Charcoal production method and charcoal production facility

Abstract

To achieve reduction of waste and effective utilization of waste as a CO2 absorption and fixation material.SOLUTION: A charcoal production method for producing charcoal from woody waste generated at a construction site, comprising a recovery step of recovering the woody waste into a charcoal production facility, and a carbonization step of carbonizing the woody waste in the charcoal production facility.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for producing charcoal and charcoal production equipment.

Background Art

[0002] Conventionally, charcoal (so-called biochar), which is a carbide made from biological resources and is said to be effective in activating organisms and improving the environment, has been known. For example, Patent Document 1 discloses that by mixing biochar as a material for a cement composition, it is possible to reduce the amount of carbon dioxide (CO2) emitted during the production of the cement composition.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, at construction sites including demolition work and new construction work (hereinafter, construction sites), a large amount of used wooden materials (for example, wooden formwork) are generated, and these wooden formwork and the like are not reused and are often discarded as wooden waste. From the perspective of resource circulation, the reuse of such wooden waste is required, but specific reuse methods have not been studied.

[0005] The present invention has been made in view of such problems, and an object thereof is to reduce waste and effectively utilize the waste as a material for absorbing and fixing CO2.

Means for Solving the Problems

[0006] The main invention for achieving the above object is a charcoal manufacturing method for manufacturing charcoal from wood waste generated at a construction site, comprising a recovery step of recovering the wood waste into a charcoal manufacturing facility, and a carbonization step of carbonizing the wood waste in the charcoal manufacturing facility. The charcoal manufacturing method is characterized by having these steps.

[0007] Other features of the present invention will be clarified by the description in this specification and the attached drawings.

Effect of the Invention

[0008] According to the present invention, waste can be reduced and the waste can be effectively utilized as a CO2 absorption and fixation material.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0010] From the description in this specification and the attached drawings, at least the following matters become clear.

[0011] (Aspect 1) A charcoal manufacturing method for manufacturing charcoal from wood waste generated at a construction site, comprising a recovery step of recovering the wood waste into a charcoal manufacturing facility, and a carbonization step of carbonizing the wood waste in the charcoal manufacturing facility. The charcoal manufacturing method is characterized by having these steps.

[0012] According to the carbon manufacturing method of Aspect 1, by collecting the wood waste generated at the construction site and carbonizing it with carbon manufacturing equipment, carbon can be manufactured from the wood waste. Further, in the carbon manufacturing equipment, by heating the wood waste in an environment where it is not combined with oxygen as much as possible, carbon containing a large amount of carbon in a stable state can be manufactured. Thereby, waste can be reduced, and the waste can be effectively utilized as a CO2 absorption and fixation material.

[0013] (Aspect 2) The carbon manufacturing method according to Aspect 1, wherein the wood waste is generally surface-treated if it is, for example, formwork waste, and in the carbonization step, the wood waste may be carbonized in the surface-treated state.

[0014] According to the carbon manufacturing method of Aspect 2, carbon can be manufactured from the surface-treated wood waste, and waste can be effectively utilized.

[0015] (Aspect 3) The carbon manufacturing method according to Aspect 1 or Aspect 2, wherein the fuel used for heating in the carbonization is preferably wood waste.

[0016] According to the carbon manufacturing method of Aspect 3, waste can be effectively utilized (as fuel), and carbonization can be performed without using fossil fuels with a large amount of CO2 emissions.

[0017] (Aspect 4) The carbon manufacturing method according to any one of Aspects 1 to 3, wherein the carbonization preferably has a heating temperature of 350 °C or higher and a carbonization time of 4 hours or longer.

[0018] According to the carbon manufacturing method of Aspect 4, carbon can be surely generated.

[0019] (Aspect 5) The carbon manufacturing method according to any one of Aspects 1 to 4, wherein the carbonization step preferably has a secondary combustion step.

[0020] According to the carbon manufacturing method of Aspect 5, impurities contained in the smoke generated during the carbonization process can be removed.

[0021] (Aspect 6) The carbon manufacturing method according to any one of Aspects 1 to 5, wherein it is desirable that the carbon has a refractory carbon content of 50% or more.

[0022] According to the carbon manufacturing method of Aspect 6, stable carbon (difficult to decompose under natural conditions) can be produced.

[0023] (Aspect 7) The carbon manufacturing method according to any one of Aspects 1 to 6, having a pulverization treatment step of pulverizing the carbonized wood waste, and in the pulverization treatment step, it is desirable to perform pulverization so that the particle size range becomes 30 mm or less.

[0024] According to the carbon manufacturing method of Aspect 7, the carbon can be made into fine particles, making it easier to utilize effectively.

[0025] (Aspect 8) The carbon manufacturing method according to Aspect 7, wherein it is desirable to have a removal step of removing members other than carbon between the carbonization treatment step and the pulverization treatment step.

[0026] According to the carbon manufacturing method of Aspect 8, after carbonizing the wood waste, members other than carbon (for example, metal members such as nails) are removed, so it is easier to remove such members (hereinafter, nails, etc.) compared to before carbonization. Also, since nails and the like are removed before the pulverization treatment, nails and the like do not interfere in the pulverization treatment, and pulverization can be performed reliably.

[0027] (Aspect 9) The carbon manufacturing method according to any one of Aspects 1 to 8, wherein it is desirable that the wood waste is a formwork used when placing a cement composition.

[0028] According to the method for producing charcoal of Aspect 9, used formwork that is generated in large quantities at a construction site can be reused without being discarded.

[0029] (Aspect 10) A charcoal production facility for producing charcoal from wooden waste materials generated at a construction site, comprising: a housing net body in which the wooden waste materials are housed; an air supply layer provided below the housing net body; a covering body that covers the housing net body and the air supply layer; and an air inlet / outlet that penetrates the covering body and communicates the air supply layer with the outside air.

[0030] According to the charcoal production facility of Aspect 10, charcoal can be produced from wooden waste materials generated at a construction site. Further, in the charcoal production facility, by heating the wooden waste materials in an environment where they are combined with oxygen as little as possible, charcoal containing a large amount of carbon in a stable state can be produced. Thereby, waste can be reduced, and the waste can be effectively utilized as a material for absorbing and fixing CO2.

[0031] ===Embodiment=== <<Regarding the background of the invention>> At a construction site or the like, when placing concrete, a wooden formwork (for example, plywood) with a surface finish is often used. For example, in the case of reinforced concrete, a wooden formwork is formed into a framework, steel bars are incorporated inside the wooden formwork, and then concrete is placed. After the concrete hardens, the wooden formwork is demolded (removed).

[0032] By the way, since it is difficult to separate used wooden formworks with a surface finish, they are often discarded as industrial waste (wooden waste materials) after demolding (after use). From the perspective of resource recycling, a method for recycling such wooden waste materials is required, but specific recycling methods have not been studied.

[0033] Therefore, in the present embodiment, as described later, used wooden formworks (wooden waste materials) are collected and charcoal is generated in a charcoal production facility, thereby reducing waste and enabling the generated charcoal to be effectively utilized as a material for absorbing and fixing carbon dioxide (CO2).

[0034] Incidentally, biochar is known as an example of charcoal. Biochar is a solid obtained by carbonizing organic matter (so-called biomass) derived from organisms such as animals and plants (for example, trees). Specifically, it is charcoal produced by heating biomass at a temperature above 350°C under an oxygen concentration controlled at a non-combustion level (2019 improvement of the 2006 IPCC Guidelines for National Greenhouse Gas Inventories). The charcoal produced in this embodiment uses wood waste as a raw material.

[0035] <<Charcoal production equipment>> FIG. 1 is a front view of the carbonization furnace 10 of the charcoal production equipment 1 in this embodiment. FIG. 2 is a perspective view of the back side (rear side) of the carbonization furnace 10. In FIG. 1, a part of the cover body 11 is made transparent to show the cage 20 disposed inside the cover body 11. Further, in FIG. 2, the secondary combustion furnace 30 of the charcoal production equipment 1 and the like are also shown. FIG. 3 is a schematic perspective view of the cage 20.

[0036] As shown in FIGS. 1 to 3, the charcoal production equipment 1 of this embodiment includes a carbonization furnace 10, a cage 20, and a secondary combustion furnace 30.

[0037] Incidentally, the carbonization furnace 10 (including the cage 20) of this embodiment has three mutually intersecting directions (vertical direction, front-rear direction, and left-right direction). The vertical direction is the height direction (direction along the vertical direction) of the carbonization furnace 10, with the upper side in the vertical direction being "up" and the lower side in the vertical direction being "down". Further, the front-rear direction is the depth direction of the carbonization furnace 10, with the front side of the carbonization furnace 10 being "front" and the back side being "rear". Also, the left-right direction is the width direction of the carbonization furnace 10, with the right side being "right" and the left side being "left" when looking from the back side to the front in the front-rear direction.

[0038] <Carbonization furnace 10> The carbonization furnace 10 is a furnace for carbonizing (carbonization treatment) wood waste (in this embodiment, the used wooden formwork 3 (see FIG. 2)), and includes a cover body 11, an air inlet 12, and an exhaust port 13.

[0039] The covering body 11 is a metallic member (furnace) having a substantially cubic shape, and covers the periphery (front, rear, left, right side surfaces, and upper surface) of the cage 20 described later. Further, the lower end portion of the covering body 11 is open, and the cage 20 can be arranged at a predetermined position (inside the covering body 11) by lifting the covering body 11 upward using an elevator (lift) or the like. However, it is not limited to this, and for example, a door or the like for taking the cage 20 in and out may be provided on the side surface of the covering body 11.

[0040] The intake port 12 is an opening for taking in air (outside air) into the inside of the covering body 11, and is provided at the lower part of the front surface of the covering body 11. The intake port 12 is formed to penetrate the covering body 11, and communicates the inside of the covering body 11 (specifically, the air supply layer 22 of the cage 20) with the outside air. In the present embodiment, three intake ports 12 are provided at intervals in the left - right direction, but it is not limited to this. For example, two intake ports may be provided, or four or more intake ports may be provided.

[0041] Also, as shown in FIGS. 4A to 4C, by attaching lids 50A, 50B or a cylindrical body 60 to the intake port 12, the amount of air taken in from the intake port 12 can be adjusted. FIG. 4A is a view in which the lid 50A is attached to the intake port 12, FIG. 4B is a view in which the lid 50B is attached to the intake port 12, and FIG. 4C is a view in which the cylindrical body 60 is attached to the intake port 12.

[0042] In FIG. 4A, an opening 51a is formed in the central portion of the lid 50A attached to the intake port 12. The inner diameter d0 of the intake port 12 is, for example, 150 mm, while the opening diameter d1 of the opening 51a of the lid 50A is 100 mm (<d0). Therefore, by attaching the lid 50A, the amount of air taken into the inside of the covering body 11 is reduced. The lid 50A is also provided with a handle or the like for the operator to grip when removing it, but illustration thereof is omitted here (the same applies to the lid 50B).

[0043] Also, in FIG. 4B, an opening 51b is formed in the central portion of the lid 50B attached to the intake port 12. The opening diameter (d2) of the opening 51b of the lid 50B is, for example, 40 mm, which is smaller than the opening diameter (d1) of the lid 50A (d2 < d1 < d0). Therefore, when the lid 50B is attached, the amount of air taken into the inside of the cover 11 becomes even less compared to the case where the lid 50A is attached (FIG. 4A).

[0044] Note that a lid without an opening (not shown) may be attached to any intake port 12 so that air is not taken in from that intake port 12.

[0045] Also, in FIG. 4C, a cylindrical body 60 is attached to the intake port 12. By attaching the cylindrical body 60 in this way (furthermore, processing the tip of the cylindrical body 60 to be crushed into an elliptical shape, for example), the amount of air taken in from the intake port 12 can also be reduced, and combustion can be suppressed. Note that the cylindrical body 60 is attached in advance to the intake port 12 at a location where combustion is likely to occur in advance, while the lids (such as lids 50A and 50B) can be replaced according to the combustion situation.

[0046] The exhaust port 13 is a part that discharges the smoke generated when the carbonization process is performed in the carbonization furnace 10, and is provided at the lower part of the back surface (rear surface) of the cover 11. Also, the exhaust port 13 has an opening 13a that penetrates the cover 11. And the exhaust port 13 communicates the inside of the cover 11 with the outside air via a secondary combustion furnace 30 described later. In the present embodiment, two exhaust ports 13 are provided at intervals in the left - right direction, but this is not limiting. For example, one exhaust port may be provided, or three or more exhaust ports may be provided. Also, in the present embodiment, the opening 13a is formed on the upper surface of the exhaust port 13 and penetrates the cover 11, but this is not limiting. For example, it may be formed on the side surface (rear surface, etc.).

[0047] In addition, an exhaust pipe P is attached to the opening 13a of the exhaust port 13, and the exhaust pipe P is connected to the secondary combustion furnace 30. Further, at a predetermined position of the exhaust pipe P, an exhaust lever (not shown) for adjusting the exhaust volume is provided. By means of the lids (such as lids 50A and 50B) on the intake port 12 side described above and the exhaust lever of the exhaust pipe P, the air volume can be adjusted so that the wood in the air supply layer 22 (described later) of the cage 20 does not burn too much (within a range where the fire does not go out).

[0048] In this embodiment, the intake port 12 and the exhaust port 13 correspond to the air inlet and outlet.

[0049] <cage 20> The cage 20 is a member formed of metal and includes a cubic mesh 21 and an air supply layer 22.

[0050] The cubic mesh 21 (corresponding to the storage mesh) is a cubic container having a storage space S1 for storing the wooden formwork 3 (corresponding to wood waste) recovered from the construction site. The upper end of the cubic mesh 21 is open, and the other surfaces (including the lower surface at the boundary with the air supply layer 22) are formed of wire mesh. The used wooden formwork 3 generated at the construction site is stored in the storage space S1 of the cubic mesh 21.

[0051] The wooden formwork 3 is a plywood for concrete formwork and is surface-treated (for example, coated with urethane resin) to improve water resistance. Since such a wooden formwork 3 is a material that is difficult to separate, it is usually discarded after use. In this embodiment, this wooden formwork 3 is used as a raw material for charcoal without being discarded. Note that the wooden formwork 3 is not limited to the above, and may be, for example, a wood material other than plywood, and may not be surface-treated. Also, it may be wood (wood waste) other than formwork. Also, the type of wood is not particularly limited, and may be, for example, a broad-leaved tree or a coniferous tree.

[0052] The air supply layer 22 is provided in the lower layer of the cubic grid 21 (at a position corresponding to the intake port 12 and the exhaust port 13 of the cover body 11 in the vertical direction), and has a space S2 inside. The space S2 houses easily combustible wood waste and the like. By using wood waste as the fuel for heating, waste can be effectively utilized, and the wooden formwork 3 can be carbonized without using fossil fuels (such as petroleum, coal, natural gas, etc.) with a large CO2 emission. Also, the front and rear surfaces of the air supply layer 22 are formed of wire meshes, enabling air supply from the intake port 12 of the cover body 11, through the air supply layer 22, to the exhaust port 13. By burning the wood in the air supply layer 22 (space S2), the wooden formwork 3 housed in the cubic grid 21 is heated.

[0053] Note that the air taken in from the intake port 12 of the cover body 11 passes through the air supply layer 22 of the cage 20 and is discharged from the exhaust port 13 (suctioned into the secondary incinerator 30), so almost no air (oxygen) is supplied to the cubic grid 21. For this reason, the wooden formwork 3 housed in the cubic grid 21 does not burn but is carbonized by heating from the air supply layer 22. By carbonizing the wooden formwork 3 without combining it with oxygen to produce charcoal, charcoal rich in a large amount of carbon in a stable state can be produced.

[0054] <Secondary incinerator 30> The secondary incinerator 30 is a furnace for burning gas (gas combustion furnace), which burns the smoke flowing in from the opening 13a of the exhaust port 13 of the carbonization furnace 10 through the exhaust pipe P and discharges it from the chimney 31. Thereby, impurities contained in the smoke discharged from the carbonization furnace 10 can be removed (the smoke can be purified), and environmental considerations can be taken into account. In this embodiment, the combustion temperature of the secondary incinerator 30 is set to 800 °C or higher.

[0055] Although not shown in the drawings, the carbon production facility 1 is also provided with a carbon supply device (carbon hopper) that supplies carbon for ignition of the secondary combustion furnace 30 to the secondary combustion furnace 30, a fan for sucking air in the exhaust pipe P into the secondary combustion furnace 30, an operation panel for managing and operating combustion in the secondary combustion furnace 30, and the like. Further, a damper (such as a suction damper and an outside air intake damper) for adjusting the air flow (flow rate) is installed in the pipe line (including the exhaust pipe P) connected to the secondary combustion furnace 30.

[0056] <<Carbon production method>> FIG. 5 is a flowchart showing the carbon production method of the present embodiment.

[0057] First, the used wood materials (wood waste materials: here, the wooden formwork 3) generated at the construction site are collected (S01) and transported to the factory having the carbon production facility 1 (S02). Then, the collected wooden formwork 3 is dried (S03) and packed into the accommodation space S1 of the cubic mesh body 21 of the cage 20 (S04). Further, the space S2 of the air supply layer 22 of the cage 20 accommodates combustible waste materials (wood materials) and the like.

[0058] Next, after lifting the cover 11 of the carbonization furnace 10 and placing the cage 20 at a predetermined position, the cover 11 is lowered to install the cage 20 in the carbonization furnace 10 (S05).

[0059] Next, the wood waste material in the air supply layer 22 is ignited and burned. Then, the wooden formwork 3 accommodated in the cubic mesh body 21 is heated at a temperature of 350 °C or higher for 4 hours or more. Thereby, the carbonization of the wooden formwork 3 is performed (S06).

[0060] More specifically, before the ignition of the air supply layer 22, the carbon in the secondary combustion furnace 30 (carbon supplied from the carbon hopper) is ignited to start combustion in the secondary combustion furnace 30. Then, while sucking from the exhaust port 13 into the secondary combustion furnace 30, the air volume is adjusted to ignite the air supply layer 22 of the carbonization furnace 10 described above.

[0061] As described above, when air is discharged from the exhaust port 13, air is taken in from the suction port 12 into the cover body 11, but almost no air is supplied to the part of the cubic lattice 21 in the cover body 11. For this reason, the wooden formwork 3 housed in the cubic lattice 11 does not burn but is carbonized by the heat (heating at 350 °C or higher) from the air supply layer 22.

[0062] The air (smoke) discharged from the carbonization furnace 10 (exhaust port 13) is sent to the secondary combustion furnace 30 via the exhaust pipe P and is secondarily combusted at 800 °C or higher in the secondary combustion furnace 30 (secondary combustion step). As a result, impurities contained in the smoke are removed, and the purified smoke is discharged from the chimney 31.

[0063] Note that the conditions such as the temperature, time, and air volume of the carbonization process (step S06) are appropriately set according to the type of waste material (wood).

[0064] After the carbonization process (step S06) is completed, the cover body 11 of the carbonization furnace 10 is lifted, the cage 20 is taken out, and the carbonized wooden formwork (hereinafter also referred to as carbonized product) is taken out from the cubic lattice 21 (S07).

[0065] Also, at this time, members other than carbon (for example, nails used in the wooden formwork 3) are removed (S08). For example, nails may be removed using a magnet or the like, or may be removed manually. By removing nails and the like after carbonizing the wooden formwork 3, it is easier to remove nails and the like compared to the case of removing them before carbonization.

[0066] Next, the carbonized product is pulverized using a pulverizer or the like (S09). As for the type of pulverizer, there are a coarse pulverizer, a fine pulverizer, etc. according to the degree of pulverization (particle size), but it is desirable to use a pulverizer (for example, a fine pulverizer) capable of pulverizing the material to several mm or less. And it is desirable to perform pulverization so that the range (maximum value) of the particle size (particle diameter) becomes 30 mm or less. Thereby, the pulverized carbon (biochar) can be easily utilized effectively. Note that, as described above, members other than carbon (nails, etc.) are removed before the pulverization process, so nails and the like do not get in the way and pulverization can be performed reliably.

[0067] Next, by analyzing the pulverized material, it is determined whether the content of refractory carbon is 50% or more (S10). That is, it is determined whether carbonization is sufficient.

[0068] Note that refractory carbon refers to carbon and carbon compounds that are difficult to decompose under normal natural conditions, and the refractory carbon content refers to the mass fraction of refractory carbon. When biochar is, for example, buried in soil, only refractory carbon becomes a long-term and stable carbon storage fraction.

[0069] As a method for quantifying refractory carbon, a method according to "Japanese Biochar Promotion Association Standard JBAS 0002 Biochar for Soil Carbon Storage - Measurement Method" can be used.

[0070] In step S10, when the content of refractory carbon is less than 50% (NO in S10), the process returns to step S04 and carbonization is performed again.

[0071] On the other hand, in step S10, when the content of refractory carbon is 50% or more (YES in S10), the carbon production process ends.

[0072] Note that by including the obtained pulverized material (granular carbon) in the cement composition, the carbon dioxide (CO2) emission amount of the cement composition can be reduced.

[0073] Also, by burying the pulverized material in the soil, the organic matter can trap the carbon dioxide taken in from the atmosphere in the soil. In addition, effects such as soil improvement can be exerted.

[0074] As described above, the above embodiments are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. It goes without saying that the present invention can be changed and improved without departing from its gist, and equivalents of the present invention are included therein.

Explanation of Reference Numerals

[0075] 1 Carbon manufacturing equipment 3 Wooden formwork (wood waste) 10 Carbonization furnace 11 Cover 12 Intake port 13 Exhaust port 13a Opening 20 Cage 21 Cubic mesh body 22 Air supply layer 30 Secondary combustion furnace 31 Chimney 50A, 50B Lids 51a, 51b Openings 60 Cylindrical body S1 Accommodation space S2 Space P Drain pipe

Claims

1. A method for manufacturing charcoal from wood waste generated at a construction site, comprising: a recovery step of recovering the wood waste into a charcoal manufacturing facility; a carbonization step of carbonizing the wood waste in the charcoal manufacturing facility; A method for manufacturing charcoal, characterized by comprising the above steps.

2. The method for manufacturing charcoal according to Claim 1, wherein: the wood waste has been surface-treated; in the carbonization step, the wood waste is carbonized while remaining in the surface-treated state. A method for manufacturing charcoal, characterized by the above.

3. The method for manufacturing charcoal according to Claim 1, wherein: the fuel used for heating in the carbonization is wood waste. A method for manufacturing charcoal, characterized by the above.

4. The method for manufacturing charcoal according to Claim 1, wherein: in the carbonization, the heating temperature is 350°C or higher and the carbonization time is 4 hours or longer. A method for manufacturing charcoal, characterized by the above.

5. The method for manufacturing charcoal according to Claim 1, wherein: the carbonization step includes a secondary combustion process. A method for manufacturing charcoal, characterized by the above.

6. The method for manufacturing charcoal according to Claim 1, wherein: the charcoal has a refractory carbon content of 50% or more. A method for manufacturing charcoal, characterized by the above.

7. The method for manufacturing charcoal according to Claim 1, further comprising: a pulverization step of pulverizing the carbonized wood waste; in the pulverization step, the pulverization is performed so that the particle size range is 30 mm or less. A method for manufacturing charcoal, characterized by the above.

8. The method for manufacturing charcoal according to Claim 7, further comprising: a removal step of removing members other than carbon between the carbonization step and the pulverization step. A method for manufacturing charcoal, characterized by the above.

9. The method for manufacturing charcoal according to any one of Claims 1 to 8, wherein: the wood waste is a formwork used when placing a cement composition. A method for manufacturing charcoal, characterized by the above.

10. A charcoal manufacturing facility for manufacturing charcoal from wood waste generated at a construction site, comprising: a housing net for housing the wood waste; an air supply layer provided below the housing net; a cover covering the housing net and the air supply layer; an air inlet / outlet penetrating the cover and communicating the air supply layer with the outside air. A charcoal manufacturing facility, characterized by comprising the above.

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