Combustion system

Abstract

This combustion system comprises one or more burners (11), a sensor that measures the concentration of a prescribed component in a gas, and a control device. Each burner (11) includes: a first opening (O1) that supplies a first fuel (F1) containing nitrogen; a second opening (O2) which is disposed in a region radially outward of the first opening (O1) and which supplies one of either air (A) or a premixed gas; and a third opening (O3) which is disposed in a region radially outward of the second opening (O2) and which supplies the other of either air (A) or the premixed gas. The premixed gas includes: a second fuel (F2) containing nitrogen; and air (A). The control device controls at least one of the one or more burners (11) on the basis of a measurement value from the sensor to adjust at least one of the following: the amount of the first fuel (F1) to be supplied from the first opening (O1); the amount of the second fuel (F2) in the premixed gas; the amount of air (A) in the premixed gas; and the amount of the air (A) to be supplied from the second opening (O2) or the third opening (O3).

Description

Combustion System

[0001] This application claims the benefit of priority from Japanese Patent Application No. 2024-113774, filed on July 17, 2024, the contents of which are incorporated herein by reference.

[0002] Burners may use fuels containing nitrogen, such as ammonia. For example, Patent Document 1 discloses multiple burners that use ammonia as fuel. In each burner, ammonia is injected from a central injection hole. A portion of the combustion air and ammonia premixed fuel are injected from outer openings of the injection hole. The remaining combustion air flows further outside the premixed fuel. The ammonia, premixed fuel, and remaining combustion air are combusted in a combustion field. Because a portion of the combustion air is used for premixing, the contact area between the premixed fuel and the combustion air in the combustion field is smaller than in diffusion combustion, which does not use premixed fuel. Furthermore, the local air ratio in this contact area is lower than in diffusion combustion. This configuration reduces NOx emissions compared to diffusion combustion. Patent Document 1 also discloses a temperature sensor that detects the metal temperature of the burner. If the metal temperature detected by the temperature sensor exceeds a threshold, the injection amount from the outer injection nozzle is increased.

[0003] JP 2023-94301 A

[0004] When nitrogen-containing fuel is burned, NOx is generated. The amount of NOx can vary depending on various factors. For example, in Patent Document 1, depending on various factors, the local air ratio at the contact area can vary, which can lead to an increase in NOx.

[0005] The present disclosure aims to provide a combustion system that can reduce NOx when nitrogen-containing fuel is used.

[0006] A combustion system according to one aspect of the present disclosure comprises one or more burners facing a combustion space, each of the one or more burners including: a first opening that supplies a first fuel containing nitrogen to the combustion space; a second opening that is arranged in a region radially outward of the first opening and supplies one of air and a premixed gas to the combustion space, the premixed gas including a second fuel containing nitrogen and air; and a third opening that is arranged in a region radially outward of the second opening and supplies the other of the air and the premixed gas to the combustion space; a sensor that measures the concentration of a predetermined component in the gas; and a control device that controls at least one of the one or more burners based on the measurement value of the sensor to adjust at least one of the amount of the first fuel supplied from the first opening, the amount of the second fuel in the premixed gas, the amount of air in the premixed gas, and the amount of air supplied from the second opening or the third opening.

[0007] Each of the first fuel and the second fuel may include ammonia.

[0008] The sensor may include a first sensor that measures the NOx concentration in the exhaust gas from the combustion space, and the control device may adjust at least one of the amount of the first fuel supplied from the first opening and the amount of the second fuel in the premixed gas based on the measurement value of the first sensor.

[0009] The sensor may include a second sensor that measures the oxygen concentration in the exhaust gas from the combustion space, and the control device may adjust at least one of the amount of air in the premixed gas and the amount of air supplied from the second opening or the third opening based on the measurement value of the second sensor.

[0010] The sensor may include a third sensor that measures the concentration of the second fuel in the premixed gas, and the control device may adjust at least one of the amount of the second fuel and the amount of air in the premixed gas based on the measurement value of the third sensor.

[0011] The sensor may include a fourth sensor that measures the oxygen concentration in the premixed gas, and the control device may adjust at least one of the amount of the second fuel and the amount of air in the premixed gas based on the measurement value of the fourth sensor.

[0012] Each of the one or more burners may include a fourth opening arranged in a region radially outward from the first opening and radially inward from the second opening, for supplying a third fuel having higher combustibility than the first fuel to the combustion space.

[0013] The one or more burners may include a plurality of burners arranged on the wall at a distance from each other along a predetermined horizontal direction, the first sensor may include at least two sensors capable of measuring NOx concentration arranged at a distance from each other along the predetermined horizontal direction, and the control device may control at least one of the plurality of burners based on the measurement values ​​of the at least two sensors to adjust at least one of the amount of the first fuel supplied from the first opening and the amount of the second fuel in the premixed gas.

[0014] The one or more burners may include a plurality of burners arranged on the wall at a distance from each other along a predetermined horizontal direction, the second sensor may include at least two sensors capable of measuring oxygen concentration arranged at a distance from each other along the predetermined horizontal direction, and the control device may control at least one of the plurality of burners based on the measurement values ​​of the at least two sensors to adjust at least one of the amount of air in the premixed gas and the amount of air supplied from the second opening or the third opening.

[0015] The second opening may supply premixed gas to the combustion space, and the third opening may supply air to the combustion space.

[0016] The second opening may supply air to the combustion space and the third opening may supply premixed gas to the combustion space.

[0017] According to the present disclosure, NOx can be reduced when a fuel containing nitrogen is used.

[0018] 1 is a schematic cross-sectional view of a combustion system according to an embodiment, FIG 2 is a schematic diagram of a burner, and FIG 3 is a schematic diagram of a burner according to another embodiment.

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. 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.

[0020] 1 is a schematic diagram of a combustion system 100 according to an embodiment. In this embodiment, the combustion system 100 is applied to a boiler 50. In other embodiments, the combustion system 100 may be applied to other equipment. For example, the combustion system 100 includes the boiler 50 and a control device 90. The combustion system 100 may further include other components.

[0021] The boiler 50 includes a furnace 1 .

[0022] The furnace 1 extends in the vertical direction. In this embodiment, the furnace 1 has a rectangular shape when viewed from above. In this embodiment, the furnace 1 includes four side walls, including a front wall 1F, a rear wall 1R, a right wall, and a left wall. Each of the side walls extends in the vertical and horizontal directions. The front wall 1F and the rear wall 1R are shown in FIG. 1 . The right wall and the left wall are not shown. The furnace 1 defines a combustion space S. In this disclosure, the combustion space refers to a space in which fuel is combusted. An outlet is provided at the bottom of the furnace 1. For example, a hopper may be provided at the outlet.

[0023] The furnace 1 burns a fuel containing nitrogen. For example, in this embodiment, the furnace 1 uses a first fuel F1, a second fuel F2, and a third fuel F3. For example, in this embodiment, each of the first fuel F1 and the second fuel F2 is ammonia. Hereinafter, this embodiment will be described assuming that each of the first fuel F1 and the second fuel F2 is ammonia. In this embodiment, the third fuel F3 is a fuel having higher combustibility than ammonia. For example, the third fuel F3 may be a fossil fuel such as pulverized coal. The third fuel F3 is not limited thereto. For example, the furnace 1 may perform co-combustion of ammonia and the third fuel F3. Also, for example, the furnace 1 may perform mono-combustion of ammonia. Also, for example, the furnace 1 may burn only the third fuel F3 as needed. In other embodiments, the furnace 1 may use only ammonia as fuel. In this case, the furnace 1 may use a small amount of fossil fuel for ignition.

[0024] Combustion of the fuel generates exhaust gas Ex in the combustion space S. For example, the boiler 50 includes a superheater (not shown) installed on the upper part of the furnace 1. The superheater exchanges heat between the exhaust gas Ex and water, thereby generating steam. Furthermore, for example, the boiler 50 may further include a component (not shown) such as an economizer.

[0025] The boiler 50 is connected to a flue 2. The flue 2 guides the exhaust gas Ex from the boiler 50 to a chimney (not shown).

[0026] The furnace 1 includes a burner group 10 and an air port group 30 .

[0027] The burner group 10 includes one or more burners 11. In the present embodiment, the burner group 10 includes multiple burners 11. In other embodiments, the burner group 10 may include only a single burner 11. The burner 11 is provided on each of the side walls of the furnace 1, in the present embodiment, the front wall 1F and the rear wall 1R. For example, the burner group 10 includes multiple burners 11 arranged in multiple stages along the vertical direction, in the present embodiment, three stages. In other embodiments, the multiple burners 11 may be arranged in a single stage. In each of the front wall 1F and the rear wall 1R, each stage includes multiple burners 11 arranged at a distance from each other in the horizontal left-right direction (the direction perpendicular to the paper surface).

[0028] The burner 11 injects ammonia F1, ammonia F2, and a third fuel F3 into the combustion space S. The ammonia F1, ammonia F2, and the third fuel F3 are combusted in the combustion space S. For example, each of the ammonia F1 and the ammonia F2 may be gaseous ammonia or liquid ammonia.

[0029] For example, each burner 11 is fluidly connected to a tank (ammonia supply source) 3 via a fuel conduit L1. For example, the tank 3 stores liquid ammonia. For example, a vaporizer (not shown) may be provided in the fuel conduit L1, and gaseous ammonia may be supplied to each burner 11. Alternatively, liquid ammonia may be supplied to each burner 11. In another embodiment, an ammonia producer may be used as the ammonia supply source.

[0030] For example, each burner 11 is in fluid communication with a third fuel supply source 4 via a fuel conduit L2. For example, the third fuel supply source 4 may be a pulverizer that pulverizes coal into pulverized coal. In this case, the fuel conduit L2 may deliver the pulverized coal to the burner 11 by air. The third fuel supply source 4 is not limited to a pulverizer.

[0031] The burners 11 inject an oxidizer into the combustion space S. For example, in this embodiment, the oxidizer may be air A. Also, for example, in other embodiments, the boiler 50 may include a conduit (not shown) connecting the flue 2 to each burner 11, and the oxidizer may be a mixed gas of air A and exhaust gas Ex. For example, each burner 11 is in fluid communication with an air conduit L3 via an air box (not shown). The air conduit L3 supplies air A to the burners 11. For example, the air conduit L3 may be in fluid communication with a compressor (not shown) that supplies ambient air around the furnace 1 to the burners 11.

[0032] It should be noted that although in FIG. 1 the fuel conduit L1, the fuel conduit L2 and the air conduit L3 are shown for only a single burner 11 on the rear wall 1R, the fuel conduit L1, the fuel conduit L2 and the air conduit L3 are in fluid communication with all of the burners 11.

[0033] The airport group 30 includes at least one airport 31. In the present embodiment, the airport group 30 includes multiple airports 31. In other embodiments, the airport group 30 may include only a single airport 31. The airport 31 is provided on each of the side walls of the furnace 1, which in the present embodiment are the front wall 1F and the rear wall 1R. In the present embodiment, the multiple airports 31 are arranged in a single tier. In other embodiments, the multiple airports 31 may be arranged in multiple tiers along the vertical direction. On each of the front wall 1F and the rear wall 1R, the multiple airports 31 are arranged spaced apart from each other along the left-right direction.

[0034] The airport group 30 is disposed downstream of the burner group 10 in the combustion space S. Specifically, the airport group 30 is disposed above the burner group 10. The airport group 30 is disposed spaced apart from the burner group 10 in the vertical direction. For example, the distance between the airport group 30 and the burner group 10 in the vertical direction may be longer than the distance between adjacent burners 11 in the vertical direction.

[0035] The airports 31 inject an oxidizer into the combustion space S. For example, the oxidizer may be air A or a mixture of air A and exhaust gas Ex. For example, each airport 31 is in fluid communication with an air conduit L4 via an air box (not shown). The air conduit L4 supplies air A to the airports 31. For example, the air conduit L4 may be in fluid communication with a compressor (not shown) that supplies ambient air around the furnace 1 to the airports 31.

[0036] It should be noted that although the air conduit L4 is shown in FIG. 1 only for the air ports 31 on the rear wall 1R, the air conduit L4 is in fluid communication with all of the air ports 31.

[0037] 2 is a schematic diagram of the burners 11. For example, each burner 11 includes a body 12 and an oxidant passage 13. The burners 11 may further include other components.

[0038] For example, in this embodiment, the body 12 includes a first nozzle 12 a and a second nozzle 12 b. The first nozzle 12 a is configured to supply a first fuel (ammonia) F1 to the combustion space S, and the second nozzle 12 b is configured to supply a third fuel F3 to the combustion space S.

[0039] For example, the first nozzle 12a has a generally cylindrical shape. The first nozzle 12a includes an opening (first opening) O1 facing the combustion space S. For example, the opening O1 has a circular shape.

[0040] In this disclosure, unless otherwise specified, the "axial direction," "radial direction," and "circumferential direction" of the first nozzle 12a may be simply referred to as the "axial direction," "radial direction," and "circumferential direction."

[0041] The first nozzle 12a is in fluid communication with the fuel conduit L1. For example, in this embodiment, the fuel conduit L1 branches into a first branch pipe L11 and a second branch pipe L12. The first nozzle 12a is connected to the first branch pipe L11. The first branch pipe L11 supplies ammonia F1 to the first nozzle 12a. Therefore, the opening O1 of the first nozzle 12a injects the ammonia F1 into the combustion space S.

[0042] A valve V1 is provided in the first branch pipe L11. The valve V1 functions as a first fuel adjuster that adjusts the flow rate of ammonia F1 flowing through the first branch pipe L11. The valve V1 is communicably connected to the control device 90 via wire or wirelessly, and is controlled by the control device 90. For example, the control device 90 can adjust the amount of ammonia F1 supplied from the opening O1 of each burner 11 by controlling the opening degree of the valve V1.

[0043] For example, in the present embodiment, the main body 12 may include a single second nozzle 12b. In this case, for example, the second nozzle 12b may have a generally cylindrical shape that is larger than the first nozzle 12a, and the first nozzle 12a may pass through the interior of the second nozzle 12b. For example, the second nozzle 12b may be arranged coaxially with the first nozzle 12a. Alternatively, in other embodiments, the main body 12 may include a plurality of second nozzles 12b. In this case, the plurality of second nozzles 12b may be arranged around the first nozzle 12a so as to surround the first nozzle 12a.

[0044] The second nozzle 12b includes an opening (fourth opening) O4 facing the combustion space S. The opening O4 is disposed in a region radially outward from the opening O1 and radially inward from an opening O2, which will be described later. For example, if the main body 12 includes a single second nozzle 12b, the opening O4 has an annular shape. Alternatively, for example, if the main body 12 includes a plurality of second nozzles 12b, each of the openings O4 has a circular shape, and the plurality of openings O4 are arranged in a circular shape.

[0045] The second nozzle 12b is connected to the fuel conduit L2. The fuel conduit L2 supplies a third fuel F3 to the second nozzle 12b. For example, in this embodiment, the fuel conduit L2 supplies a fuel gas containing pulverized coal F3 and air. Therefore, the opening O4 of the second nozzle 12b injects the fuel gas containing pulverized coal F3 and air into the combustion space S.

[0046] A valve V2 is provided in the fuel conduit L2. The valve V2 functions as a third fuel adjuster that adjusts the flow rate of the third fuel F3 flowing through the fuel conduit L2. The valve V2 is communicatively connected to the control device 90 via wire or wirelessly, and is controlled by the control device 90. For example, the control device 90 can adjust the amount of the third fuel F3 supplied from the opening O4 of each burner 11 by controlling the aperture of the valve V2.

[0047] The oxidant flow path 13 is configured to supply an oxidant, in this embodiment, air A, to the combustion space S. In this embodiment, the oxidant flow path 13 is also configured to supply a premixed gas of ammonia F and air A to the combustion space S.

[0048] The oxidant flow path 13 is disposed radially outward of the main body 12. For example, the oxidant flow path 13 is continuous in the circumferential direction and has a generally truncated conical shape in this embodiment. For example, the oxidant flow path 13 may be disposed coaxially with the first nozzle 12a.

[0049] Air A is supplied to the oxidant flow path 13 from the air conduit L3 via a wind box (not shown).

[0050] A first damper D1 is provided in the oxidant flow path 13. The first damper D1 functions as a first oxidant adjuster that adjusts the flow rate of air A flowing through the oxidant flow path 13. An actuator M1 of the first damper D1 is communicably connected to the control device 90 via wire or wirelessly and is controlled by the control device 90. For example, the actuator M1 may be a motor. For example, the control device 90 adjusts the flow rate of air A supplied to the oxidant flow path 13 by controlling the opening degree of the first damper D1. Furthermore, in this embodiment, the burner 11 generates a swirl of the air A by the first damper D1.

[0051] In this embodiment, the oxidant flow path 13 branches into a first flow path 13a and a second flow path 13b at a position downstream of the first damper D1. Therefore, in this embodiment, a portion of the air A supplied from the first damper D1 flows into the first flow path 13a, and the remainder flows into the second flow path 13b. Each of the first flow path 13a and the second flow path 13b has a generally truncated conical shape. The first flow path 13a is located radially inward of the second flow path 13b.

[0052] The first flow passage 13a includes an opening (second opening) O2 facing the combustion space S. The opening O2 is disposed in a region radially outward of the opening O4, i.e., in a region radially outward of the opening O1. For example, the opening O2 has an annular shape.

[0053] A second damper D2 is provided in the first flow path 13a. The second damper D2 functions as a second oxidizer adjuster that adjusts the flow rate of air A flowing into the first flow path 13a. An actuator M2 of the second damper D2 is communicatively connected to the control device 90 via wire or wirelessly and is controlled by the control device 90. For example, the actuator M2 may be a motor. For example, the control device 90 can adjust the amount of air A flowing into the first flow path 13a, i.e., the amount of air A in the premixed gas (described in detail below) supplied from the opening O2 of each burner 11, by controlling the opening degree of the second damper D2. In addition, in this embodiment, the burner 11 generates a swirl of the air A by the second damper D2.

[0054] The first flow path 13a is connected to the second branch pipe L12 of the fuel conduit L1. The second branch pipe L12 supplies the second fuel (ammonia) F2 to the first flow path 13a. Specifically, as described above, air A from the second damper D2 flows through the first flow path 13a. Due to the ejector effect, the air A draws in ammonia F2 from the second branch pipe L12. The air A and ammonia F2 are mixed into a premixed gas in the first flow path 13a. Therefore, in this embodiment, the opening O2 of the first flow path 13a supplies the premixed gas containing air A and ammonia F2 to the combustion space S. In this embodiment, the first flow path 13a supplies the swirling premixed gas to the combustion space S from the radially outer side.

[0055] A valve V3 is provided in the second branch pipe L12. The valve V3 functions as a second fuel adjuster that adjusts the flow rate of ammonia F2 flowing through the second branch pipe L12. The valve V3 is communicably connected to the control device 90 via wire or wirelessly, and is controlled by the control device 90. For example, the control device 90 can adjust the amount of ammonia F2 in the premixed gas supplied from the opening O2 of each burner 11 by controlling the aperture of the valve V3.

[0056] The second flow passage 13b includes an opening (third opening) O3 facing the combustion space S. The opening O3 is disposed in a region radially outward of the opening O2. For example, the opening O3 has an annular shape. In the present embodiment, the opening O3 supplies air A from the first damper D1 to the combustion space S. For example, the control device 90 can adjust the amount of air A supplied from the opening O3 of each burner 11 by controlling the opening degree of the first damper D1 and the opening degree of the second damper D2. In the present embodiment, the second flow passage 13b supplies the swirling air A to the combustion space S from the radially outer side.

[0057] 1, a first sensor Se1 and a second sensor Se2 are provided at the outlet of the boiler 50. The positions of the first sensor Se1 and the second sensor Se2 are not limited thereto.

[0058] The first sensor Se1 measures the NOx concentration in the exhaust gas Ex from the combustion space S. For example, the first sensor Se1 may include one or more NOx sensors. For example, in this embodiment, the first sensor Se1 includes two NOx sensors spaced apart from each other in the left-right direction. Note that in FIG. 1 , only one NOx sensor is shown because the two NOx sensors overlap each other. For example, one NOx sensor is located near the right wall (not shown), and the other NOx sensor is located near the left wall (not shown). The number of NOx sensors is not limited to two, and may be one, three, or more. The first sensor Se1 is communicatively connected to the control device 90 via wire or wirelessly and transmits measured values ​​to the control device 90.

[0059] The second sensor Se2 measures the oxygen concentration in the exhaust gas Ex from the combustion space S. For example, the second sensor Se2 may be configured to detect one or more O ２ For example, in this embodiment, the second sensor Se2 may include two O sensors spaced apart from each other in the left-right direction. ２ In FIG. 1, two O ２ The sensors overlap each other, so one O ２ Only the sensor is shown. For example, one O ２ The sensor is placed near the right wall and the other ２ The sensor is placed near the left wall. ２ The number of sensors is not limited to two, and may be one, or three or more. The second sensor Se2 is communicably connected to the control device 90 via wire or wirelessly, and transmits a measurement value to the control device 90.

[0060] 2 , a third sensor Se3 and a fourth sensor Se4 are provided in the first flow path 13a of the oxidizer flow path 13 of the burner 11. The positions of the third sensor Se3 and the fourth sensor Se4 are not limited to this. The third sensor Se3 may be provided in each of the multiple burners 11, or may be provided only in a single representative burner 11. Similarly, the fourth sensor Se4 may be provided in each of the multiple burners 11, or may be provided only in a single representative burner 11.

[0061] The third sensor Se3 measures the concentration of the second fuel F2 in the premixed gas supplied from the opening O2 of each burner 11. For example, in this embodiment, the third sensor Se3 includes a gas sensor capable of detecting ammonia. The third sensor Se3 is communicably connected to the control device 90 via wire or wirelessly and transmits the measurement value to the control device 90.

[0062] The fourth sensor Se4 measures the oxygen concentration in the premixed gas supplied from the opening O2 of each burner 11. For example, the fourth sensor Se4 measures the oxygen concentration in the premixed gas supplied from the opening O2 of each burner 11. ２ The fourth sensor Se4 is communicably connected to the control device 90 via wire or wirelessly, and transmits a measurement value to the control device 90.

[0063] Referring to FIG. 1 , the control device 90 controls the combustion system 100. For example, the control device 90 may be realized by one or more computers. The control device 90 includes components such as a processor 90a, a storage device 90b, and a connector 90c, which are connected to each other via a bus. For example, the processor 90a includes a central processing unit (CPU). For example, the storage device 90b includes a hard disk, a read-only memory (ROM) in which programs and the like are stored, and a random access memory (RAM) as a work area. The control device 90 is connected to each component of the combustion system 100 via the connector 90c so as to be able to communicate with them via a wired or wireless connection. 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, buttons, or a touch panel. For example, the operation of the control device 90 may be realized by the processor 90a executing a program stored in the storage device 90b.

[0064] Next, the operation of the furnace 1 will be described.

[0065] Referring to FIG. 2, the burner 11 injects ammonia F1 into the combustion space S from an opening O1.

[0066] Furthermore, the burner 11 injects fuel gas containing a third fuel F3 from the opening O4 into the combustion space S. When air feeds the pulverized coal F3, the fuel gas also contains air.

[0067] The burner 11 also injects a premixed gas containing ammonia F2 and air A into the combustion space S from the opening O2.

[0068] The burner 11 also injects air A into the combustion space S from the opening O3.

[0069] In the combustion space S, the gas containing the ammonia F1, ammonia F2, the third fuel F3 and air A is combusted (first stage combustion).

[0070] In the first-stage combustion, a portion of the air A supplied to the oxidant passage 13 is mixed in advance with ammonia F2 (premixed gas from the opening O2). This premixed gas is inserted between the ammonia F1 from the opening O1 and the air A from the opening O3. Therefore, the local air ratio between the ammonia F1 from the opening O1 and the air A from the opening O3 is reduced. The reduction in the air ratio leads to a reduction in NOx. Therefore, in this embodiment, NOx is reduced.

[0071] Furthermore, the third fuel F3 in the fuel gas from the opening O4 has higher combustibility than the ammonia F1. Therefore, the third fuel F3 burns faster. The combustion gas of the third fuel F3 has a low oxygen concentration. This combustion gas is inserted between the ammonia F1 from the opening O1 and the air A from the opening O3. Therefore, the local air ratio between the ammonia F1 from the opening O1 and the air A from the opening O3 is further reduced. Therefore, in this embodiment, NOx emissions are further reduced.

[0072] Moreover, in this embodiment, the burner 11 supplies swirling air A from the radially outer side to the combustion space S. This forms a reducing atmosphere radially inward. Similarly, the burner 11 supplies swirling premixed gas from the radially outer side to the combustion space S. Similarly, this forms a reducing atmosphere radially inward. In this embodiment, the opening O1 supplies ammonia F1 that is not premixed radially inward. The reducing atmosphere can thermally decompose the ammonia F1 supplied from the opening O1, thereby reducing NOx.

[0073] Alternatively, the premixed gas may contain only ammonia F2 and air A. For example, when ammonia is mixed with the fuel gas from the opening O4, the fuel gas contains pulverized coal, air, and ammonia. However, ammonia may affect the combustion of the pulverized coal in the fuel gas, potentially resulting in poor ignition and combustion of the fuel gas. This may lead to the generation of CO. In this embodiment, the fuel gas containing pulverized coal and air and the premixed gas containing ammonia F2 are supplied separately to the combustion space S, thereby maintaining good ignition and combustion of the pulverized coal.

[0074] 1 , the combustion gas from the burner 11 flows to a region in front of the airport 31. The airport 31 injects air A into the combustion space S. Unburned fuel (unburned ammonia and unburned third fuel) contained in the combustion gas from the burner 11 is completely combusted by the air from the airport 31 (second-stage combustion).

[0075] For example, in the first-stage combustion described above, the local air ratio may fluctuate depending on various factors, which may lead to an increase in NOx. In this embodiment, the amounts of ammonia F1, ammonia F2, and air A are adjusted based on the concentrations of predetermined components in the premixed gas and the exhaust gas Ex to control the local air ratio.

[0076] For example, the control device 90 receives measurement values ​​from the first sensor Se1, the second sensor Se2, the third sensor Se3, and the fourth sensor Se4 at predetermined intervals during operation of the furnace 1. Based on the received measurement values, the processor 90a of the control device 90 adjusts at least one of the amount of ammonia F1 supplied from the opening O1, the amount of third fuel F3 and the amount of air in the fuel gas supplied from the opening O4, the amount of ammonia F2 and the amount of air A in the premixed gas supplied from the opening O2, and the amount of air A supplied from the opening O3.

[0077] For example, the processor 90a adjusts at least one of the amount of ammonia F1 supplied from the opening O1 and the amount of ammonia F2 in the premixed gas supplied from the opening O2 based on the NOx concentration in the exhaust gas Ex from the first sensor Se1.

[0078] For example, when the NOx concentration from the first sensor Se1 is higher than a predetermined upper limit value, the processor 90a increases the ratio of ammonia F2 in the premixed gas to the total ammonia supplied to the combustion space S. For example, the processor 90a increases the amount of ammonia F2 in the premixed gas in each burner 11 and decreases the amount of ammonia F1 supplied from the opening O1.

[0079] This configuration reduces the air ratio in the premixed gas, thereby reducing the local air ratio in the premixed gas between the ammonia F1 from the opening O1 and the air A from the opening O3, thereby reducing NOx emissions.

[0080] As described above, the first sensor Se1 according to this embodiment includes two NOx sensors spaced apart from each other in the left-right direction. For example, if the difference between the NOx concentrations from the two NOx sensors is higher than a predetermined upper limit, the processor 90a may adjust at least one of the amount of ammonia F1 supplied from the openings O1 and the amount of ammonia F2 in the premixed gas in the multiple burners 11 so that the difference between the two NOx concentrations is reduced to or below the upper limit. This configuration allows for good combustion balance between the multiple burners 11 in the left-right direction.

[0081] Also, for example, the processor 90a adjusts at least one of the amount of air in the fuel gas supplied from the opening O4, the amount of air A in the premixed gas supplied from the opening O2, and the amount of air A supplied from the opening O3 based on the oxygen concentration in the exhaust gas Ex from the second sensor Se2.

[0082] For example, when the oxygen concentration from the second sensor Se2 is higher than a predetermined upper limit, the processor 90a reduces the total amount of air supplied to the combustion space S. For example, in each burner 11, the processor 90a may reduce the amount of air in the fuel gas supplied from the opening O4, the amount of air A in the premixed gas supplied from the opening O2, and the amount of air A supplied from the opening O3 while maintaining the ratio between them.

[0083] With this configuration, it is possible to reduce excess oxygen and lower the combustion temperature, thereby reducing thermal NOx.

[0084] As described above, the second sensor Se2 according to this embodiment is composed of two O sensors arranged at a distance from each other in the left-right direction. ２ For example, two O ２If the difference between the oxygen concentrations from the sensors is higher than a predetermined upper limit, the processor 90a may adjust at least one of the amount of air in the fuel gas supplied from the opening O4, the amount of air A in the premixed gas supplied from the opening O2, and the amount of air A supplied from the opening O3 in the multiple burners 11 so that the difference between the two oxygen concentrations is reduced to or below the upper limit. With this configuration, good combustion balance can be achieved between the multiple burners 11 in the left-right direction.

[0085] Also, for example, the processor 90a adjusts at least one of the amount of ammonia F2 and the amount of air A in the premixed gas based on the concentration of ammonia F2 in the premixed gas from the third sensor Se3.

[0086] For example, the processor 90a reduces the amount of ammonia F2 in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is higher than a predetermined upper limit. For example, if the third sensor Se3 is provided in each of the multiple burners 11, the processor 90a may reduce the amount of ammonia F2 in the premixed gas only in the burner 11 where the concentration of ammonia F2 is higher than the upper limit. Alternatively, if the third sensor Se3 is provided in a single representative burner 11, the processor 90a may reduce the amount of ammonia F2 in the premixed gas in each burner 11. Also, alternatively, the processor 90a may increase the amount of air A in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is higher than the upper limit.

[0087] Also, for example, the processor 90a may increase the amount of ammonia F2 in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is lower than a predetermined lower limit. For example, if the third sensor Se3 is provided in each of the multiple burners 11, the processor 90a may increase the amount of ammonia F2 in the premixed gas only in the burner 11 where the concentration of ammonia F2 is lower than the lower limit. Alternatively, if the third sensor Se3 is provided in a single representative burner 11, the processor 90a may increase the amount of ammonia F2 in the premixed gas in each burner 11. Also, alternatively, the processor 90a may decrease the amount of air A in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is lower than the lower limit.

[0088] With this configuration, the air ratio of the premixed gas can be maintained within a desired range, thereby achieving the intended combustion state.

[0089] Also, for example, the processor 90a adjusts at least one of the amount of ammonia F2 and the amount of air A in the premixed gas based on the oxygen concentration in the premixed gas from the fourth sensor Se4.

[0090] For example, the processor 90a increases the amount of ammonia F2 in the premixed gas when the oxygen concentration from the fourth sensor Se4 is higher than a predetermined upper limit. For example, if the fourth sensor Se4 is provided in each of the multiple burners 11, the processor 90a may increase the amount of ammonia F2 in the premixed gas only in the burner 11 where the oxygen concentration is higher than the upper limit. Alternatively, if the fourth sensor Se4 is provided in a single representative burner 11, the processor 90a may increase the amount of ammonia F2 in the premixed gas in each burner 11. Also, alternatively, the processor 90a may decrease the amount of air A in the premixed gas when the oxygen concentration from the fourth sensor Se4 is higher than the upper limit.

[0091] Also, for example, the processor 90a may reduce the amount of ammonia F2 in the premixed gas when the oxygen concentration from the fourth sensor Se4 is lower than a predetermined lower limit. For example, if the fourth sensor Se4 is provided in each of the multiple burners 11, the processor 90a may reduce the amount of ammonia F2 in the premixed gas only in the burner 11 where the oxygen concentration is lower than the lower limit. Alternatively, if the fourth sensor Se4 is provided in a single representative burner 11, the processor 90a may reduce the amount of ammonia F2 in the premixed gas in each burner 11. Also, alternatively, the processor 90a may increase the amount of air A in the premixed gas when the oxygen concentration from the fourth sensor Se4 is lower than the lower limit.

[0092] With this configuration, the air ratio of the premixed gas can be maintained within a desired range, thereby achieving the intended combustion state.

[0093] According to the above-described configuration, an increase in NOx can be suppressed regardless of changes in the components in the gas due to various factors.

[0094] The various upper and lower limit values ​​described above may be determined in advance by experiment, analysis, or calculation, and may be stored in the storage device 90b.

[0095] As described above, the combustion system 100 according to this embodiment includes a plurality of burners 11 facing the combustion space S, sensors Se1, Se2, Se3, and Se4 that measure the concentrations of predetermined components in the gas, and a control device 90. Each of the burners 11 includes an opening O1 that supplies ammonia F1 to the combustion space S, an opening O2 that is located in a region radially outward of the opening O1 and that supplies a premixed gas of ammonia F2 and air A to the combustion space S, and an opening O3 that is located in a region radially outward of the opening O2 and that supplies air A to the combustion space S. The control device 90 controls at least one of the burners 11 based on the measurements of the sensors Se1, Se2, Se3, and Se4 to adjust at least one of the amount of ammonia F1 supplied from the opening O1, the amount of ammonia F2 in the premixed gas, the amount of air A in the premixed gas, and the amount of air A supplied from the opening O3. This configuration enables NOx reduction regardless of changes in the components in the gas due to various factors.

[0096] Furthermore, in the combustion system 100, the sensor includes a first sensor Se1 that measures the NOx concentration in the exhaust gas Ex from the combustion space S, and the control device 90 adjusts at least one of the amount of ammonia F1 supplied from the opening O1 and the amount of ammonia F2 in the premixed gas based on the measurement value of the first sensor Se1. With this configuration, when the NOx concentration is higher than the upper limit value, it is possible to reduce the local air ratio in the premixed gas between the ammonia F1 from the opening O1 and the air A from the opening O3. As a result, it is possible to reduce NOx.

[0097] In the combustion system 100, the sensor also includes a second sensor Se2 that measures the oxygen concentration in the exhaust gas from the combustion space S, and the control device 90 adjusts at least one of the amount of air A in the premixed gas and the amount of air A supplied from the opening O3 based on the measurement value of the second sensor Se2. This configuration can reduce excess oxygen and lower the combustion temperature, thereby reducing thermal NOx.

[0098] Furthermore, in the combustion system 100, the sensor includes a third sensor Se3 that measures the concentration of ammonia F2 in the premixed gas, and the control device 90 adjusts at least one of the amount of ammonia F2 and the amount of air A in the premixed gas based on the measurement value of the third sensor Se3. With this configuration, the air ratio in the premixed gas can be maintained within a desired range, thereby achieving the intended combustion state.

[0099] Furthermore, in the combustion system 100, the sensors include a fourth sensor Se4 that measures the oxygen concentration in the premixed gas, and the control device 90 adjusts at least one of the amount of ammonia F2 and the amount of air A in the premixed gas based on the measurement value of the fourth sensor. With this configuration, the air ratio in the premixed gas can be maintained within a desired range, thereby achieving the intended combustion state.

[0100] Furthermore, in the combustion system 100, each of the burners 11 includes an opening O4 disposed radially outward from the opening O1 and radially inward from the opening O2, for supplying a third fuel F3 having higher combustibility than ammonia to the combustion space S. The third fuel F3 burns faster. The combustion gas of the third fuel F3 contributes to a reduction in the local air ratio. Therefore, NOx emissions can be further reduced.

[0101] The burners 11 are arranged on each of the front wall 1F and the rear wall 1R at a distance from one another in the left-right direction, the first sensor Se1 includes at least two NOx sensors that are arranged at a distance from one another in the left-right direction and are capable of measuring NOx concentrations, and the control device 90 controls at least one of the burners 11 based on the measurements of the at least two NOx sensors to adjust at least one of the amount of ammonia F1 supplied from the opening O1 and the amount of ammonia F2 in the premixed gas. With this configuration, good combustion balance can be achieved among the burners 11 in the left-right direction.

[0102] In the combustion system 100, the second sensor Se2 includes at least two O sensors capable of measuring oxygen concentration, which are arranged spaced apart from each other along the left-right direction. ２The control device 90 includes at least two O ２ Based on the sensor measurement values, at least one of the plurality of burners 11 is controlled to adjust at least one of the amount of air A in the premixed gas and the amount of air A supplied from the opening O3. With this configuration, good combustion balance can be obtained between the plurality of burners 11 in the left-right direction.

[0103] In the combustion system 100, the second opening O2 supplies premixed gas to the combustion space S, and the third opening O3 supplies air A to the combustion space S.

[0104] Next, other embodiments will be described.

[0105] 3 is a schematic diagram of a burner 11A according to another embodiment. The burner 11A differs from the burner 11 in that the second opening O2 supplies air A to the combustion space S and the third opening O3 supplies premixed gas to the combustion space S.

[0106] Specifically, in this embodiment, the first damper D1 is provided in the second flow path 13b. In this embodiment, the first damper D1 adjusts the flow rate of the air A flowing through the second flow path 13b. For example, by controlling the opening degree of the first damper D1, the control device 90 can adjust the flow rate of the air A supplied to the second flow path 13b, i.e., the amount of air A in the premixed gas supplied from the opening O3 of each burner 11A.

[0107] In this embodiment, the second branch pipe L12 of the fuel conduit L1 is connected to the second flow path 13b instead of the first flow path 13a. The second branch pipe L12 supplies the second fuel (ammonia) F2 to the second flow path 13b. Specifically, air A from the first damper D1 flows through the second flow path 13b. Due to the ejector effect, the air A draws ammonia F2 from the second branch pipe L12. The air A and ammonia F2 are mixed into a premixed gas in the second flow path 13b. Therefore, in this embodiment, the opening O3 of the second flow path 13b supplies the premixed gas containing air A and ammonia F2 to the combustion space S. The control device 90 can adjust the amount of ammonia F2 in the premixed gas supplied from the opening O3 of each burner 11A by controlling the aperture of the valve V3.

[0108] In contrast, in this embodiment, the opening O2 supplies air A from the second damper D2 to the combustion space S. For example, the control device 90 can adjust the amount of air A supplied from the opening O2 of each burner 11A by controlling the opening degree of the second damper D2.

[0109] In this embodiment, the third sensor Se3 and the fourth sensor Se4 are provided in the second flow path 13b instead of the first flow path 13a.

[0110] In other respects, burner 11A may be identical to burner 11 described above.

[0111] Next, the operation of the furnace 1 equipped with the burner 11A will be described.

[0112] The burner 11A injects ammonia F1 into the combustion space S from the opening O1.

[0113] Furthermore, the burner 11A injects fuel gas containing a third fuel F3 from the opening O4 into the combustion space S. When air feeds the pulverized coal F3, the fuel gas also contains air.

[0114] The burner 11A also injects air A into the combustion space S from the opening O2.

[0115] The burner 11A also injects a premixed gas containing ammonia F2 and air A into the combustion space S from the opening O3.

[0116] In the combustion space S, the gas containing the ammonia F1, ammonia F2, the third fuel F3 and air A is combusted (first stage combustion).

[0117] In this embodiment, in the first stage combustion, a portion of the air A supplied to the oxidant passage 13 is mixed in advance with ammonia F2 (premixed gas from the opening O3). Therefore, in this embodiment as well, NOx is reduced.

[0118] Furthermore, the third fuel F3 in the fuel gas from the opening O4 has higher combustibility than the ammonia F1. Therefore, the third fuel F3 burns faster. The combustion gas of the third fuel F3 has a low oxygen concentration. This combustion gas is inserted between the ammonia F1 from the opening O1 and the air A from the opening O2. Therefore, the local air ratio between the ammonia F1 from the opening O1 and the air A from the opening O2 is further reduced. Therefore, in this embodiment, NOx emissions are further reduced.

[0119] As in the above embodiment, the unburned fuel (unburned ammonia and unburned third fuel) contained in the combustion gas from the burner 11A is completely combusted in the second-stage combustion.

[0120] As in the above embodiment, the local air ratio may fluctuate in the first stage combustion depending on various factors, which may lead to an increase in NOx. In this embodiment, the amounts of ammonia F1, ammonia F2, and air A are adjusted based on the concentrations of predetermined components in the premixed gas and the exhaust gas Ex to control the local air ratio.

[0121] For example, the control device 90 receives measurement values ​​from the first sensor Se1, the second sensor Se2, the third sensor Se3, and the fourth sensor Se4 at predetermined intervals during operation of the furnace 1. Based on the received measurement values, the processor 90a of the control device 90 adjusts at least one of the amount of ammonia F1 supplied from the opening O1, the amount of third fuel F3 and the amount of air in the fuel gas supplied from the opening O4, the amount of air A supplied from the opening O2, and the amount of ammonia F2 and the amount of air A in the premixed gas supplied from the opening O3.

[0122] For example, the processor 90a adjusts at least one of the amount of ammonia F1 supplied from the opening O1 and the amount of ammonia F2 in the premixed gas supplied from the opening O3 based on the NOx concentration in the exhaust gas Ex from the first sensor Se1.

[0123] For example, when the NOx concentration from the first sensor Se1 is higher than a predetermined upper limit value, the processor 90a increases the ratio of ammonia F2 in the premixed gas to the total ammonia supplied to the combustion space S. For example, the processor 90a increases the amount of ammonia F2 in the premixed gas and decreases the amount of ammonia F1 supplied from the opening O1 in each burner 11A.

[0124] With this configuration, the air ratio of the premixed gas from the opening O3 is reduced, thereby reducing NOx.

[0125] As described above, the first sensor Se1 includes two NOx sensors spaced apart from each other in the left-right direction. For example, if the difference between the NOx concentrations from the two NOx sensors is higher than a predetermined upper limit, the processor 90a may adjust at least one of the amount of ammonia F1 supplied from the openings O1 and the amount of ammonia F2 in the premixed gas in the multiple burners 11A so that the difference between the two NOx concentrations is reduced to or below the upper limit. With this configuration, good combustion balance can be achieved between the multiple burners 11A in the left-right direction.

[0126] Also, for example, the processor 90a adjusts at least one of the amount of air in the fuel gas supplied from the opening O4, the amount of air A supplied from the opening O2, and the amount of air A in the premixed gas supplied from the opening O3 based on the oxygen concentration in the exhaust gas Ex from the second sensor Se2.

[0127] For example, when the oxygen concentration from the second sensor Se2 is higher than a predetermined upper limit, the processor 90a reduces the total amount of air supplied to the combustion space S. For example, in each burner 11A, the processor 90a may reduce the amount of air in the fuel gas supplied from the opening O4, the amount of air A supplied from the opening O2, and the amount of air A in the premixed gas supplied from the opening O3 while maintaining the ratio between them.

[0128] With this configuration, it is possible to reduce excess oxygen and lower the combustion temperature, thereby reducing thermal NOx.

[0129] As described above, the second sensor Se2 is composed of two O sensors spaced apart from each other along the left-right direction. ２ For example, two O ２ If the difference between the oxygen concentrations from the sensors is higher than a predetermined upper limit, the processor 90a may adjust at least one of the amount of air in the fuel gas supplied from the opening O4, the amount of air A supplied from the opening O2, and the amount of air A in the premixed gas supplied from the opening O3 in the plurality of burners 11A so that the difference between the two oxygen concentrations is reduced to or below the upper limit. With this configuration, good combustion balance can be achieved between the plurality of burners 11A in the left-right direction.

[0130] Also, for example, the processor 90a adjusts at least one of the amount of ammonia F2 and the amount of air A in the premixed gas based on the concentration of ammonia F2 in the premixed gas from the third sensor Se3.

[0131] For example, the processor 90a reduces the amount of ammonia F2 in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is higher than a predetermined upper limit. For example, if the third sensor Se3 is provided in each of the multiple burners 11A, the processor 90a may reduce the amount of ammonia F2 in the premixed gas only in the burner 11A where the concentration of ammonia F2 is higher than the upper limit. Alternatively, if the third sensor Se3 is provided in a single representative burner 11A, the processor 90a may reduce the amount of ammonia F2 in the premixed gas in each burner 11A. Also, alternatively, the processor 90a may increase the amount of air A in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is higher than the upper limit.

[0132] Furthermore, for example, the processor 90a may increase the amount of ammonia F2 in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is lower than a predetermined lower limit. For example, if the third sensor Se3 is provided for each of the multiple burners 11A, the processor 90a may increase the amount of ammonia F2 in the premixed gas only in the burner 11A where the concentration of ammonia F2 is lower than the lower limit. Alternatively, if the third sensor Se3 is provided for a single representative burner 11A, the processor 90a may increase the amount of ammonia F2 in the premixed gas in each burner 11A. Alternatively, the processor 90a may decrease the amount of air A in the premixed gas when the concentration of ammonia F2 from the third sensor Se3 is lower than the lower limit.

[0133] With this configuration, the air ratio of the premixed gas can be maintained within a desired range, thereby achieving the intended combustion state.

[0134] Also, for example, the processor 90a adjusts at least one of the amount of ammonia F2 and the amount of air A in the premixed gas based on the oxygen concentration in the premixed gas from the fourth sensor Se4.

[0135] For example, the processor 90a may increase the amount of ammonia F2 in the premixed gas when the oxygen concentration from the fourth sensor Se4 is higher than a predetermined upper limit. For example, if the fourth sensor Se4 is provided in each of the multiple burners 11A, the processor 90a may increase the amount of ammonia F2 in the premixed gas only in the burner 11A where the oxygen concentration is higher than the upper limit. Alternatively, if the fourth sensor Se4 is provided in a single representative burner 11A, the processor 90a may increase the amount of ammonia F2 in the premixed gas in each burner 11A. Also, alternatively, the processor 90a may decrease the amount of air A in the premixed gas when the oxygen concentration from the fourth sensor Se4 is higher than the upper limit.

[0136] Also, for example, the processor 90a may reduce the amount of ammonia F2 in the premixed gas when the oxygen concentration from the fourth sensor Se4 is lower than a predetermined lower limit. For example, if the fourth sensor Se4 is provided in each of the multiple burners 11A, the processor 90a may reduce the amount of ammonia F2 in the premixed gas only in the burner 11A where the oxygen concentration is lower than the lower limit. Alternatively, if the fourth sensor Se4 is provided in a single representative burner 11A, the processor 90a may reduce the amount of ammonia F2 in the premixed gas in each burner 11A. Also, alternatively, the processor 90a may increase the amount of air A in the premixed gas when the oxygen concentration from the fourth sensor Se4 is lower than the lower limit.

[0137] With this configuration, the air ratio of the premixed gas can be maintained within a desired range, thereby achieving the intended combustion state.

[0138] The system 100 including the burner 11A has the same effects as the system 100 including the burner 11 according to the above embodiment. In particular, in this embodiment, the opening O2 supplies air A to the combustion space S, and the opening O3 supplies premixed gas to the combustion space S.

[0139] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that such modifications also fall within the technical scope of the present disclosure.

[0140] For example, in the above embodiment, ammonia is used as the first fuel F1 and the second fuel F2 containing nitrogen. For example, blast furnace gas (BFG), converter gas (LDG), and coke oven gas (COG) each contain nitrogen, so NOx generation can be a problem even when these fuels are used. Therefore, in other embodiments, BFG, LDG, or COG may be used as at least one of the first fuel F1 and the second fuel F2. In still other embodiments, each of the first fuel F1 and the second fuel F2 may include at least one of ammonia, BFG, LDG, and COG. Note that when the second fuel F2 is BFG, LDG, or COG, the third sensor that measures the concentration of the second fuel F2 in the premixed gas may be a sensor that detects H ２ Alternatively, it may be a gas sensor capable of detecting CO.

[0141] For example, in the above embodiment, ammonia F1 and ammonia F2 are supplied from the same tank 3. In other embodiments, ammonia F1 and ammonia F2 may be supplied from different sources.

[0142] For example, in the above embodiment, the burner 11, 11A includes the second nozzle 12b for injecting the third fuel F3. In other embodiments, the burner 11, 11A may not include the second nozzle 12b, and may not use the third fuel F3.

[0143] In addition, for example, in the above embodiment, the combustion system 100 includes all of the first sensor Se1, the second sensor Se2, the third sensor Se3, and the fourth sensor Se4. In other embodiments, the combustion system 100 may not include some of the first sensor Se1, the second sensor Se2, the third sensor Se3, and the fourth sensor Se4.

[0144] The present disclosure provides ２ It can promote the use of ammonia, which leads to reduced emissions, thereby contributing, for example, to Sustainable Development Goal (SDG) 7 "Ensure access to affordable, reliable, sustainable and modern energy" and SDG 13 "Take urgent action to combat climate change and its impacts".

[0145] 1F Front wall 1R Rear wall 11 Burner 11A Burner 90 Control device 100 Combustion system A Air Ex Exhaust gas F1 First fuel F2 Second fuel F3 Third fuel O1 Opening (first opening) O2 Opening (second opening) O3 Opening (third opening) O4 Opening (fourth opening) S Combustion space Se1 First sensor Se2 Second sensor Se3 Third sensor Se4 Fourth sensor

Claims

1. A combustion system comprising: one or more burners facing a combustion space, each of the one or more burners including: a first opening that supplies a first fuel containing nitrogen to the combustion space; a second opening, located in a region radially outward of the first opening, that supplies one of air and a premixed gas to the combustion space, the premixed gas containing a second fuel containing nitrogen and air; and a third opening, located in a region radially outward of the second opening, that supplies the other of air and the premixed gas to the combustion space; a sensor that measures the concentration of a predetermined component in gas; and a control device that controls at least one of the one or more burners based on the measurement value of the sensor to adjust at least one of the amount of the first fuel supplied from the first opening, the amount of the second fuel in the premixed gas, the amount of air in the premixed gas, and the amount of air supplied from the second opening or the third opening.

2. The combustion system of claim 1, wherein the first fuel and the second fuel each include ammonia.

3. The combustion system according to claim 1, wherein the sensor includes a first sensor that measures a NOx concentration in exhaust gas from the combustion space, and the control device adjusts at least one of the amount of the first fuel supplied from the first opening and the amount of the second fuel in the premixed gas based on the measurement value of the first sensor.

4. The combustion system according to claim 1, wherein the sensor includes a second sensor that measures the oxygen concentration in the exhaust gas from the combustion space, and the control device adjusts at least one of the amount of air in the premixed gas and the amount of air supplied from the second opening or the third opening based on the measurement value of the second sensor.

5. The combustion system according to claim 1, wherein the sensor includes a third sensor that measures the concentration of the second fuel in the premixed gas, and the control device adjusts at least one of the amount of the second fuel and the amount of air in the premixed gas based on the measurement value of the third sensor.

6. The combustion system according to claim 1, wherein the sensor includes a fourth sensor that measures an oxygen concentration in the premixed gas, and the control device adjusts at least one of the amount of the second fuel and the amount of air in the premixed gas based on the measurement value of the fourth sensor.

7. The combustion system according to claim 1, wherein each of the one or more burners includes a fourth opening arranged in a region radially outward from the first opening and radially inward from the second opening, for supplying a third fuel having higher combustibility than the first fuel to the combustion space.

8. The combustion system according to claim 3, wherein the one or more burners include a plurality of burners arranged on a wall at a distance from one another along a predetermined horizontal direction, the first sensor includes at least two sensors capable of measuring NOx concentrations that are arranged at a distance from one another along the predetermined horizontal direction, and the control device controls at least one of the plurality of burners based on measurements of the at least two sensors to adjust at least one of the amount of the first fuel supplied from the first opening and the amount of the second fuel in the premixed gas.

9. The combustion system according to claim 4, wherein the one or more burners include a plurality of burners arranged on the wall at a distance from one another along a predetermined horizontal direction, the second sensor includes at least two sensors capable of measuring oxygen concentration that are arranged at a distance from one another along the predetermined horizontal direction, and the control device controls at least one of the plurality of burners based on the measurements of the at least two sensors to adjust at least one of the amount of air in the premixed gas and the amount of air supplied from the second opening or the third opening.

10. The combustion system of claim 1, wherein the second opening supplies the premixed gas to the combustion space, and the third opening supplies air to the combustion space.

11. The combustion system of claim 1, wherein the second opening supplies air to the combustion space, and the third opening supplies the premixed gas to the combustion space.

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