Burner and combustor

Abstract

To provide a burner capable of suppressing back-fire with a simple configuration.SOLUTION: A burner 3 includes a cylindrical body 4 forming a flow passage 40 in which an air-fuel mixture of main combustion air and gas fuel flows. The cylindrical body 4 includes a contraction part 41 of which diameter is contracted toward the downstream side and in which a flow passage area is minimized. The burner 3 may further include a fuel injector 8 that is disposed in the cylindrical body 4 and injects the gas fuel into the main combustion air. In this case, the contraction part 41 may be located on the downstream side of the fuel injector 8.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a burner for generating a flame, and to a combustor including said burner. [Background technology]

[0002] Conventionally, a burner that injects a mixture of gas fuel and air to generate a flame has been known. For example, Patent Document 1 discloses a combustor including a plurality of burners for use in a gas turbine.

[0003] Specifically, in Patent Document 1, each burner includes a mixing passage and four fuel nozzles arranged around the mixing passage. The mixing passage is configured as a straight hole, and the fuel nozzles inject gaseous fuel near the upstream end of the mixing passage into the air that flows into the mixing passage. The gaseous fuel and air mixture is ignited downstream of the burner, thereby generating a flame. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-173191 Summary of the Invention [Problem to be solved by the invention]

[0005] The burner in Patent Document 1 uses premixed combustion, and therefore emits little NOx. In addition, the burner in Patent Document 1 employs a structure for preventing flashback from the outlet of the mixing passage. In response to this, it is desired to suppress flashback with an even simpler structure.

[0006] In view of the above, an object of the present disclosure is to provide a burner capable of suppressing flashback with a simple configuration, and a combustor including the burner. [Means for solving the problem]

[0007] From one aspect, the present disclosure provides a burner comprising a cylinder that forms a flow path through which a mixture of main combustion air and gas fuel flows, the cylinder having a diameter that narrows toward the downstream side and a reduced section where the flow path area is minimized.

[0008] From another aspect, the present disclosure provides a combustor including a plurality of the above-mentioned burners. Effect of the Invention

[0009] According to the present disclosure, there is provided a burner capable of suppressing flashback with a simple configuration, and a combustor including the burner. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a combustor including a burner according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing the burner, partially in section; [Diagram 3] FIG. 2 is a perspective view of an intermediate portion of the burner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Fig. 2 shows a burner 3 according to one embodiment, and Fig. 1 shows a combustor 1 including a plurality of burners 3. For example, the combustor 1 is used in a gas turbine, a boiler, or the like.

[0012] The combustor 1 includes an external cylinder 11, an inner cylinder 12 housed in the external cylinder 11, and an end plate 13 that closes one of the openings of the external cylinder 11 and the inner cylinder 12. For ease of explanation, the side of the end plate 13 in the axial direction of the external cylinder 11 and the inner cylinder 12 will be referred to as the front, and the opposite side will be referred to as the rear.

[0013] A cylindrical flow passage that opens toward the rear is formed between the inner cylinder 12 and the outer cylinder 11. Air is supplied to this cylindrical flow passage from the rear. For example, the air supplied to the cylindrical flow passage is compressed air.

[0014] A partition wall 14 is provided in the inner cylinder 12 to separate the space in the inner cylinder 12 into an air chamber 15 at the front and a combustion chamber 16 at the rear. Furthermore, a straightening plate 18 is provided in the air chamber 15 to separate the air chamber 15 into a pre-straightening space 15a and a post-straightening space 15b. A plurality of openings are provided in the portion of the inner cylinder 12 facing the pre-straightening space 15a, and air flows from the cylindrical flow path into the pre-straightening space 15a through these openings. A plurality of through holes are provided in the straightening plate 18, and the straightening plate 18 straightens the air that flows into the pre-straightening space 15a into a uniform flow along the axial direction of the inner cylinder 12. Therefore, a uniform flow of air flows into the post-straightening space 15b along the axial direction of the inner cylinder 12.

[0015] A plurality of burners 3 are arranged in the post-straightening space 15b. That is, the pre-straightening space 15a is in front of the burners 3. The burners 3 are for generating a flame in the combustion chamber 16. For example, the burners 3 are arranged at equal angular intervals on at least one circumference centered on the center line of the inner cylinder 12. Each burner 3 extends in the front-rear direction, and the rear end of each burner 3 penetrates the partition wall 14. In the illustrated example, the rear end surface of each burner 3 is located rearward of the rear surface of the partition wall 14, but the rear end surface of each burner 3 may be flush with the rear surface of the partition wall 14. Alternatively, each burner 3 does not necessarily need to penetrate the partition wall 14, and the rear end surface of each burner 3 may be joined to the front surface of the partition wall 14.

[0016] Each burner 3 forms a mixture of main combustion air and gas fuel inside, and injects the mixture into the combustion chamber 16. A part of the air that has flowed into the post-straightening space 15b flows into each burner 3 as main combustion air. The gas fuel is, for example, natural gas or hydrogen.

[0017] In this embodiment, a part of the air that flows into the post-straightening space 15b also flows into each burner 3 as pilot combustion air and protective air. The pilot combustion air and protective air will be described later.

[0018] All the burners 3 are supplied with gas fuel through a gas fuel supply passage 21 and with pilot fuel through a pilot fuel supply passage 22. The pilot fuel may be the same as the gas fuel or may be different.

[0019] The combustor 1 includes an ignition device 17 that ignites the air-fuel mixture injected from each burner 3 in the combustion chamber 16. The ignition device 17 penetrates the inner cylinder 12 and the outer cylinder 11. A flame is generated in the combustion chamber 16 by igniting the air-fuel mixture by the ignition device 17. In this embodiment, a flame is also generated in each burner 3 by transmitting the flame to the burner 3. Note that a plurality of ignition devices 17 may be provided so as to be scattered in the circumferential direction.

[0020] Next, the structure of each burner 3 will be described in detail with reference to FIG. 2. The burner 3 includes a first cylindrical body 4, a second cylindrical body 5, and a third cylindrical body 6, which are arranged coaxially. The axial direction of the first cylindrical body 4, the second cylindrical body 5, and the third cylindrical body 6 is the front-rear direction. The second cylindrical body 5 is arranged outside the first cylindrical body 4, and the third cylindrical body 6 is arranged outside the second cylindrical body 5, and the first cylindrical body 4, the second cylindrical body 5, and the third cylindrical body 6 are partially overlapped. The burner 3 also includes a cylindrical fuel injector 8 arranged inside the first cylindrical body 4, and a lance 7 arranged at the center of the first cylindrical body 4.

[0021] The fuel injector 8 injects gas fuel into the main combustion air within the front end of the first cylindrical body 4. The first cylindrical body 4 forms a mixture flow passage 40 between the lance 7 and the main combustion air, through which a mixture of the main combustion air and the gas fuel flows.

[0022] More specifically, the lance 7 extends from a position forward of the first cylindrical body 4 to a position approximately 2 / 3 the length of the first cylindrical body 4, and tapers toward the rear. Note that the length of the lance 7 is not limited to the above and can be changed as appropriate.

[0023] The fuel injector 8 is penetrated by the lance 7. In this embodiment, the fuel injector 8 protrudes forward from the first cylindrical body 4. The fuel injector 8 extends in the front-rear direction so as to overlap with a front portion of the lance 7, and a rear portion of the fuel injector 8 overlaps with the front end portion of the first cylindrical body 4 when viewed from the radial direction of the first cylindrical body 4.

[0024] Between the lance 7 and the fuel injector 8, an inner air flow passage is formed through which the main combustion air, which is a portion of the air that flows into the post-straightening space 15b, flows, and between the fuel injector 8 and the front end of the first cylindrical body 4, an outer air flow passage is formed through which the main combustion air, which is a portion of the air that flows into the post-straightening space 15b, flows.

[0025] The fuel injector 8 has a plurality of inner injection holes 81 that open radially inward and a plurality of outer injection holes 82 that open radially outward. For example, the inner injection holes 81 are arranged at equal angular intervals in the circumferential direction, and the outer injection holes 82 are arranged at equal angular intervals in the circumferential direction. Injection of gas fuel from the inner injection holes 81 forms a mixture of main combustion air and gas fuel flowing through the inner air flow passage, and injection of gas fuel from the outer injection holes 82 forms a mixture of main combustion air and gas fuel flowing through the outer air flow passage.

[0026] The opening direction of each inner injection hole 81 may be parallel to a direction perpendicular to the axial direction of the fuel injector 8, or may be inclined forward or backward with respect to the direction perpendicular to the axial direction of the fuel injector 8. Similarly, the opening direction of each outer injection hole 82 may be parallel to a direction perpendicular to the axial direction of the fuel injector 8, or may be inclined forward or backward with respect to the direction perpendicular to the axial direction of the fuel injector 8.

[0027] An annular buffer chamber 83 communicating with the inner injection hole 81 and the outer injection hole 82 is formed inside the fuel injector 8, and a plurality of inlet passages 84 are formed to introduce the gas fuel supplied from the gas fuel supply passage 21 into the buffer chamber 83. Note that the inlet passages 84 may be omitted and the gas fuel may be directly supplied from the gas fuel supply passage 21 to the buffer chamber 83.

[0028] An annular inner baffle plate 9A is arranged between the lance 7 and the fuel injector 8 in the radial direction of the first cylindrical body 4, and an annular outer baffle plate 9B is arranged between the fuel injector 8 and the front end of the first cylindrical body 4 in the radial direction of the first cylindrical body 4.

[0029] The inner flow straightening plate 9A has a plurality of inner guide grooves 91 that open radially outward and whose openings are closed by the inner circumferential surface of the fuel injector 8. The number of inner guide grooves 91 is the same as the number of inner injection holes 81 of the fuel injector 8, and each inner injection hole 81 is located at the center of the corresponding inner guide groove 91 when viewed from the front-rear direction.

[0030] In this embodiment, the inner straightening plate 9A is located forward of the inner injection hole 81. Therefore, the inner guide groove 91 plays a role in allowing the main combustion air flowing through the inner air passage to flow along the inner side surface of the fuel injector 8 so as to cross the inner injection hole 81. In other words, the inner straightening plate 9A straightens the main combustion air to a flow in the axial direction of the first cylindrical body 4. However, the inner straightening plate 9A may be located rearward of the inner injection hole 81 and straighten the air-fuel mixture formed by the injection of gas fuel from the inner injection hole 81 to a flow in the axial direction of the first cylindrical body 4.

[0031] Similarly, the outer flow straightening plate 9B has a plurality of outer guide grooves 92 that open radially inward and whose openings are closed by the outer peripheral surface of the fuel injector 8. The number of outer guide grooves 92 is the same as the number of outer injection holes 82 of the fuel injector 8, and each outer injection hole 82 is located at the center of the corresponding outer guide groove 92 when viewed from the front-to-rear direction.

[0032] In this embodiment, the outer flow straightening plate 9B is located forward of the outer injection hole 82. Therefore, the outer guide groove 92 plays a role in allowing the main combustion air flowing through the outer air flow passage to flow along the outer surface of the fuel injector 8 so as to cross the outer injection hole 82. In other words, the outer flow straightening plate 9B straightens the main combustion air into a flow in the axial direction of the first cylindrical body 4. However, the outer flow straightening plate 9B may be located rearward of the outer injection hole 82 and straighten the air-fuel mixture formed by the injection of gas fuel from the outer injection hole 82 into a flow in the axial direction of the first cylindrical body 4.

[0033] The first cylindrical body 4 has a reduced diameter toward the downstream side, in other words, toward the rear, and has a reduced section 41 downstream of the lance 7 where the flow area of ​​the mixture flow passage 40 is minimum. In other words, the reduced section 41 is located downstream of the fuel injector 8. The reduced section 41 is also the part where the diameter of the first cylindrical body 4 is minimum.

[0034] For example, when the flow area of ​​the mixture flow passage 40 at a position adjacent to the fuel injector 8 is D1 and the flow area of ​​the mixture flow passage 40 at the contraction portion 41 is D2, D2 is 0.2 to 0.8 times D1. When the diameter of the lance 7 at the position adjacent to the fuel injector 8 is Di and the inner diameter of the first cylindrical body 4 is Do, D1=π×(Do / 2−Di / 2) 2 The flow velocity of the air-fuel mixture in the contracting portion 41 is, for example, not less than 20 m / s and not more than 60 m / s.

[0035] The second cylindrical body 5 extends from approximately the center of the first cylindrical body 4 to a position slightly rearward of the first cylindrical body 4, and the diameter of the second cylindrical body 5 decreases toward the rear. The second cylindrical body 5 has a pilot burner 51 that injects pilot fuel downstream of the first cylindrical body 4. The pilot burner 51 is composed of a plurality of injection holes arranged at equal angular intervals in the circumferential direction. In this embodiment, the pilot burner 51 injects pilot fuel radially inward. However, the pilot burner 51 may also inject pilot fuel in the axial direction of the first cylindrical body 4.

[0036] The second cylindrical body 5 is formed with a cylindrical internal flow passage 52 that communicates with a plurality of injection holes that constitute the pilot burner 51. Pilot fuel supplied from a pilot fuel supply passage 22 is introduced into this internal flow passage 52 through an introduction passage 33, which will be described later.

[0037] A cylindrical flow passage 50 is formed between the first cylindrical body 4 and the second cylindrical body 5. As shown in Fig. 3, the front end of the second cylindrical body 5 is supported by a plurality of supports 31 attached to the outer circumferential surface of the first cylindrical body 4. The supports 31 are scattered in the circumferential direction, and the cylindrical flow passage 50 opens into the post-straightening space 15b through the spaces between the supports 31. Therefore, a portion of the air that flows into the post-straightening space 15b flows into the cylindrical flow passage 50 as pilot combustion air.

[0038] Pilot combustion air is supplied to a pilot burner 51 through a cylindrical flow passage 50. A mixture of pilot fuel and pilot combustion air is formed by the injection of pilot fuel from the pilot burner 51. The flame generated by the combustion of this mixture plays a role in stabilizing the flame generated by the combustion of a mixture of main combustion air and gas fuel.

[0039] The third cylindrical body 6 extends from a position slightly behind the front end of the second cylindrical body 5 to a position away from the second cylindrical body 5. The third cylindrical body 6 has a narrower diameter toward the downstream side in the region where it overlaps with the second cylindrical body 5, but has a wider diameter toward the downstream side in a region further to the rear. The third cylindrical body 6 surrounds the combustion zone 30 downstream of the second cylindrical body 5.

[0040] A cylindrical flow passage 60 is formed between the third cylindrical body 6 and the second cylindrical body 5. A part of the air that has flowed into the post straightening space 15b passes through the third cylindrical body 6 and flows into the cylindrical flow passage 60 as protective air that protects the third cylindrical body 6. The protective air is supplied to the combustion zone 30 through the cylindrical flow passage 60 so as to flow along the inner circumferential surface of the third cylindrical body 6.

[0041] The front end of the third cylindrical body 6 is attached to the second cylindrical body 5 via a ring 32. The ring 32 closes the above-mentioned cylindrical flow path 60 from the front. In this embodiment, the ring 32 is provided integrally with the third cylindrical body 6. However, the ring 32 may be a separate body from the third cylindrical body 6.

[0042] In this embodiment, a plurality of introduction passages 33 are formed so as to penetrate the ring 32 and the second cylindrical body 5 in portions located outside the internal flow passage 52. As described above, pilot fuel is supplied from the pilot fuel supply passage 22 to the internal flow passage 52 through the introduction passages 33. For example, the introduction passages 33 are arranged at equal angular intervals in the circumferential direction.

[0043] The third cylinder 6 includes an inner wall 61 facing the above-mentioned cylindrical flow passage 60 and the combustion zone 30, an outer wall 62 forming an internal flow passage 64 between itself and the inner wall 61, and a rear end portion 63 closing the internal flow passage 64 from the rear. The front ends of the inner wall 61 and the outer wall 62 are joined to the ring 32.

[0044] A plurality of through holes 65 are provided in a portion of the outer wall 62 located outside the combustion zone 30. For example, the through holes 65 are arranged in a plurality of rows arranged in the front-rear direction, and are arranged at equal angular intervals in the circumferential direction. On the other hand, a plurality of through holes 66 are provided in the front end portion of the inner wall 61. For example, the through holes 66 are arranged at equal angular intervals in the circumferential direction. For this reason, a part of the air that has flowed into the post straightening space 15b flows into the internal flow passage 64 through the through holes 65 as protective air, flows through the internal flow passage 64 from rear to front, and then flows into the cylindrical flow passage 60 through the through holes 66. The protective air is then supplied to the combustion zone 30 through the cylindrical flow passage 60 as described above.

[0045] As described above, the burner 3 of this embodiment uses premixed combustion, resulting in low NOx emissions. In addition, since the flow velocity of the mixture is maximized in the contraction section 41 of the first cylindrical body 4, backfire upstream of the contraction section 41 can be suppressed with the simple configuration in which the first cylindrical body 4 has the contraction section 41.

[0046] Moreover, in this embodiment, since the reduction portion 41 is located downstream of the fuel injector 8, backfire up to the fuel injector 8 is suppressed. Therefore, burnout of the fuel injector 8 can be suppressed.

[0047] In addition, in this embodiment, the inner and outer straightening plates 9A and 9B straighten the main combustion air in the axial direction of the first cylindrical body 4, so that the flow of the mixture in the contraction section 41 becomes uniform. Furthermore, since the inner straightening plate 9A has an inner guide groove 91 and the outer straightening plate 9B has an outer guide groove 92, when a backfire occurs upstream of the contraction section 41, MMX (Micro-mix) combustion occurs near the inner injection hole 81 and the outer injection hole 82. MMX combustion is a diffusion combustion with almost no premixing, in which a small flame is formed and the gas fuel is burned immediately after being injected. Therefore, it is possible to prevent the inner straightening plate 9A, the fuel injector 8, the outer straightening plate 9B, and the first cylindrical body 4 from being burned.

[0048] In the combustion zone 30 in the third cylindrical body 6, the mixture is burned to generate a flame. In the absence of the third cylindrical body 6, a circulating vortex is formed around the flame downstream of the second cylindrical body 5, which makes it easy for flashback to occur in the second cylindrical body 5. In contrast, if the combustion zone 30 downstream of the second cylindrical body 5 is surrounded by the third cylindrical body 6 as in this embodiment, such a circulating vortex is unlikely to form in the third cylindrical body 6, so that flashback to the second cylindrical body 5 can be suppressed. Moreover, protective air is supplied through the cylindrical flow path 60 between the second cylindrical body 5 and the third cylindrical body 6 so as to cover the flame, so that the effect of suppressing flashback can be enhanced. Furthermore, the protective air flows along the inner circumferential surface of the third cylindrical body 6, so that the flame is also suppressed from contacting the third cylindrical body 6.

[0049] In addition, since the protective air flows through the internal flow passage 64 between the inner wall 61 and the outer wall 62 of the third cylindrical body 6 and then flows into the cylindrical flow passage 60, the third cylindrical body 6 can be cooled by the protective air.

[0050] Incidentally, the present disclosure is particularly useful when the gas fuel is hydrogen, since hydrogen has a high burning rate and is prone to flashback.

[0051] <Modification> The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0052] For example, instead of the fuel injector 8 that injects gas fuel into the front end of the first cylindrical body 4, a fuel injector that injects gas fuel into the pre-straightening space 15a may be used. In this case, the air-fuel mixture formed in the pre-straightening space 15a flows into the first cylindrical body 4. In addition, when a fuel injector that injects gas fuel into the pre-straightening space 15a is used, nothing needs to be placed inside the first cylindrical body 4. However, if a straightening plate that straightens the air-fuel mixture into a flow in the axial direction of the first cylindrical body 4 is placed inside the first cylindrical body 4, the flow of the air-fuel mixture in the contracting section 41 will be uniform.

[0053] Furthermore, regardless of whether a fuel injector 8 that injects gas fuel within the front end of the first cylindrical body 4 is used, or a fuel injector that injects gas fuel within the pre-straightening space 15a is used, the second cylindrical body 5 and the third cylindrical body 6 may be omitted.

[0054] In addition, in the combustor 1, a pilot burner may be disposed in the center of the first cylindrical body 4 so as to be surrounded by the burner 3, and a mixture of pilot fuel and pilot combustion air may be injected from the pilot burner into the combustion chamber 16.

[0055] <Summary> In a first aspect, the present disclosure provides a burner comprising, from one side, a cylinder forming a flow passage through which a mixture of main combustion air and gaseous fuel flows, the cylinder having a diameter that narrows toward the downstream side and a reduced section where the flow passage area is minimized.

[0056] According to the above configuration, since premixed combustion is used, NOx emissions are low. In addition, since the flow velocity of the mixture is maximized in the contraction section, flashback to the upstream side of the contraction section can be suppressed with a simple configuration in which the cylinder has a contraction section.

[0057] As a second aspect, the burner of the first aspect may further include a fuel injector disposed in the cylinder for injecting the gas fuel into the main combustion air, and the contraction portion may be located downstream of the fuel injector. With this configuration, backfire up to the fuel injector is suppressed, thereby suppressing burnout of the fuel injector.

[0058] As a third aspect, in the first aspect, for example, the burner may further include a fuel injector that injects the gas fuel into a space in front of the cylindrical body.

[0059] As a fourth aspect, the burner according to the second aspect may further include a straightening plate disposed between the fuel injector and the cylinder in the radial direction of the cylinder for straightening the main combustion air or the mixture in the axial direction of the cylinder. With this configuration, the flow of the mixture in the contracting section becomes uniform.

[0060] As a fifth aspect, the burner according to the third aspect may further include a flow straightening plate disposed within the cylindrical body for straightening the air-fuel mixture in the axial direction of the cylindrical body. With this configuration, the flow of the air-fuel mixture in the contracting section becomes uniform.

[0061] As a sixth aspect, in the fourth aspect, the fuel injector is cylindrical and has a plurality of inner injection holes opening radially inward and a plurality of outer injection holes opening radially outward, the baffle is an annular outer baffle and has a plurality of outer guide grooves that allow the main combustion air to flow along the outer surface of the fuel injector so as to cross the plurality of outer injection holes, and the burner may further include a lance disposed at the center of the cylindrical body, and an annular inner baffle having a plurality of inner guide grooves that allow the main combustion air to flow along the inner surface of the fuel injector so as to cross the plurality of inner injection holes, disposed between the lance and the fuel injector in the radial direction of the cylindrical body. According to this configuration, when a flashback occurs upstream of the reduction section, MMX (Micro-mix) combustion occurs near the inner injection hole and the outer injection hole, so that it is possible to avoid burning of the inner baffle, the fuel injector, the outer baffle, and the cylindrical body.

[0062] As a seventh aspect, in any one of the first to fifth aspects, the cylinder is a first cylinder, and the burner is a second cylinder arranged outside the first cylinder, the second cylinder having a pilot burner for injecting pilot fuel downstream of the first cylinder, and a third cylinder arranged outside the second cylinder, expanding toward the downstream side, and surrounding the combustion zone downstream of the second cylinder, and pilot combustion air may be supplied to the pilot burner through between the first cylinder and the second cylinder, and protective air for protecting the third cylinder may be supplied to the combustion zone through between the second cylinder and the third cylinder so as to flow along the third cylinder. In the combustion zone in the third cylinder, the mixture is burned to generate a flame. If there is no third cylinder, a circulating vortex is formed around the flame downstream of the second cylinder, which makes it easy for backfire to occur in the second cylinder. In contrast, if the combustion zone downstream of the second cylinder is surrounded by the third cylinder as in the above configuration, such a circulating vortex is unlikely to form inside the third cylinder, so flashback into the second cylinder can be suppressed. Moreover, protective air is supplied between the second and third cylinders to cover the flame, which enhances the flashback suppression effect. Furthermore, the protective air flows along the third cylinder, which also suppresses the flame from coming into contact with the third cylinder.

[0063] As an eighth aspect, in the seventh aspect, the third cylinder may have an inner wall and an outer wall, and a part of the protective air may flow between the inner wall and the outer wall and then pass between the second cylinder and the third cylinder to be supplied to the combustion zone. With this configuration, the third cylinder can be cooled by the protective air flowing between the inner wall and the outer wall.

[0064] As a ninth aspect, in any one of the first to eighth aspects, the gas fuel may be hydrogen. This configuration is particularly useful when the gas fuel is hydrogen, since hydrogen has a high burning speed and is prone to flashback.

[0065] In a tenth aspect, the present disclosure provides, from another aspect, a combustor including a plurality of burners according to any one of the first to ninth aspects. [Explanation of symbols]

[0066] 1 Combustor 3 Burner 30 Combustion Zone 4 First cylinder 40 Mixture flow path 41 Reduced part 5 Second cylinder 50 Cylindrical channel 51 Pilot Burner 6 Third cylinder 60 Cylindrical channel 61 Inner wall 62 Exterior Wall 7. Lance 8 fuel injector 81 Inner injection hole 82 Outer injection hole 9A inner rectifier plate 9B Outer rectifier plate 91 Inner guide groove 92 Outer guide groove

Claims

1. A cylindrical body that forms a passage through which a mixture of main combustion air and gaseous fuel flows, The device comprises a fuel injector disposed within the cylindrical body for injecting the gaseous fuel into the main combustion air, The cylindrical body has a narrowing section that decreases in diameter towards the downstream side, resulting in the smallest flow area. The reduced portion is located downstream of the fuel injector, and is a burner.

2. A cylindrical body that forms a flow path through which a mixture of main combustion air and gaseous fuel flows, A fuel injector that injects the gaseous fuel in a space located in front of the cylindrical body, The cylindrical body is equipped with a flow straightening plate that directs the mixture to flow in the axial direction of the cylindrical body, The aforementioned cylindrical body is a burner having a reduced diameter towards the downstream side, with a narrowed section that minimizes the flow path area.

3. The burner according to claim 1, further comprising a flow straightening plate positioned between the fuel injector and the cylindrical body in the radial direction of the cylindrical body, for straightening the main combustion air or the mixture to flow in the axial direction of the cylindrical body.

4. The fuel injector is cylindrical and has a plurality of inner injection holes that open radially inward and a plurality of outer injection holes that open radially outward. The rectifier plate is an annular outer rectifier plate and has a plurality of outer guide grooves that allow the main combustion air to flow along the outer surface of the fuel injector so as to traverse the plurality of outer injection holes. A lance positioned at the center of the cylindrical body, An annular inner rectifier plate is positioned between the lance and the fuel injector in the radial direction of the cylindrical body, having a plurality of inner guide grooves that allow the main combustion air to flow along the inner surface of the fuel injector so as to traverse the plurality of inner injection holes, The burner according to claim 3, further comprising:

5. The aforementioned cylindrical body is the first cylindrical body, A second cylinder is positioned outside the first cylinder, and the second cylinder has a pilot burner for injecting pilot fuel downstream of the first cylinder, The invention further comprises a third cylindrical body positioned outside the second cylindrical body, which expands in diameter toward the downstream side and surrounds the combustion zone downstream of the second cylindrical body, Air for pilot combustion is supplied to the pilot burner through the space between the first cylinder and the second cylinder. The burner according to any one of claims 1 to 4, wherein protective air protecting the third cylinder is supplied to the combustion zone through the space between the second cylinder and the third cylinder so as to flow along the third cylinder.

6. The burner according to claim 5, wherein the third cylinder has an inner wall and an outer wall, and a portion of the protective air flows between the inner wall and the outer wall and then passes between the second cylinder and the third cylinder to be supplied to the combustion zone.

7. The burner according to any one of claims 1 to 4, wherein the gaseous fuel is hydrogen.

8. A combustion device comprising a plurality of burners according to any one of claims 1 to 4.

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