Oily sewage treatment device based on cooperation of rotational flow, air floatation and coalescence

Abstract

The invention relates to an oily sewage treatment device based on cooperation of rotational flow, air floatation and coalescence, belongs to the technical field of oily sewage treatment, and solves the problem that a current treatment device cannot realize oil-gas separation, the oily sewage treatment device comprises: a tank body, the bottom of which is provided with a drain pipe and the top of which is provided with an exhaust pipe; the conical inner cylinder is fixed in the tank body, a plurality of water distribution pipes are arranged at the bottom of the inner space of the conical inner cylinder, the liquid outlet ends of the water distribution pipes are arranged in the tangential direction of the conical inner cylinder, the water distribution pipes are connected with the water inlet mechanism, and a coalescence plate is arranged between the conical inner cylinder and the tank body; the oil-gas separation mechanism is fixed in the tank body and located above the conical inner barrel and comprises an oil collecting cover, the oil collecting cover is of an arc-shaped structure protruding upwards, an outlet is formed in the center of the oil collecting cover, a baffle is arranged above the outlet, the top of a collecting area above the oil collecting cover is communicated with an exhaust pipe arranged at the top of the tank body, and the bottom of the collecting area above the oil collecting cover is communicated with an oil discharging pipe arranged on the side portion of the tank body; the sewage treatment device provided by the invention meets the requirement of oil-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] At present, 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] At present, it is increasingly difficult for a single water treatment technology to meet water quality requirements, and the simple series connection of different water treatment processes not only causes system redundancy and complicated operations, but also increases the floor space, limits application scenarios, and reduces economic benefits. In order to overcome the above-mentioned defects, cyclone flotation technology is currently used to treat oily wastewater. This technology is a coupling of cyclone separation technology and 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 collision efficiency of oil droplets and bubbles. At present, the test results of most cyclone flotation devices at oil field sites show that cyclone flotation technology has superior oil-water separation performance compared to single water treatment technology.

[0005] Both the U.S. patent application US9938164B2 and the Chinese patent application CN110482635A disclose a liquid-sealed cyclone flotation device, including a tank body, a conical inner cylinder is provided inside the tank body, and sewage is tangentially introduced into the inner edge of the conical inner cylinder, so as to realize the application of cyclone flotation technology to the oil-water separation of oily sewage, and overcome the defects of the current oily sewage treatment equipment. However, the above two patent applications do not consider the oil-gas separation problem in the structure, resulting in the gas being discharged together with the treated oil, and the above cyclone flotation devices do not consider the problem of maintaining the cyclone field when the flow rate changes. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an oily wastewater treatment device based on the coordination of cyclone, flotation and agglomeration, 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: The embodiment of the present invention provides an oily wastewater treatment device based on the coordination of cyclone, flotation and coalescence, comprising: Tank body: There is 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, and a coalescing plate is provided between the conical inner cylinder and the tank body; 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 upwardly 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 provided on the top of the tank body, and the bottom of the collection area is connected to the oil drain pipe provided on the side of the tank body.

[0008] Optionally, a coalescing plate is disposed between the upper portion of the conical inner cylinder and the tank body to filter the water discharged from the conical inner cylinder again.

[0009] Optionally, the agglomeration plate is made of random agglomeration filler or structured agglomeration filler.

[0010] Optionally, the agglomeration plate has a thickness of not less than 30 mm.

[0011] Optionally, an inverted cone-shaped collecting bin is provided at the bottom of the conical inner cylinder, the bottom of the inverted cone-shaped collecting bin is connected to one end of a sewage discharge pipe, and the other end of the sewage discharge pipe extends to the outside of the tank body.

[0012] 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 a 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 a plurality of first water distribution pipes, the water outlet end of the first water inlet pipe is connected to a plurality of 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 circumferential direction of the conical inner cylinder.

[0013] Optionally, both the first water inlet pipe and the second water inlet pipe are provided with control valves.

[0014] 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°.

[0015] 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 so as to convert the spiral motion of the fluid into motion along the axial direction of the conical inner cylinder.

[0016] Optionally, a liquid level detection element is provided on the top of the tank body.

[0017] The beneficial effects of the present invention are as follows: 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 droplets adherent bodies 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 adherent bodies 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 adherent bodies rises and is discharged through the exhaust pipe, thereby achieving 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 volume, and a strong adaptability to the installation site.

[0018] 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 passed into the drain pipe, the coalescing plate can be cleaned, and 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.

[0019] 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 circumferential direction of the conical inner cylinder, and control valves are provided on the first water inlet pipes and the second water inlet pipes. 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 pipes to maintain the vortex field in the conical inner cylinder, which solves the problem of maintaining the vortex field at low flow rates. 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

[0020] The accompanying drawings in the specification, 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.

[0021] Figure 1 It is a schematic diagram of the overall structure of Embodiment 1 of the present invention; Figure 2 is a cross-sectional view of the overall structure of embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the internal structure of the tank body in Example 1 of the present invention; Figure 4 This is a schematic diagram of the water inlet mechanism of Embodiment 1 of the present invention; 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 positive 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 foot, 26. liquid level detection element. DETAILED DESCRIPTION

[0022] Example 1 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 arranged at the bottom of the inner 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, the water distribution pipes are connected to the water inlet mechanism, and the water inlet mechanism is used to pass the sewage to be treated into the water distribution pipes, and a rectifying plate 1 is provided at the top of the conical inner cylinder, which is used to convert 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 a collection area, an opening 3 is provided at the center of the oil collecting hood, a baffle 4 is provided above the opening 3, an exhaust pipe 5 is provided at the center of the top 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 center of the bottom of the tank body for discharging the treated water.

[0023] The tank body adopts a cylindrical structure, including a cylindrical tank wall 8, an upper head 9 is fixed on the top of the tank wall 8, and a lower head 10 is fixed on the bottom of the tank wall 8. The tank wall 8, the upper head 9 and the lower head 10 enclose a sealed cavity structure, and an exhaust pipe 5 is coaxially arranged at the center position of the upper head 9, and a drain pipe 7 is coaxially arranged at the center position of the lower head 10.

[0024] Furthermore, the exhaust pipe 5 and the drain pipe 7 are both provided with valves to control their opening and closing.

[0025] A conical inner cylinder is coaxially arranged inside the tank body, and along the direction 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, and 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. Along the direction 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, wherein 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, and a rectifying plate 1 is provided in the top cylindrical section 14 as a rectification area.

[0026] 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. 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 at 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 at 8°-14°.

[0027] The upper positive cone section 13 is used as the main separation area, and the continuously shrinking cross-sectional area can increase the cyclone field intensity and accelerate the separation of oil droplets in the oily wastewater.

[0028] The bottom center of the inverted cone 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.

[0029] 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.

[0030] The top cylindrical section 14 of the conical inner cylinder is equipped with a rectifying plate 1, the outer circumferential surface of the rectifying plate 1 is fixed to the inner circumferential surface of the top cylindrical section 14, the rectifying plate 1 includes a plate body, the plate body is provided with a plurality of channels extending in a direction parallel to the axis of the conical inner cylinder. In the present embodiment, the rectifying plate 1 includes a frame, the frame has a plurality of parallel partitions, 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 rectifying plate 1 may be arranged in the form of a porous plate, a concentric plate or a serpentine plate, and those skilled in the art may arrange them according to actual needs.

[0031] The rectifying plate 1 can hinder the rotational flow of the fluid at the top of the conical inner cylinder, convert 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 vortices 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.

[0032] 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.

[0033] 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 parallelly distributed along 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 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 coaxially arranged 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.

[0034] The vertical sleeve 19 is connected to a plurality of first water distribution pipes 20, and the water outlet end of the upwardly bent section of the first water inlet pipe 16 is connected to a plurality of 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 cylinder, and are staggered at equal intervals along the circumferential direction of the conical inner cylinder. 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 cylinder.

[0035] 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. The liquid outlet end of the first water distribution pipe 20 is bent at 90° to allow the sewage to flow out along the tangential direction of the conical inner tube.

[0036] 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.

[0037] 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. Technical personnel in this field can set it according to actual needs.

[0038] 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 extending 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, thereby ensuring uniformity of water distribution.

[0039] The water inlet method adopted in this embodiment avoids complicated 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 and realize uniform water and gas 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.

[0040] 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, and the flow of the first water inlet pipe 16 and the second water inlet pipe 17 can be adjusted 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 under 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.

[0041] 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. 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 a better treatment effect. Finally, the treated water is discharged from the tank through the drain pipe 7.

[0042] Furthermore, the coalescing plate 23 is disposed between the upper portion of the upper positive 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.

[0043] In this embodiment, the agglomeration plate 23 is made of random agglomeration filler, and its thickness is not less than 30 mm, which meets the filtering requirements. The random agglomeration filler can be made of existing materials, which will not be described in detail here. In other embodiments, the agglomeration plate 23 can be made of regular agglomeration filler, and those skilled in the art can set it according to actual needs.

[0044] 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.

[0045] Furthermore, a manhole 24 is provided on the tank wall 8 of the tank body at a position corresponding to the coalescing plate 23, so that the staff can observe the internal conditions of the tank body.

[0046] An oil-gas separation mechanism is disposed above the conical inner cylinder, and the oil-gas separation mechanism includes an oil collecting hood 2. The oil collecting hood 2 is an upwardly convex arc structure, and the curvature thereof can be determined according to actual conditions, which will not be described in detail here.

[0047] 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.

[0048] 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.

[0049] An opening 3 is coaxially arranged at the center of the oil collecting hood 2 , and the opening 3 connects the space above and below the oil collecting hood 2 .

[0050] A baffle 4 is coaxially arranged above the opening 3. Preferably, the baffle 4 is a circular baffle. In other embodiments, the baffle 4 may also be a square plate or a plate of other shapes, and its area needs to meet the requirement of blocking the oil phase.

[0051] The circular baffle is fixedly connected to the top ends of the plurality of legs 25 , and the bottom ends of the legs 25 are fixed to the upper surface of the oil collecting hood 2 .

[0052] The plurality of supporting feet 25 are evenly spaced along the circumferential direction of the circular baffle. Preferably, four supporting feet 25 are provided.

[0053] 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.

[0054] 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, and the oil drain pipe 6 is arranged along the radial direction of the tank body. The lower part of the oil drain pipe 6 is flush with the bottom edge of the oil collecting hood 2.

[0055] After the oily wastewater passes through the conical inner cylinder for cyclone flotation separation, the light components such as air bubble oil droplet adherents rise to the bottom surface of the oil collecting hood 2. As the light components such as the accumulated adherents increase continuously, the adherents finally flow to the collection area above the oil collecting hood 2 through the opening 3. 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, thereby realizing oil and gas separation and avoiding the discharge of gas and treated oil together.

[0056] 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 gauge or an ultrasonic level gauge. The electromagnetic waves emitted by the radar level gauge or the sound waves emitted by the ultrasonic level gauge have a certain penetrating performance and can pass through the oil collecting hood 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.

[0057] In this embodiment, the installation position of the radar level gauge or ultrasonic level gauge on the upper end cap 9 should be staggered with the position of the conical inner cylinder so that the radar level gauge or ultrasonic level gauge can detect the water level of the purified water outside the conical inner cylinder. At the same time, the radar level gauge or ultrasonic level gauge can also monitor the oil level above the oil collecting hood 2.

[0058] By setting the liquid level detection element 26 and the control valve 22, the liquid level in the tank is controlled.

[0059] 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 just above the conical inner cylinder and 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.

[0060] The working method of the oily wastewater treatment device of this embodiment is: 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 performs a rotating upward motion 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 the oil droplets in the wastewater. When the light components such as bubbles and oil droplets adherents gradually rise to the position of the rectifying plate 1 at the top of the conical inner cylinder, the multiple channels of the rectifying plate 1 can convert the spiral motion of the fluid into a stable axial flow, providing flow conditions for the stable separation of the external space. The light components such as bubbles and oil droplets adherents that have been rectified rise to the bottom surface of the oil collecting hood 2. As the light components such as adherents gathered on the bottom surface of the oil collecting hood 2 continue to increase, the light components such as adherents finally flow into the collection area through the opening 3 on the oil collecting hood 2. The oil phase in the adherents falls to the upper surface of the oil collecting hood 2 under the action of the baffle 4 and slides down along the upper surface of the oil collecting hood 2, and is discharged through the oil drain pipe 6 fixed on the tank body and flush with the bottom of the oil collecting hood 2, and the gas phase in the adherents is discharged through the exhaust pipe 5 at the center of the upper head 9. Impurities such as solid particles with a higher density in the conical inner cylinder slide down along the inner wall of the conical inner cylinder and gather in the inverted cone collection bin, and are regularly discharged through the sewage pipe 15. The treated purified water flows out from the top of the conical inner cylinder and enters the outer space of the conical inner cylinder. When it flows through the coalescing plate 23, it is filtered again to further reduce the oil concentration in the purified water, and finally discharged from the drain pipe 7 in the center of the lower head 10.

[0061] 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 drain pipe 15. The sewage treatment device of this embodiment can clean and maintain 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.

[0062] The oily wastewater treatment device of this embodiment can be applied to the treatment of oily wastewater in oil fields and petrochemical industries, and can also be applied to the treatment of oily wastewater in daily life and oily wastewater generated in other industrial production processes, which will not be described in detail here.

[0063] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for treating oily wastewater based on the coordination of cyclone, flotation and coalescence, characterized in that: include: The tank body has 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, and a coalescing plate is provided between the conical inner cylinder and the tank body; 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 upwardly 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 provided on the top of the tank body, and the bottom of the collection area is connected to the oil drain pipe provided on the side of the tank body.

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

3. The oily wastewater treatment device based on cyclone, flotation and coalescence coordination as claimed in 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 cyclone, flotation and coalescence coordination as claimed in claim 1 is characterized in that: The thickness of the agglomeration plate is not less than 30 mm.

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

6. The oily wastewater treatment device based on cyclone, flotation and coalescence coordination as claimed in claim 1, characterized in that: 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 a 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 circumferential direction of the conical inner cylinder.

7. The oily wastewater treatment device based on cyclone, flotation and coalescence coordination as claimed in claim 6, characterized in that: The first water inlet pipe and the second water inlet pipe are both provided with control valves.

8. The oily wastewater treatment device based on cyclone, flotation and coalescence coordination 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°.

9. The oily wastewater treatment device based on cyclone, flotation and coalescence coordination as claimed in claim 1, characterized in that: A rectifying plate is arranged on the top of the conical inner cylinder, and a plurality of channels extending in a direction parallel to the axis of the conical inner cylinder are arranged on the rectifying plate.

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

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