JPH10146526A - Control of granulation of powdery particles in fluidized bed treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically operate a fluidized bed treatment apparatus obtaining powdery particles having a desired particle size by measuring the particle size of powdery particles during granulation operation by a laser beam type particle size sensor to control the particle size of the powdery particles on the basis of the org. relation of a sprayed liquid droplet diameter, a binder soln. use amt. and a particle size. SOLUTION: In such a case that the operation of a fluidized bed treatment apparatus is continued under an operation condition at a time of measurement from a measured value obtained by measuring a particle size of powdery particles during granulation operation and a use amt. of a binder soln., the average particle size at a time of the spraying of the total amt. of the binder soln. is estimated and the spray liquid droplet diameter of the binder soln. is changed corresponding to the estimated value to control the particle size of powdery particles and the growth of the particle size of powdery particles is appropriately corrected corresponding to the estimated value of the average particle size at a time of the spraying of the total amt. of the binder soln. to set the particle size at the time of the spraying of the total amt. of the binder soln. to a desired value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for granulating a granular material using a fluidized bed treatment apparatus, and more particularly, to measuring a particle size of a granular material during a granulating operation with a laser beam type particle size sensor. And
The present invention relates to a granulation control method for controlling the particle diameter of a granular material by predicting the average particle diameter at the time of spraying the whole amount of the binder liquid based on the measured value.

[0002]

BACKGROUND OF THE INVENTION Fluidized bed granulation using a fluidized bed processing apparatus (fluidized bed granulation apparatus) is a method for granulating powder into fine granular particles (powder granules) in the food industry, the pharmaceutical industry, and the like. Although widely used in industry, etc., this granulation method has become widespread without establishing a basic theory of granulation, such as engineering analysis of the particle growth mechanism. Leading in the field-led form. For this reason, both the setting of the operating conditions and the operating operation for producing the granules having the desired physical properties (such as the average particle diameter) largely depend on the empirical skills of the operators, and automation is not promoted at present. It is.

[0003] The material moisture in the fluidized bed is one of the operating factors which greatly affects the quality of the granular material. In recent years, a method of online measurement and control using a near infrared moisture meter or the like has been proposed. Has been established and contributes greatly to the stable production of granulated products. Various methods have also been proposed for controlling the particle size of the granules during the granulation operation together with the value of the material moisture in the fluidized bed.

[0004] For example, a method disclosed in Japanese Patent Application Laid-Open No. 7-794 "Apparatus for performing granulation, coating, and the like" is disclosed in Japanese Patent Application Laid-Open No. 7-794. In this method, the shape, particle size and particle size distribution of the granular material are measured based on the image, and the operation of the apparatus is stopped when these values reach desired values.

Japanese Unexamined Patent Publication No. Hei 8-210962, "Image analysis method and granulation control method in a granulating apparatus" is an improvement of the invention of Japanese Unexamined Patent Publication No. Hei 7-794. In order to compensate for the insufficiency, the image processing is performed to binarize the raw image and separate the overlapping particle images by shrinkage separation, circular separation, and wedge separation means. All of these measures the moisture value in the fluidized bed when the measured value reaches the desired average particle size, together with the output of a separately provided moisture meter, and continues granulation while maintaining this moisture value. The granulating operation is stopped when each particle has a desired shape. However, an increase in peripheral devices and an increase in price due to complicated image processing are caused.

It has been recognized in manufacturing sites that the diameter of the sprayed droplets of the binder liquid sprayed into the fluidized bed is related to the growth of the particle size of the granular material, but the operator uses this relationship intuitively. In fact, no technology has been developed to actively apply it to automation.

[0007]

SUMMARY OF THE INVENTION The present invention has been made based on the recognition of such a background, and measures the particle size of a granular material during a granulating operation by a laser beam type particle size sensor. By controlling the particle size of the granular material based on the measured value and the organic relationship between the droplet diameter of the sprayed liquid and the amount of the binder liquid used and the particle size, a granular material having a desired particle size is obtained. The technical task was to develop a new granulation control method that enables automatic operation of a fluidized bed treatment device.

[0008]

According to a first aspect of the present invention, there is provided a method for controlling granulation of a granular material in a fluidized-bed processing apparatus, wherein a binder liquid is sprayed on a raw material powder flowing in a fluidized chamber. In a fluidized bed treatment apparatus for granulating the body, the particle size of the granular material during the granulation operation is measured, and from the measured value and the amount of the binder liquid used, the operating conditions of the fluidized bed treatment apparatus are measured at the time of measurement. When the operation is continued, the average particle diameter at the time of spraying the entire amount of the binder liquid is predicted, and the diameter of the spray droplets of the binder liquid is changed according to the predicted value, thereby controlling the particle diameter of the granular material. Features. According to the present invention, it is possible to appropriately correct the particle size growth of the granular material according to the predicted value of the average particle size at the time of spraying the entire amount of the binder liquid, and set the particle size at the time of spraying the entire amount of the binder liquid to a desired value. be able to.

According to a second aspect of the present invention, there is provided a method for controlling granulation of a granular material in a fluidized bed processing apparatus, wherein the particle size of the granular material during the granulating operation is measured by a laser beam type particle size sensor. And the sensing part in the laser beam type particle size sensor is made to directly face the powder or granules in the fluidized chamber. According to the present invention, since the flowing granular material is directly measured, the setting value corresponding to the state of the granular material can be changed without delay.

According to a third aspect of the present invention, there is provided a method for controlling granulation of a granular material in a fluidized-bed processing apparatus, wherein in addition to the above-mentioned requirements, the diameter of the spray droplet of the binder liquid is changed by adjusting a spray air pressure. It is characterized by the following. According to the present invention, the spray droplet diameter can be changed to a value corresponding to the predicted average particle diameter without delay.

Further, in the fluidized bed processing apparatus according to the present invention, there is provided a method for controlling granulation of a granular material.
In addition to the requirements described above, the change in the spray droplet diameter of the binder liquid is performed by adjusting the spray liquid velocity. According to the present invention, the spray droplet diameter can be changed to a value corresponding to the predicted average particle diameter without delay.

Further, according to a fifth aspect of the present invention, there is provided the method for controlling granulation of a granular material in the fluidized bed processing apparatus, wherein the measured value of the particle size of the granular material during the granulating operation is determined in the granulating step. When the average particle diameter target value is reached, the spraying of the binder liquid is stopped and the granulation operation is stopped. ADVANTAGE OF THE INVENTION According to this invention, excessive growth or insufficient growth of a particle diameter can be prevented, and the granular material of a desired particle diameter can be obtained. The object of the present invention is achieved by means of the configuration of the invention described in each of the claims.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A method for controlling granulation of a granular material in a fluidized bed processing apparatus according to the present invention will be described below after describing the configuration and the like of a fluidized bed processing apparatus to which the present invention is applied.
Reference numeral 1 denotes a fluidized bed treatment device, which is a device having a known configuration for performing drying, granulation, coating, and the like of the granular material G. As shown in FIG. Room 4,
The filter chambers 5 are connected to each other.

The fluidized-air blowing chamber 2 is located at the lowermost part of the fluidized-bed processing device 1 and is formed of a cylindrical hollow member having an open upper surface, and a hot-air supply device or the like is appropriately connected to a side peripheral portion thereof.
The flow chamber 3 is, for example, an inverted truncated cone-shaped hollow chamber located at the upper part of the flowing air blowing chamber 2, and a bottom plate, that is, a boundary between the flowing chamber 3 and the flowing air blowing chamber 2, is provided with a perforated plate or a wire mesh. Is provided.

The spray chamber 4 is composed of a cylindrical member located above the flow chamber 3 and has a spray nozzle 6 for spraying water or a binder liquid B serving as a binder. A suitable pump 6a is provided outside the spray nozzle 6,
A valve 6b and the like are provided to enable adjustment of the spray liquid measurement or the spray air pressure of the binder liquid B or the like ejected from the spray nozzle 6. The tank 6c for the binder liquid B
A liquid level sensor or the like, or a tank 6c and a pump 6a.
By providing a flow meter in a pipe or the like connecting the fluid flow meter 6d, the amount of the binder liquid B supplied to the flow chamber 3 can be measured by these liquid meters 6d.

The filter chamber 5 is located above the spray chamber 4 and incorporates a bag filter 7 for separating the powder G from the gas, so that the powder G does not flow out of the apparatus. It is like that.

The flow chamber 3 is provided with a particle size measuring device 1.
0 is provided, and the apparatus will be described here. For example, as shown in an enlarged plan view of FIG.
A measuring head 13 serving as a sensing unit is externally attached to the main body 12, and a data processing unit 14 is further connected.

A purging nozzle is provided in the flow chamber 3 as an auxiliary member of the particle size measuring device 10 so as to face a sensing portion of the measuring head 13, or the measuring head 13 is provided.
A blow-up nozzle or the like for feeding the powder G into the container may be provided.

The measuring principle of the particle size measuring apparatus 10 will be briefly described. As shown in FIG. 2, when an appropriate amount of powdery material G as a sample is passed across the laser beam L, the laser beam generating device 12a Is partially scattered by the granular material G, and the laser light L is focused on the sensor 12c by the lens 12b. The sensor 12c converts the received laser beam L into an electric signal, amplifies the electric signal with an amplifier 14b, and converts the electric signal into an AD converter 14c.
And the computer 1 via the data transfer device 14d.
4a calculates the particle size.

The fluidized bed processing apparatus 1 to which the present invention is applied
The particle size measuring device 10 and the like provided therein are configured as described above, and the granulation control method of the present invention will be described below.

First, the particle size measuring apparatus 10 is started, and calibration is appropriately performed in a state where the powder G is not present in the trajectory of the laser beam L. Thereafter, air is sent into the fluidized chamber 3 to expand one batch of the raw material powder charged into the fluidized chamber 3 to form a fluidized bed, which is a fluidized powder layer. Thereafter, water and the binder liquid B are added to the fluidized bed from the spray nozzle 6, and the powder G is aggregated and formed. By the way, usually, in the granulation operation of adding the binder liquid B to the raw material powder to obtain the granular material G, the amount of the binder liquid B used per batch of the raw material powder to be charged into the fluidized bed processing apparatus 1 is determined by A constant amount is used according to the amount.

When the other operating conditions of the fluidized bed processing apparatus 1 except for the diameter of the spray droplets of the binder liquid B, such as the speed of the hot air and the temperature of the hot air, are constant, the diameter of the spray droplets is large. In this case, the growth speed of the particle diameter of the powder G increases, and when the spray droplet diameter is small, the growth speed of the particle diameter of the powder G decreases. The relationship between the spray droplet diameter and the particle diameter of the powder G is as follows.
It is a characteristic of the raw material powder to be handled and the fluidized bed processing apparatus 1 and also varies depending on external factors (temperature, humidity, etc.).

When the relationship between the total amount of the binder liquid used and the particle diameter of the granular material G is graphed, the relationship is almost proportional, and a straight line can be drawn. FIG. 3 shows an example of this graph. In the state where the binder liquid B has just been sprayed on the raw material powder,
The average particle diameter is not stable and a certain unmeasurable region continues.
After a while, the average particle diameter enters the measurable region in which the particle diameter at two points corresponding to the amount of the binder liquid B used is plotted. By extending the straight line connecting the two points, one batch is obtained. Of the binder liquid B when spraying the whole amount of the binder liquid B can be obtained.

The spray liquid of the binder liquid B according to the predicted average particle diameter when the predicted average particle diameter is smaller than the target average particle diameter d ₀ and when the predicted average particle diameter is larger than the target average particle diameter d _0. Control of the particle diameter of the powder G by changing the droplet diameter will be described. (1) When the predicted average particle size is smaller than the target target average particle size In FIG. 3, a straight line connecting two points to be taken when the usage amount of the binder liquid B is α and β is drawn, and this straight line is extended. When the calculated average particle diameter predicted value d ₁ is smaller than the desired average particle diameter target value d ₀ , the operating conditions (the spray droplet diameter of the binder liquid B) when the amount of the binder liquid B used is β. ), When the spraying of one batch of the binder liquid B is completed, the predicted average particle diameter d _{1 of} the obtained granular material G becomes smaller than the average particle diameter target value d ₀ with a high probability.

Therefore, when such a predicted average particle diameter d ₁ is obtained, the compressor 6e is operated by the data processing unit 14 to lower the spray air pressure as defined in claim 3 to thereby reduce the binder air pressure. The diameter of the spray droplet of the liquid B is increased. Further, as defined in claim 4, the data processing unit 1
4, one or both of the pump 6a and the valve 6b are operated to lower the spray liquid speed, thereby increasing the spray droplet diameter of the binder liquid B. When the diameter of the spray droplets of the binder liquid B is increased in this manner, the growth rate of the powder G increases, the inclination on the graph becomes sharp, and the average particle diameter prediction value can be increased.

(2) When the predicted value of the average particle size is larger than the target value of the average particle size In FIG. 3, a straight line connecting two points taken when the amount of the binder liquid B used is β and γ is drawn, and this straight line is extended. When the average particle diameter prediction value d ₂ obtained by performing the above operation is larger than the desired average particle diameter target value d ₀ , the operating conditions (the spraying of the binder liquid B (Excluding the droplet diameter), when one batch of the binder liquid B has been sprayed, the average particle diameter predicted value d _{2 of} the obtained granular material G becomes higher than the average particle diameter target value d ₀ with a high probability. I will.

Therefore, when such a predicted average particle size d ₂ is obtained, the compressor 6e is operated by the data processing unit 14 to increase the spray air pressure as defined in claim 3, thereby increasing the binder air pressure. The diameter of the spray droplet of the liquid B is reduced. Further, as defined in claim 4, the data processing unit 1
By operating one or both of the pump 6a and the valve 6b by 4 to increase the speed of the spray liquid, the spray droplet diameter of the binder liquid B is reduced. When the diameter of the spray droplets of the binder liquid B is reduced in this manner, the growth rate of the powder G decreases, the slope on the graph becomes gentle, and the average particle diameter prediction value can be reduced.

As described above, the relationship between the spray droplet size and the particle size of the granular material G is a characteristic of the raw material powder to be handled and the fluidized-bed processing apparatus 1, and therefore, when a graph is formed. It is not always straight, but may draw a curve. In such a case, if the number of measurement points is increased, the function of the curve can be derived, and the predicted average particle size can be obtained.

By the operation as described above, the binder liquid B
The granulation operation is continued by adjusting the diameter of the spray droplets, and when the measured value of the particle diameter of the powder G reaches the average particle diameter target value, the spraying of the binder liquid B is stopped to perform the granulation operation. Stop. The powder G thus granulated is finished and dried to obtain a product.

[0030]

The present invention has the above-described configuration and has the following effects. First, claim 1
According to the described invention, it is possible to appropriately correct the growth of the particle diameter of the granular material G in accordance with the predicted value of the average particle diameter at the time of spraying the whole amount of the binder liquid B, and to adjust the particle diameter at the time of spraying the whole amount of the binder liquid B. Value.

Further, according to the second aspect of the present invention, since the flowing powder G is directly measured, the set value corresponding to the state of the powder G can be changed without delay.

Further, according to the third aspect of the present invention, it is possible to change the sprayed droplet diameter to a value corresponding to the average particle diameter predicted value without delay.

Further, according to the present invention, the sprayed droplet diameter can be changed to a value corresponding to the predicted average particle diameter without delay.

Further, according to the fifth aspect of the invention, it is possible to prevent excessive growth or insufficient growth of the particle size, and to obtain a powder G having a desired particle size. By these means, at the time when the entire amount of the fixed amount of the binder liquid B used for one batch of the raw material powder is sprayed during the granulating operation of the powder G, the average particle diameter can be set to a desired value. The operation based on the organic relation between the diameter and the amount of the binder liquid used and the particle diameter can be performed, and the fluidized bed processing apparatus 1 can be automatically operated.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a fluidized bed processing apparatus and a data processing unit to which a method for controlling granulation of a granular material according to the present invention is applied.

FIG. 2 is an explanatory diagram of a measurement principle of a laser beam type particle size sensor.

FIG. 3 is a graph showing the relationship between the total amount of binder liquid used and the average particle diameter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fluidized bed processing apparatus 2 Fluidized air blowing chamber 3 Fluidized chamber 3A Perforated plate 4 Spray chamber 5 Filter chamber 6 Spray nozzle 6a Pump 6b Valve 6c Tank 6d Fluid meter 6e Compressor 7 Bag filter 10 Particle size measuring device 11 Housing 12 Main body Unit 12a Laser light generator 12b Lens 12c Sensor 13 Measurement head 14 Data processing unit 14a Computer 14b Amplifier 14c A / D converter 14d Data transfer device B Binder liquid d ₀ Average particle diameter target value d ₁ Average particle diameter prediction value d ₂ Average particle Diameter predicted value G powder L laser beam

Claims (5)

[Claims] In a fluidized bed treatment apparatus for granulating a powdery material by spraying a binder liquid onto a raw material powder flowing in a fluidized chamber, the particle size of the powdery material during a granulation operation is measured. From this measured value and the amount of the binder liquid used, when the operation of the fluidized bed processing apparatus is continued under the operating conditions at the time of the measurement, the average particle diameter at the time of spraying the entire amount of the binder liquid is predicted, and according to the predicted value. A method for controlling the granulation of a granular material in a fluidized bed processing apparatus, wherein the particle diameter of the granular material is controlled by changing the diameter of a spray droplet of a binder liquid. 2. The method for measuring the particle size of a granular material during the granulating operation,
2. The granular material in the fluidized bed processing apparatus according to claim 1, wherein a laser beam type particle size sensor is used, and the sensing unit of the laser type particle size sensor is directly made to face the granular material in the fluidized chamber. Granulation control method. 3. The change in the diameter of the sprayed droplet of the binder liquid is as follows:
3. The method for controlling granulation of a granular material in a fluidized bed processing apparatus according to claim 1, wherein the method is performed by adjusting a spray air pressure. 4. The change in the spray droplet diameter of the binder liquid is as follows:
3. The method for controlling granulation of a granular material in a fluidized bed processing apparatus according to claim 1, wherein the method is performed by adjusting a spray liquid speed. 5. When the measured value of the particle diameter of the granules during the granulation operation reaches the average particle diameter target value in the granulation step, the spraying of the binder liquid is stopped to stop the granulation operation. 5. The method for controlling granulation of a granular material in a fluidized bed processing apparatus according to claim 1, 2, 3 or 4.