Gradient type oil-solid and water pure physical separation system and method for MTO washing water

Abstract

The invention relates to the technical field of washing water treatment, and discloses a gradient type oil-solid and water pure physical separation system and method for MTO washing water.The separation system comprises a liquid inlet pipe, a liquid inlet valve and a liquid inlet pump are installed on the liquid inlet pipe, and a secondary deslagging system, a secondary oil-water separation system and a buffer water storage tank are sequentially connected to the liquid inlet pipe in the liquid inlet direction; a liquid level sensor and a backwashing system are mounted on the buffer water storage tank; the backwashing system is sequentially communicated with the secondary deslagging system and the secondary oil-water separation system; a buffer flow guide mechanism is installed at the liquid inlet end of the second-stage deslagging system, and a stepped filler assembly is installed in the second-stage deslagging system. A physical gradient separation process is adopted, step-by-step accurate removal from macroscopic particles to microscopic emulsified oil and efficient recovery of oil phase components in wastewater can be realized, the turbidity and solid content indexes of effluent are remarkably improved, and long-period continuous stable operation can be realized.

Description

Technical Field

[0001] This invention relates to the field of water washing treatment technology, and in particular to a gradient-type physical separation system and method for oil-solid and water purity in MTO water washing. Background Technology

[0002] In the MTO (methanol to olefins) process, the washing water contains a large amount of pollutants such as catalyst fine powder, emulsified oil, and wax. If not properly treated, it can lead to blockage of subsequent equipment, reduced heat exchange efficiency, and seriously affect the continuity of production.

[0003] Existing treatment technologies mainly rely on physical separation, chemical agents, and periodic cleaning: oil-water separation and large solid particles are initially separated and removed by density difference through oil separators and cyclone separators; fine catalyst powder is removed by automatic backwash filters; chemical dispersants are added in part to alleviate clogging, and online steam washing or offline cleaning during shutdown is used to restore system function.

[0004] However, existing technologies have significant drawbacks: chemical dispersants easily break down oil and wax into fine particles, which are prone to re-precipitation and exacerbate blockage, and may also interfere with subsequent wastewater treatment; cyclone separators can only remove catalyst particles larger than 10µm, and broken catalysts of about 1µm can easily cause clogging of the oil removal system, lacking oil-solid synergistic removal technology; filtration systems are easily contaminated by oil and wax, requiring frequent backwashing, making long-term stable operation difficult, and relying on shutdowns for cleaning affects production efficiency; the operation process has high energy and material consumption, and pollutants are mostly disposed of as hazardous waste, resulting in low resource utilization and high environmental risks.

[0005] To address this, a gradient-type physical separation system and method for oil-solid and water purity in MTO wash water is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a gradient-type physical separation system and method for oil-solid and water purity in MTO wash water, aiming to solve or improve at least one of the above-mentioned technical problems.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides a gradient oil-solid and water-purity physical separation system for MTO washing water, including an inlet pipe, an inlet valve and an inlet pump installed on the inlet pipe, and a secondary slag removal system, a secondary oil-water separation system and a buffer water storage tank connected sequentially along the inlet direction on the inlet pipe; The buffer water storage tank is equipped with a liquid level sensor and a backwashing system, and the backwashing system is connected in sequence to the secondary slag removal system and the secondary oil-water separation system. The liquid inlet of the secondary slag removal system is equipped with a buffer flow guiding mechanism, and the secondary slag removal system is equipped with a stepped packing assembly.

[0008] According to the present invention, a gradient-type oil-solid and water-pure physical separation system for MTO wash water is provided. The secondary slag removal system includes a low-precision slag removal tank and a high-precision slag removal tank, and the secondary oil-water separation system includes a low-precision oil removal tank and a high-precision oil removal tank. The low-precision slag removal tank, the high-precision slag removal tank, the low-precision oil removal tank, and the high-precision oil removal tank are sequentially installed on the inlet pipe along the liquid inlet direction. The low-precision slag removal tank, the high-precision slag removal tank, the low-precision oil removal tank, and the high-precision oil removal tank are all connected to the backwashing system. The buffer flow guiding mechanism is installed at the inlet end of both the low-precision slag removal tank and the high-precision slag removal tank. The stepped packing assembly includes a first gradient packing and a second gradient packing. The first gradient packing is installed in the low-precision slag removal tank, and the second gradient packing is installed in the high-precision slag removal tank. The particle size of the second gradient packing is 30% to 50% of the particle size of the first gradient packing.

[0009] According to the present invention, a gradient oil-solid and water-pure physical separation system for MTO washing water is provided, wherein the structure of the low-precision oil removal tank is the same as that of the high-precision oil removal tank; the low-precision oil removal tank includes a tank body, a perforated plate, a vertical plate, a demulsification unit, and a separation unit; the top of the tank body is provided with an oil discharge assembly, and both sides of the tank body are connected to the inlet pipe through an oil removal inlet and an oil removal outlet, respectively; The perforated plate is installed on the inner side wall of the tank, the vertical plate is installed vertically at the bottom of the perforated plate, the demulsification unit and the separation unit are both installed inside the tank, and the demulsification unit and the separation unit are respectively located on both sides of the vertical plate; The oil removal inlet is connected to the demulsification unit, and the oil removal outlet is connected to the separation unit. The demulsification unit is filled with a composite oleophilic and hydrophobic functional material. The particle size of the composite oleophilic and hydrophobic functional material in the high-precision oil removal tank is 30% to 50% of the particle size of the composite oleophilic and hydrophobic functional material in the low-precision oil removal tank.

[0010] According to the present invention, a gradient oil-solid and water-purity physical separation system for MTO wash water is provided. The backwashing system includes a backwash inlet main pipe and a backwash outlet main pipe. One end of the backwash inlet main pipe is connected to the buffer water storage tank. A backwash pump and four inlet branch pipes are installed on the backwash inlet main pipe. Four outlet branch pipes are installed on the backwash outlet main pipe. An annular porous water distributor is installed at the discharge end of the inlet branch pipe. The inlet ends of the low-precision slag removal tank, the high-precision slag removal tank, and the two tanks are respectively connected to the four outlet branch pipes, and the outlet ends are respectively connected to the four inlet branch pipes. Valves are installed on the outlet branch pipes and the inlet branch pipes.

[0011] According to the present invention, a gradient-type oil-solid and water-purity physical separation system for MTO wash water is provided, wherein the buffer guiding mechanism includes a conical buffer distributor and a multi-stage guiding assembly, and a slag removal inlet is installed on the top of the inner wall of both the low-precision slag removal tank and the high-precision slag removal tank. The slag removal inlet is connected to the inlet pipe, and the conical buffer distributor is installed at the bottom of the slag removal inlet. The multi-stage flow guiding assembly is installed on the inner wall of both the low-precision slag removal tank and the high-precision slag removal tank. The multi-stage flow guiding assembly is located between the conical buffer distributor and the stepped packing assembly.

[0012] According to the present invention, a gradient-type physical separation system for MTO wash water is provided, wherein the multi-stage flow guiding assembly includes a plurality of flow guiding plate bodies, the flow guiding plate bodies are inclined and the plurality of flow guiding plate bodies are arranged alternately.

[0013] According to the present invention, a gradient-type physical separation system for oil-solid and water purity of MTO wash water is provided, wherein the first gradient packing and the second gradient packing have the same structure, and the first gradient packing includes an upper packing, a middle packing and a lower packing arranged from top to bottom.

[0014] According to the present invention, a gradient oil-solid and water-purity physical separation system for MTO wash water is provided, wherein the particle size of the upper layer of the first gradient packing is 3mm to 5mm, the particle size of the middle layer of the first gradient packing is 1mm to 2mm, and the particle size of the lower layer of the first gradient packing is less than 1mm. The particle size of the upper layer of the second gradient packing is 0.9 mm to 2.5 mm, the particle size of the middle layer of the second gradient packing is 0.3 mm to 0.6 mm, and the particle size of the lower layer of the second gradient packing is less than 0.3 mm.

[0015] According to the present invention, a gradient oil-solid and water-purity physical separation system for MTO wash water is provided. The oil discharge assembly includes an oil collection tank and an oil collection pipe. An oil discharge valve is installed on the oil collection pipe. A level gauge is installed in the oil collection tank. The oil collection tank is installed on the top of the tank body. One end of the oil collection pipe is connected to the oil collection tank, and the other end extends into the space between the top wall of the tank body and the perforated plate.

[0016] This invention also provides a gradient-type physical separation method for oil-solid and water purity in MTO wash water, comprising the following steps: Step 1: Turn off the backwash system and turn on the inlet valve and inlet pump; Step 2: Wastewater flows sequentially through the secondary slag removal system, the secondary oil-water separation system, and the buffer storage tank via the inlet pump and inlet pipe, where slag and oil are removed in sequence. When the set backwash trigger conditions are met, the backwash program is executed. Before each backwash program is executed, the oil drain valve of the secondary oil-water separation system is opened to recover the oil phase. After the backwash program is completed, the inlet valve is opened, and the system returns to normal operation. Step 3: When the liquid level monitored by the liquid level sensor exceeds the set maximum threshold, stop the liquid inlet; when the liquid level monitored by the liquid level sensor exceeds the set minimum threshold, turn off the liquid inlet pump. Step 4: Close the drain valve of the secondary oil-water separation system; Step 5: Close the backwash system and the inlet valve; Step 6: Open the drain valve of the secondary oil-water separation system to recover the oil phase. After draining, close the drain valve to complete the separation.

[0017] The present invention discloses the following technical effects: This invention provides an integrated separation system based entirely on physical processes, requiring no chemical additives. Through the synergistic effect of a buffer flow guiding mechanism, stepped packing components, a backwashing system, and a two-stage oil-water separation system, it achieves an organic combination of flow guidance and stabilization, graded packing, and intelligent backwashing. This allows for a purely physical gradient separation process, sequentially performing low-precision slag removal, high-precision slag removal, low-precision demulsification and oil removal, and high-precision demulsification and oil removal, achieving precise removal from macroscopic particles to microscopic emulsified oil. The resulting effluent exhibits deep removal of suspended solids and oily substances, significantly improving turbidity and solids content. This invention reduces the impact load of influent wastewater through a buffering and diversion mechanism, effectively buffering and adapting to fluctuations in influent water quality and quantity. Even when faced with high concentrations or fluctuating impact loads, it can still maintain a stable and efficient operating state. The backwashing system improves the system's anti-fouling ability, effectively preventing the deep accumulation of pollutants in the packing layer, enabling long-term continuous and stable operation. Simultaneously, it can efficiently recover oil phase components from wastewater, producing concentrated oil with low water content, turning waste into treasure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the low-precision slag removal tank in this invention; Figure 3 This is a schematic diagram of the low-precision oil removal tank in this invention.

[0020] The components include: 1. Inlet pipe; 2. Buffer water tank; 3. Low-precision slag removal tank; 4. High-precision slag removal tank; 5. Low-precision oil removal tank; 6. High-precision oil removal tank; 7. Stepped packing assembly; 8. Perforated plate; 9. Vertical plate; 10. Demulsification unit; 11. Separation unit; 12. Backwash inlet main pipe; 13. Inlet branch pipe; 14. Backwash outlet main pipe; 15. Outlet branch pipe; 16. Backwash pump; 17. Annular perforated water distributor; 18. Conical buffer distributor; 19. Multi-stage flow guiding assembly. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Reference Figures 1-3 The present invention provides a gradient oil-solid and water-purity physical separation system for MTO washing water, including an inlet pipe 1, an inlet valve and an inlet pump installed on the inlet pipe 1, and a secondary slag removal system, a secondary oil-water separation system and a buffer water storage tank 2 connected sequentially along the inlet direction on the inlet pipe 1. The buffer storage tank 2 is equipped with a liquid level sensor and a backwashing system. The backwashing system is connected in sequence to a two-stage slag removal system and a two-stage oil-water separation system. The liquid inlet of the secondary slag removal system is equipped with a buffer guide mechanism, and the secondary slag removal system is equipped with a stepped packing assembly 7. With this configuration, the present invention provides an integrated separation system based entirely on physical processes without the addition of any chemical reagents. Through the synergistic effect of the buffer flow guiding mechanism, stepped packing assembly, backwashing system, and two-stage oil-water separation system, it achieves an organic combination of flow guiding and stabilization, graded packing, and intelligent backwashing. It can sequentially perform a pure physical gradient separation process of low-precision slag removal, high-precision slag removal, low-precision demulsification and oil removal, and high-precision demulsification and oil removal, achieving stepwise precise removal from macroscopic particles to microscopic emulsified oil. The suspended solids and oily substances in the treated effluent are deeply removed, and the turbidity and solid content of the effluent are significantly improved. This invention reduces the impact load of influent wastewater through a buffering and diversion mechanism, effectively buffering and adapting to fluctuations in influent water quality and quantity. Even when faced with high concentrations or fluctuating impact loads, it can still maintain a stable and efficient operating state. The backwashing system improves the system's anti-fouling ability, effectively preventing the deep accumulation of pollutants in the packing layer, enabling long-term continuous and stable operation. Simultaneously, it can efficiently recover oil phase components from wastewater, producing concentrated oil with low water content, turning waste into treasure.

[0024] The scheme is further optimized. The secondary slag removal system includes a low-precision slag removal tank 3 and a high-precision slag removal tank 4. The secondary oil-water separation system includes a low-precision oil removal tank 5 and a high-precision oil removal tank 6. The low-precision slag removal tank 3, the high-precision slag removal tank 4, the low-precision oil removal tank 5, and the high-precision oil removal tank 6 are installed sequentially on the inlet pipe 1 along the liquid inlet direction. The low-precision slag removal tank 3, the high-precision slag removal tank 4, the low-precision oil removal tank 5, and the high-precision oil removal tank 6 are all connected to the backwashing system. Both the inlet end of the low-precision slag removal tank 3 and the inlet end of the high-precision slag removal tank 4 are equipped with buffer and flow guiding mechanisms. The stepped packing assembly 7 includes a first gradient packing and a second gradient packing. The first gradient packing is installed in the low-precision slag removal tank 3, and the second gradient packing is installed in the high-precision slag removal tank 4. The particle size of the second gradient packing is 30% to 50% of the particle size of the first gradient packing. The four-stage treatment unit consists of low-precision slag removal tank 3, high-precision slag removal tank 4, low-precision oil removal tank 5, and high-precision oil removal tank 6. During operation, MTO wash water first enters low-precision slag removal tank 3. The first-gradient packing material, with its larger particle size distribution, intercepts large catalyst particles (over 10µm), completing initial slag removal. Subsequently, the water flows into high-precision slag removal tank 4, where the second-gradient packing material, with even finer particle sizes, precisely captures broken catalyst particles (around 1µm), achieving gradient removal of solid contaminants and preventing fine particles from directly entering the oil removal system and causing blockages. Similarly, in the secondary oil-water separation system, low-precision oil removal tank 5 first removes large-particle emulsified oil, and high-precision oil removal tank 6 subsequently removes small-particle emulsified oil, forming a coarse-to-fine graded oil removal logic to improve the efficiency of oil removal.

[0025] The scheme is further optimized. The structure of the low-precision oil removal tank 5 is the same as that of the high-precision oil removal tank 6. The low-precision oil removal tank 5 includes a tank body, a perforated plate 8, a vertical plate 9, a demulsification unit 10, and a separation unit 11. The top of the tank body is equipped with an oil discharge assembly, and the two sides of the tank body are connected to the inlet pipe 1 through the oil removal inlet and the oil removal outlet, respectively. The perforated plate 8 is installed on the inner side wall of the tank, and the vertical plate 9 is installed vertically at the bottom of the perforated plate 8. The demulsification unit 10 and the separation unit 11 are both installed inside the tank, and the demulsification unit 10 and the separation unit 11 are located on both sides of the vertical plate 9, respectively. The oil removal inlet is connected to the demulsification unit 10, and the oil removal outlet is connected to the separation unit 11. The demulsification unit 10 is filled with a composite oleophilic and hydrophobic functional material. The particle size of the composite oleophilic and hydrophobic functional material in the high-precision oil removal tank 6 is 30% to 50% of the particle size of the composite oleophilic and hydrophobic functional material in the low-precision oil removal tank 5. A stable coalescence separation zone is formed between the porous plate 8 and the top of the tank. Larger oil droplets formed after demulsification of the lower packing material float to this area. Due to the significantly reduced water flow disturbance, they are able to fully aggregate and merge, eventually forming even larger oil droplets. This accelerates their rise to the top oil collection tank, significantly improving the recovery efficiency and purity of the oil phase.

[0026] The perforated plate 8 serves to evenly distribute water, while the vertical plate 9 divides the tank into a demulsification zone and a separation zone. The demulsification unit 10 is filled with a composite oleophilic-hydrophobic functional material, and the particle size of the material in the high-precision oil removal tank 6 is 30%–50% of that in the low-precision tank. Water flows into the demulsification unit 10 through the oil removal inlet. The composite oleophilic-hydrophobic material adsorbs oil droplets through physical adsorption, disrupting the emulsion system and causing tiny oil droplets to aggregate into larger droplets. The water then flows through the vertical plate 9 into the separation unit 11. Large oil droplets float to the top of the tank due to density differences, while solid impurities settle or are further intercepted. The top oil discharge assembly collects the floating oil phase, achieving oil-water separation. The graded particle size material design ensures the step-by-step removal of emulsified oil from macroscopic to microscopic levels, improving the purity of the effluent.

[0027] Further optimization of the scheme: The backwashing system includes a backwash inlet main pipe 12 and a backwash outlet main pipe 14. One end of the backwash inlet main pipe 12 is connected to the buffer water storage tank 2. A backwash pump 16 and four inlet branch pipes 13 are installed on the backwash inlet main pipe 12. Four outlet branch pipes 15 are installed on the backwash outlet main pipe 14. An annular multi-hole water distributor 17 is installed at the discharge end of the inlet branch pipe 13. Another inlet branch pipe 13 is installed between the backwash inlet main pipe 12 and the inlet end of the inlet pipe 1. The inlet ends of the low-precision slag removal tank 3, the high-precision slag removal tank 4, and the two tanks are respectively connected to four outlet branch pipes 15, and the outlet ends are respectively connected to four inlet branch pipes 13. Valves are installed on the outlet branch pipes 15 and the inlet branch pipes 13. When the system triggers backwash conditions, the inlet valve is closed, and the backwash pump 16 and the corresponding branch pipe valve are opened. The clean water in the buffer storage tank 2 is transported to the annular multi-hole water distributor 17 through the backwash inlet main pipe 12 and the inlet branch pipe 13. The water distributor sprays backwash water evenly, flushing the packing layer and functional material layer in each tank in the opposite direction to the original water flow. After the contaminants are flushed, they are discharged through the outlet branch pipe 15 and the backwash outlet main pipe 14. The annular water distributor ensures uniform coverage of backwash water, avoiding incomplete local flushing. The branch pipeline design can realize single-tank backwashing or multi-tank linkage backwashing without affecting the overall system operation, effectively preventing the accumulation of contaminants and ensuring long-term stable operation.

[0028] The scheme is further optimized. The buffer and diversion mechanism includes a conical buffer distributor 18 and a multi-stage diversion component 19. The top of the inner wall of both the low-precision slag removal tank 3 and the high-precision slag removal tank 4 are equipped with slag removal inlets. The slag removal inlets are connected to the inlet pipe 1. The conical buffer distributor 18 is installed at the bottom of the slag removal inlet. Both the low-precision slag removal tank 3 and the high-precision slag removal tank 4 are equipped with multi-stage flow guiding components 19, which are located between the conical buffer distributor 18 and the stepped packing assembly 7. After the water flows into the slag removal inlet through the inlet pipe 1, the conical buffer distributor 18 first disperses the water flow, reduces the impact velocity, and avoids impact damage to the packing layer. Then the water flows through the multi-stage flow guiding component 19, where the inclined and alternating guide plates form an approximately "S"-shaped flow channel, guiding the water flow to form a stable laminar flow state. This not only prolongs the contact time between the water flow and the packing, improving the slag removal efficiency, but also buffers the fluctuations in the quality and quantity of the inlet water, further equalizes the flow velocity, and suppresses the generation of eddies. This creates stable hydraulic conditions for the rise of oil droplets and the settling of particles, avoiding a decrease in separation effect due to impact load and ensuring the operational stability of the slag removal system.

[0029] Further optimization of the scheme: the multi-stage flow guiding component 19 includes several flow guiding plate bodies, which are inclined and arranged alternately.

[0030] Further optimization of the scheme: the first gradient packing and the second gradient packing have the same structure. The first gradient packing includes an upper layer packing, a middle layer packing and a lower layer packing arranged from top to bottom.

[0031] Further optimization of the scheme: the gradient packing assembly uses basalt packing. Taking the low-precision unit as an example: the particle size of the upper layer of the first gradient packing is 3mm to 5mm, the particle size of the middle layer of the first gradient packing is 1mm to 2mm, and the particle size of the lower layer of the first gradient packing is less than 1mm. The upper layer of the second gradient packing has a particle size of 0.9 mm to 2.5 mm, the middle layer has a particle size of 0.3 mm to 0.6 mm, and the lower layer has a particle size of less than 0.3 mm. When water flows from top to bottom through the packing layer, the upper layer of large-diameter packing first intercepts large particles of impurities, the middle layer of medium-diameter packing intercepts medium-sized particles, and the lower layer of small-diameter packing captures fine particles, forming a progressively refined slag removal logic from top to bottom. This not only improves the removal rate of solid pollutants but also prevents the fine packing from clogging prematurely, extending the service life of the packing. Combined with a backwashing system, it can further enhance the anti-fouling ability.

[0032] The scheme is further optimized. The oil discharge component includes an oil collection tank and an oil collection pipe. An oil discharge valve is installed on the oil collection pipe. A level gauge is installed in the oil collection tank. The oil collection tank is installed on the top of the tank. One end of the oil collection pipe is connected to the oil collection tank, and the other end extends into the space between the top wall of the tank and the perforated plate 8. During oil-water separation, the floating oil phase accumulates at the top of the tank and flows into the oil collection tank. A level gauge monitors the oil level in the collection tank in real time. When the level reaches a set threshold, the drain valve opens, and the oil phase is discharged and recycled through the collection pipe. This structure ensures rapid collection and precise discharge of the oil phase, preventing secondary mixing with the water, while also enabling oil resource recovery and utilization, reducing hazardous waste disposal costs, and improving the system's economic efficiency.

[0033] This invention also provides a gradient-type physical separation method for oil-solid and water purity in MTO wash water, comprising the following steps: Step 1: Turn off the backwash system and turn on the inlet valve and inlet pump; Step 2: Wastewater flows sequentially through the secondary slag removal system, the secondary oil-water separation system, and the buffer storage tank 2 via the inlet pump and inlet pipe 1, undergoing slag and oil removal in sequence. When the set backwash trigger conditions are met, the backwash program is executed. Before each backwash, the oil drain valve of the secondary oil-water separation system is opened to recover the oil phase. After the backwash program is completed, the inlet valve is opened, and the system returns to normal operation. The backwash trigger conditions are 8 hours of continuous unit operation or a cross-bed pressure difference of 0.05 MPa. The system integrates an intelligent control system that automatically triggers the backwash and oil drain programs based on the operating time (e.g., 8 hours) and cross-bed pressure difference (e.g., 0.04 MPa). The backwash duration is 6-10 minutes (adjustable depending on the packing material fouling condition). Step 3: When the liquid level monitored by the liquid level sensor exceeds the set maximum threshold, stop the liquid inlet; when the liquid level monitored by the liquid level sensor exceeds the set minimum threshold, turn off the liquid inlet pump. Step 4: Close the drain valve of the secondary oil-water separation system; Step 5: Close the backwash system and the inlet valve; Step 6: Open the drain valve of the secondary oil-water separation system to recover the oil phase. After draining, close the drain valve to complete the separation.

[0034] Oil discharge module control logic: The system records the oil discharge operation of the oil removal unit at independent time intervals, with the timing starting from the end time of the previous oil discharge operation. Before each automatic backwash program starts, an oil discharge operation will be performed first, with the oil discharge time preset to 3 minutes (adjustable from 1 to 60 minutes depending on the oil content of the influent), ensuring resource recovery and reducing the backwash load.

[0035] Oil draining operation from oil collection tank: When the level gauge in the oil collection tank triggers the upper level alarm, the operator should manually open the drain valve and start the drain pump to drain the oil.

[0036] The oil draining time is approximately 8 minutes, or continues until the oil level in the tank drops to the lower level gauge position.

[0037] After manual confirmation, the drain valve and drain pump are closed to complete the transfer of the recovered oil.

[0038] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0039] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A gradient-type physical separation system for oil-solid and water purity in MTO wash water, characterized in that: It includes an inlet pipe (1), on which an inlet valve and an inlet pump are installed. A secondary slag removal system, a secondary oil-water separation system and a buffer water storage tank (2) are sequentially connected along the inlet direction. The buffer water storage tank (2) is equipped with a liquid level sensor and a backwashing system, and the backwashing system is connected to the secondary slag removal system and the secondary oil-water separation system in sequence. The liquid inlet of the secondary slag removal system is equipped with a buffer guide mechanism, and the secondary slag removal system is equipped with a stepped packing assembly (7).

2. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 1, characterized in that: The secondary slag removal system includes a low-precision slag removal tank (3) and a high-precision slag removal tank (4), and the secondary oil-water separation system includes a low-precision oil removal tank (5) and a high-precision oil removal tank (6). The low-precision slag removal tank (3), the high-precision slag removal tank (4), the low-precision oil removal tank (5), and the high-precision oil removal tank (6) are installed sequentially on the inlet pipe (1) along the liquid inlet direction. The low-precision slag removal tank (3), the high-precision slag removal tank (4), the low-precision oil removal tank (5), and the high-precision oil removal tank (6) are all connected to the backwashing system. The inlet end of the low-precision slag removal tank (3) and the inlet end of the high-precision slag removal tank (4) are both equipped with the buffer flow guiding mechanism. The stepped packing assembly (7) includes a first gradient packing and a second gradient packing. The first gradient packing is installed in the low-precision slag removal tank (3), and the second gradient packing is installed in the high-precision slag removal tank (4). The particle size of the second gradient packing is 30% to 50% of the particle size of the first gradient packing.

3. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 2, characterized in that: The structure of the low-precision oil removal tank (5) is the same as that of the high-precision oil removal tank (6); the low-precision oil removal tank (5) includes a tank body, a perforated plate (8), a vertical plate (9), a demulsification unit (10) and a separation unit (11); the top of the tank body is provided with an oil discharge assembly, and the two sides of the tank body are connected to the inlet pipe (1) through an oil removal inlet and an oil removal outlet, respectively; The perforated plate (8) is installed on the inner side wall of the tank, the vertical plate (9) is installed vertically at the bottom of the perforated plate (8), the demulsification unit (10) and the separation unit (11) are both installed in the tank, and the demulsification unit (10) and the separation unit (11) are located on both sides of the vertical plate (9); The oil removal inlet is connected to the demulsification unit (10), and the oil removal outlet is connected to the separation unit (11). The demulsification unit (10) is filled with a composite oleophilic and hydrophobic functional material. The particle size of the composite oleophilic and hydrophobic functional material in the high-precision oil removal tank (6) is 30% to 50% of the particle size of the composite oleophilic and hydrophobic functional material in the low-precision oil removal tank (5).

4. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 3, characterized in that: The backwash system includes a backwash inlet main pipe (12) and a backwash outlet main pipe (14). One end of the backwash inlet main pipe (12) is connected to the buffer water tank (2). A backwash pump (16) and four inlet branch pipes (13) are installed on the backwash inlet main pipe (12). Four outlet branch pipes (15) are installed on the backwash outlet main pipe (14). An annular perforated water distributor (17) is installed at the discharge end of the inlet branch pipe (13). The inlet ends of the low-precision slag removal tank (3), the high-precision slag removal tank (4), and the two tank bodies are respectively connected to the four outlet branch pipes (15), and the outlet ends are respectively connected to the four inlet branch pipes (13). Valves are installed on the outlet branch pipes (15) and the inlet branch pipes (13).

5. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 2, characterized in that: The buffer flow guiding mechanism includes a conical buffer distributor (18) and a multi-stage flow guiding assembly (19). The top of the inner wall of the low-precision slag removal tank (3) and the high-precision slag removal tank (4) are both equipped with slag removal inlets. The slag removal inlets are connected to the inlet pipe (1). The conical buffer distributor (18) is installed at the bottom of the slag removal inlet. The multi-stage flow guiding assembly (19) is installed on the inner wall of both the low-precision slag removal tank (3) and the high-precision slag removal tank (4). The multi-stage flow guiding assembly (19) is located between the conical buffer distributor (18) and the stepped packing assembly (7).

6. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 5, characterized in that: The multi-stage flow guiding assembly (19) includes several flow guiding plate bodies, which are inclined and arranged alternately.

7. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 2, characterized in that: The first gradient packing and the second gradient packing have the same structure. The first gradient packing includes an upper layer packing, a middle layer packing and a lower layer packing arranged from top to bottom.

8. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 7, characterized in that: The particle size of the upper layer of the first gradient packing is 3mm to 5mm, the particle size of the middle layer of the first gradient packing is 1mm to 2mm, and the particle size of the lower layer of the first gradient packing is less than 1mm. The particle size of the upper layer of the second gradient packing is 0.9 mm to 2.5 mm, the particle size of the middle layer of the second gradient packing is 0.3 mm to 0.6 mm, and the particle size of the lower layer of the second gradient packing is less than 0.3 mm.

9. The gradient-type oil-solid and water-purity physical separation system for MTO wash water according to claim 3, characterized in that: The oil discharge assembly includes an oil collection tank and an oil collection pipe. An oil discharge valve is installed on the oil collection pipe. A level gauge is installed in the oil collection tank. The oil collection tank is installed on the top of the tank body. One end of the oil collection pipe is connected to the oil collection tank, and the other end extends into the space between the top wall of the tank body and the perforated plate (8).

10. A gradient-type physical separation method for oil-solid and water purity in MTO wash water, based on the gradient-type physical separation system for oil-solid and water purity in MTO wash water according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Turn off the backwash system and turn on the inlet valve and inlet pump; Step 2: Wastewater flows through the inlet pump and inlet pipe (1) in sequence through the secondary slag removal system, the secondary oil-water separation system and the buffer storage tank (2) to remove slag and oil in sequence. When the set backwash trigger conditions are met, the backwashing program is executed. Before each backwashing program is executed, the oil discharge valve of the secondary oil-water separation system is opened to recover the oil phase. After the backwashing program is completed, the inlet valve is opened and the system returns to normal operation. Step 3: When the liquid level monitored by the liquid level sensor exceeds the set maximum threshold, stop the liquid inlet; when the liquid level monitored by the liquid level sensor exceeds the set minimum threshold, turn off the liquid inlet pump. Step 4: Close the drain valve of the secondary oil-water separation system; Step 5: Close the backwash system and the inlet valve; Step 6: Open the drain valve of the secondary oil-water separation system to recover the oil phase. After draining, close the drain valve to complete the separation.

Images