System for purifying n-methyl-2-pyrrolidone, and method therefor

Abstract

The present invention relates to a system for purifying N-methyl-2-pyrrolidone, and a method therefor, and, to an NMP purification system comprising: a first module unit including a booster fan unit for collecting waste NMP gas, and a waste NMP gas adsorption unit for adsorbing the waste NMP gas and converting same into a waste NMP solution; a second module unit which is adjacent to the first module unit, and which includes a DI water supply unit for supplying DI water used for the waste NMP gas adsorption unit; a third module unit which is adjacent to the second module unit, and which includes a first purification unit for purifying, through permeation and evaporation, the waste NMP solution supplied from the first module unit; a fourth module unit which is adjacent to the third module unit, and which includes a second purification unit for purifying, through distillation, the purified NMP solution supplied from the third module unit, and a third purification unit for purifying, through distillation, the NMP solution purified in the second purification unit; and a fifth module unit which is adjacent to the fourth module unit, and which includes a fourth purification unit for purifying, through vaporization, the purified NMP solution supplied from the fourth module unit.

Description

N-methyl-2-pyrrolidone purification system and method thereof

[0001] The present invention relates to an N-methyl-2-pyrrolidone purification system and method thereof, and relates to an N-methyl-2-pyrrolidone purification system and method thereof that is energy efficient, easy to install and manage the system, and capable of stably performing N-methyl-2-pyrrolidone purification.

[0002]

[0003] With the recent popularization of electric vehicles, the secondary battery industry is experiencing rapid growth. Secondary batteries consist of anodes, cathodes, and electrolytes, and are manufactured through a packaging process. The cathode is the active material used in the positive electrode, which undergoes reduction during secondary battery discharge. The anode, on the other hand, is the active material used in the negative electrode, which releases electrons to the conductor through an oxidation reaction during secondary battery discharge.

[0004] A binder is required to manufacture cathode materials. The binder is composed of a combination of PVDF (Polyvinylidene Fluoride) and NMP (N-Methyl-2-Pyrrolidone), and a large amount of NMP is required for the binder for cathode materials. Binders using PVDF and NMP have excellent adhesive strength, facilitate the dispersion of conductive materials, and maintain a stable state even during oxidation / reduction reactions. The pure NMP contained in the binder is mostly volatilized into gas due to heat and pressure during the cathode coating process during the secondary battery manufacturing process. The volatilized NMP can be captured and recycled. NMP regeneration methods can be broadly classified into three types, depending on the method of capturing the used NMP gas, the method of purifying the captured NMP, and the location of the NMP collector and NMP purifier used.

[0005] The classification according to the capture method of the used NMP gas includes the dry capture method and the wet method, and the captured NMP purification method includes the distillation method, the rectification method, the stripping vessel method, and the adsorption method. The classification according to the location of the collector and the purifier includes the on-site method where the collector and the purifier are connected, and the method where the spent NMP liquid, which has been converted into a state by adsorbing pure water on the used NMP gas through capture, is regenerated using an external spent NMP purification system.

[0006] Typically, the secondary battery manufacturing process generates approximately 1,000 tons of waste NMP per 1 GWh of battery capacity. Waste NMP is composed of approximately 72% NMP, 20% moisture, 7% nitride compounds, and approximately 1% polymer and other impurities (particles). Therefore, an economical and reliable method for regenerating waste NMP is needed.

[0007]

[0008] The present invention relates to an NMP purification system and method having high energy efficiency and capable of large-scale regeneration.

[0009] In addition, the present invention relates to an NMP purification system and method thereof that can reduce the installation cost of the NMP purification system and shorten the installation period.

[0010] In addition, the present invention relates to an NMP purification system and method capable of efficiently managing an NMP purification process and preventing safety accidents.

[0011]

[0012] The present invention relates to an NMP purification system comprising: a first module unit including a booster fan unit for capturing waste NMP gas and a waste NMP gas adsorption unit for adsorbing the waste NMP gas and converting it into a waste NMP solution; a second module unit adjacent to the first module unit and including a DI water supply unit for supplying DI water used in the waste NMP gas adsorption unit; a third module unit adjacent to the second module unit and including a first purification unit for purifying the waste NMP solution supplied from the first module unit by pervaporation; a fourth module unit adjacent to the third module unit and including a second purification unit for purifying the purified NMP solution supplied from the third module unit by distillation and a third purification unit for purifying the NMP solution purified in the second purification unit by distillation; and a fifth module unit adjacent to the fourth module unit and including a fourth purification unit for purifying the purified NMP solution supplied from the fourth module unit by vaporization.

[0013] Here, a first module connecting portion for connecting neighboring modules between the first to fifth module portions is further included, wherein the first module connecting portion can be connected in a bolt form by aligning a module fixing portion provided on a frame on the outer surface of each of the first to fifth module portions with a module fixing plate and adding a fixing pad.

[0014] In addition, each of the first to fifth module sections includes a fixing section for fixing a device for NMP purification located inside each module; and a ground connection section for installing each module on the ground at the bottom of each module section; and the ground connection section can be installed on the ground and connected to a second module connection section for installing and fixing each module section on the ground.

[0015] Additionally, the third module unit may include a first inspection unit that inspects the state of the NMP solution purified in the first purification unit using a spectroscopic method.

[0016] Additionally, the first inspection unit inspects the moisture content contained in the purified NMP, and the first purification unit can purify the purified NMP again if the moisture content contained in the purified NMP exceeds a preset moisture content.

[0017] Additionally, the fifth module unit may include a second inspection unit that collects a sample of the NMP solution purified in the fourth purification unit and inspects it using a component analysis method to analyze the state of the NMP solution purified in the fourth purification unit.

[0018] In addition, the second inspection unit may include a sample NMP storage unit for storing a predetermined amount of sample NMP; a sample NMP input unit for inputting a predetermined amount of sample NMP supplied from the outside into the sample NMP storage unit; a sample NMP transfer unit for transferring the sample NMP from the sample NMP storage unit to a sample NMP container; a sample NMP inspection unit for analyzing the components of the sample NMP stored in the sample NMP container; and a sample NMP container storage unit for storing the sample NMP container.

[0019] Additionally, the NMP purified in at least one of the second to fourth purification units can be purified again using at least one of the moisture content contained in the NMP purified in the fourth purification unit or the purity of the purified NMP.

[0020] In addition, the second and third purification units may use a distillation column to purify the purified NMP solution supplied from the third module unit, and the vaporized water may be positioned at the top of the distillation column used in the second purification unit and the purified NMP may be positioned at the bottom, and the vaporized NMP may be positioned at the top of the distillation column used in the third purification unit and the impurities may be positioned at the bottom.

[0021] Additionally, the fourth purification unit can cause moisture to evaporate as the purified NMP solution supplied from the fourth module unit passes through a passage of a predetermined length.

[0022]

[0023] The present invention applies an automated approach to the NMP purification process, enabling efficient management through real-time monitoring. This increases productivity and energy efficiency, enabling large-scale NMP regeneration. Furthermore, the present invention allows the NMP purification system to be configured in a modular manner, reducing on-site installation costs and shortening installation times.

[0024]

[0025] Figure 1 is a drawing showing the main configuration of an NMP purification system according to one embodiment of the present invention.

[0026] Figure 2 is a drawing showing the main configuration of each module part constituting the NMP purification system according to one embodiment of the present invention.

[0027] Figure 3 is a drawing showing the configuration of a second inspection unit according to one embodiment of the present invention.

[0028] Figure 4 is a flowchart for explaining the operation of an NMP purification system according to one embodiment of the present invention.

[0029]

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In describing the present invention, detailed descriptions of known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the invention.

[0031]

[0032] Figure 1 is a drawing showing the main configuration of an NMP purification system according to one embodiment of the present invention.

[0033] The NMP purification system of the present invention is composed of first to fifth module parts (100, 110, 120, 130, 140) and a control part (150), and each module part is equipped with a device for NMP purification. Each module part is manufactured in advance and transported to the site where the NMP purification system is to be installed, and at the site, each module part can be connected to install the NMP purification system. For example, the first to fifth module parts (100, 110, 120, 130, 140) are configured to be transportable in a container size, and each module part is manufactured so that each component included in each module part is connected to each other and can operate internally, and at the site where the NMP purification system is to be installed, the connection part between each module part can be connected, such as a piping connection, and installed.

[0034] Each of the first to fifth module sections (100, 110, 120, 130, 140) is composed of at least one block, and each block has an outer surface composed of a plurality of frames and a frame for connecting each block with the other block, wherein the frame may use an H-beam. In addition, each module section includes a fixing section for fixing a device provided for NMP purification inside, and the fixing section connects a frame provided on the outer surface of each module section and a support beam for supporting a device provided inside each module section. In addition, a first module connecting section is provided between each module section for connecting each neighboring module section, and the first module connecting section aligns the module fixing section provided on the frame on the outer surface of each module section with a module fixing plate, adds a fixing pad, and then connects it in a bolt form. This is to minimize damage to other modules when an abnormality occurs in a certain module, such as when support for a certain module is weakened due to vibration or the ground.

[0035] Each module part is installed and fixed on the ground by connecting the ground connection part provided at the bottom of each module part and the second module connection part installed on the ground. The second module connection part includes the ground-embedded part and the connection part, and the ground-embedded part is buried in the ground and firmly fixed, and then the floor-side construction is carried out to allow the floor layer cement to completely cure and the connection part is exposed above the floor layer. Each module part is installed on the ground by aligning the ground connection part provided in each module part and the connection part provided in the second module connection part, adding a fixing pad, and connecting them with a bolt method.

[0036] The control unit (150) controls the entirety of the present invention, including controlling the process for purifying waste NMP into high-purity purified NMP.

[0037]

[0038] FIG. 2 is a drawing showing the main configuration of each module part constituting the NMP purification system according to one embodiment of the present invention.

[0039] Referring to FIG. 2, the detailed configuration of the first to fifth module units (100, 110, 120, 130, 140) of the present invention will be examined. The first module unit (100) is equipped with a booster fan unit (200) and a waste NMP gas adsorption unit (210), the second module unit (110) is equipped with a DI water supply unit (220), and the third module unit (120) is equipped with a first purification unit (230), a first inspection unit (240), and a first purified NMP storage unit (250). In addition, the fourth module unit (130) is equipped with a second purification unit (260) and a third purification unit (270), and the fifth module unit (140) is equipped with a fourth purification unit (280), a second inspection unit (290), and a second purified NMP storage unit (295). In Fig. 2, each module section is illustrated with respect to the main components, and may further include various components in addition to the illustrated components. For example, each module section may be suitably equipped with a storage section for storing waste NMP, a storage section for storing purified NMP, a sensor section for detecting the status of devices within each module, and piping, wiring, pumps, valves, and containers for transporting waste NMP or purified NMP.

[0040] The booster fan unit (200) captures waste NMP gas generated during the cathode material coding and drying stage of the secondary battery production process using a forced exhaust method and transfers it to the waste NMP gas absorption unit (210).

[0041] In the waste NMP gas adsorption unit (210), pure distilled water is adsorbed onto the waste NMP gas, and the waste NMP gas is converted into a waste NMP liquid containing a large amount of pure distilled water. For example, the pure distilled water may be DI water (De-ionized water), and the waste NMP liquid may contain about 20 to 30% DI water. The liquefied waste NMP is transferred to a waste NMP storage unit (not shown). At this time, the waste NMP storage unit (not shown) may include a filter for removing various particles such as metal particles and organic particles contained in the waste NMP liquid, and the waste NMP liquid stored in the waste NMP storage unit (not shown) may have most of the particles filtered out by the filter, and the main composition of the waste NMP may be composed of pure distilled water and NMP. The waste NMP liquid from which the particles have been removed in the waste NMP storage unit (not shown) undergoes a waste NMP purification process in the first to fourth purification units (230, 280).

[0042] The DI water supply unit (220) supplies DI water to the waste NMP gas adsorption unit (210) and can produce and supply DI water.

[0043] The first purification unit (230) separates pure distilled water and NMP from the waste NMP liquid. For example, the first purification unit (230) can use a pervaporation method. The separation membrane used in the pervaporation method is a GET membrane, which is a structure in which PVA of about 0.2 micrometers is grafted onto a porous PAN 100 micrometer support, and a support layer made of polyester nonwoven fabric of about 100 micrometers is supported on the outside. This pervaporation method is a physical regeneration method and has high energy efficiency, so that a certain amount of moisture can be removed before purification in the second to fourth purification units (260, 290), thereby shortening the distillation time and increasing energy efficiency.

[0044] The NMP purified in the first purification unit (230) is stored in the first purified NMP storage unit (250), and the first inspection unit (240) inspects the components contained in the purified NMP stored in the first purified NMP storage unit (250). For example, a portion of the transport pipe for introducing or discharging the purified NMP into the first purified NMP storage unit (250) is configured as a transparent pipe, and infrared or other light is irradiated onto the transparent pipe to inspect the components of the purified NMP, such as the moisture content contained in the purified NMP, in real time. At this time, the first inspection unit (240) may use the FT-NIR (Fourier Transform Near Infrared) method. In addition, a flow sensor is provided in the pipe for transporting purified NMP to the first purified NMP storage unit (250), so that the flow rate of purified NMP transported through the pipe can be measured, and the amount of purified NMP stored in the first purified NMP storage unit (250) can be measured through a level sensor provided in the first purified NMP storage unit (250).

[0045] The second and third purification units (260, 270) further purify the NMP purified in the first purification unit (230) using a distillation method. For example, the second and third purification units (260, 270) may use a distillation column. Looking at the purification process in the second purification unit (260), the NMP purified in the first purification unit (230) is a mixture of water and NMP, so that it can be divided into low-boiling-point components and high-boiling-point components. In the second purification unit (260), the low-boiling-point components are vaporized first, so that the vaporized water is located at the upper part of the second purification unit (260) and the purified NMP is located at the lower part of the second purification unit (260). The vaporized water at the upper part of the second purification unit (260) is cooled and then transferred to an external tank for processing.

[0046] The purified NMP at the bottom of the second purification unit (260) is transferred to the third purification unit (270), and in the third purification unit (270), the low-boiling-point components are vaporized first, so that the vaporized NMP is located at the top of the third purification unit (270) and the impurities are located at the bottom of the third purification unit (270). The purified NMP located at the top of the third purification unit (270) is cooled and then transferred to the fourth purification unit (280), and the impurities located at the bottom of the third purification unit (270) are transferred to a waste tank (not shown) for disposal.

[0047] The purified NMP that has undergone the purification process in the second and third purification units (260, 270) is transferred to the fourth purification unit (280). In the fourth purification unit (280), the purification process is performed using a vaporization method. For example, the purified NMP is passed through a passage of a predetermined length so that moisture is vaporized. The purified NMP that has undergone the purification process in the fourth purification unit (280) is stored in the second purified NMP storage unit (295), and the second inspection unit (290) inspects the components of the purified NMP stored in the second purified NMP storage unit (295).

[0048] Meanwhile, the present invention can collect data generated in all processes for refining gaseous waste NMP into high-purity purified NMP using various sensors. Various data such as temperature, pressure, and flow rate are collected in real time and transmitted to the control unit (150), so that the manager can monitor the purification process in real time. For example, the temperature, pressure, storage amount, purity of the stored liquid, and pH of the first and second purified NMP storage units (250, 295) can be measured in real time, and the flow rate and temperature can be measured in real time using sensors mounted on the pipe. This data can be compared with preset normal state data to check for abnormalities, and if an abnormality is found, the quality of the purified NMP can be managed or safety accidents can be prevented in advance by modifying the conditions of the purification process discussed above or stopping the purification process.

[0049] In addition, the control unit (150) can learn using deep learning using artificial neural networks such as CNN (Convolution Neural Network), DNN (Deep Neural Network), and RNN (Recurrent Neural Network), and can learn various data to set an optimal state, and can detect the presence or absence of an abnormality in each process in advance. In addition, the control unit (150) can suggest optimal process conditions to the manager, and can notify the manager of a process process that requires a change in process conditions in multiple processes to improve the quality of the purified NMP. For example, the control unit (150) can learn data generated in each process and data on the purified NMP, and can derive a correspondence between the data in each process and the purified NMP, and when the quality of the purified NMP does not meet the standard, it can determine which process needs to be modified and suggest a modification of the process conditions in a given process to the manager. To this end, the control unit (150) can learn in advance the correspondence relationship between data generated from the first purification unit (230) and the first purified NMP storage unit (250), and the correspondence relationship between data generated from the second to fourth purification units (260, 270, 280) and the second purified NMP storage unit (295). In addition, the learned data can be updated, and thus can be updated to reflect modifications to process conditions that occur during the purification process. In addition, the control unit (150) can connect to the outside through a communication network to collect / analyze information on new technologies or new process conditions related to waste NMP purification, and provide the relevant information to the manager, and can suggest to the manager to change a predetermined process condition among the waste NMP processes of the present invention based on the collected / analyzed data.

[0050] In addition, when the moisture content contained in the purified NMP stored in the first purified NMP storage unit (250) exceeds a preset moisture content, the purified NMP stored in the first purified NMP storage unit (250) can be transferred to the first purification unit (230) to be purified again. In addition, when the flow rate of the purified NMP through the pipe exceeds a preset amount, the amount of the flow rate can be reduced, and when the amount of the purified NMP stored in the first purified NMP storage unit (250) exceeds a preset amount, the purification in the first purification unit (230) can be stopped or the purified NMP can be controlled not to be discharged from the first purification unit (230) to the first purified NMP storage unit (250).

[0051] In addition, when the moisture content contained in the purified NMP stored in the second purified NMP storage unit (295) exceeds the preset moisture content, the process conditions applied in the purification process in the second to fourth purification units (260, 290) such as temperature control or purification time control may be changed, or the purification process in the second to fourth purification units (260, 290) may be performed again for the purified NMP stored in the second purified NMP storage unit (295) to perform NMP purification. For example, if the moisture content contained in the purified NMP stored in the second purified NMP storage unit (295) is equal to or greater than the first target value, the purified NMP stored in the second purified NMP storage unit (295) is transferred to perform the purification process in the second to fourth purification units (260, 290) again, and if the moisture content contained in the purified NMP stored in the second purified NMP storage unit (295) is less than the first target value but equal to or greater than the second target value, the purification process in the third and fourth purification units (270, 280) is performed again, and if the moisture content contained in the purified NMP stored in the second purified NMP storage unit (295) is less than the second target value but equal to or greater than the third target value, the purification process in the fourth purification unit (280) can be performed again.

[0052] In addition, if the purity of the purified NMP stored in the second purified NMP storage unit (295) is lower than the preset value, the purification process in the second to fourth purification units (260, 290) may be performed again to purify the NMP. For example, if the purity of the purified NMP stored in the second purified NMP storage unit (295) is lower than the first target value, the purified NMP stored in the second purified NMP storage unit (295) is transferred and the purification process in the second to fourth purification units (260, 290) may be performed again, and if the purity of the purified NMP stored in the second purified NMP storage unit (295) exceeds the first target value but is lower than the second target value, the purification process in the third and fourth purification units (270, 280) may be performed again, and if the purity of the purified NMP stored in the second purified NMP storage unit (295) exceeds the second target value but is lower than the third target value, the purification process in the fourth purification unit (280) may be performed again.

[0053] The control unit (150) can control the purification process by using either the moisture content contained in the purified NMP or the purity of the purified NMP, or both.

[0054]

[0055] FIG. 3 is a drawing showing the configuration of a second inspection unit (290) according to one embodiment of the present invention.

[0056] Referring to FIG. 3, the second inspection unit (290) includes a sample NMP input unit (300), a sample NMP storage unit (310), a sample NMP transfer unit (320), a sample NMP inspection unit (330), and a sample NMP container storage unit (340).

[0057] The sample NMP input unit (300) is located between the second purified NMP storage unit (295) and the sample NMP storage unit (310), and inputs a predetermined amount of sample NMP from among the purified NMP stored in the second purified NMP storage unit (295) into the sample NMP storage unit (310). To this end, the sample NMP input unit (300) includes an automatic valve, such as a solenoid valve, and is opened and closed under the control of the control unit (150). For example, the control unit (150) can control the sample NMP input unit (300) to be closed when the level of the sample NMP stored in the sample NMP storage unit (310) is higher than a preset level value, and to be opened when it is lower than the preset level value.

[0058] The sample NMP storage unit (310) stores the sample NMP supplied from the second purified NMP storage unit (295), and the stored sample NMP is transferred to and stored in a sample NMP container.

[0059] The sample NMP transfer unit (320) is located between the sample NMP storage unit (310) and the sample NMP container, and transfers the sample NMP stored in the sample NMP storage unit (310) to the sample NMP container. For example, the sample NMP transfer unit (320) may include a cylinder including a piston and a nozzle, and the nozzle may use a fine nozzle. The sample NMP provided from the sample NMP storage unit (310) is transferred through the cylinder, and the cylinder may be pumped by the movement of the piston. The fine nozzle is located between the cylinder and the NMP container, and allows the sample NMP output from the cylinder to be transferred to the NMP container through the fine nozzle.

[0060] The sample NMP inspection unit (330) analyzes the components of NMP using the sample NMP stored in the sample NMP container and transmits the analysis data to the control unit (150). For example, the sample NMP inspection unit (330) can inspect the moisture content, particle content, etc. contained in the sample NMP.

[0061] The sample NMP container storage unit (340) stores sample NMP containers that have been inspected in the sample NMP inspection unit (330). The sample NMP containers are stored in a predetermined amount in the sample NMP container storage unit (340) and then discharged to the outside at predetermined intervals.

[0062]

[0063] Figure 4 is a flowchart for explaining the operation of an NMP purification system according to one embodiment of the present invention.

[0064] Referring to FIG. 4, waste NMP gas generated in the secondary battery production process is captured in the booster fan unit (200) and provided to the waste NMP gas adsorption unit (210) (400), and the waste NMP gas adsorption unit (210) adsorbs the waste NMP gas and converts it into liquid (410). Thereafter, the first purification unit (230) separates distilled water and waste NMP from the liquid waste NMP (420), and the waste NMP from which the distilled water has been separated is purified in the second to fourth purification units (260, 270, 280) (430). The purified NMP is provided so that it can be reused in the secondary battery production process (440), and the purified NMP can be exported to the outside and used for other purposes.

[0065] Meanwhile, although the detailed description of the present invention has described specific embodiments, it is obvious that various modifications are possible within the scope of the present invention.

[0066] Therefore, the scope of the present invention is not limited to the described embodiments, but should be determined not only by the scope of the claims described below but also by equivalents of the scope of the claims.

Claims

1. In the NMP purification system, A first module section including a booster fan section for capturing waste NMP gas and a waste NMP gas adsorption section for absorbing the waste NMP gas and converting it into a waste NMP solution; A second module section adjacent to the first module section and including a DI water supply section for supplying DI water used in the closed NMP gas adsorption section; A third module section adjacent to the second module section and including a first purification section for purifying a waste NMP solution supplied from the first module section by permeation evaporation; A fourth module section adjacent to the third module section and including a second purification section for purifying a purified NMP solution supplied from the third module section by distillation, and a third purification section for purifying the NMP solution purified in the second purification section by distillation; An NMP purification system comprising a fifth module section, which is adjacent to the fourth module section and includes a fourth purification section for purifying a purified NMP solution supplied from the fourth module section by vaporization.

2. In paragraph 1, It further includes a first module connecting portion for connecting neighboring modules between the first to fifth module portions; The above first module connecting part is an NMP purification system in which a module fixing part provided on the frame on the outer surface of each of the first to fifth module parts is aligned with a module fixing plate, a fixing pad is added, and then a bolt is connected.

3. In paragraph 1, Each of the first to fifth module sections includes a fixing section for fixing a device for NMP purification located inside each module; Each module section includes a ground connection section for installing each module on the ground; An NMP purification system in which the above-mentioned ground connection part is installed on the ground and connected to a second module connection part for installing and fixing each module part on the ground.

4. In paragraph 1, An NMP purification system, wherein the third module section includes a first inspection section that inspects the state of the NMP solution purified in the first purification section using a spectroscopic method.

5. In paragraph 4, The above first inspection section inspects the moisture content contained in the purified NMP, The above first purification unit is an NMP purification system that re-purifies purified NMP when the moisture content contained in the purified NMP exceeds a preset moisture content.

6. In paragraph 1, An NMP purification system, wherein the fifth module section includes a second inspection section for collecting a sample of the NMP solution purified in the fourth purification section and examining it using a component analysis method to analyze the state of the NMP solution purified in the fourth purification section.

7. In paragraph 6, The second inspection section includes a sample NMP storage section for storing a predetermined amount of sample NMP; A sample NMP inlet for injecting a predetermined amount of sample NMP supplied from the outside into the sample NMP storage unit; A sample NMP transfer unit for transferring the sample NMP from the sample NMP storage unit to a sample NMP container; A sample NMP inspection unit for analyzing the components of the sample NMP stored in the above sample NMP container; An NMP purification system comprising a sample NMP container storage unit for storing the above sample NMP container.

8. In paragraph 1, An NMP purification system that further purifies NMP purified in at least one of the second to fourth purification units by using at least one of the moisture content contained in the NMP purified in the fourth purification unit or the purity of the purified NMP.

9. In paragraph 1, The second and third purification units use a distillation tower to purify the purified NMP solution supplied from the third module unit. An NMP purification system in which vaporized water is positioned at the top of the distillation tower used in the second purification unit and purified NMP is positioned at the bottom, and vaporized NMP is positioned at the top of the distillation tower used in the third purification unit and impurities are positioned at the bottom.

10. In paragraph 1, The fourth purification unit is an NMP purification system that allows moisture to evaporate as the purified NMP solution supplied from the fourth module unit passes through a passage of a predetermined length.

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