Crystallization kettle for crystallizing asparaginic acid
By designing segmented heating modules, variable-diameter spiral half-pipe jackets, and double-layer stirring paddles, combined with a biomimetic composite heat transfer layer, the problems of large temperature gradients and uneven stirring in the aspartic acid crystallization kettle were solved, achieving uniform crystal particle size and improved production efficiency.
Patent Information
- Application Number
- CN202520410298.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2035-03-11
AI Technical Summary
Existing aspartic acid crystallization kettles suffer from problems such as large axial temperature gradient, uneven stirring, and low temperature control accuracy, resulting in discrete crystal particle size distribution, long production cycle, and poor batch stability of products.
The design employs a segmented heating module, a variable-diameter spiral half-pipe jacket, a double-layer stirring paddle, and a biomimetic composite heat transfer layer. Combined with precise temperature control and a stirring device, a temperature gradient is formed to promote uniform crystallization of the solute and prevent non-uniform crystal growth.
It significantly improves crystal size uniformity, shortens production cycle, reduces energy consumption, and enhances product batch stability and production efficiency.
Smart Images
Figure CN223846273U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the field of industrial crystallization equipment, in particular to a crystallization kettle for aspartic acid crystallization. BACKGROUND
[0002] As an important pharmaceutical intermediate and food additive, the crystallization process of aspartic acid is highly sensitive to the precision, uniformity and energy consumption of temperature control. The traditional crystallization kettle heating system widely used in the current industrial field is mainly based on the combination structure of steam jacket and built-in coil, which realizes heat conduction by providing saturated steam from an external boiler and realizes material mixing by mechanical stirring. Although such system has the advantages of mature process and low equipment cost, it has significant defects in actual operation. First, the steam flow path design of the traditional jacket is single, the heat transfer area is limited and the flow velocity distribution is uneven, which leads to an axial temperature gradient of 3-5 DEG C in the kettle, especially in the late crystallization stage, the local supercooling phenomenon frequently occurs due to the increase of solution viscosity and thermal resistance, which directly causes the dispersion of crystal particle size distribution (coefficient of variation CV>30%), which seriously affects the batch stability of the product. Secondly, the existing stirring system mostly uses fixed speed anchor paddle, which can realize basic mixing, but it is difficult to effectively break the temperature boundary layer, and the temperature difference between the center and the edge of the kettle body aggravates the non-uniform growth of the crystal nucleus, and the stirring paddle itself lacks auxiliary heat transfer function, which causes the insufficient heating rate (usually <1.5 DEG C / min) in the dissolution stage, prolonging the production cycle. In addition, the traditional temperature control mode relies on single temperature probe feedback PID regulation, and the low control precision of the super-saturation degree caused by the lagging response characteristics often needs to add excessive seed to compensate, which increases the loss of raw materials and introduces impurity risk. CONTENT OF THE UTILITY MODEL
[0003] The purpose of the present application is to at least overcome one of the deficiencies in the prior art, and provide a crystallization kettle for aspartic acid crystallization.
[0004] To achieve the above purpose, the present application discloses a crystallization kettle for aspartic acid crystallization, which comprises a kettle body and a stirring device located inside the kettle body.
[0005] Among them, the outer wall of the kettle body is covered with three heating modules, which are divided into upper segment heating module, middle segment heating module and lower segment heating module along the axial direction, each heating module is a variable-diameter spiral half-pipe jacket, the variable-diameter spiral half-pipe jacket and the outer wall of the kettle body form a closed heat exchange flow channel, and the heat exchange flow channels of each heating module are connected to independent heat source supply pipelines through flange interfaces, and electromagnetic proportional valves and temperature sensors are arranged on the pipelines for accurately controlling and monitoring the heating temperature and heat source flow of each segment.
[0006] The stirring device includes a main shaft and a double-layer stirring impeller. The main shaft has a hollow shaft structure with internal heat transfer oil channels. Spiral fins are welded to the outer surface of the shaft, with a height between 2mm and 4mm and an angle of 30° with the axis. The double-layer stirring impeller consists of an upper inclined blade turbine impeller and a lower anchor impeller. The blade inclination angle of the inclined blade turbine impeller is 45±2°. The gap between the outer edge of the blade of the anchor impeller and the inner wall of the vessel is between 5mm and 8mm. The impeller blade surface is provided with hemispherical turbulence protrusions with a height of 4mm to 6mm and arranged in an array at intervals of 15mm to 20mm. The bottom end of the main shaft forms a closed loop with an external high-temperature oil pump through a rotary joint.
[0007] Furthermore, the anchor propeller has hemispherical turbulence protrusions on its blade surface.
[0008] Furthermore, a biomimetic composite heat transfer layer is provided on the inner wall of the reactor. This heat transfer layer is composed of a microgroove substrate and a hydrophobic coating. The microgroove substrate forms V-shaped continuous grooves on the inner wall of the reactor through laser etching. The groove depth is 40μm to 60μm, the groove width is 150μm to 250μm, and the center-to-center distance between adjacent grooves is 1.2 to 1.5 times the groove width. This microgroove structure can effectively promote the flow of liquid and the transfer of heat, and enhance the uniformity of the crystallization process. The hydrophobic coating has a thickness of 200nm to 300nm and a surface roughness Ra of 0.8μm to 1.2μm. This hydrophobic coating can not only effectively prevent the adhesion and scaling of materials on the inner wall of the reactor, but also significantly reduce the contact thermal resistance between the liquid and solid surfaces, and improve the heat transfer efficiency.
[0009] Compared with existing technologies, this application improves the precision of temperature control and the uniformity of crystallization. The synergistic effect of segmented gradient heating and biomimetic enhanced heat transfer significantly reduces the temperature difference inside the reactor, suppresses non-uniform crystal growth, and greatly improves the uniformity of crystal size.
[0010] The beneficial effects listed above are not exhaustive of all advantages. Other potential beneficial effects and detailed technical implementation methods will be further disclosed in the embodiments or other descriptive sections of this application. Attached Figure Description
[0011] A better understanding of various aspects of this disclosure will be achieved by reading the following detailed description in conjunction with the accompanying drawings. The positions, dimensions, and extents of the structures shown in the drawings, etc., do not always represent actual positions, dimensions, and extents. In the drawings:
[0012] Figure 1 This is a schematic diagram of the structure of one embodiment disclosed in this application.
[0013] Figure 2 This is a partial cross-sectional structural diagram of the inner wall of the crystallization vessel in one embodiment of this application. Detailed Implementation
[0014] The present disclosure will be described with reference to the accompanying drawings, which show several embodiments of the present disclosure. It is understood that the present disclosure can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and fully convey the scope of protection of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.
[0015] It should be understood that in all the drawings, the same reference signs represent the same elements. In the drawings, the size of some features can be distorted for the sake of clarity.
[0016] It should be understood that the language used in the specification is only for describing specific embodiments and is not intended to limit the present disclosure. Unless otherwise defined, all terms (including technical and scientific terms) used in the specification have the meanings commonly understood by those skilled in the art. For the sake of brevity and / or clarity, techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the authorized description when appropriate.
[0017] The singular forms "a", "said" and "the" used in the specification, unless clearly indicated otherwise, include plural forms. The language "includes", "comprises" and "contains" used in the specification means the presence of the stated feature, but does not exclude the presence of one or more other features. The language "and / or" used in the specification includes any and all combinations of one or more of the associated listed items.
[0018] The following is an example of a crystallization kettle for crystallizing aspartic acid
[0019] Referring to the accompanying drawings Figure 1 and 2 In this embodiment, a crystallization kettle for crystallizing aspartic acid is described in detail, which is designed and functions to optimize the crystallization process of aspartic acid, improve the quality and yield of crystals. The key components of the crystallization kettle include the kettle body and the stirring device, the interaction and independent functions of these components together promote an efficient crystallization environment.
[0020] The kettle body 1 is the basis of the entire crystallization system, and the selection of its structure and material is crucial to the performance of the entire device. In this embodiment, the kettle body 1 is made of 316L stainless steel, which is widely used in the chemical and pharmaceutical fields due to its excellent corrosion resistance and mechanical strength, which can ensure that the kettle body 1 will not be damaged due to contact with corrosive substances during the crystallization process of aspartic acid, thereby prolonging the service life of the equipment and ensuring the safety of production.
[0021] The kettle body 1 is externally designed with three heating modules 2, 3, 4, which are upper heating module 2, middle heating module 3, and lower heating module 4, respectively, located in the upper, middle, and lower sections of the kettle body 1. This segmented heating design is based on the thermodynamic principle in the crystallization process, by providing different heating temperatures at different heights, a temperature gradient can be formed inside the kettle body 1, thereby promoting the gradual crystallization of solutes.
[0022] Specifically, the temperature of the upper heating module 2 is precisely controlled at 90±2℃, the temperature of the middle heating module 3 is controlled at 70±1℃, and the temperature of the lower heating module 4 is maintained at 50±1℃. This temperature setting takes into account the solubility change of aspartic acid at different temperatures, so that the solute can gradually precipitate crystals under suitable temperature conditions.
[0023] Each heating module 2, 3, 4 adopts a variable-diameter spiral half-pipe jacket structure, which not only maximizes the use of the outer wall space of the kettle, improving heat exchange efficiency, but also better adapts to the heating needs of different sections through variable-diameter design, achieving more precise temperature control. The variable-diameter spiral half-pipe jacket 5 forms a closed heat exchange channel 6 with the outer wall of the kettle 1, which is connected to an independent heat source supply pipeline through a flange interface. The electromagnetic proportional valve and temperature sensor (not shown in the figure) set on the pipeline can automatically adjust the heat source flow according to the preset temperature parameters, ensuring that the temperature of each heating module remains within the optimal range.
[0024] It should be noted that the specific selection of electromagnetic proportional valve and temperature sensor and the design of their control circuit belong to the common technical knowledge of those skilled in the art, which will not be described here.
[0025] The stirring device 7 plays a crucial role in the crystallization process, not only promoting uniform mixing of the solution, ensuring uniform distribution of solutes in the kettle, but also enhancing heat transfer, maintaining the thermodynamic balance of the entire system.
[0026] The stirring device 7 in this embodiment consists of a main shaft 701 and a double-layer stirring paddle, both of which are designed and optimized for the characteristics of aspartic acid crystallization.
[0027] The main shaft 701 adopts a hollow shaft structure with a heat conducting oil channel inside. This design allows the heat conducting oil to circulate inside the main shaft 701, thereby uniformly heating the solution during stirring. The main shaft 701 is made of 304 stainless steel, which not only ensures mechanical strength but also has good corrosion resistance, suitable for the chemical environment in the crystallization process.
[0028] The outer surface of the shaft body 701 is welded with spiral fins (not shown in the figure), the fin height is 3mm, and the fins are distributed at an angle of 30° with the axis. The design of the spiral fin aims to enhance the heat exchange efficiency between the heat conducting oil and the solution, while producing a certain pushing effect on the solution during stirring, promoting the circulation of the solution, and further improving the heat and mass transfer efficiency.
[0029] The double-layer stirring paddle includes the upper inclined-blade turbine paddle 702 and the lower anchor paddle 703. The blade angle of the upper inclined-blade turbine paddle 702 is 45°, which can produce strong shear force on the solution during stirring, making the solution form a circulating flow in the horizontal and vertical directions, thereby promoting the uniform distribution of solutes and heat transfer.
[0030] The outer edge of the paddle blade of the lower anchor paddle 703 maintains a gap of 6mm with the inner wall of the kettle body, which can ensure sufficient stirring of the solution at the bottom of the kettle body 1, and avoid friction and wear caused by too small gap. The paddle blade surface is provided with semispherical turbulence protrusions, the protrusion height is 5mm, and the protrusions are arranged in an array with a spacing of 18mm (in the figure, the above-mentioned proportion data is not drawn for convenience). These turbulence protrusions can effectively destroy the stagnant flow boundary layer of the liquid layer, enhance the turbulence degree of the liquid, further improve the heat and mass transfer efficiency, and prevent the adhesion and aggregation of crystals on the paddle blade surface.
[0031] The bottom end of the main shaft 701 is connected with the external high-temperature oil pump through a rotary joint to form a closed loop, and the rotary joint adopts a mechanical seal structure to ensure that the heat conducting oil does not leak during rotation. The high-temperature oil pump delivers the heat conducting oil to the inside of the main shaft, and after heat exchange, the heat conducting oil returns to the oil pump to form a closed loop circulation system. It should be noted that the specific selection of the high-temperature oil pump and the connection mode with the rotary joint belong to the known technology of those skilled in the art, which will not be disclosed in detail here.
[0032] The bionic composite heat transfer layer provided on the inner wall of the kettle body 1 is an innovation point in this embodiment, and the design inspiration comes from the efficient heat transfer structure in nature. The heat transfer layer is composed of a micro-groove base and a hydrophobic nano-coating layer, which aims to optimize the heat and mass transfer process through microstructure and material properties, while preventing the adhesion and fouling of materials on the inner wall of the kettle body.
[0033] The micro-groove base forms a V-shaped continuous groove on the inner wall of the kettle body by laser etching, the groove depth is 50μm, the groove width is 200μm, and the center distance between adjacent grooves is 1.3 times the groove width. The design of this microstructure is based on the principles of fluid mechanics and heat conduction, which can effectively promote the flow and heat transfer of the liquid in the groove. The geometric shape of the V-shaped groove helps to guide the flow direction of the liquid, increases the contact area between the liquid and the groove wall, and thus improves the heat transfer efficiency. At the same time, this microstructure can also disturb the laminar boundary layer of the fluid to some extent, increase the turbulence degree of the fluid, and further enhance the heat and mass transfer effect.
[0034] The hydrophobic nano-coating is a SiO2 / TiO2 composite coating with a thickness of 250 nm and a surface roughness Ra of 1.0 μm. The main function of the composite coating is to reduce the contact thermal resistance between the liquid and the solid surface and improve the heat transfer efficiency. The SiO2 / TiO2 composite material has excellent hydrophobic properties and thermal stability, and can form a stable hydrophobic film on the inner wall of the kettle 1 to prevent the adhesion and fouling of the material on the inner wall. In addition, the microstructure with a surface roughness Ra of 1.0 μm can provide more free space for liquid flow, reduce the residence time of the fluid on the inner wall, and further improve the heat transfer efficiency. It should be noted that the specific parameter control of the laser etching process and the operation of the equipment belong to the common technical knowledge of those skilled in the art, which will not be described here.
[0035] In actual operation, first, aspartic acid solution is added to the crystallization kettle through the feed inlet. Start the external high-temperature oil pump, and the heat conduction oil enters the crystallization kettle through the heat conduction oil channel inside the main shaft 701 to preheat the solution. At the same time, the heat source supply pipeline introduces heat medium into the heat exchange flow channel 6 of each heating module, and the heating temperature and heat source flow of each section are accurately controlled and monitored through electromagnetic proportional valves and temperature sensors to realize the segmented heating of the solution in the crystallization kettle, promote the uniform heating of the solution and the dissolution of the solute.
[0036] Next, start the stirring device 7, and the main shaft drives the double-layer stirring paddle to rotate. The upper layer of the inclined blade turbine paddle 702 is inclined at an angle of 45° to the blade to perform strong shearing and mixing on the solution, so that the solution forms a circulating flow in the horizontal and vertical directions, promoting the uniform distribution of the solute and the heat transfer. The lower layer of the anchor paddle 703 slowly stirs the bottom solution at a lower speed, and the semispherical turbulence protrusions on its surface can effectively destroy the stagnant boundary layer of the liquid layer, enhance the degree of turbulence of the liquid, further improve the heat and mass transfer efficiency, and at the same time avoid the aggregation and caking of the crystals at the bottom of the kettle.
[0037] During the crystallization process, the micro-groove base of the bionic composite heat transfer layer promotes the flow and heat transfer of the liquid on the inner wall of the kettle through the V-shaped continuous groove structure, and enhances the uniformity of the crystallization process. The hydrophobic nano-coating effectively prevents the adhesion and fouling of the material on the inner wall of the kettle, reduces the contact thermal resistance between the liquid and the solid surface, and improves the heat transfer efficiency. At the same time, the roughness of its surface can provide more free space for liquid flow, reduce the residence time of the fluid on the inner wall, and further improve the heat transfer efficiency.
[0038] The crystallization kettle for aspartic acid crystallization described in this embodiment can realize efficient crystallization of aspartic acid solution and improve the quality and yield of the crystals through the reasonable design and optimized configuration of each component. The main technical advantages include:
[0039] 1. The design of the segmented heating module can form a temperature gradient, promote the gradual crystallization of solutes, and improve the crystallization efficiency.
[0040] 2. The double-layer stirring paddle design of the stirring device 7 can achieve uniform mixing of the solution and heat transfer, avoiding crystal aggregation and caking.
[0041] 3. The micro-groove structure and hydrophobic nano-coating of the biomimetic composite heat transfer layer can significantly improve the heat transfer efficiency, prevent material adhesion and fouling, and reduce maintenance costs.
[0042] 4. The entire system can realize stable crystallization process through precise temperature control and efficient stirring mechanism, improving production efficiency and product quality.
[0043] In summary, the crystallization kettle described in this embodiment has good application prospects and can meet the demand for aspartic acid crystallization in large-scale industrial production, providing strong support for production and technological development in related fields.
[0044] Although exemplary embodiments of the present disclosure have been described, those skilled in the art will understand that various changes and modifications can be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure in essence. Therefore, all changes and modifications are included in the protection scope of the present disclosure defined by the claims. The present disclosure is defined by the additional claims, and the equivalents of these claims are also included.
Claims
1. A crystallization tank for crystallization of aspartic acid, characterized in that, The crystallization kettle comprises a kettle body and a stirring device arranged inside the kettle body; The outer wall of the kettle body is coated with three heating modules, which are divided into an upper segment heating module, a middle segment heating module and a lower segment heating module along the axial direction, each of the heating modules is a variable-diameter spiral half-pipe jacket, the variable-diameter spiral half-pipe jacket and the outer wall of the kettle body form a closed heat exchange flow channel, the heat exchange flow channels of the heating modules are respectively connected to independent heat source supply pipelines through flange interfaces, and electromagnetic proportional valves and temperature sensors are arranged on the pipelines for accurately controlling and monitoring the heating temperature and the heat source flow of each segment; The stirring device comprises a main shaft and double-layer stirring paddles, the main shaft adopts a hollow shaft structure, a heat conduction oil channel is arranged in the main shaft, and helical fins are welded to the outer surface of the shaft body, the fins have a height of 2mm to 4mm and are distributed at an angle of 30° with the axis, the double-layer stirring paddles comprise upper inclined-blade turbine paddles and lower anchor paddles, the blade of the inclined-blade turbine paddle has an inclination angle of 45±2°, the gap between the outer edge of the paddle blade of the anchor paddle and the inner wall of the kettle body is 5mm to 8mm, a semispherical turbulence protrusion is arranged on the surface of the paddle blade, the protrusion has a height of 4mm to 6mm and is arranged in an array with a spacing of 15mm to 20mm, and the bottom end of the main shaft is connected to an external high-temperature oil pump through a rotary joint to form a closed loop.
2. The crystallizer for crystallization of aspartic acid according to claim 1, characterized in that, The semispherical turbulence protrusion arranged on the surface of the paddle blade of the anchor paddle.
3. The crystallizer for crystallization of aspartic acid as claimed in claim 1, wherein The inner wall of the kettle body is provided with a bionic composite heat transfer layer, which is composed of a micro-groove base and a hydrophobic plating layer, the micro-groove base forms a V-shaped continuous groove on the inner wall of the kettle body through laser etching, the groove depth is 40μm to 60μm, the groove width is 150μm to 250μm, and the center distance between adjacent grooves is 1.2 to 1.5 times the groove width, the micro-groove structure can effectively promote the flow of liquid and the transfer of heat and enhance the uniformity of the crystallization process; the hydrophobic plating layer has a thickness of 200nm to 300nm and a surface roughness Ra of 0.8μm to 1.2μm.