JP7816486B2 - Combustion equipment - Google Patents

Description

This application claims the benefit of priority from Japanese Patent Application No. 2022-196868, filed December 9, 2022, the contents of which are incorporated herein by reference.

Among burners installed in furnaces such as boilers, there are burners having ammonia nozzles that inject ammonia as fuel. Using ammonia as fuel reduces carbon dioxide emissions. For example, Patent Document 1 discloses a burner that mixes pulverized coal and ammonia as fuel.

JP 2019-086189 A

Ammonia contains a large amount of nitrogen atoms, so when ammonia is used as a fuel, nitrogen oxides (hereinafter also referred to as NOx) are likely to be generated. Therefore, new proposals for suppressing the generation of NOx are desired.

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

In order to solve the above problems, the combustion apparatus of the present disclosure includes at least one first ammonia nozzle having a first injection port facing the interior of a furnace; a plurality of second ammonia nozzles having second injection ports facing the interior of the furnace and arranged at intervals in a circumferential direction surrounding the at least one first ammonia nozzle; an air flow path that communicates with the interior of the furnace, is arranged around the plurality of second ammonia nozzles, and is provided with a swirler; and a control device that 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 , and so that a region where the ratio of air to ammonia is locally low is located around a flame formed in the furnace .
The direction of injection of ammonia from the second injection port may be in the circumferential direction when viewed from inside the furnace.

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

The second injection port faces in a direction inclined with respect to the central axis direction of the second ammonia nozzle, and the second ammonia nozzle is provided so as to be rotatable about its central axis , and the control device may adjust the injection direction of ammonia from the second injection port by rotating the second ammonia nozzle according to the combustion state in the combustion device .

According to the present disclosure, the generation of NOx can be suppressed.

FIG. 1 is a schematic diagram illustrating a boiler according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating a combustion device according to an embodiment of the present disclosure. FIG. 3 is a front view of a burner according to an embodiment of the present disclosure. FIG. 4 is a diagram for explaining the combustion state in the combustion device according to the embodiment of the present disclosure. FIG. 5 is a diagram for explaining a combustion state according to a comparative example. FIG. 6 is a schematic diagram showing a combustion device according to a first modified example. FIG. 7 is a front view showing a burner according to a first modified example. FIG. 8 is a schematic diagram showing a combustion device according to a second modified example.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for ease of understanding and, unless otherwise specified, do not limit the present disclosure. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

1 is a schematic diagram showing a boiler 1 according to this embodiment. As shown in FIG. 1, the boiler 1 includes a furnace 2, a flue 3, and a burner 4.

The furnace 2 burns fuel to generate combustion heat. The furnace 2 has a cylindrical shape, such as a rectangular cylindrical shape, extending vertically. In the furnace 2, high-temperature combustion gas is generated by the combustion of fuel. An outlet 2a is provided at the bottom of the furnace 2 to discharge ash generated by the combustion of the fuel to the outside.

The flue 3 is a passage that guides the combustion gas generated in the furnace 2 to the outside as exhaust gas. The flue 3 is connected to the upper part of the furnace 2. The flue 3 has 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.

The boiler 1 includes a superheater (not shown) installed above the furnace 2. In the superheater, heat is exchanged between the combustion heat generated in the furnace 2 and water, thereby generating steam. The boiler 1 may also include various devices such as a reheater, an economizer, or an air preheater (not shown in FIG. 1).

The burners 4 are provided on the lower wall of the furnace 2. A plurality of burners 4 are provided in the furnace 2 at intervals in the circumferential direction of the furnace 2. Although not shown in FIG. 1 , the plurality of burners 4 are also provided at intervals in the vertical direction, which is the extension direction of the furnace 2. The burners 4 inject ammonia as fuel into the internal space 2b of the furnace 2. The ammonia injected from the burners 4 burns, forming a flame F in the internal space 2b of the furnace 2. The furnace 2 is provided with an ignition device (not shown) that ignites the ammonia injected from the burners 4.

Fig. 2 is a schematic diagram showing a combustion device 10 according to this embodiment. As shown in Fig. 2, the combustion device 10 includes a burner 4, an ammonia tank 5, a first flow rate control valve 6, a second flow rate control valve 7, and a control device 8. Fig. 3 is a front view showing the burner 4 according to this embodiment. Specifically, Fig. 3 is a view of the burner 4 as seen from inside the furnace 2.

2 , the burner 4 is attached to the wall of the furnace 2 outside the furnace 2. The burner 4 has a first ammonia nozzle 41, a plurality of second ammonia nozzles 42, a nozzle case 43, a housing 44, an air flow path 45, and a swirler 46.

The first ammonia nozzle 41 and the multiple second ammonia nozzles 42 are nozzles that inject ammonia. The first ammonia nozzle 41 and the multiple second ammonia nozzles 42 have a substantially cylindrical shape. The first ammonia nozzle 41 and the multiple second ammonia nozzles 42 are housed in a nozzle case 43 while being held by the nozzle case 43. The nozzle case 43 has a substantially cylindrical shape. The first ammonia nozzle 41, the multiple second ammonia nozzles 42, and the nozzle case 43 extend in the same direction. Specifically, the first ammonia nozzle 41, the multiple second ammonia nozzles 42, and the nozzle case 43 extend in a direction intersecting (specifically, in a direction substantially perpendicular to) the wall of the furnace 2.

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

The circumferential direction surrounding the first ammonia nozzle 41 coincides with the circumferential direction of the nozzle case 43. Hereinafter, this direction will also be referred to as the circumferential direction of the burner 4. The extension direction of the central axis of the circumferential direction surrounding the first ammonia nozzle 41 coincides with the central axial direction of the nozzle case 43. Hereinafter, this direction will also be referred to as the central axial 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 case 43. Hereinafter, this direction will also be referred to as the radial direction of the burner 4.

A first injection port 41a is provided at the tip end of the first ammonia nozzle 41 (the end on the right side in FIG. 2 ). The first injection port 41a faces the internal space 2b of the furnace 2. The ammonia supplied to the first ammonia nozzle 41 is injected from the first injection port 41a into the internal 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 schematically shown by arrow A1 in FIG. 2 . As shown by arrow A1, the injection direction of ammonia from the first injection port 41a is the same as the central axis direction of the burner 4.

A second injection port 42a is provided at the tip end (the right end in FIG. 2 ) of each second ammonia nozzle 42. The second injection port 42a faces the internal space 2b of the furnace 2. The 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 in a direction inclined with respect to the central axis direction of the second ammonia nozzle 42. The flow of ammonia injected from the second injection port 42a is schematically shown by arrow A2 in FIGS. 2 and 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. In other words, the second injection port 42a faces in a direction inclined with respect to the circumferential direction of the burner 4 with respect to the central axis direction of the burner 4.

In other words, the second injection port 42a faces the tangential direction of the nozzle case 43 when viewed in the central axis direction of the burner 4. Therefore, the ammonia injected from the second injection port 42a flows toward the radially outward direction of the burner 4, parallel to the tangential direction of the nozzle case 43, as shown by arrow A2 when viewed in the central axis direction of the burner 4. As shown by arrow A2 in Fig. 2, the ammonia injected from the second injection port 42a flows toward the radially outward direction beyond the nozzle case 43 as it moves away from the second injection port 42a. In Fig. 2, an accurate illustration of the inclination of the second injection port 42a is omitted.

As shown in Fig. 2, 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 branches off and is 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 vaporized by a vaporizer (not shown). The vaporized ammonia is supplied to the first ammonia nozzle 41 and each second ammonia nozzle 42 through the flow path.

First flow rate adjustment valve 6 is provided in a portion of the flow path connected to ammonia tank 5 that is connected to first ammonia nozzle 41. First flow rate adjustment valve 6 adjusts the flow rate of ammonia supplied from ammonia tank 5 to first ammonia nozzle 41. The opening degree of first flow rate adjustment valve 6 is adjusted to adjust the flow rate of ammonia supplied from ammonia tank 5 to first ammonia nozzle 41. This adjusts the flow rate of ammonia sprayed from first injection port 41 a of first ammonia nozzle 41.

Second flow rate adjustment valve 7 is provided in a portion of the flow path connected to ammonia tank 5 that is connected to multiple second ammonia nozzles 42. Second flow rate adjustment valve 7 adjusts the flow rate of ammonia supplied from ammonia tank 5 to each second ammonia nozzle 42. The opening degree of second flow rate adjustment valve 7 is adjusted to adjust the flow rate of ammonia supplied from ammonia tank 5 to each second ammonia nozzle 42. This adjusts the flow rate of ammonia sprayed from second injection port 42a of second ammonia nozzle 42. However, second flow rate adjustment valve 7 may be provided for each second ammonia nozzle 42.

The housing 44 covers the tip end (the end on the right side in FIG. 2 ) of the outer circumferential surface of the nozzle case 43 and is connected to the wall of the furnace 2. The housing 44 has a generally truncated cone shape and is arranged coaxially with the nozzle case 43. An air flow path 45 is defined by the inner surface of the housing 44 and the outer circumferential surface of the nozzle case 43.

The air flow path 45 is arranged to cover the area between the tip of the nozzle case 43 (the right end in FIG. 2 ) and the furnace 2. In other words, the air flow path 45 is arranged around the multiple second ammonia nozzles 42. Air is supplied to the air flow path 45. An air injection port 45a is formed at the tip of the air flow path 45 (the right end in FIG. 2 ). The air injection port 45a faces the internal space 2b of the furnace 2. The air injection port 45a has an annular shape. The flow of air through the air flow path 45 is schematically shown by arrow A3 in FIG. 2 . As shown by arrow A3 in FIG. 2 , the air that has passed through the air flow path 45 is injected from the air injection port 45a into the internal space 2b of the furnace 2.

A swirler 46 is provided in the air flow path 45. The swirler 46 has swirling blades that impart a swirling force in the circumferential direction of the burner 4 to the air flowing through 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.

In the example of Fig. 2, an example in which there is one air path in the air flow path 45 is shown. However, the air flow path 45 may be partially divided, and the air path in the air flow path 45 may be branched. In the example of Fig. 2, the swirler 46 is installed at one location in the air flow direction in the air flow path 45. However, multiple swirlers 46 may be installed at intervals in the air flow direction in the air flow path 45.

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

4 is a diagram for explaining the combustion state in the combustion device 10 according to this embodiment. As described above, ammonia is injected from the burner 4 into the internal space 2b of the furnace 2. As a result, a flame F is formed in the internal space 2b of the furnace 2, as shown in FIG.

In the combustion device 10, 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. As a result, the ammonia injected from the second injection port 42a swirls together with the air and is effectively mixed with the air. Therefore, the ammonia injected from the second injection port 42a is quickly combusted.

In region R in Fig. 4, the ammonia injected from the second injection port 42a is effectively mixed with air. Region R is formed near the tip of the burner 4 and is located radially outward of the burner 4 with respect to the flame F. The flame F extends from inside region R into the furnace 2. In region R, the ratio of air to ammonia is locally low.

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

As shown in Fig. 4, when the flow rate of the ammonia injected from the second injection nozzle 42a is faster than the flow rate of the ammonia injected from the first injection nozzle 41a, the region R where the ratio of air to ammonia is locally low becomes larger compared to when the flow rate of the ammonia injected from the second injection nozzle 42a is slower than the flow rate of the ammonia injected from the first injection nozzle 41a. Furthermore, the faster flow rate of the ammonia injected from the second injection nozzle 42a promotes mixing with the combustion air. Therefore, stable combustion can be achieved while suppressing the generation of NOx.

In particular, in the combustion device 10, as shown in FIG. 3 , 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 inside the furnace 2. As a result, the ammonia injected from the second injection port 42a swirls together with the air and is more likely to be effectively mixed with the air. This improves the combustion stability of the ammonia and the shape stability of the flame F. However, the injection direction of ammonia from the second injection port 42a is not limited to the example shown in FIG. 3 . For example, the second injection port 42a may face the central axis direction of the second ammonia nozzle 42, and the injection direction of ammonia from the second injection port 42a may be the central axis direction of the burner 4. For example, the second injection port 42a does not have to face the tangential direction of the nozzle case 43 when viewed in the central axis direction of the burner 4, and may face radially inward or outward from the tangential direction.

In particular, in the combustion device 10, the multiple second ammonia nozzles 42 are arranged at intervals in the circumferential direction surrounding the first ammonia nozzle 41. Therefore, ammonia is injected from each of the multiple second injection ports 42a that are spaced apart from one another. As a result, the total contact area between the ammonia injected from the second injection port 42a and the air is larger than in a case where, for example, the second ammonia nozzle 42 is a single cylindrical nozzle that covers the first ammonia nozzle 41 and ammonia is injected from a single second injection port 42a. Therefore, the ammonia is more likely to be mixed effectively with the air. This improves the combustion stability of the ammonia and the shape stability of the flame F.

FIG. 5 is a diagram for explaining a combustion state according to a comparative example.

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

5, the flow rate of the ammonia injected from the second injection nozzle 42a is slower than the flow rate of the ammonia injected from the first injection nozzle 41a, which reduces the area R where the ratio of air to ammonia is locally low. Furthermore, the slow flow rate of the ammonia injected from the second injection nozzle 42a makes it difficult to promote mixing of the ammonia with the combustion air. Therefore, it may be difficult to achieve stable combustion while suppressing the generation of NOx.

As described above, the combustion device 10 includes at least one first ammonia nozzle 41 having a first injection port 41 a facing the inside of the furnace (in the above example, the internal space 2 b of the furnace 2), a plurality of second ammonia nozzles 42 having second injection ports 42 a facing the inside of the furnace and arranged at intervals in the circumferential direction around the at least one first ammonia nozzle 41 and surrounding the at least one first ammonia nozzle 41, an air flow path 45 that communicates with the inside of the furnace, is arranged 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 ammonia injected from the first injection port 41 a and the flow rate of ammonia injected from the second injection port 42 a so that the flow rate of ammonia injected from the second injection port 42 a is faster than the flow rate of ammonia injected from the first injection port 41 a. As a result, the flow rate of the ammonia injected from the second injection nozzle 42a is faster than the flow rate of the ammonia injected from the first injection nozzle 41a, and the region R where the ratio of air to ammonia is locally low becomes larger compared to when the flow rate of the ammonia injected from the second injection nozzle 42a is slower than the flow rate of the ammonia injected from the first injection nozzle 41a. Furthermore, the faster flow rate of the ammonia injected from the second injection nozzle 42a promotes mixing with the combustion air. Therefore, stable combustion can be achieved while suppressing the generation of NOx. As described above, the combustion device 10 can suppress the generation of NOx.

Furthermore, in the combustion device 10, ammonia is injected from each of the plurality of second injection ports 42a spaced apart from one another, thereby increasing the total contact area between the ammonia injected from the second injection ports 42a and the air. This makes it easier for the ammonia to mix effectively with the air. This improves the combustion stability of the ammonia and the shape stability of the flame F.

Fig. 6 is a schematic diagram showing a combustion apparatus 10A according to a first modified example. The combustion apparatus 10A differs from the above-described combustion apparatus 10 in that the burner 4 is replaced with a burner 4A. Fig. 7 is a front view showing the burner 4A according to the first modified example. Specifically, Fig. 7 is a view of the burner 4A as seen from inside the furnace 2.

As shown in Figures 6 and 7, the burner 4A differs from the burner 4 described above in that it has a plurality of first ammonia nozzles 41. Specifically, in the burner 4A, the plurality of first ammonia nozzles 41 are arranged at intervals in the circumferential direction of the burner 4A. In the example of Figure 7, the number of first ammonia nozzles 41 is four. However, the number of first ammonia nozzles 41 may be other than four. Also, in the example of Figure 7, the plurality of first ammonia nozzles 41 are arranged at equal intervals in the circumferential direction of the burner 4A. However, the plurality of first ammonia nozzles 41 may be arranged at unequal intervals in the circumferential direction of the burner 4A.

In the burner 4A, each first injection port 41a faces in 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 schematically shown by arrow A1 in Figures 6 and 7. As shown by arrow A1, the injection direction of ammonia from each first injection port 41a is a direction toward the central axis of the burner 4A when viewed from the internal space 2b of the furnace 2. In other words, each first injection port 41a faces the circumferential center of the burner 4A when viewed from the internal space 2b of the furnace 2.

As described above, in the first modified example, at least one first ammonia nozzle 41 includes a plurality of first ammonia nozzles 41 arranged at intervals in the circumferential direction (i.e., the circumferential direction of the burner 4A) in which a plurality of second ammonia nozzles 42 surround the at least one first ammonia nozzle 41, and the first injection port 41 a of each of the plurality of first ammonia nozzles 41 faces the center of the circumferential direction when viewed from inside the furnace (in the above example, the internal space 2 b of the furnace 2). As a result, by adjusting the flow rate of ammonia injected from each first injection port 41 a, it is possible to adjust the position in the central axis direction of the burner 4A where the ammonia injected from each first injection port 41 a joins and mixes. Therefore, it is possible to adjust the position in the central axis direction of the burner 4A where the ammonia injected from each first injection port 41 a joins and mixes, depending on the combustion state, such as the shape of the flame F in the combustion device 10A. This makes it possible to more appropriately improve the performance of suppressing the generation of NOx, the combustion stability of ammonia, and the shape stability of the flame F according to the combustion state in the combustion device 10A.

8 is a schematic diagram showing a combustion apparatus 10B according to a second modification. The combustion apparatus 10B differs from the combustion apparatus 10 described above in that the burner 4 is replaced with a burner 4B.

As shown by arrow A4 in Fig. 8 , burner 4B differs from the burner 4 described above in that the second ammonia nozzles 42 are rotatable about the central axis of the second ammonia nozzles 42. For example, the second ammonia nozzles 42 are rotatable by being supported by bearings (not shown). Burner 4B is provided with drive devices 47 that rotate the second ammonia nozzles 42. For example, the drive devices 47 are motors that rotate the second ammonia nozzles 42, and one drive device 47 is provided for each second ammonia nozzle 42. The control device 8 can rotate the second ammonia nozzles 42 by controlling the operation of the drive devices 47.

As described above, in the second modified example, the second ammonia nozzle 42 is provided so as to be rotatable about the central axis of the second ammonia nozzle 42. As described above, the second injection port 42a faces in a direction inclined with respect 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. Thus, the injection direction of ammonia from the second injection port 42a can be adjusted depending on the combustion state, such as the shape of the flame F, in the combustion device 10B. This makes it possible to more appropriately improve the performance of suppressing NOx generation, the combustion stability of ammonia, and the shape stability of the flame F depending on the combustion state in the combustion device 10B.

The combustion apparatus 10B according to the second modified example is an example in which the second ammonia nozzle 42 is made rotatable and a driving device 47 is added to the above-described combustion apparatus 10. However, the second ammonia nozzle 42 may be made rotatable and a driving device 47 may be added to the above-described combustion apparatus 10A according to the first modified example.

Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present disclosure.

For example, in the above description, the combustion devices 10, 10A, and 10B are provided in the furnace 2 of the boiler 1. However, the combustion devices 10, 10A, and 10B can be used in various furnaces of facilities other than the boiler 1.

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

For example, in the above description, the burners 4, 4A, and 4B inject ammonia as fuel. However, the burners 4, 4A, and 4B may inject pulverized coal as fuel in addition to ammonia.

The present disclosure can promote the use of ammonia, which leads to reduced CO2 emissions, and can therefore contribute, for example, to Sustainable Development Goal (SDG) 7 "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13 "Take urgent action to combat climate change and its impacts."

2: Furnace (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: Swirler

Claims (4)

at least one first ammonia nozzle having a first injection port facing the inside of the furnace;
a plurality of second ammonia nozzles each having a second injection port facing the inside of the furnace and arranged at intervals in a circumferential direction surrounding the at least one first ammonia nozzle around the at least one first ammonia nozzle;
an air flow path communicating with the inside of the furnace, disposed around the plurality of second ammonia nozzles, and provided with a swirler;
a control device that controls the flow rate of the ammonia injected from the first injection nozzle and the flow rate of the ammonia injected from the second injection nozzle so that the flow rate of the ammonia injected from the second injection nozzle is faster than the flow rate of the ammonia injected from the first injection nozzle, and so that a region where the ratio of air to ammonia is locally low is located around the flame formed in the furnace;
Equipped with
Combustion device. The injection direction of ammonia from the second injection port is the circumferential direction when viewed from inside the furnace.
The combustion device of claim 1 . the at least one first ammonia nozzle includes a plurality of first ammonia nozzles spaced apart in the circumferential direction;
the first injection port of each of the plurality of first ammonia nozzles faces a center in the circumferential direction when viewed from inside the furnace.
The combustion device according to claim 1 or 2. the second injection port faces in a direction inclined with respect to a central axis direction of the second ammonia nozzle,
the second ammonia nozzle is provided rotatably about the central axis ,
the control device adjusts the injection direction of the ammonia from the second injection port by rotating the second ammonia nozzle according to the combustion state in the combustion device.
The combustion device according to claim 1 or 2.