Heat generation evaluation device

Abstract

To provide a heat generation evaluation device which is easily portable and capable of evaluating the heat generation of a substance. [Solution] The evaluation device 1 comprises an insulated container 2, a reaction vessel 3 contained within the insulated container 2 and containing a coal sample, an air supply pipe 4 connected to the reaction vessel 3 through the insulated container 2 and supplying oxygen from an oxygen tank 4a into the reaction vessel 3, an exhaust pipe 5 connected to the reaction vessel 3 through the insulated container 2 and exhausting gas generated in the reaction vessel 3, and a heater 6 supported by the insulated container 2, the reaction vessel 3 or the air supply pipe 4 and heating the reaction vessel 3 and the air supply pipe 4.

Description

[Technical field]

[0001] The present invention relates to a heat generation evaluation device. [Background technology]

[0002] It is known that coal stored in a silo will spontaneously generate heat if certain conditions are met. In order to suppress spontaneous heat generation in coal, it is necessary to evaluate the heat generation property of each type of coal and take measures accordingly. In the evaluation of the heat generation property of coal, oxygen is supplied into a reaction vessel containing a coal sample, the temperature rise rate of the coal sample that has been allowed to spontaneously generate heat is measured, and the heat generation property of coal is evaluated based on this temperature rise rate. For example, Patent Document 1 discloses an evaluation device that evaluates the heat generation property of coal by placing a reaction vessel containing a coal sample in a thermostatic chamber and supplying heated oxygen to the reaction vessel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-66296 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the evaluation device of Patent Document 1, a reaction vessel is heated by a thermostatic bath, and either a gas supply pipe is placed in the thermostatic bath or a separate device for heating oxygen is used to heat the oxygen. For this reason, the evaluation device of Patent Document 1 requires the use of a thermostatic bath, which poses the problem that it cannot be easily carried around and cannot evaluate the heat generation property of coal in places where such equipment is not available. Such problems are not limited to the case of evaluating the heat generation property of coal, but also exist when evaluating the heat generation property of other substances.

[0005] The present invention has been made against this background, and has an object to provide a heat generation evaluation device that is easily portable and capable of evaluating the heat generation of a substance. [Means for solving the problem]

[0006] In order to achieve the above object, the heat generation evaluation device according to the present invention comprises: A thermal insulated container; A reaction vessel that is accommodated in the thermal insulation vessel and that accommodates a sample; an air supply pipe connected to the reaction vessel through the heat-insulating vessel and supplying oxygen from an oxygen supply source into the reaction vessel; an exhaust pipe connected to the reaction vessel through the heat-insulating vessel and configured to exhaust gas generated in the reaction vessel; a heater supported on the heat insulating container, the reaction container, or the air supply pipe, for heating the reaction container and the air supply pipe; Equipped with. Effect of the Invention

[0007] According to the present invention, it is possible to provide a heat generation evaluation device that is easily portable and capable of evaluating the heat generation of a substance. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an overall configuration of a heat generation evaluation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a specific configuration of an air supply pipe in the heat generation evaluation device according to the embodiment of the present invention. [Diagram 3] 1 is a flowchart showing the flow of a method for evaluating heat generation properties of coal according to an embodiment of the present invention. [Figure 4] 4 is a flowchart showing a flow of a temperature rise time measuring process according to the embodiment of the present invention. [Diagram 5] FIG. 2 is a photograph of the exterior of a prototype in the first embodiment. [Figure 6] FIG. 2 is a diagram showing test conditions in Examples 1 to 4. [Figure 7] 2 is a graph showing the results of a heat generation evaluation test in Example 1. [Figure 8] 1 is a graph showing the results of a heat generation evaluation test (condition 4) in Example 2. [Figure 9] 1 is a graph showing the results of a heat generation evaluation test (condition 5) in Example 2. [Figure 10] 1 is a graph showing the results of a heat generation evaluation test (condition 6) in Example 2. [Figure 11] 1 is a graph showing the results of a heat generation evaluation test in Example 3. [Figure 12] 1 is a graph showing the results of a heat generation evaluation test in Example 4. [Figure 13] 1 is a graph showing the results of a heat generation evaluation test carried out using a thermostatic chamber. [Figure 14] FIG. 13 is a photograph of the appearance of an improved prototype in Example 5. [Figure 15] 1 is a graph showing the results of a heat generation evaluation test in Example 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a heat generation evaluation device according to an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same or equivalent parts are given the same reference numerals. In the embodiment, a case where a coal sample is used as a sample to be subjected to a heat generation evaluation test will be described as an example.

[0010] The heat generation evaluation device according to the embodiment is a device that measures the time (heat-up time) required for a coal sample contained in a reaction vessel to spontaneously heat up and increase in temperature by continuously supplying oxygen to the coal sample. The user refers to evaluation criteria created in advance and evaluates the heat generation property of each coal type based on the heat-up time measured for each coal type. The longer the heat-up time, the lower the heat generation property of the coal is evaluated to be.

[0011] As a heat generation evaluation method, for example, the R70 method may be used. The R70 method is a method for evaluating the heat generation property of coal that is being considered for international standardization. In the R70 method, oxygen is supplied at a constant flow rate to a coal sample placed in an insulated container to promote spontaneous heat generation, and the heating time for the coal sample to heat up from the starting temperature of 40°C to the target temperature of 70°C is measured. The heat generation property of coal may then be evaluated based on this heating time.

[0012] The heat generation evaluation device according to the embodiment has the following configuration, and is small and portable, so that heat generation evaluation can be performed for each lot of coal at a site such as a thermal power plant. The configuration of the evaluation device 1 according to the embodiment will be described below with reference to Fig. 1 and Fig. 2. The evaluation device 1 is an example of a heat generation evaluation device.

[0013] As shown in FIG. 1, the evaluation device 1 includes an insulated container 2, a reaction vessel 3 that is contained within the insulated container 2 and that contains a coal sample, an air pipe 4 that is connected to the reaction vessel 3 through the insulated container 2 and that supplies oxygen into the reaction vessel 3, an exhaust pipe 5 that is connected to the reaction vessel 3 through the insulated container 2 and that exhausts gas generated in the reaction vessel 3, a heater 6 that is supported by the reaction vessel 3 and that heats the reaction vessel 3 and the air pipe 4, a thermometer 7 that is supported by the reaction vessel 3 and that measures the temperature of the coal sample (sample temperature) in the reaction vessel 3, a thermometer 8 that is supported by the air pipe 4 and that measures the temperature of oxygen in the air pipe 4 (oxygen temperature), and a control device 9 that is electrically connected to the heater 6, the thermometer 7, and the thermometer 8, and that controls the operation of the heater 6 based on the acidity temperature and the sample temperature.

[0014] The insulated container 2 is a container having thermal insulation properties, for example, a vacuum insulated container. The insulated container 2 includes a main body that houses the reaction container 3 and allows the reaction container 3 to be taken in and out through an opening, and a lid that is detachably attached to the opening of the main body and seals the main body. The lid of the insulated container 2 is provided with a through hole through which a thermometer 7 passes, and the main body of the insulated container 2 is provided with separate through holes through which an air supply pipe 4 and an exhaust pipe 5 pass.

[0015] The reaction vessel 3 is a cylindrical vessel that contains a coal sample. The reaction vessel 3 is a vessel having thermal insulation properties, for example, a vacuum insulated vessel. The reaction vessel 3 includes a main body that contains the coal sample therein, and a lid that is detachably attached to an opening of the main body and seals the main body. The lid is an example of an upper surface portion of the reaction vessel 3. The lid of the reaction vessel 3 is provided with individual through-holes through which the air supply pipe 4, the exhaust pipe 5, and the thermometer 7 pass, and the gaps between the air supply pipe 4, the exhaust pipe 5, and the thermometer 7 and each through-hole are sealed.

[0016] The air supply pipe 4 extends from the inside to the outside through the lid of the reaction vessel 3, and extends to the outside through the main body of the heat-insulating vessel 2. The air supply pipe 4 is connected to an oxygen tank 4a and a nitrogen tank 4b, and selectively supplies oxygen and nitrogen supplied from the oxygen tank 4a and the nitrogen tank 4b to the reaction vessel 3. The oxygen tank 4a is an example of an oxygen supply source, and the nitrogen tank 4b is an example of a nitrogen supply source. The oxygen tank 4a may contain a gas other than oxygen, which is the main component, and the nitrogen tank 4b may contain a gas other than nitrogen, which is the main component.

[0017] The air supply pipe 4 is a pipe extending from the reaction vessel 3 that branches midway, and an oxygen tank 4a and a nitrogen tank 4b are connected to each of the branched pipes. A switching valve 4c is provided at the branched portion of the air supply pipe 4, which can switch whether oxygen or nitrogen is supplied to the reaction vessel 3. Flow rate adjustment valves 4d and 4e that can be operated by the user and that adjust the flow of gas to a constant flow rate are provided at the outlet sides of the oxygen tank 4a and the nitrogen tank 4b. A flow meter 4f that measures the flow rate of the passing gas is provided downstream of the switching valve 4c in the air supply pipe 4.

[0018] 2, inside the reaction vessel 3, the gas supply pipe 4 includes an inlet pipe 41 through which gas is supplied, a spiral pipe 42 connected to the inlet pipe 41, arranged so as to surround the reaction vessel 3 in a spiral shape, and heated by a heater 6 arranged on the outside, and an outlet pipe 43 connected to the spiral pipe 42 and discharging gas from above the reaction vessel 3 into the inside of the reaction vessel 3. The inlet pipe 41 is supported by the heat-insulating vessel 2, and the outlet pipe 43 is supported by the reaction vessel 3.

[0019] The spiral tube 42 is disposed so as to crawl on the surface of the reaction vessel 3, and is an example of a heat transfer tube having thermal conductivity. The spiral tube 42 is formed of a tube formed of a material having high thermal conductivity, for example, a copper tube. The inlet tube 41 is connected to the lower side of the spiral tube 42, and the outlet tube 43 is connected to the upper side of the spiral tube 42. Therefore, in the spiral tube 42, gas is supplied from the lower side of the reaction vessel 3, and gas is discharged from the upper side of the reaction vessel 3. The spiral tube 42 is wound in a spiral shape around the periphery of the reaction vessel 3, and is heated by the heater 6 and also exchanges heat with the reaction vessel 3. The reaction vessel 3 has a larger heat capacity than the air supply tube 4, and therefore temperature fluctuations due to external factors are small. Since the air supply tube 4 has the above-mentioned configuration, the air supply tube 4 can be compactly laid around the reaction vessel 3, and the temperature of the oxygen flowing through the air supply tube 4 can be stably maintained. Since the spiral tube 42 is supported on both sides by the inlet pipe 41 and the outlet pipe 43, it does not need to be supported by other members, but may be supported, for example, by any of the insulated container 2, the reaction container 3, and the heater 6.

[0020] The exhaust pipe 5 is a pipe that discharges gas generated in the reaction vessel 3 to the outside. The exhaust pipe 5 discharges exhaust gas, such as CO and CO2, generated by spontaneous heat generation of coal in the reaction vessel 3 to the outside.

[0021] The heater 6 is disposed outside the reaction vessel 3 and the spiral tube 42, and heats the coal sample in the reaction vessel 3 and the oxygen flowing through the spiral tube 42. This allows the temperature of the coal sample once heated to be maintained even if the amount of the coal sample is small, and allows the natural heat generation in the coal sample to be sustained. The heater 6 is, for example, a rod-shaped heater. The rod-shaped heater is, for example, a heater in which a spirally wound heating wire is enclosed in a pipe and insulated with a material having excellent thermal conductivity and insulation properties. In order to heat the reaction vessel 3 uniformly, it is preferable to arrange multiple rod-shaped heaters at equal intervals around the periphery of the reaction vessel 3.

[0022] Thermometer 7 is an example of a first thermometer that measures the temperature of the coal sample. Thermometer 7 includes, for example, a thermocouple probe. The thermocouple probe is inserted into the inside of the coal sample and directly measures the temperature of the coal sample. The thermocouple probe is supported by the lid of reaction vessel 3, and is inserted into the coal sample from the tip side when the lid of reaction vessel 3 is set on the main body.

[0023] Thermometer 8 is an example of a second thermometer that measures the temperature of oxygen flowing through the air pipe 4. Thermometer 8 is provided, for example, on the outlet side of outlet pipe 43 of the air pipe 4, and measures the temperature of oxygen immediately before it is released.

[0024] Returning to Fig. 1, the control device 9 periodically acquires the sample temperature and oxygen temperature measured by the thermometers 7 and 8, records the changes over time in the sample temperature and oxygen temperature, and controls the operation of the switching valve 4c and the heater 6 based on the sample temperature and oxygen temperature. The control device 9 includes, for example, a controller and a recorder. The controller is electrically connected to the heater 6 and the thermometers 7 and 8, and the recorder is communicatively connected to the controller.

[0025] The recorder acquires the sample temperature and oxygen temperature measured by the thermometers 7 and 8 via the controller, and stores the sample temperature and oxygen temperature in association with the measurement date and time. The recorder also includes a memory for storing a preset start temperature and target temperature, and a timer for counting time, and counts the heating time from when the sample temperature reaches the start temperature to when it reaches the target temperature.

[0026] The controller includes a memory and a processor, and the processor executes a program stored in the memory to control the operation of the heater 6 so that the oxygen temperature follows the sample temperature. Specifically, the controller periodically calculates the difference between the oxygen temperature and the sample temperature, and operates the heater 6 so that the difference between the oxygen temperature and the sample temperature becomes zero. For temperature control, for example, PID (Proportional Integral Differential) control is used. When the sample temperature reaches a preset target temperature, the controller controls the operation of the switching valve 4c so as to switch the supply gas supplied from the gas supply tube 4 to the reaction vessel 3 from oxygen to nitrogen, and terminates the operation of the heater 6. The evaluation device 1 has the above configuration.

[0027] Next, the flow of a method for evaluating the heat generation properties of coal using the evaluation device 1 according to the embodiment will be described with reference to FIG. First, a coal sample of the target coal type is prepared (step S1). Specifically, first, the coal is dried to obtain dry coal. For drying the coal, for example, vacuum drying may be performed. Next, the dry coal is sieved using a sieve. The mesh size of the sieve is in the range of 0.1 mm to 1 mm, which is merely an example.

[0028] Next, a temperature rise time measurement step is carried out to measure the temperature rise time, which is the time it takes for the temperature of the coal sample to rise from the starting temperature to the target temperature due to spontaneous heating (step S2). The starting temperature is set, for example, in the range of 30°C to 50°C, and the target temperature in the range of 60°C to 80°C. When the R70 method is used as the heat generation evaluation method, the starting temperature is set to 40°C, and the target temperature is set to 70°C. The flow of the temperature rise time measurement step will be described below with reference to FIG. 4.

[0029] Next, the coal sample is placed in the reaction vessel 3 (step S21). The amount of the sample is, for example, within a range of 150 g to 200 g, taking into consideration the size of the reaction vessel 3. Note that, since pre-heating is unlikely to occur when the sample temperature is low, if the coal sample has been stored in a refrigerator after sieving, it is desirable to pre-warm the sample to at least room temperature, preferably to 25°C to 30°C.

[0030] Next, oxygen supply to the reaction vessel 3 is started at a constant flow rate (step S22). The flow rate control valves 4d and 4e are opened and the switching valve 4c is set to the oxygen inflow side to start the oxygen supply. When oxygen supply to the reaction vessel 3 at an appropriate flow rate is started, the coal sample starts to generate spontaneous heat, and the sample temperature gradually rises. The oxygen flow rate is set, for example, within a range of 70 mL / min to 100 mL / min, taking into consideration the heating performance of the heater 6, the insulating performance of the insulating vessel 2 and the reaction vessel 3, and the amount of the coal sample. If the oxygen flow rate is low, the amount of oxygen required for the coal sample to generate spontaneous heat will be insufficient, and if the oxygen flow rate is too high, heat will be taken from the coal sample to the oxygen, and the sample temperature will drop.

[0031] At the time of starting the oxygen supply, the user activates the controller and recorder of the control device 9 in advance. The controller periodically acquires the sample temperature and oxygen temperature measured by the thermometers 7 and 8, and controls the operation of the heater 6 so that the oxygen temperature follows the sample temperature. This causes the oxygen flowing through the spiral tube 42 of the air supply pipe 4 to be heated by the heater 6, preventing low-temperature oxygen from flowing into the reaction vessel 3 and causing a drop in the sample temperature. The recorder also sequentially records the sample temperature periodically measured by the thermometer 7 in association with the measurement date and time, and starts counting the temperature rise time using a timer when the sample temperature reaches the starting temperature.

[0032] When the temperature of the coal sample rises to the target temperature due to spontaneous heating, the supply of oxygen to the reaction vessel 3 is stopped (step S23). At this time, the recorder stops counting the temperature rise time by the timer, and records the obtained temperature rise time in memory. The controller also supplies a control signal to the switching valve 4c of the air supply pipe 4, controls the operation of the switching valve 4c so that the supply gas is switched from oxygen to nitrogen, and terminates the operation of the heater 6. By switching the supply gas to nitrogen, oxygen necessary for the chemical reaction of the coal sample is discharged, and spontaneous heating of the coal sample in the reaction vessel 3 can be suppressed.

[0033] Next, the coal sample is removed from the reaction vessel 3 (step S24), and all steps in the temperature rise time measurement process are completed. The above is the flow of the temperature rise time measurement process.

[0034] Returning to FIG. 3, the heat generation property of coal is evaluated based on the heating time measured in the process of step S2 (step S3). The heat generation property of coal is evaluated relative to other coal types, and for example, the degree of heat generation property may be classified based on evaluation criteria that are preset to suit the evaluation device 1. The longer the heating time of a coal sample, the less likely the coal type corresponding to that sample is to generate spontaneous heat. For coal types with high heat generation property, it is advisable to monitor the coal temperature and the degree of steam generation, and to actively implement heat generation suppression measures. For example, the coal may be cooled by spraying water on it, or a cover may be placed on it to prevent air from entering. The above is the flow of the heat generation evaluation method.

[0035] As described above, the evaluation device 1 according to the embodiment includes the insulated container 2, the reaction container 3 that is housed in the insulated container 2 and contains a coal sample, the air supply pipe 4 that is connected to the reaction container 3 from the oxygen tank 4a through the insulated container 2 and supplies oxygen into the reaction container 3, the exhaust pipe 5 that is connected to the reaction container 3 through the insulated container 2 and exhausts gas generated in the reaction container 3, and the heater 6 that is supported by the reaction container 3 and heats the reaction container 3 and the air supply pipe 4. Therefore, there is no need to use a large-scale device such as a thermostatic bath, and it is possible to configure an easily portable heat generation evaluation device.

[0036] The present invention is not limited to the above-described embodiment, and the following modifications are possible.

[0037] (Modification) In the above embodiment, the coal sample is prepared by drying and sieving the coal, but the present invention is not limited to this. For example, depending on the state of the coal, drying and sieving may be omitted.

[0038] In the above embodiment, the thermometer 7 is passed through the lid of the insulated container 2, and the air supply pipe 4 and the exhaust pipe 5 are passed through the body of the insulated container 2, but the present invention is not limited to this. The thermometer 7 may be passed through the body of the insulated container 2, and either the air supply pipe 4 or the exhaust pipe 5 may be passed through the lid of the insulated container 2.

[0039] In the above embodiment, the air supply pipe 4, the exhaust pipe 5, and the thermometer 7 are passed through the lid of the reaction vessel 3, but the present invention is not limited to this. Any of the air supply pipe 4, the exhaust pipe 5, and the thermometer 7 may be passed through the main body of the reaction vessel 3.

[0040] In the above embodiment, the reaction vessel 3 has a cylindrical shape, but the present invention is not limited to this. For example, the reaction vessel 3 may be a spherical vessel.

[0041] In the above embodiment, the heat transfer tube of the air supply pipe 4 to which the heat from the heater 6 is transferred is the spiral tube 42, but the present invention is not limited to this. The heat transfer tube may be arranged in a form other than a winding manner as long as it is arranged so as to crawl on the surface of the reaction vessel 3, and may be configured to move up and down while shifting its position in the circumferential direction around the peripheral surface of the reaction vessel 3.

[0042] In the above embodiment, the heater 6 is disposed outside the spiral tube 42, but the present invention is not limited to this. For example, the heater 6 may be disposed inside the spiral tube 42, and the reaction vessel 3 and the heater 6 may be surrounded by the spiral tube 42.

[0043] In the above embodiment, the heater 6 is disposed outside the reaction vessel 3, but the present invention is not limited to this. For example, the heater 6 may be embedded in the reaction vessel 3. Also, in the above embodiment, the heater 6 is supported by the reaction vessel 3, but the present invention is not limited to this. The heater 6 may be supported by the insulating vessel 2 or the air pipe 4, for example.

[0044] In the above embodiment, a rod-shaped heater is used as the heater 6, but the present invention is not limited to this. For example, a ribbon heater may be used as the heater 6. In this case, it is preferable that the ribbon heater is wound around the circumferential surface of the reaction vessel 3. The ribbon heater and the helical tube 42 may be wound at the same pitch so as to be alternately arranged with each other.

[0045] In the above embodiment, a thermocouple is used as the thermometer 7, but the present invention is not limited to this. For example, a non-contact thermometer that measures the temperature of the coal sample may be used as the thermometer 7. Also, in the above embodiment, the temperature of the coal sample is measured directly, but the present invention is not limited to this. For example, the temperature of the gas or the temperature of the wall surface in the reaction vessel 3 may be measured, and the measured temperature may be regarded as the temperature of the coal sample.

[0046] In the above embodiment, PID control is performed on the heater 6 based on the difference between the oxygen temperature and the sample temperature so that the oxygen temperature follows the sample temperature, but the present invention is not limited to this. Proportional control or ON / OFF control may be performed on the heater 6 based on the difference between the oxygen temperature and the sample temperature.

[0047] In the above embodiment, the control device 9 includes a controller and a recorder, but the present invention is not limited to this. For example, instead of the recorder, a general-purpose computer having installed thereon a program capable of acquiring data from the thermometer and performing various processes may be used. Also, in the above embodiment, the evaluation device 1 includes the thermometers 7 and 8 and the control device 9, but the present invention is not limited to this. For example, if the sample temperature and oxygen temperature can be measured by an external device and the operation of the heater 6 can be controlled based on these, the thermometers 7 and 8 and the control device 9 may be omitted.

[0048] In the above embodiment, the heat generation property of coal is evaluated using the evaluation device 1, but the present invention is not limited to this. The evaluation device 1 may be used to evaluate the heat generation property of fuel other than coal, for example, a bimass fuel.

[0049] The present invention will be specifically described below with reference to examples, although the present invention is not limited to these examples.

[0050] Example 1 In Example 1, a prototype was created that allows a heat generation evaluation test to be performed using a small amount of sample, and a heat generation evaluation test of coal was performed in accordance with the R70 method.

[0051] First, a simple prototype was created by assembling available parts shown in Fig. 5. In the prototype, each part was assembled so as to have the same configuration as the evaluation device 1 according to the embodiment. A ribbon heater was wrapped around the reaction vessel (vacuum insulated vessel), an oxygen supply pipe and an exhaust pipe were connected to the upper side of the reaction vessel, and an oxygen / nitrogen switching valve and a flow meter were attached to the oxygen supply pipe. A controller was connected to the ribbon heater, and the ribbon heater was controlled so that the oxygen temperature followed the sample temperature.

[0052] The test conditions are as shown in FIG. 6. In Example 1, a test was carried out using the prototype machine described above to confirm whether coal would spontaneously heat up. A coal type that is prone to heat up was used as the sample. Hereinafter, this coal type is referred to as coal A. The sample was crushed with an electric mill for about 30 seconds, vacuum dried at a temperature of 70°C for about 24 hours, and refrigerated once. The sample was not sieved. In condition 1, 150g of the sample was kept cold, in condition 2, 20g of the sample was returned to room temperature, and in condition 3, 200g of the sample was heated to about 30°C, and a heat generation evaluation test was carried out for each. The test procedure was as follows: the sample was placed in a reaction vessel, oxygen was fed at a flow rate of 50mL / min, and the coal temperature was measured every minute with a thermocouple. The large vessel in FIG. 6 is an insulated vessel with an opening of 4cm and a height of 15.4cm, and the small vessel is an insulated vessel with an opening of 4cm and a height of 12cm. The small container was used to confirm whether the heat generation could be evaluated even with a reduced amount of sample.

[0053] The results are shown in Figure 7. Under all conditions 1 to 3, spontaneous heating occurred slowly, and the sample temperature did not reach 40°C. It was confirmed that spontaneous heating is less likely to occur if the sample is tested while refrigerated, and that it is better to warm the refrigerated sample to approximately room temperature beforehand, or to conduct the test while the residual heat from the vacuum drying remains.

[0054] Example 2 In Example 2, it was verified whether the spontaneous heating of coal is promoted by using a sieved sample of dry coal. The sample used was one that had been refrigerated once and then warmed to 30°C. The dry coal was sieved using a sieve with a mesh size of 212 μm. In addition to coal A, coal B and coal C, which are from different origins than coal A, were used under conditions 4 to 6 shown in FIG. 6. The sample weights were all standardized at 200 g. The other conditions were the same as those in Example 1.

[0055] The results are shown in Figures 8 to 10. Under condition 4, it took more than 50 hours for the sample temperature to finally reach 70°C or higher. Under condition 5, the test was stopped midway because no signs of the sample generating heat were observed. Under condition 6, the sample temperature repeatedly rose and fell, so when the oxygen flow rate was increased to 70 mL / min about 90 hours after the start of the test, the sample temperature rose smoothly. From the above, it was confirmed that an oxygen supply above a certain flow rate is necessary to maintain the spontaneous heating of coal.

[0056] Example 3 In Example 3, it was verified whether the sample amount could be reduced compared to Example 2 in the heat generation evaluation test. Under conditions 7 and 8 shown in Figure 6, coal A and coal C were used, respectively, and the sample amount was reduced from 200g to 150g. Under condition 9, a sample of coal A was placed in a small container. The sample amount was reduced to 18g. The other conditions were the same as those in Example 1. Note that "no refrigerated storage" in Figure 6 indicates that the test was carried out immediately after the coal was vacuum dried.

[0057] The results are shown in Figure 11. Under conditions 7 and 8, good results were obtained with no irregular increases or decreases in temperature. The reason why heat generation at low temperatures was gradual under condition 8 is because the sample temperature was relatively high at the start of the test. Under condition 9, it took several times longer for the sample to heat up to the same temperature compared to the test under condition 7. From the above, it was confirmed that if the sample amount is too small, it is difficult to maintain the temperature required for natural heating of the sample.

[0058] Example 4 In Example 4, based on the results of the previous Examples, 150 g of sample was used that had been vacuum dried, sieved using a sieve with 212 μm mesh, and adjusted to a temperature of 30° C. The oxygen flow rate was 70 mL / min. In conditions 10 to 13 shown in FIG. 6, in addition to coal B, coal C, and coal A, another coal type (coal D) that is considered to be less prone to spontaneous heating was used.

[0059] The results are shown in Figure 12. These results are comparable to the results of the heat generation evaluation test (comparative example) conducted using a thermostatic chamber shown in Figure 13. From the above, it was confirmed that the heat generation property of coal can be correctly evaluated using the prototype created in Example 1.

[0060] Example 5 In Example 5, an improved prototype having the same configuration as the evaluation device 1 according to the embodiment was created. The improved prototype was improved to be small and portable as shown in FIG. 14. The heat-insulating container was a box-shaped container that could be sealed, and the reaction container inside the heat-insulating container had the same configuration as the small container of the prototype described above. An oxygen supply pipe, an exhaust pipe, and a thermocouple probe were attached to the lid of the reaction container. The reaction container was configured so that the sample could be placed in the reaction container after removing the lid, and the lid could be set while inserting the thermocouple probe. Two rod-shaped heaters with a voltage of 100 V and an output of 104 W were attached to the reaction container. The other conditions were the same as those of Example 4.

[0061] When the test results using the improved testing device were compared with those using a thermostatic chamber, it was found that the heat generation curves at sample temperatures of 40°C to 70°C were nearly identical, as shown in Figure 15. Furthermore, when the heating rates at sample temperatures of 40°C to 70°C were calculated and compared, similar results were obtained. From the above, it was confirmed that coal heat generation evaluation tests using the improved evaluation device can obtain results similar to those obtained using a thermostatic chamber.

[0062] The above-mentioned embodiments are merely examples, and the present invention is not limited to these, and various embodiments are possible without departing from the spirit of the invention described in the claims. The components described in the embodiments and modifications can be freely combined. In addition, inventions equivalent to the inventions described in the claims are also included in the present invention. [Explanation of symbols]

[0063] 1. Evaluation device 2. Insulated container 3 Reaction vessel 4 Air pipe 42 Spiral tube 5. Exhaust pipe 6 Heater 7,8 Thermometer 9. Control Device

Claims

1. A thermal insulated container; A reaction vessel that is accommodated in the thermal insulation vessel and that accommodates a sample; an air supply pipe connected to the reaction vessel through the heat-insulating vessel and supplying oxygen from an oxygen supply source into the reaction vessel; an exhaust pipe connected to the reaction vessel through the heat-insulating vessel and configured to exhaust gas generated in the reaction vessel; a heater supported on the heat insulating container, the reaction container, or the air supply pipe, for heating the reaction container and the air supply pipe; A heat generation evaluation device comprising:

2. A portion of the air supply pipe is disposed so as to extend along the surface of the reaction vessel, The heater heats the reaction vessel and a portion of the air supply pipe that is disposed so as to extend along the surface of the reaction vessel. The heat generation evaluation device according to claim 1 .

3. a part of the air supply pipe is a helical pipe wound in a helical shape around a peripheral portion of the reaction vessel, The heater heats the peripheral surface portion and the spiral tube of the reaction vessel. The heat generation evaluation device according to claim 2 .

4. The oxygen supply source and the reaction vessel are connected to the spiral tube so that oxygen flows from the lower side to the upper side of the reaction vessel. The heat generation evaluation device according to claim 3 .

5. a first thermometer supported by the reaction vessel for measuring a temperature of the sample in the reaction vessel; a second thermometer supported on the air pipe for measuring the temperature of oxygen flowing through the air pipe; a control device electrically connected to the heater, the first thermometer, and the second thermometer, and configured to control an operation of the heater so that the oxygen temperature measured by the second thermometer follows the temperature of the sample measured by the first thermometer; Further comprising: The heat generation evaluation device according to claim 1 .

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