Apparatus for pervaporation treatment of acrylonitrile removal of polymerization inhibitors

Abstract

The utility model belongs to chemical purification device technical field, concretely relates to a kind of acrylonitrile removal polymerization inhibitor pervaporation treatment device.Propylene cyanamide removal polymerization inhibitor pervaporation treatment device, including propylene cyanamide storage tank, membrane module, cooler, condenser;Propylene cyanamide storage tank bottom discharge line is connected with precision filter, and precision filter is connected with membrane module, and the gas phase discharge port of membrane module is connected with condenser, and the liquid phase discharge port of membrane module is connected with polymerization inhibitor enrichment tank, and the bottom discharge pipe of polymerization inhibitor enrichment tank is divided into two ways;The gas phase outlet of the top of propylene cyanamide storage tank, polymerization inhibitor enrichment tank, polymerization inhibitor purification tank is connected with cooler;The liquid phase outlet of cooler, condenser is connected with polymerization inhibitor purification tank;Nitrogen pipeline and vacuum unit are also provided.The acrylonitrile removal polymerization inhibitor pervaporation treatment device provided by the utility model is adapted to carbon fiber propylene cyanamide intermittent treatment condition, and MEHQ can be stably reduced to below 1ppm.

Description

Technical Field

[0001] This utility model belongs to the technical field of chemical purification equipment, specifically relating to a pervaporation treatment device for removing polymerization inhibitors from acrylonitrile. Background Technology

[0002] To prevent self-polymerization during storage and transportation, 35-50 ppm of p-hydroxyanisole (MEHQ) is added as a polymerization inhibitor to the industrial acrylonitrile raw material used in carbon fiber production. Current carbon fiber precursor preparation processes do not remove this polymerization inhibitor from acrylonitrile. The inhibitor interferes with polymerization initiation, disrupts molecular chain regularity, introduces trace impurities, and reduces the electrical or mechanical stability of the material. Removing the inhibitor to below 1 ppm allows for a controllable, high-conversion, and low-defect polymerization process, meeting the stringent purity requirements of high-end materials. High-purity acrylonitrile can be used in the production of high-performance carbon fibers, special resins for electronic packaging, flexible electronic substrate films, high-end targeted drugs, and optical-grade transparent resins. Currently, the mainstream processes for removing MEHQ polymerization inhibitors in the industry are mainly divided into three categories: distillation purification, adsorption column adsorption, and conventional pervaporation separation.

[0003] The core configuration of the traditional vacuum distillation process for removing polymerization inhibitors includes a distillation column, reboiler, overhead condenser, reflux pump, and vacuum system. It relies on the boiling point difference between MEHQ and acrylonitrile to achieve separation through high-temperature vaporization of acrylonitrile and retention of the polymerization inhibitor in the reboiler. This process operates at temperatures close to the boiling point of acrylonitrile (77.3℃), which easily triggers acrylonitrile self-polymerization, causing blockage of the trays and heat exchangers, making it unsuitable for intermittent start-stop operations. Furthermore, the reboiler's steam heating energy consumption is high, resulting in poor economic efficiency for small-scale intermittent processing. The system also lacks airtight protection, making it susceptible to increased oxidative polymerization and equipment fouling upon contact with air. It is only suitable for high-flow continuous feed; in intermittent carbon fiber feeding scenarios, start-stop losses are significant and operations are cumbersome.

[0004] The solid adsorption depolymerization process mainly consists of an adsorption tower, a transfer pump, a regeneration heating system, and a rinsing tank. It utilizes polar packing materials such as molecular sieves and activated alumina to adsorb and remove MEHQ polymerization inhibitors. This process has significant limitations: the packing material has a limited adsorption capacity, requiring frequent regeneration when the MEHQ concentration in the raw material is 35-50 ppm. The high-temperature heating and solvent rinsing during regeneration generate large amounts of hazardous waste, and the high-temperature conditions can easily trigger acrylonitrile polymerization within the tower, shortening the packing material's lifespan. Furthermore, this process cannot consistently control MEHQ below 1 ppm; after adsorption saturation, the output indicators rebound rapidly, and the packing material is prone to detachment, generating micro-impurities that can be carried into downstream processes, affecting the quality of the carbon fiber precursor.

[0005] Conventional single-stage pervaporation units are equipped with only a single membrane module, a simple vacuum unit, and a cooling collection tank. They rely on the sieving action of polar membranes to separate materials, lacking closed-loop circulation, comprehensive temperature control, and a complete nitrogen blanketing protection system. Existing equipment has low separation efficiency, and the material cannot consistently achieve the MEHQ ≤ 1ppm target in a single membrane pass, resulting in low membrane element utilization.

[0006] Patent CN102199104A discloses an acrylonitrile distillation purification device that relies on high-temperature separation of the distillation column to remove polymerization inhibitors and impurities from the raw materials. This device can only operate continuously at a high flow rate and is prone to acrylonitrile self-polymerization and high energy consumption under high-temperature conditions. It does not meet the production requirements of the carbon fiber industry for intermittent low-temperature and precise removal of trace amounts of polymerization inhibitors, and cannot solve the problem of insufficient material polymerization and separation efficiency under intermittent start-stop conditions. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the fact that existing distillation, adsorption and conventional pervaporation equipment cannot simultaneously meet the multiple industrial requirements of low temperature oxygen-free anti-self-polymerization, intermittent stable operation, deep removal of trace amounts of MEHQ, low energy consumption and easy maintenance of membrane components. It provides an acrylonitrile removal inhibitor pervaporation treatment device, which is suitable for the intermittent treatment of acrylonitrile in carbon fiber and can stably reduce MEHQ to below 1ppm.

[0008] This utility model discloses an acrylonitrile removal inhibitor pervaporation treatment device, comprising an acrylonitrile storage tank, a membrane module, a cooler, and a condenser. The bottom outlet pipe of the acrylonitrile storage tank is divided into two branches: one branch connects to a No. 1 precision filter via a pipeline, which in turn connects to an inhibitor concentration tank via a pipeline; the other branch connects to a No. 2 precision filter via a pipeline, which in turn connects to the membrane module. The gas phase outlet of the membrane module is connected to the condenser, and the liquid phase outlet of the membrane module is connected to the inhibitor concentration tank. The bottom outlet pipe of the inhibitor concentration tank is divided into two branches: one branch connects to the acrylonitrile storage tank, and the other branch connects to an inhibitor purification tank. The gas phase outlets at the top of the acrylonitrile storage tank, the inhibitor concentration tank, and the inhibitor purification tank are connected to the cooler via pipelines. The liquid phase outlets of the cooler and the condenser are connected to the inhibitor purification tank via pipelines. Nitrogen pipelines are installed on both the acrylonitrile storage tank and the membrane module inlet pipes. The acrylonitrile storage tank, the polymerization inhibitor concentration tank, and the polymerization inhibitor purification tank are connected to the cooler via parallel pipelines, and the cooler is connected to the vacuum unit via vacuum pipelines.

[0009] A No. 2 acrylonitrile transfer pump is installed between the acrylonitrile storage tank and the No. 1 precision filter.

[0010] An acrylonitrile transfer pump is installed between the acrylonitrile storage tank and the No. 2 precision filter.

[0011] A No. 1 concentration transfer pump is installed between the bottom discharge pipe of the polymerization inhibitor concentration tank and the acrylonitrile storage tank.

[0012] A No. 2 concentration transfer pump is installed between the bottom discharge pipe of the polymerization inhibitor concentration tank and the polymerization inhibitor purification tank.

[0013] The bottom discharge pipeline of the polymerization inhibitor purification tank is divided into two lines. One line is connected to the acrylonitrile pipeline through the No. 2 purification delivery pump, and the other line is connected to the inlet of the polymerization inhibitor concentration tank through the No. 1 purification delivery pump.

[0014] The cooler is equipped with pipes that are connected to the cold brine recovery pipe and the cold brine supply pipe, respectively.

[0015] The condenser is equipped with pipes that connect to the cold brine recovery pipe and the cold brine supply pipe, respectively.

[0016] The cooler is configured with one standby unit.

[0017] In the process of purifying acrylonitrile, the acrylonitrile raw material in the acrylonitrile storage tank is transported to the precision filter by the acrylonitrile transfer pump No. 1. The filtered raw material enters the membrane module for pervaporation. The vaporized material enters the condenser 8 for condensation. The condensed material enters the polymerization inhibitor purification tank and is transported to the outside by the purification transfer pump No. 2.

[0018] To improve the permeation efficiency of acrylonitrile, after pervaporation through the membrane module, a large amount of acrylonitrile liquid returns to the inhibitor concentration tank, and is pumped back to the acrylonitrile storage tank by the No. 1 concentration transfer pump. The material in the acrylonitrile storage tank is then transported to the No. 2 precision filter. The filtered raw material enters the membrane module for pervaporation, and this cycle continues. After each pervaporation through the membrane module, the concentration of the inhibitor in the inhibitor concentration tank gradually increases.

[0019] During the acrylonitrile purification process, the vacuum unit is turned on to provide a vacuum environment through the vacuum pipeline. The top pipeline of the polymerization inhibitor purification tank is connected to the shell side of the cooler, and the shell side of the cooler is connected to the vacuum pipeline to provide a vacuum environment.

[0020] Because polymerization reactions are generally batch-based, the acrylonitrile used to remove the polymerization inhibitor needs to be supplied intermittently, with supply interruptions ranging from 8 to 24 hours. To prevent acrylonitrile self-polymerization within the inhibitor purification tank, the material from the inhibitor purification tank is transferred to the inhibitor concentration tank via a purification transfer pump (No. 1). The top valves of the acrylonitrile storage tank and the inhibitor concentration tank are opened, allowing the gaseous phase to be discharged through pipelines to the shell side of the cooler, then connected to the vacuum pipeline, and discharged together into the tail gas treatment device. The liquid phase is discharged through pipelines to the inhibitor purification tank for recovery. This method inhibits acrylonitrile self-polymerization in a short period of time.

[0021] During prolonged shutdowns, the acrylonitrile storage tank is pumped by a No. 1 acrylonitrile transfer pump to a No. 1 precision filter for filtration. The filtered material then enters the polymerization inhibitor concentration tank, and is then pumped by a No. 2 concentration transfer pump to the polymerization inhibitor purification tank. The mixed material is then pumped by a No. 1 purification transfer pump to the polymerization inhibitor concentration tank. This cycle continues until the fully mixed material is finally pumped from the polymerization inhibitor concentration tank to the acrylonitrile tank via a No. 1 concentration transfer pump for recycling.

[0022] The entire operating system achieves a nitrogen-sealed, oxygen-free environment through nitrogen pipelines and a vacuum unit, preventing acrylonitrile self-polymerization.

[0023] Compared with the prior art, the beneficial effects of this utility model are: (1) This utility model adopts membrane module pervaporation separation technology and combines nitrogen pipeline to continuously fill the pipeline and equipment with nitrogen, thus constructing a complete closed nitrogen sealing protection system, realizing the removal of polymerization inhibitor under low temperature and oxygen-free conditions, effectively avoiding the problem of acrylonitrile self-polymerization at high temperature and oxidative polymerization in air, significantly improving the safety of the device operation, and overcoming the defects of traditional distillation process being prone to self-polymerization at high temperature and adsorption process being prone to polymerization during high temperature regeneration.

[0024] (2) This utility model connects the gas phase outlet of the membrane module to the condenser and the liquid phase outlet to the inhibitor concentration tank. A portion of the material at the bottom of the inhibitor concentration tank is sent back to the acrylonitrile storage tank for recycling and reprocessing via the No. 1 concentration conveying pump, forming a closed-loop circulation separation system. This system can stably remove MEHQ inhibitor to below 1ppm, solving the problems of low separation efficiency and inability to stably meet the standard in a single membrane pass of conventional single-stage pervaporation devices. This system meets the strict requirements of carbon fiber production for the deep removal of trace inhibitors.

[0025] (3) The device of this utility model has a compact structure and flexible operation, which is suitable for the intermittent feeding and frequent start-stop working conditions of the carbon fiber industry. At the same time, the cooler adopts a one-for-one standby setting, which can realize continuous operation without stopping the machine. Moreover, the pervaporation process does not require high temperature heating, and the energy consumption is significantly reduced compared with the traditional distillation process. The membrane module is easy to maintain and replace, and the overall economic efficiency is significantly better than the existing distillation, adsorption and conventional pervaporation equipment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the acrylonitrile polymerization inhibitor removal pervaporation treatment device of this utility model.

[0027] In the diagram: 1. Acrylonitrile storage tank; 2. Acrylonitrile transfer pump #1; 3. Acrylonitrile transfer pump #2; 4. Precision filter #1; 5. Precision filter #2; 6. Membrane module; 7. Cooler; 8. Condenser; 9. Concentration transfer pump #1; 10. Concentration transfer pump #2; 11. Inhibitor concentration tank; 12. Inhibitor purification tank; 13. Purification transfer pump #1; 14. Purification transfer pump #2; 15. Nitrogen pipeline; 16. Cold brine recovery pipe; 17. Cold brine supply pipe; 18. Vacuum pipeline; 19. Acrylonitrile pipeline. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] The acrylonitrile storage tank 1, the polymerization inhibitor concentration tank 11, and the polymerization inhibitor purification tank 12 of this utility model are all made of electronic grade 316L stainless steel.

[0030] like Figure 1 As shown, the acrylonitrile removal inhibitor pervaporation treatment device of this utility model includes an acrylonitrile storage tank 1, a membrane module 6, a cooler 7, and a condenser 8. The bottom discharge pipeline of the acrylonitrile storage tank 1 is divided into two lines. One line is connected to a No. 1 precision filter 4 via a pipeline, and the No. 1 precision filter 4 is connected to the inhibitor concentration tank 11 via a pipeline. The other line is connected to a No. 2 precision filter 5 via a pipeline, and the No. 2 precision filter 5 is connected to the membrane module 6. The gas phase outlet of the membrane module 6 is connected to the condenser 8. The liquid phase outlet of the membrane module 6... The discharge port is connected to the polymerization inhibitor concentration tank 11. The bottom discharge pipe of the polymerization inhibitor concentration tank 11 is divided into two paths, one connected to the acrylonitrile storage tank 1 and the other connected to the polymerization inhibitor purification tank 12. The gas phase outlets at the top of the acrylonitrile storage tank 1, the polymerization inhibitor concentration tank 11, and the polymerization inhibitor purification tank 12 are connected to the cooler 7 through pipelines. The liquid phase outlets of the cooler 7 and the condenser 8 are connected to the polymerization inhibitor purification tank 12 through pipelines. Nitrogen pipelines 15 are provided on the inlet pipes of the acrylonitrile storage tank 1 and the membrane module 6. The acrylonitrile storage tank 1, the polymerization inhibitor concentration tank 11, and the polymerization inhibitor purification tank 12 are connected to the cooler 7 through parallel pipelines, and the cooler 7 is connected to the vacuum unit through the vacuum pipeline 18.

[0031] A 2# acrylonitrile transfer pump 3 is installed between the acrylonitrile storage tank 1 and the 1# precision filter 4. The transfer pump is preferably a magnetic pump.

[0032] An acrylonitrile transfer pump 2 is installed between the acrylonitrile storage tank 1 and the precision filter 5.

[0033] A No. 1 concentration transfer pump 9 is installed between the bottom discharge pipe of the polymerization inhibitor concentration tank 11 and the acrylonitrile storage tank 1.

[0034] A No. 2 concentration transfer pump 10 is installed between the bottom discharge pipe of the polymerization inhibitor concentration tank 11 and the polymerization inhibitor purification tank 12.

[0035] The bottom discharge pipeline of the polymerization inhibitor purification tank 12 is divided into two lines. One line is connected to the acrylonitrile pipeline 19 through the No. 2 purification transfer pump 14, and the other line is connected to the inlet of the polymerization inhibitor concentration tank 11 through the No. 1 purification transfer pump 13.

[0036] The cooler 7 is equipped with pipes that are connected to the cold brine recovery pipe 16 and the cold brine supply pipe 17 respectively.

[0037] The condenser 8 is equipped with pipes that are connected to the cold brine recovery pipe 16 and the cold brine supply pipe 17 respectively.

[0038] The cooler 7 adopts a one-for-one standby configuration. That is, two coolers 7 are installed, one operating normally and the other as a backup. When the operating cooler 7 needs to be inspected or maintained, it can be switched to the standby cooler 7 to continue working, ensuring the continuous and stable operation of the device and avoiding the shutdown of the entire device due to cooler failure.

[0039] The acrylonitrile storage tank 1 is used to store acrylonitrile raw materials to be processed.

[0040] Precision filters 4 (No. 1) and 5 (No. 2) are used for pre-filtration of acrylonitrile feedstock to remove solid particulate impurities, preventing clogging or damage to the subsequent membrane module 6 and ensuring its normal operation and service life. The precision filters have a filtration accuracy of 0.1 μm (100 nm).

[0041] Membrane module 6 is the core component of pervaporation separation. The membrane thickness is 80~200μm, and a sub-nanometer (0.1nm≤) pervaporation membrane is purchased to meet the requirement of MEHQ content ≤1ppm after removal. The feed inlet of membrane module 6 is connected to precision filter 5 (No. 2), and the filtered acrylonitrile enters membrane module 6 for pervaporation separation. Membrane module 6 adopts a plate-and-frame structure or a multi-stage spiral wound structure, and the membrane material is a pervaporation membrane. Under vacuum conditions, heavy components such as polymerization inhibitors in acrylonitrile are retained by the membrane, while light components such as acrylonitrile permeate through the membrane layer and are discharged as gas from the gas phase outlet of membrane module 6; the liquid phase material containing polymerization inhibitors that cannot permeate through the membrane is discharged from the liquid phase outlet of membrane module 6. The gas phase outlet of membrane module 6 is connected to condenser 8, and the liquid phase outlet of membrane module 6 is connected to inhibitor concentration tank 11.

[0042] The vacuum unit provides the required vacuum environment for the entire system through the cooler 7, enabling the membrane module 6 to undergo pervaporation separation under vacuum conditions, thereby improving separation efficiency.

[0043] When this utility model is in operation: (1) Normal purification conditions: The acrylonitrile raw material to be processed in acrylonitrile storage tank 1 is transported to precision filter 5 via acrylonitrile transfer pump 2 (1#). After solid particulate impurities are removed by 0.1μm precision filtration, it enters membrane module 6 for pervaporation separation. Under the vacuum environment provided by the vacuum unit, the light component of acrylonitrile permeates through the pervaporation membrane and is discharged from the gas phase outlet of membrane module 6 in gas phase form. It enters condenser 8 and is cooled and condensed by cold brine. The liquid phase material enters the polymerization inhibitor purification tank 12 for collection, finally obtaining a high-purity acrylonitrile product with MEHQ content ≤1ppm. This product is then transported to the outside for use in carbon fiber production by purification transfer pump 14 (2#) via acrylonitrile pipeline 19. The heavy component liquid phase material containing polymerization inhibitor that cannot permeate the membrane enters the polymerization inhibitor concentration tank 11 from the liquid phase outlet of membrane module 6.

[0044] Meanwhile, to improve the concentration efficiency of the polymerization inhibitor and achieve deep removal, the material containing the polymerization inhibitor enriched in the polymerization inhibitor concentration tank 11 is sent back to the acrylonitrile storage tank 1 via the No. 1 concentration transfer pump 9. After being mixed with fresh raw materials, it is again transported via the No. 1 acrylonitrile transfer pump 2 to the No. 2 precision filter 5 and membrane module 6 for circulating pervaporation treatment. Through the above cycle, the polymerization inhibitor is gradually concentrated in the polymerization inhibitor concentration tank 11, while the permeate side of the membrane module 6 continuously produces high-purity acrylonitrile with low polymerization inhibitor content, ensuring that the system can stably remove MEHQ to below 1 ppm for a long period of time.

[0045] (2) Stoppage and intermittent operation conditions: When the unit is temporarily shut down or after a batch of intermittent polymerization reaction feed is completed, to prevent residual acrylonitrile from self-polymerizing due to lack of polymerization inhibitor, the top gas phase valve of acrylonitrile storage tank 1 and the top gas phase valve of inhibitor concentration tank 11 are opened. The residual gas phase material in the system is discharged to the shell side of cooler 7 through pipeline, and then discharged into the tail gas treatment device through vacuum pipeline 18. During intermittent or short-term shutdowns of the polymerization reaction, the acrylonitrile purified in inhibitor purification tank 12 can be returned to inhibitor concentration tank 11. For long-term shutdowns, the materials in acrylonitrile storage tank 1, inhibitor concentration tank 11, and inhibitor purification tank 12 and the connecting pipelines must be thoroughly mixed and eventually returned to acrylonitrile storage tank 1.

[0046] (3) Nitrogen blanketing protection condition: Throughout the operation, nitrogen pipeline 15 continuously injects high-purity nitrogen into the acrylonitrile storage tank 1 and the feed inlet pipeline of membrane module 6, etc. In conjunction with the vacuum unit and cooler 7, continuous vacuuming and exhausting of the gas phase space at the top of acrylonitrile storage tank 1, polymerization inhibitor concentration tank 11, and polymerization inhibitor purification tank 12, a completely sealed nitrogen-sealed oxygen-free environment is constructed for the entire system. This isolates oxygen from the source, effectively preventing acrylonitrile from undergoing oxidative polymerization or thermal self-polymerization under different operating conditions, and ensuring the safe and stable operation of the equipment.

[0047] (4) Cooling and condensation cycle operation: Cooler 7 circulates cold brine through cold brine supply pipe 17 and cold brine recovery pipe 16 to cool the gas phase discharged from the top of acrylonitrile storage tank 1, inhibitor concentration tank 11, and inhibitor purification tank 12. Similarly, condenser 8 circulates cold brine through cold brine supply pipe 17 and cold brine recovery pipe 16 to condense and collect the permeate gas phase discharged from the gas phase outlet of membrane module 6. Coolers 7 are configured with one standby unit; during normal operation, only one unit is in use, while the other is on standby. When cooler 7 requires maintenance, it can be switched to the standby cooler 7 to continue operation, ensuring continuous operation of the unit without shutdown.

Claims

1. A pervaporation treatment device for removing polymerization inhibitors from acrylonitrile, characterized in that: The system includes an acrylonitrile storage tank (1), a membrane module (6), a cooler (7), and a condenser (8). The bottom discharge pipeline of the acrylonitrile storage tank (1) is divided into two lines. One line is connected to the No. 1 precision filter (4) via a pipeline, and the No. 1 precision filter (4) is connected to the polymerization inhibitor concentration tank (11) via a pipeline. The other line is connected to the No. 2 precision filter (5) via a pipeline, and the No. 2 precision filter (5) is connected to the membrane module (6). The gas phase outlet of the membrane module (6) is connected to the condenser (8), and the liquid phase outlet of the membrane module (6) is connected to the polymerization inhibitor concentration tank (11). 1) Connection: The bottom outlet pipe of the polymerization inhibitor concentration tank (11) is divided into two paths, one of which is connected to the acrylonitrile storage tank (1) and the other is connected to the polymerization inhibitor purification tank (12); the gas phase outlets at the top of the acrylonitrile storage tank (1), the polymerization inhibitor concentration tank (11), and the polymerization inhibitor purification tank (12) are connected to the cooler (7) through pipelines; the liquid phase outlets of the cooler (7) and the condenser (8) are connected to the polymerization inhibitor purification tank (12) through pipelines; nitrogen pipelines (15) are provided on the inlet pipes of the acrylonitrile storage tank (1) and the membrane module (6); The acrylonitrile storage tank (1), the polymerization inhibitor concentration tank (11), and the polymerization inhibitor purification tank (12) are connected to the cooler (7) through parallel pipelines, and the cooler (7) is connected to the vacuum unit through the vacuum pipeline (18).

2. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 1, characterized in that: A 2# acrylonitrile transfer pump (3) is installed between the acrylonitrile storage tank (1) and the 1# precision filter (4).

3. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 2, characterized in that: An acrylonitrile transfer pump (2) is installed between the acrylonitrile storage tank (1) and the precision filter (5).

4. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 1, characterized in that: A No. 1 concentration transfer pump (9) is installed between the bottom discharge pipe of the polymerization inhibitor concentration tank (11) and the acrylonitrile storage tank (1).

5. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 4, characterized in that: A No. 2 concentration transfer pump (10) is installed between the bottom discharge pipe of the polymerization inhibitor concentration tank (11) and the polymerization inhibitor purification tank (12).

6. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 1, characterized in that: The bottom discharge pipeline of the polymerization inhibitor purification tank (12) is divided into two paths. One path is connected to the acrylonitrile pipeline (19) through the No. 2 purification transfer pump (14), and the other path is connected to the inlet of the polymerization inhibitor concentration tank (11) through the No. 1 purification transfer pump (13).

7. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 1, characterized in that: The cooler (7) is equipped with pipes that connect to the cold brine recovery pipe (16) and the cold brine supply pipe (17).

8. The acrylonitrile polymerization inhibitor removal pervaporation treatment device according to claim 1, characterized in that: The condenser (8) is equipped with pipes that connect to the cold brine recovery pipe (16) and the cold brine supply pipe (17).

9. The acrylonitrile removal inhibitor pervaporation treatment apparatus according to any one of claims 1-8, characterized in that: The cooler (7) is configured with one standby unit.

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