Oilfield sewage demulsification enhanced treatment device and process

Abstract

The present application relates to a kind of oilfield sewage demulsification enhanced treatment device and process, belong to oilfield sewage treatment technical field.The device is sequentially built in the multi-stage vertical tank from bottom to top, and the mixing zone, reaction zone, laminar flow aggregation zone and gravity separation zone are sequentially built.The high-energy shear demulsification with flow self-adaption is realized by adopting cyclone mechanism with elastic sheet;In buffer cavity, copolymerization gas-containing alum flower is formed by combining high molecular flocculants with micro-nano bubbles, and the growth time is controlled through spiral channel;Through the separation plate, the flow state is forced to reduce dimension into laminar flow, and the pure oil is quickly aggregated and enlarged by using lipophilic coalescence filler;Constant liquid level is locked by using inverted U-shaped clean water pipe at the top, the escaped gas is intercepted to form gas pressure thrust through micro-pressure safety valve, and oil is forced to press into oil outlet pipe, which solves the problem of wall hanging and oil discharge blockage caused by poor oil flowability.

Description

Technical Field

[0001] This invention relates to an enhanced demulsification treatment device and process for oilfield wastewater, belonging to the field of oilfield wastewater treatment technology. Background Technology

[0002] In the later stages of oilfield development, a large amount of high-water-cut produced wastewater is generated, which must be demulsified and separated before reinjection or discharge. Traditional methods for demulsifying and treating oilfield wastewater typically involve a three-step process: First, chemical mixing, where demulsifiers are added to pipelines or mixers with a very short residence time, resulting in uneven mixing; second, reactive demulsification, where the wastewater is held in a large reaction tank, but the flow field inside the tank is chaotic, the probability of oil droplets meeting and coalescing is random, and the process is inefficient; third, gravity settling or flotation, where the wastewater is left to stand for a long time in a large tank for separation.

[0003] The pain point of existing technologies lies in the fact that this "three-step" process is physically disconnected, failing to create an optimal "temporal microenvironment" for the demulsifier to function (adsorption → membrane rupture → coalescence → separation). High-performance demulsifiers require extremely high shear forces in the initial stage to seize the interface, while an extremely stable laminar flow environment is needed during the coalescence period, which traditional equipment struggles to achieve simultaneously. At the same time, traditional large settling tanks occupy a large area, are highly susceptible to fluctuations in influent water, and often experience problems such as top oil accumulation and stagnation, difficulty in oil drainage, and even pipeline blockage when dealing with high-viscosity "dead oil". Summary of the Invention

[0004] The technical problem to be solved by the present invention is: The present invention provides a single vertical oilfield wastewater demulsification enhancement treatment device and process, which creates four sequential functional zones in a compact tank by different spatial structure designs within the tank.

[0005] The oilfield wastewater demulsification and enhanced treatment device of the present invention includes a tank, wherein the tank is constructed from bottom to top as a mixing zone, a reaction zone, a laminar flow accumulation zone and a gravity separation zone; The mixing zone includes a sedimentation chamber located at the bottom of the tank and an inlet riser arranged within the sedimentation chamber. A swirling mechanism is connected to the upper end of the inlet riser. The swirling mechanism includes an outer swirling cylinder and an inner swirling tube arranged coaxially inside it. Swirling grooves are evenly distributed around the circumference of the inner swirling tube. An inclined guide plate is provided at one side of the groove to form a tangential inlet, and an elastic plate is provided at the other side of the groove to dynamically adjust the water flow rate entering the outer swirling cylinder by deformation under water pressure. A demulsifier tube arranged coaxially for high-pressure injection of demulsifier is inserted into the upper end of the inner swirling tube. The reaction zone includes a flow stabilizer plate arranged inside the tank and above the outer vortex tube. A reaction mechanism that can be pulled out from the top is placed above the flow stabilizer plate. The reaction mechanism includes an outer shell, a spiral channel inside the outer shell, and a buffer chamber located below. A polymer flocculant tube with downward water outlet holes is arranged in a ring inside the buffer chamber. A micro-nano bubble injection tube with nozzles is also provided at the top of the buffer chamber. The laminar flow accumulation zone includes an inverted conical sedimentation shell with an inlet located above the outer shell. A partition plate is installed at the upper end of the sedimentation shell, and oleophilic polymeric filler is densely filled above the partition plate. A barrier plate is installed at the upper end of the oleophilic polymeric filler. A receiving tube extending downward through the outer shell is connected to the lower end of the sedimentation shell. The gravity separation zone is located above the baffle plate, and a downward-extending clear water chamber is provided near the inner wall of the tank. An inverted U-shaped clear water pipe extending outward is connected to the clear water chamber to lock the internal oil-water interface. An inverted conical primary collection tank is provided above the gravity separation zone. A secondary collection tank is nested in the middle of the primary collection tank. The secondary collection tank is connected to an oil outlet pipe extending outward from the top of the tank. A sedimentation pipe extending into the outer vortex tube is connected to the lower end of the primary collection tank. A micro-pressure safety valve is installed at the top of the tank.

[0006] Furthermore, the inner wall of the outer vortex tube is provided with a vertical flow-blocking section, and a vertically extending discharge trough is provided on the side where the water flow impacts; the sedimentation chamber is located between the inner wall of the tank and the outer wall of the outer vortex tube, and a vertically arranged sedimentation plate is provided on the inner wall of the tank corresponding to the discharge trough, and a discharge pipe is connected to the lowest end of the sedimentation chamber.

[0007] Furthermore, the sidewall of the buffer chamber is connected to the spiral channel so that the demulsified wastewater, micro-nano bubbles, and flocculant are mixed and smoothly pushed into the spiral channel.

[0008] Furthermore, the highest point of the inverted U-shaped water pipe is set such that, under normal external pressure, the oil-water interface inside the tank remains at a distance of 10-20 cm below the oil inlet of the secondary collection tank.

[0009] Furthermore, the diameter of the outlet at the lowest end of the sedimentation tube is smaller than the diameter of the sedimentation tube body, which is used to limit the backflow speed of water and promote the sedimentation of impurities.

[0010] Furthermore, the tank body has a sleeve structure support seat connected to the bottommost interior, and the support seat is arranged in the area between the outer vortex tube and the outer shell; when the outer shell is installed into the tank body, the lower end faces of the receiving tube and the sedimentation tube directly abut against the support seat.

[0011] Furthermore, the receiving tube is connected to the reduced diameter of the external sewage pipe through a support base, and the high-speed flow of the sewage pipe generates a Venturi negative pressure suction effect to suck out the tiny impurities collected by the sedimentation shell.

[0012] Furthermore, the back pressure threshold set by the micro-pressure safety valve is 0.03MPa to 0.08MPa, which is used to accumulate pressurized gas in the space reserved at the top of the tank that is not filled with liquid, forming a pneumatic piston pad layer for forced oil discharge by air pressure.

[0013] Furthermore, the oleophilic polymeric filler is one of corrugated oleophilic sheets, modified metal mesh, or modified fiber balls.

[0014] An oilfield wastewater demulsification enhancement treatment process using an oilfield wastewater demulsification enhancement treatment device includes the following five sequential time stages within a single enclosed tank: Step 1, Demulsification and Synchronous Impurity Removal: Oily wastewater is pumped in, and the opening degree is automatically adjusted by the elastic sheet according to the flow rate to maintain turbulence entering the outer vortex tube tangentially; at the same time, heavy impurities are thrown out and settled through the impurity removal tank under centrifugal force; the demulsifier is uniformly mixed into the wastewater under shear force to form demulsified wastewater. Step 2, floc coagulation: Demulsified wastewater enters the buffer chamber, long-chain polymeric flocculant is injected, and after mixing, it enters the area inside the shell below the spiral channel to initially form flocs; Step 3: The mixed gas merges and grows larger with the flocs: The nozzle releases micro-nano bubbles into the spiral channel to be entered, which encapsulate the flocs, oil droplets and bubbles to form extremely light gas-containing flocs, which then merge and grow larger in the spiral channel; Step 4, oil droplet aggregation: The fluid passes through the separator and is forced to change from turbulent flow to laminar flow. Tiny heavy impurities fall into the sedimentation shell and are periodically discharged by negative pressure suction from the external high-speed sewage pipe. Small oil droplets after membrane rupture are captured and aggregate into large oil droplets when flowing over the surface of the oleophilic coagulating packing. Step 5, water-oil separation: The separated clean water enters the clean water chamber, and through the height of the external inverted U-shaped clean water pipe, the static balance of the communicating vessels is used to physically lock a constant oil-water interface in the tank. Step Six: Air Cushion Piston Pressure Filtering Two-Stage Purification and Oil Discharge: Large chunks of pure oil overflow into the first-stage collection tank and then overflow into the second-stage collection tank. Water carried in the first-stage collection tank flows back to the bottom through the sedimentation pipe. As gas escapes or is generated by the bursting of bubbles, it accumulates in the dome. Under the back pressure control of the micro-pressure safety valve, a pressurized air cushion piston is formed, which forcibly forces the pure oil into the oil outlet pipe for discharge.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention constructs four zones—mixing, reaction, aggregation, and separation—from bottom to top within a single tank, allowing wastewater to sequentially undergo high-energy turbulent shear demulsification, helical push low-loss copolymerization, and laminar steady-state aggregation. This spatial structure provides a matching flow field environment for reagent dispersion, floc growth, and oil droplet coalescence, improving reagent utilization and overall oil-water separation efficiency.

[0016] Microbubble copolymerization is introduced to enhance the upward separation rate. Micro- and nano-bubbles are introduced in the early stages of the flocculation reaction, allowing them to directly participate in the copolymerization process of the polymeric flocculant, oil droplets, and fine suspended matter, forming low-density aerated flocs. These aerated flocs grow gently within the push-flow field of the spiral channel, avoiding shear breakage of the polymer chains, and the buoyancy provided by the bubbles significantly improves the upward separation rate in the subsequent gravity separation zone.

[0017] The gravity separation zone utilizes the height setting of the external inverted U-shaped water pipe, based on the principle of static pressure balance in communicating vessels, to physically lock the oil-water interface within the tank, reducing the impact of inlet flow fluctuations on the separation interface. Simultaneously, the accumulation of gas at the top of the tank due to microbubble bursting or water escaping creates a slightly positive pressure gas phase cushion layer controlled by the back pressure of the micro-pressure safety valve. This gas pressure acts downwards on the secondary collection tank, generating a gas pressure thrust that forces the oil into the outlet pipe, resolving the issues of oil adhesion and blockage caused by poor oil flow.

[0018] The tank body adopts a multi-section flange connection, with the lower ends of the receiving pipe and settling pipe inserted and abutting against the support base at the bottom. During maintenance, the internal core components such as the collection tank, packing, and reaction mechanism can be directly lifted upwards by top hoisting, realizing modular insertion and removal positioning of fluid components and reducing the difficulty of equipment maintenance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the tank structure according to Embodiment 1 of the present invention; Figure 2 This is one of the schematic diagrams of the internal structure of the tank in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the full cross-section structure of Embodiment 1 of the present invention; Figure 4 This is the second schematic diagram of the internal structure of the tank in Embodiment 1 of the present invention; Figure 5 yes Figure 4 Enlarged view of a portion of point A in the middle; Figure 6 yes Figure 4 Enlarged view of a section at point B in the middle; Figure 7 This is a schematic diagram of the internal swirling mechanism of the tank in Embodiment 1 of the present invention, omitting the actual swirling mechanism. Figure 8 This is a schematic diagram of the internal extraction reaction mechanism of the tank in Embodiment 1 of the present invention; Figure 9 This is a schematic diagram of the reaction mechanism structure of Embodiment 1 of the present invention; Figure 10 This is a schematic diagram of the swirl mechanism structure of Embodiment 1 of the present invention; Figure 11 This is a schematic diagram of the inner vortex tube structure of Embodiment 1 of the present invention; In the picture: 1. Tank body; 11. Sedimentation chamber; 12. Waste discharge pipe; 13. Water inlet riser; 14. Settling plate; 15. Support base; 2. Swirl mechanism; 21. Outer swirl tube; 211. Flow obstruction section; 212. Impurity discharge groove; 22. Inner swirl tube; 221. Swirl groove; 222. Guide plate; 223. Elastic sheet; 23. Demulsifier tube; 3. Reaction mechanism; 31. Flow stabilizer; 32. Outer shell; 33. Spiral channel; 34. Buffer chamber; 35. Polymer flocculant tube; 36. Micro / nano bubble injection tube; 361. Nozzle; 41. Sedimentation shell; 42. Separator plate; 43. Oleophilic polymeric filler; 44. Barrier plate; 45. Receiving tube; 51. Clear water chamber; 511. Lifting lug; 52. Inverted U-shaped clear water pipe; 53. Primary collection tank; 54. Secondary collection tank; 541. Connecting beam; 55. Oil outlet pipe; 56. Micro-pressure safety valve; 57. Sedimentation pipe. Detailed Implementation

[0020] Example 1 like Figures 1 to 11 As shown, this invention relates to an oilfield wastewater demulsification enhancement treatment device and process. The device includes a vertical cylindrical tank 1, the interior of which, from bottom to top, is constructed with a mixing zone, a reaction zone, a laminar flow accumulation zone, and a gravity separation zone.

[0021] 1. Tank body 1 and supporting structure: Tank 1 is constructed using a multi-section shell assembly, with each section connected by flange bolts for easy transportation, installation, and maintenance. A sleeve-structured support base 15 is fixed inside the lowest part of tank 1, positioned within the annular area between the outer vortex tube 21 and the outer shell 32 of the reaction mechanism 3. The support base 15 contains a flow channel connecting the lower outlet of the receiving pipe 45 and the sedimentation pipe 57. Sealing gaskets are correspondingly provided on the lower end faces of the receiving pipe 45 and the sedimentation pipe 57, ensuring a tight seal between the pipe end faces and the upper end face of the support base 15. Furthermore, the support base 15 is laterally connected to an external sewage discharge pipeline, enabling plug-in and repositioning of the internal pipelines.

[0022] 2. Mixed Zone: This area is located at the bottom of tank 1. A sedimentation chamber 11 is provided at the bottom of tank 1, and a waste discharge pipe 12 is connected to the bottom of sedimentation chamber 11. A vertically upward water inlet riser 13 is arranged inside sedimentation chamber 11, and the upper end of water inlet riser 13 is connected to vortex mechanism 2.

[0023] The swirling mechanism 2 includes an outer swirling cylinder 21 and an inner swirling tube 22 coaxially arranged inside it. The lower end of the inner swirling tube 22 is connected to the water inlet riser 13, and the outer swirling cylinder 21 is assembled to the flange at the upper end of the water inlet riser 13 by fasteners. Multiple swirling grooves 221 are evenly distributed on the outer circumference of the inner swirling tube 22. Each swirling groove 221 has an inclined guide plate 222 on one side of its groove opening to guide the oily wastewater tangentially into the outer swirling cylinder 21. An elastic plate 223 is provided on the other side of the swirling groove 221. The elastic plate 223 can deform with water pressure and adaptively adjust the cross-sectional area of ​​the water passage, so that the wastewater can enter the outer swirling cylinder 21 at a high jet velocity and form a rotating turbulent flow under different inlet flow rates. A demulsifier tube 23 is coaxially inserted into the upper end of the inner swirling tube 22, and its nozzle extends into the area below the swirling groove 221 to inject demulsifier, so that the agent mixes with the wastewater under the swirling shear force.

[0024] The inner wall of the outer vortex tube 21 is provided with a vertical flow-blocking section 211 (e.g., a flow-blocking vertical plate). On the side where the water flow impacts the flow-blocking section 211, a vertically extending impurity discharge channel 212 is provided on the wall of the outer vortex tube 21. Under the action of centrifugal force, denser heavy impurities in the vortex field adhere to the inner wall of the outer vortex tube 21. After being blocked and slowed down by the flow-blocking section 211, they slide out of the impurity discharge channel 212 and fall into the sedimentation chamber 11 located between the outer wall of the outer vortex tube 21 and the inner wall of the tank 1. The inner wall of the sedimentation chamber 11 is provided with vertically arranged impurity settling plates 14 corresponding to the impurity discharge channel 212 to promote the sedimentation of impurities and finally discharge them through the impurity discharge pipe 12.

[0025] 3. Reaction Zone: This area is located in the lower part of tank 1. A flow stabilizer 31 is provided above the outer swirl tube 21 to rectify the rising fluid. A reaction mechanism 3, which can be completely extracted from the top of tank 1, is placed above the flow stabilizer 31.

[0026] The reaction mechanism 3 includes an outer shell 32, inside which is a spiral channel 33, and below the spiral channel 33 is an annular buffer chamber 34. After demulsification, the wastewater passes through a flow stabilizer 31 and first enters the buffer chamber 34. Inside the buffer chamber 34, an annular polymer flocculant tube 35 is arranged, with downward-facing outlet holes for slowly releasing polymer flocculants (such as PAM) into the wastewater. A micro / nano bubble injection tube 36 is also located at the top of the buffer chamber 34, releasing micro / nano bubbles upwards through nozzles 361. Corresponding through holes are provided on the upper wall of the buffer chamber 34 to guide the bubbles directly to the starting position of the spiral channel 33. The sidewall of the buffer chamber 34 communicates with the spiral channel 33. After mixing with the flocculant and micro / nano bubbles, the wastewater is pushed horizontally into the spiral channel 33. The spiral channel 33 transforms the water flow into a horizontal flow pattern. After a preset residence time, the flocculant, oil droplets, and microbubbles co-aggregate to form low-density aerated flocs.

[0027] 4. Laminar flow accumulation zone: Inside the tank 1, located above the outer shell 32, is an inverted conical sedimentation shell 41. A fluid inlet is located on the side wall of the sedimentation shell 41. A baffle plate 42 is installed at the upper end of the sedimentation shell 41. After passing through the baffle plate 42, the fluid flow changes from turbulent to laminar. The area above the baffle plate 42 is densely filled with oleophilic aggregate packing 43 (which can be corrugated oleophilic sheets, modified metal wire mesh, or modified fiber balls, etc.). A baffle plate 44 is installed on top of the oleophilic aggregate packing 43 to restrict its upward movement.

[0028] The sedimentation shell 41 is used to trap small, heavy impurities that fall off before flowing through the packing material. A receiving pipe 45 extending downwards and passing through the outer shell 32 is connected to the lower end of the sedimentation shell 41. The bottom end of the receiving pipe 45 is connected to the narrowing of the external main sewage pipe via a support base 15. Utilizing the Venturi negative pressure suction effect generated by the water flow inside the sewage pipe, the impurities collected by the sedimentation shell 41 are drawn outwards. The outer wall of the receiving pipe 45 also serves as an internal support structure for fixing the blades of the spiral channel 33.

[0029] 5. Gravity separation zone: A downward-extending clear water chamber 51 is provided on the inner wall of the tank 1 above the baffle plate 44. After the water flows through the baffle plate 44, the oil phase floats to the top, and the clear water phase flows laterally into the clear water chamber 51. The bottom of the clear water chamber 51 is connected to an inverted U-shaped clear water pipe 52 extending outside the tank. By setting the elevation of the highest point (overflow point) of the inverted U-shaped clear water pipe 52, based on the principle of static equilibrium of communicating vessels (so that the hydrostatic pressure generated by the external pure water column is balanced with the pressure of the internal oil-water two-phase liquid column), the oil-water interface inside the tank 1 is physically locked at a set distance (such as 10 cm to 20 cm, or 10 cm, 15 cm, or 20 cm) below the oil inlet of the secondary collection tank 54, so as to maintain stable water phase separation.

[0030] The gravity separation zone is equipped with an inverted conical primary collection tank 53 at the top, and a secondary collection tank 54 is nested in the middle of the primary collection tank 53. The top of the secondary collection tank 54 is connected to an oil outlet pipe 55 that extends out of the tank body 1. The lower end of the primary collection tank 53 is connected to a sedimentation pipe 57 that extends downward into the outer vortex cylinder 21. The outlet of the sedimentation pipe 57 has a narrowed diameter design to limit the water flow velocity, so that the trace amount of free water that settles at the bottom of the primary collection tank 53 flows back to the bottom of the equipment for secondary treatment.

[0031] A micro-pressure safety valve 56 is installed at the top of tank 1, which is set with a back pressure threshold (e.g., 0.03 MPa to 0.08 MPa, optionally 0.03 MPa, 0.08 MPa, or preferably 0.05 MPa). In the space where the dome of tank 1 is not filled with liquid, gas released by the bursting of microbubbles or gas associated with raw water accumulates, forming a micro-positive pressure air cushion layer. When high-viscosity pure oil gathers into the secondary collection tank 54, this air cushion layer applies downward static gas pressure to it, forcing the heavy oil into the oil outlet pipe 55 for discharge.

[0032] Working process or working principle (technical flow): The process of implementing enhanced demulsification treatment of oilfield wastewater using the above-mentioned device includes the following stages sequentially within a single tank 1: Step 1, Demulsification and Synchronous Impurity Removal: Oily wastewater is pumped tangentially. When it flows through the vortex tank 221, the elastic sheet 223 deforms adaptively with the flow rate, maintaining the tangential flow of water into the outer vortex tube 21 to form strong turbulence. Heavy impurities are thrown towards the inner wall of the outer vortex tube 21 under centrifugal force, slide out through the impurity removal tank 212 and settle. Demulsifier is injected through the demulsifier pipe 23, and mixes with the wastewater under shear force to break the oil droplet emulsion film.

[0033] Step 2, floc coagulation: After demulsification, the wastewater enters the buffer chamber 34 and mixes with the long-chain polymeric flocculant overflowing from the polymeric flocculant pipe 35 under low shear conditions to form flocs.

[0034] Step 3: Aerated flocs merge and grow: Nozzle 361 releases micro-nano bubbles to the starting point of spiral channel 33. The bubbles combine with flocculant, oil droplets and impurities to form aerated flocs with low density. The mixed fluid is converted into a push flow in spiral channel 33 and grows in a controlled manner.

[0035] Step 4, Flow pattern reduction and oil droplet aggregation: The fluid flows upward through the separator 42, and the flow velocity decreases and turns into laminar flow; the tiny heavy impurities entrained fall into the sedimentation shell 41 and are continuously sucked out by the venturi negative pressure of the external pipeline; the small oil droplets after the membrane breaks adhere to the surface of the oleophilic coalescing packing 43, aggregate into large oil droplets and detach and float to the surface.

[0036] Step 5, Static pressure interface locking and separation: The separated clean water flows into the clean water chamber 51. Utilizing the height of the external inverted U-shaped clean water pipe 52, the internal and external pressures are balanced based on the principle of communicating vessels, thus stably locking the oil-water interface in the tank 1.

[0037] Step Six: Forced Oil Discharge and Purification by Gas Pressure: The floating oil phase overflows into the primary collection tank 53 and further overflows into the secondary collection tank 54, carrying water back to the bottom layer through the sedimentation pipe 57. The escaping gas accumulates at the top of the tank and forms a pressurized air cushion under the control of the micro-pressure safety valve 56, applying downward pressure to the high-viscosity oil in the secondary collection tank 54, forcing it to be discharged from the oil outlet pipe 55.

[0038] During equipment maintenance, the top of the tank 1 can be opened, and the collection component and reaction mechanism 3 can be pulled out from the support base 15 as a whole by using the lifting device that passes through the connecting beam 541 and the lifting lug 511, so as to achieve online maintenance of the core components without draining liquid.

[0039] Multi-stage sleeve linkage online maintenance: When maintenance is required, the top cover of tank 1 can be opened. Using lifting tools, the connecting beam 541 located between the primary collection tank 53 and the secondary collection tank 54 can be hooked to lift the collection tank assembly out. Subsequently, by using the lifting lugs 511 on the inner wall of the clear water chamber 51, the core components such as the reaction mechanism 3 and the oleophilic polymer packing 43 can be lifted out of the tank as a whole module for ground maintenance or replacement. The entire process is efficient and convenient.

[0040] Explanation of the flow direction of wastewater and separated phases: After the oily wastewater enters from the bottom of tank 1, its internal flow path and the final separation path of oil, water, and sludge are as follows: Mainstream path (from bottom to top): External oily wastewater flows upward through the inlet riser 13, tangentially into the outer vortex cylinder 21 via the vortex trough 221, forming an upward vortex that passes through the flow stabilizer 31 and enters the buffer chamber 34. It then enters the spiral channel 33 along the inner wall of the buffer chamber 34, and flows upward in a horizontal, spiraling manner along the spiral channel 33. It then enters the sedimentation shell 41 and flows upward through the partition plate 42, spreading upward through the oleophilic agglomerate packing 43, exiting the baffle plate 44, and entering the gravity separation zone at the top.

[0041] Phase splitting within the gravity separation region: Water phase flow direction: After passing through the baffle plate 44, the clear water phase flows horizontally to the outside and enters the clear water cavity 51 at the tank wall, then flows downward through the inverted U-shaped clear water pipe 52 and is discharged to the outside of the tank.

[0042] Oil phase flow direction: After coalescence, large oil droplets and gaseous flocs continue to rise and overflow over the weir to the primary collection tank 53, and then overflow into the secondary collection tank 54. Under the static pressure of the top air cushion layer, they are forced out of the tank through the oil outlet pipe 55.

[0043] Internal water phase reflux: The trace amount of free water mixed into the primary collection tank 53 settles under the action of gravity, passes down through the bottom sedimentation pipe 57 through the reaction zone, and flows back to the bottom outer vortex cylinder 21 through the thin tube for secondary separation.

[0044] Flow direction of solid impurities: Large, heavy particles: Under the action of centrifugal force in the outer vortex tube 21, they are thrown out through the impurity discharge tank 212 and fall into the sedimentation chamber 11, and are discharged to the bottom through the impurity discharge pipe 12.

[0045] Tiny suspended impurities: As the water flows up into the sedimentation tank 41, they settle due to the sudden drop in flow velocity and flow into the receiving pipe 45. They are then discharged downwards through the support seat 15 channel by external Venturi negative pressure.

[0046] The descriptions of the orientation and relative positional relationships of the structures in this invention, such as front, back, left, right, up, and down, do not constitute a limitation of this invention, but are merely for the convenience of description.

Claims

1. A device for enhanced demulsification treatment of oilfield wastewater, characterized in that, Includes a tank (1), the interior of which, from bottom to top, is constructed a mixing zone, a reaction zone, a laminar flow aggregation zone and a gravity separation zone; The mixing zone includes a sedimentation chamber (11) at the bottom of the tank (1) and an inlet riser (13) arranged in the sedimentation chamber (11). The upper end of the inlet riser (13) is connected to a vortex mechanism (2). The vortex mechanism (2) includes an outer vortex cylinder (21) and an inner vortex pipe (22) arranged coaxially inside it. The inner vortex pipe (22) has vortex grooves (221) evenly opened on its circumference. One side of the vortex groove (221) is provided with an inclined guide plate (222) to form a tangential inlet. The other side of the vortex groove is provided with an elastic plate (223) that is deformed by water pressure to dynamically adjust the water flow rate entering the outer vortex cylinder (21). A demulsifier pipe (23) arranged coaxially for high-pressure injection of demulsifier is inserted into the upper end of the inner vortex pipe (22). The reaction zone includes a flow stabilizer plate (31) arranged inside the tank (1) and above the outer vortex tube (21). A reaction mechanism (3) that can be pulled out from the top is placed above the flow stabilizer plate (31). The reaction mechanism (3) includes an outer shell (32), a spiral channel (33) inside the outer shell (32), and a buffer chamber (34) located below. A polymer flocculant tube (35) with downward water outlet holes is arranged in a ring inside the buffer chamber (34). A micro-nano bubble injection tube (36) with a nozzle (361) is also provided at the top of the buffer chamber (34). The laminar flow accumulation zone includes an inverted conical sedimentation shell (41) with an inlet located above the outer shell (32). A partition plate (42) is installed at the upper end of the sedimentation shell (41). The partition plate (42) is densely filled with oleophilic polymer filler (43). A barrier plate (44) is installed at the upper end of the oleophilic polymer filler (43). A receiving tube (45) extending downward through the outer shell (32) is connected to the lower end of the sedimentation shell (41). The gravity separation zone is located above the baffle plate (44), and a downward-extending clear water chamber (51) is provided near the inner wall of the tank (1). The clear water chamber (51) is connected to an inverted U-shaped clear water pipe (52) extending outward to lock the internal oil-water interface. An inverted cone-shaped primary collection tank (53) is provided above the gravity separation zone. A secondary collection tank (54) is nested in the middle of the primary collection tank (53). The secondary collection tank (54) is connected to an oil outlet pipe (55) extending outward from the top of the tank (1). The lower end of the primary collection tank (53) is connected to a sedimentation pipe (57) extending into the outer vortex tube (21). A micro-pressure safety valve (56) is installed at the top of the tank (1).

2. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The inner wall of the outer vortex tube (21) is provided with a vertical flow-blocking part (211), and a discharge groove (212) that runs through the top and bottom is provided on the side where the water flow impacts; the sedimentation chamber (11) is located between the inner wall of the tank (1) and the outer wall of the outer vortex tube (21), and a vertically arranged sedimentation plate (14) is provided on the inner wall of the tank (1) corresponding to the discharge groove (212), and the bottom end of the sedimentation chamber (11) is connected to a discharge pipe (12).

3. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The sidewall of the buffer chamber (34) is connected to the spiral channel (33) so that the wastewater after demulsification is mixed with micro-nano bubbles and flocculants and then smoothly pushed into the spiral channel (33).

4. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The highest point of the inverted U-shaped water pipe (52) is set to be such that, under normal external pressure, the oil-water interface inside the tank (1) always remains 10 to 20 centimeters below the oil inlet of the secondary collection tank (54).

5. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The diameter of the outlet at the lowest end of the sedimentation tube (57) is smaller than the diameter of the main body of the sedimentation tube (57), which is used to limit the backflow speed of water and promote the sedimentation of impurities.

6. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The tank (1) has a sleeve structure support seat (15) connected to the bottom of the tank. The support seat (15) is arranged in the area between the outer vortex tube (21) and the outer shell (32). When the outer shell (32) is installed into the tank (1), the lower end faces of the receiving tube (45) and the sedimentation tube (57) directly abut against the support seat (15).

7. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The receiving tube (45) is connected to the narrowed section of the external sewage pipe through the support base (15). The high-speed flow of the sewage pipe generates a Venturi negative pressure suction effect, which sucks out the tiny impurities collected by the sedimentation shell (41).

8. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The back pressure threshold set by the micro-pressure safety valve (56) is 0.03MPa to 0.08MPa. It is used to accumulate pressurized gas in the space reserved at the top of the tank (1) that is not filled with liquid, and to form a pneumatic piston pad for forced oil discharge by air pressure.

9. The oilfield wastewater demulsification and enhanced treatment device according to claim 1, characterized in that, The oleophilic polymeric filler (43) is one of corrugated oleophilic plates, modified metal wire mesh, or modified fiber balls.

10. A demulsification enhancement treatment process for oilfield wastewater using the oilfield wastewater demulsification enhancement treatment device according to any one of claims 1-9, characterized in that, The process involves the following five sequential phases within a single enclosed tank (1): Step 1, Demulsification and Synchronous Impurity Removal: Oily wastewater is pumped in, and the opening degree of the elastic sheet (223) is automatically adjusted according to the flow rate to maintain turbulence entering the outer vortex tube (21) tangentially; at the same time, heavy impurities are thrown out and settled through the impurity removal tank (212) under centrifugal force; the demulsifier is evenly mixed into the wastewater under shear force to form demulsified wastewater; Step 2, floc coagulation: Demulsified wastewater enters the buffer chamber (34), long-chain polymer flocculant is injected, and after mixing, it enters the area inside the shell below the spiral channel (33) to initially form flocs; Step 3: The gas mixed in merges with the flocs and grows larger: The nozzle (361) releases micro-nano bubbles into the spiral channel (33) to be entered, which encapsulate the flocs, oil droplets and bubbles to form a gas-containing flocs with extremely light density, and merge and grow larger in the spiral channel (33); Step 4, oil droplet aggregation: The fluid passes through the separator (42) and is forced to change from turbulent flow to laminar flow. Tiny heavy impurities fall into the sedimentation shell (41) and are periodically discharged by negative pressure suction from the external high-speed sewage pipe. Small oil droplets after membrane rupture are captured and aggregated into large oil droplets when flowing through the surface of the oleophilic coagulating packing (43). Step 5, water-oil separation: The separated clean water enters the clean water chamber (51), and through the height of the external inverted U-shaped clean water pipe (52), the static balance of the communicating vessels is used to physically lock the constant oil-water interface in the tank; Step 6: Air cushion piston pressure filtration two-stage purification and oil discharge: Large pieces of pure oil overflow into the first-stage collection tank (53) and then overflow into the second-stage collection tank (54). The water in the first-stage collection tank (53) flows back to the bottom through the sedimentation pipe (57). As the gas generated by the escape or bubble burst accumulates in the dome, it is controlled by the back pressure of the micro-pressure safety valve (56) to form a pressurized air cushion piston, which forcibly forces the pure oil into the oil outlet pipe (55) for discharge.

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