JP2548519B2 - Fluidized bed classifier - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed classifier that separates powders and granules that need to be handled as raw materials or products in the kiln industry, metal smelting industry, etc. according to the particle size.

[0002]

2. Description of the Related Art Conventional classifiers are roughly classified into sieves and wind classifiers. The size of the sieve is determined by the size of the mesh. Fine-grained items tend to be clogged. Practically, it is suitable for classification with a particle size of 1 mm or more. The wind classifier is represented by a cyclone. Practically, it is suitable for classification of particles having a particle size of 100 μm or less. Intermediate particle size, 100 μm to 1 mm
There is a problem in classification efficiency and maintenance, and is not practical.

Japanese Unexamined Patent Publication No. 63-258685 discloses a prior art of an apparatus for classifying powder by utilizing a fluidized bed. In this prior art, a fluidized bed is formed while applying vibration, and classification is performed at a level of several microns or even submicrons. This prior art does not cover the larger particle size range of 100 μm to 1 mm.

[0004]

The necessity of classification with a particle size of about 100 μm to 1 mm is the reason why the flow of a granular raw material as disclosed in Japanese Patent Application Laid-Open No. 4-108642 by the applicant of the present application is necessary. It occurs when classifying the dust contained in the exhaust gas from the layer firing apparatus. Fine particles of calcium carbonate having a size of 100 μm or less generated when firing lime can be used as a desulfurization material for a flue gas desulfurization device. 100 μm from this lime fluidized bed calciner
Since dust in which coarse particles having the above-mentioned large particle size are mixed is generated, effective use as a by-product is not possible simply by collecting dust.

In the prior art as disclosed in Japanese Patent Laid-Open No. 63-258685, the flow velocity of the gas supplied to form the fluidized bed is relatively low, and the formation of the fluidized bed is promoted by the vibration applied from the outside. This enables classification with a fine particle size. With such a configuration, coarse particles having a larger particle size cannot be fluidized and settle and accumulate at the bottom. When coarse particles settle and accumulate, it becomes difficult to form a fluidized bed, and therefore it is not suitable for classification of powder particles containing coarse particles. Further, when the water content in the raw material increases, the fine powder to be classified is granulated in the fluidized bed, and the classification efficiency decreases. Further, problems such as adhesion of the wet raw material to the inner wall surface and clogging of the discharge chute occur.

The object of the invention is in particular between 100 μm and 1 mm.
(EN) A fluidized bed classifier capable of efficiently classifying particles having an intermediate particle size.

Still another object of the present invention is to provide a fluidized bed classifier capable of removing only the coarse powder while preventing the fine powder from being mixed into the coarse powder to be discharged as much as possible.

[0008]

MEANS FOR SOLVING THE PROBLEMS The present invention comprises a container, a raw material charging means for charging a granular raw material into the container, and a gas blown from below the dispersion plate into the raw material charged into the container,
A fluidized bed forming means for forming a fluidized bed, a flow rate adjusting means for adjusting a flow velocity of gas forming the fluidized bed, and a space provided immediately adjacent to a dispersion plate in a container in which the fluidized bed is formed. A fluidized bed classifier comprising: a cross-sectional reduction member capable of adjusting a cross-sectional area of a portion; a particle separating means for separating particles staying in the formed fluidized bed; and particles scattered from the fluidized bed. Is.

Further, according to the present invention, the classified coarse powder is discharged from the lower part, which is connected to the discharge port formed on the side of the container and extends in the vertical direction, and the classified coarse powder is discharged from the lower part. In between, a discharge chute having a plurality of supply ports formed at intervals in the longitudinal direction, an airtight discharge means provided in the lower part of the discharge chute, and an auxiliary gas for classification are separated in the longitudinal direction of the discharge chute. The auxiliary gas supply source for classification, which is respectively supplied from the plurality of supply ports formed by opening, the speed of the auxiliary gas for classification is selected to be not higher than the superficial velocity u0 of the freeboard of the container at the discharge port. It is characterized by

According to the present invention, the velocity of the auxiliary gas for classification is
At the outlet, a value is selected that exceeds the fluidization start speed umf of the coarse powder to be classified.

The present invention is also characterized in that the speed of the auxiliary gas for classification in the discharge chute just above the lowermost supply port is selected to be less than the fluidization start speed umf of the coarse powder to be classified.

[0012]

[0013]

[0014]

[0015]

[0016]

According to the present invention, a powdery raw material is charged into the empty column, and gas is blown from below to form a fluidized bed.
By adjusting the flow rate of the gas by the flow rate adjusting means, it is possible to adjust the particle size for separating the particles staying in the formed fluidized bed and the particles scattered from the fluidized bed. This particle size can be easily adjusted within the range of 100 μm to 1 mm, and efficient classification can be performed.

According to the invention, the auxiliary gas for classification can be blown into the discharge chute which is connected to the discharge port formed on the side of the container and discharges the classified coarse powder. At the discharge port, the velocity of the auxiliary gas for classification is selected to be equal to or lower than the superficial velocity of the freeboard of the container, so that the coarse powder in the discharge chute remains in the discharge chute and does not return to the container.

Further, the speed of the auxiliary gas for classification is selected to be a value higher than the fluidization start speed of the coarse powder to be classified, whereby the proportion of fine powder having a particle size of the classification or less mixed in the discharge chute is reduced, and the classification efficiency is improved. Is improved.

Further, the auxiliary gas for classification is blown from a plurality of blowing openings which are spaced in the longitudinal direction of the discharge chute,
The speed is selected to be less than the fluidization start speed of the coarse powder to be classified just above the bottommost blowing port. Therefore, the entire discharge chute is not fluidized, and the coarse powder in the discharge chute remains in the discharge chute and does not return to the container.

[0020]

[0021]

[0022]

Furthermore, according to the present invention, since the partial cross-sectional area of the superficial column in which the fluidized bed is formed is reduced, the flow velocity for forming the fluidized bed is set to be smaller than the flow velocity for transporting particles scattered from the fluidized bed. Can also be large. As a result, a wide range of particles including coarse particles can be easily fluidized, and the classified particle diameter can be efficiently changed without causing fluidization failure.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a fluidized bed classifier which is the premise of the present invention. The fluidized bed classifier 1 is composed of a wind box 2, a porous dispersion plate 3, and an empty column 4 which is a cylindrical container having a vertical axis. Air is supplied to the wind box 2 from a blower 5 via a flow rate adjusting damper 6 and a blow port 7. A large number of through holes are formed in the vertical direction in the porous dispersion plate 3. The air supplied to the wind box 2 passes through the through holes of the porous dispersion plate 3 and blows up into the empty tower 4 at a flow rate ub.

Above the porous dispersion plate 3, a raw material in the form of powder or granules is fed through a raw material feeding chute 8. The raw material in the form of powder or granules is fluidized by the air having a flow rate ub passing through the porous dispersion plate 3 to form the fluidized bed 9. In the space above the fluidized bed 9 in the container 4, the superficial velocity u0
Air rises at the flow velocity of the
Emitted from. The discharged air flow passes through the cyclone 11 and the bag filter 12, and the contained fine powdery raw material is removed. The fine powdery raw materials thus removed are put together by the screw conveyor 13.

A discharge chute 14 is provided above the fluidized bed 9, or a bottom discharge chute 15 is provided below the fluidized bed 9 and directly above the porous dispersion plate 3.
In some cases, only one of these is provided. The raw material charging chute 8, the discharging chute 14 or the bottom discharging chute 15 is provided with airtight dampers 16, 17 and 18, respectively, so that the inside of the empty column 4 is hermetically sealed to perform the charging and discharging of the granular material. it can. Such airtight dampers 16, 17, and 18 are realized by airtight discharge means such as a rotary damper, an electric damper, and a material seal. Since the inside of the empty column 4 is kept airtight, the pressure in the empty column 4 can be increased. Although the dispersion plate of this configuration shows a porous type, it goes without saying that it may be a cap type.

From the discharge chute 14 or the bottom discharge chute 15, the coarse particles contained in the raw material are taken out. The fine powder collected by the cyclone 11 and the bag filter 12 is collected in the screw conveyor 13 via valves 19 and 20, respectively. That is,
The coarse particles of the raw material in the raw material charging chute 8 are separated from the discharge chute 14 or the bottom discharge chute 15 and discharged, and the fine powder is separated and taken out from the screw conveyor 13. When discharging from the bottom discharge chute 15, the discharge amount is controlled so that the layer height ΔH becomes constant.

FIG. 2 shows the structure of the main part of the fluidized bed classifier 21 according to one embodiment of the present invention. The same reference numerals are attached to the portions corresponding to the configuration shown in FIG. It should be noted that the cross-sectional area of the superficial portion where the fluidized bed is formed is reduced by the cross-sectional reduction member 22 in the vicinity of immediately above the porous dispersion plate 3. In the present embodiment, the cross-sectional reduction member 22 is hermetically sealed from the vacant tower 4 by the flange portion 23.

FIG. 3 is a sectional line III-II shown in FIG.
It is the sectional view seen from I. Further, FIG. 4 shows a cross section when the empty tower 24 has a cylindrical shape. Further, in FIG. 5, the cross-sectional reduction member 25 is inserted into the empty tower 4 by the cylinder 26,
The structure in which the insertion length is adjustable is shown. An airtight seal portion 27 hermetically seals the space between the empty tower 4 and the cross-sectional reduction member 25.

FIG. 6 shows a state in which the cross-sectional area of the superficial portion is reduced, the dead portion 28 is formed above the cross-section reducing member 22, and the cross-sectional area of the fluidized bed 29 is reduced by the configuration of FIGS. Indicates. In this state, the flow velocity ub in the portion where the cross section is reduced is higher than the superficial velocity u0, and u0 <ub (1).

FIG. 7 shows a construction in which the fluidized bed classifier 1 having the construction shown in FIG. 1 is used for treating the exhaust gas from the lime fluidized bed calcining apparatus 30. Exhaust gas is guided from the lime fluidized bed firing device 30 to the dust collector 31 to separate the dust. A small amount of coarse particles are mixed in this dust, and in order to use the dust as a valuable material, it is necessary to classify and remove the coarse particles. Therefore, the fluidized bed classifiers 1 and 21 are used. The exhaust gas from the fluidized bed classifiers 1 and 21 is guided to the dust collector 32, and fine powdery by-products are separated. Fluidized bed classifiers 1, 2
From No. 1, coarse particles are separated and returned to the raw material of the lime fluidized bed firing apparatus 30 for reuse.

FIG. 8 shows the relationship between the particle size dp of the powdery raw material and the flow rates ut and umf. umf is a flow velocity at which fluidization of particles having the classified particle diameter d1 starts, and ut indicates a terminal velocity. In order to perform classification with the classified particle size d1, it is necessary to set the terminal velocity ut to u0. When coarse particles having the maximum particle size d2 are mixed in the raw material, when the terminal velocity is u0, the particle size d2
However, since it is lower than the fluidization start speed umf, it cannot be fluidized. If unfluidized coarse particles settle and accumulate at the bottom of the fluidized bed, it is necessary to stop the operation and discharge the coarse particles for cleaning. In this case, if the fluidized bed is formed at ub, which is a superficial velocity at which coarse particles are fluidized, particles larger than the particle diameter d1 to be classified are also scattered from the fluidized bed, which lowers the classification efficiency.

FIG. 9 is a system diagram showing a schematic structure of a fluidized bed classifier according to another embodiment of the present invention. The parts corresponding to those in the above embodiment are designated by the same reference numerals. A discharge chute 14 for discharging the classified coarse powder is connected to a discharge port 40 formed on a side portion of the container 4, and is provided so as to extend vertically. The discharge chute 14 is provided with a plurality of n supply ports B ₁ , B ₂ , ..., B _n at intervals in the longitudinal direction.
The classification auxiliary gas supplied from the classification auxiliary gas supply source 41 is supplied to the supply ports B ₁ , B ₂ , ..., B _n by the flow rate adjusting valves V ₁ ,
Injected via V ₂ , ..., V _n . An airtight damper 17 is provided below the lowermost supply port B ₁ , and the container 4
The inside of the container can be hermetically sealed to allow the powder particles to be charged and discharged. The flow rate (m ³ / s) of the auxiliary gas for classification is q ₁ , q
₂ , ..., Q _n , and the inner diameter of the discharge chute is dc (m), the velocity uc (m / s) of the auxiliary gas for classification is

[0034]

[Equation 1]

[0035] The velocity uc is equal to or lower than the superficial velocity u0 of the freeboard of the container at the discharge port 40 and is higher than the fluidization start velocity umf of the coarse powder to be classified, and u0 ≧ uc> umf (3) Is adjusted to Further, just above the bottommost supply port B ₁ , the velocity of the auxiliary gas for classification uc1 (m / s)
Is

[0036]

[Equation 2]

[0037] The speed uc1 is smaller than the fluidization start speed umf of the coarse powder to be classified, and is adjusted so that uc1 <umf (5). Speed of the classification auxiliary gas flow regulating valves V _1, V _2, ..., the flow rate q _1, q ₂ of V _n, ..., is adjusted by controlling the q _n. Air is used as the auxiliary gas for classification. The other structure is the same as that of the above embodiment.

FIG. 10 is a vertical cross-sectional view showing a simplified state of the lower portion of the container in the fluidized bed forming state. The powdery or granular material fed from the raw material feeding chute 8 is fluidized by the air having the flow velocity ub passing through the porous dispersion plate 3 to form a fluidized bed 9
Is formed. The uppermost part of the fluidized bed 9 is below the discharge port 40. A large number of powder particles are discharged into the space above the bed surface of the fluidized bed 9. The large-diameter particles immediately fall and return to the fluidized bed 9, but the small-sized particles reach further upward. Further, the fine powder that has reached the terminal velocity ut at the superficial velocity u0 is discharged from the upper part together with the air. For this reason, the concentration of powder particles exponentially decreases in the height direction from the surface of the fluidized bed 9. Therefore, from the top of the fluidized bed 9 to the discharge port 40
Depending on the distance L to the discharge chute 1 from the discharge port 40
When the amount of coarse powder discharged to No. 4 changes and the distance L decreases, the amount of coarse powder discharged increases. When the classified coarse powder in the discharge chute 14 is continuously discharged to the outside by a rotary feeder as the airtight damper 17, the distance L from the top of the fluidized bed 9 to the discharge port 40 is a predetermined value. The discharge amount of the airtight damper 17 is controlled so that The distance L is, for example, 10 so that the inflow amount of the coarse powder into the discharge chute 14 and the discharge amount to the outside are balanced.
It is formed to 0 mm.

FIG. 11 is a horizontal sectional view showing the mounting positions of the raw material charging chute 8, the discharging chute 14, and the sectional reduction member 22 on the side of the container. The raw material charging chute 8 and the discharging chute 14 are located on the side of the container 4 having a circular cross section, and are connected to the container 4 on one diameter line. The axes of the raw material charging chute 8 and the discharging chute 14 are within one vertical plane, and the vertical axis of the container 4 is within this vertical plane. FIG.
As shown in FIG. 1, the cross-section reducing member 22 is the raw material charging chute 8
Although it is arranged in the direction perpendicular to the one diameter line connecting the discharge chute 14 with the discharge chute 14, the cross-sectional reduction member 22 is shown on the same side as the raw material charging chute 8 in FIG. 9 for the sake of convenience of illustration.

FIG. 12 is a system diagram showing a schematic structure of a fluidized bed classifier according to another embodiment of the present invention. The parts corresponding to those in the above embodiment are designated by the same reference numerals. Blower 5
The heater 42 is provided between the flow rate adjusting damper 6 and the flow rate adjusting damper 6. The heater 42 heats the air forming the fluidized bed. The heated air is used when the wet raw material is dried and classified. Heater 42
A fuel supply pipe 43 is connected to the fuel supply pipe 43, and a flow rate control valve 44 is provided in the middle of the fuel supply pipe 43 to control the valve opening of the flow rate control valve 44 to supply fuel to the heater 42. Is adjusted. A thermocouple 45 is arranged in the fluidized bed. The temperature control circuit 45a controls the valve opening degree of the flow control valve 44 so that the fluidized bed temperature Tb detected by the thermocouple 45 matches the set temperature of the target temperature setting circuit 45b. That is, the temperature control circuit 45a gives the control valve 44 an output for expanding the valve opening when the fluidized bed temperature Tb is low, or for closing the valve opening when the fluidized bed temperature Tb is high. An electric heater may be used as the heating source of the heater 42. When drying the wet raw material, the fluidized bed temperature T
b becomes constant at the equilibrium temperature Tc determined by the type of wet raw material, and rises again when the drying is completed. The equilibrium temperature Tc indicates a temperature range of 90 ° C or higher and 110 ° C or lower. Therefore, the target value of the fluidized bed temperature Tb is set to a temperature exceeding 110 ° C. Further, the heated air temperature T _G on the outlet side of the heater 42 is measured by a thermocouple. The heating air temperature T _G is approximately 200 ° C. or higher 3 so that the target value of the fluidized bed temperature Tb is secured.
It indicates the temperature range below 00 ° C and is used as an operation control index value. Wet raw materials include limestone, silica sand, pulverized coal, fly ash, cement raw materials, and fine aggregate for concrete, all of which can be handled.

The container 4 has a first pressure gauge 46 for detecting the pressure immediately above the dispersion plate 3 and a second pressure gauge 46 for detecting the pressure on the freeboard.
A pressure gauge 47 is provided. First pressure gauge 46 and second
The output of the pressure gauge 47 is input to the pressure difference control circuit 48.
The pressure difference control circuit 48 sets the pressure difference to the target pressure difference setting circuit 4
The air-tight damper 1 so that it matches the set pressure difference of 8a.
Control 7 That is, the pressure difference control circuit 48 outputs to the airtight damper 17 an output that opens the airtight damper 17 when the pressure difference becomes large, or an output that closes the airtight damper 17 when the pressure difference becomes small. give. When the classified coarse powder in the discharge chute 14 is intermittently discharged to the outside by the airtight damper 17, the target pressure difference between the first pressure gauge 46 and the second pressure gauge 47 is set to 300 mmAq, for example.

From the middle of the heater 42 and the flow rate adjusting damper 6, a classification auxiliary gas supply pipe 49 is branched.
The classification auxiliary gas supply pipe 49 is connected to the flow rate adjusting valve V ₁ ,
Connected to the discharge chute 14 via V ₂ , ..., V _n . The air supplied from the blower 5 is blown into the wind box 2 and the discharge chute 14 via the heater 42. The other structure is the same as that of the above embodiment.

FIG. 13 is a system diagram showing a schematic structure of a fluidized bed classifier according to another embodiment of the present invention. Blower 5
Is connected to the blower port 7 by a pipe 50 via a flow rate adjusting damper 6. The pipe 51 is branched off from the downstream side of the flow rate adjusting damper 6 and connected to the discharge chute 14 via the flow rate adjusting valve V. Further, the pipe 51 is branched from the upstream side of the flow rate adjusting valve V and connected to the auxiliary gas supply source 41 for classification. Therefore, with both the flow rate adjusting damper 6 and the flow rate adjusting valve V open, the blower 5 can supply air to the wind box 2 and the discharge chute 14. When the flow rate adjusting damper 6 is closed and the flow rate adjusting valve V is opened, the classification auxiliary gas supply source 41 can supply air to the wind box 2 and the discharge chute 14. In this way, the wind box 2 and the discharge chute 14 can be supplied with air from the supply sources of the two systems, so that they can be replenished with each other when the air amount of either of the air supply sources is insufficient. The other structure is the same as that of the above embodiment.

FIG. 14 is a diagram showing an example of classification characteristics of the fluidized bed classifier having the configuration shown in FIG. A total of 50 kg of limestone raw material from the raw material charging chute 8 for 30 minutes
Supplying air volume 7 Nm ³ / min, superficial velocity u
When classified under the condition of 0 = 1.83 m / s, 6.1 kg of scattered powder was discharged from the fine powder discharge port 10 on the upper part of the container 4, and 43.9 kg of residue remained in the container 4. FIG. 14 shows the relationship between the particle size and the passing amount of the raw material 60, the scattered powder 61, and the residue 62 in the container 4. The particle size of the scattered powder is almost 0.5 mm or less, and the particle size of the scattered powder is 0.5 mm.
Almost no powder or granules exceeding 10 were contained. The residue contained almost no fine powder having a particle size of 0.2 mm or less. Therefore, the raw materials were well classified.
Further, FIG. 14 shows the relationship between the granularity and the distribution rate 63. The particle size corresponding to a distribution rate of 50% was 0.18 mm, and the index K indicating the sharpness of classification defined by the following formula 6 was 0.81.

[0045]

(Equation 3)

Since K is 1 in the ideal classification, it was confirmed that the classification characteristics of the fluidized bed classifier were good.

In the configuration shown in FIG. 1, the flow rate of the flow rate adjusting damper 6 is controlled according to the required particle size, and the flow velocity ub is adjusted. In the embodiment shown in FIGS. 2 to 6 and 9 to 13,
Even if the fluidization speed ub is increased by reducing the cross-sectional area,
Since the superficial velocity u0 can be made small, the coarse particles can be fluidized within a range in which the superficial velocity uo does not exceed the fluidization start velocity umf of the granular material to be classified.

By using the fluidized bed, even if the fine powder in the raw material is attached to the coarse particles or the fine powder is agglomerated with each other, the fine powder is separated and scattered during the fluidization.
As a result, the fine particles are less likely to be mixed and discharged in the coarse particles, and the classification efficiency is improved.

In each of the above examples, the classification of the dust in the exhaust gas from the lime fluidized bed burning equipment is mainly shown, but it is needless to say that it can be similarly used for the classification of other powders and granules. Is. Furthermore, heat exchange or drying can be performed at the same time as the classification. For example, it is also possible to use a gas other than air, to cause a chemical reaction under high pressure or negative pressure conditions, or to promote another chemical reaction by using the granular material as a catalyst.

[0050]

As described above, according to the present invention, the particle size for classifying the particles staying in the fluidized bed formed by adjusting the gas flow rate and the particles scattered from the fluidized bed can be easily adjusted. can do. Since the fluidized bed is used for classification, the particle size can be set within the range of 100 μm to 1 mm, and the classification efficiency can be enhanced.

Further, according to the present invention, since the cross-sectional area of the superficial portion forming the fluidized bed is reduced, the flow velocity of the gas forming the fluidized bed is more than the flow velocity for transporting particles scattered from the fluidized bed. Can also be larger. Since particles having a wide range of particle diameters can be fluidized, poor fluidization is unlikely to occur, and classification efficiency is improved. Furthermore, even if the classified particle size is changed, the classification efficiency does not decrease.

Furthermore, according to the present invention, the classification auxiliary gas can be blown into the discharge chute for discharging the classified coarse powder. The speed of the auxiliary gas for classification is set so that fine powder having a particle size of classification or less does not mix into the discharge chute, and coarse powder in the discharge chute remains in the discharge chute and does not return to the inside of the container. Therefore, the classification efficiency is significantly improved.

[0053]

Furthermore, according to the present invention, when the coarse powder is continuously discharged, the discharge flow rate of the airtight discharge means is controlled so that the distance from the top of the fluidized bed to the discharge port becomes a predetermined value. It is possible. Further, when the coarse powder is discharged intermittently, the airtight discharging means can be controlled so that the difference between the gas pressure directly above the dispersion plate and the gas pressure on the freeboard becomes a predetermined value. Therefore, stable operation can be continuously performed for a long time.

Furthermore, according to the present invention, the fluidizing gas supplied from the blower can be used as the auxiliary gas for classification by changing the piping, and conversely, it is supplied from the auxiliary gas supply for classification. An auxiliary gas for classification can be used as a fluidizing gas. In this case, since the fluidizing gas and the classification auxiliary gas can be supplied from the gas supply sources of two systems, they can be replenished with each other when the gas amount of either gas supply source is insufficient. .

[Brief description of drawings]

FIG. 1 is a system diagram showing a schematic configuration that is a prerequisite of the present invention.

FIG. 2 is a vertical sectional view of a main part of a fluidized bed classifier 21 according to an embodiment of the present invention.

3 is a cross-sectional view taken along the section line III-III shown in FIG.

FIG. 4 is a cross-sectional view of the configuration basically shown in FIG. 2 when the shape of the empty column is cylindrical.

FIG. 5 is a vertical cross-sectional view of the configuration basically shown in FIG. 2 in which the reduction rate of the cross section can be changed.

FIG. 6 is a vertical cross-sectional view showing the operation of the configuration shown in FIGS.

7 is a systematic diagram of an apparatus using the configuration shown in FIG.

FIG. 8 is a graph showing the operating principle of the present invention.

FIG. 9 is a system diagram showing a schematic configuration of a fluidized bed classifier according to another embodiment of the present invention.

FIG. 10 is a vertical sectional view showing a simplified state of the lower portion of the container in a fluidized bed forming state.

FIG. 11 is a horizontal cross-sectional view showing the mounting positions of the raw material charging chute, the discharge chute, and the cross-sectional reduction member on the side of the container.

FIG. 12 is a system diagram showing a schematic configuration of a fluidized bed classifier according to another embodiment of the present invention.

FIG. 13 is a system diagram showing a schematic configuration of a fluidized bed classifier according to still another embodiment of the present invention.

FIG. 14 is a diagram showing an example of classification characteristics of the fluidized bed classifier having the configuration shown in FIG. 1.

[Explanation of symbols]

 1,21 Fluidized bed classifier 2 Air box 3 Porous dispersion plate 4,24 Empty tower 5 Blower 6 Flow rate adjustment damper 9,29 Fluidized bed 11 Cyclone 12 Bag filter 14 Discharge chute 15 Bottom discharge chute 16,17,18 Airtight damper 22, 25 Cross-section reduction member 26 Cylinder 27 Airtight seal part 30 Lime fluidized bed firing device 40 Exhaust port 41 Auxiliary gas supply source for classification 45 Thermocouple 46 First pressure gauge 47 Second pressure gauge V1, V2, ..., Vn Flow rate adjustment Valves B1, B2, ..., Bn supply ports

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Murao 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries Ltd. Kobe factory (72) Noboru Ichiya Higashi-kawasaki-cho, Chuo-ku, Kobe-shi, Hyogo 3-1-1 No. 1 Kawasaki Heavy Industries Ltd. Kobe factory (56) Reference JP 62-289231 (JP, A) JP-B 2-26536 (JP, B2) JP-B 53-8665 (JP, B2) ) "Fluidization Law", written by Daizo Kunii (Nikkan Kogyo Shimbun, issued October 25, 1937), Figure 2.10 on page 26.

Claims (4)

(57) [Claims] 1. A container, a raw material charging means for charging a granular raw material into the container, and a fluidized bed forming means for blowing a gas from below the dispersion plate into the raw material charged into the container to form a fluidized bed. A flow rate adjusting means for adjusting the flow velocity of the gas forming the fluidized bed, and a cross section which is provided immediately above the dispersion plate in the container in which the fluidized bed is formed and which can adjust the cross-sectional area of the superficial part. A fluidized bed classifier, comprising: a reduction member, a particle separating means for separating particles staying in the formed fluidized bed, and particles scattered from the fluidized bed. 2. A coarse powder, which is connected to an outlet formed on a side portion of the container and extends vertically, is discharged from a lower portion and is classified between the outlet and the airtight discharging means. A discharge chute having a plurality of supply ports formed at intervals in the longitudinal direction, an airtight discharge means provided at the bottom of the discharge chute, and an auxiliary gas for classification are formed at intervals in the longitudinal direction of the discharge chute. And an auxiliary gas supply source for classification respectively supplied from each of the plurality of supply ports, wherein the speed of the auxiliary gas for classification is selected at the discharge port to be equal to or lower than the superficial velocity u0 of the freeboard of the container. The fluidized bed classifier according to claim 1. 3. The fluidized bed classifier according to claim 2, wherein the velocity of the auxiliary gas for classification is selected at a value exceeding the fluidization start rate umf of the coarse powder to be classified at the outlet. . 4. The speed of the auxiliary gas for classification in the discharge chute just above the lowermost supply port is selected to be less than the fluidization start speed umf of the coarse powder to be classified. Fluidized bed classifier.