Boilers and plants

Abstract

To provide a boiler capable of suppressing the amount of carbon dioxide discharged therefrom and suppressing the fuel storage volume from becoming larger.SOLUTION: The boiler comprises a furnace, and a fuel feeder for feeding metallic magnesium into the furnace as fuel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a boiler and a plant including the boiler.

Background Art

[0002] In recent years, in some boilers, efforts have been made to shift away from fossil fuels (decarbonization) for the purpose of reducing emissions of carbon dioxide, which is a typical greenhouse gas. For example, Patent Document 1 discloses a fluidized bed boiler that burns a fuel containing an alkaline component such as biomass fuel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Biomass fuel is considered carbon neutral because it captures carbon dioxide during the growth process of biomass, but carbon dioxide is emitted during the combustion of biomass fuel.

[0005] Examples of fuels that do not emit carbon dioxide during combustion include hydrogen and ammonia. However, when applying hydrogen or ammonia as a fuel, hydrogen and ammonia, which are gases at room temperature, require a larger storage capacity compared to fossil fuels and biomass fuels.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a boiler capable of suppressing both carbon dioxide emissions and an increase in the fuel storage capacity.

Means for Solving the Problems

[0007] To achieve the above objective, the boiler according to this disclosure comprises a furnace and a fuel feeding device for feeding metallic magnesium into the furnace as fuel. [Effects of the Invention]

[0008] The boiler of this disclosure can suppress both carbon dioxide emissions and the need for a large fuel storage capacity. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram schematically shows the configuration of a plant equipped with a boiler according to the first embodiment. [Figure 2] This diagram schematically shows the configuration of a fuel feeding device according to the first embodiment. [Figure 3] This diagram schematically shows the configuration of a plant equipped with a boiler according to the second embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, a boiler according to an embodiment of the present disclosure will be described with reference to the drawings. Such embodiments represent one aspect of the present disclosure and are not limiting, and can be modified at will within the scope of the technical idea of ​​the present disclosure.

[0011] <First Embodiment> (composition) The configuration of the boiler 1 according to the first embodiment will now be described. Figure 1 is a schematic diagram showing the configuration of a plant 100 equipped with the boiler 1 according to the first embodiment. Figure 2 is a schematic diagram showing the configuration of a fuel feeding device 4 according to the first embodiment. As illustrated in Figure 1, the plant 100 is equipped with the boiler 1. The boiler 1 includes a furnace 2 and a fuel feeding device 4 for feeding metallic magnesium Fa into the furnace 2 as fuel. The boiler 1 generates high-temperature combustion gas G by burning the metallic magnesium Fa fed into the furnace 2, and generates superheated steam S by recovering heat from this high-temperature combustion gas G.

[0012] In the first embodiment, as illustrated in Figure 2, the furnace 2 has a cylindrical shape extending along the vertical direction D1, and a combustion space 3 for burning metallic magnesium Fa is formed inside. As will be described later, the combustion space 3 includes a fluidized bed 6.

[0013] In the first embodiment, as illustrated in Figure 1, the boiler 1 includes a fluidized sand storage tank 10 for storing fluidized sand B supplied to the fluidized bed 6, and a fluidized sand line 12 for transporting the fluidized sand B to the furnace 2. The furnace 2 is configured to supply fluidized sand B to the fluidized bed 6 by introducing the fluidized sand B stored in the fluidized sand storage tank 10 into the fluidized sand line 12 which opens to the fluidized bed 6. As illustrated in Figure 2, an extraction pipe 15 for extracting fluidized sand B from the fluidized bed 6 is connected to the bottom 14 of the furnace 2.

[0014] In the first embodiment, as illustrated in Figure 2, an air nozzle 16 for supplying combustion air A to the combustion space 3 is provided at the bottom 14 of the furnace 2. The fluidized bed 6 is formed when the fluidized sand B in the combustion space 3 is fluidized by the combustion air A blown into the combustion space 3. The metallic magnesium Fa introduced into the furnace 2 is stirred and mixed with the combustion air A in the fluidized bed 6 and then combusted. The combustion gas G generated by the combustion of metallic magnesium Fa moves to the upper space 7 (freeboard) above the fluidized bed 6 in the combustion space 3. The combustion gas G is then discharged to the outside of the furnace 2 via a combustion gas line 21 connected to the upper part of the furnace wall 18 of the furnace 2.

[0015] In the first embodiment, as illustrated in Figure 1, the boiler 1 includes a heat exchanger 20 (superheater) located in the fluidized bed 6, which generates superheated steam S by exchanging heat between steam or feedwater and combustion gas G. In the embodiment illustrated in Figure 1, the plant 100 includes a steam turbine 22 that is rotationally driven by the superheated steam S generated by the heat exchanger 20, and a generator 24 that converts the rotational energy of the steam turbine 22 into electrical energy. Although not shown, in some embodiments, the boiler 1 further includes heat exchangers (reheaters, economizers) for recovering heat from the combustion gas G flowing through the combustion gas line 21. This disclosure does not limit the plant 100 to a power plant. The superheated steam S generated by the boiler 1 may be used for purposes other than power generation.

[0016] As described above, the fuel feeding device 4 feeds metallic magnesium Fa into the furnace 2 as fuel. In the first embodiment, as illustrated in Figure 1, the boiler 1 further includes a metallic magnesium storage tank 70 for storing metallic magnesium Fa. The method for transporting metallic magnesium Fa from the metallic magnesium storage tank 70 to the fuel feeding device 4 is not particularly limited.

[0017] This section describes metallic magnesium Fa. Metallic magnesium Fa contains magnesium at a weight ratio of 50% or more. More specifically, metallic magnesium Fa contains magnesium at a weight ratio of 90% or more, preferably 99% or more, and more preferably 99.9% or more. Metallic magnesium Fa contains at least one of elemental magnesium and magnesium alloys. Metallic magnesium Fa contains at least one granular, crumbly, plate-like, or ingot-like solid material. In the first embodiment, metallic magnesium Fa contains granular solid material, which is granular with a diameter of 2 mm or more.

[0018] In some embodiments, the metallic magnesium Fa contains solid material in the form of scraps, plates, or ingots, with a particle size of 2 mm or larger. Such solid material is, for example, the material that does not pass through when sieved using a sieve with a mesh size of 2 mm or larger.

[0019] In the first embodiment, the fuel that the fuel supply device 4 supplies to the furnace 2 further includes biomass Fb in addition to magnesium metal Fa. Biomass Fb is a bio-derived organic resource, for example, thinned wood, waste wood, driftwood, grasses, waste, sludge, and the like. Biomass Fb is also agitated and mixed with combustion air A in the fluidized bed 6 and burned in the same manner as magnesium metal Fa. Then, combustion gas G is generated by the combustion of biomass Fb. That is, in the plant 100 according to the first embodiment, superheated steam S is generated in the boiler 1 using magnesium metal Fa and biomass Fb as fuels, and the generated superheated steam S is used to rotationally drive the steam turbine 22, and power is generated by the generator 24. Note that the method of transporting biomass Fb to the fuel supply device 4 is not particularly limited. For example, biomass Fb is transported to the fuel supply device 4 by a crane. The boiler 1 may include a silo or a stockyard for storing biomass Fb.

[0020] In the first embodiment, as illustrated in FIG. 2, the fuel supply device 4 includes a biomass supply pipe 30 for supplying biomass Fb to the furnace 2 and a magnesium metal supply pipe 32 for supplying magnesium metal Fa to the furnace 2.

[0021] The biomass supply pipe 30 connects the first inlet 34 into which biomass Fb is introduced and the furnace 2. In the form illustrated in FIG. 2, the boiler 1 further includes a hopper 36. The biomass supply pipe 30 connects the hopper 36 and the furnace 2. More specifically, the biomass supply pipe 30 connects the discharge port of the hopper 36, which is the first inlet 34, and the fuel port 40 formed in the furnace wall 18 of the furnace 2. The biomass Fb introduced into the biomass supply pipe 30 via the hopper 36 flows through the biomass supply pipe 30 toward the furnace 2, passes through the fuel port 40, and is supplied to the combustion space 3. In the form illustrated in FIG. 2, the hopper 36 includes a first opening / closing valve 35 that opens and closes the first inlet 34.

[0022] The magnesium metal supply pipe 32 connects the second inlet 42 into which magnesium metal Fa is introduced and the biomass supply pipe 30. In the form illustrated in FIG. 2, the boiler 1 further includes a hopper 44 for Mg provided separately from the hopper 36. The magnesium metal supply pipe 32 connects the hopper 44 for Mg and the biomass supply pipe 30. More specifically, the magnesium metal supply pipe 32 connects the discharge port of the hopper 44 for Mg, which is the second inlet 42, and the confluence port 46 formed in the biomass supply pipe 30. The confluence port 46 is located between both ends of the biomass supply pipe 30 in the direction in which the biomass supply pipe 30 extends. The magnesium metal Fa introduced into the magnesium metal supply pipe 32 via the hopper 44 for Mg flows through a part of the magnesium metal supply pipe 32 and the biomass supply pipe 30 toward the furnace 2, passes through the fuel port 40, and is supplied to the combustion space 3. In the form illustrated in FIG. 2, the hopper 44 for Mg includes a second opening / closing valve 43 that opens and closes the second inlet 42.

[0023] In the first embodiment, as illustrated in FIGS. 1 and 2, the boiler 1 further includes a control device 50, a hydrogen combustion device 52, and a hydrogen concentration acquisition device 54.

[0024] The control device 50 is a computer such as an electronic control device, and includes a processor such as a CPU or GPU (not shown), a memory such as a ROM or RAM, and an I / O interface. The control device 50 realizes each functional unit included in the control device 50 by the processor operating (performing calculations, etc.) according to the instructions of the program loaded in the memory. As illustrated in FIG. 2, the control device 50 is electrically connected to each of the first opening / closing valve 35, the second opening / closing valve 43, the hydrogen combustion device 52, and the hydrogen concentration acquisition device 54. In some embodiments, the control device 50 is a cloud server provided in a cloud environment.

[0025] The hydrogen combustion device 52 is positioned above the fluidized bed 6 in the furnace 2. The hydrogen combustion device 52 burns hydrogen to prevent a large amount of hydrogen from accumulating in the upper part of the furnace 2. In the embodiment illustrated in Figure 2, the hydrogen combustion device 52 is positioned in the upper space 7 within the furnace 2, above the fuel port 40. The hydrogen combustion device 52 is configured to operate when a drive signal 51 is transmitted from the control device 50. Such a hydrogen combustion device 52 is, for example, a burner, and the flame of the burner can burn the hydrogen accumulating in the upper part of the furnace 2. The fuel supplied to the burner is not particularly limited and may be gas or heavy oil.

[0026] The hydrogen concentration acquisition device 54 is positioned above the fluidized bed 6 in the furnace 2. It acquires the concentration of hydrogen accumulating in the upper part of the furnace 2. In the configuration illustrated in Figure 2, the hydrogen concentration acquisition device 54 is positioned in the upper space 7 within the furnace 2, above the fuel port 40. The hydrogen concentration acquisition device 54 transmits the acquired hydrogen concentration 55 to the control device 50. When the hydrogen concentration 55 transmitted from the hydrogen concentration acquisition device 54 exceeds a preset concentration, the control device 50 transmits a drive signal 51 to the hydrogen combustion device 52, thereby driving the hydrogen combustion device 52. The preset concentration is, for example, a value of 50% or less of the lower limit of the explosion limit of hydrogen in the combustion space 3.

[0027] In the first embodiment, as illustrated in Figure 1, the boiler 1 further includes a fuel supply shutoff device 59. The fuel supply shutoff device 59 is configured to shut off the supply of fuel to the furnace 2 when the hydrogen concentration 55 obtained by the hydrogen concentration acquisition device 54 exceeds a set concentration. Specifically, as illustrated in Figure 2, the fuel supply shutoff device 59 includes a first on-off valve 35 and a second on-off valve 43. Each of the first on-off valve 35 and the second on-off valve 43 opens and closes according to an on-off instruction 57 transmitted from the control device 50. When the hydrogen concentration 55 transmitted from the hydrogen concentration acquisition device 54 exceeds the set concentration, the control device 50 transmits an on-off instruction 57 to each of the first on-off valve 35 and the second on-off valve 43 to close, and both the first on-off valve 35 and the second on-off valve 43 close.

[0028] (Effects / Actions) The operation and effects of the boiler 1 according to the first embodiment will now be described. Metallic magnesium Fa does not produce carbon dioxide when burned (2Mg + O2 → 2MgO). Furthermore, since metallic magnesium Fa is a solid at room temperature, the fuel storage capacity required for the metallic magnesium storage tank 70 can be reduced compared to hydrogen and ammonia, which are gases at room temperature. For this reason, according to the first embodiment, since the boiler 1 is configured so that metallic magnesium Fa is fed into the furnace 2 as fuel, both carbon dioxide emissions and the need for a large storage capacity in the metallic magnesium storage tank 70 can be suppressed.

[0029] Metallic magnesium Fa has a lower specific gravity compared to other practical metals, making it easy to fluidize with combustion air A blown into the furnace 2. According to the first embodiment, metallic magnesium Fa can be used as fuel in a boiler 1 in which a fluidized bed 6 is formed in the furnace 2. Furthermore, even if the metallic magnesium Fa contains granular solids with a diameter of 2 mm or more, the specific gravity of metallic magnesium Fa can be made to be about the same as that of fluidized sand B. Therefore, it is not necessary to increase the flow velocity of the combustion air A.

[0030] Metallic magnesium Fa has the property of burning when it reacts with moisture (Mg + H2O → MgO + H2). According to the first embodiment, since metallic magnesium Fa and biomass Fb are fed into the furnace 2 as fuel, metallic magnesium Fa reacts with the moisture contained in biomass Fb and burns, promoting combustion in the fluidized bed 6. In particular, if the proportion of moisture (moisture content) in biomass Fb is high, it has a significant impact on its combustibility. For this reason, if the moisture content exceeds the allowable limit on the boiler 1 side and it cannot be used as fuel, it is necessary to take measures such as installing a drying device in the plant 100 to reduce the moisture content before use. However, according to the first embodiment, since biomass Fb is fed into the furnace together with metallic magnesium Fa as fuel, metallic magnesium Fa actively removes moisture from biomass Fb and burns. Therefore, it is possible to ensure high combustibility regardless of the moisture content of biomass Fb. In other words, the range of effective utilization of biomass resources can be expanded.

[0031] When using metallic magnesium Fa and biomass Fb as fuel, it is preferable to provide separate inlets for metallic magnesium Fa and biomass Fb to prevent combustion of the metallic magnesium Fa and biomass Fb before they are introduced. According to the first embodiment, metallic magnesium Fa is introduced from a second inlet 42, which is separate from the first inlet 34 into which biomass Fb is introduced. This prevents the metallic magnesium Fa and biomass Fb from burning before they are introduced.

[0032] In the first embodiment, metallic magnesium Fa was introduced into the metallic magnesium supply pipe 32 via the Mg hopper 44, but this disclosure is not limited to this embodiment. Metallic magnesium Fa may be introduced into the metallic magnesium supply pipe 32 via a device other than the Mg hopper 44. Metallic magnesium Fa may also be introduced directly into the metallic magnesium supply pipe 32. In this case, the second inlet 42 is provided in the metallic magnesium supply pipe 32.

[0033] In the first embodiment, metallic magnesium Fa and biomass Fb were supplied to the combustion space 3 via a common fuel port 40, but this disclosure is not limited to this form. In some embodiments, although not shown, the furnace wall 18 of the furnace 2 has a first fuel port for supplying metallic magnesium Fa to the combustion space 3, and a second fuel port separate from the first fuel port for supplying biomass Fb to the combustion space 3. In this case, the metallic magnesium supply pipe 32 connects the Mg hopper 44 (discharge port of the Mg hopper 44) and the furnace 2 (first fuel port).

[0034] In the first embodiment, metallic magnesium Fa was introduced from the second inlet 42, but this disclosure is not limited to this form. In some embodiments, the first inlet 34 is configured to allow the introduction of metallic magnesium Fa along with biomass Fb. The particle size of the granular metallic magnesium Fa introduced into the first inlet 34 is larger than the particle size of the granular metallic magnesium Fa introduced into the second inlet 42. For example, although not shown, boiler 1 further includes a sieve with a mesh size of 2 mm or more, and an Mg input device that conveys the non-passing material (large-particle metallic magnesium Fa) that has been sieved out of the metallic magnesium Fa and puts it into hopper 36. As the particle size of metallic magnesium Fa increases, the reaction with the moisture contained in biomass Fb slows down, reducing its ignition properties. For this reason, large-particle metallic magnesium Fa can be pre-mixed with biomass Fb before introduction.

[0035] Metallic magnesium Fa generates hydrogen when it reacts with water and burns. In particular, since biomass Fb contains a large amount of water, when metallic magnesium Fa is burned together with biomass Fb, there is a risk that hydrogen will accumulate in the upper space 7. According to the first embodiment, since the boiler 1 further includes a hydrogen combustion device 52 located in the upper space 7, the hydrogen generated by the combustion of metallic magnesium Fa can be burned without accumulating in large quantities in the upper space 7 for a long time, and the hydrogen concentration can be reduced.

[0036] According to the first embodiment, the boiler 1 further includes a hydrogen concentration acquisition device 54 located in the upper space 7. By monitoring the concentration of hydrogen accumulating in the upper space 7, it is possible to prevent unintended malfunctions caused by hydrogen.

[0037] According to the first embodiment, when the hydrogen concentration 55 acquired by the hydrogen concentration acquisition device 54 exceeds the set concentration, the hydrogen combustion device 52 is activated. As a result, the hydrogen in the upper space 7 is burned, reducing the hydrogen concentration to below the set concentration and preventing unintended malfunctions caused by hydrogen.

[0038] In the first embodiment, the hydrogen combustion device 52 was driven when a drive signal 51 was transmitted from the control device 50, but the disclosure is not limited to this form. In some embodiments, the hydrogen combustion device 52 continues to drive while the boiler 1 is operating. In some embodiments, the hydrogen combustion device 52 continues to drive while the fuel feeder 4 is feeding metallic magnesium Fa into the furnace 2. In both of these cases, transmission of a drive signal 51 by the control device 50 is not required.

[0039] In the first embodiment, the hydrogen combustion device 52 was described as a burner, but this disclosure is not limited to this form. In some embodiments, the hydrogen combustion device 52 is a spark plug. By discharging a spark from the spark plug, the hydrogen in the upper space 7 is ignited and combusted, reducing the hydrogen concentration. In some embodiments, the hydrogen combustion device 52 is a catalytic combustion device configured to allow the combustion gas G rising in the furnace 2 to pass through, burning any hydrogen remaining in the combustion gas G as it passes through. In some embodiments, the hydrogen combustion device 52 is a ceramic body containing ceramic. By placing the ceramic body in the upper space 7, the temperature of the ceramic body rises due to the combustion gas G, making the ceramic body ready for hydrogen combustion. In this case, transmission of a drive signal 51 by the control device 50 is unnecessary.

[0040] According to the first embodiment, when the hydrogen concentration 55 acquired by the hydrogen concentration acquisition device 54 exceeds the set concentration, both the first on-off valve 35 and the second on-off valve 43 are closed. As a result, the supply of both metallic magnesium Fa and biomass Fb to the combustion space 3 is stopped, and the amount of hydrogen generated by the combustion of metallic magnesium Fa and biomass Fb can be reduced. Therefore, the rise in hydrogen concentration in the upper space 7 is suppressed, and the occurrence of unintended malfunctions due to hydrogen can be prevented.

[0041] In the first embodiment, the supply of both metallic magnesium Fa and biomass Fb to the combustion space 3 was stopped, but this disclosure is not limited to this embodiment. The supply of either metallic magnesium Fa or biomass Fb may be stopped.

[0042] In the first embodiment, the fuel supply stop device 59 included a first on / off valve 35 and a second on / off valve 43, but the disclosure is not limited to this form. For example, the fuel supply stop device 59 may include a crane that transports biomass Fb to the fuel input device 4, and the supply of biomass Fb may be stopped by stopping this crane. For example, the fuel supply stop device 59 may include a valve provided in the metallic magnesium supply pipe 32, and the supply of metallic magnesium Fa may be stopped by closing this valve.

[0043] In the first embodiment, when the hydrogen concentration 55 acquired by the hydrogen concentration acquisition device 54 exceeded the set concentration, the control device 50 drove the hydrogen combustion device 52 and closed both the first on-off valve 35 and the second on-off valve 43. However, this disclosure is not limited to this embodiment. When the hydrogen concentration acquired by the hydrogen concentration acquisition device 54 exceeds the set concentration, an operator may drive the hydrogen combustion device 52, or an operator may close both the first on-off valve 35 and the second on-off valve 43.

[0044] <Second Embodiment> A boiler 1 according to a second embodiment of this disclosure will now be described. The second embodiment differs from the first embodiment in that the boiler 1 further comprises a fire detection device 72 and a dry sand supply device 74. In the second embodiment, components that are the same as those in the first embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0045] (composition) Figure 3 is a schematic diagram showing the configuration of a plant 100 equipped with a boiler 1 according to the second embodiment. As illustrated in Figure 3, the boiler 1 further includes a fire detection device 72, a dry sand supply device 74, and

[0046] The ignition detection device 72 detects ignition in the metallic magnesium storage tank 70. The ignition detection device 72 may detect ignition based on, for example, the temperature inside the metallic magnesium storage tank 70, or based on the presence or absence of flames inside the metallic magnesium storage tank 70. The ignition detection device 72 is electrically connected to the control device 50 (p1), and when it detects ignition, it sends an ignition signal 73 to the control device 50.

[0047] The dry sand supply device 74 is configured to supply fluidized sand B stored in the fluidized sand storage tank 10 into the metallic magnesium storage tank 70 when the ignition detection device 72 detects ignition in the metallic magnesium storage tank 70. Specifically, as illustrated in Figure 3, the dry sand supply device 74 includes a fire extinguishing line 76 connecting the fluidized sand storage tank 10 and the metallic magnesium storage tank 70, and a fire extinguishing valve 78 provided in the fire extinguishing line 76. The fire extinguishing valve 78 is electrically connected to the control device 50 (p2). When the ignition detection device 72 transmits an ignition signal 73, the control device 50 transmits an instruction 75 to the fire extinguishing valve 78 to open, causing the fire extinguishing valve 78 to open. When the fire extinguishing valve 78 opens, the fluidized sand B stored in the fluidized sand storage tank 10 flows into the fire extinguishing line 76. The fluidized sand B flows through the fire extinguishing line 76 toward the metallic magnesium storage tank 70 and is supplied into the metallic magnesium storage tank 70.

[0048] (Effects / Actions) The operation and effects of the boiler 1 according to the second embodiment will now be described. According to the second embodiment, even if ignition occurs in the metallic magnesium storage tank 70, the metallic magnesium Fa that has ignited in the metallic magnesium storage tank 70 can be covered with fluidized sand B to cut off oxygen and quickly extinguish the fire by suffocation. In addition, the fluidized sand B can cover the metallic magnesium Fa that has not burned, suppressing ignition of this metallic magnesium Fa. Furthermore, according to the second embodiment, by using fluidized sand B for fire extinguishing, there is no need to prepare other sand for fire extinguishing separately from the fluidized sand B. As a result, the operating costs of the plant 100 can be reduced.

[0049] In the second embodiment, fluidized sand B was used for fire extinguishing, but the disclosure is not limited to this form. In some embodiments, though not shown, the plant 100 further includes a dry sand storage tank for storing dry sand separately from the fluidized sand B, and the dry sand supply device 74 supplies the dry sand stored in the dry sand storage tank to the metallic magnesium storage tank 70 when the ignition detection device 72 detects ignition in the metallic magnesium storage tank 70.

[0050] The contents described in each of the above embodiments can be understood, for example, as follows:

[0051] [1] The boiler (1) relating to this disclosure is Fireplace (2), The furnace is equipped with a fuel feeding device (4) for feeding metallic magnesium (Fa) as fuel.

[0052] Metallic magnesium does not produce carbon dioxide when burned (2Mg + O2 → 2MgO). Furthermore, because metallic magnesium is a solid at room temperature, it can reduce the fuel storage capacity compared to hydrogen or ammonia, which are gases at room temperature. According to the configuration described in [1] above, since metallic magnesium is used as fuel in the furnace, both carbon dioxide emissions and the need for large fuel storage capacity can be suppressed.

[0053] [2] In some embodiments, in the configuration described in [1] above, The aforementioned fuel further contains biomass (Fb).

[0054] Metallic magnesium has the property of burning when it reacts with water (Mg + H2O → MgO + H2). According to the configuration described in [2] above, metallic magnesium reacts with the water contained in the biomass and burns, promoting combustion in the furnace. In particular, biomass often has a high water content, making it difficult to use as fuel on its own. However, since biomass is fed in together with metallic magnesium as fuel, the metallic magnesium actively removes water from the biomass and burns. Therefore, high combustibility can be ensured regardless of the water content of the biomass. In other words, the range of effective utilization of biomass resources can be expanded.

[0055] [3] In some embodiments, in the configuration described in [2] above, The fuel supply device is A biomass supply pipe for supplying the biomass to the furnace, comprising a biomass supply pipe (30) connecting a first inlet (34) into which the biomass is fed and the furnace, A metallic magnesium supply pipe for supplying the metallic magnesium to the furnace, comprising a metallic magnesium supply pipe (32) connecting a second inlet (42) into which the metallic magnesium is introduced and the biomass supply pipe.

[0056] When using metallic magnesium and biomass as fuel, it is preferable to provide separate input ports for metallic magnesium and biomass to prevent combustion of the metallic magnesium and biomass before input. According to the configuration described in [3] above, metallic magnesium is introduced from a second input port separate from the first input port into which biomass is introduced. This prevents the burning of metallic magnesium and biomass before input.

[0057] [4] In some embodiments, in the configuration described in [3] above, The first input port is configured to allow the input of metallic magnesium along with the biomass. The particle size of the granular metallic magnesium introduced into the first inlet is larger than the particle size of the granular metallic magnesium introduced into the second inlet.

[0058] As the particle size of metallic magnesium increases, the reaction with moisture contained in the biomass slows down, reducing its ignition properties. According to the configuration described in [4] above, metallic magnesium can be pre-mixed with the biomass before it is added.

[0059] [5] In some embodiments, in the configuration described in any one of [1] to [4] above, The furnace has a fluidized bed (6) formed inside.

[0060] Because metallic magnesium has a low specific gravity, it can be easily fluidized by the combustion air blown into the furnace. According to the configuration described in [5] above, metallic magnesium can be used as fuel in a fluidized boiler in which a fluidized bed is formed in the furnace.

[0061] [6] In some embodiments, in the configuration described in any one of [1] to [5] above, The aforementioned metallic magnesium is in the form of granules with a diameter of 2 mm or more.

[0062] According to the configuration described in [6] above, it is possible to prevent the ignition of metallic magnesium before it is added.

[0063] [7] In some embodiments, in the configuration described in [5] above, The furnace further comprises a hydrogen combustion device (52) positioned above the fluidized bed in the furnace for burning hydrogen that has accumulated in the upper part of the furnace.

[0064] According to the configuration described in [7] above, the hydrogen generated by the combustion of metallic magnesium can be burned at the top of the furnace, thereby reducing the hydrogen concentration.

[0065] [8] In some embodiments, in the configuration described in [5] or [7] above, The system further includes a hydrogen concentration acquisition device (54) positioned above the fluidized bed in the furnace, which acquires the concentration of hydrogen accumulating in the upper part of the furnace.

[0066] According to the configuration described in [8] above, by monitoring the concentration of hydrogen accumulating in the upper part of the furnace, it is possible to prevent unintended malfunctions caused by hydrogen.

[0067] [9] In some embodiments, in the configuration described in [8] above, The system further includes a fuel supply stop device (59) configured to stop supplying the fuel to the furnace when the hydrogen concentration obtained by the hydrogen concentration acquisition device exceeds a preset concentration.

[0068] According to the configuration described in [9] above, when the hydrogen concentration exceeds a set concentration, the fuel supply is stopped, and the rise in hydrogen concentration is suppressed, thereby preventing unintended malfunctions caused by hydrogen.

[0069]

[10] In some embodiments, in the configuration described in [5] above, A hydrogen combustion device is positioned above the fluidized bed in the furnace and is used to burn hydrogen that accumulates in the upper part of the furnace. The furnace is further equipped with a hydrogen concentration acquisition device, which is positioned above the fluidized bed in the furnace and acquires the concentration of hydrogen accumulating in the upper part of the furnace. The hydrogen combustion device is configured to activate when the hydrogen concentration obtained by the hydrogen concentration acquisition device exceeds a preset concentration.

[0070] According to the configuration described in

[10] above, if the hydrogen concentration exceeds the set concentration, the hydrogen concentration is reduced, thereby preventing unintended malfunctions caused by hydrogen.

[0071]

[11] In some embodiments, in the configuration described in any one of [1] to

[10] above, A metallic magnesium storage tank (70) for storing the metallic magnesium, A fire detection device (72) for detecting ignition in the aforementioned magnesium metal storage tank, The system further includes a dry sand supply device (74) configured to supply dry sand (B) into the metallic magnesium storage tank when the ignition detection device detects an ignition in the metallic magnesium storage tank.

[0072] According to the configuration described in

[11] above, metallic magnesium can be quickly extinguished by dry sand. In addition, the dry sand can suppress the ignition of unburned metallic magnesium.

[0073]

[12] In some embodiments, in the configuration described in

[11] above, The aforementioned furnace has a fluidized bed formed inside, The system further includes a fluidized sand storage tank (10) for storing the fluidized sand (B) supplied to the fluidized bed, The dry sand supply device is configured to supply the fluidized sand stored in the fluidized sand storage tank as dry sand into the metallic magnesium storage tank.

[0074] According to the configuration described in

[12] above, by using fluidized sand as dry sand, it becomes unnecessary to prepare dry sand separately from the fluidized sand. This reduces the operating costs of the plant.

[0075]

[13] The plant (100) relating to this disclosure is A boiler described in any one of the above [1] to

[12] , A steam turbine that rotates using steam generated by the aforementioned boiler, The system includes a generator that generates electricity by the rotation of the aforementioned steam turbine.

[0076] The configuration described in

[13] above provides a plant with a boiler that suppresses both carbon dioxide emissions and the enlargement of fuel storage capacity. [Explanation of symbols]

[0077] 1 Boiler 2 Furnace 4 Fuel injection device 6. Fluidized bed 10 Fluidized sand storage tank 30 Biomass supply pipes 32. Metallic magnesium supply pipe 34 1st input port 42 2nd input port 50 Control device 52 Hydrogen combustion device 54 Hydrogen concentration acquisition device 59 Fuel supply stop device 70. Metallic Magnesium Storage Tank 72. Fire detection device 74 Dry sand supply device 100 plants B Fluid sand Fa Metallic Magnesium Fb Biomass

Claims

1. A furnace; The furnace is equipped with a fuel feeding device for feeding metallic magnesium as fuel, A metallic magnesium storage tank for storing the aforementioned metallic magnesium, A fire detection device for detecting ignition in the aforementioned magnesium metal storage tank, The system further comprises a dry sand supply device configured to supply dry sand into the metallic magnesium storage tank when the ignition detection device detects an ignition in the metallic magnesium storage tank, The aforementioned furnace has a fluidized bed formed inside, The system further comprises a fluidized sand storage tank for storing the fluidized sand supplied to the fluidized bed, The dry sand supply device is configured to supply the fluidized sand stored in the fluidized sand storage tank as dry sand into the metallic magnesium storage tank. Boiler.

2. A furnace; The furnace is equipped with a fuel feeding device for feeding metallic magnesium as fuel, The aforementioned furnace has a fluidized bed formed inside, The system further comprises a hydrogen concentration acquisition device positioned above the fluidized bed in the furnace and for acquiring the concentration of hydrogen accumulating in the upper part of the furnace. Boiler.

3. The system further includes a fuel supply stop device configured to stop supplying fuel to the furnace when the hydrogen concentration obtained by the hydrogen concentration acquisition device exceeds a preset concentration. The boiler according to claim 2.

4. A furnace; The furnace is equipped with a fuel feeding device for feeding metallic magnesium as fuel, The aforementioned furnace has a fluidized bed formed inside, The system further comprises a hydrogen combustion device positioned above the fluidized bed in the furnace for burning hydrogen accumulated in the upper part of the furnace. Boiler.

5. The furnace is further equipped with a hydrogen concentration acquisition device positioned above the fluidized bed in the furnace, which acquires the concentration of hydrogen accumulating in the upper part of the furnace. The hydrogen combustion device is configured to activate when the hydrogen concentration obtained by the hydrogen concentration acquisition device exceeds a preset concentration. The boiler according to claim 4.

6. A furnace; The furnace is equipped with a fuel feeding device for feeding metallic magnesium as fuel, The aforementioned fuel further contains biomass, The fuel supply device is A biomass supply pipe for supplying the biomass to the furnace, comprising a biomass supply pipe connecting a first inlet into which the biomass is fed and the furnace, A metallic magnesium supply pipe for supplying the metallic magnesium to the furnace, comprising a metallic magnesium supply pipe connecting a second inlet into which the metallic magnesium is introduced and the biomass supply pipe, The first input port is configured to allow the input of metallic magnesium along with the biomass. The particle size of the granular metallic magnesium introduced into the first inlet is larger than the particle size of the granular metallic magnesium introduced into the second inlet. Boiler.

7. The aforementioned furnace has a fluidized bed formed inside. The boiler according to claim 6.

8. The aforementioned metallic magnesium is in the form of granules with a diameter of 2 mm or more. A boiler according to any one of claims 1 to 7.

9. A boiler according to any one of claims 1 to 7, A steam turbine that rotates using steam generated by the aforementioned boiler, The system comprises a generator that generates electricity by the rotation of the aforementioned steam turbine, plant.

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