Rotational flow coupling coalescence oil-solid synergistic separation device and method

Abstract

The invention relates to the technical field of petrochemical wastewater separation and purification, in particular to a rotational flow coupling coalescence oil-solid synergistic separation device and method. The invention provides a rotational flow coupling coalescence oil-solid synergistic separation device. The rotational flow coupling coalescence oil-solid synergistic separation device is provided with a rotational flow separation structure, an oil-water coalescence structure and a backwashing structure. According to the cyclone separator, the particles are distributed in the radial direction along the rotating direction through the volute flow channel, and the retention time of fluid is optimized through a spiral jacket structure in the cyclone separation structure, so that the cyclone separation effect of solid-phase pollutants is enhanced. In an oil-water coalescence structure, demulsification, adhesion, coalescence and migration of emulsified oil drops are enhanced through a fiber unit with oleophobic and oleophobic properties. The device has the advantages of stable anti-pollution and anti-blocking performance, high oil-solid separation efficiency, low maintenance cost and small occupied area in long-period operation.

Description

Technical Field

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

[0002] At present, the petrochemical production industry produces a large amount of oily and solid-containing wastewater during the atmospheric pressure reduction and catalytic process. The recycling and treatment of such wastewater is an important part of environmental protection development. The direct discharge of oily and solid-containing wastewater without treatment not only causes serious environmental pollution, but also causes a large amount of oil resources to be wasted. The source of oily wastewater is very wide and the components are complex. According to the particle size range of oil, the oil exists in the form of dissolved, free and emulsified. Its suspended matter often carries impurities such as surfactants, bacteria, and sulfides, which increases the difficulty of wastewater treatment. According to the characteristics of large treatment volume, many particles, and small particle size of dispersed oil droplets of this type of wastewater, the commonly used treatment methods are gravity sedimentation, cyclone centrifugation, electrolysis, salting out, membrane separation, flotation, etc. However, it is difficult to achieve the purification requirements by using a single separation method. With the increasing improvement of national environmental protection planning and guidance, domestic and foreign researchers have made many efforts to develop new devices and processes for coupling various separation technologies.

[0003] Compared with chemical methods, the coalescence method is an efficient, energy-free, pollution-free coarse-graining technology, which has outstanding advantages in the treatment of oily wastewater. The common material in the coalescence method is fiber, and the fibers with different hydrophilic and hydrophobic properties are woven into fiber units in an X or Ω manner. The fiber unit has the characteristics of huge specific surface area and complex pore channels. The oil droplets collide, intercept, adsorb, and wet under the action of various forces, which can achieve oil-water separation to a great extent.

[0004] Chinese utility model CN202221224701.X provides a cyclone flotation coalescence oil remover, including an oil remover, a water inlet pipe and an oil removal pipe, and 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 driving 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, the cylinder body is provided with a hydraulic cyclone 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 chambers of the equipment have the problem of uneven flow or pressure, 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 baffle, a separation tube, an oil guide tube and a support plate, etc. The device processes wastewater from top to bottom and has good operating stability. It 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 fibers is cleaned manually, which increases the cost.

[0007] Chinese utility model CN201720630642.9 provides a cyclone coalescence oil-water separation device, the main body of the device includes a cyclone tank and a partition plate, the partition plate divides the inner cavity of the cyclone tank into a liquid inlet cavity and a liquid separation cavity, an overflow oil outlet is set at the top of the tank, and a water outlet is set at the bottom of the tank. By generating a strong cyclone in the cyclone cavity and utilizing the density difference between the dispersed phase and the continuous phase, the purpose of two-phase separation is achieved. However, there is a problem of secondary entrainment of particles in the separation process, and oil-solid synergistic separation cannot be achieved, which is not suitable for high-precision applications.

[0008] Chinese invention CN202110147232.X provides a multi-stage cyclone coalescence circulating hydrogen dehydrogenator, including a tank body, a tank 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 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 gradient graded dehydrogenation treatment 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 provides an oil-water separation device, the main part of which consists of four chambers, cyclone separators are arranged in the first two chambers, polypropylene fillers are arranged on the upper part of the last two chambers, stainless steel corrugated fillers are arranged on the lower part, and a gas generator is arranged at the bottom of the agglomeration zone. The oil-containing liquid is mixed through a tubular reactor and then enters the four chambers in turn for four separation operations. Although the device has a certain separation effect, it is large in size, the second and third chambers are prone to clogging, and a certain amount of surfactant needs to be added, which increases additional costs.

[0010] Patent application CN201820174928.5 discloses a new type of hydrocyclone coalescence oil remover device, which consists of a tank body and a filter. The tank body is equipped with a cyclone chamber and a filler chamber. The cyclone is connected to the sewage outlet inlet, the cyclone sewage outlet is connected to the filler chamber, and a floating oil collector is added on the top of the tank body. The device uses a PLC control system. The disadvantage is that its structure is complex, and many accessories inside the tank body are not conducive to repair and maintenance. Its backwashing uses high-temperature steam, which is easy to cause aging and damage to the pipeline.

[0011] Chinese invention CN201810712352.8 discloses an ultrasonic demulsification and coalescence filter element device for an oil filter. The main parts of the device are a cotton sleeve, a fiber body, a metal plate, an oil inlet, and an ultrasonic transducer. When the device is working, an ultrasonic field is formed inside the filter element. The emulsified oil causes droplets to break under the high-frequency oscillation of the ultrasonic wave, and then the demulsified small droplets are coalesced into large droplets. The disadvantage of this device is that it has high requirements for the control accuracy of the frequency and intensity of the ultrasonic wave, the dissipation of the acoustic energy is large, and the heat dissipation is difficult, which causes an increase in energy consumption costs and a sharp rise in the temperature of the equipment, and high equipment maintenance and operating costs.

[0012] Chinese invention CN201510613478.6 provides a cyclone separator for deliquification and slag removal of natural gas. The device is composed of an overflow pipe, a tangential inlet, a cylinder, and a conical coalescer from top to bottom, and the internal conical coalescing attachment is flexibly fixed to the cylinder. The device can remove solid particles and small droplets in the gas, but the separation accuracy is not high. There is a problem of secondary entrainment of particles in the cyclone separation process, and the scope of application is limited, and it cannot be used in 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 pressure, there is an urgent need in this field to develop a separation device that can achieve synergistic separation of oil and solid 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, can realize three-phase separation of oil-containing and solid-containing wastewater, and the oil-water coalescence structure can be cleaned by the backwashing structure to realize the recycling of the oil-water coalescence structure, and has the characteristics of high-efficiency 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 of cyclone coupling coalescence, comprising a tank body, wherein a backwash structure, an oil-water coalescence structure arranged on the outer surface of the backwash structure, and a cyclone separation structure arranged on the outer surface of the oil-water coalescence structure are arranged in the tank body; a feed port for introducing oil-containing and solid-containing wastewater is arranged on the tank body, a screw pump is connected to the feed port, and a volute flow channel communicating with the inside of the tank body is arranged around the outer periphery of the tank body with the feed port as the starting point;

[0017] The cyclone separation structure comprises 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 part 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 comprises a spiral jacket extending downward from the volute flow channel as a starting point, and a collecting 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 liquid collecting plate is arranged above the fiber unit to help discharge the oil phase adsorbed in the fiber unit, the liquid collecting plate is arranged around the periphery of the backwash structure, a head is arranged above the liquid 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 cooperative 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 arranged inside 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 movement trajectory of the oil-solid two-phase in the three-dimensional rotating turbulent field, and then 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 degree 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] On the basis of the above, after the cyclone separation, the solid phase of the oil-containing and solid-containing wastewater falls into the collection unit and is then discharged from the tank; the separated oil phase and water phase move upward from the first overflow channel to the second overflow channel and finally enter the oil-water coalescence structure through the openings on the water-oil separation unit. The fiber unit in the oil-water coalescence structure is used to adsorb the oil phase and the water phase. The fiber unit can significantly enhance the demulsification, adhesion, aggregation and migration process of the oil phase, thereby greatly improving the oil-water separation efficiency. The separated oil phase is discharged upward to the head under the pressure of the collecting hydraulic plate and then discharged from the tank body through the oil outlet pipe.

[0021] As the oil- and solid-containing wastewater is continuously separated, the particles adsorbed by the fiber unit reach saturation, causing a sudden increase in pressure drop. At this time, the fiber unit needs to be cleaned using a backwash structure to maintain the long-term use of the device. Therefore, the oil-solid cooperative separation device provided by the present invention can effectively reduce the blockage frequency during long-term operation and ensure 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 oil-containing and solid-containing 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, a diameter of the first overflow channel is smaller than a diameter of the second overflow channel.

[0026] The low-speed coalescence after high-speed separation is achieved by utilizing the diameter difference between the first overflow channel and the second overflow channel, the position design relationship between the first overflow channel and the second overflow channel, and the relationship between the cross-sectional flow velocity and the height in fluid mechanics. 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 swirl 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 a high speed, so that the coalescence process is completed at a reasonable flow rate, which helps 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 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 coated with an oil-resistant anti-corrosion coating after rust removal.

[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 a material through 3D printing.

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

[0035] The oil and solid phases present a spatial spiral flow state along the rotating blades of the spiral jacket, causing the fluid to produce a stronger rotational motion in the cyclone. Compared with ordinary cyclones, the spiral jacket with rotating blades can generate stronger centrifugal force, making it easier for solid phase particles to migrate to the outer wall of the spiral jacket, and the water phase and oil phase to migrate to the inner wall of the spiral jacket, thereby improving the separation efficiency. Furthermore, the spiral jacket increases the turbulence of the fluid (wastewater containing oil and solids), and turbulent mixing is conducive to the collision and coalescence between oil droplets, further improving the separation efficiency of the device for wastewater containing oil and solids.

[0036] Preferably, the fiber unit is composed of a plurality of fiber aggregation layers stacked in sequence, the fiber aggregation layers are woven together by interlacing hydrophilic-oleophobic modified fibers and oleophilic-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 the hydrophilic-oleophobic modified fibers and the oleophilic-hydrophobic modified fibers in an X or Ω weaving manner.

[0039] The fiber agglomeration layer has the dual functions of agglomerating oil droplets and filtering suspended matter, and the fibers used have the characteristics of large specific surface area, corrosion resistance, stable mechanical properties, and long service life. The above-mentioned X weaving method can be understood as directly weaving without changing the curvature of the fiber bundle, and the Ω weaving method can be understood as the fiber bundle maintaining a certain curvature after weaving. Or other weaving methods can be used, as long as efficient adsorption can occur between the fiber agglomeration layer and the oil-containing and solid-containing wastewater. Here, the weaving method provided by the inventor can be a preferred reference, but the use of the fiber agglomeration layer in the present invention can still be achieved by other weaving methods to achieve the desired effect of the present invention.

[0040] Preferably, the hydraulic pressure collecting plate is provided with a plurality of groups of oil guide holes, the aperture of each group of oil guide holes increases outwards with the center of the hydraulic pressure 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 pressure collecting plate, and 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 sealing 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 platen 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 vertically arranged with the backwash pipe and a water outlet pipe 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, a liquid level sensor and a temperature sensor are connected to the oil outlet pipe.

[0048] Preferably, the water outlet pipe is connected to a 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 coupling coalescence, which uses the above-mentioned oil-solid collaborative separation device by cyclone coupling coalescence for separation; comprising:

[0050] (1) The wastewater containing oil and solid 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 solid 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 in order;

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

[0052] (3) The water phase and the oil phase that enter the water-oil separation unit enter the fiber unit through the openings, and the small oil droplets in the oil phase undergo wetting and agglomeration and collision and coalescence in the fiber unit to form large oil droplets, and then the oil phase on the upper part 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 tank body through the oil outlet pipe, and 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 a backwashing structure. After the backwashing 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- and solid-containing wastewater.

[0055] Among them, small oil droplets are wetted and coalesced in the fiber unit and collided to form large oil droplets. In this process, small oil droplets coalesce with each other or oil droplets adhere to the fiber to demulsify, coalesce and migrate.

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

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

[0058] Preferably, during the separation process, the pressure drop inside the oil-solid cooperative separation device of cyclone coupling coalescence is not higher 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 the long-term use has little impact on the separation efficiency, and can achieve 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 under 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 to coalesce into large oil droplets, facilitating the subsequent recovery of the oil phase.

[0062] (3) The present invention combines a cyclone separation structure and an oil-water coalescing 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 where the oil-water coalescing structure is used alone, the addition of the cyclone separation structure can effectively solve the problem of clogging by the solid suspended matter and slow down the formation of the fiber bed filter cake in the oil-water coalescing structure, thereby improving the anti-fouling and clogging performance of the fiber unit; on the other hand, the oil-water coalescing 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 where the cyclone separation structure is used alone, the oil-water coalescing 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 realizes low-speed coalescence after high-speed separation by means of the diameter difference between the first overflow channel and the second overflow channel, the position 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. This design can ensure the accuracy and reliability of oil-water separation while improving the separation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0066] Figure 3 It is a schematic diagram of the internal structure of the oil-solid cooperative separation device of 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 pressure collecting 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] Fig. 9 It is a schematic diagram of the flow directions of the water phase, oil phase and solid phase in the oil-solid cooperative separation device of cyclone coupling coalescence;

[0073] Fig.10 It is a schematic diagram of the backwash process in the oil-solid cooperative separation device of cyclone-coupled coalescence;

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

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

[0076] Fig.13 is the variation curve of oil residual rate in fiber unit with backwashing 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, collecting unit 310, collecting chamber 311, drain port 312, first overflow channel 320, second overflow channel 330, hydraulic pressure collecting 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 is further described below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0079] Example 1

[0080] observe Figures 1 to 5It can be seen that the present embodiment provides an oil-solid synergistic separation device with cyclone coupling and coalescence, comprising 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 oil-containing and solid-containing wastewater, the feed port 110 is connected to a screw pump 120, and a volute flow channel 130 connected to the inside of the tank body 100 is arranged around the outer periphery of the tank body 100 with the feed port 110 as the starting point. 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, the volute angle is 270°, and the eccentricity is 8 cm.

[0081] observe Figure 3 It can be seen that the cyclone separation structure 200 includes a water-oil separation unit 210 and a three-phase separation unit 220 arranged in sequence from top to bottom. The structure of the water-oil separation unit 210 is a cylinder, and the inner wall of the cylinder is coated with an oil-resistant anti-corrosion coating after rust removal. The diameter of the cylinder is 80% of the inner diameter of the tank body 100, and the wall thickness of the cylinder is 2 mm. The cylinder is provided with a plurality of openings 211 connected to the inside of the tank body 100, and the openings 211 are arranged in a circular array in the middle of the cylinder.

[0082] observe Figure 4 It can be seen that the three-phase separation unit 220 and the lower part of the oil-water coalescing structure 400 form a first overflow channel 320, and the water-oil separation unit 210 and the inner wall of the tank body 100 form a second overflow channel 330 connected to the first overflow channel 320, and 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 as a starting point, and the spiral jacket 221 is made of polytetrafluoroethylene and integrally formed by 3D printing. Figure 3 In the figure, three rotating blades 221a are evenly arranged on the spiral jacket 221 along the circumferential direction. The width of the rotating blade 221a used is 10cm and the thickness is 3mm. The linear shape of the rotating blade 221a is a cylindrical spiral line, the pitch range is 150mm, and the angle of the cylindrical spiral line in the horizontal direction is 24°.

[0083] Figure 4In the embodiment, a cyclone separation channel 222 for separating the water phase, the solid phase and the oil phase is formed between the spiral jacket 221 and the inner wall of the tank body 100, and 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, and 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. Among them, the collection unit 310 is a conical cylinder, which facilitates the collected solid particles to be quickly discharged from the sewage outlet 312 outside the tank body 100.

[0084] The oil-water coalescing structure 400 includes a fiber unit 410 arranged around the outer 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 interlaced and woven by hydrophilic and oleophobic modified polyester fibers and oleophilic and hydrophobic modified polyester fibers (the weaving method can be selected from 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] A hydraulic pressure collecting plate 340 is provided above the fiber unit 410 to help discharge the oil phase adsorbed in the fiber unit 410. The hydraulic pressure collecting plate 340 is arranged around the outer periphery of the backwash structure 500. A sealing head 350 is provided above the hydraulic pressure collecting plate 340. An oil collecting cavity 351 connected to the oil outlet pipe 360 ​​is provided in the sealing head 350. There are three hydraulic pressure collecting plates 340, each of which is 2 cm thick. Six groups of oil guide holes 341 are arranged in equal parts on the hydraulic pressure collecting plate 340. The diameter of each group of oil guide holes 341 increases outwards from the center of the hydraulic pressure collecting plate 340 as the origin (the diameter of the oil guide holes 341 is 4 mm, 5 mm, 6 mm, and 7 mm from the inside to the outside). The sum of the areas of the openings 211 of the oil guide holes 341 accounts for 48% of the upper surface area of ​​the hydraulic pressure collecting 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 arranged 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 vertically arranged with the backwash pipe 510 and a water outlet pipe 540 opposite to the water inlet pipe 530.

[0087] The main body of the oil-solid synergistic separation device of cyclone coupling and coalescence provided by the present invention is a tank body 100 structure, and a cyclone separation structure 200, an oil-water coalescence structure 400 and a backwash structure 500 are arranged in the tank body 100 structure. 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 movement trajectory of the oil-solid two-phase in the three-dimensional rotating turbulent field, and then 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 degree 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 cyclone separation, the solid phase of the oil-containing and solid-containing wastewater falls into the collecting cavity 311 in the collection unit 310 and is then discharged from the tank body 100 through the sewage outlet 312; and 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 opened on the water-oil separation unit 210, and the fiber unit 410 in the oil-water coalescing structure 400 is used to adsorb the oil phase and the water phase. The fiber unit 410 can significantly enhance the demulsification, adhesion, aggregation and migration process 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 pressure collecting plate 340 and then discharged from the tank body 100 through the oil outlet pipe 360. With the continuous separation and aggregation of oil- and solid-containing wastewater, 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 cooperative separation device provided in this embodiment can effectively reduce the blockage frequency 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 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, the solid particles continue to enter the three-phase separation unit 220 along the volute passage. 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 in the collection unit 310 by the self-rotation and revolution coupling, and then discharged from the tank body 100 through the sewage outlet 312 at the bottom of the collection unit 310 (such as Fig. 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 flow field drag, due to the tension difference between the hydrophilic and hydrophobic fiber surfaces, 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 undergo demulsification, coalescence, and migration. Due to its light density, the oil phase floats up through the hydraulic pressure collecting plate 340 and flows into the oil collecting chamber 351 inside the head 350. After the oil storage in the oil collecting chamber 351 is enriched to 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. Fig.10 In the path shown, the purified water enters the backwash pipe 510 from the water inlet pipe 530 by gravity, and is discharged from the backwash pipe 510 through the outlet of the water outlet pipe 540. The water-gas mixture is respectively introduced into the water inlet pipe 530 and the air inlet 520 according to the weight ratio of water to nitrogen of 1:3, and the water-gas mixture enters the fiber unit 410 through the backwash pipe 510 for backwashing, and finally the backwash liquid flows out of the second overflow channel 330 through the opening 211 on the water-oil separation unit 210, and is discharged from the tank body 100 from the sewage outlet 312 at the bottom of the collection unit 310 by gravity.

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

[0096] Application Example 1

[0097] The oily and solid wastewater produced by a petroleum refining enterprise in Xinjiang during the process of crude oil atmospheric and vacuum distillation, catalytic cracking, and hydrofining was used as the target wastewater for treatment. This type of wastewater contains petroleum substances such as alkanes, olefins, and aromatic hydrocarbons, solid particles such as coal, catalyst powder, and sludge, as well as chemical pollutants such as organic matter, acid, and alkalinity.

[0098] Use the separation device given in Example 1 and the method of use given above to separate and treat the oily and solid-containing wastewater.

[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 / h flow rate enters the oil-solid synergistic separation device of cyclone coupling coalescence, and the pressure range of the device is adjusted to 0.1-0.3MPa. When the pressure reaches a stable value, read the readings of the magnetic flowmeter and pressure gauge at each inlet and outlet.

[0107] 4. Implementation effect analysis

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

[0109] The results show that the 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] The device also has a good effect on the removal of oil substances. From the results of the measured inlet and outlet oil contents, it can be seen that the inlet oil content is 450-500mg / L, and the outlet oil concentration of the water treated by the equipment is controlled below 50mg / L. The removal efficiency of emulsified oil and floating oil in water is more than 90%. The device maintains a high separation efficiency for the oil phase and suspended matter in the wastewater over a long period of time. The results show that the 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 1:3) enters the fiber unit from the backwash pipe to wash out suspended particles and residual oil. After the backwash is completed, part of the surface of the fiber unit 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, such as Fig.12 shown.

[0112] The results show that the initial residual rate of suspended matter is 11.3% on average, and the initial residual rate of oil content is 16.9% on average. As the backwash time increases, the content of suspended matter particles and oil droplets intercepted gradually decreases. When the backwash time is 35 minutes, the residual rate of suspended matter in the fiber unit decreases from 11.3% to 4.1%, and the residual rate of oil content in the fiber unit decreases from 16.9% to 6.07%. As time continues to increase, the residual rate of suspended matter and oil content in the fiber unit tends to stabilize, which indicates that the backwash effect is stable and effective and the optimal regeneration backwash time is 20 minutes. The backwash experiment shows that the fiber unit of this device has good regeneration.

Claims

1. An oil-solid synergistic separation device with cyclone coupling coalescence, characterized in that: It 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 arranged in the tank body; a feed port for introducing oil-containing and solid-containing wastewater is arranged on the tank body, a screw pump is connected to the feed port, and a volute flow channel communicating with the inside of the tank body is arranged around the outer periphery of the tank body with the feed port as the starting point; The cyclone separation structure comprises 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 part 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 comprises a spiral jacket extending downward from the volute flow channel as a starting point, and a collecting 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 liquid collecting plate is arranged above the fiber unit to help discharge the oil phase adsorbed in the fiber unit, the liquid collecting plate is arranged around the periphery of the backwash structure, a head is arranged above the liquid 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 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-oleophobic modified fibers and oleophilic-hydrophobic modified fibers. The stacking thickness of the fiber unit is 600-900 mm, and the fiber unit accounts for 70-90% 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 outwards from the center of the hydraulic pressure collecting plate as the origin, and 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, and the thickness of the hydraulic pressure collecting plate is 6-8 cm; an oil collecting cavity connected with the oil outlet pipe is provided in the sealing 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 vertically arranged with the backwash pipe and a water outlet pipe 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 synergistic separation device of cyclone coupling coalescence as claimed in any one of claims 1 to 8; comprising: (1) The wastewater containing oil and solid 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 solid 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 in order; (2) The sorted wastewater containing oil and solids enters the three-phase separation unit inside the tank body along the volute flow channel, and the spiral jacket in the three-phase separation unit is used to strengthen the separation of the water phase, the solid phase, and the oil phase, so that the water phase and the oil phase enter the water-oil separation unit, and the solid phase enters the collection unit and is discharged from the tank body; (3) The water phase and the oil phase that enter the water-oil separation unit enter the fiber unit through the openings, and the small oil droplets in the oil phase undergo wetting and agglomeration and collision and coalescence in the fiber unit to form large oil droplets, and then the oil phase on the upper part 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 tank body through the oil outlet pipe, and 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 a backwashing structure. After the backwashing 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- and solid-containing wastewater.

10. The method for oil-solid synergistic separation by cyclone-coupled coalescence as claimed in 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 matter in the wastewater containing oil and solids is ≥75%, and the removal rate of oil in the wastewater containing oil and solids is ≥90%.

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