Testing apparatus and testing method for evaluating attachment properties of granular material

Abstract

To provide a testing apparatus and a testing method with which attachment properties of granular material can be evaluated at low cost and with simple procedures.SOLUTION: A testing apparatus 1 comprises: a vibration table 2 that generates vibration in a horizontal direction; a conical hopper 4 that is attached to the vibration table 2 so as to transmit vibration from the vibration table 2, receive a sample of coal from above, and drops the sample from a lower-side discharge port; a shutter 5 that opens and closes the discharge port of the hopper 4; and a container 6 that is mounted on the vibration table 2 to be arranged below the hopper 4, and receives the sample dropped from the hopper 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a test apparatus and a test method for evaluating the adhesion of granular materials.

Background Art

[0002] In thermal power generation, low-grade coal that can be stably procured may be used. Low-grade coal contains a large amount of impurities and is likely to have high adhesiveness. Therefore, if it is used directly in thermal power generation, there is a risk of adhering to the hopper. For this reason, before the obtained coal is put into the hopper, it is necessary to grasp its adhesiveness and take countermeasures in advance. Patent Document 1 discloses a drum test, which is one of the adhesion evaluation tests for coal. In the drum test, a sample with a known moisture content is put into a hopper and preliminary vibration is applied. Then, the discharge port of the hopper is opened and the discharge time until all of the sample is discharged is measured. Based on the relationship between the moisture content of the sample and the discharge time, the adhesiveness is evaluated for each coal type.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the drum test of Patent Document 1, it is necessary to use a large amount of 12 kg of sample. Inevitably, the test apparatus becomes large and expensive to accommodate this sample. Also, it is necessary to prepare a 12 kg sample in advance by reducing and drying the coal to be tested, which also requires a lot of labor and effort in the preparation process. Such problems exist not only when evaluating the adhesiveness of coal but also when evaluating the adhesiveness of other granular materials.

[0005] The present invention has been made based on such a background, and an object thereof is to provide a test apparatus and a test method capable of evaluating the adhesiveness of granular materials at low cost and by a simple procedure.

Means for Solving the Problems

[0006] In order to achieve the above object, a test apparatus according to the present invention is a test apparatus for evaluating the adhesiveness of granular materials, comprising a vibration table that generates horizontal vibration, a conical hopper that is attached to the vibration table so that the vibration from the vibration table is transmitted, receives a sample of the granular material from above, and drops it from a lower discharge port, opening and closing means for opening and closing the discharge port of the hopper, a container that is placed on the vibration table so as to be disposed below the hopper and receives the sample dropped from the hopper, and is provided with.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a test apparatus and a test method capable of evaluating the adhesiveness of granular materials at low cost and by a simple procedure.

Brief Description of the Drawings

[0008]

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Modes for Carrying Out the Invention

[0009] Hereinafter, the test apparatus and test method according to the embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or equivalent parts are denoted by the same reference numerals. In the embodiments, the case where a granular material obtained by pulverizing coal is used as the granular material to be tested will be described as an example. Note that in the embodiments, the term "granular material" does not limit the particle size of the particles constituting the granular material, and it may be either a powder or a granule.

[0010] The method for evaluating the adhesiveness of coal according to the embodiment is a method of evaluating the adhesiveness of coal based on the discharge time of a coal sample measured when the sample is dropped from the discharge port of a hopper while vibrating the hopper of the test apparatus in the horizontal direction. The discharge time is the time from when the discharge port of the hopper is opened until all of the sample has fallen. By repeating the step of measuring the discharge time of the sample while changing the moisture content of the sample for each coal type, the relationship between the moisture content of the sample and the discharge time can be obtained for each coal type. In the adhesiveness evaluation method according to the embodiment, the discharge time is measured using a smaller amount of sample than in the durum test, and the adhesiveness of the coal is evaluated for each coal type by comparing the relationship between the moisture content of the sample and the discharge time with a preset evaluation criterion.

[0011] Hereinafter, with reference to FIG. 1, the configuration of the test apparatus 1 according to the embodiment will be described. The test apparatus 1 includes a vibration table 2, a support means 3 supported by the vibration table 2 so as to be vibratable in the horizontal direction, a hopper 4 supported by the support means 3 into which a sample is introduced, a shutter 5 for opening and closing the discharge port of the hopper 4, and a container 6 placed on the vibration table 2 for receiving the sample dropped from the hopper 4. Since the hopper 4 contains a smaller amount of sample than in the case of the durum test, even if the sample dropped from the hopper 4 is received by the container 6 placed on the vibration table 2, it does not substantially affect the vibration of the vibration table 2.

[0012] The vibration table 2, also called a vibration table, includes a main body and a top plate that is supported so as to be vibratable with respect to the main body and on which an object can be placed, and is a device that vibrates the top plate in the horizontal direction by a motor. The horizontal vibration is a translational vibration that reciprocates on a straight line extending in the horizontal direction.

[0013] The support means 3 is a means that is fixed to the top plate of the shaking table 2 and moves integrally with the top plate while supporting the hopper 4. The support means 3 is formed, for example, so as to form a space inside, and supports the hopper 4 on the upper side. The support means 3 is provided with a flange on the lower side, for example, and the flange is detachably attached to the top plate by a clamp (not shown). The clamp is provided with a screw, for example, and the support means 3 can be attached to and detached from the shaking table 2 by loosening this screw. The support means 3 is a box-shaped structure having a door (not shown) that can be opened and closed on the front side, for example. By opening the door on the front side of the box-shaped structure, the container 6 can be taken in and out of the support means 3.

[0014] The hopper 4 is a container formed in a conical shape and provided with a circular discharge port on the lower side. The hopper 4 is formed of a metal material, for example, stainless steel. The inclination angle of the hopper 4 is within the range of 30° to 60°, preferably within the range of 40° to 50°, and is 45° as an example. The inclination angle is the angle (gradient) of the wall surface of the hopper 4 with respect to the horizontal direction. The inner diameter of the discharge port is within the range of 40 mm to 80 mm, preferably within the range of 50 mm to 70 mm, and is 60 mm as an example. The depth of the hopper 4 is set according to the amount of sample used in the adhesion evaluation test, and is within the range of 100 mm to 300 mm, preferably within the range of 100 m to 200 mm, and is 160 mm as an example.

[0015] The shutter 5 is an example of an opening and closing means for opening and closing the discharge port of the hopper 4. The shutter 5 can be operated by the user on the hand side, and can be moved between a position where it covers the discharge port of the hopper 4 from below and closes it and a position where it opens the discharge port of the hopper 4.

[0016] The container 6 is, for example, a cylindrical container. The container 6 is arranged inside the internal space of the support means 3 and is placed so as not to shift with respect to the top plate of the shaking table 2. For example, anti-slip rubber may be provided on the back surface of the container 6. The above is the configuration of the test apparatus 1.

[0017] Next, with reference to FIG. 2, the flow of the method for evaluating the adhesiveness of coal using the test apparatus 1 according to the embodiment will be described. First, a sample of the coal type to be tested is prepared (step S1). The sample is, for example, coal that has passed through a sieve within a range of 1 mm to 10 mm in mesh size, preferably coal that has passed through a sieve within a range of 1 mm to 4 mm in mesh size, more preferably coal that has passed through a sieve within a range of 2 mm to 3 mm in mesh size, and as an example, coal that has passed through a 2.8 mm sieve. The mesh size of the sieve is the actual size of the mesh. For example, in the case of a sieve with wire rods intersecting vertically and horizontally, it is the dimension of the gap portion of each mesh.

[0018] The sample amount is, for example, within a range of 100 g to 2 kg, preferably within a range of 400 g to 600 g, and as an example, 500 g. As the sample, either wet coal or dry coal may be used, but since wet coal may have high adhesiveness due to the moisture content, it is preferable to use dried dry coal. The dry coal can be obtained by exposing the coal to wind or outside air or by storing it in a thermostatic chamber and holding it in a state where the temperature is raised.

[0019] Also, at the time of step S1, it is advisable to measure or know the moisture content of the sample. The moisture content may be any of the adhering moisture, total moisture, and fixed moisture, but considering the relevance to the discharge time, it is preferable to use the total moisture. The adhering moisture is the remaining moisture content when heated at 40°C. The total moisture is the remaining moisture content when heated at 107°C based on the "5. Moisture Quantification Method" of JIS (Japanese Industrial Standards) M 8812 "Coals and Cokes - Industrial Analysis Methods". The inherent moisture is the remaining moisture content after drying at 107°C after removing the adhering moisture and is calculated by the following formula (1). Inherent moisture (%) = 100×(Total moisture (%) - Adhering moisture (%)) / (100 - Adhering moisture (%)) …(1)

[0020] As the sample, the dry coal used for moisture measurement of coal may be directly reused. The moisture measurement is performed, for example, by the loss on drying method. Since the sample used in the moisture measurement has already been sieved and dried, using such a sample eliminates the need for the preparation steps such as the reduction and drying required in the conventional durum test method. For moisture measurement of coal, for example, a sample that has passed through a sieve with an opening of 2.8 mm is used.

[0021] Next, an ejection time measurement step of measuring the ejection time of the sample from the hopper 4 of the test apparatus 1 is performed (step S2). Hereinafter, with reference to FIG. 3, the flow of the ejection time measurement step will be described.

[0022] First, the sample is charged into the hopper 4 (step S21). Next, preliminary vibration is applied for a certain preliminary vibration time (step S22). The purpose of applying preliminary vibration is to increase the bulk density of the sample. The vibration frequency is, for example, within the range of 100 cpm to 200 cpm, and as an example, the vibration frequency is about 200 cpm. The preliminary vibration time is, for example, within the range of 10 seconds to 300 seconds, and as an example, it is 10 seconds. Cpm is a unit indicating the number of vibration cycles per minute.

[0023] After the process of step S22 is completed, the shutter 5 is opened and vibration is applied again, and the ejection time when all of the sample in the hopper 4 is ejected from the ejection port is measured (step S23). As a specific procedure, the time may be measured with a stopwatch while visually observing the sample in the hopper 4. At this time, the vibration frequency is, for example, within the range of 100 cpm to 200 cpm, but it is preferably the same as the vibration frequency during preliminary vibration, and as an example, it is about 200 cpm.

[0024] Next, the container 6 is taken out from the shaking table 2, the sample that has fallen into the container 6 in the process of step S23 is collected (step S24), and the process returns to the process of FIG. 2. If a plastic bag is set in the container 6, the sample can be easily collected by simply taking out the plastic bag containing the sample from the container 6. The above is the flow of the ejection time measurement step.

[0025] Return to Fig. 2. After the completion of the discharge time measurement step (step S2), check whether the discharge time has been measured for all the water contents set for each sample (step S3). If the discharge time has been measured for all the water contents set for each sample (step S3; Yes), move to the step S5 process.

[0026] On the other hand, if the discharge time has not been measured for all the water contents set for each sample (step S3; No), adjust the water content of the sample recovered in the step S2 process (step S4), and return to the step S2 process. In the step S4 process, it is advisable to measure a certain amount of water, add this measured water to the recovered sample, and then cure the sample so that the water penetrates. The curing time may be, for example, 30 minutes. If the water content of the sample is measured in the step S1 process, the water content of the water-added sample can be easily calculated by simply measuring the water to be added to the sample, and re-measurement of the water content becomes unnecessary. By repeating such a process, the relationship between the water content of the sample and the discharge time can be obtained. The test method according to the embodiment is a method for obtaining the relationship between the water content of the sample and the discharge time by a series of processes of steps S1 to S4.

[0027] If Yes in the step S3 process, apply the test results to the evaluation criteria to evaluate the adhesion of the coal (step S5), and end all the processes. In the evaluation criteria, a plurality of categories with different adhesions are set based on the discharge time and the water content of the sample, and it is assumed that the longer the discharge time, the greater the adhesion. However, when the discharge time is longer than the first threshold value, the sample with a water content less than the second threshold value has a greater adhesion than the sample with a water content equal to or greater than the second threshold value. The evaluation criteria may be created based on the measurement results of the discharge time using a plurality of samples for which the adhesion is known in advance. When actually performing the adhesion evaluation, the test may be carried out under the same test apparatus configuration and the same vibration conditions as those used when creating the evaluation criteria. The vibration conditions are, for example, the vibration frequency, amplitude, pre-vibration time, etc.

[0028] To explain an example of the evaluation criteria, for example, as shown in Fig. 4, it is set in five levels from A to E according to the degree of adhesion. Evaluation A indicates the smallest adhesion and good dischargeability, while evaluation E indicates the largest adhesion and a high risk of trouble. When the discharge time is 200 seconds (the first threshold) or less, regardless of the total moisture content, it is evaluated as one of evaluations A to D according to the discharge time. When the discharge time is more than 200 seconds and the total moisture content is less than 16 wt% (the second threshold), it is evaluated as evaluation E, and when the discharge time is more than 200 seconds and the total moisture content is 16 wt% or more, it is evaluated as evaluation D. Note that the evaluation criteria are not limited to being divided into five levels. The above is the process of the coal adhesion evaluation method.

[0029] As described above, the test apparatus 1 according to the embodiment includes a shaking table 2 that generates horizontal vibration, a conical hopper 4 that is attached to the shaking table 2 so that the vibration from the shaking table 2 is transmitted, receives a coal sample from above, and drops it from the lower discharge port, a shutter 5 that opens and closes the discharge port of the hopper 4, and a container 6 that is placed on the shaking table 2 so as to be disposed below the hopper 4 and receives the sample dropped from the hopper 4. Therefore, by using a sample that has passed through a sieve within the range of 1 mm to 10 mm in aperture, it is possible to perform a simple test that can obtain an evaluation result equivalent to that of the drum test while suppressing the sample amount compared to the drum test. In addition, since the test apparatus 1 according to the embodiment is much smaller and more portable than the test apparatus used in the drum test, the coal adhesion evaluation can be easily performed for each lot even at a site such as a thermal power plant.

[0030] The present invention is not limited to the above embodiment, and the following modifications are also possible.

[0031] (Modification example) In the above embodiment, the support means 3 is a box-shaped member formed by combining a plurality of plate-like members, but the present invention is not limited to this. For example, the support means 3 may be configured by combining a plurality of tubular members.

[0032] In the above-described embodiment, the shutter 5 that can be operated on the user side was provided, but the present invention is not limited to this. For example, the shutter 5 may be driven by a motor, and the shutter 5 may be configured to open and close by controlling the rotation of the motor.

[0033] Further, the test apparatus 1 may further include a timer and a controller, and the controller may be configured to control the shaking table 2, the shutter 5, and the timer. Specifically, when the user turns on a switch provided on the controller, after the controller generates preliminary vibrations for a certain period of time, the motor releases the shutter 5, the shaking table 2 starts horizontal vibrations, and the timer may start timing. Also, when the controller detects that the dropping of all the samples from the hopper 4 is completed, the timing by the timer and the vibrations by the shaking table 2 may be stopped, and with reference to the adhesion evaluation criteria stored in the memory in advance, the adhesion category may be determined from the measurement time by the timer and output to the outside. To detect that the dropping of all the samples is completed, a weighing scale for measuring the weight of the hopper 4 may be provided in the test apparatus 1 to detect that the hopper 4 has become empty, or an optical sensor may be provided at the discharge port of the hopper 4 to detect the presence or absence of the sample.

[0034] In the above-described embodiment, anti-slip rubber was provided on the back surface of the container 6, but the present invention is not limited to this. For example, anti-slip rubber may be provided on the top plate of the shaking table 2, or a stopper for restraining the periphery of the container 6 may be provided. The stopper may be, for example, a circular ring.

[0035] In the above-described embodiment, the adhesion was evaluated for granular coal, but the present invention is not limited to this. The test apparatus 1 and the test method according to the embodiment may be used to evaluate the adhesion of granular materials other than coal.

[0036] The above embodiments are illustrative, and the present invention is not limited thereto. Various embodiments are possible without departing from the gist of the invention described in the claims. The constituent elements described in the embodiments and modifications can be freely combined. Also, inventions equivalent to the invention described in the claims are included in the present invention.

[0037] Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.

[0038] (Example 1) In Example 1, for wet coals of 48-mesh and 54-mesh, test conditions under which the adhesiveness can be evaluated with a smaller amount of sample than in the durum test were examined. 48-mesh is an example of wet coal with high adhesiveness, and 54-mesh is an example of wet coal with low adhesiveness. As samples, in addition to 48-mesh and 54-mesh, each coal type constituting 48-mesh and 54-mesh was used individually. Since wet coal that has passed through a 40-mm sieve is delivered to thermal power plants, this type of wet coal was used as a sample. Hereinafter, such a sample will be simply expressed as a "40-mm sieve-passed sample". The sample amount is 500 g, which is the target in this example. In consideration of the fact that the adhesiveness of coal increases as the moisture content increases and that water may be added to suppress heat generation in stored coal, the adhesiveness of the sample when water was added was also confirmed. The moisture content of the sample was taken as the adhering moisture (%).

[0039] First, a prototype was newly created to measure the discharge time when the sample was dropped from the hopper as shown in Fig. 5. The prototype includes a commercially available vibrating table, a hopper fixed to the vibrating table with a rubber ring and having a rubber stopper that can be attached and detached to the discharge port, and a cylindrical container that supports the hopper from below. Considering the ease of obtaining the hopper, the inclination angle was set to 45°. As a result of repeatedly examining the inner diameter of the discharge port in the range of 40 to 60 mm, it was decided to use a hopper with an inner diameter of the discharge port of 40 mm. The other dimensions of the hopper are a maximum inner diameter of 250 mm and a depth of 100 mm. As the test procedure, first, after a 500 g sample was put into the hopper, a preliminary vibration was applied for 10 seconds, then the rubber stopper was removed from the discharge port of the hopper to apply vibration, and the time from when the rubber stopper was removed until all of the sample was discharged from the discharge port was measured. As a result of repeatedly examining the vibration frequency in the range of 100 cpm to 200 cpm during the preliminary vibration and during the sample discharge, the vibration frequency was unified to 200 cpm.

[0040] The results are shown in Fig. 6. The 48-mesh powders are all mixed coals of domestic coals A coal, B coal, C coal, E coal, and F coal, and the 54-mesh powder is mainly made from D coal, which is a domestic coal. In Fig. 6, the unit of the discharge time is seconds. Since the test was terminated when 300 seconds had elapsed from the opening of the shutter regardless of the discharge situation, "300 seconds" in Fig. 6 indicates that the discharge time is 300 seconds or more. Also, "water addition + 3%" indicates that 3% wt of adhering moisture was added to the sample. Regarding the 48-mesh powder, it was confirmed that the discharge time from the discharge port was generally long and it had high adhesiveness. However, for the other coal types, no correlation was found between the amount of water added and the discharge time. This is considered to be because the proportion of lumps about several cm in diameter was large in the sample passing through the 40 mm sieve, and these lumps pushed out other parts of the sample or blocked the discharge port. It is also considered that the proportion of lumps in the entire sample changed depending on the sampling of the sample, and the results of the adhesiveness evaluation were not stable.

[0041] (Example 2) In Example 2, an adhesion evaluation test was conducted using a prototype machine for a 2.8 mm sieve-passed sample, which has a smaller diameter than that in Example 1. The reason is that there are no lumps with a diameter of about several centimeters in the 2.8 mm sieve-passed sample, so it has better uniformity compared to the 40 mm sieve-passed sample and good reproducibility for each sampling. In addition, the sieve opening was selected to be 2.8 mm because, as described above, a 2.8 mm sieve-passed sample is also used for moisture measurement of the sample.

[0042] The measurement results of the discharge time are shown in Fig. 7. The discharge time of the 54 powder without moisture adjustment was 13 seconds, while the discharge time of the 48 powder without moisture adjustment was more than 300 seconds. It was confirmed that the 48 powder has higher adhesiveness. Also, for other coal types, it was found that the discharge time tends to increase as the water addition amount increases. From the above, it was confirmed that when using the newly created test apparatus, the adhesiveness of coal can be evaluated well by using a 2.8 mm sieve-passed sample.

[0043] (Example 3) In Example 3, the 2.8 mm sieve-passed coal was dried at 40 °C using a constant temperature bath, and an adhesion evaluation test was carried out using a prototype machine for a sample obtained by adding a certain amount of water to the dried coal. This is because it is considered that the moisture content of the wet coal used in Example 2 was high and the discharge time became long. The curing time after adding water to the dried coal was set to 5 minutes. Other conditions were the same as those in Example 1.

[0044] The results are shown in Fig. 8. As expected, the discharge time generally became shorter compared to the case of Example 2. For the 48 powder and C coal with 10 wt% of adhering moisture added, the discharge time remained more than 300 seconds, and it was confirmed that they have particularly high adhesiveness.

[0045] (Example 4) In Example 4, a simple adhesion evaluation test (simple test) was performed on the dry coals of each coal type using a prototype machine, and the results were compared with the results of the drum test, which is a comparative example. Four types of coals, namely Coal A, Coal B, Coal C, and Coal G, were used as samples. Coal G is produced in Australia. Since Coal A was evaluated to have low adhesion in past tests, it was used as a control group.

[0046] As the procedure for the simple test, which is an example, first, the coal used as a sample was dried at a temperature of 40 °C using a thermostat to obtain dry coal. After applying preliminary vibration to the sample introduced into the prototype machine, the discharge time of the sample was measured. The preliminary vibration time was 10 seconds. Each time the measurement of the discharge time was completed, weighed water was added to the dry coal, and a test was carried out to measure the discharge time each time. Based on the results of Example 3, the curing time of the sample was set to 30 minutes. Also, in the previous example, the adhesion of the sample was evaluated using the adhering moisture, but it was found that the total moisture had a higher correlation with the discharge time, so the evaluation was made using the total moisture. Other conditions were the same as in the case of Example 1.

[0047] In the drum test, which is a comparative example, 12 kg of coal with preliminarily adjusted moisture was introduced into a stainless-steel hopper with an inclination angle of 45° into a test apparatus dedicated to the drum test. After applying preliminary vibration, the shutter at the bottom of the hopper was opened, and the time required for the total amount of coal to be discharged from the discharge port was measured. The sample was air-dried once, evenly watered, cured for 30 minutes, and then the test was carried out. Both the old drum test with a preliminary vibration time of 10 seconds and the new drum test with a preliminary vibration time of 300 seconds were performed. The moisture content was evaluated by the total moisture, and the total moisture of the sample was measured each time after watering. As a result, in both the old and new drum tests, Coal B and Coal C were evaluated as "high risk of trouble", and Coal G was evaluated as having "good" dischargeability.

[0048] The results of the simple test, which is an example, are shown in Fig. 9. In the simple test, the discharge time becomes longer as the total moisture content increases. Therefore, it is preferable to evaluate the adhesiveness based on the total moisture content when the discharge time suddenly becomes long. In the old and new Durham tests, the discharge time became shorter when the moisture content exceeded a certain level. However, in the simple test, the discharge time remained long even when the moisture content increased. This is because in the old and new Durham tests, when the moisture content increases, the fine powder of the sample becomes agglomerated and easily falls due to its weight. In the simple test, since the sample passing through a 2.8 mm sieve is used, it is considered that the sample remains light and is difficult to fall even when the moisture content is high.

[0049] The adhesiveness evaluation criteria in the simple test created with reference to the evaluation criteria of the old and new Durham tests are shown in Fig. 4 above. When the results of the simple test are applied to this evaluation criteria, B coal and C coal are considered to have "high risk of trouble" because the discharge time is 300 seconds or more at total moisture contents of 10.5 wt% and 13.9 wt% respectively. Also, for G coal, the dischargeability is "good" because the discharge time is 100 seconds or less at any total moisture content. For A coal, which is the control group, the dischargeability is "attention required" because the discharge time is 200 seconds or more at a total moisture content of 17.2 wt%.

[0050] From the above, it can be understood that the results of the simple test are equivalent to those of the old and new Durham tests. Comparing the two, the simple test is advantageous in that the sample volume is small, the preliminary vibration time is short (compared with the old Durham test), moisture measurement for each test section is not required, and the test apparatus is small and portable. Also, in the simple test, although coal screening is required, coal reduction is also required in the old and new Durham tests. Therefore, the time and labor required for sample preparation are almost the same for both.

[0051] (Example 5) In Example 5, an adhesion evaluation test was carried out using an improved prototype machine obtained by improving the prototype machine created in Example 1. In the prototype machine created in Example 1, the hopper and the shaking table were fixed with a rubber ring, whereas in the improved prototype machine, as shown in Fig. 10, the hopper is supported by a supporting means having a box-shaped main body, and a flange provided on the supporting means is detachably attached to the shaking table by a screw-type clamp.

[0052] The results are shown in Figs. 11 to 13. For B coal and C coal, the moisture content at which the adhesion increases in the new Durham test and the simple test was almost the same, but for G coal, there was a slight deviation in the moisture content at which the adhesion increases between the two. This is presumably because in the simple test, the sample is fine powder and light and difficult to fall. Nevertheless, for any coal type, an evaluation that the adhesion is low was obtained in light of the evaluation criteria in Fig. 4. From the above, it can be understood that even when using the improved prototype machine, the results of the simple test and the new Durham test are equivalent.

Explanation of reference numerals

[0053] 1 Test apparatus 2 Shaking table 3 Supporting means 4 Hopper 5 Shutter 6 Container

Claims

1. A test apparatus for evaluating the adhesiveness of granular materials, comprising: A shaking table that generates horizontal vibrations; A conical hopper that is attached to the shaking table so that vibrations from the shaking table are transmitted, receives a sample of the granular material from above, and drops it from a lower discharge port; Opening and closing means for opening and closing the discharge port of the hopper; A container that is placed on the shaking table so as to be disposed below the hopper and receives the sample that has fallen from the hopper. The test apparatus comprising the above components.

2. The inclination angle of the hopper is in the range of 30° to 60°, and the inner diameter of the discharge port of the hopper is in the range of 40 mm to 80 mm. The test apparatus according to Claim 1.

3. The depth of the hopper is in the range of 100 mm to 300 mm. The test apparatus according to Claim 2.

4. The test apparatus is attached to the top plate of the shaking table, is formed to form a space inside, and includes support means for supporting the hopper on the upper side. The container is placed on the shaking table so as to be disposed within the space of the support means. The test apparatus according to Claim 1.

5. The support means includes a flange on the lower surface side, and the flange is detachably attached to the top plate by a clamp. The test apparatus according to Claim 4.

6. A test method using the test apparatus according to any one of Claims 1 to 5, comprising: A loading step of loading the sample into the hopper; A preliminary vibration step of applying horizontal preliminary vibrations to the sample loaded into the hopper by the shaking table; A measurement step of applying horizontal vibrations to the sample to which the preliminary vibrations have been applied by the shaking table, opening the discharge port of the hopper, and measuring the discharge time from when the discharge port is opened until all of the sample is discharged. The test method including the above steps. The sample is granular material that has passed through a sieve with an aperture size in the range of 1 mm to 10 mm. The test method.

7. The granular material includes granular pulverized coal. The loading step is carried out after moisture measurement by drying the granular coal. The sample loaded into the hopper is the granular coal used in the moisture measurement. The test method according to Claim 6.

8. The test method further includes: A recovery step of recovering the sample after the measurement step. An adjustment step of adjusting the moisture content of the sample by adding and curing the water measured in the sample recovered in the recovery step; comprising; using the sample whose moisture content has been adjusted in the adjustment step, a series of steps including the charging step, the preliminary vibration step, and the measurement step are carried out again; The test method according to claim 6.

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