NMP multi-stage rectification purification equipment and process

Abstract

The invention relates to the technical field of NMP (N-Methyl Pyrrolidone) purification, in particular to NMP multi-stage rectification purification equipment and process. A first cavity is formed in a shell at the top of the third-stage reaction kettle, a steam inlet hole communicated with the first cavity is formed in the inner wall of the top of the third-stage reaction kettle, refrigeration equipment is arranged in the first cavity, and a discharging pipe communicated with the first cavity is mounted on the third-stage reaction kettle; the distillation device is used for purifying and distilling an NMP solution into the first cavity and flowing out of the discharging pipe to obtain purified NMP; a heating mechanism is arranged in the third-stage reaction kettle; the third-stage reaction kettle is communicated with a feeding pipe, and a waste material outlet is formed in the third-stage reaction kettle. According to the device, after NMP is obtained through third-stage distillation and purification, the internal structure can be controlled through an external motor to efficiently clean internal residual waste materials, and the residual waste materials are conveyed to the outside, so that the use efficiency of the device is improved.

Description

Technical Field

[0001] The present invention relates to the field of NMP purification devices, in particular to NMP multi-stage distillation purification equipment and technology. Background Art

[0002] N-Methylpyrrolidone (NMP), abbreviated as NMP, is an important chemical raw material and a highly selective and stable polar solvent. It is also a commonly used solvent in lithium battery production. During the production of positive and negative electrode materials and separators for lithium batteries, NMP solvent evaporates and is recovered in a high-tower recovery unit to produce an 80% NMP recovery liquid. After further purification in our company's three-stage distillation unit, the NMP solvent reaches electronic grade and can be reused.

[0003] The first stage is to remove most of the water in the solution by low-temperature evaporation using a heat pump. The second stage is to remove trace water in the NMP solution by vacuum flash evaporation. The third stage is to purify the NMP by distillation.

[0004] However, after the third stage of distillation, residual waste remains, which needs to be removed before the next round of reaction operations can proceed. If personnel disassemble the reactor to clean the residual waste, it will be time-consuming and will also lead to poor sealing. Therefore, a device is needed to automatically clean the residual waste. However, this device is a distillation device, and the reactor is not suitable for direct electrical control to perform cleaning operations.

[0005] In view of the above difficulties, we have designed a multi-stage distillation purification equipment and process for NMP. After the third stage of distillation purification to NMP, the internal structure can be controlled by an external motor to efficiently clean the residual waste inside and transmit it to the outside world, thereby improving the utilization efficiency of the device. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the existing technology. The present invention proposes a multi-stage distillation purification device and process for NMP. After the third-stage distillation purification to NMP, the internal structure can be controlled by an external motor to efficiently clean the residual waste inside and transmit it to the outside world, thereby improving the utilization efficiency of the device.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: NMP multi-stage distillation purification equipment, comprising:

[0008] The third stage reactor;

[0009] A first cavity is defined within the top shell of the third-stage reactor, a steam inlet hole is defined on the top inner wall of the third-stage reactor and is communicated with the first cavity, a refrigeration device is provided within the first cavity, and a discharge pipe connected to the first cavity is installed on the third-stage reactor for purifying and distilling the NMP solution into the first cavity and discharging the purified NMP from the discharge pipe;

[0010] The third-stage reactor is provided with a heating mechanism for heating NMP;

[0011] The third-stage reactor is connected to a feed pipe, a waste outlet is provided on the third-stage reactor, and a sealing door for sealing the waste outlet is installed on the third-stage reactor;

[0012] A collecting shovel frame is provided in the third-stage reactor, and a driving mechanism is provided in the third-stage reactor, so that the collecting shovel frame can move up and down, left and right, and rotate, so that the collecting shovel frame can shovel the residual waste at the bottom of the third-stage reactor into the collecting shovel frame, and transfer the residual waste in the collecting shovel frame from the waste outlet to the outside of the third-stage reactor for dumping, thereby realizing the waste removal operation, and the collecting shovel frame is stirred when NMP is distilled or when preparing to remove the residual waste, thereby better distillation operation and facilitating better removal of residual waste.

[0013] Furthermore, it also includes a first-stage low-temperature evaporation and concentration device and a raw liquid storage tank. The first-stage low-temperature evaporation and concentration device is connected to the raw liquid storage tank through a liquid transmission mechanism, and the first-stage low-temperature evaporation and concentration device is connected to the feed pipe through the liquid transmission mechanism.

[0014] Furthermore, it also includes a second-stage heat pump low-temperature flash evaporation equipment. The first-stage low-temperature evaporation and concentration equipment is also connected to the second-stage heat pump low-temperature flash evaporation equipment through a liquid transmission mechanism. The second-stage heat pump low-temperature flash evaporation equipment is connected to the feed pipe through the liquid transmission mechanism.

[0015] Furthermore, the liquid conveying mechanism includes a conveying pipe, and a pump body is installed in the middle of the conveying pipe, which is used to allow one end of the conveying pipe to absorb liquid and the other end to discharge liquid. One end of the conveying pipe is connected to the liquid outlet of the raw liquid storage tank or the liquid outlet of the first-stage low-temperature evaporation and concentration equipment or the liquid outlet of the second-stage heat pump low-temperature flash evaporation equipment, and the other end of the conveying pipe is connected to the liquid inlet of the first-stage low-temperature evaporation and concentration equipment or the liquid inlet of the second-stage heat pump low-temperature flash evaporation equipment or the conveying pipe.

[0016] Furthermore, the heating mechanism includes an explosion-proof heating rod, a second cavity is opened in the inner cavity of the bottom shell of the third-stage reactor, the second cavity is filled with hot kerosene medium, and the explosion-proof heating rod is installed in the second cavity.

[0017] Furthermore, the driving mechanism includes a spline shaft, the spline shaft is limitedly connected to the top of the third-stage reactor for rotation, the outer wall of the spline shaft is limitedly connected to a spline sleeve for sliding movement, a first motor is fixedly installed on the top of the third-stage reactor, the power output end of the first motor is connected to the spline shaft, the bottom of the spline sleeve is fixedly connected to a first fixing plate, and a lifting mechanism is provided on the spline sleeve;

[0018] The first fixed plate is connected to the slide plate through an auxiliary elastic telescopic mechanism, and the slide plate is slidably connected to the limit slide plate in a left and right limited manner through a first limit slide groove provided on the slide plate, and a hinge rod is hinged between the first fixed plate and the limit slide plate, and the limit slide plate is rotatably connected to the first rotating column on the outer wall near the bottom, and the outer wall of the first rotating column is fixedly connected to the second mounting plate, and the bottom of one side of the second mounting plate is fixedly connected to the collecting shovel frame;

[0019] The outer wall of the limiting slide is fixedly connected to a first mounting plate, and the first mounting plate is pressed on the top of the other side of the second mounting plate through an elastic telescopic rod, so as to keep the collecting shovel frame in a preset state to shovel residual waste at the bottom of the third-stage reactor;

[0020] The outer wall of the third-stage reactor is detachably mounted with a waste collection frame for collecting residual waste shoveled out by the collection shovel frame;

[0021] The third-stage reactor is provided with a dumping mechanism which enables the collecting shovel frame to be in an inclined state after being moved out of the waste outlet to the outside of the third-stage reactor.

[0022] Furthermore, the lifting mechanism includes a threaded rod, the inner top of the third-stage reactor is limited and rotatably connected to the threaded rod, the inner wall of the third-stage reactor is fixedly installed with a second fixed plate, the threaded rod is limited and rotatably connected to the second fixed plate, the top of the third-stage reactor is fixedly installed with a second motor, the power output end of the second motor is connected to the threaded rod, the outer wall of the threaded rod is threadedly connected to a limiting slide, the limiting slide is slidably connected up and down in the second limiting groove on the inner wall of the third-stage reactor, a connecting plate is fixedly connected to the limiting slide, a bearing seat is fixedly installed on the connecting plate, and the spline sleeve is limited and rotatably connected in the bearing seat.

[0023] Furthermore, the auxiliary elastic telescopic mechanism includes a first telescopic rod and a first sliding sleeve, the bottom of the first fixed plate is fixedly connected to the first telescopic rod, the outer wall of the first telescopic rod is slidingly connected to the first sliding sleeve, the bottom of the first sliding sleeve is fixedly connected to the top of the slide rail plate, the inner bottom of the first sliding sleeve is fixedly connected to the second elastic member, and the end of the second elastic member away from the inner bottom of the first sliding sleeve is fixedly connected to the first telescopic rod; the elastic telescopic rod includes a second sliding sleeve and a second telescopic rod, the second sliding sleeve is fixedly connected to the bottom of the first mounting plate, the second telescopic rod is slidingly connected in the second sliding sleeve, the inner top of the second sliding sleeve is fixedly connected to the third elastic member, the bottom of the third elastic member is fixedly connected to the top of the second telescopic rod, the bottom of the second telescopic rod is fixedly installed with an elastic ball, and the elastic ball is squeezed against the top of the second mounting plate.

[0024] Furthermore, the dumping mechanism includes a triangular plate, the limiting slide is connected to the triangular plate in an upper and lower limiting sliding manner, the limiting slide is fixedly connected to a third fixed plate, the third fixed plate is provided with a third limiting sliding groove, the third limiting sliding groove is connected to a pressure column in an upper and lower limiting sliding manner, the top of the pressure column is fixedly connected to the bottom of the triangular plate, a first elastic member is fixedly connected between the triangular plate and the third fixed plate, and the bottom of the pressure column is pressed against the top of one side of the second mounting plate;

[0025] It also includes a wedge plate, which is fixedly installed on the inner wall of the third-stage reactor. The triangular plate cooperates with the wedge plate to enable the pressure column to move downward and tilt the collecting shovel frame downward.

[0026] The NMP multi-stage distillation purification process, using the above-mentioned NMP multi-stage distillation purification equipment, includes:

[0027] S1: Start the pump between the raw liquid storage tank and the first-stage low-temperature evaporation and concentration equipment to transfer the NMP recovery liquid in the raw liquid storage tank to the first-stage low-temperature evaporation and concentration equipment for the first distillation to remove moisture from the NMP recovery liquid;

[0028] S2: Start the pump between the first-stage low-temperature evaporation and concentration equipment and the second-stage heat pump low-temperature flash evaporation equipment to transfer the NMP recovery liquid after the first distillation in the first-stage low-temperature evaporation and concentration equipment to the second-stage heat pump low-temperature flash evaporation equipment to remove trace moisture again;

[0029] S3: Start the pump between the second-stage heat pump low-temperature flash evaporation device and the third-stage reactor to transfer the NMP recovery liquid distilled from the second-stage heat pump low-temperature flash evaporation device to the third-stage reactor. At this time, start the power supply of the explosion-proof heating rod to heat the hot kerosene medium in the second cavity, thereby heating and distilling the NMP recovery liquid in the third-stage reactor. At this time, start the refrigeration equipment to convert the NMP recovery liquid vapor into liquid and collect it in the first cavity and discharge it from the discharge pipe to obtain purified NMP;

[0030] S4: When distilling the NMP recovery liquid in the third-stage reactor, the second motor is started to move the bearing seat, the spline shaft sleeve, and the collecting shovel frame up and down so that the collecting shovel frame does not contact the bottom of the third-stage reactor. Then, the first motor is started to rotate the second mounting plate and the collecting shovel frame to stir the NMP recovery liquid, thereby allowing the NMP recovery liquid to be better heated and thus increasing the distillation speed;

[0031] S5: At the end of distillation, the feed pipe and the conveying pipe can be removed and the cleaning liquid can be injected through the feed pipe. At this time, the second motor is started to make the spline sleeve and the first fixed plate descend to the preset position. At this time, the collecting shovel frame is just placed on the inner bottom of the third-stage reactor. Then the second motor is started again to make the spline sleeve and the first fixed plate continue to move downward by a preset distance. At this time, the second elastic member in the first sliding sleeve contracts. The collecting shovel frame moves to one side at the bottom of the third-stage reactor and moves to the side wall of the third-stage reactor, shoveling the residual waste at the bottom of the third-stage reactor into the collecting shovel frame. Then the second motor is started again to make the collecting shovel frame return to the position just placed on the inner bottom of the third-stage reactor. At this time, the first motor is started to make the collecting shovel frame rotate by a preset angle. Then the second motor is started to make the spline sleeve and the first fixed plate continue to move downward by a preset distance. At this time, the collecting shovel frame shovels the residual waste at another angle of the bottom of the third-stage reactor into the collecting shovel frame. Repeat the above operation to shovel the residual waste at various positions on the bottom of the third-stage reactor into the collecting shovel frame.

[0032] S6: Open the sealing door, start the first motor to make the collecting shovel frame face the waste outlet, start the second motor to make the spline shaft sleeve and the first fixed plate drop a greater distance, and the collecting shovel frame moves from the waste outlet to the outside of the third-stage reactor. Then, the triangular plate and the wedge plate cooperate with each other, so that the pressure column squeezes the second mounting plate, making the collecting shovel frame tilted, and pouring the waste into the waste collecting frame, completing the waste shoveling at the bottom of the third-stage reactor;

[0033] S7: Close the sealing door, remove the feed pipe and the conveying pipe, and inject the cleaning liquid through the feed pipe. At this time, start the first motor to make the second mounting plate and the collecting shovel frame stir the liquid in the third-stage reactor to clean the inside of the third-stage reactor. Then open the sealing door to release the cleaning liquid, and then use the collecting shovel frame to shovel out the bottom waste at the bottom of the third-stage reactor and convey it to the outside, thereby completing the cleaning of the inside of the third-stage reactor.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The water in the NMP recovery liquid can be distilled and removed through the first-stage low-temperature evaporation and concentration equipment and the second-stage heat pump low-temperature flash evaporation equipment, and then the NMP is distilled and purified through the mechanism in the third-stage reactor to obtain purified NMP;

[0036] The direction of the collecting shovel frame can be adjusted so that the collecting shovel frame can shovel the residual waste from various positions of the third-stage reactor onto the collecting shovel frame, and the shoveled residual waste can be transferred to the waste collection frame;

[0037] The cleaning liquid can be injected into the third-stage reactor, and the interior of the third-stage reactor can be cleaned by rotating the second mounting plate and the collecting shovel frame. Then, the residual waste inside the third-stage reactor can be better removed by shoveling out the residual waste inside the third-stage reactor.

[0038] Moreover, when the second mounting plate and the collecting shovel frame are rotated, the distillation speed of the NMP recovery liquid in the third-stage reactor is accelerated, thereby improving the operating efficiency. The collecting shovel frame for automatically cleaning and removing the waste inside the third-stage reactor shortens the maintenance time of the device, thereby improving the operating efficiency. The interior of the third-stage reactor can be maintained frequently, making the device cleaner and relatively increasing the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The disclosure of the present invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them:

[0040] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0041] Figure 2 Schematic diagram of the cross-sectional structure of the third-stage reactor of the present invention;

[0042] Figure 3 For the present invention Figure 2 The enlarged structural diagram at the bottom;

[0043] Figure 4 For the present invention Figure 2Schematic diagram of the enlarged structure at A;

[0044] Figure 5 For the present invention Figure 3 Schematic diagram of the enlarged structure at B;

[0045] Figure 6 For the present invention Figure 5 Schematic diagram of the enlarged structure at C;

[0046] Figure 7 Schematic diagram of the cross-sectional structure of the first telescopic rod and the first sliding sleeve of the present invention;

[0047] Figure 8 It is a cross-sectional schematic diagram of the cooperation between the second sliding sleeve and the second telescopic rod of the present invention.

[0048] Numbers in the figure: 1. Frame; 2. Raw liquid storage tank; 3. First-stage low-temperature evaporation and concentration equipment; 4. Second-stage heat pump low-temperature flash equipment; 5. Third-stage reactor; 6. First cavity; 7. Pump body; 8. Conveying pipe; 9. Discharge pipe; 10. Waste collection frame; 11. Sealing door; 12. Spline bushing; 13. First fixed plate; 14. First telescopic rod; 15. Articulated rod; 16. Slide plate; 17. First limiting slide; 18. Feed pipe; 19. Second cavity; 20. Explosion-proof heating rod; 21. Waste outlet; 22. First sleeve; 23. Wedge plate; 24. Limiting slide plate; 25. First mounting plate ; 26. Elastic telescopic rod; 27. Second mounting plate; 28. First rotating column; 29. ​​Collecting shovel frame; 30. First motor; 31. Second motor; 32. Refrigeration equipment; 33. Second fixed plate; 34. Steam inlet hole; 35. Spline shaft; 36. Bearing seat; 37. Connecting plate; 38. Threaded rod; 39. Limiting slide; 40. Second limiting slide groove; 41. Triangular plate; 42. Third fixed plate; 43. Third limiting slide groove; 44. Pressure column; 45. First elastic member; 46. Second elastic member; 47. Second sliding sleeve; 48. Third elastic member; 49. Second telescopic rod; 50. Elastic ball. DETAILED DESCRIPTION

[0049] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0050] Example 1:

[0051] Key References Figure 1 、 Figure 2 and Figure 4The device mainly includes a raw liquid storage tank 2, a first-stage low-temperature evaporation and concentration equipment 3, a second-stage heat pump low-temperature flash equipment 4, and a third-stage reactor 5.

[0052] The raw liquid storage tank 2, the first-stage low-temperature evaporation and concentration equipment 3, the second-stage heat pump low-temperature flash equipment 4, and the third-stage reactor 5 are all fixedly installed on the frame 1, occupying a small area.

[0053] The raw liquid storage tank 2 is a device that uses low-temperature evaporation and concentration. Low-temperature evaporation and concentration equipment is a device that uses low-temperature evaporation and concentration. After the first evaporation and concentration, a large amount of water in the raw liquid is removed, and the distilled water is reused in other cooling processes.

[0054] Adopting the principle of heat pump compression, the heat medium is output at one end to evaporate the material, and the refrigerant is output at the other end to condense the steam. The heat pump compressor works to meet the heat and cold required for evaporative cooling at the same time, thereby reducing energy consumption. The energy consumption ratio is 1:7. At the same time, under high vacuum conditions, the material can be operated efficiently at low temperature (30-40 degrees).

[0055] The mother liquor concentrated by the first evaporation is subjected to the second-stage flash atomization in the first-stage low-temperature evaporation and concentration equipment 3 to remove trace water in the raw liquid, and the distilled water returns to the raw liquid storage tank.

[0056] Heat pump low-temperature flash evaporation equipment is a highly efficient evaporation device based on flash evaporation and heat pump technology. Flash evaporation involves rapidly reducing the pressure of a hot solution under a certain pressure, causing a portion of the solvent, typically water, to instantly vaporize at low temperatures. Heat pumps are used to increase and transfer heat, transferring it from a low-temperature location to a high-temperature location, where it can be reused to heat the solution and maintain the flash evaporation process.

[0057] The vacuum separation technology is used to atomize the solution in the distillation kettle to remove trace water;

[0058] The first-stage low-temperature evaporation and concentration equipment 3 includes an atomizer, a reactor, a separator, a coalescer, a vacuum chamber, a defoamer, an observation window, and a liquid level meter;

[0059] Atomizer: Atomizes the solution entering the vacuum separation system and sprays it onto the reactor;

[0060] Reactor: It is composed of multiple Raschig rings, which allow the solution sprayed onto the reactor to form a thin film, allowing the water and gas in the NMP solution to evaporate as much as possible, thereby improving the efficiency of dehydration and degassing;

[0061] Separation chamber: located between the reactor and the coalescer. When the solution runs in this area, water, gas, and NMP are separated again.

[0062] Coalescer; gathers the solution from which water and gas are separated;

[0063] Vacuum chamber: extract the water vapor and residual gas separated in the reactor and separation chamber from the vacuum separation system.

[0064] A transfer pipe 8 is connected between the raw liquid storage tank 2 and the first-stage low-temperature evaporation and concentration equipment 3. A pump body 7 is installed in the middle of the transfer pipe 8 to transfer the NMP recovery liquid in the raw liquid storage tank 2 to the first-stage low-temperature evaporation and concentration equipment 3 for the first removal of moisture.

[0065] A transfer pipe 8 is also connected between the first-stage low-temperature evaporation and concentration equipment 3 and the second-stage heat pump low-temperature flash evaporation equipment 4. A pump body 7 is installed in the middle of the transfer pipe 8 to transfer the NMP recovery liquid in the first-stage low-temperature evaporation and concentration equipment 3 to the second-stage heat pump low-temperature flash evaporation equipment 4 for a second water removal.

[0066] The third-stage reactor 5 is connected to a feed pipe 18, and a transfer pipe 8 is also connected between the second-stage heat pump low-temperature flash evaporation device 4 and the feed pipe 18. A pump body 7 is installed in the middle of the transfer pipe 8 for transferring the NMP recovery liquid in the second-stage heat pump low-temperature flash evaporation device 4 to the third-stage reactor 5 for distillation to obtain purified NMP.

[0067] A first cavity 6 is provided in the top shell of the third-stage reactor 5, and a steam inlet 34 connected to the first cavity 6 is provided on the top inner wall of the third-stage reactor 5. A refrigeration device 32 is provided in the first cavity 6. A discharge pipe 9 connected to the first cavity 6 is installed on the third-stage reactor 5. The refrigeration device 32 condenses the steam and purifies the NMP solution by distillation into the first cavity 6 to flow out from the discharge pipe 9 to obtain purified NMP.

[0068] A second cavity 19 is formed in the inner cavity of the bottom shell of the third-stage reactor 5 . The second cavity 19 is filled with hot kerosene medium, and an explosion-proof heating rod 20 is installed in the second cavity 19 .

[0069] Example 2: Based on Example 1, a technical means of removing the residual waste at the bottom of the third-stage reactor 5 and cleaning the interior of the third-stage reactor 5 is added.

[0070] Key References Figure 3-8 This embodiment mainly includes a first motor 30, a second motor 31, a spline shaft 35, a spline shaft sleeve 12, a threaded rod 38, a limiting slide 24, a second mounting plate 27, and a collecting shovel frame 29.

[0071] The third-stage reactor 5 is provided with a waste outlet 21, which is located on the bottom side wall of the third-stage reactor 5 and is used to allow the collection shovel frame 29 located at the bottom to be removed from the waste outlet 21. The third-stage reactor 5 is provided with a sealing door 11 that can block the waste outlet 21.

[0072] The spline shaft 35 is connected to the top of the third-stage reactor 5 for limited rotation, and the outer wall of the spline shaft 35 is connected to the spline sleeve 12 for limited sliding. The first motor 30 is fixedly installed on the top of the third-stage reactor 5, and the power output end of the first motor 30 is connected to the spline shaft 35. The bottom of the spline sleeve 12 is fixedly connected to the first fixed plate 13.

[0073] The inner top of the third-stage reactor 5 is connected to a threaded rod 38 for limited rotation, and a second fixed plate 33 is fixedly installed on the inner wall of the third-stage reactor 5. The threaded rod 38 is connected to the second fixed plate 33 for limited rotation. A second motor 31 is fixedly installed on the top of the third-stage reactor 5. The power output end of the second motor 31 is connected to the threaded rod 38. The outer wall of the threaded rod 38 is threadedly connected to a limited slide 39. The limited slide 39 is connected to the second limited slide groove 40 on the inner wall of the third-stage reactor 5 for limited sliding up and down movement. A connecting plate 37 is fixedly connected to the limiting slide 39, and a bearing seat 36 is fixedly installed on the connecting plate 37. The spline sleeve 12 is connected to the bearing seat 36 for limited rotation, so that the spline sleeve 12 can be raised and lowered.

[0074] The first telescopic rod 14 is fixedly connected to the bottom of the first fixed plate 13. The outer wall of the first telescopic rod 14 is limitedly slidably connected to the first sliding sleeve 22. The bottom of the first sliding sleeve 22 is fixedly connected to the top of the slide plate 16. The inner bottom of the first sliding sleeve 22 is fixedly connected to the second elastic member 46. The end of the second elastic member 46 away from the inner bottom of the first sliding sleeve 22 is fixedly connected to the first telescopic rod 14.

[0075] The slide rail plate 16 is connected to the limiting slide plate 24 for left and right limiting sliding through the first limiting slide groove 17 opened thereon. A hinged rod 15 is hinged between the first fixed plate 13 and the limiting slide plate 24. The outer wall of the limiting slide plate 24 near the bottom is rotatably connected to the first rotating column 28. The outer wall of the first rotating column 28 is fixedly connected to the second mounting plate 27. The bottom of one side of the second mounting plate 27 is fixedly connected to a collecting shovel frame 29.

[0076] It is understandable that the first telescopic rod 14 , the first sliding sleeve 22 , and the second elastic member 46 have a sufficient fitting distance, so that the collecting shovel frame 29 can be moved to the inner wall of the third-stage reactor 5 or even outside the third-stage reactor 5 .

[0077] The outer wall of the limiting slide 24 is fixedly connected to the first mounting plate 25, the second sliding sleeve 47 is fixedly connected to the bottom of the first mounting plate 25, the second sliding sleeve 47 is slidingly limited and connected to the second telescopic rod 49, the inner top of the second sliding sleeve 47 is fixedly connected to the third elastic member 48, the bottom of the third elastic member 48 is fixedly connected to the top of the second telescopic rod 49, and the bottom of the second telescopic rod 49 is fixedly installed with an elastic ball 50, which is squeezed against the top of the other side of the second mounting plate 27 to keep the collecting shovel frame 29 in a preset state to remove residual waste at the bottom of the third-stage reactor 5.

[0078] A waste collection frame 10 is detachably mounted on the outer wall of the third-stage reactor 5 for collecting residual waste shoveled out by the collection shovel frame 29 .

[0079] The limiting slide 24 is connected to a triangular plate 41 for upper and lower limiting sliding. A third fixed plate 42 is fixedly connected to the limiting slide 24. A third limiting slot 43 is provided on the third fixing plate 42. A pressure column 44 is connected to the third limiting slot 43 for upper and lower limiting sliding. The top of the pressure column 44 is fixedly connected to the bottom of the triangular plate 41. A first elastic member 45 is fixedly connected between the triangular plate 41 and the third fixed plate 42. The bottom of the pressure column 44 is pressed against the top of one side of the second mounting plate 27.

[0080] The wedge plate 23 is fixedly installed on the inner wall of the third-stage reactor 5, and the triangular plate 41 cooperates with the wedge plate 23 to move the pressure column 44 downward to tilt the collecting shovel frame 29 downward. After the collecting shovel frame 29 moves to the outside, the collecting shovel frame 29 is in an inclined state. When recovered, the collecting shovel frame 29 returns to its initial state and is stably retracted into the third-stage reactor 5.

[0081] The other structures are the same as those in the first embodiment.

[0082] Embodiment 3: Based on embodiment 2, a technical means is added to reduce the space occupied by the overall device.

[0083] Key References Figure 1 , mainly including framework 1.

[0084] The raw liquid storage tank 2, the first-stage low-temperature evaporation and concentration equipment 3, the second-stage heat pump low-temperature flash equipment 4, and the third-stage reactor 5 are all fixedly mounted on the frame 1, so that the devices are integrated together, thereby occupying a small space.

[0085] The other structures are the same as those in the second embodiment.

[0086] In this embodiment, the pump body 7 between the raw liquid storage tank 2 and the first-stage low-temperature evaporation and concentration equipment 3 is started to transfer the NMP recovery liquid in the raw liquid storage tank 2 to the first-stage low-temperature evaporation and concentration equipment 3 for the first distillation to remove the moisture of the NMP recovery liquid;

[0087] When the pump body 7 between the first-stage low-temperature evaporation and concentration device 3 and the second-stage heat pump low-temperature flash evaporation device 4 is started, the NMP recovery liquid after the first distillation in the first-stage low-temperature evaporation and concentration device 3 is transferred to the second-stage heat pump low-temperature flash evaporation device 4 to remove trace moisture therein again;

[0088] The pump body 7 between the second-stage heat pump low-temperature flash evaporation device 4 and the third-stage reactor 5 is started to transfer the NMP recovery liquid distilled in the second-stage heat pump low-temperature flash evaporation device 4 to the third-stage reactor 5. At this time, the power supply of the explosion-proof heating rod 20 is started to heat the hot kerosene medium in the second cavity 19, thereby heating and distilling the NMP recovery liquid in the third-stage reactor 5. At this time, the refrigeration device 32 is started to convert the NMP recovery liquid vapor into liquid, which is collected in the first cavity 6 and discharged from the discharge pipe 9 to obtain purified NMP;

[0089] When distilling the NMP recovery liquid in the third-stage reactor 5, the second motor 31 is started to move the bearing seat 36, the spline shaft sleeve 12, and the collecting shovel frame 29 up and down so that the collecting shovel frame 29 does not contact the bottom of the third-stage reactor 5, and then the first motor 30 is started to rotate the second mounting plate 27 and the collecting shovel frame 29 to stir, so that the NMP recovery liquid is better heated, thereby increasing the distillation speed;

[0090] At the end of distillation, the feed pipe 18 and the conveying pipe 8 can be removed and the cleaning liquid can be injected through the feed pipe 18. At this time, the second motor 31 is started to make the spline shaft sleeve 12 and the first fixed plate 13 descend to the preset position. At this time, the collecting shovel frame 29 is just placed on the inner bottom of the third-stage reactor 5. Then the second motor 31 is started again to make the spline shaft sleeve 12 and the first fixed plate 13 continue to move downward by a preset distance. At this time, the second elastic member 46 in the first sliding sleeve 22 is contracted. The collecting shovel frame 29 moves to one side at the bottom of the third-stage reactor 5 and moves to the side wall of the third-stage reactor 5, collecting the third-stage reactor 5. The residual waste at the bottom of the reactor 5 is shoveled into the collecting shovel frame 29, and then the second motor 31 is started to make the collecting shovel frame 29 return to the position just placed at the inner bottom of the third-stage reactor 5. At this time, the first motor 30 is started to make the collecting shovel frame 29 rotate a preset angle, and then the second motor 31 is started to make the spline shaft sleeve 12 and the first fixed plate 13 continue to move downward a preset distance. At this time, the collecting shovel frame 29 shovels the residual waste at another angle of the bottom of the third-stage reactor 5 into the collecting shovel frame 29. The above operation is repeated to shovel the residual waste at various positions of the bottom of the third-stage reactor 5 into the collecting shovel frame 29;

[0091] The sealing door 11 is opened, and the first motor 30 is started to make the collecting shovel frame 29 face the waste outlet 21. The second motor 31 is started to make the spline shaft sleeve 12 and the first fixed plate 13 descend a greater distance. At this time, the collecting shovel frame 29 moves from the waste outlet 21 to the outside of the third-stage reactor 5. Then, the triangular plate 41 and the wedge-shaped plate 23 cooperate with each other, so that the pressure column 44 squeezes the second mounting plate 27, making the collecting shovel frame 29 tilted, and pouring the waste into the waste collection frame 10, completing the waste shoveling at the bottom of the third-stage reactor 5;

[0092] Close the sealing door 11, remove the feed pipe 18 and the conveying pipe 8, and inject the cleaning liquid through the feed pipe 18. At this time, start the first motor 30 to make the second mounting plate 27 and the collecting shovel frame 29 stir the liquid in the third-stage reactor 5 to clean the inside of the third-stage reactor 5. Then, open the sealing door 11 to release the cleaning liquid, and then use the collecting shovel frame 29 to shovel out the bottom waste at the bottom of the third-stage reactor 5 and convey it to the outside, thereby completing the cleaning of the inside of the third-stage reactor 5.

[0093] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. NMP multi-stage distillation purification equipment, characterized in that, include: The third stage reactor (5); A first cavity (6) is provided in the top shell of the third-stage reactor (5); a steam inlet hole (34) communicating with the first cavity (6) is provided on the top inner wall of the third-stage reactor (5); a refrigeration device (32) is provided in the first cavity (6); a discharge pipe (9) communicating with the first cavity (6) is installed on the third-stage reactor (5) for distilling NMP into the first cavity (6) and flowing out from the discharge pipe (9) to obtain purified NMP; The third-stage reactor (5) is provided with a heating mechanism for heating NMP; The third-stage reaction kettle (5) is connected to a feed pipe (18), the third-stage reaction kettle (5) is provided with a waste outlet (21), and the third-stage reaction kettle (5) is provided with a sealing door (11) capable of sealing the waste outlet (21); The third-stage reactor (5) is provided with a collecting shovel frame (29), and the third-stage reactor (5) is provided with a driving mechanism, so that the collecting shovel frame (29) can move up and down, move left and right, and rotate, so that the collecting shovel frame (29) can shovel the residual waste at the bottom of the third-stage reactor (5) into the collecting shovel frame (29), and transfer the residual waste in the collecting shovel frame (29) from the waste outlet (21) to the outside of the third-stage reactor (5) for dumping, thereby realizing the waste removal operation. When NMP is distilled or the residual waste is prepared to be removed and cleaned, the collecting shovel frame (29) is stirred, thereby better distillation operation and better removal of residual waste are facilitated.

2. NMP multi-stage distillation purification equipment according to claim 1, is characterized in that, It also comprises a first-stage low-temperature evaporation and concentration device (3) and a raw liquid storage tank (2), wherein the first-stage low-temperature evaporation and concentration device (3) is connected to the raw liquid storage tank (2) via a liquid transmission mechanism, and the first-stage low-temperature evaporation and concentration device (3) is connected to a feed pipe (18) via the liquid transmission mechanism.

3. NMP multi-stage distillation purification equipment according to claim 2, is characterized in that, It also includes a second-stage heat pump low-temperature flash evaporation device (4), the first-stage low-temperature evaporation concentration device (3) is also connected to the second-stage heat pump low-temperature flash evaporation device (4) through a liquid transmission mechanism, and the second-stage heat pump low-temperature flash evaporation device (4) is connected to a feed pipe (18) through the liquid transmission mechanism.

4. NMP multi-stage distillation purification equipment according to claim 3, characterized in that, The liquid conveying mechanism comprises a conveying pipe (8), a pump body (7) being installed in the middle of the conveying pipe (8) so as to enable one end of the conveying pipe (8) to absorb liquid and the other end to discharge liquid. One end of the conveying pipe (8) is in communication with a liquid outlet of a raw liquid storage tank (2) or a liquid outlet of a first-stage low-temperature evaporation and concentration device (3) or a liquid outlet of a second-stage heat pump low-temperature flash evaporation device (4), and the other end of the conveying pipe (8) is in communication with a liquid inlet of the first-stage low-temperature evaporation and concentration device (3) or a liquid inlet of a second-stage heat pump low-temperature flash evaporation device (4) or the conveying pipe (8).

5. NMP multi-stage distillation purification equipment according to claim 1, characterized in that, The heating mechanism comprises an explosion-proof heating rod (20); a second cavity (19) is provided in the inner cavity of the bottom shell of the third-stage reactor (5); the second cavity (19) is filled with hot kerosene medium; and the explosion-proof heating rod (20) is installed in the second cavity (19).

6. NMP multi-stage distillation purification equipment according to claim 1, characterized in that, The driving mechanism comprises a spline shaft (35), the spline shaft (35) is limitedly rotatably connected to the top of the third-stage reactor (5), the outer wall of the spline shaft (35) is limitedly slidably connected to a spline shaft sleeve (12), a first motor (30) is fixedly installed on the top of the third-stage reactor (5), a power output end of the first motor (30) is connected to the spline shaft (35), a first fixing plate (13) is fixedly connected to the bottom of the spline shaft sleeve (12), and a lifting mechanism is arranged on the spline shaft sleeve (12); The first fixed plate (13) is connected to a slide rail plate (16) through an auxiliary elastic telescopic mechanism, and the slide rail plate (16) is slidably connected to a limit slide plate (24) through a first limit slide groove (17) provided thereon, and a hinge rod (15) is hinged between the first fixed plate (13) and the limit slide plate (24), and the limit slide plate (24) is rotatably connected to a first rotating column (28) at an outer wall near the bottom, and the outer wall of the first rotating column (28) is fixedly connected to a second mounting plate (27), and a collecting shovel frame (29) is fixedly connected to the bottom of one side of the second mounting plate (27); The outer wall of the limiting slide plate (24) is fixedly connected to a first mounting plate (25), and the first mounting plate (25) is pressed on the top of the other side of the second mounting plate (27) through an elastic telescopic rod (26), so as to keep the collecting shovel frame (29) in a preset state to shovel residual waste at the bottom of the third-stage reactor (5); The outer wall of the third-stage reaction kettle (5) is detachably provided with a waste collection frame (10) for collecting residual waste shoveled out by the collection shovel frame (29); The third-stage reactor (5) is provided with a dumping mechanism which enables the collecting shovel frame (29) to be in an inclined state after being moved out of the waste outlet (21) to the outside of the third-stage reactor (5).

7. The NMP multi-stage distillation purification equipment according to claim 6, characterized in that, The lifting mechanism comprises a threaded rod (38), the inner top of the third-stage reactor (5) is connected to the threaded rod (38) in a limited rotational manner, the inner wall of the third-stage reactor (5) is fixedly mounted with a second fixed plate (33), the threaded rod (38) is connected to the second fixed plate (33) in a limited rotational manner, the top of the third-stage reactor (5) is fixedly mounted with a second motor (31), the power output end of the second motor (31) is connected to the threaded rod (38), the outer wall of the threaded rod (38) is threadedly connected with a limited sliding bar (39), the limited sliding bar (39) is connected to the second limited sliding groove (40) of the inner wall of the third-stage reactor (5) in a limited upward and downward sliding manner, the limited sliding bar (39) is fixedly connected with a connecting plate (37), the connecting plate (37) is fixedly mounted with a bearing seat (36), and the spline shaft sleeve (12) is connected to the bearing seat (36) in a limited rotational manner.

8. The NMP multi-stage distillation purification equipment according to claim 7, characterized in that, The auxiliary elastic telescopic mechanism comprises a first telescopic rod (14) and a first sliding sleeve (22); the bottom of the first fixed plate (13) is fixedly connected to the first telescopic rod (14); the outer wall of the first telescopic rod (14) is limitedly slidably connected to the first sliding sleeve (22); the bottom of the first sliding sleeve (22) is fixedly connected to the top of the slide rail plate (16); the inner bottom of the first sliding sleeve (22) is fixedly connected to the second elastic member (46); one end of the second elastic member (46) away from the inner bottom of the first sliding sleeve (22) is fixedly connected to the first telescopic rod (14); The retractable rod (26) comprises a second sliding sleeve (47) and a second telescopic rod (49); the second sliding sleeve (47) is fixedly connected to the bottom of the first mounting plate (25); the second telescopic rod (49) is slidably connected to the inside of the second sliding sleeve (47); the inner top of the second sliding sleeve (47) is fixedly connected to a third elastic member (48); the bottom of the third elastic member (48) is fixedly connected to the top of the second telescopic rod (49); an elastic ball (50) is fixedly installed at the bottom of the second telescopic rod (49); and the elastic ball (50) is pressed against the top of the second mounting plate (27).

9. The NMP multi-stage distillation purification equipment according to claim 8, characterized in that, The tipping mechanism comprises a triangular plate (41), the limiting slide plate (24) is connected to the triangular plate (41) in an upper and lower limiting sliding manner, the limiting slide plate (24) is fixedly connected to a third fixed plate (42), the third fixed plate (42) is provided with a third limiting sliding groove (43), the third limiting sliding groove (43) is connected to a pressure column (44) in an upper and lower limiting sliding manner, the top of the pressure column (44) is fixedly connected to the bottom of the triangular plate (41), a first elastic member (45) is fixedly connected between the triangular plate (41) and the third fixed plate (42), and the bottom of the pressure column (44) is pressed against the top of one side of the second mounting plate (27); It also includes a wedge plate (23) which is fixedly mounted on the inner wall of the third-stage reactor (5). The triangular plate (41) cooperates with the wedge plate (23) to enable the pressure column (44) to move downward and tilt the collecting shovel frame (29) downward. 10.NMP multi-stage distillation purification process, characterized in that, The NMP multi-stage distillation purification equipment as claimed in claim 9 comprises: S1: starting the pump body (7) between the stock liquid storage tank (2) and the first-stage low-temperature evaporation and concentration device (3) to transfer the NMP recovery liquid in the stock liquid storage tank (2) to the first-stage low-temperature evaporation and concentration device (3) for the first distillation to remove the moisture in the NMP recovery liquid; S2: starting the pump body (7) between the first-stage low-temperature evaporation concentration device (3) and the second-stage heat pump low-temperature flash evaporation device (4) to transfer the NMP recovery liquid after the first distillation in the first-stage low-temperature evaporation concentration device (3) to the second-stage heat pump low-temperature flash evaporation device (4) to remove trace moisture therein again; S3: starting the pump body (7) between the second-stage heat pump low-temperature flash evaporation device (4) and the third-stage reactor (5) to transfer the NMP recovery liquid after distillation in the second-stage heat pump low-temperature flash evaporation device (4) to the third-stage reactor (5), and then starting the power supply of the explosion-proof heating rod (20) to heat the hot kerosene medium in the second cavity (19), so that the NMP recovery liquid in the third-stage reactor (5) is heated and distilled, and then starting the refrigeration device (32) to convert the NMP recovery liquid vapor into liquid and collect it in the first cavity (6) and discharge it from the discharge pipe (9) to obtain purified NMP; S4: When distilling the NMP recovery liquid in the third-stage reaction kettle (5), the second motor (31) is started to move the bearing seat (36), the spline shaft sleeve (12), and the collecting shovel frame (29) up and down, so that the collecting shovel frame (29) does not contact the bottom of the third-stage reaction kettle (5), and then the first motor (30) is started to rotate the second mounting plate (27) and the collecting shovel frame (29) for stirring, so that the NMP recovery liquid is better heated, thereby increasing the distillation speed; S5: At the end of distillation, the feed pipe (18) and the conveying pipe (8) can be removed and the cleaning liquid can be injected through the feed pipe (18). At this time, the second motor (31) is started to make the spline shaft sleeve (12) and the first fixed plate (13) descend to a preset position. At this time, the collecting shovel frame (29) is just placed on the inner bottom of the third-stage reactor (5). Then the second motor (31) is started again to make the spline shaft sleeve (12) and the first fixed plate (13) continue to move downward by a preset distance. At this time, the second elastic member (46) in the first sliding sleeve (22) is contracted, and the collecting shovel frame (29) moves to one side at the inner bottom of the third-stage reactor (5) and moves to the side wall of the third-stage reactor (5). The residual waste at the bottom of the third-stage reactor (5) is shoveled into the collecting shovel frame (29), and then the second motor (31) is started to make the collecting shovel frame (29) return to the position just placed at the inner bottom of the third-stage reactor (5). At this time, the first motor (30) is started to make the collecting shovel frame (29) rotate a preset angle, and then the second motor (31) is started to make the spline shaft sleeve (12) and the first fixed plate (13) continue to move downward a preset distance. At this time, the collecting shovel frame (29) shovels the residual waste at another angle of the inner bottom of the third-stage reactor (5) into the collecting shovel frame (29), and the above operation is repeated to shovel the residual waste at various positions of the inner bottom of the third-stage reactor (5) into the collecting shovel frame (29); S6: Open the sealing door (11), start the first motor (30) to make the collecting shovel frame (29) face the waste outlet (21), start the second motor (31) to make the spline shaft sleeve (12) and the first fixed plate (13) drop a greater distance, and then the collecting shovel frame (29) moves from the waste outlet (21) to the outside of the third-stage reactor (5), and then the triangular plate (41) and the wedge plate (23) cooperate with each other, so that the pressure column (44) squeezes the second mounting plate (27), so that the collecting shovel frame (29) is in an inclined state, and the waste is poured into the waste collection frame (10), and the waste at the bottom of the third-stage reactor (5) is shoveled; S7: The sealing door (11) is closed, and the feed pipe (18) and the conveying pipe (8) are removed and the cleaning liquid is injected through the feed pipe (18). At this time, the first motor (30) is started to make the second mounting plate (27) and the collecting shovel frame (29) stir the liquid in the third-stage reactor (5) to clean the inside of the third-stage reactor (5). Then, the sealing door (11) is opened to release the cleaning liquid, and the bottom waste at the bottom of the third-stage reactor (5) is shoveled out through the collecting shovel frame (29) and conveyed to the outside, thereby completing the cleaning of the inside of the third-stage reactor (5).

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