A device for the recovery, distillation and purification of NMP waste liquid

Abstract

This utility model relates to the field of distillation separation technology and discloses an NMP waste liquid recovery and distillation purification device, including a distillation buffer tank, a distillation column feed pump, a permeate condenser, a permeate buffer tank, and a permeate pump. A discharge pipe is fixedly connected to the outside of the distillation buffer tank, and the end of the discharge pipe away from the distillation buffer tank is fixedly connected to the input end of the distillation column feed pump. The output end of the distillation column feed pump is fixedly connected to the outside of the distillation column. The permeate condenser is connected to the distillation column and the permeate buffer tank. This utility model employs a forced circulation reboiler, which drives the material to circulate at high speed through a pump, improving the heat transfer coefficient, reducing heat source consumption, and eliminating the need for azeotropic agents, thus reducing energy consumption and saving costs. It also avoids secondary pollution and cools the high-temperature waste liquid generated during the distillation process, achieving environmentally friendly emissions.

Description

Technical Field

[0001] This utility model relates to the field of distillation and separation technology, and in particular to an NMP waste liquid recovery, distillation and purification device. Background Technology

[0002] NMP is a commonly used organic solvent, a colorless, transparent, oily liquid with a slight amine odor. Methylpyrrolidone has low volatility and good solubility and thermal stability. However, during use, NMP gradually becomes contaminated with impurities and turns into waste liquid, which not only wastes resources but also has adverse effects on the environment. NMP waste liquid can be recycled and treated through distillation purification equipment, which reduces environmental pollution and improves resource utilization.

[0003] NMP is an important auxiliary material in the production of lithium-ion battery electrodes. It is expensive. When treating wastewater containing NMP, NMP recovery devices are usually used for recycling. Existing NMP recovery devices usually use filtration and distillation methods to convert NMP in wastewater into gas for recycling.

[0004] Existing recycling devices require azeotropic distillation during distillation, which is not only energy-intensive but also generates residual pollution and VOC emissions when using azeotropic agents, damaging the environment. To address these issues, a NMP waste liquid recycling, distillation, and purification device is proposed. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides an NMP waste liquid recovery, distillation and purification device, which aims to improve the problems of high cost and high pollution in the existing technology of distillation separation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A distillation and purification device for NMP waste liquid recovery includes a distillation buffer tank, a distillation column feed pump, a permeate condenser, a permeate buffer tank, and a permeate pump. A discharge pipe is fixedly connected to the outside of the distillation buffer tank. The end of the discharge pipe away from the distillation buffer tank is fixedly connected to the input end of the distillation column feed pump. The output end of the distillation column feed pump is fixedly connected to the outside of the distillation column. The permeate condenser is connected to the distillation column and the permeate buffer tank. The permeate buffer tank is connected to the permeate pump. A cooling component is provided at the outlet end of the permeate buffer tank.

[0008] As a further description of the above technical solution:

[0009] The cooling component includes a tail-cooling tank, which is located at the outlet end of the permeate buffer tank. A tail-cooler is fixedly connected to the top of the tail-cooling tank, and the tail-cooler is connected to the tail-cooling tank. A tail-cooling liquid pump is fixedly connected to the outside of the tail-cooling tank through a pipe.

[0010] As a further description of the above technical solution:

[0011] A nitrogen pipeline is fixedly connected to the top of the distillation buffer tank, and the nitrogen pipeline is connected to the distillation buffer tank.

[0012] As a further description of the above technical solution:

[0013] A vacuum tube is fixedly connected to the outside of the permeate condenser, and a vacuum machine is fixedly connected to the other end of the vacuum tube.

[0014] As a further description of the above technical solution:

[0015] The outside of the permeate condenser is fixedly connected to a low-temperature water inlet pipe and a low-temperature water outlet pipe.

[0016] As a further description of the above technical solution:

[0017] A second vacuum tube is fixedly connected to the outside of the permeate buffer tank, and the second vacuum tube is connected to the first vacuum tube.

[0018] As a further description of the above technical solution:

[0019] Solenoid valves are installed in the middle of the discharge pipe, vacuum tube one, and vacuum tube two.

[0020] This utility model has the following beneficial effects:

[0021] 1. In this utility model, a forced circulation reboiler is adopted, which drives the material to circulate at high speed through a pump, thereby improving the heat transfer coefficient, reducing heat source consumption, and eliminating the need for azeotropic agents, thus reducing energy consumption and saving costs. It does not generate secondary pollution. The high-purity NMP solution after dehydration is treated by a distillation column, which reduces the heat load on the reboiler and further reduces the system energy consumption.

[0022] 2. In this utility model, by setting up a tail cooling tank and a tail cooler, the high-temperature waste liquid generated during the distillation process is cooled down, avoiding direct discharge of high-temperature waste liquid that damages the environment and corrodes equipment. At the same time, the cooled waste liquid is transported to a water washing tower by a tail cooling liquid pump for further treatment, thus achieving environmentally friendly discharge. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an NMP waste liquid recovery, distillation and purification device proposed in this utility model;

[0024] Figure 2 This is a schematic diagram of the process for an NMP waste liquid recovery, distillation and purification device proposed in this utility model.

[0025] Legend:

[0026] 1. Distillation buffer tank; 2. Distillation column feed pump; 3. Permeate condenser; 4. Permeate buffer tank; 5. Permeate pump; 6. Tail cooler tank; 7. Tail cooler pump; 8. Tail cooler; 9. Nitrogen pipeline; 10. Discharge pipe; 11. Vacuum tube one; 12. Vacuum tube two; 13. Solenoid valve; 14. Cryogenic return water pipe; 15. Cryogenic inlet water pipe. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] Reference Figure 1 and Figure 2This utility model provides an embodiment of an NMP waste liquid recovery and distillation purification device, comprising a distillation buffer tank 1, a distillation column feed pump 2, a permeate condenser 3, a permeate buffer tank 4, and a permeate pump 5. The distillation buffer tank 1 is the front-end buffer unit of the entire distillation system, used to receive wet NMP material from the upstream section after being treated by a molecular sieve membrane dehydration device, stabilize the flow rate when the material is delivered to the distillation column, and reduce liquid level fluctuations during feeding. A liquid level sensor is also installed inside the distillation buffer tank 1 to detect the liquid level height. A discharge pipe 10 is fixedly connected to the outside of the distillation buffer tank 1. The end of the discharge pipe 10 away from the distillation buffer tank 1 is fixedly connected to the input end of the distillation column feed pump 2. The distillation buffer tank 1 and the distillation column feed pump 2 are connected through the discharge pipe 10. The raw material inside the distillation buffer tank 1 is output by the distillation column feed pump 2. The output end of the distillation column feed pump 2 is fixedly connected to the outside of the distillation column. The distillation column transports raw materials for processing. A permeate condenser 3 is connected to the distillation column. Inside the distillation column, NMP raw materials form a mixture of NMP and water vapor. This mixture flows to the permeate condenser 3 for cooling and exhaust. The permeate condenser 3 is connected to a permeate buffer tank 4. The NMP condensed in the permeate condenser 3 flows to the permeate buffer tank 4 for temporary storage. The permeate buffer tank 4 is connected to a permeate pump 5, located at the outlet of the permeate buffer tank 4. This pump extracts the liquid from the permeate buffer tank 4 and transports it to the finished product storage tank. Simultaneously, the permeate pump 5 also returns the reflux liquid from the permeate buffer tank 4 to the top of the distillation column, maintaining the reflux ratio required for rectification and improving separation accuracy. A cooling component is installed at the outlet of the permeate buffer tank 4 to cool the high-temperature waste liquid discharged from the permeate buffer tank 4.

[0029] Reference Figure 2 The cooling assembly includes a tail-cooling tank 6, which is located at the outlet of the permeate buffer tank 4. The tail-cooling tank 6 is positioned below the drain port of the permeate buffer tank 4 and can receive and store high-temperature waste liquid. A tail-cooler 8 is fixedly connected to the top of the tail-cooling tank 6 and is connected to the tail-cooling tank 6. The tail-cooler 8 is installed above the tail-cooling tank 6 and is used to cool the high-temperature waste liquid inside the tail-cooling tank 6. The cooled waste liquid can then be discharged into the water washing tower for subsequent processing. A tail-cooling liquid pump 7 is fixedly connected to the outside of the tail-cooling tank 6 through a pipeline. The input end of the tail-cooling liquid pump 7 is connected to the outlet of the tail-cooling tank 6 and transports the cooled waste liquid to the water washing tower through the pipeline, realizing the compliant disposal of waste liquid and avoiding direct discharge of waste liquid that would affect the environment.

[0030] Reference Figure 1 and Figure 2A nitrogen pipeline 9 is fixedly connected to the top of the distillation buffer tank 1. The nitrogen pipeline 9 is connected to the main nitrogen pipeline in the plant and is also connected to the distillation buffer tank 1. Nitrogen is supplied to the distillation buffer tank 1 through the nitrogen pipeline 9 to ensure the stability of the NMP material and facilitate subsequent processing. A vacuum tube 11 is fixedly connected to the outside of the permeate condenser 3. A vacuum machine is fixedly connected to the other end of the vacuum tube 11. The vacuum machine creates a vacuum environment inside the permeate condenser 3 through the vacuum tube 11. A low-temperature water inlet pipe 15 and a low-temperature water outlet pipe 14 are fixedly connected to the outside of the permeate condenser 3. The low-temperature water inlet pipe 15 and the low-temperature water outlet pipe 14 are connected to the main water pipeline in the plant area for cooling. The low temperature of the permeate condenser 3 creates a cold water circulation, allowing the permeate condenser 3 to operate continuously. A vacuum tube 2 12 is fixedly connected to the outside of the permeate buffer tank 4. Vacuum tube 2 12 is connected to vacuum tube 1 11. The connection between vacuum tube 2 12 and vacuum tube 1 11 in the permeate buffer tank 4 can create a negative pressure environment using a vacuum machine. Solenoid valves 13 are installed in the middle of the discharge pipe 10, vacuum tube 1 11, and vacuum tube 2 12. Solenoid valves 13 are installed at both ends of each pipe. The solenoid valves 13 can automatically open or close the pipes, which can regulate the flow and pressure of the pipes, improve the degree of automation, ensure the safety of the pipeline, and facilitate maintenance in case of future pipeline damage.

[0031] Working principle: First, the wet NMP material, after being dehydrated by the molecular sieve membrane, is transported through a pipeline to the distillation buffer tank 1. Then, the NMP material inside the distillation buffer tank 1 is extracted by the distillation column feed pump 2 through the outlet pipe 10 and transported to the distillation column. After being heated in a vacuum environment in the distillation column, the mixed vapor of NMP and water is transported to the permeate condenser 3. The mixed vapor of NMP and water is condensed into a liquid state in the permeate condenser 3. Then, the liquid raw material is transported to the permeate buffer tank 4. Gas-liquid separation is carried out in the permeate buffer tank 4. The gas is discharged to the vacuum machine through the vacuum pipe 12 at the top. The qualified liquid is transported to the finished product storage tank. The unqualified liquid is transported back to the distillation column for processing by the permeate pump 5 to control the quality of the finished product. Each link is equipped with a solenoid valve 13, which can accurately control the flow rate and the opening and closing of the pipeline to ensure the accuracy of processing.

[0032] Secondly, the waste liquid in the permeate buffer tank 4 is discharged to the tail cooler tank 6, and the tail cooler 8 connected above the tail cooler tank 6 is used to cool the waste liquid. Then, the tail cooler pump 7 is used to transport the cooled waste liquid in the tail cooler tank 6 to the water washing tower through the pipeline for waste liquid cleaning.

[0033] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A distillation and purification apparatus for NMP waste liquid recovery, comprising a distillation buffer tank (1), a distillation column feed pump (2), a permeate condenser (3), a permeate buffer tank (4), and a permeate pump (5), characterized in that: The outside of the distillation buffer tank (1) is fixedly connected to a discharge pipe (10). The end of the discharge pipe (10) away from the distillation buffer tank (1) is fixedly connected to the input end of the distillation column feed pump (2). The output end of the distillation column feed pump (2) is fixedly connected to the outside of the distillation column. The permeate condenser (3) is connected to the distillation column. The permeate condenser (3) is connected to the permeate buffer tank (4). The permeate buffer tank (4) is connected to the permeate pump (5). A cooling component is provided at the water outlet of the permeate buffer tank (4).

2. The NMP waste liquid recovery rectification and purification device according to claim 1, characterized in that: The cooling assembly includes a tail-cooling tank (6), which is located at the outlet end of the permeate buffer tank (4). A tail-cooler (8) is fixedly connected to the top of the tail-cooling tank (6), and the tail-cooler (8) is connected to the tail-cooling tank (6). A tail-cooling liquid pump (7) is fixedly connected to the outside of the tail-cooling tank (6) through a pipe.

3. The NMP waste liquid recovery rectification and purification device according to claim 1, characterized in that: A nitrogen pipeline (9) is fixedly connected to the top of the distillation buffer tank (1), and the nitrogen pipeline (9) is connected to the distillation buffer tank (1).

4. The NMP waste liquid recovery rectification and purification device according to claim 1, characterized in that: The outside of the permeate condenser (3) is fixedly connected to a vacuum tube (11), and the other end of the vacuum tube (11) is fixedly connected to a vacuum machine.

5. The NMP waste liquid recovery rectification and purification device according to claim 4, characterized in that: The permeate condenser (3) is fixedly connected to a low-temperature water inlet pipe (15) and a low-temperature water outlet pipe (14).

6. The NMP waste liquid recovery, distillation and purification apparatus according to claim 4, characterized in that: The outside of the permeate buffer tank (4) is fixedly connected to a vacuum tube two (12), which is connected to the vacuum tube one (11).

7. The NMP waste liquid recovery rectification and purification device according to claim 6, characterized in that: Solenoid valves (13) are provided in the middle of the discharge pipe (10), the first vacuum pipe (11) and the second vacuum pipe (12).

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