Preparation method of modified magnetic particles and method for continuous demulsification of the modified magnetic particles

Abstract

The present application provides a method for preparing modified magnetic particles and a method for continuous demulsification of the modified magnetic particles, including: adding vinyltrimethoxysilane to absolute ethanol and stirring to obtain solution A; adding perfluorooctanoic acid and sodium hydroxide to absolute ethanol and stirring to obtain solution B; adding magnetic particles to the mixed solution of solution A and solution B, transferring it to a reaction kettle, placing it at 80-90 °C and keeping warm for 0.5-2 h, cooling, and drying to obtain modified magnetic particles; applying the modified magnetic particles to the method of turbulent dispersion continuous demulsification, pumping the emulsion into a stirring tank through a peristaltic pump to mix with M-MMPs, and the hydraulic retention time in the stirring tank is greater than or equal to 30 s; controlling the surface magnetic field intensity of the electromagnet above 400 Gs, the height of the separation chamber is less than 5 cm, the hydraulic retention time of the emulsion in the separation chamber is greater than 30 s, and collecting the separated oil and water; preventing the modified magnetic particles from gradually adhering to the wall surface of the separation chamber to achieve the optimal separation effect.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic particle demulsification, and particularly relates to a preparation method of modified magnetic particles and a method for continuous demulsification of the modified magnetic particles. Background Art

[0002] Magnetic nanoparticles (MNPs) have achieved good demulsification effects in bottle test demulsification tests and have demonstrated environmentally friendly characteristics of recyclability and pollution-free. However, problems such as the high preparation cost of modified MNPs and the low number of recycling times limit their industrial applications in the oil-water separation field. In comparison, the cost of treating oil-in-water emulsions (O / W) with MNPs is 7.8 to 34.4 times that of magnetic microparticles (MMPs).

[0003] On the one hand, MMPs have a high price advantage compared to MNPs; on the other hand, MMPs have a lower surface energy and are more affected by turbulent dispersion, and the difficulty of dispersion and recovery in the emulsion is lower. Therefore, weakening the particle agglomeration effect caused by particle surface contamination and increasing the particle size of magnetic particles are effective ways to realize the industrial application of magnetic particles in the oil-water separation field.

[0004] However, the demulsification treatment of water-in-oil emulsions (W / O) cannot be continuously separated, and its separation efficiency rapidly decreases with the number of separation times. Summary of the Invention

[0005] Embodiments of the present application provide a preparation method of modified magnetic particles, a method for continuous demulsification of modified magnetic particles based on turbulent dispersion and its application, to solve the technical problems in the prior art that the separation efficiency of magnetic particles for shale oil emulsions is low, and as the separation time increases, the magnetic particles will gradually adhere to the wall of the separation chamber, resulting in a gradual decrease in the separation efficiency.

[0006] In a first aspect, embodiments of the present application provide a preparation method of modified magnetic particles, and the method includes:

[0007] S101. Add vinyltrimethoxysilane (VTMO, chemically pure) to anhydrous ethanol (analytically pure) and stir to obtain solution A;

[0008] S102. Add perfluorooctanoic acid (PFOA, chemically pure) and sodium hydroxide (NaOH, analytically pure) to anhydrous ethanol and stir to obtain solution B;

[0009] S103. Add magnetic particles to the mixed solution of solution A and solution B, transfer it to a reaction kettle, place it at 80 - 90 °C and keep it warm for 0.5 - 2 h, cool, and dry to obtain the modified magnetic particles (M-MMPs).

[0010] In an alternative embodiment, the magnetic particles are magnetic micron-sized magnetite particles (Fe 3 O 4 ).

[0011] In an alternative embodiment, the volume ratio of vinyltrimethoxysilane (VTMO) to absolute ethanol is 0.1:(10 - 20);

[0012] and / or, the mass-volume ratio of perfluorooctanoic acid (PFOA), sodium hydroxide and absolute ethanol is 1 g:(0.1 - 0.15) g:(20 - 35) mL.

[0013] In a second aspect, an embodiment of the present application provides a modified magnetic particle, which is prepared by the method described in any one of the embodiments of the first aspect of the present application.

[0014] In an alternative embodiment, the contact angle of the modified magnetic particle with oil is above 140°;

[0015] In an alternative embodiment, the separation temperature of the modified magnetic particle for separating the water-in-oil emulsion is 20 - 60 °C.

[0016] In a third aspect, an embodiment of the present application provides a method for continuous demulsification based on turbulent dispersion. The modified magnetic particles prepared by the method described in any one of the embodiments of the first aspect of the present application, and / or the modified magnetic particles described in any one of the embodiments of the second aspect of the present application, are applied in continuous demulsification based on turbulent dispersion, including:

[0017] S201. A peristaltic pump pumps the emulsion into a stirring tank for mixing with the modified magnetic particles, and the hydraulic retention time in the stirring tank is greater than or equal to 30 s;

[0018] S202. The surface magnetic field intensity of the electromagnet is controlled above 400 Gs, the height of the separation chamber is less than 5 cm, and the hydraulic retention time of the emulsion in the separation chamber is greater than 30 s;

[0019] S203. After magnetic separation, the modified magnetic particles are deposited at the bottom of the funnel of the separation chamber. The separated water is discharged into a water collection tank through a pipeline below the side of the separation chamber, and the separated oil is discharged into an oil collection tank through a pipeline above the side.

[0020] In an alternative embodiment, the length of the stirring paddle blades in the stirring tank is greater than 1 / 4 of the radius of the stirring tank.

[0021] In an alternative embodiment, the stirring speed of the stirring tank is controlled within 300 - 1000 rpm to ensure that stirring does not cause further fragmentation of the droplets.

[0022] In an alternative embodiment, in the stirring tank, the concentration of the modified magnetic particles is greater than 0.025 g / mL.

[0023] Compared with the prior art, the present application also has the following beneficial effects:

[0024] 1. The emulsion used in the present application is a shale oil-in-water emulsion. The average particle size of the emulsion droplets ranges from 5 to 72 μm, and the separation efficiency decreases as the average particle size of the emulsion decreases. After hydrophilic / oil-phobic surface modification, the Fe 3 O 4 particles of the present application have a contact angle with oil above 140° and a contact angle with water below 20°. The separation efficiency of the modified Fe 3 O 4 particles is up to 40% higher than that of the unmodified Fe 3 O 4 particles. Moreover, after 9 cycles of reuse, the separation efficiency does not decrease, and the number of recyclable times is stronger than that of most magnetic nanoparticle demulsifiers. The separation temperature is 40 - 60 °C, and the viscosity of the oil is 6 - 23.6 mPa·S.

[0025] 2. After separation in the present application, close the oil and water valves of the separation chamber and the electromagnet at the bottom of the separation chamber, and open the pipeline valve at the bottom of the separation chamber to discharge the magnetic particles into the magnetic particle collection tank. Subsequently, they can be directly added to the stirring tank for reuse without any cleaning. One stirring tank with two separation chambers alternately discharging magnetic particles and demulsifying with a magnetic field can achieve long-term continuous demulsification of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0027] Figure 1 Process flow chart of the preparation method of the modified magnetic particles provided by the embodiment of the present application;

[0028] Figure 2 Wettability of the magnetic particle sample and the modified magnetic particle sample with water and white oil provided by the embodiment of the present application (a) and (b);

[0029] Figure 3 Contact angle of the magnetic particle sample with white oil (a) and contact angle of the modified magnetic particle sample with water droplets (b) provided by the embodiment of the present application;

[0030] Figure 4 Test curve graph of the influence of shear speed on the separation efficiency of magnetic particles (MMPs) and modified magnetic particles (M-MMPs) provided by the embodiment of the present application;

[0031] Figure 5 It is a test curve graph of the separation efficiency of temperature-influenced modified magnetic particles (M-MMPs) provided by the embodiments of the present application;

[0032] Figure 6 It is a flowchart of the method for continuous demulsification based on modified magnetic particles provided by the embodiments of the present application;

[0033] Figure 7 It is a schematic diagram of the experimental device for the method of continuous demulsification based on modified magnetic particles provided by the embodiments of the present application;

[0034] Figure 8 It is a test curve graph of the separation efficiency of the method for continuous demulsification based on modified magnetic particles provided by the embodiments of the present application.

[0035] Description of the reference numerals:

[0036] 1 — emulsion tank;

[0037] 2 — peristaltic pump;

[0038] 3 — stirring tank;

[0039] 4-1, 4-2 — electromagnets;

[0040] 5-1, 5-2 — separation chambers;

[0041] 6 — magnetic particle collection tank;

[0042] 7 — oil collection tank;

[0043] 8 — water collection tank;

[0044] 9 — power supply;

[0045] 10 — electromagnet controller.

[0046] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and the written description are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0047] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all the implementation manners consistent with the present application. On the contrary, they are only examples of the devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0048] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0049] Embodiment

[0050] A preparation method of modified magnetic particles, the preparation method includes the following steps:

[0051] Add 100 μL of VTMO to 15 mL of absolute ethanol, stir for 0.5 h, and name it solution A.

[0052] Take 0.5 g of PFOA and 0.05 g of NaOH and put them into 15 mL of absolute ethanol, and stir for 0.5 h at the same time, and name it solution B.

[0053] Slowly drop solution A into solution B, and stir for 0.5 h to obtain a mixed solution C. Put the Fe 3 O 4 particles and the mixed solution C into a hydrothermal reaction kettle together, and put the hydrothermal reaction kettle into an oven at 80 °C for heat preservation for 1 h. After cooling, take out the Fe 3 O 4 particles and dry them to obtain M-MMPs.

[0054] Comparative Example

[0055] Fe 3 O 4 particles with the same mesh number as those in the above embodiment are purchased from the market. After drying, MMPs are obtained.

[0056] In order to compare with the modified magnetic particles (M-MMPs) obtained in the above embodiment, unmodified magnetic particles are used for comparative performance testing.

[0057] The white oil (mineral oil) used in the present application is purchased from Mojiezu Petrochemical (Shanghai) Co., Ltd. Wahaha purified water is purchased from Wahaha Co., Ltd.

[0058] The shale oil produced fluid is taken from Dongxin Oil Production Plant of Shengli Oilfield in Jiyang, China. The surface tensions of shale oil and produced water in the shale oil produced fluid are measured by the sessile drop method, and the liquid viscosity is measured by a rotational viscometer (NDJ-8s). The physical property parameters of the liquid are shown in Table 1.

[0059] Table 1. Physical property parameters of shale oil and produced water

[0060]

[0061] For the M-MMPs prepared in the above embodiments and the MMPs obtained in the comparative examples, the following performance tests were carried out.

[0062] 1. Drop the above white oil and pure water onto M-MMPs and MMPs respectively, and observe the wettability of M-MMPs and MMPs.

[0063] As Figure 2 can be observed, for MMPs, both the oil droplet and the water droplet showed good wettability to the MMPs sample; while for M-MMPs, the water droplet could still penetrate into the M-MMPs sample, while the oil droplet could hardly wet the M-MMPs sample. It shows that after modification, the Fe 3 O 4 particles changed from amphiphilic to hydrophilic / oil-phobic properties.

[0064] 2. Measure the contact angles of the oil droplet and the water droplet on M-MMPs.

[0065] As Figure 3 shown, after the oil droplet stabilized on the M-MMPs sample, the measured average contact angle reached 141.21°. After the water droplet contacted the M-MMPs sample, it would gradually completely wet the M-MMPs sample. Further measurement showed that the average contact angle of the M-MMPs sample at 1.5 s was 20.34°. This further shows that after modification, the Fe 3 O 4 particles (M-MMPs) changed from amphiphilic to hydrophilic / oil-phobic properties, and M-MMPs have excellent hydrophilic and oil-phobic properties.

[0066] 3. Dehydration efficiency performance test.

[0067] Under the condition of 60 °C, add MMPs and M-MMPs with a dosage of m = 3.33 g / mL respectively, and use MMPs and M-MMPs at different shear rotation speeds to separate the prepared shale oil emulsion.

[0068] The test results are as Figure 4 shown. From the curve of the separation efficiency E changing with the shear rotation speed ω, it can be seen that as the shear rotation speed increases, the separation efficiencies of both MMPs and M-MMPs decrease, but the decrease amplitude of the separation efficiency of M-MMPs is smaller, indicating that M-MMPs have more stable separation performance and its separation effect is less affected by the rotation speed.

[0069] Furthermore, through testing, it can be seen that when the shear rotation speed ω < 2000 rpm, the separation efficiency of MMPs and M-MMPs is almost the same; after continuously increasing the shear rotation speed, when the shear rotation speed ω ≥ 3000 rpm, M-MMPs show better separation performance than MMPs; and in the case of the shear rotation speed ω = 5000 rpm, the separation efficiency of M-MMPs is 40% higher than that of MMPs, and the separation efficiency of M-MMPs gradually stabilizes when the shear rate ω ≥ 3000 rpm and is less affected by the shear rotation speed.

[0070] 4. Influence of temperature on separation efficiency.

[0071] Generally, for magnetic particles, an increase in temperature is beneficial to reducing the viscosity of the continuous oil phase, enhancing the coalescence of water droplets in the emulsion, and reducing the strength of the oil-water interfacial film, thereby improving the oil-water separation efficiency, but it will also increase the energy consumption and economic cost of oil-water separation.

[0072] However, for emulsions with a low pour point temperature such as shale oil, low-temperature demulsification is the key to reducing energy consumption. Since the pour point of the shale oil used is 28 °C and its fluidity is poor at about 35 °C, demulsification tests were carried out at 40 - 60 °C. First, M-MMPs with a test dosage of m = 3.33 g / mL were added, and the shear rotation speed ω = 2000 rpm was set, and demulsification was carried out at temperatures of 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, etc. The test results are as Figure 5 shown.

[0073] As Figure 5 shown, it can be seen from the broken line graph of the separation efficiency of M-MMPs at different temperatures that the separation efficiency changes basically linearly with temperature. The separation efficiency is the lowest at 40 °C, which is 60%, and the highest at 60 °C, which is 77%. The separation efficiency is less affected by temperature, and a separation efficiency of 60% can be achieved when the temperature is 10 °C higher than the pour point of shale oil.

[0074] 5. Test of cyclic separation performance.

[0075] Under the condition of 60 °C, with the dosage of M-MMPs being m = 3.33 g / mL, the emulsion prepared at the shear rotation speed ω = 2000 rpm was separated. After each separation, the M-MMPs were adsorbed to the bottom of the sample bottle using a magnet, and the separated emulsion was poured out. Without any cleaning work on the M-MMPs, the newly prepared emulsion was poured in for the next separation.

[0076] The test results show that the separation efficiency of M-MMPs remains basically unchanged during 10 separations. After 10 cycles, its separation efficiency can still reach more than 80%, and M-MMPs show excellent recyclability.

[0077] Since M-MMPs and MMPs have a small size and exhibit certain Brownian motion characteristics in liquids, the collision of magnetic particles with water droplets is affected by the dispersibility of magnetic particles and the double electric layer at the oil-water interface. In order to minimize the above effects and achieve better demulsification during the demulsification process of the magnetic particles of the present application, an embodiment of the present application also proposes a continuous demulsification method of modified magnetic particles based on turbulent dispersion, as Figure 6 shown, the method includes:

[0078] The peristaltic pump 2 pumps the emulsion into the stirring tank 3 for mixing with the modified magnetic particles, and the hydraulic residence time in the stirring tank 3 is greater than or equal to 30 s.

[0079] The surface magnetic field intensity of the electromagnets 4-1 and 4-2 is controlled above 400 Gs, the height of the separation chambers 5-1 and 5-2 is less than 5 cm, and the hydraulic residence time of the emulsion in the separation chambers 5-1 and 5-2 is greater than 30 s.

[0080] After magnetic separation, the modified magnetic particles are deposited at the bottom of the funnels of the separation chambers 5-1 and 5-2. The separated water is discharged into the water collection tank 8 through the pipeline below the side of the separation chamber, and the separated oil is discharged into the oil collection tank 7 through the pipeline above the side.

[0081] Furthermore, the above method is combined with the experimental device as Figure 7 shown. The prepared modified magnetic particles are mixed with the emulsion by the peristaltic pump 2 in the stirring tank 3 through the above continuous demulsification method. To ensure sufficient collision between the modified magnetic particles (M-MMPs) and the droplets in the emulsion, the hydraulic residence time of the emulsion in the stirring tank 3 should be greater than 30 s, and the length of the stirring paddle blade is greater than 1 / 4 of the radius of the stirring tank 3.

[0082] To ensure that stirring does not cause further fragmentation of the droplets, the stirring speed should be controlled within 300 - 1000 rpm. During the pumping of the emulsion, to ensure a sufficient concentration of the modified magnetic particles (M-MMPs), the modified magnetic particles (M-MMPs) should be continuously added to the stirring tank 3 to ensure that the concentration of the modified magnetic particles (M-MMPs) is greater than 0.025 g / mL.

[0083] After being mixed with the modified magnetic particles, the emulsion enters the separation chambers 5-1 and 5-2, and rapid demulsification and dehydration of the emulsion are completed under the action of a magnetic field. To ensure sufficient magnetic field action, the surface magnetic field intensity of the electromagnets 4-1 and 4-2 is above 400 Gs, the height of the separation chambers 5-1 and 5-2 should be less than 5 cm, and the hydraulic retention time of the emulsion in the separation chambers 5-1 and 5-2 is greater than 30 s. After magnetic separation, the magnetic particles are deposited at the bottom of the funnels of the separation chambers 5-1 and 5-2, the separated water is discharged into the water collection tank 8 through the pipeline at the lower side of the separation chambers 5-1 and 5-2, and the separated oil is discharged into the oil collection tank 7 through the pipeline at the upper side.

[0084] Judging from the test results, compared with magnetic oscillation enhancement, while enhancing the collision and capture of magnetic particles and droplets through turbulence, the problem of magnetic particle adhesion is solved, which helps to achieve continuous demulsification. Moreover, it can demulsify and dehydrate the produced liquid of shale oil extracted by hydraulic fracturing with a high degree of emulsification. The produced liquid of shale oil is a water-in-crude oil emulsion with a large amount of surface active substances, a high strength of the oil-water interface film, and the asphaltenes and resins in the crude oil will contaminate the traditional magnetic nanoparticles, resulting in a decrease in separation efficiency. Through the modified magnetic particles and the method based on turbulent dispersion in the embodiments of the present application, the shale oil can be well demulsified and its separation efficiency can be improved.

[0085] The device in the above-mentioned continuous demulsification method of magnetic particles based on turbulent dispersion includes an emulsion tank, a peristaltic pump, a stirring tank, an electromagnet, a separation chamber, a magnetic particle collection tank, an oil collection tank and a water collection tank. The design of the stirring tank ensures sufficient collision between the magnetic particles and the droplets in the emulsion, and the design of the separation chamber ensures sufficient magnetic field action to achieve rapid demulsification and dehydration of the emulsion. Moreover, the device can operate continuously for a long time without frequent cleaning of the magnetic particles. It can achieve continuous and long-term use and improve the working efficiency of continuous demulsification.

[0086] Furthermore, the separation efficiency of the demulsification method using modified magnetic particles through turbulent dispersion is tested.

[0087] As Figure 8 shown, due to the relatively large size of the Fe 3 O 4 particles, their Brownian motion is relatively weak, and the collision probability is mainly affected by hydrodynamic effects.

[0088] Under the condition of 60 °C and with the dosage of the modified magnetic particles m = 3.33 g / mL, the emulsion prepared at a shear rotation speed ω = 2000 rpm is separated. The variation of the separation efficiency with the number of shaking / magnetic adsorption times is as Figure 8As shown. The separation efficiency of the shale oil emulsion was only 30% after the first shaking / magnetic adsorption, while it reached 77% after the fourth shaking / magnetic adsorption. Multiple shaking / magnetic adsorption can significantly improve the separation efficiency. The relationship between the separation efficiency and shaking / magnetic adsorption indicates that Fe 3 O 4 The collision and capture of particles and water droplets are the key factors for oil-water separation. Both the shaking-generated turbulent flow field and magnetic oscillation improve the separation efficiency by enhancing the collision between particles and water droplets, but using the turbulent flow field avoids the problem of Fe 3 O 4 particle adhesion to the wall surface.

[0089] The hydrophilic surface of the modified magnetic particles is beneficial to the spreading of water droplets in oil on the particle surface and can promote the coalescence of small water droplets; while the lipophilic particle surface will cause the water droplets to bounce off or form point adhesion after colliding with the particles, and it has little promoting effect on the coalescence of small water droplets. As the diameter of the water droplets increases, the capture process of the modified magnetic particles on the water droplets gradually becomes the adsorption process of Fe 3 O 4 particles at the water-oil interface. At this time, the surface hydrophilicity-hydrophobicity mainly affects the embedding depth of the particles at the oil-water interface and has little effect on the aggregation and coalescence of droplets under the action of the magnetic field. Therefore, when the average particle size of the emulsion is larger, the separation efficiencies of MMPs and M-MMPs are basically the same, while when the average particle size of the emulsion is smaller, M-MMPs show higher separation efficiency.

[0090] In the embodiments of the present application, those not specified in specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes Scheme A, or Scheme B, or the scheme where A and B are satisfied simultaneously.

[0091] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can achieve it. When the combination of technical solutions appears contradictory or impossible to achieve, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0092] In the above embodiments, the descriptions of the various embodiments each have their own emphasis. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0093] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and the embodiments are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0094] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A method for preparing modified magnetic particles, characterized in that: The method comprises: S101, adding vinyltrimethoxysilane to anhydrous ethanol and stirring to obtain solution A; S102, adding perfluorooctanoic acid and sodium hydroxide into anhydrous ethanol and stirring to obtain solution B; S103, adding magnetic particles to the mixed solution of the solution A and the solution B, moving to a reaction kettle, placing at 70-90° C. and keeping warm for 0.5-2 h, cooling, and drying to obtain the modified magnetic particles; wherein the magnetic particles are magnetic micron ferrosoferric oxide particles.

2. The method according to claim 1, characterized in that The mesh size of the magnetic ferroferric oxide particles is 300-800 meshes.

3. The method according to claim 1, characterized in that: The volume ratio of the vinyltrimethoxysilane to anhydrous ethanol is 0.1:(10-20); And / or, the mass volume ratio of perfluorooctanoic acid, sodium hydroxide and anhydrous ethanol is 1 g: (0.1-0.15) g: (20-35) mL.

4. A modified magnetic particle, characterized in that: The modified magnetic particles are prepared by the method according to any one of claims 1 to 3.

5. The modified magnetic particle according to claim 4, characterized in that The contact angle of the modified magnetic particles to oil is above 140°; The contact angle of the modified magnetic particles to water is below 20°.

6. The modified magnetic particle according to claim 4, characterized in that The separation temperature of the modified magnetic particles for separating the water-in-oil emulsion is 20-60°C.

7. A method for continuous demulsification based on turbulent dispersion, characterized in that: The modified magnetic particles prepared by the method according to any one of claims 1 to 3, and / or the modified magnetic particles according to any one of claims 4 to 6, are used in continuous demulsification based on turbulent dispersion, comprising: S201, using a peristaltic pump (2) to pump the emulsion into a stirring tank (3) to mix with the modified magnetic particles, and the hydraulic retention time in the stirring tank (3) is greater than or equal to 30 seconds; S202, controlling the surface magnetic field intensity of the electromagnet (4-1, 4-2) to be above 400 Gs, the height of the separation chamber (5-1, 5-2) to be less than 5 cm, and the hydraulic retention time of the emulsion in the separation chamber (5-1, 5-2) to be greater than 30 s; S203, after separation by the magnetic field, the modified magnetic particles are deposited at the bottom of the funnel of the separation chamber (5-1, 5-2), the separated water is discharged from the pipeline at the lower side of the separation chamber into the water collection tank (8), and the separated oil is discharged from the pipeline at the upper side into the oil collection tank (7).

8. The method according to claim 7, characterized in that The length of the stirring paddle blade in the stirring tank (3) is greater than 1 / 4 of the radius of the stirring tank (3).

9. The method according to claim 7, characterized in that: The stirring speed of the stirring tank (3) is controlled within a range of 300-1000 rpm to ensure that stirring does not lead to further breakup of the droplets.

10. The method according to claim 7, characterized in that In the stirring tank (3), the concentration of the modified magnetic particles is greater than 0.025 g / mL.

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