JP2001212448A - Method and device for fluidizing powder and granular material bed in hermetic vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a fluidized bed which obviates the dissipation of raw materials, such as powder and granular materials constituting the fluidized bed, to be subjected to a heat treatment, by using the fluidized bed, facilitates atmosphere regulation and is capable of executing the treatment in a uniform heating place by fluidizing the powder and granular material bed in a hermetic vessel and executing the formation of the fluidized bed. SOLUTION: This method for fluidizing the powder and granular material bed in the hermetic vessel consists in providing the hermetic vessel with a gas introducing means for introducing gas into the powder and granular material bed, a communicating means having a valve for communicating the gas introducing means with the ceiling section on the inner side of the hermetic vessel or near the same and an exciting means for vibrating the hermetic vessel and consists in fluidizing the powder and granular material bed by vibrating the hermetic vessel by the exciting means and controlling the flow of the gas in the hermetic vessel generated by accompanying the vibration by opening and closing of the valve of a vent pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A fluidized bed formed by introducing an airflow into a granular material layer composed of various powders and particles and fluidizing the fluidized bed is used in a chemical industry or the like to dry raw materials or to generate fuel for power generation and the like. It is widely used for combustion, various reactions using a catalyst, granulation and coating, and the like.

[0003] In the above-mentioned fields, particularly when a fluidized bed is formed in a step of performing a heat treatment for drying or the like, if the powder or granules forming the fluidized bed can be fluidized in a closed system. There is no dissipation of the powder or granules constituting the fluidized bed or the raw materials for heat treatment, etc., and the atmosphere adjustment is easy.
It is possible to quickly obtain a more uniform heating field.

[0004] In recent years, treatment of dioxin generated during incineration of refuse has become a major problem. It is known that dioxin contained in combustion ash at the time of 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 carry out the treatment in a closed system in order to improve the treatment efficiency and also from the viewpoint of safety.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to propose a method for efficiently forming a fluidized bed in a closed vessel.

[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 gas into the granular material layer and a valve in the closed container. And, while providing a communication means for communicating between the gas introduction means and the ceiling portion or the vicinity of the ceiling inside the closed vessel, and a vibration means for vibrating the closed vessel, a valve is provided for the communication means, The closed container is vibrated in the vertical direction by the vibrating means, and the flow of gas in the closed container caused by the vibration is controlled by opening and closing a valve provided in the communication means, through the gas introducing means. The method is characterized in that the granular material layer is fluidized by being introduced into the granular material layer.

The method according to the invention is characterized in that the fluidization of the granules is effected in a closed vessel by vibrating the vessel and thus the inertial movement of the granules, causing a flow in the gas in the closed vessel, and Is appropriately controlled. Therefore, since a fluidized bed can be formed without introducing a gas from the outside, when performing a heat treatment or the like using a fluidized bed, there is no dissipation of the powder or granules constituting the fluidized bed or a raw material for performing the heat treatment,
The atmosphere can be easily adjusted and a uniform heating field can be obtained. In addition, since the treatment is performed in a closed system, it is particularly suitable for a heat treatment in an oxygen-free atmosphere and a decomposition treatment of harmful substances, for example, dioxin contained in combustion ash of refuse.

The method for fluidizing a granular material layer in a closed container according to the present invention is characterized in that the opening and closing of the valve is controlled in synchronization with the vibration of the vibrator. Thereby, the flow of the gas generated by the vibration of the container and thereby the inertial movement of the granular material can be more appropriately controlled.

[0009] The present invention also relates to an apparatus for forming a fluidized bed by fluidizing a granular layer.

That is, the fluidizing apparatus for a granular material layer according to the present invention is arranged such that a space of a predetermined size is provided between a ceiling portion and a bottom portion inside the closed container and inside the closed container. Dispersion plate, a space between the ceiling and the dispersion plate, so as to connect a 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, and a vibrator for vibrating the closed container, a powder layer is formed on the dispersion plate, and the closed container is vertically moved by the vibrator. The method is characterized in that the granular material layer is fluidized by vibrating and controlling the flow of gas in the closed container caused by the vibration by opening and closing a valve of the ventilation pipe.

The fluidizing apparatus for a granular material layer according to the present invention is provided between an airtight container and a vicinity of a ceiling and a bottom inside the airtight container, and opens toward the ceiling and the bottom, respectively. A vent pipe thereby communicating the ceiling with the bottom, a valve provided in the middle of the vent pipe,
A vibrator for vibrating the closed container.

The fluidizing apparatus for a granular material layer according to the present invention is characterized in that the fluidized bed is formed by generating a flow in the gas in the closed container by the vibration of the container and the inertial motion of the granular material in the closed container. And by appropriately controlling the flow. Therefore, the fluidized bed can be formed without introducing a gas from the outside.Therefore, there is no dissipation of the powder and granules constituting the fluidized bed and the raw materials for performing the heat treatment, etc. Processing can be performed. In addition, since the treatment is performed in a closed system, the present invention is particularly suitable for a heat treatment in an oxygen-free atmosphere and a decomposition treatment of harmful substances, for example, dioxin contained in combustion ash of refuse.

Further, the fluidizing apparatus for a granular material layer according to the present invention is characterized in that the opening and closing of the valve is controlled in synchronization with the vibration of the vibrator. Thereby, the vibration of the container and
As a result, the flow of gas generated by the inertial motion of the granular material can be more appropriately controlled.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an apparatus for fluidizing 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. A dispersion plate 14 having air permeability is provided in the closed container 11, and a powder layer 15 is formed on the dispersion plate 14. Further, between the granular material layer 15 and the ceiling of the closed container 11, a granular material stopper 16 for suppressing an excessive rise of the granular material is provided. The ventilation pipe 13 is provided so as to communicate a space 17 above the dispersion plate provided in the closed container 11 with a space 18 below the dispersion plate, and a valve 19 is provided in the middle. The upper space is divided by a powder stopper 16 into a powder moving part 17a and a gas reservoir 17b. The valve 19 includes a steel ball 20, a pedestal 21, and a stopper 22. When the steel ball 20 is seated on the pedestal 21, gas flow in the ventilation pipe 13 is prevented. Also, stopper
Numeral 22 regulates 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 powdery and granular materials are introduced into the closed container 11 of the apparatus 10 of FIG. 3 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 at the time of conducting the experiment are as shown in Table 2 below.

[0017]

[Table 1]

[0018]

[Table 2]

In FIG. 2B, 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 of space (gas reservoir) 17b_UPressure difference ΔP = P_L
−P _UIndicated by.

FIG. 2A shows a container 11, a granular material layer 15, and a steel ball 20.
And the time change of each of the vibration acceleration of the container, and the bottom dead center of the container 11, that is, the position at the time of rest before the vibration is set to 0 in the figure.

As shown in FIG. 2A, when the container 11 is vibrated up and down 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.
When the container 11 rises, the acceleration decreases. When the acceleration reaches the point A1 in the figure, the acceleration of the container 11 becomes smaller than the gravitational acceleration -g, so that the powder layer 15 and the steel balls 20 move with respect to the container 11. Surface. As a result, the gas (air) in the space 17 above the dispersion plate 15 is pushed by the granular material layer, and flows into the lower space 18 through the ventilation pipe 13. Here, FIG. 2 (b), the namely the pressure P _L of the lower space 18 of the dispersion plate 15, looking at the differential pressure ΔP between the pressure P _U in the upper space (gas reservoir) 17b, containers 1
The differential pressure ΔP is 0 from the bottom dead center O to A1 of 1, but A1
, The differential pressure ΔP is negative. This is nothing but an indication that the above-mentioned gas movement has occurred.

Next, when the container 11 is further raised, FIG.
At the point B1 in FIG. 7A, 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 11 remains in contact with the stopper 22. Exercise with. Thereafter, after the point C1, the container 11
Is greater than the gravitational acceleration -g.
20 descends relative to container 11. On the other hand, the granular material layer 15
After one point, it continues to rise further due to inertia. for that reason,
A ventilation pipe from the upper space 17 of the distribution plate 15 to the lower space 18
Gas movement through 13 also continues. After that, the granular material layer 15
The lowering of the container 11 is started between the point C1 and a point D1 described later.

When the container 11 descends and reaches the point D1, a steel ball
20 sits on a pedestal 21 and closes the ventilation pipe 13. Also the granular material layer 15
Is lowered with respect to the container 11, so that the air in the lower space 18 is compressed. Therefore, the differential pressure ΔP rapidly increases as shown in FIG. 2B and reaches a peak at the point E.

Thereafter, the air in the lower space 18 is
Then, it passes through the granular material layer 15 and moves to the upper space 17. As a result, the differential pressure ΔP decreases, 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 the point E and the point A2 is due to a balance between the lowering of the granular material layer and the passage of air through the granular material layer. It is.

Further, the container 11 changes from descending to ascending and A
When two points are reached, the acceleration of the container 11 again becomes the gravitational acceleration-g
Therefore, the granular material layer 15 and the steel balls 20 float on the container again. 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 to the lower space.
Move to 18. In FIG. 2B, the differential pressure Δ
That is why P rapidly decreases to a negative value.
By repeating the above process, a fluidized bed is formed.

The above process is more specifically described as follows. FIG. 3 shows the state inside the container 11 in the process from A1 to B1 to C1 in FIG. At this time, since the acceleration a of the container 11 is smaller than the gravitational acceleration -g (see FIG. 2A), the granular material layer 15 rises from the dispersion plate 14,
The steel ball 20 also rises from the pedestal 21. So the upper space
The air in 17 is pushed and flows through the ventilation pipe 13 to the lower space 18. In this drawing, the granular stopper 16 is omitted.

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, and the granular material layer 15 descends with respect to the container 11, and the steel ball 20 similarly descends and sits on the pedestal 21. Therefore, the air flow in the ventilation pipe 13 is shut off, and the air in the lower space 18 is
15 will be compressed. Therefore, FIG.
As shown in (b), the differential pressure ΔP rises sharply.

FIG. 5 shows a state inside the container 11 from when the container 11 descends from the point D1 to reach the bottom dead center, and then turns upward and reaches A2. Also at this time, since the acceleration a of the container is still larger than the gravitational acceleration -g, the granular material layer 15 continues to descend, but the air in the lower space 18 causes the dispersion plate 14 and the granular material layer 15 to move. It passes through and flows into the upper space 17. As a result, the air passing through the granular material layer 15 generates a large number of bubbles 23 inside the granular material layer 15 and fluidizes the air. As a result, a fluidized bed is formed.

FIG. 6 shows the state of the granular material layer inside the vessel in a fluidized bed formation experiment conducted using the apparatus shown in FIG. Here, FIG. 6 (a) shows that the container has a frequency of 2.8.
FIG. 6B shows a case where the vibration is performed at a frequency of 3.1 Hz.

As shown in FIG. 6A, 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 Has no significant ripples. That is, it is understood that a good fluidized bed is formed. On the other hand, as shown in FIG.
It can be seen that when vibrating at 3.1 Hz, large undulations are generated on the surface of the granular material layer 42 in the container 41.

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

As shown in FIG. 7, regardless of the height of the granular material layer, a sharp increase in the differential pressure ΔP is observed from around time t = 0.13 sec. For this reason, in the present device 10, the time t = 0.
In 13 sec, the steel ball 20 of the valve 19 is seated on the pedestal, ie, FIG.
It is understood that the state shown in FIG. Next, the pressure difference ΔP reaches a peak and then decreases sharply. At this time, it is confirmed that air bubbles are generated in the granular material layer and a fluidized bed as shown in FIG. 6 (a) is formed. I have. That is, the differential pressure Δ
While P sharply decreased from the peak, air flowed through the granular layer, thereby forming a fluidized bed (see FIG. 5).
This indicates that the differential pressure ΔP has decreased. Thereafter, at t = 0.35 sec, the pressure difference ΔP sharply decreases again. This is because the upward acceleration of the container becomes smaller than the gravitational acceleration −g again, as shown in FIG. It indicates that it will rise again away from 22.

Here, comparing FIG. 7 with FIG. 2, FIG.
Has a tendency similar to the change in the differential pressure ΔP shown in FIG. From this, it is understood that in the present apparatus 10, a fluidized bed is formed irrespective 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, no fluidized bed is formed.

FIG. 8 shows the peak of the pressure difference ΔP with respect to the frequency of the container for the granular material layers having different heights (FIG. 2 (b)
E point). 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 material layer. This indicates that in the present apparatus 10, the steel ball 20 of the valve 19 floats away from the pedestal 21 and has the lowest frequency reaching the stopper 22. The differential pressure ΔP is
It has been confirmed that the tendency of the peak value to increase in frequency around 2,4 Hz becomes gentle, and that a fluidized bed as shown in FIG. 6A is formed simultaneously. However, after 3.0 Hz, when the height of the granular material layer is 105 mm and 88 mm, the peak value of the differential pressure ΔP has started to decrease. This is because the surface of the granular material layer was wavy as shown in FIG. 6 (b), and air flowed through a portion where the height of the layer was relatively reduced.

From this, it can be seen that the change in the differential pressure ΔP
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 and the granular material layer depend on the frequency of vibration of 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 optimal fluidized bed formation depending on the height of the bed.

FIG. 9 shows another example of an apparatus for fluidizing a 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 device 50, a plurality of vent pipes 53 (three of them are shown in the figure) are provided in the closed vessel 51, and each of these vent pipes opens toward the ceiling and the bottom of the closed vessel 51, respectively. And a valve 54 is provided for each. The valve 54 comprises a steel ball 55, a pedestal 56 and a stopper 57, as in the case of the apparatus of FIG. Further, a dispersion plate as in the apparatus 10 of FIG. 1 is not provided in the closed container 51, and the granular material layer 58 is formed by being spread on the bottom of the closed container 51. A powder stopper 59 is provided between the powder layer 58 and the ceiling of the closed container 51, and the vent pipe 53 is provided.
The upper end 53a projects upward from the granular material stopper 59. The powder layer 58 is formed so as to bury the lower end 53b of the ventilation pipe 53.

As described above, the apparatus 50 of FIG. 9 is not provided with a dispersing plate as in the apparatus 10 of FIG. 1, but instead, the ventilation pipe 53 also serves as a dispersing plate. That is, when the steel container 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 below the raised granular material layer 58.

As described above, according to the present invention, since a fluidized bed can be formed in a closed vessel, the powdery material constituting the fluidized bed and the raw material for performing heat treatment or the like using the fluidized bed are used. And the atmosphere can be easily adjusted, and the treatment can be performed in a uniform heating field. In addition, since the treatment is performed in a closed system, it is particularly suitable for a heat treatment in an oxygen-free atmosphere and a decomposition treatment of harmful substances, for example, dioxin contained in combustion ash of refuse.

It should be noted that the present invention is not limited to the above-described embodiment, and various forms are possible. For example,
In the examples shown in FIGS. 1 and 9, the valve is composed of a steel ball, a pedestal, and a stopper. However, various other types of valves can be used in the device according to the present invention. In particular, by using an electromagnetic valve or the like and synchronizing it with the vibration of the closed vessel and performing appropriate control, a more efficient fluidized bed can be formed. Also, 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 possible not to provide a powder stopper.

[Brief description of the drawings]

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

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

FIG. 3 is a view schematically showing movements of a granular material layer and a steel ball in the container of FIG.

FIG. 4 is a view schematically showing movements of a granular material layer and a steel ball in the container of FIG.

FIG. 5 is a view schematically showing movements of a granular material layer and a steel ball in the container of FIG. 1;

FIG. 6 is a photograph showing the movement of the granular material layer in the container of FIG. 1;

FIG. 7 is a graph showing a temporal change of a differential pressure in a container in a granular material layer having different heights.

FIG. 8 is a graph showing a change in a differential pressure with respect to a frequency of a container in powdery 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 device 11, 51 Closed vessel 12, 52 Shaker 13, 53 Ventilation pipe 14 Dispersion plate 15, 58 Powder layer 16, 59 Powder stopper 17 Space above dispersion plate 18 Dispersion plate Lower space 19,54 Valve 20,55 Steel ball 21,56 Base 22,57 Stopper

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D004 AA36 AB07 CA24 CB08 DA02 DA06 4G070 AA01 AB04 BB23 BB32 CA03 CA12 CA16 CA24 CA30 CB02 CB03 CB10 CB15 CB25 DA05 DA23 5D107 AA03 BB20 DD07 DE02

Claims (6)

[Claims] The fluidized powder layer formed in the closed container has a gas introducing means for introducing gas into the powder layer, and a valve. Communication means for communicating between the gas introduction means and the ceiling portion or the vicinity of the ceiling inside the closed vessel; and vibrating means for vibrating the closed vessel, wherein the closed vessel is vibrated vertically by the vibrating means. And, by introducing the flow of gas in the closed container caused by this vibration into the granular material layer through the gas introduction means while controlling by opening and closing a valve provided in the communication means, A method for fluidizing a granular material layer in a closed container, comprising: 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 shaker. 3. An airtight container, a dispersion plate disposed inside the airtight container so as to provide a space of a predetermined size between a ceiling and a bottom thereof, and the ceiling and the dispersion plate, A vent pipe provided in the closed container so as to connect a space between the bottom part and the space between the bottom plate and the dispersion plate; a valve provided in the middle of the vent pipe; A vibrator for vibrating the container, forming a granular material layer on the dispersion plate, vibrating the closed container vertically by the vibrator, and the vibration caused by this vibration An apparatus for fluidizing a granular material layer, characterized by fluidizing the granular material layer by controlling the flow of gas in a closed vessel 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 inside the airtight container, and opened toward the ceiling and the bottom, respectively.
A ventilation pipe for communicating the space near the ceiling with the space near the bottom, a valve provided in the middle of the ventilation pipe, and a vibrator for vibrating the closed vessel; Forming a granular material layer on the bottom, vibrating the sealed container in the vertical direction by the vibrator, and opening and closing the valve of the ventilation pipe with the flow of gas in the sealed container caused by the vibration. A fluidizing device for a granular material layer, characterized in that the granular material layer is fluidized by controlling the fluidized particle layer. 5. The fluidizing device for a granular material layer according to claim 3, wherein opening and closing of the valve are controlled in synchronization with vibration of the vibrator. 6. An apparatus for treating combustion ash, comprising an apparatus according to any one of claims 3 to 5.