Evaluation device for exothermic property

Abstract

To provide an evaluation device for an exothermic property, capable of easy carrying and evaluating the exothermic property of a substance.SOLUTION: An evaluation device 1 includes an insulated container 2, a reaction container 3 that is housed in the insulated container 2 and that houses a coal sample, an air supply pipe 4 that is connected to the reaction container 3 through the insulated container 2 and that supplies oxygen from an oxygen tank 4a into the reaction container 3, an exhaust pipe 5 that is connected to the reaction container 3 through the insulated container 2 and that exhausts gas generated in the reaction container 3, and a heater 6 that is supported by the insulated container 2, the reaction container 3, or the air supply pipe 4 and that heats the reaction container 3 and the air supply pipe 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an exothermic property evaluation device.

Background Art

[0002] When coal stored in a silo satisfies certain conditions, a phenomenon of spontaneous heating is known. To suppress the spontaneous heating of coal, it is necessary to evaluate the exothermic property for each type of coal and take corresponding measures accordingly. In the evaluation of the exothermic property of coal, the temperature increase rate of a coal sample that is naturally heated by supplying oxygen into a reaction vessel containing the coal sample is measured, and the exothermic property of the coal is evaluated based on this temperature increase rate. For example, Patent Document 1 discloses an evaluation device that evaluates the exothermic property of coal by accommodating a reaction vessel containing a coal sample in a constant temperature bath and supplying heated oxygen to the reaction vessel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the evaluation device of Patent Document 1, while heating the reaction vessel with a constant temperature bath, the gas supply pipe is arranged in the constant temperature bath or oxygen is heated using a separate device for heating oxygen. Therefore, in the evaluation device of Patent Document 1, it is essential to use a constant temperature bath, and thus it cannot be easily carried around, and it is also impossible to evaluate the exothermic property of coal at a location without proper facilities. Such a problem exists not only when evaluating the exothermic property of coal but also when evaluating the exothermic property of other substances.

[0005] The present invention has been made based on such a background, and an object thereof is to provide a heat generation property evaluation device that can be easily carried and can evaluate the heat generation property of a substance.

Means for Solving the Problems

[0006] In order to achieve the above object, the heat generation property evaluation device according to the present invention includes: a heat insulation container, a reaction container housed in the heat insulation container and containing a sample, an air supply pipe connected to the reaction container through the heat insulation container and supplying oxygen into the reaction container from an oxygen supply source, an exhaust pipe connected to the reaction container through the heat insulation container and discharging the gas generated in the reaction container, a heater supported by the heat insulation container, the reaction container or the air supply pipe and heating the reaction container and the air supply pipe. It is provided with.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a heat generation property evaluation device that can be easily carried and can evaluate the heat generation property of a substance.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, the exothermicity evaluation apparatus according to the embodiment 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 embodiment, the case where a coal sample is used as a sample to be subjected to the exothermicity evaluation test will be described as an example.

[0010] The exothermicity evaluation apparatus according to the embodiment is an apparatus that measures the time (temperature rise time) required for the coal sample to spontaneously generate heat and increase in temperature by continuously supplying oxygen to the coal sample housed in the reaction vessel. The user refers to the pre-created evaluation criteria and evaluates the exothermicity of each coal type based on the measured temperature rise time for each coal type. The larger the temperature rise time, the lower the exothermicity of the coal is evaluated.

[0011] As a method for evaluating heat generation, for example, the R70 method may be used. The R70 method is a method for evaluating the heat generation of coal under consideration for international standardization. In the R70 method, natural heat generation is promoted by supplying oxygen at a constant flow rate to a coal sample in a heat-insulated container, and the temperature rise time is measured during which the coal sample rises in temperature from the starting temperature of 40°C to the target temperature of 70°C. Then, the heat generation of the coal may be evaluated based on this temperature rise time.

[0012] The heat generation evaluation apparatus according to the embodiment has the following configuration and is small and portable, so that heat generation evaluation can be carried out for each lot of coal at the site of a thermal power plant or the like. Hereinafter, with reference to FIGS. 1 and 2, the configuration of the evaluation apparatus 1 according to the embodiment will be described. The evaluation apparatus 1 is an example of a heat generation evaluation apparatus.

[0013] As shown in FIG. 1, the evaluation apparatus 1 includes a heat-insulated container 2, a reaction container 3 housed in the heat-insulated container 2 and containing a coal sample, an air supply pipe 4 connected to the reaction container 3 through the heat-insulated container 2 and supplying oxygen into the reaction container 3, an exhaust pipe 5 connected to the reaction container 3 through the heat-insulated container 2 and discharging the gas generated in the reaction container 3, a heater 6 supported by the reaction container 3 and heating the reaction container 3 and the air supply pipe 4, a thermometer 7 supported by the reaction container 3 and measuring the temperature (sample temperature) of the coal sample in the reaction container 3, a thermometer 8 supported by the air supply pipe 4 and measuring the temperature (oxygen temperature) of the oxygen in the air supply pipe 4, and a control device 9 electrically connected to the heater 6, the thermometer 7, and the thermometer 8 and controlling the operation of the heater 6 based on the oxygen temperature and the sample temperature.

[0014] The heat-insulated container 2 is a container having heat-insulating properties, for example, a vacuum heat-insulated container. The heat-insulated container 2 includes a main body that houses the reaction container 3 inside 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 heat-insulated container 2 is provided with a through-hole through which the thermometer 7 passes, and the main body of the heat-insulated container 2 is provided with individual through-holes through which the air supply pipe 4 and the exhaust pipe 5 pass.

[0015] The reaction vessel 3 is a cylindrical vessel for accommodating a coal sample. The reaction vessel 3 is a heat-insulating vessel, for example, a vacuum heat-insulating vessel. The reaction vessel 3 includes a main body for accommodating a coal sample therein, and a lid that is detachably attached to the opening of the main body and seals the main body. The lid is an example of the upper surface portion of the reaction vessel 3. The lid of the reaction vessel 3 is provided with individual through-holes through which each of the air supply pipe 4, the exhaust pipe 5, and the thermometer 7 penetrates, and the spaces between the air supply pipe 4, the exhaust pipe 5, the thermometer 7 and the respective through-holes are sealed.

[0016] The air supply pipe 4 extends from the inside to the outside through the lid of the reaction vessel 3 and further 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 as a main component, and the nitrogen tank 4b may contain a gas other than nitrogen as a main component.

[0017] The air supply pipe 4 branches midway through the pipe extending from the reaction vessel 3, and the oxygen tank 4a and the nitrogen tank 4b are respectively connected to the branched pipes. A switching valve 4c is provided at the branched portion of the air supply pipe 4 to switch between supplying oxygen and nitrogen to the reaction vessel 3. Flow rate adjustment valves 4d and 4e that are operable by the user and adjust the gas flow to a constant flow rate are provided on the outlet sides of the oxygen tank 4a and the nitrogen tank 4b. A flow meter 4f for measuring the flow rate of the gas passing therethrough is provided on the downstream side of the switching valve 4c in the air supply pipe 4.

[0018] As shown in FIG. 2, inside the reaction vessel 3, the air supply pipe 4 includes an inlet pipe 41 to which gas is supplied, a spiral pipe 42 that is connected to the inlet pipe 41 and is arranged to surround the reaction vessel 3 in a spiral shape and is heated by a heater 6 disposed on the outside, and an outlet pipe 43 that is connected to the spiral pipe 42 and discharges gas from above the reaction vessel 3 into 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 helical tube 42 is arranged to crawl on the surface of the reaction vessel 3 and is an example of a heat transfer tube having heat conductivity. The helical tube 42 is formed of a tube made of a material with high heat conductivity, for example, a copper tube. An inlet tube 41 is connected to the lower side of the helical tube 42, and an outlet tube 43 is connected to the upper side of the helical tube 42. Therefore, in the helical 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 helical tube 42 is spirally wound around the peripheral surface of the reaction vessel 3, is heated by the heater 6, and performs heat exchange with the reaction vessel 3. Since the reaction vessel 3 has a larger heat capacity than the air supply tube 4, temperature fluctuations due to external factors are small. Since the air supply tube 4 has the above configuration, the air supply tube 4 can be made to crawl compactly around the reaction vessel 3, and the temperature of the oxygen flowing through the air supply tube 4 can be stably maintained. Note that since the helical tube 42 is supported on both sides by the inlet tube 41 and the outlet tube 43, it does not need to be supported by other members, but may be supported by, for example, any of the heat insulation container 2, the reaction vessel 3, and the heater 6.

[0020] The exhaust pipe 5 is a pipe for discharging the gas generated in the reaction vessel 3 to the outside. The exhaust pipe 5 discharges, for example, exhaust gas generated by the natural heat generation of coal in the reaction vessel 3, for example, CO and CO2, to the outside.

[0021] The heater 6 is arranged outside the reaction vessel 3 and the helical tube 42, and heats the coal sample in the reaction vessel 3 and the oxygen flowing through the helical tube 42. Thereby, even if the sample amount of the coal sample is small, the temperature of the coal sample once heated can be maintained, and the natural heat generation in the coal sample can be sustained. The heater 6 is, for example, a rod-shaped heater. The rod-shaped heater is, for example, a heater in which a heating wire wound in a spiral shape is enclosed in a pipe and insulated with a material having excellent heat conductivity and insulation properties. In order to uniformly heat the reaction vessel 3, a plurality of rod-shaped heaters may be arranged at equal intervals around the peripheral surface of the reaction vessel 3.

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

[0023] The thermometer 8 is an example of a second thermometer that measures the temperature of the oxygen flowing through the air supply pipe 4. The thermometer 8 is provided, for example, on the outlet side of the outlet pipe 43 of the air supply pipe 4 to measure the temperature of the oxygen immediately before discharge.

[0024] Returning to FIG. 1, the control device 9 periodically acquires the sample temperature and the oxygen temperature measured by the thermometers 7 and 8, records the temporal changes in the sample temperature and the oxygen temperature, and controls the operations of the switching valve 4c and the heater 6 based on the sample temperature and the 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 communicably connected to the controller.

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

[0026] The controller includes a memory and a processor. By executing a program stored in the memory, the processor controls the operation of the heater 6 so that the oxygen temperature follows the sample temperature. Specifically, the difference between the oxygen temperature and the sample temperature is periodically calculated, and the heater 6 is operated so that the difference between the oxygen temperature and the sample temperature becomes zero. In temperature control, for example, PID (Proportional Integral Differential) control is used. Further, when the sample temperature reaches a preset target temperature, the controller controls the operation of the switching valve 4c to switch the supply gas supplied from the supply pipe 4 to the reaction vessel 3 from oxygen to nitrogen, and terminates the operation of the heater 6. The above is the configuration of the evaluation apparatus 1.

[0027] Next, with reference to FIG. 3, the flow of the coal calorific value evaluation method using the evaluation apparatus 1 according to the embodiment will be described. First, a coal sample of the target coal type is prepared (step S1). Specifically, first, the coal is dried to obtain dry coal. In the drying of coal, for example, vacuum drying may be performed. Next, the dry coal is sieved using a sieve. The mesh size of the sieve is, of course, just an example, and is in the range of 0.1 mm to 1 mm.

[0028] Next, a heating time measurement step of measuring the heating time, which is the time for the temperature of the coal sample to rise from the start temperature to the target temperature due to spontaneous heating, is performed (step S2). The start temperature is set, for example, within the range of 30°C to 50°C, and the target temperature is set within the range of 60°C to 80°C. When the R70 method is used as the calorific value evaluation method, the start temperature is set to 40°C and the target temperature is set to 70°C. Hereinafter, with reference to FIG. 4, the flow of the heating time measurement step will be described.

[0029] Next, the coal sample is accommodated in the reaction vessel 3 (step S21). The sample amount is, for example, in the range of 150 g to 200 g in consideration of the size of the reaction vessel 3. In addition, since preheating is less likely to occur when the sample temperature is low, if the coal sample is refrigerated after sieving, it is desirable to preheat the sample temperature to at least room temperature and preferably to 25°C to 30°C until it reaches room temperature.

[0030] Next, oxygen supply to the reaction vessel 3 is started at a constant flow rate (step S22). By opening the flow rate adjustment valves 4d and 4e and setting the switching valve 4c to the oxygen inflow side, the supply of oxygen is started. When the supply of oxygen into the reaction vessel 3 is started at an appropriate flow rate, the coal sample causes spontaneous heating and the sample temperature gradually rises. The oxygen flow rate is set within a range of, for example, 70 mL / min to 100 mL / min in consideration of the heating performance of the heater 6, the heat insulation performance of the heat insulation container 2 and the reaction vessel 3, and the sample amount of the coal sample. If the oxygen flow rate is low, the amount of oxygen required for the spontaneous heating of the coal sample is insufficient. If the oxygen flow rate is too high, heat is taken away from the coal sample by the oxygen, and the sample temperature decreases.

[0031] At the time of starting the oxygen supply, the user starts the controller and the recorder of the control device 9 in advance. The controller periodically acquires the sample temperature and the 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. As a result, the oxygen flowing through the spiral tube 42 of the air supply pipe 4 is heated by the heater 6, so that low-temperature oxygen can be prevented from flowing into the reaction vessel 3 and the sample temperature can be prevented from decreasing. Further, the recorder sequentially records the sample temperature periodically measured by the thermometer 7 in association with the measurement date and time, and starts counting the temperature increase time by the 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 increase time by the timer and records the obtained temperature increase time in the memory. Further, the controller 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, the oxygen required for the chemical reaction of the coal sample is discharged, and the spontaneous heating of the coal sample in the reaction vessel 3 can be suppressed.

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

[0034] Returning to FIG. 3, the calorific value of the coal is evaluated based on the heating time measured in the step of S2 (step S3). The calorific value of the coal is a relative evaluation among different coal types. For example, the degree of calorific value may be classified based on the evaluation criteria preset to conform to the evaluation apparatus 1. The longer the heating time of the coal sample, the more difficult it is to evaluate that spontaneous heating occurs in the coal type corresponding to the sample. For coal types with a high calorific value, it is advisable to monitor the temperature of the coal and the degree of generation of water vapor, and actively implement measures to suppress heat generation. For example, the coal may be cooled by spraying water, or covered to prevent the intrusion of air. The above is the flow of the calorific value evaluation method.

[0035] As described above, the evaluation apparatus 1 according to the embodiment includes a heat insulation container 2, a reaction container 3 housed in the heat insulation container 2 and containing a coal sample, an air supply pipe 4 connected from an oxygen tank 4a through the heat insulation container 2 to the reaction container 3 for supplying oxygen into the reaction container 3, an exhaust pipe 5 connected from the reaction container 3 through the heat insulation container 2 for discharging the gas generated in the reaction container 3, and a heater 6 supported by the reaction container 3 for heating the reaction container 3 and the air supply pipe 4. Therefore, it is not necessary to use a large-scale apparatus such as a thermostatic bath, and a calorific value evaluation apparatus that can be easily carried can be configured.

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

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

[0038] In the above-described embodiment, the thermometer 7 was passed through the lid of the heat-insulating container 2, and the air supply pipe 4 and the exhaust pipe 5 were passed through the main body of the heat-insulating container 2. However, the present invention is not limited to this. The thermometer 7 may be passed through the main body of the heat-insulating container 2, or either the air supply pipe 4 or the exhaust pipe 5 may be passed through the lid of the heat-insulating container 2.

[0039] In the above-described embodiment, the air supply pipe 4, the exhaust pipe 5, and the thermometer 7 were passed through the lid of the reaction vessel 3. However, the present invention is not limited to this. Any one 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-described embodiment, the reaction vessel 3 was cylindrical. However, the present invention is not limited to this. For example, the reaction vessel 3 may be a spherical container.

[0041] In the above-described embodiment, the heat transfer pipe through which heat from the heater 6 is transferred in the air supply pipe 4 was the spiral pipe 42. However, the present invention is not limited to this. As long as the heat transfer pipe is arranged so as to crawl on the surface of the reaction vessel 3, it may be in a form other than winding. For example, it may be configured to reciprocate up and down while shifting the position in the circumferential direction on the circumferential surface of the reaction vessel 3.

[0042] In the above-described embodiment, the heater 6 was arranged outside the spiral pipe 42. However, the present invention is not limited to this. For example, the heater 6 may be arranged inside the spiral pipe 42, and the reaction vessel 3 and the heater 6 may be configured to be surrounded by the spiral pipe 42.

[0043] In the above-described embodiment, the heater 6 was arranged outside the reaction vessel 3. However, the present invention is not limited to this. For example, the heater 6 may be embedded in the reaction vessel 3. Further, in the above-described embodiment, the heater 6 was supported by the reaction vessel 3. However, the present invention is not limited to this. The heater 6 may be supported by, for example, the heat-insulating container 2 or the air supply pipe 4.

[0044] In the above-described embodiment, a rod heater was 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. At this time, it is preferable to wind the ribbon heater around the peripheral surface of the reaction vessel 3. The ribbon heater and the spiral tube 42 may be wound at the same pitch so as to be arranged alternately with each other.

[0045] In the above-described embodiment, a thermocouple was used in 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. Further, in the above-described embodiment, the temperature of the coal sample was directly measured, but the present invention is not limited to this. For example, the temperature of the gas or 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-described embodiment, PID control was performed on the heater 6 based on the deviation between the two 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 deviation between the oxygen temperature and the sample temperature.

[0047] In the above-described 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 installed with a program capable of acquiring data of the thermometer and performing various processes may be used. Further, in the above-described 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 the 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-described embodiment, the calorific value of coal was evaluated using the evaluation device 1, but the present invention is not limited to this. The calorific value of fuels other than coal, for example, bismuth fuel, may be evaluated using the evaluation device 1.

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

[0050] (Example 1) In Example 1, a prototype machine capable of conducting a heat generation evaluation test with a small amount of sample was fabricated, and a heat generation evaluation test of coal compliant with the R70 method was conducted.

[0051] First, the available components shown in FIG. 5 were assembled to fabricate a simple prototype machine. In the prototype machine, each component was assembled so as to have the same configuration as the evaluation apparatus 1 according to the embodiment. A ribbon heater was wound 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 to control the ribbon heater 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 conducted using the above prototype machine to confirm whether the coal generates heat spontaneously. As the sample, a coal type that easily generates heat was used. Hereinafter, this coal type will be referred to as Coal A. The sample was pulverized with an electric mill for about 30 seconds, vacuum dried at a temperature of 70° C. for about 24 hours, and then used after being refrigerated once. The sample was not sieved. In Condition 1, 150 g of the sample was kept cold, in Condition 2, 20 g of the sample was returned to room temperature, and in Condition 3, 200 g of the sample was heated to about 30° C., and a heat generation evaluation test was conducted for each. As the test procedure, the sample was placed in the reaction vessel, oxygen was supplied at a flow rate of 50 mL / min, and the coal temperature was measured every minute with a thermocouple. Note that the large container in FIG. 6 is a heat-insulated container with an opening of 4 cm and a height of 15.4 cm, and the small container is a heat-insulated container with an opening of 4 cm and a height of 12 cm. The small container was used to confirm whether the heat generation property could be evaluated even when the amount of the sample was reduced.

[0053] The results are shown in Fig. 7. In any of Conditions 1 to 3, the spontaneous heating was slow and the sample temperature did not reach 40°C. It was confirmed that when the test is carried out with the sample kept refrigerated, spontaneous heating is less likely to occur, and it is advisable to preheat the refrigerated sample to about room temperature or to conduct the test with the residual heat from vacuum drying remaining.

[0054] (Example 2) In Example 2, it was verified whether the spontaneous heating of coal is promoted by using a sample obtained by sieving dry coal. As the sample, one that had been refrigerated once and warmed to 30°C was used. The sieving of the dry coal was carried out using a sieve with an opening size of 212 μm. In Conditions 4 to 6 shown in Fig. 6, in addition to Coal A, Coal B and Coal C from different production areas from Coal A were used respectively. The sample amount was unified to 200 g in all cases. Other conditions were the same as those in Example 1.

[0055] The results are shown in Figs. 8 to 10. In Condition 4, it took more than 50 hours for the sample temperature to finally reach 70°C or higher. In Condition 5, since no sign of heat generation in the sample was observed, the test was aborted halfway. In Condition 6, since the sample temperature repeated up and down, 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 in order to maintain the spontaneous heating of coal, an oxygen supply of a certain flow rate or more is necessary.

[0056] (Example 3) In Example 3, it was verified whether the sample amount can be reduced compared to the case of Example 2 in the exothermicity evaluation test. In Conditions 7 and 8 shown in Fig. 6, Coal A and Coal C were used respectively, and the sample amount was reduced from 200 g to 150 g. In Condition 9, a sample of Coal A was contained in a small container. The sample amount was reduced to 18 g. Other conditions were the same as those in Example 1. Note that "none" for refrigerated storage in Fig. 6 indicates that the test was carried out directly after the vacuum drying of the coal.

[0057] The results are shown in Fig. 11. Under Conditions 7 and 8, good results were obtained without irregular increases and decreases in temperature. The reason why the heat generation at low temperatures in Condition 8 was gentle is that the sample temperature at the start of the test was relatively high. Under Condition 9, compared with the test under Condition 7, it took several times longer for the sample to generate heat to the same temperature. From the above, it was confirmed that when the sample amount is too small, it is difficult to maintain the temperature required for the natural heat generation of the sample.

[0058] (Example 4) In Example 4, based on the results of the previous examples, vacuum drying was performed, sieving was carried out using a sieve with an aperture of 212 μm, and 150 g of the sample adjusted to a temperature of 30 °C was used. The oxygen flow rate was set at 70 mL / min. Under Conditions 10 to 13 shown in Fig. 6, in addition to Anthracite B, Anthracite C, and Anthracite A, another coal type (Anthracite D) which is considered to be less likely to generate natural heat was used.

[0059] The results are shown in Fig. 12. These results are equivalent to the results of the heat generation evaluation test (comparative example) carried out using the constant temperature bath shown in Fig. 13. From the above, it was confirmed that the heat generation property of coal can be correctly evaluated using the prototype machine created in Example 1.

[0060] (Example 5) In Example 5, an improved prototype machine having the same configuration as the evaluation apparatus 1 according to the embodiment was created. In the improved prototype machine, as shown in Fig. 14, it was improved to be small and portable. The heat insulation container is in the shape of a box that can be sealed, and the reaction container inside the heat insulation container has the same configuration as the small container of the previous prototype machine. An oxygen supply pipe, an exhaust pipe, and a thermocouple probe are attached to the lid of the reaction container. The reaction container is configured such that after removing the lid, the sample can be put into the reaction container and the lid can 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. Other conditions are the same as those in Example 4.

[0061] When comparing the test results using the improved tester with those using a thermostatic bath, it was found that the heat generation curves at a sample temperature of 40°C to 70°C were almost identical as shown in Figure 15. Also, when calculating and comparing the heating rates at a sample temperature of 40°C to 70°C, similar equivalent results were obtained. From the above, it was confirmed that in the heat generation property evaluation test of coal using the improved evaluation device, results equivalent to those of the heat generation property evaluation test of coal using a thermostatic bath can be obtained.

[0062] The above embodiments are illustrative, and the present invention is not limited thereto. 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. Also, inventions equivalent to the invention described in the claims are included in the present invention.

Description of Reference Numerals

[0063] 1 Evaluation device 2 Heat insulation container 3 Reaction container 4 Air supply pipe 42 Spiral pipe 5 Exhaust pipe 6 Heater 7,8 Thermometer 9 Control device

Claims

1. A heat-insulating container, A reaction container housed in the heat-insulating container for housing a sample, An air supply pipe connected to the reaction container through the heat-insulating container for supplying oxygen from an oxygen source into the reaction container, An exhaust pipe connected to the reaction container through the heat-insulating container for discharging the gas generated in the reaction container, A heater supported by 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 property evaluation device comprising the above.

2. A part of the air supply pipe is arranged so as to crawl on the surface of the reaction container, The heater heats the reaction container and the part of the air supply pipe arranged so as to crawl on the surface of the reaction container among the air supply pipe, The heat generation property evaluation device according to Claim 1.

3. A part of the air supply pipe is a spiral pipe spirally wound around the peripheral surface of the reaction container, The heater heats the peripheral surface of the reaction container and the spiral pipe, The heat generation property evaluation device according to Claim 2.

4. The oxygen source and the reaction container are connected to the spiral pipe so that oxygen flows from the lower side to the upper side of the reaction container, The heat generation property evaluation device according to Claim 3.

5. A first thermometer supported by the reaction container for measuring the temperature of the sample in the reaction container, A second thermometer supported by the air supply pipe for measuring the temperature of the oxygen flowing in the air supply pipe, A control device electrically connected to the heater, the first thermometer and the second thermometer for controlling the 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 property evaluation device according to any one of Claims 1 to 4.

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