JP2008038807A - Gas turbine and transition piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas turbine and a transition piece capable of lowering costs and improving performance of the gas turbine by decreasing the tip clearance. <P>SOLUTION: In the gas turbine equipped with a compressor 1 for generating compressed air, a combustor 3 for burning fuel with compressed air from the compressor 1 and generating combustion gas, and a turbine 4 rotationally driven by the combustion gas from the combustor 3, a heat exchanger 22 arranged on a transition piece 15 introducing the combustion gas from the combustor 3 to the turbine 4 and heating a part of the compressed air extracted from the compressor 1 by the combustion gas and a casing passage 23 which is formed on a casing 16 of the turbine 4 and through which the air heated by the heat exchanger 22 flows in are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas turbine that obtains rotational power using combustion gas obtained by burning compressed air and fuel, and more particularly, to a gas turbine and a transition piece that are suitable for adjusting casing temperature.

  Regarding the reliability of the gas turbine, in addition to the strength such as creep, fatigue and corrosion, the problem of deformation is also important. In particular, the radial deformation of the turbine during operation must be considered so that the rotating part (the rotor with the moving blades) and the stationary part (the casing with the blade ring facing the moving blades) do not come into contact with each other. Don't be. When the rotating part and the stationary part of the turbine come into contact with each other, the rotor blades and the blade ring are damaged to deteriorate the performance of the turbine. In the worst case, the turbine cannot be operated. On the other hand, when the gap (tip clearance) between the moving blade and the blade ring is wide, the combustion gas passing through this portion does not contribute to the driving of the turbine, so that the efficiency is lowered. Therefore, development of turbine clearance control is underway for the purpose of operating gas turbines safely and with high efficiency.

  As an example of turbine clearance control, a configuration in which steam from a steam supply source (for example, an auxiliary boiler or a steam turbine bottoming system) flows through a cooling passage in a blade ring is disclosed (for example, see Patent Document 1). In this conventional technology, the steam from the auxiliary boiler is supplied to the cooling passage in the blade ring at startup, and the blade ring in the cold state is heated at startup, so the clearance is expanded and contact at the minimum clearance at startup is avoided. It is supposed to be. Further, during normal operation, steam from the bottoming system of the steam turbine is supplied to the cooling passage in the blade ring so that the clearance is appropriately adjusted to suppress the performance degradation of the gas turbine.

JP 2001-248406 A

However, there are the following problems in the above-described prior art.
That is, in the above prior art, the steam from the auxiliary boiler is supplied to the cooling passage in the blade ring at the time of startup to heat the blade ring. For this reason, it is necessary to provide equipment such as an auxiliary boiler for generating steam, and it is necessary to use a material with improved corrosion resistance for the portion where the steam is introduced, which may increase the cost.

  An object of the present invention is to provide a gas turbine and a transition piece that can improve the performance of the gas turbine by reducing the tip clearance while reducing the cost.

  (1) In order to achieve the above object, the present invention includes a compressor that generates compressed air, a combustor that generates combustion gas by burning fuel together with the compressed air from the compressor, and the combustor. A gas turbine having a turbine that is driven to rotate by the combustion gas of the combustion chamber, provided in a transition piece that guides the combustion gas from the combustor to the turbine, and a part of the compressed air extracted from the compressor as the combustion gas. A heat exchange means for heating and a casing flow path formed in the casing of the turbine and into which the air heated by the heat exchange means flows.

  In the present invention, a heat exchange means for heating a part of the compressed air extracted from the compressor with the combustion gas is provided in the transition piece for introducing the combustion gas from the combustor to the turbine. For example, when the gas turbine is started, the air heated by the heat exchange means is caused to flow into the casing flow path of the turbine. This heats the casing, which has a larger heat capacity and a slower response to temperature rise than the rotor of the turbine, thereby reducing the temporary drop in the gap (tip clearance) between the blade ring of the casing and the rotor blade facing the rotor. be able to. Thereby, the design value of the chip clearance (in other words, the value when the rotor and the casing are not thermally deformed) can be reduced, and the clearance during operation can be reduced. In addition, unlike the case where steam is supplied to the casing flow path, for example, there is no need for a facility for generating steam, and it is not necessary to use a material with improved corrosion resistance for parts such as the casing flow path. Can be planned. As described above, in the present invention, the cost of the gas turbine can be improved by reducing the tip clearance while reducing the cost.

  (2) In the above (1), preferably, the heat exchanging means is connected to the first manifold into which a part of the compressed air extracted from the compressor flows, and the first manifold, respectively. A plurality of heat transfer tubes provided along the circumferential direction of the tube wall and a second manifold connected to the downstream side of the plurality of heat transfer tubes.

  (3) In the above (1) or (2), preferably, the air that has flowed into the casing flow path is caused to flow out to the gas flow path in the turbine.

  (4) In any one of the above (1) to (3), preferably, air temperature adjusting means for adjusting the temperature of the air flowing into the casing flow path is provided.

  (5) In the above (4), preferably, the air temperature adjusting means bypasses the heat exchanging means, and bypass piping for supplying a part of the compressed air extracted from the compressor to the casing flow path; A flow rate control valve provided in the bypass pipe, temperature detection means for detecting the temperature of the casing, and the opening degree of the flow rate control valve is controlled so that the temperature of the casing detected by the temperature detection means approaches a target temperature. And valve control means.

  (6) In said (5), the said valve control means sets the target temperature of the said casing according to the fuel flow volume supplied to the said combustor, or the rotation speed of the rotor of the said turbine.

  (7) To achieve the above object, the present invention relates to a compressor that generates compressed air, a combustor that generates combustion gas by combusting compressed air and fuel from the compressor, and the combustor. Heat that is provided in a gas turbine including a turbine that is rotationally driven by combustion gas, and heats part of the compressed air extracted from the compressor with the combustion gas in a transition piece that guides the combustion gas from the combustor to the turbine. Exchange means are provided.

  (8) In the above (7), preferably, the heat exchanging means is connected to the first manifold into which a part of the compressed air extracted from the compressor flows, and to the first manifold, respectively. A plurality of heat transfer tubes provided along the circumferential direction of the tube wall and a second manifold connected to the downstream side of the plurality of heat transfer tubes.

  According to the present invention, it is possible to improve the performance of the gas turbine by reducing the tip clearance while reducing the cost.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a system flow diagram illustrating the overall configuration of the gas turbine according to the present embodiment, and FIG. 2 is a partial cross-sectional view illustrating the detailed structure of the main part of the gas turbine according to the present embodiment.

  1 and 2, the gas turbine combusts the fuel supplied through the fuel flow control valve 2 together with the compressor 1 for compressing air and the compressed air generated by the compressor 1 to produce combustion gas. A combustor 3 to be generated and a turbine 4 driven by high-temperature and high-pressure combustion gas from the combustor 3 are provided. Further, the rotor 5 of the turbine 4 and the rotor 6 of the compressor 1 are connected by an intermediate shaft 7, and the rotor 6 and the generator 8 of the compressor 1 are connected by a connecting shaft 9, and the generator 8 is connected to the turbine 4. The rotational power of the rotor 5 is converted into electric energy.

  The compressor 1 includes a rotor 6 and a substantially cylindrical casing 10 that covers an outer peripheral side (the upper side in FIG. 2) of the rotor 6. The rotor 6 is configured by laminating a disk 12 having a plurality of moving blades 11 arranged in the circumferential direction on the outer circumferential side in the axial direction (left-right direction in FIG. 2). On the inner peripheral side (lower side in FIG. 2) of the casing 10, a plurality of stationary blades 13 arranged in the circumferential direction are provided in a plurality of stages in the axial direction. The moving blades 11 and the stationary blades 13 are alternately arranged in the axial direction so as to compress air.

  A plurality of the combustors 3 are provided at substantially equal intervals around the compressor 1, and each includes a combustion device 14 and a transition piece 15 provided on the downstream side (right side in FIG. 2) of the combustion device 14. ing. The combustion device 14 burns fuel together with the compressed air from the compressor 1, and the combustion gas is supplied to the turbine 4 via the transition piece 15.

  The turbine 4 includes the rotor 5 and a substantially cylindrical casing 16 that covers the outer peripheral side of the rotor 5. The rotor 5 is a disk having a plurality of moving blades (in this embodiment, the first-stage moving blade 17A, the second-stage moving blade 17B, or the third-stage moving blade 17C) arranged on the outer circumferential side in the circumferential direction. 18 and hollow spacers 19 are alternately stacked in the axial direction. A plurality of blade rings 20 are provided on the inner peripheral side of the casing 16 so as to face the plurality of blades 17 </ b> A to 17 </ b> C, respectively. In the embodiment, the first stage stationary blade 21A, the second stage stationary blade 21B, and the third stage stationary blade 21C) are engaged and supported. And the stationary blades 21A-21C accelerate the combustion gas from the combustor 3, and the rotor 5 provided with the moving blades 17A-17C rotates.

  Here, as a major feature of the present embodiment, the transition piece 15 of the combustor 3 is provided with a heat exchanging portion 22 (heat exchanging means) that heats a part of the compressed air extracted from the compressor 1 with combustion gas. A plurality of casing flow paths 23 into which the air heated by the heat exchanging portions 22 of the plurality of transition pieces 15 respectively flows are formed on the outer peripheral side of the casing 16 of the turbine 4. Details will be described below.

  FIG. 3 is a partially enlarged perspective view showing the detailed structure of the heat exchanging portion 22 of the transition piece 15, and FIG. 4 is a partially enlarged perspective view of the casing 16 of the turbine 4 showing the detailed structure of the casing flow path 23. is there.

  3 and FIG. 4 and FIG. 2 described above, the heat exchanging portion 22 of the transition piece 15 is provided on the radially inner side of the turbine 4 on the outer peripheral side of the transition piece 15 (the lower side in FIG. 2 and FIG. 3). A first manifold 24 having an inlet (not shown) for extracting a part of the compressed air generated by the compressor 1, and connected to the first manifold 24, respectively, along the circumferential direction of the tube wall of the transition piece 15. A plurality of heat transfer tubes 25 provided on the outer peripheral side of the transition piece 15 in the radial direction outside (upper side in FIGS. 2 and 3) and connected to the downstream side of the plurality of heat transfer tubes 25. 2 manifolds 26. The air flowing in the first manifold 24, the heat transfer tube 25, and the second manifold 26 is heated by exchanging heat with the combustion gas flowing in the transition piece 15.

  The casing 16 of the turbine 4 has, for example, a half-crack structure, and there is a gap at a position corresponding to the first stage stationary blade 21A, the first stage moving blade 17A, and the second stage stationary blade 21B. The casing 27 is joined so as to cover the outer peripheral side via the. In addition, a plurality of partition walls 28 that divide the gap between the casings 16 and 27 in the circumferential direction are joined together, whereby a plurality of axial passages (left and right direction in FIG. 2, lower left and upper right direction in FIG. 4) casing flow paths 23 are formed. Is formed. Further, the casing 16 has an inflow hole 29 opened on the upstream side in the axial direction of the casing flow path 23 (left side in FIG. 2, lower left side in FIG. 4), and the downstream side in the axial direction of the casing flow path 23 (right side in FIG. 2). , And an outflow hole 31 communicating with the chamber 30 on the outer peripheral side of the second stage stationary blade 21B, for example, is formed. A pipe 32 is provided to connect the second manifold 26 of the heat exchanging section 22 of the transition piece 15 and the inflow hole 29 of the casing 16, and the air heated by the heat exchanging section 22 through the pipe 32 is the casing flow path 23. To flow into. Further, the air that has flowed through the casing flow path 23 flows out into the chamber 30 through the discharge hole 31 of the casing 16, and finally flows out into the gas flow path (gas path) in the turbine 4.

  Next, the effect of this embodiment is demonstrated. FIG. 5 shows changes over time in the temperature Tr of the rotor 5 of the turbine 4 and the temperature Tc2 of the casing 16 at the time of start-up, tip clearance (specifically, the blade ring 20 of the casing 16 facing the rotor blades 17A to 17C of the rotor 5 respectively. It is a figure showing a time-dependent change of a gap | interval). In FIG. 5, the alternate long and short dash line shows, as a comparative example, changes over time in the temperature Tc1 of the casing 16 and the tip clearance when the casing 16 of the turbine 4 is not preheated at the time of startup.

  For example, when the casing 16 of the turbine 4 is not preheated at the time of start-up, the casing 16 has a larger heat capacity than the rotor 5, so that the temperature Tc1 of the casing 16 has a slower response than the temperature Tr of the rotor 5 and is settled. Takes time. Therefore, when start-up is started at time t0 (in other words, when the flow rate of fuel supplied to the combustor 3 is increased and the temperature of the combustion gas rises), the temperature Tr of the rotor 5 first rises and the rotor 5 extends radially outward. The tip clearance, for example, falls from the set value X0 (in other words, the value when the rotor 5 and the casing 16 are not thermally deformed) to the minimum value Xmin1. Thereafter, the temperature Tc1 of the casing 16 rises with a delay, the casing 16 extends radially outward, and the tip clearance is restored to, for example, the steady value Xt.

  On the other hand, when the casing 16 is heated by flowing the air heated by the heat exchanging portion 22 of the transition piece 15 through the casing flow path 23 as in the present embodiment, the temperature Tr of the rotor 5 and the temperature Tc2 of the casing 16 are substantially equal. At the same time start to rise. Therefore, since the radially outward expansion of the rotor 5 and the casing 16 proceeds almost simultaneously, the tip clearance decreases from the design value X0 to the minimum value Xmin2 (where Xmin2 <Xmin1), and then recovers to the steady value Xt. To do. In other words, in the present embodiment, for example, compared with a case where the casing 16 of the turbine 4 is not preheated at the time of start-up, the temporary decrease width of the tip clearance can be reduced. Accordingly, as shown in FIG. 7, for example, the set value can be narrowed from Xo to Xo ′ so that the minimum value of the tip clearance becomes Xmin1, and accordingly, the steady value also decreases from Xt to Xt ′. Turbine efficiency can be improved. Specifically, for example, when the present invention is applied to a conventional gas turbine in which the clearance design value X0 = 100% (when the rotor 5 is stationary 100%) and the steady value Xt = 50%, the clearance design It is possible to reduce the value X0 '= 80% and the steady value Xt' = 27%, thereby improving the overall efficiency of the gas turbine.

  Moreover, in this embodiment, the thermal energy of the combustion gas of the combustor 3 at the time of starting can be collect | recovered by providing the heat exchange part 22 of the transition piece 15. FIG. FIG. 7 shows the air inlet temperature T_Ain and the air outlet temperature T_Aout of the heat exchanging part 22 and the temperature Tc of the casing 16 of the turbine 4 as the combustion gas inlet temperature T_Gin of the heat exchanging part 22 of the transition piece 15 at start-up changes with time. It is a figure showing the time-dependent change of as an example.

  As shown in FIG. 7, normally, at the start of startup (time t0 to t1), the flow rate of fuel supplied to the combustor 3 is relatively increased in order to speed up the start-up of the drive of the turbine 4. The temperature rises rapidly. Thereafter, when the rotational speed of the rotor 5 of the turbine 4 reaches the rated rotational speed (time t1), for example, in order to perform a warm-up operation for stabilizing the temperature of the lubricating oil, the flow rate of the fuel supplied to the combustor 3 is temporarily reduced. And maintaining it, the temperature of the combustion gas decreases and stabilizes. When the warm-up operation ends (time t2), the generator 9 is connected to the connecting shaft 8 to start power generation, and the fuel flow rate supplied to the combustor 3 is increased, so that the temperature of the combustion gas gradually increases. To do. Thereafter, when the power generation output reaches the rated output (time t3), although not shown, for example, the fuel flow rate supplied to the combustor 3 is maintained at a constant flow rate, so that the temperature of the combustion gas is stabilized.

  As described above, the temperature of the combustion gas at the start of activation (time t0 to t1) is rapidly increased, and it is usually difficult to say that all of the heat energy is effectively utilized. In the present embodiment, the heat exchanging part 22 of the transition piece 15 heats a part of the compressed air extracted from the compressor 1 by the combustion gas at the start of startup, so a part of the thermal energy of the combustion gas at the start of startup. Can be recovered. Moreover, since the air heated by the heat exchange part 22 of the transition piece 15 flows into the casing flow path 23 of the turbine 4 and heats the casing 16 of the turbine 4 that is cooled at the start of startup, it can be used effectively.

  Further, in the present embodiment, unlike the case where steam is introduced, for example, it takes time to generate steam, so that the startup time of the gas turbine does not become long. In addition, no equipment for generating steam is required, and it is not necessary to use a material with improved corrosion resistance for the part where steam is introduced, so that the cost can be reduced. Therefore, in the present embodiment, it is possible to improve the performance of the gas turbine by reducing the tip clearance while reducing the cost.

  In the above embodiment, the heat exchanging portion 22 of the transition piece 15 has been described by taking as an example a structure having a plurality of heat transfer tubes 25 provided along the circumferential direction of the tube wall of the transition piece 15. Not limited. That is, for example, a heat transfer tube may be provided inside the transition piece 15, or a plate heat exchanger may be provided instead of the heat transfer tube, for example. Further, for example, ribs and fins may be provided for the purpose of expanding the heat transfer area. In these cases, the same effect as described above can be obtained.

  In the above-described embodiment, the case where the casing 27 is joined to cover the outer peripheral side of the casing 16 of the turbine 4 to form the casing flow path 23 has been described as an example. That is, for example, a casing channel may be formed in the casing 16, and for example, a rib or a fin may be provided in order to increase the heat transfer area. Further, for example, considering the material and structure of the casing 16, a pipe for heating the flange portion 16a of the casing 16 (see FIG. 4 described above) may be provided, and this may be used as the casing flow path. In these cases, the same effect as described above can be obtained.

  Another embodiment of the present invention will be described with reference to FIGS. The present embodiment is an embodiment in which an air temperature adjusting means for adjusting the air temperature supplied to the casing flow path 23 of the turbine 4 is provided.

  FIG. 8 is a schematic diagram illustrating the overall configuration of the gas turbine according to the present embodiment. In FIG. 8, parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  In the present embodiment, a bypass pipe 33 that supplies a part of the compressed air extracted from the compressor 1 to the casing flow path 23 of the turbine 4 and an air flow rate control valve 34 provided in the bypass pipe 33 (instead of this) A casing temperature detector 35 (temperature detection means) for detecting the temperature of the casing 16 of the turbine 4, a detection signal from the casing temperature detector 35, and a fuel flow rate from the gas turbine control device 36. A casing temperature control device 37 (valve control means) to which a fuel flow rate command signal output to the control valve 2 is input is provided. The gas turbine control device 36 performs predetermined arithmetic processing on a detection signal from a detector (not shown) that detects, for example, the output command value MWD of the gas turbine and the rotational speed N of the rotor 5, and generates the generated fuel. A flow rate command signal is output.

  The casing temperature control device 37 sets the target temperature of the casing 16 of the turbine 4 according to the fuel flow rate command value FFD (in other words, load fluctuation of the gas turbine) input from the gas turbine control device 36. . Then, the opening degree Cv of the air flow control valve 34 is calculated by PID control so that the temperature of the casing 16 detected by the casing temperature detector 35 approaches the target temperature, and the generated drive signal is output to the air flow control valve 34. It is supposed to be. More specifically, the casing temperature control device 37 is set so that the target temperature of the casing 16 increases as the fuel flow rate command value FFD increases (in other words, the load of the gas turbine increases), for example. In order to bring the temperature closer, the opening Cv of the air flow control valve 34 is controlled to be small. As a result, the flow rate of air supplied to the casing flow path 23 via the bypass pipe 33 is reduced, and the temperature of the air supplied to the casing flow path 23 is increased. Further, for example, the target flow rate of the casing 16 is set to be lower in accordance with the decrease in the fuel flow rate command value FFD (in other words, the load decrease of the gas turbine), and the air flow rate control valve is set to bring the temperature of the casing 16 closer to this target temperature. The opening degree Cv of 34 is controlled to be increased. As a result, the flow rate of air supplied to the casing passage 23 via the bypass pipe 33 is increased, and the temperature of the air supplied to the casing passage 23 is lowered.

  Also in the present embodiment configured as described above, the performance of the gas turbine can be improved by reducing the tip clearance while reducing the cost, as in the case of the first embodiment. In the present embodiment, the thermal expansion of the casing 16 of the turbine 4 is managed by adjusting the temperature of the air flowing into the casing flow path 23 of the turbine 4 according to the load fluctuation of the gas turbine, so that the optimum turbine efficiency is achieved. Can be achieved. The details will be described with reference to FIG.

  FIG. 9 shows the change over time in the degree of opening Cv of the air flow control valve 34 that is controlled in response to the change over time in the fuel flow rate command value FFD at the time of stop, the temperature Tr of the rotor 5 of the turbine 4 and the temperature of the casing 16 associated therewith. It is a figure showing the time-dependent change of Tc2, and the time-dependent change of chip clearance. In FIG. 9, the alternate long and short dash line indicates, as a comparative example, changes over time in the temperature Tc1 of the casing 16 and the tip clearance when the casing 16 of the turbine 4 is not cooled.

  In FIG. 9, for example, when the casing 16 of the turbine 4 is not cooled at the time of stoppage, the casing 16 has a larger heat capacity than the rotor 5, so that the temperature Tc1 of the casing 16 has a slower response than the temperature Tr of the rotor 5. It takes time to settle down. Therefore, when the load of the gas turbine decreases at time t4 (in other words, when the fuel flow rate command value FFD decreases and the temperature of the combustion gas decreases), the temperature Tr of the rotor 5 first decreases and the rotor 5 moves radially inward. The chip clearance is shortened, and the tip clearance increases, for example, from the steady value Xt to the maximum value Xmax1. Thereafter, the temperature Tc1 of the casing 16 descends with a delay, the casing 16 contracts radially inward, and the tip clearance is restored to, for example, the design value Xt.

  On the other hand, as in the present embodiment, the opening Cv of the air flow rate control valve 34 is increased in accordance with the decrease in the fuel flow rate command value FFD, and the temperature of the air flowing through the casing flow path 23 of the turbine 4 is lowered. Is cooled, the temperature Tr of the rotor 5 and the temperature Tc2 of the casing 16 start decreasing almost simultaneously. For this reason, since the reduction of the rotor 5 and the casing 16 toward the radially inner side proceeds almost simultaneously, the tip clearance increases from the steady value Xt to the design value X0, for example. That is, in this embodiment, compared with the case where the casing 16 of the turbine 4 is not cooled at the time of a stop, for example, the temporary rise width of a tip clearance can be made small and turbine efficiency can be improved.

  In the other embodiment, the casing temperature control device 37 has been described by taking as an example the case where the target temperature of the casing 16 of the turbine 4 is set according to the fuel flow rate command value FFD input from the gas turbine control device 36. However, it is not limited to this. That is, for example, the target temperature of the casing 16 of the turbine 4 may be set according to a detection signal from a detector that detects the number of rotations of the rotor 5 of the turbine 4. In this case, the same effect as described above can be obtained.

  Moreover, in the said embodiment, although demonstrated about the structure which heats only the casing 16 of the turbine 4 with the air heated by the heat exchange part 22 of the transition piece 15, it is not restricted to this. That is, for example, the fuel supplied to the combustor 3 may be heated. FIG. 10 is a schematic diagram showing the overall configuration of a gas turbine according to such a modification. In FIG. 10, the same parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the present modification, a heat exchanger 38 that is provided upstream of the fuel flow control valve 2 and heats the fuel supplied to the combustor 3, and between the heat exchanger 38 and the heat exchanging portion 22 of the transition piece 15. A connected pipe 39, a pipe 40 connected between the heat exchanger 38 and the casing flow path 23, and a bypass pipe 41 connected between the pipes 39, 40 so as to bypass the heat exchanger 38. A switching damper 42 that is provided at a connection portion of the bypass pipe 41 in the pipe 39 and switches one of the pipe 39 to the heat exchanger 38 side and the bypass pipe 41 side to the open state and the other to the closed state, and gas turbine control A control device 43 that performs predetermined arithmetic processing according to a fuel flow rate command signal from the device 36 and drives and controls the switching damper 42 is provided.

  The control device 43 drives and controls the switching damper 42 when the gas turbine is started, for example, to close the heat exchanger 38 side of the pipe 39 and open the bypass pipe 41 side. Thereby, the air heated by the heat exchanging part 22 of the transition piece 15 flows into the casing flow path 23 of the turbine 4 through the bypass pipe 41 and the like. Therefore, as in the case of the above-described embodiment, the temporary decrease width of the tip clearance can be reduced, whereby the design value and steady value of the tip clearance can be reduced, and the turbine efficiency can be improved. Further, the control device 43 drives and controls the switching damper 42 during rated operation, for example, to close the bypass pipe 41 side and open the heat exchanger 38 side of the pipe 39. As a result, the air heated in the heat exchange section 22 of the transition piece 15 flows into the heat exchanger 38 via the pipe 39 to heat the fuel, and the air used in the heat exchanger 38 passes through the pipe 40 to the turbine 4. Flow into the casing flow path 23. Thereby, a part of thermal energy of combustion gas can be utilized for heating of fuel, and the total efficiency of a gas turbine can be improved.

It is the schematic showing the whole structure of 1st Embodiment of the gas turbine of this invention. It is a fragmentary sectional view showing the detailed structure of the principal part of 1st Embodiment of the gas turbine of this invention. It is a partial expansion perspective view showing the detailed structure of the heat exchange part of the transition piece which comprises 1st Embodiment of the gas turbine of this invention. It is a partial expansion perspective view of the casing of the turbine showing the detailed structure of the casing channel which constitutes a 1st embodiment of the gas turbine of the present invention. It is a figure showing the time-dependent change of the temperature of the rotor of a turbine and the temperature of a casing at the time of starting, and the time-dependent change of a tip clearance. It is a figure showing the time-dependent change of the tip clearance of a turbine. It is a figure showing as an example the time-dependent change of the air inlet temperature of the heat exchange part of the transition piece and the air outlet temperature accompanying the time-dependent change of the temperature of the combustion gas of the combustor at the time of starting. It is the schematic showing the whole structure of 2nd Embodiment of the gas turbine of this invention. This represents the change over time in the opening of the air flow control valve that is controlled in response to the change over time in the fuel flow command value at the time of stoppage, the change over time in the turbine rotor temperature and casing temperature, and the change over time in the tip clearance. FIG. It is the schematic showing the whole structure of the modification of the gas turbine of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 3 Combustor 4 Turbine 5 Rotor 15 Transition piece 16 Casing 22 Heat exchanger (heat exchange means)
23 Casing channel 24 First manifold 25 Heat transfer tube 26 Second manifold 33 Bypass piping (air temperature adjusting means)
34 Air flow control valve (air temperature adjusting means)
35 Temperature detector (temperature detection means, air temperature adjustment means)
37 Casing temperature control device (control means, air temperature adjustment means)

Claims (8)

A gas turbine comprising: a compressor that generates compressed air; a combustor that burns fuel together with the compressed air from the compressor to generate combustion gas; and a turbine that is rotationally driven by the combustion gas from the combustor. ,
A heat exchange means that is provided in a transition piece that guides combustion gas from the combustor to the turbine, and heats a part of the compressed air extracted from the compressor with the combustion gas;
A gas turbine comprising: a casing passage formed in a casing of the turbine and into which air heated by the heat exchange means flows.   2. The gas turbine according to claim 1, wherein the heat exchanging means is connected to a first manifold into which a part of the compressed air extracted from the compressor flows, and to the first manifold, respectively. A gas turbine comprising: a plurality of heat transfer tubes provided along a circumferential direction; and a second manifold connected to a downstream side of the plurality of heat transfer tubes.   The gas turbine according to claim 1 or 2, wherein the air that has flowed into the casing flow path is caused to flow out to a gas flow path in the turbine.   The gas turbine according to any one of claims 1 to 3, further comprising an air temperature adjusting means for adjusting a temperature of air flowing into the casing flow path.   5. The gas turbine according to claim 4, wherein the air temperature adjusting unit bypasses the heat exchange unit and supplies a part of the compressed air extracted from the compressor to the casing flow path, and the bypass pipe. A flow rate control valve provided in the control unit, temperature detection means for detecting the temperature of the casing, and valve control for controlling the opening of the flow rate control valve so that the temperature of the casing detected by the temperature detection means approaches a target temperature. And a gas turbine.   6. The gas turbine according to claim 5, wherein the valve control means sets a target temperature of the casing in accordance with a flow rate of fuel supplied to the combustor or a rotational speed of a rotor of the turbine. Provided in a gas turbine comprising a compressor that generates compressed air, a combustor that generates combustion gas by burning compressed air and fuel from the compressor, and a turbine that is rotationally driven by the combustion gas from the combustor. , In a transition piece that directs combustion gas from the combustor to the turbine,
A transition piece comprising heat exchange means for heating a part of compressed air extracted from the compressor with the combustion gas.   8. The transition piece according to claim 7, wherein the heat exchanging means is connected to a first manifold into which a part of compressed air extracted from the compressor flows, and to the first manifold, respectively. A transition piece comprising: a plurality of heat transfer tubes provided along a circumferential direction; and a second manifold connected to a downstream side of the plurality of heat transfer tubes.

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