Combustor and combusting method

Abstract

To decrease unburnt ammonia when ammonia is used as fuel.SOLUTION: A combustor 20 comprises: a flow passage 21a of fuel including ammonia; a burner 21 that includes a tip 21c opposing a space S in a furnace 1 and injects fuel into the furnace 1; and a catalyst C that is disposed upstream relative to the tip 21c in the flow passage 21a.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to combustors and methods of combustion. [Background technology]

[0002] In the combustor, a catalyst may be used to promote combustion. For example, Patent Document 1 discloses a burner section of a gas turbine. A fuel mixture including natural gas and air flows through the burner section. The burner section includes a catalytic burner. The burner section also includes a preconditioning stage provided upstream of the catalytic burner. The preconditioning stage includes a rare metal-containing catalyst. The preconditioning stage is preceded by a heat exchanger to increase the efficiency of the catalyst. In the preconditioning stage, substances such as methanol, aldehydes, and hydrogen, which are relatively easy to ignite, are produced from the natural gas. The fuel mixture is catalytically combusted in the catalytic burner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-509307 Summary of the Invention [Problem to be solved by the invention]

[0004] Ammonia is known as a fuel that does not emit CO2. However, the burning rate of ammonia is slower than other fuels such as natural gas. Therefore, when using ammonia in a combustor, unburned ammonia can be a problem.

[0005] The present disclosure aims to provide a combustor and a combustion method that can reduce unburned ammonia when ammonia is used as fuel. [Means for solving the problem]

[0006] A combustor according to one aspect of the present disclosure includes a flow path for a fuel containing ammonia and a tip facing a space within a furnace, the combustor comprising a burner that injects the fuel into the furnace, and a catalyst disposed in the flow path upstream from the tip.

[0007] The burner may include a regulator to adjust the position of the catalyst in the flow path.

[0008] The burner may include a heat sink disposed at the tip and facing the space within the furnace.

[0009] The burner may include a body that defines a flow passage, and a holder that is removable from the body and that holds the catalyst.

[0010] The tip may be formed of metal and may protect the catalyst from the environment within the furnace.

[0011] The combustor may be a radiant cup burner with a burner tile that holds the burner.

[0012] Another aspect of the present disclosure is a method of combustion comprising: burning in a furnace a first fuel having a burning rate faster than ammonia, the first fuel being injected from at least one first combustor; and burning in the furnace a second fuel including ammonia, the second fuel being injected from at least one second combustor, the at least one second combustor including a flow path for the second fuel and a tip facing a space within the furnace, the at least one second combustor including a burner for injecting the second fuel into the furnace, and a catalyst disposed in the flow path upstream from the tip.

[0013] The combustion method may include adjusting the temperature of the catalyst by adjusting the position of the catalyst in the flow passage.

[0014] The burner of the second combustor may include a heat sink disposed at a tip and exposed to the furnace interior.

[0015] The at least one first combustor may include a plurality of first combustors, and the at least one second combustor may be surrounded by the plurality of first combustors.

[0016] The at least one first combustor and the at least one second combustor may be positioned opposite one another within the furnace.

[0017] The burner of the second combustor may include a body that defines a flow passage, and a holder that is removable from the body and that holds the catalyst.

[0018] The burner tip of the secondary combustor may be formed of metal and may protect the catalyst from the environment within the furnace. Effect of the Invention

[0019] According to the present disclosure, it is possible to reduce unburned ammonia when ammonia is used as fuel. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic cross-sectional view of a boiler including a combustor according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an example of an arrangement of combustors as viewed in the vertical direction. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing another example of the arrangement of combustors as viewed from the vertical direction. [Figure 4] FIG. 4 is a schematic cross-sectional view showing another example of the arrangement of combustors as viewed from the horizontal direction. [Diagram 5] FIG. 5 is a schematic enlarged view of part A in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a combustor according to the second embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a combustor according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating 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 given the same reference numerals to avoid repeated explanations, and elements not directly related to the present disclosure are omitted from the drawings.

[0022] FIG. 1 is a schematic cross-sectional view of a boiler 100 including a combustor 20 according to a first embodiment. In this embodiment, the combustor (second combustor) 20 is applied to the boiler 100. In other embodiments, the combustor 20 may be applied to other combustion facilities such as an industrial furnace or a combustion furnace. For example, the boiler 100 includes a furnace 1, a flue 2, a plurality of first combustors 10, and a plurality of second combustors 20. FIG. 1 shows only one first combustor 10 and one second combustor 20. The boiler 100 may further include other components.

[0023] The furnace 1 burns a fuel containing ammonia to generate combustion gas. For example, the furnace 1 uses multiple fuels including ammonia and other fuels such as pulverized coal. The furnace 1 may also burn only ammonia if desired. The furnace 1 may also burn fuels that do not contain ammonia if desired.

[0024] The furnace 1 extends vertically. The lower part of the furnace 1 defines a combustion space S. In this disclosure, the combustion space means a space in which fuel is burned. An exhaust port Ex is provided at the bottom of the furnace 1. The exhaust port Ex exhausts ash generated by combustion to the outside.

[0025] The flue 2 is a passage that guides the combustion gas generated in the furnace 1 to the outside. The flue 2 is connected to the upper part of the furnace 1. For example, the flue 2 includes a first flue 2a and a second flue 2b. The first flue 2a extends horizontally from the upper part of the furnace 1. The second flue 2b extends downward from the end of the first flue 2a.

[0026] For example, the boiler 100 includes a superheater (not shown) installed on the upper part of the furnace 1. The superheater exchanges heat between the combustion gas generated in the furnace 1 and water. This generates steam. For example, the boiler 100 may further include components (not shown) such as a reheater, a coal economizer, or an air preheater.

[0027] The first combustor 10 and the second combustor 20 are provided on the lower wall of the furnace 1. The first combustor 10 and the second combustor 20 are spaced apart from each other in the horizontal direction along the wall of the furnace 1. Although Fig. 1 shows a single row of combustors 10, 20 in the vertical direction, multiple rows of combustors 10, 20 may be spaced apart from each other in the vertical direction.

[0028] The first combustor 10 injects a first fuel into the combustion space S. The first combustor 10 uses a first fuel, such as pulverized coal, having a faster combustion speed than ammonia. A flame F is formed in the combustion space S by igniting the first fuel injected from the first combustor 10. The furnace 1 is provided with an ignition device (not shown) that ignites the first fuel injected from the first combustor 10. Details of the first combustor 10 will be omitted.

[0029] The second combustor 20 injects the second fuel into the combustion space S. The second combustor 20 uses the second fuel containing ammonia. The second fuel may contain other fuels in addition to ammonia. A flame F is formed in the combustion space S by igniting the second fuel injected from the second combustor 20. The furnace 1 is provided with an ignition device (not shown) that ignites the second fuel injected from the second combustor 20.

[0030] FIG. 2 is a schematic cross-sectional view showing an example of an arrangement of combustors 10, 20 as viewed from a vertical direction. FIG. 2 and the following FIG. 3 show schematic cross-sectional views taken along line II-II in FIG. 1. In FIG. 2 and FIG. 3, the arrangement of the multiple first combustors 10 and the multiple second combustors 20 is seen from above. In FIG. 2 and FIG. 3, the second combustor 20 is indicated by hatching for better understanding.

[0031] As described above, the first combustor 10 and the second combustor 20 are arranged in a horizontal direction spaced apart from each other along the wall of the furnace 1. In FIG. 2, the first combustors 10 and the second combustors 20 are arranged alternately along the wall of the furnace 1. In FIG. 2, rows of the first combustors 10 and the second combustors 20 are provided on opposing walls of the furnace 1. In FIG. 2, the first combustors 10 and the second combustors 20 are arranged to be opposite each other in the horizontal direction. In another expression, in FIG. 2, the first combustors 10 and the second combustors 20 on opposing walls of the furnace 1 are arranged in a zigzag pattern.

[0032] Fig. 3 is a schematic cross-sectional view showing another example of the arrangement of the combustors 10 and 20 as viewed from the vertical direction. In Fig. 3, the first combustor 10 is arranged to face the other first combustor 10, and the second combustor 20 is arranged to face the other second combustor 20 in the horizontal direction.

[0033] Fig. 4 is a schematic cross-sectional view showing an example of an arrangement of combustors 10, 20 as viewed from a horizontal direction. Fig. 4 shows a schematic cross-sectional view taken along line IV-IV in Fig. 2. In Fig. 4, the arrangement of the multiple first combustors 10 and the multiple second combustors 20 is viewed from the side. In Fig. 4, the second combustors 20 are indicated by hatching for better understanding.

[0034] As described above, the multiple first combustors 10 and the multiple second combustors 20 are arranged spaced apart from each other in the horizontal and vertical directions. In FIG. 4, the first combustors 10 and the second combustors 20 are arranged alternately along the wall of the furnace 1. In another expression, in FIG. 4, the first combustors 10 and the second combustors 20 are arranged in a staggered manner along the wall of the furnace 1. According to such a configuration, one second combustor 20 is surrounded by four first combustors 10 from above, below, right, and left. In other examples, the first combustors 10 and the second combustors 20 may be arranged in other patterns. For example, the first combustors 10 and the second combustors 20 may be arranged in a pattern such that one second combustor 20 is surrounded by eight first combustors 10 from above, below, right, left, upper right, lower right, upper left, and lower left.

[0035] Fig. 5 is a schematic enlarged view of part A in Fig. 1. For example, in this embodiment, the second combustor 20 includes a burner 21, an oxidant passage 22, and a control device 90. The second combustor 20 may further include other components.

[0036] The burner 21 has a generally cylindrical shape. In this disclosure, the axial direction, radial direction, and circumferential direction of the burner 21 may be simply referred to as the "axial direction," the "radial direction," and the "circumferential direction," unless otherwise specified. The same applies to the burners 42 (described later) according to the second and third embodiments.

[0037] For example, the burner 21 is attached to the wall of the furnace 1 outside the furnace 1. The burner 21 faces the combustion space S. The burner 21 injects a second fuel containing ammonia into the combustion space S. The burner 21 includes a first flow path 21a for ammonia. Also, for example, the burner 21 may further include a second flow path 21b for an oxidizer (for example, air). For example, the first flow path 21a may extend on the central axis of the burner 21. For example, the second flow path 21b may be disposed around the first flow path 21a. For example, the second flow path 21b may be continuous in the circumferential direction.

[0038] For example, a valve V1 may be provided in an ammonia line L1 connected to the first flow path 21a. The valve V1 may be connected to a control device 90 so as to be capable of communicating with the control device 90 via wire or wirelessly, and may be controlled by the control device 90. For example, the control device 90 adjusts the flow rate of ammonia supplied to the burner 21 by controlling the opening degree of the valve V1.

[0039] For example, a valve V2 may be provided in the oxidant line L2 connected to the second flow path 21b. The valve V2 may be connected to the control device 90 so as to be capable of communicating with the control device 90 via wire or wirelessly, and may be controlled by the control device 90. For example, the control device 90 adjusts the flow rate of the oxidant supplied to the burner 21 by controlling the opening degree of the valve V2.

[0040] The tip 21c of the burner 21 includes an injection hole 21d. The tip 21c and the injection hole 21d face the combustion space S. The injection hole 21d injects the second fuel and the oxidizer into the combustion space S.

[0041] A catalyst C is disposed in the first flow path 21a. The catalyst C is disposed upstream of the tip 21c in the flow of ammonia. For example, the catalyst C includes a transition element (which may also be referred to as a transition metal). For example, the catalyst C may include a precious metal such as Ru. Also, for example, the catalyst C may include a non-precious metal such as Fe, Co, Ni, or Cu among the transition elements. The non-precious metal may exhibit high activity when combined with a specific carrier. For example, an oxide such as Al2O3 or SiO2 may be used as the carrier. Also, a carrier capable of suppressing sintering such as CeO2 may be used as necessary.

[0042] The burner 21 includes an adjuster 30 that adjusts the position of the catalyst C in the first flow passage 21a. The adjuster 30 includes, for example, a rod 31 and an actuator 32.

[0043] For example, the rod 31 extends in the axial direction within the first flow passage 21a. One end of the rod 31 supports the catalyst C. The other end of the rod 31 is moved by an actuator 32, such as a motor, a cylinder, or a solenoid. The actuator 32 may be communicatively connected to the control device 90 by wire or wirelessly, and may be controlled by the control device 90. For example, the control device 90 adjusts the position of the catalyst C in the first flow passage 21a by controlling the actuator 32.

[0044] For example, a temperature sensor S1 may be attached to the burner 21. For example, the temperature sensor S1 may be disposed downstream of the catalyst C in the first flow path 21a. Also, for example, the temperature sensor S1 may be provided at the tip 21c. The temperature sensor S1 may be communicably connected to the control device 90 by wire or wirelessly, and may transmit measurement data to the control device 90. For example, the control device 90 may adjust the position of the catalyst C based on the temperature measured by the temperature sensor S1.

[0045] For example, when the temperature measured by the temperature sensor S1 exceeds a certain threshold, the control device 90 may move the catalyst C to a position away from the tip 21c. With such a configuration, excessive heating of the catalyst C can be avoided, and early deterioration of the catalyst C can be suppressed. Furthermore, the catalyst C is disposed at a position close to the tip 21c until the temperature measured by the temperature sensor S1 exceeds a certain threshold. Therefore, the catalyst C can be heated by the flame F.

[0046] The oxidant flow passage 22 supplies an oxidant (e.g., air) to the combustion space S. The oxidant flow passage 22 is in fluid communication with the combustion space S. For example, the oxidant flow passage 22 supplies the oxidant to the combustion space S from the radially outer side of the injection hole 21d. For example, the oxidant flow passage 22 is disposed radially outside the burner 21. For example, the oxidant flow passage 22 is continuous in the circumferential direction. In this embodiment, the oxidant flow passage 22 has a generally truncated cone shape. In this embodiment, the oxidant flow passage 22 is disposed concentrically with the burner 21.

[0047] For example, a valve V3 may be provided in an oxidant line L3 connected to the oxidant passage 22. The valve V3 may be communicably connected to the control device 90 via a wired or wireless connection, and may be controlled by the control device 90. For example, the control device 90 adjusts the flow rate of the oxidant supplied to the combustion space S via the oxidant passage 22 by controlling the opening degree of the valve V3.

[0048] The control device 90 controls all or part of the first combustor 10 and the second combustor 20. The control device 90 may also control at least some of the other components of the boiler 100. For example, the control device 90 may control the entire boiler 100. The boiler 100 may also include a main control device (not shown), and the control device 90 may communicate with the main control device. The control device 90 includes components such as a processor 90a, a storage device 90b, and a connector 90c, and these components are connected to each other via a bus. For example, the processor 90a includes a CPU (Central Processing Unit) and the like. For example, the storage device 90b includes a hard disk, a ROM in which programs and the like are stored, and a RAM as a work area and the like. The control device 90 is connected to each component of the boiler 100 via the connector 90c so as to be able to communicate with each other via wires or wirelessly. For example, the control device 90 may further include other components such as a display device such as a liquid crystal display or a touch panel, and an input device such as a keyboard, a button, or a touch panel. For example, the operation of the control device 90 may be realized by causing the processor 90a to execute a program stored in the storage device 90b.

[0049] Ammonia reacts on the catalyst C to cause the following reactions (1), (2), or a combination thereof: (1)NH3→1.5H2+0.5N2ΔH=45.4(kJ / mol) (2)2NH3+1.5O2→N2+3H2O ΔH=-382.6(kJ / mol)

[0050] For example, in this embodiment, the catalyst C in the second combustor 20 may cause both reactions (1) and (2). The controller 90 may control the second combustor 20 so that the ratio of reactions (1) and (2) is within an intended range. For example, the controller 90 may adjust the ratio of reactions (1) and (2) by controlling valves V1, V2, and V3 to control the amount of ammonia and oxidant supplied to the combustion space S.

[0051] Next, the combustion method according to this embodiment will be described.

[0052] 1, when starting up the furnace 1, the control device 90 first controls the first combustor 10 to inject a first fuel having a faster combustion speed than ammonia and an oxidizer from the first combustor 10 into the combustion space S. The mixed gas of the first fuel and the oxidizer is ignited by an ignition device (not shown) to form a flame F. The catalyst C in the second combustor 20 is heated by the flame F from the first combustor 10.

[0053] 5, when the temperature measured by the temperature sensor S1 exceeds a certain first threshold value, the control device 90 controls the valves V1, V2, and V3 to inject the second fuel containing ammonia and the oxidizer from the second combustor 20 into the combustion space S. The mixed gas of the second fuel and the oxidizer is ignited by an ignition device (not shown), and a flame F is formed. For example, the first threshold value may be a temperature at which the catalyst C starts to be activated.

[0054] When passing through the first flow passage 21a, a part of the ammonia is decomposed into hydrogen and nitrogen by the catalyst C. Hydrogen is more combustible than ammonia. Therefore, the combustibility of the mixed gas is improved. Also, when passing through the first flow passage 21a, another part of the ammonia is catalytically combusted in the catalyst C. Therefore, the temperature of the mixed gas is increased, and the combustibility of the mixed gas is further improved. As a result, the amount of unburned ammonia can be reduced.

[0055] When the temperature measured by the temperature sensor S1 exceeds a second threshold value, the control device 90 controls the actuator 32 to move the catalyst C away from the tip 21c, thereby preventing the catalyst C from being excessively heated.

[0056] As described above, the second combustor 20 according to the present embodiment includes the first flow path 21a for the second fuel containing ammonia, the tip 21c facing the combustion space S in the furnace 1, the burner 21 for injecting the second fuel into the furnace 1, and the catalyst C arranged upstream of the tip 21c in the first flow path 21a. According to this configuration, the catalyst C is heated by heat from the flame F in the furnace 1. Therefore, the catalyst C can be heated to a temperature at which the catalyst C starts to be activated without an additional device such as a heater. A part of the ammonia is decomposed into hydrogen and nitrogen by the catalyst C. Hydrogen is more combustible than ammonia. In addition, the other part of the ammonia is catalytically combusted in the catalyst C. Therefore, the temperature of the mixed gas is increased. As a result, the combustibility of the mixed gas is improved, and unburned ammonia can be reduced.

[0057] Moreover, in the second combustor 20 according to the present embodiment, the burner 21 includes an adjuster 30 that adjusts the position of the catalyst C in the first flow passage 21a. With this configuration, the temperature of the catalyst C is adjusted, and early deterioration of the catalyst C can be suppressed.

[0058] The combustion method according to the present embodiment includes burning a first fuel having a faster combustion speed than ammonia, which is injected from at least one first combustor 10, in the furnace 1, and burning a second fuel containing ammonia, which is injected from at least one second combustor 20, in the furnace 1. The second combustor 20 includes a first flow path 21a for the second fuel and a tip 21c facing the combustion space S in the furnace 1, a burner 21 for injecting the second fuel into the furnace 1, and a catalyst C arranged upstream of the tip 21c in the first flow path 21a. According to this configuration, the catalyst C in the second combustor 20 is heated by the flame F from the first combustor 10. Therefore, as described above, the catalyst C can be heated to a temperature at which the catalyst C starts to be activated without an additional device such as a heater. As a result, the combustibility of the mixed gas is improved, and unburned ammonia can be reduced.

[0059] Moreover, the combustion method according to the present embodiment includes adjusting the position of the catalyst C in the first flow passage 21a to adjust the temperature of the catalyst C. With this configuration, early deterioration of the catalyst C can be suppressed.

[0060] Moreover, the at least one first combustor 10 includes a plurality of first combustors 10, and the at least one second combustor 20 is surrounded by the plurality of first combustors 10. According to such a configuration, the catalyst C in the second combustor 20 is efficiently heated by the flame F from the plurality of first combustors 10 surrounding the second combustor 20.

[0061] Moreover, at least one first combustor 10 and at least one second combustor 20 are disposed to face each other in the furnace 1. According to such a configuration, the catalyst C in the second combustor 20 is efficiently heated by the flame F from the first combustor 10 facing the second combustor 20.

[0062] Next, other embodiments will be described.

[0063] 6 is a schematic cross-sectional view showing a combustor 40 according to the second embodiment. In this embodiment, the combustor is a radiant burner 40. The radiant burner 40 heats a surface 41d of a burner tile 41 by burning a mixed gas containing ammonia and an oxidizer (e.g., air), and heats an object (not shown) arranged at a position separated from the radiant burner 40 in a furnace (not shown) by radiant heat from the heated surface 41d. For example, a plurality of radiant burners 40 are arranged in a certain pattern along the wall surface of a furnace (not shown).

[0064] For example, the radiant burner 40 includes a burner tile 41 and a burner 42. The radiant burner 40 may further include other components.

[0065] The burner tile 41 is formed of a refractory material such as a molded product containing ceramic. In this embodiment, the burner tile 41 has a generally rectangular parallelepiped shape. The burner tile 41 is not limited to this shape and may have other shapes. The burner tile 41 includes a front surface 41a arranged to face the target object, and a back surface 41b opposite the front surface 41a.

[0066] In this embodiment, the burner tile 41 includes a recess 41c on the front surface 41a. The recess 41c is formed from the front surface 41a toward the back surface 41b. The recess 41c is used as a combustion space S. The recess 41c is defined by a surface 41d. That is, the surface 41d defines the combustion space S. In this embodiment, the surface 41d is a smooth spherical surface. In other embodiments, the surface 41d may have other shapes, such as, for example, a cylindrical shape or a polygonal prism shape. In other embodiments, the burner tile 41 may not include the recess 41c.

[0067] In this disclosure, the burner tile 41 including the recess 41c is also referred to as a "radiant cup." Also, in this disclosure, the radiant burner 40 including the radiant cup is also referred to as a "radiant cup burner."

[0068] The burner 42 protrudes from the burner tile 41 into the combustion space S. A tip (front end) 42b of the burner 42 faces the space inside the furnace. The burner 42 injects fuel containing ammonia into the combustion space S. In this embodiment, the burner 42 injects a mixed gas containing ammonia and an oxidizer (e.g., air) into the combustion space S (premixing type). The radiant burner 40 is not limited to the premixing type, and may be a diffusion type.

[0069] The burner 42 has a generally cylindrical or tubular shape. The burner 42 is located at the center of the front surface 41d. The burner 42 penetrates the wall of the burner tile 41 from the back surface 41b and protrudes into the recess 41c.

[0070] The burner 42 includes a plurality of injection holes 42a. The injection holes 42a inject the mixed gas into the combustion space S. The injection holes 42a are located between a tip 42b of the burner 42 and a bottom of the recess 41c in the axial direction. The number of the injection holes 42a may be two, three, four, five, or more. For example, the multiple injection holes 42a are evenly arranged along the circumferential direction.

[0071] In this embodiment, the injection holes 42a open in a generally radial direction. The injection holes 42a may have various shapes, such as a circular shape, an elliptical shape, or a polygonal shape.

[0072] The inner wall surface of the burner 42 defines a flow passage 42c for the mixed gas. The flow passage 42c is in fluid communication with the injection hole 42a. The flow passage 42c has a generally cylindrical shape.

[0073] A valve V5 may be provided in an ammonia line L5 connected to the burner 42. The valve V5 may be communicably connected to the control device 90 via wire or wirelessly, and may be controlled by the control device 90. For example, the control device 90 adjusts the flow rate of ammonia supplied to the burner 42 by controlling the opening degree of the valve V5.

[0074] A valve V6 may be provided in an oxidizer line L6 connected to the burner 42. The valve V6 may be communicatively connected to the control device 90 via wire or wirelessly, and may be controlled by the control device 90. For example, the control device 90 adjusts the flow rate of the oxidizer supplied to the burner 42 by controlling the opening degree of the valve V6.

[0075] As in the first embodiment, the controller 90 may control the valves V5 and V6 to control the amounts of ammonia and oxidant supplied to the combustion space S, thereby adjusting the ratios of the above reactions (1) and (2).

[0076] A catalyst C is disposed in the flow passage 42c. The catalyst C is disposed upstream of the tip 42b in the flow of ammonia. For example, the catalyst C may be the same as that used in the second combustor 20 of the first embodiment.

[0077] The radiant burner 40 includes an adjuster 30 that adjusts the position of the catalyst C in the flow passage 42c. For example, the adjuster 30 includes a rod 31 and an actuator 32. For example, the adjuster 30 may be similar to that used in the second combustor 20 of the first embodiment.

[0078] For example, a temperature sensor S2 is attached to the burner 42. For example, the temperature sensor S2 may be disposed downstream of the catalyst C in the flow path 42c. Also, for example, the temperature sensor S2 may be provided on the rear surface of the tip 42b. The temperature sensor S2 may be connected to the control device 90 so as to be able to communicate with the control device 90 by wire or wirelessly, and may transmit measurement data to the control device 90. For example, the control device 90 may adjust the position of the catalyst C based on the temperature measured by the temperature sensor S2.

[0079] For example, when the temperature measured by the temperature sensor S2 exceeds a certain threshold, the control device 90 may move the catalyst C to a position away from the tip 42b. This configuration can suppress early deterioration of the catalyst C. Furthermore, the catalyst C is positioned close to the tip 42b until the temperature measured by the temperature sensor S2 exceeds a certain threshold. Therefore, the catalyst C can be heated by the flame.

[0080] The burner 42 includes a heat sink H disposed at the tip 42b. The heat sink H faces the space within the furnace. For example, the heat sink H includes structures that increase the surface area, such as fins, needles, or bellows. For example, the heat sink H may be integrally formed with the tip 42b or may be coupled to the tip 42b.

[0081] The wall (case) of the burner 42 including the tip 42b is formed of a metal such as SUS310S, Alloy 600, etc. The tip 42b separates the flow passage 42c from the combustion space S. Therefore, the tip 42b can protect the catalyst C in the flow passage 42c from the environment in the furnace.

[0082] Next, the operation of the radiant burner 40 will be described.

[0083] A mixed gas containing ammonia and an oxidizer is injected from the injection hole 42a of the burner 42 toward the combustion space S. The mixed gas is injected from the injection hole 42a generally radially outward. The mixed gas forms a flow along the surface 41d of the recess 41c. The pressure in the central region of the combustion space S, more specifically, the pressure around the tip 42b, is lower than the pressure in the surrounding region. Therefore, the mixed gas changes its flow direction from the radially outer side to the radially inner side, and further flows toward the tip 42b along the central axis. The mixed gas ignites starting from the tip 42b, and is sufficiently heated and combusted before changing the flow direction. The high-temperature combustion gas flows toward the tip 42b.

[0084] The catalyst C is heated by heat from the flame in the combustion space S to a temperature at which it starts to become activated. When passing through the flow path 42c, a part of the ammonia is decomposed into hydrogen and nitrogen by the catalyst C. Hydrogen is more combustible than ammonia. Therefore, the combustibility of the mixed gas is improved. Also, when passing through the flow path 42c, another part of the ammonia is catalytically combusted in the catalyst C. Therefore, the temperature of the mixed gas is increased, and the combustibility of the mixed gas is further improved. As a result, the amount of unburned ammonia can be reduced.

[0085] When the temperature measured by the temperature sensor S2 exceeds a certain threshold, the control device 90 controls the actuator 32 to move the catalyst C away from the tip 42b, thereby preventing the catalyst C from being overheated.

[0086] The radiant burner 40 according to the present embodiment as described above has substantially the same effects as the second combustor 20 according to the first embodiment. In the present embodiment, the combustor is a radiant cup burner equipped with a burner tile 41 that holds a burner 42. In the present embodiment as well, it is possible to reduce unburned ammonia.

[0087] In the radiant burner 40 according to the present embodiment, the burner 42 includes a heat sink H disposed at the tip 42b and facing the space inside the furnace. With this configuration, the tip 42b can be heated quickly, and therefore the catalyst C can be heated quickly.

[0088] Moreover, in the radiant burner 40 according to this embodiment, the tip 42b is formed of metal and protects the catalyst C from the environment inside the furnace. With this configuration, early deterioration of the catalyst C can be suppressed.

[0089] 7 is a schematic cross-sectional view showing a combustor 40A according to the third embodiment. In this embodiment, the combustor is a radiant burner 40A. The radiant burner 40A differs from the radiant burner 40 according to the second embodiment in the configuration of the burner 42. The other configurations of the radiant burner 40A may be the same as those of the radiant burner 40.

[0090] In this embodiment, the burner 42 does not include a regulator and a heat sink. In this embodiment, the wall (case) of the burner 42 is divided into a main body 42d and a holder 42e. Other configurations of the burner 42 may be the same as those of the radiant burner 40 according to the second embodiment.

[0091] For example, the main body 42d and the holder 42e are separated from each other at a position spaced upstream from the tip 42b. The main body 42d forms a portion of the upstream flow passage 42c.

[0092] The holder 42e is removably attached to the main body 42d. For example, the holder 42e may be fitted to the main body 42d. Also, for example, a male thread may be formed on one of the holder 42e and the main body 42d, and a female thread that engages with the male thread may be formed on the other. The method of attaching the holder 42e to the main body 42d is not limited to the above. The holder 42e holds the catalyst C. In this embodiment, the holder 42e forms a part of the downstream flow path 42c. In this embodiment, the holder 42e includes a tip 42b.

[0093] When the catalyst C deteriorates, the holder 42e and the catalyst C are removed from the main body 42d. For example, the catalyst C may be replaced with a new catalyst, and the holder 42e may be reattached to the main body 42d. Alternatively, both the catalyst C and the holder 42e may be replaced with new ones.

[0094] The radiant burner 40A according to the present embodiment as described above has substantially the same effects as the second combustor 20 according to the first embodiment and the radiant burner 40 according to the second embodiment. In the present embodiment, the burner 42 includes a main body 42d that forms a flow path 42c, and a holder 42e that is removable from the main body 42d and holds the catalyst C. With this configuration, the deteriorated catalyst C can be replaced with a new catalyst.

[0095] This disclosure also includes a method for modifying a combustor. If the burner nozzle is fixed with a flange or the like, this modification method is performed by removing the nozzle and installing a catalyst inside the nozzle. If the nozzle cannot be removed, the tip of the burner is cut and the catalyst is installed from the cut surface.

[0096] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above embodiments. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. In addition, the steps of the method of the above embodiments do not have to be performed in the above order, and may be performed in a different order as long as there is no technical contradiction.

[0097] The disclosure can promote the use of ammonia leading to reduced CO2 emissions, thereby contributing, for example, to Sustainable Development Goals (SDGs) Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13 "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0098] 1 furnace 10 First Combustor 20 Second Combustor (Combustor) 21 Burner 21a First flow path (flow path) 21c Tip 30 regulator 40 Radiant burner (combustor, radiant cup burner) 40A Radiant burner (combustor, radiant cup burner) 41 Burner Tile 42 Burner 42b Tip 42c Flow path 42d Main unit 42e Holder C catalyst H Heatsink S Combustion space

Claims

1. a burner including a flow path for a fuel including ammonia and a tip facing a space in the furnace, the burner injecting the fuel into the furnace; a catalyst disposed in the flow path upstream of the tip; A combustor comprising:

2. The combustor of claim 1 , wherein the burner includes an adjuster for adjusting a position of the catalyst in the flow passage.

3. The combustor of claim 1 , wherein the burner includes a heat sink disposed at the tip and facing the space within the furnace.

4. The burner is A main body forming the flow path; A holder that is removable from the main body and holds the catalyst; Including, The combustor of claim 1 .

5. The combustor of claim 1 , wherein the tip is formed of metal to protect the catalyst from the environment within the furnace.

6. The combustor is a radiant cup burner having a burner tile that holds the burner. The combustor of claim 1 .

7. burning a first fuel in a furnace, the first fuel having a burning velocity faster than ammonia, the first fuel being injected from at least one first combustor; A second fuel including ammonia is combusted in the furnace, the second fuel being injected from at least one second combustor, The at least one second combustor comprises: a burner including a flow path for the second fuel and an end facing the space in the furnace, the burner injecting the second fuel into the furnace; a catalyst disposed in the flow path upstream of the tip; Equipped with And, Included are combustion methods.

8. adjusting a temperature of the catalyst by adjusting a position of the catalyst in the flow path; The method of claim 7, comprising:

9. The method of claim 7 , wherein the burner of the second combustor includes a heat sink disposed at the tip and exposed within the furnace.

10. the at least one first combustor comprises a plurality of first combustors; the at least one second combustor is surrounded by the plurality of first combustors. The combustion method according to claim 7.

11. the at least one first combustor and the at least one second combustor are disposed opposite each other within the furnace. The combustion method according to claim 7.

12. The burner of the second combustor is A main body forming the flow path; A holder that is removable from the main body and holds the catalyst; Including, The combustion method according to claim 7.

13. 8. The method of claim 7, wherein the tip of the burner of the second combustor is formed of metal to protect the catalyst from the environment within the furnace.

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