Duct burner and gas turbine system

Abstract

To enable stable combustion.SOLUTION: A duct burner arranged in an exhaust gas flow path through which exhaust gas discharged from a gas turbine circulates, comprises at least one nozzle that ejects gas fuel into the exhaust gas flow path, and a flame holder including a pair of plate-shaped members located with the nozzle therebetween and moving away from a central axis of the nozzle as they move toward the downstream side of the exhaust gas flow path. The nozzle includes at least one sub-hole configured to eject gas fuel along a flame-holding surface on the downstream side of the exhaust gas flow path of the plate-shaped member, and at least one main hole that is larger in diameter than the sub-hole and configured to eject gas fuel at an angle toward the central axis of the nozzle relative to the sub-hole.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a duct burner and a gas turbine system including the duct burner. [Background technology]

[0002] For example, as disclosed in Non-Patent Document 1, in a gas turbine cogeneration system equipped with a gas turbine and a heat recovery boiler, a duct burner may be provided upstream of the heat recovery boiler in order to increase the amount of heat recovered by the heat recovery boiler. The duct burner injects fuel into the exhaust gas discharged from the gas turbine and performs combustion heating by utilizing the oxygen contained in the exhaust gas. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] IHI Technical Report VOL.49 No.2(2009-6) P103-P107 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the oxygen concentration in the exhaust gas is low, it is not easy to achieve stable combustion with the duct burner.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a duct burner capable of stable combustion. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the duct burner of the present disclosure is a duct burner that is arranged in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows, and is equipped with at least one nozzle that sprays gas fuel into the exhaust gas flow path, and a flame stabilizer that includes a pair of plate-shaped members that are located on opposite sides of the nozzle and move away from the central axis of the nozzle as they approach the downstream side of the exhaust gas flow path, and the nozzle includes at least one sub-hole configured to spray the gas fuel along a flame-stabilizing surface of the plate-shaped member on the downstream side of the exhaust gas flow path, and at least one main hole that is larger in diameter than the sub-hole and configured to spray the gas fuel at a tilt toward the central axis of the nozzle more than the sub-hole. Effect of the Invention

[0007] According to the duct burner of the present disclosure, stable combustion can be achieved. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a gas turbine system including a duct burner according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a schematic configuration of a nozzle according to an embodiment. [Diagram 3] 5 is a side cross-sectional view of a nozzle according to one embodiment (view taken along line AA in FIG. 4). [Figure 4] FIG. 2 is a diagram illustrating a schematic configuration of a nozzle according to an embodiment. [Diagram 5] FIG. 2 is a diagram illustrating a schematic configuration of an ignition nozzle according to an embodiment. [Figure 6] FIG. 2 is a diagram illustrating a schematic configuration of a left nozzle and a right nozzle according to an embodiment. [Figure 7] FIG. 2 is a schematic diagram illustrating a nozzle configuration according to some embodiments. [Figure 8] FIG. 11 is a diagram showing whether stable combustion has been performed in a duct burner according to an embodiment. [Figure 9] FIG. 11 is a diagram showing whether stable combustion has been performed in a duct burner according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a duct burner according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment shows one aspect of the present disclosure, and does not limit the present disclosure. The embodiment can be arbitrarily modified within the scope of the technical concept of the present disclosure.

[0010] <Gas turbine> Fig. 1 is a diagram that shows a schematic configuration of a gas turbine system 100 that includes a duct burner 1 according to some embodiments. As shown in Fig. 1, the gas turbine system 100 includes a gas turbine 110, an exhaust gas flow path 120 through which exhaust gas G discharged from the gas turbine 110 flows, a heat recovery steam generator 130 that is disposed in the exhaust gas flow path 120, and a duct burner 1 according to some embodiments.

[0011] The gas turbine 110 includes a compressor 112, a combustor 114, and a turbine 116. The compressor 112 compresses air A1 supplied from the outside to generate compressed air A2. The combustor 114 generates combustion gas A4 by injecting fuel A3 into the compressed air A2 generated by the compressor 112 and combusting the fuel A3. The fuel A3 is, but is not limited to, hydrogen gas. In some embodiments, the fuel A3 is a hydrocarbon gas such as LPG or LNG.

[0012] The turbine 116 is rotationally driven by the passage of the combustion gas A4 generated by the combustor 114, and converts thermal energy of the combustion gas A4 into rotational energy. The turbine 116 is connected to the compressor 112 via a rotating shaft 113, and transmits the rotational energy to the compressor 112. The compressor 112 is driven by 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 generates electric power by using the rotational energy of the turbine 116.

[0013] The exhaust gas flow path 120 is defined by an inner wall surface 124 of a cylindrical duct 122 (see FIG. 2). The exhaust heat recovery boiler 130 generates steam by heating feed water using thermal energy contained in the exhaust gas G. The exhaust gas G that has passed through the exhaust heat recovery boiler 130 is supplied to, but is not limited to, a CO2 absorption tower that absorbs CO2 from the exhaust gas G into an absorbing liquid, for example.

[0014] <Duct burner> (composition) The duct burner 1 is disposed upstream of the exhaust gas passage 120 from the heat recovery steam generator 130. Fig. 2 is a diagram showing a schematic configuration of the duct burner 1 according to one embodiment, and is a diagram (front view) of the duct burner 1 as viewed from the downstream side of the exhaust gas passage 120.

[0015] In one embodiment, as shown in Fig. 2, the duct burner 1 includes a plurality of fuel supply pipes 2 extending in the left-right direction D1 through the exhaust gas passage 120. The plurality of fuel supply pipes 2 are arranged at intervals from one another in the up-down direction D2. Each of the plurality of fuel supply pipes 2 has a cylindrical shape, and gas fuel F supplied from a supply source (not shown) flows through the inside of the plurality of fuel supply pipes 2. The gas fuel F is not particularly limited, but is hydrogen gas. The gas fuel F may be a hydrocarbon gas such as LPG or LNG.

[0016] The duct burner 1 includes a nozzle 4 connected to a fuel supply pipe 2 and ejecting gas fuel F into an exhaust gas flow path 120, and a flame stabilizer 6 having a pair of plate-like members 8A, 8B positioned on opposite sides of the nozzle 4. In one embodiment, as shown in Fig. 2, a plurality of nozzles 4 are provided in one fuel supply pipe 2 lined up along the left-right direction D1 (a manifold is formed).

[0017] The pair of plate-shaped members 8A, 8B are arranged along the up-down direction D2 and include 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. The upper plate-shaped member 8A and the lower plate-shaped member 8B are arranged so that at least a portion of them overlap with each other in the left-right direction D1 when viewed from the front.

[0018] 2, a plurality of nozzles 4 are provided in a line along the left-right direction D1 on one fuel supply pipe 2, but the present disclosure is not limited to this form. The duct burner 1 may include a fuel supply pipe 2 extending in the up-down direction D2, and a plurality of nozzles 4 provided in a line along the up-down direction D2 on the fuel supply pipe 2. In this case, the pair of plate-like members 8A, 8B are disposed on opposite sides of each other in the left-right direction D1 with the nozzle 4 therebetween.

[0019] In one embodiment, as shown in FIG. 2, the duct burner 1 further includes an ignition device 30 that ignites the gas fuel F. The ignition device 30 is provided in the duct 122 and is located downstream of the nozzle 4 in the exhaust gas flow passage 120. The ignition device 30 may be configured to be capable of igniting the gas fuel F, and may be configured to use, for example, pilot ignition that ignites the gas fuel F with a flame formed by a small burner, or direct ignition that ignites the gas fuel F by spark discharge from an ignition plug. The ignition device 30 may be provided for each fuel supply pipe 2. Of the multiple nozzles 4 provided in one fuel supply pipe 2, the nozzle 4 that is disposed closest to the ignition device 30 is the ignition nozzle 20(4). The multiple nozzles 4 provided in one fuel supply pipe 2 include a left nozzle 40(4) and a right nozzle 42(4) adjacent to the left nozzle 40 on the right side. The configurations of the ignition nozzle 20, the left nozzle 40, and the right nozzle 42 will be described later.

[0020] Fig. 3 is a side cross-sectional view of a nozzle 4 according to one embodiment. As shown in Fig. 3, the nozzle 4 includes a main hole 10 and a sub-hole 12. The sub-hole 12 is configured to eject the gas fuel F along a flame-holding surface 14 downstream of an exhaust gas flow passage 120 of the upper plate-shaped member 8A or the lower plate-shaped member 8B. The main hole 10 has a larger diameter than the sub-hole 12. The main hole 10 is configured to eject the gas fuel F at a tilt toward the central axis O of the nozzle 4 relative to the sub-hole 12.

[0021] A specific configuration example of the main hole 10 and the sub-hole 12 according to one embodiment will be described. The main hole 10 and the sub-hole 12 each extend linearly. The angle formed by a 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 defined as the main hole ejection angle θ1. The angle formed by a virtual second straight line L2 extending in the ejection direction of the sub-hole 12 and the central axis O of the nozzle 4 is defined as the sub-hole ejection angle θ2. The main hole ejection angle θ1 is equal to or greater than 20 degrees and less than 40 degrees. The sub-hole ejection angle θ2 is equal to or greater than 40 degrees and less than 50 degrees.

[0022] As shown in Fig. 3, each of the upper plate member 8A and the lower plate member 8B moves away from the central axis O of the nozzle 4 toward the downstream side of the exhaust gas passage 120. Each of the upper plate member 8A and the lower plate member 8B is linearly symmetrical with respect to the central axis O of the nozzle. Each of the upper plate member 8A and the lower plate member 8B is configured so that the angle θ3 of the flame holding surface 14 with respect to the central axis O of the nozzle 4 is equal to or greater than 40 degrees and equal to or less than 50 degrees. In one embodiment, the angle θ3 of the flame holding surface 14 is 45 degrees. The angle θ3 of the flame holding surface 14 is the same angle as the sub-hole ejection angle θ2.

[0023] Each of the upper plate-like member 8A and the lower plate-like member 8B has a plurality of through holes 18 formed therein, extending from the flame-holding surface 14 to the surface 16 opposite the flame-holding surface 14. If the ratio of the area of ​​the plurality of through holes 18 to the area of ​​the flame-holding surface 14 including the area of ​​the plurality of through holes 18 is taken as the aperture ratio, the aperture ratio is 20% or more and 50% or less. The number of through holes 18 is not particularly limited, and may be one, or may be two or more.

[0024] FIG. 4 is a diagram showing a schematic configuration of the nozzle 4 according to an embodiment, and is a diagram (front view) of the nozzle 4 viewed from the downstream side of the exhaust gas flow path 120. In one embodiment, as shown in FIG. 4, four main holes 10 and four sub-holes 12 are formed in the nozzle 4. The four main holes 10 are arranged symmetrically around the central axis O of the nozzle 4 with respect to the central axis O of the nozzle. The four sub-holes 12 are arranged symmetrically around the central axis O of the nozzle 4 with respect to the central axis O of the nozzle. The four main holes 10 and the four sub-holes 12 are arranged alternately and evenly around the central axis O of the nozzle 4. That is, the pitch angle α is equal to 45 degrees around the central axis O of the nozzle 4. 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 sub-hole 12 are the same distance from the central axis O of the nozzle 4. In addition, the cross-sectional shape of the main hole 10 and the sub-hole 12 is circular.

[0025] FIG. 5 is a diagram showing a schematic configuration of an ignition nozzle 20 according to an embodiment. As shown in FIG. 5, the ignition nozzle 20 is formed with a small diameter hole 21 configured to eject the gas fuel F from the central axis O side of the nozzle 4 relative to the four main holes 10 and the four sub-holes 12. The small diameter hole 21 has a smaller diameter than each of the four sub-holes 12. In the embodiment shown in FIG. 5, the small diameter hole 21 extends linearly along the central axis O of the nozzle 4. The small diameter hole 21 is located radially inward of the nozzle 4 relative to the four main holes 10 and the four sub-holes 12. The small diameter hole 21 is formed in the tip surface 23 of the ignition nozzle 20. Each of the main hole 10 and the sub-hole 12 is formed in an extension surface 27 extending from the tip surface 23 of the ignition nozzle 20 to a side surface 25. In some embodiments, if the angle formed by a virtual straight line extending in the ejection direction of the small diameter hole 21 and the central axis O of the nozzle 4 is taken as the small diameter hole ejection angle, this small diameter hole ejection angle is smaller than each of the main hole ejection angle θ1 and the sub-hole ejection angle θ2. Note that the nozzle 4 illustrated in Fig. 3 also has the main hole 10 and the sub-hole 12 formed on the extension surface.

[0026] Fig. 6 is a diagram showing a schematic configuration of the left nozzle 40(4) and the right nozzle 42(4) according to one embodiment. As shown in Fig. 6, when the duct burner 1 is viewed from the downstream side of the exhaust gas passage 120, the angular position θ of a 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 nozzle 4 rotates clockwise around the central axis O as the center of rotation, and the angular position θ when the virtual line L3 makes one rotation is defined as 360 degrees.

[0027] 6, each of the left nozzle 40 and the right nozzle 42 includes an upper sub-hole 44 (12) of the multiple sub-holes 12 whose angular position θ is between 0 degrees and 10 degrees, or between 350 degrees and 360 degrees, and a lower sub-hole 46 (12) whose angular position θ is between 170 degrees and 190 degrees. The left nozzle 40 includes a right sub-hole 48 (12) whose angular position θ is between 80 degrees and 100 degrees. The right nozzle 42 includes a left sub-hole 50 (12) whose angular position θ is between 260 degrees and 280 degrees.

[0028] FIG. 7 is a diagram that illustrates a schematic configuration of a nozzle 4 according to some embodiments. In the embodiment illustrated in FIG. 7, the nozzle 4 further includes a second sub-hole 54 in addition to the main hole 10 and the sub-hole 12. The second sub-hole 54 includes a right-side second sub-hole 54A (54) whose angular position θ is 80 degrees or more and 100 degrees or less, and a left-side second sub-hole 54B (54) whose angular position θ is 260 degrees or more and 280 degrees or less. The second sub-hole 54 is configured to eject the gas fuel F at an ejection angle of 50 degrees or more and 90 degrees or less with respect to the central axis O of the nozzle 4. In other words, since a pair of plate-shaped members 8A, 8B are not arranged in the left-right direction D1 of the nozzle 4, the second sub-hole 54 is not configured to eject the gas fuel F along the flame-holding surface 14, and prioritizes improving the flame-holding effect. The ejection angle of the second sub-hole 54 is greater than the sub-hole ejection angle θ2. The second sub-hole 54 may have the same diameter as the sub-hole 12, or may have a diameter different from that of the sub-hole 12.

[0029] 7, the second sub-hole 54 has a larger ejection angle than the right sub-hole 48 and the left sub-hole 50 illustrated in FIG 6. That is, the gas fuel F ejected from the second sub-hole 54 can reach the adjacent nozzle 4 in a shorter distance than the gas fuel F ejected from the right sub-hole 48 and the left sub-hole 50. For this reason, a nozzle 4 having the second sub-hole 54 can quickly ignite a nozzle 4 adjacent to itself.

[0030] (Action and effect) The action and effect of the duct burner 1 according to one embodiment will be described. FIG. 8 is a graph showing whether stable combustion has been performed by the duct burner 1 according to one embodiment, 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. Stable combustion by the duct burner 1 is a state in which the duct burner 1 forms a flame by burning the gas fuel F. The oxygen concentration of the exhaust gas G is the concentration of oxygen contained in the exhaust gas G flowing into the duct burner 1. The temperature of the exhaust gas G is the temperature of the exhaust gas G flowing into the duct burner 1.

[0031] In Fig. 8, the plots of ● indicate that stable combustion was performed in the duct burner 1 according to one embodiment, the plots of ◯ indicate that stable combustion was performed in the duct burner equipped with a conventional nozzle, and the plots of × indicate that stable combustion was not performed in the duct burner equipped with a conventional nozzle. The conventional nozzle is a nozzle in which only multiple main holes having equal ejection angles are formed, and no sub-holes are formed. Furthermore, the duct burner equipped with a conventional nozzle does not have a flame holding mechanism installed in the nozzle, the nozzle base is blown off, and the flame is held in the vicinity of the flame holder of the duct burner.

[0032] The main factors as to whether or not the duct burner 1 performs stable combustion are the oxygen concentration of the exhaust gas G and the temperature of the exhaust gas G. If the oxygen concentration of the exhaust gas G is low, the combustion of the duct burner 1 becomes unstable. Similarly, if the temperature of the exhaust gas G is low, the combustion of the duct burner 1 becomes unstable. As shown in FIG. 8, in the duct burner 1 according to an embodiment, if the oxygen concentration of the exhaust gas G is 7% or more, stable combustion can be performed even if the temperature of the exhaust gas G is 300 degrees. On the other hand, in the conventional duct burner 1, if the oxygen concentration of the exhaust gas G is 8% or 11%, stable combustion cannot be performed if the temperature of the exhaust gas G is 300 degrees. In the conventional duct burner 1, in order to perform 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. As shown in FIG. 8, the stable combustion boundary B1 of the duct burner 1 according to an embodiment is on the lower temperature side than the stable combustion boundary B2 of the conventional duct burner in the low oxygen region (14% or less). Therefore, compared with the conventional duct burner 1, the duct burner 1 according to one embodiment can expand the conditions under which stable combustion is possible.

[0033] In the duct burner 1, since the oxygen concentration contained in the exhaust gas G is low, it may be difficult to perform stable combustion. According to one embodiment, the sub-hole 12 ejects the gas fuel F along the flame-holding surface 14, and therefore, mixing of the gas fuel F and the exhaust gas G in the region C1 (see FIG. 3) near where the gas fuel F is ejected from the nozzle 4 can be promoted, and flame fluctuation can be suppressed and flame stabilization can be strengthened. Furthermore, since the main hole 10 ejects the gas fuel F at an inclination toward the central axis O of the nozzle more than the sub-hole 12, slow combustion due to a long flame can be promoted. Furthermore, the generation of nitrogen oxides (NOx) can be suppressed. As a result, the duct burner 1 can perform stable combustion.

[0034] According to one embodiment, by setting the ejection angle θ1 of the main hole 10 (the elevation angle with respect to the central axis O of the nozzle 4) to 40 degrees or less, slow combustion due to flame lengthening can be promoted. On the other hand, if the ejection angle θ1 of the main hole 10 is less than 20 degrees, the flame lengthening becomes excessive, which may affect the heat absorption characteristics of the exhaust heat recovery boiler 130 that supplies the exhaust gas G heated by the duct burner 1. In addition, by setting the ejection angle θ2 of the sub-hole 12 to 40 degrees or more, the gas fuel F is burned from the root of the tip of the nozzle 4, and the nozzle 4 can have a high flame-holding effect. In addition, by setting the ejection angle θ2 of the sub-hole 12 to 50 degrees or more, the sub-hole flame formed by the combustion of the gas fuel F ejected from the sub-hole 12 may come into contact with the flame-holding surface 14, which may reduce the durability of the flame stabilizer 6. On the other hand, if the ejection angle θ2 of the sub-hole 12 is set to less than 40 degrees, the sub-hole flame will move away from the flame stabilizer 6, reducing the flame-stabilizing effect. For this reason, by setting the ejection angle θ1 of the main hole 10 to be equal to or greater than 20 degrees and equal to or less than 40 degrees, and the ejection angle θ2 of the sub-hole 12 to be equal to or greater than 40 degrees and less than 50 degrees, stable combustion in the duct burner 1 can be achieved. Note that the angle θ3 of the flame-stabilizing surface 14 is often set to 45 degrees. For this reason, by configuring the ejection angle θ2 of the sub-hole 12 to be equal to or greater than 40 degrees and less than 50 degrees, the duct burner 1 can ensure a certain flame-stabilizing effect while suppressing a decrease in the durability of the flame stabilizer 6.

[0035] According to one embodiment, the upper plate member 8A and the lower plate member 8B each have a through hole 18, so that the amount of exhaust gas G supplied to the vicinity of where the gas fuel F is ejected from the nozzle 4 can be adjusted. If the aperture ratio is less than 20%, the amount of exhaust gas G passing through the through hole 18 is small, and the amount of exhaust gas G required to cool the flame stabilizer 6 is insufficient, which may cause the flame stabilizer 6 to become red hot. If the aperture ratio exceeds 50%, there is a risk that the flame stabilization effect may decrease depending on the type of gas fuel F. Therefore, according to one embodiment, the aperture ratio is 20% or more and 50% or less, so that the generation of NOx can be suitably suppressed.

[0036] According to one embodiment, the ignition nozzle 20 is formed with small diameter holes 21 that eject the gas fuel F from the central axis O side of the nozzle 4 relative to the four main holes 10 and the four sub-holes 12. This expands the area C2 (see FIG. 5) where the gas fuel F ignites and burns when the duct burner 1 is started. This improves the ignition performance of the duct burner 1.

[0037] According to one embodiment, the ignition nozzle 20 is disposed closest to the ignition device 30 among the multiple nozzles 4. Therefore, it is possible to improve the ignition performance of the duct burner 1 without making all or most of the multiple nozzles 4 ignition nozzles 20. The duct burner 1 may be provided with multiple ignition nozzles 20. The ignition nozzle 20 may be a nozzle 4 other than the nozzle 4 closest to the ignition device 30 among the multiple nozzles 4.

[0038] According to one embodiment, the four main holes 10 and the four sub-holes 12 are alternately arranged around the central axis O of the nozzle 4. Therefore, the gas fuel F is ejected evenly from the four main holes 10 without bias with respect to the central axis O of the nozzle 4, and is ejected evenly from the four sub-holes 12 without bias with respect to the central axis O of the nozzle 4. Therefore, slow combustion due to the long flame can be smoothly continued.

[0039] The exhaust gas G passes through the through holes 18 formed in the upper plate-shaped member 8A and the lower plate-shaped member 8B, and is supplied to a region C1 in the vicinity of where the gas fuel F is ejected from the nozzle 4. That is, the exhaust gas G is supplied from above or below the nozzle 4. According to one embodiment, since the left nozzle 40 and the right nozzle 42 each include an upper sub-hole 44 and a lower sub-hole 46, the gas fuel F ejected from the upper sub-hole 44 or the lower sub-hole 46 can be quickly mixed with the exhaust gas G.

[0040] According to one embodiment, the left nozzle 40 includes the right sub-hole 48 and the right nozzle 42 includes the left sub-hole 50, so that the left nozzle 40 can ignite the right nozzle 42, or the right nozzle 42 can ignite the left nozzle 40. If the hole diameter of the right sub-hole 48 or the left sub-hole 50 is made as large as that of the main hole 10, for example, the flames of the left nozzle 40 and the right nozzle 42 may come into contact with each other, causing a rise in temperature and the generation of NOx. For this reason, it is desirable that the sub-hole 12 is open in the left-right direction D1.

[0041] In one embodiment, the gas fuel F is hydrogen, but the present disclosure is not limited to this embodiment. In another embodiment, the gas fuel F is LPG. Fig. 9 is a graph showing whether stable combustion has been performed in the duct burner 1 according to another embodiment, 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.

[0042] 9, the plots of ● mean that stable combustion was performed in the duct burner 1 according to another embodiment, and the plots of + mean that stable combustion was performed in the duct burner 1 according to another embodiment. Similarly, the plots of ◯ mean that stable combustion was performed in the duct burner equipped with a conventional nozzle, and the plots of × mean that stable combustion was not performed in the duct burner equipped with a conventional nozzle.

[0043] As shown in FIG. 9, in the duct burner 1 according to another embodiment, if the oxygen concentration of the exhaust gas G is 12%, stable combustion can be performed even if the temperature of the exhaust gas G is 400 degrees. On the other hand, in the conventional duct burner 1, when the oxygen concentration of the exhaust gas G is 12%, stable combustion cannot be performed if the temperature of the exhaust gas G is 400 degrees. In the conventional duct burner 1, in order to perform stable combustion when the oxygen concentration of the exhaust gas G is 10%, the temperature of the exhaust gas G needs to be higher than 400 degrees (about 650 degrees). As shown in FIG. 9, the stable combustion boundary B3 of the duct burner 1 according to another embodiment is on the lower temperature side than the stable combustion boundary B4 of the conventional duct burner in the low oxygen region (14% or less). Therefore, the duct burner 1 according to another embodiment can expand the conditions under which stable combustion is possible, compared to the conventional duct burner 1.

[0044] The contents described in each of the above embodiments can be understood, for example, as follows.

[0045] [1] The duct burner (1) according to the present disclosure is A duct burner disposed in an exhaust gas passage (120) through which exhaust gas (G) discharged from a gas turbine (110) flows, At least one nozzle (4) for injecting a gas fuel (F) into the exhaust gas passage; a flame stabilizer (6) including a pair of plate-shaped members (8A, 8B) positioned on opposite sides of the nozzle and moving away from a central axis (O) of the nozzle toward a downstream side of the exhaust gas flow path, The nozzle is at least one sub-hole (12) configured to eject the gas fuel along a flame-holding surface (14) downstream of the exhaust gas flow passage of the plate-shaped member; and at least one main hole (10) that has a larger diameter than the sub-hole and is configured to eject the gas fuel at an angle closer to the central axis of the nozzle than the sub-hole.

[0046] Duct burners can have difficulty in stably burning because the oxygen concentration in exhaust gas is low. According to the configuration described in [1] above, the sub-hole ejects gas fuel along the flame-holding surface, which promotes mixing of the gas fuel and exhaust gas in the vicinity where the gas fuel is ejected from the nozzle, suppresses flame fluctuation, and strengthens flame stabilization. Furthermore, the main hole ejects gas fuel at an angle closer to the central axis of the nozzle than the sub-hole, which promotes slow combustion by making the flame longer (and also suppresses the generation of nitrogen oxides). This allows the duct burner to achieve stable combustion.

[0047] [2] In some embodiments, in the configuration described in [1] above, The main hole is configured with a jetting angle (θ1) of 20 degrees or more and less than 40 degrees with respect to the central axis of the nozzle, The sub-hole is configured with a jetting angle (θ2) of 40 degrees or more and less than 50 degrees with respect to the central axis of the nozzle, The angle (θ3) of the flame stabilizing surface with respect to the central axis of the nozzle is equal to or greater than 40 degrees and equal to or less than 50 degrees.

[0048] According to the configuration described in [2] above, by setting the jet angle of the main hole (the elevation angle relative to the central axis of the nozzle) to less than 40 degrees, slow combustion due to a long flame can be promoted. On the other hand, if the jet angle of the main hole is less than 20 degrees, the flame becomes excessively long, which may affect the heat absorption characteristics of the waste heat boiler that supplies the exhaust gas heated by the duct burner. In addition, by setting the jet angle of the sub-hole to 40 degrees or more, the nozzle can have a high flame-holding effect. Therefore, by setting the jet angle of the main hole to 20 degrees or more and 40 degrees or less, and the jet angle of the sub-hole to 40 degrees or more and less than 50 degrees, stable combustion of the duct burner can be achieved.

[0049] [3] In some embodiments, in the configuration described in [1] or [2] above, The plate-like member has at least one through hole (18) formed therein, the through hole (18) extending from the flame-holding surface to a surface (16) opposite the flame-holding surface.

[0050] According to the configuration described in [3] above, it is possible to adjust the amount of exhaust gas supplied to the vicinity of the outlet of the gas fuel from the nozzle.

[0051] [4] In some embodiments, in the configuration described in [3] above, A plurality of the through holes are formed in the plate-like member, If the ratio of the area of ​​the plurality of through holes to the area of ​​the flame-holding surface is taken as an aperture ratio, the aperture ratio is 20% or more and 50% or less.

[0052] If the aperture ratio is less than 20%, the amount of exhaust gas passing through the through holes is small, and the amount of exhaust gas required to cool the flame holder is insufficient, which may cause the flame holder to become red hot. If the aperture ratio exceeds 50%, the flame holding effect may decrease depending on the type of gas fuel. According to the configuration described in [4] above, the aperture ratio is 20% or more and 50% or less, so that the generation of nitrogen oxides can be suitably suppressed.

[0053] [5] In some embodiments, in the configuration according to any one of [1] to [4] above, the at least one main hole includes a plurality of the main holes arranged around a central axis of the nozzle; the at least one sub-hole includes a plurality of the sub-holes arranged around a central axis of the nozzle; The nozzle includes an ignition nozzle (20) having a small diameter hole (21) formed therein, the small diameter hole (21) being smaller in diameter than the sub-hole and configured to eject the gas fuel from the central axis side of the nozzle further than the main holes and the sub-holes.

[0054] According to the configuration described in [5] above, the small diameter hole ejects the gas fuel from the central axis side of the nozzle further than the main holes and sub-holes, so that the area in which the gas fuel ignites and burns when the duct burner is started is expanded, thereby improving the ignition ability of the duct burner.

[0055] [6] In some embodiments, in the configuration described in [5] above, the exhaust gas passage further includes an ignition device (30) provided in a duct (122) having an inner wall surface (124) that defines the exhaust gas flow path, the at least one nozzle includes a plurality of the nozzles, Of the plurality of nozzles, the nozzle disposed closest to the ignition device is the ignition nozzle.

[0056] According to the configuration described in [6] above, the ignition performance of the duct burner can be improved without making all or most of the multiple nozzles ignition nozzles.

[0057] [7] In some embodiments, in the configuration according to any one of [1] to [6] above, The at least one nozzle includes a plurality of the nozzles arranged along a left-right direction (D1), The pair of plate-like members are arranged side by side in the up-down direction (D2).

[0058] According to the configuration described in [7] above, a duct burner can be provided in which a plurality of nozzles are arranged in the left-right direction and a pair of plate-shaped members are arranged in the up-down direction.

[0059] [8] In some embodiments, in the configuration described in [7] above, the at least one main hole includes a plurality of the main holes, the at least one sub-hole includes a plurality of the sub-holes, The plurality of main holes and the plurality of sub-holes are arranged alternately around a central axis of the nozzle.

[0060] According to the configuration described in [8] above, the gas fuel is ejected from the multiple main holes evenly and without bias with respect to the central axis of the nozzle, and from the multiple sub-holes evenly and without bias with respect to the central axis of the nozzle. This allows the slow combustion due to the long flame to continue smoothly.

[0061] [9] In some embodiments, in the configuration described in [8] above, The plurality of nozzles include a left nozzle (40) and a right nozzle (42) adjacent to the left nozzle on the right side, When the duct burner is viewed from the downstream side of the exhaust gas flow path, the angular position (θ) of a virtual line (L3) extending upward from the central axis of the nozzle is defined as 0 degrees, the angular position increases as the nozzle rotates clockwise around the central axis of the nozzle as the center of rotation, and the angular position when the virtual line makes one rotation is defined as 360 degrees. Each of the left nozzle and the right nozzle has an upper sub-hole (44) among the plurality of sub-holes, the upper sub-hole having an angular position greater than or equal to 0 degrees and less than or equal to 10 degrees, or greater than or equal to 350 degrees and less than or equal to 360 degrees; and a lower sub-hole (46), which is one of the plurality of sub-holes, the angular position of which is greater than or equal to 170 degrees and less than or equal to 190 degrees.

[0062] The exhaust gas passes through through holes formed in each of a pair of plate-like members arranged in the vertical direction and is supplied to the vicinity of where the gas fuel is ejected from the nozzle. In other words, the exhaust gas is supplied from above or below the nozzle. According to the configuration described in [9] above, since each of the left nozzle and the right nozzle includes an upper sub-hole and a lower sub-hole, the gas fuel ejected from the upper sub-hole and the lower sub-hole can be quickly mixed with the exhaust gas.

[0063]

[10] In some embodiments, in the configuration described in [9] above, the left nozzle includes a right sub-hole that is one of the plurality of sub-holes and that has an angular position that is greater than or equal to 80 degrees and less than or equal to 100 degrees; The right nozzle includes a left sub-hole that is one of the plurality of sub-holes and has an angular position greater than or equal to 260 degrees and less than or equal to 280 degrees.

[0064] According to the configuration described in

[10] above, the left nozzle can ignite the right nozzle, or the right nozzle can ignite the left nozzle.

[0065]

[11] In some embodiments, in the configuration described in [9] above, the nozzle further includes a second sub-hole configured to eject the gas fuel at an ejection angle of 50 degrees or more and 90 degrees or less with respect to a central axis of the nozzle; The second sub-hole has an angular position that is greater than or equal to 80 degrees and less than or equal to 100 degrees, or greater than or equal to 260 degrees and less than or equal to 280 degrees.

[0066] According to the configuration described in

[11] above, the second sub-hole has a larger ejection angle than the right sub-hole and the left sub-hole described in

[10] above, so that a nozzle having the second sub-hole can quickly ignite the nozzles adjacent to it.

[0067]

[12] In some embodiments, in the configuration according to any one of [1] to

[11] above, The gas fuel is hydrogen gas or a hydrocarbon gas.

[0068] According to the configuration described in

[12] above, a duct burner that uses hydrogen gas or a hydrocarbon gas can achieve stable combustion.

[0069]

[13] A gas turbine system according to the present disclosure includes: A gas turbine that uses hydrogen gas as fuel; and a duct burner according to any one of [1] to

[12] above.

[0070] According to the configuration described in

[13] above, a gas turbine system equipped with a duct burner that provides stable combustion can be provided. [Explanation of symbols]

[0071] 1 Duct burner 2 Fuel supply pipe 4 Nozzles 6 Flame holder 8A Upper plate member 8B Lower plate member 10 Main hole 12 Secondary hole 14 Flame holding surface 18 Through hole 20 Ignition nozzle 21 Small diameter hole 30 Ignition device 40 Left nozzle 42 Right nozzle 44 Upper collateral foramen 46 Lower secondary foramen 48 Right side secondary hole 50 Left secondary hole 54 Second sub-hole 100 Gas Turbine System 110 Gas Turbine 112 Compressor 113 Rotational Axis 114 Combustor 116 Turbine 120 Exhaust gas flow path 122 Duct 124 Inner wall surface of duct 130 Waste heat recovery boiler 140 Generator A1 Air A2 Compressed air A3 fuel A4 Combustion gas D1 Left / right direction D2 Vertical direction F Gas fuel G. Exhaust gas L1 1st straight line L2 2nd straight line L3 Virtual Line O Nozzle central axis

Claims

1. A duct burner that is disposed in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows, At least one nozzle that ejects gas fuel into the exhaust gas flow passage; a flame stabilizer including a pair of plate-shaped members located on opposite sides of the nozzle and moving away from a central axis of the nozzle toward a downstream side of the exhaust gas flow path, The nozzle is at least one sub-hole configured to eject the gas fuel along a flame-stabilizing surface of the plate-shaped member downstream of the exhaust gas flow passage; at least one main hole having a diameter larger than that of the sub-hole and configured to eject the gas fuel at a tilt toward a central axis of the nozzle relative to the sub-hole; Duct burner.

2. The main hole is configured with an ejection angle of 20 degrees or more and less than 40 degrees with respect to a central axis of the nozzle, The sub-hole is configured with an ejection angle of 40 degrees or more and less than 50 degrees with respect to a central axis of the nozzle, The angle of the flame stabilizing surface with respect to the central axis of the nozzle is greater than or equal to 40 degrees and less than or equal to 50 degrees.

2. The duct burner according to claim 1.

3. At least one through hole is formed in the plate-like member, the through hole extending from the flame-holding surface to a surface opposite the flame-holding surface.

3. A duct burner according to claim 1 or 2.

4. A plurality of the through holes are formed in the plate-like member, When the ratio of the area of ​​the plurality of through holes to the area of ​​the flame stabilizing surface is defined as an aperture ratio, the aperture ratio is 20% or more and 50% or less.

4. A duct burner according to claim 3.

5. the at least one main hole includes a plurality of the main holes arranged around a central axis of the nozzle; the at least one sub-hole includes a plurality of the sub-holes arranged around a central axis of the nozzle; the nozzle includes an ignition nozzle having a small diameter hole formed therein, the small diameter hole being smaller in diameter than the sub-hole and configured to eject the gas fuel from a central axis side of the nozzle than the plurality of main holes and the plurality of sub-holes, 3. A duct burner according to claim 1 or 2.

6. The exhaust gas exhaust system further includes an ignition device provided in a duct having an inner wall surface that defines the exhaust gas flow path, the at least one nozzle includes a plurality of the nozzles, Among the plurality of nozzles, the nozzle disposed closest to the ignition device is the ignition nozzle.

6. A duct burner according to claim 5.

7. The at least one nozzle includes a plurality of the nozzles arranged along a left-right direction, The pair of plate-like members are arranged in the up-down direction.

3. A duct burner according to claim 1 or 2.

8. the at least one main hole includes a plurality of the main holes, the at least one sub-hole includes a plurality of the sub-holes, The plurality of main holes and the plurality of sub-holes are alternately arranged around a central axis of the nozzle.

8. A duct burner according to claim 7.

9. the plurality of nozzles include a left nozzle and a right nozzle adjacent to the left nozzle on the right, When the duct burner is viewed from the downstream side of the exhaust gas flow path, the angular position of a virtual line extending upward from the central axis of the nozzle is defined as 0 degrees, the angular position increases as the nozzle rotates clockwise around the central axis of the nozzle as the center of rotation, and the angular position when the virtual line makes one rotation is defined as 360 degrees. Each of the left nozzle and the right nozzle has an upper sub-hole among the plurality of sub-holes, the upper sub-hole having an angular position greater than or equal to 0 degrees and less than or equal to 10 degrees, or greater than or equal to 350 degrees and less than or equal to 360 degrees; a lower sub-hole, the lower sub-hole being one of the plurality of sub-holes, the angular position of which is greater than or equal to 170 degrees and less than or equal to 190 degrees; 9. A duct burner according to claim 8.

10. the left nozzle includes a right sub-hole that is one of the plurality of sub-holes and that is located at an angular position greater than or equal to 80 degrees and less than or equal to 100 degrees; the right nozzle includes a left sub-hole that is one of the plurality of sub-holes and that has an angular position that is greater than or equal to 260 degrees and less than or equal to 280 degrees; 10. A duct burner according to claim 9.

11. the nozzle further includes a second sub-hole configured to eject the gas fuel at an ejection angle of 50 degrees or more and 90 degrees or less with respect to a central axis of the nozzle; The second sub-hole has an angular position of 80 degrees or more and 100 degrees or less, or 260 degrees or more and 280 degrees or less.

10. A duct burner according to claim 9.

12. The gas fuel is hydrogen gas or a hydrocarbon gas.

3. A duct burner according to claim 1 or 2.

13. A gas turbine that uses hydrogen gas as fuel; The duct burner according to claim 1 or 2, Gas turbine systems.

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