Method for adjusting the moisture content of raw materials, method for producing coke, and apparatus for adjusting the moisture content of raw materials

Abstract

A method for adjusting the moisture content of raw materials, a method for producing coke, and a device for adjusting the moisture content of raw materials are provided, which can be adjusted to an appropriate amount according to the particle size. [Solution] The method for adjusting the moisture content of raw materials is a method for adjusting the moisture content of raw materials performed by a raw material moisture content adjustment device (14) in a humidity control facility having a conveying line for conveying raw materials crushed by a pulverizer (2), a measuring device for measuring the particle size of the conveyed raw materials, and a humidity control device (4) for adjusting the humidity of the raw materials whose particle size has been measured, and includes obtaining the particle size measured from the measuring device and changing the target value of the raw material moisture content of the humidity control device based on the measured particle size.

Description

Technical Field

[0001] The present disclosure relates to a method for adjusting the raw material moisture content, a method for producing coke, and an apparatus for adjusting the raw material moisture content.

Background Art

[0002] For example, in the ironmaking process, the air permeability in the furnace is important. In order to ensure the air permeability, the coke in the blast furnace is required to be produced with little variation in quality and within the operating target range. Since the quality of coke depends on the quality of the coal as the raw material, the properties of the coal are made constant.

[0003] In order to produce high-quality coke, it is necessary to cause strong contact between coal particles when heating and carbonizing in a coke oven. Therefore, the coal particle size is adjusted to increase the bulk density. Here, in the conveying process before the carbonization process, fine particles containing moisture may be compacted to form pseudo-particles. In the carbonization process, if pseudo-particles or coarse particles with a large particle size are mixed in, cracks occur starting from the pseudo-particles or coarse particles due to the difference in heat capacity, resulting in a reduction in coke strength. Here, the particle size can be adjusted by crushing. Also, since pseudo-particles are formed when there are many fine particles and a large amount of moisture, formation can be suppressed by avoiding an excessive increase in the moisture content when there are many fine particles. In the coke production process, for example, a humidifying machine that adjusts the moisture content to a target value may be used.

[0004] Also, for example, Patent Document 1 discloses a method of pre-humidifying the coal with less occluded moisture when handling coal with a large amount of occluded moisture and coal with relatively less occluded moisture to make the moisture content of both coals the same as that of the coal with a large amount of occluded moisture. Also, for example, Patent Document 2 discloses a method that can suppress over-drying of coal even when restarting after stopping the normal humidifying operation.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2000-178562 [Patent Document 2] Japanese Patent Publication No. 2014-118465 [Overview of the project] [Problems that the invention aims to solve]

[0006] Considering factors such as dust generation, it is not possible to excessively reduce the moisture content of coal, and it is necessary to adjust the moisture content in accordance with changes in particle size. Patent documents 1 and 2 do not describe how to adjust the moisture content of coal when particle size changes during operation.

[0007] In view of these circumstances, the purpose of this disclosure is to provide a method for adjusting the moisture content of raw materials, a method for producing coke, and an apparatus for adjusting the moisture content of raw materials, which can be adjusted to an appropriate moisture content according to the particle size. [Means for solving the problem]

[0008] (1) A method for adjusting the moisture content of raw materials according to one embodiment of the present disclosure is: In a humidity control facility having a conveying line for conveying raw materials crushed by a crusher, a measuring device for measuring the particle size of the conveyed raw materials, and a humidity control device for controlling the humidity of the raw materials whose particle size has been measured, a method for adjusting the moisture content of the raw materials executed by a raw material moisture content adjustment device, To obtain the particle size measured from the measuring device, This includes changing the target value of the raw material moisture content of the humidity control unit based on the measured particle size.

[0009] (2) As one embodiment of the present disclosure, in (1), The measuring device continuously measures the particle size, Changing the target value includes calculating the measured change in particle size, predicting the time at which the particle size will fall outside a predetermined target particle size range based on the change, and outputting a signal to the humidity control device at the predicted time to change the target value of the raw material moisture content.

[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) A method for producing coke according to one embodiment of the present disclosure is: The target value of the raw material moisture content of the humidifier is changed by any of the raw material moisture content adjustment methods (1) to (3), and coke is produced by heating coal, whose raw material moisture content has been adjusted by the humidifier, in a coke oven, provided that the raw material is coal.

[0012] (5) A raw material moisture content adjustment device according to one embodiment of the present disclosure is A raw material moisture content adjustment device used in a humidity control facility that includes a conveying line for conveying raw materials crushed by a crusher, a measuring device for measuring the particle size of the conveyed raw materials, and a humidity control device for adjusting the humidity of the raw materials whose particle size has been measured, An acquisition unit that acquires the particle size measured from the aforementioned measuring device, The system includes a calculation unit that changes the target value of the raw material moisture content of the humidity control unit based on the measured particle size. [Effects of the Invention]

[0013] According to this disclosure, it is possible to provide a method for adjusting the moisture content of raw materials that can be adjusted to an appropriate moisture content according to the particle size, a method for producing coke, and an apparatus for adjusting the moisture content of raw materials. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 shows the overall configuration of the raw material moisture content adjustment equipment. [Figure 2] Figure 2 is a detailed view of a part of the humidity control equipment shown in Figure 1. [Figure 3] Figure 3 shows an example of the configuration of a raw material moisture content adjustment device according to one embodiment of the present disclosure. [Figure 4]FIG. 4 is a flowchart illustrating the processing of a method for adjusting the raw material moisture content according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram illustrating 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 of calculating the change in particle size from the time-series data of FIG. 5.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, a method for adjusting the raw material moisture content, a method for producing coke, and a raw material moisture content adjusting 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 a raw material moisture content adjusting facility (humidifying facility). FIG. 2 is a detailed view of a part 10 of the humidifying facility of FIG. 1, including a measuring device 13 and a raw material moisture content adjusting device 14. FIG. 3 is a block diagram showing a configuration example of the raw material moisture content adjusting device 14. The raw material moisture content adjusting device 14 is used in a humidifying facility having a transport line for transporting the raw material pulverized by a pulverizer 2, a measuring device 13 for measuring the particle size of the transported raw material, and a humidifying machine 4 for humidifying the raw material whose particle size has been measured. As will be described below, the raw material moisture content adjusting device 14 changes the target value of the raw material moisture content according to the particle size.

[0016] The humidity control equipment shown in Fig. 1 indicates the coal humidity control line for a coke oven. In this embodiment, the raw material is coal. Here, the raw material may be any material that is pulverized so that the variation in particle size is small, and is not limited to coal. The coal stored in Yard 1 for each brand is transported to the crusher 2 for each brand and pulverized so that the particle size is within the target particle size range. Here, the particle size refers to the ratio of the particle diameter within a predetermined range (for example, 6 mm or more) (see Fig. 5). The particle diameter is determined by the shorter side of the ellipse obtained by approximating the raw material as an ellipse. Therefore, the particle size is determined by the ratio of the shorter side of the ellipse obtained by approximating the raw material as an ellipse within a predetermined range. Also, the target particle size range is the range that the particle size of the pulverized coal 12 should 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 of Fig. 1, three crushers 2 are shown, but one or more crushers may be used, and the number of crushers 2 is not limited to a specific number.

[0017] The pulverized coal 12 is put into the humidity controller 4, and the moisture content is adjusted (humidity controlled) so as to reach the target value of the raw material moisture content. The humidity controller 4 operates according to the control signal from the raw material moisture content adjusting device 14. Here, the control signal includes an instruction to change the target value of the raw material moisture content of the humidity controller 4. A known device capable of humidifying and dehumidifying may be used for the humidity controller 4. For example, the humidity controller 4 performs humidity control so that the moisture content reaches the target value by heating the coal using steam as a heat source. Also, the humidity controller 4 may be equipped with a function to measure the raw material moisture content, or a moisture meter may be further installed before and after the humidity controller 4. For example, the raw material moisture content adjusting device 14 may acquire the measurement result of the moisture meter and change the amount of heat of the steam in the humidity controller 4 based on the deviation from the target value of the raw material moisture content.

[0018] Furthermore, 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. In other words, the measuring device 13 is provided on the belt conveyor 11 on the inlet side of the humidity control unit 4. 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. The coal, whose raw material moisture content has been adjusted by the humidity control unit 4, is transported to the coke oven 5, heated, and carbonized to produce coke. If the measuring device 13 were to be provided on the exit side of the humidity control unit 4, it would be measuring pseudo-particles, resulting in an inaccurate calculation of the particle size. Therefore, it is preferable that the measuring device 13 be provided on the belt conveyor 11 on the inlet side of the humidity control unit 4.

[0019] As shown in Figure 2, the crushed coal 12 is transported by a belt conveyor 11 to a humidity control unit 4. The measuring device 13 measures the crushed coal 12. The measuring device 13 outputs the measurement result to the raw material moisture content adjustment device 14. The measurement result is the particle size measured by the measuring device 13. In this embodiment, the measuring device 13 is an optical particle size analyzer that 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 a two-dimensional region of the crushed coal 12 from the captured two-dimensional image and calculates the particle size using a known method (image processing). For example, the particle size may be calculated from the brightness information of the captured two-dimensional image. Image processing may include, for example, binarization and contour extraction. Also, the particle size may change moment by moment, but generally it changes smoothly. Since the action of changing the target value of the raw material moisture content is performed, for example, once every few hours, it is sufficient if the particle size is calculated at shorter time intervals. For example, the particle size can be calculated at one-minute intervals.

[0020] As shown in Figure 3, the raw material moisture content adjustment device 14 comprises an acquisition unit 15, a calculation unit 16, and an output unit 17. The acquisition unit 15 acquires the particle size measured from the measuring device 13. The calculation unit 16 changes the target value of the raw material moisture content of the humidity control unit 4 based on the measured particle size. Changing the target value may include calculating the change in the measured particle size, predicting the time when the particle size will fall outside a predetermined target particle size range from the change, and outputting a signal to the humidity control unit 4 to change the target value of the raw material moisture content at the predicted time. Details of the time prediction will be described later. In this embodiment, the output of the signal (control signal) to change the target value is performed by the output unit 17. That is, the output unit 17 outputs a signal to change the target value of the raw material moisture content of the humidity control unit 4 at the time predicted by the calculation unit 16. The raw material moisture content adjustment device 14 may be 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 moisture content adjustment device 14 is a computer used in the humidity control equipment. Also, in this embodiment, the target particle size range is stored in the computer's memory.

[0021] Figure 4 is a flowchart illustrating the process of adjusting the moisture content of raw materials, which is performed by the raw material moisture content adjustment device 14 in the humidity control equipment.

[0022] The acquisition unit 15 acquires a predetermined target granularity range from, for example, a storage device (step S1).

[0023] Furthermore, the acquisition unit 15 acquires the particle size of the raw material measured from the measuring device 13 (step S2).

[0024] The calculation unit 16 predicts the time to change the target value of the raw material moisture content of the humidity control unit 4 based on the measured particle size and target particle size range 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 falls outside the target particle size range from the change.

[0025] The calculation 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 calculation unit 16 uses the newly measured particle size to predict the time to change the target value of the raw material moisture content of the humidity control unit 4 (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.

[0026] If the calculation unit 16 does not have enough time until the predicted time (No. in step S4), it proceeds to the process in step S5. Then, when the time predicted by the calculation unit 16 arrives, the output unit 17 outputs a signal to the humidity control unit 4 to change the target value of the raw material moisture content (step S5). The output signal is, for example, a control signal to the humidity control unit 4.

[0027] In step S3, the calculation unit 16 calculates the change in the measured particle size. However, if the trend is to maintain the particle size within the target range or to become coarser, there is no need to change the target value of the raw material moisture content, and the ongoing operation can be continued as is. In other words, if the trend is to maintain the particle size within the target range or to become coarser (and there is no trend towards finer particle size), the calculation unit 16 can terminate the series of processes without executing steps S4 and beyond.

[0028] The effects of this disclosure will be described in detail below based on the examples, but this disclosure is not limited to these examples.

[0029] Figure 5 illustrates the time-series data of the proportion of coarse coal particles with a particle size of 6 mm or more when particle size is measured continuously. Here, coarse coal refers to coal with a large particle size, as described above. A small proportion of coarse coal means a large proportion of fine coal. Fine coal refers to coal with a particle size of less than 2 mm, for example. If one attempts to directly measure fine coal with the measuring device 13, accurate measurement may be difficult due to limitations in the resolution of the camera of the measuring device 13. Therefore, it is preferable to measure coarse coal and indirectly measure fine coal from the relationship between the proportion of coarse and fine coal. From Figure 5, it can be seen that the particle size of coal 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 humidity control equipment after crushing.

[0030] 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. In detail, Figure 6 shows the measurement results from "15:00" to "15:22" 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, and a regression equation was calculated from the value of the average particle size. As a result, the regression equation was y = -0.1153x + 13.731, indicating that the particle size changes in a way that decreases by 0.1153% per minute. Here, y is the percentage of coarse coal particles of 6 mm or more [%]. Also, x is the time elapsed from "15:00" [minutes]. According to the regression equation, the time when the particle size falls below the lower limit of the target particle size range, which is the target particle size lower limit 101, is predicted to be 84 minutes later, or "16:24". For example, in Figure 5, data below the target particle size lower limit of 101 is shown shortly before "17:00". In this embodiment, the target particle size lower limit of 101 is 4%. Also, in this embodiment, the target particle size range for the proportion of coarse coal particles of 6 mm or larger is 4% to 12%. However, the numbers such as 4% and 12% are just examples. The target particle size lower limit of 101 and the target particle size range are not limited to specific values.

[0031] Then, the raw material moisture content adjustment device 14, at the predicted time (16:24 in this example), takes into account the yield and other operational conditions, and causes the humidity control unit 4 to change the target value of the raw material moisture content. In this example, since the raw material moisture content adjustment device 14 indicated a tendency for the amount of fine particles to increase, it changes the moisture content to a lower value than the current target value to avoid an excessive increase in moisture content. This type of control makes it possible to adjust the raw material moisture content appropriately according to the particle size based on predictions. In addition, since the formation of pseudo-particles is suppressed by adjusting the raw material moisture content, a reduction in coke strength can be avoided.

[0032] As described above, the raw material moisture content adjustment method, coke manufacturing method, and raw material moisture content adjustment device 14 according to this embodiment can adjust the raw material moisture content to an appropriate level according to the particle size. As explained in the above embodiment, a target particle size range is set in advance, the time when the particle size of the raw material after crushing will fall outside the target particle size range is predicted, and a signal is output to the humidity control device 4 to change the target value of the raw material moisture content at the predicted time. Through this control, the raw material moisture content is adjusted to an appropriate level according to the particle size, and for example, in coke production, the formation of pseudo-particles that reduce coke strength can be suppressed. Furthermore, since the time to change the target value of the raw material moisture content is determined in advance, the workload on the operator does not become excessive. In addition, since the target value only needs to be changed when it is predicted that the particle size of the raw material after crushing will fall outside the particle size range, the humidity control equipment does not bear a heavy load.

[0033] 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.

[0034] For example, in the above embodiment, the coal is crushed according to its brand, but the humidity control equipment is not limited to such equipment. For example, the contents of this disclosure can also be applied to coke production methods that do not include a crushing process. Coal has different particle sizes depending on its brand. Also, in yard 1, the particle size tends to be larger at the base of the pile and smaller at the top. Therefore, as the cutting position of the pile changes in yard 1, the particle size of the coal charged into the humidity control unit 4 may change from moment to moment.

[0035] For example, in the above embodiment, the crushed coal 12 was identified from a two-dimensional image captured by a camera. In another example, the measuring device 13 may be a laser rangefinder or the like, which performs three-dimensional measurement, uses the obtained three-dimensional data to identify the crushed coal 12, and calculates the particle size of the crushed coal 12.

[0036] Furthermore, the raw material moisture content adjustment 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 moisture content adjustment device 14 as a whole. Therefore, for example, the raw material moisture content adjustment 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, in the calculation unit 16 of the raw material moisture content adjustment device 14, the part that calculates the change in measured particle size and the part that changes the target value of the raw material moisture content (the part that calculates the new target value of the raw material moisture content) may be implemented by different devices.

[0037] Furthermore, if the raw material moisture content adjustment device 14 is configured as a computer, one or more programs used to control the operation of the raw material moisture content adjustment 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, an arithmetic unit 16, and an output unit 17. The computer may then execute the process for adjusting the raw material moisture content. [Explanation of Symbols]

[0038] 1 yard 2. Crusher 3 Specific position 4. Humidifier 5. Coke oven 10. Part of the humidity control equipment 11 Belt conveyor 12. Crushed coal 13 Measuring devices 14. Device for adjusting the moisture content of raw materials 15 Acquisition Department 16 Arithmetic section 17 Output section 101 Target particle size lower limit

Claims

1. In a humidity control facility having a conveying line for conveying raw materials crushed by a crusher, a measuring device for measuring the particle size of the conveyed raw materials, and a humidity control device for controlling the humidity of the raw materials whose particle size has been measured, a method for adjusting the moisture content of the raw materials executed by a raw material moisture content adjustment device, To obtain the particle size measured from the measuring device, A method for adjusting the moisture content of raw materials, comprising changing the target value of the moisture content of raw materials in the humidity control unit based on the measured particle size.

2. The measuring device continuously measures the particle size, The method for adjusting the moisture content of raw materials according to claim 1, wherein changing the target value includes calculating the change in the measured particle size, predicting the time at which the particle size will fall outside a predetermined target particle size range from the change in the change, and outputting a signal to the humidity control device at the predicted time to change the target value of the moisture content of the raw materials.

3. The method for adjusting the moisture content of raw materials according to claim 2, wherein the predicted time is corrected based on the particle size measured after the predicted time.

4. A method for producing coke, comprising changing the target value of the raw material moisture content of the humidifier by the method for adjusting the raw material moisture content described in any one of claims 1 to 3, and producing coke by heating coal, whose raw material moisture content has been adjusted by the humidifier, in a coke oven, wherein the raw material is coal.

5. A raw material moisture content adjustment device used in a humidity control facility that includes a conveying line for conveying raw materials crushed by a crusher, a measuring device for measuring the particle size of the conveyed raw materials, and a humidity control device for adjusting the humidity of the raw materials whose particle size has been measured, An acquisition unit that acquires the particle size measured from the aforementioned measuring device, A raw material moisture content adjustment device comprising: a calculation unit that changes the target value of the raw material moisture content of the humidity control device based on the measured particle size.

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