Ammonia mixed-fuel combustion burner, and method for manufacturing ammonia mixed-fuel combustion system using same

Abstract

An ammonia mixed-fuel combustion burner (4) is installed in a combustion chamber (2) and causes ammonia and a carbon-containing fuel that are supplied into the combustion chamber (2) to be combusted. The ammonia mixed-fuel combustion burner (4) comprises: a carbon-containing fuel supply channel (41) in which the carbon-containing fuel and air are mixed and through which the same is supplied into the combustion chamber (2); and an ammonia supply channel (42) in which ammonia and air are mixed and through which the same is supplied into the combustion chamber (2).

Description

Ammonia co-firing burner and method for manufacturing an ammonia co-firing system using the same

[0001] The present disclosure relates to an ammonia co-firing burner and a method for manufacturing an ammonia co-firing system using the same.

[0002] CO emissions from coal-fired power plants ２ In order to reduce the amount of ammonia, the development of mixed combustion of ammonia and pulverized coal (hereinafter referred to as mixed combustion) technology is underway. ３ ) is a compound of hydrogen atoms (H) and nitrogen atoms (N), and does not contain carbon (C) as a constituent atom, so when it is burned, it does not produce CO ２ It is expected to be used as a zero-emission fuel.

[0003] On the other hand, in a boiler that mixes ammonia as part of the fuel, there is a concern that an increase in nitrogen oxides (NOx) associated with the combustion of ammonia will occur as a result of a portion of the fuel being replaced from coal by ammonia.Patent Document 1 discloses that in an ammonia mixed-fuel system in which an ammonia burner and a pulverized coal burner are provided in different positions, the generation of NOx can be suppressed by providing a control device that controls the supply amounts of ammonia fuel, pulverized coal, and combustion air.

[0004] JP 2023-39881 A

[0005] However, in Patent Document 1, when ammonia and a carbon-containing fuel are mixed and burned in the same space, the combustion of the ammonia and the carbon-containing fuel competes with each other. Therefore, the optimal amount of oxygen for each combustion is not supplied, and NO Ｘ This leads to an increase in emissions and unburned fuel in ash, which is a problem.

[0006] Therefore, the present disclosure provides a method for producing ammonia by premixing ammonia and a carbon-containing fuel with air before combustion, supplying them to a combustion chamber, and burning them in separate spaces to produce NO. Ｘ The object of the present invention is to provide an ammonia co-firing burner with reduced emissions and a method for manufacturing an ammonia co-firing system using the same.

[0007] The ammonia co-fuel burner according to the present disclosure is an ammonia co-fuel burner that is installed in a combustion chamber and supplies ammonia and a carbon-containing fuel into the combustion chamber to combust them, and includes a carbon-containing fuel supply flow path that mixes the carbon-containing fuel and air and supplies the mixture into the combustion chamber, and an ammonia supply flow path that mixes the ammonia and air and supplies the mixture into the combustion chamber.

[0008] The carbon-containing fuel supply passage may be a first injection nozzle that mixes the carbon-containing fuel and air and injects the mixture into the combustion chamber, and the ammonia supply passage may be a second injection nozzle that mixes the ammonia and air and injects the mixture into the combustion chamber.

[0009] The first injection nozzle is formed to surround the second injection nozzle and has a double-cylinder shape arranged concentrically with the second injection nozzle, the injection direction of the first injection nozzle and the injection direction of the second injection nozzle are oriented in the same direction as the nozzle axis, and the first injection nozzle may be provided with an air supply flow path that supplies air into the combustion chamber through a swirler.

[0010] The second injection nozzle is formed to surround the first injection nozzle and has a double-cylinder shape arranged concentrically with the first injection nozzle, the injection direction of the first injection nozzle and the injection direction of the second injection nozzle are oriented in the same direction as the nozzle axis, and may be provided with an air supply flow path that supplies air into the combustion chamber through a swirler.

[0011] When ammonia and air are mixed in the ammonia supply channel, the equivalence ratio between ammonia and air may be 1.0 or more.

[0012] The manufacturing method for an ammonia co-firing system according to the present disclosure is a manufacturing method for an ammonia co-firing system having a combustion chamber and an ammonia co-firing burner that supplies ammonia and a carbon-containing fuel into the combustion chamber and burns them, and the burner is modified by connecting a connecting path to an air flow path that supplies air into the combustion chamber, and an ammonia supply flow path that mixes ammonia and air and supplies the mixed ammonia into the combustion chamber, and a swirler is installed in the ammonia supply flow path.

[0013] The manufacturing method for an ammonia co-firing system according to the present disclosure is a manufacturing method for an ammonia co-firing system having a combustion chamber and an ammonia co-firing burner for supplying ammonia and a carbon-containing fuel into the combustion chamber and burning them, wherein a first injection nozzle for mixing the carbon-containing fuel and air and injecting the mixture into the combustion chamber is formed to surround the ammonia injection nozzle for injecting ammonia into the combustion chamber, and the burner has a double-cylinder shape that is concentric with the ammonia injection nozzle. The burner is modified by connecting a connecting path to an air supply flow path that supplies air into the combustion chamber, and an ammonia supply flow path that mixes ammonia and air and supplies the mixture into the combustion chamber, and a swirler is installed in the ammonia supply flow path.

[0014] The air supply flow path may be divided into a plurality of air supply flow paths, and modified by connecting a connecting path to at least some of the plurality of air supply flow paths, to provide an ammonia supply flow path that mixes ammonia and air and supplies the mixture into the combustion chamber.

[0015] The manufacturing method for an ammonia co-firing system according to the present disclosure is a manufacturing method for an ammonia co-firing system having a combustion chamber and an ammonia co-firing burner that supplies ammonia and a carbon-containing fuel into the combustion chamber and burns them, wherein a first injection nozzle that mixes the carbon-containing fuel and air and injects the mixture into the combustion chamber is formed to surround the ammonia injection nozzle that injects ammonia into the combustion chamber, and the burner has a double-cylinder shape that is concentric with the ammonia injection nozzle, and is modified by connecting a connecting path to the ammonia injection nozzle, and a second injection nozzle that mixes ammonia and air and supplies the mixture into the combustion chamber is installed.

[0016] The injection direction of the first injection nozzle and the injection direction of the second injection nozzle may be oriented in the same direction as the nozzle axis, and an air supply passage may be provided to supply air through a swirler into the combustion chamber.

[0017] The method for manufacturing an ammonia co-firing system according to the present disclosure is a method for manufacturing an ammonia co-firing system having a combustion chamber and an ammonia co-firing burner for supplying ammonia and a carbon-containing fuel into the combustion chamber and burning them, and the burner is equipped with a first injection nozzle for mixing the carbon-containing fuel and air and injecting the mixture into the combustion chamber, and is modified by installing a second injection nozzle, which mixes ammonia and air and injects the mixture into the combustion chamber, outside the first injection nozzle.

[0018] The second injection nozzle may be formed to surround the first injection nozzle and may have a double-cylinder shape arranged concentrically with the first injection nozzle, and the injection directions of the first injection nozzle and the second injection nozzle may be oriented in the same direction as the nozzle axis, and an air supply flow path may be provided to supply air into the combustion chamber through a swirler.

[0019] According to the present disclosure, ammonia and a carbon-containing fuel are premixed with air before combustion and supplied to a combustion chamber, and then combusted in separate spaces to produce NO. Ｘ It is possible to provide an ammonia co-firing burner with reduced emissions and a method for manufacturing an ammonia co-firing system using the same.

[0020] Fig. 1 is a schematic diagram showing the configuration of a main part of a boiler provided in an ammonia co-firing system according to a first embodiment. Fig. 2 is a cross-sectional view showing an overview of an ammonia co-firing burner according to the first embodiment. Fig. 3 is a cross-sectional view showing an overview of an ammonia co-firing burner according to a second embodiment. Fig. 4 is a cross-sectional view showing an overview of an ammonia co-firing burner according to a third embodiment. Fig. 5 is a cross-sectional view showing an overview of an ammonia co-firing burner according to a fourth embodiment.

[0021] Hereinafter, several exemplary embodiments will be described with reference to the drawings. Note that the dimensional proportions of the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0022] [First embodiment] Fig. 1 shows a boiler 1 included in an ammonia co-firing system according to a first embodiment. As shown in Fig. 1, the boiler 1 includes a combustion chamber 2, a flue 3, an ammonia co-firing burner 4, a two-stage combustion air supply unit 5, an ammonia supply unit 6, a carbon-containing fuel supply unit 7, and an air supply unit 8.

[0023] The combustion chamber 2 is a furnace body that is composed of vertical, cylindrical furnace walls and burns ammonia and a carbon-containing fuel to generate combustion heat. In the combustion chamber 2, high-temperature combustion gas is generated by the combustion of the fuel. In addition, an outlet 2a is provided at the bottom of the combustion chamber 2 to discharge ash generated by the combustion of the fuel to the outside.

[0024] The flue 3 is connected to the upper part of the combustion chamber 2 and guides the combustion gas generated in the combustion chamber 2 to the outside as exhaust gas. The flue 3 includes a horizontal flue 3a extending horizontally from the upper part of the combustion chamber 2 and a rear flue 3b extending downward from the end of the horizontal flue 3a.

[0025] The boiler 1 is equipped with a superheater (not shown) installed above the combustion chamber 2. The superheater generates steam by heat exchange between the combustion heat generated in the combustion chamber 2 and water. The boiler 1 may also be equipped with a reheater, a coal economizer, an air preheater, etc. (none of which are shown) as needed.

[0026] The ammonia-mixed combustion burner 4 is disposed on a wall portion at the bottom of the combustion chamber 2. A plurality of ammonia-mixed combustion burners 4 may be disposed in the circumferential direction of the combustion chamber 2, or a plurality of ammonia-mixed combustion burners 4 may be disposed in the height direction of the combustion chamber 2. These ammonia-mixed combustion burners 4 are disposed two-dimensionally and facing each other at the bottom of the combustion chamber 2, and inject and burn fuel. Each of these ammonia-mixed combustion burners 4 is a combined burner that can inject ammonia and a carbon-containing fuel into the combustion chamber 2. The combustion chamber 2 is provided with an ignition device (not shown) that ignites the ammonia and carbon-containing fuel injected from the ammonia-mixed combustion burner 4. The boiler 1 also has an air supply unit 8 that supplies combustion air to the ammonia-mixed combustion burner 4. The ammonia and carbon-containing fuel injected into the combustion chamber 2 together with the combustion air from the ammonia-mixed combustion burner 4 are ignited and burned by the action of the ignition device.

[0027] It is not necessary that all of the burners installed in the boiler 1 are ammonia-mixed combustion burners 4. For example, the boiler 1 may be provided with a coal-only burner or an ammonia-only burner in addition to the ammonia-mixed combustion burner 4.

[0028] The two-stage combustion air supply unit 5 is connected to the combustion chamber 2 above the ammonia-mixed combustion burner 4, and supplies air for two-stage combustion into the combustion chamber 2. By supplying air for two-stage combustion by the two-stage combustion air supply unit 5, unburned fuel combusted by the ammonia-mixed combustion burner 4 is combusted by the two-stage combustion air, thereby improving the heat absorption performance of the boiler 1 and reducing the unburned fuel contained in the exhaust gas. The combustion gas generated by the combustion of the fuel moves from the bottom to the top of the combustion chamber 2 and is guided to the outside through the flue 3.

[0029] The carbon-containing fuel supplied to the ammonia co-firing burner 4 includes fossil fuel, biomass fuel, synthetic fuel, etc. Examples of fossil fuel include methane, ethane, propane, butane, liquefied natural gas, kerosene, heavy oil, light oil, gasoline, and coal such as pulverized coal. Pulverized coal is coal that has been pulverized to a size of about several micrometers and is commonly used as fuel for boilers.

[0030] On the other hand, examples of biomass fuels include shredded woody biomass such as thinned wood, lumber scraps, and pruned branches, which are produced by a shredder, sawdust, and pellets produced from woody biomass. Synthetic fuels may be hydrocarbons produced by methanation or the Fischer-Tropsch reaction. Carbon-containing fuels can also be used in combination. For example, a mixed powder obtained by mixing pulverized coal with biomass fuel powder can be supplied to the ammonia-mixed combustion burner 4 by air transport.

[0031] Ammonia (NH ３ ) is a compound of hydrogen atoms (H) and nitrogen atoms (N), and does not contain carbon (C) as a constituent atom, so when it is burned, it does not produce CO ２ It is expected that it will be used as a fuel that does not emit CO. ２In order to reduce emissions, technological development is underway to introduce an ammonia co-firing system in which ammonia and coal are mixed and burned by modifying part of existing facilities such as coal-fired power plants. On the other hand, there is concern that the replacement of part of the fuel from coal with ammonia will increase nitrogen oxides (NOx) associated with the combustion of ammonia. Therefore, in this embodiment, NO Ｘ To provide an ammonia co-firing burner with reduced emissions.

[0032] The ammonia supply unit 6 includes an ammonia supply source 6a, a fuel ammonia supply unit 6b, and an ammonia supply control device 6c. The ammonia supply source 6a is composed of a tank for storing ammonia, etc. The ammonia supply source 6a does not necessarily have to be a component of the ammonia supply unit 6. In other words, the ammonia supply unit 6 may take in ammonia from an externally installed ammonia supply source 6a.

[0033] The fuel ammonia supply unit 6b includes a fuel ammonia supply pipe 6b1 that connects the ammonia supply source 6a and the ammonia-mixed combustion burner 4, and a flow rate control valve 6b2 that is installed midway along the fuel ammonia supply pipe 6b1. The fuel ammonia supply pipe 6b1 is a pipe that guides the ammonia supplied from the ammonia supply source 6a to the ammonia-mixed combustion burner 4, and supplies the ammonia to the inside of the combustion chamber 2 via an ammonia supply flow path 42. The flow rate control valve 6b2 is a valve that adjusts the flow rate of ammonia supplied from the ammonia supply source 6a to the fuel ammonia supply pipe 6b1.

[0034] The ammonia supply control device 6c controls the flow rate control valve 6b2 to adjust the aperture of the flow rate control valve 6b2. The ammonia supply control device 6c adjusts the aperture of the flow rate control valve 6b2 based on an external command or the like to adjust the flow rate of ammonia taken in from the ammonia supply source 6a.

[0035] The carbon-containing fuel supply unit 7 is connected to the ammonia-mixed combustion burner 4 and supplies the carbon-containing fuel to the inside of the combustion chamber 2 via the carbon-containing fuel supply passage 41 .

[0036] When the carbon-containing fuel is pulverized coal, the coal is pulverized to form pulverized coal, and the pulverized coal is supplied to the ammonia-mixed combustion burner 4. The carbon-containing fuel supply unit 7 includes, for example, a mill that pulverizes coal to particle sizes of about several micrometers to form pulverized coal, and a coal feeder that supplies the pulverized coal produced by the mill to the ammonia-mixed combustion burner 4. Note that the carbon-containing fuel supply unit 7 may also be configured to supply pulverized coal directly from the mill to the ammonia-mixed combustion burner 4 without including a coal feeder.

[0037] The air supply unit 8 is connected to the middle of the pipe connecting the carbon-containing fuel supply unit 7 and the ammonia-mixed combustion burner 4, and supplies combustion air to the carbon-containing fuel. The air supplied to the carbon-containing fuel is heated by a heating device (not shown) provided upstream of the air supply unit 8, and has a temperature higher than room temperature. The carbon-containing fuel supply passage 41 of the ammonia-mixed combustion burner 4 premixes the carbon-containing fuel and air before combustion and supplies the premixed fuel to the combustion chamber 2.

[0038] The air supply unit 8 is connected to the fuel ammonia supply pipe 6b1 and supplies combustion air to the ammonia. The air supplied to the ammonia is heated by a heating device (not shown) provided upstream of the air supply unit 8 and has a temperature higher than room temperature. The ammonia supply flow path 42 of the ammonia-mixed combustion burner 4 premixes ammonia and air before combustion and supplies the premixed air into the combustion chamber 2.

[0039] As described above, by premixing ammonia and carbon-containing fuel with air before combustion and adjusting the optimal conditions for combustion, the optimal amount of oxygen for each combustion is supplied, and NO Ｘ It is possible to suppress an increase in emissions and unburned fuel in ash. When ammonia and air are mixed in the ammonia supply passage 42, the equivalence ratio between ammonia and air is preferably 1.0 or more, and more preferably 1.1 or more and 2.0 or less. The equivalence ratio indicates the ratio of the amount of fuel actually input to the amount of fuel in the theoretical air-fuel mixture when combustion is performed. An equivalence ratio greater than 1.0 indicates an over-fuel state.

[0040] The ammonia co-firing burner 4 is an ammonia co-firing burner that is installed in the combustion chamber 2 and that supplies and burns ammonia and a carbon-containing fuel into the combustion chamber 2. The ammonia co-firing burner 4 includes a carbon-containing fuel supply passage 41 that mixes the carbon-containing fuel and air and supplies the mixture into the combustion chamber 2, and an ammonia supply passage 42 that mixes the ammonia and air and supplies the mixture into the combustion chamber 2.

[0041] The ammonia-mixed combustion burner 4a according to the first embodiment will be described with reference to Fig. 2. The carbon-containing fuel supply passage 41 in the ammonia-mixed combustion burner 4a is a first injection nozzle 41a that mixes a carbon-containing fuel and air and injects the mixture into the combustion chamber 2. The ammonia supply passage 42 in the ammonia-mixed combustion burner 4a is a second injection nozzle 42a that mixes ammonia and air and injects the mixture into the combustion chamber 2. That is, the ammonia-mixed combustion burner 4a according to the first embodiment includes the first injection nozzle 41a and the second injection nozzle 42a.

[0042] The first injection nozzle 41a may be formed to surround the second injection nozzle 42a and may have a double-cylinder shape concentric with the second injection nozzle 42a. That is, the first injection nozzle 41a may be an outer cylinder and the second injection nozzle 42a may be an inner cylinder, with the nozzle axis L of the second injection nozzle 42a as the center. Furthermore, the injection direction of the first injection nozzle 41a and the injection direction of the second injection nozzle 42a may be oriented in the same direction as the nozzle axis L.

[0043] On the other hand, the ammonia-mixed combustion burner 4a is provided with a secondary air supply passage 43a that supplies air through a swirler 45a into the combustion chamber 2. The secondary air supply passage 43a is disposed so as to surround the outside of the injection port of the first injection nozzle 41a.

[0044] The air supply unit 8 is connected to the secondary air supply passage 43a and supplies secondary air for combustion to the flame from the radially outer side. The secondary air supplied to the combustion chamber 2 via the secondary air supply passage 43a is heated by a heating device (not shown) provided upstream of the air supply unit 8 and has a temperature higher than room temperature.

[0045] The swirler 45a is provided upstream of the secondary air supply passage 43a. The swirler 45a has a plurality of radially arranged blades and a drive device such as a motor for rotating the blades. The rotation of the blades of the swirler 45a finely adjusts the swirling force of the secondary air flowing into the secondary air supply passage 43a. The swirling force of the secondary air then forms an internal circulating flow of fuel and air within the combustion chamber 2. The internal circulating flow is a circulating flow that flows from the outside of the combustion chamber 2 toward the nozzle axis L, as indicated by the dotted lines and arrows in FIG. 2 .

[0046] In the ammonia-mixed combustion burner 4a, ammonia and air are injected from the second injection nozzle 42a, and a carbon-containing fuel and air are injected from the first injection nozzle 41a. Furthermore, in the ammonia-mixed combustion burner 4a, secondary air for combustion is supplied and combusted, thereby forming flames F1 and F2 in front of the ammonia-mixed combustion burner 4a, as shown in FIG.

[0047] The flame F1 is a carbon-containing fuel flame that is burned by injecting a carbon-containing fuel and air from the first injection nozzle 41 a. As described above, the flame F1 is formed radially outward from the nozzle axis L due to the internal circulating flow in the combustion chamber 2 that is generated by the swirling force of the secondary air.

[0048] On the other hand, flame F2 is an ammonia flame produced by combustion of ammonia and air injected from the second injection nozzle 42a. Flame F2 is formed in a linear direction along the nozzle axis L. When flames F1 and F2 are formed in this manner, the outer edge region of flame F1 (the region radially outward from the nozzle axis L) and the tip region of flame F2 become low-oxygen concentration regions where the oxygen concentration is low.

[0049] Ammonia and air are mixed and supplied into the combustion chamber 2 from the second injection nozzle 42a of the ammonia mixed combustion burner 4a, but the ammonia is injected into the oxygen concentration reduced region where the oxygen concentration is low. When ammonia is burned in an oxygen-rich region, the nitrogen contained in the ammonia is likely to combine with oxygen to generate NOx, but when ammonia is burned in an oxygen concentration reduced region, the nitrogen contained in the ammonia is likely to combine with oxygen to generate nitrogen gas (N ２Therefore, the ammonia-mixed combustion burner 4a can suppress an increase in NOx.

[0050] As described above, the ammonia co-firing burner 4a according to the first embodiment includes a first injection nozzle 41a that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber 2, and a second injection nozzle 42a that mixes ammonia and air and injects the mixture into the combustion chamber 2. Therefore, during co-firing, ammonia and carbon-containing fuel are burned in separate spaces, and the combustion of ammonia and carbon-containing fuel does not compete with each other. Furthermore, by premixing a portion of the air with ammonia before combustion and adjusting the optimum conditions for combustion, an optimum amount of oxygen is supplied for each combustion, and NO Ｘ It is possible to suppress the increase in emissions and unburned content in ash.

[0051] [Second embodiment] Next, an ammonia co-firing burner according to a second embodiment will be described. The boiler 1 provided in the ammonia co-firing system shown in Fig. 1 is the same as that of the first embodiment except for the ammonia co-firing burner 4, and therefore a description thereof will be omitted. In the description of the second embodiment, descriptions of the same parts as those of the first embodiment will be omitted or simplified.

[0052] An ammonia-mixed combustion burner 4b according to the second embodiment will be described with reference to Fig. 3. The carbon-containing fuel supply passage 41 in the ammonia-mixed combustion burner 4b is a first injection nozzle 41b that mixes a carbon-containing fuel and air and injects the mixture into the combustion chamber 2. The ammonia supply passage 42 in the ammonia-mixed combustion burner 4b is a second injection nozzle 42b that mixes ammonia and air and injects the mixture into the combustion chamber 2. That is, the ammonia-mixed combustion burner 4b according to the second embodiment includes a first injection nozzle 41b and a second injection nozzle 42b.

[0053] The second injection nozzle 42b may be formed to surround the first injection nozzle 41b and may have a double-cylinder shape concentric with the first injection nozzle 41b. That is, the second injection nozzle 42b may be an outer cylinder and the first injection nozzle 41b may be an inner cylinder, with the nozzle axis L of the first injection nozzle 41b as the center. Furthermore, the injection direction of the first injection nozzle 41b and the injection direction of the second injection nozzle 42b may be oriented in the same direction as the nozzle axis L.

[0054] On the other hand, the ammonia-mixed combustion burner 4b is provided with a secondary air supply passage 43b that supplies air through a swirler 45b into the combustion chamber 2. The secondary air supply passage 43b is disposed so as to surround the outside of the injection port of the second injection nozzle 42b.

[0055] The air supply unit 8 is connected to the secondary air supply passage 43b and supplies secondary air for combustion to the flame from the radially outer side. The secondary air supplied to the combustion chamber 2 via the secondary air supply passage 43b is heated by a heating device (not shown) provided upstream of the air supply unit 8 and has a temperature higher than room temperature.

[0056] The swirler 45b has the same function as the swirler 45a in the first embodiment and is provided upstream of the secondary air supply passage 43b to finely adjust the swirl force of the secondary air flowing into the secondary air supply passage 43b. In the ammonia-mixed combustion burner 4b, carbon-containing fuel and air are injected from the first injection nozzle 41b, and ammonia and air are injected from the second injection nozzle 42b. Furthermore, in the ammonia-mixed combustion burner 4b, secondary air for combustion is supplied and combusted, thereby forming flames F1 and F2 in front of the ammonia-mixed combustion burner 4b, as shown in FIG. 3.

[0057] Flame F2 is an ammonia flame produced by combustion of ammonia and air injected from the second injection nozzle 42b. Due to an internal circulating flow (dotted lines and arrows in FIG. 3 ) in the combustion chamber 2 generated by the swirling force of the secondary air, flame F2 is formed radially outward from the nozzle axis L. On the other hand, flame F1 is a carbon-containing fuel flame produced by combustion of carbon-containing fuel and air injected from the first injection nozzle 41b, and is formed linearly along the nozzle axis L. When flames F1 and F2 are formed in this manner, the outer edge region of flame F2 (the region radially outward from the nozzle axis L) and the tip region of flame F1 become low-oxygen concentration regions where the oxygen concentration is low.

[0058] Ammonia and air are mixed and supplied from the second injection nozzle 42b of the ammonia-mixed combustion burner 4b into the combustion chamber 2, and the ammonia is injected into the low-oxygen concentration region where the oxygen concentration is low. Therefore, as in the first embodiment, the ammonia-mixed combustion burner 4b can suppress an increase in nitrogen oxides (NOx).

[0059] As described above, the ammonia co-firing burner 4b according to the second embodiment includes a first injection nozzle 41b that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber 2, and a second injection nozzle 42b that mixes ammonia and air and injects the mixture into the combustion chamber 2. Therefore, during co-firing, ammonia and carbon-containing fuel are burned in separate spaces, and the combustion of ammonia and carbon-containing fuel does not compete with each other. Furthermore, by premixing a portion of the air with ammonia before combustion and adjusting the optimum conditions for combustion, an optimum amount of oxygen is supplied for each combustion, and NO Ｘ It is possible to suppress the increase in emissions and unburned content in ash.

[0060] [Third embodiment] Next, an ammonia co-firing burner according to a third embodiment will be described. The boiler 1 provided in the ammonia co-firing system shown in Fig. 1 is the same as that of the first embodiment except for the ammonia co-firing burner 4, and therefore a description thereof will be omitted. In the description of the third embodiment, descriptions of the same parts as those of the above-mentioned embodiments will be omitted or simplified.

[0061] An ammonia-mixed combustion burner 4c according to the third embodiment will be described with reference to Fig. 4. The carbon-containing fuel supply passage 41 in the ammonia-mixed combustion burner 4c is a first injection nozzle 41c that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber 2. The ammonia supply passage 42 in the ammonia-mixed combustion burner 4c is an ammonia supply passage 42c that mixes ammonia and secondary air and supplies the mixture into the combustion chamber 2. That is, the ammonia-mixed combustion burner 4c according to the third embodiment includes a first injection nozzle 41c and an ammonia supply passage 42c.

[0062] The ammonia-mixed combustion burner 4c includes an air injection nozzle 46c that injects combustion air into the combustion chamber 2. The air supply unit 8 is connected to the air injection nozzle 46c. The air injected into the combustion chamber 2 via the air injection nozzle 46c is heated by a heating device (not shown) provided upstream of the air supply unit 8, and is at a temperature higher than room temperature. The air injection nozzle 46c may be formed to surround the first injection nozzle 41c and be concentric with the first injection nozzle 41c. That is, the air injection nozzle 46c may be a double-cylinder shape with the air injection nozzle 46c as the outer cylinder and the first injection nozzle 41c as the inner cylinder, with the nozzle axis L of the first injection nozzle 41c as the center. Furthermore, the injection direction of the first injection nozzle 41c and the injection direction of the air injection nozzle 46c may be oriented in the same direction as the nozzle axis L.

[0063] On the other hand, the ammonia-mixed combustion burner 4c includes an ammonia supply passage 42c that mixes ammonia and secondary air through a swirler 45c and supplies the mixture into the combustion chamber 2. The ammonia supply passage 42c is disposed so as to surround the outside of the outlet of the air injection nozzle 46c.

[0064] The air supply unit 8 is connected to the ammonia supply passage 42c and supplies secondary air for combustion to the flame from the radially outer side. The secondary air supplied to the combustion chamber 2 via the ammonia supply passage 42c is heated by a heating device (not shown) provided upstream of the air supply unit 8 and has a temperature higher than room temperature.

[0065] The swirler 45c has the same function as the swirler 45a of the first embodiment, is provided upstream of the ammonia supply passage 42c, and finely adjusts the swirling force of the secondary air flowing into the ammonia supply passage 42c. In the ammonia co-firing burner 4c, a carbon-containing fuel and air are injected from the first injection nozzle 41c, and combustion air is injected. Furthermore, in the ammonia co-firing burner 4c, ammonia and secondary air are supplied from the ammonia supply passage 42c, and thereby flames F1 and F2 are formed in front of the ammonia co-firing burner 4c, as shown in FIG. 4 .

[0066] Flame F2 is an ammonia flame produced by combustion using ammonia and secondary air supplied from the ammonia supply passage 42c. Due to an internal circulating flow (dotted lines and arrows in FIG. 4 ) in the combustion chamber 2 generated by the swirling force of the secondary air, flame F2 is formed radially outward from the nozzle axis L. On the other hand, flame F1 is a carbon-containing fuel flame produced by combustion using carbon-containing fuel and air injected from the first injection nozzle 41c, and is formed linearly along the nozzle axis L. When flames F1 and F2 are formed in this manner, the outer edge region of flame F2 (the region radially outward from the nozzle axis L) and the tip region of flame F1 become low-oxygen concentration regions where the oxygen concentration is low.

[0067] Ammonia and secondary air are mixed and supplied from the ammonia supply passage 42c of the ammonia-mixed combustion burner 4c into the combustion chamber 2, and the ammonia is injected into the low oxygen concentration region where the oxygen concentration is low. Therefore, as in the first embodiment, the ammonia-mixed combustion burner 4c can suppress an increase in NOx.

[0068] As described above, the ammonia co-firing burner 4c according to the third embodiment includes a first injection nozzle 41c that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber 2, and an ammonia supply passage 42c that mixes ammonia and air and supplies the mixture into the combustion chamber 2. Therefore, during co-firing, the ammonia and the carbon-containing fuel are burned in separate spaces, and the combustion of the ammonia and the carbon-containing fuel does not compete with each other. Furthermore, by premixing a portion of the air with the ammonia before combustion and adjusting the optimum conditions for combustion, the optimum amount of oxygen is supplied for each combustion, and NOＸ It is possible to suppress the increase in emissions and unburned content in ash.

[0069] [Fourth embodiment] Next, an ammonia co-firing burner according to a fourth embodiment will be described. The boiler 1 provided in the ammonia co-firing system shown in Fig. 1 is the same as that of the first embodiment except for the ammonia co-firing burner 4, and therefore a description thereof will be omitted. In the description of the fourth embodiment, descriptions of the same parts as those of the above-mentioned embodiments will be omitted or simplified.

[0070] An ammonia-mixed combustion burner 4d according to the fourth embodiment will be described with reference to Fig. 5. The carbon-containing fuel supply passage 41 in the ammonia-mixed combustion burner 4d is a first injection nozzle 41d that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber 2. The ammonia supply passage 42 in the ammonia-mixed combustion burner 4d is an ammonia supply passage 42d that mixes ammonia and air and supplies the mixture into the combustion chamber 2. That is, the ammonia-mixed combustion burner 4d according to the fourth embodiment includes a first injection nozzle 41d and an ammonia supply passage 42d.

[0071] The ammonia mixed combustion burner 4d includes an ammonia injection nozzle 47d that injects ammonia into the combustion chamber 2. The above-mentioned ammonia fuel supply pipe 6b1 is connected to the ammonia injection nozzle 47d. The first injection nozzle 41d may be formed to surround the ammonia injection nozzle 47d and may have a double-cylinder shape that is concentric with the ammonia injection nozzle 47d. That is, the first injection nozzle 41d may be an outer cylinder and the ammonia injection nozzle 47d may be an inner cylinder, with the nozzle axis L of the ammonia injection nozzle 47d as the center. Furthermore, the injection direction of the first injection nozzle 41d and the injection direction of the ammonia injection nozzle 47d may be oriented in the same direction as the nozzle axis L.

[0072] On the other hand, the ammonia-mixed combustion burner 4d includes an ammonia supply passage 42d that mixes ammonia and secondary air through a swirler 45d and supplies the mixture into the combustion chamber 2. The ammonia supply passage 42d is disposed so as to surround the outside of the injection port of the first injection nozzle 41d.

[0073] The air supply unit 8 is connected to the ammonia supply passage 42d and supplies secondary air for combustion to the flame from the radially outer side. The secondary air supplied into the combustion chamber 2 via the ammonia supply passage 42d is heated by a heating device (not shown) provided upstream of the air supply unit 8 and has a temperature higher than room temperature.

[0074] The swirler 45d has the same function as the swirler 45a of the first embodiment, is provided upstream of the ammonia supply passage 42d, and finely adjusts the swirling force of the secondary air flowing into the ammonia supply passage 42d.

[0075] Furthermore, the ammonia-mixed combustion burner 4d is equipped with a tertiary air supply passage 44d arranged to surround the ammonia supply passage 42d. The tertiary air supply passage 44d supplies tertiary air for combustion to the flame from the radially outer side. A swirler 45e is provided upstream of the ammonia supply passage 42d and the tertiary air supply passage 44d. The swirler 45e finely adjusts the swirling force of the secondary air flowing into the ammonia supply passage 42d and the tertiary air flowing into the tertiary air supply passage 44d.

[0076] In the ammonia-mixed combustion burner 4d, ammonia is injected from an ammonia injection nozzle 47d, and a carbon-containing fuel and air are injected from a first injection nozzle 41d. Furthermore, in the ammonia-mixed combustion burner 4d, ammonia and secondary air are supplied from an ammonia supply passage 42d, and tertiary air for combustion is supplied, whereby flames F1 and F2 are formed in front of the ammonia-mixed combustion burner 4d, as shown in FIG.

[0077] Flame F2 is an ammonia flame produced by combustion when ammonia is injected from the ammonia injection nozzle 47d or when ammonia and secondary air are injected from the ammonia supply passage 42d. Flame F2 produced by combustion when ammonia is injected from the ammonia injection nozzle 47d is formed in a linear direction along the nozzle axis L. On the other hand, flame F2 produced by combustion when ammonia is injected from the ammonia supply passage 42d is formed radially outward from the nozzle axis L by an internal circulating flow (dotted lines and arrows in FIG. 5 ) in the combustion chamber 2 that is generated by the swirling force of the secondary air and tertiary air.

[0078] On the other hand, the flame F1 is a carbon-containing fuel flame that is burned by injecting the carbon-containing fuel and air from the first injection nozzle 41 d. The flame F1 is formed by the internal circulating flow in the combustion chamber 2 toward the radially outward direction of the nozzle axis L, at a position where it is sandwiched between the flames F2.

[0079] When flames F1 and F2 are formed in this manner, the outer edge region of flame F2 (the region radially outward from nozzle axis L) and the tip regions of flames F1 and F2 become low oxygen concentration regions where the oxygen concentration is low.

[0080] Ammonia is supplied into the combustion chamber 2 from the ammonia injection nozzle 47d and the ammonia supply passage 42d of the ammonia-mixed combustion burner 4d, and the ammonia is injected into the low-oxygen concentration region where the oxygen concentration is low. Therefore, similar to the first embodiment, the ammonia-mixed combustion burner 4d can suppress an increase in NOx.

[0081] As described above, the ammonia co-firing burner 4d according to the fourth embodiment includes a first injection nozzle 41d that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber 2, and an ammonia supply passage 42d that mixes ammonia and air and supplies the mixture into the combustion chamber 2. Therefore, during co-firing, the ammonia and the carbon-containing fuel are burned in separate spaces, and the combustion of the ammonia and the carbon-containing fuel does not compete with each other. Furthermore, by premixing a portion of the air with the ammonia before combustion and adjusting the optimum conditions for combustion, the optimum amount of oxygen is supplied for each combustion, and NO Ｘ It is possible to suppress the increase in emissions and unburned content in ash.

[0082] As described above, the ammonia co-firing burner is installed in a combustion chamber, and supplies ammonia and a carbon-containing fuel into the combustion chamber for combustion. The ammonia co-firing burner is equipped with a carbon-containing fuel supply passage or a first injection nozzle that mixes the carbon-containing fuel and air and supplies the mixture into the combustion chamber, and an ammonia supply passage or a second injection nozzle that mixes the ammonia and air and supplies the mixture into the combustion chamber. Therefore, during co-firing, the ammonia and the carbon-containing fuel are burned in separate spaces, and there is no competition between the combustion of the ammonia and the combustion of the carbon-containing fuel. Furthermore, by premixing a portion of the air with the ammonia before combustion and adjusting the optimal conditions for combustion, an optimal amount of oxygen is supplied for each combustion, and NO Ｘ It is possible to suppress the increase in emissions and unburned content in ash.

[0083] The ammonia co-firing system includes a combustion chamber and an ammonia co-firing burner that supplies ammonia and a carbon-containing fuel into the combustion chamber and burns them. A method for manufacturing such an ammonia co-firing system does not necessarily require new construction of each facility; instead, manufacturing costs can be reduced by modifying existing facilities, such as pulverized coal burners. For example, an existing pulverized coal burner can be modified by connecting a connecting passage to a secondary air supply passage that supplies secondary air into the combustion chamber, thereby installing an ammonia supply passage that mixes ammonia and air and supplies the mixture into the combustion chamber. Furthermore, the injection nozzle of an existing pulverized coal burner that injects fuel or air into the combustion chamber can be replaced with a second injection nozzle that mixes ammonia and air and injects the mixture into the combustion chamber.

[0084] [Manufacturing Method 1 of Ammonia Co-firing System] In one manufacturing method, for example, a burner equipped with a first injection nozzle that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber is modified. Specifically, the burner is modified by connecting a connecting path to a secondary air supply passage that supplies air into the combustion chamber, and ammonia is supplied to the secondary air supply passage. The secondary air passage is then replaced with an ammonia supply passage that mixes ammonia and air and supplies the mixture into the combustion chamber. In this manner, an ammonia supply passage is installed in the ammonia co-firing burner. Furthermore, a swirler is installed in the ammonia supply passage. The modified ammonia co-firing burner includes a first injection nozzle and an ammonia supply passage. Note that the air injection nozzle may be formed to surround the first injection nozzle and be concentric with the first injection nozzle, forming a double-cylinder shape. In this manner, the ammonia co-firing burner 4c according to the third embodiment ( FIG. 4 ) can be manufactured.

[0085] The air supply passage may be divided into multiple air supply passages, and at least some of the multiple air supply passages may be modified by connecting a connecting passage to provide an ammonia supply passage that mixes ammonia and air and supplies the mixture to the combustion chamber. For example, the secondary air supply passage that supplies air to the combustion chamber may be divided into a secondary air supply passage and a tertiary air supply passage, and then modified by connecting a connecting passage to the secondary air supply passage to supply ammonia to the secondary air supply passage. In this manner, the secondary air supply passage is replaced with an ammonia supply passage that mixes ammonia and air and supplies the mixture to the combustion chamber. Meanwhile, the tertiary air supply passage supplies tertiary air to the combustion chamber. Furthermore, by installing swirlers upstream of the ammonia supply passage and the tertiary air supply passage, an ammonia supply passage and a tertiary air supply passage can be provided, similar to the ammonia supply passage 42d and the tertiary air supply passage 44d of the fourth embodiment ( FIG. 5 ).

[0086] [Manufacturing Method 2 of Ammonia Co-firing System] As a manufacturing method, for example, a burner having a double-cylinder shape is modified, in which a first injection nozzle that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber surrounds the ammonia injection nozzle that injects ammonia into the combustion chamber, and the first injection nozzle is arranged concentrically with the ammonia injection nozzle. Specifically, the burner is modified by connecting a connecting path to a secondary air supply passage that supplies air into the combustion chamber, and ammonia is supplied to the secondary air supply passage. The secondary air supply passage is then replaced with an ammonia supply passage that mixes ammonia and air and supplies the mixture into the combustion chamber. In this way, an ammonia supply passage is installed in the ammonia co-firing burner. Furthermore, a swirler is installed in the ammonia supply passage. The modified ammonia co-firing burner includes a first injection nozzle and an ammonia supply passage.

[0087] The air supply passage may be divided into a plurality of air supply passages, and at least some of the plurality of air supply passages may be modified by connecting a connecting passage to provide an ammonia supply passage that mixes ammonia and air and supplies the mixture to the combustion chamber. For example, the secondary air supply passage may be replaced with an ammonia supply passage, while the tertiary air supply passage supplies tertiary air to the combustion chamber. Furthermore, by providing a swirler upstream of the ammonia supply passage and the tertiary air supply passage, the ammonia-mixed combustion burner 4d according to the fourth embodiment (FIG. 5) can be manufactured.

[0088] [Manufacturing Method 3 for Ammonia Co-firing System] In one manufacturing method, for example, a double-cylinder burner is modified, in which a first injection nozzle that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber surrounds the ammonia injection nozzle that injects ammonia into the combustion chamber, and the first injection nozzle is arranged concentrically with the ammonia injection nozzle. Specifically, the burner is modified by connecting a connecting path to the ammonia injection nozzle, and air is supplied to the ammonia supply flow path. The ammonia injection nozzle is then replaced with a second injection nozzle that mixes ammonia and air and supplies the mixture into the combustion chamber. In this way, the second injection nozzle is installed in the ammonia co-firing burner. The modified ammonia co-firing burner includes the first injection nozzle and the second injection nozzle.

[0089] The injection direction of the first injection nozzle and the injection direction of the second injection nozzle may be oriented in the same direction as the nozzle axis. Also, a swirler may be installed in the secondary air supply passage, and a secondary air supply passage may be installed that supplies air into the combustion chamber through the swirler. This allows the ammonia-mixed combustion burner 4a according to the first embodiment (FIG. 2) to be manufactured.

[0090] [Manufacturing Method 4 of Ammonia Co-firing System] In the manufacturing method, for example, a burner equipped with a first injection nozzle that mixes carbon-containing fuel and air and injects the mixture into the combustion chamber is modified. Specifically, the burner is modified by installing a second injection nozzle that mixes ammonia and air and injects the mixture into the combustion chamber outside the first injection nozzle. The modified ammonia co-firing burner is equipped with the first injection nozzle and the second injection nozzle.

[0091] The second injection nozzle may be formed to surround the first injection nozzle and have a double-cylinder shape concentric with the first injection nozzle. The injection directions of the first injection nozzle and the second injection nozzle may be aligned in the same direction as the nozzle axis. A swirler may be installed in the secondary air supply passage, and a secondary air supply passage may be provided that supplies air into the combustion chamber through the swirler. This allows the ammonia-mixed combustion burner 4b according to the second embodiment ( FIG. 3 ) to be manufactured.

[0092] As described above, the ammonia co-firing burner according to this embodiment is installed in a combustion chamber, and supplies ammonia and a carbon-containing fuel into the combustion chamber for combustion. The ammonia co-firing burner includes a carbon-containing fuel supply passage that mixes the carbon-containing fuel and air and supplies the mixture into the combustion chamber, and an ammonia supply passage that mixes the ammonia and air and supplies the mixture into the combustion chamber. The ammonia co-firing system also includes a combustion chamber and an ammonia co-firing burner that supplies ammonia and a carbon-containing fuel into the combustion chamber and burns them. Therefore, a method for manufacturing the ammonia co-firing system can reduce manufacturing costs by modifying existing equipment such as a pulverized coal burner.

[0093] Although several embodiments have been described, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they contradict each other.

[0094] This disclosure can contribute, for example, to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy for all" and Goal 13, "Take urgent action to combat climate change and its impacts."

[0095] The entire contents of Japanese Patent Application No. 2023-132239 (filing date: August 15, 2023) are incorporated herein by reference.

[0096] REFERENCE SIGNS LIST 1 Boiler 2 Combustion chamber 4, 4a, 4b, 4c, 4d Ammonia mixed combustion burner 41 Carbon-containing fuel supply passage 41a, 41b, 41c, 41d First injection nozzle (carbon-containing fuel supply passage) 42, 42c, 42d Ammonia supply passage 42a, 42b Second injection nozzle (ammonia supply passage) 43a, 43b Secondary air supply passage (air supply passage) 45a, 45b, 45c, 45d, 45e Swirler

Claims

1. An ammonia-mixed combustion burner that is installed in a combustion chamber and supplies ammonia and a carbon-containing fuel into the combustion chamber to burn them, the ammonia-mixed combustion burner comprising: a carbon-containing fuel supply flow path that mixes the carbon-containing fuel and air and supplies the mixture into the combustion chamber; and an ammonia supply flow path that mixes the ammonia and air and supplies the mixture into the combustion chamber.

2. The ammonia co-fuel burner according to claim 1, wherein the carbon-containing fuel supply passage is a first injection nozzle that mixes a carbon-containing fuel and air and injects the mixture into the combustion chamber, and the ammonia supply passage is a second injection nozzle that mixes ammonia and air and injects the mixture into the combustion chamber.

3. The ammonia-mixed combustion burner according to claim 2, wherein the first injection nozzle is formed to surround the second injection nozzle and has a double cylindrical shape arranged concentrically with the second injection nozzle, the injection direction of the first injection nozzle and the injection direction of the second injection nozzle are oriented in the same direction as a nozzle axis line, and the burner is provided with an air supply flow path that supplies air into the combustion chamber through a swirler.

4. The ammonia-mixed combustion burner according to claim 2, wherein the second injection nozzle is formed so as to surround the first injection nozzle and has a double-cylinder shape arranged concentrically with the first injection nozzle, the injection direction of the first injection nozzle and the injection direction of the second injection nozzle are oriented in the same direction as a nozzle axis line, and the burner is provided with an air supply flow path for supplying air into the combustion chamber through a swirler.

5. The ammonia-mixed combustion burner according to any one of claims 1 to 4, wherein an equivalence ratio of ammonia to air when ammonia and air are mixed in the ammonia supply passage is 1.0 or more.

6. A method for manufacturing an ammonia co-combustion system having a combustion chamber and an ammonia co-combustion burner for supplying ammonia and a carbon-containing fuel into the combustion chamber and combusting them, the method comprising modifying the burner, which is equipped with a first injection nozzle for mixing the carbon-containing fuel and air and injecting the mixture into the combustion chamber, by connecting a connecting path to an air supply flow path for supplying air into the combustion chamber, and installing an ammonia supply flow path for mixing the ammonia and air and supplying the mixture into the combustion chamber, and a swirler in the ammonia supply flow path.

7. A method for manufacturing an ammonia co-combustion system having a combustion chamber and an ammonia co-combustion burner for supplying ammonia and a carbon-containing fuel into the combustion chamber and burning them, wherein a first injection nozzle for mixing the carbon-containing fuel and air and injecting the mixture into the combustion chamber is formed to surround the ammonia injection nozzle for injecting ammonia into the combustion chamber, and the burner has a double-cylinder shape concentrically arranged with the ammonia injection nozzle, and is modified by connecting a connecting path to an air supply flow path for supplying air into the combustion chamber, and an ammonia supply flow path for mixing ammonia and air and supplying the mixture into the combustion chamber, and a swirler is installed in the ammonia supply flow path.

8. The method for producing an ammonia co-firing system according to claim 6 or 7, wherein the air supply passage is partitioned into a plurality of air supply passages, and the ammonia supply passage is modified by connecting the connecting path to at least a portion of the plurality of air supply passages, thereby providing the ammonia supply passage that mixes ammonia and air and supplies the ammonia and air into the combustion chamber.

9. A method for manufacturing an ammonia co-combustion system having: a combustion chamber; and an ammonia co-combustion burner for supplying ammonia and a carbon-containing fuel into the combustion chamber and combusting them, the method comprising the steps of modifying the burner, which has a double-cylinder shape, and which is concentric with the ammonia injection nozzle, and modifying the burner by connecting a connection path to the ammonia injection nozzle, and installing a second injection nozzle that mixes ammonia and air and supplies the mixture into the combustion chamber, wherein a first injection nozzle that mixes the carbon-containing fuel and air and injects the mixture into the combustion chamber is formed to surround the ammonia injection nozzle that injects ammonia into the combustion chamber and is concentric with the ammonia injection nozzle.

10. The method for producing an ammonia co-firing system according to claim 9, wherein the injection direction of the first injection nozzle and the injection direction of the second injection nozzle are oriented in the same direction as a nozzle axis line, and an air supply flow passage is provided to supply air through a swirler into the combustion chamber.

11. A method for manufacturing an ammonia co-combustion system having a combustion chamber and an ammonia co-combustion burner that supplies ammonia and a carbon-containing fuel into the combustion chamber and combusts them, comprising modifying a burner that is equipped with a first injection nozzle that mixes ammonia and air and injects the mixture into the combustion chamber by installing a second injection nozzle that mixes ammonia and air and injects the mixture into the combustion chamber outside the first injection nozzle.

12. A method for producing an ammonia co-firing system as described in claim 11, wherein the second injection nozzle is formed to surround the first injection nozzle and has a double cylindrical shape concentrically arranged with the first injection nozzle, the injection direction of the first injection nozzle and the injection direction of the second injection nozzle are oriented in the same direction as a nozzle axis line, and an air flow path is provided to supply air into the combustion chamber through a swirler.

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