WO2023062876A1

WO2023062876A1 - Combustion device and boiler

Info

Publication number: WO2023062876A1
Application number: PCT/JP2022/024360
Authority: WO
Inventors: 大樹石井; 亮花岡
Original assignee: 株式会社Ihi
Priority date: 2021-10-14
Filing date: 2022-06-17
Publication date: 2023-04-20
Also published as: AU2022367978B2; KR20240017097A; CN117795250A; JP7332060B1; AU2022367978A1; JPWO2023062876A1

Abstract

A combustion device (100) comprises: an ammonia injection nozzle (41) with an injection port (41c) facing the interior space of a furnace (2); a pulverized coal injection nozzle (43) with an injection port (43b) facing the interior space of the furnace (2); an adjustment mechanism (7) that adjusts the injection velocity of ammonia from the ammonia injection nozzle (41); and a control device (8) that controls the operation of the adjustment mechanism (7) so that the injection velocity of ammonia from the ammonia injection nozzle (41) is faster than the injection velocity of pulverized coal from the pulverized coal injection nozzle (43).

Description

Combustion equipment and boilers

The present disclosure relates to combustion equipment and boilers. This application claims the benefit of priority based on Japanese Patent Application No. 2021-169141 filed on October 14, 2021, the content of which is incorporated herein by reference.

Among burners installed in furnaces such as boilers, there are burners that have ammonia injection nozzles that inject ammonia as fuel. By using ammonia as a fuel, the amount of carbon dioxide emissions can be reduced. For example, Patent Literature 1 discloses a burner for co-firing pulverized coal and ammonia as fuel.

JP 2019-086189 A

In a burner that co-fires pulverized coal and ammonia as fuel, nitrogen oxides (hereinafter also referred to as NOx) are generated and reduced in the flame formed in front of the burner. Depending on the operating conditions, NOx may not be reduced sufficiently, resulting in an increase in NOx emissions. Therefore, new proposals for suppressing NOx emissions are desired.

An object of the present disclosure is to provide a combustion device and a boiler capable of suppressing nitrogen oxide (NOx) emissions.

In order to solve the above problems, the combustion apparatus of the present disclosure includes an ammonia injection nozzle whose injection port faces the interior space of the furnace, a pulverized coal injection nozzle whose injection port faces the interior space of the furnace, and ammonia from the ammonia injection nozzle. and a control device for controlling the operation of the adjustment mechanism so that the ammonia injection flow velocity from the ammonia injection nozzle is faster than the pulverized coal injection flow velocity from the pulverized coal injection nozzle. Prepare.

The adjustment mechanism may include a mechanism that adjusts the opening area of the injection port of the ammonia injection nozzle.

The ammonia injection nozzle is provided with a plurality of ammonia flow paths, and the adjustment mechanism may include a mechanism for adjusting the number of ammonia flow paths through which ammonia flows among the plurality of ammonia flow paths.

In order to solve the above problems, the boiler of the present disclosure includes the above combustion device.

According to the present disclosure, nitrogen oxide (NOx) emissions can be suppressed.

FIG. 1 is a schematic diagram showing a boiler according to this embodiment. FIG. 2 is a schematic diagram showing a combustion device according to this embodiment. FIG. 3 is a schematic diagram showing an adjusting mechanism according to this embodiment. FIG. 4 is a schematic diagram showing a state in which the opening area of the injection port of the ammonia injection nozzle according to this embodiment is smaller than in the example of FIG. FIG. 5 is a flow chart showing an example of the flow of processing performed by the control device according to the present embodiment. FIG. 6 is a diagram for explaining flames formed by the combustion apparatus according to this embodiment. FIG. 7 is a diagram for explaining flames formed by a combustion device according to a comparative example. FIG. 8 is a schematic diagram showing a combustion device according to a modification. FIG. 9 is a cross-sectional view showing the inside of an ammonia injection nozzle according to a modification.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present disclosure are omitted from the drawings. do.

FIG. 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 burners 4.

Furnace 2 is a furnace that burns fuel to generate combustion heat. The furnace 2 has a tubular shape such as a rectangular tubular shape extending in the vertical direction. In the furnace 2, high-temperature combustion gas is generated by burning fuel. The bottom of the furnace 2 is provided with an outlet 2a for discharging ash generated by combustion of 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. A 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. A horizontal flue 3 a extends horizontally from the top of the furnace 2 . A rear flue 3b extends downward from the end of the horizontal flue 3a.

The boiler 1 has a superheater (not shown) installed above the furnace 2 or the like. In the superheater, heat is exchanged between the combustion heat generated in the furnace 2 and water. Water vapor is thereby generated. The boiler 1 may also include various devices such as reheaters, economizers or air preheaters not shown in FIG.

The burner 4 is 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 spaced apart in the vertical direction, which is the extending direction of the furnace 2 . The burner 4 injects ammonia and pulverized coal as fuel into the furnace 2 . A flame F is formed in the furnace 2 by burning the fuel injected from the burner 4 . The furnace 2 is provided with an ignition device (not shown) that ignites the fuel injected from the burner 4.

FIG. 2 is a schematic diagram showing the combustion device 100 according to this embodiment. As shown in FIG. 2 , the combustion device 100 includes a burner 4 , an air supply section 5 , an ammonia tank 6 , an adjustment mechanism 7 and a control device 8 .

The burner 4 is attached to the wall of the furnace 2 outside the furnace 2 . The burner 4 has an ammonia injection nozzle 41 , an air injection nozzle 42 and a pulverized coal injection nozzle 43 . The ammonia injection nozzle 41 is a nozzle that injects ammonia. The air injection nozzle 42 is a nozzle that injects air for combustion. The pulverized coal injection nozzle 43 is a nozzle that injects pulverized coal.

The ammonia injection nozzle 41, the air injection nozzle 42 and the pulverized coal injection nozzle 43 have a cylindrical shape. The air injection nozzle 42 is arranged coaxially with the ammonia injection nozzle 41 so as to surround the ammonia injection nozzle 41 . The pulverized coal injection nozzle 43 is arranged coaxially with the air injection nozzle 42 so as to surround the air injection nozzle 42 . The ammonia injection nozzle 41, the air injection nozzle 42 and the pulverized coal injection nozzle 43 form a triple cylindrical structure. The central axes of the ammonia injection nozzle 41 , the air injection nozzle 42 and the pulverized coal injection nozzle 43 intersect the wall of the furnace 2 . Specifically, the central axes of the ammonia injection nozzle 41 , the air injection nozzle 42 and the pulverized coal injection nozzle 43 are substantially perpendicular to the wall of the furnace 2 .

Hereinafter, the radial direction of the burner 4, the axial direction of the burner 4, and the circumferential direction of the burner 4 are also simply referred to as the radial direction, the axial direction, and the circumferential direction. The furnace 2 side of the burner 4 (the right side in FIG. 2) is called the front end side, and the opposite side of the burner 4 to the furnace 2 side (the left side in FIG. 2) is called the rear end side.

The ammonia injection nozzle 41 includes a main body 41a, a supply port 41b, and an injection port 41c. The main body 41a has a cylindrical shape. The main body 41a extends on the central axis of the burner 4. As shown in FIG. The thickness, inner diameter and outer diameter of the main body 41a are substantially constant regardless of the position in the axial direction. However, the thickness, inner diameter and outer diameter of the main body 41a may change according to the axial position. A supply port 41b, which is an opening, is provided at the rear end of the main body 41a. The supply port 41 b is connected with the ammonia tank 6 . An injection port 41c, which is an opening, is provided at the tip of the main body 41a. The injection port 41 c faces the internal space of the furnace 2 . In other words, the injection port 41c faces the internal space of the furnace 2 .

Ammonia is supplied from the ammonia tank 6 into the main body 41a through the supply port 41b. As indicated by arrow A1, ammonia supplied into main body 41a flows through main body 41a. Ammonia passing through the main body 41a is injected toward the internal space of the furnace 2 from the injection port 41c. Thus, the ammonia injection nozzle 41 is provided toward the inner space of the furnace 2 .

Ammonia is stored in a liquid state in the ammonia tank 6 . Ammonia stored in the ammonia tank 6 is vaporized by a vaporizer. Vaporized ammonia is supplied to the ammonia injection nozzle 41 .

The air injection nozzle 42 includes a main body 42a and an injection port 42b. The main body 42a has a cylindrical shape. The main body 42a is arranged coaxially with the main body 41a of the ammonia injection nozzle 41 so as to surround the main body 41a. The main body 42a has a shape that tapers toward the distal end. A supply port (not shown) is provided in the rear portion of the main body 42a.

The supply port of the air injection nozzle 42 is connected to an air supply source (not shown). For example, the supply port of the air injection nozzle 42 is exposed to the atmosphere as an air supply source. An injection port 42b, which is an opening, is provided at the tip of the main body 42a. The tip of the main body 41a of the ammonia injection nozzle 41 is positioned radially inside the tip of the main body 42a. The injection port 42 b is an annular opening between the tip of the main body 42 a and the tip of the main body 41 a of the ammonia injection nozzle 41 . The injection port 42 b faces the internal space of the furnace 2 . In other words, the injection port 42b faces the internal space of the furnace 2 .

Air is supplied into the main body 42a from an air supply source through a supply port (not shown). The air supplied into the main body 42a flows through the space between the inner peripheral portion of the main body 42a and the outer peripheral portion of the main body 41a of the ammonia injection nozzle 41, as indicated by the arrow A2. The air that has passed through the main body 42a is injected toward the internal space of the furnace 2 from the injection port 42b. Thus, the air injection nozzle 42 is provided toward the interior space of the furnace 2 .

The pulverized coal injection nozzle 43 includes a main body 43a and an injection port 43b. The main body 43a has a cylindrical shape. The main body 43a is arranged coaxially with the main body 42a of the air injection nozzle 42 so as to surround the main body 42a. The main body 43a has a tapered shape toward the distal end. A supply port (not shown) is provided in the rear portion of the main body 43a.

The supply port of the pulverized coal injection nozzle 43 is connected to a pulverized coal supply source (not shown). An injection port 43b, which is an opening, is provided at the tip of the main body 43a. The axial position of the tip of the main body 43 a substantially coincides with the axial position of the tip of the main body 42 a of the air injection nozzle 42 . The injection port 43 b is an annular opening between the tip of the main body 43 a and the tip of the main body 42 a of the air injection nozzle 42 . The injection port 43 b faces the internal space of the furnace 2 . In other words, the injection port 43b faces the internal space of the furnace 2 .

Pulverized coal is supplied from a pulverized coal supply source into the main body 43a through a supply port (not shown) together with air for transporting the pulverized coal. As indicated by an arrow A3, the pulverized coal supplied into the main body 43a flows together with the air in the space between the inner peripheral portion of the main body 43a and the outer peripheral portion of the main body 42a of the air injection nozzle . The pulverized coal that has passed through the main body 43a is injected toward the internal space of the furnace 2 from the injection port 43b. Thus, the pulverized coal injection nozzle 43 is provided toward the interior space of the furnace 2 .

The air supply unit 5 supplies combustion air to the flame F formed by the burner 4 from the outside in the radial direction. The air supply unit 5 is arranged so as to cover the space between the tip of the burner 4 and the furnace 2 . A flow path 51 through which air flows is formed in the air supply portion 5 . The channel 51 is formed in a cylindrical shape coaxial with the burner 4 . The flow path 51 is connected to an air supply source (not shown). An injection port 52 is formed at the end of the flow path 51 on the furnace 2 side.

As indicated by arrow A4, the air supplied from the air supply source to the air supply unit 5 passes through the flow path 51 and is injected from the injection port 52 toward the internal space of the furnace 2. The injection port 52 faces the internal space of the furnace 2 . That is, the injection port 52 faces the internal space of the furnace 2 . Thus, the air supply unit 5 is provided toward the inner space of the furnace 2 . The air injected from the injection port 52 of the air supply unit 5 advances toward the inner space of the furnace 2 while swirling in the circumferential direction.

The adjustment mechanism 7 is a mechanism for adjusting the injection flow rate of ammonia from the ammonia injection nozzle 41 . The injection flow velocity of ammonia is the flow velocity of ammonia injected from the injection port 41 c of the ammonia injection nozzle 41 . In this embodiment, the adjustment mechanism 7 adjusts the injection flow rate of ammonia from the ammonia injection nozzle 41 by adjusting the opening area of the injection port 41 c of the ammonia injection nozzle 41 . Details of the adjustment mechanism 7 will be described with reference to FIG.

FIG. 3 is a schematic diagram showing the adjusting mechanism 7 according to this embodiment. As shown in FIG. 3, the tip of the ammonia injection nozzle 41 is provided with a variable portion 41d. As the variable portion 41d deforms, the opening area of the injection port 41c changes. For example, the variable portion 41d includes a plurality of members spaced apart in the circumferential direction, and can be deformed so as to assume an inclined posture in which the tip of each member is positioned radially inward from the rear end. As such a variable part 41d, for example, a structure similar to that of a convergence divergence nozzle can be adopted.

The adjustment mechanism 7 has a driving device 71 . The driving device 71 deforms the variable portion 41 d of the ammonia injection nozzle 41 . For example, the driving device 71 is provided at the rear end of the variable portion 41d and includes a power source such as a motor that generates power. The driving device 71 can change the posture of the variable portion 41d by rotating the variable portion 41d around the rear end of the variable portion 41d. The adjustment mechanism 7 can adjust the opening area of the injection port 41 c of the ammonia injection nozzle 41 by deforming the variable portion 41 d of the ammonia injection nozzle 41 with the driving device 71 .

FIG. 4 is a schematic diagram showing a state in which the opening area of the injection port 41c of the ammonia injection nozzle 41 according to this embodiment is smaller than in the example of FIG. In the example of FIG. 4, compared with the example of FIG. 3, the variable portion 41d is deformed such that the radial position of the tip of the variable portion 41d moves radially inward. Thereby, the shape of the variable portion 41d is tapered toward the distal end side. For example, the variable portion 41d in FIG. 4 has a truncated cone shape. Therefore, the opening area of the injection port 41c of the ammonia injection nozzle 41 is reduced.

The smaller the opening area of the injection port 41c of the ammonia injection nozzle 41, the faster the flow rate of ammonia injected from the injection port 41c. Therefore, the adjustment mechanism 7 can adjust the injection flow rate of ammonia from the ammonia injection nozzle 41 by adjusting the opening area of the injection port 41 c of the ammonia injection nozzle 41 . Thus, according to the adjustment mechanism 7, the injection flow rate of ammonia is properly adjusted.

The control device 8 in FIG. 2 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 combustion device 100 as a whole. In particular, controller 8 controls the operation of adjustment mechanism 7 . Specifically, the control device 8 controls the driving device 71 of the adjusting mechanism 7 to adjust the opening area of the injection port 41c of the ammonia injection nozzle 41, thereby adjusting the injection flow rate of ammonia from the ammonia injection nozzle 41. can do.

FIG. 5 is a flowchart showing an example of the flow of processing performed by the control device 8 according to this embodiment. The processing flow shown in FIG. 5 is, for example, repeatedly executed at preset time intervals. As will be described later, the processing example of FIG. 5 is merely an example, and the processing performed by the control device 8 is not limited to this example.

When the process flow shown in FIG. 5 starts, in step S101, the control device 8 acquires the injection flow rate of pulverized coal from the pulverized coal injection nozzle 43. The injection flow velocity of pulverized coal is the flow velocity of pulverized coal injected from the injection port 43 b of the pulverized coal injection nozzle 43 .

The amount of carrier air supplied to the pulverized coal injection nozzle 43 changes according to the required combustion amount in the furnace 2 . As a result, the pulverized coal injection flow rate changes according to the required combustion amount in the furnace 2 . For example, the injection flow velocity of pulverized coal increases as the required combustion amount in the furnace 2 increases. The required combustion amount in the furnace 2 has a correlation with the required load of the boiler 1 or the required power generation amount.

For example, the control device 8 acquires the supply amount of air for transportation from a device that controls the supply amount of air for transportation supplied to the pulverized coal injection nozzle 43 . Then, the control device 8 can acquire the jet flow velocity of the pulverized coal based on the supply amount of air for transportation. The controller 8 may control the amount of carrier air supplied to the pulverized coal injection nozzle 43 .

After step S101, in step S102, the control device 8 controls the adjustment mechanism 7 so that the injection flow rate of ammonia is faster than the injection flow rate of pulverized coal. For example, the control device 8 controls the driving device 71 of the adjustment mechanism 7 so that the opening area of the injection port 41c of the ammonia injection nozzle 41 changes according to the injection flow rate of pulverized coal. Thereby, the injection flow velocity of ammonia can be made faster than the injection flow velocity of pulverized coal.

It is preferable that the control device 8 controls the adjustment mechanism 7 in consideration of parameters other than the opening area of the injection port 41c among the parameters that affect the injection flow rate of ammonia. For example, the amount of ammonia supplied to the ammonia injection nozzle 41 can change according to the required combustion amount in the furnace 2 . Therefore, the control device 8 preferably controls the adjustment mechanism 7 based on the amount of ammonia supplied to the ammonia injection nozzle 41 in addition to the pulverized coal injection flow rate. As a result, the injection flow velocity of ammonia is more appropriately achieved to be faster than the injection flow velocity of pulverized coal.

In the above, an example was explained in which the opening area of the injection port 41c of the ammonia injection nozzle 41 is changed according to the injection flow velocity of pulverized coal. However, the control device 8 may change the opening area of the injection port 41c of the ammonia injection nozzle 41 according to parameters other than the injection flow velocity of pulverized coal. For example, the control device 8 may change the opening area of the injection port 41 c of the ammonia injection nozzle 41 according to the required combustion amount in the furnace 2 , the required load of the boiler 1 , or the required power generation amount of the boiler 1 .

As described above, in the combustion device 100 according to the present embodiment, the control device 8 controls the injection flow rate of ammonia from the ammonia injection nozzle 41 to be faster than the injection flow rate of pulverized coal from the pulverized coal injection nozzle 43. It controls the operation of the adjustment mechanism 7 . The shape of the flame F formed in front of the burner 4 and the phenomenon occurring within the flame F differ depending on the magnitude relationship between the injection flow velocity of ammonia and the injection flow velocity of pulverized coal. The shape of the flame F and phenomena occurring within the flame F will be described below with reference to FIGS. 6 and 7. FIG.

FIG. 6 is a diagram for explaining the flame F formed by the combustion device 100 according to this embodiment. That is, the flame F shown in FIG. 6 is a flame when the injection flow velocity of ammonia is faster than the injection flow velocity of pulverized coal.

In the example of FIG. 6, the flame F has an elongated shape extending on the central axis of the burner 4. In the vicinity of the surface layer of the flame F, a flow of air injected from the air supply section 5 is formed as indicated by the dashed arrow A5. The pulverized coal injected from the pulverized coal injection nozzle 43 is pulled by the flow of air injected from the air supply unit 5 and flows near the surface layer of the flame F. Therefore, the pulverized coal injected from the pulverized coal injection nozzle 43 flows in the vicinity of the surface layer of the flame F, as indicated by the dashed arrow A6, along the air flow indicated by the dashed arrow A5. As a result, the pulverized coal is burned in the region R1 near the surface layer of the flame F, and NOx is generated. A region R1 is a pulverized coal combustion region.

In the example of FIG. 6, the injection flow velocity of ammonia is higher than the injection flow velocity of pulverized coal. Therefore, the ammonia injected from the ammonia injection nozzle 41 is less likely to be pulled by the flow of air injected from the air supply section 5, so it flows in the axial direction of the burner 4 through the center of the flame F as indicated by the solid line arrow A7. . The direction of flow of ammonia can actually take various directions, but the main direction is the axial direction of the burner 4 . As a result, ammonia (NH ₃ ) is decomposed into NH ₂ , NH, and N in the oxygen-poor region R2 on the center side of the flame F. The region R2 is positioned radially inward with respect to the region R1. Region R2 is the decomposition region of ammonia. Region R2 has an elongated shape extending on the central axis of burner 4 .

Then, in the region R3 on the tip side of the flame F, NOx is reduced by NH ₂ , NH, and N. The region R3 is located on the front side with respect to the region R2. Region R3 is a NOx reduction region.

FIG. 7 is a diagram for explaining the flame F formed by the combustion device according to the comparative example. In the comparative example, unlike the present embodiment, the injection flow velocity of ammonia is slower than the injection flow velocity of pulverized coal. That is, the flame F shown in FIG. 7 is a flame when the injection flow velocity of ammonia is slower than the injection flow velocity of pulverized coal.

In the example of FIG. 7, the flame F has a radially expanded shape compared to the example of FIG. As in the example of FIG. 6, as indicated by dashed arrows A5 and A6, the air injected from the air supply unit 5 and the pulverized coal injected from the pulverized coal injection nozzle 43 are near the surface of the flame F. flowing. In a region R1 near the surface layer of the flame F, pulverized coal is burned to generate NOx.

In the example of FIG. 7, the injection flow velocity of ammonia is slower than the injection flow velocity of pulverized coal. Therefore, ammonia injected from the ammonia injection nozzle 41 is likely to be pulled by the flow of air injected from the air supply section 5 . Therefore, most of the ammonia injected from the ammonia injection nozzle 41 flows along the air flow indicated by the dashed arrow A5, as indicated by the solid arrow A7. As a result, in the oxygen-rich region R4 away from the center of the flame F to the surface layer side, ammonia burns and NOx is generated. Region R4 is the ammonia combustion region.

Part of the ammonia injected from the ammonia injection nozzle 41 is decomposed into NH ₂ , NH, and N on the center side of the flame F where oxygen is scarce. Then, in the region R3 on the tip side of the flame F, NOx is reduced by NH ₂ , NH, and N.

In the comparative example shown in FIG. 7, unlike the example in FIG. 6, most of the ammonia injected from the ammonia injection nozzle 41 is burned to generate NOx. Therefore, in addition to NOx generated by combustion of pulverized coal, combustion of ammonia also generates NOx. Therefore, the amount of NOx generated increases. Also, most of the ammonia injected from the ammonia injection nozzle 41 is combusted and is not decomposed. Therefore, the amounts of NH ₂ , NH, and N produced by decomposition of ammonia are reduced. Therefore, reduction of NOx is not sufficiently performed, and the amount of NOx emissions increases.

As described above, in the present embodiment, the control device 8 controls the adjustment mechanism 7 so that the injection flow rate of ammonia from the ammonia injection nozzle 41 is faster than the injection flow rate of pulverized coal from the pulverized coal injection nozzle 43. control behavior. Thereby, as in the example of FIG. 6, the ammonia injected from the ammonia injection nozzle 41 can be sent to the oxygen-poor region R2 on the center side of the flame F and decomposed. Therefore, the generation of NOx due to combustion of ammonia is suppressed, and the decomposition of ammonia is promoted. Therefore, NOx is effectively reduced, and NOx emissions are suppressed.

If the injection flow velocity of ammonia from the ammonia injection nozzle 41 becomes excessively faster than the injection flow velocity of pulverized coal from the pulverized coal injection nozzle 43, the shape of the flame F formed in front of the burner 4, and within the flame F The phenomenon that occurs may deviate from the example of FIG. For example, it is conceivable that the ammonia injected from the ammonia injection nozzle 41 reaches the front of the region R2, which is the ammonia decomposition region, in a state where it is not sufficiently decomposed. In this case, the amounts of NH ₂ , NH, and N produced by decomposition of ammonia are reduced, and the effect of suppressing NOx emissions may be reduced. Therefore, the control device 8 operates the adjustment mechanism 7 so that the injection flow rate of ammonia from the ammonia injection nozzle 41 is faster than the injection flow rate of pulverized coal from the pulverized coal injection nozzle 43 and is equal to or lower than the upper limit speed. is preferably controlled. The upper limit speed is, for example, a speed that is faster than the injection flow speed of pulverized coal by a predetermined ratio.

Furthermore, in this embodiment, as in the example of FIG. 6, the flame F formed by the combustion device 100 has an elongated shape. As a result, the time for the pulverized coal to come into contact with oxygen is lengthened, thus promoting the combustion of the pulverized coal. Therefore, generation and discharge of unburned fuel are suppressed.

FIG. 8 is a schematic diagram showing a combustion device 100A according to a modification. As shown in FIG. 8, a combustion device 100A is an example in which the adjustment mechanism 7 in the combustion device 100 described above is replaced with an adjustment mechanism 7A.

The ammonia injection nozzle 41A of the combustion device 100A has a different internal structure compared to the ammonia injection nozzle 41 of the combustion device 100 described above. FIG. 9 is a cross-sectional view showing the inside of an ammonia injection nozzle 41A according to a modification. Specifically, FIG. 9 is a cross-sectional view taken along line XX in FIG. 8 orthogonal to the central axis of the ammonia injection nozzle 41A.

As shown in FIG. 9, a plurality of supply pipes 41e are provided inside the main body 41a of the ammonia injection nozzle 41A. In the example of FIG. 9, there are six supply pipes 41e. However, the number of supply pipes 41e may be other than six. The supply pipe 41e has a tubular shape such as a cylindrical shape. The supply pipe 41e extends in the axial direction of the main body 41a. In the example of FIG. 9, the supply pipes 41e are arranged at regular intervals in the circumferential direction of the main body 41a. However, the arrangement of the supply pipes 41e inside the main body 41a is not limited to the example in FIG. Ammonia supplied from the ammonia tank 6 into the main body 41a passes through the ammonia flow path 41f, which is the internal space of each supply pipe 41e, and is injected from the injection port 41c. Thus, the ammonia injection nozzle 41 is provided with a plurality of ammonia flow paths 41f.

The adjustment mechanism 7A in FIG. 8 adjusts the injection flow rate of ammonia from the ammonia injection nozzle 41A by adjusting the number of ammonia flow paths 41f through which ammonia flows among the plurality of ammonia flow paths 41f.

Specifically, the adjustment mechanism 7A has a switching valve 71A. 71 A of switching valves are provided in the flow path which connects the ammonia tank 6 and the ammonia injection nozzle 41A. The switching valve 71A switches between a state in which ammonia is supplied from the ammonia tank 6 and a state in which ammonia is not supplied from the ammonia tank 6 for each supply pipe 41e. In other words, the switching valve 71A switches the supply pipe 41e to which ammonia is supplied among the plurality of supply pipes 41e. Thereby, the number of ammonia flow paths 41f through which ammonia flows is adjusted among the plurality of ammonia flow paths 41f.

Among the plurality of ammonia flow paths 41f, the smaller the number of ammonia flow paths 41f through which ammonia flows, the smaller the total cross-sectional area of the ammonia injection nozzle 41. Therefore, the flow velocity of ammonia injected from the injection port 41c becomes faster. For example, when ammonia flows through only some of the ammonia flow channels 41f among the plurality of ammonia flow channels 41f, compared to the case where ammonia flows through all of the ammonia flow channels 41f, the amount of ammonia injected from the injection port 41c increases. flow velocity increases. Therefore, the adjustment mechanism 7A can adjust the injection flow rate of ammonia from the ammonia injection nozzle 41A by adjusting the number of ammonia flow paths 41f through which ammonia flows among the plurality of ammonia flow paths 41f. Thus, according to the adjustment mechanism 7A, the injection flow rate of ammonia is properly adjusted.

In the combustion device 100A, similarly to the combustion device 100 described above, the control device 8 controls the adjustment mechanism 7A so that the injection flow velocity of ammonia is faster than the injection flow velocity of pulverized coal. For example, the control device 8 controls the switching valve 71A of the adjusting mechanism 7A so that the number of the ammonia flow paths 41f through which ammonia flows changes according to the injection flow rate of pulverized coal. Thereby, the injection flow velocity of ammonia can be made faster than the injection flow velocity of pulverized coal. Therefore, as with the combustion device 100 described above, NOx emissions are suppressed. In addition, generation and discharge of unburned fuel are suppressed.

The control device 8 may change the number of ammonia flow paths 41f through which ammonia flows according to parameters other than the injection flow rate of pulverized coal. For example, the control device 8 may change the number of ammonia flow paths 41f through which ammonia flows according to the required combustion amount in the furnace 2, the required load of the boiler 1, or the required power generation amount of the boiler 1.

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 or modifications within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. be done.

The adjustment mechanism 7 and the adjustment mechanism 7A have been described above as examples of the adjustment mechanism that adjusts the injection flow rate of ammonia from the ammonia injection nozzle 41 . However, any mechanism other than the adjusting mechanism 7 and the adjusting mechanism 7A may be used as long as it has a function of adjusting the injection flow rate of ammonia from the ammonia injection nozzle 41 . In addition, the adjustment mechanism 7 for adjusting the opening area of the injection port 41c of the ammonia injection nozzle 41 and the adjustment mechanism 7A for adjusting the number of the ammonia passages 41f among the plurality of ammonia passages 41f through which ammonia flows are used together. may

An example in which the

combustion devices

100 and 100A are provided in the furnace 2 of the boiler 1 has been described above. However, the furnace in which the

combustion devices

100 and 100A are used may be any furnace that burns fuel to generate combustion heat.

Combustion devices

100 and 100A can be used in various furnaces of equipment other than boiler 1 .

The present disclosure contributes to stabilization of combustion by combustion equipment used in boilers and the like, and reduction of repair frequency of combustion equipment. Ensure access to affordable and modern energy” and Goal 13 “Take urgent action to combat climate change and its impacts”.

1: Boiler 2: Furnace 7: Adjustment mechanism 7A: Adjustment mechanism 8: Control device 41: Ammonia injection nozzle 41A: Ammonia injection nozzle 41c: Injection port 41f: Ammonia flow path 43: Pulverized coal injection nozzle 43b: Injection port 100: Combustion Device 100A: Combustion device

Claims

an ammonia injection nozzle whose injection port faces the interior space of the furnace;
a pulverized coal injection nozzle having an injection port facing the internal space of the furnace;
an adjustment mechanism for adjusting the injection flow rate of ammonia from the ammonia injection nozzle;
a controller for controlling the operation of the adjustment mechanism so that the injection flow rate of ammonia from the ammonia injection nozzle is faster than the injection flow rate of pulverized coal from the pulverized coal injection nozzle;
comprising
Combustion device.
The adjustment mechanism includes a mechanism for adjusting the opening area of the injection port of the ammonia injection nozzle,
Combustion device according to claim 1 .
The ammonia injection nozzle is provided with a plurality of ammonia flow paths,
The adjustment mechanism includes a mechanism for adjusting the number of the ammonia channels through which ammonia flows among the plurality of ammonia channels,
Combustion device according to claim 1 or 2.
A boiler comprising the combustion device according to any one of claims 1 to 3.