JP4622885B2 - Combustion device and fuel supply method for combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus and a fuel supply method for the combustion apparatus.

  From the standpoint of environmental conservation, reducing NOx emissions in combustion devices is an important issue. Particularly in recent years, gas turbine plants, which are one of the products that use combustion devices, tend to increase in output and efficiency. Accordingly, the combustion gas temperature of the gas turbine combustor used for the gas turbine is also increased. Therefore, the reduction of thermal NOx that is likely to occur under high temperature conditions is an important issue. Therefore, Patent Document 1 discloses a method of suppressing NOx by supplying fuel and combustion air as a plurality of coaxial jets to a combustion chamber and burning them.

  Further, in order to suppress thermal NOx, it is necessary to supply a sufficient amount of combustion air with respect to the fuel amount. However, when a part of the combustion air is used to cool the high-temperature member of the combustor, there is a possibility that the combustion air is reduced by that amount, the fuel-air ratio is reduced, and NOx cannot be suppressed. Therefore, Patent Document 2 discloses a technique that can reduce the amount of cooling air for cooling a gas turbine high-temperature member such as a combustor and use the amount of air as combustion air.

JP 2003-148734 A JP 2001-271654 A

  Here, when considering a gas turbine combustor provided with a plurality of burners for supplying a coaxial jet of fuel and combustion air to the combustion chamber, an air hole is arranged upstream of the combustion chamber and jets the coaxial jet into the combustion chamber. It is necessary to cool the holding member that holds the plate-like member formed. When a plurality of burners are provided, the use of the burner is switched depending on the gas turbine load. Therefore, it is desirable to change the cooling location of the holding member according to the gas turbine load. However, Patent Document 2 does not disclose a method for changing the cooling point of the combustor according to the gas turbine load.

  Accordingly, an object of the present invention is to provide a combustion apparatus and a fuel supply method for the combustion apparatus that can appropriately cool the holding member according to the load and further reduce NOx.

  In the present invention, the plate-like member is held by the holding member, a cooling fuel channel is provided inside the holding member, and the fuel that has flowed through the cooling fuel channel is supplied to the fuel nozzle. A fuel supply method for an apparatus is provided.

  According to the present invention, it is possible to appropriately cool the holding member according to the load, and to provide a combustion apparatus and a fuel supply method for the combustion apparatus that further reduce NOx.

  Examples of the present invention are shown below.

  Hereinafter, a gas turbine combustor will be described as an example of a combustion apparatus. FIG. 1 is a view of the burner as seen from the combustion chamber. FIG. 2 is a system diagram of a gas turbine including a longitudinal section of the combustor.

  The gas turbine includes a compressor 1 that compresses air 25 supplied from the outside, a gas turbine combustor 5 that mixes and burns combustion air 26 from the compressor 1 and fuel, and combustion that is discharged from the gas turbine combustor 5. And a turbine 28 that is rotationally driven by the gas 27. The compressor 1 and the turbine 28 are connected by a single rotating shaft, and a generator 29 is also connected to the rotating shaft. Therefore, the compressor 1 and the generator 29 are driven by the rotation of the turbine 28.

  The gas turbine combustor 5 includes a combustor liner 3 inside the combustor outer cylinder 2, and combustion air 26 flows through a flow path between the combustor outer cylinder 2 and the combustor liner 3. The combustion air 26 is compressed air from the compressor 1. The upstream side of the combustor outer cylinder 2 is sealed by a closing plate 6. Here, the direction in which the combustion gas 27 flowing inside the combustor liner 3 flows is defined as the downstream direction, and the side where the air holes 9 for ejecting fuel and air are installed is defined as the upstream side.

  A plurality of burners for injecting fuel and combustion air are provided on the upstream side of the combustor liner 3. FIG. 1 shows a case where seven burners are provided, and some of the burners are shown in FIG. With such a burner arrangement, fuel can be separately supplied to each burner, and various partial load operations of the gas turbine can be handled. In the present embodiment, the central burner is referred to as a central burner, and the outer peripheral burner is referred to as an outer peripheral burner.

On the upstream side of the combustor liner 3, plate-like members 11, 10 </ b> A constituting each burner are provided.
10B, 10C, 10D, 10E, and 10F are provided, and a plurality of air holes 9 are provided in the plate-like members 11, 10A, 10B, 10C, 10D, 10E, and 10F. The seven plate members 11, 10A, 10B, 10C, 10D, 10E, and 10F are held by the holding member 12, and the plate members 11, 10A, 10B, 10C, 10D, 10E, and 10F and the holding member 12 are held. To partition the upstream side of the combustion chamber 4. The plate-like members 11, 10A, 10B, 10C, 10D, 10E, 10F and the holding member 12 may be an integral member. A fuel distributor 7 having a fuel nozzle 8 is installed on the upstream side of each plate member 11, 10 A, 10 B, 10 C, 10 D, 10 E, 10 F. The fuel distributor 7 is held by a closing plate 6. Has been. A plurality of fuel nozzles 8 are provided on the downstream side of the fuel distributor 7, and the fuel nozzles 8 are provided so as to correspond to the plurality of air holes 9. And the fuel nozzle 8 is provided with respect to the air hole 9 so that the coaxial jet flow in which the air wraps the fuel is ejected from the air hole 9 to the combustion chamber 4.

Next, the fuel supply system will be described. The fuel supplied from the fuel supply facility 16 passes through the fuel cutoff valve 17 and then branches to each burner. And the flow control valve 18,
The fuel that has passed through 19 and 20 is supplied to the central burner and the outer peripheral burner. For example, in the case of the outer peripheral burner provided with the plate-like member 10D, the fuel 21 that has passed through the flow rate control valve 18 flows down the cooling fuel supply system 13 that penetrates the closing plate 6 and is supplied to the inside of the holding member 12. It is guided to the flow path 14D. The cooling fuel channel 14D is provided as a channel suitable for cooling the holding member 12 as described later. The fuel having cooled the holding member 12 by the cooling fuel flow path 14 </ b> D again flows through the distributor supply system 15 provided so as to penetrate the closing plate 6 and is supplied to the fuel distributor 7. As described above, the fuel supply system that supplies fuel to the outer peripheral burner includes the flow rate adjusting valve 18 that adjusts the flow rate of supplying fuel to the outer peripheral burner, the cooling fuel supply system 13, the cooling fuel flow path 14D, and the distributor supply. It is comprised by the system | strain 15. The same applies to the fuel supply system in the central burner and the other peripheral burners. The burner in the present embodiment includes a fuel distributor 7 that distributes fuel to the fuel nozzle 8, a fuel nozzle 8 that injects fuel into the combustion chamber, an air hole 9 that ejects fuel and air into the combustion chamber, A plate-like member provided with the air holes 9 is provided.

  The fuel 24 supplied to the fuel distributor 7 is injected from the fuel nozzle 8 into the air hole 9 by the burner configured as described above. Also, the combustion air 26 that has flowed through the flow path between the combustor outer cylinder 2 and the combustor liner 3 reaches the closing plate 6 and is then drawn into the air hole 9. Therefore, a coaxial jet of fuel and air is injected from the air hole 9 into the combustion chamber 4 to form a flame in the combustion chamber 4 and a combustion gas 27 is generated. The combustion gas 27 passes through a combustor tail pipe communicating with the downstream of the combustion chamber 4 and is supplied to the turbine 28 described above.

  In the present embodiment, the plate-like member 11 is held by the holding member 12, and the cooling fuel channel 14 is provided inside the holding member 12, and the fuel that has flowed through the cooling fuel channel 14 is supplied to the fuel nozzle 8. Thus, since the holding member 12 is cooled using fuel, the cooling air for cooling the holding member 12 becomes unnecessary. Therefore, the air used for cooling can be used as the combustion air 26, and the amount of combustion air can be increased. Such an increase in the amount of combustion air reduces NOx emissions.

  FIG. 7 shows the NOx emission reduction effect of this embodiment. The horizontal axis of the graph of FIG. 7 represents the ratio of the fuel flow rate to the combustion air flow rate (fuel air ratio) for the fuel and combustion air supplied to the combustion chamber 4, and the vertical axis represents the NOx emission amount.

  Point P indicates the fuel-air ratio (F / A) and NOx emission when the holding member 12 is cooled with air (hereinafter referred to as a comparative example). On the other hand, in the method of cooling the holding member 12 using fuel as in this embodiment, the amount of combustion air can be increased compared to the comparative example. Therefore, the fuel-air ratio in the present embodiment is smaller than the point P, and the flame temperature is lowered. Therefore, the NOx emission amount also decreases due to the decrease in the flame temperature (point Q in the figure). As described above, the method of cooling the holding member using the fuel reduces the NOx emission amount as compared with the comparative example.

  Furthermore, the following effects are also obtained in this embodiment. Since the fuel 22 takes heat from the holding member 12 while passing through the cooling fuel flow path 14, the temperature of the fuel rises. As a result, the temperature of the fuel supplied from the air hole 9 to the combustion chamber 4 also increases. The combustion speed has the property of increasing with the temperature of the fuel and combustion air supplied to the combustion chamber 4. Therefore, when the fuel is used for cooling the holding member 12 as in the present embodiment, the combustion speed increases as compared with the comparative example. Since such an increase in the burning rate contributes to the stabilization of the flame, the effect of stabilizing the flame can also be obtained by this embodiment.

  In the present embodiment, the holding members 12 provided for holding the plate-like members 11, 10A, 10B, 10C, 10D, 10E, and 10F, and a plurality of members formed inside the holding member 12 for each burner. Cooling fuel flow paths 14, 14A, 14B, 14C, 14D, 14E, 14F, and a plurality of fuel supply systems corresponding to the burners, and the fuel from the fuel supply system is supplied to the cooling fuel flow paths 14, 14A, 14B, 14C, 14D, 14E, 14F flows and is supplied to the fuel nozzle 8.

Here, since the plate-shaped members 11, 10A, 10B, 10C, 10D, 10E, and 10F are formed with the air holes 9 and the combustion air 26 is supplied from the compressor 1, there is little need for further cooling. However, the plate-like members 11, 10A, 10B, 10C, which partition the upstream side of the combustion chamber 4,
10D, 10E, 10F and the holding member 12 are regions other than the plate-like member 11 constituting the central burner and the plate-like members 10A, 10B, 10C, 10D, 10E, 10F constituting the outer peripheral burner (that is, the holding member 12). Then, a recirculation flow region is formed downstream thereof. Due to this recirculation flow region, the high-temperature combustion gas 27 formed in the combustion chamber 4 is carried to the upstream holding member 12. Further, the holding member 12 also receives radiant heat from the combustion gas 27. As a result, since the metal temperature of the holding member 12 becomes high, it is necessary to cool the holding member 12 in order to ensure the reliability of the holding member 12.

  In this embodiment, a separate fuel supply system is provided for each burner. Therefore, the number of burners that supply fuel can be controlled by adjusting the flow rate control valves 18, 19, and 20 provided in the respective fuel supply systems in accordance with the gas turbine load.

  Specifically, in the partial load operation in the middle of raising the gas turbine load to the rating, for example, the following operation method is adopted. First, fuel is supplied to the central burner, and then fuel is supplied to the outer peripheral burner provided with the plate-like member 10A. Then, the fuel is sequentially supplied in the order of the outer peripheral burners provided with the plate-like members 10B, 10C, 10D, 10E, and 10F, thereby leading the gas turbine load to the rating. In such an operation method, while the fuel is supplied only to the central burner, the metal temperature of the holding member 12 mainly increases around the plate-like member 11 constituting the central burner. However, only the region where the metal temperature has risen can be cooled by the fuel passing through the cooling fuel channel 14.

  On the other hand, when the holding member 12 is uniformly cooled, there is a possibility that the holding member 12 around the burner to which fuel is not supplied is excessively cooled in the partial load operation in which fuel is supplied to only a part of the burners. This is because a flame is generated in the combustion chamber 4 only from the burner supplied with fuel, and no flame is generated from the burner not supplied with fuel. Therefore, in this embodiment, the fuel is provided by providing a plurality of cooling fuel flow paths 14, 14A, 14B, 14C, 14D, 14E, 14F formed for each burner and a plurality of fuel supply systems corresponding to the burners. Since the fuel does not flow through the cooling fuel flow path corresponding to the burner that is not supplied, it is possible to prevent the holding member 12 from being uniformly cooled. Then, only the holding member 12 near the burner that needs to be cooled according to the state of the partial load can be appropriately cooled.

  In FIG. 1, the holding member 12 that is an area (dead space) other than the burner is provided with the wave-like cooling fuel flow paths 14A, 14B, 14C, 14D, 14E, and 14F, but the flow path shape is limited to this. There is no need. An optimal flow path shape can be set according to conditions such as the shape of the plate-like member and the holding member 12.

  FIG. 3 is a view of the burner as viewed from the combustion chamber in the second embodiment. In the first embodiment, a separate fuel supply system is provided for each burner, but in the second embodiment, two or a plurality of burner fuel supply systems are combined into one. By reducing the number of fuel supply systems, the fuel supply system can be simplified.

  For example, as shown in FIG. 3, for six outer peripheral burners, a common cooling fuel flow path 14 </ b> G around each of plate members 10 constituting two adjacent burners, and a fuel supply system that supplies fuel to them Is provided. As a result, the number of fuel supply systems required for the six outer peripheral burners is three, and the fuel supply system can be simplified.

  4 is a view of the burner as viewed from the combustion chamber in Embodiment 3, and FIG. 5 is a longitudinal side view of the burner and the fuel supply system. The holding member 12 of Example 3 has a structure in which the cooling air hole 30 penetrating in the thickness direction is also provided in the holding member of Example 1. Therefore, since the holding member 12 is cooled by the combined use of the fuel and the cooling air 31, the cooling effect is increased.

  However, since a part of the combustion air 26 supplied from the compressor 1 is used as the cooling air 31, the amount of combustion air is reduced by that amount, but this is implemented when it is desired to enhance the cooling effect of the holding member 12. Example 3 is effective.

  FIG. 6 is a view of the burner in Example 4 as viewed from the combustion chamber. The holding member 12 of the fourth embodiment has a structure in which the cooling air hole 30 penetrating in the thickness direction is also provided in the holding member 12 of the second embodiment. Although the effect of this embodiment is basically the same as that of Embodiment 3, the fuel supply system can be simplified because the fuel supply systems to a plurality of burners are combined into one.

It is the figure which looked at the burner in Example 1 from the combustion chamber. 1 is a system diagram of a gas turbine including a longitudinal section of a combustor in Embodiment 1. FIG. It is the figure which looked at the burner in Example 2 from the combustion chamber. It is the figure which looked at the burner from Example 3 in the combustion chamber. In Example 3, it is a vertical side view of a burner and a fuel supply system part. It is the figure which looked at the burner in Example 4 from the combustion chamber. The reduction effect of the NOx emission amount by Example 1 is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Combustor outer cylinder, 3 ... Combustor liner, 4 ... Combustion chamber, 5 ... Gas turbine combustor, 6 ... Closure plate, 7 ... Fuel distributor, 8 ... Fuel nozzle, 9 ... Air hole DESCRIPTION OF SYMBOLS 10,10A, 10B, 10C, 10D, 10E, 10F, 11 ... Plate-like member, 12 ... Holding member, 13 ... Cooling fuel supply system, 14, 14A, 14B, 14C, 14D, 14E, 14F, 14G ... Cooling Fuel flow path, 15 ... distributor supply system, 16 ... fuel supply equipment, 17 ... fuel shut-off valve, 18, 19,
20 ... Flow control valve 21, 22, 23, 24 ... Fuel, 25 ... Air, 26 ... Combustion air,
27 ... Combustion gas, 28 ... Turbine, 29 ... Generator, 30 ... Cooling air hole, 31 ... Cooling air.

Claims (5)

A combustion chamber for burning fuel and combustion air; a plurality of air holes for supplying the combustion air provided in a plate-like member upstream of the combustion chamber; and the combustion air and the fuel through the air holes A combustion apparatus comprising a burner with a fuel nozzle arranged so that a coaxial jet is supplied to the combustion chamber;
While holding the plate-like member by a holding member, a cooling fuel flow path is provided inside the holding member,
A combustion apparatus for supplying fuel flowing through the cooling fuel flow path to the fuel nozzle. A combustion chamber for burning fuel and combustion air; a plurality of air holes for supplying the combustion air provided in a plate-like member upstream of the combustion chamber; and the combustion air and the fuel through the air holes A combustion apparatus comprising a plurality of burners each having a fuel nozzle disposed so that a coaxial jet is supplied to the combustion chamber;
A holding member provided to hold the plate-like member;
A plurality of cooling fuel passages formed inside the holding member for each of the burners;
A plurality of fuel supply systems corresponding to the burner,
A combustion apparatus, wherein fuel from the fuel supply system flows through the cooling fuel flow path of the holding member and is supplied to the fuel nozzle. A combustion chamber for burning fuel and combustion air; a plurality of air holes for supplying the combustion air provided in a plate-like member upstream of the combustion chamber; and the combustion air and the fuel through the air holes A combustion apparatus comprising a plurality of burners each having a fuel nozzle disposed so that a coaxial jet is supplied to the combustion chamber;
A holding member provided to hold the plate-like member;
A plurality of fuel flow paths formed inside the holding member for each of the burners;
A plurality of fuel supply systems corresponding to the burners;
When the gas turbine is in partial load operation, the combustion apparatus is characterized in that fuel from a part of the fuel supply system flows through the fuel flow path of the holding member and is supplied to the fuel nozzle.   4. The combustion apparatus according to claim 1, further comprising a cooling hole penetrating in the thickness direction of the holding member. A fuel supply method for a combustion apparatus comprising a burner for supplying a coaxial jet of combustion air and fuel from a plate-like member provided upstream of a combustion chamber for burning fuel and combustion air,
A fuel supply method for a combustion apparatus, comprising: supplying fuel to the combustion chamber after the fuel flows into a cooling fuel flow path provided inside a holding member that holds the plate-like member.

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