WO2022239654A1

WO2022239654A1 - Combustion device, boiler, combustion method

Info

Publication number: WO2022239654A1
Application number: PCT/JP2022/019015
Authority: WO
Inventors: 駿介中村; 祥章石井; 隆司大垣; 雄生山本; 竜徳柴田
Original assignee: 住友重機械工業株式会社
Priority date: 2021-05-11
Filing date: 2022-04-27
Publication date: 2022-11-17
Also published as: TW202309441A; JPWO2022239654A1

Abstract

A circulating fluidized bed boiler (a CFB boiler) that supplies fuel into a furnace 11 in which a fluid material is flowing to combust the fuel comprises carbon-free fuel supply units 16A–16D that supply ammonia or hydrogen into the furnace 11 as a carbon-free fuel that does not contain carbon. Carbon-free fuel supply unit 16A supplies the carbon-free fuel to a wind box 122, carbon-free fuel supply unit 16B supplies the carbon-free fuel to a fluidized bed A, carbon-free fuel supply unit 16C supplies the carbon-free fuel to the surface of the fluidized bed A, and carbon-free fuel supply unit D supplies the carbon-free fuel to a free board B.

Description

Combustion device, boiler, combustion method

The present invention relates to combustion equipment and boilers that burn fuel.

As a boiler that generates steam from water with the heat generated by combustion of fuel, a fluidized bed formed by a fluidized material such as silica sand flowing in the combustion chamber or a bubbling fluidized bed (BFB: Bubbling Fluidized Bed) boilers and Circulating Fluidized Bed (CFB) boilers are known. Patent Literature 1 discloses a CFB boiler.

JP 2012-255612 A

BFB boilers and CFB boilers can achieve high combustion efficiency by using a high-temperature fluid material that flows in the combustion chamber as a medium. It is suitable for burning fuels of unstable quality such as tires, etc., and flame-retardant fuels. However, since these fuels are mainly composed of carbon, they generate greenhouse gases such as carbon dioxide when burned, which may further exacerbate global warming. With the recent decarbonization movement, the demand for biomass fuel, which can be said to be carbon-neutral in the long term, is increasing, and it is becoming difficult to procure biomass fuel of stable quality at low cost and in a stable manner. Until now, in BFB boilers and CFB boilers mainly intended for burning flame-retardant carbon-containing fuels such as coal and waste fuels, in addition to utilizing biomass fuels, combustion methods that do not emit greenhouse gases such as carbon dioxide The challenge is to respond to

The present invention has been made in view of this situation, and its purpose is to provide a combustion apparatus and a boiler that can reduce the generation of greenhouse gases.

In order to solve the above-described problems, a combustion apparatus according to one aspect of the present invention is a combustion apparatus in which fuel is supplied to a combustion chamber in which a fluid material flows and is burned, wherein a carbon-free fuel that does not contain carbon is supplied to the combustion chamber. a carbon-free fuel supply that supplies the

Another aspect of the present invention is a boiler. This boiler has a combustion section that supplies fuel to the combustion chamber where the fluid material flows and burns, a carbon-free fuel supply section that supplies carbon-free carbon-free fuel into the combustion chamber, and a combustion section. and a steam generator for generating steam from water by heat.

It should be noted that any combination of the above constituent elements, and any conversion of the expression of the present invention between methods, devices, systems, recording media, computer programs, etc. are also effective as embodiments of the present invention.

According to the present invention, the generation of greenhouse gases can be reduced by supplying carbon-free fuel.

The overall configuration of a CFB boiler (circulating fluidized bed boiler) is shown. 4 schematically shows a configuration example of a start-up burner as a hybrid fuel supply unit;

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. The scales and shapes of the illustrated parts are set for convenience in order to facilitate explanation, and should not be construed as limiting unless otherwise specified. The embodiments are illustrative and do not limit the scope of the invention in any way. Not all features or combinations thereof described in the embodiments are essential to the invention.

The combustion device of the present invention is any device that supplies and burns fuel into a combustion chamber in which a fluid material flows. For example, when the combustion apparatus is configured as a boiler, the combustion apparatus can be configured as a BFB boiler or a CFB boiler that burns fuel via a fluidized bed or a fluidized bed formed of a fluid material such as silica sand flowing in the combustion chamber. In this embodiment, an example in which the combustion device is configured as a CFB boiler will be mainly described.

Fig. 1 shows the overall configuration of a CFB boiler (circulating fluidized bed boiler) as a combustion device. The CFB boiler includes a combustion section 1 that supplies and burns fuel in a furnace 11 in which a fluid material such as silica sand flows, a steam generation section 2 that generates steam from water by the heat generated in the combustion section 1, and a furnace 11 Fluid material circulation unit 3 that collects the fluid material that has flowed out and returns it to furnace 11 , air that is supplied to combustion unit 1 , water that is supplied to steam generation unit 2 , and steam that is generated by steam generation unit 2 . is heated by the high-temperature exhaust gas from the combustion unit 1; a dust collector 5 separates and collects soot and dust in the exhaust gas from the heat transfer unit 4; It is equipped with a chimney 6 that discharges the exhaust gas into the atmosphere.

The combustion section 1 has a furnace 11 as a combustion chamber. The furnace 11 has a vertically elongated cylindrical shape, and has a tapered bottom in order to increase the density of the solid fuel and the fluidized material to enable efficient combustion. The bottom portion of the furnace 11 may not be tapered, and the furnace 11 may be formed in a cylindrical shape with a substantially constant cross-sectional shape from the top to the bottom. A region indicated by A at the bottom of the furnace 11 indicates a fluidized bed (also called fluidized bed or sand layer) formed by a high-density fluidized material. In the fluidized bed A, a powdered or particulate fluidized material such as silica sand is fluidized by air as a fluidized fluid supplied from the bottom of the furnace 11 . The fuel introduced into the fluidized bed A is efficiently combusted by repeatedly contacting the high-temperature fluidizing material and air so as to be stirred therein.

In addition, since the fluidized material rises in the furnace 11 due to the ascending air current generated by combustion, the fluidized material also exists in the free board B, which is the space above the fluidized bed A. The density of the fluidized material in the freeboard B is lower than the density of the fluidized material in the fluidized bed A, and decreases toward the upper side of the furnace 11 . In the freeboard B, the fuel that has not been completely burned in the fluidized bed A is burned while coming into contact with the floating fluidized material. Silica sand was exemplified as the fluidizing material, but any material may be used as long as it functions as a medium for transferring heat to the fuel while maintaining a solid state without burning even in the high-temperature furnace 11 and flowing. Sand, stones such as limestone, and ash may also be used.

At the bottom of the furnace 11, a perforated plate (also called a dispersion plate) 121 is provided as a fluid permeable part made of a porous material that allows fluid including air to pass through. The air box 122, which is a space directly below the perforated plate 121, supplies pressurized air supplied from the first blower 71 as a blower via the first flow control valve 71A into the furnace 11 via the perforated plate 121. It constitutes a flowing fluid supply section (air supply section). The pressurized air supplied to the bottom of the furnace 11 by the wind box 122 fluidizes the fluid material to form the fluidized bed A and is used to burn the fuel in the fluidized bed A or the freeboard B. In addition, in order to promote the combustion of fuel in the freeboard B and suppress the generation of harmful substances such as dioxins and carbon monoxide due to incomplete combustion, the second blower 72 as a blower is operated through the second flow control valve 72A. to supply pressurized air into the freeboard B. In this embodiment, the perforated plate 121 is used as an example to explain the fluid permeable portion. It may be formed from a number of plates with slits for supplying flowing fluid into the furnace 11 .

In order to circulate the fluidized material in the fluidized bed A, an external circulation mechanism 13 having a circulation path outside the furnace 11 is provided. The external circulation mechanism 13 includes an extraction tube 131 that communicates with the bottom of the furnace 11 and can extract a part of the fluidized material in the fluidized bed A, and controls the opening and closing of the extraction tube 131 to control the flow rate of the fluidized material, that is, the extraction tube. An on-off valve 132 capable of adjusting the amount of the fluidized material withdrawn by the extraction pipe 131, a fluidized material conveyor 133 such as a bucket conveyor that conveys upward the fluidized material extracted by the extraction pipe 131, and corresponding to the upper part of the fluidized bed A A fluid material silo 134 is provided on the outer periphery of the furnace 11 and receives the fluid material conveyed by the fluid material conveyer 133 , and a fluid material re-injection unit 135 reintroduces the fluid material stored in the fluid material silo 134 into the furnace 11 . Prepare.

The extraction pipe 131, the on-off valve 132, the fluid material conveyor 133, the fluid material silo 134, and the fluid material re-injection unit 135 constitute a fluid material circulation path that connects the bottom surface and the side surface of the furnace 11 outside the furnace 11. . That is, the fluid material extracted from the bottom surface of the furnace 11 by the extraction pipe 131 passes through the on-off valve 132, the fluid material conveyor 133, and the fluid material silo 134, and is discharged from the side surface of the furnace 11 by the fluid material re-injection unit 135. It is put into the fluidized bed A again.

The furnace wall, which is the side wall of the furnace 11, has a fluidized material supply unit 14 for supplying a fluidized material for forming the fluidized bed A into the furnace 11 when the CFB boiler is started, and a fluidized material supply unit 14 for mainly burning in the fluidized bed A. A solid fuel supply unit 15 is provided for supplying the solid fuel of . The fluid material supply unit 14 includes a funnel-shaped fluid material hopper 141 that stores the fluid material, and a fluid material feeder 142 that supplies the fluid material discharged from the bottom of the fluid material hopper 141 into the furnace 11 . A desired amount of the fluid material is fed into the furnace 11 by controlling the rotational speed of the fluid material feeder 142 . The solid fuel supply unit 15 includes a funnel-shaped solid fuel hopper 151 that stores solid fuel, and a solid fuel feeder 152 that supplies the solid fuel discharged from the bottom of the solid fuel hopper 151 into the furnace 11 . A desired amount of solid fuel is fed into the furnace 11 by controlling the rotational speed of the solid fuel feeder 152 .

The solid fuel supplied into the furnace 11 by the solid fuel supply unit 15 is not particularly limited, but examples include various types of coal such as anthracite, bituminous coal, lignite, biomass, sludge, and waste materials. In the CFB boiler, high combustion efficiency can be achieved by using the high-temperature fluid material that flows within the furnace 11 as a medium, so that even low-quality fuel and flame-retardant fuel can be efficiently burned. The solid fuel mentioned above is a carbon-containing fuel that contains carbon, and the solid fuel supply unit 15 constitutes a carbon-containing fuel supply unit that supplies the carbon-containing fuel into the furnace 11 . In addition, although there are few concrete examples at present, when carbon-free solid fuel becomes available, the solid fuel supply unit 15 that supplies such carbon-free fuel into the furnace 11 is replaced by the carbon-free fuel supply unit configure.

In addition to or instead of the solid fuel supply unit 15 , a carbon-free fuel supply unit 16 that supplies non-solid or fluid (liquid or gaseous) carbon-free fuel into the furnace 11 is provided in each part of the combustion unit 1 . Four installation examples of the carbon-free fuel supply unit 16 are shown below, but the location and installation mode of the carbon-free fuel supply unit 16 are not limited to these. The number of carbon-free fuel supply units 16 is not limited to four, and the effect of this embodiment, such as greenhouse gas suppression, which will be described later, can be obtained if there is at least one. Five or more carbon-free fuel supply units 16 may be provided. Further, although ammonia is used as an example of a non-solid carbon-free fuel in the following description, other fuels such as hydrogen may be used.

The carbon-free fuel supply unit 16A according to the first installation mode supplies the wind box 122 with ammonia as the carbon-free fuel. Ammonia supplied to the wind box 122 is mixed with pressurized air supplied from the first blower 71 into the wind box 122, passes through the perforated plate 121, and is supplied into the fluidized bed A from below. . By supplying ammonia as a non-solid fuel together with pressurized air to agitate the fluidized material and solid fuel in the fluidized bed A, the fluidized material, solid fuel, pressurized air, and ammonia are mixed, so it is known as flame retardant. Ammonia can be efficiently burned. The carbon-free fuel supply unit 16A includes a storage unit 161A that stores ammonia in a gaseous or liquid non-solid state, and an ammonia stored in the storage unit 161A in a gaseous or liquid non-solid state into the wind box 122. It has an injection device 162A that injects.

The carbon-free fuel supply unit 16B according to the second installation mode supplies ammonia as a carbon-free fuel into the fluidized bed A from the side of the fluidized bed A (fluidized material at the bottom of the furnace 11) on the perforated plate 121. supply. Ammonia directly supplied into the fluidized bed A is mixed with the fluid material, solid fuel, and pressurized air in the fluidized bed A and efficiently combusted. The carbon-free fuel supply unit 16B includes a storage unit 161B that stores ammonia in a gaseous or liquid non-solid state, and ammonia stored in the storage unit 161B in a gaseous or liquid non-solid state into the fluidized bed A. It has an injector 162B for injecting. Here, ammonia can be efficiently injected into the fluidized bed A by providing the tip of the injection device 162B so as to be inserted into the fluidized bed A from the side. The injection device 162B may be configured as a burner that mixes ammonia with air and burns it. In this case, the tip of the injection device 162B serves as the crater of the burner and ejects a flame by combustion of ammonia into the fluidized bed A. . Such a burner as the carbon-free fuel supply unit 16B can be configured, for example, as a lance burner or a burner lance, and a carbon-free fuel such as ammonia is supplied to the side of the fluidized material (that is, the fluidized bed A) at the bottom of the furnace 11. Burn.

The position of the injection port as the tip of the injection device 162B of the carbon-free fuel supply unit 16B may be anywhere as long as it faces the fluidized bed A. For example, when the height of the furnace 11 is about 30 m, the typical height of the fluidized bed A is about 1.5 m. is preferably 0.5 m. Also, when expressed as a percentage of the height of the furnace 11, a typical height of the fluidized bed A of 1.5 m corresponds to 5.0% of 30 m, whereas the height of the injection port of the injection device 162B is preferably 1.0. %-4.0%, more preferably 1.5%-2.5% (0.5m above corresponds to 1.7% of 30m).

In addition, by providing the position of the injection port as the tip of the injection device 162B of the carbon-free fuel supply unit 16B constituted by a burner or the like at a height of less than 1.5 m from the bottom of the furnace 11, suboxidation due to combustion of ammonia The effect of reducing the generation and emission of nitrogen (N ₂ O: also called dinitrogen oxide or dinitrogen monoxide) was confirmed. It is believed that the nitrous oxide generated near the position of the injection port of the carbon-free fuel supply portion 16B is reduced and converted into nitrogen while passing through the main combustion region above it. In order to enhance the reduction effect of nitrous oxide reduction, the position of the injection port of the carbon-free fuel supply unit 16B may be further lowered, for example, the height of less than 1.0 m from the bottom of the furnace 11. , and more preferably less than 0.5 m from the bottom of the furnace 11 .

Similarly, the position of the injection port as the tip of the injection device 162B of the carbon-free fuel supply unit 16B constituted by a burner or the like is set at a distance of 1.5 m or more from the bottom surface of the furnace 11 (and preferably below the upper surface of the fluidized bed A). It was confirmed that the installation at a height can reduce the generation and emission of nitrogen oxides (NOx) due to combustion of ammonia. It is believed that nitrogen oxides generated at the bottom of the furnace 11 react with ammonia supplied from a burner or the like and are reduced to nitrogen. Pressurized air from a second blower 72 typically installed at a height of about 3.0 m to 4.0 m from the bottom of the furnace 11 in order to obtain the effect of reducing nitrogen oxides while maintaining complete combustion of the supplied ammonia. (Although pressurized air is supplied above the fluidized bed A in FIG. 1, in practice, pressurized air may be supplied from the side of the fluidized bed A) Carbon-free fuel below It is preferable to install the injection port of the supply part 16B. In order to obtain the effect of completely burning ammonia and reducing nitrogen oxides at the same time, the injection port of the carbon-free fuel supply unit 16B may be provided below the supply port of the pressurized air. For a typical pressurized air supply port (about 3.0 m to 4.0 m high), the injection port of the carbon-free fuel supply unit 16B is, for example, 2.0 m or more from the bottom of the furnace 11. Well, it may be 3.0 m or more from the bottom of the furnace 11 .

For effective reduction of N2O and NOx emissions, burners in the carbon _- free fuel supply 16B less than 1.5m (or less than 1.0m, less than 0.5m) and 1.5m or more (or , 2.0 m or more, 3.0 m or more) is preferably installed side by side with the burner of the carbon-free fuel supply section 16B. By individually adjusting the supply amount and combustion amount of carbon-free fuel such as ammonia in each burner, the emissions of N ₂ O and NOx in the furnace 11 can be minimized or optimized.

The carbon-free fuel supply unit 16C according to the third installation mode is configured integrally with a starting burner to be described later, and the carbon-free fuel is supplied downward from above the fluidized bed A toward the surface (upper surface) of the fluidized bed A. supply ammonia as Ammonia supplied from the carbon-free fuel supply unit 16C is mixed with the fluid material, solid fuel, and pressurized air flowing on the surface of the fluidized bed A and efficiently combusted. Here, the carbon-free fuel supply unit 16A that supplies ammonia from below the fluidized bed A, the carbon-free fuel supply unit 16B that supplies ammonia from the side of the fluidized bed A, and the ammonia from above the fluidized bed A By combining at least two of the carbon-free fuel supply parts 16C, ammonia can be injected from different directions into the fluid material, the solid fuel, and the pressurized air flowing in each part of the fluidized bed A to efficiently mix them. Ammonia, which is known to be flammable, can be efficiently burned in each part of the fluidized bed A.

The carbon-free fuel supply unit 16C includes a storage unit 161C that stores ammonia in a gaseous or liquid non-solid state, and the ammonia stored in the storage unit 161C in a gaseous or liquid non-solid state and injects it into the furnace 11. and an injector 162C. Here, the injection device 162C also functions as a starting burner, which will be described later, and is inclined downward so that the surface of the fluidized bed A can be directly heated by the flame jetted from its tip. Although the specific configuration will be described later, a CFB boiler is generally provided with a start-up burner for starting, and in this embodiment, the existing start-up burner is used as a carbon-free fuel supply unit 16C for supplying ammonia. can also be used.

The position of the injection port as the tip of the injector 162C of the carbon-free fuel supply 16C is determined by the position of the existing start-up burner. For example, if the furnace 11 has a height of about 30 m, the typical height of the start-up burners is about 2.0 m and is above the fluidized bed A, which is about 1.5 m high. The carbon-free fuel supply unit 16C may be provided separately from the starting burner, in which case the height of the injection port of the injection device 162C can be freely set. For example, 6.0% or more of the height of the furnace 11 (1.8 It is preferable to provide the injection port of the injection device 162C at a height of 162C or more. If the downward inclination angle of the injection device 162C is increased, ammonia can be injected onto the surface of the fluidized bed A even if the installation height is large.

The carbon-free fuel supply unit 16D according to the fourth installation mode supplies ammonia as a carbon-free fuel into the freeboard B in the upper part of the furnace 11. Ammonia supplied into the freeboard B burns unburned substances derived from solid fuels that have not been completely burned in the fluidized bed A, thereby preventing the generation of harmful substances such as dioxins and carbon monoxide due to incomplete combustion. Suppress. In particular, in order not to generate dioxins in the freeboard B, it is important to keep the temperature above about 800°C. A high temperature of about 800° C. or more can be maintained even at the free board B which is away from.

Ammonia also functions as a reducing agent, reducing nitrogen oxides (NOx), which are air pollutants that may be generated by combustion in the furnace 11, to harmless nitrogen and water. By supplying ammonia from the carbon-free fuel supply part 16D to the freeboard B before the exhaust gas exits the furnace 11 after combustion in the lower part of the furnace 11, nitrogen oxides in the exhaust gas can be effectively removed.

The carbon-free fuel supply unit 16D includes a storage unit 161D that stores ammonia in a gaseous or liquid non-solid state, and the ammonia stored in the storage unit 161D in a gaseous or liquid non-solid state in the freeboard B. It has an injection device 162D for injection. The injection device 162D may be configured as a burner that mixes and burns ammonia with air, and in this case, the tip of the injection device 162D serves as the crater of the burner and ejects flames from combustion of ammonia into the freeboard B. .

The position of the injection port as the tip of the injection device 162D of the carbon-free fuel supply unit 16D may be anywhere as long as it faces the freeboard B. For example, when the height of the furnace 11 is about 30 m, the freeboard B is formed above the fluidized bed A of about 1.5 m. However, in the portion near the surface of the fluidized bed A, the powdered or particulate fluidized material and solid fuel are burning while vigorously moving. It is preferable to keep the injection port of the device 162D sufficiently away from the surface of the fluidized bed A. On the other hand, if the position of the injection port of the injection device 162D is too high, the exhaust gas will come out of the furnace 11 before dioxins and nitrogen oxides are sufficiently removed by ammonia, which is not preferable. Considering these points, the height of the injection port of the injection device 162D is preferably within a range of 50% (15m) to 70% (21m) of the height of the furnace 11 (30m).

As described above, by providing the carbon-free fuel supply units 16A to 16D at a plurality of different positions in the vertical direction, which is the height direction of the furnace 11, the combustion sites of ammonia, which is known as flame retardancy, are dispersed and the overall High combustion efficiency can be achieved. Further, by adopting a configuration in which ammonia is gradually burned in each part of the furnace 11 in this way, it is possible to increase the supply amount of ammonia as a whole while maintaining high combustion efficiency. In other words, many conventional carbon-containing fuels, such as carbon-based coal, can be replaced by non-carbon-containing fuels such as ammonia and hydrogen. Since carbon-free fuels do not generate carbon-containing greenhouse gases such as carbon dioxide when burned, they can reduce adverse effects on the global environment as global warming progresses.

Next, a start burner (denoted as a start burner 16C) configured integrally with the carbon-free fuel supply section 16C will be described. The starting burner 16C is provided with a carbon-containing fuel storage section 163C that stores heavy oil as a carbon-containing fuel in parallel with a carbon-free fuel storage section 161C that stores ammonia as a carbon-free fuel. A carbon-free fuel control valve 164C is provided between the carbon-free fuel reservoir 161C and the injector 162C to control the amount of ammonia supplied from the carbon-free fuel reservoir 161C to the injector 162C. A carbon-containing fuel control valve 165C is provided between the reservoir 163C and the injector 162C to control the amount of heavy oil supplied from the carbon-containing fuel reservoir 163C to the injector 162C.

The mode switching unit 166C controls the carbon-free fuel control valve 164C and the carbon-containing fuel control valve 165C, and complementarily switches between open and closed states. In a first mode, with carbon-free fuel control valve 164C open and carbon-free fuel control valve 165C closed, injector 162C supplies ammonia from carbon-free fuel reservoir 161C into furnace 11 . In a second mode in which carbon-free fuel control valve 164C is closed and carbon-containing fuel control valve 165C is open, injector 162C supplies heavy oil into furnace 11 from carbon-containing fuel reservoir 163C. Specifically, heavy oil mixed with air is combusted in an injection device 162C configured as a burner, and the tip of the injection device 162C serves as the crater of the burner and ejects flames from the combustion of the heavy oil into the furnace 11.

The mode switching unit 166C switches to the second mode when the CFB boiler is started, and switches to the first mode after the CFB boiler is started. When starting up the CFB boiler, a fluid material such as silica sand for forming the fluidized bed A is supplied from the fluid material supply unit 14 into the furnace 11 . At this time, a solid fuel such as coal may also be supplied into the furnace 11 from the solid fuel supply unit 15, or ammonia may be supplied from the carbon-free

fuel supply units

16A, 16B, and 16D other than the carbon-free fuel supply unit 16C. A carbon-free fuel such as hydrogen or hydrogen may also be supplied into the furnace 11 . The injection device 162C, which operates in the second mode when the CFB boiler is started, heats the fluid material supplied from the fluid material supply unit 14 with flames generated by combustion of heavy oil. Here, since the injection device 162C is provided inclined downward, the surface of the fluidized bed A formed by the fluidized material is directly heated, and the temperature of the fluidized bed A and the inside of the furnace 11 is efficiently raised. Since the starting burner 16C heats the sand-like fluidized bed A from above in this manner, it is also called a burner on sand.

After the fluidized bed A and the inside of the furnace 11 have sufficiently heated up the CFB boiler, that is, after the solid fuel can be burned in the fluidized bed A, the mode switching unit 166C switches to the first mode. The injector 162C operating in the first mode injects carbon-free fuel such as ammonia or hydrogen to the surface of the fluidized bed A from its tip. As described above, the startup burner 16C functions as a carbon-containing fuel supply section that supplies heavy oil as carbon-containing fuel in the second mode at startup, and ammonia and carbon-free fuel as carbon-free fuel in the first mode after startup. It is a hybrid fuel supply unit that functions as a carbon-free fuel supply unit that supplies hydrogen or the like. A conventional start-up burner is stopped after the temperature is raised by heavy oil or the like at start-up, but according to the present embodiment, the start-up burner can be effectively used as a carbon-free fuel supply section even after start-up.

FIG. 2 schematically shows a configuration example of the starting burner 16C as a hybrid fuel supply section. Injector 162C of start-up burner 16C receives carbon-free fuel receiving portion 167C as carbon-free fuel from carbon-free fuel reservoir 161C and heavy oil as carbon-containing fuel from carbon-containing fuel reservoir 163C. A contained fuel receiving portion 168C is provided.

The combustion section 1 of the CFB boiler has been described in detail above. Next, the configuration of the CFB boiler other than the combustion section 1 will be described. The steam generating unit 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 to heat it, A steam pipe 24 is provided for discharging steam generated from water heated in the water pipe 23 from the drum 21 as the output of the CFB boiler. The water supply pipe 22 meanders in the heat transfer section 4 through which the high-temperature exhaust gas of the combustion section 1 passes to form an economizer that preheats the water supply, and the steam pipe 24 is a heat transfer section through which the high-temperature exhaust gas of the combustion section 1 passes. A superheater that superheats steam is configured by meandering inside 4 . Similarly, the pressurized air supplied into the furnace 11 by the first blower 71 and the second blower 72 is also preheated by the high-temperature exhaust gas inside the heat transfer section 4 .

The fluidizing material circulation unit 3 includes a cyclone 31 that separates and collects the fluidizing material from the exhaust discharged from the upper part of the furnace 11 and a seal pot 32 that returns the fluidizing material collected by the cyclone 31 into the furnace 11. . The cyclone 31 is a cyclone-type powder separator having a generally cylindrical upper portion and a generally conical lower portion, and generates an air flow spirally descending along the inner wall. The fluid material contained in the exhaust gas from the furnace 11 is collected by coming into contact with the inner wall of the cyclone 31 and falling down while spirally descending along the airflow. The exhaust gas contains not only the fluid material but also the ammonia supplied from the carbon-free fuel supply units 16A to 16D. Therefore, even if nitrogen oxides remain in the exhaust gas, they can be efficiently removed by ammonia vigorously moving in the cyclone 31 . Furthermore, the cyclone 31 promotes contact between the carbon-free fuel ammonia as an unburned matter remaining in the exhaust gas and the fluidizing material, in other words, the cyclone 31 functions as an ammonia mixer or a carbon-free fuel agitator. , complete combustion of ammonia as unburned content can be expected. From the viewpoint of making the cyclone 31 function as an ammonia mixer, the carbon-free fuel supply units 16A to 16D are preferably installed upstream of the cyclone 31 in the exhaust flow.

A seal pot 32 provided below the cyclone 31 is filled with a fluid material to prevent backflow of unburned gas from the furnace 11 to the cyclone 31. The fluid material filled in the seal pot 32 is pushed out by the weight of the fluid material newly collected by the cyclone 31 and is gradually returned into the furnace 11 .

The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that the embodiments are examples, and that various modifications can be made to combinations of each component and each treatment process, and such modifications are also within the scope of the present invention.

Although a CFB boiler has been described as an example of a boiler in the embodiments, the present invention can also be applied to a BFB boiler (a bubbling fluidized bed boiler). The configuration of the BFB boiler is the same as that of the CFB boiler except that it does not include the fluid material circulation unit 3 that collects the fluid material that has flowed out of the furnace 11 and returns it to the inside of the furnace 11 .

Note that the functional configuration of each device described in the embodiments can be realized by hardware resources or software resources, or by cooperation between hardware resources and software resources. Processors, ROMs, RAMs, and other LSIs can be used as hardware resources. Programs such as operating systems and applications can be used as software resources.

1 Combustion section, 2 Steam generation section, 3 Fluid material circulation section, 4 Heat transfer section, 11 Furnace, 13 External circulation mechanism, 14 Fluid material supply section, 15 Solid fuel supply section, 16 Carbon-free fuel supply section, 16C Start Burner, 31 cyclone, 32 seal pot, 121 perforated plate, 122 wind box, 166C mode switching part, 167C carbon-free fuel receiving part, 168C carbon-containing fuel receiving part.

Claims

A combustion device for supplying and burning fuel in a combustion chamber in which a fluid material flows,
A combustion apparatus comprising a carbon-free fuel supply that supplies a carbon-free fuel that does not contain carbon into the combustion chamber.
The combustion apparatus according to claim 1, further comprising a carbon-containing fuel supply unit that supplies carbon-containing fuel containing carbon into the combustion chamber.
the carbon-free fuel supply unit and the carbon-containing fuel supply unit are configured as an integrated hybrid fuel supply unit;
3. The combustion device of claim 2, wherein said hybrid fuel supply comprises a carbon-free fuel receiving portion for receiving said carbon-free fuel and a carbon-containing fuel receiving portion for receiving said carbon-containing fuel.
4. The hybrid fuel supply unit according to claim 3, further comprising a mode switching unit for switching between a first mode of supplying the carbon-free fuel into the combustion chamber and a second mode of supplying the carbon-containing fuel into the combustion chamber. combustion device.
The combustion apparatus according to claim 4, wherein the mode switching unit switches to the second mode when the combustion apparatus is started, and switches to the first mode after the combustion apparatus is started.
a fluid permeable part provided at the bottom of the combustion chamber and allowing fluid to pass therethrough;
a flowing fluid supply unit that supplies air for flowing the fluid material through the fluid permeable portion into the combustion chamber;
The carbon-free fuel supply section supplies the carbon-free fuel to the fluid material on the fluid permeable section, and supplies the carbon-free fuel, which is a fluid, together with the air through the fluid permeable section. 6. The combustion device according to any one of claims 1 to 5, supplying into the combustion chamber.
The combustion apparatus according to any one of claims 1 to 5, wherein the carbon-free fuel supply unit supplies the carbon-free fuel from the side to the fluid material at the bottom of the combustion chamber.
The combustion apparatus according to claim 7, wherein the carbon-free fuel supply section is a burner that burns the carbon-free fuel at the side of the fluid material at the bottom of the combustion chamber.
The combustion device according to claim 8, wherein the burner is provided at a height of less than 1.5m from the bottom of the combustion chamber.
The combustion device according to claim 8, wherein the burner is provided at a height of 1.5 m or more from the bottom surface of the combustion chamber.
The combustion apparatus according to any one of claims 1 to 5, wherein the carbon-free fuel supply unit supplies the carbon-free fuel to a plurality of positions with different heights in the combustion chamber.
The combustion apparatus according to any one of claims 1 to 5, wherein the carbon-free fuel is a non-solid fuel.
The combustion device according to claim 12, wherein the non-solid fuel is at least one of ammonia and hydrogen.
The combustion apparatus according to any one of claims 1 to 5, further comprising a fluid material circulation unit that collects the fluid material that has come out of the combustion chamber and returns it to the combustion chamber.
The combustion apparatus according to any one of claims 1 to 5, wherein the combustion apparatus is a circulating fluidized bed boiler.
a combustion unit that supplies and burns fuel into a combustion chamber in which the fluid material flows;
a carbon-free fuel supply unit that supplies a carbon-free fuel that does not contain carbon into the combustion chamber;
A boiler comprising: a steam generating section for generating steam from water by heat generated in the combustion section.
A combustion method in which fuel is supplied and burned in a combustion chamber in which a fluid material flows,
A combustion method comprising a carbon-free fuel supply step of supplying carbon-free fuel containing no carbon into said combustion chamber.