Multifunctional hollow fiber membrane spinning equipment

Abstract

The utility model discloses multifunctional hollow fiber membrane spinning equipment which is characterized by comprising a spinning solution supply unit, a composite spinneret plate, crosslinking equipment, a phase inversion tank and a wire winding wheel, the spinning solution supply unit is connected with the composite spinneret plate, an outlet of the composite spinneret plate faces the cross-linking equipment, the phase inversion tank is arranged below the cross-linking equipment, and the wire winding wheel is arranged on one side of the phase inversion tank; the spinning solution supply unit comprises a plurality of spinning solution tank bodies, a plurality of layers of extrusion channels which are mutually independent are arranged on the composite spinneret plate, and each extrusion channel is connected with the corresponding spinning solution tank body. Due to the fact that the composite spinneret plate is provided with the multiple layers of extrusion channels which are independent of one another, a hollow fiber substrate and a functional layer can be synchronously extruded through the composite spinneret plate, direct interfacial polymerization is conducted in combination with cross-linking equipment below the composite spinneret plate, and therefore the tedious aftertreatment steps are reduced, and the production efficiency can be effectively improved.

Description

Technical Field

[0001] This utility model belongs to the field of membrane separation technology, specifically relating to a multifunctional hollow fiber membrane spinning equipment. Background Technology

[0002] Membrane separation technology, as a highly efficient, environmentally friendly, and selective separation method, has demonstrated immense application value in numerous fields such as water resource treatment, food industry, biomedicine, and chemical industry. Ultrafiltration (UF) and nanofiltration (NF) are two particularly noteworthy membrane separation technologies. Ultrafiltration membranes can effectively retain large molecules, colloids, and bacteria in water, while nanofiltration membranes excel in removing small organic molecules and hardness ions. Both technologies, with their unique separation properties, play a crucial role in ensuring water quality and achieving material purification.

[0003] Traditional nanofiltration membrane fabrication often involves multiple independent and complex processes. First, a substrate membrane spinning process is required to prepare the ultrafiltration or microfiltration substrate membrane. Then, subsequent separate coating processes are needed to construct the functional layer, and additional cross-linking steps may be required to enhance membrane performance. For example, after substrate spinning, complex transfer and positioning operations are necessary before the functional layer coating stage can begin. The transitions between these stages are time-consuming and prone to errors, affecting the quality and stability of the final membrane product.

[0004] A hollow fiber membrane spinning system is disclosed in patent application number CN202121624475.X, which includes an operating table, a stirring tank and a composite spinneret. When using this hollow fiber membrane spinning system, the base membrane needs to be spun first. After the base membrane is prepared, the functional layer is constructed through subsequent separate coating and other processes. Therefore, there are time-consuming issues in the connection between each step, which affects the production efficiency. Utility Model Content

[0005] The purpose of this invention is to provide a multifunctional hollow fiber membrane spinning device to solve the following technical problems mentioned in the background art:

[0006] Existing hollow fiber membrane spinning equipment is too specialized to simultaneously meet the requirements of integrated membrane formation for microfiltration (MF), ultrafiltration (UF), and nanofiltration (NF) using a single machine. Furthermore, there are inconsistencies in the precision control required for hollow fiber membrane fabrication under internal / external pressure.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0008] A multifunctional hollow fiber membrane spinning device includes a spinning solution supply unit, a composite spinneret, a crosslinking device, a phase inversion tank, and a winding wheel. The spinning solution supply unit is connected to the composite spinneret, with the outlet of the composite spinneret facing the crosslinking device. The phase inversion tank is located below the crosslinking device, and the winding wheel is located on one side of the phase inversion tank. The spinning solution supply unit includes a casting solution tank, a core solution tank, and a multifunctional tank. The composite spinneret is provided with multiple independent extrusion channels, each of which is connected to the casting solution tank, the core solution tank, and the multifunctional tank.

[0009] Furthermore, the casting liquid tank is used to store the casting liquid, the core liquid tank is used to store the core liquid, and the multifunctional tank can store both the functional coating / liquid and the casting liquid. The tank uses heat transfer oil heating to achieve a high-temperature environment for storing the casting liquid of the thermal polymer melting process. The composite spinneret is provided with three channels: the inner layer is the core liquid layer, the middle layer is the casting liquid layer, and the outer layer can be both the casting liquid layer and the functional coating layer. Among them, the inner functional liquid layer is connected to the core liquid tank, the outer functional liquid layer is connected to the multifunctional tank, and the casting liquid layer is connected to the casting liquid tank.

[0010] Furthermore, a micro-flow pump is installed between the outer functional liquid layer and the tank body.

[0011] Furthermore, the inner functional liquid layer, the casting liquid layer, and the outer functional liquid layer all have an arc-shaped structure.

[0012] Furthermore, a first reversing wheel is provided at the bottom of the phase conversion tank near the crosslinking equipment.

[0013] Furthermore, a second reversing wheel is provided on the side of the phase inversion tank away from the crosslinking equipment.

[0014] Furthermore, a tension controller is connected to the winding wheel.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] With this design, the composite spinneret has multiple independent extrusion channels, which allows for the simultaneous extrusion of the hollow fiber substrate and functional layer. Combined with the crosslinking equipment below the composite spinneret for direct interfacial polymerization, this reduces cumbersome post-processing steps and effectively improves production efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure and process of this utility model;

[0018] Figure 2 This is a schematic diagram of the composite spinneret of this utility model;

[0019] Figure 3This is a schematic diagram of the internal structure of the composite spinneret of this utility model;

[0020] Figure 4 This is a schematic diagram of the crosslinking device structure of this utility model.

[0021] The markings in the diagram are: 1-spinning solution supply unit, 2-first reversing wheel, 3-phase conversion tank, 4-winding wheel, 5-second reversing wheel, 6-crosslinking equipment, 7-composite spinneret, 8-top section, 9-middle section, 10-bottom section, 11-first connector, 12-second connector, 13-third connector, 14-inner functional liquid layer, 15-casting solution layer, 16-outer functional liquid layer. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Example:

[0024] A multifunctional hollow fiber membrane spinning device includes a spinning solution supply unit 1, a composite spinneret 7, a crosslinking device 6, a phase inversion tank 3, and a winding wheel 4. The spinning solution supply unit 1 is connected to the composite spinneret 7, with the outlet of the composite spinneret 7 facing the crosslinking device 6. The phase inversion tank 3 is located below the crosslinking device 6, and the winding wheel 4 is located on one side of the phase inversion tank 3. The spinning solution supply unit 1 includes a casting solution tank, a core solution tank, and a multifunctional tank. The composite spinneret 7 is provided with multiple independent extrusion channels, each of which is connected to the casting solution tank, the core solution tank, and the multifunctional tank.

[0025] The spinning solution supply unit 1 is used to store and supply spinning solution and coating solution; the spinning solution supply unit 1 is connected to the composite spinneret 7 via a pipeline. The composite spinneret 7 is used for simultaneous extrusion of the substrate and functional layer. The crosslinking equipment 6 is as follows... Figure 4 As shown, the crosslinking equipment is used to simultaneously cure and bond the functional layer and the substrate to form hollow fibers through ultraviolet light curing or thermal crosslinking. In this embodiment, the crosslinking equipment 6 includes, but is not limited to, an ultraviolet radiation crosslinking equipment 6 and an electron beam crosslinking equipment 6. For example, when using the ultraviolet radiation crosslinking equipment 6, the ultraviolet light intensity should be 300 mW / cm2, and the irradiation time should be 5 s. The phase inversion tank 3 has a built-in non-solvent bath for rapid phase inversion molding of the hollow fiber substrate; the water temperature in the phase inversion tank 3 is 25°C, and the residence time of the hollow fiber in the phase inversion tank 3 is not less than 20 s. The winding wheel 4 is used to wind up the hollow fiber.

[0026] When in use, because the composite spinneret 7 is equipped with multiple independent extrusion channels, the hollow fiber substrate and functional layer can be extruded simultaneously through the composite spinneret 7. Then, the cross-linking device 6 below the composite spinneret 7 directly performs interfacial polymerization, thereby reducing cumbersome post-processing steps.

[0027] In a preferred embodiment, the spinning solution supply unit 1 is provided with three tanks: a casting solution tank for storing casting solution, a core solution tank for storing core solution, and a multifunctional tank for storing both functional coatings / liquids and casting solution. The composite spinneret 7 is provided with three rings of extrusion channels, which, from the inside out, are an inner functional liquid layer 14, a casting solution layer 15, and an outer functional liquid layer 16. The inner functional liquid layer 14 is connected to the core solution tank, the outer functional liquid layer 16 is connected to the multifunctional tank, and the casting solution layer 15 is connected to the casting solution tank.

[0028] The inner functional liquid layer 14 is used to extrude the inner functional liquid to form the inner functional layer of the hollow fiber membrane. The casting liquid layer 15 is used to extrude the casting liquid to form the substrate of the hollow fiber membrane. The outer functional liquid layer 16 is used to extrude the outer functional liquid to form the outer functional layer of the hollow fiber membrane. These three layers work together to simultaneously extrude the substrate and the inner and outer functional layers of the hollow fiber membrane. Combined with the crosslinking equipment 6, this achieves integrated membrane formation, reducing post-processing steps.

[0029] It should also be noted that, in this embodiment, the microfiltration / ultrafiltration spinning solution can be a polyethersulfone / NMP solution; the functional coating / liquid can be a polyethyleneimine / pyromellitic trimethylol chloride prepolymer.

[0030] In a preferred embodiment, a micro-flow pump is installed between the outer functional liquid layer 16 and the tank. The micro-flow pump precisely controls the supply of material to the outer functional liquid layer 16, ensuring a functional layer thickness accuracy of ±1μm and guaranteeing the quality stability of the hollow fiber membrane. This effectively avoids excessive material loss in traditional impregnation methods, improves material utilization through precise feeding, and reduces production costs.

[0031] In a preferred embodiment, the inner functional liquid layer 14, the casting liquid layer 15, and the outer functional liquid layer 16 are all arc-shaped structures. This arc-shaped design allows for more uniform distribution of the liquid layers during extrusion, ensuring consistent hollow fiber membrane thickness. Simultaneously, this arc-shaped configuration maintains a clear multi-layer liquid interface, preventing mixing and ensuring the quality of bonding between the functional layers and the substrate.

[0032] In a preferred embodiment, a first reversing wheel 2 is provided at the bottom of the phase inversion tank 3 near the crosslinking device 6. More optimally, a second reversing wheel 5 is provided at the top of the phase inversion tank 3 away from the crosslinking device 6. The first reversing wheel 2 changes the orientation of the hollow fibers, ensuring they fully contact the non-solvent bath within the phase inversion tank 3, extending the immersion time, and ensuring uniform solidification of the substrate. The second reversing wheel 5 further extends the residence time of the fibers in the non-solvent bath, enhancing the phase inversion effect and improving the stability of the membrane structure. Furthermore, the second reversing wheel 5 also ensures that the hollow fibers can be stably wound by the winding wheel 4.

[0033] In a preferred embodiment, a tension controller is connected to the winding wheel 4. Using the tension controller allows for easy adjustment of the rotational speed and traction force of the winding wheel 4, ensuring that the hollow fiber membrane maintains constant tension during winding and preventing membrane fiber breakage or wrinkling due to tension fluctuations. Controlling the tension reduces uneven stress within the membrane fibers, ensuring the stability of key performance parameters such as porosity and pore size distribution of the hollow fiber membrane, and reducing batch-to-batch variations.

[0034] In a preferred embodiment, the composite spinneret 7 includes a top section 8, a middle section 9, and a bottom section 10, which are connected sequentially from top to bottom. An outer functional liquid layer 16 is disposed at the bottom of the bottom section 10, and an inner functional liquid layer 14 is disposed in the middle of the middle section 9. A casting liquid layer 15 is formed between the middle section 9 and the bottom section 10. A channel is disposed in the middle of the top section 8, and the channel is connected to the inner functional liquid layer 14. A first connector 11 is disposed on the top section 8, communicating with the inner functional liquid layer 14. A second connector 12 is disposed on one side of the middle section 9, connecting to the casting liquid layer 15. A third connector 13 is connected to the outer functional liquid layer 16. The inner functional liquid is input through the channel of the top section 8 and the first connector 11, and passes through the inner functional liquid layer 14 of the middle section 9, imparting specific functions to the hollow fiber membrane. The microfiltration spinning solution is introduced through the second connector 12 and flows in the casting solution layer 15 between the middle section 9 and the bottom section 10. After extrusion, it forms the substrate of the hollow fiber membrane, which determines the basic strength and overall shape of the membrane. Finally, an outer functional liquid is introduced through the third connector 13. It is stored and output in the functional liquid layer 16 on the outside of the bottom section 10, forming a functional layer on the outside of the hollow fiber membrane, which plays a role in protection, anti-fouling, and improving hydrophilicity.

[0035] In use, the first connector 11, the second connector 12, and the third connector 13 are connected to the corresponding storage tanks via pipes. Under pressure, different liquids enter the corresponding channel layers within the composite spinneret 7 from their respective connectors. The inner functional liquid is extruded from the innermost channel of the bottom section 10 through the channels of the top section 8 and the inner functional liquid layer 14 of the middle section 9; the casting liquid flows in the casting liquid layer 15 between the middle section 9 and the bottom section 10 and is extruded from the annular channel in the middle of the bottom section 10; the outer functional liquid flows in the outer functional liquid layer 16 of the bottom section 10 and is extruded from the outer channel. The simultaneous extrusion of the three liquids forms a fibrous fluid with a base and inner and outer functional layers. After subsequent curing steps, it is rapidly molded into hollow fibers with multiple functions.

[0036] The production and usage methods are as follows:

[0037] Production and usage method 1:

[0038] In this production method, the external functional liquid layer 16 in the multifunctional reactor and composite spinneret 7 is not used;

[0039] Step 1: Prepare casting solution and core solution.

[0040] The casting solution includes 18 parts of polyvinylidene fluoride (PVDF), 30 parts of hydrophilic additives, and 50 parts of organic solvent DMAc; the hydrophilic additives are prepared by mixing PVPk30 and PEG400 in a 1:3 ratio.

[0041] The core fluid consists of organic and non-organic solvents. Specifically, the core fluid is prepared by mixing DMAc and water in a 4:6 ratio.

[0042] Step 2: Spinning.

[0043] The casting solution and the core solution are simultaneously ejected from the composite spinneret 7. The inner functional liquid layer 14 is the core solution and the casting solution layer 15 is the casting solution. The spinning temperature is 60℃, the core solution temperature is 60℃, and the preheating temperature of the composite spinneret 7 is the same as the casting solution temperature.

[0044] Step 3: Maintain an air gap of 15mm.

[0045] Step 4: Coagulation bath phase separation. After initial phase separation in the air, the casting solution and core solution enter the coagulation bath for further phase separation to form the nascent hollow fiber membrane. The coagulation bath consists of non-solvent water at a temperature of 10°C.

[0046] Step 5: Immerse the nascent hollow fiber membrane in tap water to wash away the organic solvent. Soak the resulting hollow fiber ultrafiltration membrane in 40% glycerol for 12 hours. After soaking, dry it at room temperature.

[0047] The hollow fiber membrane was found to have a porosity of 75%, a flux of 860 LMH / bar, and a pore size of 20 nm, which falls within the scope of ultrafiltration.

[0048] Production and usage method 2:

[0049] Step 1: Prepare casting solution, core solution and functional solution.

[0050] The casting solution comprises 18 wt.% polyethersulfone (PES), 76 wt.% solvent mixture, and additives. The solvent mixture is N-methyl-2-pyrrolidone (NMP) / tetrahydrofuran in a mass ratio of 8:2. The additives include 4.5 wt.% ethylene glycol and 1.5 wt.% lithium chloride.

[0051] The core fluid is water.

[0052] The functional fluid comprises 20 wt.% sulfonated polyethersulfone (SPES), 10 wt.% ethylene glycol monomethyl ether (EGME), and 70 wt.% N-methyl-2-pyrrolidone (NMP).

[0053] Step 2: Spinning, with a spinning speed of 1.5–2.0 ml / min and a core liquid flow rate of 1.5–2.0 ml / min.

[0054] Casting solution, core solution, and functional solution are simultaneously ejected from the composite spinneret 7. The inner functional liquid layer 14 is the core solution, the casting solution layer 15 is the casting solution, and the outer functional liquid layer 16 is the functional solution. The spinning temperature is 60℃, the core solution temperature is 60℃, and the functional solution temperature is 5℃. The preheating temperature of the composite spinneret 7 is the same as the casting solution temperature.

[0055] Step 3: Maintain an air gap of 50mm and an ambient relative humidity of 85%.

[0056] Step 4: Coagulation bath phase separation. After initial phase separation with air, the casting solution, core solution, and functional solution enter the coagulation bath for further phase separation to form a hollow fiber membrane. The coagulation bath consists of non-solvent water at a temperature of 10°C.

[0057] The hollow fiber membrane was found to have a flux of 26 MH / bar, a pore size of 1.5 nm, and a Na2SO4 rejection rate of 87.8%, which falls within the category of nanofiltration.

[0058] Production and usage method 3:

[0059] Step 1: Prepare casting solution, core solution and functional solution.

[0060] The casting solution comprises 20 parts polyvinylidene fluoride (PVDF), 30 parts hydrophilic additive, and 50 parts organic solvent DMAc. The hydrophilic additive is prepared by mixing PVPk85 and PEG400 in a 1:3 ratio. The core solution comprises 40 parts DMAc and 60 parts water; the functional solution is pure alcohol.

[0061] Step 2: Spinning. The casting solution, core solution, and functional solution are simultaneously ejected from the composite spinneret 7. The inner functional liquid layer 14 is the core solution, the casting solution layer 15 is the casting solution, and the outer functional liquid layer 16 is the functional layer. The spinning temperature is 60°C, the core solution temperature is 60°C, the functional solution temperature is 5°C, and the preheating temperature of the composite spinneret 7 is the same as the casting solution temperature.

[0062] Step 3: Keep the air gap at 0mm.

[0063] Step 4: Coagulation bath phase separation. After initial phase separation with air, the casting solution and core solution enter the coagulation bath for further phase separation to form the nascent hollow fiber membrane. The coagulation bath is prepared with water and alcohol in a 9:1 ratio and the temperature is 0℃.

[0064] Step 5: Immerse the nascent hollow fiber membrane in tap water to wash away the organic solvent. Soak the resulting hollow fiber membrane in 40% glycerol for 24 hours, and then dry it at room temperature.

[0065] The hollow fiber membrane was tested and found to have a porosity of 80%, a flux of 1260 LMH / bar, and a pore size of 22 nm, which falls within the category of ultrafiltration.

[0066] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0067] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0068] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multifunctional hollow fiber membrane spinning apparatus, characterized by: The spinning solution supply unit (1), the composite spinneret (7), the crosslinking device (6), the phase inversion tank (3) and the spinning wheel (4) are included. The spinning solution supply unit (1) is connected with the composite spinneret (7), the outlet of the composite spinneret (7) faces the crosslinking device (6), the phase inversion tank (3) is arranged below the crosslinking device (6), and the spinning wheel (4) is arranged on one side of the phase inversion tank (3). The spinning solution supply unit (1) includes a casting solution kettle, a core liquid kettle and a multifunction kettle, the composite spinneret (7) is provided with a plurality of mutually independent extrusion channels, and each extrusion channel is connected with the casting solution kettle, the core liquid kettle and the multifunction kettle.

2. The multi-functional hollow fiber membrane spinning apparatus according to claim 1, characterized by: The composite spinneret (7) is provided with three circles of extrusion channels, the extrusion channels are respectively an inner layer functional liquid layer (14), a casting solution layer (15) and an outer layer functional liquid layer (16) from inside to outside, the inner layer functional liquid layer (14) is connected with the core liquid kettle, the outer layer functional liquid layer (16) is connected with the multifunction kettle, and the casting solution layer (15) is connected with the casting solution kettle.

3. The multi-functional hollow fiber membrane spinning apparatus according to claim 2, characterized by: A micro-flow pump is arranged between the outer layer functional liquid layer (16) and the tank body.

4. The multi-functional hollow fiber membrane spinning apparatus according to claim 2, characterized by: The inner layer functional liquid layer (14), the casting solution layer (15) and the outer layer functional liquid layer (16) are all arc structures.

5. The multi-functional hollow fiber membrane spinning apparatus according to claim 1, characterized by: A first reversing wheel (2) is arranged at the bottom of the phase inversion tank (3) near one side of the crosslinking device (6).

6. The multi-functional hollow fiber membrane spinning apparatus according to claim 1, characterized by: A second reversing wheel (5) is arranged at the top of the phase inversion tank (3) away from one side of the crosslinking device (6).

7. The multi-functional hollow fiber membrane spinning apparatus according to claim 1, characterized by: A tension controller is connected to the spinning wheel (4).

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