Method for producing granules

Abstract

To provide a technique capable of efficiently producing a recycled material having a high carbon ratio.SOLUTION: A manufacturing method for a granular material according to the present invention includes a heating and stirring step of generating a granular material by stirring a processing target object including waste while heating the processing target object in an accommodation portion that is an internal space of a processing tank, and an accommodation step of accommodating a new processing target object in the accommodation portion after the heating and stirring step. In the heating and stirring step, the accommodation unit is heated to 180 °C or higher and 400 °C or lower by a first heating unit that heats a wall portion of the treatment tank and a second heating unit that supplies a heated gas to the accommodation unit, and the treatment target material is stirred by rotating, in the accommodation unit, a stirring shaft including a shaft portion and a plurality of blade portions provided on an outer circumferential surface of the shaft portion at intervals along a rotation axis. In the housing step, the new processing subject is housed in the housing portion in a state in which at least a portion of the granules remains such that the bulk of the produced granules exceeds at least a portion of the shaft portion.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a waste recycling technology. [Background technology]

[0002] From the viewpoint of reducing greenhouse gas emissions, it is desirable to recycle waste without incineration. Therefore, a technology for producing carbonized material by pyrolyzing waste is known. For example, Patent Document 1 describes a method for producing granular material using waste containing a thermoplastic resin, which includes a stirring step of stirring the material contained in a treatment tank. For example, Patent Document 2 describes a carbonization furnace having a main body for pyrolyzing the waste and an exhaust section for exhausting exhaust gases generated during the pyrolysis of the waste. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-16295 [Patent Document 2] Patent No. 6578500 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to further promote waste recycling, there is a need for technology that can more efficiently produce recycled materials with a high carbon content.

[0005] The present invention relates to a technology that can efficiently produce recycled materials with a high carbon content. [Means for solving the problem]

[0006] A method for producing granular material according to one embodiment of the present invention is a method for producing granular material using waste, comprising the steps of: a heating and stirring step of heating and stirring the material to be treated, including the waste, in a storage section, which is the internal space of the treatment tank, to generate granular material; a storing step of storing a new object to be processed in the storing section after the heating and stirring step; Includes. In the heating and stirring step, The container is heated to 180°C or higher and 400°C or lower by a first heating unit that heats a wall portion of the treatment tank and a second heating unit that supplies heated gas to the container, and The material to be processed is stirred by rotating an agitation shaft in the storage section, the agitation shaft having a shaft portion that can rotate around a rotation axis extending in a direction intersecting the vertical direction and a plurality of blade portions that are spaced along the rotation axis on the outer surface of the shaft portion. In the storing step, the new object to be processed is stored in the storage section, leaving at least a portion of the granular material so that the volume of the generated granular material exceeds at least a portion of the shaft portion. [Effects of the Invention]

[0007] According to the present invention, recycled materials with a high carbon content can be efficiently produced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic view showing a processing apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the treatment tank of the treatment apparatus, showing the cross section of the treatment tank as seen from the front. [Figure 3] FIG. 2 is a schematic cross-sectional view of the treatment tank of the treatment apparatus, showing the cross section of the treatment tank as seen from the side. [Figure 4] 10 is a flowchart showing a method for producing granular materials using the processing device. [Figure 5] FIG. 10 is a schematic diagram showing a processing apparatus according to a modified example of the embodiment. [Figure 6]FIG. 2 is a schematic cross-sectional view showing a treatment tank of the treatment apparatus, showing a cross section of the treatment tank as seen from the front. [Figure 7] FIG. 4 is a schematic diagram illustrating a method for producing granular material according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Outline of an embodiment of the present invention> A method for producing granular materials according to one embodiment of the present invention is characterized in that it generates granular materials by heating a treatment tank using two heating units (described below) while stirring materials to be treated, including waste, and then storing new materials in the treatment tank while leaving a predetermined amount of the generated granular materials in the treatment tank. This improves the efficiency and controllability of heating in the treatment tank, allowing for the efficient production of carbonized materials with a high carbon content. Therefore, the method for producing granular materials according to this embodiment contributes to the promotion of waste recycling and ultimately contributes to the realization of a resource-circulating society.

[0010] In one embodiment of the present invention, "granular" refers to the shape of each fragment of the crushed material to be treated. Furthermore, "granular body" refers to an aggregate of multiple fragments that are separated from each other. By forming a waste-derived product into a granular body, it is possible to make it into a form that is easy to handle as a recycled material. The particle size of the granular body is preferably 10 μm or more, more preferably 30 μm or more, and preferably 5 cm or less, more preferably 1 cm or less, and even more preferably 0.5 cm or less. The particle size of the granular body refers to the maximum diameter of each fragment that constitutes the granular body. The detailed structure of the granular body will be described later.

[0011] The waste used in one embodiment of the present invention includes, for example, general waste generated from households, businesses, etc. From the viewpoint of improving processing efficiency and carbonization efficiency, the waste preferably includes combustible waste. Combustible waste here refers to waste primarily containing organic matter classified as combustible garbage, such as food waste, paper, fabrics, resin products, plants, wood products, rubber products, leather products, and mixtures thereof. Thus, combustible waste may contain cellulose, such as paper, some fabrics, plants, and wood products. The content of combustible waste in the waste is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass, from the viewpoint of improving the carbonization rate of the generated granules.

[0012] Furthermore, the waste used in one embodiment of the present invention is preferably waste containing a thermoplastic resin. Examples of waste containing a thermoplastic resin include used packaging containers (food containers, bottles, etc.), used absorbent articles (disposable diapers, sanitary napkins, etc.), and marine debris. Of these, the waste preferably includes used absorbent articles, which are generated in childcare or nursing care and can be problematic for disposal. The thermoplastic resin contained in the waste is not limited to a specific type, and examples include polyolefin, polyester, polyacrylic acid, and sodium polyacrylate. Furthermore, the waste may contain two or more types of thermoplastic resins.

[0013] The waste used in one embodiment of the present invention also includes, for example, non-infectious waste and infectious waste generated by medical institutions and the like. Examples of waste-generating medical institutions and the like include hospitals, clinics, hygiene testing centers, nursing homes for the elderly, nursing care centers, and midwifery clinics. Infectious waste includes waste containing or potentially contaminating pathogens that can infect humans, waste contaminated with such pathogens, and waste that could potentially infect humans. Specific examples include used absorbent articles used by patients with infectious gastroenteritis and disposable products such as syringes contaminated with blood or body fluids. Non-infectious waste includes waste other than infectious waste (e.g., combustible materials), such as paper and food waste, as well as non-infectious bandages, absorbent cotton, gloves, surgical masks, aprons, commonly used absorbent articles, and other plastic products.

[0014] First Embodiment [Processing device configuration] First, a processing apparatus 100 that can be used in the method for producing granular material according to the first embodiment of the present invention will be described with reference to Figures 1 to 3. The processing apparatus 100 includes a processing tank 101, a first heating unit 110, a second heating unit 120, an exhaust treatment section 130, and a control section 140. The processing apparatus 100 is configured as, for example, a batch-type carbonization apparatus.

[0015] The treatment tank 101 has a wall 101a and a storage section 101b. The storage section 101b can store the object to be treated by the treatment device 100, and is configured as an internal space of the treatment tank 101 surrounded by the wall 101a. Each of Figures 1 to 3 shows the interior of the storage section 101b by showing a vertical cross section of the wall 101a. In the treatment tank 101, a portion of the wall 101a is configured to be openable and closable as an inlet for the object to be treated.

[0016] The treatment tank 101 further includes one or more agitation shafts 102. The agitation shaft 102 includes a shaft portion 102a and multiple blade portions 102b. The shaft portion 102a is configured as a rod-shaped member that can rotate around a rotation axis C extending horizontally to the side. Both ends of the shaft portion 102a are supported by the wall portion 101a on the sides of the storage portion 101b, and the portion between the both ends supported by the wall portion 101a is located within the storage portion 101b. The multiple blade portions 102b are spaced apart along the longitudinal direction. Furthermore, each blade portion 102b protrudes in various radial directions from the outer circumferential surface of the shaft portion 102a.

[0017] From the viewpoint of increasing the efficiency of stirring, it is preferable that the treatment tank 101 has a plurality of stirring shafts 102. These stirring shafts 102 are preferably arranged, for example, along a horizontal direction perpendicular to the vertical direction, with the shaft portions 102a being approximately parallel. In the example shown in Figure 3, the treatment tank 101 has two stirring shafts 102.

[0018] The first heating unit 110 heats the wall 101a of the processing tank 101. That is, the first heating unit 110 has a function of externally heating the storage section 101b. In this embodiment, the first heating unit 110 has a heater 111 that heats the wall 101a. Although the heating method of the heater 111 is not limited, an electric heater is preferable from the viewpoint of facilitating temperature control. Note that the installation position and other configurations of the heater 111 can be determined in various ways depending on the configuration of the processing tank 101 and the properties of the object to be processed. For example, in FIG. 2, the heater 111 is disposed at the bottom of the wall 101a, but it may also be disposed to the side or above the wall 101a.

[0019] The second heating unit 120 supplies heated gas to the storage section 101b. In other words, the second heating unit 120 has the function of directly heating the interior of the storage section 101b with hot air. In this embodiment, the second heating unit 120 has an air supply section 121, an exhaust section 122, an air blower section 123, and a heating section 124. In this embodiment, the second heating unit 120 constitutes a hot air circulation type heating unit that heats the gas exhausted from the storage section 101b by operating the air blower section 123 and supplies the gas to the storage section 101b. By supplying the circulated gas to the storage section 101b, exhaust heat can be recovered and energy efficiency can be improved. The gas used in the second heating unit 120 is not particularly limited and can be air, an inert gas such as nitrogen, or the like.

[0020] The gas supply unit 121 supplies gas to the storage unit 101b. In this embodiment, the gas supply unit 121 is configured as a gas passage that connects the storage unit 101b and the blower unit 123 (heater unit 124). The gas supply unit 121 is configured, for example, with one or more tubular members, including a tubular member that is provided so as to penetrate the wall 101a of the treatment tank 101.

[0021] The exhaust section 122 exhausts gas from the storage section 101b. In this embodiment, the exhaust section 122 is configured as a gas passage connecting the blower section 123 and the storage section 101b. The exhaust section 122 is configured, for example, with one or more tubular members including a tubular member provided to penetrate the wall section 101a of the treatment tank 101. From the viewpoint of efficient gas circulation, the exhaust section 122 is preferably arranged on the wall section 101a so as to face the gas supply section 121 across the storage section 101b.

[0022] Blower 123 blows gas to air supply unit 121. Blower 123 is formed of a blower such as a fan, a blower, or a compressor. Blower 123 is disposed between air supply unit 121 and exhaust unit 122.

[0023] The heating unit 124 heats the gas supplied to the accommodation unit 101b. The heating unit 124 may be disposed on the exhaust side of the air blower 123 as shown in FIG. 1, or on the air supply side. The heating unit 124 may be connected to the air blower 123 as shown in FIG. 1, or may be disposed separately. The heating unit 124 is composed of a heater that heats the gas, and is preferably composed of an electric heater from the viewpoint of facilitating temperature control. The configuration of the heater constituting the heating unit 124, such as the heating method and installation position, can be determined in various ways depending on the configuration of the treatment tank 101 and the properties of the object to be treated.

[0024] Furthermore, in this embodiment, the second heating unit 120 has a flow rate adjustment unit 125 that adjusts the flow rate of the gas supplied to the accommodation section 101b. The flow rate adjustment unit 125 may be disposed in the gas supply section 121 as shown in FIG. 1 , or may be disposed in the exhaust section 122. The flow rate adjustment unit 125 is configured by a flow rate adjustment member such as a damper or a valve, and is configured to be able to adjust the flow rate of the gas in the gas supply section 121. By having the flow rate adjustment unit 125 in the second heating unit 120, the flow rate of the gas supplied to the accommodation section 101b can be adjusted, which can contribute to temperature control of the accommodation section 101b.

[0025] The exhaust treatment unit 130 removes harmful substances contained in the gas exhausted from the accommodation unit 101b and discharges the treated gas to the outside of the treatment device 100. In the illustrated example, the exhaust treatment unit 130 has a branch path 131, a catalytic treatment unit 132, and an exhaust path 133.

[0026] The branch path 131 connects the second heating unit 120 and the catalytic treatment section 132. The branch path 131 is composed of a tubular member or the like that branches off from the second heating unit 120 to the exhaust treatment section 130. As shown in FIG. 1, the branch path 131 may be connected to the air intake section 121 of the second heating unit 120, or may be connected to the exhaust section 122 (see FIG. 5). By arranging the branch path 131 on the exhaust side of the flow rate adjuster 125, the flow rate of gas adjusted by the flow rate adjuster 125 can adjust the inflow of gas into the exhaust treatment section 130.

[0027] The catalytic treatment unit 132 has a heat source and a catalyst, and removes harmful substances contained in the gas by bringing the gas heated by the heat source into contact with the catalyst. The catalyst can be, for example, a solid catalyst containing fine particles of a precious metal (platinum, palladium, rhodium, ruthenium, etc.) on its surface. Such a solid catalyst can remove harmful substances such as carbon monoxide (CO) and hydrocarbons (HC), thereby increasing the safety of the gas. The heat source can be, for example, a heater, as long as it can heat the gas to a temperature at which the catalyst exerts its catalytic action.

[0028] The exhaust path 133 exhausts the gas that has passed through the catalytic treatment section 132 and been treated to the outside of the treatment device 100. The exhaust path 133 is also made up of a tubular member or the like.

[0029] The control unit 140 is configured as a processor that controls each unit of the processing device 100, and specifically includes a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), etc. Furthermore, the processing device 100 may have an operation panel (not shown) that is connected to the control unit 140 and allows a user to perform input operations.

[0030] The configuration of the processing device 100 is not limited to the above example and can be modified in various ways. For example, in the processing device 100, the rotation axis C of the shaft portion 102a does not necessarily have to extend horizontally, and may be tilted relative to the horizontal plane. However, to effectively obtain the stirring effect due to gravity in the processing device 100, it is necessary that at least the rotation axis C of the shaft portion 102a be tilted relative to the vertical direction, and it is preferable that the angle of the rotation axis C of the shaft portion 102a with respect to the horizontal plane is small. Specifically, in the processing device 100, it is preferable that the angle of the rotation axis C of the shaft portion 102a with respect to the horizontal plane is 30° or less. Other variations in the configuration will be described later.

[0031] [Method for manufacturing granular material] In this embodiment, the method for producing granular material includes a preparation step S01, a heating and stirring step S02, a cooling step S03, a storage determination step S04, and a storage step S05, as shown in Fig. 4. The method for producing granular material in this embodiment is performed using the processing device 100 described above.

[0032] In the preparation step S01, the material to be treated is accommodated in the accommodation section 101b, which is the internal space of the treatment tank 101. The amount of the material to be treated can be set so that the volume of the granular material to be produced exceeds at least a part of the stem section 102a. Note that this step is not performed in the second and subsequent treatments that are performed after the accommodation step S05, which will be described later.

[0033] In the heating and stirring step S02, the object to be processed accommodated in the accommodation section 101b is heated and stirred to generate granular material.

[0034] In this step, the accommodation section 101b is heated to 180°C or higher and 400°C or lower by a first heating unit 110 that heats the wall 101a of the treatment tank 101 and a second heating unit 120 that supplies heated gas to the accommodation section 101b. By setting the heating temperature to 180°C or higher and 400°C or lower, the object to be treated can be thermally decomposed while suppressing the volatilization of carbon compounds, thereby producing a carbide with a high carbon ratio. Note that the heating temperature in this step may be maintained at the maximum temperature between 180°C and 400°C or lower, or may vary within the above temperature range.

[0035] In this step, heater 111 of first heating unit 110 heats wall portion 101a, thereby heating storage portion 101b from the outside. Furthermore, in second heating unit 120, by operating air blower 123 and heater 124, gas is exhausted from storage portion 101b by exhaust portion 122, the exhausted gas is heated by heater 124, and the heated gas is supplied to storage portion 101b from air supply portion 121. This allows the interior of storage portion 101b to be directly heated by heated gas (hot air), allowing storage portion 101b to be heated efficiently and, as will be described later, facilitating control of the temperature rise rate.

[0036] In this step, the material to be treated is agitated by rotating the agitation shaft 102 in the storage section 101b. This crushes the material to be treated, increasing heating efficiency, and the agitation allows the material to be heated uniformly. Furthermore, agitation of the material to be treated suppresses adhesion of the material during the evaporation of water and pyrolysis process, making it easier to generate granules.

[0037] In the cooling step S03, after the heating and stirring step S02 and before the storing step S05, the storing section 101b is cooled to 100° C. or less, thereby cooling the produced granules.

[0038] , In this step, for example, by operating the air blower 123 of the second heating unit 120, a cooling gas is supplied from the air supply unit 121 of the second heating unit 120 to the storage unit 101b. The cooling gas can be a gas such as an inert gas or air adjusted to a temperature lower than that in the heating and stirring step S02. Specifically, the cooling gas can be obtained by stopping the heating unit 124 or setting the heating unit 124 to a temperature lower than that in the heating and stirring step S02 (for example, 100°C or lower). The temperature reached in the storage unit 101b in the cooling step S03 is preferably a temperature at which the production status of the granular material can be confirmed and the granular material can be recovered, and in which the granular material has accumulated heat in the storage step S05 described below, and is preferably, for example, 20°C or higher and 80°C or lower.

[0039] In this step, the workpiece may be agitated while being cooled by rotating the agitation shaft 102. This allows the viscosity to be reduced and finely crushed granules with small particle size to be formed, even if the workpiece contains a thermoplastic resin that tends to increase in viscosity during the cooling process. Another advantage of cooling the workpiece while agitating it is that the cooling efficiency can be improved.

[0040] In the accommodation determination step S04, it is determined whether or not a new workpiece is accommodated (S04). If it is determined that a new workpiece is accommodated (Yes in S04), the next accommodation step S05 is performed. If it is determined that a new workpiece is not accommodated (No in S04), the process ends. In this step, the user of the processing device 100 may make the determination, or the control unit 140 may perform the determination process. If the control unit 140 makes the determination, the control unit 140 may determine the end of the process based on information from a monitoring device, such as a weighing scale that measures the weight of the workpiece in the accommodation unit 101b or an imaging device that captures image information of the inside of the accommodation unit 101b. Furthermore, the control unit 140 may be configured to determine whether the heating and stirring step S02 and / or the cooling step S03 have been performed a predetermined number of times, and to end the process if it is determined that the predetermined number of times have been performed.

[0041] In the storing step S05, new objects to be processed including waste are stored in the storage section 101b.

[0042] In this step, new processing objects are accommodated in the accommodation unit 101b, with at least some of the granules remaining so that the volume of the granules exceeds at least a portion of the shaft portion 102a. The volume of the granules is determined as the vertical height L of the surface of the granules smoothed along a horizontal plane. The volume of the granules that will result in such a volume is set according to the position of the stirring shaft 102, but is preferably, for example, 25% or more of the volume of the accommodation unit 101b. Note that in this step, it is sufficient that only the granules that will result in a volume exceeding at least a portion of the shaft portion 102a remain in the accommodation unit 101b, and any granules greater than this may be collected.

[0043] After the containing step S05, the heating and stirring step S02, the cooling step S03, and the containing determination step S04 are repeatedly performed.

[0044] As described above, in the heating and stirring step S02 of this embodiment, by using the second heating unit 120 in addition to the first heating unit 110 for heating, the temperature uniformity within the storage unit 101b can be improved even when the volume of the storage unit 101b is increased. This allows the temperature within the storage unit 101b to be accurately controlled, and the progress of thermal decomposition of the material to be treated and the accompanying volatilization of carbon compounds can be controlled. Furthermore, by using two heating units for heating, the temperature rise rate within the storage unit 101b and the carbonization rate of the material to be treated can be increased, thereby improving processing efficiency. Furthermore, by shortening the processing time, energy consumption during processing can be reduced.

[0045] Furthermore, in the storage step S05 of this embodiment, a new workpiece is stored in the storage section 101b while leaving a sufficient amount of the generated granular material, allowing the generated granular material to function as a stirring medium in the subsequent heating and stirring step S02. Specifically, by stirring both the granular material and the workpiece, contact with the granular material creates fine scratches on the surface of the workpiece, forming starting points for crushing. This facilitates the crushing of the workpiece, and the surface area of ​​the workpiece is increased, thereby improving heating efficiency. Furthermore, by stirring the granular material and the workpiece, the granular material covers a wide area of ​​the crushed workpiece, allowing the heat stored in the granular material to be transferred to a wide area of ​​the workpiece. This improves the uniformity of heating of the workpiece and improves heating efficiency. Furthermore, by leaving the generated granular material so that it exceeds at least a portion of the shaft portion 102a, the entire remaining granular material is stirred by the rotation of the stirring shaft 102, allowing it to effectively function as a stirring medium. Therefore, according to the storing step S05 of this embodiment, the objects to be processed can be crushed, stirred, and heated efficiently, and the generation of granules can be promoted.

[0046] In this way, in this embodiment, by crushing and granulating the material to be treated through the heating and stirring step S02, a highly uniform recycled material can be produced, and the produced granules can be effectively used as a stirring medium for subsequent treatments. Therefore, the method for producing granules of this embodiment can efficiently produce recycled material with a high carbon content.

[0047] [Configuration example for controlling heating temperature] In the heating and stirring step S02, the rate of temperature rise in the storage section 101b can be controlled by the first heating unit 110, the second heating unit 120, and the flow rate adjuster 125. Using two heating units, as described above, can uniformly maintain the temperature within the storage section 101b and increase the number of parameters for controlling the heating temperature, making it easier to control the rate of temperature rise. For objects with a high moisture content, the flow rate adjuster 125 can be opened, for example, by widening the valve of the flow rate adjuster 125 during the process of drying the moisture, thereby increasing the airflow speed and accelerating the drying of the objects. After the objects have dried, the airflow speed can be reduced, and the temperatures of the first heating unit 110, which heats the storage section 101b from the outside, and the second heating unit 120, which heats the storage section 101b from the inside, can be coordinated to achieve uniform pyrolysis. In this case, the temperature difference between the heating temperatures of the first heating unit 110 and the second heating unit 120 is preferably within ±20°C, more preferably within ±10°C, in order to prevent uneven heating of the workpiece.

[0048] In this embodiment, a specific method for controlling the temperature rise rate in the heating and stirring step S02 may be, for example, to maintain the parameters of the first heating unit 110 and the second heating unit 120 constant. Alternatively, a parameter of one of the first heating unit 110 or the second heating unit 120 may be maintained constant while a parameter of the other may be changed. Alternatively, the parameters of both the first heating unit 110 and the second heating unit 120 may be changed. Specific parameters of the first heating unit 110 include the set temperature (output) of the heater 111. Specific parameters of the second heating unit 120 include the set temperature (output) of the heating section 124, the output of the blower 123, and the flow rate of the flow rate adjuster 125. These controls may be controlled by the control unit 140 based on input operations via an operation panel (not shown), or may be automatically controlled by the control unit 140 based on the monitoring results of the temperature of the storage section 101b, etc.

[0049] Alternatively, the temperature of the accommodation section 101b may be monitored by, for example, monitoring the temperature of the gas in the exhaust section 122 and controlling the temperature rise rate of the accommodation section 101b based on the monitored temperature. In this example, the second heating unit 120 further includes a temperature sensor, such as a thermocouple, that measures the temperature of the gas disposed in the exhaust section 122 (not shown). Because the gas in the exhaust section 122 is exhausted from the accommodation section 101b, the temperature reflects the temperature inside the accommodation section 101b. This allows the temperature inside the accommodation section 101b to be measured indirectly by utilizing the configuration of the second heating unit 120, even without disposing a temperature sensor inside the accommodation section 101b. Therefore, even if the workpiece contains a thermoplastic resin, adhesion of the molten thermoplastic resin to the temperature sensor can be prevented, thereby suppressing deterioration in the maintainability and measurement accuracy of the temperature sensor.

[0050] Furthermore, from the viewpoint of more accurate temperature monitoring of the accommodating section 101b, the temperature of the gas in the gas supply section 121 may be monitored in addition to the temperature in the exhaust section 122, and the rate of temperature rise of the accommodating section 101b may be controlled based on the temperatures monitored in the exhaust section 122 and the gas supply section 121. In this case, the second heating unit 120 further includes a temperature sensor (not shown) disposed in the gas supply section 121. By calculating the difference in temperature between the gas supply section 121 and the exhaust section 122, it is possible to detect the temperature rise of the accommodating section 101b due to the supply of heated gas. This makes it possible to more accurately control the rate of temperature rise of the accommodating section 101b.

[0051] [Configuration example for controlling the temperature drop] In the cooling step S03, the temperature of the gas in the exhaust section 122 may also be monitored, and the rate of temperature decrease in the storage section 101b may be controlled based on the monitored temperature. This temperature monitoring may be performed by a temperature sensor disposed in the exhaust section 122. The rate of temperature decrease in the storage section 101b may be adjusted by, for example, the output of the blower section 123 of the second heating unit 120. For example, from the viewpoint of improving processing efficiency, the rate of temperature decrease is preferably 1°C / min or more, more preferably 5°C / min or more, and in order to obtain stable granular material, the rate of temperature decrease is preferably 1°C / min or less, more preferably 0.5°C / min or less. In this case, the temperature of the gas may also be monitored in the gas supply section 121 in addition to the gas exhaust section 122, and the rate of temperature decrease in the storage section 101b may be controlled based on the temperatures monitored in the exhaust section 122 and the gas supply section 121.

[0052] [Example of exhaust treatment configuration] In this embodiment, it is preferable to perform an exhaust treatment to remove harmful substances contained in the gas exhausted from the storage section 101b. In the example shown in FIG. 1, the gas exhausted from the storage section 101b may be gas exhausted by the exhaust section 122 of the second heating unit 120. The exhaust treatment is performed, for example, in at least one of the heating and stirring step S02 or the cooling step S03. In the exhaust treatment of this embodiment, gas containing water vapor is generated by evaporation or thermal decomposition of the treated object, and excess gas in the exhaust section 122 flows into the branch path 131, where harmful substances such as carbon monoxide (CO) are removed in the catalytic treatment section 132. This improves the safety of the gas exhausted from the exhaust path 133 to the outside of the treatment device 100, thereby achieving a carbonization treatment with low environmental impact.

[0053] [Example of treatment tank configuration] In this embodiment, as illustrated in Fig. 2, the height H2 of the shaft 102a in the vertical direction from the bottom surface 101c of the storage unit 101b is preferably 1 / 2 or less of the maximum height H1 of the storage unit 101b in the vertical direction. This makes it easier to leave the generated granules so that their volume exceeds at least a portion of the shaft 102a, and further makes it easier to store a sufficient amount of new workpieces in the storage unit 101b. Note that the height H2 of the shaft 102a is the height of the rotation axis C of the shaft 102a. Furthermore, in order to more effectively exert the above-mentioned effects, the height H2 is preferably 1 / 3 or less of the maximum height H1.

[0054] [Modification of the first heating unit] The first heating unit 110 is not limited to the above-described configuration, and as shown in FIGS. 5 and 6, the first heating unit 110 may be configured to heat the inside of the wall portion 101a with gas.

[0055] The first heating unit 110 shown in FIGS. 5 and 6 can heat the wall portion 101a by supplying heated gas to the inside of the wall portion 101a. In this example, the wall portion 101a has a space portion 101d that diffuses the supplied gas. The space portion 101d is configured to conduct heat to the inner surface of the wall portion 101a, and may be, for example, a space formed inside the wall portion 101a or a tubular member or the like disposed inside the wall portion 101a. The arrangement of the space portion 101d is not particularly limited, but it is preferable that the space portion 101d be disposed over a wide area of ​​the wall portion 101a, and more preferably that the space portion 101d be disposed over the entire wall portion 101a.

[0056] 5 and 6, the first heating unit 110 includes an in-wall air supply section 112, an in-wall exhaust section 113, a blower 114, and a heater 115. In this example, the first heating unit 110 operates the blower 114 to exhaust gas from the space 101d via the in-wall exhaust section 113, heat the exhausted gas via the heater 115, and supply the heated gas from the in-wall air supply section 112 to the space 101d. This configures the first heating unit 110 as a hot air circulation type heating unit. The gas used in the first heating unit 110 is not particularly limited and may be air, an inert gas such as nitrogen, or the like.

[0057] The in-wall gas supply section 112 supplies gas to the space 101d inside the wall 101a. In this embodiment, the in-wall gas supply section 112 is configured as a gas passage connecting the space 101d and the heating section 115. The in-wall gas supply section 112 is configured, for example, with one or more tubular members including a tubular member connected to the space 101d.

[0058] The in-wall exhaust section 113 exhausts gas from the space 101d inside the wall 101a. In this embodiment, the in-wall exhaust section 113 is configured as a gas passage that connects the blower 114 and the space 101d. The in-wall exhaust section 113 is configured with one or more tubular members, including a tubular member connected to the space 101d, for example.

[0059] The air blowing section 114 blows gas to the in-wall air supply section 112. The air blowing section 114 is configured with an air blower such as a fan, a blower, or a compressor. In the example shown in Fig. 5, the air blowing section 114 is arranged on the exhaust side of the heating section 115, but it may also be arranged on the air supply side.

[0060] The heating unit 115 heats the supplied gas. The heating unit 115 is configured with a heater, and is preferably configured with an electric heater from the viewpoint of facilitating temperature control. Note that the configuration of the heater constituting the heating unit 115, such as the heating method and installation position, can be determined in various ways depending on the configuration of the processing tank 101, the properties of the object to be processed, etc.

[0061] Furthermore, the first heating unit 110 may have other configurations as necessary. In the example shown in Fig. 5, the first heating unit 110 further has a first valve member 116 that can take in outside air and a second valve member 117 that can exhaust air. This allows the first heating unit 110 to efficiently perform cooling in the cooling step S03.

[0062] The first heating unit 110 configured as described above allows the heated gas to heat a wide range of the inner surface of the wall 101a, and therefore the storage unit 101b can be heated efficiently even if the volume of the storage unit 101b is increased. Furthermore, by configuring the first heating unit 110 as a circulation-type heating unit, exhaust heat can be recovered to improve energy efficiency. Therefore, with this configuration, the volume of the storage unit 101b can be increased while reducing energy consumption, and processing efficiency can be further improved.

[0063] [Modification of the second heating unit] The arrangement of the heating section 124 and the blower section 123 in the second heating unit 120 is not limited to the example in FIG. 1, and the blower section 123 may be arranged on the exhaust side of the heating section 124, as illustrated in FIG.

[0064] [Example of oxygen supply unit configuration] Furthermore, as illustrated in FIG. 5, the processing apparatus 100 may have an oxygen supply unit 150 that supplies oxygen to the gas exhausted from the storage unit 101b. In the example illustrated in FIG. 5, the oxygen supply unit 150 is connected to the branch path 131. The gas exhausted from the storage unit 101b may be gas exhausted by the exhaust unit 122 of the second heating unit 120 and introduced into the branch path 131. In the heating and stirring step S02 and / or the cooling step S03 in which the second heating unit 120 is operating, supplying oxygen to the gas exhausted from the storage unit 101b can oxidize carbon monoxide (CO) to generate carbon dioxide (CO), thereby suppressing the emission of harmful carbon monoxide. Note that the oxygen supply unit 150 is not limited to being connected to the branch path 131, and may be connected to the exhaust unit 122 of the second heating unit 120.

[0065] A specific configuration of the oxygen supply unit 150 includes, for example, a fan that takes in outside air and a valve member such as a valve that adjusts the intake of outside air. This allows outside air containing oxygen to be supplied to the exhaust gas. Alternatively, instead of a fan that takes in outside air, the oxygen supply unit 150 may include a container that stores oxygen gas and supply the oxygen gas via a valve member. The amount of oxygen supplied by the oxygen supply unit 150 can be appropriately adjusted to an amount that reduces carbon monoxide without reducing the carbon ratio of the granular material.

[0066] [Example of granular material composition] In the method for producing granular materials according to the embodiment, as described above, granular materials having a particle size of 10 μm or more and 5 cm or less are produced by heat-treating a material to be treated, including waste. The structure of the granular materials will be described below.

[0067] The carbon ratio of the granules is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass. This allows the granules to be effectively used as a recycled material with the functions of charcoal. The carbon ratio of the granules can be measured using an organic elemental analyzer.

[0068] The calorific value of the granules is preferably 20 MJ / kg or more, more preferably 22.5 MJ / kg or more, and even more preferably 25 MJ / kg. This allows for the production of granules that are easily combustible and can be used as fuel. The calorific value of the granules can be the total calorific value measured using a calorimeter such as a bomb calorimeter in accordance with JIS M8814:2003.

[0069] The moisture content of the granules is preferably 10% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. This allows for the production of sufficiently dried, combustible granules. The moisture content is measured according to the nitrogen stream drying loss measurement method described in JIS M8812:2004.

[0070] The granules may contain Na. This allows for the production of granules containing inorganic components suitable for use as fertilizers or soil improving compositions. The Na content of the granules is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and preferably 10.0% by mass or less, more preferably 8.0% by mass or less. The Na-containing granules can be obtained, for example, by treating a material to be treated, including an absorbent article containing a superabsorbent polymer containing a sodium salt.

[0071] The oxygen index of the granules is preferably less than 29%, more preferably less than 27%. This allows for the production of granules that are highly combustible and highly useful as fuel. The oxygen index is the minimum oxygen concentration (%, volume fraction) of a mixed gas of oxygen and nitrogen at 23°C ± 2°C required to maintain flaming combustion of a sample under specified conditions, and is measured specifically according to the oxygen index measurement procedure described in JIS K7201-2:2007.

[0072] From the viewpoint of increasing the carbon ratio, the hydrogen ratio of the granules is preferably 15 mass % or less, preferably 12 mass % or less, more preferably 10 mass % or less. The hydrogen ratio of the granules can be measured by an organic elemental analyzer.

[0073] The oxygen ratio of the granules is preferably 15% by mass or more, more preferably 17% by mass or more, from the viewpoint of increasing combustibility, and is preferably 35% by mass or less, more preferably 33% by mass or less, from the viewpoint of increasing the carbon ratio. The oxygen ratio of the granules can be measured using an organic elemental analyzer.

[0074] It is also preferable that the surface of the granules has a fine uneven structure. This is thought to enable the granules to exhibit the same adsorption function as porous carbon. The fine uneven structure is an uneven structure that can be confirmed from an image of the granules taken at a magnification of 1000 to 1500 times.

[0075] The granules contain a lot of carbon and are easily combustible, so they can be used as part of a fuel. For example, they can be used as a substitute for fossil resources (such as coal). Furthermore, the granules can be effectively used as, for example, paper compositions, fiber compositions, soil improvement compositions, water treatment compositions, fuels, fertilizers, building materials such as heat insulating materials, adsorbents, detoxifiers, deodorizers, and the like.

[0076] Furthermore, a compact can be obtained by forming the granules of this embodiment into pellets. Such compacts are commonly used as fuel, fertilizer, etc., and can be suitably used as a substitute for conventionally used materials. The dimensions of the compact can be set appropriately depending on the application, but the maximum dimension can be, for example, 5 mm or more and 50 mm or less. The compact can be produced, for example, by a molding machine such as a pelletizer.

[0077] Second Embodiment Next, a second embodiment of the present invention will be described. Note that in this embodiment, the description common to the first embodiment will be omitted as appropriate.

[0078] As described above, the granular material can be used as fuel. Therefore, in this embodiment, as shown in Fig. 7, an embodiment will be described in which the granular material G is used as fuel to generate energy in an energy generating device 200, and the generated energy is used as a power source for a processing device 100.

[0079] The granules G are used in a form suitable for use as fuel in the energy generating device 200. For example, the fuel derived from the granules G may be the granules G themselves, or may be a solid fuel produced by molding the granules G.

[0080] The solid fuel may be in the form of pellets as described above, or may be in any other form such as briquettes or tablets. The solid fuel may contain, in addition to the granules G, binders and additives for molding, and other materials (RPF and wood chips). However, the content of the granules G in the solid fuel is preferably 5% by mass or more, and more preferably 10% by mass or more.

[0081] The energy generating device 200 may be any device that can generate energy to power the processing device 100 using fuel derived from the granular material G, and examples thereof include a boiler, a gasification device, a stove (e.g., a pellet stove), a power generation device, etc. Note that the "energy generating device 200" according to this embodiment is not limited to one device, but also includes a configuration in which multiple devices work together to generate energy.

[0082] The power source of the processing device 100 may include at least a portion of the energy generated by the energy generating device 200. Examples of the power source of the processing device 100 generated by the energy generating device 200 include electricity, energy derived from gas fuel, thermal energy used in the first heating unit 110 and / or the second heating unit 120, and thermal energy used in the catalytic treatment device 132 of the exhaust treatment device 130. The form of supply of thermal energy can be determined appropriately depending on the configuration of the energy generating device 200 and the configuration of the processing device 100, and examples include heated gas such as warm air (hot air), warm water (hot water), etc.

[0083] As described above, according to this embodiment, the processing apparatus 100 can be operated using energy derived from carbon fixed as granules G by the processing apparatus 100. This reduces the amount of fossil fuel used to operate the processing apparatus 100, and reduces greenhouse gas emissions throughout the entire manufacturing process of granules G. Therefore, according to this embodiment, not only can waste be recycled, but emissions of greenhouse gases such as CO2 during the waste recycling process can also be reduced, thereby realizing a recycling process with even lower environmental impact.

[0084] <Third embodiment> Next, a third embodiment of the present invention will be described. Note that in this embodiment, explanations common to the above-mentioned embodiments will be omitted as appropriate.

[0085] In the method for producing granular materials according to the third embodiment of the present invention, the power source of the processing equipment for producing the granular materials includes energy derived from renewable energy, from the viewpoint of further reducing greenhouse gas emissions associated with the recycling process. In this case, all or part of the power source of the processing equipment for producing the granular materials may be energy derived from renewable energy.

[0086] Renewable energy is an energy source that can be obtained from the natural environment and can be used perpetually without depletion, and examples thereof include solar power, wind power, hydroelectric power, geothermal power, biomass, etc. Energy derived from renewable energy includes electricity generated by solar power generation, electricity generated by wind power generation, electricity generated by hydroelectric power generation, electricity generated by geothermal power generation, thermal energy derived from hot water used in geothermal power generation, electricity generated by biomass power generation, etc.

[0087] Of these, in this embodiment, the renewable energy-derived energy preferably includes power generated by solar power generation. Solar power generation facilities have a high degree of freedom in terms of installation location and can be installed at a lower cost than facilities related to other renewable energies. In this way, by using power generated by solar power generation, it is possible to relatively easily introduce an energy supply facility derived from renewable energy.

[0088] Furthermore, in this embodiment, it is preferable that the solar-generated power includes stored solar-generated power. For storing power, a power storage facility including a storage battery or the like can be used. This allows, for example, solar-generated power to be stored during the day and supplied to the processing device 100 at night to operate the processing device 100. Alternatively, by using the stored power, it is possible to stably supply power to the processing device 100 regardless of the weather. This allows the processing device 100 to stably use solar-generated power regardless of the weather or time.

[0089] As described above, according to this embodiment, at least a portion of the power source required for the operation of the treatment device 100 can be derived from renewable energy that does not emit greenhouse gases such as CO2. Therefore, it is possible to reduce the amount of greenhouse gas emissions associated with the operation of the treatment device 100, and it is also possible to reduce the amount of greenhouse gas emissions in the entire waste recycling process.

[0090] In addition, this embodiment can be implemented in combination with the second embodiment. This allows part of the power source of the processing device 100 to be energy generated using fuel derived from granules, and the other part to be energy derived from renewable energy. Therefore, even if either energy generated using fuel derived from granules or energy derived from renewable energy is insufficient as the power source for the processing device 100, by using both of them, the power source for the processing device 100 can be sufficiently supplied with energy that has a low environmental impact. This makes it possible to more reliably reduce greenhouse gas emissions related to the recycling process.

[0091] <Other embodiments> Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the gist of the present invention.

[0092] For example, a crushing process may be performed before the heating and stirring step S02 to crush the waste-containing materials to be treated. This crushing process may be performed as long as the materials to be treated are roughly crushed. For example, the maximum size of the fragments of the materials to be treated after the crushing process is 50 mm or more and 200 mm or less. In the crushing process, the materials to be treated may be crushed by a crushing device or the like separate from the treatment device 100, or by providing a crushing unit in the treatment device 100. The crushing device may have, for example, a crushing shaft including multiple rotary blades that rotates around a rotation axis, and is configured to crush the materials to be treated by the rotation of the multiple rotary blades. The crushing unit provided in the treatment device 100 also has a crushing shaft that is attached to the storage section 101b or a treatment space separate from the storage section 101b. When a crushing shaft is provided in the storage section 101b, it is preferable to provide the crushing shaft between the inlet of the storage section 101b and the stirring shaft 102 (for example, above the storage section 101b) so as not to affect the stirring by the stirring shaft 102.

[0093] In this embodiment, the disruption treatment is preferably carried out at room temperature. Here, room temperature refers to a temperature that does not involve heating the disruption space, for example, 5°C to 40°C. By carrying out the disruption treatment at room temperature, energy consumption can be reduced because no energy for heating is required during the disruption treatment.

[0094] Furthermore, for example, the component concentrations of the gas exhausted from the storage unit 101b may be monitored during at least one of the heating and stirring step S02 or the cooling step S03. In this example, the processing device 100 has a gas component concentration measuring device disposed in the exhaust unit 122 or the exhaust treatment unit 130. The measured gas component concentrations include, for example, oxygen concentration, carbon monoxide concentration, carbon dioxide concentration, and concentrations of other harmful substances. This makes it possible to obtain information on the composition of the exhausted gas, which can be useful for process control and reducing the emission of harmful substances.

[0095] Furthermore, in the above embodiment, an example was shown in which the manufacturing method of granular material includes the accommodation determination step S04, but the accommodation step S05 may be performed without performing the accommodation determination step S04.

[0096] The cooling step S03 of cooling the inside of the accommodation section 101b by the air blower 123 is not essential, and for example, the accommodation section 101b may be cooled naturally.

[0097] The exhaust treatment is not limited to the above example either, and may be performed in a device separate from the treatment device 100, for example.

[0098] The configuration of the processing apparatus 100 used to produce granular materials is not limited to the above example, and for example, the first heating unit may be configured to have a heater installed inside the wall portion 101a, or may be configured to heat the inside of the wall portion 101a with a heated liquid. Furthermore, the second heating unit may exhaust the gas exhausted from the storage portion 101b without circulating it. [Example]

[0099] The processing apparatus shown in Fig. 1 described in the above embodiment was used to carry out the production process of granular materials according to the examples of the present invention. On the other hand, a carbonization process according to the comparative examples of the present invention was carried out using a commercially available hybrid pyrolysis carbide production machine. In the processes of the examples and comparative examples, the processed material was a diaper that had been moistened to simulate a used diaper.

[0100] The hybrid pyrolysis carbide production machine according to the comparative example had a configuration similar to that of the carbonization furnace described in Patent Document 2, including a main body for pyrolyzing waste and an exhaust section for exhausting exhaust gases generated during the pyrolysis of waste. The main body included a pyrolysis furnace tapered downward, an inlet at the top of the pyrolysis furnace, multiple thermal conduction heaters located at the bottom of the pyrolysis furnace, an infrared layer formed within the pyrolysis furnace below the thermal conduction heaters and consisting of multiple ceramic balls, an agitator located within the pyrolysis furnace below the infrared layer and for dropping materials accumulated in the infrared layer, and an outlet for materials to be treated located at the bottom of the main body. In other words, the pyrolysis furnace corresponding to the storage section of this device did not have an agitator shaft, and the storage section was designed for high-temperature heat treatment.

[0101] As shown in Table 1, in the process according to the example, a heating and stirring step in which the material to be treated was heated and stirred, and a storage step in which new material to be treated was stored in a storage unit while leaving at least a portion of the granules so that the volume of the generated granules exceeded at least a portion of the stem, were repeated multiple times. In the heating and stirring step, the storage unit was heated to approximately 225°C. This resulted in granules with a particle size of 10 μm to 5 cm.

[0102] On the other hand, in the comparative example, a commercially available hybrid pyrolysis carbide production machine was used to perform a heating step and a step of placing new workpieces into the pyrolysis furnace while leaving the product obtained in the heating step. However, the workpieces could not be stirred while being heated during the heating step. Furthermore, in the heating step of the comparative example, a thermal conduction heater and an infrared layer were located below the pyrolysis furnace. The temperature was approximately 100°C above the pyrolysis furnace and increased downward, reaching approximately 800°C near the thermal conduction heater. In the comparative example, due to the high heat treatment temperature, a powder finer than granular material was produced. The powder that accumulated in the infrared layer was dropped below the infrared layer by the stirring device, so the step of placing new workpieces while the product remained in the pyrolysis furnace could not be performed.

[0103] [Table 1]

[0104] Furthermore, when comparing the processes of the Example and Comparative Example from the viewpoint of processing efficiency, the Example performs heat treatment using two heating units to reach a heating temperature of approximately 225°C, while the Comparative Example performs heat treatment up to a maximum of 800°C using a thermal conduction heater and an infrared layer to support it. Therefore, the processing using the processing device of the Example was a processing method with a lower environmental impact, and was able to efficiently produce a product with a high carbon ratio.

[0105] Furthermore, to evaluate the products, the products produced by the treatments of the Examples and Comparative Examples were analyzed using an organic elemental analyzer (UNICUBE (device name), manufactured by Elementar Co., Ltd.) for CHNO analysis, and the carbon ratio in the Examples was 57.0%, while the carbon ratio in the Comparative Examples was 24.8%. Furthermore, when the calorific values ​​of the products were measured using a bomb calorimeter, the calorific value of the granules in the Examples was 26.8 MJ / kg, while the calorific value of the product in the Comparative Examples was 6.74 MJ / kg.

[0106] These evaluations revealed that the granules in the examples had a higher carbon ratio and calorific value than the products in the comparative examples. Therefore, the granules in this embodiment can be used as part of a fuel, and can be effectively used, for example, as a substitute for fossil resources (such as coal). In addition, the granules can be effectively used, for example, as paper compositions, fiber compositions, soil improvement compositions, water treatment compositions, fuels, fertilizers, building materials such as insulation materials, adsorbents, detoxifiers, deodorizers, etc. [Explanation of symbols]

[0107] 100... Processing device 101... Treatment tank 101a...Wall part 101b...container 102...Agitator shaft 102a...wing part 102b...Shaft part 110...First heating unit 120...Second heating unit

Claims

1. A method for producing granular materials using waste, comprising: a heating and stirring step of heating and stirring the material to be treated, including the waste, in a storage section, which is the internal space of the treatment tank, to generate granular material; a storing step of storing a new object to be processed in the storing section after the heating and stirring step; Including, In the heating and stirring step, The container is heated to 180°C or higher and 400°C or lower by a first heating unit that heats a wall portion of the treatment tank and a second heating unit that supplies heated gas to the container, and The material to be processed is stirred by rotating an agitation shaft in the storage unit, the agitation shaft having a shaft portion rotatable around a rotation axis extending in a direction intersecting the vertical direction and a plurality of blade portions provided at intervals along the rotation axis on the outer peripheral surface of the shaft portion, In the storing step, the new object to be processed is stored in the storage section while leaving at least a portion of the granular material so that the volume of the generated granular material exceeds at least a portion of the stem portion. A method for producing granular materials.

2. In the heating and stirring step, a temperature rise rate of the accommodation section is controlled by the first heating unit and the second heating unit. A method for producing the granular material according to claim 1.

3. The second heating unit is an air supply unit that supplies the gas to the storage unit; an exhaust unit that exhausts the gas from the storage unit; a blower that blows the gas to the air supply unit; a heating unit that heats the gas supplied to the storage unit, In the heating and stirring step, the air blowing unit and the heating unit are operated to exhaust the gas from the storage unit by the exhaust unit, heat the exhausted gas by the heating unit, and supply the heated gas to the storage unit from the air supply unit. A method for producing the granular material according to claim 1 or 2.

4. In the heating and stirring step, the temperature of the gas in the exhaust section is monitored, and a temperature rise rate of the container section is controlled based on the monitored temperature. A method for producing the granular material according to claim 3.

5. The method further includes a cooling step of cooling the storage unit to 100°C or less after the heating and stirring step and before the storage step, In the cooling step, the air blower is operated to supply cooling gas from the air supply unit of the second heating unit to the accommodation unit. A method for producing the granular material according to claim 3.

6. In the cooling step, a temperature of the cooling gas in the exhaust section is monitored, and a temperature decreasing rate of the accommodation section is controlled based on the monitored temperature. A method for producing the granular material according to claim 5.

7. an exhaust treatment for removing harmful substances contained in the gas exhausted from the storage section; A method for producing the granular material according to claim 1 or 2.

8. supplying oxygen to the gas exhausted from the storage section; A method for producing the granular material according to claim 1 or 2.

9. The height of the shaft portion in the vertical direction from the bottom surface of the storage portion is equal to or less than half of the maximum height of the storage portion in the vertical direction. A method for producing the granular material according to claim 1 or 2.

10. The carbon ratio of the granular material is 30% by mass or more. A method for producing the granular material according to claim 1 or 2.

11. The waste includes combustible waste. A method for producing the granular material according to claim 1 or 2.

12. The waste material includes a thermoplastic resin. The method for producing the granular material according to claim 11.

13. The waste material comprises cellulose. The method for producing the granular material according to claim 11.

14. The waste material includes absorbent articles. The method for producing the granular material according to claim 11.

15. The waste includes infectious waste. The method for producing the granular material according to claim 11.

16. The granular material produced in the heating and stirring step is used as fuel. A method for producing the granular material according to claim 1 or 2.

17. The energy generated using fuel derived from the granules is used to power a processing device that produces the granules. The method for producing the granular material according to claim 16.

18. The granular material-derived fuel includes a solid fuel produced by molding the granular material. A method for producing the granular material according to claim 16 or 17.

19. The power source of the processing device for producing the granular material includes energy derived from renewable energy, A method for producing the granular material according to claim 1 or 2.

20. The renewable energy-derived energy includes electricity generated by solar power generation. A method for producing the granular material according to claim 19.

21. The solar-generated electricity includes stored solar-generated electricity. A method for producing the granular material according to claim 20.

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