Gasifier and processing method

Abstract

To provide a technology capable of enhancing combustion efficiency of biofuel in a combustion furnace and suppressing tar contained in dry distillation gas.SOLUTION: The gasification apparatus includes a cylindrical combustion furnace having a cylindrical side wall and a pair of end faces orthogonal to the side wall, into which a biofuel is fed from one of the pair of end faces, and which combusts the fed biofuel to generate a pyrolyzed gas, a circulation tube extending in an internal space of the side wall along a cross section of the side wall in one or more annular, spiral, or polygonal shapes formed substantially concentrically with an intersection line where the side wall and the cross section of the side wall intersect with each other, and one or more first inlets communicating the inside and the outside of a tube wall of the circulation tube and introducing air from the inside of the circulation tube into the internal space of the side wall.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to gasifiers and processing methods. [Background technology]

[0002] From the perspective of environmental conservation, gasification equipment and the like that utilizes dry distillation gas and charcoal generated from biomass fuels such as naturally occurring wood chips and semi-carbonized wood chips has become widespread. Dry distillation gas generated from biomass fuels (hereinafter also referred to as biofuel) can be used, for example, as fuel for power generation, and charcoal can be used as a soil improvement material (biochar).

[0003] The following patent documents exist as prior art documents that describe techniques related to the techniques described in this specification. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-36859 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-265951 Summary of the Invention [Problem to be solved by the invention]

[0005] In a gasification apparatus using biofuel, suppression of tar generated during combustion is an issue. One aspect of the present disclosure is to provide a technology that can increase the combustion efficiency of biofuel in a combustion furnace and suppress tar contained in dry distillation gas. [Means for solving the problem]

[0006] The disclosed embodiment is exemplified as a gasification apparatus. The gasification apparatus includes a cylindrical combustion furnace having a cylindrical side wall and a pair of end faces perpendicular to the side wall, where biofuel is introduced from one of the pair of end faces and the introduced biofuel is combusted to generate dry distillation gas, one or more circumferential pipes extending in an annular, spiral, or polygonal shape in the interior space of the side wall along a cross section of the side wall and formed approximately concentrically with an intersection line where the cross sections of the side walls intersect, and one or more first inlets communicating the interior and exterior of the pipe wall of the circumferential pipe and introducing air from the interior of the circumferential pipe into the interior space of the side wall.

[0007] Another embodiment of the disclosure is exemplified as a processing method. The gasification apparatus includes a cylindrical combustion furnace having a cylindrical side wall and a pair of end faces perpendicular to the side wall, where biofuel is introduced from one side of the pair of end faces and the introduced biofuel is combusted to generate dry distillation gas, and the gasification apparatus performs the following steps: introducing air from inside the circumferential tube into the internal space of the side wall through one or more first inlets communicating with the inside and outside of the circumferential tube wall, the circumferential tube extending in an annular, spiral, or polygonal shape in the internal space of the side wall and extending along the cross section of the side wall substantially concentrically with an intersection line where the cross sections of the side wall and the side wall intersect; and igniting at least a portion of the biofuel near the inlet into which the biofuel is introduced. [Effects of the Invention]

[0008] According to the disclosed embodiment, the combustion efficiency of biofuel in a combustion furnace is improved, and the tar contained in the dry distillation gas is suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating the combustion of biofuel in a gasification apparatus of a comparative example. [Figure 2] FIG. 2 is a diagram illustrating the reaction state of biofuel during combustion. [Figure 3] FIG. 3 is a diagram illustrating a combustion zone formed inside the combustion furnace of the gasification apparatus according to the embodiment. [Figure 4]FIG. 4 is a perspective view showing an example of a schematic configuration of an air introduction mechanism included in the gasification apparatus according to the embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a schematic configuration of a gasification apparatus according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, one mode for carrying out the invention (hereinafter also referred to as one embodiment or embodiment) will be described with reference to the drawings. The configuration of the following embodiment is an example, and the configuration of the gasification apparatus disclosed in this embodiment can be appropriately changed depending on the processing capacity, etc. Unless otherwise specified, the configurations disclosed in this embodiment are not intended to limit the technical scope of the invention to only those, and can be combined as much as possible.

[0011] Furthermore, the drawings referred to in the following description merely show the shapes, sizes, and positional relationships in a schematic manner to the extent that the contents of the present invention can be understood. That is, the present invention is not limited to the shapes, sizes, and positional relationships exemplified in each drawing. Furthermore, there may be parts in which the dimensional relationships and ratios differ between the drawings.

[0012] Comparative Example First, a conventional gasification apparatus 100 to which the technology of the gasification apparatus according to this embodiment can be applied will be described with reference to Figures 1 and 2. Figure 1 is a diagram illustrating the combustion of biomass fuel (hereinafter also referred to as biofuel) Z1 in a comparative gasification apparatus 100. Figure 1(a) is a diagram illustrating the state inside a combustion furnace 101 into which biofuel Z1 has been introduced, and Figure 1(b) is a diagram illustrating the reaction state that occurs inside the combustion furnace 101 when biofuel Z1 is combusted. Figure 2 is a diagram illustrating the reaction state of biofuel Z1 during combustion.

[0013] As shown in FIGS. 1(a) and 1(b), the gasification apparatus 100 is a downdraft-type apparatus having a combustion furnace 101, which is a substantially cylindrical vertical vessel. In the downdraft-type apparatus, biofuel Z1 to be treated is introduced from the upper side of the combustion furnace 101, and pyrolysis gas, charcoal, and the like generated from the biofuel Z1 by combustion are extracted from the lower side of the combustion furnace 101. Examples of biofuel Z1 used in the gasification apparatus 100 include unused resources such as naturally occurring wood chips and semi-carbonized wood chips. In FIGS. 1(a) and 1(b), Z2 indicated by solid arrows represents the flow of air during combustion, and Z3 indicated by solid arrows represents the flow of pyrolysis gas containing tar. In the gasification apparatus 100, air is supplied into the combustion furnace 101, where the biofuel Z1 is burned, through, for example, multiple supply ports provided on the circumferential surface of the combustion furnace 101. Hereinafter, the air used during combustion will also be referred to as "air Z2," and the pyrolysis gas containing tar will also be referred to as "pyrolysis gas Z3."

[0014] When combustion is performed in the gasification apparatus 100, a combustion zone Z4 and a non-combustible zone Z6 may be formed in the internal space of the combustion furnace 101 that accommodates the input biofuel Z1, as shown in Fig. 2. The combustion zone Z4 is formed, for example, in an area on the side wall where a plurality of supply ports provided on the circumferential surface of the combustion furnace 101, which is a substantially cylindrical vertical vessel, open, and the non-combustible zone Z6 is formed in an area approximately near the center.

[0015] In the downdraft type gasification apparatus 100, as shown by the thick dashed arrow Z3, the dry distillation gas (including tar) Z3 generated from the biofuel Z1 heated by heat transfer and radiation heat in the combustion furnace 101 forms a flow from the top to the bottom of the vertical container. For example, tar is a flammable gas whose main components are hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), and water (H2O). Tar is a flammable, viscous organic liquid (oil) that does not become gas components such as hydrogen, carbon monoxide (CO), or methane (CH4) when organic substances such as wood chips, which are biofuel Z1, are pyrolyzed. In the combustion furnace 101, the dry distillation gas Z3 containing tar is heated to a temperature exceeding 1000°C, for example.

[0016] Air Z2 supplied from a supply port provided on the periphery of the combustion furnace 101 flows into the region near the center from the side wall where the supply port is provided, for example, through gaps between the biofuels contained in the combustion furnace 101, as indicated by the diagonal arrows. Air Z2 supplied into the combustion furnace 101 through the supply port contains approximately 21% oxygen.

[0017] In the region near the wall of the combustion furnace 101, for example, the dry distillation gas Z3 flowing vertically from above to below and the oxygen of the air Z2 supplied from the supply port through the gaps between the biofuels react instantaneously, resulting in the combustion of tar contained in the dry distillation gas Z3. The oxygen of the air Z2 also reacts with the char produced from the burning biofuel Z1, generating carbon monoxide (CO) gas and carbon dioxide (CO2) gas. In this way, the oxygen of the air Z2 supplied into the combustion furnace 101 is consumed as it moves through the internal space.

[0018] As a result, in the gasification apparatus 100 in which biofuel Z1 is combusted, a combustion zone Z4 is formed in the internal space of the combustion furnace 101, as shown in Fig. 2, where tar reacts with oxygen in air Z2 and is combusted. Furthermore, in the internal space of the combustion furnace 101, oxygen consumption by combustion zone Z4 results in the formation of a non-combustible zone Z6, where oxygen for burning tar is absent. Combustion zone Z4 can be considered a partial region in the internal space of the combustion furnace 101 where oxygen is present, and is formed with a finite distance L that depends on the consumption of oxygen accompanying the combustion of biofuel Z1, etc. Combustion zone Z4 is formed in a spatial region on the side wall side of the combustion furnace 101, and non-combustible zone Z6 is formed in a spatial region near the center of the combustion furnace 101, and combustion zone Z4 and non-combustible zone Z6 are formed adjacent to each other in the radial direction from the side wall side toward the center of the combustion furnace 101.

[0019] In the combustion zone Z4 of the combustion furnace 101, the dry distillation gas Z3 not containing tar components flows downward due to the combustion of tar, while in the non-combustible zone Z6 where oxygen for burning tar is not present, the dry distillation gas Z3 containing tar components flows downward. In this way, the tar contained in the dry distillation gas Z3 generated from the biofuel Z1 heated in the combustion furnace 101 passes through the spatial region of the non-combustible zone Z6.

[0020] Returning to FIG. 1(b), in the internal space of the combustion furnace 101, which is a substantially cylindrical vertical container, containing the biofuel Z1, a combustion zone Z4 is formed in a substantially donut shape (ring shape) from the side wall toward the center, which is identified by a distance L. Near the center of the combustion furnace 101, a substantially cylindrical non-combustible zone Z6 is formed, in which oxygen for burning tar is not present due to oxygen consumption in the combustion zone Z4. Below the combustion zone Z4 of the combustion furnace 101, char Z5 is produced by the combustion of the biofuel Z1. In the gasification apparatus 100 of the comparative example, the dry distillation gas Z3 containing tar passes from above to below through the non-combustible zone Z6, which is a substantially cylindrical partial region formed near the center of the combustion furnace 101.

[0021] [Embodiment] Next, the gasification apparatus 10 according to this embodiment will be described with reference to Figures 3 to 5. Figure 3 is a diagram illustrating combustion zones (Z7, Z8) formed inside the combustion furnace 11 of the gasification apparatus 10 according to this embodiment. Figure 4 is a perspective view showing an example of the schematic configuration of the air introduction mechanism 20 provided in the gasification apparatus 10 according to this embodiment. Figure 5 is a diagram showing an example of the schematic configuration of the gasification apparatus 10 according to this embodiment.

[0022] As shown in FIG. 3 , the gasification apparatus 10 according to this embodiment, like the comparative example, is a downdraft-type apparatus having a combustion furnace 11, which is a cylindrical vertical vessel. However, as will be described later, the shape of the combustion furnace 11 is not limited to a substantially cylindrical shape and may be, for example, a rectangular tubular shape, as long as multiple combustion zones (Z7, Z8) can be formed in the internal space 11c of the combustion furnace 11. In the gasification apparatus 10, the biofuel Z1 to be treated is introduced into the internal space 11c from the upper side of the combustion furnace 11, and pyrolysis gas Z3, charcoal Z5, and the like generated from the biofuel Z1 by combustion are extracted from the lower side of the combustion furnace 11. In the combustion furnace 11, pyrolysis gas Z3 (including tar) generated from the biofuel Z1 heated by heat transfer and radiant heat forms a flow from the top to the bottom of the vertical vessel.

[0023] The biofuel Z1 employed in the gasification apparatus 10 is similar to that in the comparative example, and examples thereof include naturally occurring wood chips, which are unused resources, and semi-carbonized wood chips. From the viewpoint of increasing the efficiency of generating the dry distillation gas Z3, semi-carbonized wood chips are preferred. In the semi-carbonization process, the wood chips are heated to a predetermined temperature in a state where the oxygen supply is limited or blocked and water vapor is supplied to a container, and the moisture content of the chips is adjusted.

[0024] The gasification apparatus 10 according to this embodiment is provided with an air introduction mechanism 20 that is provided inside the combustion furnace 11 and that introduces air into the biofuel Z1 contained in the internal space 11c of the combustion furnace 11. The air introduction mechanism 20 supplies oxygen to the internal space 11c in which the biofuel Z1 is combusted, for burning tar contained in the dry distillation gas Z3 from the inside. In the combustion furnace 11 of the gasification apparatus 10, air supplied through the air introduction mechanism 20 flows into gaps between the biofuel particles contained near the air introduction mechanism. The oxygen in the air that flows into the gaps between the biofuel particles reacts with the heated dry distillation gas Z3 flowing from above downward, thereby burning the tar contained in the dry distillation gas Z3.

[0025] As explained using Fig. 2, the non-combustible zone is a region formed due to the absence of oxygen that burns the tar contained in the pyrolysis gas Z3. Therefore, inside the combustion furnace 11, the formation of the non-combustible zone can be prevented by adjusting the supply interval of air supplied through the air introduction mechanism 20 to a finite distance L at which the combustion zone is formed. In the gasification apparatus 10, preventing the formation of the non-combustible zone increases the combustion efficiency of the pyrolysis gas Z3 and suppresses the tar contained in the pyrolysis gas Z3.

[0026] In this embodiment, as shown in Fig. 3, ring-shaped (annular) combustion zones Z7 and Z8 are formed in multiple locations concentric with the central axis of the substantially cylindrical combustion furnace 11. Combustion zone Z7 is formed on the sidewall side in a cross section intersecting the central axis of the substantially cylindrical combustion furnace 11, and combustion zone Z8 is formed on the central axis side in a cross section intersecting the central axis of the substantially cylindrical combustion furnace 11. In combustion zone Z7, the distance between the sidewall of the combustion furnace 11 and the air introduction mechanism 20 is a finite distance L over which tar contained in the pyrolysis gas Z3 is combusted by oxygen in the air supplied through the air introduction mechanism 20. The same is true for combustion zone Z8, where the distance between the central axis side and the sidewall side of the air introduction mechanism 20 is a finite distance L over which tar contained in the pyrolysis gas Z3 is combusted by oxygen in the air supplied through the air introduction mechanism 20.

[0027] In this way, by forming multiple ring-shaped (annular) combustion zones Z7 and Z8, the area of ​​the region in which tar is combusted in the internal space 11c of the combustion furnace 11 can be increased, thereby improving the production amount of tar-free dry distillation gas Z3.

[0028] In the combustion furnace 11 in which multiple ring-shaped combustion zones Z7 and Z8 are formed, A drying zone Z9 is formed in which biofuel Z1 is dried by heat transfer and radiation from the combustion zone, and a pyrolysis zone Z10 is formed in which pyrolysis of dried biofuel Z1 is promoted. Pyrolysis zone Z10 is formed in the region immediately above and adjacent to combustion zones Z7 and Z8, and drying zone Z9 is formed in the region immediately above and adjacent to pyrolysis zone Z10.

[0029] Next, the air introduction mechanism 20 will be described with reference to Figure 4. In Figure 4, Z11 indicated by a dashed line represents the inner wall surface of the sidewall of the combustion furnace 11 on which the air introduction mechanism 20 is provided. As shown in Figure 4, the air introduction mechanism 20 includes a supply pipe 21, first connecting pipes (22a, 22b), second connecting pipes (23a, 23b), and circulating pipes (24a, 24b). In the following description, the first connecting pipes (22a, 22b), the second connecting pipes (23a, 23b), and the circulating pipes (24a, 24b) will also be collectively referred to as the first connecting pipe 22, the second connecting pipe 23, and the circulating pipe 24, respectively.

[0030] The supply pipe 21 is arranged concentrically with the central axis of the approximately cylindrical combustion furnace 11 and is connected to one end of a first connecting pipe 22, the other end of which is connected to a second connecting pipe 23. The first connecting pipe 22 extends from the supply pipe 21 through the interior space of the combustion furnace 11 toward the sidewall. The second connecting pipe 23, connected to one end of the first connecting pipe 22, extends through the interior space of the combustion furnace 11 parallel to the central axis and is connected to a circulating pipe 24. The circulating pipe 24 extends in the interior space 11c of the combustion furnace 11 along the cross section of the sidewall into one or more rings, spirals, or polygons formed approximately concentric with the central axis. Here, the cross section of the sidewall is a plane perpendicular to the central axis of the combustion furnace 11. Furthermore, since the central axis of the combustion furnace 11 is vertical in Figures 3 and 4, the cross section is also a horizontal plane. It can be said that the central axis passes through the center of the intersection line where the sidewall and the cross section intersect. In FIG. 4, circumferential pipes (24a, 24b) extending in one or more polygonal shapes formed approximately concentrically with the central axis along the cross section of the side wall of the combustion furnace 11 are shown as an example.

[0031] The circumferential surface of the circumferential pipe 24 is provided with one or more inlets that connect the inside and outside of the pipe wall of the circumferential pipe and introduce air from the inside of the circumferential pipe 24 into the internal space 11c of the combustion furnace 11. In this embodiment, the inlets provided in the circumferential pipe 24 are an example of a "first inlet." The inlets provided in the circumferential pipe 24 are provided, for example, on the circumferential surface of the circumferential pipe 24, both toward the side wall of the combustion furnace 11 and toward the central axis. In the air introduction mechanism 20, air supplied to the supply pipe 21 is supplied to the circumferential pipe 24 through the first connecting pipe 22 and the second connecting pipe 23. As described above, in this embodiment, air can be supplied through the circumferential pipe 24 of the air introduction mechanism 20 to the internal space 11c of the combustion furnace 11 where the biofuel Z1 is burned, allowing oxygen in the air to flow into gaps between the biofuel particles. The circumferential tube 24 is an example of "plural circumferential tubes", and the circumferential tubes 24a and 24b are an example of "plural circumferential tubes".

[0032] In this embodiment, as described above, one or more circumferential pipes (24a, 24b) formed approximately concentrically with the central axis along the cross section of the side wall are provided in the internal space 11c of the combustion furnace 11. The circumferential pipe 24a is provided on the side wall side of the internal space 11c of the combustion furnace 11, and the circumferential pipe 24b is provided on the central axis side. The first connecting pipe 22a and the second connecting pipe 23a that supply air from the supply pipe 21 to the circumferential pipe 24a have different lengths from the first connecting pipe 22b and the second connecting pipe 23b that supply air from the supply pipe 21 to the circumferential pipe 24b. Therefore, the first connecting pipe 22a connected to the circumferential pipe 24a and the first connecting pipe 22b connected to the circumferential pipe 24b are provided at different heights in the internal space 11c (positions in the height direction parallel to the central axis). Furthermore, the first connecting pipes 22a and 22b are provided at different radial positions with respect to the cross section of the side wall. Alternatively, the first connecting pipes 22a and 22b are arranged with a relative angular difference within a 360-degree angular range toward the circumference centered on the central axis. For example, in the example of Fig. 4, four first connecting pipes 22a and 22b are provided, and therefore one first connecting pipe 22a and its adjacent first connecting pipe 22b are arranged with an angular difference of approximately 45 degrees.

[0033] As a result, the mesh (gaps) formed by the first connecting pipes 22a, 22b form steps, and the mesh (gaps) are larger than when the first connecting pipes 22a, 22b are formed on the same plane. In the gasification apparatus 10, gaps can be formed between the biofuels Z1 along the path of movement to the combustion region where the introduced biofuel Z1 is combusted by air introduced from an inlet provided in the circulating pipes (24a, 24b). In the gasification apparatus 10 according to this embodiment, it is possible to prevent at least a portion of the biofuels Z1 contained in the internal space 11c of the combustion furnace 11 from becoming entangled with each other.

[0034] The circumferential pipe 24 is positioned in the cross section of the combustion furnace 11 so as to form multiple combustion zones Z7 and Z8 in which tar contained in the dry distillation gas Z3 is combusted by oxygen in the air introduced through the inlet of the circumferential pipe 24 during combustion of the biofuel Z1. That is, as shown in FIG. 3, the circumferential pipe 24a is positioned so as to form a combustion zone Z7 defined by a finite distance L between it and the side wall of the combustion furnace 11. Similarly, the circumferential pipe 24b is positioned in the cross section of the combustion furnace 11 so as to form a combustion zone Z8 defined by a finite distance L between it and the circumferential pipe 24a. In this way, multiple ring-shaped combustion zones Z7 and Z8 can be formed in the internal space 11c of the combustion furnace 11 in which the air introduction mechanism 20 is provided. The air introduction mechanism 20 may be fixedly provided inside the combustion furnace 11 or may be rotatable about the central axis of the combustion furnace 11.

[0035] Next, with reference to FIG. 5, a schematic configuration of the gasification apparatus 10 according to this embodiment will be described. 5 illustrates a gasification apparatus 10 including an air introduction mechanism 20 configured to rotate within a cross section (Z13 shown by a dashed line) of the combustion furnace 11, with the central axis (Z12 shown by a dashed line) of the substantially cylindrical combustion furnace 11 as the rotation axis. Hereinafter, these will also be referred to as the central axis Z12 or the cross section Z13.

[0036] The combustion furnace 11 has a pair of end faces perpendicular to the side walls, and an inlet 12b for introducing the biofuel Z1 into the internal space 11c is opened at the upper end face in the direction of the central axis Z12. An openable door 12a is provided at the inlet 12b. An ignition device 14 for igniting at least a portion of the biofuel Z1 introduced into the internal space 11c is provided near the inlet 12b of the combustion furnace 11. Examples of the ignition device 14 include a heater that heats the introduced biofuel Z1 to a flammable temperature and a burner that ignites the introduced biofuel Z1. The ignition device 14 operates to stop ignition of the introduced biofuel Z1 when combustion zones Z7 and Z8 are formed in the internal space of the combustion furnace 11, where the air introduction mechanism 20 is provided. In the combustion furnace 11, a pipe 15 for extracting the dry distillation gas Z3 purified by burning the tar is connected to the end face opposite to the end face where the inlet 12b is provided.

[0037] An air inlet 13 is provided in the side wall of the combustion furnace 11, connecting the side wall outer surface 11a and the side wall inner surface 11b. One or more air inlets 13 are formed, for example, on the wall surface on the intersection line where the side wall of the combustion furnace 11 intersects with the cross section Z13. By providing the air inlet 13, the combustion efficiency of the tar contained in the pyrolysis gas Z3 can be further improved. However, the air inlet 13 does not necessarily have to be provided in the combustion furnace 11. It can be configured appropriately depending on the performance of the gasification apparatus 10, the production amount of the pyrolysis gas Z3 not containing tar, etc. In this embodiment, the air inlet 13 is an example of a "second inlet."

[0038] The combustion furnace 11 is provided with a rotating shaft 33 that extends through the internal space 11c along the central axis Z12, and one end of the rotating shaft 33 is connected to one end of the supply pipe 21 of the air introduction mechanism 20. The other end of the rotating shaft 33 is concentrically connected to a sprocket 32 ​​provided outside the combustion furnace 11. The sprocket 32 ​​is connected to a drive device composed of a chain 31, a motor 30, etc. By the rotation of a sprocket 32 ​​connected to the shaft center of the motor 30 via a chain 31, the air introduction mechanism 20 rotates concentrically with the central axis Z12 in the cross section of the internal space 11c of the combustion furnace 11. The supply pipe 21, the first connecting pipe 22, the second connecting pipe 23, and the circulating pipe 24 that constitute the air introduction mechanism 20 rotate concentrically with a rotation shaft 33 that extends through the internal space 11c along the central axis Z12.

[0039] The other end of the supply pipe 21 of the air introduction mechanism 20 is rotatably connected to a rotary joint 42, which is a joint provided outside the combustion furnace 11. One end of a pipe 41, the other end of which is connected to a blower 40, is connected to the rotary joint 42, and air supplied from the blower 40 is supplied to the supply pipe 21 of the air introduction mechanism 20 provided inside the combustion furnace 11. The air supplied from the blower 40 is supplied to each of the circulating pipes 24a and 24b through the first connecting pipe 22 and the second connecting pipe 23.

[0040] The air supplied to the circumferential pipe 24a is introduced into the internal space 11c of the combustion furnace 11 through one or more inlets provided in the pipe wall. The air introduced into the internal space 11c through the inlet of the circumferential pipe 24a forms a combustion zone Z7 between the circumferential pipe 24a and the side wall of the combustion furnace 11, for example. Similarly, the air supplied to the circumferential pipe 24b is introduced into the internal space 11c of the combustion furnace 11 through one or more inlets provided in the pipe wall. The air introduced into the internal space 11c through the inlet of the circumferential pipe 24b forms a combustion zone Z8 between the circumferential pipe 24b and the supply pipe 21, for example.

[0041] In this way, in the gasification apparatus 10, multiple ring-shaped combustion zones (Z7, Z8) can be formed in the internal space 11c of the combustion furnace 11, thereby relatively increasing the area of ​​the region in which tar is combusted. For example, in the gasification apparatus 100 of the comparative example, a non-combustible zone Z6 is formed, and therefore large European-type wood chips (fist-sized) are used as the biofuel Z1 in order to relatively increase the area of ​​the combustion zone Z4 in the combustion furnace 101. However, in this embodiment, the area of ​​the combustion zones (Z7, Z8) formed in the combustion furnace 11 can be increased without forming a non-combustible zone Z6, so that, for example, papermaking wood chips, which are smaller than European-type chips, can be used as the biofuel Z1. Papermaking wood chips are, for example, approximately 3 to 5 mm on a side and several mm thick. Papermaking wood chips are available in large quantities, and papermaking chip manufacturing equipment is easily available. According to the gasification apparatus 10 of this embodiment, it is possible to suppress the procurement costs for procuring the biofuel Z1 and reduce the production costs for the refined dry distillation gas Z3.

[0042] (Other embodiments) The above-described embodiment is merely an example, and the disclosure of the present embodiment may be appropriately modified and implemented without departing from the spirit thereof. The processes and means described in the present disclosure may be freely combined and implemented as long as no technical contradiction occurs.

[0043] For example, while FIG. 4 illustrates the circumferential tubes 23 and 24, the number of the circumferential tubes 23, etc. is not limited to two. That is, as shown in FIG. 3, the circumferential tubes 24b are arranged so as to form a combustion zone Z7 defined by a finite distance L between them and the side wall of the combustion furnace 11. Similarly, the circumferential tube 24b is arranged in a cross section of the combustion furnace 11 so as to form a combustion zone Z8 defined by a finite distance L between it and the circumferential tube 24a. Therefore, for example, assuming that the combustion furnace 11 is a cylinder with a cross-sectional radius of the internal space 11c having a radius R11, as the radius R11 of the internal space 11c perpendicular to the central axis increases, the number of circumferential tubes becomes three or more.

[0044] For example, in FIG. 3, the radius of the supply pipe 21 is R21, and the diameters of the circulating pipes 23 and 24 are D23 and D24. In this case, the radius R11 of the cross section of the internal space 11c is R21+D23+L If the total length is greater than +D24+L, it becomes difficult to supply oxygen to the entire internal space 11c using only the circumferential pipes 23 and 24. Therefore, a third circumferential pipe is required. Furthermore, the same calculation is performed when the internal space 11c of the combustion furnace 11 becomes larger. Therefore, the number of circumferential pipes, first connecting pipes, and second connecting pipes is set appropriately depending on the combustion furnace 11. [Explanation of symbols]

[0045] 10, 100·· Gasification apparatus, 11, 101·· Combustion furnace, 11a·· Outer surface of side wall, 11b·· Inner surface of side wall, 11c·· Internal space, 12a·· Openable door, 12b·· Inlet, 13·· Air inlet (second inlet), 14·· Ignition device, 15, 41·· Piping, 20·· Air introduction mechanism, 21·· Supply pipe, 22, 22a, 22b·· First connecting pipe, 23, 23a, 23b·· Second connecting pipe, 24, 24a, 24b b··Circumferential pipe, 30··Motor, 31··Chain, 32··Sprocket, 33··Rotating shaft, 40··Blower, 42··Rotary joint (coupling), Z1··Biofuel, Z2··Air, Z3··Drying gas, Z4, Z7, Z8··Combustion zone, Z5··Carbonized material, Z6··Non-combustible zone, Z9··Drying zone, Z10··Pyrolysis zone, Z11··Inner wall surface, Z12··Central axis, Z13··Cross section

Claims

1. a cylindrical combustion furnace having a cylindrical side wall and a pair of end faces perpendicular to the side wall, into which biofuel is introduced from one side of the pair of end faces and which burns the introduced biofuel to generate dry distillation gas; In the internal space of the side wall, one or more circular, spiral, or polygonal circumferential tubes are formed along a cross section of the side wall and extend substantially concentrically with an intersection line where the cross sections of the side wall and the side wall intersect; one or more first inlets that communicate the inside and outside of the pipe wall of the circumferential pipe and introduce air from the inside of the circumferential pipe into the internal space of the side wall; A gasification apparatus comprising:

2. 2. The gasification apparatus according to claim 1, further comprising: a supply pipe arranged concentrically with a central axis of the cylindrical combustion furnace and supplying air to the circumferential pipe; and a connecting pipe extending from the supply pipe through the internal space toward a side wall of the cylindrical combustion furnace and connecting the supply pipe and the circumferential pipe.

3. a joint that rotatably connects the supply pipe to a pipe outside the combustion furnace, the supply pipe being connected to a blower through the joint and the pipe; The gasification apparatus according to claim 1 , wherein the circulating pipe, the supply pipe, and the connecting pipe formed in the internal space of the side wall are rotated by a driving device.

4. The gasification apparatus according to claim 1 , wherein the first inlet is provided in the circulating pipe both in the direction of the central axis of the cylindrical combustion furnace and in the direction of a side wall of the cylindrical combustion furnace.

5. The circumferential tube is provided in plurality, 3. The gasification apparatus according to claim 2, wherein the connecting pipes include a first connecting pipe extending in a sidewall direction of the cylindrical combustion furnace and a second connecting pipe extending from the first connecting pipe parallel to a central axis of the cylindrical combustion furnace, the second connecting pipes have different lengths for each of the plurality of circumferential pipes, and the first connecting pipes connected to each of the plurality of circumferential pipes are provided at different heights for each of the plurality of circumferential pipes in a height direction parallel to the central axis.

6. 2. The gasification apparatus according to claim 1, further comprising one or more second inlets that communicate the inside and outside of the side wall, introduce air into the internal space of the side wall, and are formed on an intersection line where the cylindrical side wall intersects with a cross section of the side wall.

7. The gasification apparatus according to claim 1 , further comprising an ignition device (heater, burner) for igniting at least a portion of the biofuel near an inlet into which the biofuel is introduced.

8. 8. The gasification apparatus according to claim 7, wherein a central axis of the cylindrical combustion furnace is formed in a vertical direction, and when a combustion zone is formed by the ignited biofuel below the first inlet in the vertical direction, ignition by the ignition device is stopped.

9. A processing method for a gasification apparatus including a cylindrical combustion furnace having a cylindrical side wall and a pair of end faces perpendicular to the side wall, wherein a biofuel is introduced from one side of the pair of end faces and the introduced biofuel is combusted to generate a dry distillation gas, the method comprising: introducing air from inside the circulating tube into the internal space of the side wall through one or more first inlets communicating the inside and outside of the wall of one or more circular, spiral, or polygonal circulating tubes formed in the internal space of the side wall along a cross section of the side wall and substantially concentric with an intersection line where the side wall and the cross section of the side wall intersect; At least a part of the biofuel is ignited near an inlet into which the biofuel is introduced. and a processing method for carrying out the steps.

10. 10. The treatment method according to claim 9, further comprising a step of stopping ignition of the ignition device when a central axis of the cylindrical combustion furnace is formed in a vertical direction and a combustion zone is formed by the ignited biofuel below the first inlet in the vertical direction.

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