Method for suppressing natural exothermicity of solid carbon resource and method for storing solid carbon resource using the same

Abstract

The natural heat release suppression method of the solid carbon resource includes a step of adding a petroleum-based additive as a natural heat release inhibitor in the solid carbon resource.

Description

Technical Field

[0001] This invention relates to a method for suppressing the natural exothermic reaction of solid carbon resources and a method for storing solid carbon resources using the same method.

[0002] 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. Background Technology

[0003] Solid carbon resources, such as coal and biochar which are expected to be utilized more extensively in the future, are sometimes stored in large quantities in material yards and other locations. Here, because solid carbon resources naturally release heat, their temperature needs to be carefully managed.

[0004] Several techniques have been proposed to suppress the spontaneous heat release of such solid carbon resources. For example, Patent Document 1 discloses a method in which a temperature rise / spontaneous ignition inhibitor comprising at least one substance selected from free radical scavengers and oxygen scavengers is used to reduce the amount of free radicals generated by the reaction of carbon powder with oxygen, thereby suppressing the temperature rise / spontaneous heat release. It is also described that a nonionic surfactant may be included.

[0005] Furthermore, Patent Document 2 discloses a method for manufacturing modified coal, in which spontaneous combustion is suppressed by drying the coal in an atmosphere containing a free radical scavenger containing organic compounds with hydroxyl groups such as alcohols and phenols.

[0006] Furthermore, Patent Document 3 discloses a stabilization method in which coal is heated at a temperature of 100–350°C until the moisture content of the coal is substantially 0% by weight, followed by oxidation treatment, thereby simultaneously dehydrating the coal and preventing spontaneous combustion.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2001-164254

[0010] Patent Document 2: Japanese Patent Application Publication No. 2011-201947

[0011] Patent Document 3: Japanese Patent Application Publication No. 59-074189 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] However, the method described in Patent Document 1 requires the extensive use of specific compounds, which presents a cost problem. For example, adding a considerable amount of nonionic surfactant as an exothermic inhibitor to carbonaceous powders that are widely used in industry could significantly increase manufacturing costs. Furthermore, the method described in Patent Document 2, which involves adding a considerable amount of organic compounds with hydroxyl groups, also presents cost challenges.

[0014] In Patent Document 3, the effect of oxidation treatment in cases where coal is dehydrated and then subjected to special oxidation treatment to suppress exothermic reactions, but dehydration treatment is not required, is unclear.

[0015] In conclusion, previous methods require further improvements in terms of cost and ease of operation.

[0016] The present invention was made in view of the above-mentioned problems, and its object is to provide an inexpensive and simple method for suppressing the natural exothermic reaction of solid carbon resources and a method for storing solid carbon resources using the same.

[0017] Methods for solving problems

[0018] (1) A method for suppressing the natural exothermic reaction of solid carbon resources, comprising the step of adding petroleum-based additives to the solid carbon resources as natural exothermic reaction inhibitors.

[0019] (2) The method for suppressing the natural exothermic reaction of solid carbon resources according to (1), wherein the above-mentioned petroleum-based additives are added to the solid carbon resources at a mass ratio of 1% or more.

[0020] (3) The method for suppressing the natural exothermic reaction of solid carbon resources according to (1) or (2) further includes a step of heating the solid carbon resources with the above-mentioned petroleum-based additives in an inert gas atmosphere at a temperature of 20°C or higher for more than 1 hour.

[0021] (4) A method for storing solid carbon resources, wherein the solid carbon resources treated by any one of (1) to (3) are stored.

[0022] Invention Effects

[0023] According to the present invention, by including a process of adding petroleum-based additives to solid carbon resources, the natural exothermicity of solid carbon resources can be easily reduced at low cost. Attached Figure Description

[0024] Figure 1 It is a graph showing the corrected temperature rise curves of tests No.1 to 4 (Comparative Example 1, Invention Examples 1 to 3).

[0025] Figure 2It is a graph comparing the T200 delay time values ​​calculated from the corrected heating curves of Tests No.1 to 4 (Comparative Example 1, Invention Examples 1 to 3).

[0026] Figure 3 It is a graph showing the corrected temperature rise curves of Test No. 4 (Example 3) of Example 1 and Tests No. 5 to 8 (Examples 4 to 7) of Example 2.

[0027] Figure 4 It is a graph comparing the T200 delay time values ​​calculated from the corrected heating curves of Test No. 4 (Example 3 of the Invention) in Example 1 and Tests No. 5 to 7 (Examples 4 to 6 of the Invention) in Example 2. Detailed Implementation

[0028] In order to solve the above-mentioned problems, the inventors conducted in-depth research and repeatedly experimented with petroleum-based additives, which led to the invention.

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] It should be noted that in this specification, "solid carbon resources" refers to any solid material with carbon as its main component, without any particular limitation. Examples include raw materials for coke production, charcoal used as fuel in power generation and converters, and charcoal materials used as heating agents. Examples of charcoal materials include fossil resources (anthracite, bituminous coal, sub-bituminous coal, lignite, peat, etc.) and biologically derived organic resources (biomass itself, and biochar produced by thermal treatment of biomass (charcoal, black pellets, etc., carbonized or semi-carbonized biomass)). Furthermore, in this specification, "petroleum-based heavy oil" refers to crude oil with a heavy component, high viscosity, and high specific gravity obtained through refining petroleum; "petroleum-based tar" refers to a black to brown oily substance with viscous gas produced by the thermal decomposition of petroleum or petroleum-derived substances; and "petroleum-based asphalt" refers to the residual components after refining crude oil from petroleum, gasoline, etc., or the residue obtained by vacuum distillation of petroleum. In addition, petroleum-based heavy oils are liquid at room temperature (20°C), while petroleum-based tar and petroleum-based bitumen are solid at room temperature (20°C).

[0031] Petroleum-based additives consist of at least one of the following: petroleum-based heavy oil, petroleum-based tar, and petroleum-based asphalt. Petroleum-based additives are petroleum-derived additives and are petroleum-based additives in general.

[0032] The petroleum-based additive is preferably composed of at least one of petroleum-based tar and petroleum-based asphalt, more preferably composed of at least one of petroleum-based heavy oil and petroleum-based asphalt, and even more preferably composed of petroleum-based asphalt.

[0033] This invention relates to a method for suppressing the natural exothermic reaction of solid carbon resources, including the step of adding petroleum-based additives to solid carbon resources, and a method for storing solid carbon resources treated using this method. Petroleum-based additives have historically been used industrially as coal binders when coal is used as a raw material for coking. Specifically, they are used as binders that exhibit binding properties at high temperatures (350°C to 550°C) to compensate for the low expansion properties of coal (such as non-caking coal). However, the inventors have recently discovered that petroleum-based additives, by being added to and mixed with solid carbon resources, can suppress the natural exothermic reaction of the solid carbon resources. That is, in this invention, petroleum-based additives are used as additives for suppressing natural exothermic reaction (natural exothermic inhibitors).

[0034] The coke manufacturing process in the ironmaking process of the steel industry typically involves, for example, a sequential process of loading onto a ship, storing coal (in a stockyard, etc.), blending coal, crushing coal, forming coal, and charging coke into the furnace. Petroleum-based additives, acting as binders, are added to the coal, which has been blended with raw coal in a specified amount, after the blending process (see Japanese Patent Application Laid-Open Nos. 2014-70125, Japanese Patent Application Laid-Open Nos. 2008-120973, etc.). In contrast, in the ironmaking process of the steel industry, when petroleum-based additives are used as a natural exothermic inhibitor as in this invention, it is preferable to perform this process at a certain stage between the loading and blending processes (including the aforementioned transfer and conveying processes between the loading and blending processes). More preferably, the addition of petroleum-based additives is carried out in one or both of the following stages: after the loading process and before the coal storage process (e.g., before coal (raw coal) is unloaded from the ship and moved to a coal storage yard or similar facility), and after the coal storage process and before the coal blending process (e.g., before coal is moved from the coal storage yard to the coal blending yard). It should be noted that when using petroleum-based additives as natural exothermic inhibitors, their effects can be enjoyed regardless of when they are added before the coke oven charging process; however, by adding them upstream in the process flow, the possibility of spontaneous combustion downstream can be suppressed. Except for ironmaking processes in the steel industry (e.g., coal-fired power generation processes), when using petroleum-based additives as natural exothermic inhibitors of coal, they are added before the process of using coal as fuel. For example, they can be added after the loading process and before the coal storage process, during coal storage in the yard, during the process of moving coal from the yard to the coal storage bin, during coal storage in the coal storage bin, or during the coal blending process; addition upstream is preferred. More specifically, natural exothermic inhibitors can be mixed into the coal before storage in the stockyard or coal seam, or natural exothermic inhibitors can be added to the coal during storage (in its storage state).

[0035] The exothermic nature of solid carbon resources is due to the abundant and diverse oxidation reactions driven by highly reactive free radicals within them. It is believed that because petroleum-based additives (at least one of petroleum-based heavy oil, petroleum-based bitumen, and petroleum-based tar) contain numerous hydrogen-donating structures such as naphthalene rings, this hydrogen-donating property creates certain chemical interactions (free radical capture) with solid carbon resources, promoting oxidation inhibition reactions and thus exhibiting an exothermic inhibitory effect. While it is known that aromatic compounds with hydrogen-donating naphthalene rings enhance the softening and melting properties of coal, their effect on inhibiting the exothermic nature of solid carbon resources is unknown.

[0036] Hereinafter, an example of an embodiment of the present invention will be described in detail.

[0037] <First Implementation>

[0038] In this embodiment, the exothermic suppression treatment of solid carbon resources is achieved by adding petroleum-based additives. Here, it is preferable to pre-treat the solid carbon resources before adding the petroleum-based additives. Furthermore, it is preferable to pre-treat the petroleum-based additives before adding them to the solid carbon resources. Moreover, it is preferable to perform a mixing process and a storage process after adding the petroleum-based additives. That is, in the first embodiment, it is preferable to first perform the pre-treatment process of the solid carbon resources and the pre-treatment process of the petroleum-based additives, then perform the petroleum-based additive addition process, then perform the mixing process, and then perform the storage process. From the viewpoint of suppressing the natural exothermic reaction of solid carbon resources, at least the petroleum-based additive addition process is sufficient; if storage is also performed, it is preferable to then perform the storage process. However, to maximize the benefits of this embodiment, it is preferable to perform each of the above-described processes.

[0039] (Pre-processing of solid carbon resources, pre-processing of petroleum-based additives)

[0040] Pretreatment of solid carbon resources includes, for example, particle size adjustment of the solid carbon resources used as raw materials. Pretreatment of petroleum-based additives includes, for example, particle size adjustment of the petroleum-based additives used as raw materials. Pretreatment of petroleum-based additives is performed as needed. For example, it can be performed when the petroleum-based additives are solid. Particle size adjustment of solid carbon resources and petroleum-based additives can be performed, for example, by crushing or classifying. Crushing can be performed using various crushers such as ball mills, bead mills, mortars, and hammer mills. Furthermore, classification can be performed using dry classifiers such as classifying sieves, gravity classifiers, inertial classifiers, and centrifugal classifiers.

[0041] In this process, to facilitate the oxidation inhibition reaction in a short time, it is preferable to set the particle size of the petroleum-based additive to be relatively small to promote the oxidation inhibition reaction. Specifically, the petroleum-based additive is preferably less than 5 mm in particle size, and more preferably less than 2 mm. Furthermore, when mixing with solid carbon resources, if the petroleum-based additive is too fine, it cannot be mixed well; therefore, the petroleum-based additive is preferably 1 mm or more in particle size. It should be noted that the particle size is defined using a sieve. Particles passing through a sieve with X mm apertures are defined as having a particle size of less than X mm, and particles passing through a sieve without X mm apertures are defined as having a particle size of X mm or more.

[0042] Pretreatment of solid carbon resources is performed as needed. For example, in the mixing process described later, where petroleum-based additives are dispersed among the solid carbon resources, pretreatment of the solid carbon resources is not necessarily required. When mixing is performed using containers, mixers, etc., pretreatment of the solid carbon resources is performed to ensure more uniform mixing of the solid carbon resources and petroleum-based additives. The average particle size of the solid carbon resources is preferably set to 0.5 times or more and 1.5 times or less of the average particle size of the petroleum-based additives, more preferably to the same level as the average particle size of the petroleum-based additives (0.8 times or more and 1.2 times or less). That is, the average particle size of the solid carbon resources is preferably set to 0.5 times or more of the average particle size of the petroleum-based additives, more preferably 0.8 times or more. Furthermore, the average particle size of the solid carbon resources is preferably set to 1.5 times or less of the average particle size of the petroleum-based additives, more preferably 1.2 times or less. Here, the so-called average particle size refers to the arithmetic mean particle size calculated by using specified sieves with different sieve apertures (opening sizes), measuring the sample mass wi of each particle size segment i, and weighting the representative values ​​of each particle size segment by the mass fraction of each particle size segment.

[0043] (Petroleum-based additive addition process)

[0044] The petroleum-based additive addition process involves adding petroleum-based additives to solid carbon resources as a natural exothermic inhibitor. Preferably, the petroleum-based additive addition process involves adding the additives to the solid carbon resources at a temperature below 20–80°C as a natural exothermic inhibitor.

[0045] When adding pretreated petroleum-based additives to pretreated solid carbon resources, the amount of petroleum-based additives relative to the solid carbon resources is set to 0.1% or more by mass, preferably 1.0% or more, and more preferably 5.0% or more. If the amount of petroleum-based additives is too small, the natural exothermic suppression effect of the solid carbon resources will not be obtained. There is no upper limit to the amount of petroleum-based additives added, but from a cost perspective, it is preferably 40% or less by mass relative to the solid carbon resources, more preferably 30% or less, and even more preferably 20% or less. The petroleum-based additives are added, for example, by inputting the solid carbon resources and petroleum-based additives into a mixer. The temperature at which the petroleum-based additives are added to the solid carbon resources is preferably 80°C or less, more preferably 60°C or less, and even more preferably 40°C or less. It is not necessary to set a lower temperature limit, but from a practical operating perspective, it is preferably 10°C or more, and more preferably 20°C or more.

[0046] (Mixed Process)

[0047] The mixing process involves mixing solid carbon resources with petroleum-based additives. This process occurs after the addition of petroleum-based additives to the solid carbon resources, ensuring thorough mixing in a manner that makes the petroleum-based additives and solid carbon resources equal. When the solid carbon resources are in small quantities, both (solid carbon resources and petroleum-based additives) are placed in a sealed container and agitated to mix. When the solid carbon resources are in large quantities, they are fed into a mixer or similar device and mixed by agitation or rotation. When processing even larger quantities of solid carbon resources, in addition to using a mixer, the petroleum-based additives can be dispersed into the solid carbon resources (e.g., solid carbon resources being stockpiled in a storage yard, or solid carbon resources stored in a storage yard). By dispersing the additives into the solid carbon resources, both the addition and mixing processes described above can be performed in one step. Furthermore, additional mixing can be performed using heavy equipment after dispersing.

[0048] (Storage process)

[0049] The storage process is the process of storing solid carbon resources with added petroleum-based additives. Solid carbon resources with added petroleum-based additives (hereinafter also referred to as added solid carbon resources) can be stored in stockyards, storage tanks, etc., for a specified period because their exothermic properties are suppressed. Petroleum-based additives are byproducts of petroleum-based heavy oil or petroleum refining and have a structure similar to fossil fuels. Therefore, exothermic-suppressed solid carbon resources (such as coal) can be used directly as fuel for power generation units or as raw materials for coking.

[0050] This invention relates to a method for suppressing the natural exothermic reaction of solid carbon resources, including a step of adding petroleum-based additives to solid carbon resources, and a method for storing solid carbon resources using the same. According to this invention, since the petroleum-based additives are byproducts of petroleum-based heavy oil or petroleum refining, they can be obtained at a low price. The method is simple to implement as long as the petroleum-based additives are added to the solid carbon resources to achieve the effect of suppressing natural exothermic reaction.

[0051] <Second Implementation Method>

[0052] This embodiment further includes a heating step between the mixing step (or, if the mixing step is omitted, the petroleum-based additive addition step) and the storage step in the first embodiment. In the first embodiment described above, the solid carbon resource is reduced in its natural exothermic state by adding the petroleum-based additive. The inventors have discovered that by further heating the solid carbon resource in an inert gas atmosphere after adding the petroleum-based additive, the natural exothermic nature of the solid carbon resource can be further suppressed. An inert gas atmosphere is chosen because the solid carbon resource may combust if heated in the atmosphere. That is, in the second embodiment, it is preferable to first perform a pretreatment step for the solid carbon resource and a pretreatment step for the petroleum-based additive, then perform a petroleum-based additive addition step, then a mixing step, then a heating step, and then a storage step. From the viewpoint of suppressing the natural exothermic nature 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 then perform the storage step. From the viewpoint of further suppressing the natural exothermic nature of the solid carbon resource, it is preferable to perform the heating step. However, in order to maximize the effect of this embodiment, it is preferable to perform each of the above-described steps. Except for the heating process, since the process is the same as that in the first embodiment, the description will be omitted. The heating process will be described in detail below.

[0053] (Heating process)

[0054] The heating process involves heating solid carbon resources with added petroleum-based additives in an inert gas atmosphere. Specifically, in this process, the added solid carbon resources are placed in a furnace filled with an inert gas and heated. Through this heating treatment, the added solid carbon resources become inert, further reducing their exothermic nature. Since there is no need to use reagents in this heating process, costs can be controlled. Furthermore, the supply stability of inert gases such as nitrogen is high, and the operation is simple, allowing for easy processing. Thus, by adding a heating process in the first embodiment to heat solid carbon resources with added petroleum-based additives in an inert gas atmosphere, the exothermic nature of the solid carbon resources is further reduced, enabling the implementation of a relatively low-cost and simple method for suppressing the exothermic nature of solid carbon resources and a method for storing solid carbon resources using this method.

[0055] The heating temperature for adding solid carbon resources 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 heating temperature exceeds the carbonization temperature during the production of solid carbon resources, it may promote the carbonization of the added solid carbon resources and cause structural changes. Therefore, it is best to set the carbonization temperature during the production of coke from the added solid carbon resources as an upper limit. The carbonization temperature is, for example, 600 to 1000°C. Therefore, the heating temperature is preferably 1000°C or lower, more preferably 800°C or lower, and more preferably 600°C or lower.

[0056] To ensure the oxidation inhibition reaction proceeds sufficiently, the heat treatment time is preferably set to 1 hour or more. There is no upper limit, but it can be set to 1 hour or more but less than 168 hours, preferably 1 hour or more but less than 168 hours, more preferably 1 hour or more but less than 72 hours, and even more preferably 12 hours or more but less than 72 hours. 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 less than 168 hours, more preferably less than 72 hours.

[0057] From the perspective of preventing the combustion of solid carbon resources after addition, the atmosphere during heat treatment is set to an inert gas atmosphere. Nitrogen, argon, etc. can be used as the inert gas in this case.

[0058] The substance obtained by heating solid carbon resources with added petroleum-based additives in an inert gas atmosphere undergoes structural changes during heating, transforming the solid carbon resources into an inert state and further suppressing spontaneous exothermic reactions. Therefore, even if stored directly in material yards or storage tanks after heating treatment, fires caused by spontaneous combustion can be prevented.

[0059] Example

[0060] The following embodiments illustrate the method for suppressing the natural exothermic reaction of solid carbon resources according to the present invention. It should be noted that the embodiments shown below are merely examples of the method for suppressing the exothermic reaction of solid carbon resources, and the present invention is not limited to the embodiments described below.

[0061] (Example 1)

[0062] Biochar from acacia wood, a source of high exothermicity, was used as the solid carbon resource. Four tests (Tests No. 1-4) shown in Table 1 below were evaluated using a natural exothermic evaluation device. The carbonization temperature of the biochar 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. Petroleum-based additives were used. This petroleum-based asphalt was obtained by thermally decomposing the residue of vacuum distillation of petroleum as a raw material using heated steam at 600°C or higher. The solid carbon resources and the added petroleum-based additives were pulverized in a pellet mill using a gold rod, and graded using two sieves with apertures of 1.0 mm and 1.7 mm. Materials with a particle size range of 1.0 mm or larger and smaller than 1.7 mm (the upper part of the 1.0 mm sieve and the lower part of the 1.7 mm sieve) were used. 0g, 0.05g, 0.10g and 0.20g of petroleum-based additives were added to 1g of graded biochar at 20℃, and the mixture was shaken in a sealed container to mix (Experiments No.1 to No.4).

[0063] Table 1

[0064]

[0065] The mixed sample was filled into a sample container within a built-in spontaneous ignition tester (Spontaneousignition tester, manufactured by Shimadzu Corporation, SIT-2), and the spontaneous ignition of each sample in Tests No. 1 to No. 4 was determined using the spontaneous ignition tester. After purging the test chamber with a nitrogen atmosphere, the sample temperature was raised to 130°C via external heating. Once the sample temperature reached 130°C, the atmosphere inside the test chamber was switched from nitrogen to air, and external heating was interrupted. This moment was set as the test start time, and the temperature-time behavior of the sample due to spontaneous ignition was confirmed. Specifically, the sample temperature was measured every 5 seconds, obtaining a temperature-time (vertical axis-horizontal axis) temperature rise curve.

[0066] Here, it is assumed that the heating rate is delayed due to the high heat capacity of petroleum-based additives. Therefore, it becomes indistinguishable whether the delay in the heating rate of the heating curve obtained from the exothermic evaluation device is caused by the heat capacity of the petroleum-based additives or by the interaction between the petroleum-based additives and the solid carbon resource. Thus, by assuming that the heating rates of the petroleum-based additives and the solid carbon resource are the same, and correcting the obtained heating curve, the effect of the heating rate delay caused by the heat capacity of the petroleum-based additives is eliminated. Specifically, the heating rate (dT / dt) is calculated by differentiating the measured heating curve. The heating rate per unit mass of the mixture of solid carbon resource (biochar) and petroleum-based additives is obtained by dividing this heating rate by the mass of (solid carbon resource + petroleum-based additives). For example, when 20% by mass of petroleum-based additives is added, the heating rate (dT / dt) is divided by 1.2. The heating rate per unit mass of the solid carbon resource is integrated to reconstruct the temperature-time curve (hereinafter also referred to as the corrected heating curve). The spontaneous exothermicity of each sample is evaluated based on the time taken (hereinafter referred to as T200) from 130°C to 200°C as shown by the corrected temperature rise curve. It should be noted that the larger the value of T200, the more the spontaneous exothermicity is suppressed.

[0067] Figure 1 It is a graph showing the corrected temperature rise curves of tests No.1 to 4 (Comparative Example 1, Invention Examples 1 to 3). Figure 2 It is the corrected temperature rise curve ( Figure 1 A graph comparing the calculated T200 values. More specifically, it is a graph showing the delay time of T200 for each inventive example (T200 of the inventive example - T200 of Comparative Example 1) based on T200 of Comparative Example 1. T200 is shown in Table 1.

[0068] like Figure 2 As shown, the T200 value indicates that the natural exothermic properties of Tests No. 2 to 4 (Invention Examples 1 to 3) are all reduced compared to Test No. 1 (Comparative Example 1) without the addition of petroleum-based additives. It should be noted that in this test, since the sample was preheated to 130°C, the subsequent heating rate was accelerated (i.e., an accelerated test was conducted). Therefore, for example, the difference between T200 of Invention Example 1 and T200 of Comparative Example 1 is 3 minutes, but it is considered that in actual storage conditions (i.e., under conditions without accelerated testing), T200 of Invention Example 1 is extended by more than 3 minutes compared to T200 of Comparative Example 1. Therefore, Invention Example 1 effectively suppresses natural exothermic properties.

[0069] (Example 2)

[0070] The same solid carbon resources (biochar from acacia wood) and petroleum-based additives (petroleum-based pitch) as in Example 1 were pulverized and graded to a particle size range of 1.0 mm or more and 1.7 mm or less. For every 1 g of solid carbon resources (biochar), 0.2 g of petroleum-based additive or 0.05 g of petroleum-based additive was added at 20°C, and the mixture was then stirred. The mixture was then heated for 12 hours at the temperatures shown in Table 2 below under a nitrogen atmosphere. After each sample was cooled to room temperature (20°C), the temperature rise curve of each treated sample was measured using a spontaneous combustion assessment device (SIT-2) in the same manner as in Example 1, and the same corrections were performed as in Example 1. Figure 3 This is a graph showing the corrected temperature rise curves for Test No. 4 (Example 3) of Example 1 and Tests No. 5 to 8 (Examples 4 to 7) of Example 2. Furthermore, Figure 4 This is a graph comparing the T200 values ​​calculated from the corrected heating curves for Test No. 4 (Example 3) of Example 1 and Tests No. 5 to 7 (Examples 4 to 6) of Example 2. More specifically, it is a graph showing the delay time of T200 for each example of the invention (T200 of the example of the invention - T200 of the example of comparison 1) based on T200 of Comparative Example 1. T200 is shown in Table 2 (and in Table 1 for Example 3).

[0071] Table 2

[0072]

[0073] The obtained heating curves clearly show that the higher the heat treatment temperature, the gentler the slope of the corrected heating curve becomes. This is especially true at heat treatment temperatures above 80°C (Examples 5-7), where the slope becomes significantly gentler, and the natural exothermic effect is greatly reduced. Furthermore, in Example 7 (heat treatment temperature of 200°C), due to... Figure 3 As shown, the natural exothermic reaction decreases, therefore T200 cannot be calculated. From these points, it can be concluded that the higher the heat treatment temperature, the more it promotes the chemical interaction between petroleum-based additives and solid carbon resources, and the more effectively it suppresses natural exothermic reaction.

[0074] Furthermore, comparing Invention Example 8 of Example 2 with Invention Example 3 of Example 1, Invention Example 8, which underwent heat treatment, had a smaller amount of petroleum-based additive, but a larger T200 value compared to Invention Example 3, which did not undergo heat treatment and had a larger amount of petroleum-based additive, thus suppressing exothermic reactions. From the above, it can be concluded that by performing a heat treatment process, even with a reduced amount of petroleum-based additive, an exothermic reaction suppression effect can be achieved. It should be noted that, when comparing Invention Example 3 with Invention Example 4, the T170 (the time it takes for the sample temperature to rise from 130°C to 170°C) in Invention Example 4 is longer than that in Invention Example 3. Therefore, the heat treatment process in Invention Example 4 effectively suppresses exothermic reactions.

[0075] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to these examples. Anyone skilled in the art will understand that various modifications or alterations can be conceived within the scope of the technical concept described in the claims, and these modifications are also within the technical scope of the present invention.

Claims

1. A method for suppressing the natural exothermic reaction of solid carbon resources, comprising the steps of adding the petroleum-based additive as a natural exothermic inhibitor to the solid carbon resources after the petroleum-based additive has been over-crushed and classified to set the particle size of the petroleum-based additive to be greater than 1 mm and less than 5 mm. in, The average particle size of the solid carbon resource is set to be at least 0.5 times and within 1.5 times the average particle size of the petroleum-based additives. The petroleum-based additive is composed of at least one of petroleum-based tar and petroleum-based asphalt.

2. The method for suppressing the natural exothermic reaction of solid carbon resources according to claim 1, wherein, The solid carbon resource is added with petroleum-based additives at a mass ratio of 1% or more.

3. The method for suppressing the natural exothermic reaction of solid carbon resources according to claim 1, further comprising a step of heating the solid carbon resources with the added petroleum-based additives at a temperature above 20°C for more than 1 hour in an inert gas atmosphere.

4. The method for suppressing the natural exothermic reaction of solid carbon resources according to any one of claims 1 to 3, wherein, The solid carbon resource is biochar.

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