Duct burner and gas turbine system

Abstract

This duct burner is disposed in an exhaust-gas flow path through which exhaust gas discharged from a gas turbine flows, and comprises: at least one nozzle for jetting gas fuel into the exhaust-gas flow path; and a flame stabilizer that includes a pair of plate members that are situated opposing each other sandwiching the nozzle and, heading downstream in the exhaust-gas flow path, separate from the center axis of the nozzle. The nozzle includes: at least one auxiliary hole configured to jet gas fuel along a flame-stabilizing surface of the plate member downstream in the exhaust-gas flow path; and at least one main hole that is diametrically larger than the auxiliary hole and is configured to jet gas fuel inclined more to the nozzle center-axis side than the auxiliary hole.

Description

[Technical Field]

[0001] This invention relates to a channel burner and a gas turbine system equipped with the channel burner. This application claims priority based on Japanese Patent Application No. 2023-137752 filed with the Japanese Patent Office on August 28, 2023, the contents of which are incorporated herein by reference. [Previous Technology]

[0002] For example, as disclosed in Non-Patent Document 1, in a gas turbine cogeneration system comprising a gas turbine and a waste heat recovery boiler, a channel burner is installed upstream of the waste heat recovery boiler to increase the heat recovery capacity. The channel burner injects fuel into the exhaust gas discharged from the gas turbine, utilizing the oxygen contained in the exhaust gas for combustion heating. [Prior Art Documents] [Non-Patent Documents]

[0003] [Non-Patent Document 1] IHI Technical Report Vol.49 No.2 (2009-6) P103-P107 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] However, when the oxygen concentration in the exhaust is low, it is not easy to make the channel burner burn stably.

[0006] This invention was made in view of the above-mentioned problems, and provides a channel burner capable of stable combustion. [Technical Means for Solving the Problem]

[0007] To achieve the above objective, the channel burner of the present invention is disposed in an exhaust flow path through which exhaust gas discharged from a gas turbine flows. The channel burner includes: at least one nozzle that sprays gaseous fuel into the exhaust flow path; and a flame retainer comprising a pair of plate-like members located on opposite sides of the nozzle and moving away from the central axis of the nozzle toward the downstream side of the exhaust flow path. The nozzle includes: at least one secondary orifice configured to spray the gaseous fuel along the flame retainer surface of the plate-like members on the downstream side of the exhaust flow path; and at least one main orifice with a diameter larger than the secondary orifice and configured to spray the gaseous fuel obliquely toward the central axis of the nozzle, closer to the secondary orifice than to the secondary orifice. [Effects of the Invention]

[0008] The channel burner according to the present invention can achieve stable combustion.

Implementation Method

[0010] Hereinafter, a channel burner according to an embodiment of the present invention will be described with reference to the drawings. This embodiment is an example of the present invention and is not intended to limit the disclosure; any modifications may be made within the scope of the technical concept of the present invention.

[0011] <Gas Turbine> Figure 1 is a schematic diagram showing the structure of a gas turbine system 100 with a channel burner 1 in several embodiments. As shown in Figure 1, the gas turbine system 100 includes: a gas turbine 110, an exhaust flow path 120 through which exhaust gas G discharged from the gas turbine 110 flows, a heat recovery boiler 130 disposed in the exhaust flow path 120, and a channel burner 1 in several embodiments.

[0012] The gas turbine 110 includes: a compressor 112, a combustor 114, and a turbine 116. The compressor 112 compresses externally supplied air A1 to produce compressed air A2. The combustor 114 injects fuel A3 into the compressed air A2 produced by the compressor 112 to burn it, thereby producing combustion gas A4. Fuel A3 is not particularly limited, but is hydrogen in this embodiment. In several embodiments, fuel A3 may be, for example, a hydrocarbon gas such as LPG or LNG.

[0013] The turbine 116 is driven to rotate by the passage of combustion gas A4 generated by the burner 114, converting the thermal energy of the combustion gas A4 into rotational energy. The turbine 116 is connected to the compressor 112 via a rotating shaft 113, transmitting the rotational energy to the compressor 112. The compressor 112 is driven using the rotational energy of the turbine 116. In the embodiment illustrated in FIG. 1, the gas turbine system 100 further includes a generator 140 connected to the rotating shaft 113. The generator 140 uses the rotational energy of the turbine 116 to generate electricity.

[0014] The exhaust flow path 120 is defined by the inner wall surface 124 of the cylindrical channel 122 (see Figure 2). The exhaust heat recovery boiler 130 uses the thermal energy of the exhaust gas G to heat the supply water to generate steam. The supply target of the exhaust gas G through the exhaust heat recovery boiler 130 is not particularly limited, but may be, for example, a CO2 absorption tower that absorbs CO2 from the exhaust gas G into the absorbent.

[0015] <Channel Burner> (Construction) The channel burner 1 is disposed upstream of the exhaust flow path 120, which is further upstream than the exhaust heat recovery boiler 130. Figure 2 is a schematic diagram showing the construction of a channel burner 1 in one embodiment, and is a view of the channel burner 1 from the downstream side of the exhaust flow path 120 (front view).

[0016] In one embodiment, as shown in FIG2, the channel burner 1 includes a plurality of fuel supply pipes 2 extending along the left-right direction D1 in the exhaust flow path 120. The plurality of fuel supply pipes 2 are arranged side by side with gaps between them along the up-down direction D2. Each of the plurality of fuel supply pipes 2 has a cylindrical shape, and gaseous fuel F supplied by a supply source (not shown) flows inside. The gaseous fuel F is not particularly limited, but is hydrogen in this case. The gaseous fuel F may also be a hydrocarbon gas such as LPG or LNG.

[0017] The channel burner 1 includes: a nozzle 4 connected to the fuel supply pipe 2 and spraying gaseous fuel F into the exhaust flow path 120; and a flame retainer 6 having a pair of plate-shaped members 8A and 8B, which are located on opposite sides of each other across the nozzle 4. In one embodiment, as shown in FIG2, a plurality of nozzles 4 are arranged side by side along the left-right direction D1 in a fuel supply pipe 2 (forming a manifold).

[0018] A pair of plate-shaped members 8A and 8B are arranged side by side along the vertical direction D2, comprising: an upper plate-shaped member 8A and a lower plate-shaped member 8B located below the upper plate-shaped member 8A. The upper plate-shaped member 8A and the lower plate-shaped member 8B are connected to a common nozzle 4. When viewed from the front, the upper plate-shaped member 8A and the lower plate-shaped member 8B are configured such that at least a portion of each other overlaps in the horizontal direction D1.

[0019] Furthermore, in the configuration illustrated in Figure 2, a plurality of nozzles 4 are arranged side-by-side along the left-right direction D1 on a fuel supply pipe 2, but the present invention is not limited to this configuration. The channel burner 1 may also include: a fuel supply pipe 2 extending along the vertical direction D2, and a plurality of nozzles 4 arranged side-by-side along the vertical direction D2 on the fuel supply pipe 2. In this case, a pair of plate-shaped members 8A and 8B are arranged on opposite sides of each other in the left-right direction D1, separated by the nozzles 4.

[0020] In one embodiment, as shown in FIG2, the channel burner 1 further includes an ignition device 30 for igniting gaseous fuel F. The ignition device 30 is provided in the channel 122, located downstream of the exhaust flow path 120, further than the nozzle 4. The ignition device 30 can be configured to ignite the gaseous fuel F, for example, a pre-ignition method using a flame generated by a small burner to ignite the gaseous fuel F can be used, or a direct ignition method using a spark plug to ignite the gaseous fuel F can be used. The ignition device 30 can also be provided for each fuel supply pipe 2. Among the plurality of nozzles 4 provided in a fuel supply pipe 2, the nozzle 4 closest to the ignition device 30 is the ignition nozzle 20 (4). The plurality of nozzles 4 provided in a fuel supply pipe 2 includes: a left nozzle 40 (4) and a right nozzle 42 (4) adjacent to the right of the left nozzle 40. The structure of the ignition nozzle 20, the left nozzle 40, and the right nozzle 42 will be described later.

[0021] Figure 3 is a side cross-sectional view of a nozzle 4 according to one embodiment. As shown in Figure 3, the nozzle 4 includes a main orifice 10 and a secondary orifice 12. The secondary orifice 12 is configured to eject gaseous fuel F along the downstream side of the exhaust flow path 120 of the upper plate-shaped member 8A or the lower plate-shaped member 8B on the heat-insulating surface 14. The main orifice 10 has a larger diameter than the secondary orifice 12. The main orifice 10 is configured to eject gaseous fuel F at an angle closer to the central axis O of the nozzle 4 than the secondary orifice 12.

[0022] A specific structural example of the main hole 10 and the secondary hole 12 in one embodiment will be described. The main hole 10 and the secondary hole 12 each extend in a straight line. The angle formed by the virtual first straight line L1 extending in the ejection direction of the main hole 10 and the central axis O of the nozzle 4 is the main hole ejection angle θ1. The angle formed by the virtual second straight line L2 extending in the ejection direction of the secondary hole 12 and the central axis O of the nozzle 4 is the secondary hole ejection angle θ2. The main hole ejection angle θ1 is 20 degrees or more and less than 40 degrees. The secondary hole ejection angle θ2 is 40 degrees or more and less than 50 degrees.

[0023] As shown in Figure 3, the upper plate-shaped member 8A and the lower plate-shaped member 8B each move away from the central axis O of the nozzle 4 as they move downstream of the exhaust flow path 120. The upper plate-shaped member 8A and the lower plate-shaped member 8B are each linearly symmetrical about the central axis O of the nozzle. The upper plate-shaped member 8A and the lower plate-shaped member 8B are each configured such that the angle θ3 of the flame-protecting surface 14 with respect to the central axis O of the nozzle 4 is 40 degrees or more and 50 degrees or less. In one embodiment, the angle θ3 of the flame-protecting surface 14 is 45 degrees. The angle θ3 of the flame-protecting surface 14 is the same as the ejection angle θ2 of the secondary orifice.

[0024] The upper plate-shaped member 8A and the lower plate-shaped member 8B each have a plurality of through holes 18 extending from the heat-insulating surface 14 to the surface 16 opposite to the heat-insulating surface 14. The ratio of the area of ​​the plurality of through holes 18 to the area of ​​the heat-insulating surface 14, which includes the area of ​​the plurality of through holes 18, is defined as the opening ratio, which is more than 20% and less than 50%. Furthermore, the number of through holes 18 is not particularly limited, and may be one or more.

[0025] Figure 4 is a schematic diagram showing the structure of a nozzle 4 in one embodiment, and is a view of the nozzle 4 from the downstream side of the exhaust flow path 120 (front view). In one embodiment, as shown in Figure 4, four main holes 10 and four secondary holes 12 are formed in the nozzle 4. The four main holes 10 are symmetrically arranged around the central axis O of the nozzle 4, separated by the central axis O of the nozzle. The four secondary holes 12 are symmetrically arranged around the central axis O of the nozzle 4, separated by the central axis O of the nozzle. The four main holes 10 and the four secondary holes 12 are each equally and alternately arranged around the central axis O of the nozzle 4. That is, the spacing angle α around the central axis O of the nozzle 4 is 45 degrees. In the front view, the center position 10a of the opening of the main hole 10 and the center position 12a of the opening of the secondary hole 12 are equidistant from the central axis O of the nozzle 4. Furthermore, the cross-sectional shape of the main holes 10 and the secondary holes 12 is circular.

[0026] Figure 5 is a schematic diagram showing the structure of an ignition nozzle 20 in one embodiment. As shown in Figure 5, the ignition nozzle 20 has a small-diameter orifice 21, which is configured to allow gaseous fuel F to be ejected from the side closer to the central axis O of the nozzle 4 than the four main orifices 10 and the four secondary orifices 12. The small-diameter orifice 21 has a smaller diameter than the four secondary orifices 12. In the embodiment shown in Figure 5, the small-diameter orifice 21 extends in a straight line along the central axis O of the nozzle 4. The small-diameter orifice 21 is located inside the radial direction of the nozzle 4 than the four main orifices 10 and the four secondary orifices 12. The small-diameter orifice 21 is formed on the front end face 23 of the ignition nozzle 20. The main orifices 10 and the secondary orifices 12 are each formed on an extension surface 27 extending from the front end face 23 of the ignition nozzle 20 toward the side face 25. In several embodiments, when the angle formed by the virtual straight line extending in the ejection direction of the small-diameter orifice 21 and the central axis O of the nozzle 4 is defined as the small-diameter orifice ejection angle, this small-diameter orifice ejection angle will be smaller than both the main orifice ejection angle θ1 and the secondary orifice ejection angle θ2. Furthermore, in the nozzle 4 illustrated in Figure 3, a main orifice 10 and a secondary orifice 12 are also formed on the extending surface.

[0027] Figure 6 is a schematic diagram showing the structure of the left nozzle 40 (4) and the right nozzle 42 (4) in one embodiment. As shown in Figure 6, when viewing the channel burner 1 from the downstream side of the exhaust flow path 120, the angular position θ of the virtual line L3 extending upward from the central axis O of the nozzle 4 is defined as 0 degrees. This angular position θ increases as the virtual line L3 rotates clockwise around the central axis O of the nozzle 4, and the angular position θ when the virtual line L3 rotates one revolution is defined as 360 degrees.

[0028] In the configuration illustrated in Figure 6, the left nozzle 40 and the right nozzle 42 each contain: an upper secondary hole 44 (12) with an angle position θ between 0 degrees and 10 degrees or between 350 degrees and 360 degrees, and a lower secondary hole 46 (12) with an angle position θ between 170 degrees and 190 degrees. The left nozzle 40 contains a right secondary hole 48 (12) with an angle position θ between 80 degrees and 100 degrees. The right nozzle 42 contains a left secondary hole 50 (12) with an angle position θ between 260 degrees and 280 degrees.

[0029] Figure 7 is a diagram that schematically illustrates the structure of the nozzle 4 in several embodiments. In the embodiment illustrated in Figure 7, the nozzle 4, in addition to the main hole 10 and the secondary hole 12, also includes a second secondary hole 54. The second secondary hole 54 includes: a second secondary hole 54A (54) on the right side with an angle position θ between 80 and 100 degrees, and a second secondary hole 54B (54) on the left side with an angle position θ between 260 and 280 degrees. The second secondary hole 54 is configured to spray gaseous fuel F at a spray angle of 50 to 90 degrees relative to the central axis O of the nozzle 4. That is, in the left-right direction D1 of the nozzle 4, there is no pair of plate-shaped members 8A and 8B, and the second secondary hole 54 is not configured to spray gaseous fuel F along the flame-retardant surface 14, but rather to prioritize improving the flame-retardant effect. The spray angle of the second secondary hole 54 is larger than the spray angle θ2 of the secondary hole. The second auxiliary hole 54 can have the same diameter as auxiliary hole 12, or it can have a different diameter.

[0030] According to the configuration illustrated in Figure 7, the ejection angle of the second auxiliary orifice 54 is larger than that of the right auxiliary orifice 48 and the left auxiliary orifice 50 illustrated in Figure 6. That is, the gaseous fuel F ejected from the second auxiliary orifice 54 can reach the adjacent nozzle 4 with a shorter distance compared to the gaseous fuel F ejected from the right auxiliary orifice 48 and the left auxiliary orifice 50. Therefore, the nozzle 4 equipped with the second auxiliary orifice 54 can quickly ignite the nozzle 4 adjacent to it.

[0031] (Function, Effect) The function and effect of the channel burner 1 in one embodiment will be explained. Figure 8 is a graph showing whether the channel burner 1 in one embodiment performs stable combustion. It is a graph with the oxygen concentration of exhaust gas G on the horizontal axis and the temperature of exhaust gas G on the vertical axis. Stable combustion of the channel burner 1 refers to the state in which the channel burner 1 forms a flame through the combustion of gaseous fuel F. The oxygen concentration of exhaust gas G is the concentration of oxygen contained in the exhaust gas G flowing into the channel burner 1. The temperature of exhaust gas G is the temperature of the exhaust gas G flowing into the channel burner 1.

[0032] In Figure 8, the ● indicates that the channel burner 1 of one embodiment is performing stable combustion, the ○ indicates that the channel burner with a conventional nozzle is performing stable combustion, and the × indicates that the channel burner with a conventional nozzle is not performing stable combustion. Conventional nozzles are nozzles that only have a plurality of main holes with the same ejection angle, and do not have secondary holes. Furthermore, channel burners with conventional nozzles do not have a flame-holding mechanism at the nozzle; the nozzle base is in a blown-off state, and the flame is held near the flame-holding mechanism of the channel burner.

[0033] Whether stable combustion occurs in the channel burner 1 depends mainly on the oxygen concentration and temperature of the exhaust gas G. If the oxygen concentration of the exhaust gas G is low, the combustion in the channel burner 1 will be unstable. Similarly, if the temperature of the exhaust gas G is low, the combustion in the channel burner 1 will be unstable. As shown in Figure 8, in one embodiment of the channel burner 1, if the oxygen concentration of the exhaust gas G is above 7%, stable combustion can occur even if the temperature of the exhaust gas G is 300 degrees Celsius. On the other hand, in conventional channel burners 1, if the oxygen concentration of the exhaust gas G is 8% or 11%, stable combustion cannot occur if the temperature of the exhaust gas G is 300 degrees Celsius. In conventional channel burners 1, in order to achieve stable combustion when the oxygen concentration of the exhaust gas G is 8% or 11%, it is necessary to make the temperature of the exhaust gas G higher than 300 degrees Celsius. As shown in Figure 8, the stable combustion boundary B1 of one embodiment of the channel burner 1, in the low oxygen region (below 14%), is at a lower temperature than the stable combustion boundary B2 of conventional channel burners. Therefore, the channel burner 1 of one embodiment can expand the conditions for stable combustion compared to the conventional channel burner 1.

[0034] In the channel burner 1, the exhaust gas G contains a low oxygen concentration, making stable combustion difficult. According to one embodiment, the secondary orifice 12 ejects gaseous fuel F along the flame-retardant surface 14, thus promoting mixing of the gaseous fuel F with the exhaust gas G in the vicinity C1 (see Figure 3) where the gaseous fuel F is ejected from the nozzle 4, thereby suppressing flame swaying and enhancing flame retention. Furthermore, the main orifice 10 ejects gaseous fuel F at an angle further towards the nozzle's central axis O than the secondary orifice 12, thus promoting slow combustion caused by elongated flame formation. Additionally, the generation of nitrogen oxides (NOx) can be suppressed. Therefore, stable combustion can be achieved in the channel burner 1.

[0035] According to one embodiment, the ejection angle θ1 (the elevation angle relative to the central axis O of the nozzle 4) of the main orifice 10 is made to be 40 degrees or less, thereby promoting slow combustion caused by elongated flame formation. On the other hand, if the ejection angle θ1 of the main orifice 10 is less than 20 degrees, excessive elongated flame formation will occur, which may affect the heat absorption characteristics of the exhaust heat recovery boiler 130 that supplies the exhaust gas G heated by the channel burner 1. Furthermore, if the ejection angle θ2 of the secondary orifice 12 is made to be 40 degrees or more, the gaseous fuel F will burn from the root of the front end of the nozzle 4, and the nozzle 4 can have a higher flame retention effect. Furthermore, if the ejection angle θ2 of the secondary orifice 12 is made to be 50 degrees or more, the flame formed by the combustion of the gaseous fuel F ejected from the secondary orifice 12 will come into contact with the flame retention surface 14, which may reduce the durability of the flame retainer 6. On the other hand, if the ejection angle θ2 of the secondary orifice 12 is less than 40 degrees, the flame from the secondary orifice will be moved away from the flame retainer 6, resulting in a reduction in the flame retention effect. Therefore, the ejection angle θ1 of the main orifice 10 is set to be more than 20 degrees and less than 40 degrees, and the ejection angle θ2 of the secondary orifice 12 is set to be more than 40 degrees and less than 50 degrees, thereby achieving stable combustion in the channel burner 1. Furthermore, the angle θ3 of the flame retaining surface 14 is typically set to 45 degrees. Therefore, the channel burner 1 is configured such that the ejection angle θ2 of the secondary orifice 12 is more than 40 degrees and less than 50 degrees, thereby suppressing the reduction in the durability of the flame retainer 6 and ensuring a certain flame retention effect.

[0036] According to one embodiment, through holes 18 are formed in the upper plate-shaped member 8A and the lower plate-shaped member 8B, so the amount of exhaust gas G supplied to the vicinity of the gaseous fuel F ejected from the nozzle 4 can be adjusted. If the opening ratio is less than 20%, the amount of exhaust gas G passing through the through holes 18 is less, and the amount of exhaust gas G necessary for cooling the flame retainer 6 will be insufficient, which may lead to overheating of the flame retainer 6. If the opening ratio is greater than 50%, the flame-retaining effect may be reduced depending on the type of gaseous fuel F. Therefore, according to one embodiment, the opening ratio is more than 20% and less than 50%, so the generation of NOx can be better suppressed.

[0037] According to one embodiment, a small-diameter orifice 21 is formed in the ignition nozzle 20, which allows the gaseous fuel F to be ejected from the side closer to the central axis O of the nozzle 4 than the four main orifices 10 and the four secondary orifices 12. Therefore, when the channel burner 1 is started, the gaseous fuel F will ignite, causing the combustion zone C2 (see Figure 5) to expand. This improves the ignition performance of the channel burner 1.

[0038] According to one embodiment, the ignition nozzle 20 is disposed among the plurality of nozzles 4 that is closest to the ignition device 30. Therefore, it is not necessary for all or most of the plurality of nozzles 4 to be ignition nozzles 20 to improve the ignition performance of the channel burner 1. Furthermore, the channel burner 1 may also have a plurality of ignition nozzles 20. The ignition nozzle 20 may be any nozzle other than the one closest to the ignition device 30 among the plurality of nozzles 4.

[0039] According to one embodiment, four main holes 10 and four secondary holes 12 are arranged alternately side-by-side around the central axis O of the nozzle 4. Therefore, gaseous fuel F is ejected uniformly and without bias from the four main holes 10 relative to the central axis O of the nozzle 4, and is also ejected uniformly and without bias from the four secondary holes 12 relative to the central axis O of the nozzle 4. This allows for continuous and uninterrupted slow combustion caused by elongated flame formation.

[0040] Exhaust gas G is supplied to the region C1 near the gaseous fuel F ejected from the nozzle 4 through through holes 18 formed in the upper plate-shaped member 8A and the lower plate-shaped member 8B, respectively. That is, exhaust gas G is supplied from above or below the nozzle 4. According to one embodiment, the left nozzle 40 and the right nozzle 42 each include an upper secondary hole 44 and a lower secondary hole 46, so that the gaseous fuel F ejected from the upper secondary hole 44 and the lower secondary hole 46 can be rapidly mixed with exhaust gas G.

[0041] According to one embodiment, the left nozzle 40 has a right auxiliary orifice 48, and the right nozzle 42 has a left auxiliary orifice 50. Therefore, the left nozzle 40 can be used to ignite the right nozzle 42, or the right nozzle 42 can be used to ignite the left nozzle 40. Furthermore, if the diameter of the right auxiliary orifice 48 or the left auxiliary orifice 50 is made large enough, for example, to be the same as the main orifice 10, the flames of the left nozzle 40 and the right nozzle 42 will come into contact with each other, causing the temperature to rise and potentially generating NOx. Therefore, the auxiliary orifice 12 is preferably opened in the left-right direction D1.

[0042] In one embodiment, the gaseous fuel F is hydrogen, but the present invention is not limited to this embodiment. In another embodiment, the gaseous fuel F is LPG. Figure 9 is a graph showing whether the channel burner 1 of the other embodiment is performing stable combustion, and is a graph with the oxygen concentration of the exhaust gas G on the horizontal axis and the temperature of the exhaust gas G on the vertical axis.

[0043] In Figure 9, ● indicates that the channel burner 1 of another embodiment is performing stable combustion, and + indicates that the channel burner 1 of another embodiment is performing stable combustion. Similarly, 〇 indicates that the channel burner equipped with a conventional nozzle is performing stable combustion, and × indicates that the channel burner equipped with a conventional nozzle is not performing stable combustion.

[0044] As shown in Figure 9, in another embodiment of the channel burner 1, if the oxygen concentration of the exhaust gas G is 12%, stable combustion can be achieved even if the temperature of the exhaust gas G is 400 degrees Celsius. On the other hand, in a conventional channel burner 1, if the oxygen concentration of the exhaust gas G is 12% and the temperature of the exhaust gas G is 400 degrees Celsius, stable combustion cannot be achieved. In a conventional channel burner 1, in order to achieve stable combustion when the oxygen concentration of the exhaust gas G is 10%, it is necessary to make the temperature of the exhaust gas G higher than 400 degrees Celsius (approximately 650 degrees Celsius). As shown in Figure 9, the stable combustion boundary B3 of the channel burner 1 in the other embodiment, in the low oxygen region (below 14%), is at a lower temperature than the stable combustion boundary B4 of the conventional channel burner. Therefore, the channel burner 1 in the other embodiment expands the conditions for stable combustion compared to the conventional channel burner 1.

[0045] The contents recorded in the above-mentioned embodiments can be understood as follows, for example.

[0046] [1] The channel burner (1) of the present invention is disposed in an exhaust flow path (120) through which exhaust gas (G) discharged from a gas turbine (110) flows. The channel burner includes: at least one nozzle (4) that sprays gaseous fuel (F) into the exhaust flow path; and a flame retainer (6) that includes a pair of plate members (8A, 8B) located on opposite sides of each other across the aforementioned nozzle and moving away from the central axis (O) of the aforementioned nozzle as it moves toward the downstream side of the aforementioned exhaust flow path. The aforementioned nozzle includes: at least one secondary orifice (12) configured to spray the aforementioned gaseous fuel along the flame retainer surface (14) of the aforementioned plate member on the downstream side of the aforementioned exhaust flow path; and at least one main orifice (10) having a diameter larger than the aforementioned secondary orifice and configured to spray the aforementioned gaseous fuel at an angle toward the central axis side of the aforementioned nozzle, which is closer to the aforementioned nozzle than the aforementioned secondary orifice.

[0047] In a channel burner, the oxygen concentration in the exhaust gas is low, making stable combustion difficult. According to the structure described above [1], the secondary orifice sprays gaseous fuel along the flame-retardant surface, thus promoting the mixing of gaseous fuel and exhaust gas near the nozzle, and suppressing flame swaying to enhance flame retention. Furthermore, the main orifice sprays gaseous fuel at an angle further towards the central axis of the nozzle than the secondary orifice, thus promoting slow combustion caused by elongated flame formation (and suppressing the generation of nitrogen oxides). Therefore, stable combustion can be achieved in the channel burner.

[0048] [2] In several embodiments, in the structure described above[1], the aforementioned main hole is configured such that the ejection angle (θ1) relative to the central axis of the aforementioned nozzle is 20 degrees or more and less than 40 degrees, the aforementioned secondary hole is configured such that the ejection angle (θ2) relative to the central axis of the aforementioned nozzle is 40 degrees or more and less than 50 degrees, and the angle (θ3) of the aforementioned heat-preserving surface relative to the central axis of the aforementioned nozzle is 40 degrees or more and less than 50 degrees.

[0049] According to the structure described above [2], the ejection angle of the main orifice (the elevation angle relative to the central axis of the nozzle) is less than 40 degrees, thereby promoting slow combustion caused by elongated flame. On the other hand, if the ejection angle of the main orifice is less than 20 degrees, excessive elongated flame will occur, which may affect the heat absorption characteristics of the waste heat boiler that supplies the exhaust gas heated by the channel burner. Furthermore, the ejection angle of the secondary orifice is 40 degrees or more, thereby enabling the nozzle to have a higher flame retention effect. Therefore, by making the ejection angle of the main orifice between 20 and 40 degrees and the ejection angle of the secondary orifice between 40 and 50 degrees, stable combustion of the channel burner can be achieved.

[0050] [3] In several embodiments, in the structure described in [1] or [2] above, at least one through hole (18) is formed in the aforementioned plate-shaped member, extending from the aforementioned heat-preserving surface to the surface (16) opposite to the aforementioned heat-preserving surface.

[0051] According to the structure described above[3], the amount of exhaust gas supplied to the vicinity of the nozzle where the gaseous fuel is ejected can be adjusted.

[0052] [4] In several embodiments, in the structure described above[3], a plurality of the aforementioned through holes are formed in the aforementioned plate-shaped member, and the ratio of the area of ​​the plurality of the aforementioned through holes to the area of ​​the aforementioned heat-insulating surface, if defined as the opening ratio, is 20% or more and 50% or less.

[0053] If the opening ratio is less than 20%, the amount of exhaust through the through hole is less, and the amount of exhaust required for the cooling of the heat preservation device will be insufficient, which may cause the heat preservation device to overheat. If the opening ratio is greater than 50%, the heat preservation effect may be reduced depending on the type of gaseous fuel. According to the structure described above [4], the opening ratio is more than 20% and less than 50%, so the generation of nitrogen oxides can be better suppressed.

[0054] [5] In several embodiments, in any of the above-described [1] to [4], the aforementioned at least one main hole includes a plurality of the aforementioned main holes arranged side by side around the central axis of the aforementioned nozzle, the aforementioned at least one secondary hole includes a plurality of the aforementioned secondary holes arranged side by side around the central axis of the aforementioned nozzle, the aforementioned nozzle includes an ignition nozzle (20) having a small-diameter hole (21) with a diameter smaller than the aforementioned secondary holes, and configured to eject the aforementioned gaseous fuel from the side of the central axis of the aforementioned nozzle that is closer to the plurality of the aforementioned main holes and the plurality of the aforementioned secondary holes.

[0055] According to the structure described above [5], the small-diameter orifice allows the gaseous fuel to be ejected from the central axis side of the nozzle, which is closer to the nozzle than the plurality of main orifices and the plurality of secondary orifices. Therefore, when the channel burner is started, the gaseous fuel will be ignited and the combustion area will be expanded. Thus, the ignition performance of the channel burner can be improved.

[0056] [6] In several embodiments, in the structure described above[5], an ignition device (30) is further provided, which is disposed in a channel (122) having an inner wall surface (124) that defines the aforementioned exhaust flow path, the aforementioned at least one nozzle comprising a plurality of the aforementioned nozzles, and the aforementioned nozzle disposed closest to the aforementioned ignition device among the plurality of the aforementioned nozzles being the aforementioned ignition nozzle.

[0057] According to the structure described above[6], the ignition performance of the channel burner can be improved without having all or most of the plurality of nozzles become ignition nozzles.

[0058] [7] In several embodiments, in any of the above-described [1] to [6], the aforementioned at least one nozzle contains a plurality of the aforementioned nozzles arranged side by side along the left-right direction (D1), and the aforementioned pair of plate-shaped members are arranged side by side along the up-down direction (D2).

[0059] According to the construction described above [7], a channel burner can be provided in which a plurality of nozzles are arranged side by side in the left-right direction and a pair of plate-shaped members are arranged side by side in the up-down direction.

[0060] [8] In several embodiments, in the structure described above[7], the aforementioned at least one main hole contains a plurality of the aforementioned main holes, the aforementioned at least one secondary hole contains a plurality of the aforementioned secondary holes, and the plurality of the aforementioned main holes and the plurality of the aforementioned secondary holes are arranged alternately side by side around the central axis of the aforementioned nozzle.

[0061] According to the structure described above [8], the gaseous fuel is ejected uniformly and without deviation from the central axis of the nozzle from a plurality of main holes, and equally and without deviation from the central axis of the nozzle from a plurality of secondary holes. Therefore, slow combustion caused by long strip flaming can be sustained without delay.

[0062] [9] In several embodiments, in the structure described above[8], the plurality of the aforementioned nozzles include: a left nozzle (40) and a right nozzle (42) adjacent to the right of the aforementioned left nozzle. When viewing the aforementioned channel burner from the downstream side of the aforementioned exhaust flow path, the angle position (θ) of the virtual line (L3) extending upward from the central axis of the aforementioned nozzle is defined as 0 degrees. The aforementioned angle position increases as the aforementioned nozzle rotates clockwise around the central axis of the aforementioned nozzle. When the aforementioned angle position when the aforementioned virtual line rotates one revolution is defined as 360 degrees, the aforementioned left nozzle and the aforementioned right nozzle each include: an upper secondary hole (44), which is one of the plurality of the aforementioned secondary holes, and the aforementioned angle position is between 0 degrees and 10 degrees or between 350 degrees and 360 degrees; and a lower secondary hole (46), which is one of the plurality of the aforementioned secondary holes, and the aforementioned angle position is between 170 degrees and 190 degrees.

[0063] Exhaust gas is supplied to the vicinity of the gaseous fuel ejected from the nozzle through through holes formed in a pair of plate-shaped members arranged side by side in the vertical direction. That is, exhaust gas is supplied from above or below the nozzle. According to the structure described above [9], the left nozzle and the right nozzle each include an upper secondary hole and a lower secondary hole, so that the gaseous fuel ejected from the upper secondary hole and the lower secondary hole can be rapidly mixed with the exhaust gas.

[0064]

[10] In several embodiments, in the structure described above [9], the aforementioned left nozzle contains a right auxiliary hole, which is one of the plurality of the aforementioned auxiliary holes, and the aforementioned angle position is between 80 degrees and 100 degrees. The aforementioned right nozzle contains a left auxiliary hole, which is one of the plurality of the aforementioned auxiliary holes, and the aforementioned angle position is between 260 degrees and 280 degrees.

[0065] According to the structure described above

[10] , the left nozzle can be used to ignite the right nozzle, or the right nozzle can be used to ignite the left nozzle.

[0066]

[11] In several embodiments, in the structure described above [9], the aforementioned nozzle further includes a second auxiliary hole, which is configured to spray the aforementioned gaseous fuel at an angle of 50 degrees to 90 degrees relative to the central axis of the aforementioned nozzle, wherein the angle of the aforementioned second auxiliary hole is between 80 degrees and 100 degrees, or between 260 degrees and 280 degrees.

[0067] According to the structure described above

[11] , the second auxiliary hole has a larger ejection angle compared to the right auxiliary hole or the left auxiliary hole described above

[10] . Therefore, a nozzle equipped with a second auxiliary hole can quickly ignite the nozzle adjacent to it.

[0068]

[12] In several embodiments, in any of the structures described in [1] to

[11] above, the aforementioned gaseous fuel is hydrogen or a hydrocarbon gas.

[0069] According to the structure described above

[12] , a channel burner suitable for hydrogen or hydrocarbon gases can be stably burned.

[0070]

[13] The gas turbine system of the present invention comprises: a gas turbine for use with hydrogen as fuel, and a channel burner as described in any of [1] to

[12] above.

[0071] Based on the construction described above

[13] , a gas turbine system with a channel burner for stable combustion can be provided. [Simplified Explanation of the Diagram]

[0009] [Figure 1] A schematic diagram showing the structure of a gas turbine system with a channel burner in one embodiment. [Figure 2] A schematic diagram showing the structure of a nozzle in one embodiment. [Figure 3] A side sectional view of a nozzle in one embodiment (view with arrow AA in Figure 4). [Figure 4] A schematic diagram showing the structure of a nozzle in one embodiment. [Figure 5] A schematic diagram showing the structure of an ignition nozzle in one embodiment. [Figure 6] A schematic diagram showing the structure of the left and right nozzles in one embodiment. [Figure 7] A schematic diagram showing the structure of nozzles in several embodiments. [Figure 8] A diagram showing whether the channel burner in one embodiment performs stable combustion. [Figure 9] A diagram showing whether the channel burner in another embodiment performs stable combustion.

Claims

1. A channel burner disposed in an exhaust flow path through which exhaust gas from a gas turbine flows, the channel burner comprising: at least one nozzle that sprays gaseous fuel into the exhaust flow path; and a flame retainer comprising a pair of plate-like members located on opposite sides of the nozzle and moving away from the central axis of the nozzle toward the downstream side of the exhaust flow path, the nozzle comprising: at least one secondary orifice configured to spray the gaseous fuel along the flame retainer surface of the plate-like members on the downstream side of the exhaust flow path; and at least one main orifice having a diameter larger than the secondary orifice and configured to spray the gaseous fuel obliquely toward the central axis of the nozzle, beyond the secondary orifice.

2. The channel burner as described in claim 1, wherein, The aforementioned main orifice is configured with a spray angle of 20 degrees or more and less than 40 degrees relative to the central axis of the aforementioned nozzle. The aforementioned secondary orifice is configured with a spray angle of 40 degrees or more and less than 50 degrees relative to the central axis of the aforementioned nozzle. The aforementioned heat-insulating surface is configured with an angle of 40 degrees or more and less than 50 degrees relative to the central axis of the aforementioned nozzle.

3. The channel burner as described in claim 1 or 2, wherein, The aforementioned plate-shaped member has at least one through hole extending from the aforementioned heat-preserving surface to the surface opposite to the aforementioned heat-preserving surface.

4. The channel burner as described in claim 3, wherein, The aforementioned plate-shaped member has a plurality of the aforementioned through holes. The ratio of the area of ​​the plurality of the aforementioned through holes to the area of ​​the aforementioned heat-insulating surface, if defined as the opening ratio, is between 20% and 50%.

5. The channel burner as described in claim 1 or 2, wherein, The aforementioned at least one main orifice includes a plurality of the aforementioned main orifices arranged side by side around the central axis of the aforementioned nozzle; the aforementioned at least one secondary orifice includes a plurality of the aforementioned secondary orifices arranged side by side around the central axis of the aforementioned nozzle; the aforementioned nozzle includes an ignition nozzle having a small-diameter orifice, the diameter of which is smaller than that of the aforementioned secondary orifices, and is configured to eject the aforementioned gaseous fuel from the side of the central axis of the aforementioned nozzle that is closer to the central axis of the aforementioned nozzle than the plurality of the aforementioned main orifices and the plurality of the aforementioned secondary orifices.

6. The channel burner as described in claim 5, wherein, The device further includes an ignition device disposed in a channel having an inner wall surface that defines the aforementioned exhaust flow path, and the aforementioned at least one nozzle comprising a plurality of the aforementioned nozzles, wherein the nozzle disposed closest to the aforementioned ignition device among the plurality of the aforementioned nozzles is the aforementioned ignition nozzle.

7. The channel burner as described in claim 1 or 2, wherein, The aforementioned at least one nozzle comprises a plurality of the aforementioned nozzles arranged side by side along the left-right direction, and the aforementioned pair of plate-like members are arranged side by side along the up-down direction.

8. The channel burner as described in claim 7, wherein, The aforementioned at least one main hole includes a plurality of the aforementioned main holes, and the aforementioned at least one secondary hole includes a plurality of the aforementioned secondary holes, the plurality of the aforementioned main holes and the plurality of the aforementioned secondary holes being alternately arranged side by side around the central axis of the aforementioned nozzle.

9. The channel burner as described in claim 8, wherein, The plurality of the aforementioned nozzles includes: a left nozzle and a right nozzle adjacent to the left nozzle. When viewing the aforementioned channel burner from the downstream side of the aforementioned exhaust flow path, if the angle of a virtual line extending upward from the central axis of the aforementioned nozzle is defined as 0 degrees, and the aforementioned angle increases as the aforementioned nozzle rotates clockwise around its central axis, and the aforementioned angle when the aforementioned virtual line completes one revolution is defined as 360 degrees, the aforementioned left nozzle and the aforementioned right nozzle each include: an upper secondary orifice, which is one of the plurality of the aforementioned secondary orifices, and the aforementioned angle is between 0 degrees and 10 degrees or between 350 degrees and 360 degrees; and a lower secondary orifice, which is one of the plurality of the aforementioned secondary orifices, and the aforementioned angle is between 170 degrees and 190 degrees.

10. The channel burner as described in claim 9, wherein, The aforementioned left nozzle contains a right auxiliary hole, which is one of a plurality of the aforementioned auxiliary holes, and the aforementioned angle position is between 80 degrees and 100 degrees. The aforementioned right nozzle contains a left auxiliary hole, which is one of a plurality of the aforementioned auxiliary holes, and the aforementioned angle position is between 260 degrees and 280 degrees.

11. The channel burner as described in claim 9, wherein, The aforementioned nozzle further includes a second auxiliary hole, which is configured to spray the aforementioned gaseous fuel at a spray angle of 50 degrees to 90 degrees relative to the central axis of the aforementioned nozzle. The aforementioned angle position of the aforementioned second auxiliary hole is 80 degrees to 100 degrees, or 260 degrees to 280 degrees.

12. The channel burner as described in claim 1 or 2, wherein, The aforementioned gaseous fuel is hydrogen or hydrocarbon gas.

13. A gas turbine system comprising: a gas turbine for use with hydrogen as fuel, and a channel burner as described in claim 1 or 2.

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