Oil-water separation device and method using lipophilic packing for gravity separation

Abstract

The present application relates to the technical field of oil-water separation, and particularly relates to a kind of lipophilic filler gravity separation oil-water separation device and method, and the lipophilic filler gravity separation oil-water separation device includes multiple separation units, each separation unit includes central sleeve and settling cup;The central sleeve includes inner tube and outer tube, and the inner tube is formed between the outer tube and the outer tube Inner separation cavity, the outer tube is provided with first liquid inlet and oil outlet, and the inner tube is provided with second liquid inlet;The settling cup is coaxially arranged outside the outer tube, and the inside of the settling cup forms an outer separation cavity;Spiral separation cylinder is arranged in the inner separation cavity of at least one separation unit, and spiral blade is arranged on the outer wall of the spiral separation cylinder;First liquid inlet is used to guide the oil-water mixture after preliminary separation in the outer separation cavity to the spiral blade for secondary centrifugal separation;Oil outlet is used to return the oil after secondary separation to the outer separation cavity, and the second liquid inlet is used to discharge the water phase after secondary separation into the inner tube, which can improve the degree of oil-water separation.

Description

Technical Field

[0001] This invention relates to the field of oil-water separation technology, and in particular to an oil-water separation device and method using oleophilic packing gravity separation. Background Technology

[0002] With the continuous increase in the water cut of produced fluids from oil wells in domestic oilfields, the scale of oily wastewater treatment is constantly expanding. In-well injection and production technology, with its advantages of low treatment costs, low surface wastewater discharge load, and reduced energy consumption per ton of oil production, has become an effective technical means for on-site treatment of produced fluids downhole. In-well injection and production involves using an oil-water separator downhole to separate the oil and water phases. The separated water is directly reinjected into the injection layer, while the low-water-content oil-water mixture is lifted to the surface, enabling simultaneous oil production and water injection operations within the same well.

[0003] Existing technology, such as patent application CN101773742A, discloses a multilayer isofluidic coalescing oil-water separator and its separation method. In this method, the oil-water mixture first flows through each settling cup on the separator's central tube, contacting multiple prismatic surfaces at the bottom of the settling cup. The surface of the settling cup has oleophilic and hydrophobic properties, while the ridge line surface at the included angle between the two outer prismatic surfaces at the bottom of the settling cup has slight oleophilic properties. Oil droplets separated from the oil-water mixture, under the influence of buoyancy and the oleophilic surface material, aggregate along the prismatic surface angle and accelerate upwards. They collide and coalesce at the ridge line, forming larger diameter oil droplets, which then rise and overflow the settling cup along the upper outer wall. The separated water flows into the central tube through the inlet hole and is discharged. However, this sedimentation separation method still has drawbacks. The oil-water separation in the mixture is incomplete, and the water phase carrying oil droplets is directly discharged into the injection layer, causing loss of crude oil resources and affecting the injection performance of the injection layer. Summary of the Invention

[0004] Therefore, it is necessary to provide an oil-water separation device and method using oleophilic packing gravity separation to address the current technical problem of incomplete oil-water separation in oil-water mixtures.

[0005] The above objectives are achieved through the following technical solutions:

[0006] An oil-water separation device using gravity separation with oleophilic packing material includes multiple separation units arranged vertically. Each separation unit includes a central sleeve and a settling cup. The central sleeve extends vertically and includes an inner tube and an outer tube, forming an inner separation cavity between them. The outer tube has a radially penetrating first liquid inlet and an oil outlet, and the inner tube has a radially penetrating second liquid inlet. The settling cup is coaxially disposed outside the outer tube, and its interior forms an outer separation cavity. A spacer is provided between the settling cups of two adjacent separation units. The separation unit has a gap that communicates with the outer separation chamber, which in turn communicates with the inner separation chamber via a first inlet. At least one of the separation units has an inner separation chamber equipped with a spiral separation cylinder, which is coaxially positioned between the outer and inner tubes. The outer wall of the spiral separation cylinder is equipped with spiral blades. The first inlet is used to guide the oil-water mixture, initially separated by the outer separation chamber, onto the spiral blades for secondary centrifugal separation. The oil outlet is used to return the oil after secondary separation to the outer separation chamber, and the second inlet is used to discharge the aqueous phase after secondary separation into the inner tube.

[0007] Furthermore, from top to bottom, each of the second and subsequent separation units is equipped with a spiral separator. The upper end of the spiral separator is fixedly connected to the inner wall of the outer tube. A liquid inlet annular space is formed between the outer wall of the spiral separator and the inner wall of the outer tube, and an oil outlet annular space is formed between the inner wall of the spiral separator and the outer wall of the inner tube. The first liquid inlet is connected to the liquid inlet annular space, and the oil outlet is connected to the oil outlet annular space. The second liquid inlet is connected to the interior of the inner tube.

[0008] Furthermore, the upper end of the spiral separator is provided with a conical connecting part, the large end of the conical connecting part is set upward, and the large end of the conical connecting part is fixedly connected to the inner wall of the outer tube.

[0009] Furthermore, the settling cup has a bottom surface and a cup body. The bottom surface is conical, with the smaller end of the conical shape facing downwards. The bottom surface is formed by splicing together multiple facets distributed circumferentially around the outer tube, with convex and concave facets alternating between adjacent facets. The cup body has an upper edge, which is serrated. The number of teeth in the serration is the same as the number of convex facets, and the tips of each tooth correspond one-to-one with the positions of each convex facet. The oil outlet is located on the upper edge of the cup body.

[0010] Furthermore, the inner wall of the outer tube is also provided with a sand collecting plate, which is located below the spiral separator and is used to collect the sand particles separated by the spiral separator. The sand collecting plate is a conical plate with the large conical end facing downward and fixedly connected to the inner wall of the outer tube.

[0011] Furthermore, the outer tube is provided with a radially penetrating sand discharge hole, which is used to discharge the sand particles collected by the sand collecting plate of the previous separation unit into the outer separation chamber of the next separation unit.

[0012] Furthermore, the sand discharge hole and the first liquid inlet are offset from each other in the circumferential direction of the settling cup.

[0013] Furthermore, each settling cup has multiple sand settling ports on its bottom surface. The sand settling ports are located on the concave edge of the bottom surface and are evenly distributed around the circumference of the settling cup. The sand settling ports are set in one-to-one correspondence with the sand discharge holes, so that the sand particles discharged from the sand discharge holes can enter the corresponding sand settling ports.

[0014] Furthermore, the sand discharge hole and the second liquid inlet are offset from each other in the radial direction of the inner tube.

[0015] Furthermore, the pitch of the spiral blades on each spiral separator gradually decreases from top to bottom.

[0016] Furthermore, a suction pump is connected to the upper end of the inner tube, which is used to pump the aqueous phase after secondary separation to the injection layer.

[0017] Furthermore, the outer separation cavity is provided with an oleophilic packing material, which is used to adsorb and coalesce oil droplets.

[0018] Furthermore, both the first and second liquid inlets are oblong holes, and the length of the oblong holes extends in the vertical direction.

[0019] A gravity separation method for oil-water separation using oleophilic packing material, employing the aforementioned gravity separation device for oil-water separation using oleophilic packing material, includes the following steps:

[0020] S1. The oil-water mixture is allowed to enter the external separation chamber through the gap between the settling cups, so that the oil-water mixture undergoes preliminary sedimentation and separation in the external separation chamber.

[0021] S2. The oil-water mixture in the external separation chamber enters the outside of the spiral separator cylinder through the first liquid inlet, thereby generating centrifugal force under the action of the spiral blades for secondary centrifugal separation.

[0022] S3. The oil after secondary separation returns to the outer separation chamber through the oil outlet, and the aqueous phase after secondary separation is discharged into the inner pipe through the second liquid inlet.

[0023] Furthermore, step S2 also includes: the sand particles generated after the oil-water mixture is separated by the spiral blades fall to the sand collection plate and are collected, and then discharged into the outer separation chamber of the next separation unit through the sand discharge hole, and finally discharged downward from the sand discharge port.

[0024] The beneficial effects of this invention are:

[0025] The oil-water separation device and method provided by the present invention with oleophilic filler gravity separation firstly, large oil droplets in the oil-water mixture gather and float in the outer separation chamber, while small oil droplets enter the inner separation chamber with the oil-water mixture, and are further separated under the centrifugal action of the spiral blades, which can improve the degree of oil-water separation and avoid waste of crude oil resources.

[0026] Secondly, the sand collecting plate can receive sand particles and transfer the sand particles collected in the previous separation unit downward to the settling cup of the next separation unit through the sand discharge hole, and finally discharge them downward through the sand discharge port, so as to avoid the accumulation of sand particles and prevent sand particles from entering the spiral blades and inner tubes to cause wear and blockage.

[0027] Third, because the smaller the pitch, the longer the flow path of the oil-water mixture on the spiral blades, and the greater the centrifugal force, while the oil-water mixture entering the lower separation unit has a high sand content, this setting can gradually improve the centrifugal separation capacity from top to bottom, and promote the separation of sand particles from the oil-water mixture. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of an oil-water separation device using gravity separation with oleophilic packing provided in an embodiment of the present invention;

[0029] Figure 2 This is a side view of an oil-water separation device using gravity separation with oleophilic packing material, according to an embodiment of the present invention.

[0030] Figure 3 for Figure 2 Schematic diagram of the AA section;

[0031] Figure 4 for Figure 3 Enlarged view of the structure at point X;

[0032] Figure 5 This is a schematic diagram of the settling cup in an oil-water separation device using oleophilic packing gravity separation according to an embodiment of the present invention;

[0033] Figure 6 This is a side view of the settling cup in an oil-water separation device using oleophilic packing gravity separation according to an embodiment of the present invention.

[0034] Figure 7 for Figure 6 Schematic diagram of the BB section.

[0035] in:

[0036] 100. Separation unit; 101. Settling cup; 102. Oil outlet; 103. Sand outlet; 104. First liquid inlet; 105. Second liquid inlet; 106. Spiral blade; 107. Sand collecting plate; 108. Sand discharge hole; 109. Central sleeve; 110. Positioning pin; 111. Gap; 112. Inner tube; 113. Outer tube; 114. Spiral separator cylinder; 200. Outer separation chamber; 300. Inner separation chamber. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0038] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this invention, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] like Figures 1 to 7As shown in the figure, an embodiment of the present invention provides an oil-water separation device using gravity separation with oleophilic packing material, comprising a separation unit 100. Multiple separation units 100 are arranged along the vertical direction, each including a central sleeve 109 and a settling cup 101. The axis of the central sleeve 109 extends vertically and includes an inner tube 112 and an outer tube 113, forming an inner separation cavity 300 between the inner tube 112 and the outer tube 113. The outer tube 113 has a radially penetrating first liquid inlet 104 and an oil outlet 102, and the inner tube 112 has a radially penetrating second liquid inlet 105. The settling cup 101 is coaxially disposed outside the outer tube 113, and the interior of the settling cup 101 forms an outer separation cavity 200. The settling of two adjacent separation units 100... A gap 111 is provided between the cups 101, the gap 111 is connected to the outer separation chamber 200, the outer separation chamber 200 is connected to the inner separation chamber 300 through the first liquid inlet 104; at least one of the separation units 100 has a spiral separation cylinder 114 in the inner separation chamber 300, the spiral separation cylinder 114 is coaxially arranged between the outer tube 113 and the inner tube 112, and the outer wall of the spiral separation cylinder 114 is provided with spiral blades 106; the first liquid inlet 104 is used to guide the oil-water mixture after preliminary separation in the outer separation chamber 200 onto the spiral blades 106 for secondary centrifugal separation; the oil outlet 102 is used to return the oil after secondary separation to the outer separation chamber 200, and the second liquid inlet 105 is used to discharge the water phase after secondary separation into the inner tube 112.

[0041] Specifically, a positioning pin 110 is provided on the lower end face of the inner tube 112, and a positioning hole is provided on the upper end face of the inner tube 112. The positioning pin 110 can be inserted into the positioning hole, thereby realizing the connection between two adjacent separation units 100.

[0042] The oleophilic filler gravity separation oil-water separation device of the present invention allows large oil droplets in the oil-water mixture to gather and float in the outer separation chamber 200, while small oil droplets enter the inner separation chamber 300 with the oil-water mixture, and are further separated under the centrifugal action of the spiral blades 106, thereby improving the degree of oil-water separation and avoiding the waste of crude oil resources.

[0043] Furthermore, from top to bottom, each of the second and subsequent separation units 100 is equipped with a spiral separator 114. The upper end of the spiral separator 114 is fixedly connected to the inner wall of the outer tube 113. A liquid inlet annular space is formed between the outer wall of the spiral separator 114 and the inner wall of the outer tube 113, and an oil outlet annular space is formed between the inner wall of the spiral separator 114 and the outer wall of the inner tube 112. The first liquid inlet 104 communicates with the liquid inlet annular space, and the oil outlet 102 communicates with the oil outlet annular space. The second liquid inlet 105 communicates with the interior of the inner tube 112. In this way, the spiral separator 114 separates two annular spaces. The oil-water mixture to be separated enters the liquid inlet annular space, while the separated oil phase enters the oil outlet annular space. The two liquids do not interfere with each other, avoiding secondary mixing.

[0044] Furthermore, the upper end of the spiral separator 114 is provided with a conical connecting part, the larger end of which faces upward and is fixedly connected to the inner wall of the outer tube 113. The conical connecting part can guide the oil-water mixture into the inlet annular space, avoiding the formation of eddies.

[0045] Furthermore, the settling cup 101 has a bottom surface and a cup body. The bottom surface is conical, with the smaller end of the cone facing downwards. The bottom surface is formed by splicing together multiple ribs distributed circumferentially around the outer tube 113, with alternating convex and concave ribs between adjacent ribs. The cup body has an upper edge, which is serrated. The number of serrations is the same as the number of convex ribs, and the tips of each serration correspond one-to-one with the positions of each convex rib. The oil outlet 102 is located on the upper edge of the cup body. This design allows the bottom surface of the settling cup 101 to facilitate the flow of the oil-water mixture along the concave ribs to the first inlet 104, while simultaneously promoting the settling and aggregation of solid sand particles and the collision and aggregation of oil droplets.

[0046] Furthermore, the inner wall of the outer tube 113 is also provided with a sand collecting plate 107. The sand collecting plate 107 is located below the spiral separator 114 and is used to collect the sand particles separated by the spiral separator 114. The sand collecting plate 107 is a conical plate, with the large conical end of the sand collecting plate 107 facing downwards and fixedly connected to the inner wall of the outer tube 113. The sand collecting plate 107 can receive the sand particles, preventing the sand particles from directly entering the inner tube 112 and blocking the second liquid inlet 105.

[0047] Furthermore, the outer tube 113 is provided with a radially penetrating sand discharge hole 108, which is used to discharge the sand collected by the sand collecting plate 107 of the previous separation unit 100 into the outer separation chamber 200 of the next separation unit 100. In this way, the sand collected by the previous separation unit 100 is transferred downward to the settling cup 101 of the next separation unit 100, avoiding the accumulation of sand inside a single separation unit 100.

[0048] Furthermore, the sand discharge hole 108 and the first liquid inlet 104 are offset from each other in the circumferential direction of the settling cup 101. This prevents the sand particles that have just been discharged from being immediately sucked into the inner separation chamber 300 by the first liquid inlet 104, and avoids the sand particles flowing back into the spiral separator 114, causing wear and blockage.

[0049] Furthermore, each settling cup 101 has multiple settling ports 103 on its bottom surface. These ports 103 are located on concave edges of the bottom surface and are evenly distributed around the circumference of the settling cup 101. Each settling port 103 corresponds to a sand discharge hole 108, allowing sand particles discharged from the sand discharge hole 108 to enter the corresponding settling port 103. This allows the sand particles to collect along the concave edges of the bottom surface of the settling cup 101 and be discharged downwards through the settling ports 103. The one-to-one correspondence between the settling ports 103 and the sand discharge holes 108 facilitates the formation of a continuous sand discharge channel.

[0050] Furthermore, the sand discharge hole 108 and the second liquid inlet 105 are offset in the radial direction of the inner tube 112. This prevents sand particles in the sand collecting plate 107 from approaching the second liquid inlet 105 of the inner tube 112 when they are discharged into the sand discharge hole 108, thus preventing sand particles from entering the inner tube 112.

[0051] Furthermore, the pitch of the spiral blades 106 on each spiral separator cylinder 114 gradually decreases from top to bottom. Since the smaller the pitch, the longer the flow path of the oil-water mixture on the spiral blades 106, the greater the centrifugal force, and the higher the sand content in the oil-water mixture entering the lower separation unit 100, this setting can gradually improve the centrifugal separation capacity from top to bottom, and promote the separation of sand particles from the oil-water mixture.

[0052] Furthermore, a suction pump is connected to the upper end of the inner pipe 112. The suction pump is used to draw the aqueous phase after secondary separation to the injection layer. Specifically, the suction pump is installed on the ground. The suction pump provides power to the aqueous phase in the inner pipe 112, guiding the aqueous phase after secondary separation to be continuously transported upwards for reinjection.

[0053] Furthermore, the outer separation cavity 200 is equipped with an oleophilic packing material, which is used to adsorb and coalesce oil droplets. The oleophilic packing material provides a large number of coalescence interfaces, allowing tiny oil droplets to adsorb, collide, and merge into larger oil droplets when the oil-water mixture flows through it, thereby improving the gravity settling efficiency of the oleophilic packing material. The oleophilic packing material is an oleophilic porous medium, such as porous fibers, coalescing mesh, or particulate packing.

[0054] Furthermore, both the first liquid inlet 104 and the second liquid inlet 105 are oblong holes, with the length of the oblong hole extending vertically. This increases the flow area of ​​the first liquid inlet 104 and the second liquid inlet 105, making them less prone to blockage by sand particles.

[0055] Based on the above embodiments, the usage principle and working process of the embodiments of the present invention are as follows:

[0056] The oil-water mixture produced from the oilfield enters the outer separation chamber 200 of each separation unit 100 through the gap 111 between adjacent settling cups 101. Subsequently, the oil-water mixture comes into full contact with the oleophilic packing material in the outer separation chamber 200. Tiny oil droplets in the liquid phase are adsorbed, collided, and aggregated by the oleophilic packing material to form large-diameter oil droplets. The large oil droplets float and accumulate under the action of buoyancy, while the oil-water mixture carrying the fine oil droplets continues to flow and enters the inlet annular space through the first inlet 104. Then, it flows downward along the spiral blades 106 on the outer wall of the spiral separator 114. The oil-water mixture undergoes centrifugal separation within the spiral channel formed by the spiral blades 106, achieving secondary separation.

[0057] During the secondary centrifugal separation process, the denser solid sand particles move outward and downward and fall onto the sand collecting plate 107 to collect. The oil phase separated in the secondary separation flows into the oil discharge annular space, and then flows back to the outer separation chamber 200 through the oil outlet 102 to continue to enrich and float, eventually converging to form an oil phase product that rises to the ground. The aqueous phase, after most of the oil droplets have been removed, enters the inner pipe 112 through the second liquid inlet 105, and is transported upward under the traction of the suction pump at the upper end of the inner pipe 112, and reinjected into the injection layer.

[0058] In this system, sand particles collected by the sand collecting plate 107 are discharged into the outer separation chamber 200 of the next separation unit 100 through the sand discharge hole 108 on the outer pipe 113. The sand particles gather along the concave edge of the bottom surface of the settling cup 101 and are finally discharged outward from the sand discharge port 103 at the concave edge. The pitch of the spiral blades 106 of each separation unit 100 gradually decreases from top to bottom, enabling the lower oil-water mixture to achieve a stronger centrifugal separation effect, thereby removing residual fine oil droplets and solid particles from the oil-water mixture step by step. This oleophilic packing gravity separation oil-water separation device relies on a combination of gravity coalescence settling and spiral centrifugal separation to simultaneously complete oil-water separation and solid phase sand removal, reduce the oil content of the reinjected water, reduce the risk of injection layer blockage, and meet the needs of oilfields for on-site treatment of produced fluids in the same well injection and production well.

[0059] A gravity separation method for oil-water separation using oleophilic packing material, employing the aforementioned gravity separation device for oil-water separation using oleophilic packing material, includes the following steps:

[0060] S1. The oil-water mixture is allowed to enter the outer separation chamber 200 through the gap 111 between the settling cups 101, so that the oil-water mixture undergoes preliminary sedimentation and separation in the outer separation chamber 200.

[0061] S2. The oil-water mixture in the outer separation chamber 200 enters the outside of the spiral separator 114 through the first liquid inlet 104, thereby generating centrifugal force under the action of the spiral blades 106 for secondary centrifugal separation.

[0062] S3. The oil after secondary separation returns to the outer separation chamber 200 through the oil outlet 102, and the aqueous phase after secondary separation is discharged into the inner pipe 112 through the second liquid inlet 105.

[0063] This process first achieves initial oil-water separation through gravity coalescence and sedimentation, and then uses a spiral separator 114 for secondary fine oil-water separation. Large oil droplets are removed in the outer separation chamber 200, while fine oil droplets are separated by the spiral separator 114 in the inner separation chamber 300. Overall, the separation load is reasonably distributed, improving the oil-water separation efficiency.

[0064] Furthermore, step S2 also includes: the sand particles generated after the oil-water mixture is separated by the spiral blade 106 fall to the sand collection plate 107 and are collected, and then discharged into the outer separation chamber 200 of the next separation unit 100 through the sand discharge hole 108, and finally discharged downward from the sand discharge port 103. This enables continuous sand discharge and meets the requirements of injection and production conditions in the same well.

[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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, they should be considered to be within the scope of this specification.

[0066] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An oil-water separation device using gravity separation with oleophilic packing material, characterized in that, include: Separation units, wherein multiple separation units are provided along the vertical direction, and each separation unit includes: A central sleeve, the axis of which extends in the vertical direction, the central sleeve includes an inner tube and an outer tube, an inner separation cavity is formed between the inner tube and the outer tube, the outer tube is provided with a first liquid inlet and an oil outlet that penetrate radially, and the inner tube is provided with a second liquid inlet that penetrates radially. A settling cup is coaxially disposed outside the outer tube, and an outer separation cavity is formed inside the settling cup; a gap is provided between the settling cups of two adjacent separation units, and the gap communicates with the outer separation cavity; the outer separation cavity communicates with the inner separation cavity through a first liquid inlet. At least one of the separation units has a spiral separation cylinder in its inner separation chamber, which is coaxially arranged between the outer tube and the inner tube. The outer wall of the spiral separation cylinder is provided with spiral blades. The first liquid inlet is used to guide the oil-water mixture after preliminary separation in the outer separation chamber onto the spiral blades for secondary centrifugal separation. The oil outlet is used to return the oil after secondary separation to the outer separation chamber. The second liquid inlet is used to discharge the aqueous phase after secondary separation into the inner tube.

2. The oleophilic packing gravity separation oil-water separator according to claim 1, characterized in that, From top to bottom, each of the second and subsequent separation units is equipped with a spiral separator. The upper end of the spiral separator is fixedly connected to the inner wall of the outer tube. A liquid inlet annular space is formed between the outer wall of the spiral separator and the inner wall of the outer tube. An oil outlet annular space is formed between the inner wall of the spiral separator and the outer wall of the inner tube. The first liquid inlet is connected to the liquid inlet annular space, and the oil outlet is connected to the oil outlet annular space. The second liquid inlet is connected to the interior of the inner tube.

3. The oleophilic packing gravity separation oil-water separation device according to claim 2, characterized in that, The upper end of the spiral separator is provided with a conical connecting part, the large end of the conical connecting part is set upward, and the large end of the conical connecting part is fixedly connected to the inner wall of the outer tube.

4. The oleophilic packing gravity separation oil-water separator according to claim 3, characterized in that, The settling cup has a bottom surface and a cup body. The bottom surface is conical with the smaller end of the cone facing downwards. The bottom surface is formed by splicing together multiple facets distributed around the circumference of the outer tube, with convex and concave facets alternating between adjacent facets. The cup body has an upper edge that is serrated. The number of serrations is the same as the number of convex facets, and the tips of each serration correspond one-to-one with the positions of each convex facet. The oil outlet is located on the upper edge of the cup body.

5. The oleophilic packing gravity separation oil-water separator according to claim 4, characterized in that, The inner wall of the outer tube is also provided with a sand collecting plate, which is located below the spiral separator and is used to collect the sand particles separated by the spiral separator. The sand collecting plate is a conical plate with the large conical end facing down and fixedly connected to the inner wall of the outer tube.

6. The oleophilic packing gravity separation oil-water separation device according to claim 5, characterized in that, The outer tube is provided with a radially penetrating sand discharge hole, which is used to discharge the sand particles collected by the sand collection plate of the previous separation unit into the outer separation chamber of the next separation unit.

7. The oleophilic packing gravity separation oil-water separation device according to claim 6, characterized in that, The sand discharge hole and the first liquid inlet are offset from each other in the circumferential direction of the settling cup.

8. The oleophilic packing gravity separation oil-water separator according to claim 7, characterized in that, Each settling cup has multiple sand settling ports on its bottom surface. The sand settling ports are located on the concave edge of the bottom surface and are evenly distributed around the circumference of the settling cup. Each sand settling port is set in correspondence with a sand discharge hole, so that the sand particles discharged from the sand discharge hole can enter the corresponding sand settling port.

9. The oleophilic packing gravity separation oil-water separation device according to claim 8, characterized in that, The sand discharge hole and the second liquid inlet are offset from each other in the radial direction of the inner tube.

10. The oleophilic packing gravity separation oil-water separator according to claim 8, characterized in that, The pitch of the spiral blades on each spiral separator gradually decreases from top to bottom.

11. The oleophilic packing gravity separation oil-water separator according to claim 8, characterized in that, The upper end of the inner tube is connected to a suction pump, which is used to pump the aqueous phase after secondary separation to the injection layer.

12. The oleophilic packing gravity separation oil-water separator according to claim 8, characterized in that, The outer separation chamber is equipped with an oleophilic packing material, which is used to adsorb and coalesce oil droplets.

13. The oleophilic packing gravity separation oil-water separator according to claim 8, characterized in that, Both the first liquid inlet and the second liquid inlet are oblong holes, and the length of the oblong holes extends in the vertical direction.

14. A gravity separation method for oil-water separation using oleophilic packing material, employing the oleophilic packing material gravity separation oil-water separation device according to any one of claims 8 to 13, characterized in that, Includes the following steps: S1. The oil-water mixture is allowed to enter the external separation chamber through the gap between the settling cups, so that the oil-water mixture undergoes preliminary sedimentation and separation in the external separation chamber. S2. The oil-water mixture in the external separation chamber enters the outside of the spiral separator cylinder through the first liquid inlet, thereby generating centrifugal force under the action of the spiral blades for secondary centrifugal separation. S3. The oil after secondary separation returns to the outer separation chamber through the oil outlet, and the aqueous phase after secondary separation is discharged into the inner pipe through the second liquid inlet.

15. The oil-water separation method using gravity separation with oleophilic packing material according to claim 14, characterized in that, Step S2 also includes: the sand particles generated after the oil-water mixture is separated by the spiral blades fall to the sand collection plate and are collected, and then discharged into the outer separation chamber of the next separation unit through the sand discharge hole, and finally discharged downward from the sand discharge port.

Images