N-methylpyrrolidone recovery apparatus based on wastewater treatment and recovery method thereof

Abstract

The application discloses a kind of N-methyl pyrrolidone recovery equipment and recovery method based on wastewater treatment, belong to waste recovery field, the device includes settling tank, the top of the settling tank is provided with expansion port, the opening of the top of the expansion port is provided with filter assembly, the inside of the settling tank is provided with water liquid buffer assembly, the bottom of the settling tank is provided with sludge discharge port, the sidewall of the settling tank is provided with distillation mechanism, the distillation mechanism includes the heating tank on the sidewall of the settling tank.The application is used, the waste water is heated to ninety degrees Celsius by electric heating rod, the water in water liquid will evaporate quickly and push out from the surrounding pipe and vertical pipe, steam is condensed by condensing tower, water tank is used to receive material below the condensing tower, after moisture separation is completed, the temperature of electric heating rod is raised to two hundred degrees Celsius, N-methyl pyrrolidone starts to gasify, reagent tank is used to receive material below the condensing tower, the effect of efficient separation and recovery is realized.

Description

Technical Field

[0001] This invention relates to the field of waste recycling, and in particular to an N-methylpyrrolidone recycling device and method based on wastewater treatment. Background Technology

[0002] With the development of industrial technology, modern waste recycling technology has become increasingly sophisticated. N-methylpyrrolidone is used in coatings, solvents, and cleaning agents. However, N-methylpyrrolidone mixed in cleaning agents is discarded after use. If these discarded cleaning agents are directly discharged into nature, they will cause environmental pollution. Furthermore, N-methylpyrrolidone is toxic to humans and animals. Therefore, it is necessary to separate and recycle N-methylpyrrolidone from cleaning agents.

[0003] Previous recovery methods first required separating N-methylpyrrolidone from other solvents. Many N-methylpyrrolidone separation methods are based on the chemical and physical properties of N-methylpyrrolidone. N-methylpyrrolidone has a boiling point of 202 degrees Celsius and is not easily volatile. Water has a boiling point of 100 degrees Celsius. This physical property can be used to separate N-methylpyrrolidone from cleaning agents.

[0004] However, this separation method still has many uncertainties. For example, there is a lot of mud and sand in the solution. Secondly, N-methylpyrrolidone will leak air during distillation, which will lead to imperfections in the distillation process. Summary of the Invention

[0005] The purpose of this invention is to provide an N-methylpyrrolidone recovery device and method based on wastewater treatment. In operation, the heating rod is energized to heat the wastewater to 90 degrees Celsius. The water in the liquid rapidly evaporates and is pushed out through the surrounding pipe and vertical pipe. The vapor is condensed in a condenser tower, and collected in a water tank below the condenser tower. After the water separation is complete, the temperature of the heating rod is raised to 200 degrees Celsius. At this point, the N-methylpyrrolidone begins to vaporize. The vaporized N-methylpyrrolidone is once again pushed out through the surrounding pipe and vertical pipe. The N-methylpyrrolidone vapor is condensed in the condenser tower, and collected in a reagent tank below the condenser tower. This achieves efficient separation and recovery, thus solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an N-methylpyrrolidone recovery device based on wastewater treatment, comprising a settling tank, an expansion port at the top of the settling tank, a filter assembly at the opening at the top of the expansion port, a water buffer assembly inside the settling tank, a sludge discharge port at the bottom of the settling tank, and a distillation mechanism on the side wall of the settling tank. The distillation mechanism includes a heating box mounted on the side wall of the settling tank, the heating box being fixedly connected to the side wall of the settling tank by reinforcing ribs. The bottom is connected to the chamber inside the settling tank via a shut-off valve. The heating tank is equipped with a heating assembly, which includes an electric heating rod on the inner side wall of the heating tank. The top of the heating tank is equipped with a cover, and the top of the cover is connected to a circumferential pipe. A condensing tower is also installed on the side wall of the settling tank. The condensing tower is fixed on a vertical support. A vertical pipe is also installed at the end of the circumferential pipe. The vertical pipe passes through the bottom opening of the condensing tower and the top opening of the vertical pipe extends to the top of the condensing tower. A receiving box is installed below the bottom opening of the condensing tower.

[0007] Furthermore, the outer side of the condenser is provided with an annular array of fins, and the condenser and fins are made of copper.

[0008] Furthermore, the filter assembly includes a mesh bag with an opening at the top of the expansion port. The mesh bag is made of sheet metal stamped to a thickness of one millimeter. The flanges at both ends of the mesh bag overlap the left and right edges of the expansion port. The mesh bag is provided with a number of rectangular arrays of round openings. A layer of filter assembly is laid on the top of the mesh bag.

[0009] Furthermore, the filter assembly includes two sets of torque flaps at the left and right ends of the expansion port. A feeding roller is rotatably arranged in the torque flap at the left end, and a winding roller is rotatably arranged in the torque flap at the right end. The winding roller is mounted on the output shaft of the winding motor. The filter cloth is pulled out from the feeding roller and connected to the winding roller. A pressure roller is rotatably arranged at the top of the filter cloth, and the filter cloth passes through the gap between the pressure roller and the mesh bag.

[0010] Furthermore, the water buffer assembly includes a buffer module in a settling tank. The upper and lower ends of the buffer module are provided with conical chambers, and the cavities of the conical chambers are connected through fine holes. Each conical chamber is provided with a filling cone, and a thin rod is detachably provided in the middle of the filling cone. The thin rod is inserted into the inside of the fine holes. The surfaces of the filling cone and the thin rod are provided with annular arrays of water passage grooves.

[0011] Furthermore, the upper and lower ends of the thin rod are provided with square blocks, and the cone ends of the two filling cones are provided with square holes that match the square blocks. The square holes and the square blocks are fixedly connected by bolts.

[0012] Furthermore, the sludge discharge port is equipped with a disassembly door inside, and two pull handles are provided on the side wall of the disassembly door. The edge of the disassembly door is connected to the sludge discharge port by a sealing strip.

[0013] Furthermore, the vertical support includes two supports on the side wall of the settling tank. The outer end of the support is provided with a collar that matches the condensing tower. The collar consists of two separable semi-rings. The inner end of the support is provided with an assembly plate that is fixedly connected to the side wall of the settling tank.

[0014] Furthermore, the receiving box is divided into a water tank and a reagent tank, which can be aligned with the opening at the bottom of the condensing tower in turn, and the side wall of the vertical pipe and the inner side wall of the condensing tower are not stuck together.

[0015] Furthermore, the following steps are included:

[0016] S1. Wastewater containing N-methylpyrrolidone is fed into the expansion port from the top. The filter cloth will filter out the mud and sand in the wastewater. After the filter cloth filters out a certain amount of mud and sand, the winding motor drives the winding roller to rotate. At this time, the winding roller pulls the filter cloth to move a unit distance. A new section of filter cloth will be rearranged on the top of the net bag, and the filter cloth full of mud and sand will be wound onto the winding roller.

[0017] S2. After filtration, the wastewater flows to the top of the buffer module. The wastewater then flows through the gaps in the water tank. When the wastewater flows to the bottom of the buffer module, it will flow down the wall and be stored at the bottom of the settling tank. Fine silt will settle at the bottom of the settling tank. The wastewater flowing down the wall will not stir up the settled silt again, which facilitates the separation of fine silt and wastewater.

[0018] S3. When the liquid level inside the settling tank rises, the shut-off valve is open. The liquid level inside the heating tank is equal to that inside the settling tank. After a certain amount of water is stored inside the heating tank, the shut-off valve is closed. At this time, the electric heating rod is energized to heat the wastewater to 90 degrees Celsius. The water in the liquid will evaporate rapidly and be pushed out from the surrounding pipe and the vertical pipe. The steam is condensed down through the condenser tower and collected in the water tank below the condenser tower. After the water is completely removed, the temperature of the electric heating rod is raised to 200 degrees Celsius. At this time, N-methylpyrrolidone begins to vaporize. The vaporized N-methylpyrrolidone is once again pushed out from the surrounding pipe and the vertical pipe. The vapor of N-methylpyrrolidone is condensed down through the condenser tower and collected in the reagent tank below the condenser tower.

[0019] In summary, due to the adoption of the above-mentioned technologies, the beneficial effects of this invention are:

[0020] Firstly, the electric heating rod heats the wastewater to 90 degrees Celsius, causing the water in the liquid to evaporate rapidly and be pushed out through the surrounding pipe and vertical pipe. The steam is condensed down through the condenser tower, and the material is collected in a water tank at the bottom of the condenser tower. After the water separation is complete, the temperature of the electric heating rod is raised to 200 degrees Celsius. At this time, N-methylpyrrolidone begins to vaporize. The vaporized N-methylpyrrolidone is once again pushed out through the surrounding pipe and vertical pipe. The vapor of N-methylpyrrolidone is condensed down through the condenser tower, and the material is collected in a reagent tank at the bottom of the condenser tower, achieving a highly efficient separation and recovery effect.

[0021] Secondly, wastewater containing N-methylpyrrolidone is fed into the expansion port from the top. The filter cloth will filter out the mud and sand in the wastewater. After the filter cloth filters out a certain amount of mud and sand, the winding motor drives it to rotate. At this time, the traction filter cloth moves a unit distance, and a new section of filter cloth will be rearranged at the top of the net bag. The filter cloth full of mud and sand will be pulled up. The filtered wastewater flows to the top of the buffer module. The wastewater then flows through the gaps in the water passage. When the wastewater flows to the bottom of the buffer module, it will hang down the wall and be stored at the bottom of the settling tank. Fine mud and sand will settle at the bottom of the settling tank. The wastewater flowing down the wall will not stir up the settled mud and sand again, which facilitates the separation of fine mud and sand from the wastewater. Attached Figure Description

[0022] Figure 1 This is a frontal schematic diagram of an N-methylpyrrolidone recovery device and its recovery method based on wastewater treatment.

[0023] Figure 2 This is a side view schematic diagram of an N-methylpyrrolidone recovery device and recovery method based on wastewater treatment.

[0024] Figure 3 This is a schematic diagram of a pressure roller in an N-methylpyrrolidone recovery device and recovery method based on wastewater treatment.

[0025] Figure 4 This is a schematic cross-sectional view of an N-methylpyrrolidone recovery device and recovery method based on wastewater treatment.

[0026] Figure 5 This is a schematic diagram of a buffer module for an N-methylpyrrolidone recovery device and method based on wastewater treatment.

[0027] Figure 6 This is a schematic cross-sectional view of the buffer module of an N-methylpyrrolidone recovery device and recovery method based on wastewater treatment.

[0028] Figure 7 This is a schematic diagram of a condenser tower used in an N-methylpyrrolidone recovery device and recovery method based on wastewater treatment.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Settling box; 2. Expansion port; 201. Torque flipper; 202. Discharge roller; 203. Rewinding roller; 204. Rewinding motor; 205. Net bag; 3. Filter cloth; 4. Pressure roller; 5. Heating box; 501. Reinforcing rib; 502. Shut-off valve; 503. Cover; 504. Circulating pipe; 505. Vertical pipe; 6. Condensing tower; 7. Disassembly door; 701. Pull handle; 8. Buffer module; 801. Conical chamber; 802. Fine hole; 803. Filling cone; 804. Water trough; 9. Heating rod; 10. Support frame. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides, for example Figures 1-7The N-methylpyrrolidone recovery device based on wastewater treatment shown includes a settling tank 1. An expansion port 2 is provided at the top of the settling tank 1, and a filter assembly is installed at the opening at the top of the expansion port 2. A water buffer assembly is installed inside the settling tank 1, and a sludge discharge port is provided at the bottom of the settling tank 1. A distillation mechanism is installed on the side wall of the settling tank 1. The distillation mechanism includes a heating box 5 installed on the side wall of the settling tank 1. The heating box 5 is fixedly connected to the side wall of the settling tank 1 by reinforcing ribs 501. The bottom of the heating box 5 is connected to the internal chamber of the settling box 1 via a shut-off valve 502. The heating box 5 is equipped with a heating assembly, including an electric heating rod 9 on the inner wall of the heating box 5. A cover 503 is installed at the top of the heating box 5, and a spiral tube 504 is connected to the top of the cover 503. A condensing tower 6 is also installed on the side wall of the settling box 1, and the condensing tower 6 is fixed to a vertical support. A vertical pipe 505 is also installed at the end of the spiral tube 504, and the vertical pipe 505 passes through the bottom opening of the condensing tower 6. The top opening of pipe 505 extends to the top of condenser tower 6. A receiving box is installed below the bottom opening of condenser tower 6. Wastewater containing N-methylpyrrolidone is fed into the condenser tower 6 through the top of expansion port 2. When the liquid level inside settling tank 1 rises, shut-off valve 502 is open. The liquid level inside heating tank 5 is equal to the liquid level inside settling tank 1. After a certain amount of water is stored inside heating tank 5, shut-off valve 502 is closed. At this time, electric heating rod 9 is energized to heat the wastewater to 90 degrees Celsius, and the water in the wastewater will evaporate rapidly. The steam is pushed out through the surrounding pipe 504 and the vertical pipe 505, and then condensed in the condenser tower 6. After the water is completely removed, the temperature of the heating rod 9 is raised to 200 degrees Celsius. At this time, N-methylpyrrolidone begins to vaporize. The vapor of N-methylpyrrolidone is condensed in the condenser tower 6. N-methylpyrrolidone has a boiling point greater than 200 degrees Celsius and is not easily volatile, while water has a boiling point of 100 degrees Celsius and is easily volatile. By utilizing this physical property, high-purity N-methylpyrrolidone material can be recovered and extracted by distilling through two heating stages.

[0033] The outer side of the condenser 6 is provided with an annular array of fins. The condenser 6 and the fins are made of metallic copper. The distillation temperature in both steps is above 90 degrees Celsius. The temperature difference between 90 degrees Celsius and room temperature is relatively large. Therefore, the condenser 6 can exchange heat and condense at room temperature. The copper fins have higher heat dissipation efficiency.

[0034] The filter assembly includes a mesh bag 205 with an opening at the top of the expansion port 2. The mesh bag 205 is made of sheet metal stamped to a thickness of one millimeter. The flanges at both ends of the mesh bag 205 overlap the left and right edges of the expansion port 2. The mesh bag 205 is provided with a number of rectangular arrays of round openings. A layer of filter assembly is laid on the top of the mesh bag 205. The mesh bag 205 provides support for the filter assembly, which can be attached to the mesh bag 205 in an arc shape to facilitate the pouring of waste liquid.

[0035] The filter assembly includes two sets of torque flaps 201 at the left and right ends of the expansion port 2. A feeding roller 202 is rotatably arranged in the torque flap 201 at the left end, and a winding roller 203 is rotatably arranged in the torque flap 201 at the right end. The winding roller 203 is mounted on the output shaft of the winding motor 204. The filter cloth 3 is pulled out from the feeding roller 202 and connected to the winding roller 203. A pressure roller 4 is rotatably arranged at the top of the filter cloth 3. The filter cloth 3 passes through the gap between the pressure roller 4 and the net bag 205. Wastewater containing N-methylpyrrolidone is fed into the expansion port 2 from the top. The filter cloth 3 will filter out the mud and sand in the wastewater. After the filter cloth 3 filters out a certain amount of mud and sand, the winding motor 204 drives 203 to rotate. At this time, 203 pulls the filter cloth 3 to move a unit distance. A new section of filter cloth 3 will be rearranged at the top of the net bag 205, and the filter cloth 3 full of mud and sand will be gathered onto 203.

[0036] The water buffer assembly includes a buffer module 8 in the settling tank 1. The upper and lower ends of the buffer module 8 are provided with conical chambers 801. The cavities of the conical chambers 801 are connected through fine holes 802. Each conical chamber 801 is provided with a filling cone 803. A thin rod is detachably provided in the middle of the filling cone 803. The thin rod passes through the inside of the fine holes 802. The surfaces of the filling cone 803 and the thin rod are provided with annular array water passage channels 804. After filtration, the wastewater flows to the top of the buffer module 8. The wastewater then flows through the gaps in the water passage channels 804. When the wastewater flows to the bottom of the buffer module 8, it hangs down the wall and is stored at the bottom of the settling tank 1. Fine silt settles at the bottom of the settling tank 1. The wastewater flowing down the wall will not stir up the settled silt again, which facilitates the separation of fine silt and wastewater.

[0037] The thin rod has square blocks at both ends, and the cone ends of the two filling cones 803 are provided with square holes that match the square blocks. The square holes and the square blocks are fixedly connected by bolts. The two filling cones 803 and the thin rod can be disassembled. The staff regularly disassembles the filling cones 803 to clean up debris and prevent the water tank 804 from being blocked.

[0038] The sludge discharge port is equipped with a disassembly door 7 inside. Two pull handles 701 are provided on the side wall of the disassembly door 7. The edge of the disassembly door 7 is connected to the sludge discharge port through a sealing strip. After the fine mud and sand that settles at the bottom of the settling tank 1 in the wastewater accumulate to a certain extent, the disassembly door 7 is opened periodically to remove the fine mud and sand.

[0039] The vertical support includes two supports 10 on the side wall of the settling tank 1. The outer end of the support 10 is provided with a collar that matches the condensing tower 6. The collar consists of two separable half-rings. The inner end of the support 10 is provided with an assembly plate that is fixedly connected to the side wall of the settling tank 1. The position of the condensing tower 6 is fixed by the support 10. When the position of the condensing tower 6 needs to be adjusted, the assembly plate at the inner end of the support 10 is removed and replaced with a new one.

[0040] The receiving box is divided into a water tank and a reagent tank. The water tank and the reagent tank can be aligned with the opening at the bottom of the condenser tower 6 in turn. The side wall of the vertical pipe 505 and the inner side wall of the condenser tower 6 are not stuck together. The distillation is divided into two steps. In the first step, when condensing water, the water tank is used to receive the material. In the second step, when condensing N-methylpyrrolidone, the reagent tank is used to receive the material. Thus, both the water and N-methylpyrrolidone are collected.

[0041] Includes the following steps:

[0042] S1. Wastewater containing N-methylpyrrolidone is fed into the expansion port 2 from the top. The filter cloth 3 will filter out the mud and sand in the wastewater. After the filter cloth 3 filters out a certain amount of mud and sand, the winding motor 204 drives the winding roller 203 to rotate. At this time, the winding roller 203 pulls the filter cloth 3 to move a unit distance. A new section of filter cloth 3 will be rearranged at the top of the net bag 205, and the filter cloth 3 full of mud and sand will be wound onto the winding roller 203.

[0043] S2. After filtration, the wastewater flows to the top of the buffer module 8. The wastewater then flows through the gap in the water tank 804. When the wastewater flows to the bottom of the buffer module 8, it will flow down the wall and be stored at the bottom of the settling tank 1. Fine silt will settle at the bottom of the settling tank 1. The wastewater flowing down the wall will not stir up the settled silt again, which facilitates the separation of fine silt and wastewater.

[0044] S3. When the liquid level inside the settling tank 1 rises, the shut-off valve 502 is open. The liquid level inside the heating tank 5 is equal to the liquid level inside the settling tank 1. After a certain amount of water is stored inside the heating tank 5, the shut-off valve 502 is closed. At this time, the electric heating rod 9 is energized to heat the wastewater to 90 degrees Celsius. The water in the liquid will evaporate rapidly and be pushed out from the surrounding pipe 504 and the vertical pipe 505. The steam is condensed down through the condensing tower 6 and collected in the water tank below the condensing tower 6. After the water is completely removed, the temperature of the electric heating rod 9 is raised to 200 degrees Celsius. At this time, N-methylpyrrolidone begins to vaporize. The vaporized N-methylpyrrolidone is pushed out again from the surrounding pipe 504 and the vertical pipe 505. The vapor of N-methylpyrrolidone is condensed down through the condensing tower 6 and collected in the reagent tank below the condensing tower 6.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0046] 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.

Claims

1. An N-methylpyrrolidone recovery device based on wastewater treatment, characterized in that: The settling tank (1) includes an expansion port (2) at its top, a filter assembly at the opening of the expansion port (2), a water buffer assembly inside the settling tank (1), a sludge discharge port at the bottom of the settling tank (1), a distillation mechanism on the side wall of the settling tank (1), and a heating box (5) on the side wall of the settling tank (1). The heating box (5) is fixedly connected to the side wall of the settling tank (1) by reinforcing ribs (501). The bottom of the heating box (5) is connected to the internal chamber of the settling tank (1) by a shut-off valve (502). The settling tank (1) is equipped with a heating assembly, which includes an electric heating rod (9) on the inner wall of the heating box (5). The top of the heating box (5) is equipped with a cover (503), and the top of the cover (503) is connected to a circumferential pipe (504). A condensing tower (6) is also provided on the side wall of the settling tank (1). The condensing tower (6) is fixed on a vertical support. A vertical pipe (505) is also provided at the end of the circumferential pipe (504). The vertical pipe (505) is inserted into the bottom opening of the condensing tower (6). The top opening of the vertical pipe (505) extends to the top position of the condensing tower (6). A receiving box is provided below the bottom opening of the condensing tower (6).

2. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 1, characterized in that: The condenser (6) is provided with an annular array of fins on its outer side, and the condenser (6) and the fins are made of copper.

3. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 1, characterized in that: The sludge discharge port is provided with a disassembly door (7) inside. Two pull handles (701) are provided on the side wall of the disassembly door (7). The edge of the disassembly door (7) is connected to the sludge discharge port by a sealing strip.

4. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 1, characterized in that: The vertical support includes two supports (10) on the side wall of the settling tank (1). The outer end of the support (10) is provided with a collar that matches the condensing tower (6). The collar consists of two separable half rings. The inner end of the support (10) is provided with an assembly plate that is fixedly connected to the side wall of the settling tank (1).

5. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 1, characterized in that: The filter assembly includes a mesh bag (205) with an opening at the top of the expansion port (2). The mesh bag (205) is made of sheet metal stamping with a diameter of one millimeter. The flanges at both ends of the mesh bag (205) overlap the left and right edges of the expansion port (2). The mesh bag (205) is provided with a number of rectangular arrays of round openings. A layer of filter assembly is laid on the top of the mesh bag (205).

6. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 5, characterized in that: The filter assembly includes two sets of torque flaps (201) at the left and right ends of the expansion port (2). A feeding roller (202) is rotatably arranged in the torque flap (201) at the left end, and a winding roller (203) is rotatably arranged in the torque flap (201) at the right end. The winding roller (203) is mounted on the output shaft of the winding motor (204). The filter cloth (3) is pulled out from the feeding roller (202) and connected to the winding roller (203). A pressure roller (4) is rotatably arranged at the top of the filter cloth (3). The filter cloth (3) passes through the gap between the pressure roller (4) and the mesh bag (205).

7. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 6, characterized in that: The water buffer assembly includes a buffer module (8) in a settling tank (1). The upper and lower ends of the buffer module (8) are provided with conical chambers (801). The cavities of the conical chambers (801) are connected through a fine hole (802). The interior of each conical chamber (801) is provided with a filling cone (803). A thin rod is detachably provided in the middle of the filling cone (803). The thin rod is inserted into the interior of the fine hole (802). The surfaces of the filling cone (803) and the thin rod are provided with annular array water passages (804).

8. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 7, characterized in that: The thin rod has a block at both the top and bottom, and the cone ends of the two filling cones (803) are provided with square holes that match the blocks. The square holes and blocks are fixedly connected by bolts.

9. The N-methylpyrrolidone recovery device based on wastewater treatment according to claim 8, characterized in that: The receiving box is divided into a water tank and a reagent tank. The water tank and the reagent tank can be aligned with the opening at the bottom of the condensing tower (6) in turn. The side wall of the vertical pipe (505) and the inner side wall of the condensing tower (6) are not stuck together.

10. A recovery method based on the N-methylpyrrolidone recovery device according to claim 9, characterized in that, Includes the following steps: S1. Wastewater containing N-methylpyrrolidone is fed into the top of the expansion port (2). The filter cloth (3) will filter out the mud and sand in the wastewater. After the filter cloth (3) filters out a certain amount of mud and sand, the winding motor (204) drives the winding roller (203) to rotate. At this time, the winding roller (203) pulls the filter cloth (3) to move a unit distance. A new section of filter cloth (3) will be rearranged on the top of the net bag (205), and the filter cloth (3) full of mud and sand will be wound onto the winding roller (203). S2. After filtration, the wastewater flows to the top of the buffer module (8). The wastewater then flows through the gap in the water tank (804). When the wastewater flows to the bottom of the buffer module (8), it will flow down the wall and be stored at the bottom of the settling tank (1). Fine silt will settle at the bottom of the settling tank (1). The wastewater flowing down the wall will not stir up the silt at the bottom again, which facilitates the separation of fine silt and wastewater. S3. When the liquid level inside the settling tank (1) rises, the shut-off valve (502) is open. The liquid level inside the heating tank (5) is equal to the liquid level inside the settling tank (1). After storing a certain amount of water inside the heating tank (5), the shut-off valve (502) is closed. At this time, the electric heating rod (9) is energized to heat the wastewater to 90 degrees Celsius. The water in the liquid will evaporate rapidly and be pushed out from the surrounding pipe (504) and the vertical pipe (505). The steam is condensed down through the condensing tower (6). The material is collected in the water tank below the condensing tower (6). After the water is completely removed, the temperature of the electric heating rod (9) is raised to 200 degrees Celsius. At this time, N-methylpyrrolidone begins to vaporize. The vaporized N-methylpyrrolidone is pushed out again from the surrounding pipe (504) and the vertical pipe (505). The vapor of N-methylpyrrolidone is condensed down through the condensing tower (6) and the material is collected in the reagent tank below the condensing tower (6).

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