Solvent recovery system for polyphenylene sulfide polymerization device

Abstract

The utility model discloses a solvent recovery system for a polyphenylene sulfide polymerization device. The solvent recovery system comprises a spray scraper condenser, a liquid seal tank, a circulating pump and a heat exchanger, the spraying scraper condenser is provided with an NMP gas inlet, a spraying liquid inlet and a scraper device, and impurity blockage can be prevented. And the liquid seal tank is communicated with the condenser through an atmosphere leg, is internally provided with a filter screen and is provided with an oligomer outlet at the bottom. The circulating pump is used for conveying liquid, and the heat exchanger can adjust the spraying liquid temperature. A gap between a spiral scraper of the scraper device and the inner wall of the condenser is reasonable, and the material is wear-resistant and corrosion-resistant. And the spraying liquid inlet is connected with the spraying distributor, so that the spraying is more uniform. A liquid level sensor is arranged in the liquid seal tank to control the flow of the circulating pump. The system can efficiently recover the solvent, solves the problems that a condenser of an existing system is easy to block, low in recovery efficiency and the like, is stable and reliable in operation, and has good economic benefits and practical values.

Description

TECHNICAL FIELD

[0001] The utility model relates to chemical product production technical field, concretely relates to a kind of solvent recovery system for polyphenyl sulfide polymerization device, mainly applied to solvent recovery link in the polymerization production process of polyphenyl sulfide (PPS) with N - methylpyrrolidone (NMP) as solvent production. BACKGROUND

[0002] In the production process of polyphenyl sulfide, solvent recovery process is an important link. Among them, N - methylpyrrolidone as common solvent, improve its recovery rate and quality play a key role in reducing the cost of polyphenyl sulfide production.

[0003] At present, the solvent recovery process of prior art is usually after the completion of final shrinkage kettle reaction, the mixture of polyphenyl sulfide product and N - methylpyrrolidone solvent is transported to flash evaporation equipment for flash evaporation operation. Gaseous solvent flashed out can be cooled through column tube type heat exchanger, and then liquid N - methylpyrrolidone formed after cooling is recovered. However, this traditional process has obvious defects. Since the mixture of high pressure and high temperature polyphenyl sulfide product and N - methylpyrrolidone solvent enters the flash evaporation equipment from the reaction kettle, N - methylpyrrolidone solvent will vaporize instantly, and this process will bring out a large amount of small molecule polyphenyl sulfide. These small molecule polyphenyl sulfide enter column tube type heat exchanger, which is easy to cause heat exchanger blockage. Once the heat exchanger is blocked, not only the cooling effect is affected, the solvent recovery efficiency is reduced, but also frequent shutdown is needed for cleaning and maintenance, which increases production cost and seriously affects the continuity and stability of production. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a kind of solvent recovery system for polyphenyl sulfide polymerization device, to solve the problem that cooler is prone to block in the existing solvent recovery process, ensure that solvent recovery process can be stably and efficiently carried out, reduce production cost, improve production efficiency.

[0005] The technical scheme that the utility model solves the above technical problem is as follows: a kind of solvent recovery system for polyphenyl sulfide polymerization device, comprising:

[0006] Spray scraper condenser, spray scraper condenser is equipped with NMP gas inlet, spray liquid inlet, scraper device is arranged in the inside of spray scraper condenser;NMP gas containing generated from polyphenyl sulfide polymerization device enters spray scraper condenser through NMP gas inlet, and the spray liquid for cooling and absorbing NMP enters from spray liquid inlet. Scraper device can effectively scrape the impurities adhered on the inner wall of condenser, to prevent its accumulation from causing condenser blockage;

[0007] The liquid seal groove is communicated with the bottom of the spray blade condenser through an atmosphere leg at the top of the liquid seal groove, and a filter screen is arranged in the liquid seal groove; the liquid and impurity mixture treated by the spray blade condenser flows into the liquid seal groove through the atmosphere leg, and the filter screen can filter out impurities such as small molecule oligomers in the liquid, so that the liquid flowing out of the liquid seal groove is more pure;

[0008] The circulating pump is connected with the outlet of the liquid seal groove; and the circulating pump is used to deliver the filtered liquid in the liquid seal groove to the heat exchanger;

[0009] The heat exchanger is connected with the outlet of the circulating pump at the inlet, and connected with the spray liquid inlet of the spray blade condenser at the outlet. The liquid flowing out of the liquid seal groove enters the heat exchanger for cooling or heating under the action of the circulating pump, and then returns to the spray blade condenser as spray liquid for recycling after being adjusted to a suitable temperature.

[0010] As a preferred solution of the solvent recovery system for the polyphenylene sulfide polymerization device, the scraper device includes a rotating shaft and a spiral scraper, and the spiral scraper is arranged along the inner wall of the spray blade condenser, and the gap between the spiral scraper and the inner wall of the spray blade condenser is 1-3 mm. This structure design enables the spiral scraper to fully scrape off the impurities on the inner wall during rotation, while avoiding excessive friction with the inner wall to damage the equipment.

[0011] As a preferred solution of the solvent recovery system for the polyphenylene sulfide polymerization device, the bottom of the liquid seal groove is provided with an oligomer discharge outlet, and the oligomer discharge outlet is connected with a control valve. The control valve can periodically discharge the accumulated oligomers in the liquid seal groove, ensuring the normal operation of the liquid seal groove and the filtering effect of the filter screen.

[0012] As a preferred solution of the solvent recovery system for the polyphenylene sulfide polymerization device, the heat exchanger is a plate heat exchanger, and a temperature sensor is arranged at the inlet and outlet of the heat exchange medium of the heat exchanger. The plate heat exchanger has the advantages of high heat transfer efficiency and compact structure, and the temperature sensor can monitor the temperature of the heat exchange medium in real time, so as to timely adjust the operating parameters of the heat exchanger and ensure the stability of the spray liquid temperature.

[0013] As a preferred solution of the solvent recovery system for the polyphenylene sulfide polymerization device, the spray liquid inlet of the spray blade condenser is connected with a spray distributor. The spray distributor can make the spray liquid more uniformly distributed in the condenser, increase the contact area between the spray liquid and the NMP gas, and improve the cooling and absorption effect.

[0014] As a preferred solution of the solvent recovery system for the polyphenylene sulfide polymerization device, the material of the spiral scraper is polytetrafluoroethylene coated stainless steel with a thickness of 5-8 mm. The polytetrafluoroethylene coated stainless steel has good corrosion resistance and wear resistance, and can adapt to harsh working environment, prolonging the service life of the spiral scraper.

[0015] As a polyphenyl sulfide polymerization device solvent recovery system preferred solution, liquid seal tank is equipped with liquid level sensor, liquid level sensor and circulating pump frequency converter electric connection, liquid level sensor is used for controlling the flow of circulating pump. The liquid level sensor can monitor the liquid level in the liquid seal tank in real time, and control the flow of the circulating pump according to the liquid level, realize the automatic control and stable operation of the system.

[0016] The beneficial effects of the utility model are as follows: first, the anti-blocking performance is good: through the scraper device in the spray condenser, the impurities on the inner wall of the condenser can be scraped in time, the blockage of the condenser is effectively avoided, the continuous and stable operation of the system is ensured, and the equipment maintenance cost and downtime are reduced.

[0017] Second, the solvent recovery efficiency is high: the filter screen in the liquid seal tank can effectively filter impurities, improve the purity of the recovered solvent; the spray distributor makes the spray liquid uniformly distributed, increases the contact area with NMP gas, improves the cooling and absorption effect, and thus improves the recovery efficiency of the solvent.

[0018] Third, stable and reliable operation: the heat exchanger adopts plate heat exchanger and is equipped with temperature sensor, which can accurately control the temperature of the spray liquid; the linkage control of liquid level sensor and circulating pump frequency converter can automatically adjust the circulating pump flow according to the liquid level of liquid seal tank, which ensures the stability and reliability of system operation.

[0019] Fourth, long service life of equipment: the spiral scraper is made of polytetrafluoroethylene coated stainless steel, which has good corrosion resistance and wear resistance, prolongs the service life of the scraper and reduces the replacement cost of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of embodiments or prior art. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0021] The structure, proportion, size and the like shown in the specification are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the limiting conditions of the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0022] Figure 1 The utility model discloses a polyphenyl sulfide polymerization device solvent recovery system structure schematic diagram provided in the embodiment.

[0023] In the figure, 1, spray blade condenser; 11, NMP gas inlet; 12, spray liquid inlet; 13, scraper device; 131, rotating shaft; 132, spiral scraper; 14, atmospheric leg; 2, liquid seal groove; 21, filter screen; 22, oligomer discharge port; 3, circulating pump; 4, heat exchanger; 15, spray distributor. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purpose, features and advantages of the utility model more apparent, obvious and easy to understand, the specific embodiments of the utility model are described in detail below. In the following description, a lot of specific details are set forth in order to give a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs. The terms used in the specification of the utility model are only for the purpose of describing specific embodiments and are not intended to limit the utility model.

[0026] Referring to Figure 1 The utility model embodiment provides a kind of solvent recovery system for polyphenyl sulfide polymerization device, it include:

[0027] Spray blade condenser 1, spray blade condenser 1 is equipped with NMP gas inlet 11, spray liquid inlet 12, spray blade condenser 1 is internally provided with scraper device 13;NMP gas containing generated from polyphenyl sulfide polymerization device enters spray blade condenser 1 by NMP gas inlet 11, and the spray liquid for cooling and absorbing NMP enters from spray liquid inlet 12.Scraper device 13 can effectively scrape the impurities adhered on the inner wall of condenser, prevent its accumulation and cause condenser to be blocked.

[0028] Specifically, in the production process of polyphenylene sulfide polymer, high-temperature gas containing NMP is generated, which carries small molecular oligomers and other impurities in the reaction process. When the NMP-containing gas enters the spray scraper condenser 1, the spray liquid enters the condenser from the spray liquid inlet 12 and fully contacts with the high-temperature gas. The temperature of the spray liquid is relatively low, and through heat exchange, the NMP gas is cooled to condense into a liquid state. In this process, small molecular oligomers and other impurities will gradually adhere to the inner wall of the condenser. The presence of the scraper device 13 is particularly important, which can timely remove the adhered impurities and avoid the accumulation of impurities on the inner wall of the condenser. Once the impurities accumulate too much, the heat transfer efficiency of the condenser will be affected, and even the internal passage of the condenser will be blocked, hindering the normal flow of gas and liquid. The scraper device 13 effectively solves this problem, ensuring the normal operation of the condenser and ensuring that the solvent recovery process can continue and stabilize.

[0029] The liquid seal tank 2 is connected to the bottom of the spray scraper condenser 1 through the atmospheric leg 14 at the top, and a filter screen 21 is arranged in the liquid seal tank 2. The liquid and impurity mixture treated by the spray scraper condenser 1 flows into the liquid seal tank 2 through the atmospheric leg 14, and the filter screen 21 can filter out impurities such as small molecular oligomers, so that the liquid flowing out of the liquid seal tank 2 is more pure.

[0030] Specifically, the mixture flowing out of the bottom of the spray scraper condenser 1 is the mixture of the cooled liquid and the impurities scraped off by the scraper. The atmospheric leg 14 serves as a channel connecting the two, and forms a liquid seal using liquid column pressure to prevent gas leakage and allow the liquid to flow smoothly into the liquid seal tank 2. The filter screen 21 in the liquid seal tank 2 plays a key filtering role, and its pore size design can intercept impurities such as small molecular oligomers. If these impurities are not filtered out, they may cause damage to the circulating pump 3, the heat exchanger 4 and other equipment, affecting the normal operation and service life of the equipment. Through the filtration of the filter screen 21, the impurity content of the liquid flowing out of the liquid seal tank 2 is greatly reduced, ensuring the purity of the subsequent circulating liquid and providing a guarantee for the stable operation of the entire solvent recovery system.

[0031] A circulating pump 3 is connected to the outlet of the liquid seal tank 2 and used to transport the filtered liquid in the liquid seal tank 2 to the heat exchanger 4. The circulating pump 3 acts as a “power source” in the entire solvent recovery system. The filtered liquid in the liquid seal tank 2 needs to be transported to the heat exchanger 4 for temperature adjustment to meet the temperature requirements of the spray liquid of the spray wiper condenser 1. The circulating pump 3 forms a negative pressure at its inlet through mechanical action, sucks the liquid in the liquid seal tank 2, and then uses the high-speed rotation of the impeller to apply energy to the liquid, so that the liquid obtains sufficient kinetic energy to overcome the pipeline resistance and be transported to the heat exchanger 4. The flow rate and head of the circulating pump 3 are selected according to the requirements of the system to ensure that the liquid can be stably transported to the specified position, maintain the circulation of the liquid in the system, and ensure the continuity of the solvent recovery process.

[0032] The heat exchanger 4 is connected to the outlet of the circulating pump 3 and the inlet 12 of the spray liquid of the spray wiper condenser 1. The liquid flowing out of the liquid seal tank 2 enters the heat exchanger 4 for cooling or heating under the action of the circulating pump 3, is adjusted to the appropriate temperature, and then returns to the spray wiper condenser 1 for circulation as spray liquid.

[0033] Specifically, the temperature of the liquid flowing out of the liquid seal tank 2 may not directly meet the temperature requirements of the spray liquid of the spray wiper condenser 1, so it needs to be adjusted by the heat exchanger 4. If the liquid temperature is too high, it will be cooled by heat exchange with the cooling medium (such as circulating cooling water) after entering the heat exchanger 4, and the heat will be transferred from the liquid to the cooling medium, reducing the temperature of the liquid; if the liquid temperature is too low, it may need to be heated (according to the actual process requirements). The plate heat exchanger 4 has the advantages of high heat transfer efficiency and compact structure due to its special structure, and can quickly and effectively adjust the temperature of the liquid. The liquid after temperature adjustment flows out of the outlet of the heat exchanger 4 and returns to the spray liquid inlet 12 of the spray wiper condenser 1 to participate in the cooling and absorption of NMP gas as spray liquid, forming a complete cycle, ensuring that the spray liquid is always within the appropriate temperature range, and improving the efficiency and quality of solvent recovery.

[0034] In one possible embodiment, the scraper device 13 includes a rotating shaft 131 and a spiral scraper 132, and the spiral scraper 132 is arranged along the inner wall of the spray wiper condenser 1 with a gap of 1-3 mm from the inner wall of the spray wiper condenser 1. This structure design enables the spiral scraper 132 to fully scrape off the impurities on the inner wall during rotation, while not causing excessive friction with the inner wall to damage the equipment.

[0035] Specifically, the rotating shaft 131 of the scraper device 13 rotates under the drive of the motor, and drives the spiral scraper 132 to rotate along the inner wall of the spray scraper condenser 1. The special shape and arrangement of the spiral scraper 132 along the inner wall enable it to cover most of the area of the inner wall of the condenser during rotation. The gap of 1-3 mm is carefully designed, which can ensure that the spiral scraper 132 is in full contact with the impurities on the inner wall and effectively removes the impurities, and also avoids excessive friction between the scraper and the inner wall. If the gap is too large, some impurities may not be removed; if the gap is too small, excessive friction between the scraper and the inner wall may occur, which not only accelerates the wear of the scraper, but also may damage the inner wall of the condenser, affecting the normal operation and service life of the equipment. Through such structural design, the scraper device 13 can work efficiently and stably, ensuring the normal operation of the condenser.

[0036] In a possible embodiment, the bottom of the liquid seal tank 2 is provided with an oligomer discharge port 22 connected with a control valve. The control valve can be used to periodically discharge the oligomers accumulated in the liquid seal tank 2, ensuring the normal operation of the liquid seal tank 2 and the filtering effect of the filter screen 21.

[0037] Specifically, during the solvent recovery process, although the filter screen 21 can filter out part of the impurities, a certain amount of oligomers will still accumulate in the liquid seal tank 2 over time. If these oligomers are not discharged in time, they will gradually accumulate at the bottom of the liquid seal tank 2, which may block the filter screen 21 and reduce its filtering effect, causing impurities to enter the subsequent circulation system. On the other hand, excessive accumulation of oligomers may affect the flow of liquid in the liquid seal tank 2 and the stability of the liquid level. By providing the oligomer discharge port 22 and the control valve, the operator can periodically open the control valve to discharge the accumulated oligomers from the liquid seal tank 2 according to the actual situation. This can keep the liquid seal tank 2 clean and ensure that the filter screen 21 is always in good working condition, maintaining the normal operation of the liquid seal tank 2 and ensuring the stable operation of the entire solvent recovery system.

[0038] In a possible embodiment, the heat exchanger 4 is a plate heat exchanger 4, and temperature sensors are arranged at the heat exchange medium inlet and outlet of the heat exchanger 4. The plate heat exchanger 4 has the advantages of high heat transfer efficiency and compact structure, and the temperature sensors can monitor the temperature of the heat exchange medium in real time, facilitating timely adjustment of the operating parameters of the heat exchanger 4 and ensuring the stability of the spray liquid temperature.

[0039] Specifically, the plate heat exchanger 4 is made of a series of metal plates with a corrugated shape, and fluid channels are formed between the plates. This special structure makes the heat transfer area of the plate heat exchanger 4 large, and the fluid forms a turbulent flow when flowing between the plates, greatly improving the heat transfer efficiency. At the same time, its structure is compact, occupies small space, and is suitable for installation and use in the solvent recovery system. Temperature sensors are installed at the inlet and outlet of the heat exchange medium, which can monitor the temperature of the heat exchange medium entering and flowing out of the heat exchanger 4 in real time. When the temperature sensor detects an abnormal temperature, such as a too high or too low spray liquid temperature, the control system can adjust the operating parameters of the heat exchanger 4 in a timely manner according to these data, such as adjusting the flow of the cooling medium (or heating medium), so as to ensure that the temperature of the spray liquid is stable within a suitable range. Stable spray liquid temperature is crucial to improving solvent recovery efficiency and ensuring system stability, which can ensure that the spray wiper condenser 1 is always in the best working condition.

[0040] In one possible embodiment, the spray liquid inlet 12 of the spray wiper condenser 1 is connected to the spray distributor 15. The spray distributor 15 can make the spray liquid more evenly distributed inside the condenser, increase the contact area between the spray liquid and the NMP gas, and improve the cooling and absorption effect.

[0041] Specifically, the spray distributor 15 is generally composed of a ring-shaped main pipe and a plurality of branch pipes, and the branch pipes are provided with spray heads. When the spray liquid enters the ring-shaped main pipe of the spray distributor 15 from the spray liquid inlet 12, it is divided into each branch pipe and then sprayed into the condenser through the spray head. This structure design can evenly disperse the spray liquid on the entire cross section of the condenser, avoiding the situation that the spray liquid is concentrated in a certain area. After increasing the contact area between the spray liquid and the NMP gas, the heat exchange and absorption process is more complete. More NMP gas molecules can be in contact with the spray liquid and be cooled and absorbed, thereby improving the recovery efficiency of NMP. At the same time, uniform spray distribution can also ensure that the temperature distribution inside the condenser is more uniform, reducing the phenomenon of local overheating or overcooling, which is beneficial to the stable operation of the condenser and the removal of impurities, further improving the overall performance of the solvent recovery system.

[0042] In one possible embodiment, the material of the spiral scraper 132 is polytetrafluoroethylene coated stainless steel with a thickness of 5-8 mm. The polytetrafluoroethylene coated stainless steel has good corrosion resistance and wear resistance, which can adapt to harsh working environment and prolong the service life of the spiral scraper 132.

[0043] Specifically, inside the spray blade condenser 1, the spiral scraper 132 needs to be in contact with the gas, liquid and adhered impurities containing corrosive substances for a long time, and the working environment is relatively harsh. The polytetrafluoroethylene coating has extremely low friction coefficient and good chemical stability, which can effectively prevent the surface of the scraper from being corroded and reduce the adhesion of impurities on the scraper. The stainless steel as the base material ensures the strength and rigidity of the scraper. The thickness of 5-8mm takes into account the strength and scraping effect of the scraper, which can ensure that the scraper will not deform due to insufficient strength during rotation, and also has enough mass to effectively remove impurities. The selection of such material and thickness enables the spiral scraper 132 to operate stably in a complex working environment for a long time, reduces the equipment maintenance and replacement costs caused by scraper damage, and improves the reliability and economy of the entire solvent recovery system.

[0044] In one possible embodiment, a liquid level sensor is arranged in the liquid seal tank 2, and the liquid level sensor is electrically connected with the frequency converter of the circulating pump 3. The liquid level sensor is used to control the flow of the circulating pump 3. The liquid level sensor can monitor the liquid level in the liquid seal tank 2 in real time, and control the flow of the circulating pump 3 according to the liquid level, so as to realize automatic control and stable operation of the system.

[0045] Specifically, the liquid level sensor can monitor the liquid level in the liquid seal tank 2 in real time, and convert the liquid level signal into an electrical signal and transmit it to the frequency converter of the circulating pump 3. When the liquid level in the liquid seal tank 2 rises, it means that the amount of liquid entering the liquid seal tank 2 is greater than the amount of liquid flowing out. At this time, the liquid level sensor will transmit the signal to the frequency converter, and the frequency converter will automatically increase the speed of the circulating pump 3, thereby increasing the flow of the circulating pump 3, so that more liquid can be transported to the heat exchanger 4 in time, and the balance of the liquid in the system is maintained. Conversely, when the liquid level decreases, the liquid level sensor transmits the signal to the frequency converter, and the frequency converter reduces the speed of the circulating pump 3 to reduce the flow of the circulating pump 3, so as to avoid the liquid in the liquid seal tank 2 being exhausted. Through the linkage control of the liquid level sensor and the frequency converter of the circulating pump 3, the automatic adjustment of the liquid flow in the system can be realized, so that the liquid level in the liquid seal tank 2 is always within a stable range, thereby ensuring the stable operation of the entire solvent recovery system, and improving the automation degree and operation efficiency of the system.

[0046] The operation process of the utility model is as follows:

[0047] First, the early preparation

[0048] Equipment inspection: Before the system starts, the operator needs to conduct a comprehensive inspection of each device. Check whether the scraper device 13 of the spray scraper condenser 1 is installed firmly, whether the rotating shaft 131 can rotate normally, and whether the gap between the spiral scraper 132 and the inner wall of the condenser is within 1-3mm; Check whether the filter screen 21 in the liquid seal tank 2 is intact, whether the control valve connected to the oligomer discharge port 22 can normally open and close; Check whether the inlet and outlet valves of the circulating pump 3 are in the correct position, and whether the motor is normal; Check whether the cooling medium inlet and outlet valves of the heat exchanger 4 are open, and whether the temperature sensor is working normally; Check whether the pipeline connection of the spray distributor 15 is tight, and whether the atomizing nozzle is blocked.

[0049] Parameter setting: According to the production process requirements, set the operating parameters of each device. For example, set the motor speed of the rotating shaft 131 of the scraper device 13 within the range of 6-12rpm through the frequency converter; Set the initial flow of the circulating pump 3 within the range of 80-120m³ / h; Set the inlet water temperature of the cooling medium of the heat exchanger 4 within the range of 20-25℃, and the outlet water temperature within the range of 30-35℃, to ensure that the spray liquid temperature entering the spray scraper condenser 1 is stable within the range of 25-30℃.

[0050] Second, system start

[0051] Start circulating pump 3: Start the circulating pump 3 to make the liquid in the liquid seal tank 2 start circulating. At this time, the circulating pump 3 will deliver the filtered liquid in the liquid seal tank 2 to the heat exchanger 4. During the start-up process, closely monitor the inlet and outlet pressures and flow of the circulating pump 3 to ensure that they are within the normal range.

[0052] Open the cooling medium: Open the inlet and outlet valves of the cooling medium of the heat exchanger 4 to make the cooling medium (such as circulating cooling water) start flowing, preparing for subsequent heat exchange. At the same time, observe the readings of the temperature sensor to ensure that the temperature of the cooling medium meets the set requirements.

[0053] Start the scraper device 13: Start the motor of the scraper device 13 to make the rotating shaft 131 drive the spiral scraper 132 to start rotating. Check the operation of the scraper device 13 to ensure that it rotates smoothly and the spiral scraper 132 can effectively remove impurities on the inner wall of the condenser.

[0054] Third, solvent recovery process

[0055] NMP gas enters: When the polyphenylene sulfide polymerization device is running normally, after the final reduction kettle reaction is completed, the mixture of polyphenylene sulfide finished product and NMP solvent enters the flash evaporation equipment for flash evaporation. The NMP gas flashed out has a temperature of about 180-200℃ and a pressure of about 0.1-0.2MPa, and enters the spray scraper condenser 1 through the NMP gas inlet 11.

[0056] Spray cooling and absorption: The NMP liquid cooled by the heat exchanger 4 has a temperature of about 25-30℃, and enters the spray distributor 15 from the spray liquid inlet 12. The spray distributor 15 uniformly sprays the spray liquid in the condenser, increasing the contact area between the spray liquid and the NMP gas. The NMP gas and the spray liquid are fully heat exchanged in the condenser, and the NMP gas is cooled into a liquid state. At the same time, at the heat exchange site, small molecule oligomers and other impurities are adhered to the inner wall of the condenser, and the rotating spiral scraper 132 timely scrapes off these impurities.

[0057] Liquid flows into the liquid seal tank 2: The condensed liquid and the scraped oligomers form a suspension, which is discharged into the liquid seal tank 2 through the atmospheric leg 14. The atmospheric leg 14 forms a liquid seal by using the liquid column pressure to prevent gas leakage and ensure the smooth flow of the liquid into the liquid seal tank 2.

[0058] Filtering impurities: The filter screen 21 in the liquid seal tank 2 filters the suspension and intercepts small molecule oligomers and other impurities. The filtered NMP liquid is more pure, which provides a guarantee for subsequent recycling.

[0059] Circulating cooling: The filtered NMP liquid enters the heat exchanger 4 again under the action of the circulating pump 3 for cooling. In the heat exchanger 4, the NMP is heat exchanged with the circulating cooling water, and after the temperature is reduced, it returns to the spray scraper condenser 1 as the spray liquid for recycling, which is repeated to realize the recycling of NMP.

[0060] Fourth, system monitoring and adjustment

[0061] Temperature monitoring and adjustment: The temperature sensor monitors the temperature of the NMP and the cooling medium at the inlet and outlet of the heat exchanger 4 in real time. If it is found that the temperature of the NMP liquid is too high or too low, the control system automatically adjusts the flow of the cooling medium of the heat exchanger 4 according to the data collected by the temperature sensor, so as to control the heat exchange effect of the heat exchanger 4 and ensure that the temperature of the spray liquid entering the spray scraper condenser 1 is stable within a suitable range.

[0062] Liquid level monitoring and adjustment: The liquid level sensor monitors the liquid level height in the liquid seal tank 2 in real time. When the liquid level rises, the liquid level sensor transmits a signal to the frequency converter of the circulating pump 3, and the frequency converter automatically increases the speed of the circulating pump 3 to increase the flow of the circulating pump 3, so that more liquid is transported to the heat exchanger 4; when the liquid level decreases, the frequency converter reduces the speed of the circulating pump 3 to reduce the flow of the circulating pump 3, so as to avoid the liquid in the liquid seal tank 2 being exhausted, and ensure the balance and stable operation of the liquid in the system.

[0063] Pressure and flow monitoring: regularly check the inlet and outlet pressure and flow of the circulating pump 3 to ensure that it is within the normal range. If the pressure or flow is found to be abnormal, check whether the pipeline is blocked, whether the valve is normally opened, etc. and take appropriate measures.

[0064] Fifth, oligomer discharge

[0065] Periodically open the control valve connected to the oligomer discharge outlet 22 at the bottom of the liquid seal tank 2 to discharge the oligomer accumulated in the liquid seal tank 2. The discharge period is determined according to the actual production situation, and generally a monthly check and discharge operation is performed to ensure the normal operation of the liquid seal tank 2 and the filtering effect of the filter screen 21.

[0066] Sixth, system shutdown

[0067] Close the NMP gas inlet 11: when the polyphenylene sulfide polymerization device stops running and no longer produces NMP gas, close the NMP gas inlet 11 valve to stop NMP gas from entering the spray blade condenser 1.

[0068] Stop the circulating pump 3 and the scraper device 13: stop the operation of the circulating pump 3 and the scraper device 13 in turn, and cut off the power supply.

[0069] Close the cooling medium: close the inlet and outlet valves of the cooling medium of the heat exchanger 4 to stop the flow of the cooling medium.

[0070] Equipment cleaning: clean the equipment in the system, such as cleaning the filter screen 21 in the liquid seal tank 2, checking the nozzles of the spray distributor 15, etc. to prepare for the next operation.

[0071] The technical features of the above-described embodiments can be combined in any way. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present disclosure.

[0072] The above-described embodiments only express several implementation manners of the present utility model, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the utility model patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present utility model, a number of modifications and improvements can be made, which are all within the protection scope of the present utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A solvent recovery system for a polyphenylene sulfide polymerization apparatus, characterized in that, The utility model relates to a kind of NMP condensing device, including: Spray blade condenser (1), the spray blade condenser (1) is equipped with NMP gas inlet (11) spray liquid inlet (12), the inside of the spray blade condenser (1) is provided with doctor device (13); Liquid seal groove (2), the top of the liquid seal groove (2) is communicated with the bottom of the spray blade condenser (1) by atmospheric leg (14), the liquid seal groove (2) is equipped with filter screen (21); Circulating pump (3), the inlet of the circulating pump (3) is connected with the outlet of the liquid seal groove (2); Heat exchanger (4), the inlet of the heat exchanger (4) is connected with the outlet of the circulating pump (3), and the outlet of the heat exchanger (4) is connected with the spray liquid inlet (12) of the spray blade condenser (1).

2. The solvent recovery system for a polyphenylene sulfide polymerization apparatus according to claim 1, characterized by The doctor device (13) includes rotating shaft (131) and spiral doctor (132), the spiral doctor (132) is arranged along the inner wall of the spray blade condenser (1), and the gap between the spiral doctor (132) and the inner wall of the spray blade condenser (1) is 1-3mm.

3. The solvent recovery system for a polyphenylene sulfide polymerization apparatus according to claim 1, characterized by The bottom of the liquid seal groove (2) is equipped with oligomer discharge port (22), and the control valve is connected with the oligomer discharge port (22).

4. The solvent recovery system for a polyphenylene sulfide polymerization apparatus according to claim 1, characterized by The heat exchanger (4) is plate heat exchanger, and temperature sensor is equipped at the inlet and outlet of the heat exchange medium of the heat exchanger (4).

5. The solvent recovery system for a polyphenylene sulfide polymerization apparatus according to claim 1, characterized by The spray liquid inlet (12) of the spray blade condenser (1) is connected with spray distributor (15).

6. The solvent recovery system for a polyphenylene sulfide polymerization apparatus according to claim 2, characterized by The material of the spiral doctor (132) is polytetrafluoroethylene coating stainless steel, and the thickness is 5-8mm.

7. The solvent recovery system of claim 1, wherein The liquid seal groove (2) is equipped with liquid level sensor, and the liquid level sensor is electrically connected with the frequency converter of the circulating pump (3), and the liquid level sensor is used to control the flow of the circulating pump (3).

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