Woody biogas production system, woody biogasification method, woody biopellet manufacturing device and manufacturing method, torrefied carbide manufacturing device and torrefied carbide manufacturing method, and woody biofuel manufacturing device and woody biofuel manufacturing method

Abstract

In the present invention, a torrefied carbide is produced from a processing feedstock woody material, a torrefied carbide with increased energy is produced from the processing feedstock woody material, and a woody biogas with increased energy is produced from the torrefied carbide with increased energy. The present invention comprises a subcritical water reaction processing device, a woody biopellet production device, and a woody biogasification furnace. In the subcritical water reaction processing device, a torrefied carbide woody biomaterial is formed from a woody material, treating a cellulose component with a reduced molecular weight, a lignin component with a reduced molecular weight, and a plurality of hemicellulose-based monosaccharides that have coagulated with and become fixed to the cellulose component and the lignin component as primary components. In the woody biopellet production device, woody biopellets are produced from the torrefaction-processed woody biomaterial. In the woody biogasification kiln, a woody biogas is produced from the woody biopellets.

Description

Wood biogas generation system, wood biogasification method, wood biopellet manufacturing device and manufacturing method, semi-carbonized carbonized material manufacturing device and semi-carbonized carbonized material manufacturing method, wood biofuel manufacturing device and wood biofuel manufacturing method

[0001] The present invention relates to a wood biogas generation system, a wood biogasification method using a wood biogas generation system, a wood biopellet production device and a wood biopellet production method using a wood biopellet production device, a semi-carbonized carbonization production device and a semi-carbonized carbonization production method using a semi-carbonized carbonization production device, and a wood biofuel production device and a wood biofuel production method using a wood biofuel production device.

[0002] A known method involves torrefying wood material (also known as wood chips) and converting the resulting torrefied material into wood pellets. The wood material, i.e., wood chips, is fed into a rotary kiln at a constant rate using a constant-feed feeder. The furnace temperature during torrefying is 200 to 300°C, and the residence time is approximately 60 minutes. The torrefied material is then stored in a drum at the exit of the rotary kiln.

[0003] "Semi-carbonization," also known as "torrefaction," is a fuel conversion technology in which woody biomass is heated at 200-300°C in a low-oxygen environment to decompose organic matter into substances with a high carbon content. Semi-carbonization is known to increase energy density and improve crushability and water resistance, and some semi-carbonization processing equipment is known to be able to perform drying and semi-carbonization in one unit, thereby increasing the semi-carbonization speed by blowing hot air directly onto the raw material.

[0004] The International Energy Agency (IEA) defines "torrefaction" as "a heat treatment carried out at 250 to 320°C in a reduced oxygen atmosphere."

[0005] The pelletizing device used is a device capable of forming powdered semi-carbide into a cylindrical shape with a diameter of about 6 mm.

[0006] Large-scale production facilities with a capacity of tens of thousands of tons are being constructed mainly for Europe and the US. Japan has abundant forest resources, which make it easy to use them on a small scale, and it can also be used to replace fossil fuels with local resources, contributing to regional revitalization.

[0007] Local resources that can be used on a small scale include forest residues such as thinned wood and wind-fallen trees, as well as construction waste.

[0008] The main components of wood are polymers such as cellulose, hemicellulose, and lignin, with hemicellulose accounting for approximately 20% and cellulose and lignin accounting for 80%. When wood is heated, the polymer components are thermally decomposed into lower molecular weight components, and the remainder becomes a carbonized residue. Each of these components decomposes at different temperatures: hemicellulose decomposes at approximately 450 to 570 K (177 to 297°C), cellulose at 510 to 670 K (237 to 397°C), and lignin at 550 to 820 K (277 to 547°C).

[0009] A woody biogasification power generation system is known. The woody biogasification power generation system includes a fixed-bed gasifier, a cyclone, a scrubber, a cooling tower, a filter device, and a gas engine generator. The gas engine generator generates, for example, 80 kW of electricity.

[0010] Patent Document 1 describes that by holding the material for 5 to 90 minutes in a temperature range of 200 to 240°C, where hemicellulose decomposition proceeds slowly, the hemicellulose decomposition products volatilize and diffuse outside the carbonized material before charring. It also describes that the first-stage temperature is preferably 210 to 235°C and the carbonization time is preferably 15 to 60 minutes, and that the second-stage carbonization temperature is preferably 250 to 280°C and the carbonization time is 15 to 60 minutes.

[0011] Patent Document 2 describes a subcritical water treatment apparatus, and describes that a reaction vessel used in the subcritical water treatment apparatus has a double structure consisting of an outer vessel and an inner vessel housed inside the outer vessel.

[0012] Patent Document 3 describes a method for producing biomass solid fuel, which includes a step of hydrothermal carbonization of EFB (palm oil residue) at a temperature of 150 to 250°C and a pressure of 0.3 to 4.2 MPa (G).

[0013] In Non-Patent Document 1, Table 1: Classification of Biomass Gasifiers [6] lists fixed bed, fluidized bed, entrained bed, and rotary kiln gasifiers, and describes the gasification of wood chips. Non-Patent Document 1 also describes the use of high-temperature gasification temperatures, such as 700 to 1200°C.

[0014] JP 2020-45373 A Japanese Patent No. 4789595 A Japanese Patent No. 7252389 A

[0015] Journal of the Combustion Society of Japan, Vol. 49, No. 150 (2007) 228-235

[0016] A wood biogasification system is used to produce semi-carbonized charcoal from wood as a processing raw material, and then gasify the semi-carbonized charcoal in a wood biogasification furnace.The amount of semi-carbonized charcoal produced from wood is reduced, and a high amount of semi-carbonized charcoal with high energy is not obtained compared to the amount of wood as a raw material.

[0017] As mentioned above, Japan has many forest resources, and one local resource that can be used on a small scale is forest residues left in forests. To enable the effective use of forest residues that are dispersed on a small scale, to switch fuel from fossil fuels to forest residues, which are a local resource, and to contribute to the revitalization of local areas through this substitution, an effective method of utilizing forest residues is required.

[0018] In view of the above, the present invention employs a newly discovered method for utilizing subcritical water reaction treatment equipment, thereby adopting a "semi-carbonization method" that can be defined in a different form from the conventional "semi-carbonization method" defined by the IEA, and aims to obtain a large amount of semi-carbonized charcoal with higher energy than the amount of raw wood material from the amount of raw wood material, thereby generating a large amount of high-energy wood biogas.

[0019] The present invention provides a wood biogas generation system that produces semi-carbonized charcoal from wood material as a processing raw material and gasifies the semi-carbonized charcoal in a gasification furnace, the system comprising a subcritical water reaction treatment device, a wood biopellet generation device, and a wood biogasification furnace, wherein the subcritical water reaction treatment device produces semi-carbonized charcoal wood biomaterial mainly composed of low-molecular-weight cellulose components, low-molecular-weight lignin components, and a plurality of hemicellulose-based monosaccharides (e.g., xylose, mannose, arabinose, galactose, glucose) solidified and fixed to the cellulose components and lignin components, the wood biopellet generation device produces wood biopellets from the semi-carbonized wood biomaterial, and the wood biogas generation furnace produces wood biogas from the wood biopellets. In the wood biogas generation system, a wood biogas generation system that generates the semi-carbonized wood biomaterial consisting of a solid body and a powder, forms wood biopellets from a mixture of the powder or a powder generated from a portion of the solid body, forms a wood biofuel body from the solid body and the wood biopellets, and feeds the wood biofuel body into the wood biogasification furnace to generate wood biogas; and a wood biogas generation system that generates semi-carbonized char from wood material as a processing raw material and gasifies the semi-carbonized char in a gasification furnace, the system comprising: a subcritical water reaction treatment device, a wood biopellet generation device, and a wood biogasification furnace, the subcritical water reaction treatment device comprising an inlet for feeding the wood material as a processing raw material and a pressure vessel having an outlet for removing the semi-carbonized char, and a heat source for the subcritical water reaction treatment and the semi-carbonization treatment; The pressure vessel is composed of an outer cylindrical vessel and an inner cylindrical vessel, and an inner space within the inner cylindrical vessel and an outer space formed between the inner and outer cylindrical vessels are partitioned by the inner cylindrical vessel; a first heating means is provided for introducing steam into the inner space to heat the inner space; and a second heating means is provided for heating the inner space with the outer space; and the wood material is decomposed into smaller molecules in the subcritical water reaction treatment apparatus to produce a subcritical water reaction-treated wood biomaterial.When the wood material is carbonized, the relationship between temperature X and weight loss rate Y is expressed on an XY coordinate system as an S-shaped curve divided into three sections: the shoulder of the gradual weight loss line continuing into the sudden weight loss section, the S-shaped curve where the sudden weight loss section ends, and the end of the S-shaped curve of the gradual weight loss line; when the temperature in the inner space by the second heating means is set to the temperature of the shoulder of the S-shaped curve, a semi-carbonized wood biomaterial is formed from the wood biomaterial, the main components of which are low-molecular-weight cellulose components, low-molecular-weight lignin components, and hemicellulose-based polysaccharides solidified and fixed to these cellulose components and lignin components; and wood biopellets are produced from the semi-carbonized wood biomaterial in the wood biopellet production device. A wood biogas generation system characterized by generating wood biogas from the wood biopellets in the wood biogasification furnace at a temperature set at the part of the S-shaped curve where the weight decreases rapidly, or at a temperature set at the outlet part of the S-shaped curve where the weight gradually decreases. A wood biogas generation system that generates semi-carbonized charcoal from wood material as a processing raw material and gasifies the semi-carbonized charcoal in a gasification furnace, comprising a subcritical water reaction treatment device, a wood biopellet generation device, and a wood biogasification furnace, in which the subcritical water reaction treatment device forms semi-carbonized wood biomaterial mainly composed of low-molecular-weight cellulose components, low-molecular-weight lignin components, and hemicellulose-based polysaccharides solidified and fixed to the cellulose components and lignin components, the wood biopellet generation device generates wood biopellets from the semi-carbonized wood biomaterial, and the wood biogasification furnace generates wood biogas from the wood biopellets. We propose a wood biogas generation system characterized by the following.

[0020] In some literature, wood biopellets are sometimes called wood biomass pellets.

[0021] According to the present invention, as described above, by performing the subcritical water reaction treatment by hydrolysis, low molecular weight wood biomaterial is produced from the input wood material, and from the subcritical water reaction-treated wood biomaterial, a semi-carbonized charred wood biomaterial can be formed, whose main components are low molecular weight cellulose components, low molecular weight lignin components, and multiple hemicellulose-based monosaccharides that are solidified and fixed to these cellulose components and lignin components.

[0022] When the change in the temperature X of the woody material and the weight loss rate Y of the woody material is represented on the XY coordinate system by an S-shaped curve divided into three sections: the shoulder of the gradual weight loss line, the section continuing into the sudden weight loss section, the sudden weight loss section of the S-shaped curve, and the section where the sudden weight loss ends and the gradual weight loss line ends, the hemicellulose components that form the woody biomaterial are liquefied and solidified at the temperature set at the shoulder of the S-shaped curve, and multiple hemicellulose-based monosaccharides are fixed to the other components that form the woody biomaterial, namely, the low-molecular-weight cellulose components and low-molecular-weight lignin components, forming a woody biomaterial with the multiple hemicellulose-based monosaccharides fixed thereto and composed mainly of low-molecular-weight cellulose components and lignin components, and the woody biomaterial composed mainly of low-molecular-weight cellulose components and lignin components can be semi-carbonized.

[0023] The semi-carbonization process is carried out at a temperature of 150 to 220°C, which is lower than the temperature range used in conventional semi-carbonization processes, and therefore semi-carbonized wood material that retains 90 to 95% of the heat generated by the wood material before the process can be obtained in an extremely short time.

[0024] Furthermore, according to the present invention, woody biogas can be efficiently produced using the highly energy semi-carbonized carbonized material.

[0025] 1. Diagram showing an overview of a wood biogas generation system according to an embodiment of the present invention. 2. Diagram showing the configuration of a subcritical water reaction treatment apparatus according to an embodiment of the present invention. 3. Diagram showing the processing temperature and the weight change of wood material, with the processing temperature X and the weight change Y of wood material being represented as XY coordinates. 4. Diagram explaining the coagulation, fixation, and semi-carbonization process of multiple hemicellulose-based monosaccharides into low-molecular-weight cellulose components and lignin components that form wood biomaterial on the XY coordinate system. 5. Micrograph (1) of the product of wood material processed according to FIG. 5. 6. Micrograph (2) of the product of wood material processed according to FIG. 5. 7. Micrographs (3) and (4) of the product of wood material processed according to FIG. 5. 8. Diagram explaining the optimal semi-carbonization process. 9. Diagram showing manufactured wood biopellets. 10. Diagram showing the process of producing a wood biofuel body. 11. Diagram explaining the gasification process of wood biopellets. 12. Diagram explaining the areas used in the present invention on an XY coordinate system. 13. Diagram showing the steps of a wood biogas generation method according to an embodiment of the present invention.

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] FIG. 1 is a diagram showing an outline of a wood biogas generation system according to an embodiment of the present invention.

[0028] In FIG. 1, the woody biogas generation system 100 is mainly composed of a biopellet production device 2 and a biogas production device 3 connected to the biopellet production device 2 by a transport means 8 such as a transport vehicle.

[0029] The biopellet production apparatus 2 is composed of a subcritical water reactor 5 and a wood biopellet production apparatus 6, and a superheated steam generator 4 is attached to the biopellet production apparatus 2. Superheated steam is delivered to the subcritical water reactor 5.

[0030] Organic matter from forest residues (hereinafter referred to as forest residues) is processed into wood chips of any shape, i.e., wood material, collected by any means, and then input 8 into a subcritical water reactor 5. In this embodiment, forest residues are wood chips left in forests, wood chips are forest residues that have been processed by crushing or other methods, and wood material is used in a conceptual sense as wood chips, and wood material can be rephrased as wood chips and wood chips as wood material. A typical example of wood material is cedar, but various types of wood material are known.

[0031] Wood material 1 is subjected to subcritical water reaction treatment with superheated steam and semi-carbonized as described below, forming a semi-carbonized material, i.e., wood biomaterial. The subcritical water reactor 5 subjects the input wood material 1 to subcritical water reaction treatment, thereby forming wood biomaterial. Wood biomaterial can also be referred to as wood biomass material. Therefore, when wood material is subjected to subcritical water reaction treatment, it is called wood biomaterial. When wood biomaterial is subjected to subcritical water reaction treatment and pelletized, it is called wood biopellet material.

[0032] Subcritical water reactions involve the hydrolysis of high-molecular-weight organic substances into smaller molecules by confining high-temperature, high-pressure water in a pressure vessel. A subcritical water reactor (also called a subcritical treatment device or subcritical device) is used.

[0033] The woody biomaterial is sent to a woody biopellet production device 6, which produces woody biopellets 7. The woody biopellet production device 6 produces woody biopellets 7 using the woody biomaterial according to a known method.

[0034] The wood biopellets produced are sometimes called torrefaction pellets.

[0035] The woody biopellets 7 are transported by transport means 8, such as a transport vehicle, to a silo 11 of the biogas production device 3 and stored therein.

[0036] The biogas production device 3 is equipped with a silo 11, a superheated steam gasifier 12 (hereinafter referred to as the gasifier 12), a bag filter 13, a buffer tank 14, and a gas engine 15. Although not shown in the figure, a condenser and a cyclone may also be provided.

[0037] A superheated steam generator 16 is attached to the gasification furnace 12, and a generator 17 is connected to the gas engine 15. A belt conveyor 18 is disposed between the silo 11 and the gasification furnace 12, and a char discharge device 19 is disposed below the gasification furnace 12, through which char 20 is discharged from the gasification furnace 12 and used as fuel 21 for the superheated steam generator 16.

[0038] A hydrogen concentration detector can be disposed inside the gasification furnace 12 to constantly detect and monitor the hydrogen concentration inside the gasification furnace 12. A commercially available hydrogen concentration detector can be used.

[0039] The wood biopellets 7 stored in the silo 11 are transported to the gas furnace 12, where they are gasified using superheated steam from the superheated steam generator 16 to produce wood biogas. The wood biogas produced in this process is subjected to a subcritical water reaction process, which, due to the characteristics of the wood biopellets formed, turns it into high-energy wood biogas with a high carbon content, as will be described later. The gasifier 12 produces 22 even more highly energized wood biogas.

[0040] As will be described later, by applying an improved wood gas production method to the formed wood biopellets, in addition to the previously mentioned high energy content, the gas furnace 12 can produce 22 even more highly energized wood biogas.

[0041] The electricity generated by the generator 17 is normally transmitted to a power transmission system after being adjusted in voltage, current, and frequency using a well-known power transmission device.

[0042] As described above, the woody biogas generation system 100 shown in FIG. 1 is composed of a first-stage component that generates woody biopellets through subcritical water reaction treatment using the biopellet production device 2, and a second-stage component that generates woody biogas from the highly-energized woody biopellets using the biogas production device 3.

[0043] FIG. 2 is a diagram showing the configuration of a wood biopellet manufacturing apparatus according to an embodiment of the present invention.

[0044] In Fig. 2, the hydrothermal reaction treatment system includes a subcritical water reaction treatment device, and the hydrothermal reaction treatment system is composed of a treatment material input system, a subcritical water reaction device including a heat source for supplying heat, a hydrothermal reaction residue treatment system, and a control device. A general hydrothermal reaction treatment system itself has a well-known configuration.

[0045] In this embodiment of the present invention, the subcritical water reaction apparatus 5 includes a pressure vessel (also called a reactor) 101. The pressure vessel 101 is connected to a boiler 102 used as a heat source for supplying steam using an aqueous medium, and is also connected to a processing material input system, a methane recovery system, a hydrothermal reaction treatment system, and a torrefaction treatment system. A control device 105 is provided to control the temperature, pressure, and treatment time within the pressure vessel.

[0046] The pressure vessel 101 is composed of an outer cylindrical vessel (also referred to as an outer jacket) 111 and an inner cylindrical vessel (also referred to as an inner jacket) 112 arranged on the inner wall of the outer cylindrical vessel 111 with a space therebetween, and an agitator 113 is provided in the space (inner space) 106 within the inner cylindrical vessel.

[0047] The pressure vessel 101 is provided with closure lids 114 and 115 at both ends, and one of the lids 115 is provided with a drive motor 116 on its side. The drive motor 116 is connected to an agitator 113 having rotating blades.

[0048] An outer temperature sensor and an outer pressure sensor 121 are provided to measure the temperature and pressure in the space (outer space) 107 between the outer cylindrical container 111 and the inner cylindrical container 112, an inner temperature sensor and an inner pressure sensor 122 to measure the temperature and pressure in the space (inner space) 106 of the inner cylindrical container 112, and a moisture sensor 123 to measure the moisture in the space of the inner cylindrical container 112. These sensors measure the temperature and pressure in the inner space 106 and the moisture in the inner space 106 of the inner cylindrical container 112, and the respective measured values ​​are transmitted as data signals to the control device 105 via electronic circuits. These signal data are recorded in the recording means of the control device 105. The measured moisture content is used to set control data for the torrefaction treatment time.

[0049] The pressure vessel 101 is equipped with a steam discharge pipe 118 connected to the inner cylindrical vessel 112, and a discharge control valve 119 is provided on the steam discharge pipe 118. This configuration allows water vapor in the inner space to be discharged to the outside. The pressure vessel 101 is equipped with an input hopper 125 connected to the inner cylindrical vessel 112, and an outlet having an outlet pipe 126 connected to the inner cylindrical vessel 112. The outlet pipe 126 is provided with an outlet discharge control valve 120. This configuration allows the torrefied material produced by the hydrothermal reaction treatment to be recovered to the outside, i.e., to a torrefied material recovery device.

[0050] The crusher 103 receives the collected raw material 131 to be processed, crushes the raw material 131 to be processed, and feeds the powdered raw material into the feed hopper 125. The feed hopper 125 is provided with a control valve, and the feeding of the raw material 131 to be processed, the subsequent processing, and the temperature adjustment to be adopted are controlled by the control device 105.

[0051] The crushing operation of the crusher 103 is controlled by a control device 105 connected by an electronic circuit.

[0052] The type of raw material 131 to be processed (wood material 1 in FIG. 1) is identified when it is collected. In many cases, the type of raw material to be processed is identified by the raw material processor. By attaching a photographing device (not shown) near the input hopper 125, comparing the image with a reference image, and providing a means (not shown) for identifying the type of raw material to be processed, the type of raw material to be processed can be automatically identified. The identification data is input to the control device 105.

[0053] The boiler 102 includes a steam supply line 133 that supplies the generated steam to the pressure vessel 101. A superheated steam generator 140 is provided in the steam supply line 133, and superheats the generated steam and supplies it to the pressure vessel 101.

[0054] The steam supply line 133 branches into a branch line 134 that supplies superheated steam into the space between the outer cylindrical vessel 111 and the inner cylindrical vessel 112, and a branch line 135 that supplies superheated steam into the space inside the inner cylindrical vessel 112, and control valves 136 and 137 are installed on each branch line. The control valves 136 and 137 are connected to the control device 105, and their opening and closing are controlled and adjusted by the control device 105. The superheated steam is supplied to the space between the outer cylindrical vessel 111 and the inner cylindrical vessel 112 and / or the space inside the inner cylindrical vessel 112. By providing the superheated steam generator 140, the internal temperature, i.e., the hydrothermal reaction treatment temperature, can be increased regardless of the pressure inside the inner cylindrical vessel.

[0055] The subcritical water reaction apparatus 5 is composed of a pressure vessel equipped with an inlet for the raw material to be treated, a mechanism for making the hydrothermal reaction uniform, and an outlet for removing the semi-carbonized powder produced after the hydrothermal reaction treatment, a heat source for the hydrothermal reaction treatment and heat treatment, and a control device for controlling the hydrothermal reaction treatment and heat treatment, and produces semi-carbonized material by hydrothermal reaction treatment and heat treatment of wood material.

[0056] The pressure vessel is composed of an outer cylindrical vessel and an inner cylindrical vessel, and an inner space within the inner cylindrical vessel and an outer space between the inner cylindrical vessel and the outer cylindrical vessel are defined by the inner cylindrical vessel.

[0057] The control means sets the hydrothermal reaction temperature of the subcritical reaction range of water under a predetermined pressure in the hydrolysis treatment area, and the wood is hydrolyzed in the hydrolysis treatment area to produce a hydrolyzed substance, i.e., semi-carbonized wood as a treatment result.

[0058] For example, water vapor is introduced into the inner space, and a hydrothermal reaction temperature in the subcritical reaction range of water is adopted. A hydrothermal reaction pressure is within 2.5 MPa, typically within 0.3 to 3.5 MPa, and a hydrothermal reaction zone is formed, controlled for an appropriately set hydrothermal reaction treatment time, and wood material is hydrolyzed to produce a semi-carbonized powder, which is a powdered hydrolysis treatment substance.

[0059] The introduction of water vapor into the inner space is stopped, and the water vapor in the inner space is discharged to the outside.

[0060] In the drying and semi-carbonization treatment area, a semi-carbonized powder treatment temperature obtained from the type of raw material to be treated and the calorific value multiple is set under a predetermined pressure, and a semi-carbonized powder material having a predetermined calorific value relative to the calorific value of the wood chips and semi-carbonized using a hydrothermal reaction treatment is produced from the hydrolysis treatment material.

[0061] A torrefaction treatment zone is formed within the outer space, where the carbonization temperature is within the range of 150 to 220°C and the treatment time is controlled, to form torrefied pellets from the hydrolysis-treated material through a hydrothermal reaction process, typically torrefied pellets using a hydrothermal reaction process with a high calorific value. The torrefied pellets are dried, torrefied, and powdered hydrothermal reaction solids, which are torrefied. A portion of the torrefied pellets may be used for other purposes.

[0062] Wood chips with a moisture content of 35-50% and a calorific value of 3,300 kcal / kg are widely known. A lower calorific value of 3,040 kcal / kg has been reported. In this invention, wood chips with a calorific value of 3,300 kcal / kg are used as the reference wood chips when calculating the calorific value multiple. The inventors' analysis also confirmed that semi-carbonized wood chips have a calorific value of 3,300 kcal / kg.

[0063] According to experiments conducted by the inventors, it has been confirmed that the provision of a torrefaction pellet forming system makes it possible to produce torrefied wood chips that have a calorific value 1.25 times that of 3,300 kcal / kg. The carbon content of the elemental composition of wood chips, which is about 50%, increases to over 60% in the torrefied wood chips that have been hydrothermally treated, resulting in a high energy content.

[0064] A torrefaction and powder treatment region can be formed by controlling the treatment time within the torrefaction temperature range of 150 to 220°C.

[0065] When the powdery particulate semi-carbonized material is obtained, a semi-carbonized pellet based on a hydrothermal reaction can be formed, which is mainly composed of the semi-carbonized material described above and is an aggregate of the powdery particulate semi-carbonized material after hydrothermal reaction semi-carbonization.

[0066] The semi-carbonized powder after the hydrothermal reaction is recovered in a semi-carbonized powder recovery device 141, and the harmful substances are rendered harmless and reduced in volume 142.

[0067] This achieves the following: - High calorific value resource: Production of semi-carbonized powder with a calorific value multiple of 1.25, preferably 1.5 or more, relative to the calorific value of wood chips. - Reduction of carbon dioxide, dioxins, and odors.

[0068] In this embodiment, a subcritical water reaction apparatus 5 is used.

[0069] The pressure vessel is composed of an outer cylindrical vessel and an inner cylindrical vessel, and the inner space within the inner cylindrical vessel and the outer space formed between the inner and outer cylindrical vessels are partitioned by the inner cylindrical vessel. A first heating means is provided in the inner space to introduce steam and directly heat the inner space, and a second heating means is provided to directly heat the outer space and indirectly heat the inner space. The first heating means makes it possible to form a hydrolysis treatment zone in the inner space where a hydrothermal reaction by hydrolysis is carried out at hydrothermal reaction pressure, and the second heating means makes it possible to form a drying / semi-carbonization treatment zone in the inner space under a predetermined pressure.

[0070] Furthermore, a system is constructed which includes a subcritical water reactor 5 using a pressure vessel with a double-pipe configuration, a hydrothermal reaction treatment and semi-carbonization powder treatment system 6, and the subcritical water reactor 5, and which uses the subcritical water reactor 5 as a heating means, i.e., a heat source such as a boiler.

[0071] FIG. 3 is a diagram showing the configuration of another subcritical water reaction apparatus according to an embodiment of the present invention.

[0072] The configuration of the subcritical water reaction apparatus 5 is substantially the same as the configuration of the subcritical water reaction apparatus shown in FIG.

[0073] 3, a heater 117 is provided in an external space 107, and a heating power supply 102A is provided in parallel with the boiler 102. The heating power supply 102A is connected to a control device 105 by an electric circuit and is controlled to be turned on and off.

[0074] The heater 117 is electrically heated by the supply of electricity from the heating power supply 102A.

[0075] 2 in that the outer space 107 is heated by a heat medium from a heater 117 instead of by steam heat. However, the same applies to the subcritical water reaction apparatus 5 in that the hydrothermal reaction produces torrefied pellets, typically dried torrefied hydrothermal pellets with a high calorific value.

[0076] Similar to the previous example, water vapor is introduced into the inner space to form a low-temperature hydrolysis treatment area controlled at a temperature within the subcritical reaction range of water and a hydrothermal reaction pressure of 3.5 MPa or less, typically 2.5 MPa or less, for an appropriately set hydrothermal reaction treatment time, whereby the wood is hydrolyzed to form a powdery hydrolyzed substance called a semi-carbonized product. However, what is different is that a low-temperature drying / semi-carbonization treatment area is formed within the outer space, where the semi-carbonization temperature is above the hydrothermal reaction temperature but not exceeding 220°C, and the treatment time is controlled, and this area is electrically heated and formed by heater 117 supplied with electricity from heating power source 102A.

[0077] FIG. 4 is a diagram showing the relationship between temperature X and weight loss rate Y on an XY coordinate system when the wood material is carbonized.

[0078] This figure shows the relationship between the processing temperature X and the weight change Y of the wood material, with the X and Y axes being coordinates. When the wood material is carbonized, the relationship between the temperature X and the weight loss rate Y is represented by an S-shaped curve on the X and Y axes, which can be divided into three sections: the shoulder of the gradual weight loss line that continues into the rapid weight loss, the S-shaped weight loss portion, and the end of the S-shaped curve where the rapid weight loss ends and the gradual weight loss begins.

[0079] When wood is subjected to heat treatment (dry distillation) in an airless atmosphere, its weight changes are known to follow a curve similar to the thermal decomposition curve (dry distillation curve) shown in Figure 4, which plots the relationship between the treatment temperature and the weight change of the wood. Here, the horizontal axis represents the heating temperature, and the vertical axis represents the weight percentage of the remaining solid (residual carbon) relative to the original wood. The decrease in residual carbon content occurs most rapidly around 250°C and continues slowly even at temperatures above 400°C, ultimately resulting in a charred product with a weight of about one-third to one-quarter of the original weight. Here, the shoulder of the gradual weight loss line, continuing into the rapid weight loss section, is referred to as Region (1), the portion of the S-shaped weight loss curve where the weight rapidly decreases is referred to as Region (2), and the portion at the end of the gradual weight loss line and the S-shaped weight loss section is referred to as Region (3).

[0080] The International Energy Agency (IEA) defines "torrefaction" as "heat treatment carried out at 250 to 320°C in a reduced oxygen atmosphere," and conventionally, semi-carbide formation was carried out at temperatures in the (2) region.

[0081] Figure 5 is a diagram illustrating the coagulation, fixation, and semi-carbonization process of multiple hemicellulose-based monosaccharides into the lower molecular weight cellulose components and lignin components that form woody biomaterials, on an XY coordinate system.

[0082] The low-temperature semi-carbonization treatment associated with the subcritical water reaction treatment will now be described.

[0083] Low-temperature semi-carbonization is performed in the (1) region. Semi-carbonization in the (1) region is possible by performing subcritical water reaction treatment.

[0084] In FIG. 5, in process (1), a hydrolysis process (subcritical water reaction process) is carried out using superheated steam to break down wood into smaller molecules.

[0085] The temperature used is the subcritical water reaction temperature, preferably 230 to 240° C., although the temperature is not limited to this.

[0086] In process (2), the wood is semi-carbonized at a low temperature.

[0087] By performing the process (1) → (2), semi-carbonization is performed at a low temperature.

[0088] First stage: Temperature treatment at 150-220°C. The wood is heated to this temperature and maintained at this temperature to liquefy the hemicellulose components. Multiple monosaccharides of the liquefied hemicellulose system are produced and exist between the degraded cellulose components and degraded lignin components.

[0089] Second stage: temperature treatment at 110 to 130°C. By reducing the temperature to this temperature, the liquefied hemicellulose-based monosaccharides are solidified and fixed to the low-molecular-weight cellulose components and lignin components.

[0090] These two processes result in semi-carbonized woody bio-material.

[0091] Semi-carbonized wood biomaterial: The main components are low molecular weight cellulose components, low molecular weight lignin components, and multiple hemicellulose-based monosaccharides that have solidified and adhered to these cellulose and lignin components.

[0092] In process (3), wood pellets are produced.

[0093] Wood pellets are produced from the resulting semi-carbonized wood biomaterial.

[0094] The semi-carbonization process is carried out at a temperature of 150 to 220°C, which is lower than the temperature range used in conventional semi-carbonization processes, and therefore semi-carbonized wood material that retains 90 to 95% of the heat generated by the wood material before the process can be obtained in an extremely short time.

[0095] Figure 6 is a micrograph (1) of the product of wood material processed according to Figure 5. Figure 7 is a micrograph (2) of the product of wood material processed according to Figure 5. Figure 8 is a micrograph (3) (4) of the product of wood material processed according to Figure 5. Micrograph (1) was taken at a magnification of 35x. The upper photo of micrograph (1) is a photo of the wood material (wood chips) that was the treated material, and the lower photo is a photo of the wood biopellets obtained in this example.

[0096] Micrograph (2) was taken at a magnification of 140x. The top photo of micrograph (2) is a photo of wood material (wood chips), and the bottom photo is a photo of wood biopellets obtained in this example. The wood biomaterial was produced by torrefying the wood biomaterial at a temperature typically within 190°C (the same applies below). Micrograph (3) is a photo of wood biopellets obtained in this example at a magnification of 500x.

[0097] Micrograph (4) is a photograph of the wood biopellets obtained in this example taken at a magnification of 1000x.

[0098] As shown in the photograph of the wood material (wood chips), the wood material (wood chips) is composed mainly of cellulose components, hemicellulose components, and lignin components, which are connected together in a polymeric state and are formed in an orderly manner without any voids.

[0099] In photos (2) to (4), the wood biopellets exhibit a discontinuous state of degraded cellulose and degraded lignin components, with multiple coagulated and fixed hemicellulose-based monosaccharides present between the degraded cellulose and lignin components. This state is more clearly visible at magnifications of 140x (FIG. 7), 500x (top photo in FIG. 8), and 1000x (bottom photo in FIG. 8) than at magnifications of 35x (FIG. 6).

[0100] In the case of wood biopellets, they are black overall, indicating that they have been semi-carbonized.

[0101] Thus, the micrograph shows a woody biomaterial that is mainly composed of cellulose, hemicellulose, and lignin components, with low-molecular-weight cellulose and lignin components intermittently present, and with multiple coagulated and fixed hemicellulose-based monosaccharides present between the low-molecular-weight cellulose and lignin components.

[0102] Therefore, according to the present invention, a semi-carbonized wood biomaterial is provided, whose main components are low-molecular-weight cellulose components, low-molecular-weight lignin components, and multiple hemicellulose-based monosaccharides that have solidified and adhered to these cellulose and lignin components.

[0103] FIG. 9 is a diagram illustrating the optimum semi-carbonization process.

[0104] When woody biomaterial that has been subjected to subcritical water reaction treatment is semi-carbonized, the amount of carbon (C) produced varies depending on the temperature.

[0105] FIG. 9 shows an optimum range in which a large amount of carbon C can be obtained in a temperature range of 180 to 200° C., a low temperature range in which an increased amount of carbon C can be obtained in a temperature range of 150 to 180° C., which is practical but the amount of carbon C is small, and a high temperature range in which an increased amount of carbon C can be obtained in a temperature range of 180 to 220° C., which is practical but the amount of carbon C is small.

[0106] The semi-carbonization treatment is carried out at an appropriate temperature selected within the temperature range of 150 to 220°C.

[0107] For example, 190° C. is selected to produce woody biomaterial with a calorific value of 5330 kcal / kg.

[0108] In the temperature range of 150 to 180°C or 180 to 220°C, although the thermal energy is less than the maximum calorific value of 5,330 kcal / kg, it is possible to produce woody biomaterial with a calorific value of, for example, 4,000 kcal / kg, which is greater than the 3,300 kcal / kg of wood chips.

[0109] FIG. 10 shows the produced wood biopellets.

[0110] FIG. 10(1) shows a single wood biopellet, and FIG. 10(2) shows an aggregated wood biopellet.

[0111] Wood biopellets are produced from wood biomaterials.

[0112] In FIG. 10(1), the produced wood biopellets are cylindrical with a diameter of 6 mm and made of powdered semi-carbonized material.

[0113] The characteristics of the torrefied woody biomaterial are shown in FIGS. 6 to 8. The torrefied woody biomaterial has a high calorific value of, for example, 5,330 kcal / kg, compared to the calorific value of 3,300 kcal / kg of typical wood chips.

[0114] FIG. 11 is a diagram showing the process for producing a woody biofuel body.

[0115] FIG. 11(1) is a diagram showing the process of producing a woody biofuel body, and FIG. 11(2) is a partially enlarged view of the solid body.

[0116] The apparatus used is a semi-carbonized carbonized wood biomaterial, which is provided with a subcritical water reaction treatment device and is characterized in that the subcritical water reaction treatment device is used to produce semi-carbonized carbonized wood biomaterial, the main components of which are cellulose components degraded from wood material, lignin components degraded from wood material, and multiple hemicellulose-based monosaccharides that are solidified and fixed to these cellulose components and lignin components.

[0117] The subcritical water reaction treatment of wood material 1 using the subcritical water reaction treatment device 5 shown in FIG. 1 maintains the wood chip shape of the wood material 1, reduces the external dimensions, and forms easily crushable solids 51 and powder 52.

[0118] As shown in Figure 11 (2), the solid 51 consists of a hard layer 61 and a soft layer 62, and these layers contain multiple hemicellulose-based monosaccharides due to hemicellulose saccharification 63, and voids 64 due to hot water treatment with subcritical water were observed.

[0119] The powder 52 is aggregated 53 and wood biopellets 7 are produced by the wood biopellet production device 6 as described above.

[0120] In producing the wood biopellets 7, a powder formed by pulverizing a part of the solid body 51 may be mixed with the powder 52 and used.

[0121] The solid bodies 51 are aggregated 54 to form solid fuel bodies 55 .

[0122] The woody biopellets 7 and the solid fuel bodies 55 are mixed to form woody biofuel bodies 56 , which are stored in the silo 11 of the gasification furnace 12 and then fed into the gasification furnace 12 .

[0123] A wood biofuel production device using a semi-carbonized carbonization production device is constructed, characterized in that a solid semi-carbonized carbonized material and a powder semi-carbonized carbonized material are produced from the wood material using the subcritical water reaction treatment device, and then mixed to produce wood biofuel.

[0124] FIG. 12 is an explanatory diagram of the gasification process of wood biopellets.

[0125] In Figure 4, we show that wood material is usually expressed as an S-shaped curve on the XY coordinate system, where the temperature X and the weight loss rate Y are divided into three sections: the shoulder part of the gradual weight loss line that continues into the part where the weight suddenly decreases, the S-shaped curve where the weight suddenly decreases, and the end part of the S-shaped curve where the weight suddenly decreases and the gradual decrease line.

[0126] As mentioned above, the carbon content of the elemental composition of wood chips is about 50%, but in the semi-carbonized material that is hydrothermally treated, it becomes 60% or more, resulting in high energy content.

[0127] After steps (1) to (3) shown in Figure 5, the gasification process of the wood biopellets (step (4)) and the power generation process (step (5)) are carried out. Steps (1) to (5) complete the gasification process of the wood biopellets.

[0128] By forming a semi-carbonized wood biomaterial from the shoulder portion, which is mainly composed of low molecular weight cellulose components, low molecular weight lignin components, and multiple hemicellulose-based monosaccharides that have solidified and adhered to these cellulose and lignin components, it is possible to obtain a semi-carbonized wood biomaterial that retains 90 to 95% of the heat generation value before processing.

[0129] The temperature is adjusted to the shoulder of the S-shaped curve, and for a predetermined time and under a predetermined pressure, the hemicellulose components that form the woody biomaterial are liquefied and solidified, and fixed to the other components that form the woody biomaterial, namely, low-molecular-weight cellulose components and lignin components, to form a woody biomaterial mainly composed of multiple fixed hemicellulose-based monosaccharides, low-molecular-weight cellulose components, and lignin components, and the woody biomaterial is then semi-carbonized. Woody biopellets are produced from the pretreated woody biomaterial using a woody biopellet manufacturing device, and the woody biopellets are fed into the biogasification furnace and woody biogasification is carried out for a predetermined time and under a predetermined pressure at a temperature set in the temperature range of 230 to 600°C, which is set at the part of the S-shaped curve where the weight suddenly decreases.

[0130] FIG. 13 is an XY coordinate diagram illustrating the temperature range employed in this embodiment.

[0131] In FIG. 13, the first and second stage processes are shown.

[0132] The first stage treatment refers to the treatment area where the torrefaction of the present invention takes place.

[0133] The second stage treatment is a gasification treatment, i.e., a gasification treatment region by superheated steam reaction. On the XY axis coordinate, region (1) is the first stage treatment, and regions (2) and (3) are the second stage treatment.

[0134] The first stage treatment consists of a temperature range of 150 to 220°C and a temperature range of 110 to 130°C, and in the first stage treatment, the torrefaction of the present invention is carried out.

[0135] In the temperature range of 150 to 220°C, hemicellulose components are saccharified to produce multiple hemicellulose-based monosaccharides.

[0136] This temperature range is also the temperature range in which hemicellulose components liquefy and volatilize, with most of them liquefying.

[0137] The temperature range of 110 to 130°C is the temperature range in which multiple hemicellulose-based monosaccharides solidify and solidify.

[0138] The treatment (2) in FIG. 5 is carried out in the temperature range of 150 to 220°C in the first stage treatment and in the temperature range of 110 to 130°C.

[0139] The treatment (4) in FIG. 12 is carried out in the temperature range of 230 to 600° C. in the second stage treatment.

[0140] As an example of conventional torrefaction, it has been proposed to perform torrefaction at a temperature of 200 to 320°C.

[0141] Although the temperature range for the torrefaction of the present invention is partly covered at 200 to 220°C, the present invention differs in that the temperature range for the torrefaction of the present invention is set after the process (1) in Fig. 5 is carried out. That is, the present invention is characterized by having a subcritical water reaction process to set the temperature range for the torrefaction of the present invention.

[0142] (2) Regarding the selection of the temperature range: A temperature range of 230 to 450°C is selected.

[0143] (3) Regarding the selection of the temperature range: A temperature range of 450 to 600°C is selected.

[0144] FIG. 14 is a diagram showing steps of a woody biogas production method according to an embodiment of the present invention.

[0145] First-stage treatment: Pretreatment using subcritical water reaction: The raw wood material is fed into a subcritical water reaction treatment device. The raw wood material is treated with a subcritical water reaction to reduce the molecular weight of the material. Pretreatment is then carried out on the wood biomaterial after the subcritical water reaction treatment.

[0146] Semi-carbonization process: The hemicellulose components are liquefied to generate multiple hemicellulose-based monosaccharides, and the temperature is adjusted to 110-130°C to solidify and fix the multiple hemicellulose-based monosaccharides to the low-molecular-weight cellulose and lignin components.

[0147] This fixation allows the wood to retain multiple hemicellulose-based monosaccharides as a heat source. Through these processes, the wood is semi-carbonized to produce semi-carbonized wood biomaterial.

[0148] Wood biopellets are then produced.

[0149] Second stage treatment: Production of wood biogas The wood biopellets produced in the first stage are fed into a wood biogasification furnace. The wood biopellets are gasified while the hydrogen concentration is kept low.

[0150] Gas temperature: 230 to 600°C Treatment time: Predetermined time: 15 to 60 minutes

[0151] 100...wood biogas generation system, 1...wood material (organic matter from forest residues, processed raw material), 2...biopellet manufacturing equipment, 3...biogas production equipment, 4...superheated steam generator, 5...subcritical water reaction equipment, 6...wood biopellet manufacturing equipment, 7...wood biopellets (torrefaction pellets), 8...transport means, 11...silo, 12...superheated steam gasifier (referred to as gasifier), 13...bag filter, 14...buffer tank, 15...gas engine, 16...superheated steam generator, 17...generator, 19...charcoal discharge device, 20...charcoal (charcoal including wood biomaterial), 21...fuel, 22...generation of wood biogas, 51...solid body, 52...powder, 55...solid fuel body, 56...wood biofuel body.

Claims

1. A wood biogas generation system that produces semi-carbonized biomass woody material (hereinafter referred to as the biomass woody material) from raw wood material, produces semi-carbonized biomass woody pellets (hereinafter referred to as the biomass woody pellets) from the biomass woody material, and gasifies the biomass woody pellets in a gasifier, is equipped with a subcritical water reaction treatment device, a biomass woody pellet generator, and a biomass woody gasifier, and the relationship between temperature X and weight loss rate Y in the subcritical water reaction treatment device is expressed by an S-shaped curve on the XY axis coordinate system, which is divided into three sections: the part where temperature X is 220°C or less and the shoulder of the gradual weight loss line continues to the part where weight decreases rapidly, the part where weight decreases rapidly on the S-shaped curve, and the part where weight decreases rapidly and the end of the gradual S-shaped curve where weight decreases rapidly. The subcritical water reaction treatment apparatus has a first treatment region where the temperature is heated to a temperature of 220°C or less and maintained for 15 to 60 minutes at the shoulder of the S-shaped curve, and a second temperature region where the temperature is adjusted to 130°C or less, and the apparatus treats the woody material at a treatment temperature of 150 to 220°C for 15 to 60 minutes to form low-molecular-weight cellulose components and low-molecular-weight lignin components from the cellulose and lignin components of the woody material, and liquefies hemicellulose components from the hemicellulose components, and the second treatment at a temperature of 110 to 130°C forms a woody biomaterial that retains 90% of the calorific value of the calorific value retained by the woody material as a raw material for treatment, the woody biomaterial being mainly composed of hemicellulose components that have solidified and adhered to the cellulose and lignin components (hereinafter referred to as the 90% calorific value woody biomaterial); the woody biopellet production apparatus produces woody biopellets from the 90% calorific value woody biomaterial; The wood biogas generation system is characterized in that the wood biogasification furnace gasifies the wood biopellets at a processing temperature of 230 to 600°C for a processing time of 15 to 60 minutes.

2. A woody biogas generation system as described in claim 1, characterized in that the subcritical water reaction treatment device generates semi-carbonized solid matter and semi-carbonized powder, and these semi-carbonized solid matter are mixed together to form woody biopellets.

3. A power generation device using a woody biogas generation system as described in claim 1, characterized in that the gasification furnace is equipped with a second superheated steam generator as a heat source for gasification, and woody biogas is generated from the woody biopellets by hydrolysis treatment using second superheated steam at a temperature of 230 to 600°C, which is higher than the temperature of the first superheated steam input into the subcritical water reaction treatment device, and the woody biogas is input into the gasification furnace, and a gas engine connected to a generator is connected to the power generation device.

4. In the wood biomaterial manufacturing device used in the wood biogas generation system described in claim 1, the subcritical water reaction treatment device is equipped with a superheated steam generator as a heat source for the subcritical water reaction treatment and semi-carbonization treatment, and the relationship between temperature X and weight loss rate Y is expressed by an S-curve on the XY coordinate system, which is divided into three sections: the part where temperature X is below 220°C and continues to the part where the weight decreases sharply at the shoulder of the gradual weight loss line, the part where the weight decreases sharply on the S-curve, and the part where the weight decrease ends and the exit of the S-curve of the gradual weight decrease line; and the temperature at the shoulder of the S-curve is heated to a temperature below 220°C in the first step, and the temperature is increased to 15 to 25°C. This woody biomaterial manufacturing device is used in a woody biogas generation system and is characterized by having a treatment area where the temperature is maintained for 60 minutes and a second temperature area where the temperature is adjusted to 130°C or less, and by forming low-molecular-weight cellulose components and low-molecular-weight lignin components from the cellulose and lignin components of woody material, and liquefying hemicellulose components from the hemicellulose components, at a treatment temperature of 150 to 220°C for a treatment time of 15 to 60 minutes, and by performing a second-stage temperature treatment at 110 to 130°C, forming woody biomaterial with 90% of the calorific value, mainly consisting of hemicellulose components that have solidified and fixed to the cellulose and lignin components.

5. A woody biogas generation method that produces semi-carbonized woody biomaterial (hereinafter referred to as "the woody biomaterial") from raw woody material, produces semi-carbonized woody biopellets (hereinafter referred to as "the woody biopellets") from the woody biomaterial, and gasifies the biopellets in a gasifier, comprising a subcritical water reaction treatment device, a woody biopellet production device, and a woody biogasification furnace, wherein the subcritical water reaction treatment device expresses the relationship between temperature X and weight loss rate Y on an XY coordinate system as an S-shaped curve divided into three sections: a portion where temperature X is 220°C or less and continues to the portion of rapid weight loss at the shoulder of the gradual weight loss line, a portion of rapid weight loss on the S-shaped curve, and a portion where the rapid weight loss ends and the outlet of the S-shaped curve of the gradual weight loss line; and the shoulder temperature of the S-shaped curve has a first temperature range of 220°C or less and a second temperature range where the temperature is adjusted to a temperature of 130°C or less. the subcritical water reaction treatment apparatus has a first-stage treatment zone where the temperature is raised to 220°C or lower and maintained at that temperature for 15 to 60 minutes, and a second-stage temperature zone where the temperature is adjusted to 130°C or lower; the cellulose and lignin components of the wood material are degraded into lower molecular weight cellulose components and lower molecular weight lignin components, and the hemicellulose components are liquefied into hemicellulose components, at a treatment temperature of 150 to 220°C for a treatment time of 15 to 60 minutes; the second-stage treatment at a temperature of 110 to 130°C produces a woody biomaterial with 90% of the calorific value, mainly composed of hemicellulose components that have solidified and adhered to the cellulose and lignin components; the woody biopellets are produced by the woody biopellet production apparatus from the woody biomaterial with 90% of the calorific value; and the gasification furnace gasifies the woody biopellets at a treatment temperature of 230 to 600°C for a treatment time of 15 to 60 minutes.

6. A woody biogas generation method as described in claim 5, characterized in that the subcritical water reaction treatment device generates semi-carbonized solid matter and semi-carbonized powder, which are then mixed together to form woody biopellets.

7. A wood biogas generation method according to claim 5, wherein the gasification furnace is equipped with a second superheated steam generator as a heat source for gasification, and second superheated steam at a temperature of 230 to 600°C, which is higher than the temperature of the first superheated steam fed into the subcritical water reaction treatment device, is used to generate wood biogas from the wood biopellets through hydrolysis treatment using superheated steam.

8. In the wood biomaterial production method using a wood biomaterial production device used in a wood biogas generation system described in claim 5, the subcritical water reaction treatment device is equipped with a superheated steam generator as a heat source for the subcritical water reaction treatment and semi-carbonization treatment, and the relationship between temperature X and weight loss rate Y is expressed as an S-curve divided into three sections on the XY coordinate system: the part where temperature X is 220°C or less and the part continuing to the part where the weight decreases sharply at the shoulder of the gradual weight loss line, the part where the weight decreases sharply on the S-curve, and the part where the weight decrease ends and the end of the S-curve of the gradual decrease line; and the temperature at the shoulder of the S-curve is heated to a temperature of 220°C or less in the first stage, and the temperature is increased to 15 to 60°C. and a second temperature zone for adjusting the temperature to 130°C or less, wherein the woody biomaterial is treated at a temperature of 150-220°C for 15-60 minutes to form low molecular weight cellulose components and low molecular weight lignin components from the cellulose and lignin components of the woody material, and liquefied hemicellulose components from the hemicellulose components, and the second temperature zone for adjusting the temperature to 130°C or less is treated at a temperature of 110-130°C to form woody biomaterial with 90% of the calorific value, mainly composed of hemicellulose components that have solidified and adhered to the cellulose and lignin components.

9. A semi-carbonized charred wood biomaterial, in which raw wood is treated with a subcritical water reaction at a temperature of 150-220°C for 15-60 minutes, to form low-molecular-weight cellulose components and low-molecular-weight lignin components from the cellulose and lignin components of the wood, and liquefy hemicellulose components from the hemicellulose components, which are then solidified and fixed to the cellulose and lignin components at a temperature of 110-130°C to form the wood biomaterial, and which contains the wood biomaterial as the main component and retains 90% of the calorific value of the raw wood.

10. Semi-carbonized wood biopellets formed from semi-carbonized wood biomaterial, in which raw wood is treated with subcritical water at a temperature of 150-220°C for 15-60 minutes to form low-molecular-weight cellulose components and low-molecular-weight lignin components from the cellulose and lignin components of the wood, and liquefy hemicellulose components from the hemicellulose components, and the hemicellulose components are solidified and fixed to the cellulose and lignin components through a temperature treatment of 110-130°C, and the wood material containing the wood biomaterial as a main component retains 90% of the calorific value of the raw wood.

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