Intelligent wastewater treatment equipment for extracting N-methyl pyrrolidone and treatment method thereof

Abstract

The invention provides intelligent wastewater treatment equipment for extracting N-methyl pyrrolidone, which comprises a crystallizer box body, a crystallization plate assembly is arranged in the crystallizer box body, the crystallization plate assembly comprises a plurality of crystallization plates arranged in sequence and baffle plates arranged between two adjacent crystallization plates, and a medium channel is arranged in each crystallization plate; a plurality of groups of circulation openings for circulation of waste water extract are transversely formed in the crystallization plate; the baffle plate is continuously bent in an S shape, a plurality of protruding parts are transversely arranged on the two sides of the baffle plate, the protruding parts are longitudinally arranged, the protruding parts are attached to the surfaces of the crystallization plates on the two sides respectively and block and seal gaps between the crystallization plates, and the protruding parts are located on the two sides of every two adjacent circulation openings in the crystallization plates respectively. According to the cooling crystallization device, waste water extraction liquid sequentially penetrates through each group of circulation openings under the guiding action of the baffle plates on the two sides of the crystallization plate and flows back and forth on the two sides of the crystallization plate, so that a solution can be in full contact with the crystallization plate, the circulating flow guide device drives the solution to flow to realize circulation, and the cooling crystallization efficiency is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and specifically relates to intelligent wastewater treatment equipment for extracting N-methylpyrrolidone and a treatment method thereof. Background Art

[0002] N-methylpyrrolidone (NMP) is a polar solvent with strong selectivity and good stability and an important chemical raw material. It is also a polar non-proton transfer solvent with the advantages of low viscosity, good stability, high boiling point, strong solubility, recyclability, safe use and suitability for a variety of formulations. It is widely used in lithium-ion battery production and used as a solvent for binder PVDF. At present, separating NMP from wastewater and purifying it for recycling is a problem often encountered in the use and refining of NMP. In the prior art, the NMP wastewater recovery process first separates impurities from NMP wastewater through a pretreatment process, performs sand filtration, carbon filtration, reverse osmosis treatment and other processes, and then uses a solvent to extract the waste liquid to obtain an extract. Finally, the extract is sequentially frozen and crystallized by a primary and secondary step crystallizer, so that the NMP solvent is condensed and separated in the crystallizer to achieve NMP recovery and extraction.

[0003] Chinese patent document: CN202410261288.1, discloses a solvent recovery system and recovery method for para-aramid production. The application records the use of an extraction tower in conjunction with a primary step crystallizer and a secondary step crystallizer to achieve the recovery process of NMP. The crystallizer in the application adopts a shell-and-tube structure. Due to the limited space for crystal growth in the shell-and-tube crystallizer, small crystals are easily produced, which affects the overall crystallization efficiency, resulting in low NMP recovery efficiency. At the same time, more energy consumption is required during the crystal growth process in the shell-and-tube crystallizer, thereby increasing the cost of wastewater treatment. Summary of the invention

[0004] In view of the above problems, the present invention discloses an intelligent wastewater treatment device for extracting N-methylpyrrolidone and a treatment method thereof, which solves the problems of low recovery efficiency and high recovery cost of NMP wastewater treatment equipment in the prior art.

[0005] The specific technical solutions are as follows:

[0006] An intelligent wastewater treatment equipment for extracting N-methylpyrrolidone, comprising a crystallizer box, wherein the front end of the crystallizer box is contracted, and the rear end thereof is narrowed on both sides, and a liquid inlet pipe and a liquid outlet pipe are respectively arranged at the front and rear ends of the crystallizer box, and three-way valves are respectively arranged on the liquid inlet pipe and the liquid outlet pipe, and the two three-way solenoid valves are connected by a circulation pipeline, and a circulation pump for driving the wastewater extract to form a circulation flow in the crystallizer box is arranged on the circulation pipeline; a crystallization plate assembly is arranged in the crystallizer box, and the crystallization plate assembly includes a plurality of crystallization plates arranged in sequence and a baffle plate arranged between two adjacent crystallization plates, and each crystallization plate is provided with a medium channel distributed in an S shape inside, and the tops of the two ends of the medium channel are respectively connected to a collection arranged on the outside of the crystallizer box through connecting pipes. The pipes are connected, and the collecting pipes are respectively provided with a medium inlet pipe and a medium outlet pipe for connecting to an external heat exchange system; each of the crystallization plates is laterally arranged with a plurality of flow openings for the circulation of the wastewater extract, and the number of the flow openings in each group is a plurality and they are arranged longitudinally; the baffle is arranged in an S-shaped continuous bending, and both sides of the baffle are laterally arranged with a plurality of protrusions, and the protrusions are all arranged longitudinally, so that the protrusions on both sides of the baffle are respectively fitted with the surfaces of the crystallization plates on both sides and the gaps between the crystallization plates are blocked and sealed, and the position of each protrusion is respectively located on both sides of two adjacent groups of flow openings on the crystallization plates, so that the wastewater extract passes through each group of flow openings in turn under the guidance of the baffles on both sides of the crystallization plates and flows back and forth on both sides of the crystallization plates.

[0007] Furthermore, a steam exhaust pipe is provided on the top of the crystallizer box, a liquid discharge pipe is provided on the bottom of the crystallizer box, and a guide plate is obliquely provided in the middle of the lower end of the crystallizer box. The guide plate is used to guide the crystallization molten liquid flowing down the crystallization plate to the liquid discharge pipe, and the guide plate supports the bottom of the crystallization plate through a support.

[0008] Furthermore, the raised portions on both sides of the baffle are planar structures, and the raised portions are in contact with the positions of the medium channels on the crystallization plate; both sides of the raised portions are arranged with inclined surfaces, and the maximum spacing between the two inclined surfaces is greater than the spacing between two adjacent groups of flow ports, so that the wastewater extract can flow back and forth on both sides of the crystallization plate under the guidance of the baffle.

[0009] Furthermore, the surface of the crystallization plate is also provided with a cleaning assembly for cleaning the flow opening, the cleaning assembly includes a plurality of grooves arranged on the outside of each group of openings and a movable plate hingedly arranged on one side of each groove, the grooves are in the form of a longitudinally arranged long strip structure, and a movable plate is hingedly arranged on one side of each groove close to the protruding portion of the baffle plate, the movable plate moves outward under the support of the elastic member and presses against one side of the protruding portion of the baffle plate, a plurality of protrusions are longitudinally arranged on the inner surface of the movable plate, and the position of each protrusion corresponds to the position of a flow opening, the baffles are driven to move horizontally by a displacement driving device arranged in the crystallizer box, so that when the baffle moves horizontally, the movable plate is pushed to flip into the groove and the protrusion is embedded in the flow opening, so that the crystal blocks blocked in the flow opening are cleaned by the protrusions.

[0010] Furthermore, the displacement drive device includes a positioning frame, a screw rod, a driving motor, and a guide rail. There are two positioning frames and they are longitudinally arranged at the front and rear ends of the crystallization plate assembly, and each baffle is provided with a flat plate at the front and rear ends, respectively. The two flat plate portions extend in the directions of the two positioning frames and are connected and fixed to the surface of the positioning frames, and both sides of the positioning frame are horizontally slidably connected to the inner wall of the crystallizer box on both sides through the guide rails, and the left and right sides of the crystallizer box are protruding outward with accommodating cavities, and the accommodating cavities are in an "I"-shaped structure. Fixed plates are provided on both sides of each positioning frame and extend into the accommodating cavities on both sides, respectively, and the fixed plates are respectively threadedly connected to the screw rod horizontally rotatably arranged in the accommodating cavity, one end of the screw rod passes through one end of the accommodating cavity and is driven to rotate by a driving motor arranged on the outer wall of the crystallizer box, so that the two positioning frames drive a number of baffles to move forward and backward synchronously under the action of the screw rod thread, so that the baffle and the movable plate are pressed together to drive the movable plate to flip and realize the dredging and cleaning of the convection port through the protrusion.

[0011] Furthermore, the positioning frame is in a square frame structure, and a plurality of sockets are arranged horizontally at the upper and lower ends of the positioning frame for plugging and fixing with one end of the baffle. The sockets are fixed by fasteners that horizontally penetrate one end of the baffle.

[0012] Furthermore, a control system is included, which includes a PLC controller and a flow meter arranged on the circulation pipeline, and the PLC controller is respectively connected to the flow meter, the drive motor, the circulation pump and two three-way solenoid valves.

[0013] A treatment method of an intelligent wastewater treatment device for extracting N-methylpyrrolidone, specifically comprising the following steps:

[0014] Step 1: inject the wastewater extract into the crystallizer box, and circulate it in the crystallizer box driven by a circulation pump;

[0015] Step 2: Control the heating temperature of the circulating medium flowing through the crystallization plate to be maintained at 100° C. to 120° C. through a heat exchange system to evaporate the water contained in the wastewater extract;

[0016] Step 3: The cooling temperature of the circulating medium in the crystallization plate is controlled by the heat exchange system to be maintained at -10°C to -5°C, so that the NMP solvent contained in the wastewater extract is crystallized and precipitated, and the remaining uncrystallized wastewater extract is discharged from the liquid outlet pipe;

[0017] Step 4: Finally, the heat exchange system is used to control the heating temperature of the circulating medium flowing through the crystallization plate to be maintained at 5°C to 15°C, so that the NMP solvent crystallized on the crystallization plate is melted and discharged through the NMP solvent drain pipe.

[0018] The beneficial effects of the present invention are embodied in:

[0019] (1) In the present invention, the crystallization plate assembly in the crystallizer is provided with a plurality of groups of flow openings on the crystallization plate and is blocked and guided by baffles, so that the solution passes through each group of flow openings in turn under the guidance of the baffles and flows back and forth on both sides of the crystallization plate, so that the solution can fully contact the crystallization plate, and the circulation guide device drives the solution flow to realize circulation, thereby greatly improving the cooling crystallization efficiency.

[0020] (2) In the present invention, a cleaning assembly is provided at each group of flow openings on the crystallization plate, which drives the baffle plate to move synchronously, so that the baffle plate presses against the movable plate and clears the crystal blocks in the flow openings through the protrusions, thereby avoiding blockage of the flow openings and allowing the solution to flow smoothly in the flow openings, thereby ensuring the stable operation of the crystallizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 Schematic diagram of the internal structure of the crystallizer in Example 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the working principle of the crystallization plate assembly of Example 1 of the present invention.

[0024] Figure 4 It is a transverse cross-sectional view of the crystallizer in Example 2 of the present invention.

[0025] Figure 5 A side cross-sectional view of a crystal plate in Example 2 of the present invention

[0026] Figure 6 Schematic diagram of the structure between the cleaning component and the crystallization plate and the baffle plate in Example 2 of the present invention

[0027] Explanation of the accompanying drawings: crystallizer box 1, liquid inlet pipe 101, liquid outlet pipe 102, three-way solenoid valve 103, collecting pipe 11, medium inlet pipe 11-1, medium outlet pipe 11-2, exhaust pipe 12, liquid discharge pipe 13, accommodating chamber 14, crystallization plate 2, medium channel 2-1, flow port 2-2, groove 2-3, movable plate 2-4, protrusion 2-4-1, elastic member 2-5, baffle 3, raised portion 3-1, flat plate portion 3-2, guide plate 4, displacement drive device 5, positioning frame 51, socket 51-1, fixing plate 51-2, screw 52, ​​drive motor 53, guide rail 54, circulation pipe 6, flow meter 61, circulation pump 7. DETAILED DESCRIPTION

[0028] In order to make the technical solution of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. Any equivalent replacement of the technical features of the technical solution of the present invention and any solution derived from conventional reasoning shall fall within the protection scope of the present invention. The fixed connection and fixed setting mentioned in the present invention are all common connection methods in the mechanical field, including welding, bolt and nut connection, and screw connection.

[0029] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0030] Example 1

[0031] like Figure 1-3As shown, the present embodiment provides an intelligent wastewater treatment device for extracting N-methylpyrrolidone, including a crystallizer housing 1, the crystallizer housing is in a rectangular structure, the front end of the crystallizer housing 1 is contracted, and the rear end is narrowed on both sides, and the front and rear ends of the crystallizer housing 1 are respectively provided with a liquid inlet pipe 101 and a liquid outlet pipe 102, and the liquid inlet pipe 101 and the liquid outlet pipe 102 are respectively provided with a three-way valve, and the two three-way solenoid valves 103 are connected by a circulation pipe 6, and the circulation pipe 6 is provided with a valve for driving the wastewater extract in A circulating pump 7 is formed in the crystallizer housing 1 to form a circulating flow; a crystallizer plate assembly is arranged in the crystallizer housing 1, and the crystallizer plate assembly includes a plurality of crystallizer plates 2 arranged in sequence and a baffle 3 arranged between two adjacent crystallizer plates 2, each crystallizer plate 2 is provided with an S-shaped medium channel 2-1 inside, and the tops of both ends of the medium channel 2-1 are connected to a manifold 11 arranged outside the crystallizer housing 1 through connecting pipes, and the manifold 11 is provided with a medium inlet pipe 11-11 for connecting to an external heat exchange system. 1 and a medium outlet pipe 11-2, so that the circulating medium forms a cycle in the crystallizer box 1 and realizes the heating and cooling of the crystallization plate 2. In this embodiment, the circulating medium is heat transfer oil; each crystallization plate 2 is horizontally arranged with a plurality of flow openings 2-2 for the flow of wastewater extract, and the number of the flow openings 2-2 in each group is a plurality and they are arranged vertically; the baffle 3 is arranged in an S-shaped continuous bending, and a plurality of protrusions 3-1 are horizontally arranged on both sides of the baffle 3, and the protrusions 3-1 are all plane structures The structure is arranged longitudinally, so that the raised portions 3-1 on both sides of the baffle plate 3 are respectively arranged in contact with the surfaces of the crystallization plates 2 on both sides and block and seal the gap between the crystallization plates 2, and the position of each raised portion 3-1 is respectively located on both sides of two adjacent groups of flow ports 2-2 on the crystallization plate 2, so that the wastewater extract passes through each group of flow ports 2-2 in turn under the guidance of the baffle plates 3 on both sides of the crystallization plate 2 and flows back and forth on both sides of the crystallization plate 2, so that the solution can fully contact the crystallization plate 2 to improve the evaporation and crystallization efficiency.

[0032] In this embodiment, a steam exhaust pipe 12 is provided on the top of the crystallizer box 1, a liquid discharge pipe 13 for discharging the NMP crystallization melt is provided at the bottom of the crystallizer box 1, and a guide plate 4 is obliquely provided at the middle of the lower end of the crystallizer box 1. The guide plate 4 is used to guide the crystallization melt flowing down from the crystallization plate 2 to the liquid discharge pipe 13. A plurality of supports are arranged horizontally on the guide plate 4, and each support supports the bottom of each crystallization plate 2 respectively.

[0033] In this embodiment, the protrusions 3-1 on both sides of the baffle 3 are both planar structures, and the protrusions 3-1 are in contact with the positions of the medium channels 2-1 on the crystallization plate 2, so as to improve the heat conduction efficiency, so that the baffle 3 can play a certain heat exchange role, thereby increasing the heat exchange area. Both sides of the protrusion 3-1 are arranged with inclined surfaces, and the maximum spacing between the two inclined surfaces is greater than the spacing between two adjacent groups of flow ports 2-2, so that the solution can flow back and forth on both sides of the crystallization plate 2 under the guidance of the baffle 3.

[0034] This embodiment also provides a treatment method of an intelligent wastewater treatment device for extracting N-methylpyrrolidone, which includes the following steps.

[0035] Step 1: inject the wastewater extract into the crystallizer housing 1, and circulate it in the crystallizer housing 1 driven by the circulation pump 7;

[0036] Step 2: The heating temperature of the circulating medium flowing through the crystallization plate 2 is controlled by the heat exchange system to be maintained at 100° C. to 120° C., so as to evaporate the water contained in the wastewater extract;

[0037] Step 3: The cooling temperature of the circulating medium in the crystallization plate 2 is controlled by the heat exchange system to be maintained at -10°C to -5°C, so that the NMP solvent contained in the wastewater extract is crystallized and precipitated, and the remaining uncrystallized wastewater extract is discharged from the liquid outlet pipe 102;

[0038] Step 4: Finally, the heat exchange system is used to control the heating temperature of the circulating medium flowing through the crystallization plate 2 to be maintained at 5°C to 15°C, so that the NMP solvent crystallized on the crystallization plate 2 is melted and discharged through the NMP solvent drain pipe 13, thereby finally completing the extraction of NMP solvent from NMP wastewater.

[0039] Embodiment 2

[0040] like Figure 4-6As shown, in order to prevent the solution from forming crystal blocks at the flow port 2-2 during the cooling crystallization process of the crystallizer, and the crystal blocks from adhering in the flow port 2-2, thereby causing blockage of the flow port 2-2, the difference between this embodiment and embodiment 1 is that a cleaning component for cleaning the flow port 2-2 is further provided on the surface of the crystallization plate 2, and the cleaning component includes a plurality of grooves 2-3 arranged on the outside of each group of through ports and a movable plate 2-4 hingedly arranged on one side of each groove 2-3, the grooves 2-3 are longitudinally arranged long strip structures, and a movable plate 2-4 is hingedly arranged on one side of each groove 2-3 close to the raised portion 3-1 of the baffle plate 3, and an elastic member 2-5 is arranged on the inner side of the movable plate 2-4, and the elastic member 2-5 is V-shaped The movable plate 2-4 is supported by the elastic member 2-5 and moves outward and presses against one side of the raised portion 3-1 of the baffle plate 3. A plurality of protrusions 2-4-1 are arranged longitudinally on the inner surface of the movable plate 2-4. The position of each protrusion 2-4-1 corresponds to the position of a flow port 2-2. The baffle plates 3 are driven to move laterally by the displacement drive device 5 arranged in the crystallizer box 1, so that when the baffle plate 3 moves laterally, it pushes the movable plate 2-4 to flip into the groove 2-3 and embeds the protrusion 2-4-1 into the flow port 2-2. The protrusion 2-4-1 is embedded in the flow port 2-2, so that the crystal block is separated from the inner wall of the flow port 2-2 to clean the blocked crystal block.

[0041] In this embodiment, the displacement drive device 5 includes a positioning frame 51, a screw rod 52, a drive motor 53, and a guide rail 54. The number of the positioning frames 51 is two and they are longitudinally arranged at the front and rear ends of the crystallization plate assembly, and the front and rear ends of each baffle 3 are respectively provided with a flat plate portion 3-2, and the two flat plate portions 3-2 extend toward the two positioning frames 51 and are connected and fixed to the surface of the positioning frames 51. Both sides of the positioning frame 51 are horizontally slidably connected to the inner walls of the crystallizer box 1 through the guide rails 54, and the left and right sides of the crystallizer box 1 are protruded outwardly with a accommodating cavity 14, and the accommodating cavity 14 is in a "one"-shaped structure. Fixed plates 51-2 are provided on both sides of each positioning frame 51 and extend into the accommodating chambers 14 on both sides respectively, and the fixed plates 51-2 are respectively threadedly connected with the screw rods 52 horizontally rotatably arranged in the accommodating chamber 14, one end of the screw rod 52 passes through one end of the accommodating chamber 14 and is driven to rotate by a driving motor 53 arranged on the outer wall of the crystallizer box 1, so that the two positioning frames 51 drive a number of baffles 3 to move forward and backward synchronously under the action of the screw rod 52 threads, so that the baffles 3 and the movable plates 2-4 are pressed and matched to drive the movable plates 2-4 to flip and realize the dredging and cleaning of the convection port 2-2 through the protrusion 2-4-1.

[0042] In this embodiment, the positioning frame 51 is in a square frame structure and the interior of the positioning frame 51 is used for the circulation of wastewater extract. A plurality of sockets 51-1 for plugging and fixing with the upper and lower ends of one end of the baffle 3 are arranged horizontally at the upper and lower ends of the positioning frame 51. The sockets 51-1 are fixed by fasteners that horizontally penetrate one end of the baffle 3.

[0043] In this embodiment, a control system is also included. The control system includes a PLC controller and a flow meter 61 arranged on the circulation pipe 6. The PLC controller is respectively connected to the flow meter 61, the drive motor 53, the circulation pump 7 and the two three-way solenoid valves 103. The flow meter 61 is used to monitor the flow rate of the flowing solution in the circulation pipe 6. When the flow rate decreases, it means that the flow port 2-2 of the crystallization plate 2 is blocked. Then the PLC controller controls the drive motor 53 to start, and drives the baffle 3 to move forward and backward in sequence through the displacement drive device 5, so that the movable plate 2-4 is flipped and the flow port 2-2 is cleaned by the protrusion 2-4-1.

[0044] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An intelligent wastewater treatment equipment for extracting N-methylpyrrolidone, characterized in that: The invention comprises a crystallizer housing (1), wherein the front end of the crystallizer housing (1) is contracted and the rear end is narrowed on both sides, and the front and rear ends of the crystallizer housing (1) are respectively provided with a liquid inlet pipe (101) and a liquid outlet pipe (102), and the liquid inlet pipe (101) and the liquid outlet pipe (102) are respectively provided with a three-way valve, and the two three-way solenoid valves (103) are connected by a circulation pipe (6), and the circulation pipe (6) is provided with a valve for driving the wastewater extract to form a liquid in the crystallizer housing (1). A circulating pump (7) for circulating flow; a crystallization plate assembly is arranged in the crystallizer housing (1), the crystallization plate assembly includes a plurality of crystallization plates (2) arranged in sequence and a baffle (3) arranged between two adjacent crystallization plates (2); each crystallization plate (2) is provided with a medium channel (2-1) distributed in an S shape inside, and the tops of both ends of the medium channel (2-1) are connected to a collection pipe (11) arranged outside the crystallizer housing (1) through connecting pipes, and the collection pipe (11) is respectively provided with There are a medium inlet pipe (11-1) and a medium outlet pipe (11-2) for connecting to an external heat exchange system; each of the crystallization plates (2) is provided with a plurality of groups of flow openings (2-2) for the flow of wastewater extract, and the number of the flow openings (2-2) in each group is a plurality and they are arranged in a longitudinal direction; the baffle plate (3) is arranged in an S-shaped continuous bending, and a plurality of protrusions (3-1) are arranged in a transverse direction on both sides of the baffle plate (3), and the protrusions (3-1) are The baffles (3-1) are arranged longitudinally so that the raised portions (3-1) on both sides of the baffles (3) are respectively arranged in contact with the surfaces of the crystallization plates (2) on both sides and block and seal the gap between the crystallization plates (2), and each raised portion (3-1) is respectively located on both sides of two adjacent groups of flow openings (2-2) on the crystallization plates (2), so that the wastewater extract passes through each group of flow openings (2-2) in sequence under the guidance of the baffles (3) on both sides of the crystallization plates (2) and flows back and forth on both sides of the crystallization plates (2).

2. The intelligent wastewater treatment equipment for extracting N-methylpyrrolidone according to claim 1, characterized in that: The top of the crystallizer box (1) is provided with an exhaust pipe (12), the bottom of the crystallizer box (1) is provided with a liquid discharge pipe (13), and a guide plate (4) is obliquely provided at the middle of the lower end of the crystallizer box (1), the guide plate (4) is used to guide the crystallization melt flowing down from the crystallization plate (2) to the liquid discharge pipe (13), and the guide plate (4) supports the bottom of the crystallization plate (2) through a support.

3. The intelligent wastewater treatment equipment for extracting N-methylpyrrolidone according to claim 1, characterized in that: The raised portions (3-1) on both sides of the baffle (3) are both planar structures, and the raised portions (3-1) are in contact with the positions of the medium channels (2-1) on the crystallization plate (2); both sides of the raised portions (3-1) are arranged as inclined surfaces, and the maximum distance between the two inclined surfaces is greater than the distance between two adjacent groups of flow openings (2-2), so that the wastewater extract can flow back and forth on both sides of the crystallization plate (2) under the guidance of the baffle (3).

4. The intelligent wastewater treatment equipment for extracting N-methylpyrrolidone according to claim 3, characterized in that: The surface of the crystallization plate (2) is also provided with a cleaning assembly for cleaning the flow opening (2-2), the cleaning assembly comprising a plurality of grooves (2-3) arranged on the outside of each group of openings and a movable plate (2-4) hingedly arranged on one side of each groove (2-3), the grooves (2-3) being in a longitudinally arranged long strip structure, a movable plate (2-4) being hingedly arranged on one side of each groove (2-3) close to the raised portion (3-1) of the baffle plate (3), the movable plate (2-4) being supported by the elastic member (2-5) and moving outward and pressing against one side of the raised portion (3-1) of the baffle plate (3). On the side, a plurality of protrusions (2-4-1) are arranged longitudinally on the inner surface of the movable plate (2-4), and the position of each protrusion (2-4-1) corresponds to the position of a flow port (2-2). The baffle plates (3) are driven to move laterally by a displacement drive device (5) arranged in the crystallizer box (1), so that when the baffle plates (3) move laterally, they push the movable plate (2-4) to flip into the groove (2-3) and make the protrusions (2-4-1) embedded in the flow port (2-2), so that the crystal blocks blocked in the flow port (2-2) are cleaned by the protrusions (2-4-1).

5. The intelligent wastewater treatment equipment for extracting N-methylpyrrolidone according to claim 4, characterized in that: The displacement drive device (5) comprises a positioning frame (51), a screw rod (52), a drive motor (53), and a guide rail (54). The positioning frames (51) are two in number and are respectively longitudinally arranged at the front and rear ends of the crystallization plate assembly, and each baffle plate (3) is respectively provided with a flat plate portion (3-2) at the front and rear ends, and the two flat plate portions (3-2) extend in the direction of the two positioning frames (51) and are connected and fixed to the surface of the positioning frames (51). Both sides of the positioning frame (51) are horizontally slidably connected to both sides of the inner wall of the crystallizer box (1) through the guide rail (54), and the left and right sides of the crystallizer box (1) are protruding outwardly and are provided with a receiving cavity (14), and the receiving cavity (14) is in an "I"-shaped structure. Each positioning frame (51) is provided with a plurality of movable members (14) and a plurality of movable members (14) are provided with ... Fixed plates (51-2) are provided on both sides of the frame (51) and extend into the accommodating chambers (14) on both sides respectively, and the fixed plates (51-2) are respectively threadedly connected with screw rods (52) horizontally rotatably arranged in the accommodating chamber (14), one end of the screw rod (52) passes through one end of the accommodating chamber (14) and is respectively driven to rotate by a driving motor (53) arranged on the outer wall of the crystallizer box (1), so that the two positioning frames (51) drive a plurality of baffle plates (3) to move forward and backward synchronously under the action of the screw rod (52) threads, so that the baffle plates (3) and the movable plates (2-4) are pressed and matched to drive the movable plates (2-4) to flip and realize the dredging and cleaning of the convection port (2-2) through the protrusions (2-4-1).

6. The intelligent wastewater treatment equipment for extracting N-methylpyrrolidone according to claim 5, characterized in that: The positioning frame (51) is in a square frame structure, and a plurality of plug sockets (51-1) for plugging and fixing with one end of the baffle (3) are arranged transversely at the upper and lower ends of the positioning frame (51), and the plug sockets (51-1) are fixed by fasteners that horizontally penetrate one end of the baffle (3).

7. The intelligent wastewater treatment equipment for extracting N-methylpyrrolidone according to claim 1, characterized in that: The system also includes a control system, which includes a PLC controller and a flow meter (61) arranged on the circulation pipe (6), wherein the PLC controller is respectively connected to the flow meter (61), the drive motor (53), the circulation pump (7) and the two three-way solenoid valves (103).

8. A method for treating N-methylpyrrolidone by an intelligent wastewater treatment device according to any one of claims 1 to 7, comprising the following steps: Step 1: injecting the wastewater extract into the crystallizer housing (1), and circulating the extract in the crystallizer housing (1) driven by a circulation pump (7); Step 2: controlling the heating temperature of the circulating medium flowing through the crystallization plate (2) to be maintained at 100° C. to 120° C. by a heat exchange system to evaporate the water contained in the wastewater extract; Step 3: The circulating medium in the crystallization plate (2) is controlled by a heat exchange system to maintain a cooling temperature of -10°C to -5°C, so that the NMP solvent contained in the wastewater extract is crystallized and precipitated, and the remaining uncrystallized wastewater extract is discharged from the liquid outlet pipe (102); Step 4: Finally, the heat exchange system is used to control the heating temperature of the circulating medium flowing through the crystallization plate (2) to be maintained at 5°C to 15°C, so that the NMP solvent crystallized on the crystallization plate (2) is melted and discharged through the NMP solvent drain pipe (13).

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