JP6972863B2 - Spontaneous combustion of coal evaluation device and evaluation method - Google Patents

Description

The present invention relates to an apparatus and an evaluation method for evaluating the spontaneous combustion property of coal.

Coal stored in coal silos and the like reacts with oxygen and water in the air to generate heat, which may lead to ignition, which is a major cause of fire accidents.
In recent years, not only high-grade coal but also low-grade coal has been used more and more due to problems with the supply of high-grade coal and improvements in thermal power generation technology. There is a problem that it is expensive. Further, since the characteristics of spontaneous combustion differ not only for coal types but also for lots, there is a craving for a method for evaluating the spontaneous combustion property of coal in advance.

Conventionally, as a method for evaluating the natural heat generation property of such coal in advance, a sample container equipped with a vent and a sample temperature measuring means is immersed in a heating tank, and an oxygen-containing gas is passed through the sample in the sample container. It is a method of measuring the heat of oxidation reaction of a sample, and has a double structure in which an inner container equipped with a sample storage part made of a film having airtightness in the main part in contact with the sample is housed in an outer container via an air layer. While using a sample container, a method has been proposed in which the heat of the oxidation reaction of the sample is measured while keeping the temperature in the heating tank for storing the sample container following the temperature of the sample in the sample storage section (patented). See Document 1).

Further, at present, a method for evaluating the spontaneous combustion property of coal called the R70 method is adopted overseas (see Non-Patent Document 1). In this method, oxygen is aerated at a constant flow rate in about 200 g of coal in an adiabatic oven, the temperature rise time for spontaneous combustion from 40 ° C to 70 ° C is measured, and the spontaneous heat generation of coal is measured based on the temperature rise time. Is a way to evaluate.

Further, a method (spontaneous combustion test (SIT)) of evaluating the spontaneous heat generation of coal from the temperature rise time from 110 ° C. to 180 ° C. using several g of coal is also used (see Non-Patent Document 2). ).

Japanese Unexamined Patent Publication No. 58-150847

B. Beamish et al. Adiabatic testing procedures for determining the self-heating propensity of coal and sample aging effects, Thermochimica Acta 362 (2000) 79-87. http://www.mcet.co.jp/service/analysis/material/img/pyrophoric_test.pdf

The above-mentioned Patent Document 1 aims to measure with a small amount of sample, but the small amount is about 370 g (Example of Patent Document 1), and it cannot be said that the sample is sufficiently reduced. That is, although the sample container of the apparatus used in the method of Patent Document 1 is trying to secure heat retention by adopting a two-layer structure, the heat retention of the inner container is not sufficient and a coal sample of about 370 g is not used. Therefore, it is not possible to realize a temperature rise due to spontaneous combustion of the coal sample at a low temperature. Further, since a liquid is used for the heating tank, it is a large-scale device and is not practical.

Further, even in the R70 method of Non-Patent Document 1, there is a problem that the amount of coal sample required for evaluation (measurement) is as large as about 200 g, and pretreatment such as crushing and drying takes time. In addition, there is a problem that the evaluation (measurement) itself takes time. Therefore, it takes a lot of labor to continuously evaluate various coal samples in the field, and improvement thereof is required.

Further, in the spontaneous combustion test (SIT) of Non-Patent Document 2, although there is an advantage that the amount of coal sample used is very small, the amount of coal sample is too small and the evaluation (measurement) is at a high temperature of 110 ° C. or higher. Since it is carried out, the influence of water contained in coal cannot be evaluated, and it cannot always be said to be an accurate evaluation. Also, it is necessary to use a very expensive device.

An object of the present invention is to provide an apparatus and a method capable of evaluating the spontaneous combustion property of coal from a low temperature in a short time by using a small amount of coal sample.

Among the methods currently used, the present inventors attempted to improve the R70 method in view of the fact that the effect of water contained in coal cannot be evaluated in the pyrophoricity test (SIT). First, various studies were conducted to improve the biggest drawback of the R70 method, which is that the amount of coal sample required for measurement is large, but if the amount of coal sample is reduced, the natural temperature rise does not occur, and evaluation should be performed. Faced with the problem of not being able to.

In order to solve this problem, the present inventors have conducted various studies focusing on reducing the heat removal amount among the calorific value and heat removal amount related to the natural temperature rise of the coal sample. As a result, the coal sample is stored in a small inner container with a small heat capacity, and the upper part of the inner container is opened and stored in a heat-retaining outer container such as a thermos bottle, so that a small amount of sample is obtained. However, it was found that the temperature of the coal sample naturally rises at a low temperature of about 40 ° C., and the present invention has been completed. Specifically, by using a small inner container with a thin wall thickness (a container with a small heat capacity) made of a material having a small specific heat, and further accommodating the inner container in a communication state in a heat-retaining outer container. The heating gas introduced into the inner container also fills the outer container to ensure sufficient heat retention of the inner container, and even at a low temperature of about 40 ° C, a small amount of coal sample is heated by natural heat generation. Was found to occur.

That is, the present invention is as follows.
[1] A sample container including an inner container for accommodating a crushed coal sample and an outer container for accommodating the inner container, a sample temperature measuring means for measuring the temperature of the crushed coal sample in the inner container of the sample container, and the above. A heating tank that houses the sample container and adjusts the temperature inside the tank according to the temperature of the crushed coal sample, and oxygen whose temperature is adjusted according to the temperature of the crushed coal sample in the inner container of the sample container. A device for evaluating the natural heat generation of coal equipped with an oxygen supply means for supplying the contained gas. The inner container of the sample container has a smaller heat capacity than the outer container, and the upper part of the inner container is used. A coal natural heat generation evaluation device characterized in that the sample is housed in an outer container in an open state.
[2] The coal spontaneous combustion evaluation device according to [1], wherein the heat medium in the heating tank is a gas.
[3] The coal spontaneous combustion evaluation device according to [1] or [2], wherein the heat capacity of the inner container is 0.5 to 10.0 J / K.
[4] The coal spontaneous combustion evaluation device according to any one of [1] to [3], wherein the inner container is made of an aluminum material.
[5] The coal spontaneous combustion evaluation device according to any one of [1] to [4], wherein the capacity of the inner container is ^{30 to 120 cm 3.}
[6] The coal spontaneous combustion evaluation device according to any one of [1] to [5], wherein the outer container is a thermos bottle.
[7] The coal spontaneous combustion evaluation device according to [6], wherein the thermos bottle is a commercially available product.

[8] A method for evaluating the natural heat generation of coal using the coal natural heat generation evaluation device according to any one of the above [1] to [7], wherein 20 to 80 g of crushed coal sample is contained in an inner container. , A method for evaluating spontaneous heat generation of coal, which comprises measuring a time for raising a temperature from a predetermined initial temperature to a predetermined final temperature and evaluating the spontaneous heat generation of coal from the measurement time.
[9] The coal spontaneous combustion evaluation method according to [8], wherein the predetermined initial temperature is in the range of 20 ° C to 50 ° C, and the predetermined final temperature is in the range of 60 to 150 ° C.
[10] The method for evaluating spontaneous coal heat generation according to [8] or [9], wherein a coal crushed sample that has not been sieved after crushing is used.
[11] The method for evaluating spontaneous coal heat generation according to any one of [8] to [10], wherein a crushed coal sample having a water content of more than 0% and 50% or less is used.
[12] Any of [8] to [11], wherein the repetition accuracy of the heating rate value from 40 ° C. to 70 ° C. using a crushed coal sample having a water content of 0% is ± 10%. The described method for evaluating spontaneous heat generation of coal.

According to the coal spontaneous combustion evaluation device and the coal spontaneous combustion evaluation method of the present invention, it is possible to evaluate the spontaneous combustion of coal from a low temperature in a short time by using a small amount of coal sample.

It is a figure which compared the particle size distribution in the case of crushing and sieving coal, and the particle size distribution in the case of only crushing coal. It is a schematic whole view of the coal spontaneous combustion property evaluation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the sample container of the coal spontaneous heat generation evaluation apparatus which concerns on one Embodiment of this invention. It is a comparative figure of the temperature rise time from 40 degreeC to 70 degreeC between the evaluation method of this invention and the R70 method.

The natural heat generating property of coal of the present invention measures the temperature of a sample container including an inner container for accommodating a coal crushed sample and an outer container for accommodating the inner container, and the temperature of the coal crushed sample in the inner container of the sample container. The sample temperature measuring means, the heating tank that houses the sample container and adjusts the temperature inside the tank according to the temperature of the coal crushed sample, and the inner container of the sample container follow the temperature of the coal crushed sample. It is equipped with an oxygen supply means for supplying oxygen-containing gas whose temperature is adjusted, and the inner container of the sample container has a smaller heat capacity than the outer container, and the upper part of the inner container is open to the outer container. It is characterized by being contained.

In the apparatus of the present invention, since the coal crushed sample is housed in a container having a smaller heat capacity than the outer container, the amount of heat removed from the coal crushed sample is small, and the coal crushed sample is effectively kept warm. Even at low temperatures, it is possible to promote the natural heat generation of a small amount of crushed coal sample. In particular, in the apparatus of the present invention, since the upper part of the inner container is in an open state and is housed in the outer container in a state of communicating with the inside of the outer container, the heated oxygen-containing gas introduced into the inner container is outside. The inside of the container is also filled to keep the inner container sufficiently warm, and sufficient heat is retained in the coal sample. For example, in the apparatus of Patent Document 1, since the inner container and the outer container of the sample container are not communicated with each other and are separated, the heating gas introduced into the inner container is discharged to the outside as it is. In the apparatus of the present invention, the heating gas is filled between the inner container and the outer container (around the inner container) to ensure sufficient heat retention of the inner container.

This makes it possible to raise the temperature of a small amount of crushed coal sample of about 20 to 100 g by spontaneous combustion even at a low temperature of about 40 ° C. Therefore, for example, as in the currently used R70 method, it is possible to measure the temperature rise time due to spontaneous combustion from 40 ° C. to 70 ° C. and evaluate the spontaneous heat generation of coal based on the temperature rise time. It becomes.

Further, in the apparatus of the present invention, since the heat retention property in the sample container is high, it is not necessary to use a heating tank containing a liquid as a heat medium as in the apparatus of Patent Document 1, and the apparatus is heated by a normal gas. It is also possible to use a heating tank that is heated. Further, without using a special container as the sample container, for example, a commercially available thermos bottle is used as the outer container, and the inner container is made of an aluminum material, so that the device can be configured extremely simply.

Hereinafter, the coal spontaneous combustion evaluation device of the present invention will be described in detail.
First, a sample container, which is a feature of the present invention, will be described.
The sample container in the coal natural heat generation evaluation device of the present invention includes an inner container and an outer container, and the crushed coal sample is housed in the inner container.

The outer container is a container that can have a closed structure having heat retention, and examples thereof include a thermos made of glass, stainless steel, etc. (a container in which the space between the inner layer and the outer layer is a vacuum). be able to. This outer container may be a custom-made product dedicated to the apparatus of the present invention, but a commercially available thermos bottle (off-the-shelf product) such as a water bottle or a pot can be used. As a result, the apparatus of the present invention can be constructed at low cost, and for example, a plurality of outer containers can be prepared in advance, or replacement can be easily performed when the outer container is damaged.

The inner container contains a crushed sample of coal to be evaluated, and has a smaller heat capacity than the outer container. The heat capacity of the inner container is preferably 0.5 to 10.0 J / K, more preferably 0.8 to 6.0 J / K, and more preferably 1.0 to 5.0 J / K. Is even more preferable. The material of the inner container is preferably a material having a small specific heat and easy processing, and examples thereof include aluminum, iron, and stainless steel. Among these, aluminum is preferable because it is easily deformed and a container having a thin wall thickness (a container having a small heat capacity) can be easily manufactured.

As the capacity of the inner container, since the contained coal crushed sample is about 20 to 80 g, preferably about 30 to 60 g, and more preferably about 35 to 45 g, the size is set according to the capacity of the coal crushed sample. Is preferable. Specifically, as the capacity of the inner container is preferably 30～120Cm ^3, more preferably 45～90Cm ^3, further preferably 50 to 70 cm ^3.

In the apparatus of the present invention, the inner container is housed in the outer container with its upper portion open. That is, the inner container is housed in the outer container in a state of communicating with the outer container.

Here, the oxygen supply means in the apparatus of the present invention will be described. The oxygen supply means uses coal in an inner container of an oxygen-containing gas whose temperature is adjusted according to the temperature of the crushed coal sample measured by the sample temperature measuring means. It is a means to supply the crushed sample and promotes the natural heat generation of the crushed coal sample. The oxygen supply means includes, for example, an oxygen-containing gas tank and a gas supply pipe for supplying gas from the oxygen-containing gas tank, and the gas supply pipe is introduced into an inner container via an outer container and has a tip thereof. A gas discharge port is arranged at the lower end of the crushed coal sample to supply a heated oxygen-containing gas to the crushed coal sample.

The gas released from this gas outlet diffuses upward over the entire crushed coal sample and is discharged from the gas discharge pipe to the outside of the outer container. At this time, as described above, the inner container is the same. Since the upper part is housed in the outer container in an open state, the heated gas is discharged to the outside of the outer container via the inside of the outer container. Therefore, the heating gas is also filled in the outer container, which makes it possible to improve the heat retention in the inner container.

Further, the sample temperature measuring means in the apparatus of the present invention is a means for measuring the temperature of the coal crushed sample in the sample container, which is inserted into the inner container, and measures an appropriate place of the coal crushed sample. It may be present, or it may be measured at a plurality of points.

Further, the heating tank in the apparatus of the present invention accommodates the sample container (inner container and outer container) and adjusts the temperature in the tank according to the temperature of the crushed coal sample to keep the sample container warm. The heat medium in the heating tank of the present invention may be a liquid, but is preferably a gas. For example, by arranging a gas supply pipe having a predetermined length in this heating tank, the oxygen-containing gas is heated to a temperature similar to that of the crushed coal sample while passing through the gas supply pipe. Therefore, the oxygen-containing gas heated in this heating tank may be supplied to the coal pulverized sample without using a device for separately heating the oxygen-containing gas.

Subsequently, the method for evaluating the spontaneous combustion of coal of the present invention will be described.
In the coal natural exothermic evaluation method of the present invention, the time for accommodating 20 to 80 g of crushed coal sample in an inner container and raising the temperature from a predetermined initial temperature to a predetermined final temperature by using the above-mentioned coal spontaneous exothermic evaluation device of the present invention. It is characterized in that the natural heat generation property of coal is evaluated from the measurement time. For example, the predetermined initial temperature is in the range of 20 ° C to 50 ° C, and the predetermined final temperature is in the range of 60 to 150 ° C. Similar to the currently used R70 method, it is particularly preferable that the predetermined initial temperature is 40 ° C. and the predetermined final temperature is 70 ° C.

The particle size of the crushed coal sample used in the method for evaluating the spontaneous combustion of coal of the present invention is preferably 90% or more, preferably substantially 100% of the sample, preferably 500 μm or less, and more preferably 300 μm or less. It is preferably 250 μm or less, and more preferably 250 μm or less. After crushing, the crushed coal sample used in the method of the present invention may be sieved so that the size is smaller than a predetermined size, but this sieving may be omitted. Conventionally, the sieving process has become an indispensable process, and this sieving process has taken a very long time (about 4 hours). Especially in the case of coal, sieving is difficult unless it is half-thirsty, and it takes time to semi-dry before sieving (about 2 hours). However, the present inventors have found that when pulverized to a size of about 300 μm or less, there is almost no difference in particle size distribution between those that have been sieved and those that have not been sieved, and the same evaluation can be performed even if the sieve is omitted. Found (see Figure 1). Moreover, the literature (HAIHUI WANG, BOGDAN Z. DLUGOGORSKI, ERIC M. KENNEDY: COAL OXIDATION AT LOW TEMPERATURE: OXYGEN CONSUMPTION, OXIDATION PRODUCTS, REACTION MECHANISM AND KINETIC MODELLING, PROGRESS IN ENERGY AND COMBUSTION SCIENCE 29 (2003) According to this, it is known that there is no difference in the reaction rate below several hundred μm (Fig. 3).

That is, conventionally, coal is crushed (2-3 minutes), semi-dried (about 2 hours), sieved (for example, <212 μm) (about 4 hours), and finally vacuum dried (70 ° C.). Although the dried coal crushed sample was prepared after 3 days), in the present invention, semi-drying and sieving can be omitted, so that the time can be shortened by about 6 hours.

Further, in the coal natural heat generation evaluation method of the present invention, it is possible to evaluate a dried coal crushed sample having a water content of substantially 0%, and even a coal crushed sample containing water can be measured. It is possible to do. For example, it is possible to use a crushed coal sample having a water content of more than 0% and 50% or less, and it is preferable to use a crushed coal sample having a water content of more than 0% and 20% or less. Therefore, depending on the state of the crushed coal sample, the vacuum drying step may be omitted.

Further, in the method for evaluating the spontaneous combustion of coal of the present invention, it is preferable that the repetition accuracy of the temperature rising rate value from 40 ° C. to 70 ° C. using a crushed coal sample having a water content of 0% is in the range of ± 10%. , ± 8% is more preferable. The repeatability of the present invention refers to the fluctuation range when measured 5 times under the same conditions.

Subsequently, an example of the coal spontaneous heat generation evaluation device of the present invention will be described with reference to the drawings. FIG. 2 is a schematic overall view of the coal spontaneous heat generation evaluation device according to the embodiment of the present invention, and FIG. 3 is a diagram showing a sample container of the coal natural heat generation evaluation device according to the embodiment of the present invention. be.

As shown in FIG. 2, the coal spontaneous combustion evaluation device 10 according to the embodiment of the present invention includes a heating tank 11 and a sample container (reaction container) 12 housed in the heating tank 11. .. Further, the coal natural heat generation evaluation device 10 controls the temperature of the oxygen-containing gas by collecting the temperature data of the oxygen-containing gas (oxidizing gas) supplied to the sample container 12 and the coal crushed sample. In addition, a control device 14 for controlling the flow rate of oxygen gas is provided. In the heating tank 11, the internal temperature is controlled based on the temperature data of the coal crushed sample C. Further, reference numeral 15 indicates a nitrogen gas tank for storing nitrogen gas.

Subsequently, the sample container 12 will be described in detail. As shown in FIG. 3, the sample container 12 includes an inner container 16 containing the crushed coal sample C and an outer container 17 containing the inner container 16. The inner container 16 is housed in the outer container 17 with its upper portion open. The outer container 17 is sealed by the sealing lid 18, supported by the support base 19, and arranged in the heating tank 11.

Further, a gas supply pipe 20 for supplying oxygen-containing gas from the oxygen gas tank 13 penetrates the sealing lid 18, and its tip (gas discharge port) is arranged at the lower end of the inner container 16. As a result, the oxygen-containing gas is supplied to the coal crushed sample C. On the other hand, a gas discharge pipe 21 for discharging the supplied oxygen-containing gas to the outside is provided so as to penetrate the sealing lid 18. Further, the sample temperature measuring device 22 is introduced into the inner container 16 through the sealing lid 18.

In the coal natural heat generation evaluation device 10 of the present invention, first, nitrogen gas having a predetermined initial temperature (for example, 40 ° C.) is first transferred from the nitrogen gas tank 15 to the coal crushed sample C in the inner container 16 via the gas supply pipe 20. It is supplied and the coal crushed sample C is stabilized at a predetermined initial temperature.

Subsequently, when the nitrogen gas is switched to oxygen gas and oxygen gas is supplied to the coal crushed sample C, the coal crushed sample C begins to generate heat naturally. The oxygen gas introduced into the coal crushed sample C diffuses upward to the entire coal crushed sample C and is discharged to the outside from the gas discharge pipe 21 provided so as to penetrate the closed lid 18 of the outer container 17. At this time, the heating oxygen gas is also filled in the outer container 17, the heat retention property in the inner container 16 is enhanced, and the natural temperature rise of the coal crushed sample C can be promoted even at a low temperature. It should be noted that the heat retention in the inner container 16 is enhanced by the same action during the initial supply of nitrogen gas.

When the temperature of the coal crushed sample C rises due to the spontaneous heat generation of the coal crushed sample C, the heated oxygen gas is supplied in accordance with this, and the temperature in the heating tank 11 is also raised in accordance with this. This operation is continued, the temperature of the coal crushed sample C is raised to a predetermined final temperature, and the spontaneous heat generation of the coal is evaluated by the time required for the rise from the predetermined initial temperature to the predetermined final temperature. In other words, it is evaluated that the longer the time required for the rise, the less likely it is that spontaneous combustion will occur.

The spontaneous combustion property of coal was evaluated using the devices shown in FIGS. 2 and 3. A commercially available stainless steel thermos [commercially available water bottle body] (outer diameter: 60 mm, inner diameter: 40 mm, height: 130 mm) is used as the outer container, and a container made of aluminum (inner diameter: 25 mm, height: 130 mm) is used as the inner container. : 125 mm) was used. The weight of aluminum was 1.5 g. Therefore, the heat capacity of the inner container is 0.88 (specific heat of aluminum) x 1.5 g = 1.32 J / K.

[Example 1]
The evaluation method of the present invention and the R70 method actually used at present were compared with the temperature rise time from 40 ° C to 70 ° C.
Sub-bituminous coal dry coal was used as the coal crushed sample. In the evaluation method of the present invention, 40 g of a crushed coal sample (maximum particle size of less than 212 μm) was used, and in the R70 method, 210 g of a crushed coal sample (maximum particle size of less than 212 μm) was used. The amount of oxygen gas supplied was set to 20 ml / min in the evaluation method of the present invention and 50 ml / min in the R70 method.

The results are shown in FIG. In the evaluation method of the present invention, the temperature rising time from 40 ° C. to 70 ° C. was shortened by about 20% as compared with the R70 method.

[Example 2]
The repeatability of the evaluation method of the present invention was evaluated. The evaluation method of the present invention was repeated 5 times under the same conditions (same conditions as in Example 1), and the fluctuation of the temperature rising rate value from 40 ° C. to 70 ° C. was calculated. As the coal crushed sample, subbituminous coal dry coal was used, and the supply amount of oxygen gas was set to 20 ml / min. As a result, the temperature rise rate value was 5.7 ± 6% ° C./h, and the accuracy of the temperature rise rate value was ± 6%. Therefore, it was clarified that the repeatability was high.

The spontaneous combustion evaluation device and evaluation method for coal of the present invention are industrially useful because they can quickly evaluate the spontaneous combustion property of coal on site.

10 Coal natural heat generation evaluation device 11 Heating tank 12 Sample container 13 Oxygen gas tank 14 Control device 15 Nitrogen gas tank 16 Inner container 17 Outer container 18 Sealed lid 19 Support stand 20 Gas supply pipe 21 Gas discharge pipe 22 Sample temperature measuring device

Claims (12)

A sample container including an inner container for accommodating a crushed coal sample and an outer container for accommodating the inner container, and a sample container.
A sample temperature measuring means for measuring the temperature of the crushed coal sample in the inner container of the sample container,
A heating tank that houses the sample container and adjusts the temperature inside the tank according to the temperature of the crushed coal sample.
An oxygen supply means for supplying an oxygen-containing gas whose temperature is adjusted according to the temperature of the crushed coal sample to the inner container of the sample container.
It is a device for evaluating the spontaneous combustion of coal equipped with
The inner container of the sample container has a smaller heat capacity than the outer container, and the upper part of the inner container is housed in the outer container in an open state, and the gas supply pipe of the oxygen supply means is inside the inner container. A coal natural heat generation evaluation device characterized by being introduced. A sample container including an inner container for accommodating a crushed coal sample and an outer container consisting of a thermos bottle for accommodating the inner container, and a sample container.
A sample temperature measuring means for measuring the temperature of the crushed coal sample in the inner container of the sample container,
A heating tank that houses the sample container and adjusts the temperature inside the tank according to the temperature of the crushed coal sample.
An oxygen supply means for supplying an oxygen-containing gas whose temperature is adjusted according to the temperature of the crushed coal sample to the inner container of the sample container.
It is a device for evaluating the spontaneous combustion of coal equipped with
A coal spontaneous combustion evaluation device characterized in that the inner container of the sample container has a smaller heat capacity than the outer container, and the upper portion of the inner container is housed in the outer container in an open state. Coal self-heating evaluation apparatus according to claim 1, wherein the outer container is a thermos. The coal spontaneous combustion evaluation device according to any one of claims 1 to 3, wherein the heat medium in the heating tank is a gas. The coal spontaneous combustion evaluation device according to any one of claims 1 to 4, wherein the heat capacity of the inner container is 0.5 to 10.0 J / K. The coal spontaneous combustion evaluation device according to any one of claims 1 to 5 , wherein the inner container is made of an aluminum material. The coal spontaneous combustion evaluation device according to any one of claims 1 to 6 , wherein the capacity of the inner container is ^{30 to 120 cm 3.} A method for evaluating the spontaneous combustion of coal using the coal spontaneous combustion evaluation device according to any one of claims 1 to 7.
A coal crushed sample of 20 to 80 g is stored in an inner container, the time for raising the temperature from a predetermined initial temperature to a predetermined final temperature is measured, and the natural heat generation of coal is evaluated from the measured time. Gender evaluation method. The coal spontaneous combustion evaluation method according to claim 8, wherein the predetermined initial temperature is in the range of 20 ° C to 50 ° C, and the predetermined final temperature is in the range of 60 to 150 ° C. The method for evaluating spontaneous coal heat generation according to claim 8 or 9, wherein a crushed coal sample that has not been sieved after crushing is used. The method for evaluating spontaneous coal heat generation according to any one of claims 8 to 10, wherein a crushed coal sample having a water content of more than 0% and 50% or less is used. The spontaneous coal heat generation according to any one of claims 8 to 11, wherein the repetition accuracy of the temperature rising rate value from 40 ° C. to 70 ° C. using a crushed coal sample having a water content of 0% is ± 10%. Gender evaluation method.

Images