An oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence

Abstract

The present invention relates to an oil-containing wastewater treatment device based on the coordination of vortex flow, flotation and coalescence, belongs to the technical field of oil-containing wastewater treatment, and solves the problem that current treatment devices cannot achieve oil and gas separation. The device comprises: a tank body, a drain pipe is provided at the bottom, and an exhaust pipe is provided at the top; a conical inner cylinder: fixed inside the tank body, a plurality of water distribution pipes are provided at the bottom of its internal space, the liquid outlet ends of the water distribution pipes are arranged along the tangent direction of the conical inner cylinder, the water distribution pipes are connected to the water inlet mechanism, and a coalescing plate is provided between the conical inner cylinder and the tank body; an oil and gas separation mechanism: fixed inside the tank body and located above the conical inner cylinder, comprising an oil collecting hood, the oil collecting hood adopts an upwardly convex arc structure, an outlet is provided in the center of the oil collecting hood, a baffle is provided above the outlet, the top of the collection area above the oil collecting hood is connected to the exhaust pipe provided on the top of the tank body, and the bottom is connected to the oil drain pipe provided on the side of the tank body. The sewage treatment device of the present invention meets the requirements of oil and gas separation.

Description

Technical Field

[0001] The present invention belongs to the technical field of oily wastewater treatment, and in particular relates to an oily wastewater treatment device based on the coordination of cyclone, flotation and coalescence. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Currently, the construction cost of offshore oil and gas production platforms is high. How to simplify the sewage treatment process, shorten the sewage treatment time, and reduce the equipment footprint has become an urgent problem to be solved in the development of deepwater oil fields.

[0004] Currently, it is increasingly difficult for a single water treatment technology to meet water quality requirements. The simple series connection of different water treatment processes not only creates system redundancy and complex operations, but also increases floor space, limits application scenarios, and reduces economic benefits. To overcome these shortcomings, cyclone flotation technology is currently used to treat oily wastewater. This technology couples cyclone separation technology with flotation technology. Bubbles and oil droplets move "centripetally" in a centrifugal field. This directional movement concentrates the concentration of oil droplets and bubbles, while effectively overcoming the constraints of water phase streamlines on oil droplets and improving the efficiency of oil droplet-bubble collisions. Test results of most current cyclone flotation devices in oilfields have shown that cyclone flotation technology has superior oil-water separation performance compared to single water treatment technologies.

[0005] Both U.S. patent application US9938164B2 and Chinese patent application CN110482635A disclose a liquid-sealed cyclone flotation device, comprising a tank body, an interior of which is provided with a conical inner cylinder, through which sewage is introduced tangentially along the inner edge of the conical inner cylinder. This device applies cyclone flotation technology to the oil-water separation of oily sewage, overcoming the defects of current oily sewage treatment equipment. However, neither of the above-mentioned patent applications considers the problem of oil-gas separation in their structures, resulting in the gas being discharged together with the treated oil. Furthermore, neither of the above-mentioned cyclone flotation devices considers the problem of maintaining the cyclone field when the flow rate changes. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an oily wastewater treatment device based on the coordination of cyclone, flotation and coalescence, which can achieve oil and gas separation and overcome the defects of current oily wastewater treatment devices.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] An embodiment of the present invention provides an oily wastewater treatment device based on the coordination of cyclone, flotation and coalescence, comprising:

[0009] Tank body: There is a drain pipe at the bottom and an exhaust pipe at the top;

[0010] Conical inner cylinder: fixed inside the tank body, with multiple water distribution pipes at the bottom of its internal space. The liquid outlet ends of the water distribution pipes are arranged along the tangent direction of the conical inner cylinder. The water distribution pipes are connected to the water inlet mechanism. A coalescing plate is provided between the conical inner cylinder and the tank body.

[0011] Oil-gas separation mechanism: fixed inside the tank body and located above the conical inner cylinder, including an oil collecting hood. The oil collecting hood adopts an upward-convex arc structure. An opening is provided in the center of the oil collecting hood, and a baffle is provided above the opening. The top of the collection area above the oil collecting hood is connected to the exhaust pipe located on the top of the tank body, and the bottom of the collection area is connected to the oil drain pipe located on the side of the tank body.

[0012] Optionally, a coalescing plate is provided between the upper portion of the conical inner cylinder and the tank body to filter the water discharged from the conical inner cylinder again.

[0013] Optionally, the agglomeration plate is made of random agglomeration packing or structured agglomeration packing.

[0014] Optionally, the agglomeration plate has a thickness of not less than 30 mm.

[0015] Optionally, an inverted conical collecting bin is provided at the bottom of the conical inner cylinder, the bottom of the inverted conical collecting bin is connected to one end of a sewage pipe, and the other end of the sewage pipe extends to the outside of the tank body.

[0016] Optionally, the water inlet mechanism includes a first water inlet pipe and a second water inlet pipe, the part of the first water inlet pipe extending into the conical inner cylinder passes through the vertical sleeve located at the bottom of the conical inner cylinder in a vertical posture, the second water inlet pipe is connected to the vertical sleeve, the vertical sleeve is connected to multiple first water distribution pipes, the water outlet end of the first water inlet pipe is connected to multiple second water distribution pipes, the first water distribution pipe and the second water distribution pipe have different heights along the axial direction of the conical inner cylinder, and are staggered at equal intervals along the circumference of the conical inner cylinder.

[0017] Optionally, both the first water inlet pipe and the second water inlet pipe are provided with control valves.

[0018] Optionally, the ratio of the maximum diameter of the conical inner cylinder to the diameter of the tank body is 1 / 2-3 / 4, and the angle between the conical wall of the conical inner cylinder and the vertical direction is 8°-14°.

[0019] Optionally, a rectifying plate is provided on the top of the conical inner cylinder, and the rectifying plate is provided with a plurality of channels extending in a direction parallel to the axis of the conical inner cylinder to convert the spiral motion of the fluid into motion along the axial direction of the conical inner cylinder.

[0020] Optionally, a liquid level detection element is provided on the top of the tank body.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The oily wastewater treatment device of the present invention is provided with an oil collecting hood and a baffle, and an opening is provided in the center of the oil collecting hood. After the oily wastewater passes through the conical inner cylinder for flotation separation, light components such as air bubbles and oil droplet adherents rise to the bottom surface of the oil collecting hood and flow to the collection area above the oil collecting hood through the opening. The oil phase of the adherents falls to the oil collecting hood under the action of the baffle and flows along the oil collecting hood, and is finally discharged through the oil drain pipe. The gas phase of the adherents rises and is discharged through the exhaust pipe, thereby realizing oil and gas separation and avoiding the common discharge of gas and treated oil products. In addition, the oil collecting hood and the baffle are arranged inside the tank body, and there is no need to add additional oil and gas separation equipment outside the tank body, so that the entire oily wastewater treatment device has a compact structure, a small size, and strong adaptability to installation sites.

[0023] 2. The oily wastewater treatment device of the present invention is provided with a coalescing plate, which can filter the water discharged from the conical inner cylinder again to ensure the oil-water separation effect. At the same time, a drain pipe is provided at the bottom of the tank body and a sewage pipe is provided at the bottom of the conical inner cylinder. After the cleaning water is introduced into the drain pipe, the coalescing plate can be cleaned. The cleaned water enters the inner conical cylinder and flows out from the sewage pipe, which facilitates the cleaning and maintenance of the coalescing plate and ensures the treatment effect of the sewage treatment device.

[0024] 3. In the oily wastewater treatment device of the present invention, the vertical sleeve is connected to multiple first water distribution pipes, the water outlet end of the first water inlet pipe is connected to multiple second water distribution pipes, the first water distribution pipes and the second water distribution pipes have different axial heights along the conical inner cylinder, and are staggered at equal intervals along the circumference of the conical inner cylinder, and control valves are provided on the first water inlet pipe and the second water inlet pipe. The opening of the control valve and the number of activated water inlet pipes can be adjusted according to the incoming liquid flow rate to ensure the flow rate of the water distribution pipe to maintain the vortex field in the conical inner cylinder, which solves the problem of maintaining the vortex field at low flow rate. Compared with the traditional design in which all water distribution pipes are connected to the same water inlet pipe, the adaptability to flow changes is stronger. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 This is a schematic diagram of the overall structure of Example 1 of the present invention;

[0027] Figure 2 This is a cross-sectional view of the overall structure of Example 1 of the present invention;

[0028] Figure 3 This is a schematic diagram of the internal structure of the tank body according to embodiment 1 of the present invention;

[0029] Figure 4 This is a schematic diagram of the water inlet mechanism of Example 1 of the present invention;

[0030] Among them, 1. rectifier plate, 2. oil collecting hood, 3. opening, 4. baffle, 5. exhaust pipe, 6. oil drain pipe, 7. drain pipe, 8. tank wall, 9. upper head, 10. lower head, 11. bottom inverted cone section, 12. middle cylindrical section, 13. upper right cone section, 14. top cylindrical section, 15. drain pipe, 16. first water inlet pipe, 17. second water inlet pipe, 18. water inlet pipe, 19. vertical sleeve, 20. first water distribution pipe, 21. second water distribution pipe, 22. control valve, 23. coalescing plate, 24. manhole, 25. support leg, 26. liquid level detection element. DETAILED DESCRIPTION

[0031] Example 1

[0032] This embodiment provides an oily wastewater treatment device based on the coordination of cyclone, flotation and coalescence, such as Figure 1-Figure 3 As shown, it includes a tank body, a conical inner cylinder is coaxially arranged inside the tank body, a plurality of water distribution pipes are provided at the bottom of the internal space of the conical inner cylinder, and the liquid outlet ends of the plurality of water distribution pipes are arranged along the tangent direction of the conical inner cylinder, which are used to pass the sewage to be treated into the conical inner cylinder, and the water distribution pipes are connected to the water inlet mechanism, which is used to pass the sewage to be treated into the water distribution pipes. A rectifier plate 1 is provided at the top of the conical inner cylinder for converting the rotational motion of the fluid in the conical inner cylinder into a stable axial flow, and an oil-gas separation mechanism fixed to the tank body is provided above the conical inner cylinder. , used to separate gas and oil, the oil and gas separation mechanism includes an oil collecting hood 2, the oil collecting hood 2 is fixedly connected to the tank body, the space above the oil collecting hood 2 is the collection area, the center position of the oil collecting hood is provided with an opening 3, a baffle 4 is provided above the opening 3, an exhaust pipe 5 is provided at the top center position of the tank body, for discharging the gas separated by the oil and gas separation mechanism, an oil drain pipe 6 is also provided on the upper part of the tank body, for discharging the oil separated by the oil and gas separation mechanism, and a drain pipe 7 is also provided at the bottom center position of the tank body, for discharging the treated water.

[0033] The tank body adopts a cylindrical structure, including a cylindrical tank wall 8, an upper head 9 is fixed to the top of the tank wall 8, and a lower head 10 is fixed to the bottom of the tank wall 8. The tank wall 8, the upper head 9 and the lower head 10 form a sealed cavity structure. The exhaust pipe 5 is coaxially arranged at the center position of the upper head 9, and the drain pipe 7 is coaxially arranged at the center position of the lower head 10.

[0034] Furthermore, the exhaust pipe 5 and the drain pipe 7 are both provided with valves to control their opening and closing.

[0035] A conical inner cylinder is coaxially arranged inside the tank body. From bottom to top, the conical inner cylinder includes a bottom inverted cone section 11, a middle cylindrical section 12, an upper positive cone section 13 and a top cylindrical section 14 in sequence. The maximum diameter ratio of the four sections is: 1:1:1:0.5. The bottom end area of the bottom inverted cone section 11 is smaller than the top end area, and the bottom end area of the upper positive cone section 13 is larger than the top end area. From bottom to top, the space inside the entire conical inner cylinder is a solid collection area, a vortex generating area and a rectification area in sequence. Among them, the bottom inverted cone section 11 serves as an inverted cone collecting bin, which is used as a solid collection area. The middle cylindrical section 12 and the upper positive cone section 13 serve as vortex generating areas, which are the main areas where oil droplets and bubbles collide and adhere. A rectification plate 1 is provided in the top cylindrical section 14 as a rectification area.

[0036] In this embodiment, the smaller the cross-sectional area of the vortex generating zone, the higher the speed of the fluid when passing through the vortex generating zone, and the better the separation effect of the oily wastewater under the action of centripetal force and centrifugal force. However, a larger inclination angle may cause excessive turbulence intensity, resulting in excessive liquid scouring, and then backmixing of oil droplets and bubbles. Therefore, the ratio of the maximum diameter of the conical inner cylinder to the tank diameter is controlled to be 1 / 2-3 / 4, and the angle between the conical wall of the upper positive cone section 13 of the conical inner cylinder and the vertical direction is controlled to be 8°-14°.

[0037] The upper positive cone section 13 is used as the main separation area, and the continuously shrinking cross-sectional area can increase the cyclonic field intensity and accelerate the separation of oil droplets in the oily wastewater.

[0038] The bottom center of the inverted cone-shaped collection bin is connected to one end of a drain pipe 15, and the other end of the drain pipe 15 extends to the outside of the tank body. The drain pipe 15 is used to discharge solid impurities such as mud and sand that are initially separated in the solid collection area to reduce the impact on subsequent treatment effects.

[0039] Furthermore, the sewage pipe 15 is installed with a valve. Under normal working conditions, the valve on the sewage pipe 15 is closed, and the valve on the sewage pipe 15 is opened periodically to discharge sewage.

[0040] The top cylindrical section 14 of the conical inner cylinder is equipped with a rectifier plate 1, the outer circumferential surface of the rectifier plate 1 is fixed to the inner circumferential surface of the top cylindrical section 14, and the rectifier plate 1 includes a plate body, and the plate body is provided with a plurality of channels extending in a direction parallel to the axis of the conical inner cylinder. In this embodiment, the rectifier plate 1 includes a frame, and the frame has a plurality of parallel partitions, and the partitions are parallel to the axis of the conical inner cylinder. A plurality of channels parallel to the axis of the conical inner cylinder are formed between the partitions, and the channels are used for fluid to pass through. In other embodiments, the rectifier plate 1 can be arranged in the form of a porous plate, a concentric plate or a serpentine plate, and those skilled in the art can arrange it according to actual needs.

[0041] The rectifier plate 1 can hinder the rotational flow of the fluid at the top of the conical inner cylinder, converting the rotational motion of the fluid in the conical inner cylinder into a stable axial flow, thereby improving the flow stability of the fluid in the conical inner cylinder and the external space, avoiding the generation of secondary vortexes in the external space of the conical inner cylinder, ensuring the stability of the separation process, and also avoiding the secondary emulsification of the oil droplet and bubble adherents.

[0042] The middle cylindrical section 12 is provided with a plurality of water distribution pipes for introducing sewage into the conical inner cylinder along the tangential direction of the conical inner cylinder.

[0043] The water distribution pipe is connected to the water inlet mechanism, such as Figure 4 As shown, the water inlet mechanism includes a first water inlet pipe 16 and a second water inlet pipe 17. The water inlet ends of the first water inlet pipe 16 and the second water inlet pipe 17 merge into a water inlet inlet pipe 18. The first water inlet pipe 16 and the second water inlet pipe 17 are distributed parallel to the radial direction of the tank body and the conical inner cylinder. The first water inlet pipe 16 is located below the second water inlet pipe 17. The first water inlet pipe 16 and the second water inlet pipe 17 pass through the tank body and extend into the interior of the conical inner cylinder. The first water inlet pipe 16 and the second water inlet pipe 17 are fixedly connected to the tank wall 8 of the tank body. The second water inlet pipe 17 is connected to the The vertical sleeve 19 is connected, and the vertical sleeve 19 is arranged at the bottom of the space inside the conical inner cylinder and is coaxial with the conical inner cylinder. The end of the first water inlet pipe 16 extending into the conical inner cylinder is bent upward, and the bent section coaxially passes through the vertical sleeve 19. The vertical sleeve 19 is coaxially sleeved and fixed on the outer periphery of the upward bent section of the first water inlet pipe 16. The inner diameter of the vertical sleeve 19 is larger than the outer diameter of the upward bent section of the first water inlet pipe 16 so that there is space for sewage flow between the vertical sleeve 19 and the upward bent section of the first water inlet pipe 16.

[0044] The vertical sleeve 19 is connected to multiple first water distribution pipes 20, and the water outlet end of the upward bent section of the first water inlet pipe 16 is connected to multiple second water distribution pipes 21. The first water distribution pipes 20 and the second water distribution pipes 21 have different heights along the axial direction of the conical inner tube, and are staggered at equal intervals along the circumferential direction of the conical inner tube. The first water distribution pipes 20 and the second water distribution pipes 21 are both located in the middle cylindrical section 12 of the conical inner tube.

[0045] Specifically, the vertical sleeve 19 is connected to the liquid inlet ends of two first water distribution pipes 20 arranged at an interval of 180°. The first water distribution pipes 20 are arranged along the radial direction of the conical inner tube, and the liquid outlet ends of the first water distribution pipes 20 are bent 90° so that the sewage flows out along the tangential direction of the conical inner tube.

[0046] The water outlet end of the upwardly bent section of the first water inlet pipe 16 is connected to the liquid inlet ends of two second water distribution pipes 21 arranged at an interval of 180°. The second water distribution pipes 21 are arranged along the radial direction of the conical inner cylinder. The liquid outlet end of the second water distribution pipe 21 is provided with a 90° bend so that the sewage flows out along the tangential direction of the conical inner cylinder.

[0047] In some other embodiments, the vertical sleeve 19 can be connected to three or four or more first water distribution pipes 20, and the water outlet end of the upward bent section of the first water inlet pipe 16 can be connected to three or four or more second water distribution pipes 21. Those skilled in the art can set it according to actual needs.

[0048] Along the axial direction of the conical inner tube, the height of the second water distribution pipe 21 is higher than that of the first water distribution pipe 20. The second water distribution pipe 21 is connected to the pipe section that extends from the upward bending section of the first water inlet pipe 16 to the top of the vertical sleeve 19. With this arrangement, there is no need to process a through hole on the vertical sleeve 19 for the second water distribution pipe 21 to pass through, which makes it more convenient to arrange the second water distribution pipe 21. Along the circumferential direction of the conical inner tube, the first water distribution pipe 20 and the second water distribution pipe 21 are arranged at equal intervals and staggered, that is, adjacent first water distribution pipes 20 and second water distribution pipes 21 are arranged at 90° intervals, which ensures the uniformity of water distribution.

[0049] The water inlet method adopted in this embodiment avoids complex pipeline arrangement, making the device more compact and simple. Multiple water distribution pipes are evenly distributed inside the conical inner cylinder and the water outlet ends of the water distribution pipes are tangent to the wall of the conical inner cylinder, which can produce a uniform and stable flow field, thereby achieving uniform water and air distribution inside the oily wastewater treatment device. The first water inlet pipe 16 uses two second water distribution pipes 21 to deliver sewage, and the second water inlet pipe 17 delivers sewage through the vertical sleeve 19 and the two first water distribution pipes 20.

[0050] The pipe sections of the first water inlet pipe 16 and the second water inlet pipe 17 located outside the tank body are both provided with a control valve 22, which can adjust the flow of the first water inlet pipe 16 and the second water inlet pipe 17 by adjusting the opening of the control valve 22, so that the entire sewage treatment device has a wider flow adjustment range. When the sewage flow is low, the opening of the control valve 22 can be adjusted or one water inlet pipe can be closed to ensure that there is a sufficiently large vortex intensity at the water distribution pipe outlet at a smaller flow rate, promote the collision flotation process of bubbles and oil droplets, and improve the separation efficiency of the device. Compared with the traditional design in which all water distribution pipes are connected to the same water inlet pipe, the adaptability to flow changes is stronger.

[0051] A coalescing plate 23 is provided between the upper positive cone section 13 of the conical inner cylinder and the inner side surface of the tank wall 8. The coalescing plate 23 fixes the conical inner cylinder in the tank body. The treated water flowing out of the conical inner cylinder flows through the coalescing plate 23 under the action of gravity and is filtered again, further reducing the oil concentration in the water and achieving better treatment effect. Finally, the treated water is discharged from the tank body through the drain pipe 7.

[0052] Furthermore, the coalescing plate 23 is arranged between the upper portion of the upper forward cone section 13 and the tank body, which reduces the floating distance of the oil droplets separated by the coalescing plate 23 and improves the separation efficiency to a certain extent.

[0053] In this embodiment, the agglomeration plate 23 is made of random agglomeration packing, having a thickness of not less than 30 mm, which meets the filtration requirements. The random agglomeration packing can be made of existing materials and will not be described in detail here. In other embodiments, the agglomeration plate 23 can be made of structured agglomeration packing, and those skilled in the art can configure it according to actual needs.

[0054] Furthermore, in order to facilitate the installation of the coalescing plate 23, the coalescing plate 23 is composed of a plurality of sector-shaped plates spliced together. Preferably, the coalescing plate 23 is composed of six sector-shaped plates spliced together.

[0055] Furthermore, a manhole 24 is provided on the tank wall 8 at a position corresponding to the coalescing plate 23 to facilitate staff to observe the internal conditions of the tank.

[0056] An oil-gas separation mechanism is provided above the conical inner cylinder. The oil-gas separation mechanism includes an oil collecting cover 2. The oil collecting cover 2 adopts an upwardly convex arc structure. The curvature thereof can be determined according to actual conditions and will not be described in detail here.

[0057] In other embodiments, the oil collecting hood 2 may also adopt a frustum structure with the cone tip facing upward, and those skilled in the art may configure it according to actual needs.

[0058] The oil collecting hood 2 is coaxially fixedly connected to the tank body, and the upper space thereof is a collecting area for collecting oil phase scum and agglomerating gas.

[0059] An opening 3 is coaxially provided at the center of the oil collecting cover 2 , and the opening 3 connects the space above and below the oil collecting cover 2 .

[0060] A baffle 4 is coaxially arranged above the opening 3. Preferably, the baffle 4 is a circular baffle. In other embodiments, the baffle 4 can also be a square plate or a plate of other shapes, and its area needs to meet the requirement of blocking the oil phase.

[0061] The circular baffle is fixedly connected to the top ends of the plurality of support legs 25 , and the bottom ends of the support legs 25 are fixed to the upper surface of the oil collecting hood 2 .

[0062] The plurality of supporting legs 25 are distributed at equal intervals along the circumferential direction of the circular baffle. Preferably, four supporting legs 25 are provided.

[0063] In other embodiments, the circular baffle may also be directly fixed to the tank body via a connecting rod or other connecting parts, and those skilled in the art may configure the baffle according to actual needs.

[0064] The top of the collection area is connected to the exhaust pipe 5 located at the center of the upper head 9, and the exhaust pipe 5 is coaxially arranged with the tank body. The bottom of the collection area is connected to the oil drain pipe 6 arranged on one side of the tank wall 8. The oil drain pipe 6 is arranged along the radial direction of the tank body, and the lower part of the oil drain pipe 6 is flush with the bottom edge of the oil collecting cover 2.

[0065] After the oily wastewater passes through the conical inner cylinder for cyclone flotation separation, light components such as air bubbles and oil droplets adherents rise to the bottom surface of the oil collecting hood 2. As the accumulated light components such as adherents continue to increase, the adherents finally flow through the opening 3 to the collection area above the oil collecting hood 2. The oil phase of the adherents falls to the oil collecting hood 2 under the action of the baffle 4 and flows along the oil collecting hood 2, and is finally discharged through the oil drain pipe 6. The gas phase of the adherents rises and is discharged through the exhaust pipe 5, realizing oil and gas separation and avoiding the discharge of gas and treated oil together.

[0066] Furthermore, the upper head 9 is also equipped with a liquid level detection element 26 to detect the water level height in the tank body. Preferably, the liquid level detection element 26 adopts a radar level meter or an ultrasonic level meter. The electromagnetic waves emitted by the radar level meter or the sound waves emitted by the ultrasonic level meter have certain penetrating properties and can pass through the oil collecting cover 2, thereby realizing the detection of the water level height in the tank body, and adjusting the opening of the control valve 22 by detecting the liquid level height in the tank body.

[0067] In this embodiment, the radar level gauge or ultrasonic level gauge is installed at a position offset from the conical inner cylinder on the upper end cap 9 so that it can detect the level of the purified water outside the conical inner cylinder. Simultaneously, the radar level gauge or ultrasonic level gauge can also monitor the oil level above the oil collecting hood 2.

[0068] By setting the liquid level detection element 26 and the control valve 22, the liquid level in the tank is controlled.

[0069] In the oily wastewater treatment device of this embodiment, the conical inner cylinder and the tank body are connected by a coalescing plate 23, the oil-gas separation mechanism is arranged directly above the conical inner cylinder and is fixed to the tank body, the oil-gas separation mechanism is arranged inside the tank body and does not occupy the external space of the tank body, the various structures are tightly connected, the device has a compact and simple appearance, occupies a small area, has strong adaptability to the installation site, and can achieve low-cost and efficient treatment of oily wastewater.

[0070] The working method of the oily wastewater treatment device of this embodiment is:

[0071] The oily wastewater containing microbubbles first flows into the first water inlet pipe 16 and the second water inlet pipe 17 through the water inlet inlet pipe 18. The flow of the first water inlet pipe 16 and the second water inlet pipe 17 is controlled by the control valve 22. The wastewater flows into the conical inner cylinder and flows out tangentially along the inner wall of the conical inner cylinder under the action of the first water distribution pipe 20 and the second water distribution pipe 21 to form a cyclone field. The centrifugal acceleration at the outlet of the first water distribution pipe 20 and the second water distribution pipe 21 is controlled to be 15-20 gravitational accelerations. Under the constraint of the wall of the conical inner cylinder, the oily wastewater rotates and rises in the cyclone field. In this process, the microbubbles in the oily wastewater are released and collide and adhere with the dispersed phase oil droplets to form an adhered body. Moreover, under the action of the continuously shrinking cross-sectional area in the conical inner cylinder, the cyclone field is continuously enhanced, which further promotes the separation of oil droplets in the wastewater. As light components such as bubbles and oil droplets gradually rise to the top of the conical inner cylinder, the multiple channels of the plate transform the fluid's spiral motion into stable axial flow, providing flow conditions for stable separation in the external space. These rectified light components, such as bubbles and oil droplets, rise to the bottom of the oil hood 2. As the number of these components accumulates, they eventually flow into the collection area through opening 3 in the hood 2. The oil phase in the components, driven by baffle 4, falls to the top of the hood 2 and slides down along its surface, eventually being discharged through drain pipe 6, which is fixed to the tank and flush with the bottom of the hood 2. The gas phase in the components is discharged through exhaust pipe 5 at the center of the upper head 9. High-density impurities such as solid particles within the conical inner cylinder slide down the inner wall and accumulate in the inverted cone collection bin, where they are periodically discharged through drain pipe 15. The treated purified water flows out from the top of the conical inner cylinder and enters the external space of the conical inner cylinder. It is filtered again when flowing through the coalescing plate 23, further reducing the oil concentration in the purified water, and is finally discharged from the drain pipe 7 in the center of the lower head 10.

[0072] When the coalescing plate 23 needs to be cleaned and maintained, it is only necessary to introduce cleaning water into the tank body from the drain pipe 7. When the cleaning water passes through the coalescing plate 23, the coalescing plate 23 is reversely cleaned, and the cleaned water enters the conical inner cylinder through the top of the conical inner cylinder, and is then discharged through the sewage pipe 15. The sewage treatment device of this embodiment can achieve the cleaning and maintenance of the coalescing plate 23 without disassembling the coalescing plate 23. The cleaning and maintenance of the coalescing plate 23 is convenient, thereby ensuring the treatment effect of the sewage treatment device.

[0073] The oily wastewater treatment device of this embodiment can be used to treat oily wastewater in oil fields and petrochemical industries, as well as in daily life and other industrial production processes. It will not be described in detail here.

[0074] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence, characterized in that: include: The tank body is provided with a drain pipe at the bottom and an exhaust pipe at the top; Conical inner cylinder: fixed inside the tank body, with multiple water distribution pipes at the bottom of its internal space. The liquid outlet ends of the water distribution pipes are arranged along the tangent direction of the conical inner cylinder. The water distribution pipes are connected to the water inlet mechanism. A coalescing plate is provided between the conical inner cylinder and the tank body; a rectifying plate is provided on the top of the conical inner cylinder, and the rectifying plate has multiple channels extending in a direction parallel to the axis of the conical inner cylinder; Oil-gas separation mechanism: fixed inside the tank body and located above the conical inner cylinder, including an oil collecting hood. The oil collecting hood adopts an upward convex arc structure, with an opening in the center of the oil collecting hood and a baffle above the opening. The top of the collection area above the oil collecting hood is connected to the exhaust pipe located on the top of the tank body, and the bottom of the collection area is connected to the oil drain pipe located on the side of the tank body; The water inlet mechanism includes a first water inlet pipe and a second water inlet pipe. The portion of the first water inlet pipe extending into the conical inner cylinder passes through a vertical sleeve located at the bottom of the conical inner cylinder in a vertical posture. The second water inlet pipe is communicated with the vertical sleeve. The vertical sleeve is connected to multiple first water distribution pipes. The water outlet end of the first water inlet pipe is connected to multiple second water distribution pipes. The first water distribution pipe and the second water distribution pipe have different heights along the axial direction of the conical inner cylinder and are staggered at equal intervals along the circumference of the conical inner cylinder. The liquid outlet ends of the first water distribution pipe and the second water distribution pipe are provided with a 90° bend so that sewage flows out along the tangential direction of the conical inner cylinder. Adjacent first water distribution pipes and second water distribution pipes are arranged at 90° intervals. The first water inlet pipe and the second water inlet pipe are both provided with a control valve, which can adjust the opening of the control valve and the number of activated water inlet pipes according to the incoming liquid flow rate to ensure the flow rate of the water distribution pipe to maintain the vortex field in the conical inner cylinder.

2. The oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence according to claim 1, characterized in that: The coalescing plate is arranged between the upper portion of the conical inner cylinder and the tank body.

3. The oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence according to claim 1, characterized in that: The agglomeration plate is made of random agglomeration filler or structured agglomeration filler.

4. The oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence according to claim 1, characterized in that: The thickness of the agglomeration plate is not less than 30 mm.

5. The oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence as claimed in claim 1, characterized in that: An inverted conical collecting bin is provided at the bottom of the conical inner cylinder. The bottom of the inverted conical collecting bin is connected to one end of a sewage pipe, and the other end of the sewage pipe extends to the outside of the tank body.

6. The oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence as claimed in claim 1, characterized in that: The ratio of the maximum diameter of the conical inner cylinder to the diameter of the tank body is 1 / 2-3 / 4, and the angle between the conical wall of the conical inner cylinder and the vertical direction is 8°-14°.

7. The oily wastewater treatment device based on the synergy of cyclone, flotation and coalescence as claimed in claim 1, characterized in that: A liquid level detection element is provided on the top of the tank body.

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