In-line cone oil-water-sand three-phase separation device coupled with electric field and rotational flow field

Abstract

This invention provides a three-phase oil-water-sand separation device with an inner cone and a coupled electric field-swirling field. It mainly consists of a cylinder, swirling guide vanes, and a separation settling cone section. The separation settling cone section includes an inner mesh, an outer mesh, and an inner cone. A multi-directional radial electric field is applied inside the cone section, so that the crude oil produced fluid undergoes both electro-aggregation and centrifugal separation processes after entering the swirling structure. The inner cone enriches the unseparated oil droplets at the tip of the cone section and lifts the oil phase, improving the oil-water separation efficiency. A conical conductive filter screen is fitted inside the dual-outlet cylinder, so that the water phase is filtered by the filter screen and discharged from the side outlet, while the sand and gravel are discharged from the underflow outlet.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical machinery and crude oil dehydration equipment, specifically relating to an internal cone oil-water-sand three-phase separation device with coupled electric field and swirling flow field. Background Technology

[0002] The exploitation of low-permeability and ultra-low-permeability reservoirs is an important source of increased oil production. To address the complex seepage mechanisms and poor reservoir properties in these reservoirs, nano-displacement technology is widely used to enhance oil recovery. This technology offers advantages such as increasing the pressure separating oil droplets from the rock, altering formation wettability, low cost, and strong adaptability.

[0003] However, due to the presence of nanoparticles, crude oil produced fluid (nano-driven produced fluid) exhibits stable Pickering emulsion characteristics, which makes deep dehydration difficult, is not conducive to safe gathering and transportation, and can cause problems such as corrosion of refining equipment, poor oil quality, and high energy consumption.

[0004] Conventional demulsification methods mainly include centrifugal demulsification, electrostatic demulsification, chemical demulsification, and ultrasonic demulsification. However, single demulsification technologies are insufficient for achieving efficient dehydration of nano-flooded produced fluids, and the underflow from ordinary hydrocyclone dewatering devices still contains a large amount of oil and sand, increasing the difficulty of wastewater treatment. Therefore, it is necessary to develop a dewatering device that couples multiple demulsification technologies to simultaneously remove sand from the wastewater while ensuring efficient dehydration of nano-flooded produced fluids, ultimately achieving efficient separation of the oil-water-sand three phases in a single process. Summary of the Invention

[0005] Based on the above-mentioned technological status, the present invention provides a three-phase separation device for oil-water-sand with an inner cone and a coupled electric field-swirling field. The separation sedimentation cone section includes an inner net, an outer net, and an inner cone. A multi-directional radial electric field is applied inside the cone section, so that the nano-driven produced fluid enters the swirling structure and simultaneously undergoes electro-aggregation and centrifugal separation processes. The inner cone enables the unseparated oil droplets in the cone section to accumulate at the tip, while simultaneously lifting the oil phase, thereby improving the oil-water separation efficiency.

[0006] The technical solution adopted in this invention is as follows: A three-phase separation device for oil-water-sand with an inner cone and coupled electric field-swirling field includes a shell of a cyclone separator structure composed of multiple cylindrical sections, swirling guide vanes, an inner mesh, an outer mesh, an inner cone, and clamps. The first cylindrical section has a side inlet, which can be a tangential inlet or a direct current inlet. The fourth cylindrical section has a side water phase outlet, and the bottom of the fourth cylindrical section is a sand outlet. The middle cylindrical sections are all cylindrical, with flanges at both ends. The swirling guide vanes have multiple (e.g., five) helical blades for stabilizing and enhancing the swirling flow, and a shaft is formed at the center of the swirling guide vanes. The through-hole serves as an overflow channel to discharge the concentrated oil phase. It is suspended in the first section of the cylinder using a flange. Reinforcing ribs are installed at the connection between the swirl guide vanes and the flange to strengthen the structure and prevent breakage. The inner mesh has a flanged annular disc for connection to the cylinder, and a wiring connection piece is installed outside the disc for grounding. The outer mesh also has a flanged disc for connection to the cylinder, and a connection piece is installed outside the disc for connection to the power supply. The inner cone is made of copper, with a slender cone head and a columnar tail, and deep holes are drilled inside to reduce its weight. The clamp is used to hold the inner cone and adjust its height.

[0007] Furthermore, in the multi-section cylinder, to ensure the bottom of the outer mesh is fixed and to achieve stable operation of the equipment, the fourth cylinder is equipped with a retaining ring. The retaining ring is a cylindrical ring that can quickly and efficiently limit the vibration range of the bottom of the outer mesh.

[0008] Furthermore, in the multi-section cylinder, the second cylinder can be selected with different lengths according to actual engineering needs to achieve higher separation efficiency under the current working conditions.

[0009] Furthermore, the bottom overflow port of the swirl guide vane is provided with a frustoconical overflow pipe structure. This structure helps to improve the oil phase separation efficiency, reduce the probability of "coarse flow" in the overall equipment, and facilitates the fastening installation of the inner mesh and the swirl guide vane. The outlet helix wrap angle of the swirl channel is 10°-50°, preferably 20°.

[0010] Furthermore, both the inner and outer meshes are conical, with the cone angle limited to between 3° and 20°, preferably 6°, and their surfaces are coated with epoxy resin to meet the equipment filter's performance requirements for insulation, wear resistance, and high-temperature resistance. Considering the requirements of the inner and outer meshes for conductivity, thermal conductivity, corrosion resistance, strength, and toughness, copper or aluminum alloys are preferred as the manufacturing materials.

[0011] Furthermore, both the inner and outer meshes are equipped with flange rings to connect to the cylinder. Since the inner and outer meshes require grounding and power connection, this design avoids drilling holes in the cylinder, thus meeting the equipment's high sealing requirements.

[0012] Furthermore, the outer mesh is not perforated as a whole, but rather perforated to a certain height to minimize fluid kinetic energy loss in the unperforated section, efficiently concentrating the oil phase towards the center and the water phase towards the periphery, while simultaneously achieving rapid filtration of the water phase in the perforated section below. Regarding the aperture size, the outer mesh aperture must accommodate efficient filtration of the water phase while allowing most sand and gravel to be discharged from the bottom outlet of the outer mesh.

[0013] Furthermore, the inner cone works in conjunction with the clamp and is secured via screw holes on the clamp, allowing adjustment of the inner cone's depth into the device. Simultaneously, the ground wire is connected to the inner cone via a fastening screw, grounding the inner cone and creating a non-uniform electric field within the cone section of the device, thus enhancing the device's separation efficiency.

[0014] The beneficial effects of this invention are:

[0015] 1. This invention couples the hydrocyclone structure and the electrode structure, and utilizes the electrical properties and density differences between oil and water to apply a high-voltage electric field to the internal flow field of the hydrocyclone, thereby synergistically enhancing oil-water separation.

[0016] 2. This invention selects a swirl guide vane with an outlet wrap angle of 20° and limits the cone angles of the inner and outer meshes to 6°. This can better meet the condition that the particles completely follow the fluid movement, so as to avoid the water droplet breakage caused by excessive turbulence intensity at the outlet of the swirl guide vane and suppress the water droplet aggregation effect.

[0017] 3. This invention proposes the concept of an inner cone, which enables oil droplets in the unseparated oil-water mixture in the outer network to accumulate at the tip of the inner cone. The inner cone also has the function of lifting the accumulated oil droplets upwards, and the cylindrical section at the bottom of the inner cone has the function of stabilizing the flow field and reducing turbulence.

[0018] 4. This invention connects the external network to the power supply and the internal network and the inner cone to the ground. The internal separation and settling cone section forms a multi-angle radial electric field, which causes small water droplets in the crude oil produced to quickly aggregate, thereby enhancing the oil-water separation performance of the hydrocyclone.

[0019] 5. All parts of the invention are detachable, which facilitates the cleaning and replacement of parts in the later stages, making the equipment adaptable to various working conditions.

[0020] 6. The device of the present invention has a simple and stable structure, no moving parts, high operational reliability, and low maintenance cost. At the same time, the present invention can greatly reduce the amount of chemical reagents used, and is an environmentally friendly device.

[0021] 7. The invention has a compact overall design, the column section cylinder can be freely replaced with different lengths, and the bottom inner cone can be adjusted to extend to different depths, so that the invention can adapt to different moisture content conditions and meet the current social requirements for equipment with a wide range of applications.

[0022] 8. This equipment integrates a liquid cyclone separation system, an electro-dehydration separation system, and a filtration separation system. It is also equipped with an inner cone and segmented perforated cone sections, which can significantly improve the oil-water separation efficiency and achieve a single-process oil-water-sand three-phase separation effect. While reducing the energy consumption generated in the oil-water separation process, it can also reduce waste oil discharge and the waste of potential energy in residual oil, thus taking into account both "energy saving" and "emission reduction". Attached Figure Description

[0023] Figure 1 This is a structural diagram of the outer contour of the separation device of the present invention;

[0024] Figure 2 This is a half-sectional view of the separation device of the present invention;

[0025] Figure 3 This is a half-sectional view of the first-stage cylinder of the separation device of the present invention;

[0026] Figure 4 This is a half-sectional view of the second cylinder of the separation device of the present invention;

[0027] Figure 5 This is a half-sectional view of the third cylinder of the separation device of the present invention;

[0028] Figure 6 This is an isometric view of the fourth cylinder of the separation device of the present invention;

[0029] Figure 7 This is a half-sectional view of the fourth cylinder of the separation device of the present invention;

[0030] Figure 8 This is an isometric view of the cyclone guide vanes of the separation device of the present invention;

[0031] Figure 9 This is a front view of the cyclone guide vanes of the separation device of the present invention;

[0032] Figure 10 This is a schematic diagram of the internal network structure of the separation device of the present invention;

[0033] Figure 11 This is a cross-sectional view of the internal network installation method of the separation device of the present invention;

[0034] Figure 12 This is a schematic diagram of the external network structure of the separation device of the present invention;

[0035] Figure 13 This is a cross-sectional view of the external network installation method of the separation device of the present invention;

[0036] Figure 14 This is a schematic diagram of the inner cone structure of the separation device of the present invention;

[0037] Figure 15 This is an isometric view of the clamps of the separation device of the present invention;

[0038] In the diagram: 1. First-stage cylinder, 2. Second-stage cylinder, 3. Third-stage cylinder, 4. Fourth-stage cylinder, 5. Swirl guide vane, 6. Inner mesh, 7. Outer mesh, 8. Inner cone, 9. Clamp, 10. Stepped surface, 11. Large-diameter section, 12. Small-diameter section, 13. Snap ring, 14. Central column, 15. Swirl-generating guide vane, 16. Cover plate, 17. Conical frustum, 18. Conical cylinder, 19. Flange ring, 20. Circuit connection piece. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are for simplification and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Figure 1 This is a structural diagram of the outer contour of the present invention. Figure 2 This is a half-sectional view of the separation device of the present invention, combined with... Figure 1 and Figure 2 It can be understood that the oil-water-sand three-phase separation device with an inner cone and coupled electric field-swirling field of the present invention is a vertical cylindrical structure. For ease of assembly of the components, it includes, from top to bottom, a first-stage cylinder 1, a second cylinder 2, a third cylinder 3, and a fourth cylinder 4, which are fixedly connected in sequence. Inside the separation device, from top to bottom, are swirling guide vanes 5, an inner mesh 6, an outer mesh 7, and an inner cone 8. See details below. Figure 3-7 The upper and lower ends of the four-stage cylinder are designed with flange rings. The upper and lower positions of the four-stage cylinder are fixed by means of bolt flange connection. The flange connection of the corresponding size enhances the overall structural strength of the equipment and improves the stability of equipment operation. In addition, the flange ring end face between adjacent cylinders is convenient for clamping and installing internal components, avoiding drilling installation of the cylinder.

[0043] Figure 3 This is a half-sectional view of the first-stage cylinder of the separation device of the present invention. An inlet pipe is provided on the side of the first-stage cylinder 1 as an inlet channel for crude oil produced fluid. Figure 4 This is a half-sectional view of the second cylinder of the separation device of the present invention. Figure 5 This is a half-sectional view of the third cylinder of the separation device of the present invention. Both the second cylinder 2 and the third cylinder 3 are cylindrical shells with flange rings at the upper and lower ends. The difference is that the height of the second cylinder 2 is less than the height of the third cylinder 3. The second cylinder 2 is mainly used to facilitate the installation of the inner net 6, while the third cylinder 3 is used to install the outer net 7. Figure 6 This is an isometric view of the fourth cylinder of the separation device of the present invention. Figure 7 This is a half-sectional view of the fourth cylinder of the separation device of the present invention. The main body of the fourth cylinder 4 is stepped, and its interior is divided into an upper large-diameter section 11 and a lower small-diameter section 12 by a stepped surface 10. A water phase outlet pipe is provided on the side wall of the fourth cylinder 4, which is located above the stepped surface 10 and communicates with the large-diameter section 11. A circular retaining ring 13 protrudes upward on the stepped surface 10. The retaining ring 13 is a columnar ring, and the bottom of the outer mesh 7 is fitted into the inner circumference of the retaining ring 13, which can quickly and efficiently limit the vibration range of the bottom of the outer mesh 7 and ensure the stability of the outer mesh 7.

[0044] Observe from top to bottom Figure 2 A swirl guide vane 5 is installed inside the first-stage cylinder 1. The side of the swirl guide vane 5 contacts the inner wall of the first-stage cylinder 1, so that the swirl guide vane 5 forms a swirl-generating channel inside the first-stage cylinder. The crude oil produced fluid entering through the side inlet pipe of the first-stage cylinder 1 can flow completely in the spiral channel between the guide vanes, enhancing the equipment's flow stabilization and swirl-generating effect on the inlet fluid. An inner net 6 is clamped and installed between the first-stage cylinder 1 and the second cylinder 2, and the inner net 6 is nested with the lower part of the swirl guide vane 5. The upper part of the outer net 7 is clamped and fixed between the second cylinder 2 and the third cylinder 3, so that its main body is located in the internal space of the large-diameter section 11 of the third cylinder 3 and the second cylinder 4. The inner cone 8 extends upward from the bottom opening of the second cylinder 4 into the interior of the outer net 7. A clamp 9 is fixedly installed at the bottom of the second cylinder 4. The clamp 9 is used to adjust and fix the relative position of the inner cone 8 extending into the outer net 7.

[0045] See Figure 8 and Figure 9The figures are an isometric view and a front view of the swirl guide vane of the separation device of the present invention. The swirl guide vane 5 includes a central column 14 and a swirl-generating guide vane 15 integrally formed on the outer periphery of the central column 14. The upper part of the central column 14 has an integrally formed cover plate portion 16 for sealing the upper opening of the first-stage cylinder 1. The lower part of the central column 14 also has an integrally formed conical frustum 17, which achieves a close fit connection with the inner net 6, enhancing the stability of the inner net 6 during device operation. An overflow channel is opened at the central axis of the swirl-generating guide vane 15, which connects to the external space of the separation device from above, serving as a channel for the light phase of the swirl separation to flow out.

[0046] Figure 10 This is a schematic diagram of the internal network structure of the separation device of the present invention. Figure 11 This is a cross-sectional view of the installation method of the inner net of the separation device of the present invention. The inner net 6 consists of a flange ring 19 and a cone 18 fixed at the center of the flange ring 19 by a connecting arm. Small holes are evenly distributed on the cone 18. The flange ring 19 is clamped and fixed between the first stage cylinder 1 and the second cylinder 2, and the upper part of the cone 18 is nested on the cone-shaped frustum 17. At the same time, the cone 18 of the inner net 6 extends the cone-shaped frustum to achieve the blocking effect of sand and gravel in the overflow oil phase. A hollow flow channel is formed around the cone 18 on the flange ring 19. A line connecting piece 20 is integrally formed on the outer periphery of the flange ring 19. The line connecting piece 20 is used for grounding. By clamping the inner net 6 between the first stage cylinder 1 and the second cylinder 2, drilling holes in the cylinder is avoided, thus improving the overall sealing performance of the device.

[0047] Figure 12 This is a schematic diagram of the external network structure of the separation device of the present invention. Figure 13 This is a cross-sectional view of the installation method of the outer mesh of the separation device of the present invention. The outer mesh 7 also has a flange-shaped disc to connect the outer mesh 7 to the second cylinder 2 and the third cylinder 3. This design facilitates the installation and fixation of the outer mesh 7. At the same time, since the outer mesh 7 needs to be connected to a power source, this design avoids drilling holes in the cylinders, ensuring the overall sealing of the equipment. The power cord can be connected to the part of the flange-shaped disc located outside the clamping surface of the second cylinder 2 and the third cylinder 3. The outer mesh 7 is also cone-shaped as a whole, and its wall surface is also evenly distributed with small holes. In order to meet the requirements of the equipment for overflow efficiency, accelerate the overflow speed of the oil phase, and increase the overflow flow rate, the diameter of the small holes on the inner mesh 6 is larger than the diameter of the small holes on the outer mesh 7.

[0048] Furthermore, since external network 7 is larger than internal network 6, simply fixing it on one side at the top is insufficient to meet its stability requirements. See also... Figure 7A retaining ring 13 is provided at the diameter change point inside the fourth cylinder 4. The bottom of the outer net 7 is locked in the inner circumference of the retaining ring 13 and abuts against the stepped surface 10 of the fourth cylinder 4. The outer net 7 is also locked and fixed above to ensure the stability of the outer net 7.

[0049] like Figure 10 and Figure 12 Both the inner mesh 6 and the outer mesh 7 have connecting plates extending from both sides to facilitate the connection between the metal mesh and the wires, preventing short circuits and other accidents caused by contact between the wires and the medium. Both surfaces are coated with epoxy resin to meet the equipment filter's requirements for insulation, wear resistance, and high-temperature resistance. Considering the requirements for conductivity, thermal conductivity, corrosion resistance, strength, and toughness of the inner and outer meshes, copper and aluminum alloys are preferred as the manufacturing materials.

[0050] When the crude oil produced fluid is ejected from the swirl guide vane 5, it first stabilizes and swirls within the second cylinder 2, and then enters the conical section formed by the outer mesh 7. The wrap angle at the outlet of the swirl guide vane is preferably 20°. The cone angles of the inner mesh 6 and the outer mesh 7 can be set to be the same, between 3° and 20°, preferably in the conical section with a cone angle of 6°, to satisfy the condition that the particles completely follow the fluid movement, avoiding the breakage of water droplets due to excessive turbulence intensity at the outlet of the swirl guide vane, and inhibiting the water droplet aggregation effect. The charged outer mesh 7, together with the grounded inner mesh 6 and the inner cone 8, constitute a multi-directional radiating electric field, causing the water droplets in the produced fluid to elongate and oscillate. The elongation of the water droplets causes the interface film to deform and rupture, enhancing the aggregation effect and strengthening the electro-aggregation process of small water droplets. Since the oil-water mixture after separation is still subject to centrifugal sedimentation, due to the difference in density, under the contraction and pressure of the outer mixture, the inner oil phase has to change direction and move upward, forming an inner swirl, which flows out of the equipment through the overflow channel in the center of the upper swirl guide vane 5.

[0051] When the produced crude oil enters the conical section, the unperforated section above the outer mesh 7 reduces fluid kinetic energy loss, efficiently concentrating the oil phase towards the center and the aqueous phase and water-based nanoparticles towards the periphery. In the perforated section below, the aqueous phase and water-based nanoparticles permeate through the mesh into the vortex chamber between the outer mesh 7 and the third cylinder 3, ultimately exiting at the side aqueous phase outlet of the lower fourth cylinder 4. Due to the presence of the perforated section below, most of the sand and gravel can only be discharged along with the waste fluid through the underflow outlet below the fourth cylinder 4, achieving the concentration of sand and gravel in the produced crude oil.

[0052] Figure 14 This is a schematic diagram of the inner cone structure of the separation device of the present invention. Figure 15 This is an isometric view of the clamp of the separation device of the present invention. The inner cone 8 consists of an upper cone and a lower cylinder. The cone extends into the outer mesh 7, and the cylinder is inserted into the clamp 9. The clamp 9 fixes the position of the inner cone 8. Figure 15Multiple pin holes or threaded holes can be distributed along the axial direction on the fixture 9. The fixture is positioned by pinning the inner cone 8 to the cylinder. Alternatively, the threaded hole is threaded with a bolt. Tightening the bolt inward causes its inner end to press against or loosen the cylinder of the inner cone 8, thereby fixing or adjusting the height position of the inner cone 8.

[0053] Combination Figure 2 The inner cone 8, extending into the outer mesh 7, can have its insertion height freely controlled by the clamp 9. Due to the presence of the inner cone 8, oil droplets in the unseparated oil-water mixture of the outer mesh 7 are enriched at the tip of the inner cone 8, improving the separation effect of the equipment. The inner cone 8 can also lift the accumulated oil droplets upwards, accelerating the discharge of the oil phase. The cylindrical section at the bottom of the inner cone can stabilize the flow field, reduce turbulence, and reduce splashing of waste liquid at the underflow outlet.

[0054] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions of the present invention, various modifications or variations of equivalent structures or equivalent processes that can be made by those skilled in the art without creative effort, or directly or indirectly applied to other related technical fields, are still within the scope of protection of the present invention.

Claims

1. A three-phase separation device for oil-water-sand with an internal cone and coupled electric field-swirling flow field, characterized in that, The device includes a vertical cylindrical structure, in which swirl guide vanes, an inner mesh, an outer mesh, and an inner cone are arranged sequentially from top to bottom inside the cylindrical structure. An inlet pipe is provided on the side of the cylindrical structure near the upper end. The swirl guide vanes form a swirl channel inside the cylindrical structure, and the axis of the swirl guide vanes forms an overflow channel that extends upward through the cylindrical structure. Both the inner and outer nets are conical. The upper end of the inner net is connected to the lower part of the swirl guide vane, and small holes are evenly distributed on the cone-shaped inner net that gradually tapers from top to bottom. The outer net is located below the inner net, and the cone-shaped outer net also gradually tapers from top to bottom. Small holes are evenly distributed on at least the lower half of the cone-shaped outer net. The inner cone extends upward from the bottom of the cylindrical structure into the interior of the outer mesh, with the cone angle of the inner cone pointing upward; The inner diameter of the cylindrical structure is reduced to a stepped surface near the lower end. The lower end of the cone of the outer mesh abuts against the stepped surface. A water phase outlet pipe is provided above the stepped surface of the cylindrical structure. The gap between the bottom opening of the cylindrical structure and the inner cone constitutes the underflow outlet. The inner mesh, outer mesh, and inner cone are all made of conductive materials, and the inner mesh and inner cone are grounded via a line, while the outer mesh is connected to a power source via a line.

2. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 1, characterized in that, The cylindrical structure includes a first-stage cylindrical body, a second-stage cylindrical body, a third-stage cylindrical body, and a fourth-stage cylindrical body, which are fixedly connected from top to bottom. Flange rings are provided at the upper and lower ends of the four-stage cylindrical bodies, and the upper and lower positions of the four-stage cylindrical bodies are fixedly connected by bolt flanges.

3. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 1 or 2, characterized in that, The swirl guide vane includes a central column and a swirl-generating guide vane integrally formed on the outer periphery of the central column. The upper part of the central column is integrally formed with a cover plate for sealing the upper opening of the first-stage cylinder. The lower part of the central column is also integrally formed with a conical frustum. The upper end of the inner mesh is nested on the conical frustum. The overflow channel is opened at the axis of the central column and axially passes through the central column.

4. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 2, characterized in that, The inner network consists of a flange ring and a cone fixed at the center of the flange ring by a connecting arm. Small holes are evenly distributed on the cone. The flange ring is clamped and fixed between the first-stage cylinder and the second-stage cylinder. A hollow flow channel is formed around the cone on the flange ring, and a circuit connecting piece is integrally formed on the outer periphery of the flange ring.

5. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 4, characterized in that, The outer mesh also includes a cone and a flange-shaped disc connected to the upper end of the cone. The flange-shaped disc is clamped and fixed between the second cylinder and the third cylinder. A circuit connection piece is also integrally formed on the outer periphery of the flange-shaped disc.

6. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 2, further characterized in that, The stepped surface is formed inside the fourth cylinder, dividing the fourth cylinder into an upper large-diameter section and a lower small-diameter section. The water phase outlet pipe is located in the large-diameter section. A circular retaining ring protrudes upward from the stepped surface, and the bottom of the cone of the outer mesh is fitted into the inner circumference of the retaining ring.

7. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 1, characterized in that, The inner mesh, outer mesh, and inner cone are made of copper or aluminum alloy.

8. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 2, characterized in that, The bottom end of the fourth cylinder is also fixedly connected to a clamp, which is used to fix and adjust the height position of the inner cone.

9. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 5, characterized in that, The outlet spiral wrap angle of the vortex channel is 10°-50°, and the cone angles of the inner and outer meshes are both between 3°-20°.

10. The three-phase oil-water-sand separation device with coupled electric field-swirling field according to claim 9, characterized in that, The outlet spiral wrap angle of the vortex channel is 20°, and the cone angles of both the inner and outer meshes are 6°.

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