Gasifier and gasification treatment method

Abstract

To improve accuracy of flow control of firing promotion gas supplied to a wood chip.SOLUTION: A gasifier 1 for gasification of a wood chip S is provided with a reaction container 2 where gasification treatment of the wood chip S is conducted, a raw material supply passage 13 disposed at a bottom of the reaction container 2, a raw material storage container 3 to which the wood chip S is supplied from the raw material supply passage 13, a gas feed mechanism 20 to supply a firing promotion gas for promotion of firing of the wood chip S to the raw material storage container 3, a temperature measurement unit 7a for measuring an atmospheric temperature in the reaction container 2, and a control unit 100 for controlling operation of the gas feed mechanism 20. The control unit 100 is constituted so as to execute a control for regulating a flow rate of a firing promotion gas to adjust the atmospheric temperature measured by the temperature measurement unit 7a to a temperature within an objective temperature range.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gasification apparatus and a gasification method for gasifying wood chips. [Background technology]

[0002] In recent years, the use of natural and renewable energy has been increasing worldwide to address issues such as the depletion of fossil fuels, global warming, and the risk of dependence on foreign energy sources. One type of renewable energy is wood biomass energy, which is produced using wood from thinnings and other sources, and is attracting attention as a new form of energy in areas with many forests, such as Japan. Wood biomass energy also offers many benefits in terms of energy self-sufficiency and the ability to provide a stable supply of energy even in emergencies.

[0003] As a method for efficiently utilizing wood biomass energy, wood biomass power generation is known, in which wood chips such as thinned wood are burned as a biomass raw material and the resulting combustible gas is used as fuel for power generation.

[0004] As an apparatus for burning the above-mentioned wood chips to generate gas to be used for power generation, etc., there is a gasification apparatus described in Japanese Patent Application No. 2022-012248 (hereinafter referred to as "Reference 1"). This gasification apparatus is configured to form a pyrolysis zone T1 in which a pyrolysis reaction of the wood chips occurs, a combustion zone T2 in which an oxidation reaction of the gas generated from the wood chips occurs, and a reduction zone T3 in which a reduction reaction of the gas generated from the wood chips occurs in a reaction vessel in which the wood chips are gasified. Note that the gasification apparatus described in Reference 1 is a non-publicly known technology at the time of filing this application.

[0005] In order to facilitate the occurrence of the above-mentioned pyrolysis, oxidation, and reduction reactions, it is desirable to maintain the temperatures of the pyrolysis zone T1, combustion zone T2, and reduction zone T3 within appropriate temperature ranges. For this reason, in the gasification apparatus described in Reference 1, a combustion promotion gas for promoting the combustion of wood chips is supplied to the combustion zone T2, and the flow rate of the combustion promotion gas is adjusted based on the temperature of the combustion zone T2. In this way, an attempt is made to maintain the combustion zone T2 at an appropriate temperature and to maintain the temperatures of the pyrolysis zone T1 and reduction zone T3, to which the heat generated in the combustion zone T2 is transferred, at appropriate temperatures. Summary of the Invention [Problem to be solved by the invention]

[0006] In the pile of wood chips fed into the reaction vessel of the gasifier, the state of the wood chips changes as the gasification process progresses due to temperature rise, drying, pyrolysis, oxidation, and reduction reactions. In addition, the height of the pile of wood chips in the reaction vessel increases and decreases due to the gasification of the wood chips and the supply of untreated wood chips into the reaction vessel. During the gasification process, these factors cause the temperature of the combustion zone T2 to fluctuate unstably.

[0007] For this reason, if the flow rate of the combustion promotion gas is controlled using the temperature of the combustion zone T2, which changes unstably, as an index, it is difficult to adjust the flow rate of the combustion promotion gas to an appropriate flow rate. Furthermore, the inability to supply the combustion promotion gas at an appropriate flow rate is an external factor that further destabilizes the reaction occurring in the combustion zone T2, and the temperature of the combustion zone T2 during the gasification process becomes even more unstable. This makes it even more difficult to control the flow rate of the combustion promotion gas using the temperature of the combustion zone T2 as an index, and it is difficult to accurately adjust the flow rate of the combustion promotion gas to an appropriate value.

[0008] The present invention has been made in consideration of the above circumstances, and has an object to improve the accuracy of flow rate adjustment of combustion promoting gas supplied to wood chips. [Means for solving the problem]

[0009] The aspects of the present invention that solve the above problems are exemplified below. (1) A gasification device for gasifying wood chips, comprising: A reaction vessel in which the wood chips are gasified; A raw material supply channel disposed at the bottom of the reaction vessel; a raw material storage container provided inside the reaction container and receiving the wood chips from the raw material supply passage; a gas supply mechanism that supplies a combustion promoting gas that promotes combustion of the wood chips into the raw material storage container; a temperature measuring unit provided above an upper end of the raw material storage container and measuring an atmospheric temperature in the reaction container; A control unit that controls the operation of the gas supply mechanism, The control unit is A gasification apparatus, characterized in that a control is performed to adjust the flow rate of the combustion promotion gas so that the atmospheric temperature measured by the temperature measuring unit is within a target temperature range. (2) The gas supply mechanism includes: An inverter capable of variable frequency control; a blower that blows the combustion promotion gas at an air volume corresponding to a set frequency of the inverter, The control unit is The gasification apparatus according to (1), characterized in that a control is performed to adjust the set frequency of the inverter so that the atmospheric temperature measured by the temperature measuring unit is within a target temperature range. (3) A gasification treatment method using a gasification apparatus for gasifying wood chips, comprising the steps of: The gasification apparatus comprises: A reaction vessel in which the wood chips are gasified; A raw material supply channel disposed at the bottom of the reaction vessel; a raw material storage container provided inside the reaction container and receiving the wood chips from the raw material supply passage; During the gasification process, A combustion promoting gas for promoting combustion of the wood chips is supplied into the raw material storage container; A gasification processing method, characterized in that the atmospheric temperature in the reaction vessel is measured above the upper end of the raw material storage vessel, and the flow rate of the combustion promotion gas is adjusted so that the measured atmospheric temperature is within a target temperature range. (4) The gasification apparatus comprises: An inverter capable of variable frequency control; a blower that blows the combustion promotion gas at an air volume corresponding to a set frequency of the inverter, The gasification treatment method according to (3), characterized in that, when performing the gasification treatment, the set frequency of the inverter is adjusted so that the measured atmospheric temperature falls within a target temperature range. Effect of the Invention

[0010] According to the present invention, it is possible to improve the accuracy of adjusting the flow rate of the combustion promoting gas supplied to the wood chips. [Brief description of the drawings]

[0011] [Figure 1] 1 is an explanatory diagram showing a schematic configuration of a gasification apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing a schematic configuration of a gasification apparatus used in a combustion experiment. [Diagram 3] 1 is a graph showing changes over time in temperature measured by a temperature sensor. [Figure 4] 1 is a graph showing changes over time in temperature measured by a temperature sensor and in the input frequency to the blower when the blower is operated with ON / OFF control. [Diagram 5] 1 is a graph showing the change over time in the calorific value of generated gas when the blower is operated with ON / OFF control. [Figure 6] 1 is a graph showing changes over time in temperature measured by a temperature sensor and in the input frequency to the blower when the blower is operated under frequency control. [Figure 7] 1 is a graph showing the change over time in the calorific value of generated gas when the blower is operated under frequency control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are denoted by the same reference numerals, and duplicated description will be omitted.

[0013] Fig. 1 is an explanatory diagram showing a schematic configuration of a gasification apparatus according to this embodiment. The gasification apparatus 1 is an updraft type apparatus that gasifies wood chips S used as a biomass raw material by causing pyrolysis, oxidation, and reduction reactions in the wood chips S, and collects the generated product gas (e.g., carbon monoxide, hydrogen, etc.) from above. The pyrolysis, oxidation, and reduction reactions in this specification are reactions represented by the following reaction formulas.

[0014] [ka]

[0015] From the viewpoint of increasing the production efficiency of the generated gas obtained by the gasification process, it is preferable that the wood chips S are semi-carbonized in advance. The semi-carbonization of the wood chips S is a process in which the wood chips S are heated, for example, at 200 to 350°C in an atmosphere in which water vapor is supplied to a container with the oxygen supply limited or blocked, to adjust the moisture content of the wood chips S. The moisture content of the semi-carbonized wood chips S is, for example, 4 to 12% by mass, preferably 6 to 10% by mass, and more preferably 7 to 9% by mass.

[0016] The configuration of the gasification apparatus 1 will be outlined below, but the description of the apparatus configuration may be omitted for portions to which a known updraft type apparatus configuration can be applied.

[0017] The gasification apparatus 1 includes a reaction vessel 2 in which gasification processing of wood chips S is carried out, and a tapered vessel 3 provided inside the reaction vessel 2 as a raw material storage vessel.

[0018] The reaction vessel 2 is a vertical vessel having a substantially cylindrical shape. In the reaction vessel 2, three layers, a pyrolysis zone T1, a combustion zone T2, and a reduction zone T3, are formed in this order from bottom to top when the wood chips S are gasified.

[0019] The pyrolysis zone T1 is a layer where a pyrolysis reaction of the wood chips S occurs by receiving heat from the combustion zone T2. The combustion zone T2 is a layer where an oxidation reaction occurs in the wood chips S and provides heat to the pyrolysis zone T1 and the reduction zone T3. The reduction zone T3 is a layer where a reduction reaction of the gas generated from the wood chips S occurs by receiving heat from the combustion zone T2, producing product gases such as carbon monoxide and hydrogen gas.

[0020] The temperature of the pyrolysis zone T1 during the gasification treatment is, for example, 300 to 500° C., the temperature of the combustion zone T2 is, for example, 500 to 650° C., and the temperature of the reduction zone T3 is, for example, 650° C. or higher. From the viewpoint of increasing the production efficiency of the generated gas generated in the reduction zone T3, the temperature of the reduction zone T3 during the gasification treatment is preferably 850° C. or lower.

[0021] The tapered container 3 is a container having a tapered portion 3a in the shape of a truncated cone, and the upper and lower ends of the tapered container 3 are open. The tapered portion 3a of the tapered container 3 is formed so as to expand in diameter from the lower end to the upper end of the tapered portion 3a. In other words, the tapered portion 3a is formed so that the cross-sectional area (area when cut horizontally) increases from the lower end to the upper end of the tapered portion 3a.

[0022] An annular flat portion 3b is formed at the upper end of the tapered portion 3a. An upwardly extending cylindrical wall portion 3c is formed on the periphery of the annular flat portion 3b. The lower end of the tapered portion 3a protrudes downward from the bottom surface 2c of the reaction vessel 2 and is connected to the upper end of a raw material supply passage 13, which will be described later. As a result, wood chips S supplied from the raw material supply passage 13 are supplied from the lower end of the tapered portion 3a, and the inside of the tapered vessel 3 is filled with wood chips S.

[0023] The shape of the tapered portion 3a is not limited to a truncated cone shape, but may be a truncated pyramid shape such as a truncated quadrangular pyramid shape.

[0024] At the upper end of the tapered portion 3a, an opening 4 is formed penetrating from the outer peripheral surface to the inner peripheral surface, and a plurality of openings 4 are provided at intervals in the circumferential direction of the tapered portion 3a. Each opening 4 may be a through hole having a shape that prevents the wood chips S stored in the tapered container 3 from falling out of the opening 4, and may be, for example, a slit, a round hole, a square hole, or the like.

[0025] The above-mentioned opening 4 is located at the height of an area corresponding to the combustion zone T2 formed during the gasification process of the wood chips S, and a combustion-promoting gas described below that promotes the combustion of the wood chips S is supplied to the wood chips S in the combustion zone T2 through the opening 4.

[0026] The size of the region of each of the above-mentioned pyrolysis zone T1, combustion zone T2, and reduction zone T3 varies depending on the configuration of the apparatus, such as the shape of the reaction vessel 2 and the shape of the tapered vessel 3, but a person skilled in the art can estimate the size of the region of each of the layers from the configuration of the gasification apparatus. In other words, a person skilled in the art can determine whether or not, in a gasification apparatus having a tapered vessel with an opening, the opening is formed at the height of the region corresponding to the combustion zone T2.

[0027] The shape, material, size, etc. of the reaction vessel 2 described above and the tapered vessel 3 described below are not particularly limited as long as they are capable of carrying out gasification processing of the wood chips S. For example, the shape of the reaction vessel 2 is not limited to a cylindrical shape, and may be a rectangular tube shape. The size of the reaction vessel 2 is, for example, a total length (vertical length) of 1200 to 1800 mm and a diameter of 500 to 1800 mm.

[0028] The material of the tapered vessel 3 may be, for example, stainless steel, carbon steel, silicon carbide (SiC), brick, etc., but it is preferable to use stainless steel from the viewpoint of ease of shaping and heat resistance. In addition, the tapered vessel 3 may be coated, for example, by calorizing treatment on the inner surface.

[0029] 1, a heat insulating material 5 is provided on the inner surface of the reaction vessel 2. The heat insulating material 5 is provided as necessary depending on the shapes of the reaction vessel 2 and the tapered vessel 3. In this embodiment, the heat insulating material 5 is provided on the entirety of the ceiling surface 2a and the side surface 2b in the reaction vessel 2 and on a partial area of ​​the bottom surface 2c.

[0030] At the lower part of the heat insulating material 5, an inclined portion 5a is formed in a portion facing the tapered portion 3a of the tapered vessel 3, and the inclined portion 5a of the heat insulating material 5 and the tapered portion 3a of the tapered vessel 3 are in a substantially parallel state. The inclined portion 5a and the tapered portion 3a are not in contact with each other, but are spaced apart. At the upper end of the inclined portion 5a of the heat insulating material 5, a flat portion 5b is formed on which the annular flat portion 3b of the tapered vessel 3 rests. In addition, the inner surface of the heat insulating material 5 on the inside of the side wall of the reaction vessel 2 is in contact with the outer peripheral surface of the cylindrical wall portion 3c of the tapered vessel 3.

[0031] As shown in FIG. 1, a heater 6 is provided inside the reaction vessel 2. The heater 6 is a device that increases the internal temperature of the reaction vessel 2 and raises the temperature of the combustion zone T2 to a predetermined temperature (for example, 450 to 600°C) when starting the gasification process of the wood chips S. When performing the gasification process, the heater 6 is stopped after the combustion zone T2 reaches the predetermined temperature. The heat source of the gasification process after the heater 6 is stopped is the combustion heat generated by the oxidation reaction in the combustion zone T2, and this combustion heat 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 reaction and reduction reaction of the gas generated from the wood chips S automatically proceed.

[0032] The heater 6 is an example of a means for increasing the temperature of the combustion zone T2. Therefore, if the temperature of the combustion zone T2 can be increased by other means, such as a known temperature increasing means, the heater 6 does not need to be provided. For example, instead of the heater 6, an ignition device (not shown) for igniting the wood chips S in the combustion zone T2 may be provided.

[0033] (Temperature Sensor) A temperature sensor 7 for measuring the atmospheric temperature inside the reaction vessel 2 is provided on the upper part of the side wall of the reaction vessel 2. The temperature sensor 7 is, for example, a thermocouple type sensor, and the temperature measurement unit 7a is located inside the heat insulating material 5 arranged inside the reaction vessel 2 and above the upper end of the tapered vessel 3. In other words, the temperature measurement unit 7a is located above the wood chips S in the reduction zone T3.

[0034] During the gasification process of the wood chips S, the atmospheric temperature inside the reaction vessel 2 is measured by the temperature sensor 7, and information on the measured atmospheric temperature inside the reaction vessel 2 is output to the control unit 100 described later. Although not shown, the gasification apparatus 1 is also provided with various sensors such as a temperature sensor for measuring the temperatures of the pyrolysis zone T1 and the combustion zone T2, and a sensor for measuring the amount of wood chips S stored in the tapered vessel 3.

[0035] A discharge pipe 8 is provided at the upper part of the side wall of the reaction vessel 2. The discharge pipe 8 is a pipe for discharging to the outside the product gas (e.g., carbon monoxide, hydrogen, etc.) generated inside the reaction vessel 2. The product gas discharged from the discharge pipe 8 is sent to a product gas storage section (not shown) and is used, for example, as fuel for biomass power generation.

[0036] Next, we will explain the raw material supply mechanism 10 that supplies the wood chips S to the reaction vessel 2. The raw material supply mechanism 10 has an input section 11 where the wood chips S are input, a transport path 12 that transports the wood chips S input 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.

[0037] 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 has a shape extending in the height direction of the reaction vessel 2, and the wood chips S input into the hopper 14 are stored inside the input passage 15.

[0038] The transport path 12 has a shape extending horizontally, and the lower end of the above-mentioned input path 15 is connected to the outer circumferential surface of the transport path 12, and the tip end of the transport path 12 is connected to the raw material supply path 13.

[0039] The raw material supply path 13 has a shape extending in the height direction of the reaction vessel 2, and a supply port (not shown) is formed on the upper surface of the raw material supply path 13 for supplying wood chips S toward the reaction vessel 2. Screws 16, 17 are provided inside the transport path 12 and the raw material supply path 13, respectively, and are rotated by a rotary drive source (not shown) such as a motor.

[0040] According to the raw material supply mechanism 10 having the above-mentioned configuration, wood chips S fed into the feed 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. As a result, a piled layer of wood chips S is formed inside the tapered vessel 3 serving as a raw material storage vessel, and gasification processing is performed. During gasification processing, the screws 16, 17 rotate at a constant cycle, and a constant amount of wood chips S continues to be supplied to the tapered vessel 3 per unit time.

[0041] (Gas supply mechanism) Next, a description will be given of the gas supply mechanism 20 that supplies a combustion promoting gas to the combustion zone T2. The combustion promoting gas is a gas (eg, air) for promoting the combustion of the wood chips S in the combustion zone T2.

[0042] The gas supply mechanism 20 includes a blower 21 as an air blower that supplies a combustion promoting gas into the reaction vessel 2, a pipe 22 through which the combustion promoting gas sent from the blower 21 flows, and a gas supply pipe 23 branched off from the pipe 22.

[0043] The gas supply pipes 23 are connected to the bottom of the reaction vessel 2, and are provided at intervals along the circumferential direction of the reaction vessel 2. The combustion promotion gas supplied from these gas supply pipes 23 is supplied to the inside of the reaction vessel 2 and to the outside of the tapered vessel 3. In this embodiment, a gap is formed between the inclined portion 5a of the heat insulating material 5 and the tapered portion 3a of the tapered vessel 3, and this gap serves as a gas flow path 24 for the combustion promotion gas.

[0044] The gas flow passage 24 extends from the connection position between the reaction vessel 2 and the gas supply pipe 23 to the formation position of the opening 4. This gas flow passage 24 is an annular space formed along the outer circumferential surface of the tapered portion 3a, and the combustion promotion gas supplied from the gas supply pipe 23 flows within this space. The combustion promotion gas is then supplied from the space through the opening 4 from the outside to the inside of the tapered vessel 3. As described above, the opening 4 is formed in the region corresponding to the combustion zone T2 of the tapered vessel 3, and therefore the combustion promotion gas passing through the opening 4 is supplied to the wood chips S stored in the combustion zone T2.

[0045] The gas supply pipe 23 may be connected to, for example, the side wall of the reaction vessel 2. Even in this case, if the combustion promotion gas can be supplied from the gas supply pipe 23 to the gas flow passage 24, the combustion promotion gas can be supplied to the combustion zone T2 through the opening 4.

[0046] The operation of the gas supply mechanism 20 having the above configuration is controlled, for example, by the control unit 100 described later. Specifically, for example, the blower 21 of the gas supply mechanism 20 switches between an ON state and an OFF state based on the ambient temperature in the reaction vessel 2 measured by the temperature sensor 7, thereby adjusting the flow rate of the combustion promotion gas supplied into the reaction vessel 2.

[0047] From the viewpoint of adjusting the flow rate of the combustion promotion gas while suppressing abrupt fluctuations in the atmospheric temperature inside the reaction vessel 2, it is preferable to provide an inverter 25 capable of variably controlling the frequency, and to be able to change the set frequency of the inverter 25 based on the atmospheric temperature inside the reaction vessel 2. According to the gas supply mechanism 20 having such a configuration, the air volume of the blower 21 can be smoothly changed according to the set frequency of the inverter 25, so that abrupt fluctuations in the atmospheric temperature inside the reaction vessel 2 can be suppressed, as shown in the examples described later. The inverter 25 may be built into the blower 21 or may be installed outside the blower 21.

[0048] (Control unit) The gasification apparatus 1 includes a control unit 100 that controls the operations of the raw material supply mechanism 10, the gas supply mechanism 20, and the like. The control unit 100 is, for example, a computer equipped with a CPU, a memory, and the like, and has a program storage unit (not shown). The program storage unit stores various programs that control the gasification process based on information obtained from various sensors installed in the gasification apparatus 1. The above programs may be recorded in a computer-readable storage medium and installed in the control unit 100 from the storage medium.

[0049] The control unit 100 adjusts the flow rate of the combustion promoting gas so that the atmospheric temperature in the reaction vessel 2 measured by the temperature measuring unit 7a of the temperature sensor 7 falls within a target temperature range (for example, 650 to 850°C). The "target temperature range" is appropriately set by a person skilled in the art depending on the configuration of the gasification apparatus 1.

[0050] For example, when the temperature measured by the temperature measuring unit 7a is lower than the lower limit of the target temperature range, the blower 21 is turned on based on a control signal output from the control unit 100, and the supply of combustion promotion gas to the combustion zone T2 is started. This facilitates the progress of the oxidation reaction of the wood chips S in the combustion zone T2, and the temperature of the combustion zone T2 increases. As a result, the temperature of the wood chips S in the reduction zone T3 increases due to the heat transferred from the combustion zone T2, and the atmospheric temperature in the reaction vessel 2 also increases.

[0051] On the other hand, for example, when the temperature measured by the temperature measuring unit 7a is higher than the upper limit of the target temperature range, the blower 21 is turned off based on a control signal output from the control unit 100, and the supply of the combustion promotion gas to the combustion zone T2 is stopped. This slows down the oxidation reaction of the wood chips S in the combustion zone T2, and the temperature rise in the combustion zone T2 is suppressed. As a result, the temperature rise of the wood chips S in the reduction zone T3 is suppressed, and the atmospheric temperature in the reaction vessel 2 gradually decreases.

[0052] Furthermore, when an inverter 25 is provided as shown in FIG. 1, the control unit 100 performs control to change the set frequency of the inverter 25 so that the ambient temperature inside the reaction vessel 2 measured by, for example, the temperature measuring unit 7a becomes a temperature within a target temperature range.

[0053] For example, when the temperature measured by the temperature measuring unit 7a is lower than the lower limit of the target temperature range, the control unit 100 controls the set frequency of the inverter 25 to be increased continuously or stepwise so that the measured temperature falls within the target temperature range. As a result, the input frequency to the blower 21 also increases continuously or stepwise, and the air volume of the blower 21 and the flow rate of the combustion promoting gas supplied to the combustion zone T2 increase continuously or stepwise.

[0054] On the other hand, for example, when the temperature measured by the temperature measuring unit 7a is higher than the upper limit of the target temperature range, the control unit 100 performs control to continuously or stepwise lower the set frequency of the inverter 25 so that the measured temperature falls within the target temperature range. As a result, the input frequency to the blower 21 also decreases continuously or stepwise, and the air volume of the blower 21 and the flow rate of the combustion promoting gas supplied to the combustion zone T2 decrease continuously or stepwise.

[0055] Furthermore, for example, when the temperature measured by the temperature measuring unit 7a is within a target temperature range, the control unit 100 performs control to maintain the set frequency of the inverter 25 without changing it in order to maintain the state in which the measured temperature is within the target temperature range. This makes it difficult for the temperatures in the pyrolysis zone T1, combustion zone T2, and reduction zone T3 to deviate from the appropriate temperatures during gasification treatment, and makes it possible to stabilize the amount of generated gas (e.g., carbon monoxide, hydrogen, etc.) generated.

[0056] The schematic configuration of the gasification apparatus 1 according to this embodiment has been described above. In this gasification apparatus 1, the temperature measurement unit 7a is provided above the upper end of the tapered vessel 3 in the reaction vessel 2, and the temperature measurement unit 7a measures the atmospheric temperature in the reaction vessel 2. Then, the flow rate of the combustion promotion gas is adjusted so that the atmospheric temperature in the reaction vessel 2 measured by the temperature measurement unit 7a falls within a target temperature range.

[0057] That is, according to the gasification apparatus 1 of this embodiment, the flow rate of the combustion promotion gas can be controlled based on the ambient temperature in the reaction vessel 2, which has a stable temperature transition compared to the combustion zone T2, which is prone to an unstable temperature transition during the gasification process. This improves the accuracy of the flow rate adjustment of the combustion promotion gas during the gasification process, and makes it easier to supply the combustion promotion gas at an appropriate flow rate for maintaining the pyrolysis zone T1, the combustion zone T2, and the reduction zone T3 in the reaction vessel 2 at appropriate temperatures.

[0058] In particular, in the gasification system 1 according to this embodiment, the air volume of the blower 21 can be changed by controlling the frequency of the blower 21 using the inverter 25. This allows the flow rate of the combustion promoting gas supplied to the combustion zone T2 to be changed smoothly, and as will be shown in the examples described later, it is possible to suppress abrupt fluctuations in the ambient temperature and the calorific value of the generated gas compared to the case where the blower 21 is controlled to be turned on and off.

[0059] Although the embodiment of the present invention has been exemplified above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0060] For example, the components of the above-described embodiments may be combined in any manner. Any combination will naturally provide the functions and advantages of each of the components in the combination, and will also provide other functions and advantages that will be apparent to those skilled in the art from the description of this specification. EXAMPLES

[0061] A combustion experiment of wood chips was carried out using a gasification apparatus. Figure 2 is an explanatory diagram showing the schematic configuration of a gasification apparatus 1A used in the combustion experiment. In the gasification apparatus 1A, thermocouple-type temperature sensors TR1 and TR2 are installed on the side wall of a reaction vessel 2.

[0062] The temperature sensor TR1 is disposed at a height equivalent to the top of the tapered vessel 3, and the temperature measurement portion of the temperature sensor TR1 is located inside the piled layer of wood chips S in the combustion zone T2. The temperature sensor TR1 measures the temperature of the combustion zone T2.

[0063] The temperature sensor TR2 is disposed above the upper end of the tapered vessel 3, and the temperature measurement portion of the temperature sensor TR2 is located above the piled layer of wood chips S in the reduction zone T3. The atmospheric temperature in the reaction vessel 2 is measured by this temperature sensor TR2.

[0064] Other configurations of the gasification apparatus 1A are similar to those of the gasification apparatus 1 shown in FIG.

[0065] (Combustion experiment 1) In a combustion experiment using the gasification apparatus 1, first, wood chips S were supplied from the raw material supply line 13 at a rate of 100 kg / h while a constant amount of air was supplied as a combustion promoting gas from the gas supply pipe 23 to carry out a gasification process of the wood chips. The temperatures measured by the temperature sensors TR1 and TR2 at this time were monitored.

[0066] Figure 3 is a graph showing the change over time in temperature measured by temperature sensors TR1 and TR2. As shown in Figure 3, the temperature measured by temperature sensor TR1, i.e., the temperature in combustion zone T2, was unstable, while the temperature measured by temperature sensor TR2, i.e., the atmospheric temperature in reaction vessel 2, was stable. In addition, considering that the atmospheric temperature in reaction vessel 2 was constant at about 800°C, it can be determined that the temperature of reduction zone T3 was appropriate, and therefore it can be estimated that the temperatures of combustion zone T2 and pyrolysis zone T1 are also appropriate.

[0067] Therefore, by adjusting the flow rate of the combustion promotion gas based on the atmospheric temperature inside the reaction vessel 2, it is possible to adjust the flow rate more appropriately than when the flow rate is adjusted based on the temperature of the combustion zone T2.

[0068] (Combustion experiment 2) Next, a combustion experiment was carried out in which air was supplied as a combustion promoting gas from the gas supply pipe 23 and the flow rate of the air was controlled based on the temperature measured by the temperature sensor TR2, i.e., the atmospheric temperature inside the reaction vessel 2. Specifically, a combustion experiment was carried out in which the air flow rate was adjusted by ON / OFF control of the blower 21 without using the inverter 25 shown in FIG. 2, and a combustion experiment was carried out in which the air flow rate was adjusted by frequency control of the blower 21 using the inverter 25. In both combustion experiments, the operation of the blower 21 was controlled so that the temperature measured by the temperature sensor TR2 was within the range of 730 to 820°C.

[0069] FIG. 4 is a graph showing the change over time in the temperature measured by temperature sensor TR2 and the input frequency to the blower when the blower is operated with ON / OFF control. FIG. 5 is a graph showing the change over time in the calorific value of the generated gas when the blower is operated with ON / OFF control. The "calorific value of generated gas" in FIG. 5 is the gas concentration (%) of carbon monoxide gas, methane gas, and hydrogen gas in the generated gas measured by a gas analyzer (not shown), and the unit calorific value (MJ / m) specific to each gas. 3 ) is the sum of the values ​​calculated by multiplying each of them.

[0070] As shown in Fig. 4, when the air flow rate was adjusted by controlling the blower ON / OFF, the temperature measured by the temperature sensor TR2 was likely to overshoot the target temperature range (725 to 825°C), resulting in large fluctuations in the ambient temperature inside the reaction vessel 2. In addition, as shown in Fig. 5, the calorific value of the generated gas also fluctuated greatly, resulting in an unstable calorific value.

[0071] On the other hand, Fig. 6 is a graph showing the change over time in the temperature measured by the temperature sensor TR2 and the input frequency to the blower when the blower is operated under frequency control. Fig. 7 is a graph showing the change over time in the calorific value of the generated gas when the blower is operated under frequency control. The calculation method for the "calorific value of the generated gas" in Fig. 7 is the same as in Fig. 5.

[0072] As shown in Figure 6, when the air flow rate was adjusted by controlling the blower frequency, the temperature measured by the temperature sensor TR2 was less likely to overshoot the target temperature range (725 to 825°C), and sudden fluctuations in the ambient temperature were suppressed. In addition, as shown in Figure 7, sudden fluctuations in the calorific value of the generated gas were also suppressed. In other words, by operating the blower by frequency control, it is possible to suppress sudden fluctuations in the ambient temperature in the reaction vessel and the calorific value of the generated gas more effectively than with ON / OFF control.

[0073] Therefore, from the viewpoint of easily maintaining the temperature state in the reaction vessel at an appropriate temperature state while suppressing abrupt fluctuations in the ambient temperature in the reaction vessel and the heat generation amount of the generated gas, it is preferable to adjust the flow rate of the combustion promotion gas supplied to the combustion zone T2 by controlling the frequency of the blower.

[0074] The above describes the embodiments of the present invention. The effects described in this specification are merely explanatory or exemplary, and are not limiting. In other words, the technology disclosed herein may provide other effects that are apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above effects. [Industrial Applicability]

[0075] The present invention can be applied to the gasification treatment of wood chips. [Explanation of symbols]

[0076] 1 Gasifier 1A Gasifier 2 Reaction vessel 2a Ceiling surface 2b side 2c Bottom 3 Tapered container 3a Tapered section 3b Annular plane part 3c Cylindrical wall part 4 Openings 5. Insulation 5a Slope 5b Plane part 6 Heater 7 Temperature Sensor 7a Temperature measurement part 8 discharge tube 10 Raw material supply mechanism 11 Input section 12 Transport path 13 Raw material supply route 14 Hopper 15 Input route 16 Screw 17 Screw 20 Gas supply mechanism 21 Blois 22 Piping 23 Gas supply pipe 24 Gas flow path 25 Inverter 100 Control section S Wood chips T1 Pyrolysis Zone T2 Combustion Zone T3 Reduction Zone TR1 Temperature Sensor TR2 Temperature Sensor

Claims

1. A gasification apparatus for gasifying wood chips, A reaction vessel in which the wood chips are gasified; A raw material supply channel disposed at the bottom of the reaction vessel; a raw material storage container provided inside the reaction container and receiving the wood chips from the raw material supply passage; A gas supply mechanism that supplies a combustion promoting gas that promotes combustion of the wood chips into the raw material storage container; a temperature measuring unit provided above an upper end of the raw material storage container and measuring an atmospheric temperature in the reaction container; A control unit that controls the operation of the gas supply mechanism, The control unit is A gasification apparatus, characterized in that a control is performed to adjust the flow rate of the combustion promotion gas so that the atmospheric temperature measured by the temperature measuring unit is within a target temperature range.

2. The gas supply mechanism includes: An inverter capable of variable frequency control; a blower that blows the combustion promotion gas at an air volume corresponding to a set frequency of the inverter, The control unit is 2. The gasification apparatus according to claim 1, wherein a control is performed to adjust a set frequency of the inverter so that the atmospheric temperature measured by the temperature measuring unit falls within a target temperature range.

3. A gasification treatment method using a gasification apparatus for gasifying wood chips, comprising: The gasification apparatus comprises: A reaction vessel in which the wood chips are gasified; A raw material supply channel disposed at the bottom of the reaction vessel; a raw material storage container provided inside the reaction container and receiving the wood chips from the raw material supply passage; During the gasification process, A combustion promoting gas for promoting combustion of the wood chips is supplied into the raw material storage container; A gasification processing method, characterized in that the atmospheric temperature in the reaction vessel is measured above the upper end of the raw material storage vessel, and the flow rate of the combustion promotion gas is adjusted so that the measured atmospheric temperature is within a target temperature range.

4. The gasification apparatus comprises: An inverter capable of variable frequency control; a blower that blows the combustion promotion gas at an air volume corresponding to a set frequency of the inverter, 4. The gasification method according to claim 3, wherein, when performing the gasification treatment, a set frequency of the inverter is adjusted so that the measured atmospheric temperature falls within a target temperature range.

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