Method for suppressing spontaneous heat generation in solid carbon resources, and solid carbon resource storing method using same

Abstract

This method for suppressing spontaneous heat generation in solid carbon resources comprises a step for adding, as a spontaneous heat generation suppressing agent, a petroleum-based additive to a solid carbon resource.

Description

Method for inhibiting spontaneous heat generation of solid carbon resources and method for storing solid carbon resources using the same

[0001] The present invention relates to a method for suppressing spontaneous heat generation of a solid carbon resource and a method for storing a solid carbon resource using the same. This application claims priority based on Japanese Patent Application No. 2023-2772, filed on January 12, 2023, the contents of which are incorporated herein by reference.

[0002] Solid carbon resources such as coal and biomass charcoal, which is expected to see increased use in the future, are sometimes stored in large piles in yards, etc. Here, solid carbon resources generate heat spontaneously, so their temperature must be carefully controlled.

[0003] Several techniques have been proposed to suppress spontaneous heating of such solid carbon resources. For example, Patent Document 1 discloses a method of suppressing spontaneous heating by using a temperature rise / spontaneous combustion inhibitor containing at least one substance selected from a radical scavenger and an oxygen scavenger to reduce the amount of radicals generated by the reaction between carbonaceous powder and oxygen, and also describes that the inhibitor may contain a nonionic surfactant.

[0004] Furthermore, Patent Document 2 discloses a method for producing modified coal in which spontaneous combustion is suppressed by drying coal in an atmosphere containing a radical scavenger made of an organic compound having a hydroxyl group, such as alcohol or phenol.

[0005] Furthermore, Patent Document 3 discloses a stabilization method in which coal is heat-treated at a temperature of 100 to 350°C until the moisture content of the coal becomes substantially 0% by weight, and then subjected to an oxidation treatment, thereby simultaneously dehydrating the coal and preventing spontaneous combustion.

[0006] Japanese Patent Publication No. 2001-164254 Japanese Patent Publication No. 2011-201947 Japanese Patent Publication No. 59-074189

[0007] However, the method described in Patent Document 1 requires the use of a large amount of a specific compound, which poses a cost problem. For example, adding a significant amount of a nonionic surfactant as a heat suppressant to carbonaceous powder, which is used in large amounts industrially, is likely to further increase production costs. Furthermore, even in the method described in Patent Document 2, adding a significant amount of an organic compound having a hydroxyl group is difficult from a cost perspective.

[0008] In Patent Document 3, heat generation is suppressed by deliberately subjecting coal to an oxidation treatment after dehydration, but the effect of the oxidation treatment when dehydration is not required is unclear.

[0009] As described above, conventional methods are required to be further improved in terms of cost and process simplicity.

[0010] The present invention has been made in consideration of the above problems, and its object is to provide an inexpensive and simple method for suppressing spontaneous heat generation of solid carbon resources and a method for storing solid carbon resources using the same.

[0011] (1) A method for suppressing spontaneous heat generation of a solid carbon resource, comprising the step of adding a petroleum-based additive to a solid carbon resource as a spontaneous heat generation inhibitor. (2) A method for suppressing spontaneous heat generation of a solid carbon resource according to (1), in which the petroleum-based additive is added to the solid carbon resource in an amount of 1% by mass or more. (3) A method for suppressing spontaneous heat generation of a solid carbon resource according to (1) or (2), further comprising the step of heat-treating the solid carbon resource to which the petroleum-based additive has been added in an inert gas atmosphere at a temperature of 20°C or higher for 1 hour or more. (4) A method for storing a solid carbon resource, in which a solid carbon resource treated by the method according to any one of (1) to (3) is stored.

[0012] According to the present invention, by including a step of adding a petroleum-based additive to a solid carbon resource, the spontaneous heat generation of the solid carbon resource can be reduced easily and at low cost.

[0013] 1 is a graph showing the corrected temperature rise curves of Test Nos. 1 to 4 (Comparative Example 1, Inventive Examples 1 to 3). This is a graph comparing the T200 delay time values ​​calculated from the corrected temperature rise curves of Test Nos. 1 to 4 (Comparative Example 1, Inventive Examples 1 to 3). This is a graph showing the corrected temperature rise curves of Test No. 4 (Inventive Example 3) of Example 1 and Test Nos. 5 to 8 (Inventive Examples 4 to 7) of Example 2. This is a graph comparing the T200 delay time values ​​calculated from the corrected temperature rise curves of Test No. 4 (Inventive Example 3) of Example 1 and Test Nos. 5 to 7 (Inventive Examples 4 to 6) of Example 2.

[0014] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result of repeated testing focusing on petroleum-based additives, have arrived at the present invention.

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In this specification, solid carbon resources are not particularly limited as long as they are solid materials primarily composed of carbon. For example, they include carbonaceous materials used as raw materials for coke production, fuels, and heating agents in power generation and converters. Examples of carbonaceous materials include fossil resources (such as anthracite, bituminous coal, subbituminous coal, lignite, and peat) and organic resources derived from living organisms (such as biomass itself and biomass charcoal (carbonized or semi-carbonized biomass such as charcoal and black pellets) produced by thermally treating biomass). In this specification, petroleum heavy oil refers to crude oil with high viscosity and specific gravity and heavy components obtained by refining petroleum. Petroleum tar refers to a viscous, black to brown oily substance produced by thermal decomposition of petroleum or petroleum-derived substances. Petroleum pitch refers to the residue obtained after refining crude oil to produce petroleum or diesel fuel, or the residue obtained by vacuum distillation of petroleum. Furthermore, petroleum heavy oil is liquid at room temperature (20°C), while petroleum tar and petroleum pitch are solid at room temperature (20°C). The petroleum additive is composed of at least one of petroleum heavy oil, petroleum tar, and petroleum pitch. The petroleum additive is an additive derived from petroleum, and is a petroleum additive. The petroleum additive is preferably composed of at least one of petroleum tar and petroleum pitch, more preferably composed of at least one of petroleum heavy oil and petroleum pitch, and even more preferably composed of petroleum pitch.

[0016] The present invention relates to a method for suppressing spontaneous heat generation of a solid carbon resource, which includes a step of adding a petroleum-based additive to a solid carbon resource, and a method for storing a solid carbon resource treated using this method. Petroleum-based additives have traditionally been used industrially as coal binders when coal is used as a raw material for coke production. Specifically, they are used as binders that exhibit caking properties at high temperatures (350°C to 550°C) to complement the caking properties of low-expansion coal (such as non-caking coal). However, the present inventors have newly discovered that petroleum-based additives, when added to or mixed with a solid carbon resource, have the effect of suppressing spontaneous heat generation of the solid carbon resource. That is, in the present invention, a petroleum-based additive is used as an additive for suppressing spontaneous heat generation (spontaneous heat generation inhibitor).

[0017] The flow of the coke production process in the ironmaking process in the steel industry, for example, involves a ship stacking process, a coal storage process (such as a yard), a coal blending process, a crushing process, a molding process, and a coke oven charging process, in this order, and the petroleum-based additive as a binder is added to coal that has been blended with a predetermined amount of raw coal in the coal blending process after the coal blending process (see, for example, JP 2014-70125 and JP 2008-120973).In contrast, when a petroleum-based additive is used as a spontaneous heat generation inhibitor in the ironmaking process in the steel industry, as in the present invention, it is preferably added at any stage between the ship stacking process and the coal blending process (including the carrying-in process and the transport process between the above processes from the ship stacking process to the coal blending process). More preferably, the petroleum-based additive is added at one or both of the following stages: after the ship-stacking process and before the coal storage process (e.g., the stage from when coal (coking coal) is unloaded from a ship to when it is transported to a coal storage location such as a yard) and after the coal storage process and before the coal blending process (e.g., the stage from when coal is transported from the coal storage location to the coal blending location). When using a petroleum-based additive as a spontaneous combustion inhibitor, its effect can be achieved by adding it at any stage before the coke oven charging process. However, adding it upstream in the process flow can suppress the possibility of spontaneous combustion downstream. When using a petroleum-based additive as a spontaneous combustion inhibitor for coal in processes other than the ironmaking process in the steel industry (e.g., the coal-fired power generation process), it is added at a stage before the process in which coal is used as fuel. For example, the additive may be added at least at any stage of after the ship-stacking process and before the coal storage process, during coal storage at the yard, during the process of transporting coal from the yard to a coal storage bin, during storage in a coal storage bin, or during the coal blending process, and upstream addition is preferred. More specifically, the spontaneous heat generation inhibitor may be mixed with coal before storage in a yard or coal layer, and then stored, or the spontaneous heat generation inhibitor may be added to coal during storage (in storage).

[0018] The spontaneous heat generation of solid carbon resources is due to the wide variety of highly reactive radicals abundantly contained in solid carbon resources, which drive oxidation reactions. Petroleum-based additives (at least one of petroleum heavy oil, petroleum pitch, and petroleum tar) contain many structures with hydrogen-donating properties, such as naphthenic rings. It is believed that this hydrogen-donating property exerts some kind of chemical interaction on the solid carbon resource (trapping radicals), promoting the oxidation-inhibiting reaction of the solid carbon resource and thereby suppressing the spontaneous heat generation of the solid carbon resource. It was known that aromatic compounds with hydrogen-donating naphthenic rings promote the thermoplasticity of coal, but their effect of suppressing the spontaneous heat generation of solid carbon resources was unknown. An example of an embodiment of the present invention is described in detail below.

[0019] First Embodiment In this embodiment, a heat generation suppression treatment of a solid carbon resource is performed by adding a petroleum-based additive. Here, it is preferable to pre-treat the solid carbon resource prior to the addition treatment of the petroleum-based additive. It is also preferable to pre-treat the petroleum-based additive prior to adding it to the solid carbon resource. Furthermore, it is preferable to perform a mixing step and a storage step after the addition treatment of the petroleum-based additive. That is, in the first embodiment, it is preferable to first perform the pre-treatment step of the solid carbon resource and the pre-treatment step of the petroleum-based additive, then the petroleum-based additive addition step, then the mixing step, and then the storage step. From the perspective of suppressing spontaneous heat generation of the solid carbon resource, it is sufficient to perform at least the petroleum-based additive addition step, and if storage is also performed, it is preferable to perform the storage step subsequently. However, in order to maximize the effects of this embodiment, it is preferable to perform each of the above-mentioned steps.

[0020] (Pretreatment process of solid carbon resources, pretreatment process of petroleum-based additives) Pretreatment of solid carbon resources is, for example, a particle size adjustment process of the solid carbon resources that serve as raw materials. Pretreatment of petroleum-based additives is, for example, a particle size adjustment process of the petroleum-based additives that serve as raw materials. Pretreatment of petroleum-based additives is performed as needed. For example, it can be performed when the petroleum-based additive is solid. The particle size adjustment of the solid carbon resources and petroleum-based additives can be performed, for example, by pulverization or classification. Pulverization can be performed using various pulverizers such as a ball mill, bead mill, mortar, hammer mill, etc. Furthermore, classification can be performed, for example, using a dry classifier such as a classification sieve, gravity classifier, inertia classifier, or centrifugal classifier.

[0021] In this step, in order to advance the oxidation inhibition reaction in a short time, it is preferable to make the particle size of the petroleum-based additive relatively small to promote the oxidation inhibition reaction. Specifically, the petroleum-based additive preferably has a particle size of less than 5 mm, and more preferably a particle size of less than 2 mm. Furthermore, when mixing with the solid carbon resource, if the petroleum-based additive is too fine, it will not mix well, so it is preferable that the petroleum-based additive has a particle size of 1 mm or more. The particle size is specified using a sieve. Particles that pass through a sieve with a mesh size of X mm are defined as having a particle size of less than X mm, and particles that do not pass through a sieve with a mesh size of X mm are defined as having a particle size of X mm or more.

[0022] Pre-treatment of the solid carbon resource is carried out as necessary. For example, in the mixing step described below, when a petroleum-based additive is sprayed onto the solid carbon resource, pre-treatment of the solid carbon resource is not necessarily required. When mixing using a container, mixer, or the like, the solid carbon resource is pre-treated in order to mix the solid carbon resource and the petroleum-based additive more uniformly, and the average particle size of the solid carbon resource is preferably 0.5 to 1.5 times the average particle size of the petroleum-based additive, and more preferably approximately the same as the average particle size of the petroleum-based additive (0.8 to 1.2 times). That is, the average particle size of the solid carbon resource is preferably 0.5 to 1.5 times the average particle size of the petroleum-based additive, and more preferably 0.8 to 1.2 times. Furthermore, the average particle size of the solid carbon resource is preferably 1.5 to 1.2 times the average particle size of the petroleum-based additive, and more preferably 1.2 to 1.5 times the average particle size of the petroleum-based additive. Here, the average particle size is the arithmetic mean particle size calculated by measuring the sample mass wi of each particle size division i using predetermined sieves with different sieve meshes (mesh opening dimensions) and weighting the representative value of each particle size division by the mass fraction of each particle size division.

[0023] (Petroleum-based additive addition process) The petroleum-based additive addition process is a process of adding a petroleum-based additive to a solid carbon resource as a spontaneous heat generation inhibitor. The petroleum-based additive addition process is preferably a process of adding a petroleum-based additive to a solid carbon resource as a spontaneous heat generation inhibitor at 20 to 80°C or less. When adding a pretreated petroleum-based additive to a pretreated solid carbon resource, the amount of petroleum-based additive added relative to the solid carbon resource is 0.1% or more by mass, preferably 1.0% or more, and more preferably 5.0% or more. If the amount of petroleum-based additive is too small, the spontaneous heat generation inhibitory effect of the solid carbon resource cannot be obtained. There is no upper limit to the amount of petroleum-based additive added, but from a cost perspective, a mass ratio of 40% or less relative to the solid carbon resource is preferred, more preferably 30% or less, and even more preferably 20% or less. The petroleum-based additive is added, for example, by putting the solid carbon resource and the petroleum-based additive into a mixer. The temperature at which the petroleum-based additive is added to the solid carbon resource is preferably 80° C. or lower, more preferably 60° C. or lower, and more preferably 40° C. or lower. There is no need to set a lower limit temperature, but from the perspective of actual operating conditions, a temperature of 10° C. or higher is preferred, and 20° C. or higher is more preferred.

[0024] (Mixing Process) The mixing process is a process of mixing a solid carbon resource with a petroleum-based additive. The mixing process is performed after adding the petroleum-based additive to the solid carbon resource, and the petroleum-based additive is mixed thoroughly so that it is distributed evenly throughout the solid carbon resource. When the amount of solid carbon resource is small, both (the solid carbon resource and the petroleum-based additive) are placed in a single container, sealed, and mixed by shaking. When the amount of solid carbon resource is large, both are placed in a mixer or the like and mixed by shaking or rotating. When handling a larger amount of solid carbon resource, in addition to using a mixer or the like, it is recommended to spray the petroleum-based additive on the solid carbon resource (for example, one being stacked in a yard or one stored in a yard). By spraying the petroleum-based additive on the solid carbon resource, the above-mentioned adding process and mixing process can be performed at the same time. Furthermore, after spraying, an additional mixing process may be performed using heavy machinery or the like.

[0025] (Storage process) The storage process is a process of storing the solid carbon resource to which the petroleum-based additive has been added. The solid carbon resource to which the petroleum-based additive has been added (hereinafter also referred to as the solid carbon resource after addition) has suppressed spontaneous heat generation, and therefore can be stored in a yard, storage tank, or the like for a predetermined period of time. The petroleum-based additive is a by-product of petroleum-based heavy oil or petroleum refining, and has a structure similar to fossil fuels. Therefore, the solid carbon resource (e.g., coal, etc.) with suppressed heat generation can be used as fuel for a power generation device or as a raw material for coke production.

[0026] The present invention provides a method for suppressing spontaneous heat generation of a solid carbon resource, and a method for storing a solid carbon resource using the same, which includes adding a petroleum-based additive to the solid carbon resource. According to the present invention, the petroleum-based additive is a by-product of petroleum-based heavy oil or petroleum refining, and is therefore available at low cost. Adding the petroleum-based additive to the solid carbon resource provides a spontaneous heat generation suppression effect, making the method easy to carry out.

[0027] Second Embodiment This embodiment further includes a heating step between the mixing step (or the petroleum-based additive addition step if the mixing step is omitted) and the storage step in the first embodiment. In the first embodiment described above, the addition of the petroleum-based additive reduces the spontaneous heat generation of the solid carbon resource. The inventors discovered that the spontaneous heat generation of the solid carbon resource can be further suppressed by further heating the solid carbon resource in an inert gas atmosphere after adding the petroleum-based additive. The inert gas atmosphere is used because heating the solid carbon resource in the atmosphere may result in combustion. That is, in the second embodiment, it is preferable to first perform a pre-treatment step of the solid carbon resource and a pre-treatment step of the petroleum-based additive, then a petroleum-based additive addition step, then a mixing step, then a heating step, and then a storage step. From the perspective of suppressing spontaneous heat generation of the solid carbon resource, it is sufficient to perform at least the petroleum-based additive addition step. If storage is also performed, it is preferable to perform the storage step subsequently. From the perspective of further suppressing spontaneous heat generation of the solid carbon resource, it is preferable to perform a heating step. However, in order to obtain the maximum effect of this embodiment, it is preferable to perform the above-mentioned steps. Since the steps other than the heating step are the same as those in the first embodiment, the explanation will be omitted, and the heating step will be described in detail below.

[0028] (Heating Process) The heating process is a process of heating the solid carbon resource to which the petroleum-based additive has been added under an inert gas atmosphere. That is, in the heating process, the added solid carbon resource is placed in a heating furnace filled with inert gas, and the added solid carbon resource is heated using the heating furnace. The heating process renders the added solid carbon resource in an inert state, further reducing its spontaneous heat generation. This heating process does not require the use of chemicals, etc., and therefore reduces costs. Furthermore, inert gases such as nitrogen gas have a high supply stability and are simple to operate, allowing for simplified processing. Thus, by adding a heating process to the first embodiment in which the solid carbon resource to which the petroleum-based additive has been added is heated under an inert gas atmosphere, the spontaneous heat generation of the solid carbon resource is further reduced, making it possible to implement a relatively low-cost and simple method for suppressing spontaneous heat generation of a solid carbon resource and a solid carbon resource storage method using the same.

[0029] The heat treatment temperature of the added solid carbon resource is preferably 20°C or higher, more preferably 40°C or higher, more preferably 60°C or higher, more preferably 80°C or higher, more preferably 120°C or higher, and more preferably 200°C or higher. However, if the heat treatment temperature exceeds the carbonization temperature during production of the solid carbon resource, carbonization of the added solid carbon resource is promoted, and there is a risk of the structure changing. Therefore, the carbonization temperature during production of coke from the added solid carbon resource should be set as the upper limit. The carbonization temperature is, for example, 600 to 1000°C. Therefore, the heat treatment temperature is preferably 1000°C or lower, more preferably 800°C or lower, and more preferably 600°C or lower.

[0030] The heat treatment time is preferably 1 hour or more, taking into consideration that the oxidation inhibition reaction is carried out sufficiently. There is no upper limit, but it can be, for example, 1 hour or more and 168 hours or less, preferably 1 hour or more and 168 hours or less, more preferably 1 hour or more and 72 hours or less, and even more preferably 12 hours or more and 72 hours or less. That is, the heat treatment time is preferably 1 hour or more, more preferably 12 hours or more. Furthermore, the heat treatment time is preferably 168 hours or less, more preferably 72 hours or less.

[0031] The atmosphere during the heat treatment is an inert gas atmosphere, such as nitrogen gas or argon gas, in order to prevent combustion of the solid carbon resource after addition.

[0032] When solid carbon resources containing petroleum-based additives are heat-treated under an inert gas atmosphere, the structure of the solid carbon resources changes due to the heat treatment, making them inactive and further suppressing their spontaneous heat generation. Therefore, even if the solid carbon resources are stored in yards or storage tanks after heat treatment, fires due to spontaneous combustion can be prevented.

[0033] The method for suppressing spontaneous heat generation of a solid carbon resource according to the present invention will be specifically described below with reference to examples. Note that the examples shown below are merely examples of the method for suppressing spontaneous heat generation of a solid carbon resource, and the present invention is not limited to the examples below.

[0034] (Example 1) Biomass charcoal derived from acacia (acacia wood), which has high heat generation, was used as the solid carbon resource. Each of the four tests (Test Nos. 1 to 4) shown in Table 1 below was evaluated using a spontaneous heat evaluation device. The carbonization temperature of the biomass charcoal used in the tests is unknown, but since the temperature of the material at the kiln outlet was 595°C, it was heated to at least 595°C or higher. Petroleum-based pitch was used as the petroleum-based additive. This petroleum-based pitch was obtained by thermally decomposing the vacuum distillation residue of petroleum, the raw material, using heated steam at 600°C or higher. These solid carbon resources and the petroleum-based additives to be added were each crushed in a granulator using a metal rod and classified using two sieves with 1.0 mm and 1.7 mm mesh sizes to obtain particles in the particle size range of 1.0 mm or more and less than 1.7 mm (over the 1.0 mm mesh sieve and under the 1.7 mm mesh sieve). 0 g, 0.05 g, 0.10 g, and 0.20 g of petroleum-based additives were added to 1 g of classified biomass charcoal at 20 ° C., and the mixture was shaken and mixed in a sealed container (Tests Nos. 1 to 4).

[0035]

[0036] The mixed sample was filled into a sample container built into a spontaneous ignition tester (Shimadzu Corporation, SIT-2), and the spontaneous ignition potential of each sample in Test Nos. 1 to 4 was measured using the spontaneous ignition tester. After replacing the atmosphere inside the tester with a nitrogen atmosphere, the sample was heated externally until the temperature reached 130°C. After confirming that the sample temperature had reached 130°C, the atmosphere inside the tester was switched from nitrogen to air, and the external heating was turned off. This point was designated as the test start time, and the temperature-time behavior due to spontaneous heating of the sample was confirmed. Specifically, the sample temperature was measured every 5 seconds, and a temperature-time (vertical axis - horizontal axis) heating curve was obtained.

[0037] Here, because petroleum-based additives have a large heat capacity, their addition is thought to slow the heating rate. This makes it difficult to distinguish whether the delayed heating rate in the heating curve obtained with the spontaneous heating evaluation device is due to the heat capacity of the petroleum-based additive or the interaction between the petroleum-based additive and the solid carbon resource. Therefore, we assumed that the heating rates of the petroleum-based additive and the solid carbon resource were the same, and corrected the obtained heating curve to eliminate the effect of the delayed heating rate due to the heat capacity of the petroleum-based additive. Specifically, the heating rate (dT / dt) was calculated by differentiating the heating curve obtained by measurement. The heating rate was then divided by the mass of the solid carbon resource + petroleum-based additive to determine the heating rate per unit mass of the mixture of the solid carbon resource (biomass charcoal) and the petroleum-based additive. For example, if 20 mass% of the petroleum-based additive was added, the heating rate (dT / dt) was divided by 1.2. The heating rate per unit mass of the solid carbon resource was integrated and the temperature-time curve (hereinafter also referred to as the corrected heating curve) was calculated. The spontaneous heat generation of each sample was evaluated based on the time required for the sample temperature shown on the corrected heating curve to reach 200°C from 130°C (hereinafter also referred to as T200). The larger the T200 value, the more suppressed the spontaneous heat generation.

[0038] Figure 1 is a graph showing the corrected heating curves for Test Nos. 1 to 4 (Comparative Example 1, Inventive Examples 1 to 3). Figure 2 is a graph comparing the T200 values ​​calculated from the corrected heating curves (Figure 1). More specifically, the graph shows the T200 delay time for each Inventive Example (T200 for Inventive Example - T200 for Comparative Example 1) relative to the T200 for Comparative Example 1. Table 1 shows the T200 values. As shown in Figure 2, the T200 values ​​indicate that Test Nos. 2 to 4 (Inventive Examples 1 to 3) all exhibited reduced spontaneous heating properties compared to Test No. 1 (Comparative Example 1), which did not contain a petroleum-based additive. In this test, the sample was preheated to 130°C, resulting in a faster heating rate thereafter (i.e., an accelerated test was performed). For this reason, for example, the difference in T200 between Invention Example 1 and Comparative Example 1 is 3 minutes, but in an actual storage site (i.e., in an environment where no accelerated testing is performed), it is thought that T200 of Invention Example 1 will be 3 minutes or more longer than T200 of Comparative Example 1. Therefore, Invention Example 1 exhibits a sufficient effect of suppressing spontaneous heat generation.

[0039] (Example 2) The same solid carbon resource (acacia-derived (acacia wood) biomass charcoal) and petroleum-based additive (petroleum-based pitch) as in Example 1 were each pulverized and classified to a particle size within the range of 1.0 mm or more and less than 1.7 mm. The petroleum-based additive was added at 0.2 g or 0.05 g per 1 g of solid carbon resource (biomass charcoal) at 20°C and mixed. The samples were then heated for 12 hours under a nitrogen atmosphere at the temperatures shown in Table 2 below. After each sample was allowed to cool to room temperature (20°C), the temperature rise curves of each sample after this treatment were measured using the spontaneous combustion evaluation device (SIT-2) in the same manner as in Example 1, and corrections were made in the same manner as in Example 1. Figure 3 is a graph showing the corrected temperature rise curves of Test No. 4 (Invention Example 3) of Example 1 and Test Nos. 5 to 8 (Invention Examples 4 to 7) of Example 2. Figure 4 is a graph showing the corrected temperature rise curves of Test No. 1 of Example 1. 1 is a graph comparing the T200 values ​​calculated from the corrected temperature rise curves of Test Nos. 4 (Invention Example 3) and Test Nos. 5 to 7 (Invention Examples 4 to 6) of Example 2. More specifically, the graph shows the T200 delay time of each Inventive Example (T200 of Inventive Example - T200 of Comparative Example 1) based on the T200 of Comparative Example 1. Table 2 shows the T200 values ​​(Table 1 shows the values ​​for Inventive Example 3).

[0040]

[0041] The obtained temperature rise curves revealed that the higher the heat treatment temperature, the gentler the slope of the corrected temperature rise curve. This was particularly evident at heat treatment temperatures above 80°C (Invention Examples 5-7), significantly reducing spontaneous heat generation. Furthermore, in Invention Example 7 (heat treatment temperature 200°C), spontaneous heat generation decreased as shown in Figure 3, making it impossible to calculate T200. These findings suggest that the higher the heat treatment temperature, the more enhanced the chemical interaction between the petroleum-based additive and the solid carbon resource, thereby enhancing the effect of suppressing spontaneous heat generation. Furthermore, comparing Invention Example 8 (Example 2) with Invention Example 3 (Example 1), Invention Example 8, which underwent heat treatment, had a higher T200 value than Test Invention Example 3 (not underwent heat treatment), which contained a higher amount of petroleum-based additive, demonstrating a greater suppression of spontaneous heat generation. From these findings, it can be concluded that adding a heat treatment step can achieve the effect of suppressing spontaneous heat generation even with a reduced amount of petroleum-based additive. When comparing Example 3 and Example 4, T170 (the time it takes for the sample temperature to reach 170°C from 130°C) of Example 4 is longer than T170 of Example 3. Therefore, the heat treatment step of Example 4 sufficiently suppresses spontaneous heating.

[0042] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

Claims

1. A method for suppressing spontaneous heat generation of a solid carbon resource, comprising the step of adding a petroleum-based additive as a spontaneous heat generation inhibitor to the solid carbon resource.

2. The method for suppressing spontaneous heat generation from a solid carbon resource according to claim 1 , wherein the petroleum-based additive is added to the solid carbon resource in an amount of 1% by mass or more.

3. The method for suppressing spontaneous heat generation of a solid carbon resource according to claim 1, further comprising a step of heat-treating the solid carbon resource to which the petroleum-based additive has been added in an inert gas atmosphere at a temperature of 20°C or higher for 1 hour or more.

4. The petroleum-based additive is crushed and classified to have a particle size of less than 5 mm, and then the petroleum-based additive is added to the solid carbon resource as the spontaneous heat generation inhibitor. The method for suppressing spontaneous heat generation of a solid carbon resource according to any one of claims 1 to 3.

5. The solid carbon resource is biomass charcoal. The method for suppressing spontaneous heat generation of a solid carbon resource according to any one of claims 1 to 3.

6. The petroleum-based additive is composed of at least one of solid petroleum-based tar and solid petroleum-based pitch. The method for suppressing spontaneous heat generation of a solid carbon resource according to any one of claims 1 to 3.

7. A method for storing a solid carbon resource, comprising storing a solid carbon resource treated by the method according to any one of claims 1 to 3.