JP3427178B2 - Method and apparatus for fluidizing granular material layer in closed container - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for fluidizing a granular material layer composed of various granular materials and the like in a closed container to form a fluidized bed.

[0002]

2. Description of the Related Art A fluidized bed formed by introducing an air stream into a granular material layer made of various powders and particles to fluidize it is used as a fuel for drying raw materials and power generation in the chemical industry. It is widely used for combustion, various reactions using catalysts, granulation and coating.

In the above-mentioned fields, particularly when forming a fluidized bed in the step of performing heat treatment for drying or the like, it is necessary to fluidize the powder or granules forming the fluidized bed in a closed system. , There is no dissipation of powder or granules that make up the fluidized bed or raw materials that are subjected to heat treatment, etc., and atmosphere adjustment is easy,
It is possible to quickly obtain a more uniform heating field.

By the way, in recent years, the treatment of dioxins generated during refuse incineration has become a big problem. It is known that the dioxin contained in the combustion ash during refuse incineration is thermally decomposed in an oxygen-free atmosphere at a temperature of 400 ° C. Therefore, in order to treat dioxin in the combustion ash, it is desirable to perform it in a closed system from the viewpoint of improving treatment efficiency and safety.

[0005]

The present invention has been made in view of the above problems, and an object thereof is to propose a method for efficiently forming a fluidized bed in a closed container.

[0006]

A method for fluidizing a granular material layer in a closed container according to the present invention comprises a gas introducing means for introducing a gas into the granular material layer and a valve in the closed container. Then, the gas introducing means and a communication means for communicating between the ceiling portion inside the closed container or the vicinity thereof, and a vibration means for vibrating the closed container are provided, and a valve is provided in the communication means, The airtight container is vibrated in the vertical direction by the vibrating means, and the flow of gas in the airtight container caused by this vibration is controlled by opening and closing the valve provided in the communicating means, while passing through the gas introducing means. The powder or granular material layer is fluidized by being introduced into the powder or granular material layer.

In the method according to the present invention, the fluidization of the powder and granules is caused in the closed container by vibrating the container and the inertial motion of the powder and granules to generate a flow in the gas in the closed container, and the flow thereof. Is controlled appropriately. Therefore, since a fluidized bed can be formed without introducing gas from the outside, when performing heat treatment using the fluidized bed, there is no dissipation of the powder or granular material forming the fluidized bed or the raw material to be subjected to the heat treatment, etc.
The atmosphere can be easily adjusted and a uniform heating field can be obtained. Further, since the treatment is performed in a closed system, it is particularly suitable for heat treatment in an oxygen-free atmosphere and decomposition treatment of harmful substances such as dioxin contained in combustion ash of refuse.

A method of fluidizing a powdery or granular material layer in a closed container according to the present invention is characterized in that opening / closing of the valve is controlled in synchronization with vibration of the vibrator. Thereby, it becomes possible to more appropriately control the vibration of the container and the flow of gas generated by the inertial motion of the powder and granules.

The present invention also relates to a device for fluidizing a granular material layer to form a fluidized bed.

That is, the fluidizing apparatus for the granular material layer according to the present invention is arranged so that a space having a predetermined size is provided between the ceiling part and the bottom part inside the closed container. A dispersion plate, a space between the ceiling portion and the dispersion plate, so as to connect the space between the bottom portion and the dispersion plate, a ventilation pipe provided in the closed container, the A valve provided in the middle of the ventilation pipe, and a vibrating machine for vibrating the hermetically sealed container, forming a powdery particle layer on the dispersion plate, and vertically moving the hermetically sealed container by the vibrating machine. It is characterized in that the powdery or granular material layer is fluidized by vibrating and controlling the flow of the gas in the closed container caused by the vibration by opening and closing the valve of the ventilation pipe.

Further, the fluidizing device for the granular material layer according to the present invention is provided between the closed container and the vicinity of the ceiling and the bottom inside the closed container, and opens toward the ceiling and the bottom, respectively. A ventilation pipe thereby connecting the ceiling and the bottom portion, a valve provided in the middle of the ventilation pipe,
And a vibrating device for vibrating the closed container, and a powder layer is formed so as to bury the lower end of the ventilation pipe.

In the fluidized bed apparatus of the present invention, the fluidized bed is formed in a closed vessel by vibrating the vessel and the resulting inertial movement of the granular material to cause a gas flow in the closed vessel. And by controlling the flow appropriately. Therefore, since a fluidized bed can be formed without introducing gas from the outside, there is no loss of powder or granular materials that make up the fluidized bed or raw materials to be subjected to heat treatment, etc., atmosphere adjustment is easy, and a uniform heating field is provided. Processing can be performed. Further, since the treatment is carried out in a closed system, the present invention is particularly suitable for heat treatment in an oxygen-free atmosphere and decomposition treatment of harmful substances such as dioxin contained in combustion ash of refuse.

Further, the fluidizing apparatus for the granular material layer according to the present invention is characterized in that the opening / closing of the valve is controlled in synchronization with the vibration of the vibrator. This causes vibration of the container,
This makes it possible to more appropriately control the flow of gas generated by the inertial motion of the granular material.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a fluidizing device for a granular material layer according to the present invention. The device 10 includes a closed container 11
And a vibrator 12 attached to the lower part of the closed container 11 and a ventilation pipe 13. The airtight dispersion plate 14 is provided in the closed container 11, and the powder layer 15 is formed on the dispersion plate 14. Further, a granular material stopper 16 for suppressing an excessive rise of the granular material is provided between the granular material layer 15 and the ceiling portion of the closed container 11. The ventilation pipe 13 is provided so as to connect an upper space 17 and a lower space 18 of the dispersion plate provided in the closed container 11 to each other, and a valve 19 is provided in the middle. The upper space is divided by the granular material stopper 16 into a granular material moving portion 17a and a gas storage portion 17b. The valve 19 is composed of a steel ball 20, a pedestal 21 and a stopper 22, and when the steel ball 20 is seated on the pedestal 21, the flow of gas in the ventilation pipe 13 is blocked. Also, the stopper
22 controls the upward movement of the steel ball 20. The vibrator 12 is of a type that mechanically generates vibration using a crank mechanism or the like in order to obtain a sufficient amplitude for forming a fluidized bed.

FIG. 2 shows the container 11 and the granular material layer 15 when the granular material is introduced into the closed container 11 of the apparatus 10 shown in FIG. 1 and the container 11 is vibrated to perform a fluidized bed formation experiment. FIG. 4 shows the displacement of the steel ball 20, the vibration acceleration of the container, and the time change of the gas pressure in the container 11, respectively. Here, the specifications of the experimental apparatus are as shown in Table 1 below, and the conditions when the experiment was performed are as shown in Table 2 below.

[0017]

[Table 1]

[0018]

[Table 2]

In FIG. 2 (b), the gas in the container is
The pressure is the pressure P in the space 18 below the dispersion plate 15._LAnd the upper
Pressure P in space (gas reservoir) 17b_UDifferential pressure with ΔP = P_L
-P _UIt shows with.

FIG. 2A shows a container 11, a powder / grain layer 15, a steel ball 20.
And the vibration acceleration of the container with time. In the figure, the bottom dead center of the container 11, that is, the position when the container 11 is stationary before vibration is set to 0.

As shown in FIG. 2A, when the container 11 is vibrated vertically from the position of the bottom dead center O, the container 11 first rises at the maximum acceleration. Here, the acceleration is positive in the direction opposite to the direction in which gravity acts, that is, in the upward direction.
The acceleration decreases as the container 11 rises, and when it reaches the point A1 in the figure, the acceleration of the container 11 becomes smaller than the gravitational acceleration −g, whereby the powder layer 15 and the steel balls 20 move with respect to the container 11. To surface. As a result, the gas (air) in the space 17 on the upper side of the dispersion plate 15 is pushed by the granular material layer and flows into the space 18 on the lower side through the ventilation pipe 13. 2 (b), that is, looking at the pressure difference ΔP between the pressure P _L of the lower space 18 of the dispersion plate 15 and the pressure P _U of the upper space (gas reservoir) 17b, the container 1
The differential pressure ΔP is 0 from the bottom dead center O to A1 of 1, but A1
Therefore, the differential pressure ΔP is negative. This is nothing but an indication that the above-described gas movement is occurring.

Next, when the container 11 is further raised, as shown in FIG.
At point B1 in (a), the steel ball 20 reaches a height of 5 mm, that is, the maximum height regulated by the stopper 22. After that, the container 11 starts to descend, and the steel ball 20 makes a free fall motion after coming into contact with the stopper 22, but since the acceleration of the container 11 is smaller than the gravitational acceleration −g, the container 22 remains in contact with the stopper 22. Exercise with. After that, after the C1 point, the container 11
Since the acceleration of is greater than the gravitational acceleration -g,
20 descends with respect to container 11. On the other hand, the granular material layer 15 is B
Even after 1 point, it will continue to rise due to inertia. for that reason,
Ventilation pipe from space 17 above dispersion plate 15 to space 18 below
Gas movement through 13 also continues. Then the powder layer 15
From the C1 point to the D1 point, which will be described later, the container 11 starts descending.

When the container 11 descends to reach point D1, a steel ball
20 sits on the pedestal 21 and closes the ventilation pipe 13. In addition, the granular layer 15
Is descending with respect to the container 11, the air in the lower space 18 is compressed. Therefore, the differential pressure ΔP sharply increases as shown in FIG. 2 (b) and reaches a peak at point E.

After that, the air in the lower space 18 is dispersed by the dispersion plate 14
And passes through the granular material layer 15 and moves to the upper space 17. As a result, the differential pressure ΔP is reduced and the granular material layer 15
Is fluidized and a fluidized bed is formed. In FIG. 2 (b), the fluctuation of the pressure difference ΔP between points E and A2 is due to the balance between the lowering of the granular material layer and the passage of air through the granular material layer. Is.

Further, the container 11 turns from descending to ascending
When the two points are reached, the acceleration of the container 11 is again gravitational acceleration-g.
Since it is smaller than the above, the granular material layer 15 and the steel balls 20 float again with respect to the container. As a result, the air in the upper space 17 is pushed by the granular material layer 15 and passes through the ventilation pipe 13 and the lower space.
Move to 18. In Fig. 2 (b), the differential pressure Δ from point A2
This is why P decreases sharply to a negative value.
A fluidized bed is formed by repeating the above process.

The above process will be described in more detail below. FIG. 3 shows a state inside the container 11 in the process of A1 to B1 to C1 of FIG. At this time, since the acceleration a of the container 11 is smaller than the gravitational acceleration −g (see FIG. 2 (a)), the granular material layer 15 rises from the dispersion plate 14,
The steel ball 20 also rises from the pedestal 21. Therefore the upper space
The air inside 17 is pushed and flows into the lower space 18 through the ventilation pipe 13. It should be noted that the powder / particle stopper 16 is omitted in this figure.

Next, FIG. 4 shows a state inside the container 11 when the container 11 reaches the point D1. At this time, the acceleration a of the container 11 is larger than the gravitational acceleration −g, the granular material layer 15 descends with respect to the container 11, and the steel ball 20 also descends and sits on the pedestal 21. Therefore, the flow of air in the ventilation pipe 13 is blocked, and the air in the lower space 18 is a granular material layer.
It will be compressed by 15. Therefore, FIG.
As shown in (b), the differential pressure .DELTA.P rapidly rises.

Further, FIG. 5 shows the internal state of the container 11 from the point D1 to the bottom dead center, and then to the ascend to A2. At this time as well, the acceleration a of the container is still larger than the gravitational acceleration −g, so the powder layer 15 continues to descend, but the air in the lower space 18 causes the dispersion plate 14 and the powder layer 15 to move. It will pass and flow into the upper space 17. As a result, the air passing through the inside of the granular material layer 15 generates a large number of bubbles 23 inside the granular material layer 15 and fluidizes them. As a result, a fluidized bed is formed.

FIG. 6 shows the state of the granular material layer inside the container in the fluidized bed forming experiment conducted using the apparatus shown in FIG. Here, in FIG. 6 (a), the container has a vibration frequency of 2.8.
FIG. 6 (b) shows the case of vibrating at Hz, and the case of vibrating at a frequency of 3.1 Hz.

As shown in FIG. 6 (a), when vibrating at a frequency of 2.8 Hz, a plurality of bubbles 33 are generated in the granular material layer 32 in the container 31, and the surface of the granular material layer 32 is generated. Hasn't had any big ripples. That is, it is understood that a good fluidized bed is formed. On the other hand, as shown in Fig. 6 (b), the frequency
It can be seen that when vibrating at 3.1 Hz, large waviness occurs on the surface of the powder / granular material layer 42 in the container 41.

FIG. 7 shows changes in the differential pressure ΔP during one cycle of vibration of the container with respect to different heights of the granular material layer in the apparatus 10 shown in FIG. In the figure, the average particle size 58
This is the result of an experiment in which the height h of the granular layer using glass beads of μm was changed from 37 mm to 105 mm, the container frequency was 2.63 Hz, and the vibration amplitude was 100 mm. Note that FIG.
In the experiment showing the results in Fig. 6 (a)
A good fluidized bed is formed as shown in FIG.

As shown in FIG. 7, a rapid increase in the differential pressure ΔP is seen from around time t = 0.13 sec regardless of the height of the granular layer. From this, in this device 10, time t = 0.
The steel ball 20 of the valve 19 is seated on the pedestal in 13 seconds, that is, FIG.
It is understood that the state shown in is obtained. Next, the differential pressure ΔP reaches a peak and then sharply decreases. At this time, however, it was confirmed that air bubbles were generated in the granular material layer and a fluidized bed as shown in FIG. 6 (a) was formed. There is. That is, the differential pressure Δ
During the sharp decrease of P from the peak, air flowed in the granular layer, thereby forming a fluidized bed (see FIG. 5).
This indicates that the differential pressure ΔP is decreasing. After that, at t = 0.35 sec, the differential pressure ΔP sharply decreases again, but this is because the upward acceleration of the container becomes smaller than the gravitational acceleration −g again as shown in FIG. 3, whereby the steel ball 20 is pedestal. It shows that it will surface again away from 22.

Here, comparing FIG. 7 and FIG. 2, FIG.
It can be seen that has a tendency similar to the change in the differential pressure ΔP shown in FIG. From this, it is understood that in the present device 10, a fluidized bed is formed regardless of the height of the granular material layer, and the change in the differential pressure ΔP depends on the frequency of the container 10 and the valve 19. When the vent pipe 13 is not provided with the valve 19, the fluidized bed is not formed.

FIG. 8 shows the peak of the differential pressure ΔP with respect to the frequency of the container for the granular material layers having different heights (see FIG. 2 (b)).
Point E) of FIG. As shown in the figure, a peak of the differential pressure ΔP occurs at a frequency exceeding 2.2 Hz regardless of the height of the granular layer. This indicates that in the present device 10, the steel ball 20 of the valve 19 is the lowest frequency that moves away from the pedestal 21 and levitates and reaches the stopper 22. The differential pressure ΔP is
It has been confirmed that the increasing tendency of the peak value with respect to the frequency becomes gentle around 2,4 Hz, and at the same time, a fluidized bed as shown in FIG. 6 (a) is formed. However, after 3.0 Hz, the peak value of the differential pressure ΔP tends to decrease when the height of the granular material layer is 105 mm and 88 mm. This is because the surface of the granular material layer as shown in FIG. 6 (b) was wavy, and the air flowed through the portion where the height of the layer was relatively lowered.

From this, the change in the differential pressure ΔP is
It can be seen that it depends on the frequency of 10 and the valve 19. Therefore, in the present invention, the type of the granular material or the granular material layer depends on the frequency when vibrating the closed container for introducing the granular material for forming the fluidized bed and the characteristics of the valve provided in the ventilation pipe. It will be understood that it is possible to find the conditions for optimum fluidized bed formation depending on the height of the bed.

FIG. 9 shows another example of the fluidizing apparatus for the granular material layer according to the present invention. The device 50 includes a closed container 51.
And a vibrator 52 attached to the lower part of the closed container 51, and a ventilation pipe 53. In the illustrated apparatus 50, a plurality of ventilation pipes 53 (three of which are shown in the figure) are provided in the closed container 51, and each of these ventilation pipes is opened toward the ceiling and the bottom of the closed container 51. In addition, a valve 54 is provided for each. The valve 54 consists of a steel ball 55, a pedestal 56 and a stopper 57, as in the case of the device of FIG. The airtight container 51 is not provided with a dispersion plate like the device 10 of FIG. 1, but the powder / granular material layer 58 is formed by being spread over the bottom of the airtight container 51. A granular material stopper 59 is provided between the granular material layer 58 and the ceiling of the closed container 51, and the ventilation pipe 53
The upper end 53a of the is projected above the granular material stopper 59. Further, the granular material layer 58 is formed so as to bury the lower end 53b of the ventilation pipe 53.

As described above, the device 50 in FIG. 9 is not provided with the dispersion plate as in the device 10 in FIG. 1, but instead, the ventilation pipe 53 also serves as the dispersion plate. That is, when the vibrator 52 vibrates the closed container 51, whereby the steel ball 55 of the valve 54 in the ventilation pipe 53 separates from the pedestal 56 as shown in FIG. And flows out from the lower end 53b of the ventilation pipe 53, that is, flows to the lower side of the raised granular material layer 58.

As described above, according to the present invention, since the fluidized bed can be formed in the closed container, the granular material constituting the fluidized bed or the raw material for the heat treatment using the fluidized bed, etc. There is no heat dissipation, the atmosphere can be easily adjusted, and the treatment can be performed in a uniform heating field. Further, since the treatment is performed in a closed system, it is particularly suitable for heat treatment in an oxygen-free atmosphere and decomposition treatment of harmful substances such as dioxin contained in combustion ash of refuse.

The present invention is not limited to the above-mentioned embodiment, but various forms are possible. For example,
In the example shown in FIGS. 1 and 9, a valve made of a steel ball, a pedestal and a stopper is used as the valve, but various other types of valves can be used in the device according to the present invention. By using an electromagnetic valve or the like and synchronizing the vibration with the vibration of the closed container and performing appropriate control, a more efficient fluidized bed can be formed. Further, the ventilation pipe may be provided outside the closed container as shown in FIG. 1 or may be provided inside the closed container as shown in FIG. Further, it is also possible not to provide a powder or granular material stopper.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing changes over time in the displacement of the container, the granular material layer, the steel balls, the vibration acceleration of the container, and the gas pressure in the container when the fluidized bed is formed by the apparatus of FIG.

FIG. 3 is a diagram schematically showing movements of a powder / particle layer and steel balls in the container of FIG.

FIG. 4 is a diagram schematically showing movements of a powder / grain layer and steel balls in the container of FIG.

5 is a diagram schematically showing movements of a powder / particle layer and steel balls in the container of FIG. 1. FIG.

FIG. 6 is a photograph showing the movement of the powder / particle layer in the container of FIG. 1.

FIG. 7 is a graph showing a time change of a pressure difference in a container in powder and granular material layers having different heights.

FIG. 8 is a graph showing changes in the differential pressure with respect to the vibration frequency of the container in the granular material layers having different heights.

FIG. 9 is a sectional view schematically showing another example of the device according to the present invention.

[Explanation of symbols]

10, 50 Fluidized bed forming equipment 11,51 closed container 12,52 exciter 13,53 Vent pipe 14 Dispersion plate 15,58 Powder layer 16,59 Powder stopper 17 Space above the dispersion plate 18 Space below the dispersion plate 19, 54 valves 20,55 steel balls 21,56 pedestal 22,57 stopper

Continuation of the front page (56) Reference JP-A-11-104436 (JP, A) JP-A-1-245847 (JP, A) JP-A-62-125821 (JP, A) JP-A-50-75980 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01J 8/00 B06B 1/00 B09B 3/00

Claims (6)

(57) [Claims] 1. When fluidizing a powdery or granular material layer formed in a closed container, the closed container has a gas introducing means for introducing a gas into the powdery or granular material layer, and a valve, Communication means for communicating between the gas introducing means and the ceiling part inside the closed container or its vicinity, and a vibrating means for vibrating the closed container are provided, and the closed container is vertically vibrated by the vibrating means. And, and by introducing the gas flow in the closed container through the gas introducing means while controlling the flow of gas in the closed container caused by this vibration by opening and closing the valve provided in the communicating means, A method for fluidizing a granular material layer in a closed container, characterized by fluidizing the granular material layer. 2. The method according to claim 1, wherein the opening and closing of the valve is controlled in synchronization with the vibration of the vibration exciter to fluidize the granular material layer in the closed container. 3. An airtight container, a dispersion plate disposed inside the airtight container so that a space of a predetermined size is provided between a ceiling portion and a bottom portion of the airtight container, the ceiling portion and the dispersion plate. A space between the bottom and the dispersion plate, so as to connect the space between the bottom and the dispersion plate, a ventilation pipe provided in the closed container, a valve provided in the middle of the ventilation pipe, the sealing A vibrating machine for vibrating the container, forming a powdery particle layer on the dispersion plate, vertically vibrating the closed container by the vibrating machine, and, with this vibration A fluidizing device for a granular material layer, wherein the granular material layer is fluidized by controlling the flow of gas in a closed container by opening and closing a valve of the ventilation pipe. 4. An airtight container, provided between the vicinity of the ceiling and the vicinity of the bottom of the inside of the airtight container, and open toward the ceiling and the bottom, respectively.
The airtight pipe thereby connecting the space near the ceiling and the space near the bottom, a valve provided in the middle of the air vent pipe, and a shaker for vibrating the airtight container, the airtight container Fill the bottom of the vent pipe with a layer of powder on the bottom.
The vibration vessel vibrates the closed container in the vertical direction, and the flow of gas in the closed container caused by the vibration is controlled by opening and closing the valve of the ventilation pipe. The fluidizing device for a granular material layer, wherein the granular material layer is fluidized by 5. The fluidizing device for a granular material layer according to claim 3, wherein opening / closing of the valve is controlled in synchronization with vibration of the vibrator. 6. An apparatus for treating combustion ash, which comprises the apparatus according to claim 3.