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

Abstract

The invention provides a preparation method of modified magnetic particles and a continuous demulsification method of the modified magnetic particles, and the preparation method comprises the following steps: adding vinyl trimethoxy silane into absolute ethyl alcohol, and stirring to obtain a solution A; adding perfluorooctanoic acid and sodium hydroxide into absolute ethyl alcohol, and stirring to obtain a solution B; adding magnetic particles into a mixed solution of the solution A and the solution B, transferring into a reaction kettle, placing at 80-90 DEG C, preserving heat for 0.5-2 hours, cooling and drying to obtain modified magnetic particles; according to a method for applying the modified magnetic particles to turbulent dispersion continuous demulsification, an emulsion is pumped into a stirring tank through a peristaltic pump to be mixed with M-MMPs, and the hydraulic retention time in the stirring tank is longer than or equal to 30 s; the surface magnetic field intensity of the electromagnet is controlled to be 400 Gs or above, the height of the separation chamber is smaller than 5 cm, the hydraulic retention time of the emulsion in the separation chamber is longer than 30 s, and separated oil and water are collected; and the modified magnetic particles cannot be gradually adhered to the wall surface of the separation chamber, so that the optimal separation effect is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic particle demulsification, and in particular to a method for preparing 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 the bottle test and have shown recyclable and pollution-free environmental characteristics, but the high preparation cost and low recycling times of modified MNPs limit their industrial application in the field of oil-water separation. In comparison, the cost of MNPs for treating oil-in-water emulsions (O / W) is 7.8 to 34.4 times that of magnetic microparticles (MMPs).

[0003] On the one hand, MMPs have a high price advantage over MNPs; on the other hand, MMPs have lower surface energy, are more affected by turbulent dispersion, and are easier to disperse and recover in emulsions. Therefore, the particle agglomeration effect caused by particle surface contamination can be weakened, and increasing the particle size of magnetic particles is an effective way to achieve industrial application of magnetic particles in the field of oil-water separation.

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

[0005] The embodiments of the present application provide a method for preparing modified magnetic particles, as well as a continuous demulsification method for modified magnetic particles based on turbulent dispersion and its application, in order to solve the technical problems in the prior art that the separation efficiency of magnetic particles for shale oil emulsion 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 separation efficiency.

[0006] In a first aspect, an embodiment of the present application provides a method for preparing modified magnetic particles, the method comprising:

[0007] S101, adding vinyltrimethoxysilane (VTMO, chemically pure) to anhydrous ethanol (analytical pure) and stirring to obtain solution A;

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

[0009] S103, adding magnetic particles to the mixed solution of the solution A and the solution B, moving to a reaction kettle, placing at 80-90° C. and keeping warm for 0.5-2 h, cooling, and drying to obtain the modified magnetic particles (M-MMPs).

[0010] In an optional embodiment, the magnetic particles are magnetic micronized ferroferric oxide particles (Fe 3 O 4 ).

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

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

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

[0014] In an optional embodiment, the contact angle of the modified magnetic particles to oil is above 140°;

[0015] In an optional embodiment, the separation temperature of the modified magnetic particles 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, wherein the modified magnetic particles prepared by the method of any one of the embodiments of the first aspect of the present application, and / or the modified magnetic particles of any one of the embodiments of the second aspect of the present application are used in continuous demulsification based on turbulent dispersion, comprising:

[0017] S201, using a peristaltic pump to pump the emulsion into a stirring tank to mix with the modified magnetic particles, and the hydraulic retention time in the stirring tank is greater than or equal to 30 seconds;

[0018] S202, controlling the surface magnetic field strength of the electromagnet to be above 400 Gs, the height of the separation chamber to be less than 5 cm, and the hydraulic retention time of the emulsion in the separation chamber to be greater than 30 s;

[0019] S203, after separation by the magnetic field, the modified magnetic particles are deposited at the bottom of the separation chamber funnel, the separated water is discharged into the water collection tank from the pipeline below the side of the separation chamber, and the separated oil is discharged into the oil collection tank from the pipeline above the side.

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

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

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

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

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

[0025] 2. After separation, the oil and water valves of the separation chamber and the electromagnet at the bottom of the separation chamber are closed, and the pipeline valve at the bottom of the separation chamber is opened to discharge the magnetic particles into the magnetic particle collection tank, which can be directly added to the stirring tank for reuse without any cleaning. A stirring tank with two separation chambers alternately discharges magnetic particles and performs magnetic field demulsification, which can achieve long-term continuous demulsification of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] Figure 1 A process flow chart of a method for preparing modified magnetic particles provided in an embodiment of the present application;

[0028] Figure 2 The wettability of the magnetic particle sample provided in the examples of the present application with water and white oil (a) and the wettability of the modified magnetic particle sample with water and white oil (b);

[0029] Figure 3 The contact angle between the magnetic particle sample provided in the embodiment of the present application and white oil (a) and the contact angle between the modified magnetic particle sample and water droplet (b);

[0030] Figure 4 A test curve diagram of the effect of shear speed on the separation efficiency of magnetic particles (MMPs) and modified magnetic particles (M-MMPs) provided in the examples of the present application;

[0031] Figure 5 A test curve of the separation efficiency of the modified magnetic particles (M-MMPs) affected by temperature provided in the examples of the present application;

[0032] Figure 6 A flow chart of a method for continuous demulsification based on modified magnetic particles provided in an embodiment of the present application;

[0033] Figure 7 A schematic diagram of an experimental device for a continuous demulsification method based on modified magnetic particles provided in an embodiment of the present application;

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

[0035] Description of reference numerals:

[0036] 1————emulsion tank;

[0037] 2————Peristaltic pump;

[0038] 3————Mixing tank;

[0039] 4-1, 4-2————electromagnet;

[0040] 5-1, 5-2————Separation chamber;

[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] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope 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 DESCRIPTION

[0047] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0048] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following 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 in conjunction with the accompanying drawings.

[0049] Example

[0050] A method for preparing modified magnetic particles, the preparation method comprising the following steps:

[0051] 100 μL of VTMO was added to 15 mL of anhydrous ethanol and stirred for 0.5 h. The solution was named solution A.

[0052] 0.5 g PFOA and 0.05 g NaOH were placed in 15 mL anhydrous ethanol and stirred for 0.5 h. The solution was named solution B.

[0053] Solution A was slowly added dropwise to solution B and stirred for 0.5 h to obtain a mixed solution C. 3 O 4 The particles and the mixed solution C were placed in a hydrothermal reactor, and the hydrothermal reactor was placed in an oven and kept at 80°C for 1 hour. After cooling, the Fe 3 O 4 The particles are dried to obtain M-MMPs.

[0054] Comparative Example

[0055] Fe purchased from the market, with the same mesh size as in the above example 3 O 4 The particles, after drying, obtain MMPs.

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

[0057] The white oil (mineral oil) used in this application was purchased from Mojiezuo Petrochemical (Shanghai) Co., Ltd. Wahaha purified water was purchased from Wahaha Limited Group Company.

[0058] The shale oil produced fluid was obtained from Dongxin Oilfield, Shengli Oilfield, Jiyang, China. The surface tension of shale oil and produced water in the shale oil produced fluid was determined by the hanging drop method, and the liquid viscosity was measured by a rotational viscometer (NDJ-8s). The liquid physical properties are shown in Table 1.

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

[0060]

[0061] The following performance tests were performed on the M-MMPs prepared in the above examples and the MMPs prepared in the comparative examples.

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

[0063] like Figure 2 It can be observed that for MMPs, both oil droplets and water droplets show good wettability to the MMPs sample; while for M-MMPs, water droplets can still penetrate into the M-MMPs sample, while oil droplets can hardly wet the M-MMPs sample. 3 O 4 The particles change from hydrophilic to hydrophilic / oleophobic properties.

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

[0065] like Figure 3 As shown in the figure, after the oil droplet stabilizes on the M-MMPs sample, the average contact angle can reach 141.21°. After the water droplet contacts the M-MMPs sample, it gradually and completely wets the M-MMPs sample. Further tests show that the average contact angle of the M-MMPs sample after 1.5s of contact is 20.34°, which further shows that the modified Fe 3 O 4 The particles (M-MMPs) change from hydrophilic / oleophobic properties to hydrophilic / oleophobic properties, and M-MMPs have excellent hydrophilic and oleophobic properties.

[0066] 3. Dehydration efficiency performance test.

[0067] At 60°C, MMPs and M-MMPs were added at a dosage of m=3.33 g / mL, and the prepared shale oil emulsion was separated using MMPs and M-MMPs at different shear speeds.

[0068] Test results such as Figure 4 As shown in the figure, through the curve of separation efficiency E changing with shear speed ω, it can be seen that with the increase of shear speed, the separation efficiency of MMPs and M-MMPs decreases, but the separation efficiency of M-MMPs decreases to a smaller extent, indicating that M-MMPs has more stable separation performance, and its separation effect is less affected by the speed.

[0069] Furthermore, through testing, it can be seen that when the shear speed ω<2000rpm, the separation efficiency of MMPs and M-MMPs is almost the same; after continuing to increase the shear speed, when the shear speed ω≥3000rpm, M-MMPs exhibits better separation performance than MMPs; and when the shear speed ω=5000rpm, 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≥3000rpm, and is less affected by the shear speed.

[0070] 4. The influence of temperature on separation efficiency.

[0071] Generally speaking, for magnetic particles, increasing 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 interface 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 low freezing point temperatures such as shale oil, low-temperature demulsification is the key to reducing energy consumption. Since the freezing point of the shale oil used is 28°C and the fluidity is poor at around 35°C, a demulsification test at 40-60°C was conducted. First, the M-MMPs with a test dosage of m=3.33g / mL was added, and the shear speed ω=2000rpm was set. Demulsification was performed at 40°C, 45°C, 50°C, 55°C, and 60°C, respectively. The test results are shown in Figure 2. Figure 5 shown.

[0073] like Figure 5 As shown in the figure, from the separation efficiency line graph of M-MMPs at different temperatures, it can be seen that the separation efficiency changes linearly with temperature, with the lowest separation efficiency being 60% at 40°C and the highest separation efficiency being 77% at 60°C. The separation efficiency is less affected by temperature, and a separation efficiency of 60% can be achieved at 10°C above the freezing point of shale oil.

[0074] 5. Test of circulation separation performance.

[0075] At 60°C, the dosage of M-MMPs was m = 3.33 g / mL, and the emulsion prepared at a shear speed of 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 of 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%. M-MMPs demonstrates excellent recycling capabilities.

[0077] In view of the small size of M-MMPs and MMPs, they will show certain Brownian motion characteristics in the liquid. The collision between magnetic particles and water droplets is affected by the dispersion of magnetic particles and the double electric layer of the oil-water interface. In order to minimize the above influences during the demulsification process of the magnetic particles of the present application, the demulsification is performed more excellently. The present application also proposes a method for continuous demulsification of modified magnetic particles based on turbulent dispersion, such as Figure 6 As shown, the method includes:

[0078] The peristaltic pump 2 pumps the emulsion into the 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.

[0079] The surface magnetic field strength of the electromagnets 4-1 and 4-2 is controlled to be above 400 Gs, the height of the separation chambers 5-1 and 5-2 is 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.

[0080] After magnetic field 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 from the pipeline below the side of the separation chamber into the water collection tank 8, and the separated oil is discharged from the pipeline above the side into the oil collection tank 7.

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

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

[0083] After mixing with the modified magnetic particles, the emulsion enters the separation chambers 5-1 and 5-2, and the emulsion is quickly demulsified and dehydrated under the action of the magnetic field. To ensure sufficient magnetic field effect, the surface magnetic field strength of the electromagnets 4-1 and 4-2 is above 400Gs, the height of the separation chambers 5-1 and 5-2 should be less than 5cm, and the hydraulic retention time of the emulsion in the separation chambers 5-1 and 5-2 is greater than 30s. After magnetic field separation, the magnetic particles are deposited at the bottom of the funnel of the separation chambers 5-1 and 5-2, and the separated water is discharged from the pipeline below the side of the separation chambers 5-1 and 5-2 into the water collection tank 8, and the separated oil is discharged from the pipeline above the side into the oil collection tank 7.

[0084] From the test results, compared with magnetic oscillation enhancement, turbulence can be used to enhance the collision and capture of magnetic particles and droplets while solving the adhesion problem of magnetic particles, which is helpful to achieve continuous demulsification. It can also be used to demulsify and dehydrate shale oil produced fluid with high emulsification degree and produced by hydraulic fracturing. Shale oil produced fluid is a crude oil-water emulsion with many surfactants and high oil-water interface film strength. In addition, asphaltene and colloid in crude oil will contaminate traditional magnetic nanoparticles, resulting in reduced separation efficiency. Through the modified magnetic particles in the embodiments of this application and the method based on turbulent dispersion, shale oil can be well demulsified and its separation efficiency can be improved.

[0085] The device in the above-mentioned magnetic particle continuous demulsification method 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, wherein 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 effect, so as to achieve rapid demulsification and dehydration of the emulsion, and the device can be continuously operated 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] In a further step, the separation efficiency of the demulsification method using modified magnetic particles through turbulent dispersion was tested.

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

[0088] At 60°C, the modified magnetic particles were added at a dosage of m = 3.33 g / mL, and the emulsion prepared at a shear speed of ω = 2000 rpm was separated. The separation efficiency changes with the shaking / magnetic adsorption times as shown in Figure 8As shown in the figure. After the first shaking / magnetic adsorption, the separation efficiency of shale oil emulsion was only 30%, while the separation efficiency reached 77% after the fourth shaking / magnetic adsorption. Multiple shaking / magnetic adsorption can significantly improve the separation efficiency. The relationship between separation efficiency and shaking / magnetic adsorption shows that Fe 3 O 4 The collision and capture of particles and water droplets are key factors in oil-water separation. Both shaking to generate turbulent flow fields and magnetic oscillations improve separation efficiency by strengthening the collision between particles and water droplets, but using turbulent flow fields avoids Fe 3 O 4 The problem of particles sticking to the wall.

[0089] The hydrophilic surface of the modified magnetic particles is conducive to the spreading of water droplets in the oil on the particle surface, which can promote the coalescence of small water droplets; while the oleophilic surface of the particles will cause the water droplets to bounce off or form point adhesion after collision with the particles, which has almost no effect on promoting 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 changes to Fe 3 O 4 During the adsorption process of particles at the water droplet interface, the surface hydrophilicity and hydrophobicity mainly affect the embedding depth of particles at the oil-water interface, and have 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 large, the separation efficiency of MMPs and M-MMPs is basically the same, while when the average particle size of the emulsion is small, M-MMPs shows a higher separation efficiency.

[0090] In the examples of the present application, if the specific conditions are not specified, the conditions are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, and "A and / or B" is taken as an example, including scheme A, or scheme B, or schemes that A and B meet simultaneously.

[0091] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, 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 ordinary technicians in this field without creative work are within the scope of protection of this application.

[0092] In the above embodiments, the description of each embodiment has its own emphasis. For the part not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0094] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only 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.

2. The method according to claim 1, characterized in that The magnetic particles are magnetic micronized ferroferric oxide particles; And / or, 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 1g: (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 below the side of the separation chamber into the water collection tank (8), and the separated oil is discharged from the pipeline above the 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 the range of 300 to 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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