Method for storing carbonized biomass

Abstract

The method for storing carbonized biomass according to at least one embodiment of the present disclosure comprises: a step for forming a first layer (11) containing carbonized biomass (10) in the ground; and a step for covering the top of the first layer (11) formed in the ground with a second layer (12) having a thickness of 50 cm or more. In the step of covering the top of the first layer (11) with the second layer (12), the top of the first layer (11) is covered with the second layer (12) having a thickness of 50 cm or more, which is formed of soil that consists only of soil material, or soil that is mainly composed of soil and containing gravel.

Description

Storage Method of Carbonized Biomass

[0001] This disclosure relates to a method for storing carbonized biomass. This application claims priority based on Japanese Patent Application No. 2025-024938 filed with the Japan Patent Office on February 19, 2025, and incorporates its content herein by reference.

[0002] As a countermeasure against global warming caused by greenhouse gases such as carbon dioxide and methane, efforts have been made to reduce the emissions of greenhouse gases. In this activity, carbon credit trading is also carried out, such as purchasing carbon credits representing the amount of greenhouse gas emissions reduced or absorbed in other locations to offset the difficult parts of reducing greenhouse gas emissions. Therefore, it is conceivable to create carbon credits. For example, it is conceivable to create carbon credits by storing biochar (carbonized biomass) derived from biomass. For example, Patent Document 1 discloses burying dried biomass or carbonized biomass in a landfill.

[0003] U.S. Patent Application Publication No. 2023 / 0311178

[0004] If the carbonized biomass decomposes during storage, the amount of carbon held by the carbonized biomass will decrease, so the value as a carbon credit will be damaged, and the credibility, that is, the sustainability, as a carbon credit will decrease. However, Patent Document 1 does not disclose what to cover the dried biomass or carbonized biomass placed in the landfill with. Therefore, for example, it is not clear whether the reduction in the carbon retention rate due to decomposition by decay fungi can be reduced.

[0005] In view of the above circumstances, at least one embodiment of this disclosure aims to provide a method for storing carbonized biomass that can maintain a relatively high carbon retention rate in the carbonized biomass for a relatively long period.

[0006] The method for storing carbonized biomass according to at least one embodiment of the present disclosure includes a step of forming a first layer containing carbonized biomass in the ground, and a step of covering the first layer formed in the ground with a second layer having a thickness of 50 cm or more. In the step of covering with the second layer, the second layer is formed of soil only with a thickness of 50 cm or more on the first layer, or soil mainly containing gravel to cover the first layer.

[0007] According to at least one embodiment of the present disclosure, the residual rate of carbon in the stored carbonized biomass can be maintained in a relatively high state for a relatively long period.

[0008] In the method for storing carbonized biomass according to some embodiments, it is a diagram schematically showing an example of a storage location of the carbonized biomass to be stored. It is a flowchart showing the processing procedure in the method for storing carbonized biomass according to some embodiments. It is a diagram schematically showing a molded product of carbonized biomass molded in a layered form. It is a diagram schematically showing a molded product of carbonized biomass molded in a块状 form. It is a diagram schematically showing a state where a first layer containing carbonized biomass is formed in a depression. It is a diagram schematically showing a state where the first layer is covered with a second layer formed of soil. It is a diagram schematically showing a state where the first layer is covered with a second layer formed of any one of clay, concrete, asphalt, brick blocks, or concrete blocks. It is a diagram schematically showing a state where a third layer is formed between the first layer and the second layer. It is a diagram showing an embodiment of measuring the oxygen concentration of the first layer. The CO ２ concentration measurement embodiment. It is a diagram showing an embodiment of measuring the CO ２ concentration of the second layer. It is a diagram showing an embodiment of measuring the temperature of the first layer and the second layer. It is a diagram showing an embodiment of measuring the temperature of the first layer and the surroundings of the first layer.

[0009] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of this disclosure, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only describe such arrangements strictly, but also represent states of relative displacement with tolerances, or angles or distances to the extent that the same function is achieved. For example, expressions describing things being in an equal state such as "identical," "equal," and "homogeneous" should not only describe states of being strictly equal, but also represent states where tolerances, or differences to the extent that the same function is achieved, exist. For example, expressions describing shapes such as square shapes or cylindrical shapes should not only describe geometrically precise square shapes or cylindrical shapes, but also represent shapes including concave and concave parts, chamfered parts, etc., to the extent that the same effect is achieved. On the other hand, expressions such as "to possess," "to be equipped with," "to have," "to include," or "to have" a single component are not exclusive expressions that exclude the existence of other components.

[0010] Figure 1 is a schematic diagram showing an example of a storage location for carbonized biomass in a carbonized biomass storage method according to several embodiments. In the carbonized biomass storage method according to several embodiments, the storage location for carbonized biomass is a relatively large depression 1 formed by open-cut mining in the ground 3, such as in a coal mine or other mine. Such depressions 1 are often left unattended, and it is desirable to utilize them effectively.

[0011] Therefore, in some embodiments of the carbonized biomass storage method, carbonized biomass is stored using such depressions 1. The carbonized biomass stored in these embodiments of the carbonized biomass storage method is intended for use as carbon credits.

[0012] If carbonized biomass decomposes during storage, the amount of carbon it holds decreases, impairing its value as a carbon credit and reducing its credibility, or permanence, as a carbon credit. Therefore, in some embodiments of carbonized biomass storage methods, the carbonized biomass is stored in a depression 1 as follows.

[0013] Figure 2 is a flowchart showing the processing steps in a carbonized biomass storage method according to several embodiments. The carbonized biomass storage method according to several embodiments includes a step S1 for generating carbonized biomass, a step S3 for shaping the carbonized biomass, a step S5 for forming a first layer, a step S7 for forming a third layer, a step S9 for covering with a second layer, and a step S11 for monitoring the carbonized biomass.

[0014] <Step S1 for generating carbonized biomass> In the carbonized biomass storage method according to several embodiments, step S1 for generating carbonized biomass is a step for generating carbonized biomass by carbonizing woody biomass. In step S1 for generating carbonized biomass, woody biomass such as sawdust, wood shavings, sawmill residues containing bark, and forest residues generated at sawmills are dried and carbonized to produce carbonized biomass. In step S1 for generating carbonized biomass, woody biomass is dried and then carbonized. In step S1 for generating carbonized biomass, woody biomass is carbonized at a temperature of 290°C or higher and less than 400°C to produce carbonized biomass.

[0015] At carbonization temperatures of around 300°C, cellulose and hemicellulose in woody biomass are decomposed and carbonized, but lignin remains largely undecomposed and uncarbonized. According to several embodiments of carbonized biomass storage methods, the carbonization of lignin in woody biomass can be reduced as much as possible to ensure a sufficient amount of residual carbon, while simultaneously decomposing and carbonizing the cellulose and hemicellulose of the woody biomass. This suppresses decay by brown rot and soft rot fungi, improving the reliability, i.e., permanence, of carbonized biomass as a carbon credit. Furthermore, because lignin acts as an adhesive component, its presence makes it easier for woody biomass to clump together when compacted. According to several embodiments of carbonized biomass storage methods, a relatively large amount of lignin can be retained, making it easier for woody biomass to clump together when compacted, facilitating handling during storage and reducing the storage space required. Moreover, compacting the carbonized biomass reduces voids, thus preventing the invasion of decay fungi and reducing CO2 adsorption by chemical and physical adsorption of oxygen. ２ This can suppress the occurrence of [unclear].

[0016] Furthermore, when the carbonization temperature of carbonized biomass reaches around 400°C, the risk of spontaneous combustion of the carbonized biomass increases. While there are methods to reduce the risk of spontaneous combustion by increasing the carbonization temperature to 600°C or higher, this reduces the amount of residual carbon after carbonization, thus decreasing the amount of credit. According to several embodiments of carbonized biomass storage methods, the risk of spontaneous combustion can be reduced while maintaining the amount of credit by keeping the carbonization temperature below 400°C.

[0017] <Step S3 for molding carbonized biomass> Figure 3A is a schematic diagram showing a molded product 31 of carbonized biomass 10 molded in layers. Figure 3B is a schematic diagram showing a molded product 31 of carbonized biomass 10 molded in a block shape. In the carbonized biomass storage method according to some embodiments, step S3 for molding carbonized biomass is a step in which the carbonized biomass 10 obtained in step S1 for generating carbonized biomass is molded into a layered or block-shaped molded product 31.

[0018] In step S3, which involves forming the carbonized biomass, the carbonized biomass 10 is formed into a layered or block-shaped molded product 31 with a minimum dimension of 1 m or more. For example, as shown in Figure 3A, when the carbonized biomass 10 is formed into a layered molded product 31, in step S3, the minimum dimension of the layered carbonized biomass 10 molded product 31, which is the thickness t, is set to be 1 m or more. For example, as shown in Figure 3B, when the carbonized biomass 10 is formed into a block-shaped molded product 31, in step S3, the vertical dimension x, horizontal dimension y, and height dimension z of the block-shaped carbonized biomass 10 molded product 31 are all set to be 1 m or more. Note that in Figure 3B, for convenience, the shape of the block-shaped carbonized biomass 10 molded product 31 is shown as a rectangular parallelepiped, but the shape of the block-shaped carbonized biomass 10 molded product 31 may be a shape other than a rectangular parallelepiped.

[0019] According to several embodiments of the carbonized biomass storage method, carbonized biomass 10 is molded into a layered or lump-shaped molded product 31 with a minimum dimension of 1 m or more. As a result, the size of the molded product 31 becomes relatively large, and the surface area per unit volume of the molded product 31 can be relatively reduced. This relatively reduces the penetration of oxygen from the surface of the molded product 31, thereby suppressing decay and oxidation.

[0020] In some embodiments of the carbonized biomass storage method, in step S3 of forming the carbonized biomass 10, a mixture of at least one of soil 21 or gravel 22 and the carbonized biomass 10 may be formed as a molded product 31. This allows the amount of molded product 31 to be increased by mixing at least one of soil 21 or gravel 22 into the molded product 31, even if the size of the depression 1 etc. forming the first layer 11 is large relative to the amount of carbonized biomass 10 to be stored, thereby filling the depression 1 etc. Furthermore, according to some embodiments of the carbonized biomass storage method, for example, residual gravel after mining in a mine can be mixed with the carbonized biomass 10 to form a molded product 31, thereby processing the residual gravel.

[0021] <Step S5 for forming the first layer> Figure 4 is a schematic diagram showing the state in which the first layer 11 containing carbonized biomass 10 has been formed in the depression 1. In the carbonized biomass storage method according to some embodiments, step S5 for forming the first layer is the step of forming the first layer 11 containing carbonized biomass underground. In step S5 for forming the first layer, as shown in Figure 4, the first layer 11 containing carbonized biomass 10 is formed in the depression 1. In step S5 for forming the first layer, the first layer 11 is formed which includes the molded product 31 formed in step S3 for molding carbonized biomass. The molded product 31 that forms the first layer 11 is not covered with any covering material or the like, and the molded product 31, i.e., the surface of the carbonized biomass 10, is exposed when it is placed underground.

[0022] In step S5, which forms the first layer, the first layer 11 may be formed using carbonized biomass 10. That is, in step S5, which forms the first layer, the molded material 31 may be made without soil 21 or gravel 22 other than carbonized biomass 10, and the first layer 11 may be formed without other materials such as soil, earth, or rocks that fill the spaces between the molded materials 31 in the depressions 1, in addition to the carbonized biomass 10. This makes it possible to increase the amount of carbon credits per unit volume in the first layer 11 compared to the case in which materials other than carbonized biomass 10 are mixed into the first layer 11.

[0023] Furthermore, in step S5 for forming the first layer 11, the first layer 11 may be formed by including carbonized biomass 10 and gravel 22. That is, in step S5 for forming the first layer 11, the first layer 11 may be formed by carbonized biomass 10 and soil or rocks containing soil 21 and gravel 22. In this case, for example, in step S5 for forming the first layer 11, the molded product 31 containing soil 21 and gravel 22 other than carbonized biomass 10 may be used, and the first layer 11 may be formed without including other materials such as soil or rocks that fill the spaces between the molded products 31 in the depressions 1. For example, in step S5, which involves forming the first layer 11, a molded product 31 containing soil 21 and gravel 22 other than the carbonized biomass 10 may be used, and other materials such as soil, earth, and rocks may also be included in addition to the molded product 31 to fill the spaces between the molded products 31 in the depression 1. This allows the depression 1 to be filled even if, for example, the size of the depression 1 in which the first layer 11 is formed is large relative to the amount of carbonized biomass 10 to be stored. Furthermore, according to the carbonized biomass storage method according to some embodiments, depressions 1 in mines, etc., can be repaired by mixing the residual gravel after mining with the carbonized biomass 10 and backfilling the area. Furthermore, by placing the carbonized biomass 10 generated in step S1 into a storage area for the carbonized biomass, for example, by placing the carbonized biomass 10 generated in step S1 into a depression 1, the molding of the molded product 31 in step S3 for molding the carbonized biomass and the formation of the first layer 11 in step S5 for forming the first layer may be carried out simultaneously.

[0024] <Step S7 for forming the third layer> Figure 5A schematically shows the state in which the first layer 11 is covered with a second layer 12 formed of soil 12A or soil 12B, which will be described later. Figure 5B schematically shows the state in which the first layer 11 is covered with a second layer 12 formed of clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G. Figure 6 schematically shows the state in which the third layer 13, which will be described later, is formed, located between the first layer 11 and the second layer 12. In some embodiments of the carbonized biomass storage method, the step S7 for forming the third layer 13 may include forming a third layer 13 which is a layer of soil 13A consisting only of soil 21 located between the first layer 11 and the second layer 12 (described later), as shown in Figure 6, or a layer of soil 13B mainly consisting of soil 21 and gravel 22, i.e., a layer of soil 13B in which the volume of soil is greater than the volume of gravel 22 per unit volume.

[0025] The step S7 for forming the third layer 13 is preferably performed when, in the step S9 for covering with the second layer 12 described later, the second layer 12 is formed on top of the first layer 11 using clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G to cover the first layer 11. By performing the step S7 for forming the third layer 13, the carbon retention rate in the first layer 11 can be maintained at an even higher level for a relatively long period of time. Note that the third layer 13 is not an essential layer in the carbonized biomass storage method according to some embodiments, so the step S7 for forming the third layer 13 may not be provided.

[0026] <Step S9 of covering with the second layer> In the carbonized biomass storage method according to some embodiments, step S9 of covering with the second layer 12 is a step of covering the first layer 11 formed in the depression 1, i.e., underground, with the second layer 12, as shown in Figure 5A or Figure 5B. In step S9 of covering with the second layer 12, as shown in Figure 5A, the second layer 12 may be formed with a thickness of 50 cm or more using soil 12A consisting only of soil 21, or soil 12B mainly consisting of soil 21 and containing gravel 22, i.e., soil 12B in which the volume of soil is greater than the volume of gravel 22 per unit volume, to cover the first layer 11. In the carbonized biomass storage method according to some embodiments, it is desirable that the surface 12a of the second layer 12 is the ground surface and is substantially at the same height as the ground surface 5 of the surrounding land 3 of the depression 1.

[0027] For example, regarding the vertical distribution of microorganisms in soil, there are reports that filamentous fungi, to which saprophytic fungi belong, were not detected at depths greater than 50 cm underground. In other words, it is thought that in the soil layers, at depths greater than 50 cm underground, the surrounding oxygen is used up by the activity of microorganisms present in the soil layer, preventing oxygen from reaching the surface atmosphere and resulting in a low-oxygen state, which kills the saprophytic fungi. Thus, air exchange with the atmosphere is greatly restricted in the soil layers at depths greater than 50 cm underground. Therefore, for example, when a new soil layer is formed, even if saprophytic fungi were present at the time of the soil layer's formation, they are thought to die afterward. Furthermore, as mentioned above, air exchange with the atmosphere is greatly restricted in the soil layers at depths greater than 50 cm underground, so for example, CO2 released by saprophytic fungi... ２ The diffusion of CO2 is restricted, and relatively high CO2 levels prevent the growth of decay fungi. ２ It is believed that this will allow the concentration environment to be maintained.

[0028] Therefore, by covering the first layer 11 containing the carbonized biomass 10 with soil 12A or soil 12B to a thickness of 50 cm or more, and maintaining the first layer 11 in a low-oxygen state, decomposition of the carbonized biomass 10 by decay fungi becomes less likely. According to the carbonized biomass storage method according to several embodiments, by covering the first layer 11 with a second layer 12 to a thickness of 50 cm or more, decomposition of the carbonized biomass 10 in the first layer 11 by decay fungi becomes less likely. As a result, the carbon retention rate in the first layer 11 can be maintained at a relatively high level for a relatively long period of time, and the reliability, i.e., permanence, of the carbonized biomass 10 in the first layer 11 as a carbon credit can be improved.

[0029] According to several embodiments of the carbonized biomass storage method, the first layer 11 and the second layer 12 can be used to backfill depressions 1, etc., and the space above the second layer 12 can be made available for various uses, making effective use of the land on which the second layer 12 is formed. According to several embodiments of the carbonized biomass storage method, by covering the first layer 11 with soil 12A or soil 12B with a thickness of 50 cm or more, a second layer 12 can be formed that can maintain a relatively high carbon retention rate in the first layer 11 for a relatively long period of time.

[0030] According to several embodiments of the carbonized biomass storage method, the second layer 12 can be formed at a relatively low cost, as it only requires laying soil 12A or soil 12B on top of the first layer 11. According to several embodiments of the carbonized biomass storage method, by forming a layer of soil 12A or soil 12B (second layer 12), the space above the soil 12A or soil 12B layer (second layer 12) can be made available for various uses, expanding the uses of the land on which the second layer 12 is formed. According to several embodiments of the carbonized biomass storage method, for example, if the place where the first layer 11 and the second layer 12 are formed is a depression 1 in an abandoned mine, forming a layer of soil 12A or soil 12B (second layer 12) contributes to the restoration of the above-ground ecosystem.

[0031] In step S9, which involves covering with the second layer 12, it is preferable to cover the first layer 11 with soil 12A or soil 12B that is 50 cm or thicker and has a porosity of 0.5 or less. This further restricts air exchange with the atmosphere, allowing the carbon retention rate in the first layer 11 to be maintained at a higher level for a relatively long period of time.

[0032] In step S9, where the second layer 12 is covered, the first layer 11 may be covered with soil 12A or soil 12B to a thickness of 60 cm or more. To make effective use of the soil 12A or soil 12B layer, it is conceivable to plant trees in the second layer 12. If the trees to be planted are shallow-rooted trees, their roots will hardly reach a depth of 60 cm or more underground. If the roots were to reach the carbonized biomass 10 in the first layer 11, there is a risk that the decomposition of the carbonized biomass 10 may be accelerated by bacteria or fungi attached to the roots. According to the carbonized biomass storage method according to several embodiments, since the thickness of the soil 12A or soil 12B in the second layer 12 is 60 cm or more, even if shallow-rooted trees are planted in the second layer 12, the possibility of their roots reaching the first layer 11 is low. Therefore, the possibility that the decomposition of the carbonized biomass 10 will be accelerated by the roots reaching the carbonized biomass 10 in the first layer 11 can be reduced.

[0033] In step S9, which involves covering with the second layer 12, the first layer 11 may be covered with soil 12A or soil 12B to a thickness of 100 cm or more. As mentioned above, planting trees in the second layer 12 is conceivable in order to make effective use of the soil 12A or soil 12B layer. If the trees to be planted are deep-rooted trees, their roots will hardly reach a depth of 100 cm or more underground. Furthermore, it is considered that the roots of plants, including grasses as well as trees, do not reach the ground to a depth of 100 cm or more. According to the carbonized biomass storage method according to several embodiments, since the thickness of the soil 12A or soil 12B in the second layer 12 is 100 cm or more, even if deep-rooted trees are planted in the second layer 12, the possibility of their roots reaching the first layer 11 is low. Therefore, the possibility that the decomposition of the carbonized biomass 10 will be accelerated by the roots reaching the carbonized biomass 10 in the first layer 11 can be reduced.

[0034] In step S9, which involves covering with the second layer 12, as shown in Figure 5B, the second layer 12 may be formed on top of the first layer 11 using clay 12C, concrete 12D, asphalt 12E, brick blocks 12F, or concrete blocks 12G to cover the first layer 11. As mentioned above, in the soil layer, air exchange with the atmosphere is greatly restricted in the ground at depths of 50 cm or more. Therefore, for example, when a new soil layer is formed, even if decay fungi were present at the time of soil layer formation, they are thought to die thereafter. Also, because air exchange with the atmosphere is greatly restricted in the ground at depths of 50 cm or more in the soil layer, for example, CO2 released by decay fungi ２ The diffusion of CO2 is restricted, and relatively high CO2 levels prevent the growth of decay fungi. ２ It is thought that the concentration environment can be maintained. Therefore, by covering the first layer 11 with clay 12C or concrete 12D, which allows less air to penetrate and permeate than soil 12A or soil 12B, instead of soil 12A or soil 12B, the decomposition of carbonized biomass by decay fungi will also be made less likely.

[0035] According to several embodiments of carbonized biomass storage methods, by covering the first layer 11 with a second layer 12 such as clay 12C or concrete 12D, it is possible to relatively easily make it difficult for the carbonized biomass 10 in the first layer 11 to decompose by decay fungi. As a result, the carbon retention rate in the first layer 11 can be maintained at a relatively high level for a relatively long period of time, and the reliability, i.e., permanence, of the carbonized biomass 10 in the first layer 11 as a carbon credit can be improved. According to several embodiments of carbonized biomass storage methods, for example, if the place where the first layer 11 and the second layer 12 are formed is an abandoned mine depression 1, the depression 1 can be backfilled with the first layer 11 and the second layer 12, and the space above the second layer 12 can be made available for various uses, making effective use of the land on which the second layer 12 is formed.

[0036] Furthermore, as described above, in step S9 of covering with the second layer 12, if the second layer 12 is formed on top of the first layer 11 using clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G, a third layer 13 may be formed between the first layer 11 and the second layer 12.

[0037] In step S9, which involves covering with the second layer 12, if the second layer 12 is formed on top of the first layer 11 using clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G to cover the first layer 11, the second layer 12 may be formed on top of the first layer 11 with a thickness of 50 cm or less to cover the first layer 11. That is, if the second layer 12 is formed on top of the first layer 11 using clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G to cover the first layer 11, the thickness of the second layer 12 may be thinner compared to the case where the first layer 11 is covered with soil 12A or soil 12B.

[0038] This reduces the amount of the second layer 12 used and makes it relatively difficult for the carbonized biomass of the first layer to be decomposed by decay fungi. As a result, the carbon retention rate in the first layer 11 can be maintained at a relatively high level for a relatively long period of time, improving the reliability, i.e., permanence, of the carbonized biomass 10 in the first layer 11 as a carbon credit. According to the carbonized biomass storage method according to some embodiments, for example, if the place where the first layer 11 and the second layer 12 are formed is an abandoned mine depression 1, the depression 1 can be backfilled with the first layer 11 and the second layer 12, making the space above the second layer 12 usable for various purposes, and the land on which the second layer 12 is formed can be effectively utilized.

[0039] <Step S11 of Monitoring Carbonized Biomass> In the method for storing carbonized biomass according to some embodiments, the step S11 of monitoring the carbonized biomass 10 is a step for monitoring the state of the carbonized biomass 10 during storage. In the step S11 of monitoring the carbonized biomass 10, the state of the carbonized biomass 10 during storage is monitored as follows. Fig. 7 is a diagram showing an embodiment of measuring the oxygen concentration of the first layer 11. Fig. 8 is a diagram showing an embodiment of measuring the CO ２ concentration of the first layer 11. Fig. 9 is a diagram showing an embodiment of measuring the CO ２ concentration of the second layer 12. Fig. 10 is a diagram showing an embodiment of measuring the temperatures of the first layer 11 and the second layer 12. Fig. 11 is a diagram showing an embodiment of measuring the temperature of the first layer 11 and the temperature around the first layer 11.

[0040] In the example shown in Fig. 7 in the method for storing carbonized biomass according to some embodiments, the step S11 of monitoring the carbonized biomass 10 includes a step S111 of measuring the oxygen concentration of the first layer 11. The step S111 of measuring the oxygen concentration of the first layer 11 is a step of measuring the oxygen concentration C1 Ｏ２ of the first layer 11 by an oxygen concentration sensor 51 for measuring the oxygen concentration of the first layer 11. In the method for storing carbonized biomass according to some embodiments, the information on the oxygen concentration C1 Ｏ２ of the first layer 11 measured by the oxygen concentration sensor 51 is transmitted to a monitoring device (not shown) for monitoring the carbonized biomass 10 to be stored, which is managed by an individual or a corporation managing the carbonized biomass 10, via a transmission device 60 and a public communication line network (not shown) such as a mobile phone network or satellite communication.

[0041] At the start point of storing the carbonized biomass 10, for example, oxygen and decay fungi exist in the voids of the carbonized biomass 10. Therefore, at the initial stage after the start of storing the carbonized biomass 10, the decay fungi utilize oxygen and decompose lignin into CO ２ Due to the oxygen consumption by the decay fungi and the chemical and physical adsorption of oxygen to the carbonized biomass, the oxygen concentration C1 Ｏ２ ​​As the oxygen concentration decreases, the decay fungi die, and the decomposition of the carbonized biomass 10 by the decay fungi stops. According to the carbonized biomass storage method according to several embodiments, the oxygen concentration C1 of the first layer 11 Ｏ２ By measuring the oxygen concentration C1 of the first layer 11, Ｏ２ Since the change over time can be observed, the oxygen concentration C1 of the first layer 11 as described above can be confirmed. Ｏ２ The death of decay fungi due to the decrease in [unclear] can be confirmed.

[0042] In some embodiments of the carbonized biomass storage method, step S11, which involves monitoring the carbonized biomass 10, includes step S112, which involves calculating a first residual coefficient. Step S112 involves calculating the oxygen concentration C1 of the first layer 11 measured in step S111, which is calculated from the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10. Ｏ２ This process involves calculating the first residual coefficient Rc1 by dividing the value obtained by subtracting the amount of carbon reduction Q1 calculated based on (Q0 - Q1) by the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10 ((Q0 - Q1) / Q0). The first residual coefficient Rc1 is given by the following equation (1): Rc1 = ((Q0 - Q1) / Q0) ... (1)

[0043] Furthermore, the first residual coefficient Rc1 is the oxygen concentration C1 of the first layer 11, which is determined when the decomposition of lignin stops due to the death of decay fungi. Ｏ２ The oxygen concentration C1 after the equilibrium state is reached. Ｏ２ The calculation will be based on [the specified formula / method].

[0044] According to several embodiments of carbonized biomass storage methods, for example, the oxygen concentration C1 of the first layer 11 in a certain storage location Ｏ２ If the first residual coefficient Rc1 is calculated based on the measurement results, the amount of carbon credits Qc remaining at other storage locations can be calculated using this first residual coefficient Rc1, making it easy to estimate the amount of carbon credits Qc at those other storage locations. The amount of remaining carbon credits Qc is given by the following equation (2): Qc = (Q0 * (Q0 - Q1) / Q0) × 44 / 12 ... (2)

[0045] In a storage method for carbonized biomass according to several embodiments, in the example shown in Figure 8, step S11 of monitoring the carbonized biomass 10 is performed, and the CO of the first layer 11 ２ The process includes step S113 for measuring the concentration of the CO in the first layer 11. ２ Step S113, which measures the concentration, involves measuring the CO of the first layer 11. ２ Concentration C2 ＣＯ２ CO2 for measuring ２ The concentration sensor 52 detects the CO2 in the first layer 11. ２ Concentration C2 ＣＯ２ This is a step in measuring CO2. In some embodiments of carbonized biomass storage methods, ２ CO2 in the first layer 11 as measured by the concentration sensor 52 ２ Concentration C2 ＣＯ２ The information is the oxygen concentration C1 of the first layer 11, measured by the oxygen concentration sensor 51. Ｏ２ Similar to the case of the information mentioned above, the information is transmitted via the transmission device 60 and a public communication network (not shown) such as a mobile phone network or satellite communication to a monitoring device (not shown) managed by an individual or legal entity managing the carbonized biomass 10, for monitoring the stored carbonized biomass 10.

[0046] As mentioned above, at the start of storage of carbonized biomass 10, for example, oxygen and decay fungi are present in the voids of the carbonized biomass 10. Therefore, in the initial stages after the start of storage of carbonized biomass 10, decay fungi utilize oxygen to convert lignin into CO2. ２ It decomposes into CO2 by chemical and physical adsorption of oxygen onto carbonized biomass 10. ２ These are generated. As a result, the oxygen concentration decreases and CO ２ As the concentration increases, the decay fungi die, and the decomposition of the carbonized biomass 10 by the decay fungi stops. According to the carbonized biomass storage method according to several embodiments, the CO of the first layer 11 ２ Concentration C2 ＣＯ２ By measuring the CO of the first layer 11, ２ Concentration C2 ＣＯ２ Since the changes over time can be observed, it is possible to confirm the death of decay fungi through the process described above.

[0047] In some embodiments of the carbonized biomass storage method, step S11, which involves monitoring the carbonized biomass 10, includes step S114, which involves calculating a second residual coefficient. Step S114, which involves calculating the second residual coefficient, involves calculating the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10 from the amount of CO2 in the first layer 11. ２ CO2 in the first layer 11 measured in step S113 for measuring concentration ２ Concentration C2 ＣＯ２ This process involves calculating the second residual coefficient Rc2 by dividing the value obtained by subtracting the amount of carbon reduction Q2 calculated based on (Q0 - Q2) by the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10 ((Q0 - Q2) / Q0). The second residual coefficient Rc2 is given by the following equation (3): Rc2 = ((Q0 - Q2) / Q0) ... (3)

[0048] Furthermore, the second residual coefficient Rc2 is determined by the cessation of lignin decomposition due to the death of decay fungi, and the CO of the first layer 11. ２ Concentration C2 ＣＯ２ CO after it reaches equilibrium ２ Concentration C2 ＣＯ２ The calculation will be based on [the specified formula / method].

[0049] According to several embodiments of carbonized biomass storage methods, for example, the CO2 concentration C2 of the first layer 11 in a certain storage location ＣＯ２ If the second residual coefficient Rc2 is calculated based on the measurement results, the amount of carbon credits Qc remaining at other storage locations can be calculated using this second residual coefficient Rc2, making it easy to estimate the amount of carbon credits Qc at those other storage locations. The amount of remaining carbon credits Qc is given by the following equation (4): Qc = (Q0 * (Q0 - Q2) / Q0) × 44 / 12 ... (4)

[0050] In a carbonized biomass storage method according to several embodiments, in the example shown in Figure 9, step S11 of monitoring the carbonized biomass 10 is performed by monitoring the CO2 in the second layer 12. ２ The process includes step S115 for measuring the concentration of CO in the second layer 12. ２ Step S115, which measures the concentration, involves the CO2 in the second layer 12. ２ CO2 for measuring concentration２ The CO2 concentration sensor 53 detects CO2 in the second layer 12. ２ Concentration C2 ＣＯ２ This is a step in measuring CO2. In some embodiments of carbonized biomass storage methods, ２ CO2 in the second layer 12 as measured by the concentration sensor 53 ２ Concentration C2 ＣＯ２ The information is the oxygen concentration C1 of the first layer 11, measured by the oxygen concentration sensor 51. Ｏ２ Similar to the case of the information mentioned above, the information is transmitted via the transmission device 60 and a public communication network (not shown) such as a mobile phone network or satellite communication to a monitoring device (not shown) managed by an individual or legal entity managing the carbonized biomass 10, for monitoring the stored carbonized biomass 10.

[0051] As a result, the CO2 in the second layer 12 ２ Concentration C2 ＣＯ２ Based on this, it is possible to detect when decay or oxidation of the carbonized biomass 10 in the first layer 11 has progressed due to some cause.

[0052] In a method for storing carbonized biomass according to several embodiments, in the example shown in Figure 10, the step S11 for monitoring the carbonized biomass 10 includes a step S116 for measuring the temperature of the first layer and a step S117 for measuring the temperature of at least the second layer. The step S116 for measuring the temperature of the first layer is a step of measuring the temperature T1 of the first layer 11 using a temperature sensor 54 for measuring the temperature T1 of the first layer 11. The step S117 for measuring at least the temperature of the second layer is a step of measuring the temperature of at least the second layer 12 by using at least a temperature sensor 55 for measuring the temperature T2 of the second layer 12. In the example shown in Figure 10, the step S117 for measuring at least the temperature of the second layer measures the temperature T2 of the second layer 12 using a temperature sensor 55 for measuring the temperature T2 of the second layer 12. A plurality of pairs of the temperature sensors 54 and 55 are provided, and it is preferable that they be spaced apart from each other along the interface near the interface between the first layer 11 and the second layer 12.

[0053] In some embodiment of the carbonized biomass storage method, the information on the temperature T1 of the first layer 11 measured by the temperature sensor 54 and the information on the temperature T2 of the second layer 12 measured by the temperature sensor 55 are used to determine the oxygen concentration C1 of the first layer 11 measured by the oxygen concentration sensor 51. Ｏ２ Similar to the case of the information mentioned above, the information is transmitted via the transmission device 60 and a public communication network (not shown) such as a mobile phone network or satellite communication to a monitoring device (not shown) managed by an individual or legal entity managing the carbonized biomass 10, for monitoring the stored carbonized biomass 10.

[0054] When the carbonized biomass 10 in the first layer 11 decays or oxidizes for some reason, the temperature T1 of the first layer 11 rises. However, the temperature T1 of the first layer 11 is also affected by the temperature of the ground surface, i.e., the surface 12a of the second layer 12. Therefore, it is difficult to determine whether the decay or oxidation of the carbonized biomass 10 has progressed or whether it is due to the influence of the ground surface temperature 5 based solely on the rise in the temperature T1 of the first layer 11. According to some embodiments of carbonized biomass storage methods, the temperature T2 of the second layer 12, which is closer to the ground surface 5 than the first layer 11, is measured and compared with the temperature T1 of the first layer 11. This allows the direction of heat flow to be determined, and thus it is possible to estimate whether or not the decay or oxidation of the carbonized biomass 10 in the first layer 11 has progressed. Furthermore, according to the carbonized biomass storage method according to several embodiments, the calorific value of the carbonized biomass 10 in the first layer 11 can be estimated from the temperature T1 of the first layer 11 and the difference between the temperature T1 of the first layer 11 and the temperature T2 of the second layer 12, so it is possible to monitor whether or not the carbonized biomass 10 is being stored stably in a low-oxygen state in the first layer 11.

[0055] In some embodiments of the method for storing carbonized biomass, the step S117 for measuring the temperature of at least the second layer may include at least one of the following steps: the step S118 for measuring the temperature of the second layer, the step S119 for measuring the temperature of the layer directly below the first layer 11, or the step S121 for measuring the temperature of a layer adjacent to the first layer 11 at the same height as the first layer 11. In the example shown in Figure 11, the step S117 for measuring the temperature of at least the second layer includes the step S118 for measuring the temperature of the second layer, the step S119 for measuring the temperature of the layer directly below the first layer 11, and the step S121 for measuring the temperature of a layer adjacent to the first layer 11 at the same height as the first layer 11.

[0056] In the example shown in Figure 11, in addition to the temperature sensor 54 for measuring the temperature T1 of the first layer 11 and the temperature sensor 55 for measuring the temperature T2 of the second layer 12 described above, there is also a temperature sensor 56 for measuring the temperature of the layer directly below the first layer 11, a temperature sensor 57 positioned relatively close to the temperature sensor 56 for measuring the temperature T1 of the first layer 11, a temperature sensor 58 for measuring the temperature of the layer adjacent to the first layer 11 at the same height as the first layer 11, and a temperature sensor 59 positioned relatively close to the temperature sensor 58 for measuring the temperature T1 of the first layer 11.

[0057] Furthermore, multiple pairs of the temperature sensors 56 and 57 are provided, and it is preferable that they be spaced apart from each other near the interface between the first layer 11 and the layer directly below it, that is, along the bottom surface of the depression 1. Multiple pairs of the temperature sensors 58 and 59 are provided, and it is preferable that they be spaced apart from each other in the circumferential direction near the periphery of the first layer 11. Also, in the example shown in Figure 11, the temperature sensor 54 for measuring the temperature T1 of the first layer 11 and the temperature sensor 55 for measuring the temperature T2 of the second layer 12 are placed relatively close together. Multiple pairs of the temperature sensors 54 and 55 are provided, and it is preferable that they be spaced apart from each other along the interface near the interface between the first layer 11 and the second layer 12.

[0058] In some embodiment of the carbonized biomass storage method, the temperature information measured by each of these temperature sensors 56-59 is used to determine the oxygen concentration C1 of the first layer 11 measured by the oxygen concentration sensor 51. Ｏ２ Similar to the case of the information mentioned above, the information is transmitted via the transmission device 60 and a public communication network (not shown) such as a mobile phone network or satellite communication to a monitoring device (not shown) managed by an individual or legal entity managing the carbonized biomass 10, for monitoring the stored carbonized biomass 10.

[0059] In the example shown in Figure 11, by comparing the temperatures measured by two paired temperature sensors, the direction of heat flow on the top, bottom, and sides of the first layer 11 can be determined, thereby improving the accuracy of estimating whether or not decay or oxidation has progressed in the carbonized biomass 10 of the first layer 11. Furthermore, according to the example shown in Figure 11, the accuracy of estimating the calorific value of the carbonized biomass 10 of the first layer 11 can be improved.

[0060] Furthermore, by using sampling methods such as boring, it is possible to collect samples of the carbonized biomass 10 from the first layer 11 down to the surface 5 by penetrating the second layer 12 from the surface 5, and to estimate whether or not the carbonized biomass 10 has decayed or oxidized using an inspection device installed at the surface 5. For example, by measuring the amount of carbon contained in the carbonized biomass 10 sampled from the first layer 11, the amount of carbon credits Qc can be estimated. By examining the amount and presence or absence of decay fungi present in the sampled carbonized biomass 10, it is possible to predict the current state of the carbonized biomass 10 and its future decay progression.

[0061] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0062] The contents of each embodiment described above can be understood, for example, as follows: (1) A method for storing carbonized biomass according to at least one embodiment of the present disclosure comprises the steps of: forming a first layer 11 containing carbonized biomass 10 in the ground (S5), and covering the first layer 11 formed in the ground with a second layer 12 having a thickness of 50 cm or more (step S9 of covering with a second layer). In the step of covering with a second layer (step S9 of covering with a second layer), the first layer 11 is covered by forming a second layer 12 with soil 12A consisting only of soil 21, or soil 12B mainly consisting of soil 21 and gravel 22, with a thickness of 50 cm or more.

[0063] According to the method described in (1) above, covering the first layer 11 with a second layer 12 with a thickness of 50 cm or more makes it difficult for decay fungi to decompose the carbonized biomass 10 in the first layer 11. This allows the carbon retention rate in the first layer 11 to be maintained at a relatively high level for a relatively long period of time, improving the reliability, i.e., permanence, of the carbonized biomass 10 in the first layer 11 as a carbon credit. According to the method described in (1) above, for example, if the place where the first layer 11 and the second layer 12 are formed is a depression 1 in an abandoned mine, the depression 1 can be backfilled with the first layer 11 and the second layer 12, making the space above the second layer 12 usable for various purposes, and allowing the land on which the second layer 12 is formed to be effectively utilized. According to the method described in (1) above, by covering the first layer 11 with soil (soil 12A or soil 12B) with a thickness of 50 cm or more, a second layer 12 can be formed that can maintain a relatively high carbon retention rate in the first layer 11 for a relatively long period of time, and this can be done relatively easily. According to the method described in (1) above, the second layer 12 can be formed at a relatively low cost, as it only requires laying soil (soil 12A or soil 12B) on top of the first layer 11. According to the method described in (1) above, by forming a layer of soil (soil 12A or soil 12B), the space above the soil (soil 12A or soil 12B) layer can be made available for various uses, expanding the range of uses for the land on which the second layer 12 is formed. According to the method described in (1) above, for example, if the place where the first layer 11 and the second layer 12 are formed is a depression 1 in an abandoned mine, forming a layer of soil (soil 12A or soil 12B) contributes to the restoration of the above-ground ecosystem.

[0064] (2) In some embodiments, in the method of (1) above, in the step of covering with a second layer (step S9 of covering with a second layer), the first layer 11 may be covered with soil (soil 12A or soil 12B) that is 50 cm or thicker and has a void ratio of 0.5 or less.

[0065] According to the method described in (2) above, by making the porosity of the soil (soil 12A or soil 12B) 0.5 or less, the exchange of air with the atmosphere is further restricted, so that the carbon retention rate in the first layer 11 can be maintained at a higher level for a relatively long period of time.

[0066] (3) In some embodiments, in the method of (1) or (2) described above, in the step of covering with a second layer (step S9 of covering with a second layer), the first layer may be covered with soil to a thickness of 60 cm or more.

[0067] According to the method described in (3) above, since the thickness of the soil layer (soil 12A or soil 12B) of the second layer 12 is 60 cm or more, even if shallow-rooted trees are planted in the second layer 12, the possibility of their roots reaching the first layer is low. Therefore, the possibility that the decomposition of the carbonized biomass 10 will be accelerated by the roots reaching the carbonized biomass 10 in the first layer 11 can be reduced.

[0068] (4) In some embodiments, in the method of (1) or (2) described above, in the step of covering with a second layer (step S9 of covering with a second layer), the first layer 11 may be covered with soil (soil 12A or soil 12B) to a thickness of 100 cm or more.

[0069] According to the method described in (4) above, since the thickness of the soil layer (soil 12A or soil 12B) of the second layer 12 is 100 cm or more, even if deep-rooted trees are planted in the second layer 12, the possibility of their roots reaching the first layer 11 is low. Therefore, the possibility that the decomposition of the carbonized biomass 10 will be accelerated by the roots reaching the carbonized biomass 10 in the first layer 11 can be reduced.

[0070] (5) A method for storing carbonized biomass according to at least one embodiment of the present disclosure comprises the steps of: forming a first layer containing carbonized biomass in the ground (S5), and covering the first layer 11 formed in the ground with a second layer (S9). In the step of covering with a second layer (S9), the second layer 12 is formed on top of the first layer 11 using clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G to cover the first layer 11.

[0071] According to the method described in (5) above, by covering the first layer 11 with a second layer 12 such as clay 12C or concrete 12D, it is possible to relatively easily make it difficult for the carbonized biomass 10 in the first layer 11 to decompose by decay fungi. As a result, the carbon retention rate in the first layer 11 can be maintained at a relatively high level for a relatively long period of time, and the reliability, i.e., permanence, of the carbonized biomass 10 in the first layer 11 as a carbon credit can be improved. According to the method described in (5) above, for example, if the place where the first layer 11 and the second layer 12 are formed is a depression 1 in an abandoned mine, the depression 1 can be backfilled with the first layer 11 and the second layer 12, and the space above the second layer 12 can be made available for various uses, making effective use of the land on which the second layer 12 is formed.

[0072] (6) In some embodiments, in the method of (5) described above, in the step of covering with a second layer (step S9 of covering with a second layer), a second layer 12 having a thickness of 50 cm or less is formed on top of the first layer 11 to cover the first layer 11.

[0073] According to the method described in (6) above, the amount of the second layer 12 used can be reduced, and the decomposition of the carbonized biomass 10 in the first layer 11 by decay fungi can be made relatively difficult. As a result, the carbon retention rate in the first layer 11 can be maintained at a relatively high level for a relatively long period of time, and the reliability, i.e., permanence, of the carbonized biomass 10 in the first layer 11 as a carbon credit can be improved. According to the method described in (6) above, for example, if the place where the first layer 11 and the second layer 12 are formed is an abandoned mine depression 1, the depression 1 can be backfilled with the first layer 11 and the second layer 12, and the space above the second layer 12 can be made available for various uses, making effective use of the land on which the second layer 12 is formed.

[0074] (7) In some embodiments, the method of (5) or (6) above may include a step of forming a third layer 13 which is a layer of soil 13A consisting only of soil 21, or a layer of soil 13B mainly consisting of soil 21 and gravel 22 (step S7 of forming the third layer). In the step of covering with the second layer (step S9 of covering with the second layer), the second layer 12 may be formed on top of the third layer 13 using any of clay 12C, concrete 12D, asphalt 12E, brick block 12F, or concrete block 12G to cover the first layer 11.

[0075] According to the method described in (7) above, the carbon retention rate in the first layer 11 can be maintained at an even higher level for a relatively long period of time.

[0076] (8) In some embodiments, in any of the methods (1) to (7) above, the first layer 11 may be formed by carbonized biomass 10 in step S5 of forming the first layer.

[0077] According to the method described in (8) above, the amount of carbon credits per unit volume in the first layer 11 can be made relatively larger compared to the case in which something other than carbonized biomass 10 is mixed into the first layer 11.

[0078] (9) In some embodiments, in any of the methods (1) to (7) above, the first layer S5 may be formed by forming a first layer 11 containing carbonized biomass 10 and gravel 22.

[0079] According to the method described in (9) above, even if the size of the depressions 1 etc. that form the first layer 11 is large relative to the amount of carbonized biomass 10 to be stored, the depressions 1 etc. can be filled in. Furthermore, according to the method described in (9) above, for example, depressions 1 in mines, etc. can be repaired by mixing the residual gravel after mining with the carbonized biomass 10 and backfilling the area.

[0080] (10) In some embodiments, the method of (1) to (9) above may include a step S3 of carbonizing woody biomass at a temperature of 290°C or more and less than 400°C to produce carbonized biomass.

[0081] At carbonization temperatures of around 300°C, cellulose and hemicellulose in woody biomass are decomposed and carbonized, but lignin remains largely undecomposed and uncarbonized. According to method (10) above, the carbonization of lignin in woody biomass can be minimized to ensure sufficient residual carbon, while simultaneously decomposing and carbonizing cellulose and hemicellulose. This suppresses decay by brown rot and soft rot fungi, improving the reliability, i.e., permanence, of the carbonized biomass 10 as a carbon credit. Furthermore, lignin acts as an adhesive component, making it easier for woody biomass to coalesce when compacted. According to method (10) above, a relatively large amount of lignin can be retained, making it easier for the carbonized biomass 10 to coalesce when compacted, facilitating handling during storage and reducing the storage space required. Moreover, compaction of the carbonized biomass 10 reduces voids, thus preventing the invasion of decay fungi and reducing CO2 adsorption through chemical and physical adsorption of oxygen. ２ This can suppress the occurrence of [unclear]. However, when the carbonization temperature of the carbonized biomass 10 reaches around 400°C, the risk of spontaneous combustion of the carbonized biomass 10 increases. According to the method described in (10) above, the risk of spontaneous combustion can be reduced by keeping the carbonization temperature below 400°C.

[0082] (11) In some embodiments, the method of (1) to (10) above may include a step S111 of measuring the oxygen concentration of the first layer.

[0083] According to the method described in (11) above, the oxygen concentration C1 of the first layer 11 Ｏ２ By measuring the oxygen concentration C1 of the first layer 11, Ｏ２ Since the change over time can be observed, the oxygen concentration C1 as described above Ｏ２ The death of decay fungi due to the decrease in [unclear] can be confirmed.

[0084] (12) In some embodiments, in the method of (11) above, the oxygen concentration C1 of the first layer 11 measured in step S111 is determined from the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10. Ｏ２ The system may also include a step S112 in which the first residual coefficient Rc1 is calculated by dividing the value obtained by subtracting the amount of carbon reduction Q1 calculated based on (Q0 - Q1) by the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10 ((Q0 - Q1) / Q0).

[0085] According to the method described in (12) above, for example, the oxygen concentration C1 of the first layer 11 in a certain storage location Ｏ２ If a first residual coefficient Rc1 is calculated based on the measurement results, the amount of carbon credits Qc remaining at other storage locations can be calculated using this first residual coefficient Rc1, making it easy to estimate the amount of carbon credits Qc at those other storage locations.

[0086] (13) In some embodiments, in any of the methods (1) to (12) above, the CO of the first layer 11 ２ Concentration C2 ＣＯ２ The process may include step S113, which involves measuring [something].

[0087] According to the method described in (13) above, the CO of the first layer 11 ２ Concentration C2 ＣＯ２ By measuring the CO of the first layer 11, ２ Concentration C2 ＣＯ２ Since the changes over time can be observed, it is possible to confirm the death of decay fungi through the process described above.

[0088] (14) In some embodiments, in the method of (13) above, the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10 is used to determine the CO2 of the first layer ２ Concentration C2ＣＯ２ CO of the first layer 11 measured in step S113 ２ Concentration C2 ＣＯ２ The system may also include a step S114 in which the second residual coefficient Rc2 is calculated by dividing the value obtained by subtracting the amount of carbon reduction Q2 calculated based on (Q0 - Q2) by the amount of carbon Q0 contained in the carbonized biomass 10 at the start of storage of the carbonized biomass 10 ((Q0 - Q2) / Q0).

[0089] According to the method described in (14) above, for example, the CO2 concentration C2 of the first layer 11 in a certain storage location ＣＯ２ If a second residual coefficient Rc2 is calculated based on the measurement results, the amount of carbon credits Qc remaining at other storage locations can be calculated using this second residual coefficient Rc2, making it easy to estimate the amount of carbon credits Qc at those other storage locations.

[0090] (15) In some embodiments, in any of the methods described in (1) to (14) above, the CO of the second layer 12 ２ Concentration C2 ＣＯ２ The process may include step S115, which involves measuring [something].

[0091] According to the method described in (15) above, the CO of the second layer 12 ２ Based on the concentration, it is possible to detect that decay or oxidation has progressed in the carbonized biomass 10 of the first layer 11 due to some cause.

[0092] (16) In some embodiments, any of the methods (1) to (15) above may include a step S116 of measuring the temperature of the first layer 11 and a step S117 of measuring the temperature of at least the second layer 12.

[0093] When the carbonized biomass in the first layer 11 decays or oxidizes for some reason, the temperature T1 of the first layer 11 rises. However, the temperature T1 of the first layer 11 is also affected by the temperature of the ground surface (the surface 12a of the second layer 12). Therefore, it is difficult to determine from the temperature rise of the first layer 11 alone whether the decay or oxidation of the carbonized biomass 10 has progressed or whether it is due to the influence of the ground surface temperature. According to the method described in (16) above, by measuring the temperature T2 of the second layer 12, which is closer to the ground surface than the first layer 11, and comparing it with the temperature T1 of the first layer 11, the direction of heat flow can be determined, and it is possible to estimate whether or not the decay or oxidation of the carbonized biomass 10 in the first layer 11 has progressed. Furthermore, according to the method described in (16) above, the calorific value of the carbonized biomass 10 in the first layer 11 can be estimated from the temperature T1 of the first layer 11 and the difference between the temperature T1 of the first layer 11 and the temperature T2 of the second layer 12, so it is possible to monitor whether or not the carbonized biomass 10 is being stored stably in a low-oxygen state in the first layer 11.

[0094] (17) In some embodiments, the step S117 of measuring the temperature of at least the second layer 12 in the method of (16) above may include at least one of the steps of measuring the temperature of the second layer 12 in step S118 and measuring the temperature of the layer directly below the first layer 11 in step S119, or measuring the temperature of a layer adjacent to the first layer 11 at the same height as the first layer 11 in step S121.

[0095] According to the method described in (17) above, the accuracy of estimating whether or not decay or oxidation has progressed in the carbonized biomass 10 of the first layer 11 can be improved. Furthermore, according to the method described in (17) above, the accuracy of estimating the calorific value of the carbonized biomass 10 of the first layer 11 can be improved.

[0096] (18) In some embodiments, the method of (1) to (17) above may include a step S3 of forming carbonized biomass 10 into a layered or block-shaped molded product 31 having a minimum dimension of 1 m or more. In the step S5 of forming the first layer 11, the first layer 11 may be formed including the molded product 31 formed in the step S3 of forming the carbonized biomass 10.

[0097] According to the method described in (18) above, the size of the molded product 31 becomes relatively large, so the surface area per unit volume of the molded product 31 can be made relatively small. As a result, the penetration of oxygen from the surface of the molded product 31 can be relatively reduced, thereby suppressing decay and oxidation.

[0098] (19) In some embodiments, in the method of (18) above, in step S3 for molding the carbonized biomass 10, a mixture of at least one of soil 21 or gravel 22 and the carbonized biomass 10 may be molded as a molded product 31.

[0099] According to the method described in (19) above, even if the size of the depressions 1 etc. that form the first layer 11 is large relative to the amount of carbonized biomass 10 to be stored, the amount of molded product 31 can be increased by mixing at least one of soil 21 or gravel 22 with the molded product 31, thereby filling the depressions 1 etc. Furthermore, according to the method described in (19) above, residual gravel can be processed by mixing residual gravel after mining in a mine, for example, with carbonized biomass 10 and forming the molded product 31.

[0100] 1. Depression 3. Earth 5. Surface 10. Carbonized Biomass 11. First Layer 12. Second Layer 12a. Surface 12A. Soil 13B. Soil 12C. Clay 12D. Concrete 12E. Asphalt 12F. Brick Block 12G. Concrete Block 13. Third Layer 13A. Soil 13B. Soil 21. Soil 22. Gravel 51. Oxygen Concentration Sensor 52. CO ２ Concentration sensor 53 CO ２ Concentration sensor 54 Temperature sensor 55 Temperature sensor 56 Temperature sensor 57 Temperature sensor 58 Temperature sensor 59 Temperature sensor 60 Transmission device

Claims

1. A method for storing carbonized biomass, comprising the steps of: forming a first layer containing carbonized biomass underground; and covering the first layer formed underground with a second layer with a thickness of 50 cm or more, wherein in the step of covering with the second layer, the second layer is formed on top of the first layer with soil consisting only of soil, or soil mainly containing gravel, with a thickness of 50 cm or more, thereby covering the first layer.

2. The method for storing carbonized biomass according to claim 1, wherein in the step of covering with the second layer, the first layer is covered with soil that is 50 cm or thick and has a void ratio of 0.5 or less.

3. The method for storing carbonized biomass according to claim 1 or 2, wherein in the step of covering with the second layer, the first layer is covered with soil to a thickness of 60 cm or more.

4. The method for storing carbonized biomass according to claim 1 or 2, wherein in the step of covering with the second layer, the first layer is covered with soil to a thickness of 100 cm or more.

5. A method for storing carbonized biomass, comprising the steps of: forming a first layer containing carbonized biomass underground; and covering the first layer formed underground with a second layer, wherein in the step of covering with the second layer, the second layer is formed on top of the first layer using clay, concrete, asphalt, brick blocks, or concrete blocks to cover the first layer.

6. The method for storing carbonized biomass according to claim 5, wherein in the step of covering with the second layer, the second layer having a thickness of 50 cm or less is formed on top of the first layer to cover the first layer.

7. A method for storing carbonized biomass according to claim 5 or 6, comprising the step of forming a third layer which is a soil layer consisting only of soil or a soil layer mainly consisting of soil and gravel, located between the first layer and the second layer, wherein in the step of covering with the second layer, the second layer is formed on top of the third layer using any of clay, concrete, asphalt, brick blocks, or concrete blocks to cover the first layer.

8. The method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, wherein the step of forming the first layer is to form the first layer with carbonized biomass.

9. The method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, wherein the step of forming the first layer comprises carbonized biomass and gravel.

10. A method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, comprising the step of carbonizing woody biomass at a temperature of 290°C or higher and less than 400°C to produce the carbonized biomass.

11. A method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, comprising the step of measuring the oxygen concentration of the first layer.

12. A method for storing carbonized biomass according to claim 11, comprising the step of calculating a first residual coefficient by dividing the value obtained by subtracting the amount of carbon reduction Q1 calculated based on the oxygen concentration of the first layer measured in the step of measuring the oxygen concentration of the first layer from the amount of carbon Q0 contained in the carbonized biomass at the start of storage of the carbonized biomass (Q0 - Q1 / Q0) by the amount of carbon Q0 contained in the carbonized biomass at the start of storage of the carbonized biomass.

13. CO2 in the first layer ２ A method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, comprising the step of measuring the concentration.

14. At the start of storage of the carbonized biomass, the amount of carbon Q0 contained in the carbonized biomass is calculated from the CO of the first layer. ２ CO2 from the first layer measured in the concentration measurement step ２ A method for storing carbonized biomass according to claim 13, comprising the step of calculating a second residual coefficient by dividing the value obtained by subtracting the amount of carbon reduction Q2 calculated based on the concentration (Q0 - Q2) by the amount of carbon Q0 contained in the carbonized biomass at the start of storage of the carbonized biomass ((Q0 - Q2) / Q0).

15. CO2 in the second layer ２ A method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, comprising the step of measuring the concentration.

16. A method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, comprising the steps of: measuring the temperature of the first layer; and measuring the temperature of at least the second layer.

17. The method for storing carbonized biomass according to claim 16, wherein the step of measuring the temperature of at least the second layer comprises at least one of the following steps: measuring the temperature of the second layer and measuring the temperature of the layer directly below the first layer, or measuring the temperature of a layer adjacent to the first layer at the same height as the first layer.

18. A method for storing carbonized biomass according to any one of claims 1, 2, 5, or 6, comprising the step of forming carbonized biomass into a layered or lump-shaped molded product having a minimum dimension of 1 m or more, wherein the step of forming the first layer includes the molded product formed in the step of forming the carbonized biomass.

19. The method for storing carbonized biomass according to claim 18, wherein in the step of forming the carbonized biomass, a mixture of at least one of soil or gravel and the carbonized biomass is formed as the molded product.

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