A cyclone coupling coalescence oil-solid synergistic separation device and method

Abstract

The present application relates to the technical field of petrochemical wastewater separation and purification, in particular to a cyclone coupling coalescence oil-solid synergistic separation device and method. The present application provides a cyclone coupling coalescence oil-solid synergistic separation device, which is provided with a cyclone separation structure, an oil-water coalescence structure and a backwashing structure. The granular matter is arranged radially in a spiral direction through a volute flow channel, and the residence time of the fluid is optimized through a spiral jacket structure in the cyclone separation structure, so as to strengthen the cyclone separation effect of the solid phase pollutants. In the oil-water coalescence structure, the demulsification, adhesion, coalescence and migration of the emulsified oil droplets are strengthened through the fiber units with oleophobic and oleophilic properties. The device has stable anti-fouling performance in long-period operation, high oil-solid separation efficiency, low maintenance cost and small land occupation.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical wastewater separation and purification, and in particular to a cyclone-coupled coalescence oil-solid collaborative separation device and method. Background Art

[0002] Currently, the petrochemical industry generates large quantities of oily and solid-containing wastewater during atmospheric and vacuum decompression and catalytic processes. Recycling and treating this wastewater is a crucial component of environmental protection. Directly discharging untreated oily and solid-containing wastewater not only causes severe environmental pollution but also wastes significant amounts of oil resources. Oily wastewater comes from a wide range of sources and is complex in composition. Oils are classified by particle size range, existing in dissolved, free, and emulsified forms. Suspended matter often carries impurities such as surfactants, bacteria, and sulfides, making wastewater treatment more challenging. Given the large treatment volumes, numerous particles, and small dispersed oil droplet sizes of this wastewater, common treatment methods include gravity sedimentation, cyclonic centrifugation, electrolysis, salting-out, membrane separation, and flotation. However, achieving the required purification performance using a single separation method alone is difficult. With the increasing refinement of national environmental protection planning and guidance, researchers both domestically and internationally have been actively developing novel devices and processes that combine various separation technologies.

[0003] Compared to chemical methods, coalescence is a highly efficient, energy-efficient, and pollution-free coarse-graining technology, offering significant advantages in treating oily wastewater. Fibers are commonly used in coalescence. Fibers with varying hydrophilic and hydrophobic properties are woven into fiber units in an X or Ω pattern. These fiber units possess a large specific surface area and complex pore structures. Oil droplets, under the influence of various forces, undergo collision, interception, adsorption, and wetting, achieving a high degree of oil-water separation.

[0004] Chinese utility model CN202221224701.X provides a cyclone flotation coalescence oil remover, which includes an oil remover, a water inlet pipe and an oil removal pipe. It is equipped with two sealed boxes, the first sealed box is equipped with a mixing mechanism, and the second sealed box is equipped with a power mechanism. The device drives the sewage to mix and stir to generate bubbles through a rotating shaft and a drive shaft. The principle is to use bubbles to carry tiny oil droplets to float to achieve oil-water separation. The disadvantages are that the equipment structure is complex, there is mechanical wear when the rotating shaft is operated, the mechanical efficiency is low, and the size of the generated bubbles is difficult to control.

[0005] Chinese utility model CN201620461481.0 relates to a coalescing oil-water separation and collection device, the main body of which includes a tank body and a floating oil collection device, the tank body is equipped with a head and a cylinder body, the floating oil collection device is fixed on the head body, the cylinder body is equipped with a hydrocyclone separation bundle, a water distribution tank, a coalescing inclined plate filler and an oil discharge pipe, and a partition is provided inside the water distribution tank, which divides the water distribution tank into multiple independent spaces. The device can realize the three-phase separation treatment of oil, water and solid in oily wastewater, but the flow or pressure in each chamber of the equipment is uneven, and the rotor piston and the water distribution tank are prone to blockage.

[0006] Chinese invention CN202310530025.1 discloses a cyclone agglomeration filtration separation collector for oily wastewater, comprising a tank body, an oil collecting area, a cyclone separation device, a coarse granulation agglomeration device, a sludge collecting device, a filtering device and a sewage discharge device. The cyclone separation device comprises a cyclone separation tube partition, a fixed rod, a sludge collecting bucket, a deflector, a separation tube, an oil guide tube and a support plate, etc. The device operates from top to bottom to treat wastewater, has good operating stability, and has a certain separation effect on separating oil and muddy wastewater. However, the equipment has a complex structure and occupies a large area. The agglomeration device has no backwashing operation, and the oil sludge carried by the fiber is cleaned manually, which increases the cost.

[0007] Chinese utility model CN201720630642.9 provides a cyclone coalescence oil-water separation device. The device comprises a cyclone tank and a separator, which divides the tank's interior into a liquid inlet chamber and a liquid separation chamber. An overflow outlet is located at the top of the tank, and a water outlet is located at the bottom. By generating a strong cyclone within the cyclone chamber and utilizing the density difference between the dispersed and continuous phases, the device achieves two-phase separation. However, the separation process suffers from the problem of secondary particle entrainment, preventing coordinated oil-solid separation and making it unsuitable for high-precision applications.

[0008] Chinese invention CN202110147232.X provides a multi-stage cyclone coalescence circulating hydrogen dehydrogenator, including a tank body, a tank body inlet, a partition plate, a cyclone coalescer, a downcomer, etc. One end of the downcomer is connected to the cyclone coalescer, and the other end passes through the baffle. The tank body inlet is located at the lower part outside the tank body, the purified gas outlet is located at the top of the tank body, and the drain port is located at the bottom of the tank body. The cyclone coalescence circulating hydrogen dehydrogenator adopts a gradient graded dehydrogenation process and has a certain dehydrogenation efficiency. However, the separation process is implemented in three times, and the process is complicated. The inside of the tank body is loaded by multiple cyclone cylinders and baffles, and additional support components need to be added.

[0009] Chinese utility model CN201720047234.0 describes an oil-water separation device. The main body of the device consists of four chambers. The first two chambers are equipped with cyclones, while the second two chambers are equipped with polypropylene packing at the top and stainless steel corrugated packing at the bottom. A gas generator is installed at the bottom of the coalescence zone. The oil-containing liquid is mixed in a tubular reactor and then enters the four chambers in sequence, undergoing four separation operations. While the device has a certain separation effect, it is bulky, the second and third chambers are prone to clogging, and it requires the addition of a certain amount of surfactant, which adds additional cost.

[0010] Patent application CN201820174928.5 discloses a novel hydrocyclone coalescing degreaser. The device consists of a tank and a filter. The tank is equipped with a cyclone chamber and a packing chamber. The cyclone is connected to the sewage outlet, and the cyclone wastewater outlet is connected to the packing chamber. An oil collector is also installed on the top of the tank. This device utilizes a PLC control system. However, its disadvantages include a complex structure, numerous internal tank accessories, and poor repair and maintenance. Backwashing utilizes high-temperature steam, which can easily cause aging and damage to the piping.

[0011] Chinese invention CN201810712352.8 discloses an ultrasonic demulsification and coalescing filter element for an oil filter. The main components of the device are a cotton sleeve, a fiber body, a metal plate, an oil inlet, and an ultrasonic transducer. When the device is in operation, an ultrasonic field is formed within the filter element. The high-frequency oscillation of the ultrasonic wave causes the emulsified oil droplets to break apart, and the demulsified small droplets are then coalesced into larger droplets. However, the device has the disadvantage of requiring high precision control of the ultrasonic frequency and intensity, resulting in high acoustic energy dissipation and difficulty in heat dissipation. This results in increased energy consumption and a dramatic increase in the device's temperature, leading to high maintenance and operating costs.

[0012] Chinese invention CN201510613478.6 describes a cyclone separator for deliquification and deslagging of natural gas. The device consists of an overflow pipe, a tangential inlet, a cylinder, and a conical coalescer, with an internal conical coalescer attachment flexibly secured to the cylinder. While this device can remove solid particles and small droplets from the gas, its separation accuracy is limited. The cyclone separation process suffers from secondary particle entrainment, limiting its applicability and preventing high-precision applications.

[0013] In summary, in view of the problems existing in conventional process technologies, such as large equipment footprint, difficulty in demulsifying emulsified oil, blockage by particulate impurities, and uneven equipment flow and pressure, this field urgently needs to develop a separation device that can achieve synergistic separation of oil and solids in wastewater and has wide adaptability, strong processing capacity, and long operating cycle, so as to meet the social goals of environmental friendliness and resource conservation. Summary of the Invention

[0014] The present invention provides a cyclone-coupled coalescence oil-solid collaborative separation device and method. The cyclone-coupled coalescence oil-solid collaborative separation device provided by the present invention has cyclone separation, oil-water coalescence, and backwashing functions, enabling three-phase separation of oily and solid wastewater. The oil-water coalescence structure can be cleaned by a backwashing structure, enabling recycling of the oil-water coalescence structure, resulting in efficient separation and long-term use.

[0015] In order to achieve the above object, the present invention provides the following technical solutions:

[0016] The present invention provides an oil-solid cooperative separation device with cyclone coupling and coalescence, comprising a tank body, wherein the tank body is provided with a backwash structure, an oil-water coalescence structure arranged around the outer surface of the backwash structure, and a cyclone separation structure arranged around the outer surface of the oil-water coalescence structure; the tank body is provided with a feed port for admitting oily and solid-containing wastewater, the feed port being connected to a screw pump, and a volute flow channel communicating with the interior of the tank body being arranged around the outer periphery of the tank body with the feed port as a starting point;

[0017] The cyclone separation structure includes a water-oil separation unit and a three-phase separation unit arranged in sequence from top to bottom. The water-oil separation unit is provided with a plurality of openings communicating with the interior of the tank body. The three-phase separation unit and the lower portion of the oil-water coalescing structure form a first overflow channel. The water-oil separation unit and the inner wall of the tank body form a second overflow channel communicating with the first overflow channel. The three-phase separation unit includes a spiral jacket extending downward from the volute flow channel as a starting point. A collection unit is provided below the three-phase separation unit.

[0018] The oil-water coalescing structure includes a fiber unit arranged around the periphery of the backwash structure, a hydraulic pressure collecting plate is provided above the fiber unit to help discharge the oil phase adsorbed in the fiber unit, the hydraulic pressure collecting plate is arranged around the periphery of the backwash structure, a head is provided above the hydraulic pressure collecting plate, and the head is connected to an oil outlet pipe that passes through the tank body.

[0019] The main body of the cyclone-coupled coalescence oil-solid collaborative separation device provided by the present invention is a tank structure, and a cyclone separation structure, an oil-water coalescence structure and a backwash structure are provided in the tank structure. Among them, the oil-containing and solid-containing wastewater enters the volute flow channel from the feed port and then enters the spiral jacket in the cyclone separation structure inside the tank body. As a major structural advantage of the present invention, the volute flow channel can change the disordered distribution of suspended particles and non-dissolved oil substances in the oil-containing and solid-containing wastewater into an orderly forward radial distribution, regulate the motion trajectory of the oil and solid phases in the three-dimensional rotating turbulent field, and thereby enhance the directional migration and separation effect of suspended matter and non-dissolved oil substances. As another major structural advantage in this statement, the spiral jacket can prolong the residence time of the oil-containing and solid-containing wastewater in the cyclone separation structure, and enhance the turbulence level of the oil-containing and solid-containing wastewater, further enhancing the cyclone separation effect of solid-phase pollutants in the oil-containing and solid-containing wastewater.

[0020] Based on the above, after the cyclonic separation of oily and solid wastewater, the solid phase falls into the collection unit and is then discharged from the tank. The separated oil and water phases move upward from the first overflow channel to the second overflow channel, ultimately entering the oil-water coalescing structure through the openings in the water-oil separation unit. The fiber units in the oil-water coalescing structure adsorb the oil and water phases, significantly enhancing the demulsification, adhesion, coalescence, and migration processes of the oil phase, thereby significantly improving oil-water separation efficiency. Under the pressure of the collecting hydraulic plate, the separated oil phase is discharged upward to the oil head and then discharged from the tank through the oil outlet pipe.

[0021] As the oil- and solid-containing wastewater continues to separate, the fiber unit reaches saturation with adsorbed particulate matter, causing a sudden increase in pressure drop. At this point, a backwash mechanism is required to clean the fiber unit to maintain the long-term operation of the device. Therefore, the oil-solid collaborative separation device provided by the present invention can effectively reduce the frequency of blockages during long-term operation, ensuring the long-term stable operation of the device.

[0022] In summary, the present invention provides a separation device that can simultaneously separate the water phase, oil phase and solid phase in oily and solid wastewater. The device uses the volute flow channel to perform preliminary phase sorting and then performs strong separation in the spiral jacket, thereby improving the operating efficiency of the entire device, and the addition of a backwash structure can reduce the maintenance cost of the fiber unit.

[0023] Preferably, the openings are arranged in a circular array on the water-oil separation unit.

[0024] Preferably, the ratio of the heights of the water-oil separation unit, the three-phase separation unit and the collection unit is 2:1:(1-2).

[0025] Preferably, the diameter of the first overflow channel is smaller than the diameter of the second overflow channel.

[0026] By utilizing the diameter difference between the first overflow channel and the second overflow channel, the positional design relationship between the first overflow channel and the second overflow channel, and the relationship between the cross-sectional flow velocity and height in fluid mechanics, low-speed coalescence after high-speed separation is achieved. Specifically, the water phase and the oil phase separated from the three-phase separation unit move upward along the first overflow channel with a smaller diameter under the action of high-speed swirling flow and enter the second overflow channel with a larger diameter, and complete the coalescence of the oil phase and the water phase with the oil-water coalescence structure in the second overflow channel; wherein, the second overflow channel has a larger diameter, which can provide more space for the coalescence of the oil phase and the water phase, and provide a smooth transition buffer zone for the water phase and the oil phase rushing out of the first overflow channel at high speed, so that the coalescence process is completed at a reasonable flow rate, helping the oil phase and the water phase to fully coalesce.

[0027] Preferably, the width of the tangential inlet of the volute flow channel is 1 to 2 times the width of the feed port, and the height of the tangential inlet of the volute flow channel is 1 to 3 times the height of the feed port.

[0028] Further preferably, the volute flow channel is an involute configuration structure, the volute angle is 270°, and the eccentricity is 6 to 10 cm.

[0029] Preferably, a cyclone separation channel for separating the water phase, solid phase and oil phase is formed between the spiral jacket and the inner wall of the tank body, and the cyclone separation channel connects the three-phase separation unit and the collection unit, and the collection unit includes a collection cavity and a sewage outlet located below the collection cavity.

[0030] Preferably, the structure of the water-oil separation unit is a cylinder, and the inner wall of the cylinder is derusted and coated with an oil-resistant anti-corrosion coating.

[0031] Preferably, a plurality of rotating blades are evenly arranged on the spiral jacket along the circumferential direction.

[0032] Further preferably, the spiral jacket is provided with 3 to 4 rotating blades along the circumferential direction, the width of the rotating blades is 9 to 14 cm, and the thickness of the rotating blades is 2 to 8 mm.

[0033] Further preferably, the spiral jacket is integrally formed using polytetrafluoroethylene as the material through 3D printing.

[0034] Further preferably, the linear shape of the rotating blade is a cylindrical helix, the pitch range is 100 to 300 mm, and the angle of the cylindrical helix in the horizontal direction is 22 to 42°.

[0035] The oil and solid phases flow in a spatial spiral along the rotating blades of the spiral jacket, creating a more intense rotational motion within the cyclone. Compared to conventional cyclones, the spiral jacket with rotating blades generates stronger centrifugal force, which facilitates the migration of solid particles to the outer wall of the spiral jacket, while the water and oil phases migrate to the inner wall of the spiral jacket, thereby improving separation efficiency. Furthermore, the spiral jacket increases the turbulence of the fluid (oil and solid wastewater), and turbulent mixing promotes collision and coalescence between oil droplets, further improving the device's separation efficiency for oil and solid wastewater.

[0036] Preferably, the fiber unit is composed of multiple fiber aggregation layers stacked in sequence, and the fiber aggregation layers are woven together by interlacing hydrophilic and oleophobic modified fibers and oleophilic and hydrophobic modified fibers. The stacking thickness of the fiber unit is 600 to 900 mm, and the fiber unit occupies 70 to 90% of the total internal volume of the cyclone separation structure.

[0037] Preferably, the fibers in the fiber unit are selected from at least one of metal fibers, glass fibers, polyester fibers, and polypropylene fibers, and the density of the fibers is 0.7 to 0.9.

[0038] Further preferably, the fiber aggregation layer is formed by interlacing hydrophilic-oleophobic modified fibers and oleophilic-hydrophobic modified fibers in an X or Ω weaving manner.

[0039] This fiber agglomeration layer has the dual functions of agglomerating oil droplets and filtering suspended solids. The fibers used are characterized by a large specific surface area, corrosion resistance, stable mechanical properties, and long service life. The aforementioned X-weave method can be understood as directly weaving the fiber bundle without changing its curvature, while the Ω-weave method can be understood as maintaining a certain curvature of the fiber bundle after weaving. Alternatively, other weaving methods can be used, as long as they ensure efficient adsorption between the fiber agglomeration layer and the oily and solid-containing wastewater. The weaving method provided by the inventors is a preferred reference, but the fiber agglomeration layer in the present invention can also be used with other weaving methods to achieve the desired effects of the present invention.

[0040] Preferably, the hydraulic collecting plate is provided with a plurality of groups of oil guide holes, the aperture of each group of oil guide holes increases outward from the center of the hydraulic collecting plate as the origin, the sum of the opening areas of the oil guide holes accounts for 40-50% of the surface area of ​​the hydraulic collecting plate, and the thickness of the hydraulic collecting plate is 6-8 cm; an oil collecting chamber connected to the oil outlet pipe is provided in the head.

[0041] Further preferably, the structure of the oil collecting chamber is a tapered structure.

[0042] Further preferably, the diameter of the oil guide hole is 4-7 mm.

[0043] Further preferably, the oil collecting plate is composed of a plurality of pressure plates with corresponding oil guide holes.

[0044] Further preferably, the number of the pressing plates is 3 to 4, and the thickness of each pressing plate is 2 cm.

[0045] Preferably, the backwash structure includes a backwash pipe that passes through the top of the tank body and extends into the three-phase separation unit. The backwash pipe is provided with an air inlet at one end located at the top of the tank body. The backwash pipe is also provided with a water inlet pipe arranged perpendicular to the backwash pipe and a water outlet pipe arranged opposite to the water inlet pipe.

[0046] Preferably, the feed port, sewage outlet, water inlet pipe and air inlet are all provided with an electromagnetic flow meter and a pressure tester.

[0047] Preferably, the oil outlet pipe is connected to a liquid level sensor and a temperature sensor.

[0048] Preferably, the water outlet pipe is connected to the regulating control box, and a water guide pipe is provided in the regulating control box.

[0049] The present invention also provides a method for oil-solid collaborative separation by cyclone-coupled coalescence, which uses the above-mentioned oil-solid collaborative separation device by cyclone-coupled coalescence to perform separation; the method comprises:

[0050] (1) The wastewater containing oil and solids enters the volute flow channel from the feed port. Under the action of the centrifugal field, the water phase, solid phase and oil phase in the wastewater containing oil and solids are sorted by using the weight and density differences of the water phase, solid phase and oil phase. The sorting result is: according to the direction of the volute flow channel from the side close to the tank body to the side away from the tank body, the solid phase, water phase and oil phase are sorted in order;

[0051] (2) The sorted wastewater containing oil and solids enters the three-phase separation unit inside the tank along the volute flow channel, and the spiral jacket in the three-phase separation unit is used to enhance the separation of the water phase, solid phase, and oil phase, so that the water phase and oil phase enter the water-oil separation unit, and the solid phase enters the collection unit and is discharged from the tank;

[0052] (3) The water phase and oil phase that enter the water-oil separation unit enter the fiber unit through the opening, and the small oil droplets in the oil phase undergo wetting, coalescence, collision, and aggregation in the fiber unit to form large oil droplets. Subsequently, the oil phase on the upper portion of the fiber unit is discharged under the action of the collecting plate, and the oil phase enters the head and is discharged from the oil outlet pipe outside the tank body, while the water phase sinks to the bottom of the fiber unit;

[0053] (4) When the escaping particles adsorbed in the fiber unit reach a saturated state, the fiber unit is backwashed using the backwash structure. After the backwash is completed, the water phase enters the collection unit and is discharged from the tank body;

[0054] (5) Repeat steps (1) to (4) to achieve continuous separation of oil-containing and solid-containing wastewater.

[0055] Small oil droplets wet and coalesce within the fiber unit, collide and coalesce into larger droplets. During this process, small oil droplets coalesce with each other or adhere to the fiber, causing demulsification, coalescence, and migration.

[0056] Preferably, in step (4), the backwashing time is 20 to 35 minutes.

[0057] Preferably, in step (5), the removal rate of suspended solids in the oily and solid-containing wastewater is ≥75%, and the removal rate of oil in the oily and solid-containing wastewater is ≥90%.

[0058] Preferably, during the separation process, the pressure drop inside the oil-solid collaborative separation device with cyclone coupling and coalescence is no more than 0.8 MPa.

[0059] Therefore, the present invention has the following beneficial effects:

[0060] (1) The cyclone-coupled coalescence oil-solid collaborative separation device provided by the present invention can simultaneously achieve three-phase separation of oil-containing and solid-containing wastewater, and has little impact on the separation efficiency during long-term use, thereby achieving long-term application.

[0061] (2) The present invention utilizes a volute flow channel to achieve a preliminary orderly arrangement of oil-containing and solid-containing wastewater, and adds a spiral jacket to enable the water phase, oil phase and solid phase after the preliminary orderly arrangement to undergo a strong rotational motion in a spatial spiral flow state, thereby quickly and effectively separating the water phase, oil phase and solid phase. At the same time, the strong rotational motion can help small oil droplets coalesce into large oil droplets, facilitating the subsequent recovery of the oil phase.

[0062] (3) The present invention combines the cyclone separation structure and the oil-water coalescence structure to achieve the coordinated separation of the oil phase and the solid phase in the oil- and solid-containing wastewater; on the one hand, the cyclone separation structure can effectively remove the solid suspended matter in the wastewater and coalesce some oil droplets. Compared with the case of using the oil-water coalescence structure alone, the addition of the cyclone separation structure can effectively solve the problem of solid suspended matter blockage and slow down the formation of the fiber bed filter cake in the oil-water coalescence structure, thereby improving the anti-fouling and clogging performance of the fiber unit; on the other hand, the oil-water coalescence structure can help remove the solid suspended matter particles and the oil phase that overflow and escape from the cyclone separation structure, and quickly coalesce the oil droplets. Compared with the case of using the cyclone separation structure alone, the oil-water coalescence structure can further intercept and process the overflowing solid suspended matter, thereby improving the purity of the separated oil phase.

[0063] (4) The present invention utilizes the diameter difference between the first overflow channel and the second overflow channel, the positional design relationship between the first overflow channel and the second overflow channel, and the relationship between cross-sectional flow velocity and height in fluid mechanics to achieve low-speed coalescence after high-speed separation. This design ensures that the accuracy and reliability of oil-water separation are maintained while improving separation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a front view of the oil-solid cooperative separation device with cyclone-coupled coalescence;

[0065] Figure 2 It is a structural schematic diagram of the oil-solid cooperative separation device with cyclone-coupled coalescence;

[0066] Figure 3 Schematic diagram of the internal structure of the oil-solid cooperative separation device with cyclone-coupled coalescence;

[0067] Figure 4 It is a cross-sectional schematic diagram of an oil-solid cooperative separation device with cyclone-coupled coalescence;

[0068] Figure 5 It is a top view of the hydraulic plate;

[0069] Figure 6 Schematic diagram of the X-weaving method of the fiber aggregation layer;

[0070] Figure 7 Schematic diagram of the Ω weaving method of the fiber aggregation layer;

[0071] Figure 8 It is a schematic diagram of the sorting in the volute flow channel;

[0072] Figure 9 Schematic diagram of the flow directions of the water phase, oil phase and solid phase in the oil-solid cooperative separation device with cyclone coupling and coalescence;

[0073] Figure 10 Schematic diagram of the backwash process in the oil-solid cooperative separation device with cyclone coupling and coalescence;

[0074] Figure 11 This is a comparison chart of suspended solids content at the import and export;

[0075] Figure 12 This is a comparison chart of import and export oil content;

[0076] Figure 13 is the curve of the oil residual rate in the fiber unit changing with the backwash time;

[0077] The numbers in the figure are: tank body 100, feed port 110, screw pump 120, volute flow channel 130, cyclone separation structure 200, water-oil separation unit 210, opening 211, three-phase separation unit 220, spiral jacket 221, rotating blades 221a, cyclone separation channel 222, collection unit 310, collecting chamber 311, sewage outlet 312, first overflow channel 320, second overflow channel 330, collecting oil plate 340, oil guide hole 341, head 350, oil collecting chamber 351, oil outlet pipe 360, oil-water coalescing structure 400, fiber unit 410, backwash structure 500, backwash pipe 510, air inlet 520, water inlet pipe 530, water outlet pipe 540. DETAILED DESCRIPTION

[0078] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below generally represent only a portion of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0079] Example 1

[0080] observe Figures 1 to 5It can be seen that this embodiment provides an oil-solid collaborative separation device with cyclone coupling and coalescence, including a tank body 100, in which a backwash structure 500, an oil-water coalescence structure 400 arranged on the outer surface of the backwash structure 500, and a cyclone separation structure 200 arranged on the outer surface of the oil-water coalescence structure 400 are arranged. The tank body 100 is provided with a feed port 110 for introducing oily and solid wastewater, the feed port 110 is connected to a screw pump 120, and a volute flow channel 130 is arranged around the outer periphery of the tank body 100 with the feed port 110 as the starting point and connected to the interior of the tank body 100. In addition, Figure 2 The tangential inlet width of the volute flow channel 130 is twice the width of the feed port 110, and the height of the tangential inlet of the volute flow channel 130 is twice the height of the feed port 110. The volute flow channel 130 is an involute configuration structure, with a volute angle of 270° and an eccentricity of 8 cm.

[0081] observe Figure 3 As can be seen, the cyclone separation structure 200 comprises, from top to bottom, a water-oil separation unit 210 and a three-phase separation unit 220. The water-oil separation unit 210 is a cylindrical structure, the inner wall of which has been derusted and coated with an oil-resistant corrosion-resistant coating. The diameter of the cylinder is 80% of the inner diameter of the tank 100, and the wall thickness is 2 mm. The cylinder is provided with a plurality of openings 211 communicating with the interior of the tank 100. The openings 211 are arranged in a circular array in the center of the cylinder.

[0082] observe Figure 4 As can be seen, the three-phase separation unit 220 and the lower portion of the oil-water coalescing structure 400 form a first overflow channel 320. The oil-water separation unit 210 and the inner wall of the tank body 100 form a second overflow channel 330 that communicates with the first overflow channel 320. The diameter of the first overflow channel 320 is smaller than the diameter of the second overflow channel 330. The three-phase separation unit 220 includes a spiral jacket 221 extending downward from the volute flow channel 130. The spiral jacket 221 is integrally formed using 3D printing and is made of polytetrafluoroethylene. Figure 3 In the figure, three rotating blades 221a are evenly arranged on the spiral jacket 221 along the circumference. The width of the rotating blade 221a used is 10 cm and the thickness is 3 mm. The linear shape of the rotating blade 221a is a cylindrical spiral line with a pitch range of 150 mm and an angle of the cylindrical spiral line in the horizontal direction of 24°.

[0083] Figure 4In the embodiment, a cyclone separation channel 222 for separating the water phase, solid phase and oil phase is formed between the spiral jacket 221 and the inner wall of the tank body 100. The cyclone separation channel 222 connects the three-phase separation unit 220 and the collection unit 310. A collection unit 310 is provided below the three-phase separation unit 220. The collection unit 310 includes a collection cavity 311 and a sewage outlet 312 located below the collection cavity 311. The height ratio of the water-oil separation unit 210, the three-phase separation unit 220 and the collection unit 310 is 2:1:2. The collection unit 310 is a conical cylinder, which facilitates the rapid discharge of the collected solid particles from the sewage outlet 312 out of the tank body 100.

[0084] The oil-water coalescing structure 400 includes a fiber unit 410 arranged around the periphery of the backwash structure 500. The fiber unit 410 is composed of a plurality of fiber coalescing layers stacked in sequence, and the fiber coalescing layers are woven by interlacing hydrophilic and oleophobic modified polyester fibers and oleophilic and hydrophobic modified polyester fibers (the weaving method can be selected). Figure 6 X braid as shown or Figure 7 The density of the polyester fiber used is 0.7, the stacking thickness of the fiber unit 410 is 800 mm, and the fiber unit 410 occupies 80% of the total internal volume of the cyclone separation structure 200.

[0085] Above the fiber unit 410, a hydraulic pressure collecting plate 340 is installed to facilitate the discharge of adsorbed oil from the fiber unit 410. This plate 340 is located around the periphery of the backwash structure 500. A sealing head 350 is located above the plate 340, within which is an oil collecting chamber 351 connected to the oil outlet pipe 360. The plate 340 consists of three plates, each 2 cm thick. Six groups of equally spaced oil guide holes 341 are arranged on the plate 340. The diameter of each group of oil guide holes 341 increases outward from the center of the plate 340 (the diameters of the oil guide holes 341 increase from the inside outward, in descending order, to 4 mm, 5 mm, 6 mm, and 7 mm). The combined area of ​​the openings 211 of the oil guide holes 341 accounts for 48% of the surface area of ​​the plate 340. When each hydraulic pressure collecting plate 340 is stacked and discharged, each hydraulic pressure collecting plate 340 is aligned with the center position and then stacked and discharged. At this time, it can be ensured that the positions of each oil guide hole 341 equally distributed on the hydraulic pressure collecting plate 340 are also aligned, which can help the oil phase to be discharged from the hydraulic pressure collecting plate 340 layer by layer in an orderly and rapid manner.

[0086] The backwash structure 500 includes a backwash pipe 510 that passes through the top of the tank body 100 and extends into the three-phase separation unit 220. The backwash pipe 510 is located at one end of the top of the tank body 100 and is provided with an air inlet 520. The backwash pipe 510 is also provided with a water inlet pipe 530 arranged vertically with the backwash pipe 510 and a water outlet pipe 540 arranged opposite to the water inlet pipe 530.

[0087] The main body of the cyclone-coupled coalescence oil-solid collaborative separation device provided by the present invention is a tank body 100 structure, in which a cyclone separation structure 200, an oil-water coalescence structure 400 and a backwash structure 500 are provided. Among them, the oil-containing and solid-containing wastewater enters the volute flow channel 130 from the feed port 110 and then enters the spiral jacket 221 in the cyclone separation structure 200 inside the tank body 100. As a major structural advantage of the present invention, the volute flow channel 130 can change the disordered distribution of suspended particles and non-dissolved oil substances in the oil-containing and solid-containing wastewater into an orderly radial distribution, regulate the motion trajectory of the oil-solid two-phase in the three-dimensional rotating turbulent field, and thus enhance the directional migration and separation effect of suspended matter and non-dissolved oil substances. As another major structural advantage in this statement, the spiral jacket 221 can prolong the residence time of the oil-containing and solid-containing wastewater in the cyclone separation structure 200, and enhance the turbulence level of the oil-containing and solid-containing wastewater, further enhancing the cyclone separation effect of solid-phase pollutants in the oil-containing and solid-containing wastewater.

[0088] On the basis of the above, after the cyclonic separation of the oily and solid wastewater, the solid phase falls into the collection chamber 311 in the collection unit 310 and is then discharged from the tank body 100 through the sewage outlet 312; the separated oil phase and water phase move upward from the first overflow channel 320 to the second overflow channel 330 and finally enter the oil-water coalescing structure 400 through the opening 211 provided in the oil-water separation unit 210. The fiber unit 410 in the oil-water coalescing structure 400 is used to adsorb the oil and water phases. The fiber unit 410 can significantly enhance the demulsification, adhesion, aggregation and migration processes of the oil phase, thereby greatly improving the oil-water separation efficiency. The separated oil phase is discharged upward to the head 350 under the pressure of the hydraulic plate 340 and then discharged from the tank body 100 through the oil outlet pipe 360. As the oily and solid-containing wastewater is continuously separated and agglomerated, the particulate matter adsorbed by the fiber unit 410 reaches saturation, causing a sudden increase in pressure drop. At this time, the fiber unit 410 needs to be cleaned using the backwash structure 500 to maintain the long-term use of the entire oil-solid collaborative separation device.

[0089] The oil-solid collaborative separation device provided in this embodiment can effectively reduce the frequency of blockage during long-term operation and ensure the long-term stable operation of the device.

[0090] Example 1: Method of using the separation device:

[0091] (1) Figure 8 As shown, the oily and solid-containing wastewater enters the volute channel through the feed port 110. Due to the density difference between the oil and solid phases, the oily and solid-containing wastewater migrates and sorts in the volute channel. The heavy phase solid particles migrate to the outer wall of the volute channel, and the light phase oil droplets migrate to the inner wall of the volute channel.

[0092] (2) After the sorting is completed, it continues to enter the three-phase separation unit 220 along the volute channel. Then, the rotating blades 221a of the spiral jacket 221 further enhance the cyclonic separation effect of the solid phase pollutants, and the solid particles are concentrated into the collection unit 310 by the self-rotation and revolution coupling, and then discharged out of the tank body 100 through the sewage outlet 312 at the bottom of the collection unit 310 (such as Figure 9 shown).

[0093] (3) After step (2) is completed, the separated light phase oil droplets move upward along the first overflow channel to the second overflow channel 330, and begin to interact and coalesce with the fiber unit 410 in the water-oil separation unit 210 through the opening 211 on the water-oil separation unit 210. Under the action of the flow field drag force, due to the tension difference between the surface of the hydrophilic and hydrophobic fibers, the dispersed phase oil droplets undergo wetting and collision coalescence in the porous medium channel where the fibers are stacked. In this process, the oil droplets coalesce with each other or adhere to the oleophilic fibers to cause demulsification, coalescence, and migration. Due to its light density, the oil phase floats up through the hydraulic plate 340 and flows into the oil collection chamber 351 inside the head 350. After the oil storage in the oil collection chamber 351 reaches a certain concentration, it is discharged from the oil outlet pipe 360.

[0094] (4) After the cyclone coalescence device has been running for a period of time, the escaped particles intercepted by the fiber unit 410 have reached saturation, causing the bed pressure drop to rise sharply. At this time, the device needs to be backwashed. Figure 10 In the illustrated path, purified water flows by gravity from the water inlet pipe 530 into the backwash pipe 510 and is discharged from the backwash pipe 510 through the outlet of the water outlet pipe 540. A water-gas mixture is introduced into the water inlet pipe 530 and the air inlet 520, respectively, at a water-to-nitrogen weight ratio of 1:3. The water-gas mixture then flows through the backwash pipe 510 into the fiber unit 410 for backwashing. Finally, the backwash liquid flows out of the second overflow channel 330 through the opening 211 in the water-oil separation unit 210 and is discharged from the tank 100 by gravity through the drain port 312 at the bottom of the collection unit 310.

[0095] (5) Repeat steps (1) to (4) to achieve continuous separation of oil-containing and solid-containing wastewater.

[0096] Application Example 1

[0097] The target wastewater treatment project was a petroleum refining company in Xinjiang, which produces oily and solid wastewater from its crude oil atmospheric and vacuum distillation, catalytic cracking, and hydrotreating processes. This wastewater contains petroleum-based substances such as alkanes, olefins, and aromatic hydrocarbons, as well as solid particles such as coal, catalyst powder, and sludge, as well as chemical pollutants such as organic matter, acids, and alkalinity.

[0098] The separation device given in Example 1 was used and the oily and solid-containing wastewater was separated and treated according to the above-mentioned usage method.

[0099] 1. The water quality conditions of the target wastewater to be treated in this section are shown in Table 1 below

[0100] Table 1 Water quality conditions

[0101]

[0102] 2. The working conditions in this section are shown in Table 2 below

[0103] Table 2 Working conditions

[0104]

[0105] 3. Implementation process

[0106] The target wastewater treatment is 2.5m 3 A flow rate of / h enters the oil-solid synergistic separation device with cyclone coupling and coalescence. The pressure range of the device is adjusted to 0.1-0.3MPa. When the pressure reaches a stable value, the readings of the magnetic flowmeter and pressure gauge at each inlet and outlet are read.

[0107] 4. Implementation effect analysis

[0108] The device was used to conduct a 21-day side-line experiment on the target wastewater. The inlet and outlet water samples were taken and the suspended solids content and oil content in the inlet and outlet water samples were measured. The results of the suspended solids content in the inlet and outlet water bodies are as follows: Figure 10 As shown in the figure, the oil concentration in the inlet and outlet water is measured as follows: Figure 11 shown.

[0109] The results show that this device has obvious treatment effects on suspended solids and oily substances in the target wastewater. From the measured suspended solids results, it can be seen that after the target wastewater is treated by this device, the inlet suspended solids content is concentrated from 400-500 mg / L to more than 1800 mg / L, and the suspended solids separation efficiency is more than 75%.

[0110] This device also has a good effect on the removal of oil substances. From the measured inlet and outlet oil content results, it can be seen that the inlet oil content is 450-500mg / L, and the outlet oil concentration of the water treated by this equipment is controlled below 50mg / L. The removal efficiency of emulsified oil and floating oil in water is more than 90%. This device maintains a high separation efficiency for the oil phase and suspended matter in wastewater over a long period of time. The results show that this device can operate stably over a long period of time.

[0111] When the pressure drop of the fiber unit reaches the set pressure (0.4Mpa), the fiber unit is backwashed and the backwash water flow rate is set to 2m 3 / h, set the backwash gas flow rate to 6m 3 / h. A water-gas mixture (water and nitrogen weight ratio of 1:3) enters the fiber unit from the backwash pipe to wash away suspended particles and residual oil. After the backwash is completed, a portion of the fiber unit surface is cut and dried. The residual rate is calculated by measuring the change in the mass of the fiber unit before and after drying, and a curve of the residual rate versus regeneration time is drawn, as shown in the figure. Figure 12 shown.

[0112] The results showed that the initial residual rate of suspended solids averaged 11.3%, and the initial residual rate of oil content averaged 16.9%. As the backwash time increased, the content of intercepted suspended solid particles and oil droplets gradually decreased. When the backwash time reached 35 minutes, the residual rate of suspended solids in the fiber unit decreased from 11.3% to 4.1%, and the residual rate of oil content in the fiber unit decreased from 16.9% to 6.07%. As the backwash time continued to increase, the residual rates of suspended solids and oil content in the fiber unit tended to stabilize, indicating that the backwash effect was stable and effective, and the optimal regeneration backwash time was 20 minutes. The backwash experiments showed that the fiber unit of this device has good regeneration properties.

Claims

1. An oil-solid synergistic separation device with cyclone coupling and coalescence, characterized in that: The invention comprises a tank body, wherein a backwash structure, an oil-water coalescing structure arranged on the outer surface of the backwash structure, and a cyclone separation structure arranged on the outer surface of the oil-water coalescing structure are provided in the tank body; a feed port for introducing oily and solid wastewater is provided on the tank body, the feed port is connected to a screw pump, and a volute flow channel communicating with the interior of the tank body is provided around the outer periphery of the tank body with the feed port as the starting point; The cyclone separation structure includes a water-oil separation unit and a three-phase separation unit arranged in sequence from top to bottom. The water-oil separation unit is provided with a plurality of openings communicating with the interior of the tank body. The three-phase separation unit and the lower portion of the oil-water coalescing structure form a first overflow channel. The water-oil separation unit and the inner wall of the tank body form a second overflow channel communicating with the first overflow channel. The three-phase separation unit includes a spiral jacket extending downward from the volute flow channel as a starting point. A collection unit is provided below the three-phase separation unit. The oil-water coalescing structure includes a fiber unit arranged around the periphery of the backwash structure, a hydraulic pressure collecting plate is provided above the fiber unit to help discharge the oil phase adsorbed in the fiber unit, the hydraulic pressure collecting plate is arranged around the periphery of the backwash structure, a head is provided above the hydraulic pressure collecting plate, and the head is connected to an oil outlet pipe that passes through the tank body.

2. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1, characterized in that: The height ratio of the water-oil separation unit, the three-phase separation unit and the collection unit is 2:1:(1-2); the diameter of the first overflow channel is smaller than the diameter of the second overflow channel.

3. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1, characterized in that: A cyclone separation channel for separating the water phase, solid phase and oil phase is formed between the spiral jacket and the inner wall of the tank body. The cyclone separation channel connects the three-phase separation unit and the collection unit. The collection unit includes a collection cavity and a sewage outlet located below the collection cavity.

4. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1 or 3, characterized in that: The spiral jacket is evenly provided with a plurality of rotating blades along the circumferential direction.

5. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1, characterized in that: The fiber unit is composed of multiple fiber aggregation layers stacked in sequence, and the fiber aggregation layers are woven by interlacing hydrophilic and oleophobic modified fibers and oleophilic and hydrophobic modified fibers. The stacking thickness of the fiber unit is 600 to 900 mm, and the fiber unit accounts for 70 to 90% of the total internal volume of the cyclone separation structure.

6. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1 or 5, characterized in that: The fibers in the fiber unit are selected from at least one of metal fibers, glass fibers, polyester fibers, and polypropylene fibers, and the density of the fibers is 0.7 to 0.

9.

7. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1, characterized in that: The hydraulic pressure collecting plate is provided with a plurality of groups of oil guide holes, and the aperture of each group of oil guide holes increases outward from the center of the hydraulic pressure collecting plate. The sum of the opening areas of the oil guide holes accounts for 40-50% of the surface area of ​​the hydraulic pressure collecting plate. The thickness of the hydraulic pressure collecting plate is 6-8 cm; an oil collecting cavity connected to the oil outlet pipe is provided in the head.

8. The oil-solid synergistic separation device of cyclone-coupled coalescence according to claim 1, characterized in that: The backwash structure includes a backwash pipe that passes through the top of the tank body and extends into the three-phase separation unit. The backwash pipe is provided with an air inlet at one end located at the top of the tank body. The backwash pipe is also provided with a water inlet pipe arranged perpendicular to the backwash pipe and a water outlet pipe arranged opposite to the water inlet pipe.

9. A method for oil-solid synergistic separation by cyclone-coupled coalescence, characterized in that: Separation is performed using the oil-solid collaborative separation device of cyclone-coupled coalescence as claimed in any one of claims 1 to 8; comprising: (1) The wastewater containing oil and solids enters the volute flow channel from the feed port. Under the action of the centrifugal field, the water phase, solid phase and oil phase in the wastewater containing oil and solids are sorted by using the weight and density differences of the water phase, solid phase and oil phase. The sorting result is: according to the direction of the volute flow channel from the side close to the tank body to the side away from the tank body, the solid phase, water phase and oil phase are sorted in order; (2) The sorted wastewater containing oil and solids enters the three-phase separation unit inside the tank along the volute flow channel, and the spiral jacket in the three-phase separation unit is used to enhance the separation of the water phase, solid phase, and oil phase, so that the water phase and oil phase enter the water-oil separation unit, and the solid phase enters the collection unit and is discharged from the tank; (3) The water phase and oil phase that enter the water-oil separation unit enter the fiber unit through the opening, and the small oil droplets in the oil phase undergo wetting, coalescence, collision, and aggregation in the fiber unit to form large oil droplets. Subsequently, the oil phase on the upper portion of the fiber unit is discharged under the action of the collecting plate, and the oil phase enters the head and is discharged from the oil outlet pipe outside the tank body, while the water phase sinks to the bottom of the fiber unit; (4) When the escaping particles adsorbed in the fiber unit reach a saturated state, the fiber unit is backwashed using the backwash structure. After the backwash is completed, the water phase enters the collection unit and is discharged from the tank body; (5) Repeat steps (1) to (4) to achieve continuous separation of oil-containing and solid-containing wastewater.

10. The method for oil-solid synergistic separation by cyclone-coupled coalescence according to claim 9, characterized in that: In step (4), the backwashing time is 20 to 35 minutes; In step (5), after continuous separation, the removal rate of suspended solids in the oily and solid-containing wastewater is ≥75%, and the removal rate of oil in the oily and solid-containing wastewater is ≥90%.

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