Moisture measuring method, moisture measuring device, coal moisture conditioning method, and coke production method

Abstract

To provide a technique of precisely and stably measuring moisture when measuring moisture in a coal carried on a conveyor by using a microwave.SOLUTION: A moisture measuring method for measuring moisture in coal carried on a conveyor includes: a coal pressure reduction step of reducing the pressure of a coal carried on a conveyor and levelling out a surface of the coal and compressing the coal; a layer thickness measuring step of measuring a layer thickness of the coal after the pressure of the coal is reduced in the coal pressure reduction step; a microwave sending step for sending a microwave as a transmission wave to the coal after the pressure of the coal is reduced in the coal pressure reduction step; a microwave receiving step of receiving the microwave which was sent in the microwave sending step and passed through the coal as a reception wave; a microwave change amount calculation step of comparing the transmission wave and the reception wave and calculating a change amount; and a water content calculation step of calculating a water content of the coal on the basis of the change amount calculated by the microwave change amount calculation step and the layer thickness of the coal measured in the layer thickness measuring step.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a moisture measuring method and moisture measuring device, a moisture control method for coal, and a method for producing coke. [Background technology]

[0002] In steel plants, coal, which is the raw material for coke, is transported on a conveyor belt, dried by a moisture control machine, and then loaded into the coke oven. Generally, the lower the moisture content of the raw coal, the higher the quality of the coke. However, if the moisture content is too low, problems such as increased coal dust generation during transportation, risk of fire, and clogging of the coke oven occur. For this reason, it is necessary to control the moisture content within a specified range.

[0003] Therefore, there are techniques that use microwaves to measure the moisture content of coal. For example, Patent Documents 1 to 3 propose techniques in which microwaves are irradiated onto coal on a belt conveyor and the moisture content of the coal is measured from changes in the propagation characteristics of the microwaves in the coal.

[0004] Specifically, Patent Document 1 proposes a technique for leveling the surface of coal on a belt conveyor using a scraper to physically make the bulk density uniform, and then measuring the moisture content using microwaves. Patent Document 2 proposes a moisture measuring device that includes a distance meter for measuring layer thickness and a weighing machine for measuring weight, and corrects data measured by the microwave moisture meter based on layer thickness and on bulk density calculated from the layer thickness and weight. Patent Document 3 proposes a method for measuring moisture content without being affected by bulk density fluctuations by embedding a microwave moisture meter in the coal layer.

[0005] Furthermore, Patent Document 4 proposes a technology for measuring both the density and moisture content of an object to be measured from the amount of attenuation and phase between microwaves that have not passed through the object and microwaves that have passed through the object. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-55726 [Patent Document 2] Japanese Patent Application Publication No. 6-129980 [Patent Document 3] JP 2014-112053 A [Patent Document 4] JP 2019-70535 A Summary of the Invention [Problem to be solved by the invention]

[0007] Microwave moisture measurement technology requires bulk density information. Usually, bulk density is measured by utilizing the property that gamma rays, a type of radiation, are weakened when they pass through a material. However, the handling of gamma rays is strictly regulated, and the method of measuring bulk density using gamma rays requires management costs.

[0008] On the other hand, the techniques described in Patent Documents 1 to 4 do not use gamma ray bulk density measurement, so they do not have the above-mentioned inconveniences, but they have the following problems. That is, in the technique of Patent Document 1, the surface of the coal on the belt conveyor is leveled with a leveling plate (scraper) without measuring the bulk density, and the bulk density is physically uniformed. In that case, the layer thickness varies greatly due to the fluctuation in the transport amount of the measured object, and if the surface of the measured object is below the movable range of the leveling plate (scraper), correction becomes impossible. In addition, there is a problem that the measured object falls from the belt conveyor because the leveling plate (scraper) bounces the measured object. The technique disclosed in Patent Document 3 also has a similar problem that the measured object is bounced by a box with a microwave moisture meter installed inside and falls from the belt conveyor. In the technique described in Patent Document 2, the layer thickness and bulk density are measured and used to correct the moisture meter, but if the shape of the coal layer surface in the range irradiated with microwaves is not flat, an error will occur in the measured layer thickness and bulk density itself. Furthermore, with the technique of measuring the density of an object from the amount of attenuation and the amount of phase as in Patent Document 4, it is difficult to measure the bulk density with high accuracy.

[0009] The present invention provides a technique that enables highly accurate and stable moisture measurement when measuring the moisture content of coal transported on a conveyor using microwaves. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides the following means [1] to

[13] .

[0011] [1] A moisture measurement method for measuring the moisture content of coal transported on a conveyor, comprising the steps of: a coal crushing step of crushing the coal on the conveyor to level the surface of the coal and compress the coal; a layer thickness measuring step of measuring a layer thickness of the coal after the coal is crushed by the coal crushing step; a microwave transmitting step of transmitting microwaves as transmission waves toward the coal after it has been suppressed by the coal suppression step; A microwave receiving step of receiving the microwaves transmitted in the microwave transmitting step and transmitted through the coal as received waves; a microwave change amount calculation step of calculating a change amount by comparing the transmitted wave with the received wave; a moisture content calculation step of calculating a moisture content of the coal based on the change amount calculated in the microwave change amount calculation step and the layer thickness of the coal measured in the layer thickness measurement step; A moisture measurement method comprising:

[0012] [2] The moisture measurement method described in [1], wherein the coal crushing step crushes the coal using a roller whose rotating shaft is installed parallel to the width direction of the conveyor and movable in the height direction of the conveyor.

[0013] [3] The moisture measurement method described in [1], wherein the coal-settling process includes a bottom surface of the conveyor that is a flat surface that contacts the coal on the conveyor and is kept parallel to the conveyor, and an inclined surface that curves upward from the bottom surface on the upstream side of the conveyor's traveling direction, and the coal is suppressed by a weight that is movable in the height direction of the conveyor.

[0014] [4] The moisture measurement method according to [1], wherein the change calculated in the microwave change calculation step includes one or both of a phase difference and an attenuation rate.

[0015] [5] A moisture measurement method described in any one of [1] to [4], wherein the microwaves used are of multiple frequencies.

[0016] [6] The moisture measurement method according to any one of [1] to [4], wherein the coal crushing step is carried out in an upward gradient portion of the conveyor.

[0017] [7] A moisture measuring device for measuring the moisture content of coal transported on a conveyor, comprising: a coal crushing mechanism that crushes the coal on the conveyor to level the surface of the coal and compress the coal; A layer thickness measuring unit that measures the layer thickness of the coal after it has been crushed by the coal crushing mechanism; A microwave transmitting unit that transmits microwaves as transmission waves toward the coals suppressed by the coal suppression mechanism; A microwave receiving unit that receives the microwave transmitted from the microwave transmitting unit and transmitted through the coal as a received wave; a microwave change amount calculation unit that compares the transmitted wave with the received wave to calculate an amount of change; a moisture content calculation unit that calculates a moisture content of the coal based on the change amount calculated by the microwave change amount calculation unit and the layer thickness of the coal measured by the layer thickness measurement unit; A moisture measuring device comprising:

[0018] [8] The layer thickness measuring unit is a distance meter for measuring a distance to a surface of the coal after it has been crushed by the coal crushing mechanism; a layer thickness calculation unit that calculates a layer thickness of the coal after the suppression based on the distance value measured by the distance meter; The moisture measuring device according to [7],

[0019] [9] The moisture measuring device described in [7], wherein the coal crushing mechanism is a roller whose rotation axis is installed parallel to the width direction of the conveyor and movable in the height direction of the conveyor.

[0020]

[10] The moisture measuring device described in [7], wherein the coal-pressing mechanism is a weight that has a bottom surface that is a flat surface that contacts the coal on the conveyor and is kept parallel to the conveyor, and an inclined surface that curves upward from the bottom surface upstream in the direction of travel of the conveyor, and is movable in the height direction of the conveyor.

[0021]

[11] The moisture measuring device described in any one of [7] to

[10] , wherein the coal crushing mechanism is installed on an upward gradient portion of the conveyor.

[0022]

[12] A method for adjusting the moisture content of coal, comprising measuring the moisture content of coal by the moisture measurement method described in [1] above, and adjusting the moisture content of the coal by drying or adding water based on the measured moisture content so that the moisture content of the coal falls within a set range.

[0023]

[13] A method for producing coke, comprising charging coal whose moisture has been adjusted by the coal moisture adjustment method described in

[12] above into a coke oven to produce coke. Effect of the Invention

[0024] According to the present invention, the coal on the conveyor is pressed down to level the coal surface and compress the coal, thereby reducing the variation in the coal bulk density and simultaneously reducing the variation in the coal layer thickness in the range through which the microwaves penetrate, and the layer thickness is measured and the amount of change in the microwave transmission and reception waves is calculated, and the moisture content of the coal is calculated based on these, making it possible to perform highly accurate and stable moisture measurement. Also, because the coal is pressed down from above and pressed down, the coal on the conveyor is not thrown off the conveyor. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a side view that illustrates a schematic view of a moisture measuring device according to a first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of a coal crushing mechanism included in the moisture measuring device of FIG. 1, viewed from the downstream side in the conveying direction of a belt conveyor. [Diagram 3] 2 is a flowchart showing a moisture measuring method using the moisture measuring device of FIG. [Figure 4] FIG. 4 is a side view that illustrates a schematic view of a moisture measuring device according to a second embodiment of the present invention. [Diagram 5] 5 is a cross-sectional view of a coal crushing mechanism included in the moisture measuring device of FIG. 4, viewed from the downstream side in the conveying direction of the belt conveyor. [Figure 6] FIG. 11 is a side view showing a schematic diagram of a coal crushing mechanism included in a moisture measuring device according to a third embodiment of the present invention. [Figure 7] 7 is a cross-sectional view of the coal crushing mechanism of FIG. 6 as viewed from the downstream side in the conveying direction of the belt conveyor. [Figure 8]FIG. 11 is a side view showing a schematic view of a coal crushing mechanism included in a moisture measuring device according to a third embodiment, installed on a belt conveyor with an upward gradient at an angle θ from the horizontal direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0027] <First embodiment> FIG. 1 is a side view showing a schematic diagram of a moisture measuring device according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a coal crushing mechanism included in the moisture measuring device of FIG. 1, as viewed from the downstream side in the conveying direction of a belt conveyor.

[0028] The moisture measuring device 1 measures the moisture content of coal C transported on a belt conveyor B shown in FIG. 1 in the direction of the arrow V in the figure. The coal C is transported to a moisture control facility by the belt conveyor B, where it is dried (or hydrated) so that the moisture content falls within a set range based on the moisture content measured by the moisture measuring device 1. The coal with the adjusted moisture content is then charged into a coke oven to produce coke. Note that FIG. 1 shows an example in which the moisture measuring device 1 is provided in the upstream stage of the moisture control facility, but the moisture measuring device 1 may be provided in the downstream stage of the moisture control facility, or may be provided in both the upstream and downstream stages of the moisture control facility. Even if the moisture measuring device 1 is provided only in the downstream stage of the moisture control facility, if the moisture content measured by the moisture measuring device 1 deviates from the set range, the intensity of drying (or hydration) is adjusted so that the moisture content falls within the set range.

[0029] The moisture measuring device 1 includes a coal crushing mechanism 2, a layer thickness measuring unit 3, a microwave transmitting unit 41, a microwave receiving unit 42, a microwave change amount calculating unit 43, and a moisture content calculating unit 5.

[0030] The coal crushing mechanism 2 is composed of a roller 21 for crushing the coal C on the belt conveyor B in advance and an arm 22 for holding the roller 21. As shown in FIG. 2, the roller 21 has its rotation shaft 21a arranged parallel to the width direction of the belt conveyor B. The rotation shaft 21a of the roller 21 is held by the arm 22. The arm 22 extends obliquely upward from the rotation shaft 21a, and its upper end is rotatably held by the shaft S, and is configured to be swingable with respect to the shaft S as shown in FIG. 1. The arm 22 is swung, so that the roller 21 can move up and down. The roller 21 crushes the coal C transported on the belt conveyor B from above, leveling the surface of the coal C and compressing the coal C. The roller 21 also moves up and down following the fluctuation of the surface height of the coal C. The crushing by the roller 21 is performed by the weight of the roller 21, so that the roller 21 has a weight sufficient to compress the coal C. Furthermore, in order to suppress the roller 21 from bouncing up and improve the ability to follow fluctuations in the surface height of the coal C, an additional load may be applied in the downward direction of the arm 22 using a spring or the like.

[0031] The layer thickness measurement unit 3 has a distance meter 31 and a layer thickness calculation unit 32. The distance meter 31 is installed on the belt conveyor B downstream of the coal crushing mechanism 2 and measures the height of the surface of the crushed coal C, i.e., the layer thickness of the coal C. The distance meter 31 is, for example, an ultrasonic distance meter, which transmits ultrasonic waves U toward the surface of the coal C, receives the reflected waves, measures the time from transmitting the ultrasonic waves U to receiving them, and converts it into the distance between the distance meter 31 and the surface of the coal C based on the speed of sound. The layer thickness calculation unit 32 is a calculation device that calculates the layer thickness of the coal C on the belt conveyor B based on the measurement value of the distance meter 31. The layer thickness calculation unit 32 previously holds the value of the distance meter 31 when there is no coal C on the belt conveyor B, i.e., the distance to the surface of the belt conveyor B, and calculates the layer thickness of the coal C by taking the difference from the measurement value of the distance meter 31.

[0032] The advantage of using an ultrasonic type as the range finder 31 is that it is possible to perform measurements without being affected even when dust is generated. Note that the range finder 31 is not limited to an ultrasonic type, and may be a laser type, a TOF (Time of Flight) type, a stereo camera, or the like, depending on the measurement environment.

[0033] The layer thickness measuring unit 3 may measure the layer thickness of the coal C by measuring the height of the roll 21 of the coal crushing mechanism 2. For example, a method of measuring the height of the roll 21 with a contact or non-contact sensor, or a method of measuring the rotation angle of the arm 22 with a potentiometer attached to the shaft S and converting it into a layer thickness in a layer thickness calculating unit may be adopted.

[0034] The microwave transmitter 41 transmits microwaves as transmission waves toward the coal bed after it has been suppressed. Specifically, it transmits microwaves of a predetermined energy and phase. The microwave receiver 42 receives the microwaves transmitted from the microwave transmitter 41 and transmitted through the coal C as received waves. The microwave transmitter 41 and the microwave receiver 42 are each formed of, for example, a horn antenna, and are positioned in positions facing each other with the coal C in between, after the coal C on the belt conveyor B has been suppressed.

[0035] The microwave change amount calculation unit 43 is connected to the microwave transmission unit 41 and the microwave reception unit 42 via cables, and calculates the amount of change by comparing the transmission wave transmitted from the microwave transmission unit 41 with the reception wave received by the microwave reception unit 42. The amount of change may include one or both of a phase difference and an attenuation rate (energy ratio). The microwave change amount calculation unit 43 not only calculates the amount of change in the microwave, but also controls the operation of the microwave transmission unit 41 and the microwave reception unit 42.

[0036] Conditions such as the wavelength of the microwaves used and the distance between the microwave transmitting unit 41 and the microwave receiving unit 42 can be set appropriately depending on the brand and type of coal C. Furthermore, a comparison of transmitted and received microwaves of a plurality of frequencies (wavelengths) may be performed to determine the amount of change for each frequency (i.e., frequency characteristics).

[0037] The moisture content calculation unit 5 calculates the moisture content of the coal C by using the amount of change between the transmitted wave and the received wave of the microwave W calculated by the microwave change amount calculation unit 43 and the layer thickness of the coal C calculated by the layer thickness calculation unit. Specifically, the moisture content calculation unit 5 calculates the moisture content M (%) of the coal C by the following formula (1), where the phase difference is Φ (deg), the attenuation rate is A (dB), and the layer thickness is D (mm). M = (K Φ ×Φ / D)+(K A ×A / D) + K C (1) Here, K Φ , K A , K C is a coefficient that is preset according to the brand and type of coal C, the distance between the microwave transmitting unit 41 and the microwave receiving unit 42, the material and thickness of the belt conveyor B, etc.

[0038] In addition, the coefficient K Φ , K A , K C may be a coefficient that is determined in advance using many samples of coal C prepared in advance. Specifically, the coefficient K is determined by the following procedure. Φ , K A , K C can be determined in advance. That is, for a plurality of samples (at least three or more samples of coal C) prepared in advance, the moisture content M is calculated based on the JIS standard (analytical moisture content) JIS M 8811: 2000 Coals and cokes - Method for determining total moisture content of a lot. In addition, the phase difference Φ, attenuation factor A, and layer thickness D of these samples are also measured. Then, the coefficient K in the above formula (1) is calculated based on the moisture content M, phase difference Φ, attenuation factor A, and layer thickness D of these samples. Φ , K A , KC Determine.

[0039] Next, a moisture measuring method using the moisture measuring device 1 configured as above will be described. FIG. 3 is a flowchart showing a moisture measuring method using the moisture measuring device of FIG. First, the coal C on the conveyor B is pressed down from above to level the surface of the coal C and compress the coal C (coal pressing step; step ST1). In this embodiment, this coal pressing step is performed by the rollers 21 of the coal pressing mechanism 2.

[0040] Next, the layer thickness of the coal C after being pressed on the conveyor B is measured (layer thickness measurement step; step ST2). The layer thickness of the coal C can be measured, for example, by measuring the height of the surface of the coal C with a range finder 31 and performing calculations with a layer thickness calculation unit 32. As described above, an ultrasonic range finder can be suitably used as the range finder 31.

[0041] Next, microwaves are transmitted as transmission waves toward the compacted coal C in step ST1 on the conveyor B (microwave transmission step; step ST3). The microwaves are transmitted by a microwave transmitter 41 made of, for example, a horn antenna. The microwave transmitter 41 transmits microwaves W of a predetermined energy and phase.

[0042] Then, the microwaves that have been transmitted and passed through the coal seam are received as received waves (microwave receiving step; step ST4). The microwaves are received by a microwave receiving unit 42 that is made up of, for example, a horn antenna.

[0043] Next, the transmitted wave and the received wave are compared to calculate the amount of change (microwave change amount calculation step; step ST5). This step is performed by the microwave change amount calculation unit 43. The amount of change may include one or both of a phase difference and an attenuation rate (energy ratio).

[0044] Next, the moisture content of the coal C is calculated based on the amount of change in the microwave calculated in step ST5 and the layer thickness of the coal C measured in step ST2 (moisture content calculation step; step ST6). This step is performed by the moisture content calculation unit 5. The moisture content is calculated based on the above-mentioned formula (1).

[0045] In this manner, in this embodiment, when measuring the moisture content of the coal C on the conveyor B, the above steps ST1 to ST6 are carried out, whereby the following effects can be obtained.

[0046] Coal C is usually transported on the belt conveyor B after being cut from a hopper or transferred from another belt conveyor. In other words, since coal C is simply dropped onto the belt conveyor, there are many voids between the coal particles, and the bulk density is low and varies widely.

[0047] In contrast, in this embodiment, the coal C on the conveyor B is crushed by the coal crushing mechanism 2, so that the coal C is compressed, the gaps between the coal C particles are reduced, and the bulk density is increased. If the particle size distribution is constant, the fluctuation in the bulk density after crushing is small, and the bulk density is almost constant. The phase difference and attenuation rate calculated by the microwave change amount calculation unit 43 and included in the formula (1) are amounts that depend on the bulk density of the coal C and the layer thickness of the coal C. Therefore, the bulk density becomes almost constant by crushing, and the layer thickness in the range through which the microwaves pass becomes known, so that the measurement accuracy of the moisture content calculated by the formula (1) is improved. In addition, the coal C is crushed and the surface of the coal C is made flat and uniform, so that the variation in the layer thickness in the range through which the microwaves W pass (the range between the microwave transmitting unit 41 and the microwave receiving unit 42) is reduced, and the measurement accuracy of the moisture content can be further improved.

[0048] Furthermore, since the coal C on the conveyor B is compressed, the coal C can be prevented from being thrown out of the conveyor B.

[0049] Furthermore, since the bulk density of coal C can be made almost constant by pressing the coal C, there is no need to include the bulk density as a variable in the formula for calculating the moisture content of coal C, as described in Patent Document 1, and there is no need to measure the bulk density by gamma rays.

[0050] <Second embodiment> Fig. 4 is a side view showing a schematic diagram of a moisture measuring device according to a second embodiment of the present invention, and Fig. 5 is a cross-sectional view of a coal crushing mechanism included in the moisture measuring device of Fig. 4, seen from the downstream side in the conveying direction of the belt conveyor. The second embodiment is the same as the first embodiment, except that a coal crushing mechanism 2' is provided instead of the coal crushing mechanism 2 of the first embodiment, so the other components are denoted by the same reference numerals as in the first embodiment, and description thereof will be omitted.

[0051] In the second embodiment, the coal crushing mechanism 2' comprises a weight 23 for pre-crushing the coal C on the belt conveyor B, and a pair of first arms 24a (only one of which is shown) and a pair of second arms 24b (only one of which is shown) that hold it.

[0052] Weight 23 has a bottom surface which is a flat surface kept parallel to belt conveyor B, and a chamfered portion 23a which is an inclined surface that curves upward from the bottom surface on the upstream side of the direction of travel of belt conveyor B (the direction of arrow V in the figure), and chamfered portion 23a is designed to guide the transported coal C to the bottom of weight 23.

[0053] The pair of first arms 24a have their lower ends rotatably connected to the weight 23 via shaft 25a, and the pair of second arms 24b have their lower ends rotatably connected to the weight 23 via shaft 25b. The first arm 24a and the second arm 24b extend parallel to each other diagonally upward from their lower ends connected by shaft 25a and shaft 25b. The upper ends of the pair of first arms 24a are held by shaft S1, and the upper ends of the pair of second arms 24b are held by shaft S2. The first arm 24a and the second arm 24b are configured to be swingable relative to shaft S1 and shaft S2, and by swinging the first arm 24a and the second arm 24b, the weight 23 can be moved up and down while keeping the bottom surface of the weight 23 parallel to the belt conveyor B. The weight 23 presses down on the coal C transported on the belt conveyor B from above to compress it and level the surface of the coal C, while moving up and down in response to fluctuations in the surface height of the coal C. Since the compression by the weight 23 is performed by the weight of the weight 23 itself, a weight that is heavy enough to compress the coal C is used as the weight 23. Furthermore, in order to suppress the weight 23 from bouncing up and to improve the ability to follow fluctuations in the surface height of the coal C, an additional load may be applied by a spring or the like in the direction of lowering the first arm 24a and the second arm 24b.

[0054] In this embodiment, the coal C is crushed by the weight 23 of the coal crushing mechanism 2′, and the same effects as those of the first embodiment can be obtained by steps ST1 to ST6 of the first embodiment.

[0055] <Third embodiment> Fig. 6 is a side view showing a schematic diagram of a coal crushing mechanism included in a moisture measuring device according to a third embodiment of the present invention, and Fig. 7 is a cross-sectional view of the coal crushing mechanism shown in Fig. 6, seen from the downstream side in the conveying direction of the belt conveyor. The third embodiment is the same as the second embodiment, except that, instead of the coal crushing mechanism 2' of the second embodiment, a coal crushing mechanism 2" is provided in which the weight 23 is changed to a sled-shaped plate 23'. Therefore, the other components are given the same reference numerals as in the second embodiment, and description thereof will be omitted.

[0056] The sled-shaped plate 23' has a weight necessary for crushing the coal C on the belt conveyor B, similar to the weight 23 of the second embodiment, and has a bottom surface that is a plane that is kept parallel to the belt conveyor B and an inclined surface 23'a that is warped upward from the bottom surface on the upstream side of the traveling direction of the belt conveyor B (the direction of the arrow V in the figure). In this way, the sled-shaped plate 23' functions as a weight for crushing the coal, and has a shape in which the surface that contacts the coal C on the belt conveyor B has a bottom surface that is kept parallel to the belt conveyor B and an inclined surface 23'a that is warped upward from the bottom surface on the upstream side of the traveling direction of the belt conveyor B, and therefore has the same function as the weight 23 of the second embodiment. Therefore, the same effect as the second embodiment can be obtained.

[0057] In this embodiment, the coal crushing mechanism 2" may be installed on the upward gradient portion of the belt conveyor B. FIG. 8 is a side view showing a schematic view of the coal crushing mechanism 2" included in the moisture measuring device according to the third embodiment installed on the belt conveyor B with an upward gradient at an angle θ from the horizontal direction. When the coal crushing mechanism 2" is installed on the belt conveyor B with an upward gradient, a force F acts in the opposite direction to the traveling direction V of the belt conveyor B as a component force of gravity acting on the sled-shaped plate 23'. As a result, a force is generated that pushes back the coal C that hits the inclined surface 23'a in the upstream direction (opposite direction to V), which increases the effect of leveling out the surface unevenness of the coal C. That is, in addition to the effect that the coal C is crushed by the sled-shaped plate 23' and the bulk density is stabilized to a substantially constant value, the short-term fluctuation in the layer thickness of the coal C is reduced. Also, the effect of suppressing the layer thickness fluctuation is obtained. By suppressing the short-term fluctuation in layer thickness, the variability in the measurement of the amount of change (phase difference, attenuation) during microwave transmission is also suppressed, resulting in improved measurement accuracy of the moisture content of coal C. The angle θ of the upward gradient of belt conveyor B is preferably 10 to 15°. If θ is less than 10°, the effect of suppressing layer thickness fluctuation is reduced. A gradient of more than 15° is generally difficult to apply because it exceeds the limit gradient when transporting coal with a flat belt conveyor.

[0058] The coal crushing mechanism 2 of the first embodiment and the coal crushing mechanism 2' of the second embodiment may also be installed on the upward gradient portion of the belt conveyor B, and the same effects as those of this embodiment can be obtained. In the first and second embodiments, as in this embodiment, the angle θ of the upward gradient of the belt conveyor B is preferably 10 to 15°.

[0059] Although the embodiments of the present invention have been described above, these are merely examples and should not be considered as limiting. The above embodiments may be omitted, substituted, or modified in various ways without departing from the spirit of the present invention.

[0060] For example, in the above embodiments, the process of compacting the coal is shown to be performed using rollers 21 (first embodiment), weights 23 (second embodiment), and sled-shaped plates 23' (third embodiment), but the present invention is not limited to these as long as the coal surface can be smoothed while being pressed down and compressed from above. [Explanation of symbols]

[0061] 1. Moisture measuring device 2, 2', 2" Coal Suppression Mechanism 3 Layer thickness measurement section 5 Moisture content calculation section 21 Roller 21a Rotation axis 22, 24a, 24b Arms 23 Weight 23′ Sled 25a, 25b axis 31 Distance meter 32 Layer thickness calculation section 41 Microwave transmitter 42 Microwave receiving section 43 Microwave change amount calculation section B Belt conveyor C Coal S, S1, S2 shafts

Claims

1. A moisture measurement method for measuring the moisture content of coal transported on a conveyor, comprising the steps of: a coal crushing step of crushing the coal on the conveyor to level the surface of the coal and compress the coal; a layer thickness measuring step of measuring a layer thickness of the coal after the coal is crushed by the coal crushing step; a microwave transmitting step of transmitting microwaves as transmission waves toward the coal after it has been suppressed by the coal suppression step; A microwave receiving step of receiving the microwaves transmitted in the microwave transmitting step and transmitted through the coal as received waves; a microwave change amount calculation step of calculating a change amount by comparing the transmitted wave with the received wave; a moisture content calculation step of calculating a moisture content of the coal based on the change amount calculated in the microwave change amount calculation step and the layer thickness of the coal measured in the layer thickness measurement step; A moisture measurement method comprising:

2. 2. The moisture measuring method according to claim 1, wherein the coal crushing step crushes the coal by a roller whose rotation axis is arranged parallel to the width direction of the conveyor and movable in the height direction of the conveyor.

3. 2. The moisture measurement method according to claim 1, wherein the coal-settling step comprises a bottom surface of the conveyor that is a plane that contacts the coal on the conveyor and is kept parallel to the conveyor, and an inclined surface that curves upward from the bottom surface on the upstream side of the conveyor's traveling direction, and the coal is suppressed by a weight that is movable in the height direction of the conveyor.

4. The moisture measurement method according to claim 1 , wherein the change amount calculated in the microwave change amount calculation step includes one or both of a phase difference and an attenuation rate.

5. The moisture measurement method according to claim 1 , wherein a plurality of frequencies are used as the microwave.

6. The moisture content measuring method according to claim 1 , wherein the coal crushing step is performed on an upward gradient portion of the conveyor.

7. A moisture measuring device for measuring the moisture content of coal transported on a conveyor, comprising: a coal crushing mechanism that crushes the coal on the conveyor to level the surface of the coal and compress the coal; A layer thickness measuring unit that measures the layer thickness of the coal after it has been crushed by the coal crushing mechanism; A microwave transmitting unit that transmits microwaves as transmission waves toward the coals suppressed by the coal suppression mechanism; A microwave receiving unit that receives the microwave transmitted from the microwave transmitting unit and transmitted through the coal as a received wave; a microwave change amount calculation unit that compares the transmitted wave with the received wave to calculate an amount of change; a moisture content calculation unit that calculates a moisture content of the coal based on the change amount calculated by the microwave change amount calculation unit and the layer thickness of the coal measured by the layer thickness measurement unit; A moisture measuring device comprising:

8. The layer thickness measuring unit is a distance meter for measuring a distance to a surface of the coal after it has been crushed by the coal crushing mechanism; a layer thickness calculation unit that calculates a layer thickness of the coal after compaction based on the distance value measured by the distance meter; The moisture measuring device according to claim 7 .

9. 8. The moisture measuring device according to claim 7, wherein the coal crushing mechanism is a roller whose rotation axis is arranged parallel to the width direction of the conveyor and movable in the height direction of the conveyor.

10. The moisture measuring device according to claim 7, wherein the coal-squeezing mechanism is a weight that is movable in the height direction of the conveyor and has a bottom surface that is a plane that contacts the coal on the conveyor and is kept parallel to the conveyor, and an inclined surface that curves upward from the bottom surface on the upstream side of the conveyor's traveling direction.

11. The moisture measuring device according to any one of claims 7 to 10, wherein the coal crushing mechanism is installed on an upward gradient portion of the conveyor.

12. 2. A method for adjusting moisture content of coal, comprising: measuring a moisture content of coal by the moisture measuring method according to claim 1; and adjusting the moisture content of the coal by drying or adding water based on the measured moisture content so that the moisture content of the coal falls within a set range.

13. A method for producing coke, comprising charging coal whose moisture has been adjusted by the method for adjusting the moisture content of coal according to claim 12 into a coke oven to produce coke.

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