Biomass gasification reactor

Abstract

To provide a biomass gasification furnace capable of efficiently decomposing a tar component contained in fuel gas.SOLUTION: There is provided a biomass gasification furnace 1 which heats and gasifies a woody biomass raw material F to produce fuel gas G. The biomass gasification furnace 1 comprises an outer cylinder 10 provided so that the axis C extends in the vertical direction, an inner cylinder 20 provided inside the outer cylinder 10 so that the axis C extends in the vertical direction and a lower end 20b is located above a lower end 10b of the outer cylinder 10, a reaction furnace 30 which heats the outer cylinder 10 from the outside, a combustion air supply part 40 which is provided inside the inner cylinder 20b and supplies combustion air A. The biomass gasification furnace 1 has a plurality of connecting passages 50 in a space S between the inner cylinder 20 and the outer cylinder 10, which are provided extending in a vertical direction so that an upper part SA and a lower part SB of the space S are connected. The biomass raw material F is supplied inside the inner cylinder 20 from above to produce fuel gas G based on the biomass raw material F and the fuel gass G produced is guided through the plurality of connecting passages 50 from below to above and then discharged.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a biomass gasification furnace.

Background Art

[0002] Biomass raw materials are carbonized by a biomass gasification furnace to produce fuel gas, and the fuel gas is burned by an internal combustion engine to generate electricity.

[0003] As such a biomass gasification furnace, for example, Patent Document 1 discloses a biomass gasification device including a double tube having an inner tube and an outer tube arranged to extend in the vertical direction within a furnace body. The furnace body heats the double tube. The double tube is composed of an inner tube and an outer tube. The inner space of the inner tube is a space for gasifying biomass raw materials. The biomass raw materials supplied from the upper part of the double tube accumulate in the lower part of the inner space of the inner tube. The biomass raw materials sequentially react while moving downward in the inner space of the inner tube to generate fuel gas. The space between the inner tube and the outer tube is a space through which the generated fuel gas flows. A suction fan is provided in a generated gas discharge pipe provided at the upper end of the outer tube, and the generated fuel gas is discharged to the outside thereby.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when biomass raw materials are thermally decomposed to produce fuel gas, tar components are generated and discharged mixed with the fuel gas. When these tar components are cooled and liquefied, they become viscous. If viscous tar components adhere to the mechanical drive parts of equipment that uses fuel gas, such as the intake pipe and intake valve of an internal combustion engine, malfunctions may occur in the mechanical drive parts, such as the intake valve sticking to the intake pipe. Therefore, it is desirable to have a low amount of tar components in the fuel gas. In the configuration of Patent Document 1, as the fuel gas passes through the annular space between the inner and outer cylinders, the annular space is heated by the furnace body, which can decompose the tar components in the fuel gas. However, if the fuel gas is not heated sufficiently, the tar components in the fuel gas will not be sufficiently decomposed, and as a result, the discharged fuel gas may contain a large amount of tar components.

[0006] The object of this invention is to provide a biomass gasification furnace capable of efficiently decomposing tar components contained in fuel gas. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following means. In other words, the biomass gasifier of the present invention is a biomass gasifier that heats and gasifies woody biomass raw material to produce fuel gas, comprising: an outer cylinder provided with an axis extending in the vertical direction; an inner cylinder provided inside the outer cylinder with an axis extending in the vertical direction and its lower end located above the lower end of the outer cylinder; a reaction furnace that heats the outer cylinder from the outside; and a combustion air supply unit provided inside the inner cylinder to supply combustion air, wherein the space between the inner cylinder and the outer cylinder is provided with a plurality of connecting passages that extend in the vertical direction so that the upper and lower parts of the space are in communication, the biomass raw material is supplied to the inside of the inner cylinder from above, the fuel gas is produced based on the biomass raw material, and the produced fuel gas is guided through the plurality of connecting passages from bottom to top before being discharged. Multiple tubular members extending in the vertical direction are provided in the space between the inner cylinder and the outer cylinder, and the connecting passage is formed inside the tubular members, and a plate material is provided in the space between the inner cylinder and the outer cylinder to divide the space vertically, and the multiple tubular members penetrate the plate material in the vertical direction and are supported by the plate material, and the inner cylinder and the outer cylinder are each cylindrical in shape extending in the vertical direction, and the multiple tubular members are arranged at intervals in the circumferential direction around the axes of the inner cylinder and the outer cylinder. ru. Furthermore, the biomass gasifier of the present invention is a biomass gasifier that heats woody biomass raw material to gasify it and produce fuel gas, comprising: an outer cylinder provided with an axis extending in the vertical direction; an inner cylinder provided inside the outer cylinder with an axis extending in the vertical direction and its lower end located above the lower end of the outer cylinder; a reaction furnace that heats the outer cylinder from the outside; and a combustion air supply unit provided inside the inner cylinder to supply combustion air, wherein the space between the inner cylinder and the outer cylinder is provided with a plurality of connecting passages that extend in the vertical direction so that the upper and lower parts of the space are in communication, and the biomass raw material is supplied to the inside of the inner cylinder from above, and the biomass gasifier is provided inside the inner cylinder, and the biomass gasifier is provided inside the outer The fuel gas is generated from omas raw material, and the generated fuel gas is guided through a plurality of communication passages from bottom to top before being discharged. A plurality of tubular members extending in the vertical direction are provided in the space between the inner cylinder and the outer cylinder, and the communication passages are formed inside the tubular members. The inner cylinder and the outer cylinder are each cylindrical in shape and extend in the vertical direction. The plurality of tubular members comprises a plurality of first tubular members arranged around the axes of the inner cylinder and the outer cylinder, and a plurality of second tubular members arranged radially outward from the plurality of first tubular members around the axis, and the second tubular members have a larger diameter than the first tubular members. [Effects of the Invention]

[0008] According to the present invention, it becomes possible to efficiently decompose tar components contained in fuel gas. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing the configuration of a biomass gasification furnace according to an embodiment of the present invention. [Figure 2] Figure 1 is a schematic cross-sectional view of the vicinity of the reactor. [Figure 3] This figure shows an example of the arrangement of multiple tubular members provided in the space between the inner and outer cylinders, and is a cross-sectional view taken along arrow II in Figure 2. [Figure 4] This figure shows a tubular member and a plate material provided in the space between the inner and outer cylinders, and is a cross-sectional view taken along the line II-II in Figure 3. [Figure 5] This is a plan view showing the plate material installed in a biomass gasification furnace. [Figure 6] This figure shows a modified example of multiple tubular members provided in the space between the inner and outer cylinders. [Figure 7] This figure shows a modified example of multiple connecting passages provided in the space between the inner cylinder and the outer cylinder. [Figure 8] This figure shows another variation of the multiple connecting passages provided in the space between the inner and outer cylinders. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 shows a cross-sectional view illustrating the configuration of a biomass gasification reactor according to an embodiment of the present invention. Figure 2 shows a schematic cross-sectional view of the vicinity of the reactor in Figure 1. The following explanation will mainly use Figure 2. The biomass gasifier 1 indirectly heats woody biomass raw material F to gasify it and produce fuel gas G. The biomass gasifier 1 mainly comprises an outer cylinder 10, an inner cylinder 20, a reactor 30, a combustion air supply unit 40, multiple connecting passages 50, and a control unit 80.

[0011] The outer cylinder 10 is provided such that its axis C extends in the vertical direction. The outer cylinder 10 integrally comprises a cylindrical tubular portion 11 extending vertically along the axis C, a top plate portion 12 that closes the upper end of the tubular portion 11, and a bottom plate portion 13 that closes the lower end of the tubular portion 11.

[0012] The inner cylinder 20 is provided at a distance from the outer cylinder 10, radially inward, around axis C. The inner cylinder 20 is formed in a cylindrical shape such that axis C extends in the vertical direction. As a result, the outer cylinder 10 and the inner cylinder 20 form a double-cylinder structure centered on the same axis C. Inside the inner cylinder 20, a cylindrical internal space S1 extending in the vertical direction is formed. The lower end 20b of the inner cylinder 20 is positioned above the lower end 10b of the outer cylinder 10. The upper part 20t of the inner cylinder 20 protrudes upward, penetrating the top plate portion 12 of the outer cylinder 10.

[0013] An opening 20h is formed at the upper end of the inner cylinder 20, opening upward. The opening 20h is the input port for the biomass raw material F. The biomass raw material F is transported from the outside to the upper part of the inner cylinder 20 by a biomass conveyor 60 (see Figure 1), such as a flight conveyor, and supplied from above the opening 20h by a biomass raw material supply machine 61 (see Figure 1), such as a screw feeder, and fed into the internal space S1 inside the inner cylinder 20. The fed biomass raw material F accumulates inside the inner cylinder 20 and between the lower end 10b of the outer cylinder 10 and the lower end 20b of the inner cylinder 20, forming an accumulation section 100.

[0014] Inside the inner cylinder 20, a rotating pipe 41 is provided. The rotating pipe 41 is provided so as to extend in a tubular shape in the vertical direction along the axis C around the same axis C as the outer cylinder 10 and the inner cylinder 20. The upper part 41t of the rotating pipe 41 extends above the lower end 20b of the inner cylinder 20 and terminates inside the inner cylinder 20. The lower end portion 41b of the rotating pipe 41 penetrates the bottom plate portion 13 of the outer cylinder 10 and protrudes downward. The rotating pipe 41 is rotationally driven in the circumferential direction around the axis C by a rotating mechanism 43 such as a motor provided below the bottom plate portion 13 (see FIG. 1).

[0015] The combustion air supply portion 40 is formed in the upper part 41t of the rotating pipe 41. The combustion air supply portion 40 is provided inside the inner cylinder 20. The combustion air supply portion 40 has a plurality of air circulation holes 42. The plurality of air circulation holes 42 are provided at intervals upward from the lower end 20b of the inner cylinder 20. The plurality of air circulation holes 42 are formed so as to penetrate the inside and outside of the rotating pipe 41 in a portion above the lower end 20b of the inner cylinder 20. Combustion air A is sent into the rotating pipe 41 from a combustion air supply port 44 provided at the lower end portion 41b of the rotating pipe 41. The combustion air supply portion 40 supplies the combustion air A sent into the rotating pipe 41 from the plurality of air circulation holes 42 into the deposition portion 100 on the outer side in the radial direction centered on the axis C. By blowing out the combustion air A from the combustion air supply portion 40 while rotating the rotating pipe 41 in the circumferential direction around the axis C, the combustion air A can be evenly supplied over the entire circumference in the deposition portion 100. Here, as the combustion air A, it is preferable to use highly pure oxygen (pure oxygen). Although air may be used as the combustion air A, nitrogen contained in the air is introduced into the biomass gasification furnace 1 and mixes with the generated fuel gas G without being used in the chemical reaction in the deposition portion 100, resulting in dilution of the fuel gas G. In contrast, by increasing the purity of the oxygen used in the reaction as the combustion air A, it is possible to suppress the dilution of the fuel gas G.

[0016] A space S that forms an annular shape when viewed from above is formed between the inner cylinder 20 and the outer cylinder 10. This space S extends continuously in the vertical direction from the lower end 20b of the inner cylinder 20 to the top plate portion 12 of the outer cylinder 10. At the bottom within the outer cylinder 10, which is located below the lower end 20b of the inner cylinder 20, a circular bottom space S3 is formed when viewed from above. The bottom space S3 is formed below the internal space S1 and the space S. The internal space S1 and the space S communicate with each other via the bottom space S3.

[0017] FIG. 3 is a view showing an arrangement example of a plurality of tubular members provided in the space between the inner cylinder and the outer cylinder, and is a cross-sectional view taken along the line I-I in FIG. 2. FIG. 4 is a view showing the tubular members and plate materials provided in the space between the inner cylinder and the outer cylinder, and is a cross-sectional view taken along the line II-II in FIG. 3. As shown in FIGS. 2 to 4, a plurality of communication paths 50 are provided in the space S between the inner cylinder 20 and the outer cylinder 10. In the present embodiment, the plurality of communication paths 50 are formed inside a plurality of tubular members 51. The plurality of tubular members 51 are arranged in the space S between the inner cylinder 20 and the outer cylinder 10. The plurality of tubular members 51 are provided at intervals in the lateral direction. Particularly in the present embodiment, the plurality of tubular members 51 are arranged concentrically at intervals in the circumferential direction around the axis C of the cylindrical inner cylinder 20 and outer cylinder 10. Each tubular member 51 extends in the vertical direction. The communication path 50 is formed inside each tubular member 51. Thereby, the plurality of communication paths 50 are provided to extend in the vertical direction so that the upper portion SA and the lower portion SB of the space S communicate with each other. In the present embodiment, the plurality of tubular members 51 are formed so that their cross-sections are circular. The cross-sectional shape of the tubular member 51 is not limited to a circular shape, and may be formed, for example, in a polygonal shape.

[0018] FIG. 5 is a plan view showing the plate materials provided in the biomass gasification furnace. The upper ends of the multiple tubular members 51 are joined to a plate member 53. The plate member 53 is provided extending laterally above the space S between the inner cylinder 20 and the outer cylinder 10. The plate member 53 is formed in an annular shape when viewed from above and is provided to close the space between the inner cylinder 20 and the outer cylinder 10, thereby dividing the space S between the inner cylinder 20 and the outer cylinder 10 vertically. The plate member 53 is joined to either the outer circumferential surface of the inner cylinder 20 or the inner circumferential surface of the outer cylinder 10. In this way, the multiple tubular members 51 are supported by the plate member 53. As shown in Figure 5, the plate material 53 has multiple through holes 53h formed at intervals in the circumferential direction. Each tubular member 51 is inserted into and supported inside each through hole 53h and penetrates the plate material 53 in the vertical direction.

[0019] As shown in Figures 2 and 4, in the internal space S1 of the inner cylinder 20, the fuel gas G generated from the deposit section 100 is sucked in by the fan 17 (described later) and guided through the bottom space S3 to the space S on the outer circumference between the inner cylinder 20 and the outer cylinder 10. As shown in Figure 4, the fuel gas G guided into space S is sucked in from the lower end of the tubular member 51 into the connecting passage 50 inside the tubular member 51 and guided through the connecting passage 50 from bottom to top. However, as already explained, in the space S between the inner cylinder 20 and the outer cylinder 10, the area Sk outside the tubular member 51 is blocked from above by the plate material 53. Therefore, some of the fuel gas G Gs guided into space S temporarily remains in the area Sk outside the tubular member 51. This fuel gas G remaining in the area Sk outside the tubular member 51 is also sucked in by the fan 17 and is ultimately drawn into the connecting passage 50 from the lower end of the tubular member 51.

[0020] As shown in Figure 2, the reactor 30 heats the outer cylinder 10 from the outside. The reactor 30 is formed to surround the cylindrical portion 11 of the outer cylinder 10 from the radially outer side of the outer cylinder 10. The reactor 30 integrally has an outer peripheral wall 31, an upper wall 32, and a bottom wall 33. The outer peripheral wall 31 is provided at a distance from the cylindrical portion 11 of the outer cylinder 10 radially outward with respect to the axis C. The outer peripheral wall 31 is formed in a cylindrical or rectangular shape that extends in the vertical direction. The cross-sectional shape of the outer peripheral wall 31 when viewed from above may be any shape, such as circular, elliptical, or polygonal. The upper wall 32 is positioned below the upper end of the cylindrical portion 11 of the outer cylinder 10. The upper wall 32 closes the space between the upper end of the outer peripheral wall 31 and the cylindrical portion 11 of the outer cylinder 10 from above. The bottom wall portion 33 is positioned at approximately the same height as the bottom plate portion 13 of the outer cylinder 10. The bottom wall portion 33 closes the space between the lower end of the outer peripheral wall portion 31 and the cylindrical portion 11 of the outer cylinder 10 from below. The entire reactor 30 is covered with an insulating material 38 (see Figure 1).

[0021] The reactor 30 further includes a fluid inlet 34 and a fluid outlet 35. The fluid inlet 34 is formed at the bottom of the reactor 30. The fluid inlet 34 is for introducing high-temperature fluid H supplied from outside the reactor 30 into the reactor 30. For example, a gas with a temperature of 1000°C or higher is used as the high-temperature fluid H. The high-temperature fluid H introduced into the reactor 30 from the fluid inlet 34 heats the outer cylinder 10 from the outside. The thermal energy of the high-temperature fluid H heating the outer cylinder 10 is also transmitted from the outer cylinder 10 through the space S by radiant heat transfer, etc., to the tubular member 51 and the inner cylinder 20, heating the tubular member 51 and the inner cylinder 20 from the outside. The fluid outlet 35 is formed at the top of the reactor 30. The fluid outlet 35 is for discharging the high-temperature fluid H introduced into the reactor 30 to the outside of the reactor 30. The excess thermal energy of the high-temperature fluid H, which is discharged from the fluid outlet 35 after being used in the reaction process, can be utilized, for example, in a suitable boiler, heat exchanger, etc.

[0022] The outer cylinder 10 further includes a fuel gas discharge section 15 and a sediment discharge section 16. The fuel gas discharge section 15 is formed on the upper side (top) of the outer cylinder 10 so as to communicate the space S between the inner cylinder 20 and the outer cylinder 10 with the outside of the outer cylinder 10. The fuel gas discharge section 15 discharges the fuel gas G in the space S to the outside of the outer cylinder 10. A fan 17 is provided on the outside of the fuel gas discharge section 15. The fan 17 is rotationally driven by a drive source such as a motor (not shown). The fan 17 is designed to create negative pressure in the space S, drawing in the fuel gas G in the space S through multiple communication passages 50 and guiding it to the fuel gas discharge section 15. The fuel gas discharge section 15 is connected to an external duct (not shown). The fuel gas G discharged from the fuel gas discharge section 15 into the duct is filtered by a high-temperature filter and cooled to, for example, 40°C or below by a gas cooler. The cooled fuel gas G is supplied by the fan 17 to appropriate downstream equipment such as an internal combustion engine.

[0023] The sediment discharge section 16 is provided at the lower end 10b of the outer cylinder 10. The sediment discharge section 16 is cylindrical or rectangular in shape and extends downward from the bottom plate portion 13 of the outer cylinder 10. The sediment discharge section 16 has an upper end opening 16h. The upper end opening 16h opens upward within the outer cylinder 10 at the bottom plate portion 13. Through the sediment discharge section 16, the sediment T located at the lower end of the sediment section 100 is discharged to the outside of the outer cylinder 10 as discharged material Z.

[0024] The biomass gasifier 1 is equipped with an emission promotion unit 18. The emission promotion unit 18 has, for example, a swivel vane 19 joined to the outer circumferential surface of the rotating pipe 41. The swivel vane 19 extends radially outward from the outer circumferential surface of the rotating pipe 41 about axis C. Multiple swivel vanes 19 (for example, four) are arranged in the circumferential direction about axis C. The swivel vane 19 rotates or oscillates circumferentially about axis C in conjunction with the rotating pipe 41. In this embodiment, the swivel blade 19 comprises an upper swivel blade 19A provided near the lower end of the inner cylinder 20 and a lower swivel blade 19B provided at the lower end (bottom) inside the outer cylinder 10. The upper swivel blade 19A pushes downward the sediment T located in the upper part of the bottom space S3 between the lower end 10b of the outer cylinder 10 and the lower end 20b of the inner cylinder 20 within the accumulation section 100. The lower swivel blade 19B guides the sediment T located at the lower end (bottom) inside the outer cylinder 10 to the sediment discharge section 16. In this way, the discharge promotion section 18 promotes the discharge of the sediment T through the sediment discharge section 16. At the lower end of the accumulation section 100, the sediment T is in a carbonized and fluidized state. The discharge promotion section 18 pushes downward the sediment T, which has become fluidized at the bottom inside the outer cylinder 10. The sediment T that is pushed downward is discharged to the outside of the outer cylinder 10 through the upper end opening 16h and the sediment discharge section 16.

[0025] The control unit 80 controls the operation of the biomass gasifier 1. The biomass gasifier 1 is equipped with a sensor 81. The sensor 81 detects the height of the accumulation section 100 inside the inner cylinder 20, that is, the position of the upper end of the accumulation section 100. Based on the height of the accumulation section 100 detected by the sensor 81, the control unit 80 controls the operation of the biomass raw material supply machine 61 and the discharge promotion unit 18. If the height of the accumulation section 100 detected by the sensor 81 is below a predetermined height threshold located above the combustion air supply unit 40, the control unit 80 stops the discharge promotion unit 18 and supplies biomass raw material F from the biomass raw material supply machine 61. If the height of the accumulated material T detected by the sensor 81 exceeds the height threshold, the control unit 80 continues to supply biomass raw material F from the biomass raw material supply machine 61 while operating the discharge promotion unit 18.

[0026] In such a biomass gasifier 1, biomass raw material F is supplied from above the opening 20h. The biomass raw material F is, for example, branches, leaves, bark, etc. Prior to being fed into the biomass gasifier 1, the biomass raw material F is crushed into small pieces. If the biomass raw material F is granular, it is preferable that the particle size distribution is such that particles with a diameter of about 10 mm are the most numerous. If it is in the form of elongated shapes, so-called pin tips, it is preferable that the maximum length be about 50 mm.

[0027] The biomass raw material F introduced into the internal space S1 inside the inner cylinder 20 from the opening 20h accumulates in the bottom space S3 between the lower end 10b of the outer cylinder 10 and the lower end 20b of the inner cylinder 20, and in the internal space S1 of the inner cylinder 20, forming an accumulation section 100.

[0028] The deposit section 100 is formed by depositing material from the bottom plate 13 of the outer cylinder 10 to a position above the upper end of the rotating pipe 41 of the combustion air supply section 40 inside the inner cylinder 20. The deposit T located at the lower end of the deposit section 100 inside the outer cylinder 10 is guided to the deposit discharge section 16 by the discharge promotion section 18 and sequentially discharged to the outside of the outer cylinder 10. As a result, the deposit T forming the deposit section 100 descends (settles) sequentially from top to bottom. Even as the deposit T descends, the height of the deposit section 100 is maintained because biomass raw material F is continuously supplied from the biomass raw material supply machine 61.

[0029] As the biomass raw material F introduced into the internal space S1 inside the inner cylinder 20 descends sequentially from top to bottom, forming the deposit T that constitutes the deposit section 100, a fuel gas G containing a large amount of combustible carbon monoxide and hydrogen is generated. In the deposition section 100, tar components, which are high-molecular-weight hydrocarbons, may be generated. When cooled and liquefied, these tar components become viscous. Therefore, if the fuel gas G produced by the biomass gasifier 1 contains a large amount of tar components, the tar components may adhere to the mechanical drive parts of downstream equipment that uses the fuel gas G, potentially causing malfunctions in the mechanical drive parts. For this reason, it is desirable to have a small amount of tar components in the fuel gas G. Such tar components are oxidized and decomposed by the combustion air A supplied to the deposition section 100.

[0030] The generated fuel gas G is sucked in by the fan 17 at the lower end of the deposit T in the deposit section 100 and guided radially outward into the space S between the inner cylinder 20 and the outer cylinder 10. It then rises from bottom to top through a plurality of connecting passages 50 provided in the space S between the inner cylinder 20 and the outer cylinder 10. During this process, the decomposition of tar components in the fuel gas G is accelerated by the heat from the reactor 30. Here, since a tubular member 51 forming multiple communication passages 50 is provided in the space S between the inner cylinder 20 and the outer cylinder 10, the number of components heated by the heat supplied from the reactor 30 from the outside of the outer cylinder 10 is greater compared to the case where the tubular member 51 is not provided. As a result, the heat transfer area, i.e., the total surface area of ​​the components that heat the fuel gas G by radiant heat transfer, is increased compared to the case where the tubular member 51 is not provided, and the fuel gas G is heated more efficiently. Furthermore, the outer region Sk of the tubular member 51 is blocked from above by the plate material 53. Therefore, some of the fuel gas G Gs induced into the space S temporarily remains in the outer region Sk of the tubular member 51, thus increasing the residence time of the fuel gas G in the space S between the inner cylinder 20 and the outer cylinder 10. As a result, the fuel gas G is heated for a longer period of time. These factors further promote the decomposition of tar components in the fuel gas G induced in the space S between the inner cylinder 20 and the outer cylinder 10.

[0031] The sediment T located at the lower end of the sediment section 100, which was used to generate the fuel gas G, is in a carbonized and fluidized state. The discharge promotion section 18 pushes the fluidized sediment T downward and discharges it to the outside of the outer cylinder 10 through the sediment discharge section 16. As the entire accumulation section 100 moves downward, the height of the accumulation section 100 decreases. Sensor 81 continuously detects the height of the accumulation section 100, and when the height of the accumulation section 100 falls below a predetermined height threshold, control unit 80 stops the discharge promotion unit 18 and stops the discharge of the accumulated material T until the height of the accumulation section 100 increases to above the predetermined height threshold due to the continuous supply of biomass raw material F from the biomass raw material supply machine 61. When the height of the accumulation section 100 exceeds the predetermined height threshold, control unit 80 activates the discharge promotion unit 18 and discharges the accumulated material T.

[0032] The biomass gasifier 1 described above indirectly heats and gasifies woody biomass raw material F to produce fuel gas G. The biomass gasifier 1 comprises an outer cylinder 10 with an axis C extending in the vertical direction, an inner cylinder 20 provided inside the outer cylinder 10 with an axis C extending in the vertical direction and its lower end 20b positioned above the lower end 10b of the outer cylinder 10, a reactor 30 that heats the outer cylinder 10 from the outside, and a combustion air supply unit 40 provided inside the inner cylinder 20 to supply combustion air A. The biomass gasifier 1 is provided with a plurality of connecting passages 50 in the space S between the inner cylinder 20 and the outer cylinder 10, extending in the vertical direction so that the upper part SA and the lower part SB of the space S are in communication with each other. The biomass raw material F is supplied from above to the inside of the inner cylinder 20, and fuel gas G is generated from the biomass raw material F. The generated fuel gas G is then guided through multiple connecting passages 50 from bottom to top before being discharged. In this type of biomass gasifier 1, the biomass raw material F is supplied from above to the inside of the inner cylinder 20. The supplied biomass raw material F accumulates inside the inner cylinder 20 to form a deposit section 100. Here, sufficient heat is supplied to the deposit section 100 by a reactor 30 located outside the outer cylinder 10. As a result, fuel gas G is produced from the biomass raw material F. The deposition section 100, where the above-described reaction proceeds, is mainly located inside the inner cylinder 20. The inner cylinder 20 is heated from the outside by the reactor 30, with the outer cylinder 10 in between. As a result, the efficiency of fuel gas G generation is increased in the deposition section 100 inside the inner cylinder 20. Furthermore, since the deposition section 100 is heated and the efficiency of the reaction is increased, the amount of oxygen required for the reaction is reduced. Therefore, the amount of combustion air A supplied from the combustion air supply section 40 can be reduced. As a result, carbon monoxide and hydrogen, which are the main components of the generated fuel gas G, are prevented from being lost due to excessive reaction with oxygen, and the deterioration of the quality of the fuel gas G can be suppressed. Here, the generated fuel gas G passes from the accumulation section 100, through the space between the lower end 20b of the inner cylinder 20 and the lower end 10b of the outer cylinder 10, and is then guided from bottom to top through a plurality of connecting passages 50 provided in the space S between the inner cylinder 20 and the outer cylinder 10 before being discharged. Since a plurality of connecting passages 50 (formed by tubular members 51) are provided in the space S between the inner cylinder 20 and the outer cylinder 10, the number of components heated by the heat supplied from the reactor 30 from the outside of the outer cylinder 10 is greater compared to the case where a plurality of connecting passages 50 are not provided. As a result, the heat transfer area, i.e., the total surface area of ​​the components that heat the fuel gas G by radiant heat transfer, is increased compared to the case where a plurality of connecting passages 50 are not provided, and the fuel gas G is heated more efficiently. As a result, the tar components contained in the fuel gas G can be efficiently decomposed, and high-quality fuel gas G can be efficiently produced.

[0033] Furthermore, multiple tubular members 51 extending in the vertical direction are provided in the space S between the inner cylinder 20 and the outer cylinder 10, and a connecting passage 50 is formed inside the tubular members 51. In this configuration, by providing multiple tubular members 51, multiple communication passages 50 can be easily formed in the space S between the inner cylinder 20 and the outer cylinder 10. Furthermore, the multiple tubular members 51 are heated by the heat supplied from the reactor 30 from the outside of the outer cylinder 10. As a result, the fuel gas G in the space S between the inner cylinder 20 and the outer cylinder 10 can be efficiently heated by radiant heat transfer from the tubular members 51.

[0034] Furthermore, a plate material 53 is provided in the space S between the inner cylinder 20 and the outer cylinder 10, dividing the space S vertically. Multiple tubular members 51 pass through the plate material 53 in the vertical direction and are supported by the plate material 53. In this configuration, by supporting multiple tubular members 51 with the plate material 53, multiple connecting passages 50 can be easily formed in the space S between the inner cylinder 20 and the outer cylinder 10. Furthermore, in portions other than those where multiple tubular members 51 penetrate the plate material 53 vertically, the plate material 53 divides the space S between the inner cylinder 20 and the outer cylinder 10 vertically. As a result, some of the fuel gas G Gs guided into the space S between the inner cylinder 20 and the outer cylinder 10 is guided to the region Sk outside the tubular members 51, and its rise in the space S between the outer cylinder 10 and the inner cylinder 20 is blocked by the plate material 53 provided at the top of the space S between the outer cylinder 10 and the inner cylinder 20. This increases the time that the fuel gas G remains in the space S between the outer cylinder 10 and the inner cylinder 20, and further promotes the decomposition of tar components.

[0035] Furthermore, the inner cylinder 20 and the outer cylinder 10 are each cylindrical in shape and extend in the vertical direction, and the multiple tubular members 51 are arranged around the axis C of the inner cylinder 20 and the outer cylinder 10. In this configuration, multiple tubular members 51 can be efficiently arranged in the space S between the outer cylinder 10 and the inner cylinder 20.

[0036] (Modified example of Embodiment 1) It should be noted that the biomass gasification furnace of the present invention is not limited to the embodiments described above with reference to the drawings, and various modifications are conceivable within its technical scope. For example, in the above embodiment, multiple connecting passages 50 are formed by multiple tubular members 51 arranged concentrically, but the arrangement of the tubular members 51 can be changed as appropriate. Figure 6 shows a modified example of multiple tubular members provided in the space between the inner cylinder and the outer cylinder. As shown in Figure 6, the biomass gasifier 1B of this modified example includes a plurality of first tubular members 51A and a plurality of second tubular members 51B in the space S between the inner cylinder 20 and the outer cylinder 10, as a plurality of tubular members 51 that form a plurality of connecting passages 50B.

[0037] Multiple first tubular members 51A are arranged concentrically, spaced apart in the circumferential direction around the axis C of the inner cylinder 20 and the outer cylinder 10. The multiple second tubular members 51B are provided radially outward from the multiple first tubular members 51A with respect to axis C. The multiple second tubular members 51B are arranged concentrically with spacing in the circumferential direction. The multiple second tubular members 51B are arranged with a phase shift in the circumferential direction relative to the multiple first tubular members 51A. Each second tubular member 51B is positioned between adjacent first tubular members 51A in the circumferential direction. Each second tubular member 51B has a larger diameter than the first tubular member 51A. In this modified example, the multiple first tubular members 51A and the multiple second tubular members 51B are formed to have a circular cross-section. Therefore, each second tubular member 51B has a larger diameter than the first tubular member 51A.

[0038] Thus, in the biomass gasifier 1B of this modified example, the inner cylinder 20 and the outer cylinder 10 are each cylindrical in shape and extend in the vertical direction, and the plurality of tubular members 51 comprises a plurality of first tubular members 51A arranged around the axis C of the inner cylinder 20 and the outer cylinder 10, and a plurality of second tubular members 51B arranged radially outward from the plurality of first tubular members 51A with respect to the axis C. The second tubular members 51B have a larger diameter than the first tubular members 51A. In this configuration, by providing a plurality of first tubular members 51A arranged radially inward and a plurality of second tubular members 51B arranged radially outward in the space S between the inner cylinder 20 and the outer cylinder 10, a larger number of tubular members 51 can be arranged. Moreover, by making the diameter of the second tubular members 51B arranged radially outward larger than the diameter of the first tubular members 51A arranged radially inward, a large number of tubular members 51 can be efficiently arranged within the limited space S between the inner cylinder 20 and the outer cylinder 10. This further increases the total surface area of ​​the component that heats the fuel gas G located in the space S between the inner cylinder 20 and the outer cylinder 10 by radiant heat transfer, allowing the fuel gas G to be heated more efficiently. As a result, the tar components contained in the fuel gas G can be efficiently decomposed, and high-quality fuel gas G can be efficiently produced.

[0039] (Second modified example of the embodiment) In the above embodiment, the multiple connecting passages 50 are formed by multiple tubular members 51, but the invention is not limited to this configuration. Figure 7 shows a modified example of multiple connecting passages provided in the space between the inner cylinder and the outer cylinder. As shown in Figure 7, the biomass gasifier 1C of this modified example is equipped with multiple connecting passages 50C. In this modified example, the multiple connecting passages 50C are formed by partition plates 57. The partition plates 57 are formed in a grid pattern when viewed from above. The partition plates 57 divide the space S between the inner cylinder 20 and the outer cylinder 10 into multiple sections such that each of the multiple connecting passages 50C is approximately rectangular when viewed from above, thereby forming the multiple connecting passages 50C.

[0040] Thus, in the biomass gasification furnace 1C of this modified example, the multiple connecting passages 50C are formed by partitioning the space S between the inner cylinder 20 and the outer cylinder 10 with partition plates 57. In this configuration, by dividing the space S between the inner cylinder 20 and the outer cylinder 10 with a partition plate 57, multiple connecting passages 50C can be formed in the space S between the inner cylinder 20 and the outer cylinder 10. The partition plate 57 is heated by the heat supplied from the reactor 30 from the outside of the outer cylinder 10. By providing the partition plate 57, the total surface area of ​​the members that heat the fuel gas G located in the space S between the inner cylinder 20 and the outer cylinder 10 by radiant heat transfer is increased, and the fuel gas G is heated efficiently. As a result, the tar components contained in the fuel gas G can be efficiently decomposed, and high-quality fuel gas G can be efficiently produced.

[0041] (Third modified example of the embodiment) In the second modified example of the above embodiment, a grid-like partition plate 57 is used to form multiple connecting passages 50C, but the configuration is not limited to this. The configuration of the partition plate 57 can be changed as appropriate. Figure 8 shows another modified example of multiple connecting passages provided in the space between the inner and outer cylinders. As shown in Figure 8, the biomass gasifier 1D of this modified example is equipped with multiple connecting passages 50D. In this modified example, the multiple connecting passages 50D are formed by multiple partition plates 58. When viewed from above, the multiple partition plates 58 are arranged radially between the inner cylinder 20 and the outer cylinder 10, with the axis C of the inner cylinder 20 and the outer cylinder 10 as the center. Each partition plate 58 extends radially between the inner cylinder 20 and the outer cylinder 10. The partition plates 58 divide the space S between the inner cylinder 20 and the outer cylinder 10 into multiple sections in the circumferential direction, thereby forming multiple connecting passages 50D.

[0042] Thus, in the biomass gasifier 1D of this modified example, the multiple connecting passages 50D are formed by partitioning the space between the inner cylinder 20 and the outer cylinder 10 with partition plates 58. In this configuration, by dividing the space S between the inner cylinder 20 and the outer cylinder 10 with a partition plate 58, multiple connecting passages 50D can be formed in the space S between the inner cylinder 20 and the outer cylinder 10. The partition plate 58 is heated by the heat supplied from the reactor 30 from the outside of the outer cylinder 10. By providing the partition plate 58, the total surface area of ​​the members that heat the fuel gas G located in the space S between the inner cylinder 20 and the outer cylinder 10 by radiant heat transfer is increased, and the fuel gas G is heated efficiently. As a result, the tar components contained in the fuel gas G can be efficiently decomposed, and high-quality fuel gas G can be efficiently produced.

[0043] In addition to the above, it is possible to select or replace the configurations listed in the above embodiments, or to change them to other configurations as appropriate, as long as it does not deviate from the spirit of the present invention. [Explanation of Symbols]

[0044] 1, 1B, 1C, 1D Biomass gasification furnace 51B Second tubular member 10 Outer cylinder 53 Plate material 10b Lower end 57, 58 Partition plate 20 Inner cylinder A Combustion air 20b Lower end C axis 30 Reactor F Biomass raw material 40 Combustion air supply unit G Fuel gas 50, 50B, 50C, 50D Connecting passage S Space between the inner and outer cylinders 51 Tubular member SA Upper part of the space between the inner cylinder and the outer cylinder 51A First tubular member SB Lower part of the space between the inner cylinder and the outer cylinder

Claims

1. A biomass gasifier that heats woody biomass raw materials to gasify them and produce fuel gas, An outer cylinder provided so that its axis extends in the vertical direction, Inside the outer cylinder is an inner cylinder provided such that its axis extends vertically and its lower end is located above the lower end of the outer cylinder. A reaction furnace that heats the outer cylinder from the outside, A combustion air supply unit is provided inside the inner cylinder to supply combustion air, Equipped with, The space between the inner cylinder and the outer cylinder is provided with a plurality of connecting passages that extend vertically so that the upper and lower portions of the space are in communication with each other. The biomass raw material is supplied from above into the inner cylinder, and the fuel gas is generated from the biomass raw material. The generated fuel gas is guided through the multiple connecting passages from bottom to top and then discharged. Multiple tubular members extending in the vertical direction are provided in the space between the inner cylinder and the outer cylinder, and the connecting passage is formed inside the tubular members. A plate material is provided in the space between the inner cylinder and the outer cylinder to divide the space vertically. Multiple tubular members penetrate the plate material in the vertical direction and are supported by the plate material. The inner cylinder and the outer cylinder are each cylindrical in shape, extending in the vertical direction. A biomass gasification furnace in which a plurality of the tubular members are arranged at intervals in the circumferential direction around the axes of the inner cylinder and the outer cylinder.

2. A biomass gasifier that heats woody biomass raw material to gasify it and produce fuel gas, An outer cylinder provided so that its axis extends in the vertical direction, Inside the outer cylinder is an inner cylinder provided such that its axis extends vertically and its lower end is located above the lower end of the outer cylinder. A reaction furnace that heats the outer cylinder from the outside, A combustion air supply unit is provided inside the inner cylinder to supply combustion air, Equipped with, The space between the inner cylinder and the outer cylinder is provided with a plurality of connecting passages that extend vertically so that the upper and lower portions of the space are in communication with each other. The biomass raw material is supplied from above into the inner cylinder, and the fuel gas is generated from the biomass raw material. The generated fuel gas is guided through the multiple connecting passages from bottom to top and then discharged. Multiple tubular members extending in the vertical direction are provided in the space between the inner cylinder and the outer cylinder, and the connecting passage is formed inside the tubular members. The inner cylinder and the outer cylinder are each cylindrical in shape, extending in the vertical direction. The multiple tubular members are, A plurality of first tubular members arranged around the axis of the inner cylinder and the outer cylinder, The present invention comprises a plurality of second tubular members arranged radially outward from the plurality of first tubular members with respect to the axis thereof, A biomass gasification furnace wherein the second tubular member has a larger diameter than the first tubular member.

3. A plate material is provided in the space between the inner cylinder and the outer cylinder to divide the space vertically. The biomass gasification furnace according to claim 2, wherein the plurality of tubular members penetrate the plate material in the vertical direction and are supported by the plate material.

Images