Emulsified wastewater multi-cyclone flotation separator

Abstract

This invention belongs to the field of wastewater treatment technology, specifically relating to a multi-stage cyclone flotation separator for emulsified wastewater. The multi-stage cyclone flotation separator for emulsified wastewater includes: a coalescer for preliminary separation treatment of the emulsified wastewater; a sludge-water separation chamber connected to the outlet of the coalescer for settling the sludge phase in the emulsified wastewater; a cyclone flotation unit disposed above the sludge-water separation chamber, the inlet of which is connected to the sludge-water separation chamber; an oil-water separation chamber disposed above the cyclone flotation unit, with coalescing packing material disposed between the oil-water separation chamber and the cyclone flotation unit; and an oil collection tank and a water collection chamber connected to the oil-water separation chamber, the oil collection tank being located above the water collection chamber.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically, it relates to a multi-cyclone air flotation separator for emulsified wastewater. Background Technology

[0002] During oil and gas field production, a large amount of emulsified wastewater is generated. This wastewater contains crude oil, suspended particles, dissolved organic matter, and various inorganic salts, forming a complex and stable emulsion system. As oilfield exploitation progresses, the amount of emulsified wastewater generated is increasing, becoming an environmental and resource problem that urgently needs to be addressed.

[0003] With the continuous breakthroughs and widespread application of fracturing technology, unconventional oil and gas, such as shale oil and gas, are gradually being exploited on a large scale. During the production process, a large volume of fracturing flowback fluid is generated, containing guar gum, preservatives, breaker agents, petroleum hydrocarbons, and various other chemical additives. This fluid carries a significant amount of sand and solid impurities from the formation, exhibiting characteristics such as high emulsification, difficulty in oil-water separation, and large fluctuations in water quality. Typically, fracturing flowback fluid is transported to the integrated treatment station by tanker trucks for pretreatment before entering the station's processing system. Pretreatment removes solid impurities, suspended solids, and colloids to prevent direct contact with the production system from disrupting normal operation, consuming large amounts of treatment chemicals, and affecting the quality of the injected water.

[0004] Commonly used pretreatment methods mainly include magnetic separation, suspended sludge (SSF) process, and biological methods. Among them, magnetic separation consumes a large amount of magnetic powder, which is difficult to recover, resulting in high costs and large sludge production. The SSF process is greatly affected by water quality fluctuations and still requires the addition of flocculants and coagulants to form flocs, making it difficult to control the sludge layer effect. Fracturing flowback fluid has poor biodegradability, requiring the addition of certain nutrients, resulting in high treatment costs, and the treatment effect is greatly affected by water temperature and ambient temperature.

[0005] Therefore, there is an urgent need for emulsified wastewater treatment technology to efficiently treat emulsified wastewater, such as fracturing backflow fluid, in order to meet purification and environmental protection requirements. Summary of the Invention

[0006] To address the technical problems described above, this invention aims to provide a multi-cyclone flotation separator for emulsified wastewater, which is applicable to the separation and treatment of oil and cement in wastewater generated from fracturing, drilling, acidizing, and well washing operations in oil and gas fields.

[0007] According to the present invention, a multi-cyclone flotation separator for emulsified wastewater is provided, comprising:

[0008] The coalescer is used for preliminary separation and treatment of emulsified wastewater.

[0009] A mud-water separation chamber connected to the outlet of the coalescer allows the mud phase in the emulsified wastewater to settle.

[0010] A cyclone flotation device is installed above the mud-water separation chamber, and the inlet of the cyclone flotation device is connected to the mud-water separation chamber.

[0011] An oil-water separation chamber is disposed above the cyclone flotation unit, and coalescing packing is disposed between the oil-water separation chamber and the cyclone flotation unit; and

[0012] An oil collecting tank and a water collecting chamber are connected to the oil-water separation chamber, with the oil collecting tank located above the water collecting chamber.

[0013] In one specific embodiment, the device further includes a housing, within which a separator cylinder is coaxially arranged. The coalescer includes a variable-diameter spiral coalescing tube, and a plurality of the variable-diameter spiral coalescing tubes are uniformly arranged circumferentially within the separator cylinder. The outlet of each of the variable-diameter spiral coalescing tubes passes through the separator cylinder and connects to the mud-water separation chamber.

[0014] In one specific embodiment, a water inlet distribution hopper is provided at the central axis of the separator cylinder, and the upper port of each of the variable diameter spiral coalescing tubes is connected to the water inlet distribution hopper, and a water inlet pipe is connected to the water inlet distribution hopper.

[0015] In one specific embodiment, an annular dosing distribution pipe is coaxially arranged inside the partition cylinder. Multiple dosing trunks, each corresponding to a variable-diameter spiral coalescing pipe, are spaced circumferentially along the dosing distribution pipe. The central axis of each dosing trunk coincides with the spiral axis of its corresponding variable-diameter spiral coalescing pipe. The dosing trunk is connected to the variable-diameter spiral coalescing pipe via at least one dosing branch pipe, the diameter of which is smaller than that of the variable-diameter spiral coalescing pipe. A dosing inlet pipe is connected to the dosing distribution pipe.

[0016] In one specific embodiment, a partition plate is sealed between the partition cylinder and the side wall of the outer shell, and the bottom of the outer shell is configured as a mud phase guide cone. The partition plate, the side wall of the outer shell, and the mud phase guide cone form the mud-water separation chamber.

[0017] In one specific embodiment, a mud collection trough is provided at the lowest point of the mud phase guide cone, a mud sliding plate is provided at the upper part of the mud collection trough, and a mud sliding port is provided on the mud sliding plate. Under the action of gravity, the mud phase enters the mud collection trough along the mud sliding plate and through the mud sliding port. A mud discharge pipe is provided in the mud collection trough.

[0018] In one specific embodiment, the lowest point of the mud phase guide cone is located at the junction of the mud phase guide cone and the separator cylinder, the mud collection trough is configured as an annular structure coaxially arranged at the bottom of the outer shell, and a baffle is provided at the position corresponding to the outlet of the variable diameter spiral coalescing pipe in the mud-water separation chamber, the baffle being located above the mud collection trough.

[0019] In one specific embodiment, the swirl air flotation device includes swirl air flotation tubes, a plurality of swirl air flotation tubes are evenly distributed circumferentially between the partition cylinder and the side wall of the outer shell, and an air main pipe is coaxially arranged at the helical axis of each swirl air flotation tube. The air main pipe is connected to the swirl air flotation tube through at least one air branch pipe. The diameter of the air branch pipe is smaller than the diameter of the swirl air flotation tube, and the upper end of the air main pipe is located in the air cavity at the top of the outer shell.

[0020] In one specific embodiment, the coalescing packing is located above the swirl flotation tube, between the sidewall of the separator and the outer shell, and the air dryer penetrates the coalescing packing.

[0021] In one specific embodiment, an oil collection groove is provided on the upper part of the side wall of the outer shell, the top of the separator cylinder is lower than the oil collection groove, the water collection chamber is located inside the separator cylinder, a water collection hole is provided on the side wall of the separator cylinder above the coalescing packing, a water collection guide cone is provided inside the separator cylinder at a position below the water collection hole, and a water collection center pipe is connected to the lower end of the water collection guide cone, the water collection center pipe is fixedly connected to the coalescer.

[0022] Compared with the prior art, the advantages of this application are as follows.

[0023] This invention provides a multi-cyclone air flotation separator for emulsified wastewater, which couples multi-cyclone air flotation, coalescence, and mud-water separation technologies. It is particularly suitable for demulsification and oil-cement separation of operational wastewater with high emulsification and many impurities, such as fracturing flowback fluid. It features high efficiency, continuous operation, low dosage, or even no dosage.

[0024] The present invention features a separator cylinder in the middle of the outer shell, a coalescer inside the separator cylinder, a mud-water separation chamber between the separator cylinder and the outer shell, and multiple variable-diameter spiral coalescing tubes evenly distributed circumferentially inside the separator cylinder, and multiple swirling flotation tubes evenly distributed circumferentially in the annulus between the separator cylinder and the outer shell. This special structural arrangement improves the wastewater treatment efficiency.

[0025] The outer shell of this invention is sealed. Emulsified wastewater enters the outer shell of the emulsified wastewater multi-cyclone flotation separator through the inlet pipe. After treatment, it is discharged through the outlet pipe connected to the end of the water collection center pipe. The gas used by the cyclone flotation device is the gas in the air chamber at the top of the outer shell. Therefore, the emulsified wastewater will not come into contact with the outside world during the treatment process, which can eliminate the problems of VOCs volatilization and dissolved oxygen corrosion. Attached Figure Description

[0026] The present invention will now be described with reference to the accompanying drawings.

[0027] Figure 1This is a schematic diagram of an embodiment of the multi-cyclone flotation separator for emulsified wastewater according to the present invention.

[0028] Figure 2 This is an enlarged schematic diagram of the cyclone flotation unit in the multi-cyclone flotation separator for emulsified wastewater according to the present invention.

[0029] Figure 3 This is an enlarged schematic diagram of the coalescer of the multi-cyclone flotation separator for emulsified wastewater proposed in this invention.

[0030] In the picture:

[0031] 1. Inlet pipe; 2. Inlet distribution hopper; 3. Coalescer; 31. Variable diameter spiral coalescing pipe; 32. Dosing branch pipe; 33. Dosing inlet pipe; 34. Dosing distribution pipe; 35. Dosing main pipe; 36. Coalescer outlet; 4. Sludge-water separation chamber; 41. Baffle; 42. Divider plate; 5. Sludge collection trough; 51. Sludge sliding plate; 52. Sludge sliding port; 53. Sludge phase guide cone; 54. Sludge discharge pipe; 6. Swirl Flotation unit; 61. Cyclone inlet; 62. Cyclone flotation tube; 63. Air branch pipe; 64. Air main pipe; 65. Cyclone outlet; 7. Oil-water separation chamber; 71. Coalescing packing; 72. Oil collection tank; 9. Water collection chamber; 91. Separator cylinder; 92. Water collection hole; 93. Water collection guide cone; 94. Water collection center pipe; 95. Water outlet pipe; 100. Multi-cyclone flotation separator for emulsified wastewater; 101. Outer shell.

[0032] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0033] The invention will now be described with reference to the accompanying drawings.

[0034] It should be noted that the directional terms or qualifiers such as "up" and "down" used in this application are all specific to the referenced [reference]. Figure 1 In other words, they are not used to define the absolute position of the components involved, but can vary depending on the specific circumstances.

[0035] Figure 1 The structure of the multi-cyclone flotation separator 100 for emulsified wastewater according to the present invention is shown. Figure 1 As shown, in this embodiment, the emulsified wastewater multi-cyclone flotation separator 100 includes a coalescer 3, which is used to perform preliminary separation treatment on the emulsified wastewater.

[0036] The emulsified wastewater multi-cyclone flotation separator 100 also includes a sludge-water separation chamber 4, and the outlet of the coalescer 3 is connected to the sludge-water separation chamber 4. After preliminary treatment by the coalescer 3, the emulsified wastewater enters the sludge-water separation chamber 4, and the sludge phase in the emulsified wastewater settles in the sludge-water separation chamber 4.

[0037] The emulsified wastewater multi-cyclone flotation separator 100 also includes a cyclone flotation unit 6, which is positioned above the sludge-water separation chamber 4, and its inlet is connected to the sludge-water separation chamber 4. After the sludge phase in the emulsified wastewater settles in the sludge-water separation chamber 4, the remaining aqueous and oil phases enter the cyclone flotation unit 6. Under the action of the cyclone flotation unit 6, the aqueous and oil phases in the emulsified wastewater are further separated.

[0038] The emulsified wastewater multi-cyclone flotation separator 100 also includes an oil-water separation chamber 7, which is located above the cyclone flotation unit 6, and a coalescing packing 71 is placed between the oil-water separation chamber 7 and the cyclone flotation unit 6. After the aqueous and oil phases in the emulsified wastewater are separated by the cyclone flotation unit 6, they pass through the coalescing packing 71 and enter the oil-water separation chamber 7. The coalescing packing 71 can further rectify the emulsified wastewater and coalesce the oil droplets.

[0039] The emulsified wastewater multi-cyclone flotation separator 100 also includes an oil collection tank 72 and a water collection chamber 9 connected to the oil-water separation chamber 7, with the oil collection tank 72 located above the water collection chamber 9. After the aqueous and oil phases in the emulsified wastewater enter the oil-water separation chamber 7 through the coalescing packing 71, the aqueous and oil phases separate into layers. The oil phase is discharged through the oil collection tank 72, and the aqueous phase is discharged through the water collection chamber 9.

[0040] According to a specific embodiment of the present invention, the emulsified wastewater multi-cyclone flotation separator 100 includes an outer shell 101, which is a closed shell with an overall generally cylindrical shape. A separator 91 is coaxially disposed inside the outer shell 101. The separator 91 is also generally cylindrical, with its lower end fixedly and sealed to the lower end of the outer shell 101, and a gap existing between the upper end of the separator 91 and the upper end of the outer shell 101.

[0041] The coalescer 3 includes variable-diameter spiral coalescing tubes 31. Multiple variable-diameter spiral coalescing tubes 31 are evenly spaced circumferentially within the separator 91, with the spiral axis of each tube parallel to the central axis of the separator 91. In this embodiment, 4-8 variable-diameter spiral coalescing tubes 31 are connected sequentially. The overall structure of each tube is roughly spring-like. The lower end of each tube is designated as the coalescer outlet 36. The lower end of each tube passes through the separator 91 and connects to the sludge-water separation chamber 4. Emulsified wastewater enters from the upper end of the variable-diameter spiral coalescing tube 31 and finally flows out from the lower end of the tube through the coalescer outlet 36, thus flowing into the sludge-water separation chamber 4.

[0042] In a preferred embodiment, the coalescer outlet 36 of the variable diameter spiral coalescing pipe 31 points toward the baffle 41, the structure of which is detailed below.

[0043] According to the present invention, in this embodiment, an inlet distribution hopper 2 is provided at the central axis of the separator 91, and the upper ports of each variable-diameter spiral coalescing tube 31 are connected to the inlet distribution hopper 2. An inlet pipe 1 is connected to the inlet distribution hopper 2. Specifically, the upper ports of each variable-diameter spiral coalescing tube 31 are connected to the side of the inlet distribution hopper 2 in a circumferential direction. One end of the inlet pipe 1 is connected to the lower end of the inlet distribution hopper 2, and the other end of the inlet pipe 1 passes radially through the separator 91 and the outer shell 101 to extend to the outside of the outer shell 101. In this configuration, when treating emulsified wastewater, the emulsified wastewater enters the inlet distribution hopper 2 through the inlet pipe 1, and under the distribution of the inlet distribution hopper 2, the emulsified wastewater enters each variable-diameter spiral coalescing tube 31 respectively. After being pressurized, the emulsified wastewater (including but not limited to fracturing flowback fluid, drilling, acidizing, well washing wastewater, and chemical flooding produced water in this invention) enters the water distribution hopper 2 through the water inlet pipe 1 for water distribution and flows into the coalescer 3. Pressurization can increase centrifugal force and help improve the swirling effect. When the oil-water emulsification is not severe, the treatment process is as follows: The main structure in the coalescer 3 is a variable diameter spiral coalescing tube 31 similar to a spring shape. The emulsified wastewater undergoes swirling. Due to the density difference, under the action of centrifugal force, the oil phase is close to the inner side of the variable diameter spiral coalescing tube 31, and the water and solid phases are close to the outer side of the variable diameter spiral coalescing tube 31. Since the diameter of the variable diameter spiral coalescing tube 31 is constantly changing, it increases the chance of oil droplet collision and coalescence. When the emulsified wastewater is discharged from the coalescer outlet 36 at the lower end to the mud-water separation chamber 4, most of the floating oil and some dissolved oil and emulsified oil have been separated from the water.

[0044] According to a preferred embodiment of the present invention, an annular dosing distribution pipe 34 is coaxially arranged inside the separator 91. Multiple dosing trunk pipes 35, corresponding one-to-one with variable-diameter spiral coalescing pipes 31, are uniformly arranged circumferentially on the dosing distribution pipe 34. The central axis of each dosing trunk pipe 35 coincides with the spiral axis of its corresponding variable-diameter spiral coalescing pipe 31. The dosing trunk pipe 35 is connected to the variable-diameter spiral coalescing pipe 31 via at least one dosing branch pipe 32. A dosing inlet pipe 33 is connected to the dosing distribution pipe 34, and the dosing inlet pipe 33 passes radially through the separator 91 and the outer shell 101, extending to the outside of the outer shell 101. With this arrangement, chemicals, such as demulsifiers, or alternating demulsifiers and flocculants, can be added to the variable-diameter spiral coalescing pipes 31 through the dosing inlet pipe 33, thereby improving the treatment effect on emulsified wastewater.

[0045] Preferably, multiple dosing branch pipes 32 are evenly arranged from top to bottom along the central axis of the dosing main pipe 35. Each dosing branch pipe 32 is connected at both ends to the dosing main pipe 35 and the variable-diameter spiral coalescing pipe 31, respectively. The diameter of the dosing branch pipe 32 is smaller than the diameter of the variable-diameter spiral coalescing pipe 31. Furthermore, the diameter of the dosing branch pipe 32 is much smaller than the diameter of the variable-diameter spiral coalescing pipe 31, forming a Venturi tube structure at their connection. The chemical is drawn into the variable-diameter spiral coalescing pipe 31 by the high-speed wastewater flowing through it, primarily through the Venturi tube principle, resulting in excellent mixing. This arrangement allows for a reduction in the amount of chemical required while achieving the same effect.

[0046] According to a specific embodiment of the present invention, a partition plate 42 is sealed between the partition cylinder 91 and the side wall of the outer shell 101, and the partition plate 42 divides the annular space between the partition cylinder 91 and the outer shell 101 into upper and lower parts. The bottom of the outer shell 101 is configured as a mud phase guide cone 53, and the partition plate 42, the side wall of the outer shell 101 and the mud phase guide cone 53 form a mud-water separation chamber 4.

[0047] The mud phase guide cone 53 is a cone-shaped structure with a lower center and higher edges. A mud collection trough 5 is located at the lowest point of the mud phase guide cone 53, and a mud sliding plate 51 is located at the upper part of the mud collection trough 5. A mud sliding opening 52 is provided on the mud sliding plate 51. Under the action of gravity, the mud phase flows along the mud sliding plate 51 and through the mud sliding opening 52 into the mud collection trough 5. A mud discharge pipe 54 is installed inside the mud collection trough 5. The mud sliding plate 51 and the mud sliding opening 52 prevent the flow of wastewater in the mud-water separation chamber 4 from affecting the mud phase deposited in the mud collection trough 5. The mud phase deposited in the mud collection trough 5 can be discharged by periodically opening the mud discharge pipe 54.

[0048] In this embodiment, the lowest point of the mud phase guiding cone 53 is located near the junction of the mud phase guiding cone 53 and the separator 91. That is, the mud collection trough 5 is located near the junction of the mud phase guiding cone 53 and the separator 91, and the mud collection trough 5 is configured as an annular structure coaxially mounted at the bottom of the outer casing 101. A baffle 41 is provided at the outlet of the variable diameter spiral coalescing pipe 31 of the mud-water separation chamber 4, located above the mud collection trough 5. With this configuration, after the emulsified wastewater flows out of the variable diameter spiral coalescing pipe 31, it encounters the baffle 41, which acts as a flow straightener, preventing the high-speed water flow from impacting the sedimentation process of the oil and cement in the mud-water separation chamber 4. This accelerates the separation process; after the wastewater flow impacts the baffle 41, some of the mud and sand separate from the oil and water, and can sink into the mud collection trough 5 directly below the baffle 41 at the fastest speed and along the shortest path. Part of the mud phase in the wastewater flows through the mud phase guide cone 53 to the mud sliding plate 51, and finally enters the mud collection tank 5. The mud sliding port 52 ensures that flocs, sludge, and large-diameter solids enter the mud collection tank 5 quickly, preventing the flow field above from disturbing the settled sludge and causing it to be carried back into the aqueous phase. After mud-water separation, the sludge is concentrated in the mud collection tank 5. As the amount of sludge increases, the aqueous phase is squeezed out of the mud sliding port 52 from the mud collection tank 5, continuously reducing the sludge moisture content and lowering subsequent transportation and treatment costs.

[0049] In a preferred embodiment, the mud discharge pipe 54 is configured as an annular shape that matches the shape of the annular mud collection trough 5. Multiple perforations are provided on the pipe wall of the mud discharge pipe 54, and the mud discharge pipe 54 is connected to a negative pressure device. The negative pressure device is periodically turned on to allow the mud phase in the mud collection trough 5 to enter the mud discharge pipe 54 through the perforations and finally be discharged through the mud discharge pipe 54 and the negative pressure device.

[0050] In a preferred embodiment, the baffle 41 is constructed in a circular shape, that is, the baffle 41 is coaxially arranged inside the housing 101, and the wastewater flowing out of the coalescing outlet 36 of each variable diameter spiral coalescing tube 31 can impact the baffle 41 head-on.

[0051] According to a specific embodiment of the present invention, the cyclone flotation device 6 includes cyclone flotation tubes 62. Multiple cyclone flotation tubes 62 are evenly distributed circumferentially between the partition cylinder 91 and the sidewalls of the outer shell 101. The lower port of each cyclone flotation tube 62 is a cyclone inlet 61, and the upper port is a cyclone outlet 65. The cyclone flotation tubes 62 are located above the partition plate 42. The cyclone inlet 61 of the cyclone flotation tube 62 passes downward through the partition plate 42, and the wastewater in the sludge-water separation chamber 4 continues to enter the cyclone flotation tube 62 through the cyclone inlet 61, and finally flows out from the cyclone outlet 65.

[0052] Furthermore, an air main pipe 64 is coaxially arranged at the helical axis of each cyclone flotation tube 62. The air main pipe 64 is connected to the cyclone flotation tube 62 through at least one air branch pipe 63. The upper end of the air main pipe 64 is located in the air cavity at the top of the outer shell 101. The oil phase and water phase in the wastewater pass through the cyclone inlet 61 and the partition plate 42 at the top of the sludge-water separation chamber 4 into multiple radially and circumferentially symmetrically arranged cyclone flotation tubes 62, where cyclone flotation occurs. The flotation air comes from the gas in the air cavity at the top of the outer shell 101 and can be self-circulated. Specifically, the gas in the air cavity at the top of the outer shell 101 enters the air main pipe 64 and then enters the cyclone flotation tube 62 along the air branch pipe 63.

[0053] According to the present invention, a plurality of air branch pipes 63 are arranged axially at intervals on the air main pipe 64, and the two ends of each air branch pipe 63 are respectively connected to the air main pipe 64 and the swirl air float pipe 62.

[0054] In a preferred embodiment, the diameter of the cyclone flotation tube 62 decreases from the cyclone inlet 61 to the cyclone outlet 65, and the corresponding diameter of the air branch tube 63 also decreases. According to the present invention, the diameter of the air branch tube 63 is smaller than the diameter of the cyclone flotation tube 62; furthermore, the diameter of the air branch tube 63 is much smaller than the diameter of the cyclone flotation tube 62, thus forming a Venturi tube structure. This allows for the high-speed water flow to draw in the gas, fully mixing the gas with the wastewater within the cyclone flotation tube 62, forming cyclone flotation within the cyclone flotation tube 62. The oil droplet-bubble complex is located on the inner side of the cyclone flotation tube 62, while the water phase is closer to the outer side. Due to the gradually narrowing flow channel design of the cyclone flotation tube 62 (i.e., the diameter of the cyclone flotation tube 62 decreases from the cyclone inlet 61 to the cyclone outlet 65), the cyclone intensity increases, and oil-water separation is completed when the oil, water, and gas flow out from the cyclone outlet 65.

[0055] The air cavity at the top of the outer shell 101 is the space cavity above the oil collection tank 72. The annular oil collection tank 72 set on the outer shell 101 is fixed. The liquid level reaches the oil collection tank 72. There is always a gas phase space at the top of the outer shell 101 for swirling air flotation, thus having self-circulating air supply without relying on external gas sources such as nitrogen or natural gas.

[0056] According to a specific embodiment of the present invention, a coalescing packing 71 is disposed between the sidewalls of the separator 91 and the outer shell 101. The coalescing packing 71 is located above the cyclone flotation device 6, and the air main pipe 64 passes through the coalescing packing 71. The space above the coalescing packing 71 is the oil-water separation chamber 7. After the wastewater flows out from the cyclone outlet 65 of the cyclone flotation pipe 62, the separated oil-water mixture is further rectified and the oil droplets coalesce through the coalescing packing 71, and then enters the oil-water separation chamber 7 to achieve oil-water stratification.

[0057] In one specific embodiment, an oil collecting groove 72 is provided on the upper part of the side wall of the outer casing 101, and the top of the separator cylinder 91 is lower than the oil collecting groove 72. In this embodiment, the oil collecting groove 72 is configured as annular and coaxially fixed on the side wall of the outer casing 101.

[0058] The water collection chamber 9 is located inside the partition cylinder 91. A water collection hole 92 is provided on the side wall of the partition cylinder 91 above the coalescing packing 71. A water collection guide cone 93 is provided inside the partition cylinder 91 below the water collection hole 92. A water collection center pipe 94 is connected to the lower end of the water collection guide cone 93. The water collection center pipe 94 extends downward to the location of the coalescer 3 and is fixedly connected to the coalescer 3. Specifically, the water collection center pipe 94 passes through the water inlet distribution hopper 2, and the two are not interconnected. The water collection center pipe 94 is fixedly connected to the water inlet distribution hopper 2, thereby providing support for the water inlet distribution hopper 2. This allows each variable diameter spiral coalescing tube 31 of the coalescer 3 to be fixedly connected to the water collection center pipe 94 through the water inlet distribution hopper 2.

[0059] According to the present invention, a water outlet pipe 95 is provided at the lower part of the water collection center pipe 94. The water outlet pipe 95 passes through the partition cylinder 91 and the outer shell 101 in a radial direction, thereby extending to the outside of the outer shell 101.

[0060] The oil phase after separation of wastewater in the oil-water separation chamber 7 is located above the water phase. The separated oil phase enters the fixed oil collection tank 72, and the water phase enters the water collection chamber 9 through the water collection hole 92. Then, it is discharged from the outer shell 101 through the water collection guide cone 93, the water collection center pipe 94 and the water outlet pipe 95 in sequence.

[0061] The top of the separator 91 is open, and the top of the separator 91 is lower than the oil collection tank 72. The water collection guide cone 93 has a long length to ensure that the oil droplets entering the water collection chamber 9 from the water collection hole 92 have enough vertical height to float to the top oil layer and avoid contaminating the effluent water quality.

[0062] According to a specific embodiment of the present invention, the structure of the emulsified wastewater multi-cyclone flotation separator 100 is as follows: The outer shell 101 has dimensions of Φ15000×12000mm, and a treatment efficiency of 1000~2000m³ / h. 3 / d. Four coalescers 3 are evenly arranged at 90° intervals around the circumference inside the separator cylinder 91 of the outer shell 101. The height of the variable-diameter spiral coalescing tube 31 of the coalescer 3 is 2500mm, the diameter is 1000mm, the number of stages is 20, and the spiral diameter is DN50~100. The dosing main pipe 35 is DN32, the dosing distribution pipe 34 is DN32, and the dosing branch pipe 32 is DN15. There are 17 dosing branch pipes 32. Above the separator plate 42, 3×8=24 groups of cyclone flotation units 6 are arranged radially symmetrically at 45°. The height of the cyclone flotation tube 62 of each cyclone flotation unit 6 is 1800mm, the diameter is 500mm, the number of stages is 15, and the diameter of the cyclone flotation tube 62 is DN32~65. The air main pipe 64 is DN32, and the air branch pipe 63 is DN15~DN32. There are 10 air branch pipes 63. The wastewater from the operation and the produced water from chemical flooding are pressurized to 0.7-1.0 MPa by the booster pump, which prompts the coalescer 3 and the cyclone flotation unit 6 to make full use of centrifugal force to perform coalescence, chemical dosing, and flotation to remove oil, thereby achieving oil-cement separation.

[0063] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0064] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-cyclone flotation separator for emulsified wastewater, characterized in that, include: The coalescer (3) performs preliminary separation treatment on the emulsified wastewater; The mud-water separation chamber (4), which is connected to the outlet of the coalescer (3), causes the mud phase in the emulsified wastewater to settle. A cyclone flotation device (6) is installed above the mud-water separation chamber (4), and the inlet of the cyclone flotation device (6) is connected to the mud-water separation chamber (4). An oil-water separation chamber (7) is provided above the cyclone flotation device (6), and a coalescing packing (71) is provided between the oil-water separation chamber (7) and the cyclone flotation device (6). as well as An oil collecting trough (72) and a water collecting chamber (9) are connected to the oil-water separation chamber (7), with the oil collecting trough (72) located above the water collecting chamber (9).

2. The emulsified wastewater multi-cyclone flotation separator according to claim 1, characterized in that, It also includes a housing (101), and a separator (91) is coaxially arranged inside the housing (101). The coalescer (3) includes a variable diameter spiral coalescing tube (31). A plurality of the variable diameter spiral coalescing tubes (31) are evenly arranged in the separator (91) along the circumference. The outlet of each variable diameter spiral coalescing tube (31) passes through the separator (91) and connects to the mud-water separation chamber (4).

3. The emulsified wastewater multi-cyclone flotation separator according to claim 2, characterized in that, A water inlet distribution hopper (2) is provided at the central axis of the separator (91). The upper port of each of the variable diameter spiral coalescing pipes (31) is connected to the water inlet distribution hopper (2). A water inlet pipe (1) is connected to the water inlet distribution hopper (2). The water inlet pipe (1) extends to the outside of the outer shell (101).

4. The emulsified wastewater multi-cyclone flotation separator according to claim 2, characterized in that, An annular dosing distribution pipe (34) is coaxially arranged inside the partition cylinder (91). Multiple dosing trunks (35) corresponding to the variable diameter spiral coalescing pipe (31) are arranged circumferentially on the dosing distribution pipe (34). The central axis of each dosing trunk (35) coincides with the spiral axis of its corresponding variable diameter spiral coalescing pipe (31). The dosing trunk (35) is connected to the variable diameter spiral coalescing pipe (31) through at least one dosing branch pipe (32). The diameter of the dosing branch pipe (32) is smaller than the diameter of the variable diameter spiral coalescing pipe (31). A dosing inlet pipe (33) is connected to the dosing distribution pipe (34).

5. The emulsified wastewater multi-cyclone flotation separator according to any one of claims 2 to 4, characterized in that, A partition plate (42) is sealed between the partition cylinder (91) and the side wall of the outer shell (101). The bottom of the outer shell (101) is configured as a mud phase guide cone (53). The partition plate (42), the side wall of the outer shell (101) and the mud phase guide cone (53) form the mud-water separation chamber (4).

6. The emulsified wastewater multi-cyclone flotation separator according to claim 5, characterized in that, A mud collection trough (5) is provided at the lowest point of the mud phase guide cone (53), a mud sliding plate (51) is provided at the upper part of the mud collection trough (5), a mud sliding port (52) is provided on the mud sliding plate (51), and the mud phase enters the mud collection trough (5) along the mud sliding plate (51) and through the mud sliding port (52) under the action of gravity. A mud discharge pipe (54) is provided in the mud collection trough (5).

7. The emulsified wastewater multi-cyclone flotation separator according to claim 6, characterized in that, The lowest point of the mud phase guide cone (53) is located at the junction of the mud phase guide cone (53) and the separator (91). The mud collection tank (5) is configured as an annular structure coaxially arranged at the bottom of the outer shell (101). A baffle (41) is provided at the position of the mud-water separation chamber (4) corresponding to the outlet of the variable diameter spiral coalescing pipe (31). The baffle (41) is located above the mud collection tank (5).

8. The emulsified wastewater multi-cyclone flotation separator according to any one of claims 2 to 4, characterized in that, The swirl air flotation device (6) includes swirl air flotation tubes (62). Multiple swirl air flotation tubes (62) are evenly distributed circumferentially between the partition cylinder (91) and the side wall of the outer shell (101). An air main pipe (64) is coaxially arranged at the helical axis of each swirl air flotation tube (62). The air main pipe (64) is connected to the swirl air flotation tube (62) through at least one air branch pipe (63). The diameter of the air branch pipe (63) is smaller than the diameter of the swirl air flotation tube (62). The upper end of the air main pipe (64) is located in the air cavity at the top of the outer shell (101).

9. The emulsified wastewater multi-cyclone flotation separator according to claim 8, characterized in that, The coalescing packing (71) is located above the swirl air flotation tube (62) and is disposed between the side wall of the separator (91) and the outer shell (101). The air dryer (64) passes through the coalescing packing (71).

10. The emulsified wastewater multi-cyclone flotation separator according to any one of claims 2 to 4, characterized in that, An oil collection trough (72) is provided on the upper part of the side wall of the outer shell (101). The top of the separator cylinder (91) is lower than the oil collection trough (72). The water collection chamber (9) is located inside the separator cylinder (91). A water collection hole (92) is provided on the side wall of the separator cylinder (91) above the coalescing packing (71). A water collection guide cone (93) is provided inside the separator cylinder (91) at a position lower than the water collection hole (92). A water collection center pipe (94) is connected to the lower end of the water collection guide cone (93). The water collection center pipe (94) is fixedly connected to the coalescer (3). The water collection center pipe (94) extends to the outside of the outer shell (101).

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