Combustion device

Abstract

To provide a combustion device capable of suppressing generation of nitrogen oxides (NOx) during combustion of fuel that contains ammonia (NH3).SOLUTION: The combustion apparatus 1 includes a combustion section 2 having a combustion chamber 21 for burning fuel containing ammonia, a first regenerator 3 and a second regenerator 4 which communicate with the combustion chamber 21 and are provided with a heat storage body 7 and which alternately repeat heat storage from exhaust gas after combustion to the heat storage body 7 and heat dissipation from the heat storage body 7 storing heat to a first oxygen source for burning fuel, a first oxygen source supply section 5 which supplies the first oxygen source to the combustion chamber 21, and a second oxygen source supply section 6 which supplies a second oxygen source to the combustion chamber 21 at least after switching of a flow destination of the first oxygen source by the first oxygen supply section 5.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This application relates to combustion devices. [Background technology]

[0002] Combustion devices heat raw materials by burning fuel with air. For example, Patent Document 1 discloses a fuel containing ammonia (NH3). For example, Patent Document 2 discloses a combustion device that includes a temperature-raising zone equipped with a heating burner and two heat-storage zones provided on the left and right of the temperature-raising zone.

[0003] In the combustion device disclosed in Patent Document 2, gas passing through the left heat storage zone is first preheated by the heat stored in the heat storage zone and then moves to the temperature increase zone. In the temperature increase zone, the gas is heated by the combustion of combustion gas injected from a heating burner. The gas then passes through the right heat storage zone, exchanging heat with the heat storage zone. When the preheating effect of the left heat storage zone decreases, the gas flow is switched so that it passes through the right heat storage zone, the temperature increase zone, and the left heat storage zone in that order. In this way, high heat recovery efficiency is achieved by alternately dissipating heat from the heat storage zone to the gas before treatment and storing heat from the treated gas in the heat storage zone in the left and right heat storage zones.

[0004] In the combustion device described above, the combustion of the combustion gas is stopped when the gas flow is switched. When the combustion is stopped, the temperature of the heating zone drops, so immediately after the gas flow is switched, the fuel is burned when the temperature of the heating zone is low. When the fuel is ammonia, burning the ammonia when the temperature of the heating zone is low easily generates nitrogen oxides (NOx), as described below.

[0005] The relationship between the NOx concentration in the exhaust gas and the exhaust gas temperature (temperature of the heating zone) will be explained with reference to Fig. 10 and Fig. 11. Fig. 10 is a graph showing the relationship between the NOx concentration in the exhaust gas and the exhaust gas temperature when city gas is burned. Fig. 11 is a graph showing the relationship between the NOx concentration in the exhaust gas and the exhaust gas temperature when ammonia is burned. In Fig. 10 and Fig. 11, the solid line indicates the NOx concentration, and the dashed line indicates the exhaust gas temperature.

[0006] As shown in Figure 10, when city gas is burned when the temperature of the exhaust gas (heating zone) is low, the NOx concentration in the exhaust gas is low. On the other hand, as shown in Figure 11, when ammonia is burned, the NOx concentration in the exhaust gas temporarily increases while the temperature of the exhaust gas is rising (for example, after 500 minutes have passed). In this way, when ammonia is burned when the temperature of the heating zone is low, the NOx concentration in the exhaust gas increases (NOx is more likely to be generated). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2014-528052 [Patent Document 2] Japanese Patent Application Publication No. 54-128171 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide a combustion device that can suppress the generation of nitrogen oxides (NOx) when burning fuel containing ammonia (NH3). [Means for solving the problem]

[0009] The combustion device includes a combustion section having a combustion chamber for burning a fuel containing ammonia, a first heat storage chamber and a second heat storage chamber that are connected to the combustion chamber and are provided with a heat storage body, and that alternately store heat from exhaust gas after combustion in the heat storage body and release heat from the heat storage body to a first oxygen source that burns the fuel, a first oxygen source supply section that alternately flows the first oxygen source through the first heat storage chamber and the second heat storage chamber and supplies the first oxygen source to the combustion chamber, and a second oxygen source supply section that supplies a second oxygen source to the combustion chamber at least after the first oxygen source supply section switches the flow destination of the first oxygen source. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of a combustion device according to the first embodiment [Figure 2] FIG. 3 is a cross-sectional view of the combustion device according to the embodiment. [Figure 3] FIG. 10 is an enlarged cross-sectional view of a burner in the same embodiment. [Figure 4] FIG. 10 is a diagram showing a nozzle tip surface of the burner in the embodiment. [Figure 5] Cross-sectional view of a combustion device according to a second embodiment [Figure 6] Cross-sectional view of a combustion device according to a third embodiment [Figure 7] Cross-sectional view of a combustion device according to a fourth embodiment [Figure 8] FIG. 10 is a diagram showing a modified example of the nozzle tip surface of the burner. [Figure 9] FIG. 10 is an enlarged cross-sectional view showing a modified example of the burner. [Figure 10] A graph showing the relationship between NOx concentration in exhaust gas and exhaust gas temperature when burning city gas. [Figure 11] Graph showing the relationship between NOx concentration in exhaust gas and exhaust gas temperature when ammonia is burned DETAILED DESCRIPTION OF THE INVENTION

[0011] In each drawing, the dimensions of the components may be enlarged or reduced relative to their actual dimensions, for example, to facilitate understanding. Also, in each drawing, for example, to facilitate understanding, some of the components may be omitted.

[0012] Terms including ordinal numbers such as "first" and "second" are used to describe various components, but these terms are used only to distinguish one component from another, and the components are not particularly limited by these terms. The number of components including ordinal numbers is not particularly limited, and may be, for example, one. Furthermore, the ordinal numbers used in the following specification may differ from the ordinal numbers described in the claims.

[0013] [First embodiment] A first embodiment of a combustion device will be described below with reference to Figures 1 to 4. Note that the following embodiment (and the other embodiments as well) is provided as an example to aid in understanding the configuration of the combustion device, and is not intended to limit the configuration of the combustion device. Figure 1 is a schematic diagram of a combustion device 1 according to the first embodiment.

[0014] As shown in Fig. 1, the combustion device 1 includes a combustion section 2 having a combustion chamber 21 for burning fuel, a first heat storage chamber 3 and a second heat storage chamber 4 provided with a heat storage body 7 that stores heat of exhaust gas after combustion, a first oxygen source supply section 5 that supplies a first oxygen source to the combustion section 2, and a second oxygen source supply section 6 that supplies a second oxygen source to the combustion chamber 21. Fig. 1 shows an example of a side-port type combustion device 1 in which the first heat storage chamber 3 and the second heat storage chamber 4 are arranged opposite each other with the combustion chamber 21 in between, but the combustion device may also be an end-port type combustion device in which the first heat storage chamber 3 and the second heat storage chamber 4 are adjacent to each other.

[0015] The combustion device 1 preferably includes an exhaust section 8 that exhausts exhaust gas from the combustion chamber 21, a temperature measurement section 9 that measures the temperature of the combustion section 2, a fuel supply section 10 that supplies fuel to the combustion section 2, and a raw material supply section 11 that supplies raw material to the combustion section 2.

[0016] The discharge section 8 may include, for example, a reaction tower 81 that treats the exhaust gas generated by combustion in the combustion chamber 21, a dust collector 82 that removes dust from the exhaust gas treated in the reaction tower 81, a chimney 83 that discharges the exhaust gas from which the dust has been removed by the dust collector 82 to the outside of the combustion device 1, a first exhaust gas flow path 84 that connects the first heat storage chamber 3 and the second heat storage chamber 4 to the reaction tower 81, a second exhaust gas flow path 85 that connects the reaction tower 81 and the dust collector 82, and a third exhaust gas flow path 86 that connects the dust collector 82 to the chimney 83.

[0017] The reaction tower 81 may, for example, remove specific substances from the exhaust gas. Although not particularly limited, the reaction tower 81 may, for example, remove nitrogen oxides and sulfur oxides by spraying ozone or NaOH toward the exhaust gas. Note that the discharge section 8 may not, for example, be equipped with the reaction tower 81 and the dust collector 82, and the exhaust gas from the combustion section 2 may be directly discharged from the chimney 83 to the outside of the combustion device 1 without being treated.

[0018] The configuration of the temperature measurement unit 9 is not particularly limited, and may be any configuration capable of measuring high temperatures (e.g., 1000°C or higher). The temperature measurement unit 9 may measure the temperature of the combustion chamber 21 (e.g., the ceiling) or the heat storage chambers 3 and 4, or may measure the temperature of the exhaust gas.

[0019] The fuel supply unit 10 may include a fuel adjustment unit (not shown) that adjusts the amount of fuel supplied to the combustion chamber 21. The fuel may be any material (for example, liquid or gas) that contains ammonia (NH3) and generates heat when oxidized (combusted). The fuel is preferably a gas. This is because if the fuel is liquid, it may take heat from the combustion unit when vaporized, causing a drop in the temperature of the combustion chamber 21. Note that the fuel is not limited to the above and may also be liquid.

[0020] The fuel may be, for example, fuel ammonia, or both fuel ammonia and fossil fuel (heavy oil, city gas, LP gas (propane gas), etc.). Although not particularly limited, the fuel adjusting unit may be a flow rate adjusting valve. The fuel supplied to the combustion chamber 21 spontaneously ignites depending on the temperature and oxygen concentration of the combustion chamber 21.

[0021] Although not shown, the raw material supply unit 11 may include, for example, a raw material supply port connected to the combustion chamber 21 and a raw material adjustment unit that adjusts the amount of raw material supplied to the combustion unit 2. The raw material supply unit 11 may continuously supply raw material to the combustion chamber 21 during combustion, for example, or may supply a set amount of raw material to the combustion chamber 21 at once for one combustion and stop supplying raw material to the combustion chamber 21 until the combustion is completed. For example, a portion of the raw material may be burned (oxidized) as fuel.

[0022] Fig. 2 is a cross-sectional view of the combustion device 1 according to the first embodiment. As shown in Fig. 2, the combustion section 2 includes a combustion chamber 21 to which raw material, fuel, a first oxygen source, and a second oxygen source are supplied, and a burner 22 provided in the combustion chamber 21. The combustion chamber 21 may be made of, for example, bricks.

[0023] The burner 22 is connected to the fuel supply unit 10. The burner 22 may be configured, for example, to be able to change the angle or length of the combustion flame. For example, the wider the angle of the combustion flame of the burner 22, the more oxygen sources are involved in the combustion, and the narrower the angle of the combustion flame of the burner 22, the fewer oxygen sources are involved in the combustion. Also, for example, the longer the length of the combustion flame of the burner 22, the more oxygen sources are involved in the combustion, and the shorter the length of the combustion flame of the burner 22, the fewer oxygen sources are involved in the combustion. A plurality of burners 22 may be provided in a direction perpendicular to FIG. 1. The burner 22 may, for example, be equipped with an ignition unit that ignites the fuel.

[0024] In this embodiment, the burner 22 is configured as an under-port type that is provided below the communication part 23 between the combustion chamber 21 and the heat regenerators 3 and 4, but is not limited to this. For example, the burner 22 may be configured as a through-port type that is provided in the communication part 23 and can descend below the communication part 23 when not in combustion. The detailed configuration of the burner 22 will be described later.

[0025] The first heat storage chamber 3 and the second heat storage chamber 4 are each connected to the combustion chamber 21 (connection section 23). The first heat storage chamber 3 and the second heat storage chamber 4 are, for example, provided opposite each other with the combustion section 2 in between. It is preferable that the first heat storage chamber 3 and the second heat storage chamber 4 have the same volume. The first heat storage chamber 3 and the second heat storage chamber 4 may be made of, for example, bricks.

[0026] The heat storage body 7 is provided in each of the first heat storage chamber 3 and the second heat storage chamber 4. The heat storage body 7 is made up of a plurality of heat storage materials that have sufficient heat exchange capacity under the operating temperature conditions. The heat resistance temperature of the heat storage material may be lower (for example, 1200°C) than the heat resistance temperature of the combustion chamber 21 (for example, 1600°C). The heat storage material is preferably ceramics (which may contain magnesium, chromium, etc.) that have excellent heat resistance. The heat storage body 7 may be, for example, sand or metal. The heat storage material is formed in a shape that allows gas or liquid to flow through it. The heat storage material is formed in the shape of, for example, a brick with holes or a honeycomb.

[0027] The first oxygen source supply unit 5 supplies the first oxygen source to the combustion chamber 21 via the first heat storage chamber 3 or the second heat storage chamber 4. The first oxygen source is a liquid or gas containing at least oxygen (O). The first oxygen source is preferably a gas. The first oxygen source is, for example, air or oxygen-enriched air.

[0028] The first oxygen source supply unit 5 includes a first communication passage 51 (also referred to as the "first supply path 51") that communicates with the first heat storage chamber 3, a second communication passage 52 (also referred to as the "second supply path 52") that communicates with the second heat storage chamber 4, and a switching unit 53 that can switch the flow of the first oxygen source to each of the communication passages 51, 52.

[0029] The switching unit 53 has a structure that can open and close each of the communication passages 51, 52. The switching unit 53 includes, for example, a damper-type switching valve 531. In this embodiment, the switching unit 53 includes a circular switching passage 532 that communicates with each of the communication passages 51, 52, and the switching valve 531 is provided within the switching passage 532. This allows the single switching valve 531 to switch the flow of the first oxygen source to each of the communication passages 51, 52. Note that the switching unit 53 is not limited to the above configuration. For example, the switching valve 531 may be provided in each of the communication passages 51, 52. In FIG. 2, the dashed lines indicate a state in which the switching valve 531 is switched between open and closed.

[0030] The first oxygen source supply unit 5 includes a supply port 54 and a first oxygen source supplier 55 for supplying the first oxygen source from the supply port 54. In the present embodiment, the supply port 54 is provided in the switching path 532, but this is not limiting. For example, the supply port 54 may be provided in each of the communication paths 51 and 52. That is, a plurality of supply ports 54 may be provided.

[0031] In this embodiment, the first exhaust gas passage 84 is connected to the switching passage 532, but is not limited to this. For example, the first exhaust gas passage 84 may be directly connected to each of the heat storage chambers 3, 4.

[0032] The first oxygen source supply device 55 may have any configuration as long as it is capable of supplying the first oxygen source. In this embodiment, the first oxygen source supply device 55 is a blower, but is not limited to this. When the first oxygen source is a gas, the first oxygen source supply device 55 may be, for example, an exhaust fan. When the first oxygen source is a liquid, the first oxygen source supply device 55 may be, for example, a liquid pump. Note that when the first oxygen source supply device 55 is an exhaust fan, the exhaust fan may be disposed in the discharge section 8, for example.

[0033] The first oxygen source supply unit 5 preferably includes a switching control unit (not shown) that controls the switching valve 531. The switching control unit switches the switching valve 531 between open and closed when a predetermined condition is met. The predetermined condition is, for example, a predetermined time or a temperature measured by the temperature measurement unit 9. When the predetermined condition is the measured temperature, the switching control unit switches the switching valve 531 between open and closed when the temperature measured by the temperature measurement unit 9 becomes equal to or higher than a set temperature.

[0034] As shown by the solid arrows in FIG. 2 , when the switching valve 531 of the first communication passage 51 is opened (the switching valve 531 of the second communication passage 52 is closed), the first oxygen source is supplied from the supply port 54 and flows through the first communication passage 51 and the first heat storage chamber 3 in this order. When the first oxygen source flows through the first heat storage chamber 3, it is warmed by the heat stored in the heat storage body 7. That is, the heat storage body 7 provided in the first heat storage chamber 3 releases heat to the first oxygen source flowing through the first heat storage chamber 3. The first oxygen source is then supplied to the combustion chamber 21, where fuel is combusted by the first oxygen source and the second oxygen source, generating exhaust gas. The exhaust gas flows through the second heat storage chamber 4 and the second communication passage 52 in this order, and is discharged to the outside of the combustion device 1 through the first exhaust gas flow path 84. When the exhaust gas flows through the second heat storage chamber 4, it dissipates heat to the heat storage body 7. That is, the heat storage body 7 provided in the second heat storage chamber 4 stores heat by the exhaust gas that flows through the second heat storage chamber 4. In this embodiment, the second communication passage 52 is also used as an exhaust gas flow path.

[0035] Next, the switching valve 531 is switched between open and closed states under predetermined conditions, and the switching valve 531 of the second communication passage 52 is opened (the switching valve 531 of the first communication passage 51 is closed). Then, as shown by the dashed arrow in FIG. 2 , the first oxygen source is supplied from the supply port 54 and flows through the second communication passage 52 and the second heat storage chamber 4 in that order. When the first oxygen source flows through the second heat storage chamber 4, it is warmed by the heat stored in the heat storage body 7. That is, the heat storage body 7 provided in the second heat storage chamber 4 releases heat to the first oxygen source flowing through the second heat storage chamber 4. The first oxygen source is then supplied to the combustion chamber 21, and fuel is combusted by the first oxygen source and the second oxygen source, generating exhaust gas. The exhaust gas flows through the first heat storage chamber 3 and the first communication passage 51 in that order, and is discharged to the outside of the combustion device 1 through the first exhaust gas flow path 84. When the exhaust gas flows through the first heat storage chamber 3, it dissipates heat to the heat storage body 7. That is, the heat storage body 7 provided in the first heat storage chamber 3 stores heat by the exhaust gas that flows through the first heat storage chamber 3. In this embodiment, the first communication passage 51 is also used as an exhaust gas flow path.

[0036] As described above, the first heat storage chamber 3 and the second heat storage chamber 4 alternately store heat from the exhaust gas after combustion in the heat storage body 7 and release heat from the stored heat storage body 7 to the first oxygen source. The first oxygen source supply unit 5 alternately flows the first oxygen source through the first heat storage chamber 3 and the second heat storage chamber 4, and supplies the first oxygen source to the combustion chamber 21. When switching the flow destination of the first oxygen source (first heat storage chamber 3 or second heat storage chamber 4), it is preferable to stop combustion (fuel supply) in the combustion chamber 21. This is because if combustion is started during switching, there is a risk of a shortage of the first oxygen source, which could result in the generation of unburned ammonia, etc.

[0037] The second oxygen source supply unit 6 supplies the second oxygen source to the combustion chamber 21 at least after the first oxygen source supply unit 5 switches the flow destination of the first oxygen source (to the first heat storage chamber 3 or the second heat storage chamber 4). According to this configuration, after the flow destination of the first oxygen source is switched and the temperature of the combustion chamber 21 decreases, the second oxygen source having a higher oxygen concentration than the first oxygen source is supplied to the combustion chamber 21, thereby increasing the oxygen concentration in the combustion chamber 21 and accelerating the combustion of the ammonia-containing fuel. This accelerates the temperature rise of the combustion chamber 21, shortens the time it takes for the temperature of the combustion chamber 21 to decrease, and suppresses the generation of nitrogen oxides (NOx). The second oxygen source supply unit 6 may supply the second oxygen source to the combustion chamber 21 before (or simultaneously with) the first oxygen source supply unit 5 switches the flow destination of the first oxygen source.

[0038] The second oxygen source is preferably a liquid or gas having a higher oxygen concentration than the first oxygen source. The second oxygen source is more preferably a gas. The second oxygen source is, for example, an oxidizing agent such as pure oxygen or oxygen-enriched air obtained by enriching air with oxygen. However, the second oxygen source is not limited to the above and may also be an oxidizing agent such as air.

[0039] The second oxygen source supply unit 6 includes a second oxygen source supplier (not shown) for supplying the second oxygen source. The second oxygen source supplier may be configured to supply the second oxygen source. In this embodiment, the second oxygen source supplier is a blower, but is not limited to this. When the second oxygen source is a liquid, the second oxygen source supplier may be a liquid pump or the like. The second oxygen source supply unit 6 may include a second oxygen source adjustment unit (not shown) that adjusts the amount of the second oxygen source supplied to the combustion chamber 21.

[0040] It is preferable that the second oxygen source supply unit 6 stops supplying the second oxygen source when the temperature measured by the temperature measurement unit 9 rises to a predetermined temperature. However, the second oxygen source supply unit 6 is not limited to this, and may constantly supply the second oxygen source to the combustion chamber 21.

[0041] In this embodiment, the second oxygen source supply unit 6 supplies the second oxygen source from the burner 22 to the combustion chamber 21. With this configuration, by supplying the second oxygen source from the burner 22, the second oxygen source can be supplied to the combustion chamber 21 from near the fuel injection port 223, which will be described later. This promotes the reaction between the fuel and the second oxygen source, i.e., combustion, reduces the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0042] However, the second oxygen source supply unit 6 is not limited to this, and may be configured to supply the second oxygen source toward the burner 22. That is, the second oxygen source supply unit 6 may supply the second oxygen source directly to the combustion chamber 21. The same applies to the fuel supply unit 10.

[0043] It is preferable that the second oxygen source supply unit 6 supplies the second oxygen source to the combustion chamber 21 before burning the fuel. With this configuration, the oxygen concentration in the combustion chamber 21 can be increased, making it easier to burn the fuel. This accelerates the temperature rise in the combustion chamber 21, shortens the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of nitrogen oxides (NOx).

[0044] The second oxygen source supply unit 6 preferably supplies the second oxygen source to the combustion chamber 21 before supplying the first oxygen source. This allows the fuel to be combusted with the second oxygen source (primary combustion) and then combusted with the first oxygen source (secondary combustion). The second oxygen source supply unit 6 preferably supplies the second oxygen source so that unburned ammonia is generated when the fuel is combusted. That is, it is preferable that there is a shortage of oxygen to combust the fuel in the primary combustion. This allows the NOx generated in the primary combustion to react with and decompose the unburned ammonia, and the unburned ammonia to be burned in the secondary combustion. As a result, the NOx contained in the exhaust gas can be suppressed, and the unburned ammonia contained in the exhaust gas can also be suppressed.

[0045] The second oxygen source is preferably mixed with the fuel before combustion. According to this configuration, mixing the second oxygen source with the fuel promotes the reaction between the fuel and the second oxygen source, i.e., combustion, and can hasten the temperature rise in the combustion chamber 21. This reduces the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx. Note that the second oxygen source supply unit 6 is not limited to the above, and the second oxygen source may be supplied to the combustion chamber 21 without being mixed with the fuel.

[0046] Fig. 3 is an enlarged cross-sectional view of burner 22. As shown in Fig. 3, burner 22 includes, for example, a nozzle 220, a fuel flow path 221 through which fuel flows, a second oxygen source flow path 222 through which a second oxygen source flows, a fuel injection port 223 through which fuel is injected (sprayed), and a second oxygen source injection port 224 through which the second oxygen source is injected (sprayed). In Fig. 3, solid arrows indicate the flow of the second oxygen source, and two-dot chain arrows indicate the flow of fuel.

[0047] The nozzle 220 is formed, for example, in a cylindrical shape, and is provided therein with a fuel passage 221 and a second oxygen source passage 222. The fuel passage 221 is connected to the fuel supply unit 10 (see FIG. 2). The fuel passage 221 is provided, for example, so as to pass through the center of the nozzle 220. The second oxygen source passage 222 is connected to the second oxygen source supply unit 6 (see FIG. 2). The second oxygen source passage 222 is provided, for example, around the fuel passage 221. Alternatively, the second oxygen source passage 222 may be provided so as to pass through the center of the nozzle 220, and the fuel passage 221 may be provided around the second oxygen source passage 222.

[0048] The fuel injection port 223 and the second oxygen source injection port 224 are provided, for example, on the tip surface 220a of the nozzle 220. The fuel injection port 223 communicates with the fuel flow path 221, and the second oxygen source injection port 224 communicates with the second oxygen source flow path 222.

[0049] FIG. 4 is a diagram showing the tip surface 220a of the nozzle 220. As shown in FIG. 4, the fuel injection port 223 is provided, for example, in the center of the tip surface 220a and is formed in a circular shape. The second oxygen source injection port 224 is formed, for example, in an annular shape so as to surround the fuel injection port 223. As a result, the fuel injected from the fuel injection port 223 is mixed with at least a part of the second oxygen source injected from the second oxygen source injection port 224, and then combusted. The width of the second oxygen source injection port 224 is, for example, smaller than the hole diameter of the fuel injection port 223. Note that the second oxygen source injection port 224 may be provided, for example, on a different surface from the fuel injection port 223.

[0050] The second oxygen source is preferably injected before ignition, and more preferably before the fuel, thereby increasing the oxygen concentration around the burner 22 and accelerating the combustion of the fuel.

[0051] 3 and 4, the burner 22 preferably includes a cooling unit 225 that cools the nozzle 220. This can prevent the nozzle 220 from burning in the high-temperature combustion chamber 21. The cooling unit 225 is preferably provided so as to cover the outer peripheral surface of the nozzle 220. The cooling unit 225 is preferably provided on the combustion chamber 21 side of the nozzle 220. The cooling unit 225 may have any configuration as long as it can cool the nozzle 220. The cooling unit 225 is, for example, a water-cooled cooling device through which cooling water flows.

[0052] As shown in FIG. 2, the first oxygen source supply unit 5 preferably includes an adjustment unit (not shown) (also referred to as a "first oxygen source adjustment unit") that adjusts the supply amount of the first oxygen source. The adjustment unit preferably adjusts (reduces) the supply amount of the first oxygen source according to the supply amount (of oxygen) of the second oxygen source. With this configuration, by adjusting the supply amount of the first oxygen source, the oxygen supply amounts from the first oxygen source and the second oxygen source can be made closer to the theoretical oxygen amount. This makes it possible to suppress an increase in fuel consumption. The theoretical oxygen amount is the amount of oxygen required for complete combustion of fuel.

[0053] The adjusting unit preferably adjusts the amount of oxygen supplied by the first oxygen source and the second oxygen source to the theoretical amount of oxygen, more preferably to 1.05 times the theoretical amount of oxygen. In this embodiment, the adjusting unit adjusts the amount of oxygen supplied by the first oxygen source by controlling the first oxygen source supplier 55 (for example, by controlling the rotation speed of the fan), but is not limited to this.

[0054] Next, the raw material, fuel, first oxygen source, and second oxygen source according to this embodiment will be described. Note that the raw material, fuel, first oxygen source, and second oxygen source are not limited to the following.

[0055] In this embodiment, the raw materials are raw materials for glass (for example, soda-lime glass). Specifically, the raw materials include, for example, cullet (crushed glass scraps), batch (SiO2, Na2CO3, CaCO3, Na2SO4, carbon (C)), and mixtures thereof. SiO2 is the main raw material for soda-lime glass, and Na2SO4 is an auxiliary raw material that functions as an oxidizing agent and a fining agent (defoaming agent).

[0056] Cullet is mainly made from crushed glass bottles, etc., and therefore contains not only glass chips but also organic matter such as resin film labels and paper labels. Carbon (e.g., powdered carbon) is used, for example, to color glass (e.g., brown).

[0057] The glass raw material may be heated to, for example, 1200° C. or higher, specifically 1450° C. or higher, or may be heated to, for example, 2000° C. or lower, specifically 1600° C. or lower, in order to be melted. Thus, in this embodiment, the combustion section 2 is a glass melting furnace.

[0058] In this embodiment, the first oxygen source is air. Since air, which is an oxygen source, contains nitrogen, it is also a nitrogen source that can generate nitrogen oxides through combustion. In this embodiment, the fuel is fuel ammonia. In this embodiment, the second oxygen source is an oxidizer such as pure oxygen or oxygen-enriched air. This accelerates the combustion of the fuel and the temperature rise of the combustion chamber 21.

[0059] The type of nitrogen oxides generated during combustion is also affected by the combustion temperature (the temperature at which the fuel oxidizes). For example, fuel NOx is more likely to be generated when the combustion temperature is low, while thermal NOx is more likely to be generated as the combustion temperature increases. Fuel NOx is NOx generated from the nitrogen contained in the fuel, and thermal NOx is NOx generated from nitrogen, which is an oxygen source. In Figure 11, most of the NOx generated when the exhaust gas temperature is around 1200°C is fuel NOx, while the NOx generated when the exhaust gas temperature is around 1400°C contains a large amount of thermal NOx.

[0060] [Second embodiment] Next, a second embodiment of the combustion device will be described with reference to Fig. 5. The second embodiment can be configured similarly to the first embodiment except for the configuration described below, so the commonalities will be omitted and differences will be mainly described. Components already described in the first embodiment will be assigned the same reference numerals and redundant description will be omitted. Fig. 5 is a cross-sectional view of the combustion device 1 according to the second embodiment.

[0061] 5, the combustion device 1 according to the second embodiment includes a third oxygen source supply unit 12 that supplies a third oxygen source having a higher oxygen concentration than the first oxygen source to the first oxygen source supply unit 5. This configuration increases the oxygen concentration of the first oxygen source supplied to the combustion chamber 21, thereby accelerating the combustion of fuel. This accelerates the temperature rise of the combustion chamber 21, shortens the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0062] The third oxygen source supply unit 12 supplies the third oxygen source from, for example, the supply port 54 of the first oxygen source supply unit 5. However, the third oxygen source supply unit 12 is not limited to this, and may supply the third oxygen source from, for example, the first communication passage 51 and the second communication passage 52.

[0063] The third oxygen source is a liquid or gas having a higher oxygen concentration than the first oxygen source. The third oxygen source is preferably a gas. The third oxygen source is an oxidizer such as pure oxygen or oxygen-enriched air. The third oxygen source may be the same as or different from the second oxygen source.

[0064] The third oxygen source supply unit 12 includes a third oxygen source supplier (not shown) for supplying the third oxygen source. The third oxygen source supplier may be configured to supply the third oxygen source. In this embodiment, the third oxygen source supplier is a blower, but is not limited to this. When the third oxygen source is a liquid, the second oxygen source supplier may be a liquid pump or the like. The third oxygen source supplier may have the same configuration as the second oxygen source supplier, or may have a different configuration from the second oxygen source supplier. The third oxygen source supply unit may supply the third oxygen source by the first oxygen source supplier 55.

[0065] The first oxygen source adjusting unit preferably adjusts the supply amount of the first oxygen source according to the supply amounts (of oxygen) of the second oxygen source and the third oxygen source. With this configuration, by adjusting the supply amount of the first oxygen source, the supply amount of oxygen to the combustion chamber 21 can be made closer to the theoretical oxygen amount, thereby suppressing an increase in fuel consumption. The adjusting unit preferably adjusts the supply amount of oxygen to the combustion chamber 21 to the theoretical oxygen amount, and more preferably adjusts it to 1.05 times the theoretical oxygen amount.

[0066] [Third embodiment] Next, a third embodiment of the combustion device will be described with reference to Fig. 6. The third embodiment can be configured similarly to the first embodiment except for the configuration described below, so the commonalities will be omitted and differences will be mainly described. Components already described in the first embodiment will be assigned the same reference numerals and redundant description will be omitted. Fig. 6 is a cross-sectional view of the combustion device 1 according to the third embodiment.

[0067] As shown in FIG. 6, in the third embodiment, the second oxygen source supply unit 6 includes a supply pipe 61 (also referred to as the "second oxygen source supply pipe 61") that supplies the second oxygen source. At least a portion of the supply pipe 61 is arranged to pass through the inside of the heat storage body 7. This configuration increases the temperature of the second oxygen source, making it easier to combust the fuel. This reduces the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0068] The supply pipe 61 is arranged to pass through the inside of the heat storage body 7 provided in at least one of the first heat storage chamber 3 and the second heat storage chamber 4. In this embodiment, the supply pipe 61 provided on the first heat storage chamber 3 side passes through the inside of the heat storage body 7 provided in the first heat storage chamber 3, and the supply pipe 61 provided on the second heat storage chamber 4 side passes through the inside of the heat storage body 7 provided in the second heat storage chamber 4, but this is not limited to this.

[0069] The supply pipe 61 is preferably made of ceramics, which can prevent the supply pipe 61 from melting inside the heat storage body 7. When the supply pipe 61 is disposed in a low-temperature part of the heat storage body 7, the supply pipe 61 may be, for example, a metal pipe.

[0070] [Fourth embodiment] Next, a fourth embodiment of the combustion device will be described with reference to Fig. 7. The fourth embodiment can be configured similarly to the first embodiment except for the configuration described below, so the commonalities will be omitted and differences will be mainly described. The same reference numerals will be used for components already described in the first embodiment, and duplicated explanations will be omitted.

[0071] In the fourth embodiment, the second oxygen source supply unit 6 supplies the second oxygen source to the first oxygen source supply unit 5. With this configuration, the concentration of the oxygen source supplied to the combustion chamber 21 via the first heat storage chamber 3 or the second heat storage chamber 4 can be increased, and the combustion of fuel can be accelerated. This reduces the time required for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0072] The second oxygen source supply unit 6 supplies the second oxygen source from, for example, the supply port 54 of the first oxygen source supply unit 5. However, the second oxygen source supply unit 6 is not limited to this, and may supply the second oxygen source from, for example, the first communication passage 51 and the second communication passage 52.

[0073] [1] As described above, in the embodiment, the combustion device 1 comprises: a combustion section 2 having a combustion chamber 21 for burning a fuel containing ammonia; a first heat storage chamber 3 and a second heat storage chamber 4 which are connected to the combustion chamber 21 and are provided with a heat storage body 7, and which alternately store heat from the exhaust gas after combustion in the heat storage body 7 and release heat from the stored heat storage body 7 to a first oxygen source which burns the fuel; a first oxygen source supply section 5 which alternately flows the first oxygen source through the first heat storage chamber 3 and the second heat storage chamber 4 and supplies the first oxygen source to the combustion chamber 21; and a second oxygen source supply section 6 which, at least after the first oxygen source supply section 5 switches the flow destination of the first oxygen source, supplies a second oxygen source having an oxygen concentration higher than that of the first oxygen source to the combustion chamber 21.

[0074] According to this configuration, after the flow destination of the first oxygen source is switched as the temperature of the combustion chamber 21 decreases, the second oxygen source having a higher oxygen concentration than the first oxygen source is supplied to the combustion chamber 21, thereby increasing the oxygen concentration in the combustion chamber 21 and accelerating the combustion of the fuel containing ammonia. This accelerates the temperature rise of the combustion chamber 21, shortens the time it takes for the temperature of the combustion chamber 21 to decrease, and suppresses the generation of nitrogen oxides (NOx).

[0075] [2] Furthermore, in the combustion device 1 described in [1] above, the combustion section 2 may be configured to include a burner 22 for burning fuel, and the second oxygen source supply section 6 may be configured to supply the second oxygen source from the burner 22.

[0076] According to this configuration, by supplying the second oxygen source from the burner 22, the second oxygen source can be supplied to the combustion chamber 21 from near the nozzle (fuel nozzle 223) of the burner 22. This promotes the reaction between the fuel and the second oxygen source, i.e., combustion, reduces the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0077] [3] Furthermore, in the combustion device 1 described in the above [1] or [2], the second oxygen source supply unit 6 may be configured to supply the second oxygen source to the combustion chamber 21 before burning the fuel.

[0078] This configuration increases the oxygen concentration in the combustion chamber 21, making it easier to burn fuel. This speeds up the temperature rise in the combustion chamber 21, shortens the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0079] [4] In addition, in the combustion device 1 described in any one of the above [1] to [3], the second oxygen source is preferably configured to be mixed with the fuel before combustion.

[0080] According to this configuration, by mixing the second oxygen source with the fuel, it is possible to promote the reaction between the fuel and the second oxygen source, i.e., combustion, and accelerate the temperature rise in the combustion chamber 21. This reduces the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0081] [5] Furthermore, the combustion device 1 described in any one of the above [1] to [4] may be configured to include a third oxygen source supply unit 12 that supplies a third oxygen source having an oxygen concentration higher than that of the first oxygen source to the first oxygen source supply unit 5.

[0082] According to this configuration, the oxygen concentration of the first oxygen source supplied to the combustion chamber 21 can be increased, and the combustion of fuel can be accelerated. This accelerates the temperature rise of the combustion chamber 21, shortens the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0083] [6] In addition, in the combustion device 1 described in any one of the above [1] to [5], the second oxygen source supply unit 6 may be configured to include a supply pipe 61 that supplies the second oxygen source, and at least a portion of the supply pipe 61 may be arranged to pass through the inside of the heat storage body 7.

[0084] With this configuration, the temperature of the second oxygen source can be increased, making it easier to burn the fuel, thereby reducing the time it takes for the temperature of the combustion chamber 21 to drop and suppressing the generation of NOx.

[0085] [7] In addition, in the combustion device 1 described in any one of the above [1] to [6], the second oxygen source supply unit 6 may be configured to supply the second oxygen source to the first oxygen source supply unit 5.

[0086] According to this configuration, the concentration of the oxygen source supplied to the combustion chamber 21 via the first heat storage chamber 3 or the second heat storage chamber 4 can be increased, and the combustion of fuel can be accelerated. This reduces the time it takes for the temperature of the combustion chamber 21 to drop, and suppresses the generation of NOx.

[0087] [8] In addition, in the combustion device 1 described in any one of the above [1] to [7], the first oxygen source supply unit 5 is preferably configured to include an adjustment unit that adjusts the supply amount of the first oxygen source depending on the supply amount of the second oxygen source.

[0088] According to this configuration, by adjusting the supply amount of the first oxygen source, the supply amount of oxygen from the first oxygen source and the second oxygen source can be made closer to the theoretical oxygen amount, thereby suppressing an increase in fuel consumption.

[0089] The combustion device 1 is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. Furthermore, it goes without saying that various modifications can be made to the combustion device 1 without departing from the spirit of the present invention. For example, it goes without saying that one or more of the configurations according to the above-described embodiment or the configurations according to the various modified examples described below may be arbitrarily selected and adopted in the configuration according to any of the above-described embodiments.

[0090] (A) In the above embodiment, the second oxygen source injection port 224 is formed in an annular shape so as to surround the fuel injection port 223, but this is not limited thereto. For example, as shown in FIGS. 8(a) to 8(g), the second oxygen source injection port 224 may be formed in a circular shape, and a plurality of second oxygen source injection ports 224 (for example, two to eight) may be arranged so as to surround the fuel injection port 223. The hole diameter of the second oxygen source injection port 224 is, for example, smaller than the hole diameter of the fuel injection port 223. Furthermore, for example, the second oxygen source injection port 224 may be an arc-shaped slit as shown in FIG. 8(h).

[0091] (B) As shown in Fig. 9, the nozzle 220 may include a junction channel 226 where the fuel and the second oxygen source join within the nozzle 220. This allows the fuel and the second oxygen source to be premixed and then injected from the nozzle 220. In such a configuration, the junction channel 226 is provided, for example, on the tip surface 220a side of the nozzle 220. The junction channel 226 communicates with the fuel flow channel 221 and the second oxygen source flow channel 222. The fuel injection port 223 (second oxygen source injection port 224) communicates with the junction channel 226. Note that the fuel supply unit 10 and the second oxygen source supply unit 6 may be connected to one flow channel, and this flow channel may serve as the junction channel.

[0092] (C) In the above embodiment, the first oxygen source supply unit 5 is configured to include a first oxygen source regulator that regulates the supply amount of the first oxygen source, but this is not limiting. For example, the first oxygen source supply unit 5 may be configured not to include a first oxygen source regulator.

[0093] (D) The fuel supply unit 10 may be provided with a fuel heating unit that heats the fuel to a temperature (e.g., 300°C) that does not decompose ammonia. This increases the temperature of the fuel, making it easier to burn. As a result, the time it takes for the temperature of the combustion chamber 21 to drop can be reduced, and NOx generation can be suppressed. [Explanation of symbols]

[0094] 1...combustion device, 2...combustion section, 21...combustion chamber, 22...burner, 220...nozzle, 220a...tip surface, 221...fuel flow path, 222...second oxygen source flow path, 223...fuel injection port, 224...second oxygen source injection port, 225...cooling section, 226...junction passage, 23...communication section, 3...first heat storage chamber, 4...second heat storage chamber, 5...first oxygen source supply section, 51...first communication passage, 52...second communication passage, 53 ...switching unit, 531...switching valve, 532...switching path, 54...supply port, 55...first oxygen source supplier, 6...second oxygen source supplier, 61...supply pipe, 7...heat storage body, 8...discharge unit, 81...reaction tower, 82...dust collector, 83...chimney, 84...first exhaust gas flow path, 85...second exhaust gas flow path, 86...third exhaust gas flow path, 9...temperature measurement unit, 10...fuel supplier, 11...raw material supplier, 12...third oxygen source supplier

Claims

1. a combustion unit having a combustion chamber for burning a fuel containing ammonia; a first heat storage chamber and a second heat storage chamber that are connected to the combustion chamber and have a heat storage body, in which heat is stored from the exhaust gas after combustion in the heat storage body and heat is released from the stored heat storage body to a first oxygen source that combusts the fuel; a first oxygen source supply unit that alternately flows the first oxygen source through the first heat storage chamber and the second heat storage chamber and supplies the first oxygen source to the combustion chamber; a second oxygen source supply unit that supplies a second oxygen source to the combustion chamber after at least the first oxygen source supply unit switches the flow destination of the first oxygen source.

2. the combustion unit includes a burner for burning the fuel, The combustion device according to claim 1 , wherein the second oxygen source supply unit supplies the second oxygen source from the burner.

3. The combustion device of claim 2 , wherein the second oxygen source supply supplies the second oxygen source to the combustion chamber before combusting the fuel.

4. 3. The combustion device of claim 2, wherein the second oxygen source is mixed with the fuel prior to combustion.

5. The combustion device according to claim 2 , further comprising a third oxygen source supply unit that supplies a third oxygen source having an oxygen concentration higher than that of the first oxygen source to the first oxygen source supply unit.

6. the second oxygen source supply unit includes a supply pipe that supplies the second oxygen source, The combustion device according to claim 2 , wherein at least a portion of the supply pipe is disposed so as to pass through the inside of the heat storage body.

7. The combustion apparatus of claim 1 , wherein the second oxygen source supply supplies the second oxygen source to the first oxygen source supply.

8. 8. The combustion device according to claim 1, wherein the first oxygen source supply unit includes an adjusting unit that adjusts the supply amount of the first oxygen source depending on the supply amount of the second oxygen source.

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