Method for pulverizing raw material, method for producing coke, and apparatus for pulverizing raw material

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 raw material pulverization method, a coke manufacturing method, and a raw material pulverization device. [Background technology]

[0002] For example, in the ironmaking process, the coke in the blast furnace must be high-strength and have small particle size variations (uniformity) to ensure good ventilation within the furnace. In order to produce uniform high-strength coke, the raw material coal must be heated and carbonized in the coke oven, and the bulk density of the coal charged into the coke oven must be increased. Therefore, it is important to optimize the particle size of the coal charged into the coke oven.

[0003] Coarse coal with large particle size undergoes cracking at the contact interface due to differences in contraction rates between adjacent coal particles during heating in a coke oven, reducing its strength. Furthermore, fine coal with small particle size floats in the air when charged into the coke oven, reducing the bulk density of the coal charged. Therefore, in order to produce uniform high-strength coke, it is necessary to select crushing conditions when crushing coal in a crusher to achieve the target particle size and reduce the variation in particle size of the coal after crushing.

[0004] For example, Patent Documents 1 and 2 disclose methods for measuring the particle size of coal after crushing or the particle size of coal before and after crushing, and changing the crushing intensity for each crusher based on the particle size change calculated from the measurement results, so that the particle size of the coal after crushing becomes a target particle size. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-16983 [Patent Document 2] Japanese Patent Application Publication No. 2018-51425 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in order to reduce variation in the particle size of the coal after crushing using the methods described in Patent Documents 1 and 2, an operator must constantly check the particle size of the coal after crushing or the particle size of the coal before and after crushing, which places an excessive workload on the operator. Furthermore, frequently changing the crushing strength during operation places a heavy load on the crushing equipment. Furthermore, changing the crushing strength of a crusher requires a certain time (e.g., about 10 minutes) from the time the changed crushing strength is instructed to the crusher until it is reflected. During this certain time, there is a problem that variation occurs in the particle size of the coal after crushing.

[0007] The purpose of the present disclosure, made in consideration of the above circumstances, is to provide a raw material crushing method, a coke manufacturing method, and a raw material crushing device that can reduce the variation in particle size of the raw material after crushing by setting the crushing intensity based on predictions. [Means for solving the problem]

[0008] (1) A method for grinding a raw material according to an embodiment of the present disclosure includes: A method for grinding raw materials, which is carried out by a grinding device for raw materials in a grinding facility having 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, comprising: acquiring the measured particle size from the measurement device; predicting a time to change the grinding intensity of the grinder based on the measured particle size and a predetermined target particle size range; and outputting a signal to change the crushing intensity of the crusher at the predicted time.

[0009] (2) As one embodiment of the present disclosure, in (1), the measuring device continuously measures the particle size; The time is predicted by calculating a transition of the measured granularity and calculating the time at which the granularity will fall outside the target granularity range from the transition.

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

[0011] (4) As an embodiment of the present disclosure, in any one of (1) to (3), The change in the crushing strength of the crusher includes a change in the amount of coal fed into the crusher and a change in the rotation speed of the hammers of the crusher.

[0012] (5) A method for producing coke according to one embodiment of the present disclosure includes: The crushing strength of the crusher is changed by any one of the raw material crushing methods (1) to (4), the raw material is coal, and the coal crushed by the crusher is heated in a coke oven to produce coke.

[0013] (6) A raw material grinding device according to an embodiment of the present disclosure includes: A raw material grinding device used in a grinding facility having 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 by the measurement device; a prediction unit that predicts a time to change the crushing intensity of the crusher based on the measured particle size and a predetermined target particle size range; and an output unit that outputs a signal to change the crushing intensity of the crusher at the predicted time. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to provide a raw material crushing method, a coke manufacturing method, and a raw material crushing device that can reduce variation in particle size of the raw material after crushing by setting the crushing intensity based on prediction. [Brief explanation of the drawings]

[0015] [Figure 1]FIG. 1 is a diagram showing the overall configuration of a raw material crushing facility. [Figure 2] FIG. 2 is a detailed view of a portion of the grinding installation of FIG. [Figure 3] FIG. 3 is a diagram illustrating an example of the configuration of a raw material crushing device according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a flowchart illustrating the process of a raw material grinding method according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram illustrating time-series data of the proportion of coarse coal particles of 6 mm or more when particle size is measured continuously. [Figure 6] FIG. 6 is a diagram showing an example in which the transition of granularity is calculated using the time-series data of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a raw material pulverization method, a coke manufacturing method, and a raw material pulverization device 14 according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 shows the overall configuration of the raw material pulverization equipment. FIG. 2 is a detailed view of a portion 10 of the pulverization equipment of FIG. 1, including a measuring device 13 and the raw material pulverization device 14. FIG. 3 is a block diagram showing an example configuration of the raw material pulverization device 14. The raw material pulverization device 14 is used in a pulverization equipment having a pulverizer 2 that pulverizes the raw material, a conveying line that conveys the pulverized raw material, and a measuring device 13 that measures the particle size of the conveyed raw material, and sets the pulverization intensity based on prediction, as described below.

[0017] The raw material crushing equipment shown in FIG. 1 represents a coal crushing line for coke ovens. In this embodiment, the raw material is coal. The raw material is not limited to coal, as long as it can be crushed to minimize particle size variation. Coal stored in a yard 1 by brand is transported to a crusher 2 by brand, crushed to a particle size within a target particle size range 101 (see FIG. 5), and stored in a blending tank 4. Here, the particle size refers to the ratio of particle sizes within a predetermined range (e.g., 6 mm or more) (see FIG. 5). The target particle size range 101 is the range that the crushed coal 12 must satisfy in order to produce uniformly high-strength coke, and is determined based on the quality required for the coke to be produced. In the example shown in FIG. 1, three crushers 2 are shown, but the number of crushers 2 is not limited to a specific number; any number greater than one will suffice. Coal is transported to each crusher 2, and the crusher 2 crushes the coal in accordance with a signal (control signal) from a raw material crusher 14. The control signal includes an instruction to change the crushing strength of the pulverizer 2. Changing the crushing strength of the pulverizer 2 includes changing the amount of coal fed into the pulverizer 2 and changing the rotation speed of the hammers of the pulverizer 2. In addition, a measuring device 13 that measures the particle size of the pulverized coal 12 is provided, for example, above the belt conveyor 11 (part of the conveying line) on the outlet side of the pulverizer 2. The measuring device 13 may continuously measure the particle size at a specific position 3 set on the belt conveyor 11 on the outlet side of the pulverizer 2. The coal stored in the blending tank 4 is transported to the coke oven 5, where it is heated and carbonized to produce coke.

[0018] As shown in FIG. 2, the pulverized coal 12 is transported in the transport direction to the blending tank 4 by a belt conveyor 11. A measuring device 13 measures the pulverized coal 12. The measuring device 13 outputs the measurement results to a raw material pulverizer 14. The measurement results are particle sizes measured by the measuring device 13. In this embodiment, the measuring device 13 includes a camera and captures two-dimensional images of the pulverized coal 12 stacked on the belt conveyor 11. The measuring device 13 identifies the two-dimensional shape of the pulverized coal 12 from the captured two-dimensional image and calculates and obtains the particle size using a known method (image processing). The image processing may include, for example, binarization, contour extraction, and the like.

[0019] As shown in FIG. 3, the raw material crushing device 14 includes an acquisition unit 15, a prediction unit 16, and an output unit 17. The acquisition unit 15 acquires the particle size measured by the measuring device 13. The prediction unit 16 predicts the time to change the crushing strength of the crusher 2 based on the measured particle size and a predetermined target particle size range 101. The time prediction will be described in detail later. The output unit 17 outputs a signal to change the crushing strength of the crusher 2 at the time predicted by the prediction unit 16. Here, the raw material crushing device 14 may be configured as hardware, such as a computer. The computer may be a server computer or a portable computer such as a laptop or tablet. In this embodiment, the raw material crushing device 14 is a computer used in the raw material crushing equipment. In addition, in this embodiment, the target particle size range 101 is stored in the computer's storage device.

[0020] FIG. 4 is a flowchart illustrating the processing of a raw material grinding method performed by a raw material grinding device 14 in a grinding facility having a grinder 2 that grinds raw materials, a conveying line that conveys the ground raw materials, and a measuring device 13 that measures the particle size of the conveyed raw materials.

[0021] The acquiring 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 by the measuring device 13 (step S2).

[0023] The prediction unit 16 predicts the time to change the crushing intensity of the crusher 2 based on the measured particle size and the target particle size range 101 acquired by the acquisition unit 15 (step S3). Here, in this embodiment, the time prediction is performed by calculating the transition of the measured particle size (see FIG. 5) and calculating (predicting) the time when the transition will deviate from the target particle size range 101.

[0024] If there is sufficient time until the predicted time (Yes in step S4), the prediction unit 16 returns to the processing of step S2. For example, "there is sufficient time until the predicted time" may mean that the time from the current time to the predicted time is equal to or greater than a predetermined time (e.g., one hour). The acquisition unit 15 acquires the newly measured particle size of the raw material from the measurement device 13 (step S2). The prediction unit 16 then predicts the time to change the grinding intensity of the grinder 2 using the newly measured particle size (step S3). Step S3 from the second time onwards 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. This time correction can improve the accuracy of the prediction.

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

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

[0027] Figure 5 shows an example of time-series data on the proportion of coarse coal particles 6 mm or larger when particle size is measured continuously. Here, coarse coal refers to coal with large particle sizes, as described above. Figure 5 shows that the particle size of the coal after crushing changes from moment to moment. This change is thought to be caused by, for example, changes in the moisture content and other properties of the coal before crushing, or by some of the coal with high moisture content adhering to the crushing equipment during crushing.

[0028] FIG. 6 shows an example of particle size transitions calculated using the time-series data of FIG. 5 and explains how to calculate the time when particle size falls outside the target range. Specifically, FIG. 6 shows measurement results from 3:00 to 3:30 in FIG. 5. Particle size measurements were performed every minute using the measuring device 13. Ten consecutive measurements were averaged to determine the average particle size, and a regression equation was calculated from the average particle size value. The resulting regression equation was y = 0.0766x + 5.9808, indicating that particle size transitions at a rate of 0.0766% per minute. Here, y is the percentage [%] of coarse coal particles 6 mm or larger. Furthermore, x is the time [minutes] elapsed since 3:00. According to the regression equation, the time when the target particle size upper limit 102, which is the upper limit of the target particle size range 101, will be exceeded is predicted 79 minutes later, at 4:19. In this example, the target particle size upper limit 102 is 12%. For example, in FIG. 5, data exceeding the target granularity upper limit 102 is shown shortly before "5:00."

[0029] Then, at the predicted time (4:19 in this example), taking into account the operating conditions such as yield, the amount of coal fed into the pulverizer 2 or the rotation speed of the hammers of the pulverizer 2 is changed. By such control, the particle size is prevented from deviating from the target particle size range 101, thereby reducing the variation in the particle size of the coal after pulverization. Furthermore, the raw material pulverizer 14 may calculate the improved particle size value for the amount of change in the crushing strength, and further adjust the crushing strength of the pulverizer 2 so that the particle size approaches the center of the target particle size range 101 (8% in the example of FIG. 5).

[0030] 5 shows an example in which particle size measurement was continued without changing the crushing strength of the crusher 2. If the above-described raw material crushing method is carried out and the crushing strength of the crusher 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 particle size upper limit 102.

[0031] As described above, the raw material pulverization method, coke manufacturing method, and raw material pulverization device 14 according to the present embodiment can reduce the variation in particle size of the pulverized raw material by setting the pulverization intensity based on predictions. That is, the raw material pulverization method, coke manufacturing method, and raw material pulverization device 14 according to the present embodiment determine a target particle size range 101 in advance, predict the time when the particle size of the pulverized raw material will fall outside the target particle size range 101, and change the pulverization intensity at the predicted time. This control reduces the variation in particle size of the raw material. Furthermore, because the time to change the pulverization intensity is determined in advance, the operator's workload is not excessive. Furthermore, because the pulverization intensity needs to be changed only when the particle size of the pulverized raw material is predicted to fall outside the particle size range, the pulverization equipment is not heavily burdened.

[0032] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included within the scope of the present disclosure. For example, the functions included in each component or step can be rearranged so as not to cause logical inconsistencies, and multiple components or steps can be combined or divided into one. The embodiments of the present disclosure can also be realized as a program executed by a processor included in an apparatus or a storage medium on which a program is recorded. It should be understood that these are also included within the scope of the present disclosure.

[0033] For example, coal does not have to be crushed by brand. For example, coals may be blended before crushing, and the particle size of the blended coals after crushing may be continuously measured. Then, using the same method as in the above embodiment, the time to change the crushing strength may be predicted, and the crushing strength may be changed at the predicted time.

[0034] In the above embodiment, the pulverized coal 12 is 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, which performs three-dimensional measurement, and the obtained three-dimensional data may be used to identify the pulverized coal 12 and calculate the particle size of the pulverized coal 12.

[0035] Furthermore, the raw material crushing device 14 may not be a single device, but may be composed of multiple devices located in multiple locations and capable of transmitting and receiving data to and from each other via a network. In other words, multiple devices connected via a network may function as the raw material crushing device 14 as a whole. Therefore, for example, the raw material crushing device 14 may be composed of a single computer as a hardware configuration, or multiple computers connected via a network. When composed of multiple computers, a shared memory accessible by each computer may be used to share data or programs. For example, the output unit 17 of the raw material crushing device 14 may be a single device (crushing intensity instruction device) that outputs an instruction signal (control signal) regarding the crushing intensity to the crusher 2. In this case, the parts of the raw material crushing device 14 other than the output unit 17 may be separate devices (crushing control devices).

[0036] Furthermore, when the raw material crushing device 14 is configured by a computer, one or more programs used to control the operation of the raw material crushing device 14 may be stored in a storage device (e.g., memory) of the computer. When the program stored in the storage device is read by a processor included in the computer, the processor may function as the acquisition unit 15, the prediction unit 16, and the output unit 17. Then, the processing of the raw material crushing method may be executed by the computer. [Explanation of symbols]

[0037] 1 yard 2. Crusher 3 Specific position 4 Mixing tank 5. Coke oven 10 Part of the crushing equipment 11 Conveyor belt 12. Pulverized coal 13 Measuring equipment 14 Raw material crushing equipment 15 Acquisition Department 16 Prediction Department 17 Output section 101 Target particle size range 102 Target grain size upper limit

Claims

1. A method for grinding raw materials, which is carried out by a grinding device for raw materials in a grinding facility having 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, comprising: acquiring the measured particle size from the measurement device; predicting a time to change the grinding intensity of the grinder based on the measured particle size and a predetermined target particle size range; and outputting a signal to change the grinding intensity of the grinder at the predicted time.

2. the measuring device continuously measures the particle size; 2. The method for grinding raw material according to claim 1, wherein the time is predicted by calculating a transition of the measured particle size and calculating the time at which the particle size will fall outside the target particle size range from the transition.

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

4. The method for crushing a raw material according to claim 1 , wherein the change in the crushing strength of the crusher includes a change in the amount of coal fed into the crusher and a change in the rotation speed of a hammer of the crusher.

5. A method for producing coke, comprising: changing a crushing strength of the crusher by the method for crushing a raw material according to any one of claims 1 to 3; the raw material being coal; and heating the coal crushed by the crusher in a coke oven to produce coke.

6. A raw material grinding device used in a grinding facility having 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 by the measurement device; a prediction unit that predicts a time to change the crushing intensity of the crusher based on the measured particle size and a predetermined target particle size range; an output unit that outputs a signal to change the crushing strength of the crusher at the predicted time.

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