A recovery mechanism for N-methylpyrrolidone

Abstract

The application discloses a recovery mechanism for N-methylpyrrolidone, and relates to the field of waste gas recovery, which comprises a recovery tower body, an air inlet main pipe is arranged at the lower part of the recovery tower body, air inlet branch pipes are arranged on the outer wall of the air inlet main pipe at equal intervals, air inlet nozzles are uniformly arranged on the outer surfaces of the air inlet main pipe and the air inlet branch pipes, a uniform spraying structure is arranged at the upper part of the recovery tower body, the uniform spraying structure comprises a rotating disc which is rotatably arranged on the inner wall of the recovery tower body, the outer wall of the rotating disc is provided with spraying pipes which are arranged at equal angles, the bottom of each spraying pipe is provided with spraying heads which are arranged at equal intervals, and a knocking structure is arranged at the bottom of the filler layer, so that the recovery waste gas and the spraying liquid can be uniformly contacted. The recovery mechanism for N-methylpyrrolidone is cooperatively matched with the air inlet structure, the uniform spraying structure and the knocking structure, so that the N-methylpyrrolidone-containing waste gas can be efficiently recovered, resource waste can be reduced, and environmental pollutant emission can be reduced.

Description

Technical Field

[0001] This invention relates to the field of waste gas recovery technology, specifically to a recovery mechanism for N-methylpyrrolidone. Background Technology

[0002] In the production process of lithium-ion batteries, the positive electrode coating process generates a large amount of process waste gas containing N-methylpyrrolidone. As a high-value organic solvent, direct emission of N-methylpyrrolidone not only wastes resources but also pollutes the environment. In addition, it has certain volatility and potential safety risks, so it needs to be recycled and treated before reuse.

[0003] In the prior art, Chinese Patent No. CN211302137U discloses a special tail gas absorption device for the recovery of N-methylpyrrolidone, including a tail gas recovery box, a gas transmission pipe, and a tail gas absorption tower. The tail gas recovery box is provided with an upper collection chamber and a lower collection chamber. Rotating seats are rotatably connected to opposite sides of the upper and lower collection chambers. A condenser pipe is connected between the two rotating seats. A cooling fan is provided on the side wall of the tail gas recovery box, facing the condenser pipe. A water tank is provided at the bottom of the tail gas recovery box, and a circulation pipe is provided on the side wall of the tail gas recovery box. A first circulation pump is provided on the circulation pipe. One end of the circulation pipe is connected to the water tank, and the other end enters the tail gas recovery box and is provided with a first spray pipe. The first spray pipe is provided with nozzles. The water sprayed through the nozzles cools the condenser pipe. At the same time, with the action of the cooling fan, the water on the condenser pipe evaporates and absorbs heat, thereby effectively cooling the tail gas in the condenser pipe.

[0004] For example, in the prior art, Chinese Patent No. CN213643675U discloses a special odor treatment system for N-methylpyrrolidone recovery, including a sealed collection hood, a first air inlet pipe, a second air inlet pipe, a mixing box, and a purification tower. The bottom of the inner cavity of the purification tower is provided with a hydrolysis acidification tank, and an air intake pipe is provided in the hydrolysis acidification tank. The air intake pipe leads the gas in the first air supply pipe to the hydrolysis acidification tank. A ceramic packing layer is provided above the hydrolysis acidification tank, and a spray pipe is provided above the ceramic packing layer. One end of the spray pipe penetrates the side wall of the purification tower and is connected to a water pump. The water inlet end of the water pump is connected to an inlet pipe, which is connected to the hydrolysis acidification tank at the bottom of the purification tower. A microbial packing layer is provided above the spray pipe, and an activated carbon filter layer is provided above the microbial packing layer. Waste odor molecules are introduced into the hydrolysis acidification tank through the air intake pipe for mixing, so that the odor molecules are hydrolyzed and acidified. Then, the waste odor molecules are deodorized by the microbial membrane on the biological packing layer.

[0005] Based on the above information, existing recycling mechanisms have limited contact time and area between the spray liquid and the recycled waste gas when recovering waste gas containing N-methylpyrrolidone, resulting in low recovery efficiency of N-methylpyrrolidone. Therefore, we propose a recycling mechanism for N-methylpyrrolidone. Summary of the Invention

[0006] The purpose of this invention is to provide a recovery mechanism for N-methylpyrrolidone, in order to solve the problem mentioned in the background art that the existing recovery mechanisms have limited contact time and contact area between the spray liquid and the recovered waste gas when recovering waste gas containing N-methylpyrrolidone, resulting in low recovery efficiency of N-methylpyrrolidone.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a recovery mechanism for N-methylpyrrolidone, comprising a recovery tower body, a drain outlet at the bottom of the recovery tower body, an exhaust outlet at the top of the recovery tower body, a packing layer inside the recovery tower body, a main air inlet pipe at the lower part of the recovery tower body, and air inlet branch pipes evenly distributed on the outer wall of the main air inlet pipe, air inlet nozzles uniformly distributed on the outer surface of the main air inlet pipe and the air inlet branch pipes, a uniform spraying structure at the upper part of the recovery tower body, the uniform spraying structure comprising a rotating disk rotatably mounted on the inner wall of the recovery tower body, spray pipes evenly distributed on the outer wall of the rotating disk, and spray nozzles evenly distributed at the bottom of the spray pipes, and a knocking structure at the bottom of the packing layer, for achieving uniform contact between the recovered waste gas and the spray liquid, and preventing dead zones of stagnation of the recovered waste gas.

[0008] Preferably, the packing layer is located between the main air inlet pipe and the uniform spray structure, and the packing layer is close to the uniform spray structure. The outer wall of the recovery tower is provided with a liquid inlet pipe, and the liquid inlet pipe is connected to a liquid inlet pump.

[0009] Preferably, the uniform spraying structure further includes a cavity disposed between the rotating disk and the inner wall of the recovery tower, and the inner wall of the cavity is provided with a drive baffle. The cavity is connected to the liquid inlet pipe, and the spray pipe is connected to the cavity.

[0010] Preferably, the drive baffles are distributed at equal angles on the inner wall of the cavity, and the drive baffles are designed to be inclined as a whole.

[0011] Preferably, the striking structure includes a rotating shaft fixedly installed at the center of the rotating disk, a piston sleeve on the outer wall of the rotating shaft, a sliding rod slidably installed at the end of the piston sleeve, and a striking block at the end of the sliding rod. The inner wall of the recovery tower is provided with an extrusion inclined block, and the bottom of the packing layer is provided with a flange.

[0012] Preferably, the bottom end of the rotating shaft is rotatably connected to the bottom of the recovery tower body, the piston sleeves are distributed at equal angles on the outer wall of the rotating shaft, and the length of the piston sleeves is less than the radius of the packing layer. The outer wall of the slide rod is fitted with a compression spring, one end of the compression spring abuts against the outer wall of the striking block, and the other end of the compression spring abuts against the end of the piston sleeve.

[0013] Preferably, the flange is designed as an annular plate, and the length of the flange is less than the distance between the bottom of the filler layer and the slide rod. When the striking block is in the striking state, the outer wall of the striking block is in contact with the inner wall of the flange. The extrusion inclined block has a trapezoidal cross-section, and the extrusion inclined block and the slide rod are arranged in a one-to-one correspondence. In the non-striking state, the outer wall of the extrusion inclined block abuts against the end of the slide rod.

[0014] Preferably, the striking structure further includes a first one-way hole and a second one-way hole formed on the outer wall of the piston sleeve, and the end of the slide rod is provided with a piston block that is slidably connected to the inner wall of the piston sleeve.

[0015] Preferably, the first one-way hole and the second one-way hole are symmetrically distributed, and both the first one-way hole and the second one-way hole are connected to the internal cavity of the piston sleeve. The first one-way hole is used to recover waste gas entering the piston sleeve, and the outlet end of the second one-way hole faces the bottom of the packing layer.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This N-methylpyrrolidone recovery mechanism, through the coordinated operation of the air intake structure, uniform spray structure, and knocking structure, forms a highly efficient and stable N-methylpyrrolidone recovery system. It solves the problems of uneven contact and short contact time between waste gas and spray liquid in existing technologies, and avoids the problem of reduced recovery efficiency caused by packing layer blockage. While achieving efficient recovery of N-methylpyrrolidone-containing waste gas, it reduces resource waste and environmental pollutant emissions. Moreover, the mechanism is stable in operation and easy to maintain.

[0017] 2. By setting a main air inlet pipe at the bottom of the recovery tower and setting equally spaced air inlet branch pipes on the outer wall of the main air inlet pipe, and uniformly setting air inlet nozzles on the outer surface of the main air inlet pipe and the air inlet branch pipes, the waste gas containing N-methylpyrrolidone can be evenly dispersed into the interior of the recovery tower. Compared with the problem of uneven distribution caused by the centralized introduction of waste gas in the existing technology, this multi-branch pipe and multi-nozzle air inlet structure can significantly increase the initial contact range between the waste gas and the subsequent spray liquid and packing layer, laying the foundation for improving the recovery efficiency.

[0018] 3. By setting up a uniform spray structure consisting of a rotating disk, spray pipe, spray head, cavity, and drive baffle, when the spray liquid is delivered to the cavity through the inlet pipe, the spray liquid impacts the inclined drive baffle, which drives the rotating disk to rotate. This allows the spray head on the spray pipe to achieve 360° rotation spraying, enabling the spray liquid to form a uniform liquid distribution layer in the packing layer. This ensures that the spray liquid and the rising exhaust gas achieve all-round, dead-angle-free contact, significantly extending the contact time between the two and effectively improving the absorption efficiency of N-methylpyrrolidone.

[0019] 4. By setting a striking structure at the bottom of the packing layer, the rotating disk drives the rotating shaft to rotate, so that the sliding rod on the piston sleeve interacts with the extrusion inclined block and works in conjunction with the extrusion spring to achieve reciprocating motion. This causes the striking block to periodically strike the flange at the bottom of the packing layer, which can effectively prevent the packing material in the packing layer from solidifying and clogging due to long-term use. It ensures that the packing material is always in a loose and uniform contact state, ensuring that the exhaust gas can pass through the packing layer smoothly. At the same time, it maintains a good contact area between the packing material and the exhaust gas and spray liquid, avoiding a decrease in recovery efficiency.

[0020] 5. The first and second one-way holes on the outer wall of the piston sleeve in the striking structure, together with the piston block at the end of the slide rod, allow the exhaust gas from the lower part of the recovery tower to be drawn into the piston sleeve through the first one-way hole during the reciprocating motion of the slide rod, and then sprayed out towards the bottom of the packing layer through the second one-way hole. This not only enhances the gas flow velocity near the packing layer and promotes the full mixing and contact of the exhaust gas with the spray liquid and packing, but also disturbs the gas in the bottom area of ​​the packing layer, further reducing the dead zone of gas stagnation and improving the overall recovery effect. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of the recovery tower body of the present invention; Figure 3 This is a schematic diagram of the internal structure of the recovery tower of the present invention; Figure 4 This is a schematic diagram of the rotating disk, cavity, drive baffle, spray pipe and spray head of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the rotating disk of the present invention; Figure 6 This is a schematic diagram of the striking structure and uniform spraying structure of the present invention; Figure 7 For the present invention Figure 6 Enlarged structural diagram at point A in the middle; Figure 8 This is a schematic diagram of the striking structure of the present invention; Figure 9 For the present invention Figure 8 Enlarged structural diagram at point B; Figure 10 This is a schematic diagram of the cross-sectional structure of the piston sleeve of the present invention.

[0022] In the diagram: 1. Recovery tower body; 2. Main air inlet pipe; 3. Branch air inlet pipe; 4. Air inlet nozzle; 5. Drain outlet; 6. Exhaust outlet; 7. Packing layer; 8. Liquid inlet pipe; 9. Rotating disc; 10. Cavity; 11. Spray pipe; 12. Spray head; 13. Drive baffle; 14. Rotating shaft; 15. Flange; 16. Piston sleeve; 17. Sliding rod; 18. Piston block; 19. Striking block; 20. Compression spring; 21. First one-way hole; 22. Second one-way hole; 23. Compression inclined block. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: Please refer to Figures 1-10 The present invention provides the following technical solution: a recovery mechanism for N-methylpyrrolidone, comprising a recovery tower body 1, a drain port 5 at the bottom of the recovery tower body 1, an exhaust port 6 at the top of the recovery tower body 1, a packing layer 7 inside the recovery tower body 1, an air inlet main pipe 2 at the lower part of the recovery tower body 1, and air inlet branch pipes 3 evenly distributed on the outer wall of the air inlet main pipe 2, air inlet nozzles 4 uniformly distributed on the outer surface of the air inlet main pipe 2 and the air inlet branch pipes 3, and a uniform spraying structure at the upper part of the recovery tower body 1, the uniform spraying structure comprising a rotating disk 9 rotatably installed on the inner wall of the recovery tower body 1, and spray pipes 11 evenly distributed on the outer wall of the rotating disk 9, and spray nozzles 12 evenly distributed at the bottom of the spray pipes 11; the packing layer 7 is located between the air inlet main pipe 2 and the uniform spraying structure, and the packing layer 7 is close to the uniform spraying structure; an inlet pipe 8 is provided on the outer wall of the recovery tower body 1, and an inlet pump is connected to the inlet pipe 8.

[0025] like Figures 2-7 As shown, the uniform spraying structure also includes a cavity 10 disposed between the rotating disk 9 and the inner wall of the recovery tower 1, and a drive baffle 13 is provided on the inner wall of the cavity 10. The cavity 10 is connected to the liquid inlet pipe 8, and the spray pipe 11 is connected to the cavity 10. The drive baffle 13 is distributed at equal angles on the inner wall of the cavity 10, and the drive baffle 13 is designed to be inclined.

[0026] When recovering waste gas containing N-methylpyrrolidone, the waste gas first enters through the main inlet pipe 2 at the bottom of the recovery tower 1. After being diverted by the equally spaced inlet branch pipes 3 on the outer wall of the main inlet pipe 2, the waste gas is sprayed into the interior of the recovery tower 1 in a dispersed manner by the inlet nozzles 4 evenly arranged on the surface of the branch pipes and the main inlet pipe 2, laying a uniform gas distribution foundation for subsequent gas-liquid contact. At the same time, the inlet pipe 8 of the external liquid pump delivers the spray liquid to the cavity 10 of the uniform spray structure at the top of the recovery tower 1. Since the inner wall of the cavity 10 is provided with inclined drive baffles 13 distributed at equal angles, the spray liquid will impact the inclined drive baffles 13 when flowing in the cavity 10, generating a force in the circumferential direction. The rotating disk 9 connected to the cavity 10 rotates around the central axis of the recovery tower 1. The spray pipes 11, which are distributed at equal angles on the outer wall of the rotating disk 9, rotate synchronously with the rotating disk 9. The spray heads 12, which are evenly arranged at the bottom of the spray pipes 11, achieve 360° rotation spraying, so that the spray liquid forms a liquid layer with a wide coverage and uniform distribution in the recovery tower 1. The rising dispersed waste gas and the spray liquid sprayed by the rotating spray fully converge in the packing layer 7, which greatly increases the gas-liquid contact area and contact time, thereby efficiently absorbing N-methylpyrrolidone in the waste gas. The absorbed spray liquid is discharged and recovered through the drain port 5 at the bottom of the recovery tower 1. The gas that is not completely absorbed moves to the top of the recovery tower 1 and is finally discharged from the exhaust port 6.

[0027] Example 2: In conventional methods, the packing layer inside the recovery tower is static during operation, which can easily lead to clumping, solidification, or blockage of the packing material due to long-term use, thereby affecting the waste gas recovery efficiency. Therefore, this example discloses the following: Figures 6-10 As shown, the bottom of the packing layer 7 is provided with a striking structure to achieve uniform contact between the recovered waste gas and the spray liquid, and to prevent the recovered waste gas from having dead corners. The striking structure includes a rotating shaft 14 fixedly installed at the center of the rotating disk 9, and a piston sleeve 16 is provided on the outer wall of the rotating shaft 14. A sliding rod 17 is slidably installed at the end of the piston sleeve 16, and a striking block 19 is provided at the end of the sliding rod 17. The inner wall of the recovery tower body 1 is provided with a squeezing inclined block 23, and the bottom of the packing layer 7 is provided with a flange 15.

[0028] like Figures 6-10As shown, the bottom end of the rotating shaft 14 is rotatably connected to the bottom of the recovery tower 1. The piston sleeve 16 is distributed at equal angles on the outer wall of the rotating shaft 14, and the length of the piston sleeve 16 is less than the radius of the packing layer 7. The outer wall of the slide rod 17 is fitted with a compression spring 20, and one end of the compression spring 20 abuts against the outer wall of the striking block 19, and the other end of the compression spring 20 abuts against the end of the piston sleeve 16. The flange 15 is designed as an annular plate, and the length of the flange 15 is less than the distance between the bottom of the packing layer 7 and the slide rod 17. When the striking block 19 is in the striking state, the outer wall of the striking block 19 is in contact with the inner wall of the flange 15. The cross section of the compression inclined block 23 is designed as a trapezoid, and the compression inclined block 23 is set one-to-one with the slide rod 17. When not striking, the outer wall of the compression inclined block 23 abuts against the end of the slide rod 17.

[0029] When the rotating disk 9 rotates under the impact of the spray liquid, the rotating shaft 14, which is fixedly installed at the center of the rotating disk 9, rotates synchronously with the rotating disk 9. The piston sleeves 16, which are evenly distributed on the outer wall of the rotating shaft 14, move in a circular motion around the rotating shaft 14. During the circular motion, the sliding rod 17, which is slidably installed at the end of the piston sleeve 16, will continuously contact the squeezing inclined block 23 fixedly installed on the inner wall of the recovery tower 1. In the non-impact state, the end of the sliding rod 17 is always in contact with the outer wall of the squeezing inclined block 23. Since the cross-section of the squeezing inclined block 23 is trapezoidal, as the piston sleeve 16 rotates, the sliding rod 17 will be subjected to an inward squeezing force along the axial direction of the piston sleeve 16 when it contacts the inclined surface of the squeezing inclined block 23. This causes the sliding rod 17 to slide into the piston sleeve 16 and compress the squeezing spring 20 sleeved on the outer wall of the sliding rod 17. At this time, the squeezing spring 20 is in storage. In the active state, when the slide rod 17 rotates with the piston sleeve 16 to the position where it is disengaged from the compression inclined block 23, the elastic potential energy of the compression spring 20 is released, pushing the slide rod 17 to extend rapidly outward along the axial direction of the piston sleeve 16. The striking block 19 at the end of the slide rod 17 then collides with the annular plate-shaped flange 15 at the bottom of the packing layer 7, generating a striking force. As the rotating shaft 14 continues to rotate, the slide rod 17 repeatedly performs cyclic actions, periodically striking the flange 15. The striking force is transmitted through the flange 15 to the filling material inside the packing layer 7, which can effectively prevent the filling material from clumping, solidifying, or blocking due to long-term use, ensuring that the filling material is always in a loose state, ensuring that the exhaust gas can pass smoothly through the packing layer 7, and maintaining good contact between the filling material and the exhaust gas and spray liquid, avoiding a decrease in recovery efficiency due to blockage of the packing layer 7.

[0030] Example 3: In conventional methods, the waste gas below the packing layer comes into directional contact with the packing layer, resulting in certain gas stagnation dead zones, which affects the gas-liquid mixing effect and reduces the recovery efficiency. Therefore, this example discloses the following: Figures 8-10As shown, the striking structure also includes a first one-way hole 21 and a second one-way hole 22 opened on the outer wall of the piston sleeve 16. The end of the slide rod 17 is provided with a piston block 18 that is slidably connected to the inner wall of the piston sleeve 16. The first one-way hole 21 and the second one-way hole 22 are symmetrically distributed, and both the first one-way hole 21 and the second one-way hole 22 are connected to the internal cavity of the piston sleeve 16. The first one-way hole 21 is used to recover the waste gas entering the piston sleeve 16, and the outlet end of the second one-way hole 22 faces the bottom of the packing layer 7.

[0031] When the slide rod 17 slides into the piston sleeve 16 under the action of the squeezing inclined block 23, the piston block 18, which is slidably connected to the inner wall of the piston sleeve 16 at the end of the slide rod 17, moves into the piston sleeve 16 simultaneously, causing the volume of the internal chamber of the piston sleeve 16 to decrease and the pressure to increase. Since the first one-way hole 21 only allows gas to enter the piston sleeve 16 from the lower part of the recovery tower body 1, the first one-way hole 21 is closed at this time; while the second one-way hole 22 allows gas to be ejected from the inside of the piston sleeve 16 to the bottom of the packing layer 7. Under the action of the chamber pressure, the original gas in the piston sleeve 16 is ejected towards the bottom of the packing layer 7 through the second one-way hole 22, forming a directional airflow, which disturbs the gas in the bottom area of ​​the packing layer 7 and promotes the mixing of the waste gas and the spray liquid in this area. When the slide rod 17 slides into the piston sleeve 16, the piston block 18, which is slidably connected to the inner wall of the piston sleeve 16, moves into the piston sleeve 16 simultaneously, causing the volume of the internal chamber of the piston sleeve 16 to decrease and the pressure to increase. Since the first one-way hole 21 only allows gas to enter the piston sleeve 16 from the lower part of the recovery tower body 1, the first one-way hole 21 is closed at this time; while the second one-way hole 22 allows gas to be ejected from the inside of the piston sleeve 16 to the bottom of the packing layer 7. Under the action of the chamber pressure, the gas in the piston sleeve 16 is ejected towards the bottom of the packing layer 7 through the second one-way hole 22, forming a directional airflow, which disturbs the gas in the bottom area of ​​the packing layer 7 and promotes the mixing of the waste gas and the spray liquid in this area. When the piston block 18 extends outward from the piston sleeve 16 under the action of the compression spring 20, it moves outward synchronously with the slide rod 17, increasing the volume and reducing the pressure of the internal chamber of the piston sleeve 16. At this time, the second one-way hole 22 closes, and the waste gas in the lower part of the recovery tower 1 enters the piston sleeve 16 through the first one-way hole 21 under the action of pressure difference, completing the gas intake. With the reciprocating motion of the slide rod 17, the first one-way hole 21 and the second one-way hole 22 alternately realize the cycle of intake and discharge, continuously transporting the waste gas in the lower part of the recovery tower 1 to the bottom of the packing layer 7 and forming disturbance. This not only enhances the gas flow velocity near the packing layer 7, but also further reduces the dead zone of gas stagnation, improves the mixing and contact effect of waste gas with spray liquid and packing, and helps to improve the overall recovery efficiency.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A recovery mechanism for N-methylpyrrolidone, comprising a recovery tower (1), wherein the bottom of the recovery tower (1) is provided with a drain port (5) and the top of the recovery tower (1) is provided with an exhaust port (6), and the interior of the recovery tower (1) is provided with a packing layer (7), characterized in that: The lower part of the recovery tower (1) is provided with an air inlet main pipe (2), and the outer wall of the air inlet main pipe (2) is provided with air inlet branch pipes (3) distributed at equal intervals. The outer surfaces of the air inlet main pipe (2) and the air inlet branch pipes (3) are uniformly provided with air inlet nozzles (4). The upper part of the recovery tower (1) is provided with a uniform spray structure. The uniform spray structure includes a rotating disk (9) rotatably installed on the inner wall of the recovery tower (1), and the outer wall of the rotating disk (9) is provided with spray pipes (11) distributed at equal angles. The bottom of the spray pipes (11) is provided with spray nozzles (12) evenly distributed. The bottom of the packing layer (7) is provided with a knocking structure to achieve uniform contact between the recovered waste gas and the spray liquid and prevent the recovered waste gas from having dead corners. The striking structure includes a rotating shaft (14) fixedly installed at the center of the rotating disk (9), and a piston sleeve (16) is provided on the outer wall of the rotating shaft (14), and a sliding rod (17) is slidably installed at the end of the piston sleeve (16), and a striking block (19) is provided at the end of the sliding rod (17). The inner wall of the recovery tower (1) is provided with a squeezing inclined block (23), and the bottom of the packing layer (7) is provided with a flange (15). The striking structure also includes a first one-way hole (21) and a second one-way hole (22) opened on the outer wall of the piston sleeve (16), and the end of the slide rod (17) is provided with a piston block (18) that is slidably connected to the inner wall of the piston sleeve (16). The first one-way hole (21) and the second one-way hole (22) are symmetrically distributed, and both the first one-way hole (21) and the second one-way hole (22) are connected to the internal cavity of the piston sleeve (16). The first one-way hole (21) is used to recover waste gas entering the piston sleeve (16), and the outlet end of the second one-way hole (22) faces the bottom of the packing layer (7). The uniform spray structure also includes a cavity (10) between the rotating disk (9) and the inner wall of the recovery tower (1), and the inner wall of the cavity (10) is provided with a drive baffle (13). The cavity (10) is connected to the liquid inlet pipe (8), and the spray pipe (11) is connected to the cavity (10). The drive baffles (13) are distributed at equal angles on the inner wall of the cavity (10), and the drive baffles (13) are designed to be inclined.

2. The recovery mechanism for N-methylpyrrolidone according to claim 1, characterized in that: The packing layer (7) is located between the main air inlet pipe (2) and the uniform spray structure, and the packing layer (7) is close to the uniform spray structure. The outer wall of the recovery tower (1) is provided with a liquid inlet pipe (8), and the liquid inlet pipe (8) is connected to a liquid inlet pump.

3. The recovery mechanism for N-methylpyrrolidone according to claim 1, characterized in that: The bottom end of the rotating shaft (14) is rotatably connected to the bottom of the recovery tower (1). The piston sleeve (16) is distributed at equal angles on the outer wall of the rotating shaft (14), and the length of the piston sleeve (16) is less than the radius of the packing layer (7). The outer wall of the slide rod (17) is fitted with a compression spring (20), and one end of the compression spring (20) abuts against the outer wall of the striking block (19), and the other end of the compression spring (20) abuts against the end of the piston sleeve (16).

4. A recovery mechanism for N-methylpyrrolidone according to claim 1, characterized in that: The flange (15) is designed as an annular plate, and the length of the flange (15) is less than the distance between the bottom of the filler layer (7) and the slide rod (17). When the striking block (19) is in striking state, the outer wall of the striking block (19) is in contact with the inner wall of the flange (15). The cross section of the extrusion block (23) is designed as a trapezoid, and the extrusion block (23) and the slide rod (17) are arranged in a one-to-one correspondence. When not in striking state, the outer wall of the extrusion block (23) abuts against the end of the slide rod (17).

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