CN114007751B - Method for operating pulverizing system and method for producing powder - Google Patents
Method for operating pulverizing system and method for producing powder Download PDFInfo
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- CN114007751B CN114007751B CN202080045585.2A CN202080045585A CN114007751B CN 114007751 B CN114007751 B CN 114007751B CN 202080045585 A CN202080045585 A CN 202080045585A CN 114007751 B CN114007751 B CN 114007751B
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- 239000000843 powder Substances 0.000 title claims abstract description 200
- 238000010298 pulverizing process Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 239000000463 material Substances 0.000 claims abstract description 75
- 238000000605 extraction Methods 0.000 claims abstract description 66
- 239000000428 dust Substances 0.000 claims abstract description 25
- 238000005086 pumping Methods 0.000 claims abstract description 4
- 239000002994 raw material Substances 0.000 claims description 24
- 239000002245 particle Substances 0.000 claims description 11
- 239000004568 cement Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 12
- 230000007246 mechanism Effects 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 235000019738 Limestone Nutrition 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000006028 limestone Substances 0.000 description 3
- 230000037361 pathway Effects 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
- B02C15/04—Mills with pressed pendularly-mounted rollers, e.g. spring pressed
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/08—Separating or sorting of material, associated with crushing or disintegrating
- B02C23/10—Separating or sorting of material, associated with crushing or disintegrating with separator arranged in discharge path of crushing or disintegrating zone
- B02C23/12—Separating or sorting of material, associated with crushing or disintegrating with separator arranged in discharge path of crushing or disintegrating zone with return of oversize material to crushing or disintegrating zone
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
- B02C23/20—Adding fluid, other than for crushing or disintegrating by fluid energy after crushing or disintegrating
- B02C23/22—Adding fluid, other than for crushing or disintegrating by fluid energy after crushing or disintegrating with recirculation of material to crushing or disintegrating zone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
- B02C23/24—Passing gas through crushing or disintegrating zone
- B02C23/34—Passing gas through crushing or disintegrating zone gas being recirculated to crushing or disintegrating zone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C25/00—Control arrangements specially adapted for crushing or disintegrating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
- B02C2015/002—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs combined with a classifier
Abstract
A method for operating a pulverizing system, the pulverizing system comprising: a vertical pulverizer for pulverizing a pulverized material, a pulverized material circulation path through which a pulverized material is fed to move from a discharge port of the pulverizer to a feed port, and a classifier provided in the pulverized material circulation path and dividing the pulverized material into fine powder as a product and coarse powder returned to the pulverizer; a collector for recovering fine powder; the air pumping channel is connected to the upper part of the pulverizer; an air extraction fan for extracting air from the pulverizer to the air extraction path by setting air extraction volume; and a dust collector for separating the fine powder from the air suction of the pulverizer and conveying the fine powder to the pulverized material circulation path, wherein a correlation between the air suction volume of the pulverizer and the powder degree of the fine powder to be recovered is obtained, the air suction volume of the fine powder to be recovered is estimated based on the correlation, and the air suction volume is used as a set air suction volume.
Description
Technical Field
The present application relates to a method for producing a powder by pulverizing a pulverized raw material by a vertical pulverizer, and a method for operating a pulverizing system used in the method.
Background
Conventionally, as one of pulverizers for drying and pulverizing a pulverized raw material, a vertical pulverizer has been known. Examples of the raw materials for pulverization include cement raw materials and calcium carbonate. Patent documents 1 and 2 disclose a pulverizing system including such a vertical pulverizer.
Patent document 1 discloses a closed-circuit pulverizing system. The pulverizing system includes a vertical pulverizer having a classifier built therein. When the pulverized raw material is pulverized by a pulverizer, a pulverized product including coarse powder and fine powder is produced. The coarse powder is once discharged from the pulverizer, and then supplied again to the pulverizer for re-pulverization. The fine powder is passed through a classifier together with the gas rising in the pulverizer, and classified into fine powder and powder other than the fine powder in the classifier. The fine powder is discharged from the pulverizer together with the gas, collected by the dust collector, and recovered as a product. The gas separated from the fine powder in the dust collector is returned to the pulverizer.
The pulverizing system of patent document 2 includes a classifier independent of a vertical pulverizer. The fine powder in the pulverized material of the pulverizer is discharged from the pulverizer together with the gas extracted from the pulverizer, 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 pulverizer, and the fine powder is conveyed to the classifier by the conveyor. The coarse powder in the crushed material of the crusher is conveyed to the classifier by the conveyor. The pulverized material fed to the classifier is classified into fine powder and powder other than the fine powder, the fine powder is recovered as a product by a dust collector of a subsequent stage, and the powder other than the fine powder is returned to the pulverizer. In the pulverizing system of patent document 2, since the circulation system of the pulverized material of the pulverizer is independent of the circulation system of the gas of the pulverizer, the extraction amount from the pulverizer and the classification air volume of the classifier can be adjusted independently.
Patent document 1: japanese patent laid-open No. 9-117685
Patent document 2: japanese patent application laid-open No. 2018-202347
Disclosure of Invention
The present application has been developed in order to further develop the application described in patent document 2, and an object thereof is to provide the following technique: fine powder (powder) of arbitrarily adjusted powder degree is produced by a closed-circuit pulverizing system including a vertical pulverizer.
A method of operating a pulverizing system according to an aspect of the present application is a method of operating a pulverizing system including:
a vertical pulverizer that pulverizes a pulverized raw material;
a pulverized material circulation path for moving pulverized material from a discharge port of the vertical pulverizer to a supply port;
a classifier which is provided in the pulverized material circulation path and separates the pulverized material into fine powder as a product and coarse powder returned to the vertical pulverizer;
a catcher for recovering the fine powder;
the air pumping path is connected to the upper part of the vertical crusher;
an air extraction fan for extracting air from the vertical pulverizer to the air extraction path at a set air extraction volume; and
a dust collector for separating the fine powder from the suction air of the vertical pulverizer and conveying the fine powder to the pulverized material circulation path,
the above-mentioned operation method of the pulverizing system is characterized in that,
a correlation between the air extraction volume from the vertical mill and the powder degree of the fine powder to be collected is obtained, and the air extraction volume of a desired powder degree is estimated based on the correlation, and is used as the set air extraction volume.
The method for producing a powder according to one aspect of the present application includes the steps of: the method comprises the steps of feeding a crushed raw material to a vertical crusher to crush the crushed raw material, exhausting the crushed raw material from the vertical crusher at a set exhaust air volume to take out micro powder in the crushed material in a manner of riding an air flow, separating the micro powder from the air flow to convey the micro powder to a classifier by a conveyor, conveying the rest of the crushed material to the classifier by the conveyor, classifying the crushed material into fine powder and coarse powder according to a set particle size by the classifier, conveying the fine powder from the classifier to a catcher by the air flow to recover the fine powder as a product by the catcher, and returning the coarse powder from the classifier to the vertical crusher to be crushed again. Further, in the method for producing powder, a correlation between the air extraction volume from the vertical mill and the powder level of the fine powder to be collected is obtained, and the air extraction volume at which a desired powder level is obtained is estimated based on the correlation, and is used as the set air extraction volume.
According to the above-described method of operating the pulverizing system and method of producing powder, a fine powder (powder) having an arbitrary powder degree can be obtained by varying the set air suction volume. That is, the powder degree of the fine powder to be obtained can be changed to obtain a powder product corresponding to the purpose of use. Thus, the quality of the powder product can be improved.
According to the present application, the following technique can be provided: fine powder (powder) of arbitrarily adjusted powder degree is produced by a closed-circuit pulverizing system including a vertical pulverizer.
Drawings
Fig. 1 is a diagram showing an overall configuration of a pulverizing system according to an embodiment of the present application.
Fig. 2 is a diagram showing a configuration of a second experimental apparatus simulating a conventional pulverizing system.
Fig. 3 is a graph showing a correlation between the amount of air taken out from the vertical mill and the powder degree of the collected fine powder.
Fig. 4 is a graph showing a characteristic curve of the unit power consumption of the vertical crusher with respect to the amount of air taken out from the vertical crusher.
Detailed Description
Next, embodiments of the present application will be described with reference to the drawings. Fig. 1 is a diagram showing an overall configuration of a pulverizing system 1 according to an embodiment of the present application.
The closed-circuit pulverizing system 1 shown in fig. 1 includes a vertical pulverizer 2 (hereinafter, simply referred to as "pulverizer 2"), a pulverized material circulation system 3 connected to the pulverizer 2, and a gas circulation system 4 connected to the pulverizer 2.
[ vertical pulverizer 2 ]
The pulverizer 2 includes a housing 21, and the housing 21 forms a pulverizing chamber 20 for pulverizing a pulverized raw material. The housing 21 is provided with a rotary table 22 that rotates around a vertical rotation axis, and a plurality of pulverizing rollers 23, and the plurality of pulverizing rollers 23 are pressed against the rotary table 22 by a pressing mechanism, not shown, to perform driven rotation. Below the housing 21, a mill motor 24 as a rotation drive source of the rotary table 22 and a reduction mechanism 25 for transmitting rotation power of the mill motor 24 to the rotary table 22 are provided. The pulverizer 2 is not built-in with a classifier.
A supply port 26 is provided in an upper portion of the housing 21. The pulverized material is introduced to the upper surface of the turntable 22 through the supply port 26. Further, an air suction port 27 is provided above the turntable 22 and above the housing 21. The fine powder generated by the pulverization of the pulverized material is discharged by the air flow blown up through the air suction port 27. A discharge port 28 is provided below the rotary table 22. The crushed material overflowed from the outer periphery of the rotary table 22 is discharged to the outside of the crusher 2 through the discharge port 28. Further, a hot air outlet 29 is provided around the outer periphery of the turntable 22. Hot air is blown upward from the hot air blowing port 29 into the pulverizing chamber 20.
[ pulverized material circulation System 3 ]
The pulverized material circulation system 3 is configured to separate fine powder as a product from pulverized material discharged from the discharge port 28 of the pulverizer 2, and return the pulverized material from which the fine powder was separated to the pulverizer 2. The fine powder separated by the pulverized material circulating system 3 is recovered as a product.
The pulverized material circulation system 3 has a pulverized material circulation path 30 through which the pulverized material discharged from the pulverizer 2 moves from the discharge port 28 of the pulverizer 2 to the supply port 26. The crushed material circulation path 30 is provided with a classifier 7. 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 conveyor 31 that conveys 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 of the present embodiment is a bucket elevator including a plurality of buckets, not shown.
The discharge port 28 of the pulverizer 2 is connected to the first inlet 31a of the conveyor 31 via a passage 30 a. The conveyor 31 conveys the crushed material charged through a first inlet 31a and a second inlet 31b described later upward, and discharges the crushed material from an outlet 31 c. The outlet 31c of the conveyor 31 is connected to the crushed material inlet 71 of the classifier 7 via the passage 30 b. A distribution damper, not shown, may be provided in the passage 30b connecting the conveyor 31 and the classifier 7. Further, a part of the crushed material may be directly fed to the feed port 26 of the crusher 2 without passing through the classifier 7 by the distribution damper.
The classifier 7 classifies the supplied pulverized material into fine powder and coarse powder according to a set particle size. Further, the set particle diameter of the "fine powder" is determined according to the particle diameter of the product to be recovered. The "coarse powder" here means a pulverized product having a larger particle diameter than the fine powder among the pulverized products supplied to the classifier 7. In the present embodiment, an air-flow classifier is used as the classifier 7. However, the classifier 7 is not limited to the air-flow classifier as long as the pulverized product can be classified into fine powder and powder other than fine powder 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 pulverizer 2 via the passage 30 c.
The pulverized material classified into fine powder by the classifier 7 is discharged from the exhaust port 73 while being entrained with the air flow. The exhaust port 73 is connected to the inlet of the catcher 6 via the passage 64. The exhaust passage 65 of the catcher 6 is provided with a classifying fan 66. The exhaust air amount of the classifying fan 66 is adjusted so as to be a predetermined classifying air amount F2.
The collector 6 collects fine powder associated with the gas discharged from the classifier 7, and separates the fine powder from the gas. In the present embodiment, a bag filter is used as the collector 6. However, the collector 6 is not limited to a bag filter, as long as it can collect fine powder accompanied by gas.
[ gas circulation System 4 ]
The gas circulation system 4 is configured to separate fine powder from exhaust gas of the pulverizer 2 and return the gas from which the fine powder is separated to the pulverizer 2 as hot air.
The gas circulation system 4 has a gas circulation path 40, and the gas circulation path 40 allows the gas extracted from the pulverizer 2 to flow from the extraction opening 27 of the pulverizer 2 to the hot air inlet 29 a. The gas circulation path 40 is provided with a dust collector 41 for separating fine powder from the suction air from the pulverizer 2, a suction fan 42, and a hot air supply source 43 for supplying hot air to the gas circulation path 40. The exhaust amount of the exhaust fan 42 is adjusted so as to be the exhaust air amount F1.
The suction port 27 of the pulverizer 2 is connected to an inlet of the dust collector 41 via a suction passage 40 a. The outlet of the dust collector 41 is connected to the hot air inlet 29a of the pulverizer 2 via a passage 40 b. The hot air supply source 43 is connected to the passage 40 b.
The dust collector 41 separates the fine powder from the suction air from the pulverizer 2 (hereinafter referred to as "mill exhaust"). In the present embodiment, as the dust collector 41, a cyclone dust collector that uses the suction action of the suction fan 42 is used. However, the dust collector 41 is not limited to the cyclone dust collector as long as the fine powder can be separated from the mill exhaust gas.
The fine powder outlet of the dust collector 41 is connected to the second inlet 31b of the conveyor 31 via the fine powder conveying path 88. The fine powder separated from the mill exhaust gas by the dust collector 41 is conveyed to the conveyor 31 by the conveying path 88.
A passage 84 for conveying the mill exhaust gas from the passage 40b to the classifier 7 is connected to the passage 40b connected to the outlet of the dust collector 41 on the downstream side of the exhaust gas flow of the mill with respect to the suction fan 42. The flow rate adjusting device 85 is provided in the passage 84, and the flow rate adjusting device 85 adjusts the flow rate of the mill exhaust gas flowing to the classifier 7. By changing the opening degree of the flow rate adjustment 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 pulverizer 2 can be adjusted. The flow rate adjusting device 85 may be at least one of a damper, a flow rate adjusting valve, and a fan, for example, regardless of the form of the mechanism 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 generating furnace that generates hot air at a desired temperature. The hot air supplied from the hot air supply source 43 to the air circulation path 40 is supplied to the hot air inlet 29a of the pulverizer 2 through the passage 40b together with the mill exhaust gas. However, the hot air supply source 43 is not limited to the hot air generating furnace, and for example, when a source of high-temperature gas such as a baking furnace (cement baking furnace) is present around the crusher 2, the source of high-temperature gas may be used as the hot air supply source 43.
[ method for producing powder by the pulverizing System 1]
Here, a method of operating the pulverizing system 1 having the above-described configuration and a method of manufacturing powder using the pulverizing system 1 will be described. In the pulverizer 2, the inside of the pulverizing chamber 20 including the rotary table 22 and the pulverizing rollers 23 is preheated by hot air blown out from the hot air blowing port 29. Further, the rotary table 22 is driven to rotate by the mill motor 24, and the peripheral surface is driven to rotate by a plurality of pulverizing rollers 23 pressed against the pulverizing surface (upper surface) of the rotary table 22. The pulverized material is supplied to the rotary table 22 rotated in this manner through the supply port 26. The pulverized raw material is pulverized between the rotary table 22 and the pulverizing roller 23. Coarse powder in the pulverized material overflows from the periphery of the rotary table 22 and is discharged to the outside through the discharge port 28. The fine powder in the pulverized material is discharged from the air suction port 27 while riding on the blown air flow.
The mill exhaust gas from the exhaust port 27 of the pulverizer 2 flows into the dust collector 41. In the dust collector 41, fine powder associated with the mill exhaust gas is separated from the mill exhaust gas. The separated fine powder is conveyed to the second inlet 31b of the conveyor 31 through the conveying path 88, and is merged with the flow of the pulverized material in the pulverized material circulating system 3.
On the other hand, the mill exhaust gas from which fine powder is separated by the dust collector 41 is discharged from the dust collector 41, is sucked by the suction fan 42, and is sent to the downstream passage 40b of the gas circulation system 4. Here, the opening degree of the flow rate adjusting device 85 is adjusted so that the flow rate of the mill exhaust gas flowing into the passage 40b by the suction action of the suction fan 42 is balanced with the flow rate of the mill exhaust gas returned to the pulverizer 2. The hot air supplied from the hot air supply source 43 to the passage 40b flows into the pulverizer 2 together with the mill exhaust gas, and is blown out 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 material is classified, and the fine powder is separated from the pulverized material. The pulverized material from which the fine powder has been separated by the classifier 7 is discharged from the classifier 7, is conveyed to the supply port 26 of the pulverizer 2 through the passage 30c, and is pulverized again by the pulverizer 2. The fine powder separated from the pulverized material by the classifier 7 is discharged from the exhaust port 73 of the classifier 7 together with the gas, and is transported by the gas flow to the collector 6 through the passage 64. In the catcher 6, the fine powder is caught. The fine powder is recovered as a product, for example, in a bag. On the other hand, the gas separated from the fine powder by the catcher 6 flows out to the exhaust passage 65 and is released to the atmosphere.
[ adjustment of powder degree ]
As described above, the degree of powder (the degree of fineness of particles) of the fine powder recovered as a product is one of important factors indicating the quality of the fine powder. In the pulverizing system 1 having the above-described configuration, the powder degree of the fine powder to be obtained can be changed by adjusting the air suction amount F1. In order to verify that the powder fineness of the fine powder can be adjusted by adjusting the air suction amount F1, the following verification experiment was performed.
In the verification experiment, a first experimental apparatus for simulating the pulverizing system 1 of the present embodiment and a second experimental apparatus 101 for simulating the conventional pulverizing system were used (see fig. 2).
The first experimental apparatus simulates the pulverizing system 1 shown in fig. 1, and detailed description thereof is omitted. Experiments of examples 1 to 4 were performed using a first experimental set-up. The experimental conditions of examples 1 to 4 and comparative example 1 are shown in table 1. In examples 1 to 4, the classification air volume F2 was set at 15[ m ] 3 /min]Is kept constant. In example 1, the air volume F1 was 0[m 3 /min]In example 2, the air volume F1 was 3[m 3 /min]In example 3, the air volume F1 was 6[m 3 /min]In example 4, the air volume F1 was 9[m 3 /min]. The air extraction air volume F1 is the air extraction air volume of the air extraction fan 42, and the classification air volume F2 is the air extraction air volume of the classification fan 66.
Fig. 2 is a diagram showing the structure of the second experimental device 101. The second experimental device 101 includes a vertical crusher 102, a collector 106 connected to an exhaust port 127 of the crusher 102, and a classifying fan 166 for sucking the exhaust gas of the crusher 102 into the collector 106. The pulverizer 102 includes: the grinding apparatus includes a housing 121 forming a grinding chamber 120, a rotary table 122 rotating about a vertical rotation axis, a plurality of grinding rollers 123 driven to rotate by being pressed against the rotary table 122 by a pressing mechanism, not shown, a mill motor 124 as a rotation driving source of the rotary table 122, a speed reducing mechanism 125 transmitting rotation power of the mill motor 124 to the rotary table 122, and a classifier 107 provided above the grinding rollers 123 in the housing 121.
In the pulverizer 102, the pulverized material supplied onto the rotating rotary table 122 is pulverized between the rotary table 22 and the pulverizing roller 23 while being dried by hot air. The fine powder in the pulverized material is conveyed to the classifier 107 by the air flow blown from below, and classified into fine powder and powder other than fine powder by the classifier 107. The fine powder is discharged from the exhaust port 127 while being entrained with the air flow, and is collected by the collector 106. The fine powder other than the fine powder classified by the classifier 107 and the coarse powder overflowed from the periphery of the rotary table 122 are once discharged to the outside of the machine, and supplied to the pulverizer 102 again together with the new pulverized material.
The experiment of comparative example 1 was performed using the second experimental device 101 having the above-described structure. In comparative example 1, the classification air volume F2 was set at 15[ m ] 3 /min]Is kept constant. The classification air volume F2 is the air volume of the classification fan 166. In the second experimental device 101, since the air extraction volume (air discharge volume) from the pulverizer 102 is directly affected by the classification air volume F2, it is difficult to adjust only the air extraction volume.
TABLE 1
< experimental conditions >
| Example 1 | Example 2 | Example 3 | Example 4 | Comparative example 1 | |
| Experimental device | First one | First one | First one | First one | Second one |
| Air extraction volume F1 m 3 /min] | 0 | 3 | 6 | 9 | |
| Graded air volume F2 m 3 /min] | 15 | 15 | 15 | 15 | 15 |
In the experiments of examples 1 to 4 and comparative example 1, the pulverized raw materials were charged into a mill of an experimental apparatus, and the fine powder was recovered. For the collected fine powder sample, a specific surface area test and a mesh screen test were performed based on JIS R5201 (physical test method for cement) in order to determine the powder degree. In the specific surface area test, a specific surface area tester (Blaine air permeation measurement device) was used to measure the Blaine specific surface area [ cm ] of the sample 2 /g]. In the mesh screen test, a test sieve having a mesh opening of 45 μm was used to sieve the sample, and the amount of residue on the sieve was weighed to calculate the amount of residue [%](hereinafter, the content of particles having a particle diameter of 45 μm or more is referred to as "45. Mu.R").
Fig. 3 is a graph showing a correlation between the air suction amount F1 from the pulverizer 2 and the powder degree of the collected fine powder. The vertical axis of the graph represents the specific surface area [ cm ] 2 /g]The horizontal axis represents 45. Mu.R [%]The results of the powderization tests of the fine powders obtained in examples 1 to 4 and comparative example 1 are also shown. In examples 1 to 4 and comparative example 1, the specific surface area was decreased with an increase in the value of 45 μr at a constant air suction volume F1. In addition, at a constant 45 μr, the specific surface area becomes smaller as the air volume F1 of the air suction becomes larger.
The value of the specific surface area is affected by the amount of fine powder in the fine powder. From the result that the specific surface area becomes smaller as the air extraction air volume F1 becomes larger when the 45 μr is a constant value, it is found that the amount of fine powder becomes smaller as the air extraction air volume F1 becomes larger, and a clear powder structure with a narrow distribution width is obtained. In other words, it is known that the powder degree (specific surface area) of the fine powder can be adjusted by adjusting the air suction amount F1.
Further, the unit power consumption (electric power consumption rate) consumed for the production of the fine powder was measured for examples 1 to 4 and comparative example 1. The unit power consumption of the mill motor 24, 124 was measured as the unit power consumption. The unit power consumption of the mill motor 24, 124 accounts for a majority of the unit power consumption consumed in the manufacture of the fine powder.
Fig. 4 is a graph showing a characteristic curve of the unit power consumption of the pulverizer 2 with respect to the air suction amount F1 from the pulverizer 2, which is related to the production of the fine powder in examples 1 to 4 and comparative example 1. The vertical axis of the graph represents the unit power consumption [ kWh/t (DB) of comparative example 1]The unit power consumption [ kWh/t (DB) of examples 1 to 4 when taken as 100%]The vertical axis represents the air extraction volume F1[ m ] 3 /min]。
The unit power consumption of each of examples 1 to 4 was lower than that of comparative example 1. In addition, if the air volume F1 of the air extraction is less than about 4.5m 3 With an increase in the air extraction air volume F1, the unit power consumption gradually decreases, and if the air extraction air volume F1 is about 4.5m 3 With the increase of the air extraction amount F1, the unit power consumption gradually increases. Especially when the air suction quantity F1 is about 2-6 m 3 In the range of/min, the unit power consumption was reduced by about 30% as compared with the comparative example, and the power reduction effect was remarkable. This is presumably because the extraction of the fine powder portion from the pulverizer 2 together with the extraction of the air suppresses the excessive pulverization, and therefore the power consumption per unit is reduced. From the viewpoint of such reduction in unit power consumption, a preferable range is apparent as the air extraction volume F1.
From the results of the above-described verification experiments, it was verified that the powder degree (specific surface area) of the fine powder can be adjusted by adjusting the air volume F1 of the air suction from the pulverizer 2. In addition, it was verified that by adjusting the air volume F1 of the air suction from the pulverizer 2, the reduction of the unit power consumption of the mill motor 24 due to the prevention of the over-pulverization can be achieved.
In the operation method of the pulverizing system 1 of the present embodiment, the powder degree of the fine powder is adjusted by using the verified principle. That is, the operation method of the pulverizing system 1 according to the present embodiment is an operation method of a pulverizing system including: a pulverizer 2 that pulverizes a pulverized raw material; a pulverized material circulation path 30 through which pulverized material moves from the discharge port 28 of the pulverizer 2 to the supply port 26; a classifier 7 provided in the pulverized material circulation path 30 and dividing the pulverized material into fine powder as a product and coarse powder returned to the pulverizer 2; a catcher 6 for recovering the fine powder; a gas extraction path 40a connected to the upper part of the pulverizer 2; an air extraction fan 42 for extracting air from the pulverizer 2 to the air extraction path 40a at a set air extraction volume; and a dust collector 41 that separates the fine powder from the air suction of the pulverizer 2 and conveys the fine powder to the pulverized material circulation path 30, wherein a correlation between the air suction volume of the pulverizer 2 and the powder degree of the recovered fine powder (see fig. 3) is obtained, and the air suction volume F1 is used as a set air suction volume by estimating the air suction volume that can obtain a desired powder degree based on the correlation.
The method for producing powder using the pulverizing system 1 of the present embodiment includes the following steps: the raw materials to be crushed are crushed by the crusher 2, the fine powder in the crushed material is carried out by the suction air from the crusher 2 in a way of taking in an air current by setting the air suction air volume, the fine powder is separated from the suction air of the crusher 2 and is conveyed to the classifier 7, the rest of the crushed material is conveyed to the classifier 7 from the crusher 2, the crushed material is classified into fine powder and coarse powder according to the set particle size by the classifier 7, the fine powder is recovered as a product, and the coarse powder is returned from the classifier 7 to the crusher 2 and is crushed again. Further, a correlation between the air extraction volume of the pulverizer 2 and the powder degree of the collected fine powder is obtained (see fig. 3), and the air extraction volume at which the desired powder degree is obtained is estimated based on the correlation, and the air extraction volume is used as the set air extraction volume.
According to the above method for producing powder, the set air volume of the air suction is changed, whereby fine powder (powder) having an arbitrary powder degree can be obtained. That is, the powder quality of the obtained fine powder can be changed to obtain a powder product according to the purpose of use. Thus, the quality of the powder product can be improved.
In the method of operating the pulverizing system 1 and the method of manufacturing powder according to the present embodiment, a characteristic curve (see fig. 4) of the unit power consumption of the pulverizer 2 with respect to the air extraction volume is obtained, and the air extraction volume with the smallest unit power consumption among the air extraction volumes at which a desired degree of powder is obtained is used as the set air extraction volume based on the characteristic curve.
This can improve the quality of the fine powder (powder) and reduce the unit power consumption consumed for producing the fine powder (powder).
Hereinafter, an application example of the method for producing powder according to the present embodiment will be described.
When the pulverized raw material is a cement raw material of a cement type containing a mixture of a large amount of limestone or the like, since limestone is softer than clinker, fine powder tends to be generated easily, and the specific surface area of fine powder tends to be higher than a value defined as a cement raw material. In this case, by increasing the air suction volume F1, the value of the specific surface area of the fine powder can be reduced to within a predetermined value while maintaining the 45 μr of the fine powder at the predetermined value. This can improve the quality of the cement raw material.
In addition, in the case where the pulverized raw material is a cement raw material of a cement variety (Portland cement or the like) having a relatively small mixture of limestone or the like, the specific surface area of the fine powder tends to be lower than a value defined as the cement raw material. In this case, by reducing the air suction volume F1, the value of the specific surface area of the fine powder can be increased to be within a predetermined value while maintaining the 45 μr of the fine powder at the predetermined value. This can improve the quality of the cement raw material.
In the above, the air suction volume F1 is set to a range in which the specific surface area of the fine powder is set to a predetermined value. Therefore, if the air extraction air volume with the smallest unit power consumption out of the air extraction air volumes F1 that can obtain the desired powder degree is used by using the characteristic curve of the unit power consumption with respect to the air extraction air volume F1 (see fig. 4), the reduction of the unit power consumption can be achieved in addition to the improvement of the quality of the cement raw material.
Description of the reference numerals
1 … comminution system; 2 … vertical pulverizer; 3 … crushed material circulation system; 4 … gas circulation system; 6 … catcher; 7 … classifier; 20 … pulverizing chamber; 21 … shell; 22 … rotary table; 23 … pulverizing rolls; 24 … mill motor; 25 … reduction mechanism; 26 … supply port; 27 … exhaust ports; 28 … outlet; 29 … hot air outlet; 29a … hot air inlet; 30 … crushed material circulation path; 30a, 30b, 30c … pathway; 31 … conveyor; 31a … first inlet; 31b … second inlet; 31c … outlet; 40 … gas circulation path; 40a … air pumping channel; 40b … pathway; 41 … dust collector; 42 … exhaust fan; 43 … hot air supply; 64 … passage; 65 … exhaust path; 66 … exhaust fan; 71 … crushed material inlet; 72 … outlet; 73 … exhaust port; 84 … pathway; 85 … flow regulating device; 88 … conveying path; 101 … second experimental set-up; 102 … vertical pulverizer; 106 … catcher; 107 … classifier; 120 … pulverizing chamber; 121 … casing; 122 … rotary table; 123 … pulverizing rolls; 124 … mill motor; 125 … reduction mechanism; 127 … exhaust ports; 166 … exhaust fan.
Claims (4)
1. A method for operating a pulverizing system, the pulverizing system comprising:
a vertical pulverizer that pulverizes a pulverized raw material;
a pulverized material circulation path for moving pulverized material from a discharge port of the vertical pulverizer to a supply port;
a classifier which is provided in the pulverized material circulation path and separates the pulverized material into fine powder as a product and coarse powder returned to the vertical pulverizer;
a catcher for recovering the fine powder;
the air pumping channel is connected to the upper part of the vertical crusher;
an air extraction fan for extracting air from the vertical pulverizer to the air extraction path by setting an air extraction volume; and
a dust collector for separating the fine powder from the suction air of the vertical pulverizer and feeding the fine powder to the pulverized material circulation path,
the method of operating the comminution system is characterized in that,
a correlation between the specific surface area of the fine powder to be collected and the residual amount of the sieve of a predetermined mesh when the air extraction volume from the vertical mill is changed is obtained, the air extraction volume in which the residual amount of the sieve is maintained at a predetermined value and the specific surface area is within a predetermined range is estimated based on the correlation, and the air extraction volume is used as the set air extraction volume.
2. A method of operating a comminution system as claimed in claim 1,
and determining a characteristic curve of the unit power consumption of the vertical crusher with respect to the air extraction volume, and based on the characteristic curve, maintaining the residual amount of the screen at a predetermined value and the air extraction volume with the minimum unit power consumption among the air extraction volumes with the specific surface area within a predetermined range as the set air extraction volume.
3. A method for manufacturing powder comprises the following steps:
pulverizing a pulverized material by a vertical pulverizer, extracting air from the vertical pulverizer at a set extraction air volume to thereby carry out fine powder in the pulverized material by a passenger air flow, separating the fine powder from the air extracted from the vertical pulverizer and conveying the fine powder to a classifier, conveying the remaining portion of the pulverized material from the vertical pulverizer to the classifier, classifying the pulverized material into fine powder and coarse powder according to a set particle size by the classifier, recovering the fine powder as a product, returning the coarse powder from the classifier to the vertical pulverizer and pulverizing again,
the method for producing the powder is characterized in that,
a correlation between the specific surface area of the fine powder to be collected and the residual amount of the sieve of a predetermined mesh when the air extraction volume from the vertical mill is changed is obtained, the air extraction volume in which the residual amount of the sieve is maintained at a predetermined value and the specific surface area is within a predetermined range is estimated based on the correlation, and the air extraction volume is used as the set air extraction volume.
4. The method for producing a powder according to claim 3, wherein,
and determining a characteristic curve of the unit power consumption of the vertical crusher with respect to the air extraction volume, and based on the characteristic curve, maintaining the residual amount of the screen at a predetermined value and the air extraction volume with the minimum unit power consumption among the air extraction volumes with the specific surface area within a predetermined range as the set air extraction volume.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
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| JP2019-125831 | 2019-07-05 | ||
| JP2019125831A JP7330786B2 (en) | 2019-07-05 | 2019-07-05 | Method for operating pulverization system and method for producing powder |
| PCT/JP2020/025852 WO2021006154A1 (en) | 2019-07-05 | 2020-07-01 | Method for operating pulverizing system, and method for manufacturing powder |
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| CN114007751A CN114007751A (en) | 2022-02-01 |
| CN114007751B true CN114007751B (en) | 2023-12-05 |
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| EP (1) | EP3995216A4 (en) |
| JP (1) | JP7330786B2 (en) |
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| CN113731561B (en) * | 2021-09-17 | 2023-01-24 | 湖南华杰机械设备有限公司 | Powder making process method and powder making system for desulfurized limestone |
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| JP2021010870A (en) | 2021-02-04 |
| EP3995216A4 (en) | 2024-03-27 |
| JP7330786B2 (en) | 2023-08-22 |
| EP3995216A1 (en) | 2022-05-11 |
| WO2021006154A1 (en) | 2021-01-14 |
| CN114007751A (en) | 2022-02-01 |
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