JP3056916B2 - Granulation control device using fluidized bed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granulation control device utilizing a fluidized bed, and more particularly, to a rotary disk having a gas outlet formed at the bottom of a casing, which is provided with a gas flow blown from the gas outlet. In a granulating apparatus utilizing a fluidized bed in which a granulated raw material from a supply unit is put into a fluidized bed state and a binder is sprayed from a binder ejecting mechanism provided in an upper space of the casing to granulate the fluidized bed, Bed height detecting means for detecting the height, gas ejection amount adjusting means for adjusting the gas ejection amount from the gas ejection port, and maintaining the upper surface height of the fluidized bed detected by the bed height detection means constant. Thus, the present invention relates to a granulation control device using a fluidized bed, comprising a granulation control means for controlling the gas ejection amount adjusting means.

[0002]

2. Description of the Related Art When various types of granulation processes are performed using the above-described granulating apparatus, the mass increases as the granules grow due to the binding of the granulated raw materials by the binder sprayed from the binder ejection mechanism. In order to maintain the fluidized bed state against the above, it is necessary to increase the gas ejection amount from the gas ejection port. For this purpose, the conventional granulation control device using a fluidized bed uses the upper surface height of the fluidized bed detected by the bed height detecting means as an index to adjust the gas ejection amount, and keeps the value constant. Thus, granulation control means for controlling granulation is provided. Monitoring of the state of the fluidized bed during the granulation process relies on changes in the height of the upper surface of the fluidized bed by the bed height detection means and visual observation by the operator. However, the fluidized bed state was recovered by manually increasing the amount of gas ejected from the gas ejection port more than usual. Here, the collapse of the fluidized bed state means that, as shown in FIG. 6, a lump is partially generated due to the disorder of the spray state of the binder from the binder ejection mechanism, and the lump grows and finally forms. The blocking state where the granular material escapes from the fluidized bed state to the overall mass,
As shown in FIG. 5, when the degree of wetness in the fluidized bed rises, a passage for ejected gas from the gas outlet is generated in the fluidized bed, and therefore, an air flow for maintaining a normal fluidized state is generated. It means that the granulated material comes out of the fluidized bed state and finally forms a channeling state that leads to the whole mass.When such a situation occurs, the operation stops and the granulated material must be discarded. is there.

[0003]

The method of applying the change of the upper surface height of the fluidized bed by the above-described bed height detecting means to the monitoring of the fluidized bed state in the granulation process involves the occurrence of a blocking state or a channeling state. In the normal state, the layer height can be detected for the first time when the layer height decreases despite securing the required amount of gas ejection from the gas outlet to maintain the layer height constant. As shown in FIG. 6, depending on the mode of the blocking state or the channeling state, the decrease in the layer height may not be detected by the layer height detecting means. On the other hand, it is difficult to quickly detect the initial stage of the occurrence of the blocking state or the channeling state by using the operator's visual observation, so that when the collapse of the fluidized bed state is found, it cannot be recovered anymore. There was a possibility that it was progressing. The present invention has been made by paying attention to such a situation, and detects a collapse of a fluidized bed state in a granulation process at an early stage, and can automatically recover a normal fluidized bed state. An object of the present invention is to provide a granulation control device for use.

[0004]

In order to achieve this object, a characteristic configuration of a granulation control device utilizing a fluidized bed according to the present invention is to provide an abnormal occurrence detecting means for detecting collapse of a fluidized bed state. An emergency control means for controlling the gas ejection amount adjusting means so as to temporarily increase the gas ejection amount when the abnormality occurrence detection means detects the collapse of the fluidized bed state is provided. In the above configuration, it is preferable that the abnormality occurrence detecting means is a pressure detecting means for detecting a sharp decrease in pressure loss in the fluidized bed. Further, it is preferable that the abnormality occurrence detecting means is an elastic wave detecting means for detecting a sudden decrease in energy of the elastic wave caused by the collision of the granulated material.

[0005]

When the abnormality detection means detects the collapse of the fluidized bed state such as the blocking state or the channeling state, the emergency control means sends a gas ejection amount adjustment means
By temporarily abruptly increasing the jetting volume to an amount larger than required to maintain a constant bed height, the blocking state and the channeling state are eliminated and the state of the fluidized bed is restored to a normal state. Here, the abnormality occurrence detecting means is a pressure detecting means for detecting a sudden drop in pressure loss in the fluidized bed due to a blocking state or a channeling state occurring in the fluidized bed, thereby indirectly controlling the collapse of the fluidized bed state. Although it is a target, it can be detected early. Further, as an abnormality occurrence detecting means, the blocking state or the channeling state occurring in the fluidized bed, the motion state of the granulated material in the fluidized bed is reduced, the sudden energy of the elastic wave generated by the collision of the granulated material. By using the elastic wave detecting means for detecting by the decrease, the collapse of the fluidized bed state can be detected directly and very early.

[0006]

According to the present invention, there is provided a granulation control apparatus utilizing a fluidized bed capable of detecting collapse of a fluidized bed state in a granulation process at an early stage and automatically recovering a state of a fluidized bed. Can now be offered.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, in the granulating apparatus utilizing a fluidized bed according to the present invention, a cone whose upper surface protrudes upward is formed at the bottom of a cylindrical granulating vessel 1 whose upper portion is slightly larger than its lower portion. The rotating disk 10 formed on the surface is rotatably mounted around the vertical axis of rotation in the granulation container 1, and the space above the upper conical surface of the rotating disk 10 is used as the granulating unit 3. In the granulating section 3, the granulated raw material is made into a fluidized bed state by airflows blown out from a plurality of gas outlets 10 a formed in the rotating disk 10, and a binder blowing mechanism provided in a space above the granulating vessel 1. 8, the binder is sprayed and granulated.

A supply mechanism 15 for supplying a raw material powder of the granulated raw material is provided at a middle stage of the granulation container 1 (specifically, an enlarged portion of the granulation container 1). The raw material powder from the supply mechanism 15 is temporarily stored in the granulating unit 3, and the stored material is made into a fluidized bed state to perform granulation.

A blower 4 having an air filter 4a provided with a damper mechanism 21 capable of adjusting the air flow is provided on the side of the granulation container 1 as a gas blowing amount adjusting means. After being heated, the gas outlet 1
Air is supplied to the granulating unit 3 through the air inlet 0a.

The binder jetting mechanism 8 is provided in the granulating container 1.
The upper end supply portion 8a (the downstream end of the pipe from the compressed air supply device 6 and the binder supply device 7 is connected to the upper end supply portion 8a disposed so as to pass through the filtration portion 2 attached to the uppermost portion of the ), And a lower end spraying portion 8b which is sprayed and supplied to the granulating portion 3 by a nozzle 8c opened at a lower part in the granulating container 1 (the portion is directed toward the granulating portion 3). Functioning as a spray port for spraying a binder) is disposed in the center of the granulation container 1 in a vertical posture. That is, while supplying the binder from the binder supply device 7, the compressed air from the compressed air supply device 6 is sprayed and supplied to the granulation section 3 by the nozzle 8c as the carrier gas.

Further, the filtration unit 2 includes the granulation container 1
An exhaust device 9 for providing a filter 2a for filtering suction / exhaust air from the inside and discharging the suction / exhaust gas to the outside of the apparatus;
The filter 2 is provided with a blow tube 2b for blowing compressed air to the filter 2a for cleaning the filter 2a.

The rotating disk 10 is rotatably mounted around a vertical axis of rotation by a driving force of a motor 13 disposed below the granulating container 1. The air supplied from the blower 4 introduced through the gas outlet is blown out to the granulating unit 3 through the gas outlet 10a.

The above-mentioned granulating apparatus is provided with a granulating control device for adjusting an optimal air volume to be blown to the granulating section 3 in order to granulate to a target particle diameter. As shown in FIG. 1, the granulation control device includes a bed height detecting unit 20 using ultrasonic waves for detecting the height of the upper surface of the fluidized bed;
gas ejection amount adjusting means 21 for adjusting the amount of gas ejection from a
And computer-assisted granulation control means 22 for granulating by adjusting the gas ejection amount adjustment means 21 so as to maintain the upper surface height of the fluidized bed detected by the bed height detection means 20 constant. Further, an abnormality occurrence detection means 23 for detecting the collapse of the fluidized bed state is provided, and when the abnormality occurrence detection means 23 detects the collapse of the fluidized bed state, the amount of gas ejected is temporarily increased suddenly. Thus, an emergency control means for controlling the gas ejection amount adjusting means 21 is provided.

The abnormality occurrence detecting means 23 is provided in the granulation container 1.
And an elastic wave detecting means for detecting an elastic wave generated by a collision between the granulated materials in the chamber and a collision between the granulated material and the rotating disk or the inner wall of the granulation container 1. Is fixedly installed via an attachment member made of metal on the outer wall in the area where is formed. The elastic wave detecting means selectively amplifies, by an amplifier, a signal of a specific frequency generated by the collision of the granulated material from the elastic wave detected by the piezo effect piezoelectric element, and generates a signal generated within a unit time (the number of collisions and the positive number). (With correlation).

The granulation control means 22 includes a computer 2
2e, a buffer circuit 22b for inputting a detection signal from the layer height detection means 20, and the abnormality occurrence detection means 23
A buffer circuit 22a for inputting a detection signal from the CPU, a driver circuit 22d for driving the gas ejection amount adjusting means 21,
A peripheral circuit such as a driver circuit 22c for driving the binder ejection mechanism 8 is provided.

As shown in FIG. 3, the granulation control means 22
First, the computer 22e, which is a component of the apparatus, injects the raw material powder from the supply mechanism 15 into the granulating section 3 and sets the gas ejection amount adjusting means 2 so that the stored material is in a fluidized bed state.
1: Open the damper. The opening degree of the damper is set until the output of the layer height detecting means 20 reaches a set value. Thereafter, while the binder is spray-supplied from the binder supply device 7, the granulation is carried out together with the growth of the particle size. As the height decreases, the opening degree of the damper is gradually increased to maintain the layer height constant. Here, the layer height value to be adjusted is an arbitrary value set in advance by the granulation target. On the other hand, the output value of the elastic wave detecting means shows a tendency to decrease as the amount of air blown from the gas ejection amount adjusting means 21 which was initially excessively large as the granulation progresses gradually becomes an appropriate amount. When the fluidized bed state is disrupted due to the occurrence of a blocking state or a channeling state, the bed height detecting means 20
, The output value of the elastic wave detecting means always drops. Therefore, the computer 22e activates the emergency control means, which is a switch circuit for switching between the control signal in the normal control state and the control signal in the emergency state, so as to sharply increase the opening degree of the damper of the gas ejection amount adjusting means 21. By adjusting the wind pressure, the blocking state and the channeling state are eliminated at an early stage of the occurrence. At this time, the opening of the damper does not need to be the maximum opening, but is a value that can secure a sufficient air flow to eliminate the blocking state and the channeling state, and the output value of the elastic wave detecting unit is abrupt. It returns to a value substantially equal to the previous value indicating the decrease, and the layer height detecting means 2
If the output of 0 is decreasing at the same time, the opening is maintained until the value returns to a value substantially equal to the previous value indicating the decrease. After returning to the normal state, the opening of the damper is adjusted again so that the output of the layer height detecting means 20 is maintained at the set value. Adjustment control of the gas ejection amount adjustment means 21 in the normal state by the computer 22e
PID control based on the output of the layer height detection means 20, or fuzzy control or AI control provided with an inference mechanism can be used as appropriate.

Another embodiment will be described below. In the above embodiment, the elastic wave detecting means is configured to output the number of elastic waves generated in a unit time, but as the elastic wave detecting means, the elastic wave detecting means The product of the number and its intensity may be output as energy. In the above embodiment, the single elastic wave detecting means is fixedly installed on the outer wall of the granulation vessel 1 in the range where the granulation layer is formed via the metal attachment member.
If the output of any one of the elastic wave detecting means is significantly lower than the output of the other elastic wave detecting means, the fluidized bed state is partially collapsed by mounting a plurality of pieces along the outer wall periphery. Can be detected. In the above embodiment, the abnormality occurrence detecting means 23 using the elastic wave detecting means for detecting a sudden decrease in the energy of the elastic wave caused by the collision of the granulated material has been described. As shown in FIG. 4, a pressure detecting means for detecting a rapid decrease in pressure loss in a fluidized bed may be used.
That is, the pressure detecting means is configured by arranging a pressure sensor for detecting a pressure difference between the lower part and the upper part of the fluidized bed, that is, a pressure loss, in a bypass pipe connecting the lower part and the upper part of the fluidized bed, This is to identify that the state of the fluidized bed has collapsed by utilizing the fact that much of the airflow supplied into the fluidized bed due to the channeling phenomenon or the blocking phenomenon passes through and the pressure drop value sharply decreases. The lower opening of the bypass pipe may be arranged between the rotating disk 10 and the perforated plate of the air outlet provided thereunder, so that the pressure loss due to clogging of the perforated plate or the like may be reduced. The effect can be eliminated.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a granulating apparatus.

FIG. 2 is a block diagram of a granulation control device.

FIG. 3 is a control timing chart of a granulation control device.

FIG. 4 is a block diagram of a main part showing another embodiment.

FIG. 5 is an explanatory diagram of channeling reduction.

FIG. 6 is an explanatory diagram of blocking reduction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Granulation container 8 Binder ejection mechanism 10a Gas ejection port 20 Layer height detection means 21 Gas ejection amount adjustment means 22 Granulation control means 23 Abnormality detection means

Claims (3)

(57) [Claims] 1. A granulation raw material is made into a fluidized bed state by an air flow ejected from a gas ejection port (10a) provided at the bottom of a granulation container (1), and is placed in a space above the granulation container (1). A bed height detecting means (20) for detecting the height of the upper surface of the fluidized bed to be granulated by spraying the binder from the provided binder ejection mechanism (8).
A gas ejection amount adjusting means (21) for adjusting the gas ejection amount from the gas ejection port (10a); and a constant upper surface height of the fluidized bed detected by the bed height detection means (20). And a granulation control means (22) for controlling the gas ejection amount adjusting means (21) as described above, wherein the abnormality occurrence detection means (U) detects the collapse of the fluidized bed state. 2
3) is provided, and when the abnormality occurrence detecting means (23) detects the collapse of the fluidized bed state, the emergency control for controlling the gas ejection amount adjusting means (21) so as to temporarily increase the ejection amount of gas temporarily. A granulation control device using a fluidized bed provided with a means. 2. The granulation control device using a fluidized bed according to claim 1, wherein the abnormality occurrence detecting means is a pressure detecting means for detecting a sudden decrease in pressure loss in the fluidized bed. 3. The granulation using a fluidized bed according to claim 1, wherein the abnormality occurrence detecting means (23) is an elastic wave detecting means for detecting a sudden decrease in energy of the elastic wave caused by the collision of the granulated material. Control device.