JP7436816B2 - Oxidation property evaluation method, oxidation property evaluation system, and program - Google Patents

Description

The present invention relates to an oxidation property evaluation method, an oxidation property evaluation system, and a program, and is particularly suitable for use in evaluating the oxidation properties of coal.

Coal placed in an oxygen-containing atmosphere will self-heat through oxidation even if no external heat is applied, and in some cases it may ignite. Coal has different oxidation characteristics (natural calorific value due to oxidation) depending on the brand (information indicating the type of coal determined depending on the country of origin, etc.). Therefore, it is important to investigate the oxidation properties of various types of coal from the perspective of disaster prevention.

As a technique for deriving the oxidation characteristics of coal, Patent Document 1 discloses the following technique. First, an index related to exothermicity, the average reflectance of vitrinite measured by a microscope, and the amount of active ingredients or inactive ingredients measured by a microscope are measured, and the correlation therebetween is determined in advance by a statistical method. Then, by applying the measured values of the average vitrinite reflectance and the amount of active ingredients or inactive ingredients using a microscope of the coal sample whose oxidation properties are being investigated, to the correlation determined in advance, the exothermic properties of the coal sample are determined. Find indicators.

Patent Document 2 discloses that the CO ₂ concentration in the atmosphere of coal particles is measured in a region at a depth of 0.2 m or more from the surface of an open coal pile, and the oxidation and heat generation tendency of the coal is determined based on the measured CO ₂ concentration. This is disclosed.

Patent Document 3 discloses that a coal sample is oxidized in an atmosphere containing ¹⁷ O ₂ gas, a nuclear magnetic resonance spectroscopic analysis is performed on the oxidized coal sample, ^{a 17} O nuclear magnetic resonance spectrum is obtained, and a ¹⁷ O nuclear magnetic resonance spectrum is obtained. It is disclosed to evaluate the oxidation properties of a coal sample based on the area of peaks in a resonance spectroscopic spectrum.

Japanese Patent Application Publication No. 2003-215079 Japanese Patent Application Laid-Open No. 61-223640 Japanese Patent Application Publication No. 2019-164116

Clemens, A. H, Matheson, T. W, Fuel, 1996, 19, 787. M. S. Blois, Jr., H. W. Brown, and J. E. Mating, "Free Radicals in Biological Systems", Academic Press, New York, N.Y., 1961, p 130. M. Adams, M. S. Blois, and R. H. Sands, J. Chem. Phys., 28, 774 (1958). P. O'Neill, S. Steenken, and D. Schulte-Frohllnde, J. Phys. Chem., 79, 2173 (1975).

However, in the technique described in Patent Document 1, it is necessary to determine in advance the correlation between the exothermic index, the average reflectance of vitrinite measured by a microscope, and the amount of active ingredients or the amount of inactive ingredients measured by a microscope. Furthermore, when determining the exothermic index, it is necessary to heat the coal sample under vacuum. Furthermore, microscopic observation is required not only when determining correlations but also when determining an index regarding the exothermic nature of the coal sample whose oxidation properties are to be investigated.

With the technique described in Patent Document 2, CO ₂ concentration cannot be measured unless the coal is piled up in an open coal pile. Furthermore, a large amount of coal is required for measuring CO ₂ concentration.
In the technique described in Patent Document 3, a coal sample must be oxidized in an atmosphere containing ¹⁷ O ₂ gas.
As described above, the techniques described in Patent Documents 1 to 3 have a problem in that the workload for evaluating the oxidation characteristics of coal is large.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make it possible to easily evaluate the oxidation characteristics of coal.

The oxidation property evaluation method of the present invention includes a measurement step of measuring an electron spin resonance spectrum of a coal sample by an electron spin resonance method, and a g value and a spin concentration of the coal sample based on the electron spin resonance spectrum of the coal sample. Deriving a first spin concentration assumed as the spin concentration of oxygen radicals based on the g value and spin concentration of the coal sample derived by the first derivation step and the first derivation step. a second derivation step; and an evaluation step of evaluating the oxidation characteristics of the coal sample based on the first spin concentration derived by the second derivation step, the second derivation step Now, derive the first spin concentration by substituting the g value and spin concentration of the coal sample derived in the first derivation step into the first equation and the second equation. , the first equation is such that the spin concentration of the coal sample is determined by using the sum of a term including the first spin concentration and a term including a second spin concentration assumed as the spin concentration of carbon radicals. The second equation is an equation showing that the g value of the coal sample is the first g value assumed as the g value of the oxygen radical, and the g value of the carbon radical. This is an equation showing that the first g value is expressed as a weighted average value with respect to the second g value assumed as the value, and the weight for the first g value is the first spin concentration with respect to the spin concentration of the coal sample. It is a weight whose value is determined according to the ratio of concentrations, and the weight for the second g value is a weight whose value is determined according to the ratio of the second spin concentration to the spin concentration of the coal sample. shall be.

The oxidation property evaluation system of the present invention includes a measuring means for measuring an electron spin resonance spectrum of a coal sample by an electron spin resonance method, and a g value and spin concentration of the coal sample based on the electron spin resonance spectrum of the coal sample. Deriving a first spin concentration assumed as a spin concentration of oxygen radicals based on a first derivation means for deriving and the g value and spin concentration of the coal sample derived by the first derivation means. a second derivation means, the second derivation means calculates the g value and spin concentration of the coal sample derived by the first derivation means using a first equation and a second derivation means. The first spin concentration is derived by substituting into the equation, and the first equation is such that the spin concentration of the coal sample is a term containing the first spin concentration and the spin concentration of carbon radicals. This is an equation showing that the g value of the coal sample is expressed using the sum of the term including the second spin concentration assumed as This is an equation showing that the first g value assumed as a value and a second g value assumed as the g value of the carbon radical are expressed as a weighted average value, and the first g value The weight for the value is a weight whose value is determined according to the ratio of the first spin concentration to the spin concentration of the coal sample, and the weight for the second g value is a weight whose value is determined according to the ratio of the first spin concentration to the spin concentration of the coal sample. The second spin concentration is a weight whose value is determined according to the ratio of the spin concentrations of the second spin concentration, and the second spin concentration is used as an index for evaluating the oxidation characteristics of the coal sample.

The program of the present invention is for causing a computer to function as each means of the oxidation property evaluation system.

According to the present invention, it is possible to easily evaluate the oxidation characteristics of coal.

It is a figure showing an example of an electron spin resonance spectrum measured by electron spin resonance method. FIG. 1 is a diagram showing an example of the configuration of an oxidation property evaluation system. 3 is a flowchart illustrating an example of an oxidation property evaluation method. FIG. 3 is a diagram showing an example of the relationship between spin concentration and ¹⁷ O NMR spectrum area. FIG. 3 is a diagram showing an example of the relationship between the first spin concentration ratio and the ¹⁷ O NMR spectrum area.

<Knowledge>
Before describing the embodiments of the present invention, knowledge obtained by the present inventor will be described.
The present inventor focused on the fact that radicals are involved in the oxidation reaction of coal. As a measurement method for identifying radical species, there is an electron spin resonance (ESR) method.

FIG. 1 is a diagram showing an example of an electron spin resonance spectrum measured by an electron spin resonance method. In the following description, the electron spin resonance spectrum will be referred to as an ESR spectrum as necessary. Generally, in an electron spin resonance apparatus, a spectrum dP/dH obtained by first-order differentiation of a microwave absorption spectrum P with respect to a magnetic field H is measured as an ESR spectrum.
In the electron spin resonance method, g value, spin concentration, etc. are measured.
The g value is a value that reflects the environment around the unpaired electron (electron spin). The spin concentration has a value that reflects the number of unpaired electrons.

The g value is determined by the following equation (1).
g=hν/μ _β H ₀ ...(1)
Here, g is the g value. h is Planck's constant. ν is the resonant frequency. μ _β is a Bohr magneton. H ₀ is the resonant magnetic field.
Planck constant h and Bohr magneton μ _β are physical constants. The resonance frequency ν is the frequency of the microwave applied to the sample (the frequency of the microwave output from the microwave oscillator of the electron spin resonance apparatus). For example, the center frequency at the time of measurement is used as the resonance frequency ν. The resonant magnetic field (H ₀ ) is the value of the magnetic field H when the ESR spectrum dP/dH becomes 0. Note that the g value may be corrected using a marker such as an Mn marker.

From equation (1), the g value is inversely proportional to the resonant magnetic field (H ₀ ). The g value becomes larger as the resonant magnetic field (H ₀ ) becomes lower, and conversely, the g value becomes smaller as the resonant magnetic field (H ₀ ) becomes higher. When the resonant magnetic field (H ₀ ) has a similar value, the g value also has a similar value.
The spin concentration is proportional to the value obtained by second-order integration of the ESR spectrum dP/dH with the magnetic field H. Spin concentration is expressed as the number of spins per unit mass. Note that by simultaneously measuring the ESR spectrum of a sample whose spin concentration is known and the ESR spectrum of the sample to be measured, the spin concentration of the sample to be measured can be derived.
Since the electron spin resonance method itself can be realized using a known technique, detailed explanation thereof will be omitted here.

Since coal undergoes an oxidation reaction even at room temperature, if it is possible to measure the ESR spectrum of a coal sample at room temperature and derive the g value and spin concentration from the ESR spectrum, it is possible to determine the radical species of the radicals that contribute to the oxidation reaction. You can obtain information about the amount of radicals and the amount of radicals. However, there are aromatic hydrocarbon π radicals in coal that do not contribute to oxidation reactions. Therefore, multiple types of radicals exist in coal during the oxidation reaction process. Since the g values of these radicals are close to each other, the ESR spectrum of the coal sample becomes one spectrum as shown in FIG. 1. For this reason, in measurements by electron spin resonance, it is not possible to obtain ESR spectra separately for each of the π radicals of aromatic hydrocarbons and the radicals contributing to the oxidation reaction. From the above, there has been no method for evaluating the oxidation characteristics of coal from the ESR spectrum.

Therefore, the present inventor developed a method for deriving the radical amount (spin concentration) of π radicals of aromatic hydrocarbons and the radical amount (spin concentration) of radicals contributing to the oxidation reaction from a single ESR spectrum of a coal sample. It was investigated.
It is known that the g value of π radicals of aromatic hydrocarbons that do not contribute to oxidation reactions is 2.00250. The present inventors assumed that radical species other than π radicals of aromatic hydrocarbons in coal are one type of radical that contributes to the oxidation reaction, and based on the ESR spectrum of the coal sample, the aromatic hydrocarbon We have found that it is possible to derive the radical amount of radicals other than π radicals of hydrocarbons.

Under the assumption that radical species other than π radicals of aromatic hydrocarbons in coal are one type of radical that contributes to oxidation reactions, it is derived based on the results of second-order integration of the ESR spectrum of a coal sample. It is expressed by an equation that shows that the spin concentration of the aromatic hydrocarbon is the sum of the spin concentration of the π radical of the aromatic hydrocarbon and the spin concentration of the radical contributing to the oxidation reaction. Since there are two unknowns in this equation (the spin concentration of the π radical of the aromatic hydrocarbon and the spin concentration of the radical contributing to the oxidation reaction), another equation is required to derive the unknown. It becomes necessary.

Therefore, the present inventor assumed that the radicals contributing to the oxidation reaction (radicals other than π radicals of aromatic hydrocarbons) were radicals of quinones. This assumption was made because quinone radicals appear in the oxidation reaction mechanism proposed in Non-Patent Document 1. The g value of the radical of quinones is determined, for example, in the range of 2.00350 or more and 2.00469 or less, based on Non-Patent Documents 2 to 4.

Then, the present inventor found that the spin concentration of quinone radicals derived by simultaneously combining the above equation and the following equation has a correlation with the oxidation characteristics of the coal sample (for details, see Example (see FIG. 4(b)).

This equation states that the g value derived from the ESR spectrum of the coal sample based on equation (1) is the weighted average value of the g value of the π radical of aromatic hydrocarbons and the g value of the radical of quinones. This is an equation showing that Here, the weight for the g value of the π radical of the aromatic hydrocarbon is the ratio of the spin concentration of the π radical of the aromatic hydrocarbon to the spin concentration derived based on the result of second-order integration of the ESR spectrum of the coal sample. It is. Further, the weight for the g value of the quinone radical is the ratio of the spin concentration of the quinone radical to the spin concentration derived based on the result of second-order integration of the ESR spectrum of the coal sample.
The embodiments of the present invention described below are based on the above findings.

<Embodiment>
Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

<<Coal sample>>
A coal sample is obtained, for example, by adjusting the particle size of raw material coal. The coal used as the raw material for the coal sample is not particularly limited, and any of anthracite, bituminous coal, subbituminous coal, lignite, and peat can be used. Furthermore, if necessary, two or more of these types of coal may be mixed and used as a coal sample. Furthermore, the coal sample may be a processed product of coal.

Further, adhering moisture may be removed from the coal sample as necessary. Generally, coal used as a raw material has moisture attached to it depending on the type of coal and the environment in which it is stored. During the oxidation process, the energy generated by oxidation can not only be used to raise the temperature of the moisture, but also contribute to promoting the oxidation reaction. may affect the evaluation results. Therefore, when the purpose is to evaluate the oxidation properties of a coal sample while eliminating the influence of moisture, it is preferable to remove moisture from the coal sample.

The particle size of coal can be adjusted by, for example, pulverization or classification. The pulverization can be performed using various pulverizers such as a ball mill, bead mill, mortar, and hammer mill. Further, classification can be carried out using, for example, a classification sieve, a dry classifier such as a gravity classifier, an inertial classifier, or a centrifugal classifier.

For example, by heating the coal sample under a reduced pressure atmosphere, water present in the coal sample can be removed. The heating conditions can be, for example, under a reduced pressure atmosphere of 10 hPa or less, at 80° C. or more and 120° C. or less, and for 12 hours or more and 24 hours or less.

Note that it is not necessary to remove moisture from the coal sample. For example, it can be said that the oxidation characteristics of coal with moisture adhering to it depending on the storage environment more accurately indicate the oxidation characteristics of coal stored in that environment. Therefore, the oxidation properties of the obtained coal can be an important indicator when considering the storage method of coal in the relevant environment. The oxidation property evaluation method of this embodiment can be carried out without removing moisture present in the coal sample.

<<Oxidation property evaluation system/method>>
FIG. 2 is a diagram showing an example of the configuration of an oxidation property evaluation system. FIG. 3 is a flowchart illustrating an example of an oxidation property evaluation method.
In FIG. 2, the oxidation property evaluation system includes an ESR measurement device 210 and an oxidation property evaluation device 220.

The ESR measurement device 210 is a device that measures an ESR spectrum. The ESR measuring device 210 includes, for example, a cavity, an excitation power source, an electromagnet, a microwave oscillator, a detector, and a computer. A cavity resonator is placed between the electromagnets. When the electromagnet is excited by the excitation power source, a magnetic field is applied to the sample within the cavity resonator. A microwave oscillator irradiates the sample inside the cavity with microwaves. Change the strength of the magnetic field applied to the sample while it is irradiated with microwaves. At this time, a detector detects the energy absorbed by the microwave when the unpaired electrons in the sample resonate. The absorbed energy signal detected by the detector is processed, such as amplification, and then input into a computer. The computer then generates an ESR spectrum from the input signal.

The oxidation property evaluation device 220 is a device that receives the ESR spectrum signal measured by the ESR measurement device 210 and evaluates the oxidation property of the coal sample. The oxidation property evaluation device 220 has an acquisition section 221, a first derivation section 222, a second derivation section 223, and an evaluation section 224 as its functions. The hardware of the oxidation property evaluation device 220 is realized by using, for example, an information processing device having a CPU, ROM, RAM, HDD, and various interfaces. In FIG. 2, for convenience of notation and explanation, a case is illustrated in which the ESR measurement device 210 and the oxidation characteristic evaluation device 220 are different devices. However, at least some of the functionality of the oxidation property evaluation device 220 may be included in the computer of the ESR measurement device 210.

[Measurement and acquisition of ESR spectrum (S301)]
In this embodiment, the ESR measuring device 210 measures the ESR spectrum of a coal sample that is in the air and at room temperature. For example, a coal sample is placed in a quartz sample tube, and the quartz sample tube is inserted into a cavity. At this time, the inside of the quartz sample tube is communicated with the atmosphere, and the ESR spectrum of the coal sample in the atmosphere is measured. The ESR measuring device 210 can cool and heat the inside of the cavity resonator (sample), but in this embodiment, the inside of the cavity resonator (sample) is not cooled and heated, and the inside of the cavity resonator (sample) is not cooled or heated. The temperature of the sample) is set to be the same as the temperature around the ESR measuring device 210 (environmental temperature). As a result, the ESR spectrum of the coal sample at room temperature is measured.

The ESR measuring device 210 measures the ESR spectrum of the coal sample under the above conditions. The acquisition unit 221 acquires information on the ESR spectrum of the coal sample measured by the ESR measuring device 210. For example, when the ESR measurement device 210 and the oxidation property evaluation device 220 are communicably connected to each other via a communication line, the acquisition unit 221 receives information on the ESR spectrum of the coal sample transmitted from the ESR measurement device 210. can be received. Further, for example, when storing information on the ESR spectrum of a coal sample measured by the ESR measurement device 210 in a portable storage medium, the acquisition unit 221, after the storage medium is connected to the oxidation property evaluation device 220, Information on the ESR spectrum of the coal sample stored in the storage medium can be read out. Further, when the function of the acquisition unit 221 is included in the computer of the ESR measuring device 210, information on the ESR spectrum of the coal sample is acquired at the time the ESR spectrum of the coal sample is measured.

It is preferable to measure the ESR spectrum of a coal sample that is in the atmosphere and at room temperature as described above, since the ESR spectrum can be measured more easily. However, it is not necessarily necessary to measure the ESR spectrum of a coal sample that is in the air and at room temperature. For example, the ESR spectrum of the coal sample may be measured while the coal sample is heated to a predetermined temperature. Further, for example, the ESR spectrum of the coal sample may be measured with a high oxygen atmosphere inside the quartz sample tube. In this way, the ESR spectrum can be measured in a state where the oxidation of the coal sample is promoted.

[Derivation of g value and spin concentration from ESR spectrum (S302)]
The first derivation unit 222 derives the g value and spin concentration of the coal sample based on the ESR spectrum acquired by the acquisition unit 221. The first derivation unit 222 derives the g value of the coal sample from the resonant magnetic field (H ₀ ) of the ESR spectrum of the coal sample based on equation (1). Furthermore, the first derivation unit 222 derives the spin concentration of the coal sample based on the result of second-order integration of the ESR spectrum of the coal sample using the magnetic field H.
Note that the g value of the coal sample may be derived by manual calculation by an operator or calculation using a calculator. In this case, the operator may specify the resonant magnetic field (H ₀ ) by referring to the ESR spectrum, for example.

[Derivation of first spin concentration and second spin concentration (S303)]
The second derivation unit 223 calculates the spin concentration of oxygen radicals by substituting the g value and spin concentration of the coal sample derived by the first derivation unit 222 into the following equations (2) and (3). A first spin concentration assumed as the spin concentration of carbon radicals and a second spin concentration assumed as the spin concentration of carbon radicals are derived.

d1+d2=d0...(2)
d1×g1+d2×g2=g0×d0...(3)

Here, d1 is a first spin concentration assumed as the spin concentration of oxygen radicals. In this embodiment, a case will be exemplified in which the spin concentration of quinone radicals is used as the first spin concentration (d1) assumed as the spin concentration of oxygen radicals. d0 is the spin concentration of the coal sample derived by the first derivation unit 222.
d2 is a second spin concentration assumed as the spin concentration of carbon radicals. In this embodiment, a case will be exemplified in which the spin concentration of π radicals of aromatic hydrocarbons is used as the second spin concentration (d2) assumed as the spin concentration of carbon radicals.

g1 is the first g value assumed as the g value of oxygen radicals. In this embodiment, a case will be exemplified in which the g value of a quinone radical (=2.00469 ) is used as the first g value (g1) assumed as the g value of an oxygen radical.
g2 is the second g value assumed as the g value of the carbon radical. In this embodiment, a case will be exemplified in which the g value (=2.00250) of the π radical of an aromatic hydrocarbon is used as the second g value (g2) assumed as the g value of the carbon radical.

In this way, the first g value (g1) assumed as the g value of oxygen radicals and the second g value (g2) assumed as the g value of carbon radicals are calculated using equations (2) and (3). ) is set in advance and becomes a constant in equations (2) and (3).
g0 is the g value of the coal sample derived by the first derivation unit 222.
In addition, when using the g value of a quinone radical as the first g value (g1) assumed as the g value of oxygen radicals, as described above, the first g value assumed as the g value of oxygen radicals The value (g1) can be selected from a range of 2.00350 or more and 2.00469 or less.

In equations (2) and (3), the unknowns are the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d2) assumed as the spin concentration of carbon radicals. There are two. Therefore, from equations (2) and (3), the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d2) assumed as the spin concentration of carbon radicals are derived. be done. However, the second spin concentration (d2) assumed as the spin concentration of carbon radicals does not need to be derived.

Note that equation (3) can be rewritten as equation (3') below.
(d1/d0)×g1+(d2/d0)×g2=g0...(3')
As shown in equation (3'), the g value (g0) of the coal sample is calculated by setting the weighting coefficient for the first g value (g1) to d1/d0 and the weighting coefficient for the second g value (g2) to d2. /d0, and is expressed as a weighted average value of the first g value (g1) and the second g value.
The first spin concentration (d1) assumed to be the spin concentration of oxygen radicals and the second spin concentration (d2) assumed to be the spin concentration of carbon radicals are derived by hand calculation by an operator or using a calculator. It may also be performed by calculation.

[Evaluation of oxidation properties (S304)]
The evaluation unit 224 evaluates the oxidation characteristics of the coal sample based on the first spin concentration (d1) derived by the second derivation unit 223.
As mentioned above, in this embodiment, it is assumed that radical species other than π radicals of aromatic hydrocarbons in coal are one type of radical contributing to the oxidation reaction, and one type of radical contributing to the oxidation reaction is a radical of quinones. Therefore, the value of the first spin (d1) assumed as the spin concentration of oxygen radicals itself does not match the spin concentration of radicals contributing to the oxidation reaction in the coal sample.

However, the larger the first spin concentration (d1) assumed as the spin concentration of oxygen radicals, the easier it is to oxidize and the larger the amount of self-heating. For this reason, for example, by comparing the first spin concentration (d1) assumed as the oxygen radical spin concentration of each of multiple coal samples of different brands, it is possible to compare the first spin concentration (d1) of each coal sample with respect to other coal samples. It is possible to evaluate the relative quality of oxidation properties. In this case, the evaluation unit 224 determines that, for example, the larger the absolute value of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals, the larger the self-heating amount; It is assumed that the smaller the absolute value of the first spin concentration (d1) assumed as the concentration, the smaller the self-heating amount, and it is possible to rank coal samples of multiple brands in terms of the magnitude of the self-heating amount. .

The method for evaluating the oxidation properties of a coal sample is not limited to this method. For example, the oxidation properties of a coal sample may be evaluated as follows.
First, we derive the first spin concentration (d1), which is assumed to be the spin concentration of oxygen radicals, for the brand of coal that self-heats and ignites among the coals stored in the open or in containers at the operation site. I'll keep it. In addition, we derived the first spin concentration (d1), which is assumed to be the spin concentration of oxygen radicals, for brands of coal that do not generate self-heating among the coal that is stored in the open or in containers at the operation site. put.

Then, based on the first spin concentration (d1) assumed as the spin concentration of these oxygen radicals, a threshold value for the first spin concentration (d1) assumed as the spin concentration of oxygen radicals may be determined. .
In this case, the evaluation unit 224 determines that when the first spin concentration (d1) assumed as the spin concentration of oxygen radicals for the coal sample is larger than the threshold value, the coal sample is easily oxidized and It is evaluated that the natural calorific value is large.
Furthermore, the evaluation unit 224 may derive the absolute value of the difference between the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and a threshold value for the coal sample. This difference is a value that reflects the possibility of ignition due to spontaneous heat generation of the coal sample.

Furthermore, the evaluation unit 224 does not need to evaluate the oxidation characteristics of the coal sample from the first spin concentration (d1) itself, which is assumed as the spin concentration of oxygen radicals. For example, the evaluation unit 224 evaluates the oxidation of the coal sample based on the ratio (=d1÷d0) of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals to the spin concentration (d0) of the coal sample. Preferably, the properties are evaluated (see Examples (Figure 5) for details). In this case, as described above, even if the oxidation characteristics of each coal sample are evaluated relative to other coal samples, the oxidation characteristics are evaluated by comparing them with a threshold value. It's okay.

The evaluation unit 224 can output information indicating the results of the evaluation performed as described above. The form of output can be, for example, at least one of displaying on a computer display, transmitting to an external device, and storing in a storage medium external to or internal to the oxidation property evaluation device 220.
Note that the evaluation itself by the evaluation unit 224 may be performed by an operator. In this case, the oxidation property evaluation device 220 outputs information indicating the first spin concentration (d1) assumed as the spin concentration of oxygen radicals for the coal sample derived by the second derivation unit 223. do.

<<Summary>>
As described above, in this embodiment, the oxidation property evaluation device 220 calculates the g value (g0) and spin concentration (d0) based on the ESR spectrum of the coal sample using the first equation (spin concentration (d0) of the coal sample). is the sum of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d2) assumed as the spin concentration of carbon radicals) , the second equation (where the g-value (g0) of the coal sample is the first g-value (g1) assumed as the g-value of oxygen radicals and the second g-value (g1) assumed as the g-value of carbon radicals) The first spin concentration (d1) assumed as the g value of oxygen radicals is derived by substituting it into the equation (which shows that it is a weighted average value with g2). Therefore, by measuring ESR spectra and simple calculations, it is possible to derive an index for evaluating the oxidation characteristics of a coal sample. Therefore, the oxidation characteristics of coal can be easily evaluated.

Furthermore, in this embodiment, the ESR spectrum of a coal sample in the atmospheric atmosphere is measured. Therefore, an index for evaluating the oxidation characteristics of a coal sample can be derived without placing the coal sample in a special atmosphere. Therefore, it is possible to evaluate the oxidation characteristics of coal even more easily.
Furthermore, in this embodiment, the ESR spectrum of a coal sample at room temperature is measured. Therefore, an index for evaluating the oxidation properties of a coal sample can be derived without heating the coal sample. Therefore, it is possible to evaluate the oxidation characteristics of coal even more easily.

<<Variation example>>
[Modification 1]
In this embodiment, the first g value (g1) assumed as the g value of oxygen radicals is the g value of quinone radicals (2.00350 or more and 2.00469 or less), and the g value of carbon radicals is A case is illustrated in which the assumed second g value (g2) is the g value (=2.00250) of the π radical of aromatic hydrocarbon. In this way, the first spin concentration (d1) assumed as the spin concentration of oxygen radicals can be derived using a g value that is considered appropriate based on the mechanism of the oxidation reaction in the coal sample.

However, as described above, in this embodiment, it is assumed that radical species other than π radicals of aromatic hydrocarbons in coal are one type of radical that contributes to the oxidation reaction. Therefore, the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d1) assumed as the spin concentration of carbon radicals are derived from equations (2) and (3). The value of d2) does not necessarily correspond to the actual spin concentration value in the coal sample.

Therefore, the absolute amount of spontaneous heat generation due to oxidation cannot be estimated from the value of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals. However, for example, the oxidation characteristics of a coal sample can also be evaluated by comparing the relative magnitude of the natural calorific value due to oxidation for each of a plurality of brands of coal samples. Therefore, as described in this embodiment, for example, by comparing the first spin concentration (d1) assumed as the spin concentration of oxygen radicals for coal samples of multiple brands, the oxidation characteristics of the coal sample can be determined. can be evaluated.

As described above, the values of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d2) assumed as the spin concentration of carbon radicals are the actual spin concentration in the coal sample. It is possible to evaluate the oxidation properties of a coal sample without having to deal with it.
Therefore, the values of the first g value (g1) assumed as the g value of oxygen radicals and the second g value (g2) assumed as the g value of carbon radicals are not particularly limited.
For example, assuming that one type of radical contributing to the oxidation reaction is a radical other than quinones, the first g value (g 1 ) assumed as the g value of oxygen radical is The g value may be adopted.

The g value (g0) of the coal sample is larger than the second g value (g2) assumed as the g value of carbon radicals of the coal sample, and the first g value assumed as the g value of oxygen radicals. If the range is smaller than (g1) (g1<g0<g2), the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration assumed as the spin concentration of carbon radicals. The spin concentrations (d2) of 2 are both positive values. Therefore, by doing this, there is no need to take the absolute value of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals.

However, it is not necessary that the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d2) assumed as the spin concentration of carbon radicals both have positive values. . For example, the g value (g0) of the coal sample is larger than the second g value (g2) assumed as the g value of carbon radicals in the coal sample, and the first g value assumed as the g value of oxygen radicals It does not have to be within a range smaller than the g value (g1) (it does not have to be g2<g0<g1). In this way, the first spin concentration (d1) assumed as the spin concentration of oxygen radicals becomes a negative value. In this way, when the first spin concentration (d1) assumed as the spin concentration of oxygen radicals is a negative value, the larger the absolute value of the first spin concentration (d1), the easier it is to oxidize and the spontaneous heat generation. It is evaluated that the quantity is large.

Further, the sign of the first g value (g1) assumed as the g value of oxygen radicals of the coal sample and the second g value (g2) assumed as the g value of carbon radicals does not matter.
However, it is preferable that the positive and negative signs of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals in each coal sample of each brand are the same. In other words, if the first spin concentration (d1) assumed as the spin concentration of oxygen radicals in each of the coal samples of a certain brand is a positive value, the oxygen radicals in each of the coal samples of other brands are The first spin concentration (d1) assumed as the spin concentration is also a positive value. Similarly, if the first spin concentration (d1) assumed as the spin concentration of oxygen radicals is a negative value, the first spin concentration (d1) assumed as the spin concentration of oxygen radicals in each of the other brands of coal samples is The spin concentration (d1) is also set to a negative value. In this way, the magnitude (absolute value) of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals can be directly compared.

However, if the first g value (g1) assumed as the g value of oxygen radicals of the coal sample and the second g value (g2) assumed as the g value of carbon radicals are positive values, and The respective g values (g1 , g2) is preferable because it is suitable for the physical meaning of the g value and spin concentration.

Note that the g value (g0) of the coal sample is the first g value (g1) assumed as the g value of oxygen radicals of the coal sample, or the second g value (g2) assumed as the g value of carbon radicals of the coal sample. , the first spin concentration (d1) assumed as the spin concentration of oxygen radicals or the second spin concentration (d2) assumed as the spin concentration of carbon radicals becomes zero. Therefore, the g value (g0) of the coal sample is the first g value (g1) assumed as the g value of oxygen radicals of the coal sample, and the second g value (g2) assumed as the g value of carbon radicals of the coal sample. The first g value (g1) assumed as the g value of oxygen radicals of the coal sample and the second g value (g2) assumed as the g value of carbon radicals of the coal sample are determined so that they are different values. preferable.

As described above, the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration (d2) assumed as the spin concentration of carbon radicals are likely values as spin concentrations. You don't have to. The same holds true for the first g value (g1) assumed as the g value of oxygen radicals and the second g value (g2) assumed as the g value of carbon radicals. These names were given based on the assumption that the radical species in the coal during the oxidation reaction are carbon radicals and one type of radical contributing to the oxidation reaction.

[Modification 2]
As explained in Modification 1, the first g value (g1) assumed as the g value of oxygen radicals and the second g value (g2) assumed as the g value of carbon radicals are determined by, for example, ESR measurement. It is also possible to determine g values that cannot be obtained from the ESR spectrum measured by device 210. However, if you do this, the resonant magnetic field (H ₀ ) corresponding to the first g value (g1) assumed as the g value of oxygen radicals and the second g value (g1) assumed as the g value of carbon radicals. The resonant magnetic field (H ₀ ) corresponding to g2) is significantly different from the resonant magnetic field (H ₀ ) corresponding to the g value (g0) of the coal sample. In general, the ESR measuring device 210 has high measurement sensitivity on the high magnetic field side, so the higher the resonant magnetic field (H ₀ ) is, the higher the spin concentration becomes. Therefore, in such a case, in equations (2) and (3), the first spin concentration (d1) assumed as the spin concentration of oxygen radicals and the second spin concentration assumed as the spin concentration of carbon radicals. It is preferable to correct (d2).

For example, in place of equation (2), the spin concentration (d0) of the coal sample is the first spin concentration (d1) assumed as the spin concentration of oxygen radicals, and the second spin concentration (d1) assumed as the spin concentration of carbon radicals. An equation is used that shows that it is a weighted average value with the spin concentration (d2) of .

In this equation, the weight for the first spin concentration (d1) assumed as the spin concentration of oxygen radicals is the first g value assumed as the g value of oxygen radicals with respect to the resonant magnetic field (H ₀ ) of the coal sample. It is the ratio of the resonant magnetic field (H ₀ ) corresponding to the value (g1). Here, the resonant magnetic field (H ₀ ) corresponding to the first g value (g1) assumed as the g value of oxygen radicals is the microwave frequency ν obtained when measuring the ESR spectrum of the coal sample and the oxygen It is derived by substituting the first g value (g1) assumed as the g value of the radical into equation (1).

In addition, in this equation, the weight for the second spin concentration (d2) assumed as the spin concentration of carbon radicals is the weight for the second spin concentration (d2) assumed as the g value of carbon radicals with respect to the resonant magnetic field (H ₀ ) of the coal sample. It is a weight whose value is determined according to the ratio of the resonant magnetic field (H ₀ ) corresponding to the g value (g2) of . Here, the resonant magnetic field (H ₀ ) corresponding to the second g value (g2) assumed as the g value of carbon radicals is the microwave frequency ν obtained when measuring the ESR spectrum of the coal sample and the carbon It is derived by substituting the second g value (g2) assumed as the g value of the radical into equation (1).

In addition, in equation (3), the weight for the first g value (g1) assumed as the g value of oxygen radicals is the weight for the first g value (g1) assumed as the spin concentration of oxygen radicals with respect to the spin concentration (d0) of the coal sample. and the resonant magnetic field ( _{H 0} ).
Similarly, the weight for the second g value (g2) assumed as the g value of carbon radicals is set to the second spin concentration (d2) assumed as the spin concentration of carbon radicals with respect to the spin concentration (d0) of the coal sample. ) and the ratio of the resonant magnetic field (H ₀ ) corresponding to the second g value (g2) assumed as the g value of carbon radicals to the resonant magnetic field (H ₀ ) obtained from the ESR spectrum of the coal sample. Let it be the product of

Specifically, the following equation (4) is used in place of equation (2), and the following equation (5) is used in place of equation (3).
H1×d1+H2×d2=H0×d0...(4)
d1×H1×g1+d2×H2×g2=g0×H0×d0...(5)
Here, H1 is a resonant magnetic field (H ₀ ) corresponding to a first g value (g1) assumed as the g value of oxygen radicals. H2 is a resonant magnetic field (H ₀ ) corresponding to a second g value (g2) assumed as the g value of carbon radicals. H0 is the resonant magnetic field (H ₀ ) obtained from the ESR spectrum of the coal sample.

In equation (4), the weighting factor for the first spin concentration (d1) assumed as the spin concentration of oxygen radicals is H1/H0, and the weighting factor for the second spin concentration (d2) assumed as the spin concentration of carbon radicals is H1/H0. The weighting coefficient for is H2/H0. In equation (5), the weighting factor for the first g value (g1) assumed as the g value of oxygen radicals is (d1/d0)×(H1/H0), and the weighting factor for the first g value (g1) assumed as the g value of carbon radicals is (d1/d0)×(H1/H0). The weighting coefficient for the g value (g2) of 2 is (d2/d0)×(H2/H0).

As described above, the weight for the first g value (g1) assumed as the g value of oxygen radicals is the first spin concentration assumed as the spin concentration of oxygen radicals with respect to the spin concentration (d0) of the coal sample. As long as it is a value determined according to the ratio of (d1), it is not limited to the ratio itself. Similarly, the weight for the second g value (g2) assumed as the g value of carbon radicals is the second spin concentration (d2) assumed as the spin concentration of carbon radicals with respect to the spin concentration (d0) of the coal sample. ) is not limited to the ratio itself, as long as it is a value determined according to the ratio.

In addition, from the viewpoint of reducing the influence of the measurement sensitivity of the ESR measurement device 210 as described above, the first g value (g1) assumed as the g value of oxygen radicals is 2.0010 or more and 2.1000 or less. The second g value (g2) assumed as the g value of the carbon radical is preferably within the range of 2.0010 or more and 2.0300 or less.

[Other variations]
Note that the embodiments of the present invention described above can be realized by a computer executing a program. Furthermore, a computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM, etc. can be used.
Furthermore, the embodiments of the present invention described above are merely examples of implementation of the present invention, and the technical scope of the present invention should not be construed as limited by these. It is something. That is, the present invention can be implemented in various forms without departing from its technical idea or its main features.

<Example>
Next, an example will be described.
In this example, coal samples A to E were prepared for each of coals A to E having mutually different oxidation properties.
Then, the ESR spectra of each of the coal samples A to E were measured in the air at room temperature. As the ESR measurement device, an electron spin resonance device (model name: JES-FA200) manufactured by JEOL Ltd. was used. The g values and spin concentrations of coal samples A to E were derived from the ESR spectra of coal samples A to E. The results are shown in Table 1. In this example, the unit of spin concentration is spin/g (number of spins per gram).

Then, using the g value (g0) and spin concentration (d0) of coal samples A to E shown in Table 1, the oxygen radical A first spin concentration (d1) assumed as the spin concentration and a second spin concentration (d2) assumed as the spin concentration of carbon radicals were derived. Here, the first g value (g 1 ) assumed as the g value of oxygen radicals was set as the g value of quinone radicals (=2.0046 9) . Furthermore, the second g value (g2) assumed as the g value of carbon radicals was set as the g value of π radicals of aromatic hydrocarbons (=2.00250). Table 2 shows the results.

Patent Document 3 states that the larger the area of the peak in the ¹⁷ O nuclear magnetic resonance spectrum, the higher the spontaneous heating property of coal (the larger the amount of natural heat generated by oxidation), and the smaller the area of the peak in the ¹⁷ O nuclear magnetic resonance spectrum. It has been shown that coal has a lower spontaneous heating property (lower natural calorific value due to oxidation). Therefore, the area of the peak in the ¹⁷ O nuclear magnetic resonance spectrum can be used as an index for evaluating the oxidation properties of coal. In addition, in Patent Document 3, as an index for examining the validity of this (an index indicating spontaneous heat generation), a coal sample measured using a spontaneous ignition test device SIT-2 (Shimadzu Corporation) is used. The time required for the temperature to reach 200°C is used.

Therefore, in this example, the areas of the peaks of the ¹⁷ O nuclear magnetic resonance spectra of coal samples A to E were derived using the method described in Patent Document 3. In the following description, a ¹⁷ O nuclear magnetic resonance spectrum will be referred to as a ¹⁷ O NMR spectrum as necessary.

As described in Patent Document 3, coal samples A to E were oxidized in an atmosphere containing ¹⁷ O ₂ gas, and the oxidized coal samples A to E were subjected to nuclear magnetic resonance (NMR) spectroscopy. Analysis was performed and a ¹⁷ O NMR spectrum was obtained. The peak areas of the ¹⁷ O NMR spectra for the obtained coal samples A to E were derived. Note that the coal sample used for measuring the ESR spectrum was not subjected to the oxidation treatment that was applied to the coal sample used for measuring ^{the 17} O NMR spectrum.

Then, the correlation between the spin concentration obtained from the ESR spectrum and the area of the peak of the ¹⁷ O nuclear magnetic resonance spectrum was investigated.
FIG. 4 is a diagram showing an example of the relationship between spin concentration and ¹⁷ O NMR spectrum area.
^{The 17} O NMR spectrum area is the area of the peak of the ¹⁷ O NMR spectrum obtained as described in Patent Document 3.

FIG. 4(a) is a diagram showing an example of the relationship between the total spin concentration and the ¹⁷ O NMR spectrum area. The total spin concentration is the spin concentration (d0) of coal samples A to E, and is the value of the spin concentration (d0) shown in Table 1. FIG. 4(b) is a diagram showing an example of the relationship between the first spin (d1) assumed as the spin concentration of oxygen radicals and ^{the 17} O NMR spectrum area. The second spin (d1) assumed as the spin concentration of oxygen radicals is the value of the first spin concentration (d1) shown in Table 2.

As shown in FIG. 4(a), there is no correlation between the total spin concentration (spin concentration (d0) of the coal sample) and ^{the 17} O NMR spectrum area (R ² =0.2372). On the other hand, as shown in FIG. 4(b), there is a good positive correlation between the first spin (d1) assumed as the spin concentration of oxygen radicals and ^{the 17} O NMR spectrum area (R ² = 0 .7558).

From the above, the larger the (absolute value) of the first spin (d1) assumed as the spin concentration of oxygen radicals, the higher the spontaneous heating property of the coal sample; The smaller the magnitude (absolute value) of the first spin (d1) assumed to be, the lower the spontaneous heat generation of the coal sample can be evaluated. For example, in the example shown in Table 2, it can be evaluated that coal sample B has the highest spontaneous heating property, and coal sample E has the lowest spontaneous heating property.

Note that the first spin (d1) assumed as the spin concentration of oxygen radicals is derived from equations (2) and (3). Therefore, if the first g value (g1) assumed as the g value of oxygen radicals and the second g value (g2) assumed as the g value of carbon radicals are determined as described above, then the oxygen The correlation between the first spin concentration (d2) assumed as the spin concentration of radicals and ^{the 17} O NMR spectrum area is the first g value (g1) assumed as the g value of oxygen radicals and the g value of carbon radicals. The correlation is good regardless of the second g value (g2) assumed as .

FIG. 5 is a diagram showing an example of the relationship between the first spin concentration ratio and the ¹⁷ O NMR spectrum area. The ratio of the first spin concentration is the ratio (=d1÷d0) of the first spin concentration (d1) assumed as the spin concentration of oxygen radicals to the total spin concentration (d0). As shown in FIG. 5, the correlation between the ratio of the first spin (d1) assumed as the spin concentration of oxygen radicals to the total spin concentration (d0) and ^{the 17} O NMR spectrum area (R ² = 0.9204 ) is higher than the correlation (R ² =0.7558) between the first spin (d1) assumed as the spin concentration of oxygen radicals and ^{the 17} O NMR spectrum area shown in FIG. 4(b). Therefore, it can be seen that it is preferable to evaluate the oxidation characteristics of the coal sample based on the ratio of the first spin concentration assumed as the spin concentration of oxygen radicals to the total spin concentration (d0).

210: ESR measurement device, 220: Oxidation property evaluation device, 221: Acquisition section, 222: First derivation section, 223: Second derivation section, 224: Evaluation section

Claims (16)

a measurement step of measuring an electron spin resonance spectrum of a coal sample by an electron spin resonance method;
A first derivation step of deriving the g value and spin concentration of the coal sample based on the electron spin resonance spectrum of the coal sample;
a second derivation step of deriving a first spin concentration assumed as the spin concentration of oxygen radicals based on the g value and spin concentration of the coal sample derived in the first derivation step;
an evaluation step of evaluating the oxidation characteristics of the coal sample based on the first spin concentration derived by the second derivation step,
In the second derivation step, by substituting the g value and spin concentration of the coal sample derived in the first derivation step into the first equation and the second equation, the first derivation step is performed. Derive the spin concentration of
In the first equation, the spin concentration of the coal sample is determined by using the sum of a term including the first spin concentration and a term including the second spin concentration assumed as the spin concentration of carbon radicals. is an equation showing that
The second equation is such that the g value of the coal sample is between a first g value assumed as the g value of the oxygen radical and a second g value assumed as the g value of the carbon radical. is an equation showing that it is expressed as a weighted average value,
The weight for the first g value is a weight whose value is determined according to the ratio of the first spin concentration to the spin concentration of the coal sample,
A method for evaluating oxidation characteristics, wherein the weight for the second g value is a weight whose value is determined according to a ratio of the second spin concentration to the spin concentration of the coal sample. The first equation is an equation indicating that the spin concentration of the coal sample is the sum of the first spin concentration and the second spin concentration,
The weight for the first g value is the ratio of the first spin concentration to the spin concentration of the coal sample,
The oxidation property evaluation method according to claim 1, wherein the weight for the second g value is a ratio of the second spin concentration to the spin concentration of the coal sample. The oxidation property evaluation method according to claim 1 or 2, wherein the first g value is 2.00350 or more and 2.00469 or less. According to any one of claims 1 to 3, in the evaluation step, the oxidation characteristics of the coal sample are evaluated based on the ratio of the first spin concentration to the spin concentration of the coal sample. Method for evaluating the oxidation properties of In the evaluation step, based on the first spin concentration derived in the second derivation step for a plurality of mutually different types of coal samples, a relative value of at least two oxidation properties of the plurality of types of coal samples is determined. The oxidation property evaluation method according to any one of claims 1 to 4, characterized in that the quality is evaluated. In the first derivation step, the g value and spin concentration of the coal sample are derived based on an electron spin resonance spectrum of the coal sample obtained by an electron spin resonance method at room temperature. 5. The oxidation property evaluation method according to any one of Item 5. Claim 1, wherein in the first derivation step, the g value and spin concentration of the coal sample are derived based on an electron spin resonance spectrum of the coal sample obtained by an electron spin resonance method in the atmosphere. The method for evaluating oxidation properties according to any one of items 6 to 6. A measuring means for measuring an electron spin resonance spectrum of a coal sample by an electron spin resonance method;
a first derivation means for deriving the g value and spin concentration of the coal sample based on the electron spin resonance spectrum of the coal sample;
a second deriving means for deriving a first spin concentration assumed as a spin concentration of oxygen radicals based on the g value and spin concentration of the coal sample derived by the first deriving means; death,
The second deriving means substitutes the g value and spin concentration of the coal sample derived by the first deriving means into the first equation and the second equation, thereby obtaining the first result. Derive the spin concentration of
In the first equation, the spin concentration of the coal sample is determined by using the sum of a term including the first spin concentration and a term including the second spin concentration assumed as the spin concentration of carbon radicals. is an equation showing that
The second equation is such that the g value of the coal sample is between a first g value assumed as the g value of the oxygen radical and a second g value assumed as the g value of the carbon radical. is an equation showing that it is expressed as a weighted average value,
The weight for the first g value is a weight whose value is determined according to the ratio of the first spin concentration to the spin concentration of the coal sample,
The weight for the second g value is a weight whose value is determined according to the ratio of the second spin concentration to the spin concentration of the coal sample,
An oxidation characteristic evaluation system, wherein the second spin concentration is used as an index for evaluating the oxidation characteristics of the coal sample. The first equation is an equation indicating that the spin concentration of the coal sample is the sum of the first spin concentration and the second spin concentration,
The weight for the first g value is the ratio of the first spin concentration to the spin concentration of the coal sample,
The oxidation property evaluation system according to claim 8, wherein the weight for the second g value is a ratio of the second spin concentration to the spin concentration of the coal sample. The oxidation property evaluation system according to claim 8 or 9, wherein the first g value is 2.00350 or more and 2.00469 or less. 11. The method according to claim 8, further comprising evaluation means for evaluating the oxidation characteristics of the coal sample based on the first spin concentration derived by the second derivation means. Oxidation characterization system described. The oxidation characteristic evaluation system according to claim 11, wherein the evaluation means evaluates the oxidation characteristics of the coal sample based on a ratio of the first spin concentration to the spin concentration of the coal sample. The evaluation means calculates a relative value of at least two oxidation properties of the plurality of different types of coal samples based on the first spin concentration derived by the second derivation means for the plurality of mutually different types of coal samples. The oxidation property evaluation system according to claim 11, characterized in that it evaluates quality. 9. The first deriving means derives the g value and spin concentration of the coal sample based on an electron spin resonance spectrum of the coal sample obtained by an electron spin resonance method at room temperature. 14. The oxidation property evaluation system according to any one of Item 13. 9. The first derivation means derives the g value and spin concentration of the coal sample based on an electron spin resonance spectrum of the coal sample obtained by an electron spin resonance method in the atmosphere. The oxidation property evaluation system according to any one of items 1 to 14. A program for causing a computer to function as each means of the oxidation property evaluation system according to any one of claims 8 to 15.

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