JPS6252616B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sonic fluidized bed classification device incorporating a sonic generator. The sonic fluidized bed apparatus according to the present invention can be used for classification, heating, cooling, drying, adsorption, desorption, etc. of fine particles, and solid-gas reactions.

Conventionally, regarding the formation of a general fluidized bed of particles,
A conventional fluidized bed or a horizontal fluidized bed apparatus having a net-like or lattice-like packing is known, and the problem of adhesion and aggregation between particles has not occurred. However, when the particles become fine, the adhesion and aggregation between the particles becomes strong, making it difficult to fluidize, and even when various fillers are used, it has not been possible to prevent adhesion and aggregation.
Therefore, great efforts have been made to prevent the conventional adhesion and aggregation of fine particles, to allow each fine particle to perform its function, and to extract individual fine particles.

For example, when classifying fine particles, a so-called dry classification method using a fluidized bed device with a packing as described above causes severe adhesion and agglomeration of fine particles, making classification impossible, so a wet classification method is generally adopted. Wet classification methods include the water sieve method known as the so-called Hamilton classification method, and the ultrasonic wet classification method in which fine particles are classified while suspended in a solvent under ultrasonic vibration using a metal microfilter. but,
The former method is inefficient and has poor classification accuracy, while the latter method has good classification accuracy, but has the drawbacks of expensive metal microfilters and poor classification efficiency. Therefore, it has been difficult to classify a large amount of fine particles inexpensively and quickly using any of the methods.

The present invention solves these problems and relates to a sonic fluidized bed device that can be used for classification where fine particles are frequently or continuously required to be supplied and withdrawn.

That is, the present invention includes a breathable dispersion plate in the lower part of the container, a gas inlet below the dispersion plate, a gas outlet in the upper part of the container, and a sound wave generator capable of generating sound waves of 5 to 800 Hz. The present invention relates to a sonic fluidized bed classification device suitable for classifying fine particles. A feature of the present invention is that a fluidized bed is formed by gas from below by preventing agglomeration of fine particles using sound waves.

The sonic fluidized bed device according to the present invention includes a suitable gas blower, a powder supply device connected to an inlet for supplying fine particles from the side surface of the fluidized bed region of a cylindrical container, and an inlet for taking out fine particles. connect,
A device for accumulating fine particles;
Accumulation equipment, etc. will be installed as necessary. As these devices, devices known to those skilled in the art may be used.

In the sonic fluidized bed device according to the present invention, the container may have any shape as long as it allows airflow to pass from below to above, and has micropores at the bottom that support fine particles and allow gas to pass through. It has a dispersion plate with a gap. As the dispersion plate, filter paper, glass filter, etc. can be used.

The inlet and outlet for fine particles may be installed on the side surface of the container depending on the purpose, and if necessary, it is also possible to form a continuous sonic fluidized bed device in which the containers described above are arranged in series.

The sound waves that prevent the particles being fluidized by the gas from agglomerating and form a complete fluidized bed are generated by a known method and transmitted to the particles, for example, by a sonic generator attached to the bottom of the container. A sound wave generator is a speaker, etc. There are no particular restrictions on the method of generating sound waves and the method of transmitting sound waves to fine particles, as long as they are effective for the fluidized bed form of fine particles.
A net-like or grid-like packing can also be used in the upper part of the fluidized bed, if desired.

Sound waves with a frequency of 5 to 800 Hz are effective, and agglomeration of fine particles cannot be prevented at frequencies outside this range. The output of the sound wave may be determined depending on the properties and amount of the particles.

The fine particles may be of any kind, such as resin particles, pigments, toners, general inorganic particles, glass particles, metal particles, carbon particles, solid catalyst particles, etc.
It may also be porous. It may be one with a particle size distribution or one with a difference in specific gravity. The target particle size is suitably 100μm or less, preferably 0.5~
Particles of 80 μm are preferable.

When operating the sonic fluidized bed classification apparatus according to the present invention, the gas velocity is determined by the size of the classification boundary of the powder or granular material to be classified, and when classification is not performed, the gas velocity is kept within a range in which the smallest particles are not scattered. The feeding rate of the powder, the heights of the inlet and outlet, and the size of the container are appropriately determined depending on the required classification accuracy.

The present invention will be explained using an example in which it is used for classifying fly ash. FIG. 1 shows a batch type sonic fluidized bed classification apparatus. Reference numeral 1 denotes a blower, and this blower supplies gas through an inlet 2 to a container 4 through a dispersion plate 3, and fluidizes fine particles 6 supplied through a particle supply port 5. In this case, the container is filled with a filler 7 made of a cylindrical wire mesh. The filling is generally 2 to 5 meshes,
It is best to use one with an inner diameter of 1.5 to 10 cm. On the other hand, oscillator 8
The sound waves generated are amplified by an amplifier 9, and a speaker 10 generates sound waves within the device. The classified particles are collected by a collector 12 through a discharge port 11 and stored in a storage tank 13.

Next, the operation of the apparatus shown in FIG. 1 will be further explained. The gas forced by the blower 1 is blown out through the dispersion plate 3 into the interior containing the filler 7, and fluidizes the fine particles already supplied. At that time, the sound waves generated by the oscillator 8 are transmitted to the amplifier 9.
Since the amplified signal is amplified by the speaker 10 and transmitted into the device by the speaker 10, this action loosens the adhesion and agglomeration of the particles, and smoothes the fluidization of the particles.
In such a state, the mixed fine particles can be classified under a constant gas flow rate, and relatively fine particles can be collected in the particle collector 12 at the top of the device. That is, this process is continued at a constant gas flow rate until no more particles flow into the particle collector 12. If particles no longer flow out, the gas flow rate can be gradually changed from a low speed to a high speed and the same operation can be repeated to remove the gas from the collector 12.
Particles are classified by collecting particles from smaller to larger particles within the container.

FIG. 2 shows another embodiment of the present invention. By using a plurality of devices according to the present invention and cascading them, a large number of fine particle groups can be classified continuously. That is, the gas that has passed from the blower 14 through the gas inlets 15, 16, and 17,
container 21 through distribution plates 18, 19 and 20;
22 and 23, and the fine particles supplied from the hopper 24 are continuously classified into four sizes, and the coarse particles are sent to the collectors 25, 26, and 2, respectively.
7 and 28 and can be collected in storage tanks 29, 30, 31 and 32. The collectors 33 and 34 serve as hoppers for supplying particles to the next container. In order to improve the dispersion of particles within the device, speakers 35, 36 and 37 are connected to sound wave generators 41, 37 via amplifiers 38, 39 and 40.
42 and 43 to generate sound waves.

Application Example 1 This application example is an example in which the apparatus shown in FIG. 1 is used for classification. In other words, the relationship between the gas flow rate and partial classification efficiency is calculated when the flyash is classified by filling a cylindrical wire mesh ring with an inner diameter of 1.4 cm and 5 meshes, using filter paper as a dispersion plate, and fluidizing it while oscillating an 80 Hz sound wave. This is what is shown. However, the diameter of the fluidized bed device is 150 mm, and the height from the distribution plate is 300 mm.
mm, and the height of the fluidized bed was 150 mm. The container was made of acrylic resin plastic. The fly ash has a particle size distribution shown in Figure 3.
g was supplied. The outer diameter of the speaker is 150mm,
It was attached to the bottom of the distribution plate as shown in Figure 1. The output of the 80Hz sound wave was 200 Watts. The results are shown in FIGS. 4 and 5.

Figure 4 shows the particle size distribution of classified particles and the gas flow rate U.
(cm/sec). Curves 44, 45, 46, 47 and 48 in Fig. 4 have gas flow velocities of 0.2 cm/sec, 0.84 cm/sec, and 1.88 cm/sec, respectively.
sec, 3.3cm/sec and 7.5cm/sec.

In Fig. 5, the horizontal axis is the gas flow velocity U (cm/sec),
The vertical axis is the partial classification efficiency βi (the particles coming out from the top are sieved, the weight of particles of the corresponding diameter is measured, and the weight is converted per unit time, divided by the amount of particles of the corresponding diameter supplied per unit time). (value). Fifth
In the figure, curves 49, 50, 51, 52 and 53
The particle size is 0 to 5 μm, more than 5 μm and less than 10 μm, more than 10 μm and less than 15 μm, and more than 15 μm and less than 20 μm.
The changes in βi are shown for those less than m and more than 20 μm and less than 30 μm.

In FIGS. 4 and 5, the closer the curves are to the vertical, the better the classification performance is because the residual inside the column and the upper part can be separated with a slight difference in wind speed. The superiority of the sonic fluidized bed device according to the present invention can be understood from FIGS. 4 and 5.

Comparative Example 1 The fly ash shown in Application Example 1 was classified using a so-called vibrating fluidized bed classifier, in which the speaker in the equipment shown in Figure 1 was removed and a vibration device was installed to mechanically vibrate the fluidized bed device instead. I did this. The results are shown in Figure 6. FIG. 6 shows the relationship between the particle size distribution of classified particles and the gas flow rate in the same way as FIG. 4. In FIG. 6, curves 54 and 55 indicate gas flow rates of 3.0 cm/sec and 18 cm/sec.
Shows the results when sec. However, the vibration device
The vibration frequency was approximately 2 Hz and the amplitude was 0 to 3 mm.

Comparative Example 2 Application Example 1 was carried out in accordance with Application Example 1, except that the sound waves were not oscillated. However, when the gas flow rate was varied variously, it was found that when the gas flow rate was 4 cm/s or less, the particle layer was hardly fluidized due to the agglomeration of particles, and therefore, when the gas flow rate was 4 cm/s or less, the particles could not be classified. I couldn't do it. Gas flow rate 5.5
The results of the particle size distribution of the classified particles at cm/s and 7.5 cm/s are shown in FIG. 7 as a relationship between cumulative weight (%) and particle diameter (μm). In FIG. 7, curve 56 shows the results when the gas flow rate is 5.5 cm/s, and curve 57 shows the results when the gas flow rate is 7.5 cm/s. Further, FIG. 8 shows the relationship between the partial classification efficiency βi and the gas flow rate obtained from these results. Curve 5 in Figure 8
8, 59, 60, 61 and 62 have particle diameters of 0 to 5 μm, more than 5 μm and 10 μm or less, and 10 μm, respectively.
The changes in βi are shown for those larger than 15 μm or less, more than 15 μm but not more than 20 μm, and more than 20 μm and not more than 30 μm. From these results, it can be seen that the classification efficiency is significantly inferior in the absence of sound wave oscillation.

Application example 2 In application example 1, 10~
Using particles with a diameter of 15 μm, the frequency of the sound wave was set to 5.
Hz, 10Hz, 30Hz, 80Hz, 200Hz, 500Hz and 800Hz
The process was otherwise carried out in accordance with Application Example 1.
These results are shown in FIG. 9 as a relationship between partial classification efficiency βi and gas flow rate (cm/s). In Figure 9,
The plot shown by ▲ is the one at 5Hz, the plot shown by × is the one at 10Hz, the plot shown by △ is the plot at 30Hz, and the plot shown by □ is the one at 30Hz.
The plot at 80Hz, the plot indicated by ○ is 200
Plot at Hz, plot indicated by ● is 500Hz
The plot when and the plot shown by is 800
This is the plot at Hz.

As is clear from these results, it can be seen that the effect of the present invention is achieved when the frequency of the sound wave is 5 to 800 Hz.

As is clear from the application examples and comparative examples, it can be seen that by using the sonic fluidized bed classification apparatus according to the present invention, adhesion and aggregation of fine particles can be eliminated and efficient classification of fine particles can be achieved. By changing the gas flow rate, it is possible to classify fine particles of the required particle size, and this method has great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the sonic fluidized bed classifier according to the present invention, and FIG. 2 is a schematic diagram showing another example of the sonic fluidized bed classifier according to the present invention. Third
Figure 4 is a graph showing the particle size distribution of the fly ash used in Application Example 1, Figure 4 is a graph showing the classification results in Application Example 1 in terms of particle size distribution at a certain gas flow rate, and Figure 5 is a graph showing the particle size distribution of the fly ash used in Application Example 1. It is shown by the relationship between classification efficiency and gas flow rate. FIG. 6 is a graph showing the results of Comparative Example 1 in terms of particle size distribution at a certain gas flow rate. FIG. 7 is a graph showing the classification results in Comparative Example 2 in terms of particle size distribution at a certain gas flow rate;
FIG. 8 similarly shows the relationship between partial classification efficiency and gas flow rate. FIG. 9 is a diagram showing the classification effect in Application Example 2 by plotting the relationship between partial classification efficiency and gas flow rate at a certain gas flow rate. Explanation of symbols, 1...Blower, 2...Gas inlet, 3...Dispersion plate, 4...Container, 5...Particle supply port, 6...Fine particles, 7...Filling material, 8...Oscillator , 9...amplifier, 10...speaker, 11...
...Discharge port, 12...Collector, 13...Storage tank, 14
...Blower, 15,16,17...Gas inlet,
18, 19, 20... Dispersion plate, 21, 22, 23
... Container, 24 ... Hopper, 25, 26, 2
7, 28... Collector, 29, 30, 31, 32...
... Storage tank, 33, 34 ... Collector and hopper, 3
5, 36, 37...speaker, 38, 39, 4
0...Amplifier, 41, 42, 43...Sonic wave oscillator.

Claims (1)

[Claims] 1 Classifies fine particles by equipping a container with an air-permeable dispersion plate at the bottom, a gas inlet below the dispersion plate, a gas outlet at the top of the vessel, and a sonic generator capable of generating sound waves of 5 to 800Hz. Sonic fluidized bed classification equipment suitable for