Gasification device

Abstract

To provide a gasifier in which a thermal decomposition zone, a combustion zone and a reduction zone are formed during a gasification treatment of wood chips, and to promote combustion of the wood chips stored in the combustion zone.SOLUTION: There is provided a gasifier 1 for gasifying wood chips S, comprising: a reaction vessel 2; a raw material supply path 13; a tapered vessel 20; and a gas supply mechanism 30. The gasifier 1 is configured such that: a thermal decomposition zone T1, a combustion zone T2, and a reduction zone T3 are formed during a gasification treatment of the wood chips S; a lower end of the tapered container 20 is connected to an upper end of the raw material supply path 13; the tapered container 20 has a plurality of slits provided in a region corresponding to the combustion zone T2, and a tapered portion 20a; and the gas supply mechanism 30 has a configuration for supplying combustion promoting gas supplied from an outside of the tapered container 20 to an inside of the tapered container 20 through the slit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gasification device for gasifying wood chips.

Background Art

[0002] In recent years, in order to address issues such as the depletion of fossil fuels, global warming, and the risk of foreign dependence on energy sources, the use of natural energy and renewable energy has been progressing globally. Among renewable energies, there is woody biomass energy made using wood such as thinned wood, which has attracted attention as a new energy in regions with many forest areas such as Japan. Also, woody biomass energy has many merits from the viewpoints of energy self-sufficiency and being an energy that can be stably supplied even in times of emergency.

[0003] As a method for efficiently utilizing such woody biomass energy, woody biomass power generation is known, in which wood chips such as thinned wood are burned as biomass raw materials, and the combustible gas generated thereby is used as a fuel for power generation. As biomass gasification furnaces for gasifying biomass raw materials by burning them, Patent Document 1 and Patent Document 2 disclose furnaces that burn raw materials supplied from the bottom of the furnace and extract combustible gas from the upper part of the furnace.

[0004] Patent Document 1 discloses a gasification apparatus for gasifying wood chips, comprising an input mechanism for introducing semi-carbonized wood chips and a reaction tower for gasifying the wood chips. In this gasification apparatus, three layers are formed from the bottom to the top of the reaction tower: a pyrolysis zone T1, a combustion zone T2, and a reduction zone T3. The pyrolysis zone T1 is the layer where the semi-carbonized wood chips are pyrolyzed; the combustion zone T2 is the layer where the gas produced by pyrolysis is oxidized; and the reduction zone T3 is the layer where the gas produced by pyrolysis is reduced to generate product gases (carbon monoxide and hydrogen) that can be used for power generation. During the gasification process of semi-carbonized wood chips, the heat of combustion generated in the combustion zone T2 is transferred to the pyrolysis zone T1 and the reduction zone T3, thereby promoting the pyrolysis, oxidation, and reduction reactions of the wood chips inside the reaction tower.

[0005] Patent Document 2 discloses a reactor in which a turntable is provided at the bottom of the first gasification stage, and a container for receiving raw materials from below is provided directly above it. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-109907 [Patent Document 2] Special Publication No. 6-031341 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the gasification apparatus described in Patent Document 1, the combustion of wood chips is promoted by supplying a gasifying agent (air and water vapor) into the inside of the reaction tower from a gasifying agent supply pipe (first supply pipe) connected to the bottom of the reaction tower.

[0008] However, when the inventors investigated the flow of the gasifying agent, they found that most of the gasifying agent supplied from the bottom of the reaction tower was consumed in the pyrolysis zone T1, and the gasifying agent did not diffuse sufficiently into the combustion zone T2. As a result, the oxidation reaction in the combustion zone T2 was not promoted, and the temperature in the combustion zone T2 was found to be lower than the target temperature.

[0009] If the temperature of the combustion zone T2 is lower than the target temperature, the amount of heat transferred from the combustion zone T2 to the pyrolysis zone T1 and the reduction zone T3 decreases, causing the temperatures of the pyrolysis zone T1 and the reduction zone T3 to also fall below the target temperature. This makes it more difficult for pyrolysis, oxidation, and reduction reactions to occur inside the reaction tower, resulting in a decrease in the amount of product gas generated per unit time. In this case, the amount of electricity generated by biomass power generation also decreases.

[0010] One possible solution to the above problem is to perform auxiliary heating in the combustion zone T2 to promote the combustion of wood chips in the combustion zone T2. However, continuing auxiliary heating during the gasification process of wood chips leads to a decrease in energy efficiency. Therefore, other means are needed to promote the combustion of wood chips in the combustion zone T2, but no such means existed in conventional technology.

[0011] Furthermore, the reactor described in Patent Document 2 is not a device structure in which three layers are formed: a pyrolysis zone, a combustion zone, and a reduction zone. In other words, Patent Document 2 does not disclose a means for promoting the combustion of wood chips in the combustion zone of a gasification device in which the three layers of pyrolysis zone, combustion zone, and reduction zone described above are formed.

[0012] The present invention has been made in view of the above circumstances, and aims to promote the combustion of wood chips stored in the combustion zone in a gasification apparatus in which a pyrolysis zone, a combustion zone, and a reduction zone are formed during the gasification treatment of wood chips. [Means for solving the problem]

[0013] The present invention, which solves the above problems, is a gasification apparatus for gasifying wood chips, comprising: a reaction vessel in which the wood chips are gasified; a raw material supply passage located at the bottom of the reaction vessel; a tapered vessel provided inside the reaction vessel; and a gas supply mechanism for supplying a combustion-promoting gas to promote the combustion of the wood chips, wherein the gasification apparatus is configured such that a pyrolysis zone, a combustion zone, and a reduction zone are formed during the gasification of the wood chips, the lower end of the tapered vessel is connected to the upper end of the raw material supply passage, and the tapered vessel has a frustoconical or truncated pyramidal tapered section in which the wood chips are stored, and a region provided in the area corresponding to the combustion zone , a hollow gas storage section formed in an annular shape, and formed in the gas storage section The tapered portion has multiple openings, and the cross-sectional area of ​​the tapered portion increases from the lower end to the upper end, and the gas supply mechanism supplies the combustion-promoting gas supplied from the outside of the tapered container, By supplying to the internal space of the gas storage section It is characterized by having a configuration that supplies to the inside of the tapered container through the aforementioned opening.

[0014] The present invention, from another perspective, is a gasification apparatus for gasifying wood chips, comprising: a reaction vessel in which the wood chips are gasified; a raw material supply passage located at the bottom of the reaction vessel; a tapered vessel provided inside the reaction vessel; and a gas supply mechanism for supplying a combustion-promoting gas to accelerate the combustion of the wood chips, wherein the gasification apparatus is configured such that a pyrolysis zone, a combustion zone, and a reduction zone are formed during the gasification of the wood chips, the lower end of the tapered vessel is connected to the upper end of the raw material supply passage, and the tapered vessel has a frustoconical or truncated pyramidal tapered section in which the wood chips are stored, before When H is the height from the bottom to the top of the reaction vessel, within the range of 0.25H to 0.60H It has a hollow gas storage section formed in an annular shape, and a plurality of openings formed in the gas storage section, The tapered portion has an increasing cross-sectional area from the lower end to the upper end, and the gas supply mechanism supplies the combustion-promoting gas from the outside of the tapered container. By supplying to the internal space of the gas storage section It is characterized by having a configuration that supplies to the inside of the tapered container through the aforementioned opening.

[0015] Another aspect of the present invention is a gas treatment method for gasifying wood chips, which uses a gasification device comprising a reaction vessel in which the gasification treatment of the wood chips is carried out and a tapered vessel provided inside the reaction vessel, to form a pyrolysis zone that causes a pyrolysis reaction of the wood chips supplied from below the reaction vessel to the lower end of the tapered vessel, a combustion zone that causes an oxidation reaction of the gas generated from the wood chips, and a reduction zone that causes a reduction reaction of the gas generated from the wood chips, when gasifying the wood chips. before to the combustion zone In the internal space of the annularly formed hollow gas storage section located in the corresponding region supply a combustion promoting gas The combustion-promoting gas is supplied to the combustion zone through a plurality of openings formed in the gas storage section. while gasifying the wood chips.

Advantages of the Invention

[0016] According to the present invention, in a gasification device in which a pyrolysis zone, a combustion zone, and a reduction zone are formed during the gasification treatment of wood chips, the combustion of the wood chips stored in the combustion zone can be promoted.

Brief Description of the Drawings

[0017] [Figure 1] It is an explanatory diagram showing a schematic configuration of a gasification device according to the first embodiment. [Figure 2] It is a perspective view schematically showing the shape of the tapered vessel. [Figure 3] It is a top view of the tapered vessel. [Figure 4] It is a view showing the A-A cross section of FIG. 3. [Figure 5] It is a top view of the tapered vessel for explaining an arrangement example of the openings. [Figure 6] It is a view showing an example of the shape of the openings. [Figure 7] It is a top view of the tapered vessel for explaining the group of openings. [Figure 8] It is a view showing an arrangement example of the openings in the group of openings. [Figure 9] It is a view for explaining the opening angle of the tapered vessel. [[ID=,47]] [Figure 10] It is a view showing an example of the shape of the tapered vessel. [Figure 11] This is an explanatory diagram showing the schematic configuration of a gasification apparatus according to the second embodiment. [Figure 12] This is a top view of a tapered container. [Figure 13] This is a diagram showing the BB cross section in Figure 12. [Figure 14] This is a schematic diagram of a gasification apparatus used in a combustion experiment. [Modes for carrying out the invention]

[0018] Embodiments of the present invention will be described below with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted. The white arrows in the figures indicate the flow of the combustion-promoting gas, which will be described later.

[0019] <First Embodiment> Figure 1 is an explanatory diagram showing the schematic configuration of a gasification apparatus according to the first embodiment. The gasification apparatus 1 according to this embodiment uses wood chips as biomass raw material, and is an updraft type apparatus that gasifies the wood chips by causing thermal decomposition, oxidation, and reduction reactions, and recovers the generated product gas (for example, carbon monoxide or hydrogen) from above. The following is a general description of the configuration of the gasification apparatus 1, but the description of the apparatus configuration may be omitted for parts where the configuration of a known updraft type apparatus can be applied.

[0020] Furthermore, from the viewpoint of increasing the production efficiency of the generated gas obtained by the gasification process, it is preferable that the wood chips are semi-carbonized. Semi-carbonization of wood chips is a process in which the wood chips are heated at a predetermined temperature (200-350°C) in an atmosphere in which water vapor is supplied to a container with a limited or blocked oxygen supply, thereby adjusting the moisture content of the wood chips. Semi-carbonized wood chips have a moisture content of 4-12% by mass, preferably 6-10% by mass, and more preferably 7-9% by mass.

[0021] The gasification apparatus 1 comprises a reaction vessel 2 in which wood chips S are gasified, an insulating material 3 provided on the inner surface of the reaction vessel 2, and a tapered vessel 20 provided inside the insulating material 3. The gasification apparatus 1 also comprises a heater 4 for raising the internal temperature of the reaction vessel 2, a discharge pipe 5 for releasing the generated gas generated inside the reaction vessel 2 to the outside, and a raw material supply mechanism 10 for supplying wood chips S from the bottom of the reaction vessel 2.

[0022] The reaction vessel 2 is a roughly cylindrical, vertical container. Inside this reaction vessel 2, when the wood chips S are gasified, three layers are formed in this order from bottom to top: a pyrolysis zone T1, a combustion zone T2, and a reduction zone T3.

[0023] The shape, material, and size of the reaction vessel 2 and the tapered vessel 20 are not particularly limited, as long as the gasification treatment described later can be carried out. The shape of the reaction vessel 2 is not limited to a cylindrical shape, and may be, for example, a rectangular tube. The size of the reaction vessel 2 may be, for example, 1200 to 1800 mm in total length (height) and 500 to 1800 mm in diameter. The material of the tapered vessel 20 may be, for example, stainless steel, carbon steel, silicon carbide (SiC), brick, etc. From the viewpoint of ease of shaping and heat resistance, it is preferable to use stainless steel as the material of the tapered vessel 20. In addition, the tapered vessel 20 may be coated, for example, with a calorifying treatment on its inner surface.

[0024] The pyrolysis zone T1 described above is a layer where the pyrolysis reaction of wood chips S occurs due to heat received from the combustion zone T2. The combustion zone T2 is a layer where the wood chips S undergo an oxidation reaction, supplying heat to the pyrolysis zone T1 and the reduction zone T3. The reduction zone T3 is a layer where the reduction reaction of gases generated from wood chips S occurs due to heat received from the combustion zone T2, producing product gases such as carbon monoxide and hydrogen gas.

[0025] During the gasification process, the temperature of the pyrolysis zone T1 is, for example, less than 450°C, the temperature of the combustion zone T2 is, for example, 450 to 600°C, and the temperature of the reduction zone T3 is, for example, 650°C or higher. However, from the viewpoint of increasing the production efficiency of the generated gas, it is preferable that the temperature of the reduction zone T3 during the gasification process be 800°C or lower.

[0026] The thermal insulation material 3 is provided as needed, depending on the shape of the reaction vessel 2 and the tapered vessel 20. In this embodiment, it is placed on the entire ceiling surface 2a and side surface 2b of the reaction vessel 2, and on a portion of the bottom surface 2c. Below the thermal insulation material 3, an inclined portion 3a is formed in the part facing the tapered portion 20a of the tapered vessel 20, which will be described later, and the inclined portion 3a of the thermal insulation material 3 and the tapered portion 20a of the tapered vessel 20 are in a substantially parallel state. These inclined portions 3a and the tapered portion 20a are not in contact with each other and are spaced apart. In addition, a flat portion 3b is formed at the upper end of the inclined portion 3a of the thermal insulation material 3, on which the annular flat portion 20b of the tapered vessel 20, which will be described later, rests.

[0027] Heater 4 is a device that raises the internal temperature of the reaction vessel 2 to a predetermined temperature (e.g., 450-600°C) when the gasification process of wood chips S is started, raising the temperature of the combustion zone T2 to a predetermined temperature. Heater 4 stops after the combustion zone T2 reaches the predetermined temperature. The heat source for the subsequent gasification process is the heat of combustion generated by the oxidation reaction in the combustion zone T2, and this heat of combustion is transferred to the pyrolysis zone T1 and the reduction zone T3. As a result, the pyrolysis reaction of the wood chips S supplied to the reaction vessel 2, and the oxidation and reduction reactions of the gas produced from the wood chips S proceed automatically.

[0028] In this specification, the pyrolysis, oxidation, and reduction reactions are those represented by the following reaction equations.

[0029] [ka]

[0030] The heater 4 is just one example of a means for raising the temperature of the combustion zone T2. Therefore, if the combustion zone T2 can be heated by other means, such as known heating means, the heater 4 does not need to be provided. For example, instead of the heater 4, an ignition device (not shown) for igniting the wood chips S in the combustion zone T2 may be provided.

[0031] The discharge pipe 5 is a pipe for releasing product gases (such as carbon monoxide and hydrogen) generated inside the reaction vessel 2 to the outside, and is located at the top of the reaction vessel 2. The product gases released from the discharge pipe 5 are sent to a product gas storage unit (not shown) and used, for example, as fuel for biomass power generation.

[0032] The raw material supply mechanism 10 includes an input section 11 into which wood chips S are fed, a transport path 12 for transporting the wood chips S fed into the input section 11, and a raw material supply path 13 for supplying the wood chips S transported by the transport path 12 to the bottom of the reaction vessel 2.

[0033] The input section 11 has a hopper 14 and an input passage 15 connected to the lower end of the hopper 14. The input passage 15 is shaped to extend in the height direction of the reaction vessel 2, and the wood chips S that have been fed into the hopper 14 are stored inside the input passage 15. The transport passage 12 is shaped to extend horizontally and is connected to the lower end of the input passage 15. The raw material supply passage 13 is shaped to extend in the height direction of the reaction vessel 2, and a supply port (not shown) for supplying wood chips S toward the reaction vessel 2 is formed on the upper surface of the raw material supply passage 13. Screws 16 and 17 are provided inside the transport passage 12 and the raw material supply passage 13, respectively, and are rotated by a rotational drive source such as a motor.

[0034] According to the raw material supply mechanism 10 with the above configuration, the wood chips S fed into the input section 11 are transported to the raw material supply path 13 via the transport path 12, and the wood chips S are pushed upward by the screw 17 inside the raw material supply path 13.

[0035] Next, the tapered container 20 according to this embodiment will be described. Figure 2 is a schematic perspective view showing the shape of the tapered container. Figure 3 is a top view of the tapered container. Figure 4 is a view of cross-section AA of Figure 3. Note that the thermal insulation material 3 is not shown in Figure 4.

[0036] The tapered container 20 is a container having a frustoconical tapered portion 20a, with the upper and lower ends of the tapered container 20 being open. The tapered portion 20a is formed so that its diameter increases from the lower end to the upper end. In other words, the tapered portion 20a is formed so that its cross-sectional area (the area of ​​the cross-section perpendicular to the axis C of the tapered container 20) increases from the lower end to the upper end.

[0037] As shown in Figures 3 and 4, an annular flat portion 20b is formed at the upper end of the tapered portion 20a. A wall portion 20c is formed around the periphery of the annular flat portion 20b, which is parallel to the axis C of the tapered container 20 and extends upward. As shown in Figure 1, the annular flat portion 20b of the tapered container 20 rests on the flat portion 3b of the insulation material 3, and the wall portion 20c of the tapered container 20 is in contact with the inner surface of the side wall of the insulation material 3.

[0038] The lower end of the tapered section 20a protrudes downward from the bottom surface 2c of the reaction vessel 2 and is connected to the upper end of the raw material supply passage 13. As a result, the wood chips S supplied from the raw material supply passage 13 are supplied from the lower end of the tapered section 20a, filling the inside of the tapered vessel 20 with wood chips S. During the gasification process, the screws 16 and 17 rotate in a constant cycle, and a constant amount of wood chips S is continuously supplied per unit time.

[0039] Preferably, the inner diameter of the lower end of the tapered section 20a is the same as the inner diameter of the upper end of the raw material supply passage 13. This allows the wood chips S supplied from the raw material supply passage 13 to the tapered section 20a to be pushed upward without accumulating within the tapered section 20a. For example, if the inner diameter of the lower end of the tapered section 20a is larger than the inner diameter of the upper end of the raw material supply passage 13, a bottom surface must be provided at the lower end of the tapered section 20a, resulting in a corner between the bottom surface and the lower end of the tapered section. In that case, the wood chips S supplied into the tapered section will accumulate in the corner, causing a disturbance in the temperature distribution around the accumulated wood chips S. Therefore, to prevent the formation of such a corner, it is preferable that the inner diameter of the lower end of the tapered section 20a is the same as the inner diameter of the upper end of the raw material supply passage 13.

[0040] As shown in Figures 3 and 4, the tapered container 20 has an opening 21. This opening 21 is formed at the height of the region corresponding to the combustion zone T2 formed during the gasification process of the wood chips S. The size of each layer, the pyrolysis zone T1, the combustion zone T2, and the reduction zone T3, varies depending on the apparatus configuration, such as the shape of the reaction vessel 2 and the shape of the tapered container 20. However, a person skilled in the art can estimate the size of each layer from the configuration of the gasification apparatus. In other words, a person skilled in the art can determine whether or not the opening in a gasification apparatus having a tapered container with an opening is formed at the height of the region corresponding to the combustion zone T2.

[0041] As described above, the region where the combustion zone T2 is formed varies depending on the configuration of the gasification apparatus, but the opening 21 is formed within the range of 0.25H (0.25 × H) to 0.60H (0.60 × H), where H is the height from the bottom surface 2c to the top surface 2a inside the reaction vessel 2. In other words, the region from the lower end to the upper end of the opening 21 is located within the range of 0.25H to 0.60H. Furthermore, the opening 21 formed within this numerical range is located at the height of the combustion zone T2 formed during the gasification process.

[0042] The above numerical range is preferably 0.55H or less, and more preferably 0.50H or less.

[0043] The opening 21 in this embodiment is a slit 21a. This slit 21a is formed near the upper end of the tapered portion 20a and extends radially in the tapered portion 20a in the top view of the tapered container 20 shown in Figure 3, straddling the boundary between the tapered portion 20a and the annular planar portion 20b.

[0044] Multiple slits 21a are provided at intervals in the circumferential direction of the tapered container 20. From the viewpoint of more uniform combustion of the wood chips S in the combustion zone T2, the angle θ1 between the centerlines (centerlines in the long axis direction) of two adjacent slits 21a is preferably 5 to 90°, and more preferably 5 to 30°. If the wood chips S in the combustion zone T2 can be burned uniformly, the thermal decomposition reaction, oxidation reaction, and reduction reaction in the reaction vessel 2 can be stabilized, and it becomes easier to maintain the raw material temperature and atmosphere temperature in the reaction vessel 2 within a predetermined temperature range.

[0045] The number of slits 21a can be appropriately changed depending on the angle θ1 set between the centerlines of two adjacent slits 21a. Also, as shown in Figure 5, adjacent slits 21a in the circumferential direction of the tapered container 20 may be arranged in a staggered pattern such that their positions in the radial direction of the tapered container 20 are different from each other. Furthermore, the shape of the slits 21a is not limited to the shape described in this embodiment. For example, the slits 21a may be formed in an arc shape along the circumferential direction of the tapered container 20.

[0046] Furthermore, the opening 21 is not limited to the slit 21a, but can be any hole with a shape that prevents the wood chips S stored in the tapered container 20 from falling out of the opening 21. For example, the opening 21 may be a round hole as shown in Figure 6(a), a square hole as shown in Figure 6(b), or a zigzag hole as shown in Figure 6(c). Alternatively, the opening 21 may be a hole with a shape in which the width gradually decreases from the lower end to the upper end of the opening 21, as shown in Figure 6(d), or a hole with a shape in which the width gradually increases from the lower end to the upper end of the opening 21, as shown in Figure 6(e).

[0047] Furthermore, as shown in Figure 7, a group of openings G can be provided by arranging multiple openings 21 in a straight line. It is presumed that such a group of openings G functions similarly to the slit 21a described above.

[0048] The group of openings G shown in Figure 7 extends radially along the tapered portion 20a in a top view of the tapered portion 20a and is arranged in multiples at intervals along the circumferential direction of the tapered portion 20a. In this example, as with the slit 21a described above, from the viewpoint of burning the wood chips S more uniformly, the angle θ1 between the centerlines of two adjacent slits 21a (straight lines connecting the centers of the holes in each opening 21) is preferably 5 to 90°, and more preferably 5 to 30°.

[0049] In addition, the opening group G shown in Figure 7 has the round holes 21b as openings 21 arranged in a straight line as shown in Figure 8(a). However, as shown in Figure 8(b), the round holes 21b may be arranged in a staggered pattern within the opening group G. That is, each opening 21 included in the opening group G does not have to be arranged in a strictly straight line, and the "opening group G formed by the arrangement of openings 21 in a straight line" also includes the form in which the openings 21 are arranged as shown in Figure 8(b). Furthermore, the shape of the openings 21 included in the opening group G is not limited to round holes 21b. Moreover, multiple opening groups G may be arranged in a staggered pattern as shown in Figure 5.

[0050] As shown in Figure 9, the opening angle θ2 of the tapered portion 20a of the tapered container 20 is preferably 90° or less. The lower limit of the opening angle θ2 is not particularly limited, but from the viewpoint of increasing the storage space for wood chips S in the tapered container 20 and increasing the amount of production gas generated, the opening angle θ2 is preferably 30° or more. The opening angle θ2 is the angle between opposing tapered portions 20a in the cut surface when the tapered container 20 is cut along the axis C.

[0051] Furthermore, the shape of the tapered portion 20a is not limited to a frustoconical shape, but may also be a frustoconical shape such as a frustoconical pyramid. Also, as shown in Figure 10, the formation position of the tapered portion 20a does not have to be at the lower end of the tapered container 20.

[0052] Next, we will describe the gas supply mechanism 30 that supplies a combustion-accelerating gas to the wood chips S stored in the combustion zone T2. The combustion-accelerating gas is, for example, air, but the type of gas is not particularly limited as long as it can accelerate the combustion of the wood chips S.

[0053] The gas supply mechanism 30 includes a gas supply source 31, such as a gas cylinder, which is a source of combustion-promoting gas; piping 32 connected to the gas supply source 31; and a gas supply pipe 33 connected to the piping 32.

[0054] Multiple gas supply pipes 33 are provided along the circumferential direction of the reaction vessel 2 and are connected to the bottom of the reaction vessel 2. The combustion-accelerating gas supplied from these gas supply pipes 33 is supplied to the inside of the reaction vessel 2 and to the outside of the tapered vessel 20. In this embodiment, a gap is formed between the inclined portion 3a of the heat insulating material 3 and the tapered portion 20a of the tapered vessel 20, and this gap becomes the gas flow path 34 for the combustion-accelerating gas.

[0055] The gas flow path 34 extends from the connection point between the reaction vessel 2 and the gas supply pipe 33 to the formation location of the slit 21a. This gas flow path 34 is an annular space formed along the outer surface of the tapered portion 20a, and the combustion-accelerating gas supplied from the gas supply pipe 33 flows through this space. From this space, the combustion-accelerating gas is supplied from the outside to the inside of the tapered container 20 through the slit 21a. As mentioned above, since the slit 21a is formed in the region corresponding to the combustion zone T2 of the tapered container 20, the combustion-accelerating gas passing through the slit 21a is supplied to the wood chips S stored in the combustion zone T2.

[0056] The gas supply mechanism 30 has been described above, but the configuration of the gas supply mechanism 30 is not limited to the configuration described in this embodiment. For example, the gas supply pipe 33 may be connected to the side wall of the reaction vessel 2. Even in this case, if the combustion-accelerating gas can be supplied from the gas supply pipe 33 to the gas flow path 34, the combustion-accelerating gas can be supplied to the combustion zone T2 via the slit 21a.

[0057] As shown in Figure 1, a temperature sensor 40 for measuring the temperature of the combustion zone T2 is provided on the side wall of the reaction vessel 2. This temperature sensor 40 monitors the temperature of the combustion zone T2 during the gasification process. Although not shown in the figure, the gasification apparatus 1 is equipped with various sensors, including temperature sensors for measuring the temperatures of the pyrolysis zone T1 and the reduction zone T3, and sensors for measuring the amount of wood chips S stored in the tapered container 20.

[0058] The gasification apparatus 1 includes a control unit 100 that controls the raw material supply mechanism 10, the gas supply mechanism 30, and the like. The control unit 100 is, for example, a computer equipped with a CPU and memory, and has a program storage unit (not shown). The program storage unit stores various programs that control the gasification process in the gasification apparatus 1 based on information obtained from various sensors. Note that the above programs may have been recorded on a storage medium readable by the computer and installed from that storage medium to the control unit 100.

[0059] The control unit 100 controls the flow rate of the combustion-accelerating gas based on the temperature of the combustion zone T2 measured by the temperature sensor 40. For example, if the measured temperature of the combustion zone T2 falls below the target temperature, the opening of the valve of the gas supply source 31 is adjusted based on the control signal output by the control unit 100, and the flow rate of the combustion-accelerating gas increases.

[0060] Furthermore, when the combustion accelerating gas is air, the control unit 100 controls the amount of air supplied so that the air ratio (A1 / A0) between the amount of air A1 supplied to oxidize the wood chips S in the reaction vessel 2 and the theoretical amount of air A0 required to completely oxidize the wood chips S in the reaction vessel 2 is between 0.40 and 0.90. When calculating the theoretical amount of air A0, the carbon content and hydrogen content of the wood chips S used are measured in advance, and these measured values ​​are used to calculate the theoretical amount of air A0.

[0061] In the above example, the control unit 100 automatically adjusts the amount of air supplied to the reaction vessel 2, but this automatic adjustment is not required. For example, the amount of air may be set so that the air ratio (A1 / A0) is between 0.40 and 0.90 based on the set value of the raw material input amount, and this set amount of air may be continuously supplied during the gasification process.

[0062] The air-fuel ratio (A1 / A0) is preferably 0.45 or higher, and more preferably 0.50 or higher.

[0063] The gasification apparatus 1 according to this embodiment has been described above. In this gasification apparatus 1, a slit 21a is formed in the region of the tapered container 20 corresponding to the combustion zone T2, and a combustion-promoting gas can be locally supplied to the combustion zone T2 through the slit 21a. As a result, the combustion of wood chips S in the combustion zone T2 is promoted, and the supply of heat from the combustion zone T2 to the pyrolysis zone T1 and the reduction zone T3 can be stabilized. This suppresses temperature fluctuations in each layer of the pyrolysis zone T1, combustion zone T2, and reduction zone T3 during the gasification process, and the pyrolysis reaction of wood chips S and the oxidation and reduction reactions of the gas produced from wood chips S occur stably. As a result, the amount of generated gas can be increased, and the amount of power generated by biomass power generation can also be increased.

[0064] Furthermore, since the combustion zone T2 can be heated by supplying a combustion-accelerating gas to it, the auxiliary heater for heating the combustion zone T2 that is required in conventional gasification devices is unnecessary. In other words, the gasification device 1 according to this embodiment makes it possible to improve energy efficiency and increase the power generation efficiency in biomass power generation.

[0065] <Second Embodiment> Figure 11 is an explanatory diagram showing the schematic configuration of the gasification apparatus 1 according to the second embodiment. Figure 12 is a top view of the tapered container. Figure 13 is a diagram showing the BB cross section of Figure 12. Note that the parts of the configuration of the gasification apparatus 1 according to this embodiment that are the same as those of the gasification apparatus described in the first embodiment will not be explained.

[0066] The tapered container 20 according to this embodiment has a hollow gas storage section 22 formed in an annular shape. The gas storage section 22 is provided in a region corresponding to the combustion zone T2, and in this embodiment, the gas storage section 22 is provided on the annular planar section 20b of the tapered container 20. Note that the cross-sectional shape of the gas storage section 22 is not limited to a rectangular shape as in this embodiment.

[0067] A slit 21a extending in the height direction of the tapered container 20 is formed as an opening 21 on the inner circumferential surface of the gas storage section 22, and multiple slits 21a are provided at intervals along the circumferential direction of the tapered container 20. These slits 21a are located at the height of the region corresponding to the combustion zone T2, as in the first embodiment. More specifically, as in the first embodiment, the slits 21a are formed in the range of 0.25H to 0.60H, where H is the height from the bottom surface 2c to the top surface 2a inside the reaction vessel 2.

[0068] In this embodiment, when the combustion-promoting gas is supplied horizontally to the combustion zone T2, the above numerical range is preferably 0.27H or higher, more preferably 0.30H or higher, and even more preferably 0.35H or higher. On the other hand, the above numerical range is preferably 0.55H or lower, and more preferably 0.50H or lower.

[0069] The gas supply pipe 33, which supplies the combustion-accelerating gas, is connected to the gas storage section 22. Therefore, when the combustion-accelerating gas is supplied from the gas supply pipe 33, the combustion-accelerating gas flows into the gas storage section 22 and diffuses into the internal space of the gas storage section 22. When the gas storage section 22 is filled with the combustion-accelerating gas and the internal pressure of the gas storage section 22 becomes sufficiently large, the combustion-accelerating gas is ejected through the slit 21a toward the combustion zone T2.

[0070] In the gasification apparatus 1 according to this embodiment, the combustion-accelerating gas supplied from the gas supply pipe 33 fills the gas storage section 22, and the combustion-accelerating gas is ejected from the slit 21a due to the difference between the internal pressure and external pressure of the gas storage section 22. As a result, the flow rate of the combustion-accelerating gas ejected from the slit 21a tends to be uniform in the circumferential direction of the tapered container 20. In other words, the wood chips S can be burned more uniformly in the combustion zone T2.

[0071] Although embodiments of the present invention have been described above, the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these will naturally also fall within the technical scope of the present invention.

[0072] For example, the means for locally supplying a combustion-promoting gas to the combustion zone T2 may be realized by combining the configuration described in the first embodiment and the configuration described in the second embodiment. [Examples]

[0073] A combustion experiment of wood chips was conducted using the experimental furnace 1 shown in Figure 14. The experimental furnace 1 has a configuration corresponding to the gasification apparatus in the first embodiment described above.

[0074] Specifically, a frustoconical tapered vessel 20 is provided inside a cylindrical reaction vessel 2, and the lower end of the tapered vessel 20 is connected to the upper end of the raw material supply passage 13. A slit 21a is also formed to supply air, which is supplied as a combustion-accelerating gas from the bottom of the reaction vessel 2, to the inside of the tapered vessel 20 from the upper end of the tapered vessel 20. This slit 21a is provided in the region of the tapered vessel 20 corresponding to the combustion zone T2. More specifically, when the height from the bottom to the top of the reaction vessel 2 is H, the lower end of the slit 21a is formed at a height of 0.30H, and the upper end of the slit 21a is formed at a height of 0.39H.

[0075] Furthermore, thermocouple-type temperature sensors TR1 to TR4 are installed on the side wall of the reaction vessel 2. Temperature sensor TR1 measures the temperature of the pyrolysis zone during the combustion experiment, temperature sensors TR2 and TR3 measure the temperature of the combustion zone during the combustion experiment, and temperature sensor TR4 measures the temperature of the reduction zone during the combustion experiment.

[0076] The combustion experiment was conducted as follows: First, wood chips were supplied at a rate of 2.6 kg / h while the heater was operated until the temperature measured by the temperature sensor TR4 reached 700°C. After the temperature reached 700°C, the heater was stopped, and the temperature change was monitored for the following 90 minutes. During the combustion experiment, air was supplied to the slit 21a so that the air ratio (A1 / A0) of the amount of air A1 supplied to oxidize the wood chips in the reaction vessel to the theoretical amount of air A0 required to completely oxidize the wood chips was 0.50. The results of the combustion experiment conducted under these conditions are shown in Table 1 below.

[0077] [Table 1]

[0078] As shown in Table 1, the average temperature of the pyrolysis zone measured by temperature sensor TR1, the average temperature of the combustion zone measured by temperature sensors TR2 and TR3, and the average temperature of the reduction zone measured by temperature sensor TR4 are all within ±30°C of the target temperature. This result indicates that the pyrolysis, oxidation, and reduction reactions in the reaction vessel are stably occurring due to the enhanced supply of air to the combustion zone. [Industrial applicability]

[0079] This invention can be applied to the gasification treatment of wood chips. [Explanation of symbols]

[0080] 1. Gasification device 2. Reaction vessel 2a Ceiling surface 2b side 2c Bottom 3. Insulation 3a Slope 3b Plane part 4 Heaters 5 Release tube 10 Raw material supply mechanism 11 Input section 12 Conveyor paths 13 Raw material supply route 14 Hopper 15 Input route 16 Screw 17 Screw 20 Tapered containers 20a Tapered section 20b Annular planar section 20c wall section 21 Opening 21a Slit 21b Round hole 22 Gas storage section 30 Gas supply mechanism 31 Gas supply sources 32 Piping 33 Gas supply pipe 34 Gas flow path 40 Temperature Sensors 100 Control Unit C Tapered container axis G opening group S Wood chips θ1 Slit spacing angle Opening angle of θ2 tapered container

Claims

1. A gasification device that gasifies wood chips, A reaction vessel in which the wood chips are subjected to gasification treatment, A raw material supply passage located at the bottom of the reaction vessel, A tapered vessel provided inside the reaction vessel, The system includes a gas supply mechanism that supplies a combustion-promoting gas to accelerate the combustion of the wood chips, The gasification apparatus is configured such that a pyrolysis zone, a combustion zone, and a reduction zone are formed during the gasification process of the wood chips. The lower end of the tapered container is connected to the upper end of the raw material supply path. The aforementioned tapered container is The aforementioned wood chips are stored in a frustoconical or truncated pyramidal tapered section, A hollow, annular gas storage section is provided in the region corresponding to the combustion zone, The gas storage section has a plurality of openings formed therein, The tapered portion has an increasing cross-sectional area from the lower end to the upper end. The gas supply mechanism is configured to supply the combustion-promoting gas supplied from the outside of the tapered container to the internal space of the gas storage section and then to the inside of the tapered container through the opening, in a gasification device.

2. A gasification device that gasifies wood chips, A reaction vessel in which the wood chips are subjected to gasification treatment, A raw material supply passage located at the bottom of the reaction vessel, A tapered vessel provided inside the reaction vessel, The system includes a gas supply mechanism that supplies a combustion-promoting gas to accelerate the combustion of the wood chips, The gasification apparatus is configured such that a pyrolysis zone, a combustion zone, and a reduction zone are formed during the gasification process of the wood chips. The lower end of the tapered container is connected to the upper end of the raw material supply path. The aforementioned tapered container is The aforementioned wood chips are stored in a frustoconical or truncated pyramidal tapered section, When the height from the bottom to the top of the reaction vessel is H, a hollow, annular gas storage section is provided within the range of 0.25H to 0.60H, The gas storage section has a plurality of openings formed therein, The tapered portion has an increasing cross-sectional area from the lower end to the upper end. The gas supply mechanism is configured to supply the combustion-promoting gas supplied from the outside of the tapered container to the internal space of the gas storage section and then to the inside of the tapered container through the opening, in a gasification device.

3. The tapered container has an annular flat portion at the upper end of the tapered portion, The gasification apparatus according to claim 1 or 2, wherein the gas storage section is arranged on the annular planar section.

4. The gasification apparatus according to any one of claims 1 to 3, wherein the opening angle of the tapered portion is 30 to 90°.

5. The tapered portion is formed in the shape of a frustocone, The aforementioned opening is a slit, The gasification apparatus according to any one of claims 1 to 4, wherein the slits, when viewed from above, extend in the radial direction of the tapered portion and are formed at intervals along the circumferential direction of the tapered portion.

6. The gasification apparatus according to claim 5, wherein the angle between the centerlines of two adjacent slits in the circumferential direction of the tapered portion is 5 to 90°.

7. The group of openings is formed by arranging the plurality of openings in a straight line, The tapered portion is formed in the shape of a frustocone, The gasification apparatus according to any one of claims 1 to 4, wherein the group of openings extends radially in the tapered portion and is formed at intervals along the circumferential direction of the tapered portion when viewed from above.

8. The gasification apparatus according to claim 7, wherein the angle between the centerlines of two adjacent groups of openings in the circumferential direction of the tapered portion is 5 to 90°.

9. The system includes a control unit that controls the gas supply mechanism, The aforementioned combustion-accelerating gas is air. The control unit supplies the amount of air A to oxidize the wood chips in the reaction vessel. 1 And the theoretical amount of air A required to completely oxidize the wood chips in the reaction vessel. 0 The air ratio (A 1 / A 0 The gasification apparatus according to any one of claims 1 to 8, configured to perform control of supplying the combustion-promoting gas such that the ratio is 0.40 to 0.

90.

10. A gas treatment method for gasifying wood chips, A reaction vessel in which the wood chips are subjected to gasification treatment, Using a gasification apparatus equipped with a tapered vessel provided inside the reaction vessel, A thermal decomposition zone that causes the thermal decomposition reaction of the wood chips supplied from below the reaction vessel to the lower end of the tapered vessel, A combustion zone that causes an oxidation reaction of the gas generated from the aforementioned wood chips, When gasifying the wood chips by forming a reduction zone that causes a reduction reaction of the gas generated from the wood chips, A gasification method comprising supplying a combustion-accelerating gas to the internal space of a hollow, annularly formed gas storage section provided in a region corresponding to the combustion zone, and gasifying the wood chips while supplying the combustion-accelerating gas to the combustion zone through a plurality of openings formed in the gas storage section.

11. The aforementioned combustion-accelerating gas is air. Amount of air A supplied to oxidize the wood chips in the reaction vessel. 1 And the theoretical amount of air A required to completely oxidize the wood chips in the reaction vessel. 0 The air ratio (A 1 / A 0 The gasification treatment method according to claim 10, wherein the combustion-promoting gas is supplied such that the ratio is 0.40 to 0.90.

Images