Process for separating amines from nmp recovery liquid

Abstract

This invention relates to the field of recovered liquid treatment technology, and discloses a process for separating amines from NMP recovered liquid, comprising the following steps: Step S1: The NMP regenerated liquid is injected into a dehydration tower in a purification device for dehydration distillation; Step S2: The dehydrated NMP regenerated liquid is injected into a distillation device for secondary dehydration distillation; Step S3: The water and light components such as amines separated in the distillation device are collected using a side-collection method; the distillation device includes a distillation tower, which has multiple sets of packing materials fixedly installed inside and a feed pipe connected to the side of the distillation tower. The beneficial effects of this invention are: it allows the solution in the middle of the collection pan to enter the area between the two sets of separating rings in the side-collection pipe, reducing the probability of sediment and floating matter entering the side-collection pipe; simultaneously, the solution being extracted is in an isolated state, improving the purity of the extracted solution.

Description

Technical Field

[0001] This invention relates to the field of recovery liquid treatment technology, and specifically to a process for separating amines from NMP recovery liquid. Background Technology

[0002] NMP recovery solution refers to a mixed solution containing large amounts of NMP, impurities, and dissolved substances generated during the production process using N-methylpyrrolidone as a solvent or cleaning agent. After collection and preliminary treatment, these solutions are fed into an NMP recovery system for purification and regeneration, with the aim of obtaining pure NMP usable in production.

[0003] NMP recovery solution contains amines, which can be recycled or used as chemical raw materials and have significant economic value. Therefore, it is necessary to separate the amines from the NMP recovery solution. However, existing separation equipment is difficult to extract a relatively pure amine solution, which leads to the need for multiple subsequent processing steps and reduces the efficiency of amine extraction. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a separation process for amines in NMP recovery solutions, thereby achieving a better separation effect.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A process for separating amines from NMP recovery solution, comprising the following steps:

[0007] Step S1: The NMP regenerated solution is injected into the dehydration tower in the purification unit for dehydration and distillation;

[0008] Step S2: The dehydrated NMP regenerated solution is injected into the distillation equipment for secondary dehydration and distillation;

[0009] Step S3: Use a side-collection method to collect the light components such as water and amines separated in the distillation equipment;

[0010] The distillation equipment includes a distillation column, which has multiple sets of packing material fixedly installed inside and a feed pipe connected to the side of the distillation column. A liquid collecting tray, a liquid distributor, and a gas distributor are fixedly installed between the packing material. Multiple sets of riser pipes are connected inside the liquid collecting tray. The riser pipes pass through the liquid collecting tray and a cap is fixedly installed at the end of the riser pipe. The cap is spaced from the end of the riser pipe. A drain pipe is connected to the lower surface of the liquid collecting tray.

[0011] Multiple sets of side collection pipes are fixedly installed in the liquid collection tray near the top packing. Each side collection pipe has a notch on one side and two sets of spaced-apart partition rings are fixedly installed inside. A vertical rod passes through the two partition rings inside the side collection pipe. Two sets of sealing plates for closing the corresponding partition rings are fixedly installed on the vertical rod. A second support plate is fixedly installed on each partition ring. A cover plate for closing the notch on the side collection pipe is slidably installed on the second support plate. When the cover plate contacts the side collection pipe, it contacts the partition ring. An electric telescopic rod is fixedly installed on the upper side wall of the distillation column. A horizontal plate is fixedly installed at the output end of the electric telescopic rod. Multiple sets of connecting plates are fixedly installed on the horizontal plate, and the connecting plates are fixedly connected to the corresponding cover plates. A power plate for pushing the vertical rod upwards is rotatably installed inside the side collection pipe. A pumping branch pipe is connected to the side collection pipe, and the connection point between the pumping branch pipe and the side collection pipe is located between the two sets of partition rings. Multiple pumping branch pipes are connected to a main pumping pipe, which is connected to a first water pump located outside the distillation column.

[0012] Preferably, two sets of first support plates are fixedly installed inside the side sampling pipe. The two sets of first support plates are distributed on both sides of the two sets of separator rings, and the vertical rod is slidably installed on the first support plate and passes through the first support plate.

[0013] Preferably, a filter cover covering its internal hole is fixedly installed on the partition ring, a vertical rod passes through the filter cover and slides in contact with the filter cover, and an arc-shaped filter plate is fixedly installed on both sets of partition rings, and the filter plate is fixedly connected to the side wall of the side sampling pipe.

[0014] Preferably, a piston cylinder is fixedly installed on the partition ring located above the side sampling pipe. When the sealing plate moves upward and enters the piston cylinder, it pushes the liquid inside the piston cylinder to flow upward.

[0015] Preferably, the power plate is rotatably installed inside the side sampling pipe via a support rod. A third support plate is fixedly installed at the lower end of the vertical rod, which contacts the end of the power plate. The support rod is close to the side of the power plate that contacts the third support plate. In the initial state, the end of the power plate away from the third support plate is lower and the lower end of the power plate contacts the cover plate. When the cover plate contacts the side sampling pipe, the cover plate and the partition ring together seal the area where the filter plate is located, and there is a gap between the filter plate and the cover plate.

[0016] Preferably, the outlet of the first water pump is connected to a flow stabilizer box located on the side wall of the distillation column. Two sets of partitions are fixedly installed inside the flow stabilizer box, and through holes are opened on the partitions. A liquid level sensor is fixedly installed at the bottom of the flow stabilizer box, and a second water pump is fixedly installed on the flow stabilizer box. The inlet of the second water pump extends into the bottom of the flow stabilizer box.

[0017] Preferably, multiple sets of guide rods are fixedly installed on the lower partition, and floats are slidably installed on the guide rods, with the floats corresponding to the through holes on the upper partition.

[0018] The beneficial effects of this invention are:

[0019] (1) In this invention, when the cover plate is far away from the side collection pipe, the solution in the collection plate enters the side collection pipe. Due to the setting of the separator ring, a large amount of solution in the middle of the collection plate enters the area between the two sets of separator rings in the side collection pipe, which reduces the probability of bottom sediment and upper floating matter entering the side collection pipe and improves the purity of the extracted solution. At the same time, the solution being extracted is in an isolated state, so the liquid outside the side collection pipe will not flow into the side collection pipe during extraction, further improving the purity of the extracted solution.

[0020] (2) In this invention, when the liquid enters the area between the two sets of partition rings in the side sampling pipe, the liquid is filtered by the filter cover and filter plate, thereby further improving the purity of the liquid in the side sampling pipe. When the sealing plate moves upward to close the partition ring, the sealing plate enters the piston cylinder and pushes the liquid in the piston cylinder to flow upward, thereby backwashing the filter cover above by the upward flowing liquid. When the sealing plate moves downward to push the liquid below it to flow, the filter cover below is backwashed, avoiding the accumulation of impurities on the filter cover and further improving the purity of the side sampling liquid. At the same time, when the cover plate leaves the side sampling pipe quickly, the liquid behind the cover plate will follow the cover plate, thereby flushing away the impurities on the filter plate, avoiding filter plate blockage and improving the filtration effect.

[0021] (3) In this invention, when the liquid level sensor detects that the liquid level height is a stable value and is the same as the height of the lower surface of the upper partition, it indicates that the flow stabilizing tank is full of liquid. At this time, the float will close the through hole on the upper partition. At this time, the liquid in the flow stabilizing tank is pumped out by the second water pump. When the liquid below the partition decreases, the float moves downward. At this time, the liquid above the partition can flow downward to replenish it, thereby making the float float up and down near the upper partition and intermittently close the through hole on the upper partition. Thus, when the liquid on the upper partition vibrates and agitates, it is difficult to transmit to the solution below, thereby improving the stability of the solution pumped by the second water pump and enabling the second water pump to stably deliver the solution, ensuring the subsequent stable treatment of the solution. Attached Figure Description

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the internal structure of the distillation tower in this invention.

[0025] Figure 3 This is a first-view structural schematic diagram of the liquid collection tray in this invention.

[0026] Figure 4 This is a second-view structural schematic diagram of the liquid collection tray in this invention.

[0027] Figure 5 This is a schematic diagram of the horizontal plate in this invention.

[0028] Figure 6 This is a schematic diagram of the side sampling pipe in this invention.

[0029] Figure 7 This is a cross-sectional view of the side sampling pipe in this invention.

[0030] Figure 8 This is a schematic diagram of the current stabilizing box structure in this invention.

[0031] Figure 9 yes Figure 7 Enlarged schematic diagram of point A1 in the middle.

[0032] Figure 10 yes Figure 7 Enlarged diagram of point A2 in the middle.

[0033] In the diagram: 1. Distillation column; 2. Feed pipe; 3. Packing; 4. Liquid collecting tray; 5. Liquid distributor; 6. Gas distributor; 7. Upflow pipe; 8. Cap; 9. Side sampling pipe; 10. Flow stabilizing box; 11. Separating ring; 12. First support plate; 13. Vertical rod; 14. Sealing plate; 15. Filter cover; 16. Second support plate; 17. Cover plate; 18. Piston cylinder; 19. Filter plate; 20. Through hole; 21. Third support plate; 22. Power plate; 23. Liquid level sensor; 24. Connecting plate; 25. Horizontal plate; 26. Electric telescopic rod; 27. Pumping branch pipe; 28. Pumping main pipe; 29. ​​First water pump; 30. Second water pump; 31. Baffle plate; 32. Guide rod; 33. Float plate; 34. Drain pipe. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1-10 As shown, this invention provides a process for separating amines from NMP recovery liquid, which includes the following steps:

[0036] Step S1: The NMP regenerated solution is injected into the dehydration tower in the purification unit for dehydration and distillation;

[0037] Step S2: The dehydrated NMP regenerated solution is injected into the distillation equipment for secondary dehydration and distillation;

[0038] Step S3: Use a side sampling method to extract the light components such as water and amines separated in the distillation equipment.

[0039] The distillation equipment includes a distillation column 1, which has multiple sets of packing 3 fixedly installed inside and a feed pipe 2 connected to the side of the distillation column 1. A liquid collecting tray 4, a liquid distributor 5, and a gas distributor 6 are fixedly installed between the packing 3. Multiple sets of riser pipes 7 are connected inside the liquid collecting tray 4. The riser pipes 7 pass through the liquid collecting tray 4 and a cap 8 is fixedly installed at the end of the riser pipe 7. The cap 8 is spaced from the end of the riser pipe 7. A drain pipe 34 is connected to the lower surface of the liquid collecting tray 4.

[0040] Multiple sets of side sampling pipes 9 are fixedly installed inside the liquid collection tray 4 near the uppermost packing 3. Each side sampling pipe 9 has a notch on one side and two sets of spaced-apart partition rings 11 are fixedly installed inside it. A vertical rod 13 passes through the two partition rings 11 inside the side sampling pipe 9. Two sets of sealing plates 14 for closing the corresponding partition rings 11 are fixedly installed on the vertical rod 13. Two sets of first support plates 12 are fixedly installed inside the side sampling pipe 9, located on either side of the two partition rings 11. The vertical rod 13 is slidably mounted on the first support plate 12 and passes through it. A second support plate 16 is fixedly installed on the partition rings 11, and a device for closing the side sampling pipe 9 is slidably mounted on the second support plate 16. The cover plate 17 with an upper notch contacts the side sampling pipe 9 and the separation ring 11. An electric telescopic rod 26 is fixedly installed on the upper side wall of the distillation column 1. A horizontal plate 25 is fixedly installed at the output end of the electric telescopic rod 26. Multiple sets of connecting plates 24 are fixedly installed on the horizontal plate 25. The connecting plates 24 are fixedly connected to the corresponding cover plate 17. A power plate 22 for pushing the vertical rod 13 upward is rotatably installed inside the side sampling pipe 9. A water pumping branch pipe 27 is connected to the side sampling pipe 9, and the connection position between the water pumping branch pipe 27 and the side sampling pipe 9 is between the two sets of separation rings 11. Multiple sets of water pumping branch pipes 27 are connected to the main water pumping pipe 28. The main water pumping pipe 28 is connected to the first water pump 29 located outside the distillation column 1.

[0041] In practical application, the dehydrated NMP regenerated liquid is injected into the distillation tower 1 through the feed pipe 2 for distillation. The distillation tower 1 is equipped with 5 packings 3. The feed pipe 2 is located between the second and third packings 3 at the bottom. After distillation, the liquid formed by water and light components such as amines falls into the collection pan 4. The vapor passes upward through the riser pipe 7 and through the collection pan 4. The cap 8 prevents the falling liquid from passing directly through the riser pipe 7. The liquid at the bottom of the collection pan 4 flows downward through the drain pipe 34 to the liquid distributor 5.

[0042] Initially, the cover plate 17 is away from the side collection pipe 9, and the separating ring 11 is open. When liquid accumulates on the collection pan 4, the side collection pipe 9 is filled with liquid. After the liquid on the collection pan 4 reaches a stable state, side collection is performed. During side collection, the electric telescopic rod 26 retracts, causing the horizontal plate 25 to move. The horizontal plate 25, through the connecting plate 24, moves the cover plate 17 closer until it contacts the side wall of the side collection pipe 9. At this time, the opening of the side collection pipe 9 is closed. When the cover plate 17 moves closer to the side collection pipe 9, the power plate 22 causes the vertical rod 13 to move upward. When the cover plate 17 contacts the side collection pipe 9, the sealing plate 14 contacts the upper separating ring 11. At this time, the liquid between the two sets of separating rings 11 is isolated. Then, the first water pump 29 passes through... The main pumping pipe 28 and the branch pumping pipe 27 extract the isolated liquid. After extraction, the first pump 29 stops working. Then, the cover plate 17 moves away from the side collection pipe 9. At this time, the solution in the collection tray 4 can re-enter the side collection pipe 9. Due to the setting of the separator ring 11, a large amount of solution in the middle of the collection tray 4 enters the area between the two sets of separator rings 11 in the side collection pipe 9, reducing the probability of bottom sediment and upper floating matter entering the side collection pipe 9, and improving the purity of the extracted solution. At the same time, the extracted solution is in an isolated state when extracting the solution, so that the liquid outside the side collection pipe 9 will not flow into the side collection pipe 9 during extraction, further improving the purity of the extracted solution. Repeat the above steps to complete the side collection of the amine-containing solution.

[0043] Please see Figure 7 , Figure 9 , Figure 10 As shown, the present invention is a separation process for amines in NMP recovery liquid. A filter cover 15 covering its internal holes is fixedly installed on the separator ring 11. A vertical rod 13 passes through the filter cover 15 and slides in contact with the filter cover 15. An arc-shaped filter plate 19 is fixedly installed on both sets of separator rings 11. The filter plate 19 is fixedly connected to the side wall of the side sampling pipe 9.

[0044] A piston cylinder 18 is fixedly installed on the partition ring 11 located above the side sampling pipe 9. When the sealing plate 14 moves upward and enters the piston cylinder 18, it pushes the liquid inside the piston cylinder 18 to flow upward.

[0045] The power plate 22 is rotatably installed inside the side sampling pipe 9 via a support rod. The lower end of the vertical rod 13 is fixedly installed with a third support plate 21 that contacts the end of the power plate 22. The support rod is close to the side of the power plate 22 that contacts the third support plate 21. In the initial state, the end of the power plate 22 away from the third support plate 21 is lower and the lower end of the power plate 22 contacts the cover plate 17. When the cover plate 17 contacts the side sampling pipe 9, the cover plate 17 and the partition ring 11 together seal the area where the filter plate 19 is located, and there is a gap between the filter plate 19 and the cover plate 17.

[0046] In practical application, when the cover plate 17 moves closer to the side sampling pipe 9, it pushes the power plate 22 to rotate. When the power plate 22 rotates, it pushes the vertical rod 13 upward through the third support plate 21, so that the sealing plate 14 contacts the separating ring 11 to achieve isolation. When the liquid enters the area between the two sets of separating rings 11 in the side sampling pipe 9, the liquid is filtered by the filter cover 15 and the filter plate 19, thereby further improving the purity of the liquid in the side sampling pipe 9. When the sealing plate 14 moves upward to close the separating ring 11, the sealing plate 14 enters the piston cylinder 18 and pushes the liquid in the piston cylinder 18 to flow upward, thereby backwashing the filter cover 15 above through the upward flowing liquid. When the sealing plate 14 moves downward, it pushes the liquid below it to flow, thereby achieving backwashing of the filter cover 15 below, avoiding the accumulation of impurities on the filter cover 15, and further improving the purity of the side sampling liquid.

[0047] When the cover plate 17 contacts the side sampling pipe 9, the cover plate 17 and the partition ring 11 together seal the area where the filter plate 19 is located, and there is a gap between the filter plate 19 and the cover plate 17, thereby preventing the cover plate 17 from squeezing the impurities on the filter plate 19. Subsequently, the cover plate 17 quickly leaves the side sampling pipe 9. At this time, the liquid behind the cover plate 17 will move with the cover plate 17, thereby flushing away the impurities on the filter plate 19, preventing the filter plate 19 from clogging and improving the filtration effect.

[0048] Please see Figure 2 , Figure 8 As shown, the outlet of the first water pump 29 is connected to a flow stabilizer 10 located on the side wall of the distillation column 1. Two sets of partitions 31 are fixedly installed inside the flow stabilizer 10. Through holes 20 are opened on the partitions 31. A liquid level sensor 23 is fixedly installed at the bottom of the flow stabilizer 10. A second water pump 30 is fixedly installed on the flow stabilizer 10. The inlet of the second water pump 30 extends into the bottom of the flow stabilizer 10.

[0049] Multiple sets of guide rods 32 are fixedly installed on the lower partition 31. A float 33 is slidably installed on the guide rod 32. The float 33 corresponds to the position of the through hole 20 on the upper partition 31.

[0050] In practical application, the liquid pumped by the first water pump 29 is delivered to the flow stabilizing tank 10. The liquid falls onto the upper partition 31 and then flows downward through the through hole 20. Eventually, the liquid level in the flow stabilizing tank 10 gradually rises. When the liquid level sensor 23 detects a stable liquid level that is the same as the lower surface of the upper partition 31, it indicates that the flow stabilizing tank 10 is full of liquid. At this time, the float plate 33 will close the through hole 20 on the upper partition 31. Then, the second water pump 30 pumps liquid from the flow stabilizing tank 10. When the liquid below the partition 31 decreases, the float plate 33 moves downward, allowing the liquid above the partition 31 to flow downward to replenish it. This causes the float plate 33 to float up and down near the upper partition 31 and intermittently close the through hole 20 on the upper partition 31. As a result, the liquid on the upper partition 31 is less likely to vibrate and agitate and be transmitted to the solution below, improving the stability of the solution pumped by the second water pump 30. This allows the second water pump 30 to stably deliver the solution and ensures stable subsequent processing of the solution.

[0051] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A process for separating amines from an NMP recovery solution, characterized in that, It includes the following steps: Step S1: The NMP regenerated solution is injected into the dehydration tower in the purification unit for dehydration and distillation; Step S2: The dehydrated NMP regenerated solution is injected into the distillation equipment for secondary dehydration and distillation; Step S3: Use a side-collection method to collect the light components such as water and amines separated in the distillation equipment; The distillation equipment includes a distillation column (1), in which multiple sets of packing (3) are fixedly installed and a feed pipe (2) is connected to the side of the distillation column (1). A liquid collection tray (4), a liquid distributor (5) and a gas distributor (6) are fixedly installed between the packing (3). Multiple sets of riser pipes (7) are connected inside the liquid collection tray (4). The riser pipes (7) pass through the liquid collection tray (4) and a cap (8) is fixedly installed at the end of the riser pipe (7). The cap (8) is spaced from the end of the riser pipe (7). A drain pipe (34) is connected to the lower surface of the liquid collection tray (4). Multiple sets of side sampling pipes (9) are fixedly installed in the liquid collection tray (4) near the topmost packing material (3). Each side sampling pipe (9) has a notch on one side and two sets of spaced-apart partition rings (11) are fixedly installed inside. A vertical rod (13) passes through the two sets of partition rings (11) inside the side sampling pipe (9). Two sets of sealing plates (14) for closing the corresponding partition rings (11) are fixedly installed on the vertical rods (13). A second support plate (16) is fixedly installed on each partition ring (11). A cover plate (17) for closing the notch on the side sampling pipe (9) is slidably installed on the second support plate (16). When the cover plate (17) contacts the side sampling pipe (9), the cover plate (17) contacts the partition ring (11). An electric telescopic rod (26) is fixedly installed on the upper side wall of the distillation column (1). A horizontal plate (25) is fixedly installed at the output end of the electric telescopic rod (26). Multiple sets of connecting plates (24) are fixedly installed on the horizontal plate (25). The connecting plate (24) is fixedly connected to the corresponding cover plate (17). A power plate (22) for pushing the vertical rod (13) to move upward is rotatably installed inside the side sampling pipe (9). A water pumping branch pipe (27) is connected to the side sampling pipe (9), and the connection position of the water pumping branch pipe (27) and the side sampling pipe (9) is located between the two sets of the separating rings (11). Multiple sets of the water pumping branch pipes (27) are connected to the main water pumping pipe (28). The main water pumping pipe (28) is connected to the first water pump (29) located outside the distillation column (1).

2. The process for separating amines from NMP recovery solution according to claim 1, characterized in that, Two sets of first support plates (12) are fixedly installed inside the side sampling pipe (9). The two sets of first support plates (12) are distributed on both sides of the two sets of separation rings (11). The vertical rod (13) is slidably installed on the first support plate (12) and the vertical rod (13) passes through the first support plate (12).

3. The process for separating amines from NMP recovery solution according to claim 1, characterized in that, A filter cover (15) covering its internal hole is fixedly installed on the partition ring (11). The vertical rod (13) passes through the filter cover (15) and slides in contact with the filter cover (15). The two sets of partition rings (11) are jointly fixedly installed with an arc-shaped filter plate (19). The filter plate (19) is fixedly connected to the side wall of the side sampling pipe (9).

4. The process for separating amines from NMP recovery solution according to claim 1, characterized in that, A piston cylinder (18) is fixedly installed on the partition ring (11) located above the side sampling pipe (9). When the sealing plate (14) moves upward into the piston cylinder (18), it pushes the liquid in the piston cylinder (18) to flow upward.

5. The process for separating amines from NMP recovery solution according to claim 3, characterized in that, The power plate (22) is rotatably installed inside the side sampling pipe (9) via a support rod. The lower end of the vertical rod (13) is fixedly installed with a third support plate (21) that contacts the end of the power plate (22). The support rod is close to the side of the power plate (22) that contacts the third support plate (21). In the initial state, the end of the power plate (22) away from the third support plate (21) is lower and the lower end of the power plate (22) contacts the cover plate (17). When the cover plate (17) contacts the side sampling pipe (9), the cover plate (17) and the partition ring (11) jointly seal the area where the filter plate (19) is located, and the filter plate (19) and the cover plate (17) are spaced apart.

6. The process for separating amines from NMP recovery solution according to claim 1, characterized in that, The outlet of the first water pump (29) is connected to a flow stabilizer (10) located on the side wall of the distillation column (1). Two sets of partitions (31) are fixedly installed inside the flow stabilizer (10). Through holes (20) are opened on the partitions (31). A liquid level sensor (23) is fixedly installed at the bottom of the flow stabilizer (10). A second water pump (30) is fixedly installed on the flow stabilizer (10). The inlet of the second water pump (30) extends into the bottom of the flow stabilizer (10).

7. The process for separating amines from NMP recovery solution according to claim 6, characterized in that, Multiple sets of guide rods (32) are fixedly installed on the lower partition (31), and floats (33) are slidably installed on the guide rods (32). The floats (33) correspond to the through holes (20) on the upper partition (31).

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