Method for grinding raw materials, method for producing coke, and apparatus for grinding raw materials

Abstract

Provided are a raw material pulverizing method, a coke manufacturing method, and a raw material pulverizing device capable of reducing variation in particle size of a pulverized raw material by setting a pulverizing strength based on prediction.SOLUTION: A raw material pulverizing method executed by a raw material pulverizing apparatus (14) in pulverizing equipment including a pulverizer (2) configured to pulverize a raw material, a conveyance line configured to convey the pulverized raw material, and a measuring device configured to measure a particle size of the conveyed raw material, the raw material pulverizing method including acquiring the measured particle size from the measuring device, predicting a time to change a pulverizing strength of the pulverizer based on the measured particle size and a predetermined target particle size range, and outputting a signal to change the pulverizing strength of the pulverizer at the predicted time.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for pulverizing raw materials, a method for producing coke, and a raw material pulverizing apparatus.

Background Art

[0002] For example, in the ironmaking process, the coke in the blast furnace needs to have high strength and a small variation in particle size (be uniform) in order to ensure the air permeability in the furnace. In order to produce uniform high-strength coke, it is necessary to increase the bulk density of the coal, which is the raw material, when heating and carbonizing the coal in the coke oven. Therefore, it is important to optimize the particle size of the coal charged into the coke oven.

[0003] Coarse coal with a large particle size cracks at the contact interface due to the difference in shrinkage rate with adjacent coal during heating in the coke oven, resulting in a decrease in strength. Also, fine coal with a small particle size scatters in the air when charged into the coke oven, reducing the bulk density of the coal charged into the coke oven. Therefore, in order to produce uniform high-strength coke, when pulverizing coal with a pulverizer, it is necessary to select pulverization conditions so that the particle size becomes the target particle size and reduce the variation in the particle size of the coal after the pulverization process.

[0004] For example, Patent Document 1 and Patent Document 2 disclose a method of measuring the particle size of coal after pulverization or the particle size of coal before and after pulverization, and changing the pulverization strength for each pulverizer based on the particle size change calculated from the measurement results so that the particle size of the coal after pulverization becomes the target particle size.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] However, in order to reduce the variation in particle size of crushed coal using methods such as those described in Patent Documents 1 and 2, the operator must constantly check the particle size of the coal after crushing or before and after crushing, which places an excessive workload on the operator. Furthermore, operating while frequently changing the crushing intensity places a heavy load on the crushing equipment. In addition, when changing the crushing intensity of a crusher, a predetermined time (for example, about 10 minutes) is required for the changed crushing intensity to be reflected after being instructed to the crusher. During this predetermined time, there is a problem that variations in the particle size of crushed coal may occur.

[0007] In view of these circumstances, the purpose of this disclosure is to provide a method for grinding raw materials, a method for producing coke, and a raw material grinding apparatus that can reduce variations in the particle size of the raw materials after grinding by setting the grinding intensity based on predictions. [Means for solving the problem]

[0008] (1) A method for grinding raw materials according to one embodiment of the present disclosure is: In a pulverizing facility having a pulverizer for pulverizing raw materials, a conveying line for transporting the pulverized raw materials, and a measuring device for measuring the particle size of the transported raw materials, a method for pulverizing raw materials performed by the raw material pulverizing device, To obtain the particle size measured from the measuring device, Based on the measured particle size and a predetermined target particle size range, predict the time to change the grinding intensity of the grinder. This includes outputting a signal to change the grinding intensity of the grinder at the predicted time.

[0009] (2) As one embodiment of the present disclosure, in (1), The measuring device continuously measures the particle size, Predicting the aforementioned time is done by calculating the measured change in particle size and then calculating the time at which the particle size falls outside the target particle size range from that change.

[0010] (3) As one embodiment of the present disclosure, in (2), The predicted time is corrected based on the granularity measured after the predicted time.

[0011] (4) In one embodiment of the present disclosure, in any of (1) to (3), Changing the crushing strength of the crusher includes changing the amount of coal transported into the crusher and changing the rotation speed of the hammers of the crusher.

[0012] (5) A method for producing coke according to one embodiment of the present disclosure is: The grinding strength of the grinder is changed by any of the grinding methods for the raw material (1) to (4), and if the raw material is coal, coke is produced by heating the coal ground by the grinder in a coke oven.

[0013] (6) A raw material grinding apparatus according to one embodiment of the present disclosure, A raw material grinding apparatus used in a grinding facility comprising a grinder for grinding raw materials, a conveying line for conveying the ground raw materials, and a measuring device for measuring the particle size of the conveyed raw materials, An acquisition unit that acquires the particle size measured from the aforementioned measuring device, A prediction unit predicts the time to change the grinding intensity of the grinder based on the measured particle size and a predetermined target particle size range. The system includes an output unit that outputs a signal to change the grinding intensity of the grinder at the predicted time. [Effects of the Invention]

[0014] According to this disclosure, it is possible to provide a method for grinding raw materials, a method for producing coke, and a raw material grinding apparatus that can reduce variations in the particle size of the raw materials after grinding by setting the grinding intensity based on predictions. [Brief explanation of the drawing]

[0015] [Figure 1]FIG. 1 is a diagram showing the overall configuration of a raw material pulverizing facility. [Figure 2] FIG. 2 is a detailed view of a part of the pulverizing facility of FIG. 1. [Figure 3] FIG. 3 is a diagram showing a configuration example of a raw material pulverizing apparatus according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a flowchart exemplifying the processing of a raw material pulverizing method according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram exemplifying time-series data of the proportion of coal coarse particles of 6 mm or more when the particle size is continuously measured. [Figure 6] FIG. 6 is a diagram showing an example in which the change in particle size is calculated from the time-series data of FIG. 5.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, a raw material pulverizing method, a coke manufacturing method, and a raw material pulverizing apparatus 14 according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 shows the overall configuration of a raw material pulverizing facility. FIG. 2 is a detailed view of a part 10 of the pulverizing facility of FIG. 1 and includes a measuring device 13 and a raw material pulverizing apparatus 14. FIG. 3 is a block diagram showing a configuration example of the raw material pulverizing apparatus 14. The raw material pulverizing apparatus 14 is used in a pulverizing facility having a pulverizer 2 for pulverizing a raw material, a conveyance line for conveying the pulverized raw material, and a measuring device 13 for measuring the particle size of the conveyed raw material, and sets the pulverizing strength based on a prediction as described below.

[0017] The raw material crushing equipment shown in Figure 1 represents a coal crushing processing line for a coke oven. In this embodiment, the raw material is coal. Here, the raw material is not limited to coal, as long as it is crushed to have little variation in particle size. Coal stored in yard 1 for each type is transported to crusher 2 for each type, crushed so that the particle size falls within the target particle size range 101 (see Figure 5), and stored in blending tank 4. Here, particle size is the ratio of particle sizes within a predetermined range (e.g., 6 mm or larger) (see Figure 5). The target particle size range 101 is the range that the particle size of the crushed coal 12 must satisfy in order to uniformly produce high-strength coke, and is determined according to the quality required for the coke to be produced. In the example in Figure 1, three crushers 2 are shown, but one or more are sufficient, and the number of crushers 2 is not limited to a specific number. Coal is transported to each crusher 2, and the crusher 2 crushes the coal according to the signal (control signal) from the raw material crushing device 14. The control signal includes an instruction to change the crushing intensity of the crusher 2. Changing the crushing intensity of the crusher 2 includes changing the amount of coal being transported into the crusher 2 and changing the rotation speed of the hammers of the crusher 2. In addition, a measuring device 13 for measuring the particle size of the crushed coal 12 is provided, for example, above the belt conveyor 11 (part of the transport line) on the exit side of the crusher 2. The measuring device 13 may continuously measure the particle size at a specific position 3 set on the belt conveyor 11 on the exit side of the crusher 2. Coal stored in the mixing tank 4 is transported to the coke oven 5, heated, and carbonized to produce coke.

[0018] As shown in Figure 2, the crushed coal 12 is transported by a belt conveyor 11 to the mixing tank 4. The measuring device 13 measures the crushed coal 12. The measuring device 13 outputs the measurement result to the raw material crushing device 14. The measurement result is the particle size measured by the measuring device 13. In this embodiment, the measuring device 13 includes a camera and captures a two-dimensional image of the crushed coal 12 loaded on the belt conveyor 11. The measuring device 13 identifies the two-dimensional shape of the crushed coal 12 from the captured two-dimensional image and calculates the particle size using a known method (image processing). Image processing may include, for example, binarization and contour extraction.

[0019] As shown in Figure 3, the raw material grinding device 14 comprises an acquisition unit 15, a prediction unit 16, and an output unit 17. The acquisition unit 15 acquires the particle size measured from the measuring device 13. The prediction unit 16 predicts the time to change the grinding intensity of the grinder 2 based on the measured particle size and a predetermined target particle size range 101. Details of the time prediction will be described later. The output unit 17 outputs a signal to change the grinding intensity of the grinder 2 at the time predicted by the prediction unit 16. Here, the raw material grinding device 14 may be, for example, a computer as a hardware configuration. The computer may be a server computer or a portable computer such as a laptop or tablet. In this embodiment, the raw material grinding device 14 is a computer used in the raw material grinding equipment. Also in this embodiment, the target particle size range 101 is stored in the computer's storage device.

[0020] Figure 4 is a flowchart illustrating the processing method of grinding raw materials performed by a raw material grinding device 14 in a grinding facility that includes a grinder 2 for grinding raw materials, a conveying line for transporting the ground raw materials, and a measuring device 13 for measuring the particle size of the transported raw materials.

[0021] The acquisition unit 15 acquires a predetermined target granularity range 101 from, for example, a storage device (step S1).

[0022] Furthermore, the acquisition unit 15 acquires the particle size of the raw material measured from the measuring device 13 (step S2).

[0023] The prediction unit 16 predicts the time to change the grinding intensity of the pulverizer 2 based on the measured particle size and target particle size range 101 acquired by the acquisition unit 15 (step S3). In this embodiment, the time prediction is performed by calculating the change in the measured particle size (see Figure 5) and calculating (predicting) the time when the particle size will fall outside the target particle size range 101 from the change.

[0024] The prediction unit 16 returns to the process in step S2 if there is sufficient time until the predicted time (Yes in step S4). Sufficient time until the predicted time means, for example, that the time from the current time to the predicted time is a predetermined time (for example, 1 hour) or more. The acquisition unit 15 acquires the particle size of the raw material newly measured from the measuring device 13 (step S2). Then, the prediction unit 16 uses the newly measured particle size to predict the time to change the grinding strength of the pulverizer 2 (step S3). Step S3 from the second time onward corresponds to the process of correcting the predicted time. In other words, the predicted time is corrected based on the particle size measured after the prediction time. This correction of the time makes it possible to improve the accuracy of the prediction.

[0025] If the prediction unit 16 does not have enough time until the predicted time (No. in step S4), it proceeds to the process in step S5. Then, the output unit 17 outputs a signal to change the crushing intensity of the crusher 2 when the time predicted by the prediction unit 16 arrives (step S5). The output signal is, for example, a control signal for the crusher 2.

[0026] The effects of this disclosure will be described in detail below based on the examples, but this disclosure is not limited to these examples.

[0027] Figure 5 illustrates the time-series data of the proportion of coarse coal particles (6 mm or larger) when particle size is measured continuously. Here, coarse coal refers to coal with a large particle size, as described above. From Figure 5, it can be seen that the coal particle size after crushing changes moment by moment. This change is thought to be caused by changes in the properties of the coal, such as moisture content, before crushing, and by some of the coal with high moisture content adhering to the crushing equipment after crushing.

[0028] Figure 6 shows an example of calculating the change in particle size using the time-series data from Figure 5, and explains how to calculate the time when the particle size falls outside the target range. More specifically, Figure 6 shows the measurement results from "3:00" to "3:30" in Figure 5. The particle size was measured every minute by the measuring device 13, and the average particle size was obtained by averaging 10 consecutive points. A regression equation was then calculated from the average particle size value. As a result, the regression equation was y = 0.0766x + 5.9808, indicating that the particle size changes at a rate of 0.0766% per minute. Here, y is the percentage of coarse coal particles of 6 mm or more [%]. Also, x is the time elapsed from "3:00" [minutes]. According to the regression equation, the time when the target particle size limit 102, which is the upper limit of the target particle size range 101, is exceeded is predicted to be 79 minutes later, or "4:19". In this embodiment, the target particle size limit 102 is 12%. For example, in Figure 5, data exceeding the target granularity limit of 102 is shown shortly before "5:00".

[0029] Then, at the predicted time (4:19 in this example), taking into account operational conditions such as yield, the amount of coal being fed into the crusher 2 is changed or the rotation speed of the hammers of the crusher 2 is changed. This type of control prevents the particle size from falling outside the target particle size range 101, thereby reducing the variation in coal particle size after crushing. Furthermore, the raw material crushing device 14 may calculate the improved particle size value in relation to the amount of change in crushing intensity and further adjust the crushing intensity of the crusher 2 so that the particle size approaches the center of the target particle size range 101 (8% in the example in Figure 5).

[0030] Here, Figure 5 shows an example where particle size measurements were continued without changing the grinding intensity of the pulverizer 2. If the grinding method for the raw material described above is performed and the grinding intensity of the pulverizer 2 is changed at the predicted time of "4:19", it is considered that the particle size will change within the target particle size range 101 without reaching the target upper limit 102.

[0031] As described above, the raw material grinding method, coke manufacturing method, and raw material grinding apparatus 14 according to this embodiment can reduce variations in the particle size of the raw material after grinding by setting the grinding intensity based on prediction, thanks to the above configuration. Specifically, the raw material grinding method, coke manufacturing method, and raw material grinding apparatus 14 according to this embodiment pre-determine a target particle size range 101, predict the time when the particle size of the raw material after grinding will fall outside the target particle size range 101, and change the grinding intensity at the predicted time. This control reduces variations in the particle size of the raw material. Furthermore, since the time for changing the grinding intensity is determined in advance, the workload on the operator does not become excessive. In addition, since the grinding intensity only needs to be changed when it is predicted that the particle size of the raw material after grinding will fall outside the particle size range, a large load is not placed on the grinding equipment.

[0032] While embodiments of this disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art will find it easy to make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications or alterations are included within the scope of this disclosure. For example, the functions included in each component or process can be rearranged in a logically consistent manner, and multiple components or processes can be combined into one or divided. Embodiments relating to this disclosure can also be realized as programs executed by a processor in the device or as storage media recording such programs. These should also be understood to be included within the scope of this disclosure.

[0033] For example, coal does not need to be crushed according to its type. For example, coal may be blended before crushing, and the particle size of the blended coal after crushing may be continuously measured. Then, using the same method as in the above embodiment, the time to change the crushing intensity may be predicted, and the crushing intensity may be changed at the predicted time.

[0034] In the above embodiment, the crushed coal 12 was identified from a two-dimensional image captured by a camera. As another example, the measuring device 13 may be a laser rangefinder or the like, and three-dimensional measurement may be performed, the crushed coal 12 may be identified using the obtained three-dimensional data, and the particle size of the crushed coal 12 may be calculated.

[0035] Furthermore, the raw material grinding device 14 may not be a single device, but rather composed of multiple devices located in multiple locations that can send and receive data from each other via a network. In other words, multiple devices connected by a network may function as the raw material grinding device 14 as a whole. Therefore, for example, the raw material grinding device 14 may consist of a single computer as its hardware configuration, or it may consist of multiple computers connected by a network. When it consists of multiple computers, a shared memory accessible to each computer may be used to share data or programs. For example, the output unit 17 of the raw material grinding device 14 may be a single device (grinding intensity instruction device) that outputs an instruction signal (control signal) regarding grinding intensity to the grinder 2. In this case, the part of the raw material grinding device 14 other than the output unit 17 may be another device (grinding control device).

[0036] Furthermore, if the raw material grinding device 14 is configured with a computer, one or more programs used to control the operation of the raw material grinding device 14 may be stored in the computer's storage device (e.g., memory). When the programs stored in the storage device are read by the computer's processor, the processor may be made to function as an acquisition unit 15, a prediction unit 16, and an output unit 17. The computer may then execute the processing for the raw material grinding method. [Explanation of Symbols]

[0037] 1 yard 2. Crusher 3 Specific position 4 Mixing tank 5. Coke oven 10 Part of the crushing equipment 11 Belt conveyor 12. Crushed coal 13 Measuring devices 14. Grinding equipment for raw materials 15 Acquisition Department 16 Prediction Section 17 Output section 101 Target granularity range 102 Target granularity upper limit

Claims

1. In a pulverizing facility having a pulverizer for pulverizing raw materials, a conveying line for transporting the pulverized raw materials, and a measuring device for measuring the particle size of the transported raw materials, a method for pulverizing raw materials performed by the raw material pulverizing device, To obtain the particle size measured from the measuring device, Based on the measured particle size and a predetermined target particle size range, predict the time to change the grinding intensity of the grinder. This includes outputting a signal to change the grinding intensity of the grinder at the predicted time, The measuring device continuously measures the particle size, A method for grinding raw materials, wherein predicting the aforementioned time is performed by calculating the measured change in particle size and calculating the time at which the particle size falls outside the target particle size range from the change.

2. The method for grinding a raw material according to claim 1, wherein the predicted time is corrected based on the particle size measured after the predicted time.

3. The method for crushing a raw material according to claim 1 or 2, wherein changing the crushing strength of the crusher includes changing the amount of coal transported into the crusher and changing the rotation speed of the hammers of the crusher.

4. A method for producing coke, comprising changing the grinding strength of the grinder by the raw material grinding method described in claim 1 or 2, wherein the raw material is coal, and coke is produced by heating the coal ground by the grinder in a coke oven.

5. A raw material grinding device used in a grinding facility that includes a grinder for grinding raw materials, a conveying line for conveying the ground raw materials, and a measuring device for measuring the particle size of the conveyed raw materials, An acquisition unit that acquires the particle size measured from the aforementioned measuring device, A prediction unit predicts the time to change the grinding intensity of the grinder based on the measured particle size and a predetermined target particle size range. The system includes an output unit that outputs a signal to change the grinding intensity of the grinder at the predicted time, The measuring device continuously measures the particle size, The prediction unit predicts the time by calculating the measured change in particle size and calculating the time at which the particle size falls outside the target particle size range from the change, in a raw material grinding apparatus.

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