Combustion device and gas turbine

Abstract

A combustion device comprises a plurality of burners to which ammonia and second fuel are supplied, and a control device. The control device is configured such that in a first load region S1 including zero load, the control device supplies the second fuel to at least a first burner of the plurality of burners, and in a second load region in which the equivalence ratio ϕ of the first burner reaches a predetermined first value X1, the control device increases the ammonia flow rate R1 and reduces the second fuel flow rate R2 to the first burner so that the equivalence ratio ϕ of the total of ammonia and second fuel in the first burner is maintained at the first value X1, and supplies the second burner with the surplus second fuel not supplied to the first burner.

Description

Technical Field

[0001] The present disclosure relates to a combustion device and a gas turbine. This application claims the benefit of priority based on Japanese Patent Application No. 2022-28404 filed on February 25, 2022, the content of which is incorporated herein by reference.

Background Art

[0002] Conventionally, a combustion device using ammonia as fuel is known. The combustibility of ammonia is known to be poor. For example, Patent Document 1 discloses a gas turbine that uses ammonia together with other fuels to address this problem. In an operating region where the combustibility of ammonia is poor, this gas turbine increases the proportion of other fuels.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Combustion devices that use ammonia may use a two-stage combustion method. In such combustion devices, in the primary region, it is known that by burning ammonia at an equivalence ratio within a certain range, both NOx and unburned ammonia can be reduced while using ammonia as fuel. Note that the "equivalence ratio" is an index representing the fuel concentration in the air-fuel mixture, and is the value obtained by dividing the theoretical air-fuel ratio, which means the air-fuel ratio at which fuel and oxygen in the air-fuel mixture react without excess or deficiency, by the actual air-fuel ratio. However, in a combustion device, the air flow rate may generally be constant according to the opening area of the combustion device (for example, the area of openings such as air holes). Therefore, when the fuel flow rate varies according to the required load, the equivalence ratio of the fuel also varies. For this reason, in a certain load region, ammonia may not be burned at an equivalence ratio within the above range. In this case, it may not be possible to reduce both NOx and unburned ammonia.

[0005] An object of the present disclosure is to provide a combustion device and a gas turbine that can reduce both NOx and unburned ammonia while using ammonia as fuel in a wider load region.

Means for Solving the Problems

[0006] A combustion device according to one aspect of the present disclosure includes a plurality of burners each supplied with ammonia as a first fuel and a second fuel that does not contain N atoms and has better ignitability than ammonia, and a control device that adjusts the flow rate of ammonia and the flow rate of the second fuel to the plurality of burners. In a first load region including zero load, the second fuel is supplied to at least a first burner among the plurality of burners, and in a second load region where the equivalence ratio of the first burner reaches a predetermined first value, for the first burner, the flow rate of ammonia is increased and the flow rate of the second fuel is decreased so that the total equivalence ratio of ammonia and the second fuel in the first burner is maintained at the first value, and for the second burner, the surplus second fuel not supplied to the first burner is supplied. It is configured to include a control device.

[0007] In the third load region where the flow rate of ammonia to the first burner reaches a predetermined second value, the control device increases the flow rate of ammonia and decreases the flow rate of the second fuel so that the total equivalence ratio of ammonia and the second fuel in the second burner is maintained at the first value with respect to the second burner in which the equivalence ratio has reached the first value. It may be configured as described above.

[0008] Another aspect of the present disclosure is a gas turbine including the combustion device described above.

Advantages of the Invention

[0009] According to the present disclosure, both NOx and unburned ammonia can be reduced while using ammonia as fuel in a wider load region.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0011] Embodiments of the present disclosure will be described in detail with reference to the accompanying drawings below. The specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for ease of 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 denoted by the same reference numerals to omit redundant description, and elements not directly related to the present disclosure are not shown.

[0012] FIG. 1 is a schematic diagram showing a gas turbine 100 according to an embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 and is a schematic cross-sectional view showing a combustion device 1. Referring to FIG. 1, the gas turbine 100 includes a combustion device 1, a turbine 2, and a control device 90. The gas turbine 100 may further include other components. In other embodiments, the combustion device 1 may be used in other devices other than the gas turbine 100. For example, the combustion device 1 may be used in a device such as a jet engine or an industrial furnace.

[0013] In the present embodiment, the combustion device 1 uses a two-stage combustion method and includes a primary region Ar1 and a secondary region Ar2. As fuels, the combustion device 1 uses ammonia as a primary fuel and a second fuel that does not contain N atoms and has better ignitability than ammonia. The second fuel may be, for example, natural gas, hydrogen, kerosene, or a combination thereof. The second fuel is not limited to these and may be other fuels.

[0014] Referring to FIG. 2, the combustion device 1 includes a plurality of burners 11. In the present embodiment, the combustion device 1 includes four burners 11, that is, a first burner 11a, a second burner 11b, a third burner 11c, and a fourth burner 11d. However, the number of burners 11 is not limited to this and may be two, three, or five or more. For example, the plurality of burners 11 may be arranged in an arbitrary pattern such as an annular shape, a matrix shape, or a circular shape having substantially the same central axis.

[0015] Referring to FIG. 1, each burner 11 receives a supply of ammonia and a second fuel as fuel. Each burner 11 is connected to a pipe P1 configured to supply ammonia and a pipe P2 configured to supply the second fuel. Note that at least one of the plurality of burners 11, for example, the fourth burner 11d that does not actually use ammonia as described later, does not have to receive a supply of ammonia. In this case, the fourth burner 11d does not have to be connected to the pipe P1. In FIG. 1, the pipes P1 and P2 merge with each other, but the pipes P1 and P2 do not have to merge with each other and may be directly connected to the burner 11 respectively. Also, each burner 11 is connected to a pipe P3 configured to supply combustion air.

[0016] A valve V1 is provided in the pipe P1. The valve V1 may be communicably connected to the control device 90 by wire or wirelessly and may be controlled by the control device 90. The control device 90 adjusts the flow rate of ammonia to the burner 11 by controlling the opening degree of the valve V1.

[0017] A valve V2 is provided in the pipe P2. The valve V2 may be communicably connected to the control device 90 by wire or wirelessly and may be controlled by the control device 90. The control device 90 adjusts the flow rate of the second fuel to the burner 11 by controlling the opening degree of the valve V2.

[0018] As described above, in the present embodiment, the valves V1 and V2 function as adjustment means for adjusting the flow rates of ammonia and the second fuel to the plurality of burners 11. The adjustment means is controlled by the control device 90 so as to adjust the flow rates of ammonia and the second fuel to the plurality of burners 11. In other embodiments, the adjustment means may further include other components such as a flow meter or a pump. Also, in still other embodiments, the adjustment means does not have to include at least one of the plurality of valves V1 and the plurality of valves V2. For example, the adjustment means may include at least one valve.

[0019] A plurality of burners 11, specifically, a first burner 11a, a second burner 11b, and a third burner 11c that actually use ammonia as fuel, as will be described in detail later, are arranged to face the primary region Ar1 so as to supply ammonia and the second fuel to the primary region Ar1. The operation of the burner 11 will be described in detail later.

[0020] The combustion device 1 is connected to a plurality of pipes P4 for supplying dilution air to the secondary region Ar2. For example, the plurality of pipes P4 may be arranged along the circumferential direction of the combustion device 1. In other embodiments, instead of or in addition to the pipes P4, an opening for supplying dilution air to the secondary region Ar2 may be provided in the combustion device 1.

[0021] The fuel supplied to the combustion device 1 is burned in this order in the primary region Ar1 and the secondary region Ar2. The exhaust gas from the secondary region Ar2 is supplied to the turbine 2 and used for operations such as power generation.

[0022] The control device 90 controls the whole or a part of the gas turbine 100. The control device 90 includes components such as a processor 90a, a storage device 90b, and a connector 90c, and these components are connected to each other via a bus. For example, the processor 90a includes a CPU (Central Processing Unit) and the like. For example, the storage device 90b includes a hard disk, a ROM in which programs and the like are stored, and a RAM as a work area and the like. The control device 90 is communicably connected to each component of the gas turbine 100 via the connector 90c, either wired or wirelessly. For example, the control device 90 may further include other components such as a display device such as a liquid crystal display or a touch panel, and an input device such as a keyboard, a button, or a touch panel. For example, the operation of the control device 90 shown below may be realized by the processor 90a executing a program stored in the storage device 90b.

[0023] FIG. 3 is a graph showing an example of the transition of the air flow rate, fuel flow rate, and equivalence ratio with respect to the load in a gas turbine. In FIG. 3, the horizontal axis represents the load (%) in the turbine, the left vertical axis represents the air flow rate and the fuel flow rate, and the right vertical axis represents the equivalence ratio. Also, in FIG. 3, the solid line φ represents the equivalence ratio, the dashed line Rf represents the fuel flow rate, and the one-dot chain line Ra represents the air flow rate.

[0024] Generally, in a gas turbine using ammonia, in the primary region, by burning ammonia at an equivalence ratio φ within a certain range, for example, an equivalence ratio between 1.1 and 1.4, it is known that both NOx and unburned ammonia can be reduced while using ammonia as fuel. Also, by burning ammonia at the equivalence ratio within the above range, N2O having a high greenhouse effect can also be reduced. However, for example, when ammonia is burned at an equivalence ratio φ lower than the above range, NOx increases. Also, for example, when ammonia is burned at an equivalence ratio φ higher than the above range, both NOx and unburned ammonia increase. Note that the "equivalence ratio" is an index representing the fuel concentration in the air-fuel mixture, and is a value obtained by dividing the actual air-fuel ratio by the theoretical air-fuel ratio at which fuel and oxygen in the air-fuel mixture react without excess or deficiency. Also, in the present disclosure, when ammonia and a second fuel are used as fuel simultaneously, the "equivalence ratio" means the total equivalence ratio of ammonia and the second fuel.

[0025] However, as shown in FIG. 3, in a gas turbine, the air flow rate Ra may be generally constant depending on the opening area of the combustion device (for example, the area of the opening such as an air hole) regardless of the load. In this case, as shown in FIG. 3, when the fuel flow rate Rf varies according to the load, the equivalence ratio φ also varies.

[0026] Therefore, for example, when the combustion device is designed such that the equivalence ratio is between 1.1 and 1.4 in the high load region, in the low load region, the equivalence ratio may be lower than the above range. In this case, in the low load region, NOx increases. In contrast, when the combustion device is designed such that the equivalence ratio is between 1.1 and 1.4 in the low load region, in the high load region, the equivalence ratio may be higher than the above range. In this case, in the high load region, both NOx and unburned ammonia increase.

[0027] In this embodiment, in order to reduce both NOx and unburned ammonia while using ammonia as fuel in a wider load region, the flow rate of ammonia and the flow rate of the second fuel in the plurality of burners 11 are adjusted.

[0028] Subsequently, the specific operation of the burner 11 will be described.

[0029] FIG. 4 is a graph showing an example of the operation of each burner 11. As described above, in this embodiment, the combustion device 1 includes four burners 11. A, B, C, and D in FIG. 4 show the operations of the first burner 11a, the second burner 11b, the third burner 11c, and the fourth burner 11d, respectively. Further, E in FIG. 4 shows the operation of the plurality of burners 11 as a whole. In each of A, B, C, D, and E, the horizontal axis represents the load (%) in the gas turbine, the left vertical axis represents the flow rate of ammonia (NH3) and the flow rate of the second fuel, and the right vertical axis represents the equivalence ratio. In each of A, B, C, D, and E, the solid line φ represents the equivalence ratio, the dashed line R1 represents the flow rate of ammonia, and the dash-dotted line R2 represents the flow rate of the second fuel.

[0030] The load is divided into a plurality of load regions S1, S2, S3, S4. For example, the number of load regions may correspond to the number of burners 11. Therefore, in this embodiment, the load is divided into four load regions S1, S2, S3, S4.

[0031] For example, the first load region S1 is in the range of zero or more and less than L1. The load L1 is greater than zero. For example, as will be described later, the load L1 can be the load when the equivalence ratio φ in the first burner 11a reaches a predetermined first value X1.

[0032] The second load region S2 is in the range of L1 or more and less than L2. The load L2 is higher than the load L1. For example, as will be described later, the load L2 can be the load when the ammonia flow rate R1 in the first burner 11a reaches a predetermined second value X2.

[0033] The third load region S3 is in the range of L2 or more and less than L3. The load L3 is higher than the load L2 and less than 100. For example, as will be described later, the load L3 can be the load when the ammonia flow rate R1 in the second burner 11b reaches the second value X2.

[0034] The fourth load region S4 is in the range of L3 or more and 100 or less.

[0035] In the following description, each load region S1, S2, S3, S4 may also be simply referred to as "region". Further, in the following description, the equivalence ratio φ may be estimated based on the ammonia flow rate R1 and the second fuel flow rate R2 supplied to the burner 11 and the air flow rate supplied to the burner 11.

[0036] In the present embodiment, for better understanding, A in FIG. 4 is described as having R2 = 0 at a load of 0% and in the regions S3 and S4. However, even in these regions, a small amount of the second fuel may be used to maintain the pilot flame. Also, at a load of 0%, a small amount of the second fuel may be used to maintain the rotation of the turbine 2. The same applies to the regions where R2 = 0 in B, C, and D.

[0037] Referring to A in FIG. 4, in region S1, the processor 90a controls the adjustment means to supply the second fuel to the first burner 11a. For example, the processor 90a may control the adjustment means such that the flow rate R2 of the second fuel increases linearly with respect to the load. As the flow rate R2 of the second fuel increases, the equivalence ratio φ also increases. In region S1, ammonia is not supplied to the first burner 11a.

[0038] Referring to B, C, and D in FIG. 4, in region S1, ammonia and the second fuel are not supplied to the second burner 11b, the third burner 11c, and the fourth burner 11d. As described above, in region S1, a small amount of the second fuel may be used to maintain a pilot flame for the second burner 11b, the third burner 11c, and the fourth burner 11d. Similar explanations will be omitted hereinafter.

[0039] Referring to A in FIG. 4, at load L1, the equivalence ratio φ of the second fuel in the first burner 11a reaches a predetermined first value X1 (equivalence ratio φs of the second fuel = X1). In the first burner 11a, the air flow rate (e.g., the opening area) is defined such that the equivalence ratio φ of the second fuel reaches the first value X1 at load L1 with a predetermined amount of the second fuel. The first value X1 can be a value within a range capable of reducing both NOx and unburned ammonia when ammonia is burned, for example, a value between 1.1 and 1.4. That is, the first value X1 can also be said to be the optimum equivalence ratio. Therefore, in the first burner 11a, an environment is created in which ammonia can be burned while reducing both NOx and unburned ammonia from region S2 including load L1.

[0040] Therefore, in region S2, the processor 90a controls the adjustment means so as to increase the flow rate R1 of ammonia and decrease the flow rate R2 of the second fuel with respect to the first burner 11a such that the total equivalence ratio φ of ammonia and the second fuel is maintained at the first value X1 (equivalence ratio φa of ammonia + equivalence ratio φs of the second fuel = φconst (= X1)). For example, the processor 90a may control the adjustment means such that the flow rate R1 of ammonia increases linearly and the flow rate R2 of the second fuel decreases linearly with respect to the load.

[0041] Referring to B of FIG. 4, in region S2, the processor 90a controls the adjustment means so as to start supplying the surplus second fuel that cannot be supplied to the first burner 11a to the second burner 11b. For example, the processor 90a may control the adjustment means such that the flow rate R2 of the second fuel increases linearly with respect to the load.

[0042] Referring to C and D of FIG. 4, in region S2, ammonia and the second fuel are not supplied to the third burner 11c and the fourth burner 11d.

[0043] Referring to A of FIG. 4, at load L2, the flow rate R1 of ammonia in the first burner 11a reaches a predetermined second value X2. The second value X2 may be the maximum flow rate of ammonia that can be supplied to one burner 11, for example, a value at which the equivalence ratio φ reaches the first value X1 by ammonia (φa = X1). That is, the second value X2 can also be said to be the upper limit value of the ammonia supply flow rate to the burner 11. Therefore, in the first burner 11a, the flow rate R1 of ammonia can no longer be increased. Thus, from region S3 including load L2, the processor 90a controls the adjustment means so that in the first burner 11a, the flow rate R1 of ammonia is maintained at the second value X2 and the flow rate R2 of the second fuel is maintained at 0. When a small amount of the second fuel is used to maintain the pilot flame, that amount is maintained.

[0044] Referring to B in FIG. 4, at load L2, the equivalence ratio φ of the second fuel in the second burner 11b also reaches the first value X1. In the second burner 11b, the air flow rate (e.g., the opening area) is defined so that the equivalence ratio φ of the second fuel reaches the first value X1 at load L2 due to the amount of excess second fuel from the first burner 11a. Therefore, also in the second burner 11b, an environment is created in which ammonia can be burned while reducing both NOx and unburned ammonia from region S3 including load L2.

[0045] Note that in B of FIG. 4, at load L2, the equivalence ratio φ of the second fuel in the second burner 11b reaches the first value X1, but the processor 90a may control the adjusting means so that this equivalence ratio φ reaches the first value X1 at a load lower than load L2. Even in this case, in the second burner 11b, an environment is created in which ammonia can be burned while reducing both NOx and unburned ammonia from region S3.

[0046] Therefore, in region S3, the processor 90a controls the adjusting means to increase the flow rate R1 of ammonia and decrease the flow rate R2 of the second fuel so that the total equivalence ratio φ of ammonia and the second fuel is maintained at the first value X1 with respect to the second burner 11b. For example, the processor 90a may control the adjusting means so that the flow rate R1 of ammonia increases linearly and the flow rate R2 of the second fuel decreases linearly with respect to the load.

[0047] Referring to C in FIG. 4, in region S3, the processor 90a controls the adjusting means to start supplying the excess second fuel that cannot be supplied to the second burner 11b to the third burner 11c. For example, the processor 90a may control the adjusting means so that the flow rate R2 of the second fuel increases linearly with respect to the load.

[0048] Referring to D in FIG. 4, in region S3, ammonia and the second fuel are not supplied to the fourth burner 11d.

[0049] Referring to B in FIG. 4, at load L3, the ammonia flow rate R1 in the second burner 11b also reaches the second value X2. Therefore, in the second burner 11b, the ammonia flow rate R1 can no longer be increased. Thus, the processor 90a controls the adjustment means from the region S4 including the load L3 so that in the second burner 11b, the ammonia flow rate R1 is maintained at the second value X2 and the flow rate R2 of the second fuel is maintained at 0. When a small amount of the second fuel is used to maintain the pilot flame, that amount is maintained.

[0050] Referring to C in FIG. 4, at load L3, the equivalence ratio φ of the second fuel in the third burner 11c also reaches the first value X1. In the third burner 11c, the air flow rate (for example, the opening area) is defined so that the equivalence ratio φ of the second fuel reaches the first value X1 at load L3 depending on the amount of surplus second fuel from the second burner 11b. Therefore, also in the third burner 11c, an environment is created in which ammonia can be burned while reducing both NOx and unburned ammonia from the region S4 including the load L3.

[0051] Note that in C of FIG. 4, at load L3, the equivalence ratio φ of the second fuel in the third burner 11c reaches the first value X1, but the processor 90a may control the adjustment means so that this equivalence ratio φ reaches the first value X1 at a load lower than the load L3. Even in this case, in the third burner 11c, an environment is created in which ammonia can be burned while reducing both NOx and unburned ammonia from the region S4.

[0052] Therefore, the processor 90a controls the adjustment means so as to increase the ammonia flow rate R1 and decrease the flow rate R2 of the second fuel in the region S4 so that the total equivalence ratio φ of ammonia and the second fuel is maintained at the first value X1 for the third burner 11c. For example, the processor 90a may control the adjustment means so that the ammonia flow rate R1 increases linearly and the flow rate R2 of the second fuel decreases linearly with respect to the load.

[0053] Referring to D in FIG. 4, in region S4, the processor 90a controls the adjustment means to start supplying the surplus second fuel that cannot be supplied to the third burner 11c to the fourth burner 11d. For example, the processor 90a may control the adjustment means such that the flow rate R2 of the second fuel increases linearly with respect to the load.

[0054] Referring to E in FIG. 4, according to the above operation, when looking at the entire burner 11, the equivalence ratio φ increases linearly from a load of 0% to a load of 100%.

[0055] However, as shown in A of FIG. 4, when looking at a single first burner 11a, in regions S2, S3, S4 (R1>0) where ammonia is actually used, the equivalence ratio φ is maintained at a first value X1 that can reduce both NOx and unburned ammonia. Therefore, in a single first burner 11a, in regions S2, S3, S4 where ammonia is actually used, an increase in NOx caused by ammonia can be suppressed, and unburned ammonia can be reduced.

[0056] Similarly, as shown in B of FIG. 4, when looking at a single second burner 11b, in regions S3, S4 (R1>0) where ammonia is actually used, the equivalence ratio φ is maintained at the first value X1. Therefore, in a single second burner 11b, in regions S3, S4 where ammonia is actually used, an increase in NOx caused by ammonia can be suppressed, and unburned ammonia can be reduced.

[0057] Similarly, as shown in C of FIG. 4, when looking at a single third burner 11c, in region S4 (R1>0) where ammonia is actually used, the equivalence ratio φ is maintained at the first value X1. Therefore, in a single third burner 11c, in region S4 where ammonia is actually used, an increase in NOx caused by ammonia can be suppressed, and unburned ammonia can be reduced.

[0058] As described above, in each of the first burner 11a, the second burner 11b, and the third burner 11c, in the region where ammonia is actually used, an increase in NOx caused by ammonia can be suppressed, and unburned ammonia can be reduced. Therefore, also for the entire burner 11, in most of the load regions S2, S3, S4, ammonia can be used as fuel while reducing both NOx and unburned ammonia.

[0059] Note that, as shown by D in FIG. 4, in the fourth burner 11d, ammonia is not used as fuel. Also, in the fourth burner 11d, the equivalence ratio φ may reach the first value X1 or may not reach it.

[0060] As described above, the combustion device 1 of the gas turbine 100 according to the present embodiment includes a plurality of burners 11 each supplied with ammonia as a first fuel and a second fuel that does not contain N atoms and has better ignitability than ammonia, and a control device 90 that adjusts the flow rate R1 of ammonia and the flow rate R2 of the second fuel to the plurality of burners 11. Further, in the first load region S1 including zero load, the control device 90 supplies the second fuel to at least the first burner 11a among the plurality of burners 11, and in the second load region S2 where the equivalence ratio φ of the first burner 11a reaches a predetermined first value X1, for the first burner 11a, the flow rate R1 of ammonia is increased and the flow rate R2 of the second fuel is decreased so that the total equivalence ratio φ of ammonia and the second fuel in the first burner 11a is maintained at the first value X1, and surplus second fuel not supplied to the first burner 11a is supplied to the second burner 11b. With such a configuration, ammonia begins to be used from the burner 11 in which the equivalence ratio φ has reached the first value X1 within a range capable of reducing both NOx and unburned ammonia. Therefore, in the regions S2, S3, S4 after the load L1, both NOx and unburned ammonia can be reduced while using ammonia as fuel. Also, N2O having a high greenhouse effect can be reduced.

[0061] Further, in the combustion device 1, in the third load region S3 where the flow rate R1 of ammonia to the first burner 11a reaches a predetermined second value X2, for the second burner 11b where the equivalence ratio φ has reached the first value X1, the flow rate R1 of ammonia is increased and the flow rate R2 of the second fuel is decreased so that the total equivalence ratio φ of ammonia and the second fuel in the second burner 11b is maintained at the first value X1. According to such a configuration, the number of burners 11 using ammonia can be increased in response to an increase in the load.

[0062] As described above, the embodiments have been described with reference to the accompanying drawings, but the present disclosure is not limited to the above embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that those also belong to the technical scope of the present disclosure.

[0063] For example, in the above embodiment, in the first load region S1, the second fuel is not supplied to the second burner 11b, the third burner 11c, and the fourth burner 11d. However, in other embodiments, the second fuel may also be supplied to the second burner 11b, the third burner 11c, and the fourth burner 11d in the first load region S1. Note that when the second fuel is intensively supplied only to the first burner 11a in the first load region S1 as in the above embodiment, the equivalence ratio φ reaches the first value X1 at a lower load, so ammonia can be used from a lower load.

[0064] Since the present disclosure can promote the use of ammonia leading to a reduction in CO2 emissions, for example, it can contribute to Goal 7 of the Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy".

Description of reference numerals

[0065] 1 Combustion device 11 Burner 11a First burner 11b Second burner 90 Control device 100 Gas turbine R1 Ammonia flow rate R2 Second fuel flow rate S1 First load region S2 Second load region S3 Third load region X1 First value X2 Second value φ Equivalence ratio

Claims

1. A plurality of burners each supplied with ammonia as a first fuel and a second fuel that does not contain N atoms and has better ignitability than ammonia, A control device for adjusting the flow rate of ammonia and the flow rate of the second fuel to the plurality of burners, In a first load region including zero load, the second fuel is supplied to at least a first burner among the plurality of burners, In a second load region where the equivalence ratio of the first burner reaches a predetermined first value, for the first burner, the total equivalence ratio of ammonia and the second fuel in the first burner is maintained at the first value. As such, while increasing the flow rate of ammonia and decreasing the flow rate of the second fuel, for the second burner, surplus second fuel not supplied to the first burner is supplied. A control device configured as described above, A combustion device comprising the same.

2. The control device, In a third load region where the flow rate of ammonia to the first burner reaches a predetermined second value, for the second burner whose equivalence ratio has reached the first value, the total equivalence ratio of ammonia and the second fuel in the second burner is maintained at the first value. As such, while increasing the flow rate of ammonia and decreasing the flow rate of the second fuel. The combustion device according to claim 1, configured as described above.

3. A gas turbine comprising the combustion device according to claim 1 or 2.

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