NMP recovery system

Abstract

The utility model discloses an NMP (N-Methyl Pyrrolidone) recovery system, which relates to the field of material recovery, and comprises a recycling module used for carrying out heat exchange on a first part of gas and waste gas, completing recovery after the first part of gas is heated, separating out NMP after the waste gas is cooled, forming NMP condensate, and carrying out heat exchange on the additionally formed first part of gas and the waste gas, compared with the prior art, the system has the beneficial effects that purification, conversion and recycling of NMP are completed through the recycling module, the waste gas treatment module and the blast cooling module, the cost of raw materials is reduced, cost reduction and efficiency improvement of lithium battery production enterprises are realized, and waste gas is treated; meanwhile, the emergency working module is arranged, when the waste gas treatment module cannot treat gas with the high NMP content in time, NMP is absorbed, and the situation that the NMP content in exhausted waste gas is too high, the surrounding environment is polluted, and the human health of nearby residents is damaged is avoided.

Description

Technical Field

[0001] This utility relates to the field of material recycling, specifically an NMP recycling system. Background Technology

[0002] NMP (N-methylpyrrolidone) is a crucial auxiliary material in the production of lithium-ion battery cathode materials and is a commonly used solvent during the cathode material formulation stage. According to the lithium-ion battery manufacturing process, during the coating and baking stage of the cathode material production, the cathode solvent NMP completely evaporates at high temperatures under the action of circulating hot air.

[0003] The direct emission of NMP-containing exhaust gas into the atmosphere severely pollutes the surrounding environment and harms the health of nearby residents, requiring improvement. Summary of the Invention

[0004] Practical content

[0005] The purpose of this invention is to provide an NMP recycling system to solve the problems mentioned in the background section.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] An NMP recycling system, comprising:

[0008] The recycling module is used to exchange heat between the first part of the gas and the waste gas. After the first part of the gas is heated, it is recovered. After the waste gas is cooled, NMP is released and NMP condensate is formed. The first part of the gas is then exchanged with the waste gas again, and the resulting second part of the gas is output to the waste gas treatment module. The first part of the gas is the tail gas after condensation and recovery. The second part of the gas is also the tail gas after condensation and recovery, wherein the NMP content in the second part of the gas is lower than that in the first part of the gas.

[0009] The exhaust gas treatment module is used to absorb NMP from the third gas (which includes the third and fourth gas sections) to obtain treated exhaust gas, which is then discharged. The fourth gas section absorbs and releases NMP, which is then output to the blower cooling module. The NMP content in the third gas section is lower than that in the fourth gas section.

[0010] The blower cooling module is used to cool the fourth part of the gas after NMP absorption and desorption to form the first part of the gas, which is then output to the recycling module.

[0011] The emergency working module is used to start when the exhaust gas treatment module stops in an emergency. It adsorbs NMP in the second part of the gas through activated carbon and then discharges the second part of the gas after adsorbing NMP into the atmosphere.

[0012] The recycling module is connected to the exhaust gas treatment module, which in turn is connected to the blower cooling module and the emergency operation module. The blower cooling module is then connected to the recycling module.

[0013] As a further improvement of this utility model: the recycling module includes a coating machine, the first end of which is connected to the first end of a heat exchanger, the second end of which is connected to the first end of a blower via a chilled water coil and a first chilled water coil, the second end of which is connected to the third end of the heat exchanger, the third end of which is connected to a waste gas treatment module and a blower cooling module, and the fourth end of which is connected to the second end of the coating machine via a return air blower and a filter.

[0014] As a further improvement of this utility model: the exhaust gas treatment module includes a first VOC rotor, the first end of which is connected to a recycling module, the second end of which is connected to the first end of a second VOC rotor, the third and fourth ends of which are connected to a first steam coil, the fifth end of which is connected to the fifth end of the second VOC rotor, a blower cooling module, the second end of which is sequentially connected to a first electric air valve and a first exhaust blower, and the third and fourth ends of which are connected to a second steam coil.

[0015] As a further improvement of this utility model: the blower cooling module includes a circulating blower, the first end of which is connected to the recycling module, and the second end of which is connected to the exhaust gas treatment module through a second chilled water coil.

[0016] As a further improvement of this utility model: the emergency working module includes a second electric air valve, the first end of which is connected to the waste gas treatment module, and the second end of which is connected in sequence to the activated carbon adsorption box and the second exhaust blower.

[0017] As a further improvement in this practical application, the NMP content in the first part of the gas is 90-95%, and the NMP content in the second part of the gas is less than 90%.

[0018] As a further improvement in this practical application: the NMP content in the third gas is 5-10%, and the NMP content in the fourth gas is 10-90%.

[0019] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention completes the purification, conversion, and reuse of NMP through a recycling module, a waste gas treatment module, and a blower cooling module, reducing raw material costs and enabling lithium battery manufacturers to reduce costs and increase efficiency, while also treating waste gas; at the same time, an emergency working module is set up to absorb NMP when the waste gas treatment module cannot handle the gas with high NMP content in time, thus avoiding excessive NMP content in the discharged waste gas from polluting the surrounding environment and harming the health of nearby residents. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an NMP recycling system.

[0021] In the diagram: 1-Coating machine, 2-Heat exchanger, 3-Chilling water coil, 4-First chilled water coil, 5-Air supply blower, 6-Return air blower, 7-Filter, 8-First VOC rotor, 9-Second VOC rotor, 10-First electric air valve, 11-First exhaust blower, 12-First steam coil, 13-Second steam coil, 14-Second chilled water coil, 15-Circulating blower, 16-Second electric air valve, 17-Activated carbon adsorption box, 18-Second exhaust blower. Detailed Implementation

[0022] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0023] Please see Figure 1 An NMP recycling system, comprising:

[0024] The recycling module is used to exchange heat between the first part of the gas and the waste gas. After the first part of the gas is heated, it is recovered. After the waste gas is cooled, NMP is released and NMP condensate is formed. The first part of the gas is then exchanged with the waste gas again, and the resulting second part of the gas is output to the waste gas treatment module. The first part of the gas is the tail gas after condensation and recovery. The second part of the gas is also the tail gas after condensation and recovery, wherein the NMP content in the second part of the gas is lower than that in the first part of the gas.

[0025] The exhaust gas treatment module is used to absorb NMP from the third gas (which includes the third and fourth gas sections) to obtain treated exhaust gas, which is then discharged. The fourth gas section absorbs and releases NMP, which is then output to the blower cooling module. The NMP content in the third gas section is lower than that in the fourth gas section.

[0026] The blower cooling module is used to cool the fourth part of the gas after NMP absorption and desorption to form the first part of the gas, which is then output to the recycling module.

[0027] The emergency working module is used to start when the exhaust gas treatment module stops in an emergency. It adsorbs NMP in the second part of the gas through activated carbon and then discharges the second part of the gas after adsorbing NMP into the atmosphere.

[0028] The recycling module is connected to the exhaust gas treatment module, which in turn is connected to the blower cooling module and the emergency operation module. The blower cooling module is then connected to the recycling module.

[0029] In this embodiment, please refer to Figure 1 The recycling module includes a coating machine 1. The first end of the coating machine 1 is connected to the first end of the heat exchanger 2. The second end of the heat exchanger 2 is connected to the first end of the air supply blower 5 in sequence through a cold water coil 3 and a first chilled water coil 4. The second end of the air supply blower 5 is connected to the third end of the heat exchanger 2. The third end of the air supply blower 5 is connected to the exhaust gas treatment module and the blower cooling module. The fourth end of the heat exchanger 2 is connected to the second end of the coating machine 1 in sequence through a return air blower 6 and a filter 7.

[0030] The high-temperature exhaust gas emitted from the coating machine 1 is sent to the heat exchanger 2 by the exhaust fan of the coating machine 1, where it exchanges heat with the tail gas (first part gas) after condensation and recovery. After the first part gas is heated, it returns to the drying oven of the coating machine 1 for use. After the exhaust gas is cooled, it enters the cold water coil 3 and the first chilled water coil 4, so that the NMP in the exhaust gas reaches a supersaturated state and condenses and precipitates out, forming NMP condensate. The fine NMP droplets are captured by the demister and also settle into the guide channel and discharged. The tail gas after condensation and recovery has a 90%-95% NMP content (first part gas). It returns to the heat exchanger 2 of the device by the air blower 5 to exchange heat with the exhaust gas of the coating machine 1 and is heated. Then it returns to the drying oven of the coating machine 1 by the return air blower 6 through the filter 7 for recycling.

[0031] In this embodiment, please refer to Figure 1 The exhaust gas treatment module includes a first VOC rotor 8, the first end of which is connected to a recycling module, the second end of which is connected to the first end of a second VOC rotor 9, the third and fourth ends of which are connected to a first steam coil 12, the fifth end of which is connected to the fifth end of the second VOC rotor 9, and a blower cooling module. The second end of the second VOC rotor 9 is sequentially connected to a first electric air valve 10 and a first exhaust blower 11, and the third and fourth ends of the second VOC rotor 9 are connected to a second steam coil 13.

[0032] The condensed exhaust gas from the second part of the gas contains 5%-10% NMP (the third part of the gas). This NMP content enters the first VOC rotor 8 and the second VOC rotor 9. The gas first passes through the adsorption zones of the first and second VOC rotors 8 and 9, where the adsorbents absorb the NMP. After treatment, the exhaust gas from the third part meets the standards and is discharged into the atmosphere via the first exhaust blower 11 (with the first electric air valve 10 open and the second electric air valve 16 closed).

[0033] The fourth gas then passes through the cooling zones of the first VOC rotor 8 and the second VOC rotor 9 to cool the high-temperature adsorbent. After passing through the cooling zones, the fourth gas is heated by passing through the first steam coil 12 and the second steam coil 13 before heading to the regeneration zone of the VOC rotor to desorb the saturated or nearly saturated adsorbent. The third gas after passing through the regeneration zone has a high NMP content.

[0034] In this embodiment, please refer to Figure 1 The blower cooling module includes a circulating blower 15. The first end of the circulating blower 15 is connected to the recycling module, and the second end of the circulating blower 15 is connected to the exhaust gas treatment module through the second chilled water coil 14.

[0035] The third part of the gas after absorbing NMP enters the chilled water coil through the circulating blower 15, where it is cooled and condensed again to form the first part of the gas, which is then output to the heat exchanger 2, thus realizing a tail gas treatment cycle.

[0036] In this embodiment, please refer to Figure 1 The emergency working module includes a second electric air valve 16. The first end of the second electric air valve 16 is connected to the waste gas treatment module, and the second end of the second electric air valve 16 is connected in sequence to the activated carbon adsorption box 17 and the second exhaust blower 18.

[0037] In an emergency, the first steam coil 12 and the second steam coil 13 stop heating, the first electric air valve 10 closes, the second electric air valve 16 opens, the first exhaust blower 11 stops working, and the second exhaust blower 18 starts operating. The second portion of the gas enters the activated carbon adsorption box 17, where NMP molecules are captured by the pores on the surface of the activated carbon, thus purifying the waste gas. After treatment by activated carbon adsorption, the NMP concentration in the waste gas is significantly reduced, meeting environmental emission standards, and can be safely discharged into the atmosphere.

[0038] In this embodiment, please refer to Figure 1 The NMP content in the first part of the gas is 90-95%, while the NMP content in the second part of the gas is less than 90%.

[0039] In this embodiment, please refer to Figure 1 The NMP content in the third gas is 5-10%, and the NMP content in the fourth gas is 10-90%.

[0040] The working principle of this utility model is as follows: The recycling module exchanges heat between the first part of the gas and the waste gas. After the first part of the gas is heated, it is recovered. After the waste gas is cooled, NMP is released, forming NMP condensate. The first part of the gas then exchanges heat with the waste gas again, and the resulting second part of the gas is output to the waste gas treatment module. The first part of the gas is the tail gas after condensation and recovery. The second part of the gas is also the tail gas after condensation and recovery, but the NMP content in the second part of the gas is lower than that in the first part of the gas. The waste gas treatment module absorbs the NMP in the third part of the gas (including the third and fourth parts of the gas) to obtain treated tail gas, which is then discharged. The fourth part of the gas absorbs and releases NMP and is output to the blower cooling module. The NMP content in the third part of the gas is lower than that in the fourth part of the gas. The blower cooling module cools the fourth part of the gas after NMP absorption and release to form the first part of the gas, which is then output to the recycling module. The emergency working module is activated when the waste gas treatment module stops in an emergency. It adsorbs NMP in the second part of the gas through activated carbon and then discharges the NMP-adsorbed second part of the gas into the atmosphere.

[0041] It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered in all respects as exemplary and not restrictive.

[0042] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An NMP recovery system, characterized in that, The NMP recycling system includes: The recycling module is used to exchange heat between the first part of the gas and the waste gas. After the first part of the gas is heated, it is recovered. After the waste gas is cooled, NMP is released and NMP condensate is formed. The first part of the gas is then exchanged with the waste gas again, and the resulting second part of the gas is output to the waste gas treatment module. The first part of the gas is the tail gas after condensation and recovery. The second part of the gas is also the tail gas after condensation and recovery, wherein the NMP content in the second part of the gas is lower than that in the first part of the gas. The exhaust gas treatment module is used to absorb NMP from the third gas (which includes the third and fourth gas sections) to obtain treated exhaust gas, which is then discharged. The fourth gas section absorbs and releases NMP, which is then output to the blower cooling module. The NMP content in the third gas section is lower than that in the fourth gas section. The blower cooling module is used to cool the fourth part of the gas after NMP absorption and desorption to form the first part of the gas, which is then output to the recycling module. The emergency working module is used to start when the exhaust gas treatment module stops in an emergency. It adsorbs NMP in the second part of the gas through activated carbon and then discharges the second part of the gas after adsorbing NMP into the atmosphere. The recycling module is connected to the exhaust gas treatment module, which in turn is connected to the blower cooling module and the emergency operation module. The blower cooling module is then connected to the recycling module.

2. The NMP recovery system according to claim 1, characterized in that, The recycling module includes a coating machine. The first end of the coating machine is connected to the first end of a heat exchanger. The second end of the heat exchanger is connected to the first end of a blower via a chilled water coil and a first chilled water coil. The second end of the blower is connected to the third end of the heat exchanger. The third end of the blower is connected to a waste gas treatment module and a blower cooling module. The fourth end of the heat exchanger is connected to the second end of the coating machine via a return air blower and a filter.

3. The NMP recovery system according to claim 1, characterized in that, The exhaust gas treatment module includes a first VOC rotor, a first end of which is connected to a recycling module, a second end of which is connected to the first end of a second VOC rotor, a third and fourth end of which are connected to a first steam coil, a fifth end of which is connected to the fifth end of the second VOC rotor, a blower cooling module, a second end of which is sequentially connected to a first electric air valve and a first exhaust blower, and a third and fourth end of which are connected to a second steam coil.

4. The NMP recovery system according to claim 1, characterized in that, The blower cooling module includes a circulating blower. The first end of the circulating blower is connected to the recycling module, and the second end of the circulating blower is connected to the exhaust gas treatment module through a second chilled water coil.

5. The NMP recovery system according to claim 1, characterized in that, The emergency working module includes a second electric air valve. The first end of the second electric air valve is connected to the waste gas treatment module, and the second end of the second electric air valve is connected in sequence to the activated carbon adsorption box and the second exhaust blower.

6. The NMP recovery system according to any one of claims 1 to 5, characterized in that, The NMP content in the first part of the gas is 90-95%, while the NMP content in the second part of the gas is less than 90%.

7. The NMP recovery system according to any one of claims 1 to 5, characterized in that, The NMP content in the third gas is 5-10%, and the NMP content in the fourth gas is 10-90%.

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