Two-chamber two-way ultrasonic, coalescing oil-water separation method and device

Abstract

The application discloses a two-chamber bidirectional ultrasonic and coalescence oil-water separation method and device, which comprises a vertical tank body, an ultrasonic transducer, a bidirectional water inlet pipe, a water outlet pipe, an oil outlet pipe, an ultrasonic generator and a flow direction switching device and the like. According to the oil-bearing produced water quality, the method switches and selects the coalescence mode of the ultrasonic demulsification in the forward flow and the reverse flow modes, and simultaneously, auxiliary micro-aeration is used to strengthen the oil droplet floating speed and promote the self-cleaning of the coalescence material. The problems of the coalescence material pollution, low treatment efficiency and large maintenance workload caused by the single flow direction are overcome. The oil-bearing produced water after treatment can be effectively separated into oil, water and solid three phases, the treatment requirements are met, the effective use time of the coalescence material is prolonged, and the maintenance workload is reduced.

Description

Technical Field

[0001] This invention belongs to the field of water treatment, specifically relating to a two-chamber bidirectional ultrasonic coalescing oil-water separation method and apparatus. Background Technology

[0002] In recent years, with the vigorous development of oil extraction, the environmental protection situation has become increasingly severe. The reinjection of treated oilfield produced water into the formation for oil displacement is crucial to avoiding formation blockage and has received high attention. Currently, the main oilfield produced water treatment technologies include sedimentation, biochemical treatment, flotation, and filtration.

[0003] Sedimentation is often used as the first-stage process in produced water treatment, initially achieving oil-water separation and suspended solids sedimentation, reducing the load on subsequent flotation, biological, and filtration processes. The principle of sedimentation oil removal mainly utilizes the density difference between oil and water, achieving separation through static sedimentation or slow flow. It primarily separates floating oil and finely dispersed oil in the water. However, for produced water containing polymers and shale oil, the oil in the water often exists in a stable emulsion state of oil-in-water or water-in-oil, resulting in very low separation efficiency of the sedimentation process. This leads to a heavy load on subsequent processes and makes reinjection unsatisfactory. With the development of oil production technology in recent years, ultrasonic demulsification and coalescence oil removal processes have gradually gained widespread application due to their good demulsification effect and wide adaptability.

[0004] CN202400923U discloses an ultrasonic coalescing flotation oil removal device, including a tank body, an inlet at one end of the tank body, and an outlet at the other end opposite to the inlet. An ultrasonic pulse system, a coalescing packing zone, and a flotation system are sequentially arranged in the tank body along the water flow direction.

[0005] CN112479452A discloses an ultrasonic coalescing oil-water separation device, which includes a coarse separation chamber and a fine separation chamber. The fine separation chamber is located on the upper part of the top partition of the coarse separation chamber. An ultrasonic coalescing packing area is located outside the partition on one side of the coarse separation chamber. An ultrasonic transducer is installed at the axial center of the ultrasonic coalescing packing area. The fine separation chamber is divided into a lower effluent buffer zone and an upper sludge and oil zone.

[0006] All of the above technologies employ a fixed flow direction, either co-current or counter-current. Each direction has its advantages and disadvantages. In co-current flow, the water flow direction is the same as the oil droplet direction. After ultrasonic treatment, the water flows through the entire coalescing layer, resulting in a longer coalescing time, which is beneficial for oil droplet floating. However, suspended solids and mechanical impurities easily adhere to the interior of the coalescing layer, leading to contamination and failure of the coalescing material after a period of operation. Therefore, it is suitable for water with low oil content. In counter-current flow, the water flow direction is opposite to the oil droplet direction. Small oil droplets coalesce into larger droplets and then float to the surface. The descending water carries away mechanical impurities from the surface of the coalescing material, providing a certain degree of cleaning. This is more suitable for water with higher oil content. Currently, the fixed flow direction process cannot adjust the ultrasonic coalescing flow direction according to the varying oil content in the sampled water when there are large fluctuations in water quality. This results in the coalescing material being easily contaminated and difficult to clean, affecting the effectiveness of ultrasonic waves and coalescing, and causing the oil-water separation effect to gradually deteriorate after a period of operation. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the pollution problem of coalescing materials caused by the single flow direction in the prior art. The present invention provides a two-chamber bidirectional ultrasonic coalescing oil-water separation method and device. The oily produced water after treatment can effectively achieve three-phase separation of oil, water and solid, meet the treatment requirements, extend the effective service life of coalescing materials and reduce maintenance workload.

[0008] The present invention is achieved using the following technical solution:

[0009] A two-chamber bidirectional ultrasonic coalescing oil-water separator includes a vertical tank, an ultrasonic transducer, a diverting water inlet pipe, an ultrasonic generator, and a flow direction switching device.

[0010] The vertical tank is divided into two chambers by a weir plate: an ultrasonic coalescence chamber and an oil-water separation chamber. An integrated coalescence packing area is set in the middle of the ultrasonic coalescence chamber.

[0011] Water distributors / collectors are installed at the top and bottom of both the ultrasonic coalescence chamber and the oil-water separation chamber. The ultrasonic transducer is installed outside the vertical tank, at the same height as the water distributors / collectors at the top and bottom. The ultrasonic transducer is connected to the ultrasonic generator.

[0012] The flow direction switching device is used to split the water inlet pipe into two directions, upper and lower, and then enter the ultrasonic coalescence chamber of the vertical tank through the water distributor / collector;

[0013] A U-shaped pipe is connected to the upper middle part of the oil-water separation chamber, and an oil collection weir is set in the upper part of the oil-water separation chamber, with an oil outlet at the bottom of the oil collection weir.

[0014] A further improvement of the present invention is that the ultrasonic coalescence chamber is provided with a coalescence material, which is made of hydrophilic polyvinyl chloride or stainless steel.

[0015] A further improvement of the present invention is that the flow direction switching device includes an online oil content monitor, a co-current switching valve, a counter-current switching valve, and a control cabinet. The online oil content monitor is used to detect the oil content in the water and transmit it to the control cabinet. The control cabinet automatically opens or closes the co-current switching valve or the counter-current switching valve. One flow is co-current, entering the ultrasonic coalescing chamber from the bottom of the vertical tank, and the other flow is counter-current, entering the ultrasonic coalescing chamber from the top of the vertical tank.

[0016] A further improvement of the present invention is that both the co-current switching valve and the counter-current switching valve are electric valves.

[0017] A further improvement of the present invention is that the branch inlet pipe can be switched to the ultrasonic coalescence chamber outlet pipe in the counter-current state through the counter-current outlet switching valve.

[0018] A further improvement of the present invention is that a water outlet is provided in the lower part of the vertical tank.

[0019] A further improvement of the present invention is that a conical mud collection area is provided at the bottom of the vertical tank, and a mud discharge port is provided at the very bottom.

[0020] A further improvement of the present invention is that the sludge discharge port is connected to a sewage discharge pipe.

[0021] A further improvement of the present invention is that a micro-aerator is provided at the bottom of the ultrasonic coalescence chamber, which is connected to the micro-aeration pipe.

[0022] A two-chamber bidirectional ultrasonic coalescing oil-water separation method, the method being based on the aforementioned two-chamber bidirectional ultrasonic coalescing oil-water separation device, comprising:

[0023] Determination of oil content and properties in water;

[0024] When the oil content in the produced water is high, the flow direction switching device automatically switches to a counter-current flow. The produced water enters the vertical tank from the top inlet, and after ultrasonic demulsification, it flows counter-currently into the coalescing packing zone. Because oil is relatively light, most of the floating oil remains in the upper part of the coalescing packing zone and will not enter the coalescing material with the water flow, thus avoiding material contamination. After passing through the coalescing material, the emulsified oil and water flow by gravity into the upper part of the oil-water separation chamber through the U-shaped pipe. Due to the density difference between oil and water, according to the principle of the U-shaped pipe, the floating oil in the coalescing packing zone accumulates to a set thickness and reaches the upper part of the oil-water separation chamber through the weir plate.

[0025] When the oil content in the produced water is relatively low and the degree of emulsification is high, the flow direction switching device automatically switches to a co-current flow. The produced water enters the vertical tank from the lower inlet, is ultrasonically treated, and then flows co-currently into the coalescing packing area. The effluent enters the upper part of the oil-water separation chamber through the weir plate. The bidirectional inlet pipe is controlled by a switching valve to control the dual flow direction. When the bidirectional inlet pipe is simultaneously in a co-current state, it is the outlet pipe of the ultrasonic coalescing chamber.

[0026] After ultrasonication and coalescence, the water settles and separates in the oil-water separation chamber, achieving the desired treatment effect by separating the oil, water, and solid phases.

[0027] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0028] The present invention provides a two-chamber bidirectional ultrasonic coalescing oil-water separation device, which is divided into an ultrasonic coalescing chamber and an oil-water separation chamber. The ultrasonic coalescing chamber is provided with an upper ultrasonic zone, a lower ultrasonic zone and a middle coalescing zone. Through the mechanical vibration and thermal effect of unidirectional ultrasound, oil droplets and water droplets are caused to collide and aggregate under the action of the sound field. Then, through the coalescing material, the aggregated small oil droplets are formed into large oil droplets, which float to the surface to achieve oil-water separation. The oil content of produced water varies significantly depending on the water quality. When the oil content is high, the proportion of floating and dispersed oil is large. A counter-current flow with top inlet is adopted, and the oil layer formed after ultrasonic treatment floats directly to the surface. Produced water containing only a small amount of emulsified oil passes through the coalescence layer and coalesces again to the surface, avoiding contamination of the coalescence layer by floating and dispersed oil. When the oil content is low, the proportion of dispersed and emulsified oil is large. A co-current flow with bottom inlet is adopted. The produced water is demulsified by ultrasonic treatment and then flows co-currently through the entire coalescence layer, giving oil droplets sufficient time to form, grow, and aggregate, thereby achieving oil-water separation. Compared with single-direction ultrasonic coalescence, this method is more adaptable to different water qualities and can protect the coalescence layer and reduce contamination when the oil content is high, thus extending its service life. Micro-aeration is installed at the bottom of the device to increase turbulence in the coalescence zone. Micro-vibration reduces the adhesion of debris to the coalescence material, keeps the coalescence channel unobstructed, extends the coalescence service life, and reduces maintenance workload.

[0029] This invention provides a two-chamber, bidirectional ultrasonic coalescence oil-water separation method. This method achieves oil-water separation through the synergistic effect of ultrasound and coalescence. Ultrasound has mechanical vibration and thermal effects, causing oil and water droplets to collide and aggregate under the influence of the sound field. The coalescence material has the function of aggregating and growing small oil droplets into larger ones, and the oil droplets float to the surface, achieving oil-water separation. The technical features of this invention are that the ultrasonic coalescence chamber is equipped with upper and lower ultrasonic sections and a middle coalescence section. The influent automatically switches between co-current and counter-current ultrasonic coalescence flow directions based on the quality of the oil-bearing produced water. When the oil content is high, an upper influent counter-current flow is used, where the oil layer formed after ultrasound floats directly to the surface, while the produced water containing only a small amount of emulsified oil passes through the coalescence layer and coalesces again to the surface, avoiding contamination of the coalescence layer by floating and dispersed oil. When the oil content is low, a lower influent co-current flow is used, where the oil-bearing produced water is demulsified by ultrasound and then flows co-currently through the entire coalescence layer, providing sufficient time for oil droplet formation, growth, and aggregation, thereby improving the oil-water separation effect. The technical solution of this invention, with its two-chamber, dual-flow design, is more adaptable to different water quality conditions at different development stages. It facilitates flow direction switching, assists in micro-aeration self-cleaning function, is more conducive to oil-water separation, reduces pollution of coalescing materials, extends service life, and reduces maintenance workload.

[0030] In summary, this invention employs a bidirectional ultrasonic and coalescence method, automatically switching the ultrasonic coalescence flow direction according to water quality conditions, making it more adaptable to fluctuations in upstream water quality; the dual-chamber design allows for a more compact arrangement of ultrasonic, coalescence, and oil-water separation components; the coalescence packing area is equipped with micro-aeration and a self-cleaning function, extending the effective lifespan of the coalescence material and reducing maintenance workload. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a two-chamber bidirectional ultrasonic coalescence oil-water separation device according to the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Vertical tank, 2. Ultrasonic coalescence chamber, 3. Oil-water separation chamber, 4. Ultrasonic transducer, 5. Coalescing packing area, 6. Diverting water inlet pipe, 7. Micro-aeration pipe, 8. Water outlet pipe, 9. Oil outlet pipe, 10. Overflow pipe, 11. Sewage pipe, 12. Water distributor / collector, 13. Ultrasonic generator, 14. U-shaped pipe, 15. Weir plate, 16. Oil collection weir, 17. Oil outlet, 18. Water outlet, 19. Flow switching valve, 20. Counterflow switching valve, 21. Conical sludge collection area, 22. Sludge discharge port, 23. Micro-aerator, 24. Counterflow water outlet switching valve, 25. Online oil content monitor, 26. Control cabinet, 27. Flow direction switching device. Detailed Implementation

[0034] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] For ease of description, the words "up," "down," "left," and "right" appearing in this application only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] Terminology Explanation: The terms “installation,” “connection,” “linking,” and “fixing” used in this application should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction relationship between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] like Figure 1 As shown, the present invention provides a two-chamber bidirectional ultrasonic coalescing oil-water separation device, including a vertical tank 1, an ultrasonic coalescing chamber 2, an oil-water separation chamber 3, an ultrasonic transducer 4, a coalescing packing area 5, a branch inlet pipe 6, a micro-aeration pipe 7, a water outlet pipe 8, an oil outlet pipe 9, an overflow pipe 10, and a sewage discharge pipe 11, and also includes a flow direction switching device 27 and its control cabinet 26.

[0039] The tank is equipped with an overflow port and connected to an overflow pipe 10. The overflow pipe is 100-200mm higher than the normal operating liquid level in the tank. When the water or oil outlet pipes of the treatment device are blocked due to abnormal conditions, the liquid level rises and flows out from the overflow port to prevent the tank from overflowing.

[0040] The vertical tank 1 of the two-chamber bidirectional ultrasonic coalescence oil-water separation device is divided into two chambers by a weir plate 15: an ultrasonic coalescence chamber 2 and an oil-water separation chamber 3. In the ultrasonic coalescence chamber 2, the mechanical vibration and thermal effect of ultrasonic waves, as well as the coarsening effect of the coalescing material on the oil droplets, are used to increase the kinetic energy and thermal motion of the dispersed oil and emulsified oil in the oil-bearing produced water, promote the collision opportunities between particles, and thus utilize the affinity between the same particles to accelerate the ultrasonic demulsification and coalescence process of the oil-bearing produced water, thereby improving the oil-water separation effect.

[0041] The ultrasonic coalescing chamber 2 has an integrated coalescing packing area 5 in the middle, which facilitates the filling and replacement of the coalescing material. The coalescing material is made of regular hydrophilic polyvinyl chloride and stainless steel. The ultrasonic transducer 4 is installed on the outside of the vertical tank 1, at the same height as the upper and lower water inlet distributors / collectors 12. The ultrasonic transducer 4 is connected to the ultrasonic generator 13.

[0042] The flow direction switching device 27 splits the water inlet pipe 6 into two directions, upper and lower, which enter the ultrasonic coalescence chamber 2 of the vertical tank 1. The flow direction switching device 27 includes an online oil content monitor 25, a co-current switching valve 19, a counter-current switching valve 20, and a control cabinet 26. Based on the online oil content monitoring data, the control cabinet 26 automatically opens or closes the co-current switching valve 19 or the counter-current switching valve 20. One path is a co-current flow, entering from the bottom of the vertical tank 1, and the other is a counter-current flow, entering from the top of the vertical tank 1. A water distributor / collector 12 is provided at the water inlet.

[0043] When the oil content in the produced water is high, a counter-current flow is adopted. The co-current switching valve 19 is closed, and the counter-current switching valve 20 is opened. The produced water enters the vertical tank 1 from the upper inlet, and after ultrasonic demulsification, flows counter-currently into the coalescing packing zone 5. Because oil is relatively light, most of the floating oil will remain in the upper part of the coalescing packing zone 5 and will not enter the coalescing material with the water flow, thus avoiding material contamination. After passing through the coalescing material, the emulsified oil and water flow by gravity into the upper part of the oil-water separation chamber 3 through the U-shaped pipe 14. Due to the density difference between oil and water, according to the principle of the U-shaped pipe 14... When the floating oil in the coalescing packing zone 5 accumulates to a certain thickness, it will reach the upper part of the oil-water separation chamber 3 through the weir plate 15. When the oil content is relatively low and the degree of emulsification is high, the co-current flow is adopted. The co-current switching valve 19 is opened and the counter-current switching valve 20 is closed. The collected water enters the vertical tank 1 from the lower inlet, and after being ultrasonicated, it enters the coalescing packing zone 5 in the co-current flow. The water flows over the triangular weir plate 15 and enters the upper part of the oil-water separation chamber 3. An oil collection weir 16 is provided at the upper part, and an oil outlet 17 is provided at the bottom of the oil collection weir 16, which is connected to the oil outlet pipe 9.

[0044] The vertical tank 1 is provided with a water outlet 18 in the lower part, and the water outlet pipe 8 is connected to the water outlet 18, located in the lower clarification zone of the oil-water separation chamber.

[0045] The branch inlet pipe 6 controls the dual flow direction through the co-current switching valve 19 or the counter-current switching valve 20. The valve is an electric valve and is activated in conjunction with the online oil content monitoring instrument.

[0046] The branch inlet pipe 6 can be switched to the outlet pipe of the ultrasonic coalescence chamber 2 in the counter-current state via the counter-current outlet switching valve 24.

[0047] The bottom of the vertical tank 1 is provided with a conical sludge collection area 21, and the bottommost part is provided with a sludge discharge port 22, which is connected to a sewage discharge pipe 11.

[0048] The bottom of the ultrasonic coalescence chamber 2 is equipped with a micro aerator 23, which is connected to the micro aeration pipe 7. It is turned on periodically or continuously depending on the water quality. On the one hand, it accelerates the upward speed of oil droplets, and on the other hand, it promotes the self-cleaning of coalescence materials and reduces the pollution and blockage of coalescence packing area 5.

[0049] This invention provides a two-chamber bidirectional ultrasonic coalescing oil-water separation method, comprising the following steps:

[0050] (1) Determination of oil content and properties in water;

[0051] (2) When the oil content in the produced water is high, the flow direction switching device 27 automatically switches to counter-current type. The produced water enters the vertical tank 1 from the upper inlet and flows counter-currently into the coalescing packing zone 5 after ultrasonic demulsification. Since the oil is relatively light, most of the floating oil will remain in the upper part of the coalescing packing zone 5 and will not enter the coalescing material with the water flow, thus avoiding material pollution. After passing through the coalescing material, the emulsified oil and water flow into the upper part of the oil-water separation chamber 3 by gravity through the U-shaped pipe 14. Due to the density difference between oil and water, according to the principle of the U-shaped pipe 14, the floating oil in the coalescing packing zone 5 will accumulate to a certain thickness and reach the upper part of the oil-water separation chamber 3 through the weir plate 15.

[0052] (3) When the oil content in the produced water is relatively low and the degree of emulsification is high, the flow direction switching device 27 automatically switches to a co-current flow. The produced water enters the vertical tank 1 from the lower inlet, is ultrasonically treated, and then flows co-currently into the coalescing packing zone 5. The effluent enters the upper part of the oil-water separation chamber 3 through the weir plate 15. The upper part of the oil-water separation chamber 3 is equipped with an oil collection weir 16, the bottom is equipped with a sludge discharge port 22, and the middle and lower part is equipped with a water outlet 18. The branch inlet pipe 6 controls the dual flow direction through the switching valve. The branch inlet pipe 6 is also the outlet pipe of the ultrasonic coalescing chamber 2 when it is in a co-current state.

[0053] (4) Micro-aeration can be turned on periodically according to water quality conditions to accelerate the upward speed of oil droplets and promote the self-cleaning of aggregated materials;

[0054] (5) The water after ultrasonication and coalescence settles and separates in the oil-water separation chamber 3, and the oil, water and solid phases are separated to achieve the treatment effect.

[0055] Example 1:

[0056] When the oil content is high (e.g., >100mg / L) during online monitoring, the produced water automatically switches to counter-current ultrasonic coalescing oil-water separation via a flow direction switching device. The co-current switching valve 19 is closed, and the counter-current switching valve 20 is opened. The produced water enters the vertical tank 1 from the upper inlet, and after ultrasonic demulsification, flows counter-currently into the coalescing packing zone 5. Due to the lighter weight of the oil, most of the floating oil will remain in the upper part of the coalescing packing zone 5 and will not enter the coalescing material with the water flow, thus avoiding material contamination. After passing through the coalescing material, the emulsified oil and water flow by gravity through the U-shaped pipe 14 into the upper part of the oil-water separation chamber 3. Due to the density difference between oil and water, according to the U-shaped pipe principle, the floating oil in the coalescing packing zone 5 accumulates to a certain thickness and reaches the upper part of the oil-water separation chamber 3 through the weir plate 15. An oil collection weir 16 is provided at the upper part, and an oil outlet 17 is provided at the bottom of the oil collection weir 16, connected to the oil outlet pipe 9. After clarification, the produced water is discharged through the distributor / collector 12 to downstream deep treatment. The bottom of the ultrasonic coalescence chamber 2 is equipped with a micro aerator 23, which is turned on periodically or continuously depending on the water quality. On the one hand, it accelerates the upward speed of oil droplets, and on the other hand, it promotes the self-cleaning of coalescence materials and reduces the pollution and blockage of coalescence packing area 5.

[0057] Example 2:

[0058] When the oil content is slightly low (e.g., ≤100mg / L) during online monitoring, the produced water automatically switches to co-current ultrasonic coalescing oil-water separation via the flow switching device 27. The co-current switching valve 19 is opened, and the counter-current switching valve 20 is closed. The produced water enters the vertical tank 1 from the lower inlet, undergoes ultrasonic treatment, and then flows co-currently into the coalescing packing zone 55. The effluent overflows the weir plate 15 and enters the upper part of the oil-water separation chamber 3. After settling, the oil floats to the surface, where an oil collection weir 16 is located. An oil outlet 17 is located at the bottom of the oil collection weir 16, connected to an oil outlet pipe 9. After clarification, the produced water is discharged through the distributor / collector 12 for downstream deep treatment. A micro-aerator 23 is installed at the bottom of the ultrasonic coalescing chamber 2, which is periodically or continuously activated depending on the water quality. This accelerates the upward movement of oil droplets and promotes the self-cleaning of the coalescing material, reducing contamination and clogging in the coalescing packing zone 5.

[0059] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A two-chamber, bidirectional ultrasonic, coalescence-based oil-water separation method, characterized in that, This method is based on a two-chamber bidirectional ultrasonic coalescing oil-water separation device, which includes: It includes a vertical tank (1), an ultrasonic transducer (4), a branch inlet pipe (6), an ultrasonic generator (13), and a flow direction switching device (27). The vertical tank (1) is divided into two chambers by a weir plate (15), namely an ultrasonic coalescence chamber (2) and an oil-water separation chamber (3). An integrated coalescence packing area (5) is set in the middle of the ultrasonic coalescence chamber (2). Water distributors (12) are installed in the upper and lower parts of the ultrasonic coalescence chamber (2) and the oil-water separation chamber (3). The ultrasonic transducer (4) is installed outside the vertical tank (1) at the same height as the water distributors (12) at the upper and lower inlets. The ultrasonic transducer (4) is connected to the ultrasonic generator (13). The flow direction switching device (27) is used to split the water inlet pipe (6) into two directions, upper and lower, and enter the ultrasonic coalescence chamber (2) of the vertical tank (1) through the water distributor (12). The upper part of the oil-water separation chamber (3) is connected to a U-shaped pipe (14), and an oil collection weir (16) is provided in the upper part of the oil-water separation chamber (3). An oil outlet (17) is provided at the bottom of the oil collection weir (16). The method includes: Determination of oil content and properties in water; When the oil content in the produced water is high, the flow direction switching device (27) automatically switches to counter-current type. The produced water enters the vertical tank (1) from the upper inlet and flows counter-currently into the coalescing packing area (5) after ultrasonic demulsification. Since the oil is relatively light, most of the floating oil stays in the upper part of the coalescing packing area (5) and will not enter the coalescing material with the water flow, thus avoiding material pollution. After passing through the coalescing material, the emulsified oil and water flow into the upper part of the oil-water separation chamber (3) by gravity through the U-shaped pipe (14). Due to the density difference between oil and water, according to the principle of the U-shaped pipe (14), the floating oil in the coalescing packing area (5) accumulates to a set thickness and reaches the upper part of the oil-water separation chamber (3) through the weir plate (15). When the oil content in the produced water is relatively low and the emulsification degree is high, the flow direction switching device (27) automatically switches to a co-current flow. The produced water enters the vertical tank (1) from the lower inlet, and after being ultrasonically treated, it flows into the coalescing packing area (5) in a co-current flow. The water exits through the weir plate (15) and enters the upper part of the oil-water separation chamber (3). The branch inlet pipe (6) controls the dual flow direction through the switching valve. The branch inlet pipe (6) is also the outlet pipe of the ultrasonic coalescing chamber (2) when it is in a co-current flow state. After ultrasonication and coalescence, the water settles and separates in the oil-water separation chamber (3), achieving the desired treatment effect by separating the three phases of oil, water and solid.

2. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 1, characterized in that, The ultrasonic coalescence chamber (2) is equipped with coalescence material, which is made of hydrophilic polyvinyl chloride or stainless steel.

3. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 1, characterized in that, The flow switching device (27) includes an online oil content monitor (25), a co-current switching valve (19), a counter-current switching valve (20), and its control cabinet (26). The online oil content monitor (25) is used to detect the oil content in the water and transmit the data to the control cabinet (26). The control cabinet (26) automatically opens or closes the co-current switching valve (19) or the counter-current switching valve (20). One path is a co-current flow, entering the ultrasonic coalescing chamber (2) from the bottom of the vertical tank (1), and the other path is a counter-current flow, entering the ultrasonic coalescing chamber (2) from the top of the vertical tank (1).

4. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 3, characterized in that, Both the co-current switching valve (19) and the counter-current switching valve (20) are electric valves.

5. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 3, characterized in that, The branch inlet pipe (6) can be switched to the ultrasonic coalescence chamber outlet pipe in the counter-current state through the counter-current outlet switching valve (24).

6. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 1, characterized in that, The vertical tank (1) has an outlet (18) in the lower part.

7. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 1, characterized in that, The bottom of the vertical tank (1) is provided with a conical mud collection area (21) and the bottommost part is provided with a mud discharge port (22).

8. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 7, characterized in that, The sludge discharge port (22) is connected to the sewage pipe (11).

9. The two-chamber bidirectional ultrasonic coalescence oil-water separation method according to claim 1, characterized in that, The bottom of the ultrasonic coalescence chamber (2) is equipped with a micro aerator (23), which is connected to the micro aeration pipe (7).

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