Oil removal device for oilfield oily wastewater treatment and wastewater treatment method

Abstract

The present application relates to the field of oilfield oily wastewater treatment, and particularly relates to an oil removal device for oilfield oily wastewater treatment and a wastewater treatment method. The device comprises a treatment tank, a chain conveying mechanism and an oil scraping assembly. The treatment tank is divided into a pretreatment zone, an oil collection zone, a gas flotation zone and a dosing zone. The gas flotation zone is provided with an aeration assembly at the bottom. The side of the gas flotation zone close to the dosing zone is the starting position, and the side close to the oil collection zone is the end position. The chain conveying mechanism is located at the starting position and the end position of the gas flotation zone respectively. The oil scraping assembly comprises a support structure and a scraper. The support structure is provided with a linear actuator in transmission connection with the scraper. The device integrates the functions of pretreatment, dosing, gas flotation and oil collection. The scraper is combined with a flexible rubber strip to prevent oil leakage. A liquid level sensor detects the oil layer thickness in real time and adjusts the liquid depth of the scraper through the linear actuator. Buffer springs absorb the propulsion impact to realize efficient and stable oil scraping.

Description

Technical Field

[0001] This invention relates to the field of oilfield oily wastewater treatment, specifically to an oil removal device and a wastewater treatment method for oilfield oily wastewater. Background Technology

[0002] In the treatment of oily wastewater in oil fields, air flotation is a commonly used oil removal process. It involves introducing microbubbles into the wastewater to cause oil droplets to adhere and float to form a floating oil layer. Then, a surface scraper is used to scrape the floating oil to an oil collection tank to achieve oil-water separation.

[0003] However, existing oil skimming devices mostly use rigid flat scrapers, which have obvious technical defects: On the one hand, gaps inevitably remain between the scraper and the side wall of the tank due to mechanical installation tolerances or structural limitations, resulting in the inability to effectively remove floating oil in the edge area of ​​the tank wall, forming dead corners for oil accumulation. On the other hand, the scraper is usually installed at a fixed height, and its immersion depth below the liquid surface cannot be dynamically adjusted according to the thickness of the floating oil layer and changes in liquid level during actual operation. This makes it difficult to effectively capture some fine oil droplets or oil phases containing air bubbles suspended near the surface, thereby reducing the overall oil removal efficiency and affecting the quality of the effluent.

[0004] Therefore, there is a current need for oil removal devices to treat oily wastewater from oil fields. These devices can effectively solve the problems of dead zones and insufficient adjustment capabilities in the actual operation of traditional scraper-type oil removal equipment, improve the overall oil removal efficiency, and ensure that the effluent water quality meets the standards. Summary of the Invention

[0005] To address the problems existing in the current technology, an oil removal device for treating oily wastewater from oil fields is provided. By integrating pretreatment, chemical dosing, flotation and oil collection functions, combined with a scraper with flexible rubber strips to adhere to the pool wall to prevent oil leakage, a liquid level sensor to detect the oil layer thickness in real time and link with a linear actuator to adjust the depth of the scraper into the liquid, and a buffer spring to absorb the propulsion impact, the device achieves efficient and stable removal of floating oil.

[0006] To address the problems of existing technologies, this invention provides an oil removal device for treating oily wastewater from oilfields, comprising a treatment tank, a chain conveyor mechanism, and an oil skimming assembly. The treatment tank is divided horizontally into a pretreatment zone, an oil collection zone, an air flotation zone, and a chemical dosing zone. The top of the pretreatment zone is equipped with a filter bag to intercept large particulate impurities in the wastewater. The bottom of the air flotation zone is equipped with an aeration assembly to generate microbubbles to promote oil-water separation. A conveying pipeline connects the pretreatment zone and the air flotation zone. A chemical dosing port connects the chemical dosing zone and the air flotation zone. The side of the air flotation zone closest to the chemical dosing zone is the starting position, and the side closest to the oil collection zone is the ending position. The chain conveyor mechanism is horizontally mounted on the top of the treatment tank, with its two ends located at the starting and ending positions of the air flotation zone, respectively, for circulating the oil skimming assembly. The oil skimming assembly includes a support structure, which is drivenly connected to the chain conveyor mechanism, and a scraper, which is mounted on the support structure and can move vertically to adjust the liquid immersion depth. A linear drive, drivenly connected to the scraper, is mounted on the support structure.

[0007] Preferably, the two ends of the scraper extend toward the side walls of the treatment tank, and the oil-facing edge of the scraper is provided with a flexible rubber strip, which is in close contact with the inner side wall of the treatment tank to prevent floating oil from leaking from the side.

[0008] Preferably, the support structure includes a support plate fixedly connected to the chain conveying mechanism and a buffer plate rotatably connected to the front side of the support plate. A buffer spring is provided between the buffer plate and the support plate to absorb the impact load on the scraper during the advancement process.

[0009] Preferably, the upper part of the support plate is provided with a horizontally extending plate, and a liquid level sensor with its output end extending vertically downward is installed on the horizontal plate for real-time detection of the thickness of the floating oil layer. The liquid level sensor is electrically connected to the linear actuator.

[0010] Preferably, the scraper is slidably disposed on the surface of the buffer plate, and the linear actuator is mounted on the buffer plate. The linear actuator includes an electric screw threadedly connected to the scraper.

[0011] Preferably, the buffer plate has a fixed plate for mounting the electric screw, and the scraper has a movable plate through which the electric screw passes and is threadedly engaged with it. The fixed plate and the movable plate are parallel to each other and are provided with an anti-detachment structure.

[0012] Preferably, the anti-detachment structure includes a guide rod and a compression spring. One end of the guide rod is fixedly connected to the moving plate, and the other end extends vertically through the fixed plate and slides with it. Both ends of the compression spring are fixedly connected to the extended end of the guide rod and the upper surface of the fixed plate, respectively.

[0013] Preferably, there are two oil scraping components, which are respectively installed in the upper and lower half of the chain conveyor mechanism. When one oil scraping component is located at the beginning position of the air flotation zone, the other oil scraping component is simultaneously located at the end position.

[0014] Preferably, the flotation zone is equipped with a stirring component to promote uniform mixing of the reagent and wastewater to accelerate the upward movement of oil droplets.

[0015] The present invention also provides a wastewater treatment method for the above-mentioned oil removal device, comprising the following steps: S1. Introduce oily wastewater into the pretreatment zone and remove large particulate impurities through a filter bag; S2. The pretreated wastewater is sent to the flotation zone through the conveying pipeline, and the chemical dosing zone is simultaneously added to mix with the bottom aeration components and flotate. S3. After the floating oil rises and gathers on the liquid surface, the oil scraping component located at the starting position moves along the surface of the air flotation zone towards the ending position, continuously scraping the floating oil to the oil collection zone. S4. The oil scraping component that has completed the oil scraping operation moves to the end position, while another oil scraping component is already in the starting position and ready to go, realizing the dual-station alternating cycle operation.

[0016] The advantages of this application compared to the prior art are: 1. This invention integrates pretreatment, chemical dosing, flotation and oil collection functions in the treatment tank, and adopts dual oil scraping components operating alternately and full-width scrapers with flexible rubber strips to achieve efficient treatment of oily wastewater. When one oil scraping component is at the beginning of the flotation zone, the other oil scraping component is simultaneously at the end, improving the continuity of treatment.

[0017] During the oil removal process, the flexible rubber strip dynamically seals against the pool wall to effectively prevent side leakage of floating oil. The linear actuator adjusts the scraper depth in real time according to the oil layer thickness, which effectively captures some of the fine oil droplets or oil phases containing air bubbles that are suspended near the surface. Combined with the gate guide and spray cleaning, this improves the overall oil removal efficiency and avoids secondary pollution.

[0018] 2. The present invention effectively absorbs the impact load caused by liquid surface fluctuations or floating oil resistance during the scraper's advancement by setting a flexible buffer structure consisting of a support plate, a buffer plate and a buffer spring in the oil scraper assembly, thus avoiding rigid damage and operation interruption.

[0019] Meanwhile, a horizontal plate and a vertically downward liquid level sensor are integrated on the upper part of the support plate. When the oil layer thickens or thins due to changes in operating conditions, such as fluctuations in the oil content of the influent or changes in the flotation efficiency, the liquid level sensor immediately transmits the detection signal to the control system. The control system then sends a command to the linear actuator to dynamically adjust the depth of the scraper into the liquid, thus realizing the smooth operation and depth adaptive control of the oil scraping process, improving the oil removal efficiency and automation level.

[0020] 3. This invention achieves a multi-effect coupling effect by synergistically setting up a dosing port, a stirring component and a bottom aeration component in the flotation zone, thereby enabling rapid and uniform dispersion of the agent, efficient demulsification and coagulation of tiny oil droplets and full adhesion of microbubbles.

[0021] The stirring component promotes thorough mixing of the reagent and wastewater and enhances the collision efficiency of oil droplets and bubbles without disrupting the formed oil clumps, thus shortening the oil-water separation time. Combined with the micron-sized bubbles released by the aeration component, the coagulated oil clumps quickly float to the surface, forming a continuous and stable floating oil layer. This provides favorable conditions for subsequent efficient oil scraping, significantly improving the overall oil removal efficiency and treatment stability. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural schematic diagram of the oil removal device for treating oily wastewater from oilfields according to the present invention.

[0023] Figure 2 This is a three-dimensional structural cross-sectional view of the oil removal device for treating oily wastewater from oilfields according to the present invention.

[0024] Figure 3 This is a plan sectional view of the oil removal device for treating oily wastewater from oilfields according to the present invention.

[0025] Figure 4 This is the invention Figure 2 Enlarged diagram of point A.

[0026] Figure 5 This is the invention Figure 3 Enlarged diagram of point B.

[0027] Figure 6 This is a three-dimensional structural diagram of the chain conveyor mechanism and oil scraping assembly of the oil removal device for treating oily wastewater in oilfields according to the present invention, viewed from a first perspective.

[0028] Figure 7 This is a three-dimensional structural diagram of the chain conveyor mechanism and oil scraping assembly of the oil removal device for treating oily wastewater in oilfields according to the present invention, viewed from a second perspective.

[0029] Figure 8 This is a partial three-dimensional structural diagram of the chain conveyor mechanism and the oil scraping assembly of the oil removal device for treating oily wastewater in oilfields according to the present invention.

[0030] Figure 9 This is a partial plan view of the chain conveyor mechanism and the oil skimming assembly of the oil removal device for treating oily wastewater in oilfields according to the present invention.

[0031] Figure 10 This is a three-dimensional structural schematic diagram of the oil scraping component of the oil removal device for treating oily wastewater in oilfields according to the present invention, viewed from a first perspective.

[0032] Figure 11 This is a three-dimensional structural schematic diagram of the oil scraping component of the oil removal device for treating oily wastewater in oilfields according to the present invention, viewed from a second perspective.

[0033] Figure 12 This is an exploded three-dimensional structural diagram of the oil scraping component of the oil removal device for treating oily wastewater in oilfields according to the present invention.

[0034] The diagram is labeled as follows: 1. Treatment tank; 11. Pretreatment zone; 111. Filter bag; 12. Oil collection zone; 121. Gate; 122. Slope; 13. Air flotation zone; 131. Aeration assembly; 132. Conveying pipeline; 14. Chemical dosing zone; 141. Chemical dosing port; 2. Chain conveyor mechanism; 3. Oil scraper assembly; 31. Support structure; 311. Support plate; 3111. Horizontal plate; 3112. Liquid level sensor; 312. Buffer plate; 3121. Buffer spring; 32. Scraper; 321. Flexible rubber strip; 33. Linear actuator; 331. Electric screw; 332. Fixed plate; 333. Moving plate; 34. Anti-detachment structure; 341. Guide rod; 342. Compression spring; 4. Cleaning assembly; 41. Cleaning nozzle assembly; 42. Receiving tank; 5. Agitator assembly. Detailed Implementation

[0035] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0036] See Figures 1 to 10 As shown, the oil removal device for treating oily wastewater from an oilfield includes a treatment tank 1, a chain conveyor mechanism 2, and an oil skimmer assembly 3. The treatment tank 1 is divided horizontally into a pretreatment zone 11, an oil collection zone 12, an air flotation zone 13, and a chemical dosing zone 14. The pretreatment zone 11 has a filter bag 111 at its top to intercept large particulate impurities in the wastewater. The air flotation zone 13 has an aeration assembly 131 at its bottom to generate microbubbles to promote oil-water separation. A conveying pipeline 132 connects the pretreatment zone 11 and the air flotation zone 13. A chemical dosing port 141 connects the chemical dosing zone 14 and the air flotation zone 13. The side of the air flotation zone 13 closest to the chemical dosing zone 14 is the starting position, and the side closest to the oil collection zone 12 is the ending position. The chain conveyor mechanism 2 is horizontally mounted on top of the treatment tank 1, with its two ends located at the starting and ending positions of the air flotation zone 13, respectively, for circulating the oil skimmer assembly 3. The oil skimmer assembly 3 includes: Support structure 31 is connected to chain conveyor mechanism 2 via transmission; The scraper 32 is mounted on the support structure 31 and can move vertically to adjust the liquid immersion depth; The support structure 31 is equipped with a linear driver 33 that is connected to the scraper 32 for transmission.

[0037] At the entrance of the oil collection area 12, there is a gate 121 that can be moved vertically downward. The top of the gate 121 is provided with a slope 122. When the gate 121 moves downward, the oil residue slides into the oil collection area 12 along the slope.

[0038] The chain conveyor 2 is equipped with a cleaning component 4 above the end position. The cleaning component 4 includes an upper cleaning nozzle group 41 and a lower receiving groove 42, which is used to automatically rinse the returning oil scraping component 3.

[0039] Treatment process: Oily wastewater first enters the pretreatment zone 11 at the front end of treatment tank 1. When the wastewater flows in, it first passes through the filter bag 111, where large particulate impurities are intercepted and retained in the bag, thus completing the initial purification. Subsequently, the pretreated wastewater does not flow directly to the adjacent area, but is guided to the flotation zone 13 located in treatment tank 1 through the conveying pipeline 132. At the same time, the chemical addition zone 14 of treatment tank 1 injects demulsifier or flocculant into the flotation zone 13 through the chemical addition port 141. After the chemical enters the flotation zone 13, it mixes with the wastewater, causing the tiny oil droplets to aggregate into larger oil clumps. At this time, the aeration components 131 arranged at the bottom of the flotation zone 13 start to work, continuously releasing a large number of micron-sized bubbles. As the bubbles rise, they adhere to the surface of the oil clumps, reducing their density and causing them to float rapidly. Finally, a continuous and stable floating oil layer is formed on the liquid surface of the flotation zone 13.

[0040] Above the flotation zone 13, the chain conveyor 2 spans the entire area. Its drive ends are positioned at the starting position on the side of the flotation zone 13 near the chemical addition zone 14 and the ending position on the side near the oil collection zone 12. The chain continuously circulates, driving the oil scraping assembly 3 installed on it to move along the liquid surface of the flotation zone 13. The oil scraping assembly 3 moves from the starting position to the ending position along with the chain. The scraper 32 is driven by the linear actuator 33 and can automatically adjust the liquid depth according to the real-time oil layer thickness, efficiently pushing the floating oil forward, so that some of the fine oil droplets or oil phases containing air bubbles suspended near the surface are effectively captured, thereby improving the overall oil removal efficiency.

[0041] When the scraper 32 carries the floating oil to the junction of the flotation zone 13 and the oil collection zone 12, the gate 121 moves vertically downward to open the channel, allowing the accumulated oil residue to slide down the slope 122 into the oil collection zone 12 for collection, thus avoiding the accumulation of oil residue or backflow that pollutes the treated water.

[0042] After completing the oil scraping task, the oil scraping assembly 3 continues to move upward with the chain and enters the area directly above the end position. At this position, the oil scraping assembly 3 passes through the upper cleaning nozzle group 41 and the lower receiving tank 42. The cleaning nozzle group 41 is activated and sprays high-pressure cleaning water or cleaning fluid downward to thoroughly wash the scraper 32, the support structure 31 and the residual oil stains attached to the surrounding area. The wastewater generated by rinsing is collected and discharged by the lower receiving tank 42 to prevent secondary pollution.

[0043] After cleaning, the oil scraper assembly 3 enters the return section with the chain and returns to the starting position to wait.

[0044] See Figures 2 to 12 As shown, the two ends of the scraper 32 extend toward the two side walls of the treatment tank 1 respectively. The oil-facing edge of the scraper 32 is provided with a flexible rubber strip 321. The flexible rubber strip 321 is tightly attached to the inner side wall of the treatment tank 1 to prevent floating oil from leaking from the side.

[0045] During the oil skimming operation, the scraper 32 spans across the liquid surface of the flotation zone 13 and moves from the starting position to the ending position with the chain conveyor 2. Both ends of the scraper 32 extend towards the left and right side walls of the treatment tank 1 respectively, ensuring that the effective width of the entire flotation zone 13 is covered.

[0046] On the oil-facing edge of the scraper 32, i.e. the side facing the direction of the floating oil, a flexible rubber strip 321 is installed, which is made of an oil-resistant, wear-resistant and elastic material. When the scraper 32 is pushed forward, the flexible rubber strip 321, under the action of its own elasticity and the thrust of the scraper 32, always maintains a tight fit with the inner wall of the treatment tank 1, forming a dynamic sealing interface. This fit effectively seals the gap between the scraper 32 and the tank wall, preventing the floating oil from flowing around or leaking from the two sides during the scraping process, thereby ensuring that the floating oil is pushed completely and centrally to the oil collection area 12, improving the oil removal efficiency and avoiding oil residue or secondary diffusion.

[0047] See Figures 4 to 12 As shown, the support structure 31 includes a support plate 311 fixedly connected to the chain conveying mechanism 2 and a buffer plate 312 rotatably connected to the front side of the support plate 311. A buffer spring 3121 is provided between the buffer plate 312 and the support plate 311 to absorb the impact load on the scraper 32 during the advancement process.

[0048] During the operation of the oil scraping assembly 3, the support structure 31, as the intermediate bearing unit connecting the chain and the scraper 32, is first firmly fixed to the chain conveying mechanism 2 through its support plate 311 and moves synchronously with the chain. The front side of the support plate 311 is rotatably connected to the buffer plate 312 through a rotating shaft, and the scraper 32 is installed on the buffer plate 312.

[0049] When the scraper 32 encounters obstacles such as liquid surface fluctuations, floating oil accumulation resistance, or minor unevenness of the pool wall during its advancement, it will generate instantaneous impact loads. At this time, the buffer spring 3121 located between the buffer plate 312 and the support plate 311 is compressed by force, and absorbs and mitigates the impact energy through elastic deformation. This allows the scraper 32 to flexibly adapt to changes in working conditions, avoiding structural damage, chain jumping, or interruption of oil scraping caused by rigid collisions. This buffering mechanism not only improves the stability of the oil scraping process, but also effectively protects the chain drive and the scraper 32 body, ensuring long-term stable operation.

[0050] See Figure 4 , Figure 5 and Figures 8 to 12 As shown, the upper part of the support plate 311 is provided with a horizontally extending plate 3111, and a liquid level sensor 3112 with its output end extending vertically downward is installed on the horizontal plate 3111 for real-time detection of the thickness of the floating oil layer. The liquid level sensor 3112 is electrically connected to the linear actuator 33.

[0051] During the operation of the oil skimmer assembly 3, the horizontal plate 3111 installed on the upper part of the support plate 311 extends laterally to the liquid surface above the air flotation zone 13. The liquid level sensor 3112 is fixedly installed on its lower surface, with the detection end pointing vertically downward to the liquid surface. As the oil skimmer assembly 3 moves, the liquid level sensor 3112 continuously performs non-contact scanning on the surface of the floating oil layer below to obtain oil layer thickness or liquid level height data in real time.

[0052] When the oil layer thickens or thins due to changes in operating conditions, such as fluctuations in the oil content of the influent or changes in the flotation efficiency, the level sensor 3112 immediately transmits the detection signal to the control system. Based on this, the control system sends a command to the linear actuator 33 to drive the scraper 32 to move up and down along the buffer plate 312, dynamically adjusting its immersion depth to ensure that the scraper 32 is always in the optimal position to adhere to the oil surface for efficient scraping. Through the electrical connection and collaborative work between the level sensor 3112 and the linear actuator 33, intelligent adaptive adjustment of the oil scraping depth is achieved, improving the stability and automation level of oil removal.

[0053] See Figures 8 to 12 As shown, the scraper 32 is slidably disposed on the surface of the buffer plate 312, and the linear actuator 33 is mounted on the buffer plate 312. The linear actuator 33 includes two electric screws 331 symmetrically disposed at both ends of the buffer plate 312 and threadedly connected to the scraper 32.

[0054] During the operation of the oil scraping assembly 3, the scraper 32 is slidably mounted on the front surface of the buffer plate 312 and can move up and down along its vertical direction. To achieve this action, the linear actuator 33 integrated on the buffer plate 312 is composed of an electric screw 331 and forms a threaded connection with the scraper 32.

[0055] When the control system issues an adjustment command, the electric screw 331 rotates synchronously forward or reverse, and converts the rotational motion into linear motion of the scraper 32 along the surface of the buffer plate 312 through the screw drive, thereby accurately and smoothly adjusting the depth of the scraper 32 relative to the liquid surface, ensuring that the scraper 32 always efficiently adheres to the surface of the floating oil layer for operation.

[0056] See Figures 8 to 12As shown, the buffer plate 312 has a fixed plate 332 for mounting the electric screw 331, and the scraper 32 has a movable plate 333 through which the electric screw 331 passes and is threadedly engaged with it. The fixed plate 332 and the movable plate 333 are parallel to each other and are provided with an anti-detachment structure 34.

[0057] During the lifting and lowering adjustment of the scraper 32, when the electric screw 331 rotates, the moving plate 333 moves along the screw axis under the action of the screw thread, thereby driving the entire scraper 32 to slide up and down relative to the buffer plate 312, so as to realize the adjustment of the liquid immersion depth.

[0058] To ensure safe and reliable operation, the fixed plate 332 and the moving plate 333 always maintain a parallel relative posture, and an anti-detachment structure 34 is set between them to limit the maximum displacement of the moving plate 333 within its stroke range, prevent the scraper 32 from detaching from the buffer plate 312 track, ensure the stability of the scraper 32 movement, and make the entire lifting adjustment maintain high reliability in long-term continuous operation.

[0059] See Figures 8 to 12 As shown, the anti-detachment structure 34 includes a guide rod 341 and a compression spring 342. One end of the guide rod 341 is fixedly connected to the moving plate 333, and the other end extends vertically through the fixed plate 332 and slides with it. The two ends of the compression spring 342 are fixedly connected to the extension end of the guide rod 341 and the upper surface of the fixed plate 332, respectively.

[0060] During the lifting and lowering of the scraper 32, the anti-detachment structure 34 works in conjunction with the guide rod 341 and the compression spring 342 to ensure safe and stable operation. One end of the guide rod 341 is firmly connected to the moving plate 333, and the other end passes vertically upward through the guide hole on the fixed plate 332 and maintains a sliding fit with the hole, so that the moving plate 333 is always constrained in the vertical track by the guide rod 341 when it is lifted and lowered with the electric screw 331, preventing deflection or shaking.

[0061] Meanwhile, when the scraper 32 moves downward, the moving plate 333 drives the guide rod 341 to move downward synchronously, and the compression spring 342 is compressed. When the scraper 32 moves upward, the compression spring 342 is reset by its elastic force. This not only realizes the dual functions of guiding and limiting, but also improves the stability and impact resistance of the scraper 32.

[0062] See Figures 1 to 3 As shown, there are two oil scraping components 3, which are respectively installed in the upper half and lower half of the chain conveyor mechanism 2. When one of the oil scraping components 3 is located at the starting position of the air flotation zone 13, the other oil scraping component 3 is simultaneously located at the ending position.

[0063] During operation, the chain conveyor 2 operates in a closed loop. Its lower half spans above the liquid surface of the flotation zone 13 to perform oil skimming, while its upper half is located above the treatment tank 1 as the return path. Two oil skimming components 3 are fixedly installed on the upper and lower halves of the chain, respectively, with a phase difference of approximately half a cycle.

[0064] When the chain drive is running, the oil scraping assembly 3 in the lower half moves from the starting position toward the oil collection area 12 to perform oil scraping. At the same time, another oil scraping assembly 3 that has already completed oil scraping and entered the return stroke gradually moves with the chain to the starting position. Conversely, when the former completes oil scraping and reaches the end position, the latter has returned to the starting position to stand by, thereby ensuring that the oil in the flotation zone 13 is continuously and efficiently removed, improving processing efficiency.

[0065] See Figure 2 and Figure 3 As shown, the air flotation zone 13 is equipped with a stirring component 5, which is used to promote uniform mixing of the reagent and wastewater to accelerate the floating of oil droplets.

[0066] After the oily wastewater enters the flotation zone 13, the dosing zone 14 injects demulsifier or flocculant into it through the dosing port 141. At this time, the stirring component 5 installed in the flotation zone 13 is immediately started to gently and fully stir the wastewater in the tank. This stirring process promotes the rapid diffusion of the agent and uniform mixing with the wastewater, so that the tiny oil droplets can effectively contact the agent and undergo demulsification and coagulation reactions to form oil clumps with larger particle size and easier to attach bubbles.

[0067] Meanwhile, the moderate turbulence generated by stirring helps microbubbles and oil droplets to fully collide and combine, avoiding a decrease in separation efficiency caused by excessively high local reagent concentrations or uneven mixing. The entire stirring process shortens the time required for oil-water separation and accelerates the speed at which oil droplets rise to the liquid surface, while ensuring that the formed oil clumps are not broken, thus creating favorable conditions for the subsequent efficient collection of floating oil by the oil skimming component 3.

[0068] A wastewater treatment method for oily wastewater from oilfields, applied to the oil removal device described above, includes the following steps: S1. Oily wastewater is introduced into the pretreatment zone 11 and large particulate impurities are removed through the filter bag 111. S2. The pretreated wastewater is sent to the flotation zone 13 via the conveying pipeline 132. At the same time, the dosing zone 14 adds the reagents and starts the stirring component 5 and the bottom aeration component 131 to mix and flot. S3. After the floating oil rises and gathers on the liquid surface, the oil scraping component 3 located at the starting position moves along the surface of the air flotation zone 13 toward the ending position, continuously scraping the floating oil to the oil collection zone 12. S4. The oil scraping component 3, which has completed the oil scraping operation, moves to the end position, while another oil scraping component 3 is already in the starting position and ready to be used, realizing the dual-station alternating cycle operation.

[0069] This invention improves the continuity and stability of oily wastewater treatment by integrating pretreatment, chemical dosing, flotation and oil collection functions in the treatment tank 1, and constructing a high-efficiency oil removal system consisting of alternating operation of dual oil scraping components 3, full-width scraper 32 with flexible rubber strip 321, intelligent depth adjustment and automatic cleaning.

[0070] The flexible rubber strip 321 forms a dynamic seal with the pool wall, effectively preventing side leakage of floating oil. The linear actuator 33, combined with the liquid level sensor 3112, senses the oil layer thickness in real time and adaptively adjusts the depth of the scraper 32 to accurately capture surface and near-surface micro-oil droplets. The buffer spring 3121 in the support structure 31 absorbs operational shocks, ensuring stable operation.

[0071] Meanwhile, within the flotation zone 13, the dosing, stirring, and aeration components 5 and 131 work synergistically to accelerate reagent mixing, oil droplet coagulation, and bubble adhesion without disrupting the oil clumps, rapidly forming a stable floating oil layer. This achieves highly efficient and automated operation throughout the entire process, from impurity removal and oil-water separation to floating oil collection and self-cleaning, significantly improving oil removal efficiency and preventing secondary pollution.

[0072] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An oil removal device for treating oily wastewater from oilfields, characterized in that, It includes a treatment tank (1), a chain conveyor mechanism (2), and an oil skimmer assembly (3); The treatment tank (1) is divided into a pretreatment zone (11), an oil collection zone (12), an air flotation zone (13), and a chemical dosing zone (14) in the transverse direction. The pretreatment zone (11) is equipped with a filter bag (111) at the top to intercept large particulate impurities in the wastewater; The bottom of the air flotation zone (13) is provided with an aeration component (131) to generate microbubbles to promote oil-water separation; A conveying pipeline (132) connects the pretreatment zone (11) and the air flotation zone (13). A dosing port (141) is provided between the dosing zone (14) and the flotation zone (13). The side of the air flotation zone (13) closest to the dosing zone (14) is the starting position, and the side closest to the oil collection zone (12) is the ending position; The chain conveyor (2) is horizontally mounted on the top of the treatment tank (1), with its two ends located at the beginning and end of the air flotation zone (13) respectively, for circulating conveying of the oil scraping assembly (3). The oil scraping assembly (3) includes: The support structure (31) is connected to the chain conveyor mechanism (2) for transmission. A scraper (32) is provided on the support structure (31) and can move vertically to adjust the liquid depth. The support structure (31) is provided with a linear driver (33) that is connected to the scraper (32) for transmission.

2. The oil removal device for treating oily wastewater from oilfields according to claim 1, characterized in that, The scraper (32) extends towards the two side walls of the treatment tank (1) at both ends. The scraper (32) is provided with a flexible rubber strip (321) on the oil-facing edge. The flexible rubber strip (321) is tightly attached to the inner side wall of the treatment tank (1) to prevent floating oil from leaking from the side.

3. The oil removal device for treating oily wastewater from oilfields according to claim 2, characterized in that, The support structure (31) includes a support plate (311) fixedly connected to the chain conveying mechanism (2) and a buffer plate (312) rotatably connected to the front side of the support plate (311). A buffer spring (3121) is provided between the buffer plate (312) and the support plate (311) to absorb the impact load on the scraper (32) during the advancement process.

4. The oil removal device for treating oily wastewater from oilfields according to claim 3, characterized in that, The support plate (311) has a horizontally extending horizontal plate (3111) on its upper part. A liquid level sensor (3112) with its output end extending vertically downward is installed on the horizontal plate (3111) for real-time detection of the thickness of the floating oil layer. The liquid level sensor (3112) is electrically connected to the linear driver (33).

5. The oil removal device for treating oily wastewater from oilfields according to claim 4, characterized in that, The scraper (32) is slidably disposed on the surface of the buffer plate (312), and the linear actuator (33) is mounted on the buffer plate (312). The linear actuator (33) includes an electric screw (331) that is threadedly connected to the scraper (32).

6. The oil removal device for treating oily wastewater from oilfields according to claim 5, characterized in that, The buffer plate (312) has a fixed plate (332) for mounting the electric screw (331), and the scraper (32) has a movable plate (333) through which the electric screw (331) passes and is threadedly engaged with it. The fixed plate (332) and the movable plate (333) are parallel to each other and are provided with an anti-detachment structure (34).

7. The oil removal device for treating oily wastewater from oilfields according to claim 6, characterized in that, The anti-detachment structure (34) includes a guide rod (341) and a compression spring (342). One end of the guide rod (341) is fixedly connected to the moving plate (333), and the other end extends vertically through the fixed plate (332) and slides with it. The two ends of the compression spring (342) are fixedly connected to the extension end of the guide rod (341) and the upper surface of the fixed plate (332), respectively.

8. The oil removal device for treating oily wastewater from oilfields according to claim 1, characterized in that, Two oil scraping components (3) are provided, which are respectively installed in the upper half and lower half of the chain conveyor (2). When one of the oil scraping components (3) is located at the starting position of the air flotation zone (13), the other oil scraping component (3) is simultaneously located at the ending position.

9. The oil removal device for treating oily wastewater from oilfields according to claim 1, characterized in that, The air flotation zone (13) is equipped with a stirring component (5) to promote uniform mixing of the reagent and wastewater to accelerate the upward movement of oil droplets.

10. A wastewater treatment method for an oil removal device for treating oily wastewater from oilfields as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. The oily wastewater is introduced into the pretreatment zone (11) and large particulate impurities are removed through the filter bag (111); S2. The pretreated wastewater is sent to the flotation zone (13) via the conveying pipeline (132), and the chemical dosing zone (14) adds the chemical agent at the same time to mix and flotate with the bottom aeration component (131). S3. After the floating oil rises and gathers on the liquid surface, the oil scraping component (3) located at the starting position moves along the surface of the air flotation zone (13) towards the end position, and continuously scrapes the floating oil to the oil collection zone (12). S4. The oil scraping component (3) that has completed the oil scraping operation moves to the end position, while another oil scraping component (3) is already in the starting position and ready to go, realizing the dual-station alternating cycle operation.

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