Crystallization system and crystallization method

Abstract

To provide a crystallization system and a crystallization method where fine particles crystallized in a crystallizer can be stayed without requiring a residence tank.SOLUTION: A crystallization system 10A comprises: a crystallizer 4 where a plurality of raw material solutions is mixed and particles derived from raw materials in the plurality of raw material solutions are generated; a circulation pipeline Po where slurry D1 containing the particles discharged from the discharge port 6 of the crystallizer 4 is fluidized and the slurry D1 is circulated from the introduction port 5a of the crystallizer 4 into the crystallizer 4; and a circulation pump 30 to circulate the slurry D1 between the crystallizer 4 and the circulation pipeline Po. The circulation pipeline Po has a bent part Pp having a meandering shape.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a crystallization system and a crystallization method. [Background technology]

[0002] The crystallizers described in Patent Documents 1 to 4 are known as crystallizers that mix a plurality of raw material solutions and obtain particles derived from the raw materials in the raw material solutions within a certain particle size range.

[0003] In the crystallization apparatus described above, stirring blades installed in a mixture of multiple raw solution materials are rotated to apply shear force to the mixture, thereby promoting stirring. To produce high-quality microparticles with a more uniform particle size, it is important to efficiently transmit the generated shear force generated by rotating the stirring blades at high speed to the reaction field, where the multiple raw solution materials come into contact with each other and a reaction takes place to produce particles, thereby promoting the reaction. To achieve efficient transmission of shear force, attempts have been made to minimize the clearance between the stirring blades (rotors) and the reaction vessel or reaction solution supply nozzle (stators). In the crystallizer described above, as described in Non-Patent Document 1, a retention tank is provided, and the fine particles crystallized in the crystallizer are retained in the retention tank, thereby ensuring the retention time required for the crystals to grow to a particle size within a certain range.

[0004] However, when a retention tank is used, it is necessary to adjust the retention time in the retention tank by adjusting the liquid level in the retention tank. However, adjusting the liquid level in the retention tank changes the flow state within the retention tank, which requires complex flow analysis, making it difficult to control particle size and increasing the cost of the crystallizer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-137183 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-022894 [Patent Document 3] Patent No. 3256801 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-87590 [Non-patent literature]

[0006] [Non-Patent Document 1] Kobe, "New Developments in Vortex-Type Fine Particle Crystallizers," TSK Technical Report, Tsukishima Kikai Co., Ltd., December 2020, No. 23, pp. 30-32 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made under such circumstances, and an object of the present invention is to provide a crystallization system and a crystallization method that do not require a retention tank, can retain fine particles precipitated in a crystallizer until they grow to a certain particle size range, and can easily control the retention conditions. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention comprises the following means. A first aspect of the present invention is a crystallization system comprising: a crystallizer that mixes a plurality of raw material solutions to produce particles derived from the raw materials in the plurality of raw material solutions; a circulation pipeline that flows a slurry containing the particles discharged from an outlet of the crystallizer and circulates the slurry from an inlet of the crystallizer into the crystallizer; and a circulation pump that circulates the slurry between the crystallizer and the circulation pipeline, wherein the circulation pipeline has a serpentine bend.

[0009] According to the first aspect of the present invention, the slurry discharged from the crystallizer flows through the circulation pipeline at a flow rate corresponding to the flow rate, and therefore the slurry in the crystallization system can be easily and completely mixed uniformly by controlling the flow rate of the circulation pump without the need for complex flow analysis.

[0010] A second aspect of the present invention is characterized in that in the first aspect, the inner diameter of the circulation pipe is constant.

[0011] According to the second aspect of the present invention, the slurry discharged from the crystallizer flows through a circulation pipe with a constant inner diameter, and therefore the slurry in the crystallization system can be easily and completely mixed uniformly by controlling the flow rate of the circulation pump without requiring complex flow analysis.

[0012] A third aspect of the present invention is characterized in that in the first aspect, a plurality of the bent portions are provided.

[0013] According to the third aspect of the present invention, since a plurality of bent portions are provided, even when the volume of slurry is large, the slurry in the crystallization system can be easily mixed completely and uniformly by controlling the flow rate of the circulation pump without the need for complex flow analysis.

[0014] A fourth aspect of the present invention is characterized in that in the first aspect, at least a part of the bent portion is provided inside a temperature-controlled bath.

[0015] According to the fourth aspect of the present invention, at least a part of the bent portion is provided inside the temperature control tank. Therefore, by controlling the flow rate of the circulation pump, the slurry in the crystallization system can be easily mixed uniformly and the calorific value of the slurry can be easily adjusted.

[0016] A fifth aspect of the present invention is characterized in that, in the first aspect, the bending portion is made up of a plurality of separable straight pipe portions and a plurality of separable curved pipe portions.

[0017] According to the fifth aspect of the present invention, the flow path length of the bent section can be adjusted by changing the number of the plurality of straight pipe sections and the plurality of curved pipe sections, so that the residence time of the slurry can be adjusted by adjusting the flow path length of the bent section without requiring complex flow analysis.

[0018] A sixth aspect of the present invention is the crystallization apparatus of the first aspect, characterized in that it comprises an agitator blade having a plurality of holes penetrating in the radial direction and rotatable around a central axis, a cylindrical reaction tank with a bottom that can concentrically accommodate the agitator blade therein, the inlet that is provided in the reaction tank and can supply a first reaction liquid into the reaction tank, and a liquid supply unit that is provided in the agitator blade and can supply a second reaction liquid into the reaction tank.

[0019] According to the sixth aspect of the present invention, the second reaction liquid is supplied from a liquid supply section provided in the stirring impeller, and therefore high manufacturing precision is not required as in the case where the reaction liquid supply nozzle and the stirring impeller are provided separately. The second reaction liquid can be supplied within a close range, for example, within 2 mm, from the inner and outer peripheries of the stirring impeller where the shearing force is highest. Furthermore, because the stirring impeller has multiple holes penetrating in the radial direction, the mixture of the first and second reaction liquids passes through the holes radially outward of the stirring impeller under the influence of centrifugal force and reacts while moving toward the outer periphery of the stirring impeller. This further promotes stirring of the mixture within a close range, for example, within 2 mm, from the inner and outer peripheries of the stirring impeller where the shearing force is highest.

[0020] A seventh aspect of the present invention is characterized in that, in the fifth aspect, the stirring impeller comprises a cylindrical portion, a disk-shaped disk portion whose outer edge is fixed to the inner surface of the cylindrical portion, and a rotating shaft extending upward from the center of the disk portion along the central axis in a planar view, the second reaction liquid can flow through the inside of the disk portion and the rotating shaft, and the liquid supply section is provided on the outer edge of the disk portion.

[0021] According to the seventh aspect of the present invention, since the liquid supply section is provided on the outer edge of the disk section, the second reaction liquid can be supplied within a close range, for example, within 2 mm, from the inner and outer peripheries of the stirring blades where the shear force is the highest.

[0022] An eighth aspect of the present invention is characterized in that, in the sixth aspect, the liquid supply section opens downward.

[0023] According to the eighth aspect of the present invention, the liquid supply section opens downward, so that the second reaction liquid can be supplied within a close range, for example, within 2 mm, from the inner and outer peripheries of the stirring blades where the shear force is the highest.

[0024] A ninth aspect of the present invention is the sixth aspect, characterized in that the liquid supply portion opens radially outward and penetrates the cylindrical portion.

[0025] According to the ninth aspect of the present invention, the liquid supply section opens radially outward and penetrates the cylindrical section, so that the second reaction liquid can be supplied within a close range, for example, within 2 mm, from the inner and outer peripheries of the stirring blades where the shear force is the highest.

[0026] A tenth aspect of the present invention is a crystallization method including: a crystallization step of mixing a plurality of raw material solutions and growing particles derived from the raw materials in the plurality of raw material solutions in a crystallizer; and a circulation step of circulating a slurry containing the particles discharged from an outlet of the crystallizer to an inlet of the crystallizer by flowing the slurry through a circulation pipeline having a serpentine bend.

[0027] According to the tenth aspect of the present invention, the slurry discharged from the crystallizer flows through the circulation pipeline, so that the residence time of the slurry can be adjusted without the need for complex flow analysis. [Effects of the Invention]

[0028] According to the present invention, a crystallization system and a crystallization method can be obtained that can retain fine particles crystallized in a crystallizer without requiring a retention tank. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram of a crystallization system according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram of a crystallization system according to a second embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram of a crystallization system according to a third embodiment of the present invention. [Figure 4] FIG. 1 is a schematic diagram of a first modified example of the crystallization system of the first embodiment according to the present invention. [Figure 5] FIG. 2 is a schematic diagram of a second modified example of the crystallization system of the first embodiment according to the present invention. [Figure 6] FIG. 2 is a schematic diagram of a third modified example of the crystallization system of the first embodiment according to the present invention. [Figure 7] FIG. 1 is a schematic diagram of a fourth modified example of the crystallization system of the first embodiment according to the present invention. [Figure 8] FIG. 10 is a schematic diagram of a fifth modified example of the crystallization system of the first embodiment according to the present invention. [Figure 9] FIG. 10 is a schematic diagram of a sixth modified example of the crystallization system of the first embodiment according to the present invention. [Figure 10] FIG. 10 is a schematic diagram of a seventh modified example of the crystallization system of the first embodiment according to the present invention. [Figure 11] FIG. 10 is a schematic diagram of an eighth modified example of the crystallization system of the first embodiment according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] First Embodiment A crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallization system 10A includes a crystallizer 4 that mixes multiple raw material solutions to generate particles derived from the raw materials in these multiple raw material solutions, a circulation pipeline Po that is provided downstream of the crystallizer 4 and circulates a slurry D1 discharged from an outlet 6 of the crystallizer 4 to an inlet 5a of the crystallizer 4, and a circulation pump 30 that circulates the slurry D1 between the crystallizer 4 and the circulation pipeline Po.

[0031] The circulation pipeline Po has a bent portion Pp, which is a serpentine pipeline. The circulation pipeline Po further has a pipe 22 connecting the crystallizer 4 to the bent portion Pp, a pipe 23 connecting the circulation pump 30 to the bent portion Pp, and a pipe 24 connecting the circulation pump 30 to the crystallizer 4. The bent portion Pp is not limited to a serpentine shape and may have a spiral shape.

[0032] The circulation pump 30 is a circulation pump that has the function of circulating the slurry D1 between the crystallizer 4 and the bent portion Pp in an adjustable flow rate. However, the circulation pump 30 is not necessarily limited to a circulation pump as long as it has a similar function. For example, an impeller with a controllable rotation speed may be provided in the pipe 23 or the pipe 24.

[0033] The crystallizer 4 comprises a cylindrical reaction vessel 1 with a bottom and a vertically oriented central axis O1, and a cylindrical agitator Wc. The agitator Wc is rotatable around a hollow rotary shaft 3 extending upward along the central axis O1 from the center of the agitator Wc in a plan view. The agitator Wc is housed inside the reaction vessel 1, with the central axis O1 as the central axis. The rotary shaft 3 is rotated by torque supplied via a belt from a prime mover (not shown) installed outside the crystallizer 4. The prime mover is not particularly limited as long as it generates rotational power, such as a motor or engine. The belt that transmits the torque to the rotary shaft 3 is not particularly limited as long as it can transmit rotational force, such as a chain or gears. The bottom of the reaction vessel 1 may be flat as shown in the figure, or may be cone-shaped with a downward convexity. The top of the reaction vessel 1 is provided with an outlet 6 through which a slurry containing particles (crystals) produced in the reaction vessel 1 can be discharged to the next process. A pressure indication controller that maintains or adjusts the pressure of the slurry D1 discharged from the discharge port 6 to the pipe 22 is provided in the pipe 22.

[0034] An inlet 5a is provided at the bottom of the reaction vessel 1 to supply the first reaction liquid L1 and the slurry D1 that has flowed through the circulation pipe Po. The first reaction liquid L1 is supplied with an external auxiliary material S A and S B From the tank storing the auxiliary material S A and S B The auxiliary material S of the first reaction solution L1 is supplied and mixed. A and S BThe flow rate of the first reaction liquid L1 is maintained or adjusted by flow indication controllers FIC2 and FIC3. A desired amount of the first reaction liquid L1 is supplied to the reaction vessel 1 from the inlet 5a. The supply amount of the first reaction liquid L1 from the inlet 5a can be adjusted to a desired amount by adjusting the rotation speed of the circulation pump 30, for example. A pressure indicator PI1 is provided in the pipe 24 through which the first reaction liquid L1 flows, as needed. Further, a second reaction liquid L2 is supplied into the reaction vessel 1 from a liquid supply part 5b provided on the stirring blade Wc. M The flow rate of the second reaction liquid L2 is maintained or adjusted by a fuel indicating controller FIC1. Crystallized fine particles are produced by reaction between the first reaction liquid L1 and the second reaction liquid L2 supplied into the reaction vessel 1. The slurry D1 is a fluid containing these fine particles.

[0035] The bent portion Pp is composed of multiple straight pipe sections (Po1, Po2, Po3, Po4, Po5, Po6) with an inner diameter r2 that are spaced apart and facing approximately the same direction, multiple curved pipe sections C (C1, C2, C3, C4, C5) with an inner diameter r3 that separably or detachably connect adjacent straight pipe sections Po1, Po2, Po3, Po4, Po5, Po6, and a fixing plate 21 that fixes the multiple straight pipe sections. "Separable" means that curved pipe section C, which was provided to connect straight pipe section Po5 and straight pipe section Po6, such as curved pipe section C5 shown by a dotted line in FIG. 1, can be separated from straight pipe sections Po5 and Po6. As a method of attaching and detaching the curved pipe section C5 to the straight pipe sections Po5 and Po6, flanges (not shown) may be provided at both ends of the curved pipe section C5 and at the left ends of the straight pipe sections Po5 and Po6, and the curved pipe section C5 may be attached and detached to and from the straight pipe sections Po5 and Po6 by fastening and loosening the flanges using bolts, nuts, etc. The attachment and detachment method is not limited to this, and as long as the curved pipe section C5 is freely attachable and detachable, it may also be attached and detached by screwing both ends of the curved pipe section C5 to the left ends of the straight pipe sections Po5 and Po6, without being limited to the method using flanges. Although the fixed plate 21 is rectangular in FIG. 1, the material and shape thereof are not particularly limited as long as the multiple straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 can be held fixed to the fixed plate 21. As described above, in the case of multiple separable straight pipe sections and multiple curved pipe sections C, the inner surfaces of the straight pipe sections and curved pipe sections C can be easily cleaned by separating them, thereby improving the maintainability of the crystallization system 10A.

[0036] In the example of Figure 1, the straight pipe section is composed of six straight pipe sections: straight pipe section Po1, straight pipe section Po2, straight pipe section Po3, straight pipe section Po4, straight pipe section Po5, and straight pipe section Po6, and the curved pipe section C is composed of five curved pipe sections: curved pipe section C1, curved pipe section C2, curved pipe section C3, curved pipe section C4, and curved pipe section C5, but is not limited to this example. The straight pipe section Po may be composed of six or more straight pipe sections Po, or may be composed of six or less straight pipe sections Po. The number of curved pipe sections C increases or decreases according to the number of straight pipe sections Po. For example, in the example of FIG. 1, the second end of the curved pipe section C2, the first end of which is connected to the right end of the straight pipe section Po3, may be connected to the left end of the piping 22. In this case, the curved pipe section C2 may be provided with a bellows section that is flexible and bendable, making the curved pipe section C2 flexible.

[0037] In this way, the pipeline length of the bent section Pp, i.e., the total length of the straight pipe sections and the curved pipe sections C (the number of straight pipe sections and curved pipe sections C), can be adjusted as desired to retain the slurry D1 for the desired retention time. That is, if a longer retention time is desired, it is desirable to increase the number of straight pipe sections and curved pipe sections C to lengthen the pipeline length of the bent section Pp, and if a shorter retention time is desired, it is desirable to decrease the number of straight pipe sections and curved pipe sections C to shorten the pipeline length of the bent section Pp.

[0038] Here, the flow rate of the slurry D1 is determined by the specific gravity and diameter of the particles that make up the slurry D1. That is, the settling speed of the particles that make up the slurry D1 is determined by the specific gravity and diameter of the particles that make up the slurry D1, so the flow rate of the slurry D1 is determined so that the slurry D1 flows through the piping without settling. Therefore, the pipe length of the bent portion Pp can be calculated from the desired residence time of the slurry D1 and the flow rate of the slurry D1 that prevents the slurry D1 from settling.

[0039] The crystallizer 4 and the bent portion Pp are connected by a pipe 22 having an inner diameter r1. The bent portion Pp and the circulation pump 30 are connected by a pipe 23 having an inner diameter r4. The circulation pump 30 and the crystallizer 4 are connected by a pipe 24 having an inner diameter r5. 1, the inner diameter of the circulation pipeline Po, i.e., the inner diameter r1 of the pipe 22, the inner diameter r2 of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6, the inner diameter r3 of the curved pipe sections C1, C2, C3, C4, and C5, the inner diameter r4 of the pipe 23, and the inner diameter r5 of the pipe 24, are all the same. In this case, the cross-sectional areas of the pipe 22, the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6, the curved pipe sections C1, C2, C3, C4, and C5, the pipe 23, and the pipe 24 are constant, which makes it easier to analyze the flow of the slurry D1 flowing through the pipelines. However, without being limited to the above example, the inner diameters of the circulation pipeline Po, i.e., the inner diameter r1 of the pipe 22, the inner diameter r2 of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6, the inner diameter r3 of the curved pipe sections C1, C2, C3, C4, and C5, the inner diameter r4 of the pipe 23, and the inner diameter r5 of the pipe 24 may be different from one another. In this case, the flow analysis may be performed taking into account the different inner diameters.

[0040] The pipe 23 through which the slurry D1 discharged from the bent portion Pp flows is connected to a conduit connected to a second circulation pump 31 driven by a motor M. This conduit extracts the slurry D1 from the pipe 23 and collects it to produce a product. A flow indication controller FIC4 is provided between the motor M and the second circulation pump 31 to maintain or adjust the flow rate of the slurry D1 extracted to the outside of the crystallization system 10A. Like the circulation pump 30, the second circulation pump 31 is a slurry discharge pump that has the function of circulating the slurry at an adjustable flow rate. However, the second circulation pump 31 is not necessarily limited to a slurry discharge pump as long as it has the function of extracting the slurry D1 from the pipe 23. For example, an impeller with a controllable rotation speed may be provided in the conduit. The pressure of the slurry D1 in the pipe 23 immediately after the slurry D1 is drawn out is monitored by a pressure indicator PI2 as required.

[0041] According to the crystallization system 10A equipped with the circulation pipeline Po having such a bent portion Pp, the particle-containing slurry D1 produced in the crystallizer 4 can be easily and completely mixed uniformly by controlling the flow rate of the circulation pump 30. Furthermore, by adjusting the pipeline length of the bent portion Pp, the particle-containing slurry D1 produced in the crystallizer 4 can be retained for a desired time without requiring a retention tank. Therefore, the retention time of the slurry D1 in the bent portion Pp can be adjusted without performing the complex flow analysis of the slurry D1 that would be required if a retention tank were used. Note that a retention tank (not shown) may be added to the crystallization system 10A.

[0042] Second Embodiment Next, a crystallization system 10B according to a second embodiment will be described with reference to Fig. 2. Only differences from the first embodiment will be described below, and the same reference numerals will be used to designate the same members as those in the first embodiment, and description thereof will be omitted.

[0043] The crystallization system 10B differs from the crystallization system 10A of the first embodiment in that a second bend Ppa is provided in addition to the bend Pp (first bend).

[0044] The second bent portion Ppa has a configuration similar to that of the first bent portion Pp. A branched pipe 22a extends from the middle of the pipe 22 toward the second bent portion Ppa. The slurry D1 discharged from the second bent portion Ppa passes through a pipe 23a and merges with the pipe 23 through which the slurry D1 discharged from the first bent portion Pp flows.

[0045] 2, valves V1 and V2 are provided at the inlet of pipe 22a and the outlet of pipe 23a. By opening valves V1 and V2, slurry D1 can be made to flow through both first bent portion Pp and second bent portion Ppa. On the other hand, by closing valves V1 and V2, slurry D1 can be made to flow only through first bent portion Pp, resulting in a configuration similar to that of the crystallization system 10A of the first embodiment.

[0046] According to this crystallization system 10B, the slurry D1 can be made to flow not only through the first bent portion Pp but also through the second bent portion Ppa depending on the flow rate of the slurry D1.

[0047] Third Embodiment Next, a crystallization system 10C according to a third embodiment will be described with reference to Fig. 3. Only differences from the first embodiment will be described below, and the same reference numerals will be used to designate the same members as those in the first embodiment, and description thereof will be omitted.

[0048] The crystallization system 10C differs from the crystallization system 10A of the first embodiment in that at least a part of the bent portion Pp is provided inside the temperature adjustment tank 13.

[0049] The temperature control tank 13 is a component that maintains a unidirectional flow of a refrigerant CW, such as cold water, inside the temperature control tank 13 by a pump (not shown). If at least a portion of a bent portion Pp is provided in the temperature control tank 13, the refrigerant collides with the straight pipe portions Po1, Po2, Po3, Po4, Po5, and Po6 of the bent portion Pp. In this case, heat is exchanged between the slurry D1 flowing through the straight pipe portions Po1, Po2, Po3, Po4, Po5, and Po6 of the bent portion Pp and the refrigerant CW via the components that make up the straight pipe portions Po1, Po2, Po3, Po4, Po5, and Po6. This allows the slurry D1 to be cooled or heated. 3, the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 are arranged substantially perpendicular to the flow direction of the refrigerant CW, but they do not necessarily have to be arranged substantially perpendicular to the flow direction of the refrigerant CW, and may be arranged at an angle other than perpendicular. Also, heat exchange with the refrigerant CW may occur at the curved pipe section C of the bent section Pp, or heat exchange with the refrigerant CW may occur at both the straight pipe section and the curved pipe section C of the bent section Pp.

[0050] Here, the temperature control capability for the slurry D1 can be adjusted by adjusting the length of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 or the number of straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 in the bent section Pp. For example, if a heat quantity Q1 from the slurry D1 having a heat quantity Q flowing through the straight pipe section Po1 is transferred to the refrigerant CW by heat exchange, a heat quantity Q2 from the slurry D1 having a heat quantity (Q-Q1) flowing through the straight pipe section Po2 is transferred to the refrigerant CW by heat exchange. Furthermore, if a heat quantity Q3 from the slurry D1 having a heat quantity (Q-(Q1+Q2)) flowing through the straight pipe section Po3 is transferred to the refrigerant CW by heat exchange, the heat quantity of the slurry D1 flowing through the straight pipe section Po4 becomes (Q-(Q1+Q2+Q3)). By repeating this process a desired number of times, the heat quantity of the slurry D1 can be reduced, thereby cooling the slurry D1 by a desired amount. The same applies to the case where the slurry D1 is heated.

[0051] According to such a crystallization system 10C, the slurry D1 can be cooled or heated by the desired amount by adjusting the pipe length of the bent section Pp where heat exchange with the refrigerant CW takes place, i.e., the pipe length or number of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6.

[0052] <First Modification of First Embodiment> A crystallization system 10A1 according to a first modified example of the crystallization system 10A according to the first embodiment will be described below with reference to Fig. 4. In the following description, only the differences from the crystallization system 10A according to the first embodiment will be described, and the same components will be given the same reference numerals and their description will be omitted.

[0053] The crystallization system 10A1 according to the first modification is different from the crystallizer 4 in that the crystallizer 4a is provided with an agitator blade W.

[0054] The agitator W comprises a cylindrical portion 2 and a disk-shaped disk portion 8 whose outer periphery is fixed to the inner circumferential surface 2i of the cylindrical portion 2. The disk portion 8 is provided at a position that is approximately half the height of the cylindrical portion 2, but is not limited to this example and may be provided below or above approximately half the height of the cylindrical portion 2. A rotating shaft 3 is fixed to the center of the disk portion 8 in a plan view. The hollow interior of the rotating shaft 3 is a conduit P1. Within the disk portion 8, a plurality of conduits P2 extend radially from the center toward the outer periphery. The conduits P1 of the rotating shaft 3 and the conduits P2 of the disk portion 8 are connected to each other. The rotating shaft 3 of the agitator W is connected to a main raw material S provided outside the crystallizer 4. M The second reaction liquid L2 is supplied from a tank storing the second reaction liquid L2. The second reaction liquid L2 is supplied to a hollow pipe P1 in the rotating shaft 3 via a rotary joint R, and then supplied to a pipe P2 in the disk unit 8. The tip of the pipe P2 on the outer side in the radial direction of the reaction tank 1 opens downward and serves as a liquid supply unit 5b from which the second reaction liquid L2 is discharged. Therefore, the disk unit 8 is provided with a plurality of liquid supply units 5b spaced apart in the circumferential direction of the disk unit. The number of liquid supply units 5b provided is, for example, eight. The number of liquid supply units 5b is not limited, but it is desirable to provide them symmetrically with respect to the central axis O1.

[0055] In this modified example, the distance between the inner peripheral surface 2i of the cylindrical portion 2 of the impeller W and the center of the liquid supply portion 5b is 2 mm or less. Furthermore, if the distance (clearance) between the outer peripheral surface 2o of the cylindrical portion 2 of the impeller W and the inner peripheral surface 1i of the reaction vessel 1 is L3, and the height along the central axis O1 of the impeller W (cylindrical portion 2) is H, the ratio of H to L3, H / L3, is preferably 10 or greater. Furthermore, it is more preferable that H / L3 is 25 or greater. Therefore, even if a device of a different size is used, a similar device can be manufactured based on this ratio. The impeller W rotates at a peripheral speed of 5 m / s or greater and 50 m / s or less. The ratio of H / L3 may be different from the above-mentioned ratio depending on the purpose. For example, if it is desired to suppress crystal fracture, the ratio may be lowered from the above-mentioned value.

[0056] The cylindrical portion 2 of the impeller W is provided with a plurality of holes h that penetrate the cylindrical portion 2 in the radial direction. These holes h allow the first reaction liquid L1, the second reaction liquid L2, or a mixture thereof to flow through. Therefore, the first reaction liquid L1, the second reaction liquid L2, or a mixture thereof can move from the inside to the outside of the impeller W or from the outside to the inside of the impeller W through the plurality of holes h. In addition to the holes h, the disk portion 8 may be provided with a plurality of holes 9 that penetrate in the direction of the central axis O1. In this case, the first reaction liquid L1, the second reaction liquid L2, or a mixture thereof can move from the inside to the outside of the impeller W or from the outside to the inside of the impeller W through the holes 9 in addition to the plurality of holes h.

[0057] In this crystallizer 4a, a desired amount of the first reaction liquid L1 is supplied to the reaction vessel 1 through the inlet 5a. The amount of the first reaction liquid L1 supplied may be sufficient to fill the reaction vessel 1 (to a liquid-filled state), or may be sufficient to press the first reaction liquid L1 against the inner circumferential surface 1i of the reaction vessel 1 due to centrifugal force generated by the first reaction liquid L1 as the stirring impeller W rotates and the first reaction liquid L1 undergoes circular motion about the central axis O1 of the reaction vessel 1, thereby forming a liquid film of the first reaction liquid L1 on the inner circumferential surface 1i of the reaction vessel 1. The following description will be given assuming that the first reaction liquid L1 is supplied to a liquid-filled state. Alternatively, the first reaction liquid L1 may be supplied to a liquid-filled state or a liquid film-forming state, and then the supply of the first reaction liquid L1 may be stopped before the reaction in the reaction vessel 1 is started. Alternatively, the reaction in the reaction vessel 1 may be continued while maintaining the first reaction liquid L1 at a flow rate sufficient to fill the reaction vessel 1 or a liquid film-forming state. For example, by providing an opening adjustment valve (not shown) at the outlet 6 and adjusting the opening of this opening adjustment valve, the reaction tank 1 can be selected to be in either a liquid-filled state or a liquid film state in which a liquid film is formed.

[0058] With the reaction vessel 1 filled with the first reaction liquid L1, the agitator W is rotated and the second reaction liquid L2 is discharged from the liquid supply section 5b along the inner circumferential surface 2i of the cylindrical portion 2 of the agitator W, thereby supplying the second reaction liquid L2 into the reaction vessel 1. In this manner, the second reaction liquid L2 discharged from the liquid supply section 5b along the inner circumferential surface 2i of the cylindrical portion 2 of the agitator W comes into contact with the first reaction liquid L1 that is rotating in association with the rotation of the agitator W near the inner circumferential surface 2i of the cylindrical portion 2 of the agitator W in the reaction vessel 1 filled with the first reaction liquid L1. This contact between the first reaction liquid L1 and the second reaction liquid L2 causes a reaction to occur, producing particles.

[0059] In this case, the second reaction liquid L2 is supplied to the first reaction liquid L1 from the liquid supply section 5b of the stirring blade W, which is rotating at a peripheral speed of 5 m / s or more and 50 m / s or less, so that the second reaction liquid L2 can be uniformly mixed with the first reaction liquid L1.

[0060] Here, due to the centrifugal force generated in the mixture of the first reaction liquid L1 rotating with the rotation of the impeller W and the second reaction liquid L2 discharged from the liquid supply portion 5b of the impeller W rotating at a peripheral speed of 5 m / s to 50 m / s, the first reaction liquid L1, the second reaction liquid L2, and the mixture (hereinafter sometimes collectively referred to as the mixture) move radially outward from the cylindrical portion 2 of the impeller W, pass through multiple holes h provided in the cylindrical portion 2 of the impeller W, collide with the inner circumferential surface 1i of the reaction vessel 1, and then move vertically along the inner circumferential surface 1i of the reaction vessel 1. The mixture that moves mainly downward is attracted by the radially outward flow caused by the centrifugal force generated by the rotation of the impeller W, passes through multiple holes h provided in the cylindrical portion 2 of the impeller W, collide with the inner circumferential surface 1i of the reaction vessel 1, and then moves vertically along the inner circumferential surface 1i of the reaction vessel 1, thereby generating convection. Here, when the mixed liquid passes through the multiple holes h, the effect of the throttle flow path causes the mixed liquid to accelerate radially outward, so the radially outward flow velocity of the mixed liquid is highest near the multiple holes h. Furthermore, a circumferential shear force is applied to the mixed liquid present between the outer peripheral surface 2o and inner peripheral surface 2i of the cylindrical portion 2 of the agitator W, which rotates at a peripheral speed of 5 m / s to 50 m / s, and the inner peripheral surface 1i of the fixed reaction vessel 1. The shear force applied to the mixed liquid is greater the closer it is to the inner peripheral surface 2i and outer peripheral surface 2o of the cylindrical portion 2 of the agitator W. The shear force applied to the mixed liquid is a major factor in determining the particle size and uniformity of the resulting particles. In particular, the greater the applied shear force, the finer the particles obtained.

[0061] In this modified crystallizer 4a, the liquid supply unit 5b is located on the outer edge of the disk unit 8. Specifically, as described above, the distance between the inner circumferential surface 2i of the cylindrical portion 2 of the impeller W and the center of the liquid supply unit 5b is 2 mm or less. Therefore, at the reaction initiation point where the second reaction liquid L2 discharged from the liquid supply unit 5b along the inner circumferential surface 2i of the cylindrical portion 2 of the impeller W first comes into contact with the first reaction liquid L1 rotating with the rotation of the impeller W near the inner circumferential surface 2i of the cylindrical portion 2 of the impeller W, maximum shear force is applied in addition to the radially outward flow due to centrifugal force and the effect of the throttle flow channel. Therefore, the region with the greatest applied shear force can be defined as the reaction initiation point. Specifically, the reaction initiation point can be formed in a region close to the inner circumferential surface 2i and outer circumferential surface 2o of the cylindrical portion 2 of the impeller W, for example, within 2 mm. Here, the mixed liquid can move from the inner circumferential side to the outer circumferential side of the cylindrical portion 2 through the multiple holes h. Therefore, the shear force promotes mixing of the first reaction liquid L1 and the second reaction liquid L2 at the reaction initiation point. Therefore, more uniform mixing of the first reaction liquid L1 and the second reaction liquid L2 is initiated from the reaction initiation point, and mixing and reaction occur in the reaction field, where the reaction occurs along the flow of the mixed liquid, thereby producing fine particles with uniform diameters. Here, the reaction initiation point refers to the area where the reaction begins, and the reaction field refers to the entire field where the reaction occurs. Therefore, the reaction initiation point is included in the reaction field. A baffle (baffle plate) (not shown) may be provided on the inner circumferential surface of the reaction vessel 1 corresponding to the upper part of the stirring blade W. When the reaction vessel 1 is filled with liquid, the baffle has the effect of suppressing the generation of vortices and promoting the stirring of the mixed liquid. On the other hand, when the reaction vessel 1 is not filled with liquid and a liquid film of the mixed liquid is formed, it is not necessary to provide a baffle. Note that the baffle is not an essential component and need not be provided. For example, if a mechanical seal (not shown) is provided at the location in the reaction vessel 1 where the rotating shaft 3 is inserted, and a completely liquid-filled state with no gas phase is achieved, the generation of vortices is suppressed, and therefore a baffle need not be provided. If a baffle is not provided, flow path resistance is reduced, and the power of the prime mover M can be reduced.

[0062] It should be noted that the same effect as in the case of the liquid-filled state can be obtained even in a state where a liquid film is formed, rather than in a liquid-filled state.

[0063] According to the crystallization system 10A1 of the first modified example including such a crystallizer 4a, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4a, and thus further improve the controllability of particle quality.

[0064] <Second Modification of First Embodiment> A crystallization system 10A2 according to a second modification of the crystallization system 10A according to the first embodiment will be described below with reference to Fig. 5. The crystallization apparatus 4b according to the second modification differs from the crystallization apparatus 4a according to the first modification in that the agitator W is replaced with an agitator Wa. In the following description, only the differences from the agitator W will be described, and overlapping descriptions will be omitted. The agitator Wa differs from the agitator W in that the liquid supply portion 5b provided on the outer edge of the disk portion 8 penetrates the cylindrical portion 2 and opens radially outward. In this agitator Wa, the second reaction liquid L2 is discharged from the liquid supply portion 5b that opens radially outward, thereby improving the radial (horizontal) dispersibility of the second reaction liquid L2 and the mixture of the first reaction liquid L1 and the second reaction liquid L2. The use of a crystallizer 4b equipped with this agitator Wa can also achieve the same effects as the crystallizer 4a equipped with the agitator W. The disk portion 8 may be provided with a plurality of holes 9 (not shown) that penetrate in the direction of the central axis O1. Such multiple holes 9 allow a portion of the mixed liquid to flow between the upper and lower sides of the agitator W via the multiple holes 9, thereby reducing the dynamic load on the agitator W. However, since the mixed liquid that passes through the multiple holes 9 does not pass through the reaction field around the agitator W but instead short-passes the reaction field, the effect of producing uniform, fine particles is reduced compared to when multiple holes 9 are not provided. Therefore, the application of holes 9 can be selected taking into account the desired particle quality and required power.

[0065] According to the crystallization system 10A2 of the second modified example including such a crystallizer 4b, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4b, and thus further improve the controllability of particle quality.

[0066] <Third Modification of First Embodiment> A crystallization system 10A3 according to a third modification of the crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallizer 4c of the third modified example differs from the second modified example in that the stirring blade Wa is replaced with a stirring blade Wb. In the following explanation, only the differences from the stirring blade Wa will be explained, and explanation of overlapping points will be omitted. In the agitating impeller Wb, the cylindrical portion 2 above the disk portion 8 of the agitating impeller Wa has a plurality of holes h penetrating in the radial direction that are blocked, and a second disk portion 15 is provided at the upper end of the cylindrical portion 2, with its outer periphery fixed to the inner circumferential surface 2i of the cylindrical portion 8. The second disk portion 15 is a disk-shaped member and has a hole at its center in a plan view through which the rotating shaft 3 passes. Except for the hole through which the rotating shaft 3 passes, there are no other holes penetrating the second disk portion 15 in the direction of the central axis O1. Therefore, the first reaction liquid L1, the second reaction liquid L2, and their mixture do not enter the inside of the second disk portion 15. In such an agitating impeller Wb, the cylindrical portion 2 above the disk portion 8 is not provided with a plurality of holes h that penetrate radially, and a second disk portion 15, the outer periphery of which is fixed to the inner circumferential surface 2i of the cylindrical portion 8, is provided at the upper end of the cylindrical portion 2. Therefore, the resistance force of the agitating impeller Wb when the agitating impeller Wb rotates is reduced, and the agitating impeller Wb can be operated with less power than the agitating impeller Wa.

[0067] According to the crystallization system 10A3 of the third modified example including such a crystallizer 4c, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4c, and thus further improve the controllability of particle quality.

[0068] <Supplementary explanation of the first embodiment> Now, returning to Figs. 1 to 3, the stirring blades Wc of the first to third embodiments will be described in detail. The crystallizer 4 in the first embodiment differs from the crystallizer 4a of the first modified example shown in Fig. 4 in that the stirring blade W is replaced with the stirring blade Wc. In the following explanation, only the differences from the stirring blade W will be explained, and explanation of overlapping points will be omitted. As shown in FIG. 1, the stirring impeller Wc has a cylindrical portion 2 above the disk portion 8 of the stirring impeller W, in which multiple holes h penetrating in the radial direction are blocked, and a second disk portion 15 is provided at the upper end of the cylindrical portion 2, with its outer periphery fixed to the inner circumferential surface 2i of the cylindrical portion 8. The second disk portion 15 is a disk-shaped member and has a hole at its center in a plan view through which the rotating shaft 3 passes. Except for the hole through which the rotating shaft 3 passes, there are no other holes penetrating the second disk portion 15 in the direction of the central axis O1. Therefore, the first reaction liquid L1, the second reaction liquid L2, and their mixture cannot enter the inside of the second disk portion 15. In this type of agitator Wc, the cylindrical portion 2 above the disk portion 8 does not have a plurality of holes h that penetrate radially, and the second disk portion 15, whose outer periphery is fixed to the inner circumferential surface 2i of the cylindrical portion 8, is provided at the upper end of the cylindrical portion 2, so that the resistance force of the agitator Wc when the agitator Wc rotates is reduced. Therefore, the agitator Wc can be operated with less power than the agitator W.

[0069] According to the crystallization system 10A of the first embodiment including such a crystallizer 4, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect particle quality such as particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4, and thus further improve the controllability of particle quality.

[0070] <Fourth Modification of the First Embodiment> A crystallization system 10A4 according to a fourth modification of the crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallizer 4d of the fourth modified example differs from the crystallizer 4a of the first modified example in that the stirring blade W is replaced with a stirring blade Wd. In the following explanation, only the differences from the stirring blade W will be explained, and explanation of overlapping points will be omitted. As shown in FIG. 7, the agitator Wd differs from the agitator W in that the disk portion 8 is provided at the upper end of the cylindrical portion 2. Furthermore, the height of the cylindrical portion 2 is approximately half that of the cylindrical portion 2 of the agitator W. Using a crystallizer 4d equipped with such an agitator Wd can achieve the same effects as the crystallizer 4 equipped with the agitator W. Furthermore, because the cylindrical portion 2 is not provided above the disk portion 8, the agitator Wd can be made lighter than the agitator W. Furthermore, because the agitator Wd can have a simple structure, it can be operated with less power than the agitator W, which is expected to reduce the energy consumption of the crystallizer 4 and simplify the manufacture of the agitator Wd. Furthermore, because the height of the cylindrical portion 2 is kept short, the crystallizer 4d can be made more compact. The disk portion 8 may be provided with multiple holes 9 (not shown) penetrating in the direction of the central axis O1. In this case, the same effects as when the disk portion 8 of the agitator Wa is provided with multiple holes 9 penetrating in the direction of the central axis O1 can be expected.

[0071] According to the crystallization system 10A4 of the fourth modified example including such a crystallizer 4d, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4d, and thus further improve the controllability of particle quality.

[0072] <Fifth Modification of the First Embodiment> A crystallization system 10A5 according to a fifth modification of the crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallizer 4e of the fifth modified example differs from the crystallizer 4a of the first modified example in that the stirring blade W is replaced with the stirring blade We. In the following explanation, we will mainly focus on the differences from the stirring blade W, and will omit explanations of overlapping points. As shown in FIG. 8, the stirring impeller We includes a cylindrical columnar portion 20, a disk base 18 concentrically disposed at the upper end of the columnar portion 20, a rotating shaft 3 extending upward along the central axis O1 from the center of the disk base 18 in a plan view, and a cylindrical perforated plate 18P concentrically disposed radially outward of the columnar portion 20. The perforated plate 18P has a plurality of holes 18h penetrating the perforated plate 18P in the radial direction, allowing the first reaction liquid L1, the second reaction liquid L2, and their mixture to flow through the holes 18h. The perforated plate 18P extends downward from the outer edge of the disk base 18. The second reaction liquid can flow through conduits P1, P2, and P3 provided within the rotating shaft 3, the disk base 18, and the columnar portion 20, respectively. The pipes P1, P2, and P3 are all connected to each other. Pipe P2 extends radially outward from the lower end of pipe P1, centered on the central axis O1. Pipe P3 extends downward from the radially outer end of pipe P2 along the central axis O1. Pipes P2 and P3 are formed inside the cylindrical portion 20. A plurality of liquid supply portions 50b are provided at intervals in the vertical direction on the outer peripheral surface 20o of the cylindrical portion 20. When the mixing impeller We rotates, the rotating shaft 3, the disk base 18, the cylindrical portion 20, and the perforated plate 18P rotate together. In such an agitator impeller We, the second reaction liquid L2 is supplied into the reaction vessel 1 from a plurality of liquid supply portions 50b provided at intervals in the vertical direction on the outer peripheral surface 20o of the cylindrical portion 20, and flows through the plurality of holes 18h in the porous plate 18P while mixing and reacting with the first reaction liquid L1 in the reaction vessel 1. Therefore, the first reaction liquid L1 and the second reaction liquid L2 can be mixed more uniformly. The mixed liquid that passes through the multiple holes 18h in the perforated plate 18P collides with the inner periphery 1i of the reaction vessel 1 and then moves up and down along the inner periphery 1i of the reaction vessel 1. The mixed liquid that moves downward is attracted by the radially outward flow caused by the centrifugal force generated by the rotation of the agitating impeller We, and again passes through the multiple holes 18h in the perforated plate 18P of the agitating impeller We, where it collides with the inner periphery 1i of the reaction vessel 1 and then moves up and down along the inner periphery 1i of the reaction vessel 1, thereby creating a convection current. Here, as the mixed liquid passes through the multiple holes 18h, the mixed liquid is accelerated radially outward due to the effect of the throttle flow path, and therefore the radially outward flow velocity of the mixed liquid is highest near the multiple holes 18h. Furthermore, a circumferential shear force is applied to the mixed liquid present between the outer surface 20o of the cylindrical portion 20 of the impeller We, which rotates at a peripheral speed of 5 m / s to 50 m / s, and the inner and outer surfaces of the perforated plate 18P, and the inner surface 1i of the reaction vessel 1 to which it is fixed. The shear force applied to the mixed liquid is greater the closer it is to the outer surface 2o of the cylindrical portion 20 of the impeller We and the inner and outer surfaces of the perforated plate 18P. The shear force applied to the mixed liquid is a major factor in determining the particle size and uniformity of the resulting particles. In particular, the greater the applied shear force, the finer the particles obtained. When using the impeller We, the shear force can be applied to more locations than when using the impeller W, resulting in the production of uniform, fine particles. The second reaction liquid L2 supplied from the liquid supply section 50b can be supplied within a range of close proximity, for example, within 2 mm, from the inner and outer peripheries of the stirring impeller We where the shear force is the highest, i.e., the outer periphery 20o of the cylindrical section 20 and the inner and outer periphery of the porous plate 18P. In the example of Figure 8, four liquid supply sections 50b are provided in the vertical direction of the cylindrical section 20, but the number of liquid supply sections 50b is not limited to the example of Figure 8 and may be increased or decreased depending on the size of the reaction tank 1.

[0073] According to the crystallization system 10A5 of the fifth modified example including such a crystallizer 4e, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4e, and thus further improve the controllability of particle quality.

[0074] <Sixth Modification of the First Embodiment> A crystallization system 10A6 according to a sixth modification of the crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallizer 4f of the sixth modified example differs from the crystallizer 4a of the first modified example in that the stirring blade W is replaced with a stirring blade Wf. In the following explanation, only the differences from the stirring blade W will be mainly explained, and explanation of overlapping points will be omitted. As shown in FIG. 9, the stirring impeller Wf includes a cylindrical columnar portion 20, a rotating shaft 3 extending upward along the central axis O1 from the center of the columnar portion 20 in a plan view, and a cylindrical perforated plate 18P disposed concentrically with the columnar portion 20 on the radially outer side of the columnar portion 20. The perforated plate 18P has a plurality of holes 18h penetrating the perforated plate 18P in the radial direction, allowing the first reaction liquid L1, the second reaction liquid L2, and their mixture to flow through the holes 18h. The perforated plate 18P is fixed to a connecting rod 11 extending radially outward from the outer peripheral surface 2o of the columnar portion 20. The second reaction liquid can flow through conduits P1, P2, and P3 provided inside the rotating shaft 3 and the columnar portion 20, respectively. The conduits P1, P2, and P3 are all connected to each other. Pipe P2 extends radially outward from the lower end of pipe P1 around the central axis O1. Pipe P3 extends downward from the radially outer end of pipe P2 along the central axis O1. Pipes P2 and P3 are formed inside the cylindrical portion 20. Multiple liquid supply portions 50b are provided at intervals in the vertical direction on the outer peripheral surface 20o of the cylindrical portion 20. When the mixing impeller Wf rotates, the rotating shaft 3, the cylindrical portion 20, the connecting rod 11, and the porous plate 18P rotate integrally. Multiple connecting rods 11 are provided at equal intervals in the circumferential direction of the cylindrical portion 20. It is preferable to provide two or more connecting rods 11. The connecting rod 11 is provided at a position approximately halfway up the height of the cylindrical portion 20, but this is not limited to this example and may be provided above or below approximately halfway up the height of the cylindrical portion 20. In such an agitator Wf, the second reaction liquid L2 is supplied into the reaction tank 1 from a plurality of liquid supply portions 50b provided at intervals in the vertical direction on the outer circumferential surface 20o of the cylindrical portion 20, and flows through the plurality of holes 18h of the porous plate 18P while mixing and reacting with the first reaction liquid L1 in the reaction tank 1. Therefore, the first reaction liquid L1 and the second reaction liquid L2 can be mixed more uniformly. The mixed liquid that passes through the multiple holes 18h in the perforated plate 18P collides with the inner periphery 1i of the reaction vessel 1 and then moves vertically along the inner periphery 1i of the reaction vessel 1. The mixed liquid that moves vertically is attracted by a radially outward flow caused by centrifugal force generated by the rotation of the agitator Wf, and again passes through the multiple holes 18h in the perforated plate 18P of the agitator Wf, where it collides with the inner periphery 1i of the reaction vessel 1 and then moves vertically along the inner periphery 1i of the reaction vessel 1, thereby creating convection. Here, as the mixed liquid passes through the multiple holes 18h, the mixed liquid is accelerated radially outward due to the effect of the throttle flow path, and the radially outward flow velocity of the mixed liquid is highest near the multiple holes 18h. Furthermore, a circumferential shear force is applied to the mixed liquid present between the outer surface 20o of the cylindrical portion 20 of the impeller Wf, which rotates at a peripheral speed of 5 m / s to 50 m / s, and the inner and outer surfaces of the perforated plate 18P, and the inner surface 1i of the reaction vessel 1 to which it is fixed. The shear force applied to the mixed liquid is greater the closer it is to the outer surface 2o of the cylindrical portion 20 of the impeller Wf and the inner and outer surfaces of the perforated plate 18P. The shear force applied to the mixed liquid is a major factor in determining the particle size and uniformity of the resulting particles. In particular, the greater the applied shear force, the finer the particles obtained. When using the impeller Wf, the shear force can be applied to more locations, allowing for the production of uniform, fine particles. The second reaction liquid L2 supplied from the liquid supply section 50b can be supplied within a range of close proximity, for example, within 2 mm, from the inner and outer peripheries of the stirring blade Wf ​​where the shear force is the highest, i.e., the outer periphery 20o of the cylindrical section 20 and the inner and outer periphery of the porous plate 18P. In the example of Figure 9, four liquid supply sections 50b are provided in the vertical direction of the cylindrical section 20, but the number of liquid supply sections 50b is not limited to the example of Figure 10 and may be increased or decreased depending on the size of the reaction tank 1.

[0075] According to the crystallization system 10A6 of the sixth modified example including such a crystallizer 4f, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4f, thereby further improving the controllability of particle quality.

[0076] <Seventh Modification of the First Embodiment> A crystallization system 10A7 according to a seventh modification of the crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallizer 4g of the seventh modified example differs from the crystallizer 4e of the fifth modified example in that the stirring blade We is replaced with a stirring blade Wg. In the following explanation, only the differences from the stirring blade We will be explained, and overlapping explanations will be omitted. As shown in Fig. 10, the mixing impeller Wg has a wider gap between the outer peripheral surface 20o of the cylindrical portion 2 and the inner peripheral surface of the porous plate 18P than the mixing impeller We of the fifth modified example. In addition, an extension pipe 12 is provided that extends further radially outward from the liquid supply portion 50b that opens radially outward in the mixing impeller We, and the tip of the extension pipe 12 serves as the liquid supply portion 50b. This type of impeller Wg allows for a wider gap between the outer peripheral surface 20o of the cylindrical portion 20 and the inner peripheral surface of the perforated plate 18P, facilitating the flow of the first reaction liquid L1, the second reaction liquid L2, and their mixture between the cylindrical portion 20 and the perforated plate 18P. This facilitates the circulation of the reaction liquid, enabling the production of uniform, fine particles. Furthermore, the second reaction liquid L2 supplied from the liquid supply unit 50b can be supplied to the inner and outer peripheries of the impeller Wg, where the shearing force is highest, within a close range, for example, within 2 mm, of the inner and outer peripheral surfaces of the perforated plate 18P.

[0077] According to the crystallization system 10A7 of the seventh modified example including such a crystallizer 4g, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4g, thereby further improving the controllability of particle quality.

[0078] <Eighth Modification of First Embodiment> A crystallization system 10A8 according to an eighth modification of the crystallization system 10A according to the first embodiment will be described below with reference to FIG. The crystallizer 4h of the eighth modified example differs from the crystallizer 4f of the sixth modified example in that the stirring blade Wf ​​is replaced with the stirring blade Wh. In the following explanation, only the differences from the stirring blade Wf ​​will be explained, and explanation of overlapping points will be omitted. As shown in Fig. 11, the mixing impeller Wh has a wider gap between the outer peripheral surface 20o of the cylindrical portion 20 and the porous plate 18P than the mixing impeller Wf of the eighth modification. Also, the mixing impeller Wf has an extension pipe 12 extending further radially outward from the liquid supply portion 50b that opens radially outward, and the tip of the extension pipe 12 serves as the liquid supply portion 50b. With this type of impeller Wh, the gap between the outer peripheral surface 20o of the cylindrical portion 20 and the inner peripheral surface of the perforated plate 18P can be increased, making it easier for the first reaction liquid L1, the second reaction liquid L2, and their mixture to flow between the cylindrical portion 20 and the perforated plate 18P. This promotes circulation of the reaction liquid, allowing for the production of uniform, fine particles. Furthermore, the second reaction liquid L2 supplied from the liquid supply section 50b can be supplied within close proximity, for example, within 2 mm, of the inner and outer peripheries of the impeller Wg, where shearing force is highest, i.e., the inner and outer peripheries of the perforated plate 18P.

[0079] According to the crystallization system 10A8 of the eighth modified example including such a crystallizer 4h, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4h, thereby further improving the controllability of particle quality.

[0080] Among the above-mentioned modified examples, the impeller Wc of the crystallizer 4 according to the first embodiment, the impeller W of the crystallizer 4a according to the first modified example, and the impeller Wd of the crystallizer 4d according to the fourth modified example, in which the liquid supply section 5b opens downward, can mix the first reaction liquid L1 and the second reaction liquid L2 more uniformly.

[0081] <Crystallization method> It should be noted that the production of particles by using the crystallization system described in the above embodiment and modifications can be considered as a crystallization method.

[0082] For example, the crystallization system 10A of the first embodiment can be considered to be a crystallization method including a crystallization step of mixing a plurality of raw material solutions and growing particles derived from the raw materials in the plurality of raw material solutions in a crystallizer 4, and a circulation step of circulating a particle-containing slurry D1 discharged from an outlet 6 of the crystallizer 4 to an inlet 5a of the crystallizer 4 by flowing the slurry D1 through a circulation pipe Po having a serpentine bend Pp. Such a crystallization method can achieve the same effects as those of the crystallizer system 10A of the first embodiment.

[0083] Furthermore, the crystallization system 10A of the first embodiment can be regarded as a crystallization method in which the inner diameter of the circulation pipeline Po is constant in the crystallization system 10A. According to such a crystallization method, the same effects as those of the crystallization system 10A of the first embodiment can be obtained.

[0084] Furthermore, the crystallization system 10B of the second embodiment can be regarded as a crystallization method in which a plurality of bent portions Pp are provided in the crystallization system 10A. According to such a crystallization method, the same effects as those of the crystallization system 10B of the second embodiment can be obtained.

[0085] Furthermore, the crystallization system 10C of the third embodiment can be regarded as a crystallization method in which at least a part of the bent portion Pp in the crystallization system 10A is provided inside the temperature control tank. According to such a crystallization method, the same effects as those of the crystallization system 10C of the third embodiment can be obtained.

[0086] Furthermore, the crystallization system 10A of the first embodiment can be regarded as a crystallization method in which the bending section Pp is composed of a plurality of separable straight pipe sections and a plurality of curved pipe sections C. According to such a crystallization method, the same effects as those of the crystallization system 10A of the first embodiment can be obtained.

[0087] Furthermore, a crystallization system 10A1 according to a first modification of the crystallization system 10A of the first embodiment includes a crystallizer 4a, a stirring blade W having a plurality of radially penetrating holes h and rotating about a central axis O1, a bottomed cylindrical reaction vessel 1 concentrically housing the stirring blade W, an inlet 5a for supplying a first reaction liquid L1 to the reaction vessel 1, and a liquid supply unit 5b provided on the stirring blade W and capable of supplying a second reaction liquid L2. This crystallization method can be considered to include a first liquid supply step for supplying the first reaction liquid L1 to the reaction vessel 1 from the inlet 5a and a second liquid supply step for supplying the second reaction liquid L2 from the liquid supply unit to the reaction vessel 1. This crystallization method can achieve the same effects as the crystallization system 10A1 according to the first modification of the crystallization system 10A of the first embodiment.

[0088] Furthermore, the crystallization system 10A1 according to a first modification of the crystallization system 10A of the first embodiment is the crystallization system 10A1, in which the stirring impeller W further comprises a cylindrical portion 2, a disk-shaped portion 8 whose outer periphery is fixed to the inner circumferential surface of the cylindrical portion 2, and a rotating shaft 3 extending upward from the center of the disk portion 8 in a plan view along the central axis O1, and the second reaction liquid L2 can flow through the interior of the disk portion 8 and the rotating shaft O1, and the second reaction liquid L2 is supplied downward from the outer periphery of the disk portion 8 in the second liquid supply step. This crystallization method can be considered to have the same effects as the crystallization system 10A1 according to the first modification of the crystallization system 10A of the first embodiment.

[0089] Furthermore, the crystallization system 10A2 according to a second modification of the crystallization system 10A of the first embodiment is the same as the crystallization system 10A1 according to the first modification of the crystallization system 10A of the first embodiment, except that the stirring impeller W further comprises a cylindrical portion 2, a disk-shaped portion 8 whose outer periphery is fixed to the inner circumferential surface 2i of the cylindrical portion 2, and a rotation axis O1 extending upward along the central axis from the center of the disk portion 8 in a plan view, and the second reaction liquid L2 can flow through the interior of the disk portion 8 and the rotation axis O1, and in the second liquid supply step, the second reaction liquid L2 is supplied radially outward from the outer periphery of the disk portion 8 through the cylindrical portion 2. This crystallization method can achieve the same effects as the crystallization system 10A2 according to the second modification of the crystallization system 10A of the first embodiment.

[0090] Furthermore, the crystallization system 10A of the first embodiment and the crystallization system 10A3 of the third modified example of the crystallization system 10A of the first embodiment can be considered to be a crystallization method in which, in the agitator W of the crystallization system 10A1 of the first modified example of the crystallization system 10A of the first embodiment and the agitator Wa of the crystallization system 10A2 of the second modified example of the crystallization system 10A of the first embodiment, a plurality of radially penetrating holes h are blocked in the cylindrical portion 2 above the disk portion 8, and a disk-shaped second disk portion 15, the outer periphery of which is fixed to the inner circumferential surface of the cylindrical portion 2, is provided at the upper end of the cylindrical portion 2. According to such a crystallization method, the same effects as those of the crystallization system 10A of the first embodiment and the crystallization system 10A3 of the third modified example of the crystallization system 10A of the first embodiment can be obtained.

[0091] Furthermore, the crystallization system 10A4 according to the fourth modification of the crystallization system 10A of the first embodiment can be regarded as a crystallization method in which the disk portion 8 is provided at the upper end of the agitator W in the crystallization system 10A1 according to the first modification of the crystallization system 10A of the first embodiment. This crystallization method can achieve the same effects as the crystallization system 10A4 according to the fourth modification of the crystallization system 10A of the first embodiment.

[0092] Furthermore, a crystallization system 10A5 according to a fifth modification of the crystallization system 10A of the first embodiment is a crystallization system 10A1 according to the first modification of the crystallization system 10A of the first embodiment, wherein the stirring blade W comprises a cylindrical columnar portion 20, a disk base portion 18 provided concentrically with the columnar portion at the upper end of the columnar portion 20, a rotating shaft 3 extending upward along the central axis O1 from the center of the disk base 18 in a plan view, and a cylindrical portion 20 provided radially outward from the columnar portion 20. and a cylindrical perforated plate 18P disposed concentrically with the rotation axis O1, the perforated plate 18P extending downward from the outer edge of the disk base 18, allowing a second reaction liquid L2 to flow through the interior of the rotation axis O1, the disk base 18, and the cylindrical portion 20, and in the second liquid supply step, the second reaction liquid L2 is supplied radially outward from a plurality of liquid supply portions 50b disposed at intervals in the vertical direction on the outer peripheral surface 20o of the cylindrical portion 20. Such a crystallization method can achieve the same effects as the crystallization system 10A4 according to the fifth modified example of the crystallization system 10A of the first embodiment.

[0093] Furthermore, a crystallization system 10A6 according to a sixth modified example of the crystallization system 10A of the first embodiment is the same as the crystallization system 10A1 according to the first modified example of the crystallization system 10A of the first embodiment, except that the stirring impeller W includes a cylindrical columnar portion 20, a rotating shaft 3 extending upward along the central axis O1 from the center of the columnar portion 20 in a plan view, and a cylindrical perforated plate 18P provided concentrically with the columnar portion 20 on the radially outer side of the columnar portion 20, and the perforated plate 18P is fixed to a connecting rod 11 extending radially outward from the outer peripheral surface 20o of the columnar portion 20, allowing the second reaction liquid L2 to flow between the rotating shaft O1 and the columnar portion 20, and the second liquid supply step can be regarded as a crystallization method in which the second reaction liquid L2 is supplied radially outward from a plurality of liquid supply portions 50b provided at intervals in the vertical direction on the outer peripheral surface 20o of the columnar portion 20. According to this crystallization method, it is possible to obtain the same effects as those of the crystallization system 10A6 according to the sixth modified example of the crystallization system 10A of the first embodiment.

[0094] Furthermore, the crystallization system 10A7 according to the seventh modified example of the crystallization system 10A of the first embodiment can be regarded as a crystallization method in which the crystallization system 10A5 according to the fifth modified example of the crystallization system 10A of the first embodiment or the crystallization system 10A6 according to the sixth modified example of the crystallization system 10A of the first embodiment is provided with extension tubes 12 extending radially outward from the multiple liquid supply units 50b, and in the second liquid supply step, the second reaction liquid L2 is supplied from the tip of the extension tube 12. This crystallization method can achieve the same effects as the crystallization system 10A7 according to the seventh modified example of the crystallization system 10A of the first embodiment and the crystallization system 10A8 according to the eighth modified example.

[0095] The above has described in detail an embodiment of the present invention and its modified examples with reference to the drawings, but the specific configurations are not limited to the embodiment and its modified examples, and also include designs and the like within the scope of the gist of the present invention, and combinations of the embodiment and modified examples.

[0096] For example, in the above embodiment, the product is obtained by mixing two types of reaction liquids, the first reaction liquid L1 and the second reaction liquid L2, but three or more types of reaction liquids may be mixed. [Explanation of symbols]

[0097] 1 Reaction vessel 2 Cylindrical part 3 Rotation Axis 4. Crystallizer 5a entrance 5b Liquid supply part 6 Outlet 8 Disc Section 9, h hole 10A, 10B, 10C, 10A1, 10A2, 10A3, 10A4, 10A5, 10A6, 10A7, 10A8 Crystallization Systems 22, 23, 24 Piping 30 Circulation Pump 31 Second circulation pump Po circulation pipe Pp bent part Po1, Po2, Po3, Po4, Po5, Po6 straight pipe section C, C1, C2, C3, C4, C5 curved pipe sections W, Wa, Wb, Wc, Wd, We, Wf, Wg, Wh

Claims

1. a crystallizer that mixes a plurality of raw material solutions to generate particles derived from the raw materials in the plurality of raw material solutions; a circulation pipe that causes the slurry containing the particles discharged from the discharge port of the crystallizer to flow and circulates the slurry from the inlet of the crystallizer into the crystallizer; a circulation pump that circulates the slurry between the crystallizer and the circulation line; A crystallization system characterized in that the circulation pipeline has a meandering bent portion.

2. 2. The crystallization system according to claim 1, wherein the inner diameter of the circulation pipeline is constant.

3. 3. The crystallization system according to claim 1, wherein a plurality of the bent portions are provided.

4. 4. The crystallization system according to claim 1, wherein at least a portion of the bent portion is provided inside a temperature adjustment tank.

5. 5. The crystallization system according to claim 1, wherein the bending section is composed of a plurality of separable straight pipe sections and a plurality of separable curved pipe sections.

6. The crystallizer includes an agitator blade having a plurality of holes penetrating in a radial direction and rotatable around a central axis; a cylindrical reaction vessel with a bottom that can accommodate the stirring blade concentrically therein; an inlet provided in the reaction tank and capable of supplying a first reaction solution into the reaction tank; a liquid supply unit provided on the stirring blade and capable of supplying a second reaction liquid into the reaction tank; The crystallization system according to any one of claims 1 to 5, comprising:

7. The stirring blade comprises a cylindrical portion, a disk-shaped portion having an outer peripheral portion fixed to an inner peripheral surface of the cylindrical portion, and a rotation shaft extending upward from the center of the disk portion along the central axis in a plan view, the second reaction solution can flow through the interior of the disk portion and the rotating shaft, The crystallization system according to claim 6, wherein the liquid supply section is provided on the outer edge of the disk section.

8. The crystallization system according to claim 7, wherein the liquid supply section opens downward.

9. The crystallization system according to claim 7, wherein the liquid supply portion opens radially outward and penetrates the cylindrical portion.

10. a crystallization step of mixing a plurality of raw material solutions and growing particles derived from the raw materials in the plurality of raw material solutions in a crystallizer; a circulation step of circulating the slurry containing the particles discharged from the discharge port of the crystallizer to the inlet of the crystallizer by flowing the slurry through a circulation pipeline having a serpentine bend.

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