Chemical material liquid nanofiltration membrane separation device

Abstract

The utility model relates to chemical separation equipment technical field discloses a kind of chemical feed liquid nanofiltration membrane separation devices, including first bearing block, symmetrically arranged two groups of nanofiltration separation components, transfusion mechanism, effluent mechanism, gas transmission mechanism and heating exhaust mechanism;Two groups of nanofiltration separation components are interconnected by center cylinder, U-shaped tube is jointly fixed on its upper end, and constitute the circulating balance flow channel that penetrates two sides nanofiltration separation components;Transfusion mechanism is used to feed liquid to the inside of nanofiltration membrane tube, effluent mechanism is used to discharge the permeate after nanofiltration separation, gas transmission mechanism is used to send backblowing gas into center cylinder inner chamber, and heating exhaust mechanism is used to discharge waste gas after backblowing and heat.The utility model is through symmetric double-cylinder type nanofiltration structure cooperation controllable circulating flow channel, realizes the efficient crossflow separation of feed liquid, the automatic cyclic reprocessing of unseparated liquid and the in-situ air-flushing cleaning of nanofiltration membrane, with the advantages of high separation efficiency, membrane cleaning maintenance is convenient, equipment integration degree is high.

Description

Technical Field

[0001] This utility model relates to the field of chemical separation equipment technology, specifically a nanofiltration membrane separation device for chemical feed liquids. Background Technology

[0002] Nanofiltration is a pressure-driven membrane separation technology that falls between ultrafiltration and reverse osmosis. It is widely used in the concentration, desalination, and purification processes of feed solutions in chemical, pharmaceutical, and food processing industries. Currently, common nanofiltration devices mostly use single or multiple tubular or spiral wound membrane modules connected in series. The feed solution flows through the membrane surface under pump pressure. Solvents and small molecule solutes permeate through the membrane layer to form permeate, while large molecule solutes are retained to form concentrate.

[0003] However, existing nanofiltration separation devices have the following problems in practical applications: First, the separation efficiency of a single flow through the membrane tube is limited. For chemical liquids with high concentrations or difficult separation, if some of the unseparated liquid is discharged directly, it will result in waste of raw materials. If it is returned through an external circulation pipeline, it will increase the complexity of the pipeline and the equipment footprint. Second, the circulation channels of existing devices are mostly external, with many interfaces and complex sealing points, making installation and maintenance inconvenient. Third, nanofiltration membranes are prone to concentration polarization and membrane fouling during use, leading to a decrease in flux. Traditional cleaning methods require shutdown to disassemble the membrane element or use chemical cleaning, which is cumbersome and affects continuous production efficiency. Fourth, the waste gas or backwash waste liquid after cleaning lacks a smooth discharge channel and is prone to accumulate inside the device, affecting the cleaning effect and membrane life.

[0004] Therefore, how to design a nanofiltration membrane separation device that can achieve feed liquid recycling and separation in a limited space, has in-situ cleaning function, and has a high degree of structural integration has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0005] The purpose of this invention is to provide a nanofiltration membrane separation device for chemical liquids, which has the advantages of high separation efficiency, liquid circulation and re-separation function, in-situ air flushing cleaning function, and high structural integration, thus solving the problems in the prior art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A nanofiltration membrane separation device for chemical liquid includes a first support block, two support blocks symmetrically fixed to the upper end of the first support block, two fixed disks respectively fixed to the two support blocks at opposite ends, two fixed cylinders respectively fixed to the two fixed disks at opposite ends, and a connecting cylinder jointly fixed to the two fixed cylinders at opposite ends. It also includes two sets of nanofiltration separation components symmetrically arranged inside the fixed cylinders and the connecting cylinder, a liquid outlet mechanism arranged at the lower end of the fixed cylinder, a liquid delivery mechanism arranged on one side wall of the first support block, a gas delivery mechanism arranged on the other side wall of the first support block, a heating and exhaust mechanism arranged at the upper end of the connecting cylinder, and a controller electrically connected to each valve body and electrical component.

[0008] One end of the nanofiltration separation component is fixed to the fixed disk, and the two nanofiltration separation components are interconnected through the central cylinder. The upper ends of the two nanofiltration separation components are fixed to a U-shaped tube. The inner wall of the connecting cylinder is flush with the inner wall of the fixed cylinder.

[0009] Preferably, the nanofiltration separation assembly includes a fixed tube that is fixedly connected to the center of the fixed plate near the center of the connecting cylinder, a connecting tube fixed to the upper end of the fixed tube, a nanofiltration membrane tube fixed to the center of the fixed tube near the center of the connecting cylinder, and a hollow inner cylinder fixed to the inner wall of the nanofiltration membrane tube; a first valve body is provided on the fixed tube, a second valve body is provided on the connecting tube, a U-shaped tube is fixedly connected to the upper ends of the two connecting tubes, and the two inner cylinders are respectively fixedly connected to the two ends of the central cylinder at their close proximity ends.

[0010] Preferably, the nanofiltration membrane tube is a composite tube consisting of a support layer, a transition layer and a separation layer from the inside out. The inner wall of the support layer is fixedly attached to the outer peripheral wall of the inner cylinder, and a liquid passage gap is reserved between the outer peripheral wall of the nanofiltration membrane tube and the inner wall of the fixed cylinder.

[0011] It is worth noting that the nanofiltration membrane tube adopts a multi-layer composite structure. The support layer provides mechanical strength, the transition layer realizes pore size transition, and the separation layer achieves precise nanofiltration separation. The inner cylinder and the central cylinder are fixedly connected to form a continuous internal flow channel, allowing the feed liquid to flow axially between the two sets of nanofiltration separation components. The liquid passage gap between the fixed cylinder and the nanofiltration membrane tube provides space for the permeate to collect and be discharged.

[0012] Preferably, the liquid dispensing mechanism includes a liquid dispensing pipe that is fixedly connected to the lower end of the fixed cylinder and a third valve body disposed on the liquid dispensing pipe, wherein the liquid inlet end of the liquid dispensing pipe is connected to the internal cavity of the fixed cylinder.

[0013] Preferably, the infusion mechanism includes a second support block fixed to the side wall of the first support block, a water pump fixed to the upper end of the second support block, a pumping pipe fixed to the pumping end, and an outlet pipe fixed to the pumping end. The outlet end of the outlet pipe passes through the outer wall of the fixed cylinder and extends into its internal cavity.

[0014] Preferably, the gas delivery mechanism includes a third bearing block fixed to the side wall of the first bearing block, an air pump fixed to the upper end of the third bearing block, a connecting pipe fixed to the air outlet end of the air pump, a bend pipe communicating with the air outlet end of the connecting pipe, and a riser pipe fixed to the other end of the bend pipe. The lower end of the riser pipe passes through the upper end of the central cylinder and extends into the inner wall cavity of the central cylinder.

[0015] It is worth noting that the gas delivery mechanism sends compressed gas from the central cylinder to the inner cavity of the nanofiltration membrane tubes on both sides through the riser, forming a reverse pulse airflow, which can effectively peel off the pollutants attached to the inner wall of the membrane tube, realize in-situ air flushing cleaning, and eliminate the need to disassemble the membrane module, which greatly reduces maintenance costs and downtime.

[0016] Preferably, the heating and exhaust mechanism includes a straight pipe that is fixed to the upper end of the connecting cylinder and multiple heating units fixed to the inner wall of the straight pipe. Each heating unit includes a fixing ring fixed to the inner wall of the straight pipe and an air heating ring fixed to the inner wall of the fixing ring.

[0017] Preferably, the U-shaped tube, two connecting tubes, and two fixed tubes together form a balanced flow channel that runs through the inner cavity of the nanofiltration membrane tube on both sides.

[0018] It is worth noting that when the device is in the circulation separation mode, the first valve body on one side is closed. After the feed liquid is separated by the nanofiltration membrane tube on one side, the impurity liquid enters the inner tube on the other side through the central cylinder, and then flows back to the fixed tube on this side through the fixed tube on the other side, the connecting tube on this side, the U-shaped tube, and the connecting tube on this side, and re-enters the nanofiltration membrane tube for secondary separation. This balanced flow channel realizes the automatic circulation of the feed liquid between the two sets of nanofiltration separation components, replacing the traditional external pipeline circulation method, effectively improving the separation efficiency, and making the equipment structure more compact.

[0019] Preferably, the axes of the central cylinder, inner cylinder, nanofiltration membrane tube, and fixed tube coincide with each other, and the internal cavity of the central cylinder communicates with the internal cavity of the nanofiltration membrane tube through the internal cavity of the inner cylinder.

[0020] Preferably, there is a gap between the outer peripheral wall of the riser and the inner wall of the straight pipe, forming a smooth upward channel for the backflushing gas, which facilitates the discharge of the exhaust gas carrying impurities after backflushing through the inner cavity of the connecting cylinder and the annular gap between the straight pipe and the riser.

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0022] 1. This utility model solves the problems of existing nanofiltration devices requiring external pipelines for liquid circulation and having a dispersed structure by using two symmetrically arranged nanofiltration separation components and a balanced flow channel formed by a U-shaped tube. By controlling the valve body to switch between separation mode and circulation-reseparation mode, it realizes efficient cross-flow separation of liquid and automatic return and reprocessing of unseparated liquid, thereby improving separation efficiency and raw material utilization.

[0023] 2. This utility model solves the problem of existing nanofiltration devices requiring shutdown and disassembly for membrane cleaning by cooperating with the gas delivery mechanism and the central cylinder. The air pump sends compressed gas to the central cylinder and the inner cylinders on both sides through the riser, forming a reverse pulse airflow to perform in-situ air flushing cleaning of the nanofiltration membrane tube. In conjunction with the heating and exhaust mechanism, the gas in the system is slightly heated and the escaped moisture is assisted in being discharged, which effectively extends the service life of the membrane and reduces maintenance costs.

[0024] 3. This utility model integrates the infusion mechanism, liquid outlet mechanism, gas delivery mechanism and heating exhaust mechanism on the same load-bearing structure, resulting in a compact overall structure and convenient installation. The controller enables centralized control of each valve body and pump body to achieve automated switching of separation, circulation and cleaning modes, making it suitable for continuous nanofiltration separation of chemical liquids. Attached Figure Description

[0025] Figure 1 The diagram shown is a three-dimensional structural schematic of this utility model;

[0026] Figure 2 The diagram shown is a three-dimensional structural schematic of the infusion mechanism of this utility model;

[0027] Figure 3 The diagram shown is a three-dimensional structural schematic of the gas delivery mechanism of this utility model.

[0028] Figure 4 The diagram shown is a three-dimensional cross-sectional view of the nanofiltration membrane tube of this utility model.

[0029] Figure 5 The diagram shown is a cross-sectional view of this utility model.

[0030] Figure 6 The diagram shown is a three-dimensional cross-sectional view of the present invention.

[0031] Reference numerals: 1. First support block; 2. Support block; 3. Fixing disc; 4. Fixing cylinder; 5. Fixing pipe; 6. First valve body; 7. Connecting pipe; 8. U-shaped pipe; 9. Second valve body; 10. Controller; 11. Second support block; 12. Water pump; 13. Pumping pipe; 14. Outlet pipe; 15. Third support block; 16. Air pump; 17. Connecting pipe; 18. Riser; 19. Bend; 20. Liquid outlet pipe; 21. Third valve body; 22. Nanofiltration membrane tube; 221. Support layer; 222. Transition layer; 223. Separation layer; 23. Connecting cylinder; 24. Inner cylinder; 25. Central cylinder; 26. Straight pipe; 27. Fixing ring; 28. Air heating ring. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. 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.

[0033] To address the limitations of existing nanofiltration technologies, such as limited separation efficiency, the need for external piping for feed circulation, inconvenient membrane cleaning and maintenance, and low structural integration, the following technical solution is proposed. Please refer to [link / reference]. Figures 1 to 6 ;

[0034] A nanofiltration membrane separation device for chemical liquid includes a first support block 1, two support blocks 2 symmetrically fixed to the upper end of the first support block 1, two fixed disks 3 respectively fixed to the two support blocks 2 at opposite ends, two fixed cylinders 4 respectively fixed to the two fixed disks 3 at opposite ends, and a connecting cylinder 23 jointly fixed to the two fixed cylinders 4 at opposite ends. It also includes two sets of nanofiltration separation components symmetrically arranged inside the fixed cylinders 4 and the connecting cylinder 23, a liquid outlet mechanism located at the lower end of the fixed cylinder 4, a liquid delivery mechanism located on one side wall of the first support block 1, a gas delivery mechanism located on the other side wall of the first support block 1, a heating and exhaust mechanism located at the upper end of the connecting cylinder 23, and a controller 10 electrically connected to each valve body and electrical component. One end of each nanofiltration separation component is fixed to the fixed disk 3, and the two sets of nanofiltration separation components are interconnected through a central cylinder 25. A U-shaped tube 8 is jointly fixed to the upper end of both sets of nanofiltration separation components. The inner wall of the connecting cylinder 23 is flush with the inner wall of the fixed cylinder 4.

[0035] In this embodiment, specifically, the nanofiltration separation assembly includes a fixed tube 5 that is fixedly connected to the center of the fixed plate 3 near the center of the connecting cylinder 23, a connecting tube 7 fixedly connected to the upper end of the fixed tube 5, a nanofiltration membrane tube 22 fixedly connected to the center of the fixed tube 5 near the center of the connecting cylinder 23, and a hollow inner cylinder 24 fixedly connected to the inner wall of the nanofiltration membrane tube 22. A first valve body 6 is provided on the fixed tube 5, and a second valve body 9 is provided on the connecting tube 7. A U-shaped tube 8 is fixedly connected to the upper ends of both connecting tubes 7. The two inner cylinders 24 are respectively fixedly connected to the two ends of the central cylinder 25 at their respective close ends. The first valve body 6 is used to control the opening and closing of the fixed tube 5, and the second valve body 9 is used to control the opening and closing of the connecting tube 7. The U-shaped tube 8 connects the upper ends of the two connecting tubes 7.

[0036] In this embodiment, specifically, the nanofiltration membrane tube 22 is a composite tube consisting of a support layer 221, a transition layer 222, and a separation layer 223, arranged sequentially from the inside out. The support layer 221 is a rigid porous structure with a certain pore size, providing overall mechanical strength; the transition layer 222 achieves a gradual transition in pore size; the separation layer 223 is a selective separation layer with nanoscale pore size, enabling precise separation of components with different molecular weights in the feed solution. The inner wall of the support layer 221 is fixedly attached to the outer peripheral wall of the inner cylinder 24, and a liquid-passing gap is reserved between the outer peripheral wall of the nanofiltration membrane tube 22 and the inner wall of the fixed cylinder 4. This liquid-passing gap is used to collect the permeate that passes through the nanofiltration membrane tube 22.

[0037] In this embodiment, specifically, the liquid discharge mechanism includes a liquid discharge pipe 20 that is fixedly connected to the lower end of the fixed cylinder 4 and a third valve body 21 disposed on the liquid discharge pipe 20. The liquid inlet end of the liquid discharge pipe 20 is in communication with the internal cavity of the fixed cylinder 4. When the third valve body 21 is opened, the permeate is discharged and collected through the liquid discharge pipe 20.

[0038] In this embodiment, specifically, the infusion mechanism includes a second support block 11 fixed to the side wall of the first support block 1, a water pump 12 fixed to the upper end of the second support block 11, a water pump pipe 13 fixed to the water pump 12's pumping end, and a water outlet pipe 14 fixed to the water pump 12's outlet end. The outlet end of the water outlet pipe 14 passes through the outer wall of the fixed cylinder 4 and extends into its internal cavity, for sending the liquid to be separated into the inner cavity of the nanofiltration membrane tube 22.

[0039] In this embodiment, specifically, the gas delivery mechanism includes a third support block 15 fixed to the side wall of the first support block 1, an air pump 16 fixed to the upper end of the third support block 15, a connecting pipe 17 fixed to the outlet end of the air pump 16, a bend 19 communicating with the outlet end of the connecting pipe 17, and a riser 18 fixed to the other end of the bend 19. The lower end of the riser 18 passes through the upper end of the central cylinder 25 and extends into the inner wall cavity of the central cylinder 25. The compressed gas generated by the air pump 16 is sent into the inner cavity of the central cylinder 25 through the connecting pipe 17, the bend 19, and the riser 18, and then diffuses into the inner cavities of the inner cylinders 24 on both sides and the nanofiltration membrane tube 22, forming a reverse pulse airflow to perform in-situ cleaning of the inner wall of the membrane.

[0040] In this embodiment, specifically, the heating and exhaust mechanism includes a straight pipe 26 that is fixedly connected to the upper end of the connecting cylinder 23, and multiple heating units fixedly connected to the inner wall of the straight pipe 26. Each heating unit includes a fixing ring 27 fixedly connected to the inner wall of the straight pipe 26 and an air heating ring 28 fixedly connected to the inner wall of the fixing ring 27. The air heating ring 28 is used to heat the passing airflow and prevent the cleaning exhaust gas from condensing during the discharge process.

[0041] In this embodiment, specifically, the U-shaped tube 8, the two connecting tubes 7, and the two fixed tubes 5 together form a balanced flow channel that runs through the inner cavity of the nanofiltration membrane tubes 22 on both sides, which is used to realize the reflux of the feed liquid between the two sets of nanofiltration separation components in the circulation separation mode.

[0042] In this embodiment, specifically, the axes of the central cylinder 25, the inner cylinder 24, the nanofiltration membrane tube 22, and the fixed tube 5 coincide with each other. The internal cavity of the central cylinder 25 communicates with the internal cavity of the nanofiltration membrane tube 22 through the internal cavity of the inner cylinder 24, forming an axially penetrating material flow channel.

[0043] In this embodiment, specifically, there is a gap between the outer peripheral wall of the riser 18 and the inner wall of the straight pipe 26, which serves as an upward discharge channel for the backflushing gas.

[0044] Working principle: During use, the controller 10 controls the working status of each valve body and pump body. The device has the following working modes:

[0045] Normal separation mode: Open both first valve bodies 6 and close both second valve bodies 9. The liquid to be separated is continuously fed into the fixed tube 5 on one side through the external feed pipeline. The liquid enters the inner cavity of the nanofiltration membrane tube 22 through the fixed tube 5. Under the drive of the feed pressure, the solvent and small molecule solutes permeate through the separation layer 223 of the nanofiltration membrane tube 22 and enter the liquid-passing gap between the fixed cylinder 4 and the nanofiltration membrane tube 22. The collected permeate is discharged and collected through the outlet pipe 20. The retentate that does not permeate enters the inner cavity of the nanofiltration membrane tube 22 on the other side through the inner cylinder 24, the central cylinder 25, and the other inner cylinder 24 to continue separation. Finally, the concentrated liquid is discharged from the other fixed tube 5.

[0046] Recirculation and re-separation mode: When it is necessary to improve the separation efficiency, the first valve body 6 on one side of the fixed pipe 5 is closed, the second valve body 9 on the two connecting pipes 7 is opened, and the first valve body 6 on the other side of the fixed pipe 5 remains open. The feed liquid is continuously fed from the other side of the fixed pipe 5. After the initial separation through the nanofiltration membrane tube 22, the unpermeated liquid is pushed through the inner cylinder 24 and the central cylinder 25 to the inner cylinder 24 and the inner cavity of the nanofiltration membrane tube 22 on this side. Since the first valve body 6 on this side is closed, the feed liquid cannot be discharged from the fixed pipe 5 on this side. Instead, it goes up through the connecting pipe 7 on this side into the U-shaped tube 8, and then flows back to the other side of the fixed pipe 5 through the connecting pipe 7 on the other side, and re-enters the inner cavity of the nanofiltration membrane tube 22 for secondary separation. In this way, the feed liquid continues to flow in the closed loop formed by the fixed pipe 5, the nanofiltration membrane tube 22, the inner cylinder 24, the central cylinder 25, the connecting pipe 7 and the U-shaped tube 8. The continuous flow makes the feed liquid that was not fully separated in the first time repeatedly flow over the membrane surface for multiple separations, which effectively improves the separation effect.

[0047] Cleaning mode: After the separation operation is completed, the nanofiltration membrane tube 22 is cleaned. The controller 10 controls the closure of the first valve body 6 and the second valve body 9, and opens the third valve body 21. The water pump 12 of the infusion mechanism is started, and the external flushing liquid is sent through the pumping pipe 13 and the outlet pipe 14 into the liquid passage between the fixed cylinder 4 and the nanofiltration membrane tube 22 to flush the outer wall of the nanofiltration membrane tube 22. The flushing liquid carries the impurities that adhered to the outer wall of the membrane and the liquid passage during the separation process and is discharged through the outlet pipe 20. At the same time, the air pump 16 of the gas delivery mechanism is started, and the compressed gas is sent through the riser pipe 18 into the inner cavity of the central cylinder 25 and then enters the inner cylinders 24 on both sides and the inner cavity of the nanofiltration membrane tube 22 in the opposite direction, forming an impact airflow from the inside to the outside of the membrane tube, which peels off the residual pollutants adhering to the inner wall of the nanofiltration membrane tube 22. During this process, the air heating ring 28 of the heating exhaust mechanism is started simultaneously to slightly heat the gas in the system to reduce the adhesion of pollutants on the membrane surface and enhance the peeling effect. The peeled pollutants are driven by the air-pressure differential and discharged directionally through the outlet pipe 20 along with the flushing liquid and the airflow, forming the main discharge path. Meanwhile, the heating and exhaust mechanism at the upper end of the connecting cylinder 23 continues to work, using the annular gap between the straight pipe 26 and the riser pipe 18 to smoothly discharge a small amount of humid and hot gas that may escape into the inner cavity of the connecting cylinder 23 during the cleaning process, and to prevent water vapor from condensing in the pipeline, thus playing the role of auxiliary exhaust and anti-condensation.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0049] 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.

Claims

1. A nanofiltration membrane separation device for chemical liquid feed, characterized in that, It includes a first support block (1), two support blocks (2) symmetrically fixed to the upper end of the first support block (1), two fixed plates (3) respectively fixed to the two support blocks (2) at opposite ends, two fixed cylinders (4) respectively fixed to the two fixed plates (3) at opposite ends, and a connecting cylinder (23) jointly fixed to the two fixed cylinders (4) at opposite ends. It also includes two sets of nanofiltration separation components symmetrically arranged inside the fixed cylinders (4) and the connecting cylinder (23), a liquid outlet mechanism arranged at the lower end of the fixed cylinder (4), a liquid delivery mechanism arranged on one side wall of the first support block (1), a gas delivery mechanism arranged on the other side wall of the first support block (1), a heating and exhaust mechanism arranged at the upper end of the connecting cylinder (23), and a controller (10) electrically connected to each valve body and electrical component. One end of the nanofiltration separation component is fixed to the fixed disk (3), and the two nanofiltration separation components are connected to each other through the central cylinder (25). The upper ends of the two nanofiltration separation components are fixed to a U-shaped tube (8); the inner wall of the connecting cylinder (23) is flush with the inner wall of the fixed cylinder (4).

2. The nanofiltration membrane separation device for chemical feed liquids according to claim 1, characterized in that, The nanofiltration separation assembly includes a fixed tube (5) that is fixed to the center of the fixed plate (3) near the center of the connecting cylinder (23), a connecting tube (7) fixed to the upper end of the fixed tube (5), a nanofiltration membrane tube (22) fixed to the center of the fixed tube (5) near the center of the connecting cylinder (23), and a hollow inner cylinder (24) fixed to the inner wall of the nanofiltration membrane tube (22). The fixed tube (5) is provided with a first valve body (6), the connecting tube (7) is provided with a second valve body (9), the upper ends of the two connecting tubes (7) are fixed with a U-shaped tube (8), and the two inner cylinders (24) are fixed to the two ends of the center cylinder (25) respectively.

3. The nanofiltration membrane separation device for chemical feed liquids according to claim 2, characterized in that, The nanofiltration membrane tube (22) is a composite tube consisting of a support layer (221), a transition layer (222) and a separation layer (223) from the inside out. The inner wall of the support layer (221) is fixedly attached to the outer peripheral wall of the inner cylinder (24), and a liquid passage gap is reserved between the outer peripheral wall of the nanofiltration membrane tube (22) and the inner wall of the fixed cylinder (4).

4. The nanofiltration membrane separation device for chemical feed liquids according to claim 1, characterized in that, The liquid discharge mechanism includes a liquid discharge pipe (20) that is fixed to the lower end of the fixed cylinder (4) and a third valve body (21) that is set on the liquid discharge pipe (20). The liquid inlet end of the liquid discharge pipe (20) is connected to the internal cavity of the fixed cylinder (4).

5. The nanofiltration membrane separation device for chemical feed liquids according to claim 1, characterized in that, The infusion mechanism includes a second support block (11) fixed to the side wall of the first support block (1), a water pump (12) fixed to the upper end of the second support block (11), a water pump pipe (13) fixed to the water pump (12) pumping end, and a water outlet pipe (14) fixed to the water pump (12) outlet end. The outlet end of the water outlet pipe (14) passes through the outer wall of the fixed cylinder (4) and extends into its internal cavity.

6. The nanofiltration membrane separation device for chemical feed liquids according to claim 1, characterized in that, The gas delivery mechanism includes a third support block (15) fixed to the side wall of the first support block (1), an air pump (16) fixed to the upper end of the third support block (15), a connecting pipe (17) fixed to the air outlet end of the air pump (16), a bend (19) connected to the air outlet end of the connecting pipe (17), and a riser (18) fixed to the other end of the bend (19). The lower end of the riser (18) passes through the upper end of the central cylinder (25) and extends into the inner wall cavity of the central cylinder (25).

7. The nanofiltration membrane separation device for chemical feed liquids according to claim 1, characterized in that, The heating and exhaust mechanism includes a straight pipe (26) that is fixed to the upper end of the connecting cylinder (23) and multiple heating units that are fixed to the inner wall of the straight pipe (26). Each heating unit includes a fixing ring (27) fixed to the inner wall of the straight pipe (26) and an air heating ring (28) fixed to the inner wall of the fixing ring (27).

8. A nanofiltration membrane separation device for chemical feed liquids according to claim 2, characterized in that, The U-shaped tube (8), two connecting tubes (7) and two fixed tubes (5) together form a balanced flow channel that runs through the inner cavity of the nanofiltration membrane tube (22) on both sides.

9. A nanofiltration membrane separation device for chemical feed liquids according to claim 2, characterized in that, The axes of the central cylinder (25), inner cylinder (24), nanofiltration membrane tube (22) and fixed tube (5) coincide with each other. The internal cavity of the central cylinder (25) communicates with the internal cavity of the nanofiltration membrane tube (22) through the internal cavity of the inner cylinder (24).

10. A nanofiltration membrane separation device for chemical feed liquids according to claim 7, characterized in that, There is a gap between the outer wall of the riser (18) and the inner wall of the straight pipe (26).

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