JP3056917B2 - 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 apparatus utilizing a fluidized bed, and more particularly, to a rotary disk having a gas ejection port provided at the bottom of a granulation vessel and ejected from the gas ejection port. The granulation raw material from the supply unit is made into a fluidized bed state by an air flow, and a binder is sprayed and granulated by a binder ejecting mechanism provided in an upper space of the granulation container to form a granulation apparatus using a fluidized bed. It relates to a grain control device.

[0002]

2. Description of the Related Art Conventionally, a bed height detecting means such as an ultrasonic sensor for detecting the height of a top surface in a fluidized bed is provided, and the top height detected by the bed height detecting means is kept constant in a granulation process. Granulation control means for controlling the gas ejection amount adjusting means for adjusting the amount of air blown from the gas ejection port so as to maintain the air flow rate.

[0003]

However, in the above-mentioned conventional granulation control device utilizing a fluidized bed, the optimum fluidized state in the process of growing the granules by combining the granulated raw materials by the sprayed binder, Since it was not possible to grasp directly in the granulation process, as shown in FIG. 4, a fluidized bed (granulated material) which seems to be optimal for the granulated material having a particle size in the final stage of granulation is used. The gas is blown out so that the bed height is always maintained from the initial stage, based on the bed height when the necessary amount of gas is blown out to maintain the fluidized bed state in which the bed is not destroyed by collision etc. Since the amount was adjusted,
In the granulation process up to the final stage, the gas was ejected in an amount equal to or greater than the gas ejection amount necessary to obtain an optimal flow state. Therefore, the momentum of the granulated material at the intermediate stage becomes equal to or more than the momentum required for granulation, and when the granulated materials collide with each other, the grown granulated material is destroyed in reverse, and the granulation speed is reduced. In addition to the decrease, there is a fear that the dispersion of the particle size of the final granulated product becomes large. Therefore, it has been proposed that the optimum state of the fluidized bed from the initial stage to the final stage of granulation is grasped in advance by experiments and the like, and computer-controlled program control for automatically changing the gas ejection amount according to the pattern is proposed. However, in this case, the spray amount and the spray state of the binder fluctuate due to failure of the binder ejection mechanism or the like, or
If the degree of particle growth is disturbed due to other factors, there is a drawback that it is impossible to respond. An object of the present invention is to increase the granulation speed even when there is some variation in the spray amount or spray state of the binder from the binder ejection mechanism, and
An object of the present invention is to provide a more excellent granulation control device using a fluidized bed for reducing the variation in the particle size of the final granulated product and increasing the product yield.

[0004]

According to the present invention, a granulation control apparatus using a fluidized bed is characterized by a bed height detecting means for detecting the height of the upper surface of the fluidized bed, and gas ejection from the gas ejection port. A gas ejection amount adjusting means for adjusting the amount, and a pressure detecting means for detecting a pressure loss value in the fluidized bed, wherein the granulated raw material has an upper surface height before the fluidized bed state and an upper surface height of the fluidized bed. Granulation control means for controlling the gas ejection amount adjusting means so as to maintain the product of the difference between the layer expansion height and the pressure loss value at a constant value.

[0005]

The layer expansion height, which is the difference between the upper surface height before the granulated raw material enters the fluidized bed state and the upper surface height of the bed after the fluidized bed state, is defined as ΔL [m]. Assuming that the pressure loss value between the lower surface and the lower surface is ΔP [Kg / m ² ] and the bottom area of the fluidized bed is A [m ² ], the product A · ΔP · ΔL [K
g · m] represents the kinetic energy [J] of the particles forming the fluidized bed. Therefore, in the granulation process,
In order to keep the kinetic energy [J] of the particles constant,
In other words, if the blowing rate is adjusted so as to keep ΔP · ΔL constant, for example, in the early stage of granulation, small-mass particles are moved at a high speed to promote the growth of the particles, and at the end of granulation, Even if the degree of particle growth is disturbed by some factor, such as moving large particles at a slow speed to suppress particle destruction due to collision between particles, appropriate The air volume can be controlled.

[0006]

According to the present invention, the optimum granulation can be achieved even when the degree of particle growth is disturbed, such as a change in the amount of the binder sprayed from the binder ejection mechanism or a change in the spraying state. Better granulation using a fluidized bed to reduce the variation in the particle size of the final granulated product and increase the product yield, because it can avoid the destruction due to collisions at the stage of particle growth at high speed. A control device can now be provided.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the granulating apparatus using a fluidized bed according to the present invention has a conical surface whose upper surface protrudes upward at the bottom of a cylindrical granulating container 1 whose upper part is slightly larger than its lower part. The rotating disk 10 thus mounted is rotatably mounted around the axis of rotation in the vertical direction in the granulation container 1, and the space above the conical surface of the upper surface of the rotating disk 10 is used as the granulating unit 3, and the granulating unit 3 is used. In step 3, the granulated raw material is made into a fluidized bed state by the air currents jetted from the plurality of gas jet ports 10a formed in the rotating disk 10, and the granulated raw material is combined from the binder jetting mechanism 8 provided in the space above the granulating container 1. It is configured to granulate by spraying the agent.

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 granulation 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, and is provided with an air supply port 1 a of 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 optimum 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 adjusts a bed height detecting means 20 using an ultrasonic sensor for detecting an upper surface height L in a fluidized bed, and a gas ejection amount from the gas ejection port 10a. And a pressure detecting means 23 for detecting a pressure loss value ΔP in the fluidized bed, wherein the upper surface height L0 and the upper surface height of the fluidized bed before the granulated raw material enters a fluidized bed state. Computer-assisted granulation control means 22 for controlling granulation by adjusting the gas ejection amount adjustment means 21 so as to maintain the product of the layer expansion height ΔL, which is the difference between the pressure L, and the pressure loss value ΔP at a constant value. Consists of

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, a buffer circuit 22a for inputting a detection signal from the pressure detection means 23, and a driver circuit 22d for driving the gas ejection amount adjustment means 21 And a peripheral circuit such as a driver circuit 22c for driving the binder ejecting mechanism 8.

More specifically, as shown in FIGS. 1 and 2,
The granulation control unit 22 first injects the raw material powder from the supply mechanism 15 into the granulation unit 3, and opens the gas ejection amount adjustment unit 21, that is, the damper, in order to bring the stored material into a fluidized bed state. The opening degree of the damper is set until the product of the above-mentioned layer expansion height ΔL and the pressure loss value ΔP reaches a set value, and then, while spraying and supplying the binder from the binder supply device 7, the layer expansion height The granulation is performed by adjusting the opening degree of the damper so as to maintain the product of ΔL and the pressure loss value ΔP at a set value. That is, ΔL [m] is the bed expansion height, which is the difference between the top surface height before the granulated raw material enters the fluidized bed state and the top surface height of the bed after the fluidized bed state, and the upper and lower surfaces of the fluidized bed. And ΔP [Kg / m ² ], and the bottom area of the fluidized bed is A
[M ² ], their product A · ΔP · ΔL [Kg ·
m] is the kinetic energy of the particles forming the fluidized bed [J]
Is represented. Therefore, in the granulation process, if the blast energy is adjusted so as to maintain the kinetic energy [J] of the particles constant, that is, to maintain ΔP · ΔL constant, for example, at the beginning of granulation, Some factors, such as moving small particles at high speed to promote particle growth, and at the end of granulation, moving large particles at low speed to suppress particle destruction due to collision between particles. Thus, even if the degree of particle growth is disturbed, the air flow is appropriately controlled in accordance with the particle growth stage.
As a result, as shown in FIG. 3, an excessive amount of air is not blown at each stage of granulation. Granulated in a small state.

As the control algorithm by the granulation control means 22, the layer expansion height ΔL and the pressure loss value ΔP are determined by PID control for determining the opening degree of the damper from input data, fuzzy control, and inference control utilizing a knowledge base. Etc. can be used as appropriate. Further, as the layer height detecting means 20,
In addition to an ultrasonic sensor that detects ultrasonic waves reflected from the upper surface of the layer, a pair of transmission / reception devices are attached to the opposite wall in the height direction, and light or electromagnetic waves that detect the layer height based on the presence or absence of signal detection Can also be used.

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 characteristic diagram

FIG. 4 is a conventional control characteristic diagram.

[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 L0 Upper surface height ΔL Layer expansion height ΔP Pressure loss value

Claims (1)

(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 a height (L) of an upper surface of the fluidized bed for spraying and granulating a binder from a provided binder ejection mechanism (8); A gas ejection amount adjusting means (21) for adjusting the gas ejection amount from the outlet (10a); and a pressure detection means (23) for detecting a pressure loss value (ΔP) in the fluidized bed. The product of the bed expansion height (ΔL), which is the difference between the upper surface height (L0) before the formation of the layer and the upper surface height (L) of the fluidized bed, and the pressure loss value (ΔP) is maintained at a constant value. And a granulation control means (22) for controlling the gas ejection amount adjusting means (21) to perform the granulation control using a fluidized bed. Place.