JP4584560B2 - Grinding equipment and method and fluidized bed classifier - Google Patents

Description

  The present invention relates to a pulverizing equipment and a pulverizing method for pulverizing raw materials, and a fluidized bed type classifier that can be used in these.

  As a first conventional technique, a pulverizer in which a fluidized bed type classifier is installed in a roller mill, a tube mill, and a raw material conveyance path from the roller mill to the tube mill is known. In this pulverizer, the powdered raw material is pre-ground by a roller mill and sent to a fluidized bed classifier, classified by this fluidized bed type classifier, and the fine powder is supplied to a tube mill. The remaining portion including the minute is returned to the roller mill. The fluidized bed classifier divides the inside of the hollow container with a porous plate, the fluidized bed chamber is provided on the porous plate, the inlet and the air outlet for the powdered raw material are provided, and the air inlet chamber is provided below the porous plate. An air inlet is provided. In addition, the fluidized bed classifier is provided with an upper chute that overflows and discharges the fluidized fine powder of the granular material at a position away from the porous plate in the fluidized bed chamber, and deposits on the porous plate. The lower chute which discharges | emits simultaneously the coarse powder and the fine powder which exists in the vicinity is provided. In this pulverizing apparatus, the coarse powder and the fine powder are returned to the roller mill, so that the vibration during the pulverization in the roller mill is suppressed and the pulverization efficiency is increased by the action of the fine powder (see, for example, Patent Document 1).

  As a second prior art, a fluidized bed classifier similar to the fluidized bed classifier of the first prior art is known. In this fluidized bed type classifier, the dispersion plate corresponding to the porous plate of the first prior art has a slope that decreases toward the inside of the hollow container, and the first prior art is at the lowest position of the dispersion plate. A coarse powder discharge chute corresponding to the lower chute is provided, and a fine powder discharge chute corresponding to the upper chute of the first prior art is provided on the side wall of the hollow container (see, for example, Patent Document 2).

  As a third conventional technique, a fluidized bed classifier for classifying coal or the like is known. In this fluidized bed type classifier, a granular processed material such as coal is classified using a fluidized bed while drying the processed material (see, for example, Patent Document 3).

Japanese Patent No. 2579885 Japanese Patent No. 2812917 Japanese Patent No. 2840579

  In the fluidized bed classifier of the first prior art, an upper chute is provided at a position away from the perforated plate of the fluidized bed chamber, and the fine powder content is overflowed and discharged, so the following two problems Have

  The first problem is that the pulverization efficiency slightly decreases. For example, when the granular material to be pulverized by the roller mill becomes coarse, the granular material supplied to the fluidized bed classifier from the roller mill becomes coarse. In such a case, a small amount of coarse powder is mixed into the fine powder and supplied to the tube mill. When a coarse powder is supplied to the tube mill, a ball having a large outer diameter must be used as a grinding medium in order to pulverize the coarse powder, compared to a case where only the fine powder is pulverized. However, when a ball having a large outer diameter is used, the pulverization efficiency is lowered due to a reduction in the contact area between the ball and the granular material. Therefore, the grinding efficiency in the tube mill is reduced.

  The second problem is that it is difficult to change the particle size of the fine powder. If it is necessary to change the particle size of the fine powder supplied to the tube mill due to changes in the type of cement product to be obtained using a pulverizer, the flow rate of air introduced into the fluidized bed classifier is changed. Although the particle size can be changed, it is difficult to maintain the classification accuracy because the fluidized state of the granular material is deteriorated by the influence of the change in the air flow rate. Therefore, in order to maintain the classification accuracy, it is difficult to change the particle size of the fine powder.

  The second prior art uses a dispersion plate that becomes lower inward, provides a coarse powder discharge chute at its lowest position, and provides a fine powder discharge chute on the side wall of the hollow container to improve classification accuracy. However, the two problems of the first prior art cannot be completely solved and have the same problems.

  The third prior art fluidized bed classifier is a fluidized bed classifier used for drying and classification of coal and the like, and is used for the pulverizer as described in the first prior art. If applied as it is, the pulverizing apparatus becomes large in size, resulting in high costs and energy consumption. Therefore, it cannot be applied to the pulverizer as it is, and some improvement is required.

  An object of the present invention is a pulverization facility provided with a fluidized bed type classification device between a coarse pulverization device and a fine pulverization device, and is capable of returning coarse powder and fine powder to the coarse pulverization device. An object of the present invention is to provide a pulverization facility and method capable of obtaining high pulverization efficiency by improving the classification accuracy of a fluidized bed classifier while maintaining the advantages of the apparatus, and a classifier that can be used for this.

The present invention includes a coarse pulverization apparatus for pulverizing raw materials,
A fine pulverizer for further pulverizing the raw material crushed by the coarse pulverizer;
A pulverization facility including a fluidized bed classifier provided between a coarse pulverizer and a fine pulverizer;
Fluidized bed classifier
A hollow container,
A plurality of through holes are formed, the container is partitioned vertically, and includes a partition member that forms an upper fluidized bed chamber and a lower gas introduction chamber,
A gas introduction port that is open to the gas introduction chamber and is supplied with a fluidizing gas that is ejected from the gas introduction chamber to the fluidized bed chamber through each through hole of the partition member;
An inlet to the fluidized bed chamber, to which raw materials crushed by a coarse pulverizer are supplied;
A fine powder discharge port that opens to the upper layer region in the fluidized bed chamber and is connected to the fine pulverization apparatus to convey and discharge the fine powder component to the fluidizing gas;
Open to the lower layer region in the fluidized bed chamber and connected to the coarse pulverization apparatus, and a coarse powder outlet for discharging the coarse powder component and the fine powder component is formed,
A classifier discharge feeder that discharges the coarse powder component and fine powder component discharged through the coarse powder discharge port;
A wind box pressure sensor for detecting the pressure of the fluidizing gas in the gas introduction chamber;
A fluidized bed chamber sensor for detecting the pressure of the fluidizing gas in the fluidized bed chamber;
Based on the detection results of the wind box pressure sensor and the fluidized bed chamber sensor, the classifier discharge feeder is set so that the detected differential pressure between the pressure in the gas introduction chamber and the pressure in the fluidized bed chamber becomes a preset differential pressure. A control circuit that controls and maintains a constant bed thickness of the fluidized bed ,
In the control circuit, the flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the coarse powder component is fluidized to form a fluidized bed. the speed or more and the fluidized bed such that the speed less than that bubbles are generated that a milling equipment which is characterized that you control the classifier discharge feeder.

  According to the present invention, the raw material is first supplied to the coarse pulverizer and pulverized, and the pulverized raw material is supplied to the classifier. In a fluidized bed classifier, a hollow container is partitioned by a partition member, and a fluidized bed chamber and a gas introduction chamber are formed. The raw material is supplied to the fluidized bed chamber, and the fluidizing gas is supplied to the gas introduction chamber. The fluidizing gas supplied to the gas introduction chamber is ejected from the through hole of the partition member into the fluidized bed chamber, the raw material on the partition member is fluidized to form the fluidized bed portion, and the fluidized bed portion. A free board portion is formed above. The coarse powder component having a large particle size stays on the partition member, and the fine powder component having a small particle size is blown upward. At this time, the coarse powder component and the fine powder component are not completely separated, but a part of the fine powder component stays on the partition member together with the coarse powder component. The coarse powder component and fine powder component staying on the partition member are discharged from the lower layer region of the fluidized bed chamber, returned to the coarse pulverizer, and pulverized again. The fine powder component blown up is conveyed to the fluidizing gas, discharged from the upper layer region of the fluidized bed chamber, and supplied to the fine pulverizer. The fine powder component supplied to the fine pulverizer is further finely pulverized by the fine pulverizer to produce a product.

  By providing the fluidized bed classifier in the pulverization facility, part of the fine powder component is returned to the coarse pulverizer together with the coarse powder component. When the coarse powder component and the fine powder component are mixed, the fine powder component particles enter between the coarse powder component particles and the porosity decreases, so that the displacement of the grinding media such as the rollers becomes small during crushing in the coarse grinding device. The vibration level decreases. When the vibration is lowered, the reduction force of the grinding medium in the coarse pulverizing apparatus can be maximized, so that the pulverization efficiency in the coarse pulverizing apparatus is improved.

  Furthermore, in the fluidized bed type classifier, the fine powder component to be supplied to the fine pulverizer is discharged by gas conveyance. In the configuration of overflowing to the chute as in the prior art, since the particle size of the blown up component cannot be adjusted between the partition member and the chute, when the particle size of the raw material supplied to the coarse pulverizer becomes large, In addition, when the flow rate of the fluidized gas is changed to change the product type, the coarse powder component may be mixed with the fine powder component. On the other hand, as in the present invention, in the configuration of discharging by gas conveyance, the particle size of the blown-up component is adjusted in the free board portion, and the coarse powder component in the above-mentioned case that could not be solved by the conventional technology Splashing is prevented, and only the fine powder component is reliably discharged from the fine powder discharge port and supplied to the fine grinding device. Therefore, compared with the case where it is necessary to consider that the coarse powder component is mixed, a pulverization medium suitable for pulverization of the fine powder component can be selected, and the pulverization efficiency of the fine pulverization apparatus can be increased.

Thus, by improving the configuration for discharging the fine powder component in the fluidized bed classifier, the fine powder component can be returned to the coarse pulverizer together with the coarse powder component. The advantages can be maintained as they are, and further, the coarse powder component can be prevented from being sprinkled into the pulverizing apparatus. Therefore, it is possible to maintain the advantage of improving the pulverization efficiency in the coarse pulverizer as it is, further improve the pulverization efficiency of the fine pulverizer, and improve the pulverization efficiency of the entire pulverization equipment.
Further, in the fluidized bed type classifier, the fluidized gas flow rate can be kept constant by keeping the fluidized bed thickness constant and keeping the differential pressure constant. Thereby, the classification particle size can be kept constant and high classification accuracy can be secured.
Further, the flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the fluidized bed has a speed higher than the speed at which the coarse powder component is fluidized to form a fluidized bed. By controlling the classifier discharge feeder so as to be less than the speed at which bubbles are generated inside, not only fine powder components can be discharged by gas conveyance, but also the fluidized state of the fluidized bed formed on the partition member However, it becomes a uniform fluidized state or a state very close to this, and a stable and good fluidized state can be obtained.
Moreover, if such a good flow state can be formed, a raw material inlet is formed at one place of the container and a coarse powder outlet is formed at one place of the container. Even if it does not have a complicated configuration that forms the coarse powder outlets uniformly dispersed, and without taking any measures such as inclining the partition member, it has a substantially uniform layer thickness over the entire region on the partition member. A fluidized bed can be formed, the classification flow rate can be uniform, and high classification accuracy can be obtained.

Further, the present invention provides a fluidized bed type classifier for classifying the raw material pulverized by the coarse pulverizer between the coarse pulverizer for pulverizing the raw material and the fine pulverizer for further pulverizing the raw material pulverized by the coarse pulverizer. Provided,
In the fluidized bed type classifier,
A hollow container is divided up and down by a partition member having a plurality of through holes, and an upper fluidized bed chamber and a lower gas introduction chamber are formed,
While introducing the raw material into the fluidized bed chamber, the fluidizing gas is introduced into the gas introducing chamber and ejected into the fluidized bed chamber through each through hole of the partition member,
The fine powder component is transported and discharged from the upper layer region of the fluidized bed chamber to the fluidizing gas, and supplied to the fine grinding device.
The coarse powder component and the fine powder component are discharged from the lower layer region of the fluidized bed chamber by the classifier discharge feeder, and supplied to the coarse pulverizer.
Detecting the pressure of the fluidizing gas in the gas introduction chamber by a windbox pressure sensor;
Detecting the pressure of the fluidizing gas in the fluidized bed chamber by a fluidized bed chamber sensor;
Based on the detection results of the wind box pressure sensor and the fluidized bed chamber sensor, the classifier discharge feeder is set so that the detected differential pressure between the pressure in the gas introduction chamber and the pressure in the fluidized bed chamber becomes a preset differential pressure. Control and keep the fluidized bed thickness constant ,
The flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the fluid velocity is higher than the speed at which the coarse powder component is fluidized to form a fluidized bed. such that the speed less than that bubbles are generated in the layer, a grinding method which is characterized that you control the classifier discharge feeder.

  According to the present invention, the raw material is first pulverized by a coarse pulverizer, and the pulverized raw material is supplied to a classifier. In the classifying device, a hollow container is partitioned by a partition member to form a fluidized bed chamber and a gas introduction chamber. The raw material is supplied to the fluidized bed chamber, and the fluidizing gas is supplied to the gas introduction chamber. The fluidizing gas supplied to the gas introduction chamber is ejected from the through hole of the partition member into the fluidized bed chamber, fluidizing the raw material on the partition member to form a fluidized bed portion, and free above the fluidized bed portion. A board part is formed. The coarse powder component having a large particle size stays on the partition member, and the fine powder component having a small particle size is blown upward. At this time, the coarse powder component and the fine powder component are not completely separated, but a part of the fine powder component stays on the partition member together with the coarse powder component. The coarse powder component and fine powder component staying on the partition member are discharged from the lower layer region of the fluidized bed chamber, returned to the coarse pulverizer, and pulverized again. Moreover, the fine powder component blown up is conveyed to the fluidizing gas, discharged from the upper layer region of the fluidized bed chamber, and supplied to the fine grinding device. The fine powder component supplied to the fine pulverizer is further finely pulverized by the fine pulverizer to produce a product.

  By providing the fluidized bed classifier in the pulverization facility, some fine powder is returned to the coarse pulverizer together with the coarse powder. When the coarse powder component and the fine powder component are mixed, the fine powder component particles enter between the coarse powder component particles and the porosity decreases, so that the displacement of the grinding media such as the rollers becomes small during crushing in the coarse grinding device. The vibration level decreases. When the vibration becomes low, the rolling force of the pulverizing medium in the coarse pulverization apparatus can be maximized, so that the pulverization efficiency in the coarse pulverization apparatus can be improved. Further, the fluidized bed classifier discharges the fine powder component to be supplied to the fine pulverizer by gas conveyance. In the configuration of overflowing to the chute as in the prior art, since the particle size of the blown up component cannot be adjusted between the partition member and the chute, when the particle size of the raw material supplied to the coarse pulverizer becomes large, In addition, when the flow rate of the fluidized gas is changed to change the product type, the coarse powder component may be mixed with the fine powder component. On the other hand, as in the present invention, by adopting a configuration that discharges by gas conveyance, the particle size of the blown-up component is adjusted in the free board portion, and the coarseness in the above-described case that could not be solved by the conventional technology. It is possible to prevent confusion of the powder component, and to reliably discharge only the fine powder component from the fine powder discharge port and supply it to the fine grinding device. Therefore, compared with the case where it is necessary to consider that the coarse powder component is mixed, a pulverization medium suitable for pulverization of the fine powder component can be selected, and the pulverization efficiency of the fine pulverization apparatus can be increased.

Thus, by improving the configuration for discharging the fine powder component in the fluidized bed classifier, the fine powder component can be returned to the coarse pulverizer together with the coarse powder component. The advantages can be maintained as they are, and further, the coarse powder component can be prevented from being sprinkled into the pulverizing apparatus. Therefore, it is possible to maintain the advantage of improving the pulverization efficiency in the coarse pulverizer as it is, further improve the pulverization efficiency of the fine pulverizer, and improve the pulverization efficiency of the entire pulverization equipment.
Further, in the fluidized bed type classifier, the fluidized gas flow rate can be kept constant by keeping the fluidized bed thickness constant and keeping the differential pressure constant. Thereby, the classification particle size can be kept constant and high classification accuracy can be secured.
In addition, the flow rate of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the fluidized bed is equal to or higher than the speed at which the coarse powder component is fluidized to form a fluidized bed. By controlling the classifier discharge feeder so as to be less than the speed at which bubbles are generated inside, not only fine powder components can be discharged by gas conveyance, but also the fluidized state of the fluidized bed formed on the partition member However, it becomes a uniform fluidized state or a state very close to this, and a stable and good fluidized state can be obtained.
Moreover, if such a good flow state can be formed, a raw material inlet is formed at one place of the container and a coarse powder outlet is formed at one place of the container. Even if it does not have a complicated configuration that forms the coarse powder outlets uniformly dispersed, and without taking any measures such as inclining the partition member, it has a substantially uniform layer thickness over the entire region on the partition member. A fluidized bed can be formed, the classification flow rate can be uniform, and high classification accuracy can be obtained.

The present invention also includes a hollow container,
A plurality of through holes are formed, partition the container up and down, and a partition member that forms an upper fluidized bed chamber and a lower gas introduction chamber;
Centrifuge means provided in the fluidized bed chamber,
The container
A gas introduction port that is open to the gas introduction chamber and is supplied with a fluidizing gas that is ejected from the gas introduction chamber to the fluidized bed chamber through each through hole of the partition member;
An inlet to the fluidized bed chamber for supplying raw materials;
A coarse powder outlet opening in the lower layer region in the fluidized bed chamber and discharging the coarse powder component and the fine powder component;
A gas outlet opening in the upper layer region in the fluidized bed chamber is formed,
The centrifuge means
A cone provided to cover the gas outlet, and a solid outlet for discharging fine powder at the lower end is formed;
An introduction passage is formed that opens to the upper layer region of the fluidized bed chamber, conveys the fine powder component to the fluidizing gas and introduces it into the cone, and a flow path changing piece for changing the flow passage cross-sectional area of the introduction passage. A fine powder introduction section,
A classifier discharge feeder that discharges the coarse powder component and fine powder component discharged through the coarse powder discharge port;
A wind box pressure sensor for detecting the pressure of the fluidizing gas in the gas introduction chamber;
A fluidized bed chamber sensor for detecting the pressure of the fluidizing gas in the fluidized bed chamber;
Based on the detection results of the wind box pressure sensor and the fluidized bed chamber sensor, the classifier discharge feeder is set so that the detected differential pressure between the pressure in the gas introduction chamber and the pressure in the fluidized bed chamber becomes a preset differential pressure. controlled, have a control circuit for holding the thickness of the fluidized bed constant,
In the control circuit, the flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the coarse powder component is fluidized to form a fluidized bed. The fluidized bed classifier is characterized in that the classifier discharge feeder is controlled so as to be equal to or higher than a predetermined speed and lower than a speed at which bubbles are generated in the fluidized bed.

  According to the present invention, the hollow container is partitioned by the partition member, and the fluidized bed chamber and the gas introduction chamber are formed. The fluidized bed chamber is supplied with the raw material from the inlet, and the gas introducing chamber is supplied with the fluidizing gas from the gas inlet. The fluidizing gas supplied to the gas introduction chamber passes through the through holes formed in the partition member and is ejected to the fluidized bed chamber, and the raw material on the partition member charged into the fluidized bed chamber is fluidized and fluidized. A layer portion is formed, and a free board portion is formed above the fluidized bed portion. The coarse powder component having a large particle size stays on the partition member, and the fine powder component having a small particle size is blown upward. The coarse powder component and the fine powder component are not completely separated, but a part of the fine powder component stays on the partition member together with the coarse powder component.

  The fluidized bed chamber is provided with a centrifugal separator. In the centrifugal separation means, the fine powder component is transported to the fluidizing gas from the upper layer region of the fluidized bed chamber and introduced into the cone, and the centrifugal force is used in the cone to convert the fluidized gas and the fine powder component. To be separated. The fluidizing gas is discharged from the gas outlet, and the fine powder component is discharged from the solid outlet. Thus, the fine powder component is introduced into the centrifugal separation means by gas conveyance. In the configuration in which the chute overflows as in the prior art, the particle size of the blown-up component cannot be adjusted between the partition member and the chute, and the coarse powder component may be mixed with the fine powder component. On the other hand, as in the present invention, by adopting a configuration in which the centrifugal separation means is introduced by gas conveyance, the particle size of the blown-up component is adjusted at the free board portion, and only the fine powder component is reliably guided into the cone. . Thus, only the fine powder component can be discharged from the solid discharge port with high classification accuracy.

Furthermore, the introduction passage for introducing the mixed fluid of the fine powder component and the fluidizing gas into the centrifugal separation means can change the flow passage cross-sectional area by the flow passage changing piece. By changing the cross-sectional area of the flow path, it is possible to adjust the particle size of the fine powder component discharged together with the fluidized gas from the gas discharge port.
Further, the flow rate of the fluidizing gas can be kept constant by keeping the layer thickness of the fluidized bed constant in the container and keeping the differential pressure constant. Thereby, the classification particle size can be kept constant and high classification accuracy can be secured.
In addition, the flow rate of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the fluidized bed is equal to or higher than the speed at which the coarse powder component is fluidized to form a fluidized bed. By controlling the classifier discharge feeder so as to be less than the speed at which bubbles are generated inside, not only fine powder components can be discharged by gas conveyance, but also the fluidized state of the fluidized bed formed on the partition member However, it becomes a uniform fluidized state or a state very close to this, and a stable and good fluidized state can be obtained.
Moreover, if such a good flow state can be formed, a raw material inlet is formed at one place of the container and a coarse powder outlet is formed at one place of the container. Even if it does not have a complicated configuration that forms the coarse powder outlets uniformly dispersed, and without taking any measures such as inclining the partition member, it has a substantially uniform layer thickness over the entire region on the partition member. A fluidized bed can be formed, the classification flow rate can be uniform, and high classification accuracy can be obtained.

  According to the first and second aspects of the present invention, the raw material pulverized by the coarse pulverizer is classified, and the coarse powder component is returned to the coarse pulverizer and pulverized again. The coarse powder that could not be made can be pulverized again into a fine powder. Furthermore, not only the coarse powder component but also the fine powder component are returned to the coarse pulverizer. When the coarse powder component and the fine powder component are mixed, the fine powder component particles enter between the coarse powder components and the porosity decreases, so that the roller displacement is reduced during crushing in the coarse pulverizer and the vibration level is lowered. To do. When the vibration is reduced, the rolling force in the coarse pulverizing apparatus can be maximized, so that the pulverization efficiency in the coarse pulverizing apparatus can be increased. Further, in the fluidized bed classifier, the fine powder component is discharged by gas conveyance, so that the coarse powder component is prevented from being discharged from the fine powder discharge port, and only the fine powder component can be discharged from the fine powder discharge port. Since high classification accuracy can be obtained in this way, the pulverization apparatus can be configured to pulverize only the fine powder component, and a pulverization facility that can achieve high pulverization efficiency can be realized.

Thus, by improving the configuration for discharging the fine powder component in the fluidized bed classifier, the fine powder component can be returned to the coarse pulverizer together with the coarse powder component. The advantages can be maintained as they are, and further, the coarse powder component can be prevented from being sprinkled into the pulverizing apparatus. Therefore, it is possible to maintain the advantage of improving the pulverization efficiency in the coarse pulverizer as it is, further improve the pulverization efficiency of the fine pulverizer, and improve the pulverization efficiency of the entire pulverization equipment.
Further, in the fluidized bed type classifier, the fluidized gas flow rate can be kept constant by keeping the fluidized bed thickness constant and keeping the differential pressure constant. Thereby, the classification particle size can be kept constant and high classification accuracy can be secured.
In addition, in the fluidized bed classifier, not only fine powder components can be discharged by gas conveyance, but the fluidized state of the fluidized bed formed on the partition member becomes a uniform fluidized state or a state very close to this, and is stable. A good flow state can be obtained.
Moreover, if such a good flow state can be formed, a fluidized layer having a substantially uniform layer thickness can be formed over the entire region on the partition member with a simple configuration, and the classification flow rate becomes a uniform flow rate, High classification accuracy can be obtained.

  According to the third aspect of the present invention, in the fluidized bed type classifier, the advantage achieved in the fluidized bed type classifier of the prior art that the fine powder component can be discharged from the coarse powder outlet together with the coarse powder component is maintained as it is. Furthermore, it is possible to prevent the coarse powder component from being confounded and to discharge only the fine powder component from the solid outlet of the centrifugal separator. Further, since the centrifugal separation means is integrated, the fine powder component can be discharged from the fluidized bed classifier separately from the gas without providing a separate separation means. Further, by integrating the separating means, the entire apparatus can be made compact and the equipment cost can be reduced. In addition, when the separation means is provided separately, wasteful energy consumption due to pressure loss between the fluidized bed classifier and the separation means occurs, but this wasteful energy consumption is suppressed by integrating, Energy saving can be achieved.

In addition, since the particle size of the fine powder component introduced into the cone of the separation means can be adjusted, the fine powder that gets mixed into the gas when the mixed fluid introduced into the cone is separated into the gas and the fine powder component. It is possible to make the components so granular that they can be directly used as a product. Therefore, by using this fluidized bed type classifier installed between the coarse pulverizer and the fine pulverizer, the fine powder components that are trapped in the gas discharged from the fluidized bed classifier can be collected and used as it is. It can be made into a product, and can be prevented from being excessively pulverized by being supplied to a fine pulverizer and pulverized, thereby further increasing the pulverization efficiency.
Further, the flow rate of the fluidizing gas can be kept constant by keeping the layer thickness of the fluidized bed constant in the container and keeping the differential pressure constant. Thereby, the classification particle size can be kept constant and high classification accuracy can be secured.
Moreover, not only the fine powder component can be discharged by gas conveyance in the container, but also the fluidized state of the fluidized bed formed on the partition member becomes a uniform fluidized state or a state very close to this, and a stable and good flow The state can be obtained.
Moreover, if such a good flow state can be formed, a fluidized layer having a substantially uniform layer thickness can be formed over the entire region on the partition member with a simple configuration, and the classification flow rate becomes a uniform flow rate, High classification accuracy can be obtained.

  FIG. 1 is a cross-sectional view showing a fluidized bed classifier 1 according to an embodiment of the present invention. FIG. 2 is a system diagram showing a pulverization facility 30 including the fluidized bed classifier 1. The pulverization facility 30 includes a roller mill 31 as a coarse pulverizer, a tube mill 32 as a fine pulverizer, and a fluidized bed classifier 1 interposed between the roller mill 31 and the tube mill 32. This is equipment for pulverizing the raw material with a roller mill 31 and a tube mill 32 to obtain a fine powder product. In the present embodiment, for example, cement clinker is pulverized as a raw material and used as equipment for obtaining a cement product as a product.

  The fluidized bed type classifier 1 which is a fluidized bed type classifier provided in the pulverizing equipment 30 is configured to supply raw materials into a coarse powder component composed of coarse powder having a large particle size and a fine powder component composed of fine powder having a small particle size. This is a classification device. The coarse powder component is a component having a particle size greater than or equal to a predetermined classified particle size, and the fine powder component is a component having a particle size less than the classified particle size.

  The fluidized bed classifier 1 includes a hollow container 2 and a partition member 3 that partitions the container 2. The container 2 is formed by closing both end portions of the cylindrical peripheral wall portion 4 with flat end wall portions 5 and 6. The peripheral wall portion 4 has a substantially cylindrical substantially cylindrical portion 7 and a truncated cone-shaped truncated cone portion 8 that is connected to the substantially cylindrical portion 7 and has a diameter reduced as the distance from the substantially cylindrical portion 7 increases. The container 2 is provided with the axis substantially vertical so that the substantially cylindrical portion 7 is disposed on the upper side.

  The partition member 3 is a so-called dispersion plate and is a disk-shaped member, and is provided in the vicinity of a boundary portion where the substantially cylindrical portion 7 and the truncated cone portion 8 in the container 2 are continuous. The partition member 3 is provided with a peripheral edge portion connected to the inner surface portion of the container 2, and partitions the container 2 in the vertical direction. The container 2 is divided into an upper fluidized bed chamber 10 and a lower gas introduction chamber 11. And form. The portion where the gas introduction chamber 11 is formed is called a wind box or the like. A plurality of through holes 13 penetrating in the thickness direction are formed in the partition member 3, and the fluidized bed chamber 10 and the gas introduction chamber 11 communicate with each other through these through holes 13.

  In the container 2, a gas introduction port 15 that opens to the gas introduction chamber 11 is formed, and an introduction tube 16 that connects the gas introduction port 15 with a space in the tube is provided. As indicated by an arrow A, the gas introduction port 15 is supplied with a fluidizing gas, whereby the fluidizing gas is introduced into the gas introduction chamber 11. When the fluidizing gas is introduced into the gas introduction chamber 11, as indicated by an arrow B, the fluidizing gas is ejected from the gas introduction chamber into the fluidized bed chamber 10 through the through holes 13 of the partition member 3. In the present embodiment, the fluidizing gas is air, which is specifically cold air, but may be hot air. Hereinafter, this fluidizing gas is referred to as classified air.

  In addition, the container 2 is provided with an input port 17 that opens into the fluidized bed chamber 10, and a raw material input tube 18 that is connected to the space in the tube at the input port 17. The raw material is supplied to the inlet 17 as indicated by an arrow C, and the raw material is supplied to the fluidized bed chamber 10 by this. Since the classification air is ejected from the gas introduction chamber 11 through the through holes 13 into the fluidized bed chamber 10, the raw material introduced into the fluidized bed chamber 10 is subjected to the action of being blown upward by the classified air. Thus, a fluidized bed is formed. The fluidized bed is formed in the lower layer region 10a of the fluidized bed chamber 10, and this region becomes the fluidized bed portion, and the upper portion thereof becomes the free board portion.

  The raw material charged into the fluidized bed classifier 1 includes a coarse powder component and a fine powder component. The coarse powder component is a component composed of coarse powder having a particle size equal to or higher than a predetermined classified particle size, and the fine powder component is a component composed of fine powder having a particle size less than the classified particle size. When classification air is blown into such a raw material, the coarse powder component stays while flowing on the partition member 3 without being blown upward, forms a fluidized bed in the lower layer region 10a of the fluidized bed chamber 10, and the fine powder component Is blown up to the upper free board portion and reaches the upper layer region 10 b of the fluidized bed chamber 10. Thus, the raw material thrown into the fluidized bed type classifier 1 is classified into a coarse powder component and a fine powder component.

  The container 2 is provided with a coarse powder outlet 19 that opens to the lower layer region 10 a in the fluidized bed chamber 10, and a staying component outlet pipe 20 that is connected to the coarse powder outlet 19 with a space in the pipe. The lower layer region 10 a is a region near the partition member 3. Of the raw materials charged into the fluidized bed chamber 10, the component staying on the partition member 3, and thus the coarse powder component, is discharged from the coarse powder outlet 19 as indicated by an arrow D. At this time, not only the coarse powder component is discharged from the coarse powder discharge port 19, but a part of the fine powder component existing in the vicinity of the partition member 13 is discharged together with the coarse powder component.

  Further, the container 2 is provided with a fine powder discharge port 21 that opens to the upper layer region 10 b in the fluidized bed chamber 10, and a fine powder discharge pipe 22 that is connected to the fine powder discharge port 21 through a space in the pipe. The upper layer region 10b is a region in the vicinity of one end wall portion 5 disposed at the upper end portion of the container 2, and is the uppermost portion of the free board portion. Of the raw material charged into the fluidized bed chamber 10, the component blown up by the classification air, and hence the fine powder component, is discharged from the fine powder discharge port 21 as indicated by an arrow E.

  The discharge mechanism configured using the staying component discharge pipe 20 is a so-called chute, and a component staying while flowing in the lower layer region 10 a is discharged so as to flow out from the coarse powder discharge port 19. Therefore, as described above, the coarse powder component and the fine powder component staying in the lower layer region 10 a are discharged from the stay component discharge pipe 20.

  The discharge mechanism configured using the fine powder discharge pipe 22 is configured to discharge classified air to a pipe line extending upward from the container 2 and discharge it by gas conveyance using the classified air, and is blown up to the upper layer region 10b. The components are discharged through the fine powder discharge port 21 by the discharge power of the classified air. The components blown up by the classification air are adjusted in particle size when passing through the free board portion, and only the fine powder components are guided to the fine powder discharge port 22 and discharged from the fine powder discharge port 22.

  Thus, the raw material is classified into a coarse powder component and a fine powder component by adjusting the particle size in the free board portion. Only the fine powder component is discharged through the fine powder discharge port 21, and the coarse powder component including a part of the fine powder component is discharged through the coarse powder discharge port 19.

  The pulverizing equipment 30 pulverizes the raw material once with a roller mill 31, classifies the raw material pulverized with the roller mill 31 with the fluidized bed classifier 1, returns the coarse powder component to the roller mill 31 together with some fine powder components, and pulverizes again. In addition, the fine powder component is supplied to the tube mill 32 and further finely pulverized. The pulverization facility 30 further includes a raw material supply device 33, a dust collector 34 and a separator 35 in addition to the fluidized bed classifier 1, the roller mill 31 and the tube mill 32 described above.

  In the crushing facility 30, the raw material is first supplied from the raw material supply device 33 to the roller mill 31. The raw material supply device 33 is loaded into the raw material hopper 36 and transports the temporarily stored raw material through a raw material transport path 37 serving as a fixed amount feeder, and supplies the raw material to the roller mill 31. The raw material conveyance path 37 is configured by a belt conveyor or the like.

  The roller mill 31 is a vertical roller mill and includes a table liner and a grinding roller that is a grinding medium provided above the table liner. The table liner is driven to rotate about a vertical axis. The crushing roller is rotatable about an axis that intersects the axis of rotation of the table liner, is elastically pressed toward the table liner, and rotates with the rotation of the table liner. Such a roller mill 31 pulverizes the raw material supplied on the table liner with the crushing roller while rotating the table liner. The raw material pulverized by the roller mill 31 (hereinafter sometimes referred to as “coarse pulverized product”) is discharged from the roller mill 31 and is fluidized bed classifier by the coarse pulverized product conveyance path 38 configured using a bucket elevator or the like. 1 is conveyed.

  A classifier supply feeder 39 composed of a rotary feeder is provided in the raw material input pipe 18 of the fluidized bed type classifier 1. The rotary feeder is also called a rotary valve, and can prevent a gas such as air from passing therethrough and allow a solid such as a cement clinker to pass therethrough. The coarsely pulverized product from the roller mill 31 is airtightly supplied to the fluidized bed type classifier 1 from the raw material input pipe 18 via the classifier supply feeder 39. In the fluidized bed type classifier 1, the coarsely pulverized product is classified into a coarse powder component and a fine powder component, the fine powder component is discharged from the fine powder discharge port 21, and the coarse powder component and the fine powder component are discharged from the coarse powder discharge port 19. Discharged.

  The staying component discharge pipe 20 of the fluidized bed classifier 1 is provided with a classifier discharge feeder 45 composed of a rotary feeder, and the coarse powder component discharged from the fluidized bed classifier 1 through the coarse powder outlet 19. The fine powder component is airtightly discharged through the classifier discharge feeder 45. The coarse powder component and the fine powder component thus discharged are conveyed by the coarse powder circulation path 46, returned to the roller mill 31, and crushed again by the roller mill 31.

  The fine powder discharge pipe 22 of the fluidized bed type classifier 1 is connected to the dust collector 33 by the mixed fluid conveyance path 48, and the fine powder component discharged from the fluidized bed type classifier 1 via the fine powder discharge port 21 is together with the classified air. The mixed fluid is guided to the dust collector 33 by the mixed fluid conveyance path 48. The dust collector 33 is a device for separating a fluid in which a gas and a solid are mixed into a gas and a solid, and the mixed fluid in which a fine powder component and classified air are mixed into a fine powder component and classified air. To separate. Thus, the dust collector 33 is a device that collects the fine powder component from the mixed fluid, and is realized by, for example, a cyclone separator and / or a bag filter.

  The fine powder component collected by the dust collector 33 is hermetically discharged to the fine powder supply path 50 through the fine powder discharge feeder 49 formed of a rotary feeder, conveyed by the fine powder supply path 50, and supplied to the tube mill 32. The classified air separated from the fine powder component by the dust collector 33 is discharged to a predetermined discharge place through an exhaust passage 52 in which a fan 51 is interposed.

  The tube mill 32 has a rotating container and balls that are grinding media. The rotating container has a cylindrical shape provided horizontally, and is driven to rotate about its axis. A ball | bowl is a spherical member which is a hard sphere, for example, and is accommodated in a rotation container. The tube mill 32 puts the raw material into the rotating container, rotates the rotating container, and pulverizes the raw material with a pulverizing medium. The tube mill 32 is an apparatus having a finer pulverization efficiency than the roller mill 31, and the raw material supplied to the tube mill 32, that is, the fine powder component, is further finely pulverized by the tube mill 32.

  The finely pulverized product obtained by pulverizing the fine powder component supplied to the tube mill 32 is discharged from the tube mill 32 and conveyed to the separator 34 by the finely pulverized material conveyance path 55 configured using a bucket elevator or the like. . The separator 34 is an apparatus for dividing the finely pulverized product into fine powder having a particle size acceptable as a cement product and reprocessing powder that needs to be pulverized again. The separator 34 is realized by a cyclone separator, for example.

  The fine powder separated by the separator 34 is discharged as a cement product, which is a product, and is transported to a predetermined product storage place by the product transport path 56 and stored. The reprocessed powder required to be separated by the separator 34 is discharged separately from the fine powder, conveyed by the fine powder circulation path 57, and returned to the tube mill 32.

  FIG. 3 is a block diagram showing an electrical configuration of the crushing facility 30. FIG. 4 is a flowchart showing a control operation by the control circuit 62. Referring to FIGS. 1 and 2 together, the pulverization facility 30 further includes an air box pressure sensor 60, a fluidized bed chamber pressure sensor 61, and a control circuit 62.

  The wind box pressure sensor 60 is provided in the fluidized bed classifier 1 and detects the pressure of the classified air in the wind box, and thus the pressure of the classified air in the gas introduction chamber 11. The wind box pressure sensor 60 supplies the control circuit 62 with the detected pressure of classified air in the gas introduction chamber 11 (hereinafter referred to as “detected wind box pressure”) P1.

  The fluidized bed chamber pressure sensor 61 is a means that is provided in the fluidized bed classifier 1 and detects the pressure of classified air in the fluidized bed chamber 10, specifically, the free board section. The fluidized bed chamber pressure sensor 61 supplies the control circuit 62 with the detected pressure of classified air in the fluidized bed chamber 10 (hereinafter referred to as “detected fluidized bed chamber pressure”) P2.

  The control circuit 62 is a means for controlling the classifier discharge feeder 45, and is realized by a microcomputer. The control circuit 62 subtracts the detected fluidized bed chamber pressure P2 from the detected windbox pressure P1 based on the detected windbox pressure P1 and the detected fluidized bed chamber pressure P2 so that the detected differential pressure ΔP becomes a predetermined set differential pressure Pset. Thus, the classifier discharge feeder 45 which is a means for discharging the coarse powder component from the fluidized bed type classifier 1 is controlled. That is, the control circuit 62 controls the discharge flow rate Q2 by the classifier discharge feeder 45. Here, the classifier supply feeder 39 supplies the raw material to the fluidized bed classifier 1 at a constant supply flow rate Q1.

  The differential pressure ΔP is caused by pressure loss due to the partition member 3 and the fluidized bed, and the differential pressure also changes as the fluidized bed thickness changes. As the thickness of the fluidized bed increases, the pressure loss increases and the differential pressure ΔP increases. Conversely, as the fluidized bed thickness decreases, the pressure loss also decreases and the differential pressure ΔP decreases.

  Therefore, when the control circuit 62 starts the control at step a0, first, at step a1, the detected fluidized bed chamber pressure P2 is subtracted from the detected wind box pressure P1 to obtain the detected differential pressure ΔP and compared with the set differential pressure Pset. When the detected differential pressure ΔP is the same as the set differential pressure Pset, the control circuit 62 proceeds to step a2 and classifies so as to keep the discharge flow rate Q2 unchanged in order to maintain the fluidized bed thickness as it is. The machine discharge feeder 45 is controlled, the process proceeds to step a3 and the control is terminated. When the detected differential pressure ΔP is smaller than the set differential pressure Pset, the control circuit 62 proceeds to step a4 in order to increase the thickness of the fluidized bed, and sets the classifier discharge feeder 45 so as to decrease the discharge flow rate Q2. Control proceeds to step a3, and when the detected differential pressure ΔP is larger than the set differential pressure Pset, the process proceeds to step a5 to reduce the thickness of the fluidized bed, and the classifier is discharged so as to increase the discharge flow rate Q2. Control the feeder 45 and proceed to step a3. The control circuit 62 repeatedly executes such a series of control operations while the fluidized bed classifier 1 is in operation.

  By controlling the classifier discharge feeder 45 in this way, the layer thickness of the fluidized bed can be kept constant, and the differential pressure ΔP can be kept at the set differential pressure. By maintaining the differential pressure ΔP at the set differential pressure in this way, the flow velocity of classified air (hereinafter sometimes referred to as “classified flow velocity”) v in the free board section in the container 2 of the fluidized bed type classifier 1 is kept constant. Can be held.

  When classification air is blown into the coarsely pulverized product, if the classification flow rate v is equal to or higher than the fluidization rate v1, the coarsely pulverized product is fluidized to form a fluidized bed. When the classification flow velocity v becomes higher than the bubble generation speed v2 larger than the fluidization speed v1, bubbles are generated in the fluidized bed, resulting in a non-uniform flow state, but the fluidization speed v1 or more and less than the bubble generation speed v2 If it exists, the favorable uniform fluidization state in which particle | grains disperse | distribute uniformly can be obtained. When the classification flow velocity v becomes equal to or higher than the terminal velocity v3 which is larger than the bubble generation velocity v2, all particles are transported by the classification air, and the fluidized bed disappears.

  Here, the particle is a general term for coarse powder and fine powder constituting the coarsely pulverized product. The fluidization speed v1, the bubble generation speed v2, and the terminal speed v3 are dependent on the particle size, and increase as the particle size increases and decrease as the particle size decreases. Therefore, if the classification flow rate v is set to be equal to or higher than the final velocity v3 of the fine powder, equal to or higher than the fluidization speed of the coarse powder and lower than the final velocity v3, the coarsely pulverized product can be classified into the coarse powder component and the fine powder component. .

  Therefore, the classification particle size is determined by the classification flow rate v. Conversely, when the classification flow rate v changes, the classification particle size changes. In order to prevent this, as described above, the thickness of the fluidized bed is controlled so as to keep the classification flow velocity v constant. As a result, the classification particle size can be kept constant, and high classification accuracy can be secured.

  Furthermore, it is preferable that the classification flow velocity v is set to a fine powder end velocity v3 or more, a coarse powder fluidization velocity v or more and a bubble generation velocity v2 as much as possible. If set in this way, not only the fine powder component can be discharged by gas conveyance from the fine powder discharge port 21, but also the fluidized state of the fluidized bed formed on the partition member 3 is a uniform fluidized state, or It becomes a very close state, and a stable and good flow state can be obtained.

  If such a good flow state can be formed, the raw material input port 17 is formed in one place of the container 2 and the coarse powder discharge port 19 is formed in one place of the container 2, that is, the raw material The entire region on the partition member 3 can be obtained without a complicated configuration in which the inlet port 17 and the coarse powder outlet port 19 are uniformly dispersed and formed without inclining the partition member 3 or the like. A fluidized bed having a substantially uniform layer thickness can be formed. If such a fluidized bed is formed, the classification flow rate v becomes a uniform flow rate, and higher classification accuracy can be obtained.

  FIG. 5 is a flowchart showing a crushing method executed using the crushing equipment 30. The crushing procedure according to the crushing method starts from step s0 and proceeds to the coarse crushing step of step s1. In this coarse pulverization step, the raw material is pulverized by the roller mill 31, and the coarsely pulverized material as the pulverized raw material is supplied to the fluidized bed classifier 1.

  Next, the process proceeds to the classification step of step s2, and the classification air supplied to the gas introduction chamber 11 of the fluidized bed classifier 1 is applied to the coarsely pulverized product supplied to the fluidized bed chamber 10 of the fluidized bed classifier 1 from below. Infuse. In this way, in the fluidized bed classifier 1, by classifying air from below into the coarsely pulverized product, the coarse powder component is retained in the lower layer region 10a as described above to form a fluidized bed, and the fine powder component is added. It blows up to the upper layer area | region 10b. In this way, the coarse powder component and the fine powder component are classified, and the process proceeds to the raw material extraction step of step s3.

  In the raw material acquisition process, as described above, the fine powder component is discharged together with air from the upper layer region 10b and guided to the dust collector 33. The dust collector 33 separates the fine powder component and air, and collects and extracts the fine powder component. Further, as described above, the coarse powder component and the fine powder component staying together with the coarse powder component in the lower layer region 10a are discharged from the stay component discharge pipe 20 and taken out.

  Then, the process proceeds to the fine pulverization step of step s4, and the fine powder component collected by the dust collector 33 is supplied to the tube mill 32 and further pulverized. The coarse powder component discharged from the fluidized bed classifier 1 is returned to the roller mill 31 together with the fine powder component discharged along with the discharge of the coarse powder component, and is pulverized again. When this fine pulverization process is completed, the process proceeds to step s5, and the pulverization procedure is completed. In the crushing facility 30, the raw material is pulverized by repeating such a series of pulverization procedures.

  According to the present embodiment, the raw material is first pulverized by the roller mill 31, and the coarsely pulverized material as the pulverized raw material is supplied to the fluidized bed classifier 1. In the fluidized bed type classifier 1, a hollow container 2 is partitioned by a partition member 3, and a fluidized bed chamber 10 and a gas introduction chamber 11 are formed. Coarse pulverized material is supplied from the inlet 17 to the fluidized bed chamber 10, and classified air is supplied from the gas inlet 15 to the gas inlet chamber 11. The classified air supplied to the gas introduction chamber 11 passes through the through holes 13 formed in the partition member 3 and is jetted to the fluidized bed chamber 10, and the coarsely pulverized product on the partition member 3 is fluidized to generate a fluidized bed. Is formed. The fluidized bed is formed in a virtual region of the fluidized bed chamber 10, whereby the fluidized bed chamber 10 is divided into a fluidized bed portion in which the fluidized bed is formed and a free board portion above the fluidized bed portion. At this time, the coarse powder component having a large particle size stays while flowing on the partition member 3, and the fine powder component having a small particle size is blown upward. At this time, the coarse powder component and the fine powder component are not completely separated, but a part of the fine powder component stays together with the coarse powder component.

  The coarse powder component and fine powder component staying on the partition member 3 are discharged together from the coarse powder discharge port 19, returned to the roller mill 31, and pulverized again. The fine powder component blown up is conveyed to the classification air, discharged from the fine powder discharge port 21, supplied to the tube mill 32 through the dust collector 33, and further finely pulverized to produce a cement product.

  By providing the fluidized bed type classifier 1 in the pulverization facility 30, a part of the fine powder component is returned to the roller mill 31 together with the coarse powder component. When the coarse powder component and the fine powder component are mixed, the fine powder component particles enter between the coarse powder components and the porosity is reduced, so that the displacement of the grinding roller is reduced during the crushing in the roller mill 31 and the vibration level is lowered. To do. When the vibration is reduced, the reduction force of the pulverizing roller in the roller mill 31 can be maximized, so that the pulverization efficiency in the roller mill 31 is improved.

  Further, in the fluidized bed classifier 1, the fine powder component to be supplied to the tube mill 32 is discharged by gas conveyance. In the configuration in which the chute overflows as in the prior art, the particle size of the blown-up component cannot be adjusted between the partition member and the chute, so that the particle size of the raw material supplied to the roller mill 31 is increased, and When the flow rate of classification air is changed to change the type of cement product, the coarse powder component may be mixed with the fine powder component. On the other hand, as in the present invention, in the configuration of discharging by gas conveyance, the particle size of the blown-up component is adjusted in the free board portion, and the coarse powder component in the above-mentioned case that could not be solved by the conventional technology Splashing is prevented, and only the fine powder component is reliably discharged from the fine powder discharge port 22 and supplied to the tube mill 32. Therefore, compared with the case where it is necessary to consider that the coarse powder component is mixed, a ball having a small outer diameter and excellent pulverization efficiency can be used as the ball as the pulverization medium of the tube mill 32.

  For example, as an example, in the conventional equipment that assumes that the coarse powder component enters the tube mill 32, the outer diameter of the ball of the tube mill 32 must be about 50 to 17 mm, but only the fine powder component is present. In the case of the present invention to be supplied, the outer diameter of the pulverized body can be reduced to about 25 to several mm. In this way, in the tube mill 32, only the fine powder component can be pulverized, and the outer diameter of the ball can be reduced compared to the configuration that must be pulverized in consideration of the coarse powder component to be mixed. The contact area between the ball and the fine powder component is increased, and it becomes easy to pulverize to a fine particle size as a final product, and the pulverization efficiency in the tube mill 32 can be increased. Therefore, the grinding efficiency of the entire grinding equipment 30 can be increased.

  Thus, the fluidized bed classifier 1 is a conventional fluidized bed classifier that can return the fine powder component to the coarse pulverization apparatus together with the coarse powder component by improving the configuration for discharging the fine powder component. The achieved advantage can be maintained as it is, and furthermore, the coarse powder component can be prevented from being caught in the tube mill 32. Therefore, the advantage that the crushing efficiency in the roller mill 31 can be improved is maintained as it is, the crushing efficiency of the tube mill 32 is further improved, and the crushing efficiency of the whole crushing equipment 30 can be improved.

  Further, when the fluidized bed classifier 1 is examined in detail, the classification flow velocity v changes with the change of the fluidized bed thickness as described above. In the fluidized bed classifier 1, the particles that have reached the final velocity v3 are discharged from the fine powder outlet 21. Therefore, when the classification flow velocity v changes, the particle size of the particles discharged to the tube mill 31 side changes.

  Therefore, if the classification flow velocity v is set to the terminal velocity v3 of the particles having the maximum particle size among the fine powder components, the coarse powder components are discharged to the tube mill 31 side when the classification flow velocity v changes. In order to prevent this, if the classification flow velocity v is set to a flow velocity smaller than the terminal velocity v3 of the largest particle size among the fine powder components, the coarse powder components are discharged to the tube mill 31 side when the classification flow velocity v changes. However, in this case, particles having a particle size that can be sent to the tube mill 31 are also returned to the roller mill 31, causing a reduction in efficiency.

  Therefore, in the present embodiment, as described above, the discharge flow rate Q2 by the classifier discharge feeder 45 is controlled based on the detected differential pressure ΔP between the detected wind box pressure P1 and the detected fluidized bed chamber pressure P2, and the fluidized bed The layer thickness is controlled. By such control, the classification flow rate v can be kept constant, and the classification flow rate v can be set to the terminal velocity v3 of particles of the largest particle size among the fine powder components, or a velocity close thereto, Efficiency can be achieved.

  FIG. 6 is a cross-sectional view showing a fluidized bed type classifier 1A according to another embodiment of the present invention. FIG. 7 is a cross-sectional view taken along section line S7-S7 in FIG. FIG. 8 is a system diagram showing a pulverization facility 30A including a fluidized bed type classifier 1A. The crushing equipment 30A of the present embodiment is similar to the crushing equipment 30 of the above-described embodiment shown in FIGS. 1 to 5, and only different configurations will be described, and the same configurations will be described with the same reference numerals. Is omitted. The crushing equipment 30A of the present embodiment includes a fluidized bed type classifier 1A integrated with a separating means.

  In the fluidized bed classifier 1A, an exhaust port 21A that is a gas exhaust port is formed in the upper end wall portion 5 of the container 2, and an exhaust pipe 22A is provided. The structure itself of the exhaust port 21A and the exhaust pipe 22A is the same as that of the fine powder discharge port 21 and the fine powder discharge pipe 22 described above. Further, the fluidized bed classifier 1A has a centrifugal classifier 70 built in the fluidized bed chamber 10 as a centrifugal separator.

  The centrifugal classifier 70 includes a cone 71 and a fine powder introduction unit 72. The cone 71 is generally conical, and is provided on the end wall 5 at the top of the container 2 with the side corresponding to the bottom of the cone disposed upward and covering the exhaust port 21A. The fine powder introduction unit 72 has a plurality of guide vanes 73. Each guide vane 73 is provided on the top of the cone 71 in the circumferential direction of the cone 71, and is supported at the proximal end so as to be angularly displaceable as an arrow G around the same angular displacement axis as the axis of the cone 71. The cone 71 is provided so as to extend inward and in one circumferential direction.

  Between such guide vanes 73, an introduction passage 90 that communicates the inside and outside of the cone 71 is formed. Each of these introduction passages 90 is opened in the upper layer region 10b, and the fine powder component to be blown up can be conveyed into the classified air from the upper layer region 10b and introduced into the cone 71. The opening opened to the upper layer region 10b in each introduction passage 90 corresponds to the fine powder discharge port in the fluidized bed classifier 1 of the above-described embodiment.

  Further, the flow passage cross-sectional area of the introduction passage 90 can be changed by angularly displacing each guide vane 73. That is, each guide vane 73 achieves a function as a flow path changing piece. The mixed fluid introduced into the cone 71 of the centrifugal classifier 70 is separated into coarse powder components and classified air while swirling along the inner peripheral surface of the cone.

  A solid discharge port 74a is formed at the lower portion of the cone 71, and a fine powder discharge pipe 74 is connected. The fine powder component collected by the centrifugal classifier 70 can be discharged from the fluidized bed classifier 1A. The fine powder discharge pipe 74 is connected to the fine powder supply path 50 via a fine powder discharge feeder 76 formed of a rotary feeder, and the collected fine powder component is conveyed by the fine powder supply path 50 and supplied to the tube mill 32. The

  Since the classified air after the fine powder component has been collected may contain fine powder having the same particle size as that of the cement product, the exhaust pipe 22A has an exhaust passage 78 in which the fan 77 is interposed. Then, it is guided to the separator 34. Thus, in this embodiment, instead of the dust collector 33, the centrifugal classifier 70 is integrally provided in the fluidized bed classifier 1A.

  Also in this embodiment, the same effect as that of the above-described embodiment can be achieved. In addition, a centrifugal classifier 70 is provided in the fluidized bed chamber 11 of the fluidized bed classifier 1A. In the centrifugal classifier 70, the fine powder component blown up from the upper layer region is introduced into the cone 71 by being conveyed to the classification air, and the centrifugal force is used in the cone 71 to convert the classified air and the fine powder component. To separate.

  Such a fluidized bed classifier 1A operates in the same manner as the fluidized bed classifier 1 described with reference to FIGS. 1 to 5, and can return the fine powder component together with the coarse powder component to the coarse pulverizer. It is possible to achieve the same effect that the advantages achieved with the fluidized bed classifier of the prior art can be maintained as they are, and further, the spattering of the coarse powder component into the tube mill 32 can be prevented. Therefore, the pulverization facility 30A provided with the fluidized bed classifier 1A maintains the advantage that the pulverization efficiency in the roller mill 31 can be improved as in the pulverization facility 30 described with reference to FIGS. The effect that the pulverization efficiency of the pulverization facility 30 can be improved by improving the pulverization efficiency of 32 can be similarly achieved.

  In addition, since the fluidized bed classifier 1A is integrated with the centrifugal classifier 70, there is no need to separately provide a separating means for separating the fine powder component and the classified air. The fine powder component can be supplied to 32. By integrating the centrifugal classifier 70 in this way, the entire apparatus can be made compact and the equipment cost can be reduced. In addition, when the separation means is provided separately, wasteful energy consumption occurs due to pressure loss between the fluidized bed classifier 1A and the separation means, but the wasteful energy consumption is suppressed by integrating them. , Energy saving can be achieved.

  Further, the introduction passage 90 can change its flow path cross-sectional area by angularly displacing the guide vane 73. By changing the cross-sectional area of the flow path, it is possible to adjust the particle size of the fine powder component discharged together with the classified air from the exhaust port 21A. Since the particle size of the fine powder component introduced into the cone 71 can be adjusted in this way, when the mixed fluid introduced into the cone 71 is separated into the classified air and the fine powder component, the mixed air is trapped in the classified air. It is possible to make the fine powder component into a particle size that can be used as a product as it is. The fine powder component trapped in the classification air in this way can be collected and used as it is, that is, as a cement product, and is prevented from being excessively pulverized by being supplied to the tube mill 32 for pulverization, thereby further increasing the pulverization efficiency. can do.

  As still another embodiment of the present invention, the fluidized bed classifiers 1 and 1A may be provided with means for changing the flow velocity in the freeboard section without changing the flow velocity of the classified air in the fluidized bed. Good. Such means can be realized by means for changing the cross-sectional area of the free board part, for example, by displacing the inner diameter of the container in the free board part, for example, by displacing the variable member in the radial direction. With such a configuration, the control of the flow velocity of the classified air in the fluidized bed by controlling the flow rate difference ΔQ as described above, and the control of the flow velocity of the classified air in the free board portion by controlling the cross-sectional area of the free board portion. , Can be performed individually.

  In a fluidized bed type classifier, it is possible to adjust the classification particle size by changing the flow rate of the classification air to be blown, but if the flow rate in the fluidized bed changes as described above, the flow state changes. Then it may get worse. When the flow state deteriorates, the coarse powder component is mixed with the fine powder component, and the classification accuracy is lowered. In particular, in the configuration in which the fine powder component overflows into the chute and is discharged as in the prior art, the coarse powder component immediately becomes fine powder because it is greatly affected by the deterioration of the flow state when the classification air flow rate is changed. It gets mixed with ingredients. Therefore, if the classification particle size is changed depending on the type of cement product, etc., the classification accuracy is lowered, so that a wide range of cement types can be handled.

  On the other hand, in the configuration in which the fluidized bed portion and the freeboard portion are formed as in the present invention and discharged by gas conveyance, the particle size is adjusted in the freeboard portion, compared to the conventional overflow configuration, It is difficult to be affected by the deterioration of the flow state, and the classification particle size can be easily adjusted by changing the flow rate of the classification air. Furthermore, if the flow rate of classified air in the fluidized bed part and the flow rate of classified air in the free board part can be individually controlled, only the flow rate of the free board part is changed to ensure a good fluid state in the fluidized bed, In addition, the classification particle size can be changed.

  Therefore, it becomes easy to change the classification particle size according to the particle size of the coarsely pulverized product supplied from the roller mill 31 and the cement type. That is, it is possible to easily cope with a wide range of raw material classification while maintaining high classification accuracy.

  Each above-mentioned embodiment is only the illustration of this invention, and can change a structure within the scope of the present invention. For example, specific shapes and dimensions can be changed.

It is sectional drawing which shows the fluidized bed type classifier 1 of one Embodiment of this invention. It is a systematic diagram which shows the grinding | pulverization equipment 30 provided with the fluid bed type classifier 1. FIG. 3 is a block diagram showing an electrical configuration of the pulverization equipment 30. FIG. 3 is a flowchart showing a control operation by a control circuit 62. 3 is a flowchart showing a pulverization method executed using the pulverization facility 30. It is sectional drawing which shows the fluidized bed type classifier 1A of the other form of implementation of this invention. It is sectional drawing seen from cut surface line S7-S7 of FIG. It is a systematic diagram showing grinding equipment 30A provided with fluidized bed classifier 1A.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A Fluidized bed classifier 2 Container 3 Partition member 10 Fluidized bed chamber 11 Gas introduction chamber 13 Through-hole 30 Crushing equipment 31 Roller mill 32 Tube mill 70 Centrifugal type classifier 71 Cone 73 Guide vane

Claims (3)

A coarse crushing device for crushing raw materials;
A fine pulverizer for further pulverizing the raw material crushed by the coarse pulverizer;
A pulverization facility including a fluidized bed classifier provided between a coarse pulverizer and a fine pulverizer;
Fluidized bed classifier
A hollow container,
A plurality of through holes are formed, the container is partitioned vertically, and includes a partition member that forms an upper fluidized bed chamber and a lower gas introduction chamber,
A gas introduction port that is open to the gas introduction chamber and is supplied with a fluidizing gas that is ejected from the gas introduction chamber to the fluidized bed chamber through each through hole of the partition member;
An inlet to the fluidized bed chamber, to which raw materials crushed by a coarse pulverizer are supplied;
A fine powder discharge port that opens to the upper layer region in the fluidized bed chamber and is connected to the fine pulverization apparatus to convey and discharge the fine powder component to the fluidizing gas;
Open to the lower layer region in the fluidized bed chamber and connected to the coarse pulverization apparatus, and a coarse powder outlet for discharging the coarse powder component and the fine powder component is formed,
A classifier discharge feeder that discharges the coarse powder component and fine powder component discharged through the coarse powder discharge port;
A wind box pressure sensor for detecting the pressure of the fluidizing gas in the gas introduction chamber;
A fluidized bed chamber sensor for detecting the pressure of the fluidizing gas in the fluidized bed chamber;
Based on the detection results of the wind box pressure sensor and the fluidized bed chamber sensor, the classifier discharge feeder is set so that the detected differential pressure between the pressure in the gas introduction chamber and the pressure in the fluidized bed chamber becomes a preset differential pressure. A control circuit that controls and maintains a constant bed thickness of the fluidized bed ,
In the control circuit, the flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the coarse powder component is fluidized to form a fluidized bed. that above and such that the velocity less than that bubbles are generated in the fluidized bed velocity, grinding equipment characterized that you control the classifier discharge feeder. Between the coarse pulverization device for pulverizing the raw material and the fine pulverization device for further pulverizing the raw material pulverized by the coarse pulverization device, a fluidized bed type classification device for classifying the raw material pulverized by the coarse pulverization device is provided,
In the fluidized bed type classifier,
A hollow container is divided up and down by a partition member having a plurality of through holes, and an upper fluidized bed chamber and a lower gas introduction chamber are formed,
While introducing the raw material into the fluidized bed chamber, the fluidizing gas is introduced into the gas introducing chamber and ejected into the fluidized bed chamber through each through hole of the partition member,
The fine powder component is transported and discharged from the upper layer region of the fluidized bed chamber to the fluidizing gas, and supplied to the fine grinding device.
The coarse powder component and the fine powder component are discharged from the lower layer region of the fluidized bed chamber by the classifier discharge feeder, and supplied to the coarse pulverizer.
Detecting the pressure of the fluidizing gas in the gas introduction chamber by a windbox pressure sensor;
Detecting the pressure of the fluidizing gas in the fluidized bed chamber by a fluidized bed chamber sensor;
Based on the detection results of the wind box pressure sensor and the fluidized bed chamber sensor, the classifier discharge feeder is set so that the detected differential pressure between the pressure in the gas introduction chamber and the pressure in the fluidized bed chamber becomes a preset differential pressure. Control and keep the fluidized bed thickness constant ,
The flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the fluid velocity is higher than the speed at which the coarse powder component is fluidized to form a fluidized bed. such that the speed less than that bubbles are generated in the layer, pulverization wherein that you control the classifier discharge feeder. A hollow container,
A plurality of through holes are formed, partition the container up and down, and a partition member that forms an upper fluidized bed chamber and a lower gas introduction chamber;
Centrifuge means provided in the fluidized bed chamber,
The container
A gas introduction port that is open to the gas introduction chamber and is supplied with a fluidizing gas that is ejected from the gas introduction chamber to the fluidized bed chamber through each through hole of the partition member;
An inlet to the fluidized bed chamber for supplying raw materials;
A coarse powder outlet opening in the lower layer region in the fluidized bed chamber and discharging the coarse powder component and the fine powder component;
A gas outlet opening in the upper layer region in the fluidized bed chamber is formed,
The centrifuge means
A cone provided to cover the gas outlet, and a solid outlet for discharging fine powder at the lower end is formed;
An introduction passage is formed that opens to the upper layer region of the fluidized bed chamber, conveys the fine powder component to the fluidizing gas and introduces it into the cone, and a flow path changing piece for changing the flow passage cross-sectional area of the introduction passage. A fine powder introduction section,
A classifier discharge feeder that discharges the coarse powder component and fine powder component discharged through the coarse powder discharge port;
A wind box pressure sensor for detecting the pressure of the fluidizing gas in the gas introduction chamber;
A fluidized bed chamber sensor for detecting the pressure of the fluidizing gas in the fluidized bed chamber;
Based on the detection results of the wind box pressure sensor and the fluidized bed chamber sensor, the classifier discharge feeder is set so that the detected differential pressure between the pressure in the gas introduction chamber and the pressure in the fluidized bed chamber becomes a preset differential pressure. controlled, have a control circuit for holding the thickness of the fluidized bed constant,
In the control circuit, the flow velocity of the fluidizing gas in the container is equal to or higher than the speed at which all particles of the fine powder component are conveyed by the fluidizing gas, and the coarse powder component is fluidized to form a fluidized bed. The fluidized bed type classifier is characterized in that the classifier discharge feeder is controlled so as to be equal to or higher than a predetermined speed and lower than a speed at which bubbles are generated in the fluidized bed.

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