Membrane separation and purification device for ethylene glycol production

Abstract

The invention discloses a membrane separation and purification device for ethylene glycol production, and relates to the technical field of membrane separation, the membrane separation and purification device comprises a fixed pressing plate, a movable pressing plate, a plurality of layers of liquid inlet assemblies and membrane separation assemblies, and the liquid inlet assemblies and the membrane separation assemblies are alternately stacked between the fixed pressing plate and the movable pressing plate; the hollow shaft penetrates through the liquid inlet assemblies and the membrane separation assemblies which are arranged in a multi-layer stacking manner; the rotary liquid distribution mechanism is arranged in the liquid inlet area; the central vibration generating mechanism is arranged in the separation area and synchronously operates with the hollow shaft; and the plurality of edge vibration generating mechanisms are uniformly distributed in the separation area and synchronously operate with the hollow shaft. Annular vibration waves generated by the center vibration generation mechanism and radial vibration waves generated by the edge vibration generation mechanism are spread on the membrane supporting net plate and the attached separation membrane and interfere with each other, so that attached or to-be-attached pollutant particles are loosened and stripped; and the on-line and active anti-pollution capability of the device is enhanced.

Description

Technical Field

[0001] This invention relates to the field of membrane separation technology, and in particular to a membrane separation and purification device for ethylene glycol production. Background Technology

[0002] Ethylene glycol, as an important basic chemical raw material, is widely used in polyester fibers, antifreeze, solvents, and other fields. In its production process, whether using ethylene oxide hydration or other processes, the final product is a mixture of ethylene glycol and water. Therefore, efficient dehydration is a key step in obtaining high-purity polymer-grade ethylene glycol. Pervaporation membrane separation technology, due to its advantages such as low energy consumption, high selectivity, and no introduction of a third component, has become an important industrial choice to replace or supplement traditional distillation dehydration.

[0003] However, in practical industrial applications, existing plate-and-frame or spiral wound pervaporation membrane modules suffer from a continuous decline in separation efficiency due to membrane fouling, affecting their long-term operational stability and economic efficiency. The root cause of this problem lies in the fact that the industrial ethylene glycol feed solution being treated often contains trace amounts of macromolecular organic impurities, polymer precursors, and metal ions, in addition to water. During membrane separation, water preferentially permeates through the membrane and is removed, while the aforementioned impurities are trapped and enriched in the liquid boundary layer on the membrane surface. Because the fluid within traditional membrane modules is predominantly plug flow or laminar flow, the shear force on the membrane surface is relatively weak, leading to a stable and continuously thickening boundary layer. Impurities easily adsorb, deposit, and even form a dense gel layer on the membrane surface. This contaminant layer not only hinders the mass transfer of water molecules to the membrane surface, significantly reducing dehydration flux, but may also trigger side reactions due to excessively high local concentrations, damaging the membrane material. Although reducing the feed concentration and performing frequent chemical cleaning can alleviate this problem, the former sacrifices processing capacity, while the latter increases downtime, operating costs, and membrane lifespan. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of continuous decline in separation efficiency caused by membrane fouling in the prior art, which affects its long-term operational stability and economy, and to propose a membrane separation and purification device for ethylene glycol production.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A membrane separation and purification device for ethylene glycol production, comprising:

[0007] A fixed pressure plate and a movable pressure plate are fixed relative to each other by a tension rod;

[0008] The liquid inlet assembly and membrane separation assembly are stacked alternately in multiple layers between the fixed pressure plate and the movable pressure plate, forming a liquid inlet area and a separation area between adjacent liquid inlet assemblies and membrane separation assemblies;

[0009] A hollow shaft runs through the multi-layered stacked liquid inlet assembly and membrane separation assembly. The hollow shaft is connected to and driven to rotate by a drive motor mounted on a fixed pressure plate. A liquid distribution hole is provided on the portion of the hollow shaft corresponding to the liquid inlet area.

[0010] The rotating liquid distribution mechanism, located within the liquid inlet area, is used to transport the liquid from the hollow shaft along a spiral path to the outer edge of the liquid inlet area.

[0011] A central vibration generating mechanism, located within the separation area and operating synchronously with the hollow shaft, is used to apply periodic impacts to the central area of ​​the membrane separation assembly.

[0012] Multiple edge vibration generating mechanisms, evenly distributed within the separation area and operating synchronously with the hollow shaft, are used to apply periodic impacts to the outer edge area of ​​the membrane separation assembly;

[0013] The vibrations generated by the central vibration generating mechanism and the edge vibration generating mechanism interfere with each other on the membrane support mesh plate.

[0014] Preferably, the liquid inlet assembly includes an inner ring and an outer ring that are coaxially sealed and rotatably connected, forming an annular liquid outlet channel between the inner ring and the outer ring. The inner ring has an outlet on its wall that connects the liquid inlet area and the annular liquid outlet channel. The outer ring is provided with an outlet pipe that communicates with the annular liquid outlet channel. The outlet pipes of each layer of the liquid inlet assembly are interconnected.

[0015] Preferably, the rotating liquid distribution mechanism includes a guide belt spirally surrounding the outside of the hollow shaft, one end of the guide belt being fixedly connected to the hollow shaft, the other end of the guide belt being fixedly connected to the inner ring, and the side of the guide belt being close to the surface of the separation membrane.

[0016] Preferably, sealing strips are provided on both sides of the spiral path of the guide belt, the sealing strips are elastically fitted to the surface of the separation membrane, and the sealing strips are arc-shaped and bent toward the hollow shaft.

[0017] Preferably, the inner ring and the outer ring are engaged by opposing trapezoidal support surfaces, and a rolling element is provided between the trapezoidal support surfaces.

[0018] Preferably, the membrane separation assembly includes an outer ring, membrane support mesh plates disposed on both axial sides of the outer ring, and a separation membrane attached to the outside of the membrane support mesh plates; the membrane support mesh plates are sealed and rotatably connected to the hollow shaft, the separation area is formed between the two membrane support mesh plates, and is connected to an external negative pressure suction pipeline.

[0019] Preferably, the central vibration generating mechanism includes:

[0020] A mounting plate fixedly installed on the hollow shaft;

[0021] A fixed ratchet is fixedly installed at the center of the membrane support mesh plate;

[0022] A vibrating ratchet is slidably fitted onto the mounting plate, and a positioning rod is fixedly installed on the side wall of the mounting plate, with the positioning rod slidingly engaged with the vibrating ratchet;

[0023] A compression spring disposed between the vibrating ratchet and the mounting plate causes the fixed ratchet and the vibrating ratchet to mesh with each other.

[0024] When the hollow shaft rotates, the vibrating ratchet is engaged, compresses the compression spring and stores energy. Then, when the ratchet teeth separate, it is driven by the restoring force of the compression spring to strike the fixed ratchet, generating periodic vibration.

[0025] Preferably, the edge vibration generating mechanism includes:

[0026] Two sets of symmetrically rotating pendulums are arranged on the outer ring. Each pendulum has a striking end facing the membrane support mesh and a driving end extending in the opposite direction. The rotating shaft of the pendulum is provided with a torsion spring that causes the striking end to press against the membrane support mesh.

[0027] A drive ring fixed to and rotating with the hollow shaft, the outer contour of the drive ring having continuous arc-shaped protrusions;

[0028] When the hollow shaft rotates, the arc-shaped protrusion periodically pushes against the driving end of the pendulum, causing the striking end to overcome the force of the torsion spring and detach from the membrane support plate. Subsequently, when the arc-shaped protrusion separates from the driving end, the torsion spring drives the striking end to swing back and strike the membrane support plate, generating periodic vibration.

[0029] Preferably, the separation areas of each membrane separation component are interconnected through a drain pipe located at the bottom of the outer ring, and are all connected to the negative pressure suction pipeline.

[0030] Preferably, the separation membrane is a hydrophilic composite membrane for permeation vaporization.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] This invention uses a hollow shaft-driven rotary liquid distribution mechanism to forcibly transform the ethylene glycol feed entering the device into a liquid film moving outward along a spiral path. This not only makes the feed more evenly distributed on the membrane surface, avoiding the distribution dead zones that may exist in traditional plug flow, but more importantly, the spirally moving liquid generates a continuous and enhanced tangential shear force on the separation membrane surface. This can directly and effectively interfere with and reduce the liquid boundary layer on the membrane surface, hindering the retention and initial deposition of impurities in this layer, and fundamentally alleviating the conditions for membrane fouling.

[0033] This invention synchronously drives a central vibration generator and an edge vibration generator located within the separation area via a hollow shaft. The annular vibration wave generated by the central vibration generator and the radial vibration wave generated by the edge vibration generator propagate and interfere with each other on the membrane support mesh and the attached separation membrane. This creates complex, unsteady micro-disturbances on the entire membrane surface. Firstly, the vibration itself can loosen and peel off contaminant particles that are already attached or about to be attached. Secondly, the micro-disturbances generated by the vibration interference, in conjunction with the main shear flow generated by the spiral liquid distribution, completely break the stability of the fluid boundary layer on the membrane surface in traditional devices, preventing it from forming an orderly and stable structure. This greatly enhances the device's online, active anti-fouling capability and is expected to significantly extend the effective cleaning cycle and service life of the membrane.

[0034] In this invention, a fixed pressure plate and a movable pressure plate work together with a tensioning rod to press the multi-layered, alternately stacked unit components, forming a highly modular and compact structure. This allows a single device to integrate a large membrane separation area, achieving the goal of small volume and large processing capacity. At the same time, each separation area is suctioned through a shared negative pressure pipeline, and the purified ethylene glycol from each layer is collected through a connected outlet pipeline. The system has a high degree of integration and is easy for industrial installation, operation, and maintenance. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0036] Figure 2 This is a cross-sectional view of a membrane separation and purification device for ethylene glycol production proposed in this invention.

[0037] Figure 3 This is a schematic diagram of the liquid inlet component in a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0038] Figure 4 This is an exploded structural diagram of the liquid inlet component in a membrane separation and purification device for ethylene glycol production proposed in this invention.

[0039] Figure 5 This is a schematic diagram of the connection relationship between the inner and outer rings of a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0040] Figure 6 This is a schematic diagram of the cross-sectional structure of the flow guide belt in a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0041] Figure 7 This is a cross-sectional schematic diagram of the separation component in a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0042] Figure 8 This is a schematic diagram of the separation component in a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0043] Figure 9 This is a schematic diagram of the membrane support mesh plate in a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0044] Figure 10 for Figure 7 A magnified structural diagram of part A in the middle;

[0045] Figure 11 for Figure 7 A magnified structural diagram of part B in the middle section;

[0046] Figure 12 This is a schematic diagram of the drive ring in a membrane separation and purification device for ethylene glycol production proposed in this invention;

[0047] Figure 13 This is a schematic diagram of the pendulum structure in a membrane separation and purification device for ethylene glycol production proposed in this invention.

[0048] In the diagram: 1. Fixed pressure plate; 2. Movable pressure plate; 3. Tensioning rod; 4. Liquid inlet assembly; 41. Inner ring; 42. Outer ring; 43. Annular liquid outlet channel; 44. Outlet; 45. Liquid outlet pipe; 46. Trapezoidal support surface; 47. Rolling element; 5. Membrane separation assembly; 51. Outer ring; 52. Membrane support mesh plate; 53. Separation membrane; 54. Drain pipe; 6. Liquid inlet area; 7. Separation area; 8. Hollow shaft; 81. Cloth 9. Liquid hole; 10. Rotary liquid distribution mechanism; 11. Guide belt; 12. Sealing strip; 13. Central vibration generating mechanism; 14. Mounting plate; 15. Fixed ratchet; 16. Positioning rod; 17. Vibrating ratchet; 18. Compression spring; 19. Edge vibration generating mechanism; 101. Pendulum; 102. Striking end; 113. Drive end; 114. Torsion spring; 115. Drive ring; 116. Arc-shaped protrusion. Detailed Implementation

[0049] Reference Figure 1-7 A membrane separation and purification device for ethylene glycol production is mainly used in the ethylene glycol production process. It aims to efficiently dehydrate and purify a mixed solution of ethylene glycol and water through membrane separation technology to obtain a high-purity ethylene glycol product. Its working environment involves industrial liquid containing ethylene glycol, water and a small amount of impurities. The device includes a fixed pressure plate 1, a movable pressure plate 2, a liquid inlet assembly 4, a membrane separation assembly 5, a hollow shaft 8, a rotating liquid distribution mechanism 9, a central vibration generating mechanism 10 and an edge vibration generating mechanism 11.

[0050] Fixed pressure plate 1 and movable pressure plate 2 are structural support components of the device, used to apply pressure to the internally stacked liquid inlet assembly 4 and membrane separation assembly 5 in the axial direction to ensure the sealing and stability between the liquid inlet assembly 4 and the membrane separation assembly 5. Fixed pressure plate 1 and movable pressure plate 2 are connected and fixed by tension rod 3 to form a compact integral structure. Tension rod 3 is a threaded rod, which is tightened by nut, thereby pressing the components between fixed pressure plate 1 and movable pressure plate 2 together.

[0051] Reference Figure 2-6 The liquid inlet assembly 4 and the membrane separation assembly 5 are the core functional units of the device. They are stacked in multiple alternating layers between the fixed pressure plate 1 and the movable pressure plate 2. The liquid inlet assembly 4 and the membrane separation assembly 5 can be designed as circular or square plate structures. Interlayer sealing is achieved through gaskets or sealing rings. The liquid inlet assembly 4 is responsible for introducing the liquid to be treated, while the membrane separation assembly 5 is responsible for separating and purifying the liquid.

[0052] Two functional areas are formed between the adjacent liquid inlet assembly 4 and membrane separation assembly 5: the liquid inlet area 6 and the separation area 7. The liquid inlet area 6 is the area where the liquid is introduced and initially distributed, while the separation area 7 is the area where the liquid undergoes permeation vaporization separation.

[0053] The hollow shaft 8 is the central transmission component of the device, passing through the multi-layer stacked liquid inlet assembly 4 and membrane separation assembly 5. One end of the hollow shaft 8 is connected to a drive motor mounted on the fixed pressure plate 1 and is driven to rotate by it. The drive motor realizes the rotational motion, thereby driving the internal mechanism connected to it to rotate synchronously. The other end of the hollow shaft 8 is equipped with a union joint, which connects to the raw material feed pipe. Due to the union joint, the hollow shaft 8 maintains a sealed connection with the raw material feed pipe when it rotates. The portion of the hollow shaft 8 corresponding to the liquid inlet area 6 is provided with a liquid distribution hole 81, which is used to transport the liquid from the shaft to the liquid inlet area 6.

[0054] The rotating liquid distribution mechanism 9 is located in the liquid inlet area 6. Its function is to transport the liquid from the hollow shaft 8 along the spiral path to the outer edge of the liquid inlet area 6. Through this spiral motion, the liquid can form a uniform liquid film on the membrane surface and generate tangential shear force.

[0055] A central vibration generator 10, located within the separation zone 7 and operating synchronously with the hollow shaft 8, applies periodic impacts to the central region of the membrane separation assembly 5. Multiple edge vibration generators 11, evenly distributed within the separation zone 7 and operating synchronously with the hollow shaft 8, apply periodic impacts to the outer edge region of the membrane separation assembly 5. This generates vibrations on the membrane support mesh 52, which interfere with the membrane support mesh 52, enhancing the membrane surface's antifouling ability.

[0056] Reference Figure 2-6Specifically, the membrane separation assembly 5 includes an outer ring 51, membrane support mesh plates 52 disposed on both axial sides of the outer ring 51, and a separation membrane 53 attached to the outside of the membrane support mesh plates 52; the membrane support mesh plates 52 and the hollow shaft 8 are connected by a sealed rotational connection; the separation area 7 is formed between the two membrane support mesh plates 52 and is connected to an external negative pressure suction pipeline.

[0057] Among them, the outer ring 51 is a ring structure, and its main function is to provide structural support and boundary definition for the membrane separation component 5. The membrane support mesh plate 52 is a structure used to support the separation membrane 53. Its design needs to ensure that it provides sufficient support strength, does not hinder the effective passage of permeate, and can withstand vibration and impact. The membrane support mesh plate 52 can be in the form of a perforated plate, a mesh structure, etc.

[0058] The membrane support mesh 52 and the hollow shaft 8 are connected by a sealed rotational connection to prevent fluid leakage in the inlet area 6 and the separation area 7 through the connection when the hollow shaft 8 rotates. The separation area 7 is formed between the two membrane support meshes 52 and is connected to an external negative pressure suction line. The separation area 7 is the space where the permeate collects and is extracted after passing through the separation membrane 53. The structure of the membrane support mesh 52 is used to define and support this area. It is connected to an external negative pressure suction line. This area can be evacuated or maintained in a negative pressure state, thereby providing driving force for the permeation process and ensuring that the permeate can be removed continuously and efficiently.

[0059] Reference Figure 2-6 Specifically, the liquid inlet assembly 4 includes an inner ring 41 and an outer ring 42 with a coaxial sealing and rotating connection. These two annular structures are coaxially arranged to ensure rotational stability and allow relative rotation through the sealing and rotating connection. With the aid of O-rings, lip seals or mechanical seals, etc., the liquid will not leak from the connection during rotation. An annular liquid outlet channel 43 is formed between the inner ring 41 and the outer ring 42. The annular liquid outlet channel 43 is used to collect and discharge the purified liquid after membrane separation. It is located between the inner ring 41 and the outer ring 42 and is distributed in a ring shape. It can uniformly collect the liquid from the liquid inlet area 6. The annular liquid outlet channel 43 is formed by machining grooves on the inner wall of the outer ring 42.

[0060] The inner ring 41 has an outlet 44 on its wall that connects the liquid inlet area 6 and the annular liquid outlet channel 43. The outlet 44 is the path for the liquid to enter the annular liquid outlet channel 43 from the liquid inlet area 6, ensuring that the liquid can flow smoothly and evenly into the annular liquid outlet channel 43. It can be a circular hole, a rectangular groove or a perforated plate structure.

[0061] An outlet pipe 45 connected to the annular outlet channel 43 is provided on the outer ring 42. The pipe that leads the liquid collected in the annular outlet channel 43 out of the inlet component 4 is fixed on the outer ring 42 and connected to the annular outlet channel 43. The outlet pipes 45 of each layer of inlet component 4 are interconnected. In the multi-layer stacked device, the outlet pipes 45 of each inlet component 4 are connected together to form a common discharge channel, simplifying the external pipeline connection and realizing centralized collection and discharge.

[0062] Specifically, the rotating liquid distribution mechanism 9 includes a guide belt 91 spirally surrounding the hollow shaft 8. One end of the guide belt 91 is fixedly connected to the hollow shaft 8, and the other end is fixedly connected to the inner ring 41. The side of the guide belt 91 is close to the surface of the separation membrane 53. The guide belt 91 is a spiral-shaped structural component whose main function is to guide the fluid to flow along a preset spiral path. The guide belt 91 is made of a rigid material, such as stainless steel or hard plastic, and is formed into a precise spiral structure through CNC machining to ensure the stability of the fluid path. A spacer rod is provided to support the flow guide 91. The flow guide 91 can rotate synchronously with the hollow shaft 8, thereby driving the liquid to rotate within the liquid inlet area 6. The outer end of the flow guide 91 is fixedly connected to the inner ring 41, so that the entire spiral structure of the flow guide 91 can maintain its shape and position when the hollow shaft 8 rotates, and form a stable boundary with the inner ring 41. The side of the flow guide 91 is close to the surface of the separation membrane 53, which guides the liquid flow to the maximum extent, reduces the short circuit or stagnation of the liquid on the unexpected path, and generates shear force on the membrane surface to a certain extent, which helps to reduce membrane fouling.

[0063] Specifically, sealing strips 92 are provided on both sides of the spiral path of the guide band 91. The sealing strips 92 are elastically attached to the surface of the separation membrane 53, and the sealing strips 92 are arc-shaped and bent towards the hollow shaft 8. Their main function is to prevent fluid short-circuiting or bypassing and to ensure that the fluid flows along the preset path. Since the sealing strips 92 are in a bent state, they can rely on their own elastic deformation to make close contact with the surface of the separation membrane 53 during installation or operation, forming a continuous sealing interface. At the same time, under the positive pressure of the liquid inlet area 6, the sealing strips 92 tend to stick tightly to the surface of the separation membrane 53. This kind of contact allows for compensation within a certain range of manufacturing tolerances, assembly errors, or minor deformations that may occur during operation, thereby maintaining an effective sealing effect.

[0064] The solution of this application effectively solves the problems of liquid bypass and uneven distribution by setting sealing strips 92 on both sides of the spiral path of the guide belt 91 and making these sealing strips 92 elastically fit with the surface of the separation membrane 53. When the hollow shaft 8 drives the guide belt 91 to rotate, the sealing strips 92, due to their elastic properties, always maintain close contact with the surface of the separation membrane 53, forming a dynamic sealing boundary. This strictly confines the liquid in the liquid inlet area 6 within the spiral channel defined by the guide belt 91. Under the action of the rotating liquid distribution mechanism 9, the liquid is forced to be uniformly transported along the spiral path from the hollow shaft 8 to the outer edge of the liquid inlet area 6, avoiding short-circuiting or bypassing of the liquid at the gap between the guide belt 91 and the separation membrane 53. This ensures that the liquid can fully and uniformly cover the entire effective surface of the separation membrane 53, thereby maximizing the membrane utilization efficiency and providing stable feeding conditions for the separation process.

[0065] Reference Figure 5 This application further proposes that the inner ring 41 and the outer ring 42 are engaged by opposing trapezoidal support surfaces 46, and a rolling element 47 is provided between the trapezoidal support surfaces 46. The opposing trapezoidal support surfaces 46 on the inner ring 41 and the outer ring 42 provide a precise running track and bearing surface for the rolling element 47. When the inner ring 41 or the outer ring 42 rotates relative to each other, the rolling element 47 rolls between the trapezoidal support surfaces 46, converting the sliding friction that might have been generated into rolling friction, reducing the driving torque required for rotation and reducing energy loss. At the same time, the design of the trapezoidal support surfaces 46 enables the rolling element 47 to effectively withstand the combined loads from the radial and axial directions, ensuring the coaxiality and stability of the inner ring 41 and the outer ring 42 under high speed or long-term operation.

[0066] Reference Figure 7-12Specifically, the central vibration generating mechanism 10 includes a mounting plate 101 fixedly mounted on the hollow shaft 8, rotating synchronously with the rotation of the hollow shaft 8; a fixed ratchet 102 fixedly disposed at the center of the membrane support mesh plate 52; and a vibration ratchet 104 slidably sleeved on the mounting plate 101. The fixed ratchet 102 is fixedly disposed at the center of the membrane support mesh plate 52, serving as the target component periodically struck by the vibration ratchet 104, directly transmitting the impact force to the central area of ​​the membrane support mesh plate 52, thereby inducing the vibration of the membrane support mesh plate 52. A positioning rod 103 is fixedly mounted on the side wall of the mounting plate 101, and the positioning rod 103 is connected to... The vibrating ratchet 104 is slidably engaged. The positioning rod 103 restricts the rotation of the vibrating ratchet 104, making it rotate synchronously with the mounting plate 101, and guides it to slide precisely along the axial direction to ensure correct engagement and disengagement with the fixed ratchet 102. The compression spring 105, located between the vibrating ratchet 104 and the mounting plate 101, makes the fixed ratchet 102 mesh with the vibrating ratchet 104. When the hollow shaft 8 rotates, the vibrating ratchet 104 is engaged, compressing the compression spring 105 and storing energy. Then, when the ratchet teeth separate, it is driven by the restoring force of the compression spring 105 to strike the fixed ratchet 102, generating periodic vibration.

[0067] The central vibration generating mechanism 10 of this application converts the continuous rotational motion of the hollow shaft 8 into periodic impacts on the central region of the membrane support mesh plate 52. Specifically, when the drive motor drives the hollow shaft 8 to rotate, the mounting plate 101 fixedly mounted on the hollow shaft 8 rotates synchronously. The vibration ratchet 104 is slidably sleeved on the mounting plate 101 and, guided by the positioning rod 103, can slide axially while rotating. The fixed ratchet 102 is fixed at the center position of the membrane support mesh plate 52. During the rotation of the hollow shaft 8, the teeth of the vibration ratchet 104 periodically mesh with the teeth of the fixed ratchet 102. Each time they mesh, due to the action of the teeth, the vibration ratchet 104... 04 will be forced to slide axially toward the mounting plate 101, thereby compressing the compression spring 105 set between it and the mounting plate 101, allowing the spring to store energy. When the teeth of the vibrating ratchet 104 separate from the teeth of the fixed ratchet 102, the compressed spring 105 will quickly release its stored energy, driving the vibrating ratchet 104 to rebound rapidly axially and violently impact the fixed ratchet 102, and then re-engage. The periodic impact force is transmitted to the central area of ​​the membrane support mesh plate 52 through the fixed ratchet 102, thereby generating periodic vibration on the membrane support mesh plate 52, reducing the risk of membrane fouling in this area, avoiding local scaling or clogging, and maintaining membrane flux and separation efficiency.

[0068] Reference Figure 7-13Specifically, the edge vibration generating mechanism 11 includes two sets of symmetrically rotating pendulums 111 mounted on the outer ring 51. The pendulums 111 are the core components of the edge vibration generating mechanism 11, generating vibration by periodically striking the membrane support mesh plate 52. Each pendulum 111 has a striking end 112 facing the membrane support mesh plate 52 and a driving end 113 extending in the opposite direction. A torsion spring 114 is provided on the rotating shaft of the pendulum 111, causing its striking end 112 to tend to press against the membrane support mesh plate 52. A driving ring 115 is fixed to the hollow shaft 8 and rotates with it. The outer contour of the driving ring 115 has continuous arc-shaped protrusions 116. The arc-shaped protrusions 116 are designed to... The continuous structure on the outer contour of the drive ring 115 periodically contacts and pushes against the drive end 113 of the pendulum 111, thereby controlling the movement of the pendulum 111. The shape and number of the arc-shaped protrusions 116 determine the driving frequency and stroke of the pendulum 111. When the hollow shaft 8 rotates, the arc-shaped protrusions 116 periodically push against the drive end 113 of the pendulum 111, causing the striking end 112 to overcome the force of the torsion spring 114 and detach from the membrane support plate 52. Subsequently, when the arc-shaped protrusions 116 separate from the drive end 113, the torsion spring 114 drives the striking end 112 to swing back and strike the membrane support plate 52, generating periodic vibration.

[0069] The aforementioned edge vibration generating mechanism 11 achieves periodic impact on the outer edge region of the membrane support mesh plate 52. Specifically, when the hollow shaft 8 rotates continuously under the action of the drive motor, the drive ring 115 fixed on the hollow shaft 8 also rotates synchronously. The continuous arc-shaped protrusions 116 provided on the outer contour of the drive ring 115 periodically contact and push against the driving end 113 of the pendulum 111 provided on the outer ring 51 during rotation. During the process of the arc-shaped protrusions 116 pushing against the driving end 113, the striking end 112 of the pendulum 111 overcomes the preload of the torsion spring 114 and gradually moves away from the membrane support mesh plate 52, thereby accumulating energy. When the arc-shaped protrusions 116 push against the driving end 113, the striking end 112 of the pendulum 111 overcomes the preload of the torsion spring 114 and gradually moves away from the membrane support mesh plate 52, thereby accumulating energy. As the pendulum continues to rotate and separates from the driving end 113 of the pendulum 111, the elastic potential energy stored in the torsion spring 114 is rapidly released, driving the striking end 112 of the pendulum 111 to swing back quickly and strike the outer edge area of ​​the membrane support mesh plate 52 with a certain impact force, thereby generating periodic mechanical vibration. Since two sets of symmetrically rotating pendulums 111 are provided, the membrane support mesh plates 52 on both sides of the membrane separation assembly 5 can be struck simultaneously. This periodic mechanical impact can effectively destroy the concentration polarization layer formed on the membrane surface and peel off the pollutants attached to the membrane support mesh plate 52 and the outer edge area of ​​the separation membrane 53, thereby significantly improving the overall separation performance of the membrane separation assembly 5.

[0070] The central vibration generating mechanism 10 and multiple edge vibration generating mechanisms 11, which rotate synchronously with the hollow shaft 8, work in sync. The central vibration generating mechanism 10 applies periodic impacts to the central region of the membrane support mesh plate 52, while the edge vibration generating mechanisms 11 apply periodic impacts to the outer edge region of the membrane support mesh plate 52. These impacts are transmitted to the separation membrane 53 attached thereto through the membrane support mesh plate 52. Due to the synergistic effect of the central vibration generating mechanism 10 and the edge vibration generating mechanisms 11, the generated vibration waves are superimposed on the membrane support mesh plate 52, forming a complex interference mode, which effectively inhibits the adhesion of pollutants on the membrane surface, thereby significantly improving the efficiency and stability of membrane separation and extending the service life of the membrane.

[0071] This application further proposes that the separation regions 7 of each membrane separation assembly 5 are interconnected by drain pipes 54 located at the bottom of the outer ring 51 and are jointly connected to a negative pressure suction pipeline. The permeate inside the separation region 7 formed within each membrane separation assembly 5 needs to be effectively collected. By setting drain pipes 54 at the bottom of the outer ring 51 of each membrane separation assembly 5 and connecting these drain pipes 54 to each other, the permeate in each separation region 7 can be collected in a concentrated manner, ensuring that each separation region 7 can share a negative pressure source and drainage path, thereby simplifying the pipeline layout and helping to achieve a balanced distribution of negative pressure in each separation region 7, thereby improving the overall membrane separation efficiency.

[0072] This application further proposes that the separation membrane 53 is a hydrophilic composite membrane for pervaporation. The membrane material is hydrophilic and can preferentially adsorb and permeate hydrophilic components such as water molecules. It also has a composite structure, which is usually composed of a thin and dense active separation layer and a porous support layer. Pervaporation is a mature membrane separation technology that achieves component separation by selectively allowing one or more components in a mixture to permeate through the membrane in the form of vapor. This will not be elaborated here.

[0073] The specific working process of this invention is as follows:

[0074] The ethylene glycol aqueous solution to be treated enters the continuously rotating hollow shaft 8 through the feed pipe and the union joint, and flows out from the liquid distribution hole 81 to the liquid inlet area 6. In the liquid inlet area 6, the spiral guide belt 91 fixed on the hollow shaft 8 rotates synchronously with the hollow shaft 8, forcing the liquid to move outward along the spiral path. This process makes the liquid uniformly cover the surface of the separation membrane 53, and the tangential fluid shear force generated initially inhibits the adhesion of pollutants.

[0075] The water in the distributed feed solution, driven by the vapor pressure difference across the membrane, preferentially passes through the separation membrane 53 and enters the separation zone 7, where it is quickly extracted as water vapor. The dehydrated concentrated ethylene glycol solution continues to flow along the spiral path and eventually enters the annular liquid outlet channel 43 through the outlet 44 on the inner ring 41. After being collected by the liquid outlet pipe 45, it is discharged as a purified product.

[0076] Meanwhile, the rotation of the hollow shaft 8 synchronously drives the central vibration generating mechanism 10 and the edge vibration generating mechanism 11. The central vibration generating mechanism 10 periodically impacts the center of the membrane support mesh plate 52 through the energy storage and release mechanism of the vibration ratchet 104 and the compression spring 105; the edge vibration generating mechanism 11 periodically strikes the outer edge of the membrane support mesh plate 52 through the pendulum 111. The mechanical vibration waves generated by the two propagate on the membrane support mesh plate 52 and the attached separation membrane 53 and interfere with each other, forming a dynamic and complex micro-disturbance field, which effectively destroys the stable boundary layer on the membrane surface, making it difficult for impurities to deposit. In conjunction with the fluid shear force generated by the spiral liquid distribution, it realizes online and active suppression of membrane fouling, thereby ensuring that the device can maintain high dehydration flux and separation efficiency for a long time.

Claims

1. A membrane separation and purification device for ethylene glycol production, characterized in that, include: Fixed pressure plate (1) and movable pressure plate (2), the fixed pressure plate (1) and movable pressure plate (2) are fixed relative to each other by a tension rod (3); The liquid inlet assembly (4) and membrane separation assembly (5) are stacked alternately in multiple layers between the fixed pressure plate (1) and the movable pressure plate (2), forming a liquid inlet area (6) and a separation area (7) between adjacent liquid inlet assemblies (4) and membrane separation assemblies (5). A hollow shaft (8) runs through the multi-layer stacked liquid inlet assembly (4) and membrane separation assembly (5). One end of the hollow shaft (8) is connected to a drive motor mounted on a fixed pressure plate (1) and driven to rotate by it. The other end is equipped with a live connector. A liquid distribution hole (81) is opened in the part of the hollow shaft (8) corresponding to the liquid inlet area (6). The rotary liquid distribution mechanism (9) installed in the liquid inlet area (6) is used to transport the liquid from the hollow shaft (8) along a spiral path to the outer edge of the liquid inlet area (6); A central vibration generating mechanism (10) is set in the separation area (7) and operates synchronously with the hollow shaft (8) to apply periodic impacts to the central area of ​​the membrane separation assembly (5); Multiple edge vibration generating mechanisms (11) are evenly distributed within the separation region (7) and operate synchronously with the hollow shaft (8) to apply periodic impacts to the outer edge region of the membrane separation assembly (5); The vibrations generated by the central vibration generating mechanism (10) and the edge vibration generating mechanism (11) interfere with each other on the membrane support mesh plate (52).

2. The membrane separation and purification apparatus for ethylene glycol production according to claim 1, characterized in that, The membrane separation assembly (5) includes an outer ring (51), membrane support mesh plates (52) disposed on both sides of the outer ring (51) axially, and a separation membrane (53) attached to the outside of the membrane support mesh plates (52); the membrane support mesh plates (52) and the hollow shaft (8) are connected by a sealed rotational connection, and the separation area (7) is formed between the two membrane support mesh plates (52) and is connected to an external negative pressure suction pipeline.

3. The membrane separation and purification apparatus for ethylene glycol production according to claim 1, characterized in that, The liquid inlet assembly (4) includes an inner ring (41) and an outer ring (42) that are coaxially sealed and rotatably connected. An annular liquid outlet channel (43) is formed between the inner ring (41) and the outer ring (42). The inner ring (41) has an outlet (44) that connects the liquid inlet area (6) and the annular liquid outlet channel (43) on its wall. The outer ring (42) is provided with an outlet pipe (45) that communicates with the annular liquid outlet channel (43). The outlet pipes (45) of each layer of the liquid inlet assembly (4) are interconnected.

4. The membrane separation and purification apparatus for ethylene glycol production according to claim 3, characterized in that, The rotating liquid distribution mechanism (9) includes a guide belt (91) spirally surrounding the outside of the hollow shaft (8). One end of the guide belt (91) is fixedly connected to the hollow shaft (8), and the other end of the guide belt (91) is fixedly connected to the inner ring (41). The side of the guide belt (91) is close to the surface of the separation membrane (53).

5. The membrane separation and purification apparatus for ethylene glycol production according to claim 4, characterized in that, Sealing strips (92) are provided on both sides of the spiral path of the guide strip (91). The sealing strips (92) are elastically attached to the surface of the separation membrane (53), and the sealing strips (92) are arc-shaped and bent toward the hollow shaft (8).

6. The membrane separation and purification apparatus for ethylene glycol production according to claim 3, characterized in that, The inner ring (41) and the outer ring (42) are engaged by opposing trapezoidal support surfaces (46), and a rolling element (47) is provided between the trapezoidal support surfaces (46).

7. The membrane separation and purification apparatus for ethylene glycol production according to claim 1, characterized in that, The central vibration generating mechanism (10) includes: Mounting disc (101) fixedly installed on the hollow shaft (8); A fixed ratchet (102) is fixedly installed at the center of the membrane support mesh plate (52); A vibrating ratchet (104) is slidably sleeved on the mounting plate (101), and a positioning rod (103) is fixedly installed on the side wall of the mounting plate (101). The positioning rod (103) is slidably engaged with the vibrating ratchet (104). A compression spring (105) disposed between the vibrating ratchet (104) and the mounting plate (101) causes the fixed ratchet (102) to mesh with the vibrating ratchet (104); When the hollow shaft (8) rotates, the vibrating ratchet (104) is engaged and compresses the compression spring (105) and stores energy. Then, when the ratchet teeth separate, it is driven by the restoring force of the compression spring (105) to strike the fixed ratchet (102), generating periodic vibration.

8. The membrane separation and purification apparatus for ethylene glycol production according to claim 2, characterized in that, The edge vibration generating mechanism (11) includes: Two sets of symmetrically rotating pendulums (111) are arranged on the outer ring (51). The pendulums (111) have a striking end (112) facing the membrane support mesh (52) and a driving end (113) extending in the opposite direction. The pivot of the pendulums (111) is provided with a torsion spring (114) that causes the striking end (112) to have a tendency to press against the membrane support mesh (52). A drive ring (115) is fixed to the hollow shaft (8) and rotates with it. The outer contour of the drive ring (115) has a continuous arc-shaped protrusion (116). When the hollow shaft (8) rotates, the arc-shaped protrusion (116) periodically pushes against the driving end (113) of the pendulum (111), causing the striking end (112) to overcome the force of the torsion spring (114) and detach from the membrane support plate (52). Subsequently, when the arc-shaped protrusion (116) separates from the driving end (113), the torsion spring (114) drives the striking end (112) to swing back and strike the membrane support plate (52), generating periodic vibration.

9. A membrane separation and purification apparatus for ethylene glycol production according to claim 2, characterized in that, The separation areas (7) of each membrane separation component (5) are interconnected through a drain pipe (54) located at the bottom of the outer ring (51) and are connected to the negative pressure suction pipeline.

10. A membrane separation and purification apparatus for ethylene glycol production according to claim 2, characterized in that, The separation membrane (53) is a hydrophilic composite membrane used for pervaporation.

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