Combustion device

Abstract

A combustion device (10) is provided with: at least one first ammonia nozzle (41) having a first injection port (41a) facing the inside of a furnace; a plurality of second ammonia nozzles (42) which have second injection ports (42a) facing the inside of the furnace, and which are disposed at intervals around the at least one first ammonia nozzle (41) in the circumferential direction surrounding the at least one first ammonia nozzle (41); an air flow path (45) that communicates with the inside of the furnace, is disposed around the plurality of second ammonia nozzles (42), and is provided with a swirler (46); and a control device (8) that controls the flow rate of the ammonia injected from the first injection port (41a) and the flow rate of the ammonia injected from the second injection port (42a) such that the flow rate of the ammonia injected from the second injection port (42a) is faster than the flow rate of the ammonia injected from the first injection port (41a).

Description

Technical Field

[0001] The present disclosure relates to a combustion device. This application claims the benefit of priority based on Japanese Patent Application No. 2022-196868 filed on December 9, 2022, the contents of which are hereby incorporated by reference into this application. Background Art

[0002] Among the burners installed in furnaces such as boilers, there are burners with ammonia nozzles that inject ammonia as fuel. By using ammonia as fuel, the emission of carbon dioxide can be reduced. For example, Patent Document 1 discloses a burner that mixes pulverized coal and ammonia as fuel.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-086189 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Since ammonia contains a large amount of nitrogen atoms, nitrogen oxides (hereinafter also referred to as NOx) are easily generated when ammonia is used as a fuel. Therefore, it is desired to propose a new method for suppressing the generation of NOx.

[0008] An object of the present disclosure is to provide a combustion device capable of suppressing the generation of NOx.

[0009] Solutions to Solve Problems

[0010] In order to solve the above-mentioned problems, the combustion device disclosed in the present invention comprises: at least one first ammonia nozzle, which has a first injection port facing the furnace; a plurality of second ammonia nozzles, which have second injection ports facing the furnace and are arranged around the at least one first ammonia nozzle at intervals in the circumferential direction surrounding the at least one first ammonia nozzle; an air flow path, which is connected to the furnace, is arranged around the plurality of second ammonia nozzles and is provided with a swirler; and a control device, which controls the flow rate of ammonia injected from the first injection port and the flow rate of ammonia injected from the second injection port, so that the flow rate of ammonia injected from the second injection port is faster than the flow rate of ammonia injected from the first injection port.

[0011] The at least one first ammonia nozzle may include a plurality of first ammonia nozzles arranged at intervals in the circumferential direction, and the first injection port of each of the plurality of first ammonia nozzles may face the center in the circumferential direction when viewed from within the furnace.

[0012] The second injection port may face a direction inclined with respect to a central axis direction of the second ammonia nozzle, and the second ammonia nozzle may be provided so as to be rotatable about the central axis.

[0013] Effects of the Invention

[0014] According to the present disclosure, the generation of NOx can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram showing a boiler according to an embodiment of the present disclosure.

[0016] Figure 2 It is a schematic diagram showing a combustion device according to an embodiment of the present disclosure.

[0017] Figure 3 It is a front view showing the burner according to the embodiment of the present disclosure.

[0018] Figure 4 It is a diagram for explaining the combustion state in the combustion device according to the embodiment of the present disclosure.

[0019] Figure 5 It is a diagram for explaining the combustion state of a comparative example.

[0020] Figure 6 It is a schematic diagram showing a combustion device according to a first modified example.

[0021] Figure 7 It is a front view showing a burner according to a first modified example.

[0022] Figure 8 It is a schematic diagram showing a combustion device according to a second modified example. DETAILED DESCRIPTION

[0023] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for easy understanding and do not limit the present disclosure unless otherwise specified. In addition, in this specification and the accompanying drawings, for elements having substantially the same function and structure, repeated descriptions are omitted by marking the same figure numbers, and elements that are not directly related to the present disclosure will be omitted from the drawings.

[0024] Figure 1 Schematic diagram showing the boiler 1 of this embodiment. Figure 1 As shown, the boiler 1 includes a furnace 2 , a flue 3 , and a burner 4 .

[0025] The furnace 2 burns fuel to generate combustion heat. The furnace 2 has a cylindrical shape such as a rectangular cylindrical shape extending in the vertical direction. In the furnace 2, high-temperature combustion gas is generated by the combustion of fuel. A discharge port 2a is provided at the bottom of the furnace 2 to discharge ash generated by the combustion of fuel to the outside.

[0026] The flue 3 is a passage for guiding the combustion gas generated in the furnace 2 as exhaust gas to the outside. The flue 3 is connected to the upper part of the furnace 2. The flue 3 includes a horizontal flue 3a and a rear flue 3b. The horizontal flue 3a extends horizontally from the upper part of the furnace 2. The rear flue 3b extends downward from the end of the horizontal flue 3a.

[0027] The boiler 1 includes a superheater (not shown) installed on the top of the furnace 2. In the superheater, heat exchange between the combustion heat generated by the furnace 2 and water is performed. As a result, steam is generated. Figure 1 Various equipment such as reheater, economizer or air preheater not shown in the figure.

[0028] The burner 4 is provided on the wall of the lower part of the furnace 2. In the furnace 2, a plurality of burners 4 are provided at intervals in the circumferential direction of the furnace 2. Figure 1 Although not shown in the figure, a plurality of burners 4 are also arranged at intervals in the extending direction of the furnace 2, that is, in the vertical direction. The burners 4 inject ammonia as fuel into the internal space 2b of the furnace 2. The ammonia injected from the burners 4 burns, thereby forming a flame F in the internal space 2b of the furnace 2. In addition, the furnace 2 is provided with an ignition device (not shown) for igniting the ammonia injected from the burners 4.

[0029] Figure 2 Schematic diagram showing the combustion device 10 of this embodiment. Figure 2 As shown, the combustion device 10 includes a burner 4 , an ammonia tank 5 , a first flow rate regulating valve 6 , a second flow rate regulating valve 7 , and a control device 8 . Figure 3 1 is a front view showing the burner 4 of this embodiment. Specifically, Figure 3 This is a diagram showing the burner 4 as viewed from the inside of the furnace 2 .

[0030] like Figure 2 As shown, the burner 4 is mounted on the wall of the furnace 2 outside the furnace 2. The burner 4 includes a first ammonia nozzle 41, a plurality of second ammonia nozzles 42, a nozzle housing 43, a casing 44, an air flow path 45, and a swirler 46.

[0031] The first ammonia nozzle 41 and the plurality of second ammonia nozzles 42 are nozzles for spraying ammonia. The first ammonia nozzle 41 and the plurality of second ammonia nozzles 42 have a substantially cylindrical shape. The first ammonia nozzle 41 and the plurality of second ammonia nozzles 42 are housed in the nozzle shell 43 in a state of being held in the nozzle shell 43. The nozzle shell 43 has a substantially cylindrical shape. The first ammonia nozzle 41, the plurality of second ammonia nozzles 42, and the nozzle shell 43 extend in the same direction. Specifically, the first ammonia nozzle 41, the plurality of second ammonia nozzles 42, and the nozzle shell 43 extend in a direction intersecting with the wall of the furnace 2 (specifically, a substantially orthogonal direction).

[0032] The first ammonia nozzle 41 extends on the central axis of the nozzle housing 43. The plurality of second ammonia nozzles 42 are arranged around the first ammonia nozzle 41. The plurality of second ammonia nozzles 42 are arranged at intervals in the circumferential direction surrounding the first ammonia nozzle 41. Figure 3 In the example of FIG. 1 , the number of the second ammonia nozzles 42 is eight. However, the number of the second ammonia nozzles 42 may be other than eight. Figure 3 In the example of FIG. 4 , the plurality of second ammonia nozzles 42 are arranged at equal intervals in the circumferential direction of the nozzle case 43 . However, the plurality of second ammonia nozzles 42 may be arranged at unequal intervals in the circumferential direction of the nozzle case 43 .

[0033] The circumferential direction surrounding the first ammonia nozzle 41 coincides with the circumferential direction of the nozzle shell 43. Hereinafter, this direction is also referred to as the circumferential direction of the burner 4. The extending direction of the central axis of the circumferential direction surrounding the first ammonia nozzle 41 coincides with the central axis direction of the nozzle shell 43. Hereinafter, this direction is also referred to as the central axis direction of the burner 4. The radial direction relative to the circumferential direction surrounding the first ammonia nozzle 41 coincides with the radial direction of the nozzle shell 43. Hereinafter, this direction is also referred to as the radial direction of the burner 4.

[0034] At the front end portion ( Figure 2 The first injection port 41a is provided at the right end of the furnace 2. The first injection port 41a faces the inner space 2b of the furnace 2. The ammonia supplied to the first ammonia nozzle 41 is injected from the first injection port 41a to the inner space 2b of the furnace 2. Specifically, the first injection port 41a faces the central axis direction of the first ammonia nozzle 41. The flow of ammonia injected from the first injection port 41a is Figure 2 The arrow A1 schematically shows the direction of ammonia injection from the first injection port 41 a. As shown by the arrow A1 , the injection direction of ammonia from the first injection port 41 a is the central axis direction of the combustor 4 .

[0035] At the front end portion ( Figure 2 A second injection port 42a is provided at the right end of the second ammonia nozzle 42. The second injection port 42a faces the internal space 2b of the furnace 2. Ammonia supplied to each second ammonia nozzle 42 is injected from the second injection port 42a into the internal space 2b of the furnace 2. Specifically, the second injection port 42a faces a direction inclined relative to the central axis direction of the second ammonia nozzle 42. The flow of ammonia injected from the second injection port 42a is determined by Figure 2 and Figure 3 As shown by arrow A2, the injection direction of ammonia from the second injection port 42a is the circumferential direction of the burner 4 when viewed from the internal space 2b of the furnace 2. That is, the second injection port 42a faces a direction inclined toward the circumferential direction of the burner 4 relative to the central axis direction of the burner 4.

[0036] In other words, the second injection port 42a faces the tangential direction of the nozzle housing 43 when viewed along the central axis of the burner 4. Therefore, the ammonia injected from the second injection port 42a flows toward the radially outer side of the burner 4 in parallel with the tangential direction of the nozzle housing 43 when viewed along the central axis of the burner 4, as shown by arrow A2. Figure 2 As shown by arrow A2, the ammonia injected from the second injection port 42a flows radially outward over the nozzle housing 43 as it moves away from the second injection port 42a. Figure 2 In the figure, the accurate illustration of the inclination of the second injection port 42a is omitted.

[0037] like Figure 2 As shown, the first ammonia nozzle 41 and each second ammonia nozzle 42 are connected to the ammonia tank 5 via a flow path. The flow path connected to the ammonia tank 5 is branched and connected to the first ammonia nozzle 41 and each second ammonia nozzle 42 respectively. Ammonia is stored in the ammonia tank 5. For example, ammonia is stored in a liquid state in the ammonia tank 5. The ammonia stored in the ammonia tank 5 is gasified by a gasifier not shown. The gasified ammonia is supplied to the first ammonia nozzle 41 and each second ammonia nozzle 42 through the flow path.

[0038] The first flow regulating valve 6 is provided at a portion connected to the first ammonia nozzle 41 in the flow path connected to the ammonia tank 5. The first flow regulating valve 6 regulates the flow rate of ammonia supplied from the ammonia tank 5 to the first ammonia nozzle 41. By adjusting the opening of the first flow regulating valve 6, the flow rate of ammonia supplied from the ammonia tank 5 to the first ammonia nozzle 41 is regulated. Thus, the flow rate of ammonia injected from the first injection port 41a of the first ammonia nozzle 41 is regulated.

[0039] The second flow regulating valve 7 is provided at a portion connected to the plurality of second ammonia nozzles 42 in the flow path connected to the ammonia tank 5. The second flow regulating valve 7 regulates the flow rate of ammonia supplied from the ammonia tank 5 to each second ammonia nozzle 42. By adjusting the opening of the second flow regulating valve 7, the flow rate of ammonia supplied from the ammonia tank 5 to each second ammonia nozzle 42 is regulated. Thus, the flow rate of ammonia injected from the second injection port 42a of the second ammonia nozzle 42 is regulated. However, the second flow regulating valve 7 may also be provided at each second ammonia nozzle 42.

[0040] The housing 44 covers the front end portion ( Figure 2 The housing 44 has a substantially truncated cone shape and is coaxially arranged with the nozzle housing 43. An air flow path 45 is defined by the inner surface of the housing 44 and the outer peripheral surface of the nozzle housing 43.

[0041] The air flow path 45 covers the front end portion of the nozzle housing 43 ( Figure 2The air flow path 45 is arranged in a manner between the right end of the air flow path 45 and the furnace 2. That is, the air flow path 45 is arranged around the plurality of second ammonia nozzles 42. Air is supplied to the air flow path 45. At the front end ( Figure 2 The air injection port 45a is formed at the right end of the furnace 2. The air injection port 45a faces the inner space 2b of the furnace 2. The air injection port 45a has a circular ring shape. The flow of air through the air flow path 45 is Figure 2 The arrow A3 is schematically shown. Figure 2 As shown by arrow A3 , the air that has passed through the air flow path 45 is ejected from the air ejection port 45 a toward the internal space 2 b of the furnace 2 .

[0042] The air flow path 45 is provided with a swirler 46. The swirler 46 has swirling blades that impart a swirling force in the circumferential direction of the burner 4 to the air flowing in the air flow path 45. Therefore, the air injected from the air injection port 45a of the air flow path 45 is sent to the internal space 2b of the furnace 2 while swirling in the circumferential direction of the burner 4.

[0043] exist Figure 2 In the example of FIG. 4 , the air flow path 45 has one path. However, the air flow path 45 may be partially divided so that the air flow path 45 branches. Figure 2 In the example of FIG. 4 , the cyclone 46 is provided at one location in the flow direction of the air in the air flow path 45 . However, a plurality of cyclones 46 may be provided at intervals in the flow direction of the air in the air flow path 45 .

[0044] The control device 8 includes a central processing unit (CPU), a ROM storing programs, a RAM as a work area, etc., and controls the entire combustion device 10. In particular, the control device 8 controls the operation of the first flow regulating valve 6 and the second flow regulating valve 7. Specifically, the control device 8 can control the flow rate of ammonia injected from the first injection port 41a of the first ammonia nozzle 41 by controlling the opening of the first flow regulating valve 6. In addition, the control device 8 can control the flow rate of ammonia injected from the second injection port 42a of the second ammonia nozzle 42 by controlling the opening of the second flow regulating valve 7.

[0045] Figure 4 1 is a diagram for explaining the combustion state in the combustion device 10 of this embodiment. As described above, ammonia is injected from the burner 4 into the internal space 2b of the furnace 2. Figure 4 As shown, flame F is formed in the inner space 2 b of the furnace 2 .

[0046] In the combustion device 10, the air injected from the air injection port 45a of the air flow path 45 (see arrow A3) swirls in the circumferential direction of the burner 4. Then, as shown by arrow A2, ammonia is injected from the second injection port 42a of the second ammonia nozzle 42 toward the air swirling in the circumferential direction of the burner 4. Thus, the ammonia injected from the second injection port 42a is effectively mixed with the air while swirling together with the air. Therefore, the ammonia injected from the second injection port 42a is rapidly burned.

[0047] exist Figure 4 In the region R in the middle, ammonia injected from the second injection port 42a is effectively mixed with air. The region R is formed near the front end of the burner 4 and is located radially outside the burner 4 relative to the flame F. The flame F extends from the inside of the region R to the inside of the furnace 2. In the region R, the ratio of air to ammonia becomes locally low.

[0048] In the combustion device 10, the control device 8 controls the flow rate of ammonia injected from the first injection port 41a of the first ammonia nozzle 41 and the flow rate of ammonia injected from the second injection port 42a of the second ammonia nozzle 42 so that the flow rate of ammonia injected from the second injection port 42a is faster than the flow rate of ammonia injected from the first injection port 41a. Figure 4 In FIG. 4 , the magnitude relationship between the flow rate of ammonia injected from the second injection port 42 a and the flow rate of ammonia injected from the first injection port 41 a is expressed by the difference in thickness between the arrow A2 and the arrow A1 .

[0049] like Figure 4 As shown in FIG. 1 , the flow rate of ammonia injected from the second injection port 42a is faster than the flow rate of ammonia injected from the first injection port 41a, and thus, compared with the case where the flow rate of ammonia injected from the second injection port 42a is slower than the flow rate of ammonia injected from the first injection port 41a, the region R where the ratio of air to ammonia is locally low becomes larger. In addition, since the flow rate of ammonia injected from the second injection port 42a is fast, mixing with combustion air can be promoted. Therefore, stable combustion can be performed while suppressing the generation of NOx.

[0050] In particular, in the combustion device 10, if Figure 3 As shown in FIG. 1 , the injection direction of ammonia from the second injection port 42a is the circumferential direction of the burner 4 when the burner 4 is viewed from the inner side of the furnace 2. As a result, the ammonia injected from the second injection port 42a is easily mixed with the air while swirling together with the air. Therefore, the combustion stability of ammonia and the shape stability of the flame F are improved. However, the injection direction of ammonia from the second injection port 42a is not limited to Figure 3For example, the second injection port 42a may face the central axis direction of the second ammonia nozzle 42, so that the injection direction of ammonia from the second injection port 42a is the central axis direction of the burner 4. For example, when viewed along the central axis direction of the burner 4, the second injection port 42a may not face the tangential direction of the nozzle housing 43, but may face a position radially inward or outward of the tangential direction.

[0051] In particular, in the combustion device 10, the plurality of second ammonia nozzles 42 are arranged at intervals in the circumferential direction surrounding the first ammonia nozzle 41. Therefore, ammonia is respectively injected from the plurality of second injection ports 42a separated from each other. Thus, for example, compared with the case where the second ammonia nozzle 42 is assumed to be a cylindrical nozzle covering the first ammonia nozzle 41 and ammonia is injected from one second injection port 42a, the total contact area of ​​ammonia injected from the second injection port 42a and the air becomes larger. Therefore, ammonia is easily effectively mixed with air. Therefore, the combustion stability of ammonia and the shape stability of the flame F are improved.

[0052] Figure 5 It is a diagram for explaining the combustion state of a comparative example.

[0053] exist Figure 5 In the example of FIG. 4 , the flow rate of ammonia injected from the first injection port 41a of the first ammonia nozzle 41 and the flow rate of ammonia injected from the second injection port 42a of the second ammonia nozzle 42 are controlled so that the flow rate of ammonia injected from the second injection port 42a is slower than the flow rate of ammonia injected from the first injection port 41a. Figure 5 In FIG. 4 , the magnitude relationship between the flow rate of ammonia injected from the second injection port 42 a and the flow rate of ammonia injected from the first injection port 41 a is expressed by the difference in thickness between the arrow A2 and the arrow A1 .

[0054] like Figure 5 As shown in FIG. 4 , the flow rate of ammonia injected from the second injection port 42a is slower than the flow rate of ammonia injected from the first injection port 41a, and thus the region R where the ratio of air to ammonia is locally lowered becomes smaller. In addition, since the flow rate of ammonia injected from the second injection port 42a is slow, it is difficult to promote mixing with combustion air. Therefore, it may be difficult to perform stable combustion while suppressing the generation of NOx.

[0055] As described above, the combustion device 10 comprises: at least one first ammonia nozzle 41, which has a first injection port 41a facing the furnace (in the above example, the internal space 2b of the furnace 2); a plurality of second ammonia nozzles 42, which have second injection ports 42a facing the furnace and are arranged at intervals around the at least one first ammonia nozzle 41 in the circumferential direction surrounding the at least one first ammonia nozzle 41; an air flow path 45, which is connected to the furnace, is arranged around the plurality of second ammonia nozzles 42, and is provided with a swirler 46; and a control device 8, which controls the flow rate of ammonia injected from the first injection port 41a and the flow rate of ammonia injected from the second injection port 42a, so that the flow rate of ammonia injected from the second injection port 42a is faster than the flow rate of ammonia injected from the first injection port 41a. Thus, by making the flow rate of ammonia injected from the second injection port 42a faster than the flow rate of ammonia injected from the first injection port 41a, the region R where the ratio of air to ammonia is locally low becomes larger than the case where the flow rate of ammonia injected from the second injection port 42a is slower than the flow rate of ammonia injected from the first injection port 41a. In addition, since the flow rate of ammonia injected from the second injection port 42a is fast, mixing with combustion air can be promoted. Therefore, stable combustion can be performed while suppressing the generation of NOx. As described above, according to the combustion device 10, the generation of NOx can be suppressed.

[0056] Furthermore, in the combustion device 10, by injecting ammonia from a plurality of second injection ports 42a separated from each other, the total contact area between the ammonia injected from the second injection ports 42a and the air becomes larger. Therefore, ammonia is easily mixed with air effectively. Therefore, the combustion stability of ammonia and the shape stability of the flame F are improved.

[0057] Figure 6 1 is a schematic diagram showing a combustion device 10A according to a first modification. The combustion device 10A is different from the above-described combustion device 10 in that the burner 4 is replaced with a burner 4A. Figure 7 4A is a front view showing a burner 4A according to a first modification. Specifically, Figure 7 This is a diagram showing the burner 4A as viewed from the inside of the furnace 2 .

[0058] like Figure 6 and Figure 7 As shown, in the burner 4A, the difference from the above-mentioned burner 4 is that the number of the first ammonia nozzles 41 is plural. Specifically, in the burner 4A, the plural first ammonia nozzles 41 are arranged at intervals in the circumferential direction of the burner 4A. Figure 7 In the example of FIG. 4 , the number of the first ammonia nozzles 41 is four. However, the number of the first ammonia nozzles 41 may be other than four. Figure 7In the example of FIG. 4 , the plurality of first ammonia nozzles 41 are arranged at equal intervals in the circumferential direction of the combustor 4A. However, the plurality of first ammonia nozzles 41 may be arranged at unequal intervals in the circumferential direction of the combustor 4A.

[0059] In the burner 4A, each first injection port 41a faces a direction inclined with respect to the central axis direction of the burner 4A. The flow of ammonia injected from the first injection port 41a is determined by Figure 6 and Figure 7 As shown by arrow A1, the injection direction of ammonia from each first injection port 41a is toward the central axis of the burner 4A when viewed from the internal space 2b of the furnace 2. That is, each first injection port 41a faces the center of the circumferential direction of the burner 4A when viewed from the internal space 2b of the furnace 2.

[0060] As described above, in the first variant, at least one first ammonia nozzle 41 includes a plurality of second ammonia nozzles 42 arranged at intervals in the circumferential direction surrounding the at least one first ammonia nozzle 41 (i.e., the circumferential direction of the burner 4A), and the first injection ports 41a of the plurality of first ammonia nozzles 41 face the center of the circumferential direction when viewed from the furnace (in the above example, the internal space 2b of the furnace 2). Thus, by adjusting the flow rate of ammonia injected from each first injection port 41a, the position where the ammonia injected from each first injection port 41a merges and mixes in the central axis direction of the burner 4A can be adjusted. Therefore, the position where the ammonia injected from each first injection port 41a merges and mixes can be adjusted in the central axis direction of the burner 4A according to the combustion state such as the shape of the flame F in the combustion device 10A. Thus, the performance of suppressing the generation of NOx, the combustion stability of ammonia, and the shape stability of the flame F can be more appropriately improved according to the combustion state in the combustion device 10A.

[0061] Figure 8 1 is a schematic diagram showing a combustion device 10B according to a second modification. The combustion device 10B is different from the above-described combustion device 10 in that the burner 4 is replaced with a burner 4B.

[0062] like Figure 8 As shown by arrow A4, in the burner 4B, compared with the above-mentioned burner 4, the difference is that the second ammonia nozzle 42 is set to be able to rotate around the central axis of the second ammonia nozzle 42. For example, the second ammonia nozzle 42 is supported by a bearing not shown in the figure so that it can rotate. In addition, a driving device 47 for rotating the second ammonia nozzle 42 is provided in the burner 4B. For example, the driving device 47 is a motor for rotating the second ammonia nozzle 42, and is provided relative to each second ammonia nozzle 42. The control device 8 can rotate the second ammonia nozzle 42 by controlling the operation of the driving device 47.

[0063] As described above, in the second modified example, the second ammonia nozzle 42 is provided so as to be able to rotate about the central axis of the second ammonia nozzle 42. And, as described above, the second injection port 42a faces a direction inclined relative to the central axis direction of the second ammonia nozzle 42. Therefore, by rotating the second ammonia nozzle 42, the injection direction of ammonia from the second injection port 42a can be changed. Therefore, the injection direction of ammonia from the second injection port 42a can be adjusted according to the combustion state such as the shape of the flame F in the combustion device 10B. Thus, the performance of suppressing the generation of NOx, the combustion stability of ammonia, and the shape stability of the flame F can be more appropriately improved according to the combustion state in the combustion device 10B.

[0064] The combustion apparatus 10B of the second modification is an example in which the second ammonia nozzle 42 is rotatable and a driving device 47 is added to the combustion apparatus 10. However, the second ammonia nozzle 42 may be rotatable and a driving device 47 may be added to the combustion apparatus 10A of the first modification.

[0065] The embodiments of the present disclosure are described above with reference to the accompanying drawings, but the present disclosure is certainly not limited to the embodiments. Obviously, as long as one is skilled in the art, various changes or modifications can be thought of within the scope of the claims, and it should be understood that they also belong to the technical scope of the present disclosure.

[0066] For example, in the above description, an example in which the combustion devices 10, 10A, and 10B are installed in the furnace 2 of the boiler 1 is described. However, the combustion devices 10, 10A, and 10B can be used in various furnaces of equipment other than the boiler 1.

[0067] For example, in the above description, an example is described in which the burners 4, 4A, 4B that inject ammonia as fuel are provided in the furnace 2 of the boiler 1. However, in the furnace 2 of the boiler 1, in addition to the burners 4, 4A, 4B that inject ammonia as fuel, a burner that injects pulverized coal as fuel may be provided.

[0068] For example, in the above description, an example is described in which the burners 4, 4A, and 4B inject ammonia as the fuel. However, the burners 4, 4A, and 4B may inject pulverized coal as the fuel in addition to ammonia.

[0069] The present disclosure can promote the use of ammonia that can achieve reductions in CO2 emissions, and thus, for example, can contribute to Goal 7 of the Sustainable Development Goals (SDGs) to "ensure access to affordable, reliable, sustainable and modern energy for all" and Goal 13 to "take urgent action to combat climate change and its impacts."

[0070] Explanation of symbols

[0071] 2—furnace; 8—control device; 10—combustion device; 10A—combustion device; 10B—combustion device; 41—first ammonia nozzle; 41a—first injection port; 42—second ammonia nozzle; 42a—second injection port; 45—air flow path; 46—cyclone.

Claims

1. A combustion device, characterized in that: have: at least one first ammonia nozzle having a first injection port facing into the furnace; a plurality of second ammonia nozzles having second injection ports facing the furnace and arranged around the at least one first ammonia nozzle at intervals in a circumferential direction surrounding the at least one first ammonia nozzle; an air flow path, which is communicated with the furnace, is arranged around the plurality of second ammonia nozzles, and is provided with a cyclone; and A control device controls the flow rate of ammonia injected from the first injection port and the flow rate of ammonia injected from the second injection port so that the flow rate of ammonia injected from the second injection port is faster than the flow rate of ammonia injected from the first injection port.

2. The combustion device according to claim 1, characterized in that: The at least one first ammonia nozzle includes a plurality of first ammonia nozzles arranged at intervals in the circumferential direction. The first injection port of each of the plurality of first ammonia nozzles faces the center in the circumferential direction when viewed from within the furnace.

3. The combustion device according to claim 1 or 2, characterized in that: The second injection port faces a direction inclined with respect to the central axis direction of the second ammonia nozzle. The second ammonia nozzle is provided so as to be rotatable about the central axis.

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