A dual-stage NMP exhaust gas condensation and adsorption recovery device

Abstract

This utility model discloses a two-stage recovery device for NMP waste gas through condensation and adsorption, belonging to the field of NMP waste gas treatment. The device includes a heat exchanger, a condenser, and an adsorption unit. The inlet end of the heat exchanger on the hot side is connected to an air inlet pipe, and the outlet end is connected to the condenser. The condenser has multiple condensation sections, and heat exchange pipes are installed inside each condensation section. The outlet end of the condenser is connected to an exhaust pipe. The exhaust pipe is connected to a first branch gas pipe and a second branch gas pipe. The first branch gas pipe is connected to the inlet end of the heat exchanger on the cold side, and the outlet end of the heat exchanger on the cold side is connected to a return air pipe. The second branch gas pipe is connected to the inlet end of the adsorption unit, and the outlet end of the adsorption unit is connected to an vent pipe. This utility model employs a two-stage "condensation + adsorption" recovery method, which can efficiently recover and treat N-methylpyrrolidone (NMP) waste gas with a concentration range of 200-2000 mg / m³, and has low operating costs.

Description

Technical Field

[0001] This utility model relates to the field of NMP waste gas treatment, specifically to a two-stage recovery device for NMP waste gas condensation and adsorption. Background Technology

[0002] With the rapid development of new energy and new materials industries, N-methylpyrrolidone (NMP), as an important organic solvent, is widely used in lithium battery manufacturing, semiconductor production, and other fields. However, NMP emissions not only pollute the environment but also waste valuable resources. Therefore, developing efficient NMP emissions recovery devices is of great significance, as it can achieve environmental protection and emission reduction, recover resources, and reduce production costs.

[0003] Currently, the following treatment process is used to recover low-to-medium concentration NMP waste gas (500-5000 mg / m³): waste gas → pretreatment → adsorption device (activated carbon / resin adsorption) → emission to meet standards → after adsorption saturation → hot nitrogen desorption → condensation recovery → NMP distillation purification. This requires the use of specialized adsorption materials and desorption needs to be carried out at 120-150℃, resulting in high operating costs, and the recovery rate of NMP waste gas needs to be further improved. Utility Model Content

[0004] Based on the above-mentioned technical problems, this utility model proposes a two-stage recovery device for NMP waste gas condensation and adsorption.

[0005] The technical solution adopted by this utility model is: A two-stage NMP exhaust gas condensation and adsorption recovery device includes a heat exchanger, a condenser, and an adsorption unit; The inlet end of the heat exchanger on the hot side is connected to the air inlet duct, and an air inlet fan is installed on the air inlet duct. The outlet end of the heat side is connected to the condenser. The condenser includes a condensing shell, inside which a first condensing section and a second condensing section are arranged. Inside the first condensing section, a first heat exchange pipe is arranged, and inside the second condensing section, a second heat exchange pipe is arranged. The end of the condensing shell where the first heat exchange pipe is arranged is connected to the outlet end of the hot side, and the end of the condensing shell where the second heat exchange pipe is arranged is connected to the exhaust pipe. The exhaust pipe is connected to the first branch gas pipe and the second branch gas pipe. The first branch gas pipe is connected to the inlet end of the cold side of the heat exchanger, and the outlet end of the cold side of the heat exchanger is connected to the return air pipe. The second branch gas pipeline connects to the inlet end of the adsorption unit, and the outlet end of the adsorption unit connects to the venting pipeline.

[0006] Preferably, the air inlet duct is connected to the NMP exhaust gas outlet duct; both the first heat exchange duct and the second heat exchange duct are arranged in a serpentine pattern, and cooling medium is introduced into both the first heat exchange duct and the second heat exchange duct.

[0007] Preferably, the first and second heat exchange pipes inside the condenser shell are filled with cooling medium, and the condenser shell is connected to the waste liquid collection tank through the liquid outlet pipe.

[0008] Preferably, the device further includes a filter disposed at the end of the condenser housing or on the exhaust duct.

[0009] Preferably, the adsorption unit includes a primary adsorption unit and a secondary adsorption unit. The second branch gas pipeline is connected to the inlet end of the primary adsorption unit, the outlet end of the primary adsorption unit is connected to the inlet end of the secondary adsorption unit through a gas connection pipeline, an exhaust gas fan is installed on the gas connection pipeline, and the outlet end of the secondary adsorption unit is connected to an exhaust pipeline.

[0010] Preferably, activated carbon or molecular sieves are filled in the primary adsorption unit and the secondary adsorption unit.

[0011] The beneficial technical effects of this utility model are as follows: This invention employs a two-stage recovery process of "condensation + adsorption," which can efficiently recover and treat N-methylpyrrolidone (NMP) waste gas with a concentration range of 200-2000 mg / m³. Moreover, it has low operating costs, achieving both environmental protection and emission reduction, while also recovering NMP and preventing resource waste.

[0012] Specifically, this utility model has the following significant advantages: (1) High recovery rate, reducing raw material loss; Condensation stage: Through two-stage condensation, most of the NMP in the waste gas is liquefied and recovered, with a recovery rate of over 85%, significantly improving the recovery efficiency.

[0013] Adsorption stage: Activated carbon or molecular sieves are used for adsorption to deeply adsorb the remaining low-concentration NMP waste gas, and the total recovery rate can be increased to over 99%, significantly reducing raw material costs.

[0014] (2) Energy conservation and environmental protection, reducing emissions; Waste heat utilization of condensation: Gas-to-gas heat exchange is used in the heat exchanger to heat the condensed cold air, optimizing energy consumption and saving 20% ​​to 30% energy compared to the traditional single condensation method.

[0015] Emissions meet standards: The NMP concentration in the treated exhaust gas can be reduced to 1~2 mg / m³, which is far below the emission requirements of GB 31571-2015 "Integrated Emission Standard for Air Pollutants", thus avoiding environmental pollution.

[0016] (3) Highly adaptable; Adjustable condensation temperature: The condensation temperature of the first and second condensation sections can be flexibly adjusted according to the exhaust gas concentration and operating conditions to adapt to different NMP volatilization scenarios (such as lithium iron phosphate battery, ternary battery coating, etc.).

[0017] The adsorption material uses activated carbon or molecular sieves, which are easy to regenerate or replace and convenient to maintain.

[0018] Closed-loop system: The entire process is handled in a closed loop to avoid exposure of personnel to NMP volatile substances and reduce occupational health hazards.

[0019] (4) Significant economic benefits; Recycled NMP can be reused: The recycled liquid NMP has high purity (≥95%) and can be purified and reused in production, reducing procurement costs.

[0020] In summary, this utility model achieves efficient recovery and environmentally compliant emissions of NMP waste gas through a two-stage "condensation + adsorption" recovery process, employing staged condensation and multi-stage adsorption. It boasts advantages such as high recovery rate, low energy consumption, and safety and reliability, making it suitable for industries such as lithium batteries, PCBs, and pharmaceutical synthesis. This helps companies reduce costs, increase efficiency, and meet green production requirements. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the structural principle of one embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the structural principle of another embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the structural principle of one embodiment of the condenser in this utility model.

[0022] In the diagram: 1-Heat exchanger, 2-Condenser, 3-Adsorption unit, 4-Inlet air duct, 5-Inlet air fan, 6-First branch gas duct, 7-Second branch gas duct, 8-Return air duct, 9-Return air fan, 10-Exhaust duct, 11-Filter, 12-Exhaust duct; 201-Condensation shell, 202-First condensation section, 203-Second condensation section, 204-First heat exchange pipe, 205-Second heat exchange pipe, 206-Waste liquid collection tank, 207-Liquid outlet pipe; 301 - Primary adsorption unit, 302 - Secondary adsorption unit, 303 - Gas connection pipe, 304 - Exhaust gas fan. Detailed Implementation

[0023] like Figure 1As shown, a two-stage NMP exhaust gas condensation and adsorption recovery device includes a heat exchanger 1, a condenser 2, and an adsorption unit 3. The inlet end of the heat exchanger 1 on the hot side is connected to an air inlet duct 4, and an air inlet fan 5 is installed on the air inlet duct 4. The outlet end of the heat exchanger 1 on the hot side is connected to the condenser 2. The condenser includes a condensation shell 201, inside which are a first condensation section 202 and a second condensation section 203. A first heat exchange pipe 204 is installed inside the first condensation section 202, and a second heat exchange pipe 205 is installed inside the second condensation section 202. The end of the condensation shell 201 where the first heat exchange pipe is located is connected to the outlet end on the hot side, and the end of the condensation shell 201 where the second heat exchange pipe is located is connected to an exhaust pipe 12. The exhaust pipe 12 connects to a first branch gas pipe 6 and a second branch gas pipe 7. The first branch gas pipe 6 is connected to the inlet end of the heat exchanger 1 on the cold side, and the outlet end of the heat exchanger 1 on the cold side is connected to a return air pipe 8, on which a return air fan 9 is installed. The second branch gas pipeline 7 is connected to the inlet end of the adsorption unit 3, and the outlet end of the adsorption unit 3 is connected to the exhaust pipeline 10.

[0024] As a further design feature of this invention, the air inlet pipe 4 is connected to the NMP exhaust gas outlet pipe. Both the first heat exchange pipe 204 and the second heat exchange pipe 205 are arranged in a serpentine pattern. Cooling medium is introduced into both the first heat exchange pipe 204 and the second heat exchange pipe 205. The NMP exhaust gas can be condensed in stages by adjusting the form or flow rate of the cooling medium introduced into the first heat exchange pipe 204 and the second heat exchange pipe 205.

[0025] like Figure 3 As shown, the condenser shell 201 is connected to the waste liquid collection tank 206 via the liquid outlet pipe 207. The NMP in the high-concentration NMP waste gas is condensed, collected, and transported to the waste liquid collection tank 206 for unified treatment.

[0026] Furthermore, the device also includes a filter 11, which is disposed at the end of the condenser housing 201. Alternatively, as... Figure 2 As shown, the filter 11 is disposed in the filter chamber, which is disposed on the exhaust pipe 12.

[0027] The aforementioned adsorption unit 3 includes a primary adsorption unit 301 and a secondary adsorption unit 302. A second branch gas pipeline 7 is connected to the inlet of the primary adsorption unit 301, and the outlet of the primary adsorption unit 301 is connected to the inlet of the secondary adsorption unit 302 via a gas connection pipeline 303. A tail gas fan 304 is installed on the gas connection pipeline 303, and the outlet of the secondary adsorption unit 302 is connected to an exhaust pipeline 10. Activated carbon or molecular sieves are filled in both the primary adsorption unit 301 and the secondary adsorption unit 302. Of course, the activated carbon or molecular sieves can adopt a quick-release modular structure for easy regeneration or replacement.

[0028] The working process of this utility model is roughly as follows: High-temperature, high-concentration exhaust air from the coating workshop passes through the NMP exhaust gas discharge pipe and the intake pipe 4, and is drawn to the heat exchanger 2 by the intake fan 5. In the heat exchanger 2, the hot air heats the condensed cold air, lowering its temperature before it enters the condensation process. In the first condensation section 202 and the second condensation section 203 of the condenser 2, the NMP in the high-concentration NMP exhaust gas is condensed, collected, and transported to the waste liquid collection tank 206 for unified treatment. After multi-stage condensation, the exhaust gas passes through the filter 11, where impurities are intercepted. A portion of the exhaust gas returns to the heat exchanger 1 through the first branch gas pipe. In the heat exchanger 1, it undergoes thorough heat exchange with the high-temperature, high-concentration exhaust air from the coating workshop, and is then drawn back to the workshop by the return air fan 9 for continued use.

[0029] The remaining exhaust gas is drawn by the exhaust gas fan 304, first passing through the primary adsorption unit 301, where the NMP concentration is reduced by 95-99%, and then passing through the secondary adsorption unit, where the concentration is reduced again by 95-99%. Finally, the NMP content in the exhaust pipe can be reduced to 1-2 mg / m³.

[0030] High-concentration NMP waste gas undergoes two-stage condensation and two-stage molecular sieve adsorption in this device, achieving an NMP recovery rate of up to 99.9%. The NMP concentration at the emission outlet is far below industry standards, meeting the emission concentration requirements of domestic and international lithium battery users.

[0031] The technical principles and features of this utility model are explained below: (1) Condensation principle: Utilizing the high miscibility of NMP and water, NMP in the exhaust gas is condensed through water absorption. This process includes primary condensation and secondary condensation to improve condensation efficiency. Cooling water and chilled water can be used as cooling media for primary condensation and secondary condensation, respectively.

[0032] (2) Adsorption principle: Based on condensation, molecular sieve rotors are used to adsorb NMP in the remaining waste gas to further purify the waste gas.

[0033] (3) Two-stage recovery: The first-stage condensation targets NMP in the remaining waste gas, while the second-stage condensation targets residual NMP in the low-temperature waste gas. At the same time, the adsorption process can also recover some NMP, thus achieving two-stage recovery.

[0034] (4) High efficiency and energy saving: The device is designed with a heat exchanger, which can recover the heat energy in the waste gas and use it to preheat the air returned to the coating workshop, etc., so as to achieve efficient use of energy.

[0035] For any parts not mentioned above, existing technologies can be adopted or referenced.

[0036] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A two-stage NMP exhaust gas condensation and adsorption recovery device, characterized in that: Includes heat exchangers, condensers, and adsorption units; The inlet end of the heat exchanger on the hot side is connected to the air inlet duct, and an air inlet fan is installed on the air inlet duct. The outlet end of the heat side is connected to the condenser. The condenser includes a condensing shell, inside which a first condensing section and a second condensing section are arranged. Inside the first condensing section, a first heat exchange pipe is arranged, and inside the second condensing section, a second heat exchange pipe is arranged. The end of the condensing shell where the first heat exchange pipe is arranged is connected to the outlet end of the hot side, and the end of the condensing shell where the second heat exchange pipe is arranged is connected to the exhaust pipe. The exhaust pipe is connected to the first branch gas pipe and the second branch gas pipe. The first branch gas pipe is connected to the inlet end of the cold side of the heat exchanger, and the outlet end of the cold side of the heat exchanger is connected to the return air pipe. The second branch gas pipeline connects to the inlet end of the adsorption unit, and the outlet end of the adsorption unit connects to the venting pipeline.

2. The NMP waste gas condensation adsorption dual-stage recovery device according to claim 1, characterized in that: The air inlet duct is connected to the NMP exhaust gas outlet duct; both the first heat exchange duct and the second heat exchange duct are arranged in a serpentine pattern, and cooling medium is introduced into both the first heat exchange duct and the second heat exchange duct.

3. The NMP waste gas condensation adsorption dual-stage recovery device according to claim 1, characterized in that: Cooling medium is filled in the first and second heat exchange pipes inside the condenser shell, and the condenser shell is connected to the waste liquid collection tank through the liquid outlet pipe.

4. The NMP waste gas condensation adsorption dual-stage recovery device according to claim 1, characterized in that: The device also includes a filter, which is located at the end of the condenser housing or on the exhaust duct.

5. The NMP waste gas condensation adsorption dual-stage recovery device according to claim 1, characterized in that: The adsorption unit includes a primary adsorption unit and a secondary adsorption unit. The second branch gas pipeline is connected to the inlet end of the primary adsorption unit. The outlet end of the primary adsorption unit is connected to the inlet end of the secondary adsorption unit through a gas connection pipeline. An exhaust gas fan is installed on the gas connection pipeline. The outlet end of the secondary adsorption unit is connected to an exhaust pipeline.

6. The NMP waste gas condensation adsorption dual-stage recovery device according to claim 1, characterized in that: Activated carbon or molecular sieves are filled in the primary and secondary adsorption units.

Images