Burner

Abstract

To provide a burner that can be made compact and can be operated even when ammonia, which is one of the flame-retardant fuels, is used as fuel. [Solution] The burner (1) has a burner internal unit (2) and a housing pipe (3), and upstream of the burner internal unit (2) there is formed an upstream space (10) to which air A is supplied from an air supply device (9), and an intermediate flow path (11). The burner internal unit (2) comprises a tubular space (20), a combustion tube base (21), a plurality of swirl vanes (22) for forming a swirl flow, an annular plate (23), an inter-blade flow path (24), an air inflow restriction part (25) for restricting the inflow of air A, and a fuel supply part (4) comprising at least one of a first fuel supply part (41) that supplies a first fuel (F1) into the combustion tube base (21) and a second fuel supply part (41) that supplies a second fuel (F2) into the inter-blade flow path (24) etc. In the burner (1), a swirl flow is formed in the tubular space (20) by a gas flow that passes through the inter-blade flow path (24) and is ejected into the tubular space (20).

Description

[Technical Field]

[0001] The present invention relates to a burner. [Background technology]

[0002] Conventionally, as described in Patent Document 1, a combustor (burner) has been disclosed that has a gas supply pipe, a first supply section having a first gas flow path formed therein and connected to the gas supply pipe so as to extend tangentially to the side wall of the gas supply pipe, a second supply section having a second gas flow path formed therein and connected to the gas supply pipe so as to extend tangentially to the side wall of the gas supply pipe, and a combustion tube into which mixed gas is supplied from the gas supply pipe and a flame is formed inside the tube.

[0003] In this burner, the mixed gas is supplied to the gas supply pipe from two different tangential directions through the first and second gas passages, flows along the inner circumferential surface of the side wall of the gas supply pipe, and swirls inside the gas chamber. The mixed gas supplied to the gas supply pipe rises while swirling inside the gas chamber of the gas supply pipe, and is supplied to the combustion pipe where it is combusted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6846713 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional burner described above requires a first supply section and a second supply section connected to the gas supply pipe so as to extend in different tangential directions to the side wall of the gas supply pipe, which increases the outer diameter of the burner and limits the size of the burner.

[0006] In recent years, ammonia has been attracting attention as a fuel that does not emit carbon dioxide. Considering that efforts to utilize non-flammable fuels such as ammonia as fuel will progress in the future, it is desirable that at least ammonia can be burned as a fuel.

[0007] The present invention has been made in view of the above problems, and aims to provide a burner that can be made smaller and can be operated even when ammonia, which is a type of flame-retardant fuel, is used as fuel. [Means for solving the problem]

[0008] One aspect of the present invention is a burner internal unit; a housing tube that houses the burner internal unit therein, A burner in which an upstream space to which air is supplied from an air supply device is formed upstream of the burner internal unit as viewed in the direction of the burner central axis, The burner internal unit comprises: a tubular space provided in the center of the unit; a combustion tube base portion having a bottom and a tubular shape, the combustion tube base portion being connected to one end of the tubular space; a plurality of swirl vanes for forming a swirl flow provided so as to surround the outer periphery of the tubular space; an annular plate member provided at the tip of the unit and fixing a side edge of each of the swirl vanes on the tip side of the unit; inter-blade flow passages formed between adjacent swirl vanes; an air inflow restriction portion for restricting the inflow of the air from a portion of each inter-blade passage extending from a midpoint of a side end surface on the upstream space side to the combustion tube base, The burner is an intermediate flow passage communicating the upstream space with the inter-blade flow passage is formed between the combustion tube base and the housing pipe, the combustion tube further includes a fuel supply unit including at least one of a first fuel supply unit capable of supplying a first fuel into the combustion tube base and a second fuel supply unit capable of supplying a second fuel to at least one selected from the inter-blade flow passage, the intermediate flow passage, the upstream space, and the tubular space, In each of the inter-blade flow passages, inner surfaces of the adjacent swirl vanes on the flow passage side define each of the inter-blade flow passages, a gas flow passing through the inter-blade passage and ejected into the tubular space forms a swirling flow in the tubular space; It's in Burna. [Effects of the Invention]

[0009] The burner has the above-described configuration. In the burner, air sent from an air supply device such as a blower flows into an upstream space formed upstream of the burner internal unit as viewed in the burner central axis direction. The air that flows into the upstream space flows toward the burner internal unit located downstream of the upstream space as viewed in the burner central axis direction. The air then flows through an intermediate passage formed between the housing tube and the combustion tube base of the burner internal unit and reaches the side end faces of the upstream space side of multiple inter-blade passages formed between the multiple swirl vanes. Here, the side end face of each inter-blade passage on the upstream space side is provided with an air inflow restriction portion that restricts air inflow from a portion extending from the middle of the side end face to the combustion tube base. Therefore, air flows into the inter-blade passage from a portion of the side end face on the upstream space side of each inter-blade passage that does not have an air inflow restriction portion, passes through the inter-blade passage, and is ejected into the tubular space. In other words, the air that reaches the side end face of the inter-blade flow passage on the upstream space side is bent by the air inflow restriction portion so that its direction of travel is approximately perpendicular to the direction of the burner central axis, and then flows into the inter-blade flow passage, passing through the inter-blade flow passage and ejected into the tubular space.

[0010] In the burner, a fuel supply unit supplies at least one of a first fuel and a second fuel. That is, when the first fuel supply unit supplies the first fuel into the combustion tube base, the burner can eject a gas flow containing air into the tubular space, and then the first fuel and air are mixed. Also, when the second fuel supply unit supplies the second fuel into the inter-blade passage, the intermediate passage, or the upstream space, the burner can eject a gas flow containing a gas containing the second fuel and air into the tubular space. Also, when the second fuel supply unit supplies the second fuel into the tubular space, the burner can eject a gas flow containing air into the tubular space, and then the second fuel and air are mixed.

[0011] In the burner, a swirling flow is formed in the tubular space by the gas flow ejected into the tubular space through the multiple inter-blade flow passages. In other words, the burner can eject gas flows into the tubular space from the entire circumference. As described above, the burner does not have, as in the prior art, two gas supply pipes for supplying premixed gas that extend tangentially outside the peripheral wall of the housing tube. Therefore, the outer diameter of the burner can be reduced, allowing for a more compact burner. Furthermore, the burner can ignite the fuel contained in the swirling flow using an ignition electrode, a flame rod, an ignition ground electrode, or the like, thereby forming a flame by combustion of the fuel in the swirling flow, even when ammonia, a type of non-flammable fuel, is used as the fuel.

[0012] Therefore, the burner can be made smaller and can be operated even when ammonia, which is one of the flame-retardant fuels, is used as the fuel. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view of a burner according to an embodiment to which an air supply device is attached. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a cross section of the burner according to the embodiment of FIG. [Figure 3] FIG. 3 is a perspective view of a burner internal unit included in the burner according to the embodiment. [Figure 4] FIG. 4 is a perspective view of a housing tube of the burner according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view taken along the line VV of a burner according to an embodiment to which an air supply device is attached. [Figure 6] FIG. 6 is a cross-sectional view taken along the line VI-VI of the burner according to the embodiment to which the air supply device is attached. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII of the burner according to the embodiment to which the air supply device is attached. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII of the burner according to the embodiment to which the air supply device is attached. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX of the burner according to the embodiment to which the air supply device is attached. [Figure 10] FIG. 10 is a cross-sectional view taken along the line XX of the burner according to the embodiment to which the air supply device is attached. [Figure 11] FIG. 11 is a perspective view of a burner internal unit included in a burner according to an embodiment that was actually fabricated, viewed obliquely from behind the burner. [Figure 12] FIG. 12 is a perspective view of a burner internal unit included in a burner according to an embodiment that was actually fabricated, viewed obliquely from the front of the burner. [Figure 13] FIG. 13 is a perspective view of a burner according to an embodiment that was actually fabricated, in which the burner internal unit is removed from the housing pipe, as viewed obliquely from behind the burner. [Figure 14] FIG. 14 is a diagram for explaining a method for calculating the swirl number S and the inflow swirl number S′ of the swirl flow formed in the burner according to the embodiment having flat plate-shaped swirl vanes. [Figure 15] FIG. 15 is a diagram for explaining a method for calculating the swirl number S and the inflow swirl number S' of the swirl flow formed in the burner according to the embodiment having swirl vanes in the shape of a flat curved plate. [Figure 16] FIG. 16 is an explanatory diagram that schematically shows the configuration of the burner according to the embodiment shown in FIGS. [Figure 17] FIG. 17 is an explanatory diagram that schematically shows a modified example of the configuration of the burner according to the embodiment shown in FIGS. [Figure 18] FIG. 18 is an explanatory diagram that schematically shows another modified example of the configuration of the burner according to the embodiment shown in FIGS. [Figure 19] FIG. 19 is an explanatory diagram that schematically shows yet another modified example of the configuration of the burner according to the embodiment shown in FIGS. [Figure 20] FIG. 20 is an explanatory diagram that schematically shows yet another modified example of the configuration of the burner according to the embodiment shown in FIGS. [Figure 21] FIG. 21 is a diagram showing the appearance of a burner according to an embodiment that was actually fabricated for a combustion test and to which an air supply device was attached. [Figure 22] FIG. 22 is a diagram showing a design drawing (cross-sectional view) of a small combustion furnace fabricated for a combustion test of the burner according to the embodiment that was actually fabricated. [Figure 23] FIG. 23 shows a combustion test being carried out in which the burner according to the embodiment that was actually manufactured is set at the bottom end of a small combustion furnace so that a flame can be formed upward. [Figure 24] FIG. 24 is an enlarged view of a flame produced by ammonia fuel observed from the side of the burner, in which the tip of the combustion tube and the outer tube are made of a double-tube structure of quartz glass pipes. [Figure 25] FIG. 25 is a diagram showing the discharge concentration of nitric oxide NO obtained in the experimental example. [Figure 26] FIG. 26 shows the emission concentration of nitrogen dioxide NO2 obtained in the experimental example. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of a burner according to the present invention will be described in detail below with reference to the drawings. Note that the burner according to the present invention is not limited to the examples shown in the following embodiment. Furthermore, the lower and upper limits of the numerical ranges shown below can be arbitrarily combined, including the values ​​described in the experimental examples (omitted below).

[0015] The burner of this embodiment will be described with reference to Figures 1 to 18. Figures 11 to 13 show a portion of a burner that was actually fabricated based on Figures 1 to 10, and in describing the burner of this embodiment, these drawings of the actually fabricated burner can also be referred to as appropriate.

[0016] As illustrated in FIGS. 1 to 13, the burner 1 of this embodiment includes a burner internal unit 2, a housing tube 3, and a fuel supply unit 4. The burner internal unit 2 includes a tubular space 20, a combustion tube base 21, multiple swirl vanes 22, an annular plate 23, an inter-blade flow passage 24, and an air inflow restriction unit 25. The burner 1 includes an upstream space 10 and an intermediate flow passage 11. In the burner 1, a swirl flow is formed in the tubular space 20 by a gas flow that passes through the inter-blade flow passage 24 and is ejected into the tubular space 20. The burner 1 can be primarily made of a metal material such as stainless steel, a heat-resistant material such as ceramic (including glass), or a combination of these. Hereinafter, the flame-forming side of the burner 1 is referred to as the front of the burner 1, and the opposite side as the rear of the burner 1. Furthermore, from a predetermined reference position, the side from which air A flows is referred to as the upstream side, and the side from which air A flows is referred to as the downstream side.

[0017] The housing tube 3 is for housing the burner internal unit 2 therein. The housing tube 3 is formed in a tubular shape. The tube axis of the housing tube 3 coincides with the burner central axis L of the burner 1. The burner internal unit 2 is housed in the housing tube 3 from an opening 30 that opens at the rear end of the housing tube 3.

[0018] The upstream space 10 is formed upstream of the burner internal unit 2 when viewed in the direction of the burner central axis L. In Figs. 1 to 13, an example is shown in which the upstream space 10 is formed inside the housing pipe 3. Air A is supplied to the upstream space 10 from an air supply device 9. The air A supplied to the upstream space 10 is used at least as primary air A1.

[0019] In the burner 1, as illustrated in, for example, FIGS. 2, 4, and 6, an example is shown in which an air inlet 32 ​​is formed in a portion of the peripheral wall of the housing tube 3, allowing air A supplied from the air supply device 9 to flow into the upstream space 10. With this configuration, the air supply device 9 is attached to the burner 1 on the burner side, and air A can be supplied to the upstream space 10 through the air inlet 32 ​​formed in a portion of the peripheral wall of the housing tube 3, making it easier to shorten the length of the burner 1 in the burner axial direction L, including the air supply device 9. In the burner 1 illustrated in FIGS. 1 to 13, a burner rear lid 31 is disposed at the rear end of the housing 7 (described in detail later). Therefore, it is possible to block the intrusion of outside air through the opening 30 at the rear end of the housing tube 3.

[0020] Examples of the air supply device 9 that can be used in the burner 1 include a compressor and an air supply device with a supply pressure lower than that of a compressor. From the viewpoint of reducing the size and cost of the burner 1, the air supply device 9 is preferably one with a supply pressure lower than that of a compressor. The supply pressure of air A by an air supply device 9 with a supply pressure lower than that of a compressor can be specifically set to less than 100 kPa. Examples of such air supply devices 9 include air supply devices that send air, such as a blower. A blower is a device that can normally send air A at a pressure of 10 kPa or higher and lower than 100 kPa.

[0021] From the viewpoint of promoting the inflow of air into the inter-blade flow passage 24 in which the air inflow restriction portion 25 is formed and facilitating the strengthening of the flow of gas passing through the inter-blade flow passage 24 and ejected into the tubular space 20, the burner 1 is preferably configured so that the air A supplied from the air supply device 9 and flowing into the upstream space 10 through the air inlet 32 ​​swirls within the upstream space 10. Specifically, such a configuration can be realized by, for example, arranging the air inlet 32 ​​relative to the air supply device 9 so that the air A supplied from the air supply device 9 swirls within the housing pipe 3, as exemplified in Fig. 6 and the like.

[0022] The burner 1 can be configured to have a housing 7 that covers the housing pipe 3, from the viewpoint of facilitating the attachment of accessories to the burner 1, such as an air supply device 9. The air supply device 9 can be integrally connected to the peripheral wall of the housing 7, from the viewpoint of packaging the burner 1, etc.

[0023] When the burner 1 has a housing 7, it is preferable that a cooling space 71 to which part of the air from the air supply device 9 is supplied is formed between the peripheral wall of the housing pipe 3 and the housing 7, as exemplified in Fig. 2 etc. According to this configuration, it becomes possible to cool the housing pipe 3, the burner internal unit 2, etc. by the air flowing in the cooling space 71.

[0024] As exemplified in Figures 8 and 12, the tubular space 20 is provided in the unit central portion, which is the central portion of the burner internal unit 2. The unit central portion can also be called the unit center portion. The tubular space 20 includes the central axis of the burner internal unit 2 and is configured as a space exhibiting a tubular shape around this central axis. Here, the tube axis of the tubular space 20 coincides with the central axis of the burner internal unit 2. Furthermore, the tube axis of the tubular space 20 and the central axis of the burner internal unit 2 coincide with the burner central axis L of the burner 1.

[0025] The combustion tube base 21 is formed in a tubular shape with a bottom. The combustion tube base 21 is connected to one end of the tubular space 20. Specifically, the combustion tube base 21 is connected to the tubular space 20 by having an opening of the combustion tube base 21 connected to the rear end of the tubular space 20. The tube axis of the combustion tube base 21 coincides with the burner central axis L of the burner 1.

[0026] The multiple swirl vanes 22 are used to form a swirling flow, that is, to form a swirling flow within the tubular space 20. Each swirl vane 22 is provided so as to surround the outer periphery of the tubular space 20. When housed within the housing pipe 3, each swirl vane 22 is disposed between the housing pipe 3 and the tubular space 20 so as to surround the outer periphery of the tubular space 20.

[0027] Specifically, the swirl vanes 22 are arranged at predetermined intervals along the circumferential direction of the tubular space 20. The shape of the swirl vanes 22 is not particularly limited, but here, an example is shown in which the swirl vanes 22 are formed into a rectangular shape from a curved flat plate material. As exemplified in FIG. 14, the swirl vanes 24 may be formed from a flat plate material. Furthermore, although not shown, the swirl vanes 22 may be formed from a curved plate that is entirely curved. In order to impart turbulence and velocity non-uniformity to the swirling flow within the tubular space 20 for the purpose of promoting mixing and combustion, the spacing and angles of the swirl vanes 22 may be made non-uniform, and plate shapes such as flat plates, curved plates, and curved plates may be mixed.

[0028] As exemplified in Figures 3, 11, 12, etc., the annular plate material 23 is formed from a plate material having an annular shape. Here, the inner diameter of the annular plate material 23 is set to be equal to the diameter (outer diameter) of the tubular space 20. The outer diameter of the annular plate material 23 is set to be slightly smaller than the inner diameter of the housing tube 3. The annular plate material 23 is provided at the unit tip portion, which is the tip portion of the burner internal unit 2, and fixes the side edges of each swirl vane 22 on the unit tip side. Note that each swirl vane 22 can be fixed to the annular plate material 23 at a predetermined angle at which the swirl number of the swirling flow in the tubular space 20 (described in detail later) is a value within an optimum range.

[0029] The inter-blade flow passages 24 are flow passages formed between adjacent swirl vanes 22. The inter-blade flow passages 24 connect the intermediate flow passages 11 (described in detail later) with the tubular space 20. Specifically, each inter-blade flow passage 24 can be formed by being mainly partitioned by the inner surfaces of the flow passage sides of the adjacent swirl vanes 22 and the annular plate member 23, for example.

[0030] As illustrated in Figures 3 and 11, the air inflow restriction portion 25 is provided from the middle of the side end face of each inter-blade passage 24 on the upstream space 10 side to the combustion tube base 21. This air inflow restriction portion 25 is a portion for restricting the inflow of air A from the portion of each inter-blade passage 24 on the upstream space 10 side to the combustion tube base 21. That is, in the burner 1, since the burner internal unit 2 has the air inflow restriction portion 25, the air A flowing from the upstream space 10 side mainly flows into the inter-blade passage 24 from the portion of the side end face of each inter-blade passage 24 on the upstream space 10 side where the air inflow restriction portion 25 is not present. The provision of the air inflow restriction portion 25 makes it possible to significantly increase the length of the effective contraction flow path of each inter-blade passage 24, and thus a strong, rectified swirl flow can be formed in the tubular space 20 while maintaining a compact configuration that does not increase the outer diameter of the burner internal unit 2 or the burner 1.

[0031] In the burner 1, an intermediate flow passage 11 is formed between the combustion tube base 21 of the burner internal unit 2 and the housing tube 3. The intermediate flow passage 11 is a flow passage for communicating the upstream space 10 with the inter-blade flow passage 24. Specifically, the intermediate flow passage 11 is composed of a gap formed between the outer peripheral surface of the combustion tube base 21 and the inner peripheral surface of the housing tube 3.

[0032] The burner 1 has a fuel supply section 4 that is composed of at least one of a first fuel supply section 41 and a second fuel supply section .

[0033] The first fuel supply unit 41 is a portion capable of supplying the first fuel F1 into the combustion tube base 21. The position from which the first fuel F1 is supplied into the combustion tube base 21 is not particularly limited. From the viewpoints of making it easier to achieve pre-mixing and to prevent flashback, the first fuel supply unit 41 is preferably configured to be able to supply the first fuel F1 from the center of the bottom 211 of the combustion tube base 21. The center of the bottom 211 refers to a region within (including on) a circle whose center is the center point of the bottom 211 (the point where the bottom 211 intersects with the tube axis of the combustion tube base 21) and whose radius is 1 / 2 the radius of the bottom 211, preferably 1 / 3 the radius of the bottom 211.

[0034] More specifically, as illustrated in FIG. 2 and other figures, an example is shown in which a first fuel nozzle 41b provided at the tip of a pipe 41a connected to a supply source (not shown) of the first fuel F1 is inserted into the center of the bottom 211 of the combustion tube base 21, and the first fuel F1 can be mixed into the combustion tube base 21 through a nozzle hole 41c. The direction of the nozzle hole 41c may be tilted relative to the jet of the first fuel F1 supplied from the first fuel nozzle 41 through the nozzle hole 41c to impart not only a radial velocity component but also a swirling velocity component, thereby reinforcing the swirling flow formed in the tubular space 20 or causing the flows to collide and reinforce mixing. Alternatively, the swirling flow and mixing may be reinforced by shifting the first fuel nozzle 41 from the center of the bottom 211. Compared to fuels with a large theoretical air volume (volume ratio of air to fuel at the time of theoretical mixing), such as propane or methane, fuels with a small theoretical air volume, such as ammonia or hydrogen, have a large effect in reinforcing the swirl flow due to the fuel jet, so setting the fuel jet is important. In addition to reinforcing the swirl, the fuel jet can also be used to promote mixing of the fuel and air by colliding with the air swirl.

[0035] The second fuel supply unit 42 is a portion capable of supplying the second fuel F2 to at least one selected from the inter-blade passage 24, the intermediate passage 11, the upstream space 10, and the tubular space 20. The position at which the second fuel F2 is supplied to the above-mentioned portions is not particularly limited. For example, when the second fuel F2 is supplied to the inter-blade passage 24, the second fuel supply unit 42 is preferably configured to supply the second fuel F2 to any portion of the inter-blade passage 24 from a portion of the side end face of the inter-blade passage 24 on the upstream space 10 side that is not covered by the air inflow restrictor 25, from the viewpoint of the mixability of the second fuel F2 and the air A in the inter-blade passage 24.

[0036] When the second fuel F2 is supplied into the inter-blade passages 24, specifically, for example, as illustrated in Fig. 2 and the like, second fuel nozzles 42b connected directly or indirectly to pipes 42a connected to a supply source (not shown) of the second fuel F2 may be inserted into the inter-blade passages 24. In this case, the second fuel nozzles 42b may be disposed in all of the plurality of inter-blade passages 24, or may be disposed in some of the plurality of inter-blade passages 24. Note that here, as illustrated in Fig. 8 and the like, an example is shown in which the second fuel nozzles 42b are disposed in each of the plurality of inter-blade passages 24.

[0037] 2, 7, and the like, from the viewpoint of simplifying the structure for supplying the second fuel F2 into the inter-blade flow passages 24, the burner 1 may also employ a configuration in which a second fuel common rail 42d arranged in the circumferential direction of the combustion tube base 21 is connected to a pipe 42a connected to a supply source (not shown) of the second fuel F2, and a plurality of second fuel nozzles 42b are connected to the second fuel common rail 42d. With this configuration, the second fuel F2 is supplied from the pipe 42a to the second fuel common rail 42d, and the second fuel F2 flowing through the second fuel common rail 42d can be distributed to each second fuel nozzle 42b. Therefore, with this configuration, the structure inside the housing pipe 3 can be simplified compared to a case in which each second fuel nozzle 42b is connected to a pipe 42a connected to a supply source (not shown) of the second fuel F2. Furthermore, by extending the tips of the plurality of second fuel nozzles 42b to the outlet of the inter-blade passage 24, it is possible to realize pre-mixed combustion with good mixing characteristics without the possibility of flashback. The tip of the fuel nozzle 42b may be, for example, a flat tube, in accordance with the shape of the outlet of the inter-blade passage 24. Furthermore, if the plurality of second fuel nozzles 42b are formed from an elastic tube, they can be attached to and detached from the inter-blade passage 24 while the fuel common rail 42d and the fuel nozzles 42b remain connected, thereby providing a burner 1 that is easy to manufacture and maintain.

[0038] The burner 1 described above can burn fuel as follows. In the burner 1, air A (primary air A1) sent from an air supply device 9 such as a blower flows into an upstream space 10 located upstream of the burner internal unit 2 as viewed in the direction of the burner central axis L within the housing tube 3 that houses the burner internal unit 2. The air A that has flowed into the upstream space 10 flows toward the burner internal unit 2 located downstream of the upstream space 10 as viewed in the direction of the burner central axis L. The air A then flows through an intermediate flow passage 11 formed between the housing tube 3 and a combustion tube base 21 of the burner internal unit 2, and reaches the side end faces of the multiple inter-blade flow passages 24 on the upstream space 10 side. Here, an air inflow restriction section 25 is provided on the side end face on the upstream space 10 side of each inter-blade flow passage 24 to restrict the inflow of air A from a portion extending from the middle of the side end face to the combustion tube base 21. Therefore, the air A flows into the inter-blade passages 24 from a portion of the side end face of each inter-blade passage 24 on the upstream space 10 side where there is no air inflow restricting portion 25, passes through the inter-blade passages 24, and is ejected into the tubular space 20. In other words, the air A that has reached the side end face of the inter-blade passage 24 on the upstream space 10 side is bent by the air inflow restricting portion 25 at a substantially right angle to the direction of the burner central axis L, flows into the inter-blade passages 24, and is ejected into the tubular space 20 through the inter-blade passages 24.

[0039] In the burner 1, the fuel supply unit 4 supplies at least one fuel selected from a first fuel F1 and a second fuel F2. That is, when the first fuel supply unit 41 supplies the first fuel F1 into the combustion tube base 21, the burner 1 can eject a gas flow containing air A into the tubular space 20, and then the first fuel F1 and the air A are mixed. When the second fuel supply unit 42 supplies the second fuel F2 into the inter-blade passage 24, the intermediate passage 11, or the upstream space 10, the burner 1 can eject a gas flow containing a gas containing the second fuel F2 and air A into the tubular space 20. When the second fuel supply unit 42 supplies the second fuel F2 into the tubular space 20, the burner 1 can eject a gas flow containing air A into the tubular space 20, and then the second fuel F2 and the air A are mixed.

[0040] In the burner 1, a swirling flow is formed in the tubular space 20 by the above-mentioned gas flow that passes through the multiple inter-blade passages 24 and is ejected into the tubular space 20. That is, the burner 1 can eject a gas flow into the tubular space 20 from the entire circumference of the tubular space 20. As described above, the burner 1 does not have, for example, two gas supply pipes for supplying premixed gas that extend tangentially outside the peripheral wall of the housing tube 3 as in the conventional technology, so that the outer diameter of the burner can be reduced, and the burner 1 can be made more compact. Furthermore, the burner 1 can form a flame (sometimes referred to as a tubular flame or a swirl flame) by burning the fuel in the swirling flow, even when ammonia, which is a type of non-flammable fuel, is used as the fuel, by igniting the fuel contained in the swirling flow using the ignition electrode 901, the flame rod 902, the ignition earth electrode 903, etc.

[0041] Therefore, the burner 1 can be made compact and can be operated even when ammonia, which is one of the flame-retardant fuels, is used as the fuel.

[0042] The burner 1 is capable of burning at least ammonia as fuel, but the fuel is not limited to ammonia. In addition to ammonia, examples of fuels that can be used in the burner 1 include gas fuels such as hydrogen and various hydrocarbons, atomized liquid fuels and volatile fuels such as heavy oil and kerosene, and powdered fuels such as pulverized coal, and these can be used alone or in combination. When at least ammonia is used as fuel, combustion does not involve the emission of carbon dioxide, which can contribute to the realization of a decarbonized society.

[0043] In addition to the configuration described above, the burner 1 can also be configured to have a combustion tube tip 5, as exemplified in Figure 2 and the like. The combustion tube tip 5 is connected to the other end of the tubular space 20 and is formed in a tubular shape. The other end of the tubular space 20 is the end opposite the end on the combustion tube base 21 side, of both ends of the tubular space 20. When the burner 1 has the combustion tube tip 5, the swirling flow formed in the tubular space 20 flows forward while swirling along the inner wall surface of the combustion tube tip 5, making it easier to stabilize the tubular flame.

[0044] The length of the combustion tube tip 5 is not particularly limited, but from the viewpoint of stabilizing the tubular flame, it is preferably at least 0.2 times the inner diameter of the tubular space 20, more preferably at least 0.3 times the inner diameter of the tubular space 20, and even more preferably at least 0.4 times the inner diameter of the tubular space 20. Furthermore, from the viewpoint of reducing the size of the burner 1, the length of the combustion tube tip 5 is preferably at most 4 times the inner diameter of the tubular space 20, more preferably at most 3 times the inner diameter of the tubular space 20, and even more preferably at most 2 times the inner diameter of the tubular space 20.

[0045] When the burner 1 has a combustion tube tip 5, the burner 1 can be configured to further have a tubular outer tube 6 on the outer periphery of the combustion tube tip 5, as exemplified in Fig. 2 etc. When the burner 1 has the combustion tube tip 5 and the outer tube 6, it becomes possible to use the space between the combustion tube tip 5 and the outer tube 6 as a secondary air flow path 8. Therefore, in this case, by flowing secondary air A2 through the secondary air flow path 8, it is possible to improve the flame stability of the flame ejected from the combustion tube tip 5.

[0046] In this case, for example, by configuring the secondary air A to flow into the inter-blade flow passage 24 so that a portion of the air A can flow into the secondary air passage 8 through the communication holes 231 formed in the annular plate 23, the secondary air A2 can be supplied to the secondary air passage 8. Specifically, as illustrated in FIGS. 2 to 4, 12, and 13, a plurality of communication holes 231 are formed in the outer edge of the annular plate 23. The shape of the communication holes 231 is not particularly limited. Here, an example is shown in which a plurality of communication holes 231 formed in a recessed shape in the outer edge of the annular plate 23 are spaced apart at predetermined intervals in the circumferential direction. Furthermore, as illustrated in FIGS. 2 to 4, and 13, a housing-pipe-side annular plate 26 is provided within the front end of the housing tube 3, against which the annular plate 23 of the burner internal unit 2 housed in the housing tube 3 abuts. A plurality of communication holes 261 are formed in the outer edge of the housing tube-side annular plate 26. The shape of the communication holes 261 is not particularly limited. Here, an example is shown in which a plurality of communication holes 261 are formed in a recessed shape at the outer edge of the housing-pipe-side annular plate member 26, spaced apart at a predetermined interval in the circumferential direction. In addition, the shape of the communication holes 231 of the annular plate member 23 and the shape of the communication holes 261 of the housing-pipe-side annular plate member 26 are made to be the same shape.

[0047] According to the above configuration, by rotating the burner internal unit 2 housed in the housing tube 3 in the circumferential direction, when the communication holes 231 of the annular plate member 23 and the communication holes 261 of the housing-tube-side annular plate member 26 are aligned with each other, part of the air A (primary air A) to be flowed into the inter-blade passage 24 flows as secondary air A2 into the secondary air passage 8. On the other hand, when the communication holes 231 of the annular plate member 23 and the communication holes 261 of the housing-tube-side annular plate member 26 are not aligned with each other, it is possible to prevent part of the air A (primary air A) to be flowed into the inter-blade passage 24 from flowing as secondary air A2 into the secondary air passage 8. Therefore, according to the above configuration, it is possible to select whether or not to supply secondary air A2 by the simple method of rotating the burner internal unit 2 in the circumferential direction. In addition, by changing the overlapping range between the communication hole 231 of the annular plate material 23 and the communication hole 261 of the housing pipe side annular plate material 26, it is possible to easily adjust the amount of air flowing into the secondary air flow path 8.

[0048] When the burner 1 has a combustion tube tip 5 and an outer tube 6, as exemplified in FIG. 2 and the like, the outer tube 6 is disposed on the outer periphery of the combustion tube tip 5, thereby forming a double-tube structure. As described above, the space between the combustion tube tip 5 and the outer tube 6 forming the double-tube structure can be used as a secondary air flow path 8. In this case, the tips of the combustion tube tip 5 and the outer tube 6 can be closed with annular lids 51. Furthermore, a plurality of secondary air outlet holes 52 can be formed on the inner circumferential surface of the combustion tube tip 5, which serves as the inner tube, near the front end. As a result, air A (secondary air A2) flowing in the secondary air flow path 8 flows into the combustion tube tip 5 from the plurality of secondary air outlet holes 52 formed on the inner circumferential surface of the combustion tube tip 5 near the front end, and is used for flame combustion.

[0049] Specifically, Figure 2 and other figures show an example in which the combustion tube tip portion 5 and the outer pipe 6 are formed so as to be separable into two, a rear side and a front side, with the mounting plate 95 as the boundary. As illustrated in Figures 2, 9, and other figures, an example is shown in which, on the rear side of the mounting plate 95, the combustion tube tip portion 5 and parts of the outer pipe 6 are sandwiched and fixed between the mounting plate 95 and the burner internal unit 2 and the housing 7 by two fixing members 96 arranged spaced apart from each other along the outer periphery of the outer pipe 6. Furthermore, as illustrated in Figures 2, 10, and other figures, an example is shown in which, on the front side of the mounting plate 95, the rear end sides of the combustion tube tip portion 5 and the remaining parts of the outer pipe 6 are fixed to the mounting plate 95. The mounting plate 95 has a communication hole 951 that communicates the secondary air flow path 8 formed on the rear side of the mounting plate 95 with the secondary air flow path 8 formed on the front side of the mounting plate 95.

[0050] When the combustion tube tip portion 5 and the outer tube 6 are formed as two separate pieces, one on the rear side and one on the front side, separated by the mounting plate 95 as described above, the material of the combustion tube tip portion 5 and the outer tube 6 on the rear side of the mounting plate 95 can be made of heat-resistant glass such as quartz glass. The material of the combustion tube tip portion 5 and the outer tube 6 on the front side of the mounting plate 95 may be made of heat-resistant glass such as quartz glass, as described above, or may be made of a metal material such as stainless steel.

[0051] Although an example has been shown in which the combustion tube tip portion 5 and the outer tube 6 can be divided into two portions, a rear side and a front side, separated by the mounting plate 95, the mounting plate 95 is not necessarily required, and the combustion tube tip portion 5 and the outer tube 6 may each be formed continuously. Also, the tips of the combustion tube tip portion 5 and the outer tube 6 may not be closed by the annular lid portion 51, and secondary air A2 may be allowed to flow out from those portions. In this case, secondary air outflow holes 52 may or may not be formed.

[0052] In addition to the above-described configuration, the burner 1 can also be configured to have a turbulence generating section (not shown) at a position where it can turbulently generate turbulence in the gas flow ejected into the tubular space. With this configuration, the gas flow ejected into the tubular space 20 hits the turbulence generating section, generating turbulence in the gas flow and making it possible to turn the swirling flow into turbulence. Therefore, in this case, there are advantages such as shortening the flame that is formed, shortening the length of the burner 1, and promoting the mixing of the fuel and air A.

[0053] The configuration of the turbulence generating section is not particularly limited as long as it can cause turbulence in the gas flow injected into the tubular space 20. The turbulence generating section can be configured, for example, by combining uneven sections or various structures. The turbulence generating section can be configured by providing a ring member (not shown) in the circumferential direction and perpendicular to the burner central axis L at a location in the tubular space 20 near the outer periphery of the tubular space 20. Note that "perpendicular to the burner central axis L" does not only mean that the ring member intersects with the burner central axis L at a geometrically strict right angle, but also means that the ring member intersects with the burner central axis L at an angle in the range of -15 degrees to 15 degrees relative to the right angle.

[0054] Furthermore, a turbulence generating section can also be configured by forming a convex portion (not shown) that protrudes into the inter-blade flow passage 24 on a flat portion of the swirl vane 22. Note that the convex portion can be suitably formed on a portion of the flat surface of the swirl vane 22 that is closer to the tubular space 20, from the viewpoint of efficiently turbulenting the gas flow ejected into the tubular space 20. The number of convex portions is not particularly limited, and one or more convex portions may be formed per inter-blade flow passage 24 (per swirl vane 22).

[0055] Furthermore, a turbulent flow generating section can also be configured by providing a columnar member (not shown) parallel to the burner central axis L and extending in the circumferential direction, for example, in a portion of the tubular space 20 near the outer periphery of the tubular space 20 or at the tip of each inter-blade flow passage 24. Note that "parallel to the burner central axis L" does not only mean being geometrically strictly parallel to the burner central axis L, but also means being inclined at an angle in the range of -15 degrees to 15 degrees with respect to the burner central axis L.

[0056] As described above, the turbulence generating section 28 can be composed of a structural part (such as a ring member) that is perpendicular to the burner central axis L and in the circumferential direction, a structural part (such as a convex part) that is perpendicular to the burner central axis L and in the flow path width direction of the inter-blade flow path 24, a structural part (such as a columnar member) that is parallel to the burner central axis L, or a combination of these.

[0057] In addition to the above-described configuration, the burner 1 can be configured to have an observation window (not shown) for observing the flame formed inside the burner 1. In this case, the flame formed inside the burner 1 can be observed from outside the burner 1 through the observation window. Therefore, for example, when ammonia, which is a flame-retardant fuel, is used as the fuel, it is particularly useful because the combustion state can be easily confirmed.

[0058] The observation window can be formed, for example, in at least a portion of the peripheral wall of the combustion tube tip 5. In this case, if the burner 1 has an outer tube 6 on the outer periphery of the combustion tube tip 5, a second observation window can be formed in at least a portion of the outer tube 6 so as to correspond in position to the first observation window formed in the combustion tube tip 5. The observation window can also be configured to include a third observation window formed in at least a portion of the peripheral wall of the combustion tube base 21, and a fourth observation window formed in at least a portion of the housing tube 3 so as to correspond in position to the third observation window formed in the combustion tube base 21. In this case, if the burner 1 has a housing 7 on the outer periphery of the housing 3, a fifth observation window can be formed in at least a portion of the housing 7 so as to correspond in position to the fourth observation window formed in the housing 3.

[0059] Furthermore, as illustrated in Figure 2, for example, if the combustion tube tip 5 and the outer tube 6 are divided into two parts, one at the rear side and one at the front side, separated by the mounting plate 95, the combustion tube tip 5 and the outer tube 6 on the rear side of the mounting plate 95 can be made of a material such as heat-resistant glass, such as quartz glass, and this part can be used as an observation window to observe the flame formed inside the burner 1.

[0060] Furthermore, it is preferable that the burner 1 can set the swirl number S of the swirling flow in the tubular space 20 to 0.79 or more (the inflow swirl number S' to 0.49 or more). When the swirl number is within the above range, the flame stability of the tubular flame formed by the combustion of the fuel contained in the swirling flow is good, making it easier to achieve stable combustion.

[0061] From the viewpoint of improving the flame stability of the tubular flame, the swirl number S (inflow swirl number S') is more preferably S = 1.4 or more (S' = 0.58 or more), even more preferably S = 2.2 (S' = 0.62 or more), and even more preferably S = 4.5 or more (S' = 0.65 or more). From the viewpoint of avoiding an increase in pressure loss due to a reduction in the inflow area during high swirl, the swirl number S (inflow swirl number S') can be, for example, S = 7.0 or less (S' = 0.66 or less).

[0062] The swirl number S (the inflow swirl number S') is derived from the geometric shape of the swirl vanes 22 when the burner 1 is not burning, and is defined as follows: The inflow swirl number S', listed together with the swirl number S, is based on the definition in the reference ("Aerodynamics of Bear / Cigar Combustion," edited by Iinuma Kazuo, translated by Tanaka Ryoichi, 1985, Energy Conservation Center).

[0063] Fig. 14 shows an example of the configuration and dimensions of a burner 1 having flat plate-shaped swirl vanes 22, which is used to explain the method of calculating the swirl number S of the swirl flow and the inflow swirl number S'. Also, Fig. 15 shows an example of the configuration and dimensions of a burner 1 having flat curved plate-shaped swirl vanes 22, which is used to explain the method of calculating the swirl number S of the swirl flow and the inflow swirl number S'. These Figs. 14 and 15 are drawings depicting the state of the jet supply cross section perpendicular to the tube axis of the combustion tube base 21.

[0064] In the burner 1 exemplified in Figures 14 and 15, a fluid is supplied to a tubular space 20 as a swirling jet having a tangential velocity component from the outer peripheral surface of the tubular space 20. The jet is supplied in the axial direction of the tubular space 20 over a distance of B [m]. In order to obtain a strong swirl, it is better for the fluid not to have a velocity component in the axial direction (z direction) when it flows into the tubular space 20, and this case will be considered here. The burner 1 (here, the radius R of the tubular space 20) d= radius of the combustion tube cylindrical wall at the combustion tube base 21), the swirling flow (fluid density ρ, total flow rate Q) is ejected at a velocity V from the outlet of the gap between multiple (N pieces, 16 pieces in the figure and in the actual fabricated example) flat plate swirl vanes (Fig. 14) or flat curved plate swirl vanes (Fig. 15), that is, from the outlet of the inter-blade flow passage 24. The outlet flow passage width of the inter-blade flow passage 24 is assumed to be h. The ejection velocity V0 is given by V0=Q / (N×h×B)=(UπR d 2 ) / (N×h×B). The swirl vane 22 can rotate (or may be non-rotating) around an axis located at a position e from the tip of the vane, at a radial position Rp, with N rotation axis points (for example, Pv on the y-axis and its neighboring Pvn) spaced at equal angular intervals Apn° around the entire circumference, and the set angle is shown as Av° in the figure. Here, the outlet flow passage width h of the inter-blade flow passage 24 is calculated as the length of the line (outlet) connecting the tip E of <swirl vane 1> in the figure (radial position Re, angular position Ape° from the y-axis) to the foot N (radial position Rn) of a perpendicular line drawn from tip E to <swirl vane 2> (tip En) in the figure. Here, the midpoint between E and N on the surface of <swirl vane 2> (straight line N-En) is defined as M (radial position Rm, angular position Am° from the y-axis). Since the jet is ejected at an angle Af° with respect to the vector OM, the tangential component W0 of the jet is calculated as W0 = V0 × sin(Af°). The swirl number S and the inflow swirl number S', which are used as indicators of the swirl strength of a swirling jet, are calculated by the axial flux G of the angular momentum of the swirling flow as follows: φ and axial (z-direction) thrust G z However, since we are dealing with a flow inside a pipe here, the static pressure term can be ignored in the equation for axial thrust.

[0065]

number

[0066]

number

[0067] Here, U and W = W(r) are the axial and tangential components of the velocity in a cross section perpendicular to the tube axis, respectively. r is the radial coordinate with the tube center as the origin. ρ is the gas density, R d is the radius of the tubular space 20 (the radius of the cylindrical wall of the combustion tube at the base 21 of the combustion tube). If the axial velocity component U is considered to be uniform across the cross section, the axial thrust G z is expressed as follows:

[0068]

number

[0069] On the other hand, G φ In the integrand, two types of velocity distribution of W can be set as follows: (1) Focusing on the effect of the maximum peripheral velocity W0 of the inflow jet, W = W(r) is calculated from the velocity 0 at the center O of the tubular space 20 (combustion tube base 21) to the velocity at the cylindrical inner wall of the combustion tube (radius R d ) to W0, the rigid body rotation speed distribution W=(r / R d ) × W0 (drawn at the bottom of Figures 14 and 15 for reference). In this case, G φ is expressed as follows:

[0070]

number

[0071] Furthermore, W0 = V0 × sin(Af°), and V0 = Q / (N × h × B) = (UπR d 2 ) / (N×h×B), G φ is expressed as follows:

[0072]

number

[0073] Therefore, the swirl number S can be calculated using the following formula:

[0074]

number

[0075] (2) Integrating only the tangential velocity component W0 of the inflowing jet. In this case, G φ is expressed as follows:

[0076]

number

[0077] Therefore, the inflow swirl number S' can be calculated by the following formula.

[0078]

number

[0079] The configuration of the burner 1 described above using Figures 1 to 15 is shown in a schematic form in Figure 16. Below, modified examples of the burner 1 are shown in Figures 17 to 20 in comparison with the configuration of the burner 1 exemplified in Figure 16. The hatched areas in Figures 16 to 20 are fuel areas.

[0080] As illustrated in Fig. 17, the burner 1 may be configured so that a portion of the air A supplied from the air supply device 9 is directly supplied to the secondary air flow path 8. Note that "directly" here means without passing through the housing pipe 3. Specifically, for example, as illustrated in Fig. 17, the interior of the casing 7 and the secondary air flow path 8 may be configured to be communicable with each other, and a portion of the air A supplied from the air supply device 9 to the casing 7 may be directly supplied to the secondary air flow path 8 as secondary air A2. In this case, for example, the cooling space 71 in the casing 7 may be configured to be communicable with the secondary air flow path 8.

[0081] Furthermore, as illustrated in FIG. 19 , the burner 1 may have an intake port 81 at the rear end of the secondary air passage 8 or elsewhere to take in the air surrounding the burner 1 as secondary air A1. While air is typically introduced into the secondary air passage 8, fuel for additional combustion or a reducing gas for nitrogen oxide reduction may also be introduced. For example, when ammonia is used as fuel, lean combustion is achieved by a high-intensity swirl flow in the main combustion region, such as the tubular space 20 or the combustion tube base 21. Ammonia supplied to the secondary air passage 8 as both a fuel and a reducing agent is mixed with the air-excess combustion gas containing nitrogen oxides, thereby achieving both the effects of increased heat generation and reduced nitrogen oxides, thereby forming a single-fuel low-nitrogen oxide burner. In this case, the secondary air passage 8 serves as a passage through which the fuel and reducing gas flow. Therefore, the secondary air passage 8 is referred to as a fluid passage.

[0082] 18 and 19, the burner 1 can also be configured so that air A supplied from an air supply device 9 flows from one end of the housing pipe 3 into an upstream space 10 formed in the housing pipe 3. Such a configuration is useful when there is a limit to the installation space around the central axis L of the burner.

[0083] 20, the burner 1 may not form the upstream space 10 inside the housing pipe 3, but may use a housing 7 on the rear side of one end of the housing pipe 3 to form the upstream space 10 outside the housing pipe 3. In this case, the housing 7 and the secondary air flow path 8 may be communicated with each other, and part of the air A may be introduced as secondary air A2.

[0084] (Experimental example) A burner with the curved swirl blades shown in Figures 1 to 10 was fabricated. Figure 21 shows the appearance of the fabricated burner when an air supply device is attached. The burner shown in Figure 21 was fabricated as a burner capable of burning non-preheated standard air (oxygen concentration 21%) and ammonia gas (purity 99.999%). In addition, the burner shown in Figure 21 has a double-tube structure with the combustion tube tip and outer tube made of quartz glass pipe, making it possible to observe the flame of ammonia fuel from the side of the burner.

[0085] In this experimental example, a blower was used as the air supply device, and ammonia gas was supplied as the first fuel by a first fuel supply unit. The burner is designed so that the internal heating is hardly performed until each gas is ejected into the tubular space, and a gas flow containing ammonia gas and air is ejected from the inter-blade passage into the tubular space, forming a swirling flow. Ignition is performed by intermittent discharge from a spark plug or ignition electrode only at the time of ignition. After ignition, the discharge is stopped, but a continuous flame is obtained thereafter.

[0086] Ammonia gas (purity 99.999%) is supplied from a cylinder to the burner via a pressure regulator and mass flow meter. Because the mass flow meter used (Kofloc Corporation, Model 3810DSII, for air, maximum flow rate 100NL / min., needle valve included) was for air, the material of the internal packing was changed from fluororubber to butyl rubber and nitrile rubber to protect against corrosion by ammonia, and the flow rate was also calibrated for ammonia gas before use.

[0087] In addition, air (standard air, room temperature, normal pressure, oxygen concentration 21.0%, non-preheated) was supplied through a rectifying inlet pipe and an ultrasonic flowmeter (Aichi Tokei Denki Co., Ltd., TRX65D-C / 5P, diameter 65A, maximum measured flow rate 240m 3 / h), blower (Makita, UB1103, power supply single phase 100V, current 6.3A, air volume 0-4.1m 3 / min., stepless speed control, power consumption 600W, dust collector air volume 0~4.1m 3 / min., vacuum level 0-5.7kPa) and then supplied to the burner. The power supply to the blower was adjusted to 20-30V using a variac, so the actual power consumption was estimated to be around 24-54W.

[0088] Figure 22 shows the design drawing of a small combustion furnace 90 constructed for the combustion test of the burner described above. As shown in Figure 22, the dimensions of the combustion furnace body 91 are 450 mm in length and 200 mm square, and the dimensions of the chimney section 92 are 300 mm in length and 60 mm square. The insulating wall material of both furnaces is biodegradable ceramic fiber board (25 mm thick, refractory temperature 1100°C). A gas sampling port for measuring gas concentration using a gas concentration measuring instrument 93 is drilled in the chimney section 92 at a position determined based on JIS K0095. In addition, a ceramic honeycomb 94 is installed upstream of the chimney section to rectify the flow near the sampling port.

[0089] The burner shown in Fig. 21 was set at the bottom of a small combustion furnace so that an upward flame could be formed. The combustion test was performed as shown in Fig. 23 and Fig. 24. In this combustion test, the outlet flow path width of the inter-blade flow path was h = 2.36 mm, and the swirl number S = 1.9 (inflow swirl number S' = 0.56).

[0090] As shown in Figures 23 and 24, it was demonstrated that combustion using a tubular flame is possible. This confirmed that the above burner can be made smaller and can be operated even when ammonia, which is a type of flame-retardant fuel, is used as fuel.

[0091] As shown in Fig. 23, the burner was connected to the small combustion furnace 90 shown in Fig. 22, and a premixed gas of air (standard air, room temperature, normal pressure, oxygen concentration 21.0%) and fuel (100% ammonia, room temperature) at an air flow rate of 160 L / min was supplied to the tubular space through the passage between the blades, and the combustion exhaust gas components were measured. Note that the measurement was carried out by inserting the tip of a gas concentration measuring instrument 93 into the chimney 92 as shown in Fig. 22 and sucking in the combustion exhaust gas.

[0092] Figures 25 and 26 show the measurement results of the N concentration and NO2 concentration (O2 12% equivalent), respectively. The NO concentration and NO2 concentration are maximum at an equivalence ratio of 1.1. At equivalence ratios of 0.9 and 1.0, which are leaner fuel, extremely low NO concentration (180 ppm or less) and NO2 concentration are obtained. The combustion method used here is a method in which the fuel is completely burned in the combustion region up to the annular lid portion 51, and the combustion gas has low NOx (method <1> ) or a method of not completely burning the fuel in the combustion region up to the annular lid portion 51, and reducing the NOx in the combustion gas by the unburned ammonia component, thereby obtaining low NOx exhaust characteristics (method <2> ) are available, but whichever method is realized, low NOx characteristics of exhaust gas at the combustion furnace outlet can be obtained.The above results confirmed that by forming a well-ordered swirl flow, it is possible to realize an unprecedented ammonia-fired low NOx burner using only normal air and ammonia without preheating.

[0093] Furthermore, in a burner having a curved swirl vane, the angle of the swirl vane is changed to change the outlet flow passage width h of the inter-blade flow passage, and data on the swirl strength and maximum heat release amount are summarized in Table 1. In this disclosure, the supply calorific value of the supplied fuel is considered to be the heat release amount.

[0094] [Table 1]

[0095] The present invention is not limited to the above-described embodiments and experimental examples, and various modifications are possible within the scope of the gist thereof. Furthermore, the configurations shown in the above-described embodiments and experimental examples can be combined in any manner. Furthermore, the claims set forth in the scope of the claims as originally filed can be combined in any manner.

[0096] The features of the present invention are as follows. Section 1. a burner internal unit; a housing tube that houses the burner internal unit therein, A burner in which an upstream space to which air is supplied from an air supply device is formed upstream of the burner internal unit as viewed in the direction of the burner central axis, The burner internal unit comprises: a tubular space provided in the center of the unit; a combustion tube base portion having a bottom and a tubular shape, the combustion tube base portion being connected to one end of the tubular space; a plurality of swirl vanes for forming a swirl flow provided so as to surround the outer periphery of the tubular space; an annular plate member provided at the tip of the unit and fixing a side edge of each of the swirl vanes on the tip side of the unit; inter-blade flow passages formed between adjacent swirl vanes; an air inflow restriction portion for restricting the inflow of the air from a portion of each inter-blade passage extending from a midpoint of a side end surface on the upstream space side to the combustion tube base, The burner is an intermediate flow passage communicating the upstream space with the inter-blade flow passage is formed between the combustion tube base and the housing pipe, the combustion tube further includes a fuel supply unit including at least one of a first fuel supply unit capable of supplying a first fuel into the combustion tube base and a second fuel supply unit capable of supplying a second fuel to at least one selected from the inter-blade flow passage, the intermediate flow passage, the upstream space, and the tubular space, a gas flow passing through the inter-blade passage and ejected into the tubular space forms a swirling flow in the tubular space; Burner. Section 2. an air inlet for allowing the air supplied from the air supply device to flow into the upstream space is formed in a part of the peripheral wall of the housing pipe; Item 1. The burner according to item 1. Section 3. The air supplied from the air supply device is configured to flow from one end of the housing pipe into the upstream space. Item 1 or 2. The burner according to item 1 or 2. Section 4. a tubular combustion tube tip portion connected to the other end of the tubular space; Item 1 to Item 3: A burner according to any one of items 1 to 3. Section 5. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A secondary air flow path is formed between the tip of the combustion tube and the outer tube, a portion of the air introduced into the inter-blade passage can flow into the secondary air passage through a communication hole formed in the annular plate member; Item 1 to Item 4: A burner according to any one of items 1 to 4. Section 6. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A secondary air flow path is formed between the tip of the combustion tube and the outer tube, A part of the air supplied from the air supply device is directly supplied to the secondary air flow path. Item 6. The burner according to any one of items 1 to 5. Section 7. a housing that covers the housing tube; a cooling space to which a portion of the air from the air supply device is supplied is formed between the peripheral wall of the housing and the housing; Item 7. The burner according to any one of items 1 to 6. Section 8. an observation window for observing the flame formed inside the burner; Item 8. The burner according to any one of items 1 to 7. Section 9. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A fluid flow path is formed between the combustion tube tip and the outer tube, The fuel or reducing gas is configured to be directly supplied to the fluid flow path. Item 9. The burner according to any one of items 1 to 8. Section 10. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A fluid flow path is formed between the combustion tube tip and the outer tube, Ammonia is directly supplied to the fluid flow path, Ammonia-fueled Item 10. The burner according to any one of items 1 to 9. [Explanation of symbols]

[0097] 1 Burner 10 Upstream space 11 Intermediate flow path 2 Burner internal unit 20 tubular space 21 Combustion tube base 22 Swirl blades 23 Annular plate material 24 Blade passage 25 Air inflow restriction section 3. Containment tube 4 Fuel supply section 41 1st fuel supply section 42 2nd fuel supply section L Burner central axis 9 Air supply device A. Air A1 Primary air A2 Secondary air F1 No. 1 fuel F2 Second Fuel

Claims

1. a burner internal unit; a housing tube that houses the burner internal unit therein, A burner in which an upstream space to which air is supplied from an air supply device is formed upstream of the burner internal unit as viewed in the direction of the burner central axis, The burner internal unit comprises: a tubular space provided in the center of the unit; a combustion tube base portion having a bottom and a tubular shape, the combustion tube base portion being connected to one end of the tubular space; a plurality of swirl vanes for forming a swirl flow provided so as to surround the outer periphery of the tubular space; an annular plate member provided at the tip of the unit and fixing a side edge of each of the swirl vanes on the tip side of the unit; inter-blade flow passages formed between adjacent swirl vanes; an air inflow restriction portion for restricting the inflow of the air from a portion of each inter-blade passage extending from a midpoint of a side end surface on the upstream space side to the combustion tube base, The burner is an intermediate flow passage communicating the upstream space with the inter-blade flow passage is formed between the combustion tube base and the housing pipe, the combustion tube further includes a fuel supply unit including at least one of a first fuel supply unit capable of supplying a first fuel into the combustion tube base and a second fuel supply unit capable of supplying a second fuel to at least one selected from the inter-blade flow passage, the intermediate flow passage, the upstream space, and the tubular space, In each of the inter-blade flow passages, inner surfaces of the adjacent swirl vanes on the flow passage side define each of the inter-blade flow passages, a gas flow passing through the inter-blade passage and ejected into the tubular space forms a swirling flow in the tubular space; Burner.

2. an air inlet for allowing the air supplied from the air supply device to flow into the upstream space is formed in a part of the peripheral wall of the housing pipe; 2. The burner of claim 1.

3. The air supplied from the air supply device is configured to flow from one end of the housing pipe into the upstream space.

2. The burner of claim 1.

4. a tubular combustion tube tip portion connected to the other end of the tubular space; 2. The burner of claim 1.

5. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A secondary air flow path is formed between the tip of the combustion tube and the outer tube, a portion of the air introduced into the inter-blade passage can flow into the secondary air passage through a communication hole formed in the annular plate member; 2. The burner of claim 1.

6. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A secondary air flow path is formed between the tip of the combustion tube and the outer tube, A part of the air supplied from the air supply device is directly supplied to the secondary air flow path.

2. The burner of claim 1.

7. a housing that covers the housing tube; a cooling space to which a portion of the air from the air supply device is supplied is formed between the peripheral wall of the housing and the housing; 2. The burner of claim 1.

8. an observation window for observing the flame formed inside the burner; 2. The burner of claim 1.

9. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A fluid flow path is formed between the combustion tube tip and the outer tube, The fuel or reducing gas is configured to be directly supplied to the fluid flow path.

2. The burner of claim 1.

10. a tubular combustion tube tip portion connected to the other end of the tubular space, a tubular outer tube on the outer periphery of the tip of the combustion tube; A fluid flow path is formed between the combustion tube tip and the outer tube, Ammonia is directly supplied to the fluid flow path, Ammonia-fueled 2. The burner of claim 1.

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