Combustion device, combustion method, and memory medium

Abstract

A circulating fluidized bed (CFB) boiler is a combustion device in which fuel charged into a furnace 11 is combusted, the CFB boiler comprising: a fuel supply part 14 that is provided with a fuel supply port 14I to which fuel is supplied and a fuel charging port 14O through which the fuel is charged into the furnace 11; state-quantity acquisition parts 81, 82, 83 that acquire a state quantity representing the internal state of the fuel supply part 14 between the fuel supply port 14I and the fuel charging port 14O; and an automatic gate valve 7A that opens and closes the fuel supply port 14I in accordance with the state quantity. The fuel supply part 14A includes thereinside a fluid circulation part 9 for flowing fluid toward the fuel charging port 14O. The state quantity represents the pressure and / or flow rate of the fluid.

Description

Combustion device, combustion method, and storage medium

[0001] The present disclosure relates to combustion devices and the like.

[0002] Known boilers (combustion devices) that generate steam from water using heat generated by the combustion of fuel include bubbling fluidized bed (BFB) boilers and circulating fluidized bed (CFB) boilers, which burn fuel using a fluidized bed formed by a fluidizing material such as silica sand flowing in a combustion chamber. Patent Document 1 discloses a CFB boiler.

[0003] Japanese Patent Application Laid-Open No. 2012-255612

[0004] Conventional combustion devices often use fossil fuels such as coal as fuel. However, due to growing environmental awareness in recent years, the use of biomass fuels, which have a smaller environmental impact than fossil fuels, has also increased. Wood pellets derived from wood are a typical example of biomass fuel. Wood pellets tend to expand when they absorb moisture, so they are preferably used in a dry state. However, dry wood pellets can generate a large amount of powder when placed in the combustion chamber, so safety measures are required to prevent the powder from igniting due to heat inside the combustion chamber.

[0005] The present disclosure has been made in view of the above circumstances, and aims to provide a combustion device and the like that can effectively prevent excessive combustion of fuel in a fuel supply section.

[0006] In order to solve the above problems, a combustion device according to one aspect of the present disclosure is a combustion device that injects fuel into a combustion chamber and burns it, and includes a fuel supply unit that includes a fuel supply port through which fuel is supplied and a fuel inlet that injects the fuel into the combustion chamber, and an opening / closing unit that opens and closes the fuel supply port depending on a state quantity between the fuel supply port and the fuel inlet.

[0007] According to this aspect, the combustion of fuel in the fuel supply unit or signs thereof can be effectively detected based on the state quantity, and the expansion of the combustion can be prevented by closing the fuel supply port with the opening / closing unit.

[0008] Another aspect of the present disclosure is a combustion method for injecting fuel into a combustion chamber and burning the fuel, the method comprising: opening and closing a fuel supply port through which fuel is supplied and a fuel supply port that injects the fuel into the combustion chamber, in accordance with a state quantity between the fuel supply port and the fuel supply port.

[0009] Yet another aspect of the present disclosure is a storage medium that stores a combustion program for injecting fuel into a combustion chamber and burning the fuel, the combustion program causing a computer to open and close the fuel supply port in accordance with a state quantity between a fuel supply port through which fuel is supplied and a fuel inlet that injects the fuel into the combustion chamber.

[0010] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure.

[0011] According to the present disclosure, excessive combustion of fuel in the fuel supply unit can be effectively prevented.

[0012] Schematic diagram of a CFB boiler. Schematic diagram of the fuel supply section. Schematic diagram of the expected time-dependent changes in each state quantity when combustible powder derived from wood pellets ignites in the feeder due to heat in the furnace.

[0013] Hereinafter, with reference to the drawings, a detailed description will be given of a mode for carrying out the present disclosure (hereinafter also referred to as an embodiment). In the description and / or drawings, identical or equivalent components, members, processes, etc. are designated by the same reference numerals, and redundant description will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the description and should not be interpreted as limiting unless otherwise specified. The embodiment is an example and does not limit the scope of the present disclosure in any way. Not all features and their combinations presented in the embodiment are necessarily essential to the present disclosure. For convenience, the embodiment is presented broken down into components for each function and / or functional group that realizes the embodiment. However, one component in the embodiment may actually be realized by a combination of multiple separate components, or multiple components in the embodiment may actually be realized by a single integrated component.

[0014] 1 is a schematic diagram of a circulating fluidized bed (CFB) boiler serving as a combustion apparatus according to the present embodiment. Note that any other combustion apparatus, such as a bubbling fluidized bed (BFB) boiler or a rotary kiln, may be used instead of the CFB boiler. Furthermore, any other type of boiler, such as a reheat boiler or a once-through boiler, may also be used as the combustion apparatus according to the present disclosure.

[0015] The CFB boiler is equipped with a combustion section 1 in which fuel such as biomass fuel or fossil fuel such as coal is supplied and burned in a furnace 11 in which fluidizing material such as silica sand flows, a steam generation section 2 that generates steam from water using heat generated in the combustion section 1, a fluidizing material circulation section 3 that serves as a circulation section that collects the fluidizing material that has left the furnace 11 and returns it to the furnace 11, a heat transfer section 4 that heats the water supplied to the steam generation section 2 and the steam generated in the steam generation section 2 using the high-temperature exhaust gas from the combustion section 1, an exhaust gas treatment device 5 that separates and collects soot and dust in the exhaust gas from the heat transfer section 4, and a chimney 6 that releases the exhaust gas purified by the exhaust gas treatment device 5 into the atmosphere.

[0016] The combustion section 1 includes a furnace 11 as a combustion chamber. The furnace 11 is a vertically elongated cylindrical shape with a tapered bottom to increase the density of solid fuels such as biomass fuel and coal, and fluidized material, enabling efficient combustion. The bottom of the furnace 11 does not have to be tapered, and the furnace 11 may be formed as a cylinder with a substantially constant cross-sectional shape from top to bottom. The region marked "A" at the bottom of the furnace 11 indicates a fluidized bed (also called a fluidized bed or sand layer) formed by a high-density fluidized material. In the fluidized bed A, powdery, granular, or lumpy fluidized material such as silica sand is fluidized by a fluid supplied from the bottom of the furnace 11. The solid fuels such as biomass fuel and coal introduced into the fluidized bed A are repeatedly agitated within the fluidized bed A and are thereby efficiently combusted.

[0017] Since the fluidized material rises within the furnace 11 due to the updrafts generated by combustion, the fluidized material also exists in the freeboard B, which is the space above the fluidized bed A. The density of the fluidized material in the freeboard B is lower than that in the fluidized bed A, and decreases the higher in the furnace 11. In the freeboard B, fuel that was not completely combusted in the fluidized bed A is combusted while coming into contact with the floating fluidized material. Although silica sand is exemplified as the fluidized material, any material may be used as long as it remains in a solid state without being combusted even in the high-temperature furnace 11 and functions as a medium for transferring heat to the fuel while fluidizing, and for example, other types of sand, stone such as limestone, or ash may also be used.

[0018] A perforated plate (also called a dispersion plate) 121 serving as a fluid-permeable portion and made of a porous material that allows a fluid such as air to pass through is provided at the bottom of the furnace 11. A wind box 122, which is the space directly below the perforated plate 121, constitutes a fluid supply portion that supplies compressed air or other fluid as a fluid supplied from the first ventilator 71 serving as an air blower via the first flow control valve 71A into the furnace 11 via the perforated plate 121. The fluid supplied to the bottom of the furnace 11 by the wind box 122 fluidizes the fluid material to form a fluidized bed A and is also used for combustion of fuel in the fluidized bed A or the freeboard B. While the perforated plate 121 is illustrated in FIG. 1 as an example of a fluid-permeable portion, any fluid-permeable portion may be used as long as it can fluidize the fluid material in the fluidized bed A. For example, the fluid-permeable portion may be formed from a number of plates each having slits formed therein for supplying the fluid into the furnace 11.

[0019] The second fan 72, which is provided in addition to the first fan 71, supplies compressed air or the like into the freeboard B via a second flow control valve 72A in order to promote the combustion of fuel in the freeboard B and to suppress the generation of harmful substances such as dioxins and carbon monoxide due to incomplete combustion.

[0020] The bottom side of the furnace 11 may be provided with an extraction pipe 131 that is connected to the bottom and can extract a portion of the fluidized material in the fluidized bed A, and an on-off valve 132 that can control the opening and closing of the extraction pipe 131 to adjust the flow rate of the fluidized material, i.e., the amount of fluidized material extracted by the extraction pipe 131.

[0021] The furnace wall, which is the side wall of the furnace 11, is provided with a fuel supply unit 14 that supplies fuel into the furnace 11, a fluidizing material supply unit 15 that supplies a fluidizing material for forming a fluidized bed A into the furnace 11, and a startup unit 16 that starts the CFB boiler. As will be described in detail later, the fuel supply unit 14 includes a fuel storage unit 141 that stores fuel, a crushing unit 142 that crushes the fuel discharged from the bottom of the fuel storage unit 141 into granules, and a feeder 143 that feeds the fuel crushed by the crushing unit 142 into the furnace 11. The bottom of the fuel storage unit 141 may have any shape, for example, a flat bottom or a funnel shape. Hereinafter, the fuel supply unit 14 will be described as supplying solid fuel, but it may also supply a fluid fuel, such as liquid or gaseous biomass fuel, oil, ammonia, or hydrogen, in addition to or instead of the solid fuel.

[0022] The fuel supply unit 14 supplies any fuel, such as fossil fuels such as coal, biomass fuels, sludge, waste materials, etc., into the furnace 11. In particular, biomass fuels are carbon-neutral fuels with low or no net carbon dioxide emissions (however, since they contain carbon, carbon dioxide is generated during combustion). In order to reduce the amount of carbon dioxide generated in the furnace 11, the fuel supply unit 14 may supply a carbon-free fuel, which does not contain carbon, into the furnace 11 in addition to a carbon-containing fuel such as biomass fuel.

[0023] The pulverizing section 142 in the fuel supply unit 14 pulverizes the solid fuel into particles before it is fed into the furnace 11. The size of solid fuel suitable for transportation to the CFB boiler or the fuel storage unit 141 may differ from the size of solid fuel suitable for combustion in the furnace 11, so the pulverizing section 142 pulverizes the solid fuel into particles with a particle size suitable for the latter. If the particle size suitable for each solid fuel differs, a pulverizing section 142 may be provided for each solid fuel, or the particle size when pulverizing each solid fuel in sequence using one pulverizing section 142 may be changed for each solid fuel. If there is no problem in feeding the solid fuel of the particle size stored in the fuel storage unit 141 directly into the furnace 11, the pulverizing section 142 may not be provided.

[0024] Here, terms such as "particle," "granular," and "particle size" do not specify a specific size or dimension. The size or dimension of the solid fuel supplied into the furnace 11 is arbitrary as long as it can achieve the desired combustion. For example, terms such as "lump," "lump-like," and "lump diameter" used for relatively large particles, and terms such as "powder," "powder-like," and "powder diameter" used for relatively small particles, are included in the terms "particle," "granular," and "particle size" in this embodiment. A required amount of the granular solid fuel pulverized by the pulverizing unit 142 is fed into the furnace 11 through the feeder 143. The amount of solid fuel fed into the furnace 11 may be controlled by the rotation speed of a conveyor or rotary feeder (not shown) provided between the fuel storage unit 141 and a rotary valve 144 (described later), or by the rotation speed of the feeder 143 (e.g., a screw conveyor).

[0025] The fluid material supply unit 15, which supplies the fluid material for forming the fluidized bed A, includes a funnel-shaped fluid material hopper 151 for storing the fluid material, and a fluid material feeder 152 for feeding the fluid material discharged from the bottom of the fluid material hopper 151 into the furnace 11. By controlling the rotation speed of the fluid material feeder 152, the required amount of fluid material is fed into the furnace 11.

[0026] The startup unit 16, which starts up the CFB boiler, includes a startup fuel storage unit 161, a startup fuel control valve 162, and a startup burner 163. The startup fuel storage unit 161 stores, for example, heavy oil. The startup fuel control valve 162 controls the amount of heavy oil supplied from the startup fuel storage unit 161 to the startup burner 163. Specifically, the startup fuel control valve 162 opens when the CFB boiler is started up, and supplies the heavy oil stored in the startup fuel storage unit 161 to the startup burner 163. The startup burner 163 heats the fluidized material in the fluidized bed A with a flame generated by the combustion of the heavy oil supplied from the startup fuel control valve 162. Because the startup burner 163 is installed at an angle downward, the surface of the fluidized bed A formed by the fluidized material is directly heated, thereby efficiently raising the temperature of the fluidized bed A and the inside of the furnace 11. Such a startup burner 163 is also called an above-sand burner because it heats the sandy fluidized bed A from above.

[0027] After the CFB boiler is started up with the fluidized bed A and the furnace 11 sufficiently heated, specifically, after the fluidized bed A is able to burn the fuel supplied from the fuel supply unit 14, the startup fuel control valve 162 switches to a closed state to stop the supply of heavy oil to the startup burner 163. In the subsequent normal operating state, the fuel supplied from the fuel supply unit 14 is burned in the high-temperature furnace 11.

[0028] The combustion section 1 of the CFB boiler has been described in detail above. Next, the components of the CFB boiler other than the combustion section 1 will be described. The steam generation section 2 includes a drum 21 that stores water for generating steam, a water supply pipe 22 that supplies water to the drum 21, a water pipe 23 that guides the water in the drum 21 into the high-temperature furnace 11 for heating, and a steam pipe 24 that discharges steam generated from the water heated by the water pipe 23 from the drum 21 as the output of the CFB boiler. The steam output from the steam pipe 24 rotates the steam turbine of the generator 25, generating electricity. The water supply pipe 22 forms an economizer that preheats the feedwater by meandering through the heat transfer section 4 through which high-temperature exhaust gas from the combustion section 1 passes, and the steam pipe 24 forms a superheater that superheats the steam by meandering through the heat transfer section 4 through which high-temperature exhaust gas from the combustion section 1 passes. Similarly, the pressurized air etc. supplied into the furnace 11 by the first fan 71 and the second fan 72 is also preheated by the high-temperature exhaust air in the heat transfer section 4 .

[0029] The fluidized material circulation section 3 includes a cyclone 31 that separates and collects granular fluidized material from the exhaust gas discharged from the top of the furnace 11, and a circulation seal 32 (also called a wall seal or seal pot) that returns the fluidized material collected by the cyclone 31 into the furnace 11. The cyclone 31 is a cyclone-type powder separator with an approximately cylindrical upper portion and an approximately conical lower portion, and generates an airflow that descends in a spiral shape along the inner wall. The granular fluidized material contained in the exhaust gas from the furnace 11 falls into contact with the inner wall of the cyclone 31 as it descends in a spiral shape along the airflow, and is collected.

[0030] A circulation seal 32 provided below the cyclone 31 is filled with fluidizing material (not shown) and prevents unburned gas and the like from flowing back from the furnace 11 to the cyclone 31. The granular fluidizing material filled in the circulation seal 32 is gradually returned to the furnace 11 by being pushed out by the weight of the fluidizing material newly collected by the cyclone 31. Note that the fluidizing material passing through the circulation seal 32 may be mixed with combustion ash of biomass fuel and the like burned in the furnace 11.

[0031] FIG. 2 schematically illustrates details of the fuel supply unit 14 according to this embodiment. As described above, the fuel supply unit 14 includes a fuel storage unit 141 and a feeder 143 that feeds fuel into the furnace 11. In the example shown in this figure, the pulverizer 142 shown in FIG. 1 is omitted. The fuel supply unit 14 includes a fuel supply port 14I through which fuel stored in the fuel storage unit 141 is supplied and a fuel inlet 14O through which the fuel is fed into the furnace 11. The fuel stored in the fuel storage unit 141 is supplied to the fuel supply port 14I via a rotary valve 144. The amount or speed of fuel supplied to the fuel supply port 14I is appropriately adjusted by controlling a conveyor (not shown) or the rotational speed of the rotor in the rotary valve 144.

[0032] The fuel supply port 14I is provided with an automatic gate valve 7A and a manual gate valve 7M as opening / closing devices that can open and close the fuel supply port 14I. As will be described later, the automatic gate valve 7A can automatically open and close the fuel supply port 14I, and the manual gate valve 7M can manually open and close the fuel supply port 14I. Except for exceptional cases that will be described later, the automatic gate valve 7A and the manual gate valve 7M are open as a general rule while fuel is being introduced into the furnace 11 through the fuel inlet 14O, and the required amount of fuel is supplied continuously or intermittently through the open fuel supply port 14I.

[0033] The feeder 143 constitutes a solid fuel transport unit that transports solid fuel, such as biomass fuel, supplied from the fuel supply port 14I to the fuel inlet 14O. This feeder 143 is formed, for example, by a screw conveyor. The feeder 143 is preferably inclined downward toward the fuel inlet 14O so that the solid fuel supplied from the fuel supply port 14I and mechanically transported by the screw conveyor or the like is naturally guided to the fuel inlet 14O by its own weight. The rotation speed of the screw conveyor or the like may be constant or may be variable so that the amount of solid fuel introduced into the furnace 11 can be controlled.

[0034] As described above, the fuel supply unit 14 according to this embodiment can be used to supply various fuels into the furnace 11, but is particularly suitable for biomass fuel, which is attracting attention as a carbon-neutral fuel. For example, the fuel supply unit 14 according to this embodiment may be used to supply wood pellets, which are a typical example of solid biomass fuel, into the furnace 11.

[0035] Because wood pellets have the property of expanding when they absorb moisture, they are preferably supplied from the fuel supply port 14I in a dry state. Such dry wood pellets can generate a large amount of combustible or easily combustible powder (hereinafter also referred to as combustible powder) derived from wood when, for example, they drop from the fuel supply port 14I into the feeder 143, when they are mechanically transported by the feeder 143 such as a screw conveyor, or when they are fed into the furnace 11 through the fuel inlet 14O. Such combustible powder is easily ignited by the heat in the furnace 11 and is therefore effective in promoting combustion in the furnace 11. However, it is undesirable for the ignited combustible powder to flow back into the fuel supply unit 14.

[0036] In order to prevent such backflow of combustible powder, in this embodiment, a fluid circulation unit 9 is provided in the fuel supply unit 14, which allows a fluid to flow toward the fuel inlet 14O. The fluid may be, for example, any gas that does not interfere with the intended combustion of the fuel in the furnace 11, but in this embodiment, it is air. The fluid circulation unit 9 includes a fluid supply pipe 91 to which a fluid such as air is supplied, a first branch pipe 92 branching from the fluid supply pipe 91 and connecting to a portion subsequent to the fuel supply inlet 14I in the fuel supply unit 14, and a second branch pipe 93 branching from the fluid supply pipe 91 and connecting to a portion subsequent to the fuel supply inlet 14I in the fuel supply unit 14 (e.g., a rotary valve 144).

[0037] The first branch pipe 92 causes air to flow to the right in FIG. 2 immediately after the fuel supply port 14I and immediately before the feeder 143, for example. The second branch pipe 93 causes air to flow in the fuel supply direction (downward in FIG. 2) at the fuel supply port 14I through a rotary valve 144. The air from the first branch pipe 92 and the second branch pipe 93 merge immediately after the automatic gate valve 7A and the manual gate valve 7M provided at the fuel supply port 14I. Specifically, the downward air flow from the second branch pipe 93 merges with the rightward air flow from the first branch pipe 92, forming an air flow toward the feeder 143 and the fuel inlet 14O.

[0038] The fluid flow section 9 as described above allows air to steadily flow into the furnace 11 from the fuel inlet 14O, effectively preventing the combustible powder derived from wood pellets fed into the furnace 11 from the fuel inlet 14O from flowing back into the feeder 143.

[0039] In this embodiment, at least one state quantity acquisition unit is provided that acquires a state quantity that represents the state inside the fuel supply unit 14 between the fuel supply port 14I and the fuel input port 14O. In the example of Figure 2, three types of state quantity acquisition units are schematically shown.

[0040] The first state quantity acquisition unit is a temperature sensor 81 that measures the temperature inside the fuel supply unit 14. The temperature sensor 81 may, for example, measure the temperature inside the feeder 143, or may measure the temperature of the outer surface of the feeder 143 that is made of a material with high thermal conductivity, such as iron.

[0041] The second state quantity acquisition unit is a pressure sensor 82 that measures the pressure of a fluid such as air that the fluid circulation unit 9 flows into the fuel supply unit 14. The pressure sensor 82 may, for example, measure the pressure of air passing through any of the pipes 91 to 93 (preferably the first branch pipe 92 as shown in the figure) in the fluid circulation unit 9, or may measure the pressure of air in the fuel supply unit 14.

[0042] The third state quantity acquisition unit is a flow rate sensor 83 that measures the flow rate of a fluid, such as air, that the fluid circulation unit 9 flows into the fuel supply unit 14. The flow rate sensor 83 may, for example, measure the flow rate of air passing through any of the pipes 91 to 93 (preferably the fluid supply pipe 91 as shown in the figure) in the fluid circulation unit 9, or may measure the flow rate of air in the fuel supply unit 14.

[0043] The automatic gate valve 7A as an opening / closing unit opens and closes the fuel supply port 14I in accordance with at least one state quantity acquired by the various state quantity acquisition units as exemplified above. Specifically, the automatic gate valve 7A opens the fuel supply port 14I when each state quantity acquired by each state quantity acquisition unit is within a predetermined allowable range, and closes the fuel supply port 14I when the state quantity is outside the allowable range.

[0044] When the temperature inside the fuel supply unit 14 measured by the temperature sensor 81 is used as the state quantity, the automatic gate valve 7A opens the fuel supply port 14I when the temperature is equal to or lower than a predetermined upper limit temperature, and closes the fuel supply port 14I when the temperature exceeds the upper limit temperature. If the temperature inside the fuel supply unit 14 exceeds the upper limit temperature, the temperature may have risen sharply because combustible powder derived from wood pellets ignited by the heat inside the furnace 11 is flowing back into the feeder 143. Therefore, to prevent further spread of fire to the wood pellets in the fuel supply unit 14 or the fuel storage unit 141, the automatic gate valve 7A closes and forcibly shuts off the supply of fuel through the fuel supply port 14I.

[0045] When the air pressure measured by the pressure sensor 82 is used as the state quantity, the automatic gate valve 7A opens the fuel supply port 14I when the pressure is equal to or lower than a predetermined upper limit pressure, and closes the fuel supply port 14I when the pressure exceeds the upper limit pressure. If the pressure of the air flowing through the fluid circulation unit 9 into the fuel supply unit 14 exceeds the upper limit pressure, the pressure may have suddenly increased because combustible powder derived from wood pellets ignited by the heat in the furnace 11 is flowing back into the feeder 143. Therefore, to prevent further spread of fire to the wood pellets in the fuel supply unit 14 or the fuel storage unit 141, the automatic gate valve 7A closes and forcibly shuts off the supply of fuel through the fuel supply port 14I.

[0046] When the air flow rate measured by the flow rate sensor 83 is used as the state quantity, the automatic gate valve 7A opens the fuel supply port 14I when the flow rate is equal to or greater than a predetermined lower limit, and closes the fuel supply port 14I when the flow rate falls below the lower limit. If the flow rate of air flowing into the fuel supply unit 14 from the fluid circulation unit 9 falls below the lower limit, this may be because combustible powder derived from wood pellets ignited by heat in the furnace 11 is flowing back into the feeder 143, causing a sudden increase in air pressure in the fuel supply unit 14 (or a sudden expansion of the air), preventing the inflow of additional air from the fluid circulation unit 9, resulting in a sudden decrease in the flow rate. Therefore, to prevent further spread of fire to the wood pellets in the fuel supply unit 14 or the fuel storage unit 141, the automatic gate valve 7A closes, forcibly cutting off the supply of fuel through the fuel supply port 14I. The lower limit flow rate may be determined as the maximum decrease from the flow rate measured by the flow rate sensor 83 when the fuel supply unit 14 is operating normally.

[0047] 3 is a schematic diagram showing the expected changes over time in each state quantity when combustible powder derived from wood pellets ignites in the feeder 143 due to heat in the furnace 11. In this figure, the horizontal axis represents time, and the vertical axis represents each state quantity (therefore, the absolute values ​​on the vertical axis have no particular meaning).

[0048] As shown in the figure, the effect of the backflow of ignited combustible powder is thought to first become apparent in the form of a sudden increase in air pressure measured by pressure sensor 82 and / or a sudden decrease in air flow rate measured by flow sensor 83. Therefore, by using pressure sensor 82 and / or flow sensor 83, the risk of backflow of ignited combustible powder can be detected early and the automatic gate valve 7A can be quickly closed.

[0049] On the other hand, it is thought that the increase in temperature inside the fuel supply unit 14 measured by the temperature sensor 81 appears more slowly and with a time lag than the change in the air pressure and / or flow rate. However, since it is thought that the air pressure and / or flow rate may fluctuate greatly and become unstable, it is meaningful to use the temperature inside the fuel supply unit 14, which is a more stable indicator than these.

[0050] 2, in the fuel supply unit 14 according to this embodiment, in addition to or instead of the automatic opening and closing of the fuel supply port 14I by the automatic gate valve 7A, the non-flammable fluid supply unit 84 may supply a non-flammable fluid into the fuel supply unit 14. Specifically, when the state quantities acquired by the state quantity acquisition units 81 to 83 are outside the allowable ranges described above, the non-flammable fluid supply unit 84 supplies a non-flammable fluid, such as water vapor, nitrogen, or exhaust gas from the combustion unit 1, into the fuel supply unit 14. Even if combustible powder derived from wood pellets ignited by the heat in the furnace 11 flows back into the feeder 143, the non-flammable fluid quickly extinguishes or extinguishes the fire, preventing further spread of the fire to the wood pellets in the fuel supply unit 14 or the fuel storage unit 141.

[0051] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0052] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROM, RAM, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs.

[0053] The present disclosure relates to combustion devices and the like.

[0054] 1 Combustion section, 7A Automatic gate valve, 9 Fluid circulation section, 11 Furnace, 14 Fuel supply section, 14I Fuel supply port, 14O Fuel inlet, 81 Temperature sensor, 82 Pressure sensor, 83 Flow rate sensor, 84 Non-flammable fluid supply section, 141 Fuel storage section, 143 Feeder, 144 Rotary valve.

Claims

1. A combustion device that introduces fuel into a combustion chamber and burns it, comprising: a fuel supply unit having a fuel supply port through which the fuel is supplied and a fuel inlet for introducing the fuel into the combustion chamber; and an opening / closing unit that opens and closes the fuel supply port depending on a state quantity between the fuel supply port and the fuel inlet.

2. A combustion device according to claim 1, further comprising a state quantity acquisition unit that acquires the state quantity that represents a state within the fuel supply unit between the fuel supply port and the fuel inlet.

3. The combustion device according to claim 1, further comprising a fluid flow section that causes a fluid to flow toward the fuel inlet within the fuel supply section, and the state quantity is at least one of a pressure and a flow rate of the fluid.

4. The combustion device according to claim 3, wherein the fluid is a gas.

5. The combustion device according to claim 1, wherein the state quantity is a temperature in the fuel supply section.

6. A combustion device as described in any one of claims 1 to 5, wherein the opening / closing unit opens the fuel supply port when the state quantity is within a predetermined allowable range, and closes the fuel supply port when the state quantity is outside the allowable range.

7. A combustion apparatus according to any one of claims 1 to 5, further comprising a non-flammable fluid supply unit that supplies a non-flammable fluid into the fuel supply unit when the state quantity is outside a predetermined allowable range.

8. A combustion device according to any one of claims 1 to 5, wherein the fuel is a solid fuel.

9. The combustion device according to claim 8, wherein the solid fuel is a biomass fuel.

10. The combustion device according to claim 8, wherein the fuel supply section includes a solid fuel transport section that transports the solid fuel supplied from the fuel supply port to the fuel inlet.

11. A combustion method for injecting fuel into a combustion chamber and combusting it, comprising: opening and closing the fuel supply port according to a state quantity between a fuel supply port through which the fuel is supplied and a fuel inlet that injects the fuel into the combustion chamber.

12. A storage medium storing a combustion program for injecting fuel into a combustion chamber and burning the fuel, the combustion program causing a computer to execute the following: opening and closing the fuel supply port depending on a state quantity between a fuel supply port through which the fuel is supplied and a fuel inlet that injects the fuel into the combustion chamber.

Images