Rotational flow air flotation device for oil field water treatment

Abstract

The invention belongs to the technical field of oilfield produced water treatment, and particularly relates to a rotational flow air flotation device for oilfield water treatment, the device comprises a tank body, a rotational flow air flotation cover, a water distributor, an oil discharge mechanism and an air-soluble water mechanism, an annular cavity and a spiral injection groove are arranged in a nozzle of the water distributor, so that gas in air-soluble water can be controlled to be released and rotational flow is enhanced, and the water-soluble water is discharged from the tank body. The oil discharge mechanism comprises an assembly with a spiral scraper blade and a central vertical rod containing an oleophylic and hydrophobic material, the assembly and the central vertical rod are used for guiding high-viscosity oil sludge to be discharged and collecting light oil respectively, and a shock absorber comprising a piston and a gas spring is installed on a connecting pipeline of the gas-soluble water mechanism so as to relieve fluid pulse; an adjusting structure composed of a cone and a gas spring is arranged in the purified water outlet pipe, the device can cope with the problems of flash evaporation of produced water, slug flow impact, high-viscosity oil accumulation and vortex core swinging, and stable and efficient separation of oil, water and mud is achieved.

Description

Technical Field

[0001] This invention relates to the field of oilfield produced water treatment technology, and in particular to a vortex air flotation device for oilfield water treatment. Background Technology

[0002] Oilfield extraction generates large amounts of oilfield water, which contains pollutants such as crude oil, suspended solids, and mechanical impurities. Direct discharge would severely pollute the surrounding soil and water environment. Recycling requires advanced treatment to remove pollutants and meet standards for subsequent use or discharge. Cyclone flotation technology, a highly efficient solid-liquid and liquid-liquid separation technology, is widely used in oilfield water treatment. Its core principle is to combine the centrifugal force generated by cyclone flow with the buoyancy generated by flotation to separate pollutants from the water, thereby purifying the water.

[0003] Currently, existing cyclone flotation devices for oilfield water treatment still have many shortcomings in practical applications: 1. In the mixing process of dissolved water and oilfield water, the dissolved water often fails to form a stable spiral flow, resulting in insufficient contact between the microbubbles precipitated from the dissolved water and the fine oil droplets and suspended solids in the oilfield water. This makes it difficult for some fine contaminants to adhere and coalesce, affecting the separation effect. Furthermore, during the spraying process, the dissolved gas is prone to sudden flash evaporation, causing gas explosions. This not only disrupts the stability of the swirling flow field but may also impact the internal structure of the equipment, shortening its service life. 2. Most existing devices employ a single oil discharge structure, which cannot separate the viscous sludge and light oil into distinct stages. The viscous sludge easily clogs the discharge channels, leading to poor oil discharge. Furthermore, after the light oil and sludge are discharged together, a secondary separation process is required, increasing subsequent processing steps and costs. In addition, although some devices are equipped with a staged oil discharge structure, the discharge efficiency is low, and sludge accumulates on the inner wall of the top of the device, making it difficult to clean. Long-term use will further affect the separation effect. 3. Existing aerosolized water mechanisms produce uneven concentrations of aerosolized water, and pulse flow is prone to occur during transport, leading to unstable flow rates of aerosolized water entering the device, disrupting the angular velocity of the swirling field, and affecting separation efficiency. Furthermore, the aerosolized water mechanism lacks an effective gas replenishment mechanism; when the gas inside the device is insufficient, it cannot be replenished in time, resulting in a reduction in microbubble generation and further decreasing the separation effect. 4. The existing equipment lacks an adaptive adjustment structure at the purified water outlet. When the oilfield water inflow fluctuates, the internal liquid level is prone to drastic changes. An excessively high liquid level can cause incompletely separated contaminants to be discharged with the purified water, affecting the effluent quality; an excessively low liquid level may damage the internal air seal, affecting the stability of the cyclone flotation process. Furthermore, during the cyclone separation process, impurities tend to accumulate at the bottom of the existing equipment, making complete removal difficult. Long-term accumulation can clog the purified water outlet, affecting the normal operation of the equipment. Summary of the Invention

[0004] This invention addresses the problems in existing cyclone flotation devices for oilfield water treatment, such as flash vapor explosion of dissolved air damaging the cyclone field, ungraded oil discharge leading to blockage and requiring secondary treatment, pulse disturbance of dissolved air affecting cyclone stability, and liquid level fluctuations impacting effluent quality and cyclone stability. Based on conventional cyclone dissolved air flotation devices, this invention simultaneously improves four aspects of the cyclone flotation device: water distribution, oil discharge, dissolved air water delivery, and purified water effluent. It organically combines a controlled flash vaporization mechanism to enhance cyclone flow in the water distributor nozzles, a sludge guide and light oil adsorption mechanism for graded oil discharge, a pulse buffer mechanism in the dissolved air water pipeline, and an adaptive liquid level stabilization mechanism at the purified water outlet. This achieves the effect of simultaneously solving four problems—flash vaporization, slug flow impact, high-viscosity oil accumulation, and vortex core oscillation—with a single device, thus proposing a cyclone flotation device for oilfield water treatment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A cyclone flotation device for oilfield water treatment includes a base plate, a tank, a cyclone flotation hood, a water distributor, a first oil discharge assembly, a second oil discharge assembly, and an aerosol water mechanism. The tank is supported above the base plate by legs. An annular baffle is fixed inside the tank. The swirling air flotation hood is fixedly connected to the bottom of the annular baffle and its top opening is aligned with the center hole of the annular baffle. The tank is equipped with a sewage inlet pipe, a sewage outlet pipe and a clean water outlet pipe. The water distributor is installed inside the tank and located within the vortex air flotation hood. The water distributor includes an L-shaped tube, a water distribution plate, multiple arc-shaped water distribution pipes, and nozzles. The L-shaped tube penetrates the side wall of the tank. The water distribution plate is fixedly connected to the end of the L-shaped tube. The multiple arc-shaped water distribution pipes are distributed along the outer periphery of the water distribution plate and are connected to it. Each arc-shaped water distribution pipe has a nozzle at its end. The spray direction of the nozzle is tangential to the inner wall of the vortex air flotation hood, so that the dissolved water is sprayed tangentially along the inner wall of the vortex air flotation hood to form a vortex. The first oil drain assembly and the second oil drain assembly are disposed at the top of the tank body and are used to drain thick sludge and light oil respectively; The aerosol water mechanism is used to provide aerosol water to the water distributor.

[0006] In one possible design, the nozzle has an annular cavity, and the nozzle outlet is connected to the annular cavity through multiple oblique holes. The annular cavity has multiple spiral ejector grooves on the side wall away from the arc-shaped water distribution pipe. When the dissolved water flows through the outlet channel of the nozzle, the dissolved gas enters the annular cavity through the inclined hole and flashes. The flash vapor is tangentially injected into the swirling air flotation hood through the spiral ejector groove to enhance the centrifugal intensity of the swirling field.

[0007] In one possible design, the first oil drain assembly includes an outer sleeve, an oil drain pipe I, a conical plate I, multiple spiral scrapers, and an oil drain pipe II; The outer sleeve is fixedly inserted through the top of the tank body, the oil drain pipe I is coaxially fixed inside the outer sleeve and its bottom end extends downward, the conical plate I is connected between the inner wall of the outer sleeve and the outer wall of the oil drain pipe I and its top outer diameter is larger than its bottom outer diameter, and the oil drain pipe II is connected to the side wall of the outer sleeve and located below the conical plate I. Multiple spiral scrapers are fixed circumferentially to the top inner wall of the tank, with their spiral direction opposite to the direction of liquid flow rotation, to guide the rotating thick sludge into the annular space between the outer sleeve and the oil drain pipe I.

[0008] In one possible design, the second oil drain assembly includes the oil drain pipe I, multiple fixing rods, and a hollow upright; Multiple fixing rods are fixed to the inner wall of the oil drain pipe I and are connected together to the top of the hollow upright. The hollow upright extends downward into the vortex air flotation hood and connects to the top of the water distribution plate. The hollow upright has multiple pores on its wall, and the pores are filled with oleophilic and hydrophobic materials to adsorb and guide light oil into the interior of the hollow upright and discharge it through the oil drain pipe I.

[0009] In one possible design, the dissolved water mechanism includes a dissolved air pump, a pressure stabilizing tank, a return air pipe, and a connecting pipe. The inlet end of the dissolved air pump is connected to the purified water outlet pipe and the return air pipe through a pipeline. The return air pipe is connected to the exhaust pipe at the top of the tank. The outlet end of the dissolved air pump is connected to the pressure stabilizing tank through a liquid injection pipe. The pressure stabilizing tank is connected to the L-shaped pipe of the water distributor through the connecting pipe.

[0010] In one possible design, the connecting pipe is equipped with a shock absorber, which includes a buffer tube, a piston, and a gas spring I; The buffer tube is connected to the connecting tube, the piston is slidably disposed inside the buffer tube, and the piston has multiple through holes. The gas spring I is connected between the top of the buffer tube and the piston to buffer pressure fluctuations inside the connecting tube.

[0011] In one possible design, the return gas pipe is also connected to an intake pipe for replenishing gas.

[0012] In one possible design, a conical plate II is fixed inside the tank below the spiral scraper. The top of the conical plate II is connected to the inner wall of the tank, and the bottom is connected to the top of the annular partition. The inner diameter of the top of the conical plate II is larger than the inner diameter of the bottom.

[0013] In one possible design, a disc is fixed inside the tank below the swirling air flotation hood. The disc has multiple sieve holes and divides the inner cavity of the tank. The inlet of the sewage pipe is located above the disc, and the inlet of the clean water outlet pipe is located below the disc.

[0014] In one possible design, a liquid level stabilizing mechanism is provided inside the purified water outlet pipe, the liquid level stabilizing mechanism including a fixed ring, a cone and a gas spring II; The fixing ring is fixed inside the purified water outlet pipe. It has conical grooves at its top and bottom. The cone and the conical groove at the bottom of the fixing ring are arranged opposite to each other and together define an annular water outlet gap. The gas spring II supports the cone so that the area of ​​the annular water outlet gap can be adaptively adjusted according to the pressure change at the bottom of the tank to stabilize the liquid level in the tank.

[0015] This invention not only overcomes the limitations of single optimization in existing technologies, but also achieves the synchronous maintenance of a stable angular velocity in the swirling flow field without the need for additional complex drive or control structures, thereby significantly improving the efficiency and stability of oil-water separation and reducing the cost of subsequent processing.

[0016] Beneficial effects: In this invention, the special structural design of the water distributor enables the dissolved water to form a stable spiral flow on the inner wall of the vortex air flotation hood. The water distribution plate evenly distributes the dissolved water to each arc-shaped water distribution pipe. The nozzle is tangential to the inner wall of the vortex air flotation hood, causing the dissolved water to be sprayed out tangentially. With the help of the annular cavity, oblique hole and spiral ejector groove inside the nozzle, the dissolved gas is controlled to flash evaporate. While eliminating the risk of gas explosion, the flash vapor enhances the centrifugal intensity of the vortex field, so that the microbubbles precipitated in the dissolved water can fully contact and adhere to the fine oil droplets and suspended matter in the oilfield water, thereby improving the adequacy of separation. In this invention, the oil discharge mechanism is equipped with a first oil discharge component and a second oil discharge component to achieve graded discharge of viscous sludge and light oil. The spiral scraper in the first oil discharge component can intercept the sludge on the inner wall of the top of the tank and guide it to the central gap, where it is discharged through the conical plate I and the oil discharge pipe II, thus preventing the sludge from clogging the oil discharge channel. The hollow vertical rod in the second oil discharge component can fix the vortex core of the swirling flow field, effectively suppressing the emulsion backflow. The oleophilic and hydrophobic material in the pores can quickly adsorb the light oil and aggregate it for discharge, eliminating the need for secondary separation, reducing processing steps, lowering processing costs, and improving oil discharge efficiency. In this invention, the shock absorber on the connecting pipe forms a fluid buffer unit through a movable piston and a gas spring I. When a pressure peak occurs in the pipeline, the piston compresses the gas spring I to store energy and temporarily accommodates a portion of the fluid, reducing the peak flow rate. When the pressure drops, the gas spring I releases energy and pushes the piston to squeeze out the stored fluid, filling the flow trough. This mechanical buffering method makes the flow rate of dissolved water entering the water distributor more stable. Stable water flow rate is an important prerequisite for maintaining a constant angular velocity of the swirling field. In this invention, the conical device inside the purified water outlet pipe and the gas spring II constitute a self-regulating flow regulation mechanism. Its regulating power comes directly from the tank bottom pressure, i.e., the liquid level height. When the inlet water flow increases, causing the liquid level to tend to rise, the increased pressure acts on the top surface of the cone, pushing it downward and widening the outlet gap, instantly enhancing the drainage capacity and thus suppressing the rise in liquid level. Conversely, when the inlet water decreases, the pressure decreases, and the gas spring II pushes the cone upward, narrowing the outlet gap, reducing the drainage volume, and preventing the liquid level from becoming too low. This regulation is continuous, automatic, and requires no external energy. It helps maintain the stability of the working liquid level inside the tank. A stable liquid level is important for the accumulation of the upper oil layer and the consistency of the discharge operation.

[0017] In this invention, the water distributor nozzle utilizes flash vapor to enhance swirling flow and eliminate the risk of gas explosion; the spiral scraper in the oil discharge assembly forcibly reverses the direction of sludge movement, and the hollow vertical rod eliminates vortex core oscillation, achieving effective discharge of sludge and light oil; the shock absorber in the dissolved water mechanism maintains swirling flow stability and protects the internal structure; the purified water outlet pipe adaptively stabilizes the liquid level and prevents gas seal damage, thus improving the overall oil-water separation effect in oilfield water treatment, reducing treatment costs, and enhancing the stability and reliability of the device. Attached Figure Description

[0018] Figure 1 A three-dimensional structural schematic diagram of a cyclone flotation device for oilfield water treatment provided by the present invention; Figure 2 A cross-sectional structural schematic diagram of the tank body of a cyclone flotation device for oilfield water treatment provided by the present invention; Figure 3A three-dimensional exploded structural diagram of the annular partition, swirling air flotation hood, and disc of a swirling air flotation device for oilfield water treatment provided by the present invention; Figure 4 A three-dimensional structural schematic diagram of the pressure stabilizing tank, dissolved air pump, and three-way pipe of a cyclone flotation device for oilfield water treatment provided by the present invention; Figure 5 A three-dimensional structural schematic diagram of the water distributor of a cyclone flotation device for oilfield water treatment provided by the present invention; Figure 6 This is a first-view three-dimensional cross-sectional structural diagram of the nozzle of a cyclone flotation device for oilfield water treatment provided by the present invention. Figure 7 This is a second-view three-dimensional cross-sectional structural diagram of the nozzle of a vortex air flotation device for oilfield water treatment provided by the present invention. Figure 8 A three-dimensional cross-sectional view of the outer sleeve and oil drain pipe I of a cyclone flotation device for oilfield water treatment provided by the present invention; Figure 9 A three-dimensional cross-sectional structural schematic diagram of the shock absorber of a cyclone flotation device for oilfield water treatment provided by the present invention; Figure 10 This is a three-dimensional cross-sectional view of the purified water outlet pipe and the fixing ring of a cyclone flotation device for oilfield water treatment provided by the present invention. Figure 11 This is a physical image of a cyclone flotation device for oilfield water treatment provided by the present invention.

[0019] In the diagram: 1. Base plate; 2. Tank body; 3. Support leg; 4. Sewage inlet pipe; 5. Annular baffle; 6. Swirl flotation hood; 7. Disc; 8. Screen hole; 9. Clean water outlet pipe; 10. Sewage pipe; 11. Water distributor; 12. L-shaped pipe; 13. Water distribution tray; 14. Arc-shaped water distribution pipe; 15. Nozzle; 16. Annular cavity; 17. Inclined hole; 18. Spiral ejector groove; 19. Outer sleeve; 20. Oil drain pipe I; 21. Conical plate I; 22. Spiral scraper; 23. Oil drain pipe II; 24. 25. Fixed rod; 26. Hollow upright; 27. Hollow hole; 28. Exhaust pipe; 29. ​​Mounting plate; 20. Dissolved gas pump; 31. Pressure stabilizing tank; 32. T-connector; 33. Return gas pipe; 34. Liquid injection pipe; 35. Air inlet pipe; 36. Connecting bracket; 37. Connecting pipe; 38. Shock absorber; 39. Buffer pipe; 40. Piston; 41. Through hole; 42. Gas spring I; 43. Fixed ring; 44. Conical groove; 45. Cross bracket; 46. Gas spring II; 47. Cone; 48. Conical plate II. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] In one embodiment: Refer to Figure 1 A vortex air flotation device for oilfield water treatment relates to the field of oilfield produced water treatment technology. It mainly includes a base plate 1, which is made of steel plate and provides a stable foundation for the entire device. The base plate 1 is placed horizontally on the ground or platform. The tank body 2 is a vertical cylindrical structure made of carbon steel. Multiple support legs 3 are welded to the outer wall of the tank body 2. The number of support legs 3 can be three or four, which are evenly distributed around the circumference of the tank body 2. The bottom end of the support legs 3 is processed into a flat support surface and placed directly on the top of the base plate 1. This support method facilitates installation and centering.

[0022] Furthermore, referring to Figure 1 and Figure 2 A sewage inlet pipe 4 is provided on the lower side of the tank body 2. The sewage inlet pipe 4 is horizontally inserted into the tank body 2. The opening direction of the end of the sewage inlet pipe 4 is tangent or nearly tangent to the wall of the tank body 2. This arrangement allows the oilfield water to generate an initial swirling tendency after entering the tank body 2. Below the sewage inlet pipe 4, a drain pipe 10 is provided on the same side of the tank body 2. The drain pipe 10 is used to discharge solid impurities and heavy sludge deposited at the bottom of the tank body 2. A valve is installed on the drain pipe 10 to control the discharge. A clean water outlet pipe 9 is fixedly connected to the center of the bottom of the tank body 2. The clean water outlet pipe 9 extends vertically downward. The treated clean water finally flows out of the device through this pipe. An opening is provided at the top of the tank body 2 for installing an oil discharge mechanism.

[0023] Furthermore, referring to Figure 2 and Figure 3 Inside the tank 2, an annular baffle 5 is fixed at a certain height from the top. The outer edge of the annular baffle 5 is welded and fixed to the inner wall of the tank 2. The center of the annular baffle 5 is a circular hole. The swirling air flotation cover 6 is fixedly connected to the bottom of the annular baffle 5. The swirling air flotation cover 6 is a conical component with a small opening at the top and a large opening at the bottom. The edge of the top opening of the swirling air flotation cover 6 is welded to the bottom of the annular baffle 5, and the center of its opening is aligned with the circular hole of the annular baffle 5. The side wall of the swirling air flotation cover 6 is a smooth curved surface to guide the fluid to form a stable swirling flow.

[0024] Furthermore, referring to Figure 2 and Figure 3Inside the tank 2 space between the vortex flotation hood 6 and the drain pipe 10, a disc 7 is fixedly installed. The disc 7 is placed horizontally, and its outer edge is sealed to the inner wall of the tank 2. Multiple sieve holes 8 are evenly distributed on the disc 7. The diameter of the sieve holes 8 is smaller than the size of the solid particles that need to be intercepted. The function of the disc 7 is to block the sinking solid impurities while allowing clean water to pass through.

[0025] Furthermore, referring to Figure 2 , Figure 3 and Figure 5 The water distributor 11 is a key component for guiding the aerosolized water to generate a swirling flow. The water distributor 11 includes an L-shaped pipe 12 and a water distribution plate 13. One end of the L-shaped pipe 12 is fixedly inserted through the side wall of the tank 2 and extends to the outside of the tank 2 to receive aerosolized water supplied from the outside. The other end of the L-shaped pipe 12 is located inside the tank 2 and is fixedly connected to the water distribution plate 13. The water distribution plate 13 is located in the central area inside the swirling air flotation hood 6, preferably a horizontally placed disc-shaped cavity 7. Multiple arc-shaped distribution plates are fixedly connected to the outer peripheral wall of the water distribution plate 13. Water pipes 14, these arc-shaped water distribution pipes 14 are evenly distributed radially around the water distribution plate 13. Each arc-shaped water distribution pipe 14 has a nozzle 15 fixedly installed at its end. The water outlet direction of the nozzle 15 is set so that the water jet is tangential to the inner wall of the vortex air flotation hood 6. When the dissolved water enters the water distribution plate 13 from the L-shaped pipe 12, it will be evenly distributed to each arc-shaped water distribution pipe 14 and finally sprayed out tangentially from each nozzle 15, impacting the inner wall of the vortex air flotation hood 6, thereby forming a strong rotating water flow inside the vortex air flotation hood 6.

[0026] Furthermore, referring to Figure 5 and Figure 6The outlet axis of nozzle 15 is parallel to the tangent direction of the inner wall of the swirl flotation hood 6. This causes the high-speed aerosol water jet ejected from nozzle 15 to move closely along the inner wall of the swirl flotation hood 6, thereby generating a strong forced swirling flow inside the hood. An annular cavity 16 surrounding the outlet channel is provided inside nozzle 15. The annular cavity 16 is connected to the main outlet channel of nozzle 15 through multiple oblique holes 17. The axial direction of the oblique holes 17 forms a certain angle with the axial direction of the main outlet channel. On the inner wall of the annular cavity 16 away from the connection end of the arc-shaped water distribution pipe 14, multiple spiral ejector grooves 18 are provided. One end of the spiral ejector groove 18 leads into the interior of the annular cavity 16, and the other end extends to the side wall of nozzle 15. The outlet end of the spiral ejector groove 18 is equipped with a dirt-proof sealing sleeve to prevent sludge from entering the annular cavity 16. When the high-pressure dissolved water flows through the main outlet channel of the nozzle 15 at high speed, due to the local pressure drop, the dissolved gas will preferentially enter the annular cavity 16 through the inclined hole 17. In the relatively independent volume space of the annular cavity 16, the dissolved gas can be controlled to flash evaporate and expand. The expanded gas then passes through the spiral ejector groove 18 and is injected into the vortex air flotation cover 6 in the form of a high-speed tangential jet. This process not only avoids the gas explosion or vibration that may be caused by the instantaneous expansion of gas in the main water channel, but also the high-speed tangential gas jet further enhances the angular velocity and centrifugal force intensity of the vortex field.

[0027] Furthermore, referring to Figure 2 and Figure 8 The oil discharge mechanism is integrated at the top of the tank body 2. The first oil discharge component is responsible for handling high-viscosity, easily accumulated sludge. The outer sleeve 19 is a vertically installed cylinder, the lower end of which passes through the top plate of the tank body 2 and is fixedly sealed thereto. The oil discharge pipe I20 is coaxially installed inside the outer sleeve 19. The upper end of the oil discharge pipe I20 extends outside the tank body 2, and the lower end extends below the lower opening of the outer sleeve 19, penetrating deep into the internal space of the tank body 2. In the annular space between the inner wall of the outer sleeve 19 and the outer wall of the oil discharge pipe I20, a conical plate I21 is fixedly installed. The large end of the conical plate I21 faces upward and the small end faces downward, forming an inverted shape. The funnel-shaped cone plate I21 is sealed to the inner wall of the outer sleeve 19 and the outer wall of the oil drain pipe I20. On the side wall of the outer sleeve 19, below the cone plate I21, an opening is made and connected to the oil drain pipe II23. The oil drain pipe II23 extends outward horizontally or obliquely. On the inner surface of the top plate of the tank body 2, with the axis of the tank body 2 as the center, multiple spiral scrapers 22 are fixed. The spiral scrapers 22 are spiral curved and extend from near the inner wall of the tank body 2 toward the outer sleeve 19 at the center. The spiral directions of all the spiral scrapers 22 are opposite to the swirling directions inside the swirling air flotation hood 6.

[0028] Furthermore, referring to Figure 2 and Figure 8The second oil drain assembly shares some structures with the first oil drain assembly. Multiple fixing rods 24 are evenly distributed and fixed to the inner wall of the oil drain pipe I 20 along the circumference. Their inner ends are jointly fixed to a hollow upright rod 25. The hollow upright rod 25 is a slender round tube, and its axis coincides with the axis of the tank body 2. The upper end of the hollow upright rod 25 is supported inside the oil drain pipe I 20 by the fixing rods 24. The lower end of the hollow upright rod 25 extends downward, passes through the central area of ​​the vortex air flotation hood 6, and is finally fixedly connected to the top center of the water distribution plate 13. The outer side of the hollow upright rod 25... The filter wall is processed or has numerous tiny pores 26. The size of the pores 26 allows the oil phase to pass through but effectively blocks the water phase. These pores 26 are filled or coated with an oleophilic and hydrophobic material, which can be polypropylene fiber, surface-treated metal felt, or a specific polymer coating. The hollow upright 25 works by occupying the central region of the vortex core when a low-pressure vortex core forms at the center of the swirling flow field, thus physically limiting the radial oscillation range of the vortex core and stabilizing the flow field. The oleophilic and hydrophobic material in the pores 26 is a replaceable or regenerable filler (e.g., using a modular filter design). When the adsorption efficiency decreases, it can be replaced or cleaned by disassembling the oil drain pipe I 20 or the water distribution plate 13. Those skilled in the art should understand that this material needs to be checked and maintained regularly according to water quality and treatment volume to ensure the separation efficiency of the device during continuous operation.

[0029] Furthermore, referring to Figure 1 , Figure 2 and Figure 4 The dissolved air mechanism provides a microbubble source for the entire system. Mounting plate 28 is fixed to base plate 1, providing a mounting base for dissolved air pump 29. Dissolved air pump 29 is a booster pump capable of efficiently dissolving gas into liquid. Multiple connecting brackets 35 are welded to the outer wall of tank 2, collectively supporting pressure stabilizing tank 30. Pressure stabilizing tank 30 is a pressure vessel used to store and buffer water containing dissolved gas. Exhaust pipe 27 extends from the top of tank 2 to release any excess gas that may accumulate or to maintain pressure balance at the top of the tank. The upper end of exhaust pipe 27 is connected to return pipe 32 via a pipe. The other end of return pipe 32... The end is connected to a three-way valve, and the lower end of the purified water outlet pipe 9 is connected to a three-way pipe 31. One outlet of the three-way pipe 31 is also connected to the three-way valve through a pipe. The outlet of the three-way valve is connected to the inlet of the dissolved air pump 29 through a pipe. In this way, a portion of the purified water discharged from the purified water outlet pipe 9 can be mixed with the gas from the exhaust pipe 27 and enter the dissolved air pump 29 together. The outlet of the dissolved air pump 29 is connected to the inlet of the pressure stabilizing tank 30 through the injection pipe 33. The outlet of the pressure stabilizing tank 30 is connected to the inlet of the L-shaped pipe 12 on the side wall of the tank body 2 through the connecting pipe 36. A shock absorber 37 is installed in series on the connecting pipe 36.

[0030] Furthermore, referring to Figure 4 and Figure 9The damper 37 has a buffer tube 38 that is a vertically placed T-shaped short tube. The lower end of the buffer tube 38 is connected to the connecting tube 36. The piston 39 is installed inside the buffer tube 38 and can slide up and down along the inner wall of the tube. The outer peripheral wall of the piston 39 is provided with a wear-resistant sealing ring. The two ends of the buffer tube 38 are provided with dustproof sealing gaskets. The piston 39 has multiple through holes 40 to allow fluid to pass slowly. Multiple gas springs I 41 are installed between the top inner wall of the buffer tube 38 and the top of the piston 39. The cylinder of the gas spring I 41 is fixed to the top inner wall of the buffer tube 38. The piston rod is connected downward to the piston 39. The parameters of the gas spring I 41 are set according to the system working pressure. When the pressure inside the connecting tube 36 is stable, the piston 39 is in a balanced position under the preload of the gas spring I 41. The fluid mainly flows through the main channel of the connecting tube 36 and a small amount flows through the through holes 40 of the piston 39.

[0031] Furthermore, referring to Figure 4 An air inlet pipe 34 is connected to the return air pipe 32. The air inlet pipe 34 is connected to an external air source. An electromagnetic control valve is installed on the air inlet pipe 34 and is electrically connected to the controller. A pressure sensor is installed on the top of the tank 2 and is electrically connected to the controller. When the pressure sensor detects that the pressure at the top of the tank 2 is lower than 0.1 MPa (pressure value is only an example), the controller controls the electromagnetic control valve to open and replenish gas into the return air pipe 32 until the pressure at the top of the tank 2 reaches 0.3 MPa (pressure value is only an example), at which point the electromagnetic control valve closes.

[0032] Furthermore, referring to Figure 2 Conical plate II 47 is fixedly installed inside tank body 2, located below spiral scraper 22. The upper end of conical plate II 47 is larger and the lower end is smaller. Its lower edge is sealed to the top of annular partition 5, and an annular channel is formed between conical plate II 47 and the inner wall of tank body 2.

[0033] The dissolved air water mechanism includes a controller (such as a PLC), a dissolved air pump 29, a pressure stabilizing tank 30, a return air pipe 32, and a connecting pipe 36. The controller is electrically connected to the dissolved air pump 29 to control the start, stop, and speed of the dissolved air pump 29. The liquid inlet of the dissolved air pump 29 is connected to the purified water outlet pipe 9 and the return air pipe 32 through a pipeline. The return air pipe 32 is connected to the exhaust pipe 27 at the top of the tank body 2. The liquid outlet of the dissolved air pump 29 is connected to the pressure stabilizing tank 30 through the liquid injection pipe 33. The pressure stabilizing tank 30 is connected to the L-shaped pipe 12 of the water distributor 11 through the connecting pipe 36.

[0034] In another embodiment: Refer to Figure 2 and Figure 10Inside the purified water outlet pipe 9, the fixing ring 42 is fixed to the pipe wall by a support rib. Its upper and lower end faces are also machined with conical grooves 43, which are tapered holes that are larger at the top and smaller at the bottom. A cross bracket 44 is fixed inside the purified water outlet pipe 9 below the fixing ring 42. The cylinder of the gas spring II 45 is fixed at the center of the cross bracket 44. A protective sleeve is fitted over the gas spring II 45, allowing the area of ​​the annular water outlet gap to adaptively adjust with changes in the pressure at the bottom of the tank 2, thus stabilizing the liquid level inside the tank. The piston rod of the gas spring II 45 extends vertically upwards, with a cone 46 fixed to its top. A guide rod is provided at the bottom of the cone 46, and a corresponding guide hole is provided on the cross bracket 44. The guide rod slides through the guide hole to limit and guide the movement of the cone 46. The conical surface of the cone 46 is matched with the conical surface of the conical groove 43 below the fixing ring 42. The outer peripheral wall of the cone 46 is provided with an anti-stick coating, and the inner wall of the conical groove 43 of the fixing ring 42 is provided with a wear-resistant sealing ring. Under the push of the gas spring II 45, the top of the cone 46 can abut against or approach the conical groove 43 at the bottom of the fixing ring 42, forming an annular water passage gap. The parameters of the gas spring II 45 are set according to the normal working liquid level pressure of the tank 2. When the liquid level pressure changes, the force acting on the top surface of the cone 46 changes accordingly, pushing the cone 46 to move, thereby changing the size of the annular water outlet gap.

[0035] A method for using a cyclone flotation device for oilfield water treatment includes the following steps: S1. First, open the relevant valves and inject the oilfield water to be treated into the tank 2 through the sewage inlet pipe 4. After the oilfield water enters the tank 2, it falls on the outside of the annular baffle 5 and the vortex air flotation cover 6 and gradually accumulates to a certain level. At the same time, start the dissolved air pump 29. The dissolved air pump 29 draws part of the clean water discharged from the bottom of the tank 2 through the three-way pipe 31 and draws the gas discharged from the exhaust pipe 27 at the top of the tank 2 through the return air pipe 32. If the gas is insufficient, external gas can be added to the dissolved air pump 29 through the air inlet pipe 34. The dissolved air pump 29 mixes the clean water and air thoroughly to prepare aerosol water. The aerosol water is transported to the pressure stabilizing tank 30 for storage through the liquid injection pipe 33. The pressure stabilizing tank 30 performs pressure stabilization treatment on the aerosol water to ensure that the pressure and flow rate of the aerosol water are stable. S2. After pressure stabilization, the aerosolized water is transported to the L-shaped pipe 12 through the connecting pipe 36. If a high-pressure blockage occurs in the connecting pipe 36, the piston 39 in the buffer pipe 38 will move upward under the action of fluid pressure, compressing the air spring I 41, absorbing the hydraulic impact energy, and reducing pressure. When the fluid pressure decreases, the air spring I 41 rebounds, pushing the piston 39 to squeeze the stored aerosolized water back into the connecting pipe 36, maintaining a stable flow rate of aerosolized water. The aerosolized water enters the water distribution plate 13 through the L-shaped pipe 12. The water distribution plate 13 evenly distributes the aerosolized water to each arc-shaped water distribution pipe 14. The aerosolized water flows along the arc-shaped water distribution pipe 14 to the nozzle 15, and is tangentially sprayed from the nozzle 15 to the inner wall of the swirl air flotation hood 6. S3. When the dissolved water enters the outlet channel inside the nozzle 15, the dissolved gas preferentially enters the annular cavity 16 through the inclined hole 17 for controlled flash evaporation. The gas after flash evaporation expands in the annular cavity 16 and is injected tangentially into the swirl flotation hood 6 at high speed through the spiral ejector groove 18, which enhances the centrifugal intensity of the swirl field and eliminates the risk of gas explosion. The dissolved water ejected from the nozzle 15 flows spirally along the inner wall of the swirl flotation hood 6, forming a stable swirl field. During the swirl process, the dissolved water is fully mixed with the oilfield water outside the swirl flotation hood 6, and a low-pressure annular area is formed inside the tank 2. The air in the dissolved water precipitates a large number of microbubbles under the low-pressure environment. S4. During the rising process, microbubbles come into full contact with and attach to the fine oil droplets and suspended matter in the oilfield water, forming air flocs with a density less than that of water. Under the combined action of centrifugal force and buoyancy, the air flocs flow upward, achieving initial separation from the water. The mixture continues to flow upward under the action of swirling flow, and is guided by the cone plate II47 to avoid turbulence in the mixture. S5. In the rising air floc, the thick sludge carries tangential rotational kinetic energy and comes into contact with the spiral scraper 22 on the inner wall of the top of the tank 2. Since the spiral scraper 22 is stationary and rotates in the opposite direction to the sludge, the sludge is intercepted by the spiral scraper 22. Under the guidance of the spiral scraper 22 and the push of the subsequent fluid, the sludge slides along the spiral scraper 22 toward the center and enters the gap between the outer sleeve 19 and the oil drain pipe I 20. Under the guidance of gravity and the inclined surface of the conical plate I 21, the sludge is discharged to the outside through the oil drain pipe II 23, thus completing the separation and discharge of the thick sludge. S6. Light oil has a lower density and continues to flow upward. Since the oil drain pipe I20 extends below the outer sleeve 19 and further below the thick sludge, the light oil that continues to flow upward is discharged through the oil drain pipe I20. In addition, during the oil swirling process, it converges towards the center and contacts the outer wall of the hollow vertical rod 25. The hollow vertical rod 25 is inserted into the center of the swirling field, which helps to suppress the violent oscillation of the vortex core and reduce the fluid turbulence in the central region. This provides structural conditions for reducing the back mixing of the emulsion. Under the action of centrifugal force, the tiny oil droplets move towards the center and are adsorbed and aggregated into an oil film by the oleophilic and hydrophobic material in the pores 26 of the hollow vertical rod 25. The oil film flows upward along the inner wall of the hollow vertical rod 25 and enters the oil drain pipe I20. It is then discharged to the outside through the oil drain pipe I20, completing the separation and discharge of the light oil. S7. The separated purified water flows outward under the action of centrifugal force and then flows downward under the action of gravity. It passes through the sieve hole 8 of the disc 7. The disc 7 intercepts the impurities remaining in the water. The impurities accumulate on the top of the disc 7 and are periodically discharged through the drain pipe 10. The purified water flows downward through the sieve hole 8 to the bottom of the tank 2 and is discharged through the purified water outlet pipe 9. S8. When the inflow of oilfield water surges, the liquid level in tank 2 rises, the bottom pressure increases, and the pressure acts on the top surface of cone 46, overcoming the elastic force of gas spring II 45 to push cone 46 downward, expanding the annular water outlet area, accelerating the discharge speed of clean water, and pulling the liquid level back to normal height. When the inflow decreases sharply, the pressure in tank 2 drops, gas spring II 45 rebounds and pushes cone 46 upward, reducing the annular water outlet area, increasing flow resistance, preventing the water in tank 2 from being pumped dry, maintaining stable gas seal, and some of the discharged clean water enters dissolved air pump 29 through three-way pipe 31 for recycling. Excess gas in tank 2 enters dissolved air pump 29 through exhaust pipe 27 and return gas pipe 32 for gas recycling. The whole process continues, completing the continuous treatment of oilfield water.

[0036] Maintenance Operation: After the unit has been running for a period of time, it should be maintained regularly (e.g., every 30 days) according to the influent water quality. Maintenance includes: thoroughly draining sediment from the bottom of the tank through the drain pipe 10; inspecting and cleaning the spiral scraper 22, the orifices 26 of the hollow upright 25, and the spiral ejector grooves 18 of the nozzle 15 to remove accumulated sludge; checking the nozzle 15 for blockage; replacing or cleaning the oleophilic and hydrophobic material inside the orifices 26 of the hollow upright 25 as needed; applying grease to the piston 39 of the shock absorber 37, the cone 46 of the liquid level stabilizing mechanism, and the guide rod to ensure smooth operation of moving parts; regularly checking the integrity of wear-resistant sealing rings and gaskets, and replacing them promptly if damaged to ensure the sealing performance and separation efficiency of the unit. Regular maintenance is a necessary condition for ensuring the long-term stable and efficient operation of the unit.

[0037] However, as is well known to those skilled in the art, the working principle and wiring method of the dissolved air pump 29 are conventional methods or common knowledge, and will not be described in detail here. Those skilled in the art can make any selections according to their needs or convenience.

[0038] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cyclone flotation device for oilfield water treatment, characterized in that, Includes a base plate (1), a tank (2), a swirling air flotation hood (6), a water distributor (11), a first oil discharge assembly, a second oil discharge assembly, and an air-dissolved water mechanism; The tank (2) is supported above the base plate (1) by the support legs (3). An annular partition (5) is fixed inside the tank (2). The swirling air flotation cover (6) is fixedly connected to the bottom of the annular partition (5) and its top opening is aligned with the center hole of the annular partition (5). The tank (2) is provided with a sewage inlet pipe (4), a sewage outlet pipe (10) and a clean water outlet pipe (9). The water distributor (11) is installed inside the tank (2) and located in the vortex air flotation hood (6). The water distributor (11) includes an L-shaped pipe (12), a water distribution plate (13), multiple arc-shaped water distribution pipes (14) and a nozzle (15). The L-shaped pipe (12) penetrates the side wall of the tank (2). The water distribution plate (13) is fixedly connected to the end of the L-shaped pipe (12). Multiple arc-shaped water distribution pipes (14) are distributed along the outer periphery of the water distribution plate (13) and connected to it. Each arc-shaped water distribution pipe (14) is provided with a nozzle (15) at its end. The spray direction of the nozzle (15) is tangential to the inner wall of the vortex air flotation hood (6) so that the dissolved water is sprayed tangentially along the inner wall of the vortex air flotation hood (6) to form a vortex. The first oil drain assembly and the second oil drain assembly are disposed on the top of the tank (2) for draining thick sludge and light oil respectively; The aerosol water mechanism is used to provide aerosol water to the water distributor (11).

2. The cyclone flotation device for oilfield water treatment according to claim 1, characterized in that, The nozzle (15) is provided with an annular cavity (16). The water outlet of the nozzle (15) is connected to the annular cavity (16) through multiple oblique holes (17). Multiple spiral ejector grooves (18) are opened on the side wall of the annular cavity (16) away from the arc-shaped water distribution pipe (14). When the dissolved water flows through the outlet channel of the nozzle (15), the dissolved gas enters the annular cavity (16) through the inclined hole (17) and flashes. The flash vapor is tangentially injected into the swirling air flotation hood (6) through the spiral ejector groove (18) to enhance the centrifugal intensity of the swirling field.

3. The cyclone flotation device for oilfield water treatment according to claim 2, characterized in that, The first oil discharge assembly includes an outer sleeve (19), an oil discharge pipe I (20), a conical plate I (21), multiple spiral scrapers (22), and an oil discharge pipe II (23); The outer sleeve (19) is fixedly inserted through the top of the tank body (2), the oil drain pipe I (20) is coaxially fixed inside the outer sleeve (19) and its bottom end extends downward, the conical plate I (21) is connected between the inner wall of the outer sleeve (19) and the outer wall of the oil drain pipe I (20) and its top outer diameter is larger than its bottom outer diameter, the oil drain pipe II (23) is connected to the side wall of the outer sleeve (19) and is located below the conical plate I (21); Multiple spiral scrapers (22) are fixed circumferentially to the top inner wall of the tank (2), with their spiral direction opposite to the direction of liquid flow rotation, to guide the rotating thick sludge to the annular space between the outer sleeve (19) and the oil drain pipe I (20).

4. The cyclone flotation device for oilfield water treatment according to claim 3, characterized in that, The second oil drain assembly includes the oil drain pipe I (20), multiple fixing rods (24), and a hollow upright (25); Multiple fixing rods (24) are fixed to the inner wall of the oil drain pipe I (20) and are connected to the top of the hollow upright (25). The hollow upright (25) extends downward into the vortex air flotation cover (6) and is connected to the top of the water distribution plate (13). Multiple pores (26) are provided on the wall of the hollow upright (25). The pores (26) are filled with oleophilic and hydrophobic materials to adsorb and guide light oil into the interior of the hollow upright (25) and discharge it through the oil drain pipe I (20).

5. The cyclone flotation device for oilfield water treatment according to claim 4, characterized in that, The dissolved water system includes a dissolved air pump (29), a pressure stabilizing tank (30), a return air pipe (32), and a connecting pipe (36). The inlet end of the dissolved air pump (29) is connected to the purified water outlet pipe (9) and the return air pipe (32) through a pipeline. The return air pipe (32) is connected to the exhaust pipe (27) at the top of the tank (2). The outlet end of the dissolved air pump (29) is connected to the pressure stabilizing tank (30) through the injection pipe (33). The pressure stabilizing tank (30) is connected to the L-shaped pipe (12) of the water distributor (11) through the connecting pipe (36).

6. The cyclone flotation device for oilfield water treatment according to claim 5, characterized in that, The connecting pipe (36) is provided with a shock absorber (37), which includes a buffer pipe (38), a piston (39) and a gas spring I (41). The buffer tube (38) is connected to the connecting tube (36), the piston (39) is slidably disposed in the buffer tube (38), the piston (39) has multiple through holes (40), and the gas spring I (41) is connected between the top of the buffer tube (38) and the piston (39) to buffer the pressure fluctuations in the connecting tube (36).

7. The cyclone flotation device for oilfield water treatment according to claim 6, characterized in that, The return pipe (32) is also connected to an intake pipe (34) for replenishing gas.

8. The cyclone flotation device for oilfield water treatment according to claim 7, characterized in that, Inside the tank (2), below the spiral scraper (22), there is a conical plate II (47). The top of the conical plate II (47) is connected to the inner wall of the tank (2), and the bottom is connected to the top of the annular partition (5). The inner diameter of its top is larger than the inner diameter of its bottom.

9. The cyclone flotation device for oilfield water treatment according to claim 8, characterized in that, Inside the tank (2), a disc (7) is fixed below the vortex air flotation hood (6). The disc (7) has multiple sieve holes (8) and the disc (7) divides the inner cavity of the tank (2). The inlet of the sewage pipe (10) is located above the disc (7), and the inlet of the clean water outlet pipe (9) is located below the disc (7).

10. A cyclone flotation device for oilfield water treatment according to claim 9, characterized in that, The purified water outlet pipe (9) is equipped with a liquid level stabilizing mechanism, which includes a fixed ring (42), a cone (46), and a gas spring II (45). The fixing ring (42) is fixed inside the purified water outlet pipe (9). It has conical grooves (43) at its top and bottom. The cone (46) is arranged opposite to the conical groove (43) at the bottom of the fixing ring (42) and together defines an annular water outlet gap. The gas spring II (45) supports the cone (46) so that the area of ​​the annular water outlet gap can be adaptively adjusted according to the pressure change at the bottom of the tank (2) to stabilize the liquid level in the tank.

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