Fluidized bed classification system

Abstract

The classification system using a fluidized bed according to the present invention includes a fluidized bed classifier that receives powder containing particles of different sizes, fluidizes the powder in a fluidizing gas, and discharges the coarse powder through a coarse powder outlet at a lower portion thereof, and a cyclone that communicates with an upper portion of the fluidized bed classifier and discharges fine powder contained in the fluidizing gas transferred from the fluidized bed classifier through a fine powder outlet at a lower portion thereof, and an internal structure that is located in the fluidized bed of the fluidized bed classifier and reduces the size of bubbles in the fluidizing gas.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0149249 filed on November 2, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a classification system using a fluidized bed for separating powder according to particle size, and more particularly to a classification system capable of separating powder according to particle size by adjusting differences in particle flow and scattering characteristics due to particle size. [Background technology]

[0003] In various fields, work is carried out to separate the particle size of powder, which is an aggregate of small particles. Classifiers are used as devices for separating the particle size of the powder, and conventionally, mechanical classifiers and air flow classifiers have been used.

[0004] The mechanical classifier uses a mechanical part such as a sieve having a mesh. In this case, only particles smaller than the size of the mesh are allowed to pass through the sieve to select particle size. However, the more fine the particles are, the more frequently the sieve becomes clogged, resulting in poor classification performance or difficulty in operation.

[0005] In addition, air classifiers separate particle sizes by contacting powder particles with gas, and there is a problem that classification performance decreases when the residence time of particles in the device is short and a processing volume greater than the saturation carrying capacity of the gas is required. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above-mentioned problems of the conventional technology, and has an object to provide a system that can continuously separate powder particle sizes without clogging by reducing the size of bubbles in a fluidizing gas to adjust the flow and scattering characteristics of particles according to particle size when separating powder particle sizes using a fluidized bed classifier and a cyclone. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a classification system using a fluidized bed, which includes a fluidized bed classifier that is supplied with powder containing particles of different sizes, fluidizes the powder in a fluidizing gas, and discharges the coarse powder through a coarse powder outlet at a lower portion, and a cyclone that is connected to an upper portion of the fluidized bed classifier and collects and discharges fine powder contained in the fluidizing gas transferred from the fluidized bed classifier to a fine powder outlet at a lower portion, and includes an internal structure that is located in the fluidized bed of the fluidized bed classifier and reduces the size of bubbles in the fluidizing gas. Effect of the Invention

[0008] According to the classification system of the present invention, an internal structure for controlling the size of bubbles of the fluidizing gas is formed in the fluidized bed inside the fluidized bed classifier, and the flow and scattering characteristics of particles according to particle size are controlled, making it possible to continuously separate powder particle sizes without clogging. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows a classification system using a fluidized bed according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram specifically illustrating an internal structure according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram specifically illustrating an internal structure according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram specifically illustrating an internal structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The terms and words used in the description of the present invention and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0011] In order to facilitate understanding of the present invention, the present invention will now be described in more detail with reference to the following FIGS. 1 to 4. FIG.

[0012] According to the present invention, there is provided a classification system using a fluidized bed, which includes a fluidized bed classifier 10 to which powder containing particles of different sizes is supplied, which fluidizes the powder in a fluidizing gas, and which discharges the coarse powder through a coarse powder outlet 15 at the bottom, and a cyclone 30 connected to an upper part of the fluidized bed classifier 10 and which collects and discharges fine powder contained in the fluidizing gas transferred from the fluidized bed classifier 10 to a fine powder outlet 31 at the bottom, and an internal structure 20 located in the fluidized bed 16 of the fluidized bed classifier 10 and which reduces the size of bubbles 18 of the fluidizing gas.

[0013] In the past, work has been carried out in various fields to separate the particle size of powder, which is an aggregate of small particles. Classifiers have been used as devices for separating the particle size of the powder, and conventionally mechanical classifiers and air flow classifiers have been used.

[0014] The mechanical classifier uses a mechanical part such as a sieve having a mesh. In this case, only particles smaller than the size of the mesh are allowed to pass through the sieve to select particle size. However, the more fine the particles are, the more frequently the sieve becomes clogged, resulting in poor classification performance or difficulty in operation.

[0015] In addition, air classifiers separate particle sizes by contacting powder particles with gas, and there is a problem that classification performance decreases when the residence time of particles in the device is short and a processing volume greater than the saturation carrying capacity of the gas is required.

[0016] In contrast, the present invention aims to provide a classification system that uses a fluidized bed, which can ensure the throughput and sorting capacity, which are indicators of classification performance, by adjusting the particle flow and scattering characteristics according to particle size and selecting the particle size of the powder, and which does not use a sieve and therefore does not have the problem of performance degradation due to clogging.

[0017] According to an embodiment of the present invention, the fluidized bed classifier 10 may be continuously supplied with powders containing particles of different sizes for particle size classification. Here, the powders may include fine powders and coarse powders. For example, the fine powders may mean particles having a diameter of 150 μm or less, and the coarse powders may mean particles having a diameter of more than 150 μm to 850 μm. Meanwhile, the distinction between the fine powders and the coarse powders may not be an absolute matter. For example, the powders discharged through the coarse powder outlet 15 provided at the bottom of the fluidized bed classifier 10 may be classified as coarse powders, and the powders discharged through the fine powder outlet 31 at the top of the fluidized bed classifier 10 may be classified as fine powders. In this case, the boundary between the coarse powders and the fine powders may be determined according to the operating conditions of the fluidizing gas.

[0018] The powder may be supplied to the inside of the fluidized bed classifier 10 through a particle inlet 11 provided on a side of the fluidized bed classifier 10. The particle inlet 11 may have a downward inclination toward the fluidized bed classifier 10, so that the powder may be continuously supplied to the fluidized bed classifier 10.

[0019] The powder supplied to the fluidized bed classifier 10 is accumulated on the upper part of the gas dispersion plate 14 installed at the lower part of the fluidized bed classifier 10, and a fluidized bed 16 is formed by the fluidizing gas moving upward through the gas chamber 13 below the gas dispersion plate 14.

[0020] According to an embodiment of the present invention, a fluidization gas injection pipe 12 may be installed at the bottom of the fluidized bed classifier 10. A fluidization gas may flow into a lower gas chamber 13 of the fluidized bed classifier 10 through the fluidization gas injection pipe 12, and move upward from the gas chamber 13 through a gas dispersion plate 14 to fluidize the powder in the fluidized bed 16. Here, the type of the fluidization gas is not particularly limited, and various gases such as compressed air or oxygen may be used. When particles contained in the powder should not come into contact with air, the fluidization may be performed using an inert gas such as nitrogen or helium.

[0021] The fluidizing gas can move from the top of the fluidized bed classifier 10 to the cyclone 30, and can be discharged to the top of the cyclone 30 and circulated to the fluidizing gas injection pipe 12 for reuse.

[0022] According to an embodiment of the present invention, the fluidized bed classifier 10 may include an internal structure 20 provided in the fluidized bed 16. The internal structure 20 is located in the fluidized bed 16 in the fluidized bed classifier 10 to reduce the size of bubbles 18 of the fluidizing gas rising, and by reducing the size of the bubbles 18 of the fluidizing gas, the scattering characteristics of particles can be controlled, allowing continuous classification without using a sieve, and classification performance can be improved without clogging when using a sieve.

[0023] The internal structure 20 may include a frame 21 corresponding to the inner circumferential surface of the fluidized bed classifier 10 , and wires 22 forming a lattice structure inside the frame 21 .

[0024] The frame 21 can be closely fixed to the inner wall of the fluidized bed classifier 10 corresponding to the inner peripheral surface of the fluidized bed classifier 10, and at the same time, can fix the wire 22 formed in a lattice structure formed inside the frame 21.

[0025] The wires 22 may be formed in a polygonal lattice structure. Specifically, the wires 22 may be suitably formed in a polygonal shape, such as a triangle, a square, a pentagon, or a hexagon, so as to be advantageous in reducing the size of the bubbles 18 within the frame 21.

[0026] The diameter of the wire 22 may be 0.1% or more, 0.5% or more, or 0.7% or more, and 1%, 1.5%, or less, or 2% or less of the diameter of the fluidized bed classifier 10. By forming a lattice structure in the internal structure 20 with the wire 22 having a diameter within the above range, it is possible to adjust the particle scattering characteristics without impeding the flow of particles, and improve the ability to separate fine and coarse powders within the powder.

[0027] The opening area of ​​the internal structure 20 may be 80% or more, 83% or more, or 85% or more, and 90% or less, 92% or less, or 95% or less of the cross-sectional area of ​​the fluidized bed classifier 10. By designing the opening area of ​​the internal structure 20 within the above range, the size of the bubbles 18 can be reduced without affecting the flow of particles, and the linear velocity of the fluidizing gas can be appropriately controlled to prevent a sudden increase in the amount of particles scattering, thereby improving the ability to separate by particle size.

[0028] The internal structure 20 may be installed in a plurality at predetermined intervals along the height direction of the fluidized bed classifier 10. For example, the number of the internal structure 20 may be appropriately selected to adjust the size of the bubbles 18 required according to the size of the particles in the powder, and as a specific example, 4 to 10 internal structures 20 may be installed.

[0029] When a plurality of internal structures 20 are installed, the distance between adjacent internal structures 20 may be 0.05 m or more, 0.1 m or more, or 0.15 m or more, and 0.2 m or less, or 0.25 m or less. By adjusting the distance between the internal structures 20 within the above range, the effect of reducing the size of the bubbles 18 can be increased, and in particular, the effect of reducing the scattering of coarse powder, which is a relatively large particle, can be increased.

[0030] The uppermost internal structure 20 among the plurality of internal structures 20 may be installed at a position corresponding to the height of the fluidized bed surface 17. Specifically, the size of the air bubbles 18 has a significant effect on the scattering of coarse particles, which are relatively large particles, and when the air bubbles 18 are large, there is a problem that the coarse particles are scattered and discharged to the upper part of the fluidized bed classifier 10, which may result in a decrease in classification performance. Therefore, by forming a plurality of internal structures 20 in the fluidized bed 16 and installing the uppermost internal structure 20 among the plurality of internal structures 20 near the height of the fluidized bed surface 17, it is possible to adjust the scattering characteristics of the particles by finally reducing the size of the air bubbles 18 just before the particles are ejected by the air bubbles 18 near the fluidized bed surface 17.

[0031] The plurality of internal structures 20 may be installed in a form rotated by 30° or more, 35° or more, or 40° or more, and 50° or less, or 55° or less with respect to the adjacent internal structures 20. For example, the plurality of internal structures 20 may be installed in a cross arrangement with an internal structure 20 as shown in Fig. 4(a) below and an internal structure 20 as shown in Fig. 4(b) which is obtained by rotating the internal structure 20 as shown in Fig. 4(a) 45° to the right, and in this case, the AB cross section may be as shown in Fig. 4(c) below. When a plurality of internal structures 20 are installed in this manner, the size of the bubbles 18 can be effectively reduced without a sudden increase in the linear velocity of the fluidizing gas.

[0032] According to an embodiment of the present invention, a coarse powder discharge port 15 may be formed at a lower portion of the fluidized bed classifier 10. Specifically, the coarse powder discharge port 15 may be installed at a lower portion of the fluidized bed classifier 10, for example, at a lower portion of a fluidized bed 16 formed in the powder, and the coarse powder may be continuously discharged and separated through the coarse powder discharge port 15.

[0033] The coarse powder discharge port 15 may be formed with a downward incline from the fluidized bed classifier 10, so that the coarse powder in the fluidized bed 16 may be continuously discharged to the outside of the fluidized bed classifier 10.

[0034] According to an embodiment of the present invention, the cyclone 30 may be included to separate fine powder from the powder. Specifically, the cyclone 30 may be formed in communication with an upper portion of the fluidized bed classifier 10, and a fluidizing gas may be introduced from the fluidized bed classifier 10, and the fluidizing gas introduced from the fluidized bed classifier 10 may include fine powder scattered together with the fluidizing gas.

[0035] The cyclone 30 may have a fine powder outlet 31 formed at a lower portion thereof. Specifically, the fine powder flowing in together with the fluidizing gas from the fluidized bed classifier 10 can be separated and discharged to the lower portion of the cyclone 30 through the fine powder outlet 31.

[0036] According to an embodiment of the present invention, the fluidizing gas discharged to the upper part of the cyclone 30 passes through a dust collector 40 to remove further solid particles, and then is transferred through a gas circulation pipe 41 and merges with the fluidizing gas injection pipe 12 to be circulated to the fluidized bed classifier 10. By removing fine particles that may remain in the fluidizing gas in the dust collector 40, separation of fine particles through the coarse particle discharge port 15 formed at the lower part of the fluidized bed classifier 10 can be prevented when the fluidizing gas is circulated and supplied to the lower part of the fluidized bed classifier 10 for reuse.

[0037] The scattering of particles in the fluidized bed 16 is mainly caused by the destruction of bubbles 18 at the fluidized bed surface 17, and the amount of particles retained can be exponentially decreased as the ratio of particles converted to a downward flow increases as the particle rises from the fluidized bed surface 17. The minimum height (Transportation Disengaging Height, TDH) at which the amount of particles retained becomes constant regardless of the height from the height of the fluidized bed surface 17 can be changed depending on the size of the bubbles formed from the fluidizing gas. In the present invention, an internal structure 20 is formed in the fluidized bed 16, and the size of the bubbles 18 is controlled to adjust the TDH without disturbing the flow of particles by adjusting the shape, number and arrangement of the internal structure 20, thereby achieving excellent sorting ability and high throughput.

[0038] The above description is merely illustrative of the technical idea of ​​the present invention, and various modifications and variations are possible within the scope of the essential characteristics of the present invention, if one has ordinary knowledge in the technical field to which the present invention belongs. Therefore, the embodiments disclosed in the present invention are for the purpose of explanation, not for the purpose of limiting the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments. The scope of protection of the present invention should be interpreted according to the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

[0039] The present invention will be described in more detail with reference to the following examples. However, the following examples are merely for the purpose of illustrating the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the scope and technical idea of ​​the present invention, and the scope of the present invention is not limited to these examples.

[0040] Working Example Example 1 The particle size of the powder was selected using a classification system using a fluidized bed as shown in Figure 1 below.

[0041] Specifically, powder containing particles of different sizes was fed through particle inlet 11 of fluidized bed classifier 10, and fluidizing gas transferred through fluidizing gas injection pipe 12 was allowed to flow into gas chamber 13, after which the powder was fluidized using the fluidizing gas that passed through gas dispersion plate 14 and moved to the upper part. The above powder was similarly used in the following Examples 2 to 5 and Comparative Examples 1 and 2.

[0042] Six internal structures 20 were installed in the fluidized bed 16 in the fluidized bed classifier 10 along the height direction of the fluidized bed classifier 10. The diameter of the wires 22 of the internal structures 20 was adjusted to 2% of the diameter of the fluidized bed classifier 10, and the interval between each of the internal structures 20 was adjusted to 0.2 m. In addition, the wires 22 of each of the internal structures 20 were formed in a rectangular lattice structure as shown in the left diagram of FIG. 3 below, and the open area was designed to be 85% of the cross-sectional area of ​​the fluidized bed classifier 10, and the uppermost internal structure 20 among the six internal structures 20 was installed near the height of the fluidized bed surface 17.

[0043] The coarse powder was discharged through a coarse powder outlet 15 installed at the bottom of the fluidized bed classifier 10, and the fluidizing gas moving to the top of the fluidized bed classifier 10 and the fine powder scattered together with the fluidizing gas were supplied to a cyclone 30.

[0044] In the cyclone 30, fine powder is separated through a fine powder outlet 31 at the bottom, and the fluidizing gas is discharged to the top to separate solid particles in a dust collector 40, and then the gas is merged with the fluidizing gas injection pipe 12 through a gas circulation pipe 41 and circulated to the fluidized bed classifier 10.

[0045] In this case, the separation ability between the fine powder and the coarse powder was excellent, continuous separation by particle size was possible, and a high throughput per hour was demonstrated.

[0046] Example 2 The particle size of the powder was selected using a classification system using a fluidized bed as shown in Figure 1 below.

[0047] Specifically, powder containing particles of different sizes is fed through the particle inlet 11 of the fluidized bed classifier 10, and the fluidizing gas transported through the fluidizing gas injection pipe 12 is allowed to flow into the gas chamber 13. The powder is then passed through the gas dispersion plate 14, and the fluidizing gas moving to the top is used to fluidize the powder.

[0048] Six internal structures 20 were installed in the fluidized bed 16 in the fluidized bed classifier 10 along the height direction of the fluidized bed classifier 10. The diameter of the wires 22 of the internal structures 20 was adjusted to 1.5% of the diameter of the fluidized bed classifier 10, and the interval between each of the internal structures 20 was adjusted to 0.15 m. In addition, the wires 22 of each of the internal structures 20 were formed in a triangular lattice structure as shown in the right diagram of FIG. 3 below, and the open area was designed to be 80% of the cross-sectional area of ​​the fluidized bed classifier 10, and the uppermost internal structure 20 among the six internal structures 20 was installed near the height of the fluidized bed surface 17.

[0049] The coarse powder was discharged through a coarse powder outlet 15 installed at the bottom of the fluidized bed classifier 10, and the fluidizing gas moving to the top of the fluidized bed classifier 10 and the fine powder scattered together with the fluidizing gas were supplied to a cyclone 30.

[0050] In the cyclone 30, fine powder is separated through a fine powder outlet 31 at the bottom, and the fluidizing gas is discharged to the top. After the solid particles are separated in a dust collector 40, the gas is merged with the fluidizing gas injection pipe 12 through a gas circulation pipe 41 and circulated to the fluidized bed classifier 10.

[0051] In this case, the separation ability between fine and coarse powders was excellent, similar to that of Example 1, and continuous separation by particle size was possible, and the throughput per hour was high.

[0052] Example 3 The particle size of the powder was selected using a classification system using a fluidized bed as shown in Figure 1 below.

[0053] Specifically, powder containing particles of different sizes is fed through the particle inlet 11 of the fluidized bed classifier 10, and the fluidizing gas transported through the fluidizing gas injection pipe 12 is allowed to flow into the gas chamber 13. The powder is then passed through the gas dispersion plate 14, and the fluidizing gas moving to the top is used to fluidize the powder.

[0054] Six internal structures 20 were installed in the fluidized bed 16 in the fluidized bed classifier 10 along the height direction of the fluidized bed classifier 10. The diameter of the wire 22 of the internal structure 20 was adjusted to 1.8% of the diameter of the fluidized bed classifier 10, and the interval between each of the internal structures 20 was adjusted to 0.1 m. The wire 22 of each of the internal structures 20 was formed in a rectangular lattice structure as shown in the left side of FIG. 3 below, and the open area was designed to be 80% of the cross-sectional area of ​​the fluidized bed classifier 10. The six internal structures 20 were arranged in a cross-arrangement with the internal structure 20 as shown in FIG. 4(a) below and the internal structure 20 as shown in FIG. 4(b) obtained by rotating the internal structure 20 as shown in FIG. 4(a) 45° to the right, and the uppermost internal structure 20 was installed near the height of the surface 17 of the fluidized bed.

[0055] The coarse powder was discharged through a coarse powder outlet 15 installed at the bottom of the fluidized bed classifier 10, and the fluidizing gas moving to the top of the fluidized bed classifier 10 and the fine powder scattered together with the fluidizing gas were supplied to a cyclone 30.

[0056] In the cyclone 30, fine powder is separated through a fine powder outlet 31 at the bottom, and the fluidizing gas is discharged to the top. After the solid particles are separated in a dust collector 40, the gas is merged with the fluidizing gas injection pipe 12 through a gas circulation pipe 41 and circulated to the fluidized bed classifier 10.

[0057] In this case, the separation ability between fine and coarse powders was excellent, similar to that of Examples 1 and 2, and continuous separation by particle size was possible, and the throughput per hour was high.

[0058] Example 4 The particle size of the powder was selected using a classification system using a fluidized bed as shown in Figure 1 below.

[0059] Specifically, powder containing particles of different sizes is fed through the particle inlet 11 of the fluidized bed classifier 10, and the fluidizing gas transported through the fluidizing gas injection pipe 12 is allowed to flow into the gas chamber 13. The powder is then passed through the gas dispersion plate 14, and the fluidizing gas moving to the top is used to fluidize the powder.

[0060] Four internal structures 20 were installed in the fluidized bed 16 in the fluidized bed classifier 10 along the height direction of the fluidized bed classifier 10. The diameter of the wires 22 of the internal structures 20 was adjusted to 3.5% of the diameter of the fluidized bed classifier 10, and the interval between each of the internal structures 20 was adjusted to 0.3 m. In addition, the wires 22 of each of the internal structures 20 were formed in a rectangular lattice structure as shown in the left diagram of FIG. 3 below, and the open area was designed to be 75% of the cross-sectional area of ​​the fluidized bed classifier 10, and the uppermost internal structure 20 among the four internal structures 20 was installed near the height of the fluidized bed surface 17.

[0061] Coarse powder was discharged through a coarse powder outlet 15 installed at the bottom of the fluidized bed classifier 10, and the fluidizing gas moving to the top of the fluidized bed classifier 10 and the fine powder scattered together with the fluidizing gas were supplied to a cyclone 30.

[0062] In the cyclone 30, fine powder is separated through a fine powder outlet 31 at the bottom, and the fluidizing gas is discharged to the top to separate solid particles in a dust collector 40, and then the gas is merged with the fluidizing gas injection pipe 12 through a gas circulation pipe 41 and circulated to the fluidized bed classifier 10.

[0063] In this case, the gap between the internal structures 20 was wide, so that the size of the bubbles could not be appropriately controlled, and the narrow open area of ​​the internal structures 20 caused the flow of particles to be impeded, so that the linear velocity of the fluidizing gas was partially increased, and the scattering behavior of the coarse powder was intensified, and the separation ability between the fine powder and the coarse powder was somewhat lower than that of Examples 1 to 3.

[0064] Example 5 The particle size of the powder was selected using a classification system using a fluidized bed as shown in Figure 1 below.

[0065] Specifically, powder containing particles of different sizes is fed through the particle inlet 11 of the fluidized bed classifier 10, and the fluidizing gas transported through the fluidizing gas injection pipe 12 is allowed to flow into the gas chamber 13. The powder is then passed through the gas dispersion plate 14, and the fluidizing gas moving to the top is used to fluidize the powder.

[0066] Three internal structures 20 were installed in the fluidized bed 16 in the fluidized bed classifier 10 along the height direction of the fluidized bed classifier 10. The diameter of the wires 22 of the internal structures 20 was adjusted to 5% of the diameter of the fluidized bed classifier 10, and the interval between each of the internal structures 20 was adjusted to 0.3 m. In addition, the wires 22 of each of the internal structures 20 were formed in a rectangular lattice structure as shown in the left diagram of FIG. 3 below, and the open area was designed to be 70% of the cross-sectional area of ​​the fluidized bed classifier 10, and the uppermost internal structure 20 among the six internal structures 20 was installed at a height 0.3 m lower than the height of the fluidized bed surface 17.

[0067] Coarse powder was discharged through a coarse powder outlet 15 installed at the bottom of the fluidized bed classifier 10, and the fluidizing gas moving to the top of the fluidized bed classifier 10 and the fine powder scattered together with the fluidizing gas were supplied to a cyclone 30.

[0068] In the cyclone 30, fine powder is separated through a fine powder outlet 31 at the bottom, and the fluidizing gas is discharged to the top to separate solid particles in a dust collector 40, and then the gas is merged with the fluidizing gas injection pipe 12 through a gas circulation pipe 41 and circulated to the fluidized bed classifier 10.

[0069] In this case, the spacing between the internal structures 20 was wide, the position of the uppermost internal structure 20 was not appropriate, the size of the bubbles 18 of the fluidizing gas was not properly controlled, the narrow open area of ​​the internal structure 20 caused the flow of particles to be obstructed, the linear velocity of the fluidizing gas was partially increased, and the scattering behavior of the coarse powder was intensified, and the separation ability between the fine powder and the coarse powder was very low compared to Examples 1 to 4.

[0070] Comparative Example Comparative Example 1 Powder containing particles of different sizes was fed through the particle inlet 11 of the fluidized bed classifier 10, and the fluidizing gas transported through the fluidizing gas injection pipe 12 was allowed to flow into the gas chamber 13. The powder was then passed through the gas dispersion plate 14 and fluidized by the fluidizing gas moving to the top.

[0071] Coarse powder was discharged through a coarse powder outlet 15 installed at the bottom of the fluidized bed classifier 10, and the fluidizing gas moving to the top of the fluidized bed classifier 10 and the fine powder scattered together with the fluidizing gas were supplied to a cyclone 30.

[0072] In the cyclone 30, fine powder is separated through a fine powder outlet 31 at the bottom, and the fluidizing gas is discharged to the top to separate solid particles in a dust collector 40, and then the gas is merged with the fluidizing gas injection pipe 12 through a gas circulation pipe 41 and circulated to the fluidized bed classifier 10.

[0073] In this case, the size of the bubbles 18 of the fluidizing gas was not controlled due to the absence of the internal structure 20, and the separation ability between the fine powder and the coarse powder was very low compared to Examples 1 to 5.

[0074] Comparative Example 2 The same method as in Example 1 was carried out, except that the internal structure 20 was installed not in the fluidized bed 16 but in an upper region higher than the height of the fluidized bed surface 17.

[0075] In this case, the internal structure 20 was unable to affect the control of the size of the bubbles 18, and the effect of Example 1 could not be achieved, and therefore the separation ability between the fine and coarse powders was very low, similar to that of Comparative Example 1.

Claims

1. a fluidized bed classifier that receives powder containing particles of different sizes, fluidizes the powder in a fluidizing gas, and discharges the coarse powder through a coarse powder discharge port at a lower portion; a cyclone communicating with an upper portion of the fluidized bed classifier and collecting and discharging fine particles contained in the fluidizing gas transferred from the fluidized bed classifier at a fine particle outlet at a lower portion thereof; an internal structure located in the fluidized bed of the fluidized bed classifier and configured to reduce the size of bubbles of a fluidizing gas; The internal structure includes a frame corresponding to an inner peripheral surface of the fluidized bed classifier, and wires forming a lattice structure inside the frame, The internal structure is installed in a plurality of pieces at predetermined intervals along the height direction of the fluidized bed classifier, The internal structure is spaced from adjacent internal structures by 0.05 m to 0.25 m; the diameter of the wire is 0.1% to 2% of the diameter of the fluidized bed classifier; A classification system using a fluidized bed, wherein the open area of ​​the internal structure is 80% to 95% of the cross-sectional area of ​​the fluidized bed classifier.

2. 10. The fluidized bed classification system of claim 1, wherein the wires are formed into a polygonal lattice structure.

3. 2. The classification system using a fluidized bed according to claim 1, wherein the uppermost internal structure among the plurality of internal structures is installed at a position corresponding to a surface height of the fluidized bed.

4. 2. The system of claim 1, wherein the plurality of internal structures are rotated by 30 degrees to 55 degrees with respect to adjacent internal structures.

5. 2. The classification system using a fluidized bed according to claim 1, wherein the fluidizing gas is supplied through a fluidizing gas injection pipe installed at a lower part of the fluidized bed classifier, moves upward while fluidizing the powder, moves from an upper part of the fluidized bed classifier to a cyclone, is discharged to an upper part of the cyclone, and circulates to the fluidizing gas injection pipe.

6. 6. The classification system using a fluidized bed according to claim 5, wherein the fluidizing gas discharged from the upper part of the cyclone passes through a dust collector, is transferred to a gas circulation pipe, and merges with the fluidizing gas injection pipe to be circulated to the fluidized bed classifier.

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