Crystallization reaction kettle and crystallization control method

Abstract

The application relates to the technical field of chemical crystallization equipment, and provides a crystallization reaction kettle and a crystallization control method. The crystallization reaction kettle comprises a kettle body provided with a reaction cavity for containing mother liquor; a heat pipe stirring assembly, a stirring end of the heat pipe stirring assembly is arranged in the reaction cavity, and the stirring end of the heat pipe stirring assembly is used for stirring the mother liquor and absorbing heat in the mother liquor, so that a first temperature area is formed in the reaction cavity; and a wall surface temperature control assembly arranged on the outer wall of the kettle body and used for adjusting the temperature of the inner wall of the kettle body, so that a second temperature area is formed on the inner wall of the kettle body. The temperature of the first temperature area is T1, the temperature of the second temperature area is T2, the crystallization precipitation temperature of the mother liquor is T0, and T2>T0>T1 is met. The crystallization area can be transferred to the inside of the mother liquor, the target solute can preferentially reach the crystallization precipitation condition in the inside of the mother liquor, crystallization of the mother liquor near the inner wall of the kettle body can be inhibited, the adhesion probability of crystals on the inner wall of the kettle body can be reduced, and the continuous operation capacity of the crystallization reaction kettle can be improved.

Description

Technical Field

[0001] This application relates to the field of chemical crystallization equipment technology, and in particular to a crystallization reactor and a crystallization control method. Background Technology

[0002] Crystallization reactors are commonly used crystallization equipment in industries such as chemical, pharmaceutical, and food processing. They typically work by cooling the material to achieve a supersaturated solution, thereby causing the target solute to precipitate in crystal form. Currently, the most commonly used crystallization equipment is the jacketed crystallizer. The reactor body usually adopts a jacketed structure, where a low-temperature heat exchange medium enters the jacket and exchanges heat with the material inside the reactor to lower the material temperature and promote the crystallization of the solute.

[0003] However, when using vessel wall heat exchange for cooling crystallization, the inner wall of the vessel is usually the primary heat exchange surface, easily leading to a large local temperature gradient between the inner wall and the material. When the temperature of the inner wall drops below the crystallization precipitation temperature, the material near the inner wall tends to reach supersaturation first, and crystal nucleation and precipitation occur at the inner wall, forming crystal scales that adhere to it. As the crystallization process continues, the crystal scales gradually thicken, not only occupying effective space within the vessel but also increasing the thermal resistance between the vessel wall and the material, causing a gradual decrease in heat exchange efficiency. This can even prevent the material from cooling effectively further, affecting the normal progress of the crystallization process.

[0004] Existing technologies utilize mechanical scraping structures such as scrapers and scraper rings on the stirring shaft to remove adhering crystals through the relative movement of the scrapers against the inner wall of the reactor during stirring. However, this method is a passive removal approach, which is insufficient to inhibit crystal formation on the inner wall of the reactor during the crystallization nucleation stage. Furthermore, the continuous contact between the scraper and the inner wall of the reactor may generate friction and wear, posing a risk that abrasive particles may enter the material and affect product quality. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this application provides a crystallization reactor and a crystallization control method. The technical problem to be solved by this application is achieved through the following technical solution: In a first aspect, this application provides a crystallization reactor, comprising: The vessel body has a reaction chamber for containing the mother liquor; A heat pipe stirring assembly has its stirring end located in the reaction chamber. The stirring end of the heat pipe stirring assembly is used to stir the mother liquor and absorb heat from the mother liquor, so as to form a first temperature zone in the reaction chamber. The wall temperature control component is installed on the outer wall of the vessel to regulate the temperature of the inner wall of the vessel so that the inner wall of the vessel forms a second temperature zone; the temperature of the first temperature zone is T1, the temperature of the second temperature zone is T2, and the crystallization temperature of the mother liquor is T0, satisfying that T2 > T0 > T1.

[0006] In one feasible embodiment, the heat pipe stirring assembly includes: A heat pipe stirring shaft is partially located within the reaction chamber; A heat pipe stirring paddle is connected to a heat pipe stirring shaft and is placed in the reaction chamber, forming a stirring end. The stirring drive is connected to the heat pipe stirring shaft. The stirring drive is used to drive the heat pipe stirring shaft to rotate, so as to drive the heat pipe stirring paddle to rotate in the reaction chamber.

[0007] In one feasible manner, the heat pipe stirring shaft has a first internal cavity; The heat pipe agitator has a second internal cavity; The second internal cavity is connected to the first internal cavity, and a phase change working fluid is disposed in both the first and second internal cavities.

[0008] In one feasible approach, there are multiple heat pipe agitators, which are spaced apart along the axial direction of the heat pipe agitator shaft. A heat pipe impeller includes multiple heat pipe blades, which are spaced apart circumferentially along the heat pipe stirring shaft.

[0009] In one feasible approach, the wall temperature control component includes: A heating jacket is disposed on the outer wall of the vessel body. The heating jacket has a first medium inlet and a first medium outlet that are connected. The heating jacket is used to contain the temperature control medium entering through the first medium inlet. The temperature control medium is used to exchange heat with the outer wall of the vessel body to regulate the temperature of the inner wall of the vessel body.

[0010] In one feasible embodiment, the vessel body includes: The body has an opening at one end; The vessel lid is detachably connected to the open end of the main body. The vessel lid and the main body enclose a reaction chamber, and a heat pipe stirring assembly is installed through the vessel lid.

[0011] In one feasible approach, the stirring end of the heat pipe stirring assembly is the evaporation section, and the end of the heat pipe stirring assembly away from the stirring end is the condensation section. The evaporation section is used to absorb heat from the mother liquor, and the condensation section is used to release heat. The crystallization reactor also includes: The waste heat recovery component is located on the outside of the condensing section and exchanges heat with the condensing section to absorb the heat released by the condensing section.

[0012] In one feasible approach, the waste heat recovery assembly includes: A water-cooled jacket is fitted over the outside of the condensing section of the heat pipe stirring assembly. The water-cooled jacket has a second medium inlet and a second medium outlet. The water-cooled jacket is used to contain the heat exchange medium entering through the second medium inlet. The heat exchange medium is used to exchange heat with the condensing section to absorb the heat released by the condensing section.

[0013] In one feasible embodiment, the crystallization reactor also includes: The temperature detection component includes: a first temperature sensor and a second temperature sensor; The first temperature sensor is disposed inside the reaction chamber and corresponds to the first temperature region, and is used to detect the temperature of the first temperature region. The second temperature sensor is located on the inner wall of the vessel and corresponds to the second temperature zone, and is used to detect the temperature of the second temperature zone.

[0014] Secondly, this application provides a crystallization control method, applied to the crystallization reactor provided in the first aspect of this application, comprising the following steps: Add the mother liquor into the reaction chamber; The mother liquor is stirred by the stirring end of the heat pipe stirring assembly, and the heat in the mother liquor is absorbed to form a first temperature zone in the reaction chamber. The temperature of the inner wall of the vessel is adjusted by the wall temperature control component so that the inner wall of the vessel forms a second temperature zone. The temperature T1 of the first temperature region, the temperature T2 of the second temperature region, and the crystallization temperature T0 of the mother liquor are obtained. The temperatures of the first and second temperature regions are controlled to satisfy T2 > T0 > T1, so that the first temperature region reaches the crystallization condition of the mother liquor and the crystallization of the mother liquor in the second temperature region is inhibited.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: The crystallization reactor provided in this application absorbs heat directly from the mother liquor through a heat pipe stirring assembly, creating a first temperature zone inside the mother liquor with a temperature lower than the crystallization precipitation temperature. Simultaneously, a wall temperature control assembly installed on the outer wall of the reactor regulates the temperature of the inner wall of the reactor, creating a second temperature zone inside the reactor with a temperature higher than the crystallization precipitation temperature. This transfers the crystallization zone from the vicinity of the traditional reactor wall heat exchange surface to the interior of the mother liquor, allowing the target solute to preferentially reach the crystallization precipitation conditions inside the mother liquor. At the same time, it inhibits crystallization of the mother liquor near the inner wall of the reactor, thereby reducing the probability of crystal adhesion to the inner wall of the reactor. This avoids the risks of reactor friction and wear and material contamination caused by mechanical scraping, and improves the continuous operation capability of the crystallization reactor. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic diagram of the structure of a crystallization reactor according to an embodiment of this application is shown; Figure 2 A schematic diagram of the structure of a heat pipe stirring assembly according to an embodiment of this application is shown; Figure 3 It shows Figure 2 A schematic diagram of the cross-sectional structure of the HH plane; Figure 4 It shows Figure 2 A schematic diagram of the cross-sectional structure of the AA surface in the middle; Figure 5 A top view of the lid of the vessel according to an embodiment of this application is shown; Figure 6 A flowchart illustrating the steps of a crystallization control method according to an embodiment of this application is shown.

[0017] Figure label: 1. Reactor body; 11. Main body; 111. Discharge port; 112. Bottom valve; 12. Reactor lid; 121. Center mounting hole; 1211. Positioning bearing; 122. Center temperature measuring port; 123. Inner wall temperature measuring port; 124. Instrument mounting port; 125. Feed inlet; 126. Vent port; 2. Heat pipe stirring assembly; 21. Heat pipe stirring shaft; 22. Heat pipe stirring paddle; 221. Heat pipe blades; 2211. Stirring component; 2212. Central tube; 23. Stirring drive component; 231. Drive motor; 232. Reducer; 233. Sealed coupling; 3. Heating jacket; 31. First medium inlet; 311. First inlet temperature sensor; 32. First medium outlet; 321. First outlet temperature sensor; 4. Water-cooled jacket; 41. Second medium inlet; 411. Second inlet temperature sensor; 42. Second medium outlet; 421. Second outlet temperature sensor; 5. First temperature sensor; 6. Second temperature sensor; 7. Pressure sensor. Detailed Implementation

[0018] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments and application scenarios. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Unless otherwise specified, the following embodiments and features can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present application are within the scope of protection of the present application.

[0019] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] Please see Figure 1 , Figure 1 A schematic diagram of a crystallization reactor according to an embodiment of this application is shown.

[0021] The crystallization reactor provided in this application includes: a reactor body 1, a heat pipe stirring assembly 2, and a wall temperature control assembly. The reactor body 1 has a reaction chamber for containing the mother liquor. During crystallization, the solubility of the target solute is reduced by lowering the temperature of the mother liquor. When the concentration of the target solute exceeds the equilibrium solubility at the corresponding temperature, the mother liquor enters a supersaturated state, and crystal nucleation and growth further occur. The stirring end of the heat pipe stirring assembly 2 is disposed in the reaction chamber. The stirring end of the heat pipe stirring assembly 2 is used to stir the mother liquor and absorb heat from the mother liquor, thereby forming a first temperature zone within the reaction chamber. The wall temperature control assembly is disposed on the outer wall of the reactor body 1. The wall temperature control assembly is used to regulate the temperature of the inner wall of the reactor body 1, thereby forming a second temperature zone within the inner wall of the reactor body 1.

[0022] Specifically, the heat pipe stirring assembly 2 has a heat pipe structure, and its stirring end can be immersed in the mother liquor. When the heat pipe stirring assembly 2 is running, the stirring end applies mechanical disturbance to the mother liquor, causing it to flow within the reaction chamber. Furthermore, direct heat exchange occurs between the stirring end and the mother liquor, transferring heat from the mother liquor to the outside of the reaction chamber through the heat pipe structure. Since the heat exchange location of the heat pipe stirring assembly 2 is inside the mother liquor, after continuous operation, a local temperature field with a temperature lower than that of the main body of the reaction chamber can be formed around the stirring end. This region constitutes the first temperature region. Controlling the heat exchange between the wall temperature control assembly and the vessel body 1 maintains the inner wall of the vessel body 1 within a preset temperature range, thereby forming a second temperature region with a temperature higher than that of the main body of the reaction chamber in the adjacent area of ​​the inner wall of the vessel body 1.

[0023] In this embodiment, the temperature of the first temperature region is T1, the temperature of the second temperature region is T2, and the crystallization temperature of the mother liquor is T0, satisfying T2 > T0 > T1. Since T1 < T0, the mother liquor in the first temperature region can reach the crystallization precipitation condition. When the target solute in the mother liquor reaches the corresponding supersaturation state, crystals can form near the first temperature region. Even if there is a low-temperature surface on the inner wall of the vessel 1, the inner wall of the vessel 1 is heated or kept warm by the wall temperature control component, so that the temperature of the second temperature region of the inner wall of the vessel 1 is T2 > T0, thereby making the temperature of the mother liquor near the inner wall of the vessel 1 higher than the crystallization precipitation temperature, reducing the possibility that the mother liquor near the inner wall of the vessel 1 will reach the crystallization precipitation condition, and inhibiting the nucleation and adhesion of crystals on the inner wall of the vessel 1. Therefore, by controlling T2 > T0 > T1 in this embodiment, a low-temperature region conducive to crystal precipitation can be formed inside the reaction chamber, while the region adjacent to the inner wall of the vessel 1 is kept at a high-temperature state that inhibits crystal precipitation, thereby establishing a differentiated temperature field with specific temperature distribution characteristics along the direction from the inside of the mother liquor to the inner wall of the vessel 1. It should be understood that the crystallization temperature refers to the temperature at which the target solute can reach the crystallization conditions under the current mother liquor composition and process conditions. The crystallization temperature can be different for different types and concentrations of mother liquor. The crystallization temperature can be determined based on the physical properties, concentration, and process conditions of the actual mother liquor to be treated.

[0024] In this embodiment of the crystallization reactor, heat exchange is achieved between the heat pipe stirring assembly 2 and the mother liquor. This shifts the primary heat absorption location from the inner wall of the reactor body 1 to the interior of the mother liquor. A wall temperature control assembly maintains the inner wall of the reactor body 1 above the crystallization precipitation temperature, spatially separating the low-temperature region required for crystallization from the inner wall region of the reactor body 1. This reduces the crystallization driving force at the inner wall and lowers the probability of crystal nucleation at the reactor wall, suppressing wall adhesion from the initial stage of crystallization. This avoids the risks of reactor friction and wear, and material contamination caused by mechanical scraping. Furthermore, in this embodiment, the stirring end of the heat pipe stirring assembly 2 is directly immersed in the mother liquor, allowing the heat pipe stirring assembly 2 to directly absorb heat from within the mother liquor. Compared to the traditional method of relying on the reactor body 1 wall for heat exchange, this effectively shortens the heat transfer path, reduces the limitations imposed by the reactor body 1 wall on the heat transfer process, and improves the heat extraction efficiency and cooling response speed of the mother liquor. This facilitates the rapid formation of a low-temperature region within the mother liquor that meets the crystallization conditions.

[0025] Please see Figure 2In this embodiment, the heat pipe stirring assembly 2 includes a heat pipe stirring shaft 21, a heat pipe stirring paddle 22, and a stirring drive 23. The heat pipe stirring shaft 21 is partially disposed within the reaction chamber. The heat pipe stirring paddle 22 is connected to the heat pipe stirring shaft 21 and disposed within the reaction chamber, forming a stirring end. The stirring drive 23 is connected to the heat pipe stirring shaft 21 and drives the heat pipe stirring shaft 21 to rotate, thereby causing the heat pipe stirring paddle 22 to rotate within the reaction chamber.

[0026] Specifically, the heat pipe stirring shaft 21 is vertically arranged along the central axis of the vessel body 1, passing through the top of the vessel body 1 and extending into the reaction chamber. The heat pipe stirring paddle 22 can be immersed in the mother liquor, and the heat pipe stirring paddle 22 stirs the mother liquor under the drive of the heat pipe stirring shaft 21, while exchanging heat with the mother liquor. Optionally, the surfaces of the heat pipe stirring shaft 21 and the heat pipe stirring paddle 22 have an anti-corrosion coating to prevent corrosion of the mother liquor.

[0027] In one embodiment, the stirring drive 23 includes a drive motor 231, a reducer 232, and a sealed coupling 233. The output end of the drive motor 231 is connected to the reducer 232, and the output end of the reducer 232 is connected to the heat pipe stirring shaft 21 via the sealed coupling 233. The rotational power output by the drive motor 231 is regulated by the reducer 232 and then transmitted to the heat pipe stirring shaft 21 via the sealed coupling 233, thereby driving the heat pipe stirring shaft 21 to rotate within the reaction chamber.

[0028] In this embodiment, the heat pipe stirring shaft 21 has a first internal cavity, and the heat pipe stirring paddle 22 has a second internal cavity. The second internal cavity is connected to the first internal cavity. A phase change working fluid is disposed in the first internal cavity and the second internal cavity, so that a continuous heat pipe cavity is formed inside the heat pipe stirring shaft 21 and the heat pipe stirring paddle 22.

[0029] During the manufacturing process, the first and second internal cavities can be evacuated first, and then a predetermined amount of phase change working fluid can be injected into them, so that the heat pipe stirring shaft 21 and the heat pipe stirring paddle 22 form an integrated heat pipe structure. The phase change working fluid can be selected according to the crystallization temperature of the mother liquor and the operating temperature range of the heat pipe. For example, for low-temperature crystallization processes with an operating temperature range of -20 to 50°C, ammonia or acetone can be used as the phase change working fluid; for medium-temperature crystallization processes with an operating temperature range of 50 to 150°C, water can be used; and for high-temperature crystallization processes with an operating temperature range of 150 to 250°C, naphthalene or biphenyl can be used. Optionally, a capillary reflux structure is provided in the first internal cavity. The capillary reflux structure is made of polytetrafluoroethylene mesh and extends along the first internal cavity to transport the condensed liquid phase change working fluid to the evaporation section by using capillary action.

[0030] Specifically, the portion of the heat pipe stirring paddle 22 located within the reaction chamber and immersed in the mother liquor constitutes the evaporation section, while the portion of the heat pipe stirring shaft 21 extending outside the vessel body 1 constitutes the condensation section. The evaporation section of the heat pipe stirring paddle 22 is in direct contact with the mother liquor. Heat from the mother liquor is transferred through the wall of the heat pipe stirring paddle 22 to the internal phase change working fluid, causing the phase change working fluid to absorb heat and vaporize, becoming a gaseous working fluid. The gaseous working fluid moves along the first internal cavity towards the condensation section, where it releases heat and condenses into a liquid working fluid. The liquid working fluid then returns to the evaporation section, thus forming a continuous phase change heat transfer cycle.

[0031] Specifically, the number of heat pipe impellers 22 is one or more. When the number of heat pipe impellers 22 is multiple, the multiple heat pipe impellers 22 are spaced apart along the axial direction of the heat pipe stirring shaft 21. One heat pipe impeller 22 includes: multiple heat pipe blades 221, and the multiple heat pipe blades 221 are spaced apart circumferentially along the heat pipe stirring shaft 21.

[0032] In one embodiment, the number of heat pipe stirring paddles 22 is 1 to 3, and each heat pipe stirring paddle 22 includes 2 to 6 heat pipe blades 221. The specific number of heat pipe stirring paddles 22 and heat pipe blades 221 can be selected according to the size of the vessel body 1, the viscosity of the mother liquor, and the required stirring intensity. The radial length L of the heat pipe blades 221 can be set to 0.3 to 0.6 times the inner diameter D of the vessel body 1. A gap δ is formed between the end of the heat pipe blade 221 and the inner wall of the vessel body 1. The gap δ can be controlled within the range of 20 to 80 mm, which allows the heat pipe blades 221 to cover a large radial range within the reaction chamber, enabling the mother liquor to fully contact the heat pipe blades 221 during stirring, thereby improving the heat extraction efficiency of the mother liquor. At the same time, by setting an appropriate gap between the end of the heat pipe blades 221 and the inner wall of the vessel body 1, this embodiment can reduce the possibility of interference between the heat pipe blades 221 and the inner wall of the vessel body 1.

[0033] For example, such as Figure 3 and Figure 4 As shown, there are two heat pipe stirring paddles 22, which are spaced apart along the axial direction of the heat pipe stirring shaft 21 and staggered. Specifically, each heat pipe stirring paddle 22 includes three heat pipe blades 221, which are evenly distributed circumferentially along the heat pipe stirring shaft 21 and arranged in a centrally symmetrical manner. The heat pipe blades 221 of two heat pipe stirring paddles 22 located at different axial positions are staggered in the circumferential direction, so that the heat pipe blades 221 of one heat pipe stirring paddle 22 do not overlap with the heat pipe blades 221 of the other heat pipe stirring paddle 22 in the circumferential direction. In this embodiment, through the above staggered arrangement, the heat pipe blades 22 at different axial positions generate disturbances to the mother liquor in different directions, expanding the disturbance range of the heat pipe blades 22 on the mother liquor in the reaction chamber.

[0034] Optionally, the heat pipe blades 221 can be inclined straight blades or spiral baffle blades. When spiral baffle blades are used, the heat pipe agitator 22 can generate both circumferential and axial flow during rotation, causing the mother liquor in the reaction chamber to circulate along the axial direction of the heat pipe agitator shaft 21, thereby enhancing the axial mixing effect inside the reaction chamber. For mother liquors with high viscosity, spiral baffle blades can enhance the overall circulation of the mother liquor and the contact between the mother liquor and the heat pipe agitator 22, which is beneficial to improving the heat transfer efficiency from the mother liquor to the heat pipe agitator assembly 2 and improving the temperature uniformity inside the reaction chamber.

[0035] In this embodiment, the heat pipe blade 221 is an inclined straight blade, and the heat pipe blade 221 is inclined towards the bottom of the vessel body 1. Specifically, the heat pipe blade 221 includes: a stirring element 2211 and a central tube 2212. The central tube 2212 passes through the interior of the stirring element 2211 and is connected to the first internal cavity of the heat pipe stirring shaft 21 to realize the flow of the phase change working fluid. Moreover, the end of the central tube 2212 passes through the stirring element 2211, so that the end of the central tube 2212 can directly contact the mother liquor to improve the heat exchange efficiency.

[0036] In this embodiment, the wall temperature control assembly includes a heating jacket 3. The heating jacket 3 is disposed on the outer wall of the vessel body 1, and has a first medium inlet 31 and a first medium outlet 32 ​​communicating with each other. The heating jacket 3 is used to contain the temperature control medium entering through the first medium inlet 31. The temperature control medium is used to exchange heat with the outer wall of the vessel body 1 to regulate the temperature of the inner wall of the vessel body 1.

[0037] Specifically, the heating jacket 3 can adopt a semi-tube jacket or a honeycomb jacket structure. The temperature control medium enters the heating jacket 3 through the first medium inlet 31 and flows along the interior of the heating jacket 3. After exchanging heat with the outer wall of the vessel body 1, it flows out through the first medium outlet 32. For example, the first medium inlet 31 is located at the lower part of the heating jacket 3, and the first medium outlet 32 ​​is located at the upper part of the heating jacket 3, so that the temperature control medium forms a bottom-in, top-out circulating flow path.

[0038] In one embodiment, the temperature of the temperature control medium is T3, satisfying T3 = T0 + N, where N is 5~30℃, to maintain the inner wall temperature of the vessel 1 above the crystallization temperature of the mother liquor. Optionally, the temperature control medium is hydrogenated terphenyl heat transfer oil, and the temperature of the hydrogenated terphenyl heat transfer oil is controlled at 250℃~350℃, with the specific temperature determined based on the crystallization temperature of the mother liquor and the required temperature to be maintained on the inner wall of the vessel 1. Optionally, when the crystallization temperature of the mother liquor is below 100℃, hot water can be used as the temperature control medium, exchanging heat with the outer wall of the vessel 1 to adjust the temperature of the inner wall of the vessel 1; alternatively, steam can be used as the temperature control medium, heating the outer wall of the vessel 1 by releasing latent heat through steam condensation. It should be noted that the temperature of the temperature control medium is not necessarily equal to the actual temperature of the inner wall of the vessel 1, as the actual inner wall temperature is also affected by factors such as the material of the vessel 1, wall thickness, jacket structure, and the heat exchange state of the mother liquor. Therefore, the temperature or flow rate of the heat transfer oil can be adjusted according to the actual detected inner wall temperature of the vessel 1, so that the temperature T2 of the second temperature zone is maintained within a range higher than the crystallization precipitation temperature T0.

[0039] In one embodiment, a first inlet temperature sensor 311 may be installed at the first medium inlet 31, and a first outlet temperature sensor 321 may be installed at the first medium outlet 32, so as to detect the temperature of the temperature control medium entering and flowing out of the heating jacket 3 respectively, and adjust the temperature and circulation state of the temperature control medium according to the detection results.

[0040] In this embodiment, the vessel body 1 includes a body 11 and a lid 12. One end of the body 11 has an opening. The lid 12 is detachably connected to the opening end of the body 11, and the lid 12 and the body 11 together form a reaction chamber. A heat pipe stirring assembly 2 passes through the lid 12. Specifically, as... Figure 5 As shown, the vessel cover 12 is provided with a central mounting hole 121, an instrument mounting port 124, a feed port 125, and a vent port 126. The central mounting hole 121 is used to install the heat pipe stirring assembly 2, and the instrument mounting port 124 is used to install the pressure sensor 7, which is used to detect the pressure state inside the reaction chamber. The feed port 125 is used to add mother liquor into the reaction chamber, and the vent port 126 is used to regulate the pressure inside the reaction chamber during feeding, crystallization, and discharge. The bottom of the body 11 is provided with a discharge port 111, and a bottom valve 112 is provided at the discharge port 111 to facilitate the discharge of crystal slurry after crystallization.

[0041] Specifically, the heat pipe stirring shaft 21 passes through the central mounting hole 121 into the vessel lid 12 and is rotatably connected to the vessel lid 12 via a positioning bearing 1211. The positioning bearing 1211 is used to radially position the heat pipe stirring shaft 21, allowing it to rotate relative to the vessel lid 12 around its own axis under the drive of the stirring drive 23, while limiting the radial offset of the heat pipe stirring shaft 21 relative to the vessel lid 12, thereby improving the stability of the heat pipe stirring shaft 21 during rotation. When maintenance is required, the stirring end of the heat pipe stirring assembly 2 can be cleaned by disassembling the vessel lid 12.

[0042] In this embodiment, the stirring end of the heat pipe stirring assembly 2 is the evaporation section, and the end of the heat pipe stirring assembly 2 away from the stirring end is the condensation section. The evaporation section is used to absorb heat from the mother liquor, and the condensation section is used to release heat. After absorbing heat from the mother liquor in the evaporation section, the phase change working fluid vaporizes and migrates along the inside of the heat pipe to the condensation section, where it releases heat and condenses into a liquid working fluid. Therefore, the condensation section continuously releases heat obtained from the mother liquor. To improve energy utilization, the crystallization reactor also includes a waste heat recovery assembly, which is located outside the condensation section and exchanges heat with the condensation section to absorb the heat released by the condensation section. Specifically, the waste heat recovery assembly is located in the area where the heat pipe stirring shaft 21 extends out of the reactor lid 12 and is coaxially arranged with the heat pipe stirring shaft 21. In this embodiment, the heat extracted from the mother liquor by the heat pipe stirring assembly 2 is further transferred to an external heat carrier through the waste heat recovery assembly, thereby preventing the heat released by the condensation section from being directly lost to the environment.

[0043] In this embodiment, the waste heat recovery assembly includes a water-cooled jacket 4. The water-cooled jacket 4 is fitted around the condensing section of the heat pipe stirring assembly 2. The water-cooled jacket 4 has a second medium inlet 41 and a second medium outlet 42. The water-cooled jacket 4 is used to contain the heat exchange medium entering through the second medium inlet 41. The heat exchange medium is used to exchange heat with the condensing section to absorb the heat released by the condensing section. Optionally, the second medium inlet 41 is located at the lower part of the water-cooled jacket 4, and the second medium outlet 42 is located at the upper part of the water-cooled jacket 4. The heat exchange medium enters the annular channel inside the water-cooled jacket 4 through the second medium inlet 41, exchanges heat with the condensing section, and is then discharged through the second medium outlet 42.

[0044] Optionally, the heat exchange medium can be cooling water, chilled brine, or ethylene glycol solution. When the crystallization process requires a lower condensation temperature, or when a large temperature difference needs to be maintained between the condensation section of the heat pipe stirring assembly 2 and the heat exchange medium, chilled brine or ethylene glycol solution can be used as the heat exchange medium.

[0045] In one embodiment, the heat exchange medium is cooling water, with the inlet water temperature controlled between 15°C and 30°C. After absorbing the heat released by the condensation section, the outlet water temperature can reach 40°C to 70°C. A second inlet temperature sensor 411 can be installed at the second medium inlet 41, and a second outlet temperature sensor 421 can be installed at the second medium outlet 42 to detect the temperature change of the cooling water before and after heat exchange. The high-temperature cooling water after heat exchange in the condensation section can be transported through pipelines to the preheating hot water storage tank in the plant area and used in other process steps that require heat energy, thereby realizing the recovery and utilization of waste heat from the heat pipe stirring assembly 2 and reducing energy loss during the crystallization process.

[0046] In this embodiment, the crystallization reactor further includes a temperature detection component. Specifically, the temperature detection component includes a first temperature sensor 5 and a second temperature sensor 6. The first temperature sensor 5 is disposed inside the reaction chamber and corresponds to a first temperature region, used to detect the temperature of the first temperature region. The second temperature sensor 6 is disposed on the inner wall side of the reactor body 1 and corresponds to a second temperature region, used to detect the temperature of the second temperature region.

[0047] In one embodiment, the vessel lid 12 is further provided with a central temperature measuring port 122 and an inner wall temperature measuring port 123. A first temperature sensor 5 extends into the reaction chamber through the central temperature measuring port 122 and extends its measuring end to a first temperature region to detect the temperature of the first temperature region. A second temperature sensor 6 extends into the reaction chamber through the inner wall temperature measuring port 123 and extends its measuring end to a second temperature region to detect the temperature of the second temperature region.

[0048] The crystallization reactor provided in this embodiment absorbs heat directly from the mother liquor through the heat pipe stirring assembly 2, creating a first temperature zone inside the mother liquor with a temperature lower than the crystallization precipitation temperature. Simultaneously, the temperature of the inner wall of the reactor 1 is adjusted by the wall temperature control assembly set on the outer wall of the reactor body 1, creating a second temperature zone inside the reactor body 1 with a temperature higher than the crystallization precipitation temperature. This can transfer the crystallization area from the vicinity of the traditional reactor wall heat exchange surface to the interior of the mother liquor, allowing the target solute to preferentially reach the crystallization precipitation conditions inside the mother liquor. At the same time, it inhibits the crystallization of the mother liquor near the inner wall of the reactor body 1, thereby reducing the adhesion and scaling of crystals on the inner wall of the reactor body 1. This reduces problems such as decreased heat exchange performance, reduced effective volume, and frequent shutdowns for cleaning caused by reactor wall crystallization, and improves the continuous operation capability of the crystallization reaction.

[0049] The second aspect of this embodiment provides a crystallization control method, applied to the crystallization reactor provided in the first aspect of this application. Please refer to [link to relevant documentation]. Figure 6 , Figure 6 A flowchart illustrating the steps of a crystallization control method according to an embodiment of this application is shown. The crystallization control method provided in this embodiment includes the following steps: S1: Add the mother liquor into the reaction chamber.

[0050] Specifically, a predetermined amount of mother liquor is added to the reaction chamber. The mother liquor can be a supersaturated or nearly saturated solution containing the target solute, and the corresponding crystallization temperature T0 is determined according to the specific type of solute.

[0051] S2: The mother liquor is stirred by the stirring end of the heat pipe stirring assembly, and the heat in the mother liquor is absorbed to form a first temperature zone in the reaction chamber.

[0052] Specifically, the stirring drive is activated, causing the heat pipe stirring shaft to rotate the heat pipe stirring paddle. The heat pipe stirring paddle stirs the mother liquor, creating a circulating flow within the reaction chamber. Simultaneously, the heat pipe stirring paddle acts as the evaporation section of the heat pipe, absorbing heat from the mother liquor. The heat from the mother liquor is transferred to the phase change working fluid inside the heat pipe, causing it to vaporize. The gaseous working fluid moves along the inside of the heat pipe towards the condensation section, where it releases heat and condenses. The condensed liquid working fluid returns to the evaporation section, thus continuously extracting heat from the mother liquor.

[0053] S3: Adjust the temperature of the inner wall of the vessel by means of the wall temperature control component, so that the inner wall of the vessel forms a second temperature zone.

[0054] Specifically, while starting the stirring drive, a temperature-controlled medium is introduced into the heating jacket. The temperature-controlled medium exchanges heat with the outer wall of the vessel, regulating the temperature of the inner wall of the vessel and creating a second temperature zone on the inner wall.

[0055] S4: Obtain the temperature T1 of the first temperature region, the temperature T2 of the second temperature region, and the crystallization temperature T0 of the mother liquor, and control the temperatures of the first temperature region and the second temperature region to satisfy T2 > T0 > T1, so that the first temperature region reaches the crystallization condition of the mother liquor and inhibits the crystallization of the mother liquor in the second temperature region.

[0056] Specifically, the temperature T1 of the first temperature region is detected by a first temperature sensor, the temperature T2 of the second temperature region is detected by a second temperature sensor, and the crystallization temperature T0 of the mother liquor is obtained. Based on the detection results, the heat pipe stirring assembly and the wall temperature control assembly are adjusted to ensure that T2 > T0 > T1.

[0057] Furthermore, when T1 is higher than the preset target value, the heat extraction capacity of the heat pipe stirring assembly can be improved, for example, by adjusting the stirring operation parameters or the heat exchange conditions of the condensing section, so that the heat extracted by the heat pipe stirring assembly from the mother liquor can be increased. When T2≤T0, the temperature of the temperature control medium can be increased or the flow rate of the temperature control medium can be adjusted to raise the temperature of the inner wall of the reactor.

[0058] The crystallization control method provided in this embodiment controls the temperatures of a first temperature region and a second temperature region, ensuring that the first temperature region remains under the conditions for crystallization and precipitation of the mother liquor, while the second temperature region is maintained above the crystallization and precipitation temperature. Therefore, the target solute mainly crystallizes and grows within the mother liquor, while the crystallization driving force is suppressed in the region adjacent to the inner wall of the reactor due to the maintained higher temperature, thereby reducing the possibility of crystal nucleation, adhesion, and gradual formation of crystal scars on the inner wall of the reactor.

[0059] The crystallization reactor provided in this embodiment directly absorbs heat from the mother liquor by placing the stirring end of the heat pipe stirring assembly inside the mother liquor. The temperature of the inner wall of the reactor is regulated by the wall temperature control assembly, establishing a first temperature zone and a second temperature zone within the reaction chamber. The temperature of the first temperature zone T1, the temperature of the second temperature zone T2, and the crystallization temperature T0 of the mother liquor satisfy the condition T2 > T0 > T1. This satisfies the crystallization conditions inside the mother liquor while reducing the crystallization tendency at the inner wall of the reactor. At the same time, the heat pipe stirring assembly can transfer the heat of the mother liquor to the outside of the reactor, and the heat released in the condensation section can be recovered by the waste heat recovery assembly, thereby improving energy utilization efficiency.

[0060] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0061] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A crystallization reactor, characterized in that, include: The vessel body has a reaction chamber for containing the mother liquor; A heat pipe stirring assembly, wherein the stirring end of the heat pipe stirring assembly is disposed in the reaction chamber, and the stirring end of the heat pipe stirring assembly is used to stir the mother liquor and absorb heat from the mother liquor, so as to form a first temperature zone in the reaction chamber; A wall temperature control component is disposed on the outer wall of the vessel body to adjust the temperature of the inner wall of the vessel body so that the inner wall of the vessel body forms a second temperature zone; the temperature of the first temperature zone is T1, the temperature of the second temperature zone is T2, and the crystallization temperature of the mother liquor is T0, satisfying that T2 > T0 > T1.

2. The crystallization reactor according to claim 1, characterized in that, The heat pipe stirring assembly includes: A heat pipe stirring shaft is partially disposed in the reaction chamber; A heat pipe stirring paddle is connected to the heat pipe stirring shaft and disposed in the reaction chamber, the heat pipe stirring paddle forming the stirring end; A stirring drive unit is connected to the heat pipe stirring shaft. The stirring drive unit is used to drive the heat pipe stirring shaft to rotate, thereby driving the heat pipe stirring paddle to rotate in the reaction chamber.

3. The crystallization reactor according to claim 2, characterized in that, The heat pipe stirring shaft has a first internal cavity; The heat pipe stirring paddle has a second internal cavity; The second internal cavity is connected to the first internal cavity, and both the first and second internal cavities contain a phase change working fluid.

4. The crystallization reactor according to claim 2, characterized in that, The number of heat pipe stirring blades is multiple, and the multiple heat pipe stirring blades are spaced apart along the axial direction of the heat pipe stirring shaft; A heat pipe impeller includes a plurality of heat pipe blades, the plurality of heat pipe blades being arranged circumferentially spaced along the heat pipe stirring axis.

5. The crystallization reactor according to any one of claims 1 to 4, characterized in that, The wall temperature control component includes: A heating jacket is disposed on the outer wall of the vessel body. The heating jacket has a first medium inlet and a first medium outlet that are connected. The heating jacket is used to contain the temperature control medium entering through the first medium inlet. The temperature control medium is used to exchange heat with the outer wall of the vessel body to regulate the temperature of the inner wall of the vessel body.

6. The crystallization reactor according to claim 5, characterized in that, The vessel body includes: The body has an opening at one end; The vessel lid is detachably connected to the open end of the body, and the vessel lid and the body enclose the reaction chamber. The heat pipe stirring assembly passes through the vessel lid.

7. The crystallization reactor according to any one of claims 1 to 4, characterized in that, The stirring end of the heat pipe stirring assembly is an evaporation section, and the end of the heat pipe stirring assembly away from the stirring end is a condensation section. The evaporation section is used to absorb heat from the mother liquor, and the condensation section is used to release the heat. The crystallization reactor also includes: A waste heat recovery component is disposed on the outside of the condensing section and exchanges heat with the condensing section to absorb the heat released by the condensing section.

8. The crystallization reactor according to claim 7, characterized in that, The waste heat recovery component includes: A water-cooled jacket is fitted over the outside of the condensation section of the heat pipe stirring assembly. The water-cooled jacket has a second medium inlet and a second medium outlet. The water-cooled jacket is used to contain the heat exchange medium entering through the second medium inlet. The heat exchange medium is used to exchange heat with the condensation section to absorb the heat released by the condensation section.

9. The crystallization reactor according to any one of claims 1 to 4, characterized in that, The crystallization reactor also includes: The temperature detection component includes: a first temperature sensor and a second temperature sensor; The first temperature sensor is disposed inside the reaction chamber and corresponds to the first temperature region, and is used to detect the temperature of the first temperature region. The second temperature sensor is disposed on the inner wall side of the vessel and corresponds to the second temperature region, and is used to detect the temperature of the second temperature region.

10. A method for controlling crystallization, characterized in that, The crystallization reactor used in any one of claims 1 to 9 comprises: Add the mother liquor into the reaction chamber; The mother liquor is stirred by the stirring end of the heat pipe stirring assembly, and the heat in the mother liquor is absorbed to form a first temperature zone in the reaction chamber. The temperature of the inner wall of the vessel is adjusted by the wall temperature control component so that the inner wall of the vessel forms a second temperature zone. The temperature T1 of the first temperature region, the temperature T2 of the second temperature region, and the crystallization temperature T0 of the mother liquor are obtained, and the temperatures of the first temperature region and the second temperature region are controlled to satisfy T2 > T0 > T1, so that the first temperature region reaches the crystallization condition of the mother liquor and the crystallization of the mother liquor in the second temperature region is inhibited.

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