A purification method for high-purity fluorinated carbonate-based solvents

Abstract

This invention relates to the field of fluorination process technology, and particularly to a method for purifying high-purity fluorinated carbonate-based solvents. The steps are as follows: S1, crude gas containing fluorinated carbonate-based solvent is introduced into a purification chamber and liquefied using a liquefaction separation module; S2, the liquid obtained in S1 is separated and transported into a crystallization tank, where the liquid is cooled to a critical crystallization state. Simultaneously, a rotating crystallizer assembly rotates within the crystallization tank, and the liquid crystallizes on the surface of the rotating crystallizer assembly. The crystals are then continuously collected above the crystallization tank using a collection component; S3, the crystals collected in S2 are washed and filtered to obtain the high-purity fluorinated carbonate-based solvent. The purification method for high-purity fluorinated carbonate-based solvents provided by this invention uses a liquefaction module to liquefy the crude gas first, and then uses a rotating crystallization module to continuously collect the liquefied liquid. This method can efficiently and simply prepare high-purity fluorinated carbonate-based solvents and has good industrial value.

Description

Technical Field

[0001] This invention relates to the field of fluorination technology, and in particular to a method for purifying high-purity fluorinated carbonate-based solvents. Background Technology

[0002] Fluorinated carbonates, such as fluoroethylene carbonate and fluoropropylene carbonate, are key additives in lithium-ion battery electrolytes. Fluorinated carbonate-based solvents play an irreplaceable role in high-energy-density batteries due to their excellent electrochemical stability and film-forming properties. With the rapid development of new energy vehicles and energy storage industries, the demand for high-purity, high-performance fluorocarbonate solvents has exploded, and traditional production processes can no longer meet the market's dual demands for product quality and production efficiency.

[0003] Currently, the industrial purification of fluorocarbonate-based solvents mainly employs traditional methods such as vacuum distillation, recrystallization, and melt crystallization. While vacuum distillation is relatively simple to operate, it is difficult to effectively separate impurities with similar boiling points, and high-temperature conditions can easily lead to the decomposition of heat-sensitive components, affecting product purity and yield.

[0004] Recrystallization typically requires the use of a mixed solvent such as toluene and n-hexane, and is carried out at low temperatures of -30°C to 0°C. This not only makes the process complex but also makes solvent recovery difficult, which can easily lead to environmental pollution and product loss.

[0005] Melt crystallization is a highly efficient chemical separation technology widely used for the purification of high-purity substances such as chemical intermediates, pharmaceutical intermediates, and biochemical products. This technology is mainly divided into two categories: suspension crystallization and layer crystallization. It is suitable for organic chemicals with melting points between -10℃ and 200℃, especially substances in the 15℃ to 150℃ range. Compared with traditional methods such as distillation and extraction, melt crystallization can operate under normal pressure and low temperature conditions, consuming only 10% to 30% of the energy of distillation, significantly reducing costs. The melting points of most fluorocarbonate-based solvents fall within the applicable range of melt crystallization, making it an efficient purification process for them.

[0006] However, existing melt crystallization equipment generally suffers from problems such as low crystallization efficiency, difficulty in crystal collection, and high energy consumption. Furthermore, existing melt crystallization equipment is mainly intermittent, resulting in low operating efficiency and an inability to meet the demands of continuous and automated production.

[0007] Therefore, there is an urgent need to develop an efficient and stable purification method for high-purity fluorinated carbonate-based solvents to meet the requirements for continuous production of high-purity fluorinated carbonate-based solvents. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a purification method for high-purity fluorinated carbonate-based solvents, thereby solving the problems of low purification efficiency and difficulty in adapting to continuous production in existing fluorinated carbonate-based solvent purification processes.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a purification method for high-purity fluorinated carbonate-based solvents, comprising the following steps:

[0010] S1. Fluorocarbonate-based solvent crude gas is introduced into the purification cavity of the purification body. The crude gas entering the purification cavity is liquefied by the liquefaction separation module set at the top of the purification cavity, and the liquefied mixture is separated in the hydrocyclone separator to obtain the liquid to be purified.

[0011] S2. The liquid obtained in S1 is transported into the crystallization pool of the rotating crystallization module. The crystallization pool cools the liquid and brings it into the critical state of crystallization. At the same time, the rotating crystal plate group rotates in the crystallization pool, and the liquid crystallizes on the surface of the crystallization plate group. Then, the crystals are continuously collected above the crystallization pool by the collection component.

[0012] S3. The collecting component uses hot air to detach and collect the crystals on the surface of the crystallization plate. The collected crystals are then washed and filtered to obtain a high-purity fluorinated carbonate-based solvent.

[0013] In step S2, the crystallization pool is located below the purification cavity to receive the liquid separated by the liquefaction separation module. The rotating crystal plate assembly includes a crystallization driving component, a crystallization plate, and a heat exchange component. The center of the crystallization plate is connected to the crystallization driving component. A heat exchange cavity is provided inside the crystallization plate. The heat exchange component is located on both sides of the crystallization plate and communicates with the heat exchange cavity. The heat exchange component is used to input the heat exchange medium into the heat exchange cavity and output it from the heat exchange cavity. The crystallization plate extends into the crystallization pool. The crystallization plate rotates under the drive of the crystallization driving component. The liquid in the crystallization pool condenses and crystallizes on the surface of the crystallization plate. The collection component is located on both sides of the crystallization plate and above the liquid surface of the crystallization pool. It is used to melt and collect the crystals on the surface of the crystallization plate that rotates to the top of the crystallization pool by hot air.

[0014] Preferably, in S3, the collecting component completely melts the crystal, directly collecting and transporting the liquid formed by the melting of the crystal without the need for washing and filtration.

[0015] In one embodiment, S31, the collecting component uses hot air to completely melt the crystals on the surface of the crystallizing plate;

[0016] S32. The molten crystal obtained in S31 is transported into the recrystallization zone, where it is crystallized by the rotating crystal plate group. The crystal is then collected by the collection component in the recrystallization zone and output.

[0017] In one embodiment, a zone partition plate is provided in the crystallization pool. The zone partition plate is located on the side of the crystallization pool away from the liquefaction separation module. The zone partition plate divides the crystallization pool into a recrystallization zone. A rotating crystal plate assembly is correspondingly provided in the recrystallization zone. The crystals collected by the collection component in the crystallization pool are heated and melted and then transported to the recrystallization zone.

[0018] In one embodiment, in step S2, the temperature of the crystallization pool is higher than the melting point of the fluorocarbonate-based solvent to be purified, and the temperature of the heat exchange medium in the heat exchange chamber is lower than the melting point of the fluorocarbonate-based solvent to be purified.

[0019] In one embodiment, in step S1, the liquefaction separation module includes a cooling chamber and a cyclone separator. The cyclone separator is disposed in the cooling chamber, and an input pipe is provided at the bottom of the cooling chamber. The input pipe spirals upward around the cyclone separator and is tangentially connected to the cyclone separator. The cooling chamber is used to exchange heat with the crude gas in the input pipe, so that the crude gas is liquefied and enters the cyclone separator for gas-liquid separation.

[0020] In one embodiment, the crystallization plate includes a concave region, a convex region, and a mounting region sequentially from the outer ring to the inner ring. The thickness of the concave region gradually decreases, while the thickness of the convex region first increases and then decreases. The cross-section of the convex region is conical. A driving hole is provided at the center of the mounting region, and the crystallization driving assembly is connected to the crystallization plate through the driving hole.

[0021] In one embodiment, the collecting assembly includes a collecting arc groove, a collecting pipeline, a supporting arc plate, and a purging pipeline. The collecting arc groove is disposed on both sides of the crystallization plate and located above the crystallization driving assembly. The supporting arc plate is disposed below the collecting arc groove and has a heating gas passage inside. The collecting pipeline is connected to the collecting arc groove and is used to transport the molten liquid in the collecting arc groove. The purging pipeline is disposed on both sides above the crystallization plate and is used to blow hot air into the concave area of ​​the crystallization plate.

[0022] In one embodiment, the supporting arc plate is provided with an upward nozzle on the side near the crystallizing plate. The upward nozzle is used to blow air upward and make the air flow outward along the mounting area. The supporting arc plate is provided with a purging nozzle on the side away from the crystallizing plate. The purging nozzle is used to blow downward airflow onto the crystallizing plate below the displaced supporting arc plate.

[0023] In one embodiment, the crystallization driving assembly includes a drive motor, a magnetic coupler, and a drive rod. The drive motor is located on the outside of the purification body, and the output end of the drive motor is driven to the drive rod through the magnetic coupler. The drive rod is driven to the rotating crystal plate assembly.

[0024] In one embodiment, the heat exchange assembly includes two sealing ring covers, which are respectively embedded in the mounting areas on both sides of the crystallizing plate. A drive rod passes through the sealing ring cover, and the sealing ring cover is rotatably connected to the drive rod and the crystallizing plate. The side of the sealing ring cover closer to the mounting area has through holes spaced apart, and the side of the sealing ring cover away from the mounting area has an inflow pipe or an outflow pipe. The mounting area has a medium passage corresponding to the through holes that communicates with the heat exchange cavity. The sealing ring cover has a medium ring cavity inside. The heat exchange medium enters the medium ring cavity through the inflow pipe and then enters the heat exchange cavity, and flows out of the heat exchange cavity through the outflow pipe of the other sealing ring cover.

[0025] The beneficial effects of this invention are as follows: Industrially, the purification of fluorocarbonate-based solvents mainly employs traditional methods such as vacuum distillation, recrystallization, and melt crystallization. Melt crystallization offers significant advantages over vacuum distillation and recrystallization in terms of lower cost and higher purification efficiency. However, existing melt crystallization equipment mostly employs static crystallization, where crystal growth on a fixed surface leads to low heat and mass transfer efficiency. Boundary layers easily form at the crystallization interface, hindering material diffusion. Furthermore, it lacks integrated liquefaction separation and crystal collection functions, requiring additional equipment and increasing system complexity and contamination risks. Regarding crystal collection, reliance on manual scraping or mechanical peeling is not only cumbersome and results in significant crystal loss, but the mechanical contact of the scraper can also introduce metal ions, affecting product purity and leading to large batch-to-batch quality fluctuations. Moreover, existing melt crystallization equipment is mostly intermittently operated, unable to achieve continuous production, with low automation requiring frequent manual intervention, making it difficult to meet the production demands of high-purity fluorocarbonate-based solvents.

[0026] Therefore, the purification method employed in this invention utilizes a rotating crystallization module. A crystallization plate extends into the crystallization pool, providing a crystallization interface that allows crystals to form on the extended portion of the plate. A crystallization drive component continuously rotates the crystallization plate, constantly updating the crystallization interface. This ensures the liquid in the crystallization pool continuously contacts new crystallization interfaces, resulting in the continuous generation of a uniform and stable crystal layer. Furthermore, the continuous rotation of the crystallization plate disturbs the liquid in the crystallization pool, effectively avoiding boundary layer effects caused by crystal growth and significantly improving the crystallization rate. Simultaneously, during the rotation of the crystallization plate, the continuously generated crystal layer is rotated to the top of the crystallization pool. A collection component melts the crystal layer with hot air and collects the melt. This reheating and melting of the crystals eliminates mechanical contact during collection, preventing damage and contamination from mechanical scraping and ensuring continuous and automated crystal collection. The hot air melting process also restores the collected crystals to a liquid state, enabling automated transport and ensuring the stability of the entire continuous production process.

[0027] Furthermore, in the liquefaction separation module employed in this invention, the input pipe spirals upwards around the cyclone separator within the cooling chamber. This allows the cooling chamber to simultaneously cool both the input pipe and the cyclone separator, ensuring the complete liquefaction of the fluorocarbonate-based solvent in the crude gas. Simultaneously, the gas-liquid mixture inside the spirally rising input pipe enters the cyclone separator tangentially, where centrifugal force effectively separates the gas and liquid phases. Meanwhile, the cooling medium within the cooling chamber maintains a stable overall temperature within the cyclone separator, allowing the residual fluorocarbonate-based solvent gas in the crude gas to continue liquefying during its flow within the cyclone separator, thus ensuring product yield.

[0028] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects of the invention and other beneficial effects may be realized and obtained by means of the structures and / or components pointed out in the description and claims. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0030] Figure 2 This is a perspective view of an embodiment of the present invention;

[0031] Figure 3 for Figure 2 Top view;

[0032] Figure 4 for Figure 3 Cross-sectional view at point AA;

[0033] Figure 5 for Figure 4 A magnified view of a section at point C;

[0034] Figure 6 for Figure 2 The main view;

[0035] Figure 7 for Figure 6 Cross-sectional view at point BB;

[0036] Figure 8 for Figure 7 A magnified view of a section at point D;

[0037] Figure 9 This is a schematic diagram of the internal structure of an embodiment of the present invention;

[0038] Figure 10 This is a schematic diagram of the internal structure from another angle of an embodiment of the present invention;

[0039] Figure 11 for Figure 9A magnified view of a section at point E in the middle;

[0040] Figure 12 for Figure 10 A magnified view of a section at point F.

[0041] Label Explanation:

[0042] 1. Purification body; 11. Purification cavity; 2. Liquefaction separation module; 21. Cooling chamber; 22. Cyclone separator; 23. Input pipe; 3. Rotary crystallization module; 31. Crystallization pool; 311. Zone partition plate; 32. Rotary crystal plate assembly; 321. Crystallization drive assembly; 3211. Drive motor; 3212. Magnetic coupler; 3213. Drive rod; 322. Crystallization plate; 3221. Heat exchange chamber; 3222. Concave area; 3223. Convex area 3224. Installation area; 3225. Medium passage; 3226. Intermediate plate; 323. Heat exchange assembly; 3231. Sealing ring cover; 3232. Inlet pipe; 3233. Outlet pipe; 3234. Medium ring cavity; 33. Collection assembly; 331. Collection arc groove; 332. Collection pipeline; 333. Supporting arc plate; 3331. Heating gas passage; 3332. Rising nozzle; 3333. Purge nozzle; 334. Purge pipeline; 34. Fixed bracket. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0045] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0046] Please refer to Figures 1 to 12A purification method for high-purity fluorinated carbonate-based solvents, comprising the following steps:

[0047] S1. Fluorocarbonate-based solvent crude gas is introduced into the purification cavity 11 of the purification body 1. The crude gas entering the purification cavity 11 is liquefied by the liquefaction separation module 2 set at the top of the purification cavity 11. The liquefied mixture is then separated in the hydrocyclone separator 22 to obtain the liquid to be purified.

[0048] S2. The liquid obtained in S1 is transported into the crystallization pool 31 of the rotating crystallization module 3. The crystallization pool 31 cools the liquid and brings it into the critical state of crystallization. At the same time, the rotating crystal plate group 32 rotates in the crystallization pool 31. The liquid crystallizes on the surface of the crystallization plate 322 of the rotating crystal plate group 32. Then, the crystallization is continuously collected above the crystallization pool 31 by the collection component 33.

[0049] S3. The collecting component 33 uses hot air to detach and collect the crystals on the surface of the crystallizing plate 322. The collected crystals are then washed and filtered to obtain a high-purity fluorinated carbonate-based solvent.

[0050] The rotating crystallization module 3 includes a crystallization pool 31, a rotating crystal plate assembly 32, and a collection component 33. The crystallization pool 31 is located below the purification cavity 11 and is used to receive the liquid separated by the liquefaction separation module 2. The rotating crystal plate assembly 32 includes a crystallization driving component 321, a crystallization plate 322, and a heat exchange component 323. The center of the crystallization plate 322 is connected to the crystallization driving component 321. A heat exchange chamber 3221 is provided inside the crystallization plate 322. The heat exchange components 323 are located on both sides of the crystallization plate 322 and are connected to the heat exchange chamber 322. 1. The heat exchange component 323 is used to input the heat exchange medium into the heat exchange chamber 3221 and output it from the heat exchange chamber 3221; the crystallizing plate 322 extends into the crystallization pool 31 and rotates under the drive of the crystallization driving component 321. The liquid in the crystallization pool 31 condenses and crystallizes on the surface of the crystallizing plate 322. The collecting component 33 is located on both sides of the crystallizing plate 322 and above the liquid surface of the crystallization pool 31. It is used to melt and collect the crystals on the surface of the crystallizing plate 322 that rotates to the top of the crystallization pool 31 by hot air.

[0051] Specifically, the bottom of the cyclone separator 22 is connected to the crystallization tank 31 through a transition tank, and a one-way valve is provided between the transition tank and the crystallization tank 31.

[0052] Preferably, in step S3, the collecting component 33 completely melts the crystals, directly collecting and transporting the liquid formed by the melting of the crystals without the need for washing and filtration, thereby improving purification efficiency.

[0053] Preferably, the crystallization tank 31 is equipped with a temperature control device and an insulation layer, so that the temperature of the liquid in the crystallization tank 31 is slightly higher than the melting point of the fluorocarbonate-based solvent to be purified, thereby keeping the fluorocarbonate-based solvent to be purified in a critical state of crystallization, and the temperature of the crystallization plate 322 is lower than the melting point of the fluorocarbonate-based solvent to be purified. More preferably, the crystallization tank 31 is 1-5°C higher than the melting point of the fluorocarbonate-based solvent to be purified, and the melting point of the fluorocarbonate-based solvent to be purified is 5-20°C.

[0054] Preferably, the rotational speed of the crystallizing plate 322 is in the range of 1 to 60 rpm. More preferably, the rotational speed of the crystallizing plate 322 is in the range of 5 to 25 rpm.

[0055] In this embodiment, step S3 further includes:

[0056] S31, the collecting component 33 uses hot air to completely melt the crystals on the surface of the crystallizing plate 322;

[0057] S32. The molten crystal obtained in S31 is transported into the recrystallization zone, crystallized by the rotating crystal plate group 32 in the recrystallization zone, and then collected and output by the collection component 33 in the recrystallization zone.

[0058] In this embodiment, a partition plate 311 is provided within the crystallization tank 31. The partition plate 311 is located on the side of the crystallization tank 31 away from the liquefaction separation module 2. The partition plate 311 divides the crystallization tank 31 into a recrystallization zone. A rotating crystal plate assembly 32 is correspondingly provided in the recrystallization zone. The crystals collected by the collection component 33 in the crystallization tank 31 are heated and melted, then transported to the recrystallization zone, where they are collected and output by the collection component 33. By setting the partition plate 311, the crystallization tank 31 can be divided into zones, and the collected product can be transported into different zones by the collection component 33 for multi-stage crystallization, thereby improving the purity of the product.

[0059] In this embodiment, the surface of the crystallization plate 322 is provided with a separating protrusion (not shown in the figure), which extends from the edge of the crystallization plate 322 to the boundary between the concave region 3222 and the convex region 3223. The separating protrusion can restrict the flow direction of the molten crystals and enhance the disturbance to the surrounding liquid in the crystallization pool 31, effectively improving the crystallization rate and purification efficiency.

[0060] In this embodiment, in step S2, the temperature of the crystallization pool 31 is higher than the melting point of the fluorocarbonate-based solvent to be purified, and the temperature of the heat exchange medium in the heat exchange chamber 3221 is lower than the melting point of the fluorocarbonate-based solvent to be purified.

[0061] In this embodiment, in step S1, the liquefaction separation module 2 includes a cooling chamber 21 and a cyclone separator 22. The cyclone separator 22 is disposed in the cooling chamber 21. An input pipe 23 is provided at the bottom of the cooling chamber 21. The input pipe 23 spirals around the cyclone separator 22 and is tangentially connected to the cyclone separator 22. The cooling chamber 21 is used to exchange heat with the crude gas in the input pipe 23, so that the crude gas is liquefied and enters the cyclone separator 22 for gas-liquid separation.

[0062] If the crystallization plate 322 were entirely planar, not only would the crystallization area be limited, but when the crystals rotate to the top to melt, they would flow tightly against the surface of the crystallization plate 322, making it difficult for them to detach via airflow. Therefore, the crystallization plate 322 includes, from the outer ring to the inner ring, a concave region 3222, a convex region 3223, and a mounting region 3224. The thickness of the concave region 3222 gradually decreases, while the thickness of the convex region 3223 first increases and then decreases, with a conical cross-section. A driving hole is provided at the center of the mounting region 3224, through which the crystallization driving assembly 321 is connected to the crystallization plate 322. That is, the thickness of the crystallization plate 322 gradually decreases from the outer periphery to the center, and then a protruding conical ring is provided at the outer edge of the safety zone. The molten liquid detaches from the surface of the crystallization plate 322 when it flows to the thickest point of the conical ring.

[0063] If the collecting component 33 simply blows hot air onto the surface of the crystallization disk, even if the crystallization plate 322 is partitioned, it is difficult to control the dripping point of the molten crystals, which is not conducive to product collection and results in low final purification efficiency. In this embodiment, the collecting component 33 includes a collecting arc groove 331, a collecting pipe 332, a supporting arc plate 333, and a blowing pipe 334. The collecting arc groove 331 is located on both sides of the crystallization plate 322 and above the crystallization driving component 321. The supporting arc plate 333 is located below the collecting arc groove 331 and has a heating gas passage 3331 inside. The collecting pipe 332 is connected to the collecting arc groove 331 and is used to transport the molten liquid inside the collecting arc groove 331. The blowing pipe 334 is located on both sides above the crystallization plate 322 and is used to blow hot air into the concave area 3222 of the crystallization plate 322. Hot air is blown upwards from the purging pipe 334 onto the crystallization plate 322, melting the crystals while controlling the flow direction of the molten crystals. This causes the product to flow towards the outward convex area 3223 and be guided to the collecting arc groove 331. Simultaneously, a heating gas passage 3331 is provided within the supporting arc plate 333, ensuring that the temperature of the collecting arc groove 331 on the supporting arc plate 333 is higher than the melting point of the fluorocarbonate-based solvent to be purified. This keeps the product in the collecting arc groove 331 in a liquid state, allowing it to be transported through the collecting pipe 332.

[0064] Preferably, the purge pipe 334 located on both sides of the crystallization plate 322 is arc-shaped. This arrangement can increase the airflow coverage area and control the airflow direction so that most of the molten crystals flow towards the center, ensuring collection efficiency and preventing the molten crystals from flowing back into the crystallization pool 31.

[0065] Preferably, the gas used for purging in the purging pipeline 334 and the heating gas pipeline 3331 is an inert gas. After purging, the inert gas is recovered and heated through a circulation pipe set at the top of the purification cavity 11 and recycled.

[0066] Preferably, the portion of the collecting arc groove 331 near the mounting area 3224 can extend into the mounting area 3224 without mechanically contacting the crystallizing plate 322. This further expands the coverage area of ​​the collecting arc groove 331, thereby collecting more products and improving overall working efficiency.

[0067] If only one side is blown, it is still impossible to ensure that the molten crystal completely falls off from the outer convex area 3223, and the temperature of the hot air decreases after flowing along the crystallizing plate 322 to the center, which is not conducive to the melting of the crystal in the central area. Therefore, in this embodiment, the supporting arc plate 333 is provided with an upward nozzle 3332 on the side close to the crystallizing plate 322. The upward nozzle 3332 is used to blow the airflow upward and make the airflow flow along the mounting area 3224 to the outer convex area 3223; the supporting arc plate 333 is provided with a blowing nozzle 3333 on the side away from the crystallizing plate 322. The blowing nozzle 3333 is used to blow the airflow downward to the crystallizing plate 322 below the displaced supporting arc plate 333. Hot air is blown from the rising nozzle 3332 to the mounting area 3224, and then flows to the outward convex area 3223. At this time, the hot air blown by the purging pipe 334 flows along the concave area 3222 of the crystallizing plate 322 to the outward convex area 3223. The molten crystals flowing to the outward convex area 3223 are purged into the collecting arc groove 331 by the hot air from the inside and outside. Meanwhile, the purging nozzle 3333 blows airflow onto the surface of the crystallizing plate 322 located below the drive rod 3213. When the crystallizing plate 322 rotates away from the liquid surface, it can blow the uncrystallized liquid back into the crystallization pool 31, thereby preventing liquid from mixing into the molten crystals and ultimately improving the yield.

[0068] To prevent product leakage and external contamination, in this embodiment, the crystallization driving assembly 321 includes a drive motor 3211, a magnetic coupler 3212, and a drive rod 3213. The drive motor 3211 is located on the outside of the purification body 1. The output end of the drive motor 3211 is driven and connected to the drive rod 3213 via the magnetic coupler 3212. The drive rod 3213 is driven and connected to the rotating crystal plate assembly 32. By using the magnetic coupler 3212, the drive rod 3213 does not need to penetrate the wall of the purification body 1, significantly reducing the sealing requirements of the device, thereby improving safety and significantly reducing costs.

[0069] The crystallization plate 322 has a heat exchange chamber 3221 inside. By introducing a heat exchange medium, the temperature of the crystallization plate 322 is lower than the melting point of the fluorocarbonate-based solvent to be purified, thereby cooling the liquid in contact with the crystallization plate 322 and causing it to crystallize on the surface of the crystallization plate 322. However, since the crystals rotating upwards need to be melted by hot air, if the entire crystallization plate 322 is filled with heat exchange medium, it can easily affect the remelting of the crystals, resulting in incomplete melting of the crystals. Therefore, in this embodiment, the heat exchange assembly 323 includes two sealing ring covers 3231, which are respectively embedded in the mounting areas 3224 on both sides of the crystallizing plate 322. The drive rod 3213 passes through the sealing ring cover 3231, and the sealing ring cover 3231 is rotatably connected to the drive rod 3213 and the crystallizing plate 322. The side of the sealing ring cover 3231 near the mounting area 3224 has through holes distributed at intervals, and the side of the sealing ring cover 3231 away from the mounting area 3224 is provided with an inflow pipe 3232 or an outflow pipe 3233. The mounting area 3224 is provided with a medium passage 3225 corresponding to the through hole, which communicates with the heat exchange cavity 3221. The sealing ring cover 3231 has a medium ring cavity 3234 inside. The heat exchange medium enters the medium ring cavity 3234 through the inflow pipe 3232 and then enters the heat exchange cavity 3221, and flows out of the heat exchange cavity 3221 through the outflow pipe 3233 of the sealing ring cover 3231 on the other side. By using sealing ring covers 3231 on both sides of the crystallizing plate 322, heat exchange medium is continuously input and output during the rotation of the crystallizing plate 322, so that the heat exchange medium exists only in the lower half of the crystallizing plate 322, thus not affecting the melting and detachment of the crystals above. This ensures that the temperature of the part of the crystallizing plate 322 that extends into the crystallizing pool 31 can exchange heat with the liquid in the crystallizing pool 31 without affecting the rotation of the crystallizing plate 322, thereby crystallizing on the crystallizing plate 322.

[0070] If the heat exchange cavity 3221 is entirely a continuous passage, dead zones will appear in the flow of the heat exchange medium, preventing the bottom heat exchange medium from being refreshed and affecting the crystallization effect. Therefore, in this embodiment, an intermediate plate 3226 is provided inside the heat exchange cavity 3221. The diameter of the intermediate plate 3226 is smaller than the diameter of the crystallization plate 322. This arrangement divides the heat exchange cavity 3221 in each crystallization plate 322 into left and right parts. The heat exchange medium enters the other part through the edge channel, thereby allowing the heat exchange medium to flow along a preset path and preventing unexchanged heat exchange medium from flowing directly out of the heat exchange cavity 3221.

[0071] Since the sealing ring cover 3231 needs to remain stationary, it needs to be fixed. In this embodiment, the rotating crystallization module 3 also includes a fixing bracket 34, the two ends of which are connected to the inner wall of the purification cavity 11, and the fixing bracket 34 is connected to the sealing ring cover 3231 through a support rod.

[0072] Preferably, bearings are provided on both the inner and outer sides of the sealing ring cover 3231 to prevent the sealing ring cover 3231 from affecting the rotation of the crystallizing plate 322 and the drive rod 3213.

[0073] Specifically, the cooling chamber 21 and the cyclone separator 22 can be made of 316L stainless steel or Hastelloy C-276 alloy to ensure good corrosion resistance and sealing performance during cryogenic liquefaction; the inlet pipe 23 can be made of duplex stainless steel (model 2205) or Hastelloy C-22 alloy to ensure the long-term stability of the spiral rising structure in corrosive gas environments. The crystallization tank 31: adopts a 316L stainless steel matrix + PTFE lining composite structure, or is entirely made of Hastelloy B-3 alloy to ensure corrosion resistance during long-term contact with liquid fluorocarbonate;

[0074] The crystallization plate 322 is made of Hastelloy C-276, balancing rotational strength, thermal conductivity, and corrosion resistance. The heat exchange assembly 323 uses PEEK engineering plastic with a 316L stainless steel frame, and the piping uses Inconel 625 nickel-based alloy to ensure rotary sealing and heat exchange efficiency. The collection assembly 33 uses 316L stainless steel with an electrolytically polished inner surface, and the seals use perfluoroelastomer rubber to ensure high-purity product collection. The fixed bracket 34 and the zone partition plate 311 use a structure of 316L stainless steel covered with PVDF material to ensure structural strength and chemical inertness. Those skilled in the art can select appropriate materials as needed, ensuring structural strength and corrosion resistance, without specific limitations.

[0075] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0076] Although this document frequently uses terms such as purification body and purification cavity, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any kind of additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present) in the specification and claims of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for purifying a high purity fluorocarbonate-based solvent, characterized by, The steps are as follows: S1, crude gas of fluorinated carbonate-based solvent is introduced into a purification cavity (11) of a purification main body (1), the crude gas entering the purification cavity is liquefied by a liquefaction separation module (2) arranged at the top of the purification cavity (11), and the liquefied mixture is separated in a cyclone separator (22) to obtain a liquid to be purified; S2, the liquid obtained in S1 is transported into a crystallization pool (31) of a rotary crystallization module (3), the crystallization pool (31) cools the liquid to a crystallization critical state, and a rotary crystal plate group (32) rotates in the crystallization pool (31), the liquid crystallizes on the surface of a crystallization plate (322) of the rotary crystal plate group (32), and then the crystallization is continuously collected by a collection assembly (33) above the crystallization pool (31); S3, the collection assembly (33) separates the crystallization on the surface of the crystallization plate (322) by hot air and collects it, and the collected crystal is washed and filtered to obtain high-purity fluorinated carbonate-based solvent; In step S2, the crystallization pool (31) is arranged below the purification cavity (11) and is used to receive the liquid separated by the liquefaction separation module (2); the rotary crystal plate group (32) includes a crystallization driving assembly (321), a crystallization plate (322), and a heat exchange assembly (323), the center of the crystallization plate (322) is connected with the crystallization driving assembly (321), the crystallization plate (322) is provided with a heat exchange cavity (3221) therein, the heat exchange assembly (323) is arranged on both sides of the crystallization plate (322) and communicates with the heat exchange cavity (3221), and the heat exchange assembly (323) is used to input a heat exchange medium into the heat exchange cavity (3221) and output the heat exchange medium from the heat exchange cavity (3221); the crystallization plate (322) partially extends into the crystallization pool (31), the crystallization plate (322) rotates under the drive of the crystallization driving assembly (321), the liquid in the crystallization pool (31) condenses and crystallizes on the surface of the crystallization plate (322), and the collection assembly (33) is arranged on both sides of the crystallization plate (322) and above the liquid surface of the crystallization pool (31) and is used to melt the crystal on the surface of the crystallization plate (322) rotating above the crystallization pool (31) by hot air and collect the crystal; The crystallization plate (322) includes an inner concave area (3222), an outer convex area (3223), and a mounting area (3224) from the outer ring to the inner ring in sequence, the thickness of the inner concave area (3222) gradually decreases, the thickness of the outer convex area (3223) first increases and then decreases, and the cross section of the outer convex area (3223) is conical; the center of the mounting area (3224) is provided with a driving hole, and the crystallization driving assembly (321) is connected with the crystallization plate (322) through the driving hole. The crystallization driving assembly (321) comprises a driving motor (3211), a magnetic coupler (3212) and a driving rod (3213), the driving motor (3211) is arranged outside the purification main body (1), the output end of the driving motor (3211) is drivingly connected with the driving rod (3213) through the magnetic coupler (3212), and the driving rod (3213) is drivingly connected with the rotating crystal plate group (32). The heat exchange assembly (323) comprises two sealing ring covers (3231), the sealing ring covers (3231) are respectively embedded in the mounting areas (3224) on the two sides of the crystallization plate (322), the driving rod (3213) penetrates through the sealing ring covers (3231), the sealing ring covers (3231) are rotatably connected with the driving rod (3213) and the crystallization plate (322), a plurality of through holes are distributed on the side of the sealing ring covers (3231) close to the mounting areas (3224) at intervals, the side of the sealing ring covers (3231) away from the mounting areas (3224) is provided with an inflow pipe (3232) or an outflow pipe (3233), the mounting areas (3224) are provided with medium passages (3225) in communication with the heat exchange cavities (3221) corresponding to the through holes, and the sealing ring covers (3231) have medium ring cavities (3234) inside. The heat exchange medium enters the medium ring cavities (3234) through the inflow pipes (3232) and then enters the heat exchange cavities (3221), and flows out of the heat exchange cavities (3221) through the outflow pipes (3233) of the sealing ring covers (3231) on the other side.

2. The purification method of high-purity fluorocarbonate-based solvent according to claim 1, characterized by, Step S3 further comprises: S31, the collection assembly (33) melts the crystals on the surface of the crystallization plate (322) by hot air; S32, the melted crystals obtained in S31 are transported into the recrystallization area, crystallized by the rotating crystal plate group (32) in the recrystallization area, and then collected by the collection assembly (33) in the recrystallization area and output.

3. The purification method of high purity fluoro-carbonate based solvent according to claim 2, characterized in that: The crystallization pool (31) is provided with a region spacing plate (311), the region spacing plate (311) is arranged on the side of the crystallization pool (31) away from the liquefaction and separation module (2), the region spacing plate (311) divides the crystallization pool (31) into a recrystallization area, the rotating crystal plate group (32) is arranged in the recrystallization area, and the crystals collected by the collection assembly (33) in the crystallization pool (31) are transported to the recrystallization area after being melted by heating.

4. The purification method of high purity fluoro-carbonate based solvent according to claim 1, characterized in that: In step S2, the temperature of the crystallization pool (31) is higher than the melting point of the fluorocarbonate-based solvent to be purified, and the temperature of the heat exchange medium in the heat exchange cavity (3221) is lower than the melting point of the fluorocarbonate-based solvent to be purified.

5. The purification method of high purity fluoro-carbonate based solvent according to claim 1, characterized in that: In step S1, the liquefaction separation module (2) comprises a cooling cavity (21) and the cyclone separator (22), the cyclone separator (22) is arranged in the cooling cavity (21), the cooling cavity (21) is provided with an input pipe (23) at the bottom, the input pipe (23) spirally ascends around the cyclone separator (22) and is connected with the cyclone separator (22) tangentially, and the cooling cavity (21) is used for heat exchange with the crude gas in the input pipe (23) to liquefy the crude gas and then separate the gas-liquid in the cyclone separator (22).

6. The purification method of high purity fluoro-carbonate based solvent according to claim 1, characterized in that: The collecting assembly (33) comprises a collecting arc groove (331), a collecting pipeline (332), a supporting arc plate (333) and a blowing pipeline (334), the collecting arc groove (331) is arranged on both sides of the crystallization plate (322) and above the crystallization driving assembly (321), the supporting arc plate (333) is arranged below the collecting arc groove (331), the supporting arc plate (333) is provided with a heating gas path (3331) therein, the collecting pipeline (332) is communicated with the collecting arc groove (331) and is used for conveying the melted liquid in the collecting arc groove (331), and the blowing pipeline (334) is arranged above both sides of the crystallization plate (322) and is used for blowing hot air to the inner recessed area (3222) of the crystallization plate (322).

7. The purification method of high purity fluoro-carbonate based solvent according to claim 6, characterized in that: One side of the supporting arc plate (333) close to the crystallization plate (322) is provided with an upward blowing nozzle (3332), the upward blowing nozzle (3332) is used for blowing upward air flow and making the air flow flow along the mounting area (3224) to the outer convex area (3223), and the other side of the supporting arc plate (333) away from the crystallization plate (322) is provided with a blowing nozzle (3333), the blowing nozzle (3333) is used for blowing downward air flow to displace the crystallization plate (322) below the supporting arc plate (333).

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