JP3595949B2 - Granulation control method for granular material in fluidized bed processing equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for granulating granules using a fluidized bed treatment apparatus, and in particular, measures the particle size of the granules during a granulation operation using a laser beam particle size sensor, and uses this measured value as a basis. The present invention relates to a granulation control method for controlling the particle diameter of a granular material by predicting an average particle diameter at the time of spraying a whole amount of a binder liquid.
[0002]
BACKGROUND OF THE INVENTION
The fluidized bed granulation method using a fluidized bed treatment apparatus (fluidized bed granulation apparatus) is widely used in the food industry, the pharmaceutical industry, and the like as a method of granulating powder into fine granular particles (granules). However, since this granulation method was widely used without establishing the basic theory of granulation, such as engineering analysis of the particle growth mechanism, only the development of utilization technology according to each raw material formulation was conducted on a field-led basis. Is ahead. For this reason, both the setting of the operating conditions and the operating operation for producing the granular material having the desired physical properties (such as the average particle diameter) largely depend on the empirical skills of the operator, and automation is not promoted at present. It is.
[0003]
By the way, the material moisture in the fluidized bed is one of the operating factors that greatly affects the quality of the granular material. In recent years, a method for online measurement and control using a near infrared moisture meter has been established. , Greatly contribute to the stable production of granulated products. Various methods have been proposed for controlling the particle diameter 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, etc.” is disclosed in Japanese Patent Application Laid-Open No. 7-794, which uses a high-speed strobe device and a CCD camera to capture a still image while dispersing powder particles in a fluidized chamber with purge air. Then, based on this image, the shape, particle size, and particle size distribution of the granular material are measured, and when these values reach desired values, the operation of the apparatus is stopped.
[0005]
Japanese Patent Application Laid-Open No. 8-210962 "Image analysis method and granulation control method in a granulator" is an improvement of the invention of Japanese Patent Application Laid-Open No. 7-794, in which the dispersibility of powders and granules in a fluidized chamber is insufficient. In order to make up for the above, a method of binarizing a raw image and performing image processing of separating a particle image overlapping each other by shrinkage separation, circular separation, and wedge separation means.
In each case, together with the output of a separately provided moisture meter, measure the moisture value in the fluidized bed when the measured value reaches the desired average particle size, and continue 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 the complexity of image processing are caused.
[0006]
It has been recognized at manufacturing sites that the spray droplet size of the binder liquid sprayed into the fluidized bed is related to the particle size growth of the granular material, but the operator only uses this relationship intuitively. In fact, no technology has been developed to actively apply it to automation.
[0007]
[Technical issues to be solved]
The present invention has been made based on the recognition of such a background, and measures the particle size of the powder during the granulation operation with a laser beam particle size sensor, and based on the measured value, the spray liquid is used. The automatic operation of a fluidized bed processing apparatus that obtains a powder having a desired particle diameter by controlling the particle diameter of the powder based on the organic relationship between the droplet diameter and the amount of binder liquid used and the particle diameter. The development of a new granulation control method that makes it possible was made a technical issue.
[0008]
[Means for Solving the Problems]
In other words, the method for controlling granulation of a granular material in a fluidized bed processing apparatus according to claim 1 is a fluidized bed processing apparatus for granulating a granular material by spraying a binder liquid to a raw material powder flowing in a fluidized chamber. In the case of measuring the particle size of the granular material during the granulation operation, from the 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 measurement, the binder liquid The average particle diameter at the time of spraying the entire amount 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.
According to the present invention, it is possible to appropriately correct the growth of the particle diameter of the granular material in accordance with the predicted value of the average particle diameter at the time of spraying the entire amount of the binder liquid, and set the particle diameter at the time of spraying the entire amount of the binder liquid to a desired value. be able to.
[0009]
The granulation control method of the granular material in the fluidized bed processing apparatus according to claim 2, in addition to the above requirements, the particle size measurement of the granular material during the granulation operation, using a laser light type particle size sensor, It is characterized in that the sensing part in this laser beam type particle size sensor is directly made to 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.
[0010]
Further, in the method for controlling granulation of a granular material in the fluidized bed processing apparatus according to claim 3, in addition to the above requirements, the change of the spray droplet diameter of the binder liquid is performed by adjusting the spray air pressure. And
According to the present invention, the spray droplet diameter can be changed to a value corresponding to the predicted average particle diameter without delay.
[0011]
Furthermore, in the method for controlling granulation of a granular material in the fluidized bed processing apparatus according to claim 4, in addition to the requirements described in claim 1 or 2, the change in the spray droplet diameter of the binder liquid is controlled by changing the spray liquid velocity. The adjustment is performed by adjusting.
According to the present invention, the spray droplet diameter can be changed to a value corresponding to the predicted average particle diameter without delay.
[0012]
Furthermore, in the method for controlling granulation of a granular material in the fluidized bed processing apparatus according to claim 5, in addition to the above requirements, the measured value of the particle size of the granular material during the granulating operation is an average particle size in a granulating step. When the diameter target value is reached, the spraying of the binder liquid is stopped to stop the granulation operation.
According to the present invention, excessive growth or insufficient growth of the particle size can be prevented, and a powder having a desired particle size can be obtained.
The object of the present invention is achieved by using the configurations of the inventions described in these claims.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for controlling granulation of a granular material in a fluidized bed processing apparatus of the present invention will be described after the configuration and the like of a fluidized bed processing apparatus to which the present invention is applied are described. Reference numeral 1 denotes a fluidized bed processing apparatus, which has a known configuration for drying, granulating, coating, and the like of the granular material G. As shown in FIG. 1, a fluidized air blowing chamber 2, a fluidized chamber 3, a spray The chamber 4 and the filter chamber 5 are connected to each other.
[0014]
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 fluid chamber 3 is an inverted truncated cone-shaped hollow chamber as an example located at the upper part of the fluid wind blowing chamber 2, and a bottom plate, that is, a boundary between the fluid chamber 3 and the fluid wind blowing chamber 2, is provided with a perforated plate or a wire mesh. Is provided.
[0015]
The spray chamber 4 is formed 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. The spray nozzle 6 is provided with an appropriate pump 6a, a valve 6b, and the like on the outside so that the spray liquid can be measured or the spray air pressure of the binder liquid B or the like ejected from the spray nozzle 6 can be adjusted. The tank 6c for the binder liquid B is provided with a liquid level sensor or the like, or a pipe or the like connecting the tank 6c and the pump 6a is provided with a flow meter. Measurement of the amount of the binder liquid B is performed.
[0016]
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. is there.
[0017]
A particle size measuring device 10 is provided for the flow chamber 3, and this device will be described here. As an example, as shown in an enlarged plan view in FIG. 1, a portion surrounded by a housing 11 is a main body 12, and a measuring head 13 serving as a sensing unit is externally attached to the main body 12. Further, a data processing unit 14 is connected.
[0018]
In addition, 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 the sensing part of the measuring head 13, or a blow-up nozzle or the like for feeding the powder G into the measuring head 13 is provided. It may be.
[0019]
Here, the measurement principle of the particle size measuring device 10 will be briefly described. As shown in FIG. 2, when an appropriate amount of powder G, which is a sample, is passed across the laser beam L, the particle is emitted from the laser beam generating device 12a. A part of the laser light L is 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 calculates a particle diameter by a computer 14a via an AD converter 14c and a data transfer device 14d.
[0020]
The fluidized bed processing apparatus 1 to which the present invention is applied and the particle size measuring apparatus 10 and the like provided therein are configured as described above, and the granulation control method of the present invention will be described below.
[0021]
First, the particle size measuring device 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 as 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 one batch of the raw material powder to be charged into the fluidized bed processing apparatus 1 is determined as follows: A constant amount is used according to the amount.
[0022]
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 hot air velocity and the hot air temperature, are constant, if the diameter of the spray droplets is large, The growth rate of the particle diameter of the body G increases, and the growth rate of the particle diameter of the granular material G decreases when the spray droplet diameter is small. The relationship between the sprayed droplet diameter and the particle diameter of the granular material G is a characteristic of the raw material powder to be handled and the fluidized bed processing apparatus 1, and also differs depending on external factors (temperature, humidity, etc.). come.
[0023]
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 substantially proportional, and a straight line can be drawn. FIG. 3 shows an example of this graph. In a state where the binder liquid B has just started to be sprayed on the raw material powder, the average particle diameter is not stabilized, and a certain unmeasurable region continues. After a while, the average particle diameter enters the measurable region where it is stable. When plotting the particle diameters at two points corresponding to the usage amount of the binder liquid B, by extending the straight line connecting these two points, one batch can be obtained. Of the binder liquid B when spraying the entire amount of the binder liquid B can be obtained.
[0024]
Hereinafter, when the average particle diameter predicted value is smaller than the average particle diameter target value d ₀ and when the average particle diameter target value d ₀ is larger, the spray droplet diameter of the binder liquid B according to the average particle diameter predicted value is calculated as follows. The control of the particle size of the granular material G by changing it will be described.
(1) When the predicted average particle diameter is smaller than the target average particle diameter 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. If 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. in the excluded) and finishes spraying a binder solution B one batch, the average particle size predicted value d ₁ of the resulting particulate material G becomes smaller than the average particle diameter target value d ₀ with high probability.
[0025]
Therefore if such an average particle diameter of the predicted value d ₁ is obtained, as defined in claim 3, by operating the compressor 6e by the data processing unit 14, by reducing the atomizing air pressure, the binder solution B Increase the spray droplet diameter.
Further, as defined in claim 4, one or both of the pump 6a and the valve 6b are operated by the data processing unit 14 to decrease the spray liquid speed, thereby increasing the spray droplet diameter of the binder liquid B.
When the diameter of the spray droplet 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.
[0026]
(2) When the predicted average particle size is larger 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 β and γ is drawn, and this straight line is extended. the average particle size predicted value d ₂ thus determined desired if the average is larger than the particle size desired value d ₀ is spray droplet diameter of the binder solution operating conditions (binder solution B at the time of usage γ of B in the excluded) and finishes spraying a binder solution B one batch, the average particle size predicted value d ₂ of the resulting particulate material G becomes larger than the average particle diameter target value d ₀ with high probability.
[0027]
Therefore if such an average particle size predicted value d ₂ is obtained, as defined in claim 3, by operating the compressor 6e by the data processing unit 14, increasing the atomizing air pressure, the binder solution B Reduce the spray droplet size.
As defined in claim 4, one or both of the pump 6a and the valve 6b are operated by the data processing unit 14 to increase the speed of the spray liquid, thereby reducing the diameter of the spray liquid droplets of the binder liquid B.
When the diameter of the spray droplets of the binder liquid B is reduced in this manner, the growth speed of the granular material G decreases, the slope on the graph becomes gentle, and the average particle diameter predicted value can be reduced.
[0028]
As described above, since the relationship between the diameter of the spray droplet and the particle size of the granular material G is a characteristic of the raw material powder to be handled and the characteristic of the fluidized bed processing apparatus 1, it is not necessarily a straight line when graphed. It is not always the case and sometimes draws a curve. In such a case, the function of the curve can be derived by increasing the number of measurement points, and the predicted value of the average particle diameter can be obtained.
[0029]
By the above operation, the spray droplet diameter of the binder liquid B is adjusted and the granulation operation is continued. When the measured value of the particle diameter of the powder G reaches the average particle diameter target value, the binder liquid B Is stopped to stop the granulation operation. The granules G thus granulated are finished and dried to obtain a product.
[0030]
【The invention's effect】
The present invention has the configuration described above, and has the following effects.
First, according to the first aspect of the present invention, it is possible to appropriately correct the growth of the particle diameter of the granular material G according to the predicted value of the average particle diameter at the time of spraying the entire amount of the binder liquid B. The particle size can be a desired value.
[0031]
According to the second aspect of the present invention, since the flowing granular material G is directly measured, the set value corresponding to the state of the granular material G can be changed without delay.
[0032]
Furthermore, according to the third aspect of the present invention, the spray droplet diameter can be changed to a value corresponding to the predicted average particle diameter without delay.
[0033]
Furthermore, according to the fourth aspect of the invention, it is possible to change the spray droplet diameter to a value corresponding to the predicted average particle diameter without delay.
[0034]
Furthermore, according to the fifth aspect of the present invention, it is possible to prevent excessive growth or insufficient growth of the particle size, and to obtain the powder G having a desired particle size.
By these means, at the time of spraying the entire amount of the fixed amount of the binder liquid B used for one batch of the raw material powder at the time of the granulating operation of the granular material G, the average particle diameter can be set to a desired value. The operation based on the organic relationship 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 Spraying chamber 5 Filter chamber 6 Spraying nozzle 6a Pump 6b Valve 6c Tank 6d Liquid level 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 unit 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 light

Claims (5)

In a fluidized bed processing apparatus that granulates granules by spraying a binder liquid on the raw material powder flowing in the fluidized chamber, the particle size of the granules during the granulation operation is measured, and this measured value and When the operation of the fluidized bed processing apparatus is continued under the operating conditions at the time of measurement from the amount of the binder liquid used, the average particle diameter at the time of spraying the entire amount of the binder liquid is predicted, and the spraying of the binder liquid is performed according to the predicted value. A granulation control method for a granular material in a fluidized bed processing apparatus, characterized in that the particle diameter of the granular material is controlled by changing a droplet diameter. The particle size measurement of the granules during the granulation operation is performed by using a laser beam type particle size sensor and directing a sensing unit in the laser beam type particle size sensor directly to the granules in the fluidized chamber. A method for controlling granulation of a granular material in the fluidized bed processing apparatus according to claim 1. 3. The method according to claim 1, wherein the change in the spray droplet diameter of the binder liquid is performed by adjusting a spray air pressure. The method according to claim 1 or 2, wherein the change in the diameter of the spray droplets of the binder liquid is performed by adjusting the velocity of the spray liquid. When the measured value of the particle size of the granules during the granulation operation reaches the average particle size target value in the granulation step, the spraying of the binder liquid is stopped and the granulation operation is stopped. 5. The method for controlling granulation of a granular material in the fluidized bed processing apparatus according to claim 1, 2, 3 or 4.

Images