WO2021006154A1

WO2021006154A1 - Method for operating pulverizing system, and method for manufacturing powder

Info

Publication number: WO2021006154A1
Application number: PCT/JP2020/025852
Authority: WO
Inventors: 文典安藤; 遠藤　晃; 堀田　滋; 貴弘青木
Original assignee: 川崎重工業株式会社
Priority date: 2019-07-05
Filing date: 2020-07-01
Publication date: 2021-01-14
Also published as: JP7330786B2; EP3995216A1; EP3995216A4; JP2021010870A; CN114007751B; CN114007751A

Abstract

This method is for operating a pulverizing system that comprises: a vertical pulverizing machine for pulverizing a pulverization starting material; a pulverized material circulation path where pulverized material moves from a discharge port to a supply port of the pulverizing machine; a classifying machine that is provided in the pulverized material circulation path and separates the pulverized material into fine powder to serve as a product and coarse powder to be returned to the pulverizing machine; a collecting machine for recovering the fine powder; an air-extracting path connected to an upper portion of the pulverizing machine; an air-extracting fan for extracting air from the pulverizing machine to the air-extracting path at a set air extraction rate; and a dust collecting machine for separating powder from the extracted air of the pulverizing machine and feeding the powder to the pulverized material circulation path. The method includes finding the correlation between the rate of air extraction from the pulverizing machine and the fineness of the recovered fine powder, estimating an air extraction rate at which a desired fineness can be obtained on the basis of the correlation, and setting this air extraction rate as the set air extraction rate.

Description

How to operate the crushing system and how to manufacture powder

The present invention relates to a method for producing a powder obtained by crushing a crushing raw material with a vertical crusher and a method for operating a crushing system used therein.

Conventionally, a vertical crusher is known as a kind of crusher for drying and crushing a crushing raw material. Examples of the pulverized raw material include a cement raw material and calcium carbonate.

Patent Documents

1 and 2 disclose a crushing system including this type of vertical crusher.

Patent Document 1 discloses a closed circuit crushing type crushing system. This crushing system includes a vertical crusher with a built-in classifier. When the pulverized raw material is pulverized by a pulverizer, a pulverized product containing coarse powder and fine powder is produced. The coarse powder is once discharged from the crusher and then supplied again to the crusher for re-grinding. The fine powder passes through the classifier along with the rising gas in the crusher, and is classified into refined powder and others by the classifier. The refined powder is discharged from the crusher along with the gas, collected by the dust collector, and then collected as a product. The gas separated from the fine powder by the dust collector is returned to the crusher.

The crushing system of Patent Document 2 includes a classifier independent of the vertical crusher. Of the crushed material of the crusher, the fine powder is discharged from the crusher along with the gas extracted from the crusher, and is separated from the gas by the dust collector. The gas separated from the fine powder by the dust collector is returned to the crusher, and the fine powder is sent to the classifier by a conveyor. Of the crushed material of the crusher, the coarse powder is sent to the classifier by a conveyor. The crushed material sent to the classifier is classified into fine powder and other parts, and the fine powder is collected as a product by the dust collector in the subsequent stage, and the other parts are returned to the crusher. In the crushing system of Patent Document 2, since the crushed product circulation system of the crusher and the gas circulation system of the crusher are independent, the amount of air extracted from the crusher and the amount of classified air of the classifier are independent. Can be adjusted.

Japanese Unexamined Patent Publication No. 9-117685 JP-A-2018-202347

The present invention is a further development of the invention described in Patent Document 2, and an object of the present invention is to use a closed circuit crushing system including a vertical crusher to arbitrarily adjust the degree of powder (powder). The purpose is to provide the technology for manufacturing the body).

The method of operating the crushing system according to one aspect of the present invention is as follows.
A vertical crusher that crushes crushed raw materials,
A crushed material circulation path for crushed material to move from the discharge port to the supply port of the vertical crusher, and
A classifier provided in the crushed product circulation path to separate the crushed product into a refined powder as a product and a coarse powder returned to the vertical crusher.
A collector that collects the fine powder and
The bleeding path connected to the upper part of the vertical crusher and
An bleeding fan that draws air from the vertical crusher to the bleeding path with the set bleeding air volume, and
A method of operating a crushing system including a dust collector that separates fine powder from the bleed air of the vertical crusher and sends it to the crushed material circulation path.
The correlation between the amount of air extracted from the vertical crusher and the degree of powderiness of the collected fine powder is obtained, the amount of air extracted from which the desired degree of powder is obtained is estimated based on the correlation, and the amount of air extracted is calculated as described above. It is characterized by setting the bleed air volume.

Further, in the method for producing a powder according to one aspect of the present invention, a pulverized raw material is supplied to a vertical crusher to be pulverized, and fine powder is extracted from the vertical pulverizer at a set bleed air volume to obtain fine powder. It is carried out on an air stream, the fine powder is separated from the air flow and transported to a classifier by a transporter, and the rest of the crushed material is transported to the classifier by the transporter and set by the classifier. The pulverized product is classified into refined powder and coarse powder according to the particle size, the refined powder is airborne from the classifier to the collector and collected as a product by the collector, and the coarse powder is collected by the classifier. Includes returning from to the vertical crusher and re-crushing. Then, the correlation between the amount of air extracted from the vertical crusher and the degree of powderiness of the collected fine powder is obtained, and the amount of air extracted from which a desired degree of powder is obtained is estimated based on the correlation. Is the set bleed air volume.

According to the operation method of the crushing system and the powder production method, the refined powder (powder) having an arbitrary degree of powder can be obtained by changing the set bleed air volume. That is, it is possible to obtain a powder product according to the purpose of use by changing the degree of powderiness of the obtained refined powder. As a result, the quality of the powder product can be improved.

According to the present invention, it is possible to provide a technique for producing refined powder (powder) having an arbitrarily adjusted degree of powder by using a closed circuit crushing system including a vertical crusher.

FIG. 1 is a diagram showing an overall configuration of a crushing system according to an embodiment of the present invention. FIG. 2 is a diagram showing a configuration of a second experimental device simulating a conventional crushing system. FIG. 3 is a chart showing the correlation between the amount of air extracted from the vertical crusher and the degree of powderiness of the collected refined powder. FIG. 4 is a chart showing a characteristic curve of the electric power intensity of the vertical crusher with respect to the amount of air extracted from the vertical crusher.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a crushing system 1 according to an embodiment of the present invention.

The closed circuit type crushing system 1 shown in FIG. 1 includes a vertical crusher 2 (hereinafter, simply referred to as “crusher 2”), a crushed material circulation system 3 connected to the crusher 2, and a crusher 2. It includes a connected gas circulation system 4.

[Vertical crusher 2]
The crusher 2 includes a housing 21 that forms a crushing chamber 20 in which the crushing raw material is crushed. Inside the housing 21, a rotary table 22 that rotates around a vertical rotation axis and a plurality of crushing rollers 23 that are pressed against the rotary table 22 by a pressurizing means (not shown) and rotate in a driven manner are provided. Below the housing 21, a mill motor 24, which is a rotational drive source for the rotary table 22, and a reduction mechanism 25 for transmitting the rotational power of the mill motor 24 to the rotary table 22 are provided. The crusher 2 does not have a built-in classifier.

A supply port 26 is provided on the upper part of the housing 21. The pulverized raw material is introduced into the upper surface of the rotary table 22 through the supply port 26. Further, an air extraction port 27 is provided above the rotary table 22 and above the housing 21. Through the air extraction port 27, the fine powder generated by crushing the crushed raw material is discharged on the airflow that blows up. A discharge port 28 is provided below the rotary table 22. The crushed material that overflows from the outer peripheral edge of the rotary table 22 is discharged to the outside of the crusher 2 through the discharge port 28. A hot air outlet 29 is provided around the outer circumference of the rotary table 22. Hot air blows upward from the hot air outlet 29 into the crushing chamber 20.

[Crushed material circulation system 3]
The crushed product circulation system 3 is configured to separate the refined powder as a product from the crushed product discharged from the discharge port 28 of the crusher 2 and return the crushed product from which the refined powder is separated to the crushed product 2. .. The refined powder separated by the pulverized product circulation system 3 is recovered as a product.

The crushed material circulation system 3 has a crushed material circulation path 30 in which the crushed material discharged from the crusher 2 moves from the discharge port 28 of the crusher 2 to the supply port 26. A classifier 7 is provided in the crushed material circulation path 30. Further, in the present embodiment, since the crushed material inlet 71 of the classifier 7 is located above the discharge port 28 of the crusher 2, the crushed material 31 transports the crushed material upward from the discharge port 28 to the crushed material inlet 71. Is provided in the crushed material circulation path 30. The conveyor 31 according to the present embodiment is a bucket elevator including a plurality of buckets (not shown).

The discharge port 28 of the crusher 2 is connected to the first inlet 31a of the conveyor 31 via the passage 30a. The carrier 31 carries the crushed material charged through the first inlet 31a and the second inlet 31b, which will be described later, upward and discharges it from the outlet 31c. The outlet 31c of the conveyor 31 is connected to the crushed material inlet 71 of the classifier 7 via the passage 30b. A distribution damper (not shown) may be provided in the passage 30b connecting the transporter 31 and the classifier 7. Then, a part of the crushed material may be directly conveyed to the supply port 26 of the crusher 2 by the distribution damper without going through the classifier 7.

The classifier 7 classifies the supplied crushed product into refined powder and coarse powder according to the set particle size. The set particle size of the "fine powder" is determined according to the particle size of the recovered product. The “coarse powder” here means a pulverized product supplied to the classifier 7 having a particle size larger than that of the refined powder. In the present embodiment, the airflow type classifier 7 is adopted as the classifier 7. However, the classifier 7 is not limited to the airflow type classifier as long as the pulverized product can be classified into refined powder and others according to the particle size.

The crushed material classified into coarse powder by the classifier 7 is discharged from the discharge port 72. The discharge port 72 is connected to the supply port 26 of the crusher 2 via the passage 30c.

The crushed material classified into fine powder by the classifying machine 7 is discharged from the exhaust port 73 on the air flow. The exhaust port 73 is connected to the inlet of the collector 6 via the passage 64. A classification fan 66 is provided in the exhaust passage 65 of the collector 6. The exhaust air volume of the classification fan 66 is adjusted so as to have a predetermined classification air volume F2.

The collector 6 collects the fine powder accompanying the gas discharged from the classifier 7 and separates the fine powder from the gas. In this embodiment, a bug filter is adopted as the collector 6. However, the collector 6 is not limited to the bug filter as long as it can collect the fine powder accompanying the gas.

[Gas circulation system 4]
The gas circulation system 4 is configured to separate fine powder from the exhaust gas of the crusher 2 and return the separated gas to the crusher 2 as hot air.

The gas circulation system 4 has a gas circulation path 40 through which the gas extracted from the crusher 2 flows from the air extraction port 27 of the crusher 2 to the hot air inlet 29a. The gas circulation path 40 is provided with a dust collector 41 that separates fine powder from the air extracted from the crusher 2, an air extraction fan 42, and a hot air supply source 43 that supplies hot air to the gas circulation path 40. The exhaust air volume of the bleed air fan 42 is adjusted to be the bleed air volume F1.

The air extraction port 27 of the crusher 2 is connected to the inlet of the dust collector 41 via the air extraction path 40a. The outlet of the dust collector 41 is connected to the hot air inlet 29a of the crusher 2 via the passage 40b. A hot air supply source 43 is connected to the passage 40b.

The dust collector 41 separates fine powder from the bleed air (hereinafter referred to as "mill exhaust") from the crusher 2. In the present embodiment, as the dust collector 41, a cyclone type dust collector that utilizes the suction action of the bleed air fan 42 is adopted. However, the dust collector 41 is not limited to the cyclone type dust collector as long as it can separate fine powder from the mill exhaust.

The fine powder outlet of the dust collector 41 is connected to the second inlet 31b of the conveyor 31 via the fine powder transport path 88. The fine powder separated from the mill exhaust by the dust collector 41 is sent to the transport machine 31 through the transport path 88.

In the passage 40b connected to the outlet of the dust collector 41, a passage 84 for sending the mill exhaust of the passage 40b to the classifier 7 is connected to the downstream side of the flow of the mill exhaust from the bleeding fan 42. A flow rate adjusting device 85 for adjusting the flow rate of the mill exhaust gas flowing to the classifier 7 is provided in the passage 84. By changing the opening degree of the flow rate adjusting device 85, the flow rate of the mill exhaust gas flowing to the classifier 7 can be adjusted, and as a result, the flow rate of the mill exhaust gas returned to the crusher 2 can be adjusted. The flow rate adjusting device 85 may be, for example, at least one of a damper, a flow rate adjusting valve, and a fan, regardless of the mode, as long as it is a means for adjusting the flow rate of the mill exhaust gas flowing to the classifier 7.

The hot air supply source 43 may be, for example, a hot air generator that generates hot air at a desired temperature. The hot air supplied from the hot air supply source 43 to the gas circulation path 40 is sent to the hot air inlet 29a of the crusher 2 through the passage 40b together with the mill exhaust. However, the hot air supply source 43 is not limited to the hot air generator, and for example, when a source of high temperature gas such as a kiln (cement firing furnace) exists around the crusher 2, the hot air source is used. It may be used as a hot air supply source 43.

[Powder production method using crushing system 1]
Here, an operation method of the crushing system 1 having the above configuration and a method of producing powder using the crushing system 1 will be described. In the crusher 2, the inside of the crushing chamber 20 including the rotary table 22 and the crushing roller 23 is preheated by the hot air blown from the hot air outlet 29. Then, the rotary table 22 is rotationally driven by the mill motor 24, and a plurality of crushing rollers 23 whose peripheral surfaces are pressed against the crushing surface (upper surface) of the rotary table 22 are driven to rotate. The pulverized raw material is supplied onto the rotary table 22 rotating in this way through the supply port 26. The crushing raw material is crushed between the rotary table 22 and the crushing roller 23. Of the crushed material, the coarse powder overflows from the peripheral edge of the rotary table 22 and is discharged to the outside of the machine through the discharge port 28. Further, the fine powder of the pulverized product is discharged from the extraction port 27 on the airflow that blows up.

The mill exhaust gas from the air extraction port 27 of the crusher 2 flows into the dust collector 41. In the dust collector 41, the fine powder accompanying the mill exhaust is separated from the mill exhaust. The separated fine powder is sent to the second inlet 31b of the transport machine 31 through the transport path 88 and joins the flow of the crushed material in the crushed material circulation system 3.

On the other hand, the mill exhaust from which the fine powder is separated by the dust collector 41 exits from the dust collector 41, is sucked into the bleed air fan 42, and is sent to the passage 40b further downstream of the gas circulation system 4. Here, the opening degree of the flow rate adjusting device 85 is adjusted in order to balance the flow rate of the mill exhaust gas flowing into the passage 40b by the suction action of the bleeding fan 42 and the flow rate of the mill exhaust gas returned to the crusher 2. The hot air supplied from the hot air supply source 43 to the passage 40b flows into the crusher 2 together with the mill exhaust, and is blown into the mill from the hot air outlet 29.

The crushed material discharged from the discharge port 28 of the crusher 2 is conveyed upward by the conveyor 31 and flows into the classifier 7. In the classifier 7, the pulverized product is classified and the fine powder is separated from the pulverized product. The crushed product from which the fine powder has been separated by the classifier 7 is discharged from the classifier 7, sent to the supply port 26 of the crusher 2 through the passage 30c, and crushed again by the crusher 2. The refined powder separated from the crushed material by the classifying machine 7 is discharged from the exhaust port 73 of the classifying machine 7 together with the gas, and is air-flowed to the collector 6 through the passage 64. The collector 6 collects the fine powder. This refined powder is collected as a product and, for example, packed in a bag. On the other hand, the gas separated from the fine powder by the collector 6 flows out to the exhaust passage 65 and is released to the atmosphere.

[Powder degree adjustment]
The degree of powderiness (degree of fineness of particles) of the refined powder recovered as a product as described above is one of the important factors indicating the quality of the refined powder. In the crushing system 1 having the above configuration, the degree of powderiness of the obtained refined powder can be changed by adjusting the bleed air volume F1. The following verification experiment was conducted in order to verify that the powderiness of the fine powder can be adjusted by adjusting the bleed air volume F1.

In the verification experiment, a first experimental device simulating the crushing system 1 according to the present embodiment and a second experimental device 101 (see FIG. 2) simulating a conventional crushing system were used.

The first experimental apparatus simulates the crushing system 1 shown in FIG. 1, and detailed description thereof will be omitted. The experiments of Examples 1 to 4 were carried out using the first experimental apparatus. Table 1 shows the experimental conditions of Examples 1 to 4 and Comparative Example 1. In Examples 1 to 4, the classified air volume F2 was kept constant at 15 [m ³ / min]. In Example 1, the bleed air volume F1 is 0 [m ³ / min], in Example 2, the bleed air volume F1 is 3 [m ³ / min], and in Example 3, the bleed air volume F1 is 6 [m ³ / min]. In No. 4, the extracted air volume F1 was set to 9 [m ³ / min]. The bleed air volume F1 is the exhaust air volume of the bleed air fan 42, and the classification air volume F2 is the exhaust air volume of the classification fan 66.

FIG. 2 is a diagram showing the configuration of the second experimental device 101. The second experimental device 101 includes a vertical crusher 102, a collector 106 connected to the exhaust port 127 of the crusher 102, and a classification fan 166 that sucks the exhaust gas of the crusher 102 into the collector 106. .. The crusher 102 includes a housing 121 forming a crushing chamber 120, a rotary table 122 that rotates around a vertical rotation axis, and a plurality of crushing rollers 123 that are driven by pressure contact with the rotary table 122 by a pressurizing means (not shown). , A mill motor 124 which is a rotation drive source of the rotary table 122, a speed reduction mechanism 125 which transmits the rotational power of the mill motor 124 to the rotary table 122, and a classifier 107 provided above the crushing roller 123 in the housing 121. ..

In the crusher 102, the crushing raw material supplied onto the rotating rotary table 122 is crushed between the rotary table 22 and the crushing roller 23 while being dried by hot air. Of the pulverized material, the fine powder is carried to the classifier 107 by the airflow blowing up from below, and is classified into the refined powder and the others by the classifier 107. The fine powder is discharged from the exhaust port 127 in the air stream and collected by the collector 106. The fine powder classified by the classifying machine 107 other than the refined powder and the coarse powder overflowing from the peripheral edge of the rotary table 122 are temporarily discharged to the outside of the machine and supplied to the crushing machine 102 again together with the new crushing raw material.

The experiment of Comparative Example 1 was carried out using the second experimental device 101 having the above configuration. In Comparative Example 1, the classified air volume F2 was kept constant at 15 [m ³ / min]. The classification air volume F2 is the air volume of the classification fan 166. In the second experimental device 101, it is difficult to adjust only the extracted air volume because the extracted air volume (exhaust air volume) from the crusher 102 is directly affected by the classified air volume F2.

In the experiments of Examples 1 to 4 and Comparative Example 1, the pulverized raw material was put into the mill of the experimental apparatus, and the fine powder was recovered. The collected fine powder sample was subjected to a specific surface area test and a net sieving test based on JIS R 5201 (physical test method for cement) in order to specify the degree of powder. In the specific surface area test, the specific surface area of the sample [cm ² / g] was measured using a specific surface area tester (brain air permeation measuring device). In the net sieving test, the sample is sifted using a test sieve having a mesh size of 45 μm, the residue on the sieve is weighed, and the residue of the sample mesh sieve [%] (hereinafter, the content of particles having a particle size of 45 μm or more). (Referred to as "45 μR") was calculated.

FIG. 3 is a chart showing the correlation between the amount of air extracted from the crusher 2 and the degree of powderiness of the recovered fine powder. The vertical axis of this chart represents the specific surface area [cm ² / g], the horizontal axis represents 45 μR [%], and the results of the powderness test of the fine powder obtained in Examples 1 to 4 and Comparative Example 1 are plotted. ing. Common to Examples 1 to 4 and Comparative Example 1, at a constant bleed air volume F1, the specific surface area decreases as the value of 45 μR increases. Further, at a constant 45 μR, the specific surface area decreases as the extracted air volume F1 increases.

The value of specific surface area is affected by the fine powder in the refined powder. From the result that the specific surface area decreases as the bleed air volume F1 increases when 45 μR is a constant value, the fine powder content decreases as the bleed air volume F1 increases, and the distribution width becomes narrower. Understand. In other words, it can be seen that the powderiness (specific surface area) of the refined powder can be adjusted by adjusting the bleed air volume F1.

Further, with respect to Examples 1 to 4 and Comparative Example 1, the electric power intensity for producing the refined powder was measured. As the power intensity, the power intensity of the

mill motors

24 and 124 was measured. The electric power intensity of the

mill motors

24 and 124 accounts for most of the electric power intensity for producing refined powder.

FIG. 4 is a chart showing a characteristic curve of the electric power intensity of the crusher 2 with respect to the extracted air volume F1 from the crusher 2 related to the production of the refined powder in Examples 1 to 4 and Comparative Example 1. The vertical axis of this chart represents the ratio of the power intensity [kWh / t (DB)] of Examples 1 to 4 when the power intensity [kWh / t (DB)] of Comparative Example 1 is 100%. , The vertical axis represents the bleed air volume F1 [m ³ / min].

The electric power intensity of Examples 1 to 4 is lower than that of Comparative Example 1. Further, when the bleed air volume F1 is less than about 4.5 m ³ / min, the electric power basic unit gradually decreases as the bleed air volume F1 increases, and when the bleed air volume F1 is about 4.5 m ³ / min or more, the bleed air volume F1 increases. Along with this, the power intensity gradually increases. In particular, in the range where the bleed air volume F1 is about 2 to 6 m ³ / min, the electric power intensity is reduced by about 30% as compared with the comparative example, and the electric power reduction effect is remarkable. It is presumed that this is because the over-crushing is suppressed by extracting the fine powder from the inside of the crusher 2 together with the extraction air, and as a result, the electric power intensity is reduced. From the viewpoint of such reduction of power intensity, it is clear that there is a suitable range for the extracted air volume F1.

From the results of the above verification experiments, it was verified that the powderiness (specific surface area) of the fine powder can be adjusted by adjusting the amount of air extracted from the crusher 2 F1. Further, it was verified that the electric power intensity of the mill motor 24 can be reduced by preventing over-crushing by adjusting the bleed air volume F1 from the crusher 2.

In the operation method of the crushing system 1 according to the present embodiment, the powderiness of the refined powder is adjusted by using the verified principle. That is, the operation method of the crushing system 1 according to the present embodiment includes a crusher 2 for crushing the crushed raw material, a crushed material circulation path 30 for moving the crushed material from the discharge port 28 of the crusher 2 to the supply port 26, and crushing. A classifier 7 provided in the material circulation path 30 for separating the crushed material into a refined powder as a product and a coarse powder returned to the crusher 2, a collector 6 for collecting the crushed powder, and an upper part of the crusher 2. It includes a connected bleed air passage 40a, an bleed air fan 42 that bleeds air from the crusher 2 to the bleed air passage 40a with a set bleed air volume, and a dust collector 41 that separates fine powder from the pulverized air of the crusher 2 and sends it to the crushed material circulation path 30. In the operation method of the crushing system, the correlation (see FIG. 3) between the amount of air extracted from the crusher 2 and the degree of powderiness of the recovered fine powder is obtained, and the desired degree of powderiness is obtained based on the correlation. The extracted air volume is estimated, and the extracted air volume F1 is set as the set extracted air volume.

Further, in the method for producing a powder using the pulverization system 1 according to the present embodiment, the pulverized raw material is pulverized by the pulverizer 2 and extracted from the pulverizer 2 at a set bleed air volume to blow out the fine powder among the pulverized products. The fine powder is separated from the bleed air of the crusher 2 and transported to the classifying machine 7, and the rest of the crushed material is transported from the crushing machine 2 to the classifying machine 7 and crushed by the classifying machine 7 according to the set particle size. This includes classifying a product into fine powder and coarse powder, collecting the fine powder as a product, and returning the coarse powder from the classifying machine 7 to the crushing machine 2 for re-grinding. Then, the correlation between the amount of air extracted from the crusher 2 and the degree of powderiness of the collected fine powder (see FIG. 3) is obtained, and the amount of air extracted from which the desired degree of powder is obtained is estimated based on the correlation. The bleed air volume is set as the set bleed air volume.

According to the above powder manufacturing method, refined powder (powder) having an arbitrary degree of powder can be obtained by changing the set bleed air volume. That is, it is possible to obtain a powder product according to the purpose of use by changing the degree of powderiness of the obtained refined powder. As a result, the quality of the powder product can be improved.

Further, in the operation method of the crushing system 1 and the powder manufacturing method according to the present embodiment, a characteristic curve (see FIG. 4) of the electric power intensity of the crusher 2 with respect to the extracted air volume is obtained, and a desired characteristic curve is obtained based on the characteristic curve. The set bleed air volume is defined as the bleed air volume at which the degree of powder is obtained and the electric power intensity is the minimum.

As a result, in addition to improving the quality of the refined powder (powder), it is possible to reduce the electric power intensity required for producing the refined powder (powder).

Hereinafter, an application example of the powder manufacturing method according to the present embodiment will be described.

When the crushed raw material is a cement raw material of a cement type containing a large amount of a mixture such as limestone, fine powder is likely to be generated because the limestone is softer than clinker, and the value of the specific surface area of the refined powder is the value specified as the cement raw material. Tends to be higher than. In such a case, by increasing the bleed air volume F1, the value of the specific surface area of the refined powder can be lowered within the specified value while maintaining 45 μR of the refined powder at a predetermined value. As a result, the quality of the cement raw material can be improved.

Further, when the crushed raw material is a cement raw material of a cement type (Portland cement, etc.) having a relatively small mixture of limestone or the like, the value of the specific surface area of the refined powder tends to be lower than the value specified as the cement raw material. is there. In such a case, by reducing the bleed air volume F1, the value of the specific surface area of the refined powder can be increased within the specified value while maintaining 45 μR of the refined powder at a predetermined value. As a result, the quality of the cement raw material can be improved.

In the above, there is a range in the bleed air volume F1 in which the value of the specific surface area of the refined powder is within the specified value range. Therefore, by using the characteristic curve of the electric power intensity with respect to the extracted air volume F1 (see FIG. 4) and adopting the extracted air volume F1 having the smallest electric power intensity to obtain the desired powderiness, the cement raw material can be used. In addition to improving the quality of electricity, it is possible to reduce the power intensity.

1: Crushing system 2: Vertical crusher 3: Crushed material circulation system 4: Gas circulation system 6: Collector 7: Classifier 20: Crushing chamber 21: Housing 22: Rotating table 23: Crushing roller 24: Mill motor 25: Deceleration mechanism 26: Supply port 27: Exhaust port 28: Discharge port 29: Hot air outlet 29a: Hot air inlet 30: Crushed

material circulation passages

30a, 30b, 30c: Passage 31: Conveyor 31a: First inlet 31b: Second inlet 31c: Outlet 40: Gas circulation path 40a: Extraction path 40b: Passage 41: Dust collector 42: Blower 43: Hot air supply source 64: Passage 65: Exhaust path 66: Blower 71: Crushed material inlet 72: Discharge port 73: Exhaust Port 84: Passage 85: Flow control device 88: Transport path 101: Second experimental device 102: Vertical crusher 106: Collector 107: Classifier 120: Crushing chamber 121: Housing 122: Rotating table 123: Crushing roller 124 : Mill motor 125: Reduction mechanism 127: Exhaust port 166: Blower

Claims

A vertical crusher that crushes crushed raw materials,
A crushed material circulation path for crushed material to move from the discharge port to the supply port of the vertical crusher, and
A classifier provided in the crushed product circulation path to separate the crushed product into a refined powder as a product and a coarse powder returned to the vertical crusher.
A collector that collects the fine powder and
The bleeding path connected to the upper part of the vertical crusher and
An bleeding fan that draws air from the vertical crusher to the bleeding path with the set bleeding air volume, and
A method of operating a crushing system including a dust collector that separates fine powder from the bleed air of the vertical crusher and sends it to the crushed material circulation path.
The correlation between the amount of air extracted from the vertical crusher and the degree of powderiness of the collected fine powder is obtained, the amount of air extracted from which the desired degree of powder is obtained is estimated based on the correlation, and the amount of air extracted is calculated as described above. Set air volume,
How to operate the crushing system.
The characteristic curve of the electric power intensity of the vertical crusher with respect to the extracted air volume is obtained, and the extracted air volume at which the desired powderiness can be obtained based on the characteristic curve has the smallest electric power intensity. Air volume,
The method of operating the crushing system according to claim 1.
The crushed raw material is crushed by a vertical crusher, and by extracting air from the vertical crusher with a set bleed air volume, fine powder of the crushed material is carried out on an air stream, and the fine powder is extracted from the bleed air of the vertical crusher. Separated and transported to a classifier, the balance of the crushed product is transported from the vertical crusher to the classifier, and the crushed product is classified into refined powder and coarse powder according to the set particle size by the classifier. , A method for producing a powder, which comprises collecting the refined powder as a product, returning the crude powder from the classifier to the vertical crusher, and pulverizing the coarse powder.
The correlation between the amount of air extracted from the vertical crusher and the degree of powderiness of the collected fine powder is obtained, the amount of air extracted from which the desired degree of powder is obtained is estimated based on the correlation, and the amount of air extracted is calculated as described above. Set air volume,
Powder manufacturing method.
The characteristic curve of the electric power intensity of the vertical crusher with respect to the extracted air volume is obtained, and the extracted air volume at which the desired powderiness can be obtained based on the characteristic curve has the smallest electric power intensity. Air volume,
The method for producing a powder according to claim 3.