Static melt crystallizer with local heat exchange structure
Patent Information
- Application Number
- CN202621439752.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-14
- Publication Date
- 2026-10-20
- Estimated Expiration
- 2036-09-14
AI Technical Summary
[0005]本实用新型的目的在于提供一种带局部换热结构的静态熔融结晶器，以解决现有静态熔融结晶器内部换热不足、发汗阶段局部加热能力弱、晶层稳定性不足以及发汗液或熔融液下行排出不够顺畅的问题
[0015]本实用新型至少包括以下有益效果：本实用新型通过在釜体内部设置刺刀管换热系统，使静态熔融结晶器除外部换热夹套外，还具有内部换热结构，能够缩短结晶腔内物料的传热路径，提高结晶阶段和发汗阶段的换热效率；通过刺刀管换热系统在发汗阶段通入加热介质，可对刺刀管外管附近晶层进行具有针对性的局部加热，使局部低纯度晶层、晶间残液及表面残液优先熔出；通过在刺刀管外管外侧设置导热翅片，可增加换热面积、稳定晶层，并为发汗液及熔融液沿轴向下行提供导流界面；通过设置导汗微槽，可进一步改善发汗液和熔融液沿刺刀管方向的下行过程；通过在结晶腔下部设置不锈钢烧结滤板，可对晶层起到承托作用，并允许母液、发汗液及熔融液进入下封头后由出料口排出。
Smart Images
Figure CN224864950U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of chemical separation and refining equipment. More specifically, this utility model relates to a static melt crystallizer with a local heat exchange structure. Background Technology
[0002] Melt crystallization is a technique that separates and purifies materials by utilizing the differences in freezing points or solid-liquid equilibrium among their components. It is suitable for some low-melting-point organic compounds, heat-sensitive organic compounds, and material systems that are not suitable for prolonged high-temperature distillation. Static melt crystallization typically includes operations such as cooling crystallization, discharging mother liquor, sweating, and product melting. It features relatively simple equipment structure, lower operating temperature, and higher product purity.
[0003] Existing static melt crystallizers mostly rely on jackets, heat exchange plates, or heat exchange tubes for overall cooling and heating. During the crystallization stage, if only the external jacket is used for heat exchange, the heat transfer path in the central area of the crystallization chamber is relatively long, easily leading to uneven cooling, insufficient crystallization efficiency, and uneven crystal layer distribution. During the sweating stage, if only overall heating is used, it is difficult to selectively melt localized low-purity crystal layers, intergranular residues, and surface residues. Furthermore, when the sweating liquid or molten liquid flows downwards between the crystal layers and heat exchange components, local stagnation may occur if there is no suitable guiding interface, thus affecting drainage efficiency and product stability.
[0004] Taking ε-caprolactone as an example, industrial-grade ε-caprolactone typically contains impurities such as light components, heavy components, moisture, organic acids, color substances, and small amounts of oligomers. For polymerization applications, high purity is required, making further refining via melt crystallization suitable. Therefore, it is necessary to provide a static melt crystallizer capable of achieving internal and external composite heat exchange, localized heating and sweating, crystal layer stabilization, and liquid phase flow guidance. Utility Model Content
[0005] The purpose of this invention is to provide a static melt crystallizer with a local heat exchange structure to solve the problems of insufficient internal heat exchange, weak local heating capacity during the sweating stage, insufficient crystal layer stability, and insufficient downward discharge of sweating liquid or molten liquid in existing static melt crystallizers.
[0006] A static melting crystallizer with a local heat exchange structure includes a vessel body with a crystallization chamber inside. The vessel body is provided with a material inlet and a nitrogen inlet. A heat exchange jacket is provided on the outside of the vessel body. The heat exchange jacket is provided with a jacket inlet and a jacket outlet. A lower end cap is provided at the bottom of the vessel body, and a discharge port is provided on the lower end cap. The vessel body is equipped with a bayonet tube heat exchange system; The bayonet tube heat exchange system includes a bayonet tube heat exchange medium inlet and a bayonet tube heat exchange medium outlet. A heat exchange medium distribution cavity is provided below which an upper tube sheet is provided, and a lower tube sheet is provided below the upper tube sheet; Multiple bayonet tubes are attached to the lower tube sheet at their upper ends, and the lower ends of the bayonet tubes are provided with bayonet tube closed ends; the multiple bayonet tubes extend into the crystallization cavity; Each bayonet tube outer tube is provided with a bayonet tube inner tube, the upper end of which is fixedly connected to the upper tube sheet; a heat exchange medium return channel is provided between the bayonet tube outer tube and the bayonet tube inner tube; The bayonet tube heat exchange medium inlet is connected to the heat exchange medium distribution cavity; the bayonet tube heat exchange medium outlet is connected to the heat exchange medium return channel. The outer side of the bayonet tube is equipped with a sweat-wicking structure.
[0007] Preferably, the sweat-wicking structure includes a plurality of heat-conducting fins extending along the length of the outer tube of the bayonet tube.
[0008] Preferably, a number of heat-conducting fins are distributed at intervals along the circumference of the outer tube of the bayonet tube.
[0009] Preferably, the heat-conducting fins are sheet-like or rib-like structures extending axially along the outer tube of the bayonet tube.
[0010] Preferably, the sweat-guiding structure further includes sweat-guiding microgrooves, which are disposed on the outer surface of the bayonet tube and / or the surface of the heat-conducting fins.
[0011] Preferably, the heat exchange jacket is arranged around the outside of the vessel body, the jacket inlet is located at the lower part of the heat exchange jacket, and the jacket outlet is located at the upper part of the heat exchange jacket.
[0012] Preferably, a stainless steel sintered filter plate is provided at the lower part of the crystallization chamber, and the stainless steel sintered filter plate is located above the lower end cap.
[0013] Preferably, a sealing gasket is provided on the outer periphery of the stainless steel sintered filter plate.
[0014] Preferably, a support frame is provided below the stainless steel sintered filter plate.
[0015] This invention offers at least the following advantages: By incorporating a heat exchange system with a bayonet tube inside the vessel, the static melting crystallizer, in addition to its external heat exchange jacket, possesses an internal heat exchange structure, which shortens the heat transfer path of materials within the crystallization chamber and improves the heat exchange efficiency during the crystallization and sweating stages. During the sweating stage, the introduction of a heating medium through the bayonet tube heat exchange system allows for targeted local heating of the crystal layer near the outer tube, preferentially melting out localized low-purity crystal layers, intergranular residual liquid, and surface residual liquid. The addition of heat-conducting fins on the outer side of the bayonet tube increases the heat exchange area, stabilizes the crystal layer, and provides a guiding interface for the downward flow of sweating liquid and molten liquid along the axial direction. The inclusion of sweat-guiding microgrooves further improves the downward flow of sweating liquid and molten liquid along the bayonet tube direction. Finally, the installation of a stainless steel sintered filter plate at the bottom of the crystallization chamber supports the crystal layer and allows the mother liquor, sweating liquid, and molten liquid to enter the lower head and be discharged through the outlet.
[0016] Other advantages, objectives and features of this invention will be apparent in part from the description which follows, and in part from the understanding of those skilled in the art through study and practice of this invention. Attached Figure Description
[0017] Figure 1 is a schematic diagram of the overall structure of the static melting crystallizer with local heat exchange structure of this utility model; Figure 2 is a front structural schematic diagram of the static melting crystallizer with local heat exchange structure of this utility model; Figure 3 is a cross-sectional schematic diagram of the static melting crystallizer with local heat exchange structure of this utility model; Figure 4 is a schematic diagram of the axial cross-sectional structure of the bayonet tube heat exchange system of this utility model; Figure 5 is a schematic diagram of the radial cross-sectional structure of the bayonet tube heat exchange system of this utility model; Figure 6 is a schematic diagram of the cross-sectional structure of the outer tube and inner tube of the bayonet tube of this utility model; Figure 7 is a partial cross-sectional structural diagram of the outer tube and inner tube of the bayonet tube of this utility model; Figure 8 is a cross-sectional structural diagram of the lower end cap, discharge port, stainless steel sintered filter plate, sealing gasket and support frame of this utility model. Figure 9 is a top view of the stainless steel sintered filter plate of this utility model.
[0018] The structural names corresponding to the labels in the diagram are as follows: 1. Kettle body; 11. Crystallization chamber; 12. Material inlet; 13. Nitrogen inlet; 2. Bayonet tube heat exchange system; 21. Bayonet tube heat exchange medium inlet; 22. Bayonet tube heat exchange medium outlet; 23. Heat exchange medium distribution chamber; 24. Upper tube sheet; 25. Lower tube sheet; 26. Bayonet outer tube; 261. Heat exchange medium reflux channel; 27. Bayonet inner tube; 28. Bayonet closed end; 3. Heat exchange jacket; 31. Jacket inlet; 32. Jacket outlet; 4. Sweat-guiding structure; 41. Heat-conducting fins; 42. Sweat-guiding microgroove; 5. Lower head; 51. Discharge port; 52. Stainless steel sintered filter plate; 53. Sealing gasket; 54. Support frame; 55. Lower head liquid collection chamber. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.
[0020] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.
[0021] like Figures 1-9 As shown, a static melt crystallizer with a local heat exchange structure includes a vessel body 1, which contains a crystallization chamber 11 for containing the material to be refined. The vessel body 1 is provided with a material inlet 12 and a nitrogen inlet 13. The material inlet 12 is connected to the crystallization chamber 11 and is used to add the material to be refined into the crystallization chamber 11. The nitrogen inlet 13 is connected to the crystallization chamber 11 and is used to introduce nitrogen into the vessel body 1 before and after feeding, draining, or maintenance for replacement or protection. A heat exchange jacket 3 is provided on the outside of the vessel body 1. The heat exchange jacket 3 is provided with a jacket inlet 31 and a jacket outlet 32. The heat exchange medium enters the heat exchange jacket 3 through the jacket inlet 31 and exits through the jacket outlet 32. The heat exchange jacket 3 is used to cool or heat the material in the crystallization chamber 11 as a whole.
[0022] The lower part of the vessel body 1 is provided with a lower end cap 5, and a discharge port 51 is provided on the lower end cap 5. A lower end cap liquid collection chamber 55 communicating with the discharge port 51 is provided above the discharge port 51. The discharge port 51 is used to discharge the uncrystallized mother liquor, sweating liquid and the final melted product liquid at different operation stages. The vessel body 1 is equipped with a bayonet tube heat exchange system 2; The bayonet tube heat exchange system 2 includes a bayonet tube heat exchange medium inlet 21 and a bayonet tube heat exchange medium outlet 22; A heat exchange medium distribution cavity 23 is provided below an upper tube sheet 24, and a lower tube sheet 25 is provided below the upper tube sheet 24. Multiple bayonet tubes 26 have their upper ends fixedly connected to the lower tube plate 25, and the lower ends of the bayonet tubes 26 are provided with bayonet tube closed ends 28; the multiple bayonet tubes 26 extend into the crystallization cavity 11; Each bayonet tube outer tube 26 is provided with a bayonet tube inner tube 27 inside, and the upper end of the bayonet tube inner tube 27 is fixedly connected to the upper tube plate 24; a heat exchange medium return channel 261 is provided between the bayonet tube outer tube 26 and the bayonet tube inner tube 27; The bayonet tube heat exchange medium inlet 21 is connected to the heat exchange medium distribution cavity 23 and the heat exchange medium return channel 261; the bayonet tube heat exchange medium outlet 22 is connected to the heat exchange medium return channel 261. A sweat-wicking structure 4 is provided on the outer side of the bayonet tube.
[0023] The heat exchange medium enters the heat exchange medium distribution chamber 23 through the bayonet tube heat exchange medium inlet 21, and then enters the inner tube 27 of the bayonet tube. It then turns back near the closed end 28 of the bayonet tube, returns through the channel between the inner tube 27 and the outer tube 26 of the bayonet tube, and is discharged through the bayonet tube heat exchange medium outlet 22. In other embodiments, the opposite flow direction of the heat exchange medium can be used depending on the equipment layout and heat exchange requirements.
[0024] Working principle: During use, the ε-caprolactone material to be refined is added into the crystallization chamber 11 through the material inlet 12. Nitrogen can be introduced through the nitrogen inlet 13 as needed to reduce the risk of the material coming into contact with air or moisture. Subsequently, a cooling medium is introduced through the heat exchange jacket 3 and the bayonet tube heat exchange system 2, causing the ε-caprolactone material to undergo static melting and crystallization within the crystallization chamber 11. Because the bayonet tube heat exchange system 2 is distributed inside the crystallization chamber 11, it shortens the heat transfer path in the central region of the crystallization chamber 11, improving the problem of slow cooling in the central region when relying solely on the external heat exchange jacket 3 for heat exchange.
[0025] After crystallization, the uncrystallized mother liquor flows downward through the stainless steel sintered filter plate 52 into the lower head collection chamber 55 and is discharged through the outlet 51. After the mother liquor is discharged, the bayonet tube heat exchange system 2 can be switched to a heating medium to locally heat and sweat the crystal layer near the bayonet tube outer tube 26 and the sweat-guiding structure 4. The sweat generated during the sweating process flows downward along the sweat-guiding structure 4, enters the lower head collection chamber 55, and is discharged through the outlet 51. After sweating is completed, the remaining crystals are heated through the heat exchange jacket 3 and / or the bayonet tube heat exchange system 2 until they melt and are discharged through the outlet 51.
[0026] This embodiment uses ε-caprolactone as the material to be refined. It should be understood that ε-caprolactone is only one of the preferred materials for this invention, and the structure of this invention is not limited to ε-caprolactone; it can also be used for other materials suitable for refining by static melt crystallization.
[0027] In the above technical solution, the sweat-guiding structure 4 includes six heat-conducting fins extending along the length of the outer tube of the bayonet tube 26. The heat-conducting fins 41 further expand the effective contact heat exchange area between the outer tube of the bayonet tube 26 and the material in the crystallization cavity 11, which is beneficial to improving the crystallization efficiency and improving the crystal layer distribution. On the other hand, the heat-conducting fins 41 can support and stabilize the crystal layer attached to the outer tube of the bayonet tube 26 during the crystallization stage, and provide a guiding interface for the liquid phase to flow downward along the axis during the sweating and melting stages.
[0028] In the above technical solution, a number of heat-conducting fins 41 are distributed at intervals along the circumference of the outer tube 26 of the bayonet tube.
[0029] In the above technical solution, the heat-conducting fins 41 are sheet-like or rib-like structures extending axially along the outer tube 26 of the bayonet tube. The heat-conducting fins 41 can be sheet-like, rib-like, arc-shaped sheet-like, corrugated sheet-like, or grooved sheet-like structures. In this embodiment, six heat-conducting fins 41 are provided on the outer side of each bayonet tube 26, and the six heat-conducting fins 41 are evenly distributed circumferentially along the outer tube 26. It should be understood that six heat-conducting fins 41 are only a preferred arrangement in this embodiment; in other embodiments, the number, circumferential spacing, and cross-sectional shape of the heat-conducting fins 41 can be adjusted according to the heat exchange area, crystal layer support, and liquid phase flow requirements.
[0030] In the above technical solution, the sweat-guiding structure 4 further includes sweat-guiding microgrooves 42. These microgrooves 42 are disposed on the outer surface of the outer tube 26 of the bayonet tube and the surface of the heat-conducting fins 41. During the sweating process, the sweat generated flows downwards along the heat-conducting fins 41 and the sweat-guiding microgrooves 42. The sweat-guiding microgrooves 42 provide a downward interface for the liquid phase during the sweating and melting stages, allowing the mother liquor, sweating liquid, or molten liquid to flow downwards along the axial direction of the outer tube 26 of the bayonet tube and the heat-conducting fins 41, thereby reducing localized retention of the liquid phase in the tube bundle gaps. The liquid phase includes uncrystallized mother liquor, sweat generated during the sweating stage, and the product melt formed during the final melting stage.
[0031] In the above technical solution, the heat exchange jacket 3 is arranged around the outside of the vessel body 1, the jacket inlet 31 is located at the lower part of the heat exchange jacket 3, and the jacket outlet 32 is located at the upper part of the heat exchange jacket 3.
[0032] In the above technical solution, a stainless steel sintered filter plate 52 is provided at the lower part of the crystallization cavity 11. The stainless steel sintered filter plate 52 is located above the lower end cap 5. The stainless steel sintered filter plate 52 is used to support the crystal layer formed in the crystallization cavity 11 and allow the liquid phase to pass downward.
[0033] In the above technical solution, a sealing gasket 53 is provided on the outer periphery of the stainless steel sintered filter plate 52. The sealing gasket 53 is used to reduce the flow of liquid phase around the outer periphery of the stainless steel sintered filter plate 52.
[0034] In the above technical solution, a support frame 54 is provided below the stainless steel sintered filter plate 52. The support frame 54 is used to support the stainless steel sintered filter plate 52 and improve its stress stability.
[0035] This invention achieves internal and external composite heat exchange, localized heating and sweating, crystal layer support and stability, and axial flow guidance of the liquid phase during the static melting and crystallization process through the cooperation of the vessel body 1, the bayonet tube heat exchange system 2, the heat exchange jacket 3, the sweat-guiding structure 4, and the lower end cap 5. The overall structure is simple and easy to manufacture, disassemble, clean, and maintain.
[0036] The number of devices and processing scale described herein are for the purpose of simplifying the description of this utility model. Applications, modifications, and variations of this utility model will be readily apparent to those skilled in the art.
[0037] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.
Claims
1. A static melting crystallizer with a local heat exchange structure, comprising a vessel body having a crystallization chamber therein, a material inlet and a nitrogen inlet on the vessel body, a heat exchange jacket on the outer side of the vessel body having a jacket inlet and a jacket outlet, and a lower end cap having a discharge port at the lower part of the vessel body, characterized in that, The vessel body is equipped with a bayonet tube heat exchange system; The bayonet tube heat exchange system includes a bayonet tube heat exchange medium inlet and a bayonet tube heat exchange medium outlet. A heat exchange medium distribution cavity is provided below which an upper tube sheet is provided, and a lower tube sheet is provided below the upper tube sheet; Multiple bayonet tubes are attached to the lower tube sheet at their upper ends, and the lower ends of the bayonet tubes are provided with bayonet tube closed ends; the multiple bayonet tubes extend into the crystallization cavity; Each bayonet tube outer tube is provided with a bayonet tube inner tube, the upper end of which is fixedly connected to the upper tube sheet; a heat exchange medium return channel is provided between the bayonet tube outer tube and the bayonet tube inner tube; The bayonet tube heat exchange medium inlet is connected to the heat exchange medium distribution cavity; the bayonet tube heat exchange medium outlet is connected to the heat exchange medium return channel. The outer side of the bayonet tube is equipped with a sweat-wicking structure.
2. The static melting crystallizer with a local heat exchange structure according to claim 1, characterized in that, The sweat-wicking structure includes several heat-conducting fins extending along the length of the outer tube of the bayonet tube.
3. The static melting crystallizer with a local heat exchange structure according to claim 2, characterized in that, Several heat-conducting fins are distributed at intervals along the circumference of the outer tube of the bayonet tube.
4. The static melting crystallizer with a local heat exchange structure according to claim 2, characterized in that, The heat-conducting fins are sheet-like or rib-like structures extending axially along the outer tube of the bayonet tube.
5. The static melting crystallizer with a local heat exchange structure according to claim 2, characterized in that, The sweat-guiding structure also includes sweat-guiding microgrooves, which are disposed on the outer surface of the outer tube of the bayonet tube and / or the surface of the heat-conducting fins.
6. The static melting crystallizer with a local heat exchange structure according to claim 1, characterized in that, The heat exchange jacket is arranged around the outside of the vessel body, with the jacket inlet located at the lower part of the heat exchange jacket and the jacket outlet located at the upper part of the heat exchange jacket.
7. The static melting crystallizer with a local heat exchange structure according to claim 1, characterized in that, A stainless steel sintered filter plate is provided at the lower part of the crystallization chamber, and the stainless steel sintered filter plate is located above the lower end cap.
8. The static melting crystallizer with a local heat exchange structure according to claim 7, characterized in that, The stainless steel sintered filter plate is provided with a sealing gasket on its outer periphery.
9. The static melting crystallizer with a local heat exchange structure according to claim 7, characterized in that, A support frame is provided below the stainless steel sintered filter plate.