilic polymer to the magnetic nanoparticles is (0.1:1) to (20:1).

12. The preparation method according to claim 11, characterized in that: The mass ratio of the hydrophilic modifier to the magnetic nanoparticles is (0.1:1) to (10:1); and / or, The mass ratio of the lipophilic polymer to the magnetic nanoparticles is (0.1:1) to (10:1).

13. The use of the water-in-oil demulsifier according to any one of claims 1 to 5 in the demulsification of crude oil emulsions.

14. The application according to claim 13, characterized in that: Based on crude oil emulsions, the amount of the water-in-oil demulsifier added is less than 0.2% wt; The demulsification temperature is 5~50℃.

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