INTAKE AIR HEATING SYSTEM, OPERATING PROCEDURES FOR INTAKE AIR HEATING SYSTEM AND GAS TURBINE SYSTEM

Abstract

An intake air heating system is an intake air heating system configured to heat outside air flowing through an intake flow path communicating with a gas turbine compressor, the intake air heating system comprising a first heating unit which includes a return flow path for returning a portion of compressed air discharged from the compressor to the intake flow path, a second heating unit which includes a heater configured to heat the outside air by using a heat source different from the compressed air, and a control device configured to control the second heating unit so that the outside air is heated by the heater during a high-load section where a gas turbine load is higher than a first specified load.

Description

Technical area

[0001] The present disclosure relates to an intake air heating system, an operating method for an intake air heating system, and a gas turbine system.

[0002] This application claims priority based on Japanese Patent Application No. 2022-127617 filed in Japan on August 10, 2022, the contents of which are incorporated herein by reference. State of the art

[0003] In the prior art, an intake air heating system that heats outside air supplied to a compressor of a gas turbine is known. For example, a heating unit of a gas turbine disclosed in PTL 1 is configured to heat outside air by using compressed air as a heat source. The heating unit includes a return line for returning a portion of the compressed air discharged from the compressor to an intake passage. The outside air is heated by mixing the compressed air flowing through the return line with the outside air flowing through the intake passage. Citation listPatent literature

[0004] [PTL 1] Japanese Unexamined Patent Application Publication No. 2000-097046 Summary of the inventionTechnical problem

[0005] In gas turbines, there are concerns that the operating efficiency of the gas turbine may be reduced when the heating unit performs heating. This is partly because the flow rate of combustion gas supplied to the turbine is reduced by the amount of a portion of the compressed air discharged from the compressor, with the compressed air being recirculated to the intake duct.

[0006] An object of the present disclosure is to provide an intake air heating system, an operating method for an intake air heating system, and a gas turbine system that improve operating efficiency of a gas turbine. Solution to the problem

[0007] An intake air heating system according to at least one embodiment of the present disclosure is an intake air heating system configured to heat outside air flowing through an intake flow path communicating with a compressor of a gas turbine, the intake air heating system comprising: a first heating unit including a return flow path for returning a portion of compressed air discharged from the compressor to the intake flow path; a second heating unit including a heater configured to heat the outside air by using a heat source other than the compressed air; and a control device configured to control the second heating unit so that the outside air is heated by the heater in a high load section in which a gas turbine load is higher than a first specified load.

[0008] An operating method for an intake air heating system according to at least one embodiment of the present disclosure is an operating method for an intake air heating system configured to heat outside air flowing through an intake flow path communicating with a compressor of a gas turbine, where the intake air heating system includes: a first heating unit including a return flow path for returning a portion of compressed air discharged from the compressor to the intake flow path, and a second heating unit including a heater configured to heat the outside air by using a heat source other than the compressed air, and the operating method comprises: a second heating unit control step of controlling the second heating unit so that the outside air is heated by the heater in a high load section in which a gas turbine load is higher than a first specified load.

[0009] A gas turbine system according to at least one embodiment of the present disclosure includes the intake air heating system and the gas turbine. Advantageous effects of the invention

[0010] According to the present disclosure, it is possible to provide an intake air heating system, an operating method for an intake air heating system, and a gas turbine system that improve operating efficiency of a gas turbine. Brief description of the drawings Fig. 1 is a schematic view of a gas turbine system according to an embodiment. Fig. 2 is a schematic graph showing a load portion of a heating operation of a second heating unit according to an embodiment. Fig. 3 is a schematic graph showing load sections of a heating operation of a first heating unit according to an embodiment. Fig. 4 is a schematic view showing a second heating unit according to an embodiment. Fig. 5 is a schematic graph showing a heating ratio of a first heating unit and a second heating unit according to an embodiment. Fig. 6 is a schematic view showing details of a gas turbine according to an embodiment. Fig. 7 is a flowchart illustrating an operating method for an intake air heating system according to an embodiment. Description of embodiments

[0011] Some embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of components described as the embodiments or illustrated in the drawings are not intended to limit the scope of the present disclosure and are merely examples for describing the present disclosure.

[0012] For example, expressions representing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "perpendicular," "center," "concentric," or "coaxial," represent not only strictly the arrangements, but also a state of relative displacement with a tolerance or by an angle or distance, as long as the same function can be obtained.

[0013] For example, expressions that represent things being in a same state, such as “identical,” “equal,” and “homogeneous,” represent not only a strictly equal state, but also a state in which there is a tolerance or difference as far as the same function can be maintained.

[0014] For example, expressions representing shapes such as a quadrangular shape and a cylindrical shape represent not only shapes such as a quadrangular shape and a cylindrical shape in a geometrically strict sense, but also shapes including an uneven portion, a chamfer portion, or the like within a range where the same effect can be obtained.

[0015] However, expressions such as “provided with,” “containing,” or “having” a component are not exclusionary expressions that exclude the existence of other components.

[0016] The same configurations are denoted by the same reference numerals, and the description thereof may be omitted. <Overview of Gas Turbine System 1>

[0017] Fig. 1 is a schematic view of a gas turbine system 1 according to an embodiment of the present disclosure. A gas turbine 3 constituting the gas turbine system 1 includes a compressor 7, a combustor 8 that generates mixed fuel from compressed air and fuel generated by the compressor 7, and a turbine 30 driven by combustion gas discharged from the combustion chamber 8. The compressor 7 is configured to start rotation by means of a starting device 4. The fuel supplied to the combustion chamber 8 is, for example, gas fuel, but may be liquid fuel. The turbine 30 of the present example is configured to drive a generator 6 by using combustion gas discharged from the combustion chamber 8 as a power source. Exhaust gas discharged from the turbine 30 flows through an exhaust passage 39.

[0018] The compressor 7 communicates with an intake flow path 9. Outside air flowing through the intake flow path 9 is directed to the compressor 7 to generate compressed air. The gas turbine system 1 of the present disclosure includes an intake air heating system 5 configured to heat outside air flowing through the intake flow path 9, and the intake air heating system 5 includes a first heating unit 10 and a second heating unit 20. The first heating unit 10 is configured to heat outside air by using compressed air discharged from the compressor 7 as a heat source. More specifically, the first heating unit 10 includes a return flow path 15 for returning a portion of the compressed air discharged from the compressor 7 to the intake flow path 9. The outside air is heated by mixing the compressed air returned from the return flow path 15 to the intake flow path 9 with the outside air.

[0019] The Fig. The intake flow path 9 shown in FIG. 1 includes a suction chamber 90 and a suction duct 95 communicating with the suction chamber 90 and the compressor 7, and the return flow path 15 communicates with a discharge pipe 99 housed in the suction chamber 90. The compressed air flowing from the return flow path 15 into the discharge pipe 99 is discharged into the suction chamber 90 from a nozzle provided in the discharge pipe 99. The discharge pipe 99 of the present example is arranged between a suction filter 94 housed in the suction chamber 90 and an outlet 93 of the suction chamber 90.

[0020] The second heating unit 20 includes a heater 24 configured to heat the outside air using a heat source different from the compressor 7. A heat source of the heater 24 may be heat recovered from exhaust gas discharged from the turbine 30 (details will be described later) or may be heat obtained from a heat-generating body that generates heat by supplying electric power. Fig. The heater 24 shown in Figure 1 is housed in the intake chamber 90 and is furthermore particularly arranged between the intake filter 94 and an inlet 92 of the intake chamber 90. The heater 24 may be arranged between the intake filter 94 and the outlet 93.

[0021] The heating control of the second heating unit 20 is performed by a control device 80, which is a component of the intake air heating system 5. The control device 80 controls the second heating unit 20 so that the outside air is heated by the heater 24 in a high-load section in which a gas turbine load is higher than a first specified load. The heating control of the second heating unit 20 by the control device 80 may be performed only in the high-load section. Alternatively, the second heating unit 20 may also perform the heating operation in sections other than the high-load section (see Fig. 2).

[0022] Fig. Fig. 2 is a schematic graph showing portions of a heating operation of the second heating unit 20 according to an embodiment. The horizontal axis in the graph indicates the gas turbine load, and G1 corresponds to the first specified load (the same applies to Fig. 3 and Fig. 5). The first specified load is a load that is lower than a rated load of the gas turbine system 1, and is, for example, any gas turbine load of 75% or more and less than 95% of the rated load. The heating quantity in the Fig. 2 is not always constant. For example, the heating amount in the high-load section may be feedback-controlled according to the temperature of the exhaust gas discharged from the turbine 30, or the heating amount in the high-load section may be constant regardless of the temperature of the exhaust gas. In the present example, the feedback control is only executed in a case where the gas turbine load reaches a high specified load (in Fig. 3 (gas turbine load indicated by G3) that is higher than the first specified load, and the feedback control is not executed in a case where the gas turbine load is equal to or lower than the high specified load. The feedback control of the second heating unit 20 may be P control, PI control, or PID control, but in the present example, PI control is used. Further, the operation of the gas turbine system 1 according to an embodiment may always be a partial load operation. In this case, the specified upper limit load (gas turbine load indicated by reference symbol U), which is the maximum gas turbine load in the high load section, is lower than the rated load of the gas turbine system 1, and the operation in the load section where the load is higher than the specified upper limit load is not executed.For example, the specified upper limit load is any gas turbine load of 80% or more and less than 100% of the rated load. The specified upper limit load is a gas turbine load greater than the high specified load.

[0023] As in Fig. As shown in Figure 2, the second heating unit 20 performs the heating operation not only in the high-load section but also in an intermediate load section. The intermediate load section is a gas turbine load section in which the gas turbine load is equal to or lower than the first specified load and equal to or higher than a second specified load that is lower than the first specified load. G2 in Fig. 2 corresponds to the second specified load (the same applies to Fig. 3 and Fig. 5). For example, in the intermediate load section, feedback control of the heating amount by the second heating unit 20 is not performed. As a more specific example, in the intermediate load section, the opening degree of a second flow rate adjustment valve 22 (described later) of the second heating unit 20 is kept constant. The second specified load is any gas turbine load of 30% or more and less than 60% of the rated load of the gas turbine system 1.

[0024] According to the configuration described above, the outside air is heated by a heat source different from the compressed air in the high-load section. Accordingly, the flow rate of the compressed air flowing through the return flow path 15 as a heat source for heating the outside air can be reduced, and the decrease in the flow rate of the combustion gas supplied to the turbine 30 can be suppressed in the high-load section. Therefore, the intake air heating system 5 in which the operating efficiency of the gas turbine 3 is improved is realized. <details von erster heizeinheit 10>

[0025] Back to Fig. 1, the first heating unit 10 further includes a first flow rate adjustment valve 12 disposed in the return flow path 15. The heating operation of the first heating unit 10 is controlled by the control device 80. More specifically, the control device 80 transmits a control signal to the first flow rate adjustment valve 12 so that the flow rate of the compressed air flowing through the return flow path 15 is controlled and the heating amount of the first heating unit 10 with respect to the outside air is controlled.

[0026] In one embodiment, the heating operation by the first heating unit 10 is performed in a low-load section where the gas turbine load is lower than the second specified load. That is, the control device 80 controls the first heating unit 10 so that the first flow rate adjusting valve 12 opens the return flow path 15 in the low-load section. The opening of the first flow rate adjusting valve 12 does not necessarily mean the full opening of the first flow rate adjusting valve 12. In a case where the opening degree of the first flow rate adjusting valve 12 exceeds 0%, it is understood that the first flow rate adjusting valve 12 is open (the same applies to the second flow rate adjusting valve 22 described later).In addition, the heating control of the first heating unit 10 by the control device 80 may be performed only in the low load section or may be performed in sections other than the low load section (see . Fig. 3).

[0027] Fig. 3 is a schematic graph showing portions of a heating operation of the first heating unit 10 according to an embodiment. The horizontal axis in Fig. 3 indicates the gas turbine load. The heat quantity in the Fig. The operating portion of the first heating unit 10 shown in Figure 3 is not always constant. For example, the heating amount in the low-load portion may be feedback-controlled according to the gas turbine load, or the heating amount in the low-load portion may be constant regardless of the gas turbine load. In the present example, the heating amount of the first heating unit 10 in the low-load portion is feedback-controlled. The feedback control of the first heating unit 10 may be P control, PI control, or PID control, but in the present example, PI control is used.

[0028] As in Fig. 3, the first heating unit 10 performs the heating operation not only in the low-load section but also in the intermediate-load section. As a more specific example, in the intermediate-load section, the feedback control of the heating amount of the second heating unit 20 is performed. More specifically, in the intermediate-load section, the opening degree of the first flow rate adjustment valve 12 of the first heating unit 10 is feedback-controlled according to the exhaust gas temperature. Furthermore, in the example of Fig. 3, the heating operation by the second heating unit 20 is not performed in the high-load section. That is, the control device 80 controls the first heating unit 10 so that the first flow rate adjustment valve 12 closes the return flow path 15 in the high-load section.

[0029] According to the above configuration, when the first flow rate adjustment valve 12 is opened in the low-load section, the compressed air discharged from the compressor 7 is exhausted, and the outside air is heated by the exhausted compressed air. As a result, the flow rate of the compressed air flowing into the combustion chamber 8 is reduced, and the flow rate of the combustion gas for driving the turbine 30 is reduced. In this case, the fuel supplied to the combustion chamber 8 is increased to maintain the power of the gas turbine system 1. As a result, the amount of carbon monoxide (CO) generated can be suppressed because the combustion temperature in the combustion chamber 8 is increased. As described above, the generation of CO can be suppressed in the low-load section, and the operating efficiency of the gas turbine 3 can be improved in the high-load section.Furthermore, according to the above-described configuration, the first flow rate adjustment valve 12 closes the return flow path 15 in the high-load section. Accordingly, since the first heating unit 10 is not operated in the high-load section, the operating efficiency of the gas turbine 3 can be further improved. <details von zweiter heizeinheit 20>

[0030] Fig. 4 is a schematic view showing the second heating unit 20 according to an embodiment of the present disclosure. A heat source of the Fig. 4 shown second heating unit 20 is the one from the turbine 30 (see Fig. 1) exhaust gas. The heat source of the exhaust gas is recovered by a heat recovery steam generator 19, which is a component of the gas turbine system 1, and is used as the heat source of the second heating unit 20. The heat recovery steam generator 19 is configured to generate a heating medium from steam generator feedwater by using exhaust gas supplied from an exhaust passage 39 as a heat source. The heating medium is hot water or steam (superheated steam). For example, superheated steam is generated by heating the steam generator feedwater with the high-temperature exhaust gas that has flowed into the heat recovery steam generator 19 relatively recently. This superheated steam can be supplied to other devices constituting the gas turbine system 1, such as a steam turbine.Meanwhile, the low-temperature exhaust gas flowing near the outlet in the heat recovery steam generator 19 heats the steam generator feed water to generate hot water (this hot water may further flow in the heat recovery steam generator 19 and may be changed into the superheated steam by heat exchange with the high-temperature exhaust gas).

[0031] The description of the second heating unit 20 continues. The second heating unit 20 according to one embodiment includes a heating medium flow path 29 for guiding the heating medium generated by the heat recovery steam generator 19 to the suction chamber 90 of the suction flow path 9, the second flow rate adjusting valve 22 provided in the heating medium flow path 29, and a pipe section 25 that is the heater 24 arranged in the suction flow path 9. As described above, the second heating unit 20 is controlled by the control device 80. In the present example, when the second flow rate adjusting valve 22 is opened in response to the control signal transmitted from the control device 80 to the second flow rate adjusting valve 22, the heating medium is supplied from the heat recovery steam generator 19 to the pipe section 25 via the heating medium flow path 29.Furthermore, the flow rate of the heating medium flowing through the pipe section 25 is controlled by controlling the opening degree of the second flow rate adjusting valve 22. As a result, the heating amount of the second heating unit 20 is controlled with respect to the outside air. When the graph in . Fig. 2 as an example, when the gas turbine load is increased in the intermediate load section, the opening degree of the second flow rate adjustment valve 22 is increased, and the opening degree of the second flow rate adjustment valve 22 is substantially constant in the high load section. The heating medium supplied through the Fig. 4 is hot water, and the hot water has a higher temperature than the steam generator feed water before it flows into the heat recovery steam generator 19.

[0032] The control device 80 according to one embodiment controls the second heating unit 20 so that the second flow rate adjustment valve 22 closes the heating medium flow path 29 in the low-load section. Therefore, the second heating unit 20 does not perform the heating operation with respect to the outside air in the low-load section. According to the above configuration, in the low-load section, the flow rate of the compressed air flowing through the return flow path 15 can be increased by the amount of outside air not heated by the second heating unit 20. Therefore, the generation of CO can be further suppressed in the low-load section. <Beispiel für Heizsteuerung von erster Heizeinheit 10 und zweiter Heizeinheit 20>

[0033] Fig. Fig. 5 is a schematic graph showing a heating ratio of the first heating unit 10 and the second heating unit 20 according to an embodiment. The horizontal axis in Fig. 5 indicates the gas turbine load, and the vertical axis indicates the ratio of the heating amount of the first heating unit 10 to the heating amount of the second heating unit 20. For example, the first heating unit 10 performs all the heating of the outside air in the low-load section, and the second heating unit 20 performs all the heating in the high-load section. The vertical axis in Fig. 5 only indicates the ratio of the heating quantity of the first heating unit 10 to the heating quantity of the second heating unit 20. Therefore, the heating quantity relative to the outside air is not always constant across the low-load section, the intermediate-load section, and the high-load section.

[0034] In the Fig. 5, both the first heating unit 10 and the second heating unit 20 perform heating. As a more specific example, the control device 80 controls the first heating unit 10 and the second heating unit 20 such that the first flow rate adjustment valve 12 opens the return flow path 15 and the second flow rate adjustment valve 22 opens the heating medium flow path 29. In the Fig. In the intermediate load section shown in Figure 5, when the gas turbine load is increased, the heating ratio of the first heating unit 10 is reduced, and the heating ratio of the second heating unit 20 is increased. The reason is as follows.

[0035] In the feedback control of the first flow rate adjusting valve 12 in the intermediate load section, the opening degree of the first flow rate adjusting valve 12 is controlled, for example, based on a target value of the exhaust gas temperature and an actual measured value thereof from the turbine 30. In this case, the amount of fuel supplied to the combustor 8 to increase the gas turbine load is relatively large, and the exhaust gas temperature is increased as the gas turbine load is increased. As a result, the feedback control of decreasing the opening degree of the first flow rate adjusting valve 12 is executed, and the heating amount of the first heating unit 10 is reduced. Meanwhile, in the intermediate load section, the control is executed so that the heating amount of the second heating unit 20 is increased as the gas turbine load is increased.As a more specific example, the opening degree of the second flow rate adjustment valve 22 is increased as the gas turbine load increases. Therefore, as the gas turbine load increases in the intermediate load section, the heating ratio of the first heating unit 20 is reduced, and the heating ratio of the second heating unit 20 is increased.

[0036] According to the above configuration, the first heating unit 10 and the second heating unit 20 perform the outside air heating operation in the intermediate load section. As a result, it is possible to operate the gas turbine system 1 while maintaining a balance between both the suppression of CO generation and the operating efficiency of the gas turbine 3. <details von gasturbine 3>

[0037] Fig. 6 is a schematic view showing details of the gas turbine 3 according to an embodiment of the present disclosure. The gas turbine 3 in Fig. 6 is a two-shaft gas turbine. More specifically, the gas turbine 3 includes the compressor 7, a high-pressure turbine 33 having a first shaft 31 connected to a rotating shaft of the compressor 7, and a low-pressure turbine 34 having a second shaft 32 different from the first shaft 31. The high-pressure turbine 33 rotates integrally with the compressor 7. Furthermore, the low-pressure turbine 34 is configured to receive exhaust gas supplied from the high-pressure turbine 33 and is configured to rotate by using the exhaust gas as a power source. Exhaust gas discharged from the low-pressure turbine 34 flows to the exhaust passage 39.

[0038] An inlet guide vane is provided at an inlet of the compressor 7, and the intake amount of the compressor 7 is controlled by adjusting the opening degree of the inlet guide vane. In the twin-shaft gas turbine, the opening degree control of the inlet guide vane of the compressor 7 is performed to maintain a balance between the output of the high-pressure turbine 33 and the output of the compressor 7. Therefore, for example, in a case where the turbine inlet temperature is reduced according to a decrease in the amount of fuel supplied to the combustor 8 of the gas turbine 3, it is difficult to control the narrowing of the opening degree of the inlet guide vane to increase the turbine inlet temperature.In this regard, according to the above configuration, the second heating unit 20 heats the outside air using a heat source different from the compressed air in the high-load section, thereby increasing the turbine inlet temperature. Since the use of the compressed air discharged from the compressor 7 as a heat source is suppressed, it is also possible to suppress a decrease in the flow rate of the combustion gas flowing into the turbine 30. As described above, operating efficiency can be improved in the twin-shaft gas turbine. <Betriebsverfahren für Ansaugluft-Heizsystem 5>

[0039] Fig. 7 is a flowchart showing an operation method for the intake air heating system 5 according to an embodiment of the present disclosure. The method is executed by the control device 80 as an example. For example, the control device 80 is configured with a computer and includes a processor, a memory, and an external communication interface. The processor is a CPU, a GPU, an MPU, a DSP, a combination thereof, or the like. The processor according to other embodiments may be implemented by an integrated circuit such as a PLD, an ASIC, an FPGA, or an MCU. The memory is configured to temporarily or non-temporarily store various types of data and is implemented, for example, by at least one of a RAM, a ROM, and a flash memory.In accordance with an instruction of a program loaded into the memory, the processor of the control device 80 (hereinafter may be simply referred to as a "processor") executes control processing for operating the intake air heating system 5. During execution of the control processing, the processor transmits a control signal to the first flow rate adjusting valve 12 and the second flow rate adjusting valve 22. In the following description, steps may be abbreviated as "S."

[0040] First, it is determined whether the gas turbine load is included in the low-load section (S11). For example, the processor detects a command indicating a specific gas turbine load, and thus determines whether the gas turbine load is included in the low-load section. In a case where it is determined that the gas turbine load is included in the low-load section (S11: YES), a first heating unit control step of controlling the first heating unit 10 is executed (S13). The control method for the first heating unit 10 in the low-load section is as described above, and the processor transmits a predetermined control signal to the first flow rate adjustment valve 12. Furthermore, in this case, the processor transmits a control signal to the second flow rate adjustment valve 22 to close the heating medium flow path 29. After the execution of S13, the operation method for the intake air heating system 5 ends.

[0041] In a case where it is determined that the gas turbine load is not included in the low-load section (S11: NO), it is determined whether or not the gas turbine load is included in the intermediate load section (S15). The determination process at S15 is the same as the determination process at S11. In a case where it is determined that the gas turbine load is included in the intermediate load section (S15: YES), a control step of controlling the first heating unit 10 and the second heating unit 20 is executed (S17). The control process for the first heating unit 10 and the second heating unit 20 in the intermediate load section is as described above, and the processor transmits a predetermined signal to each of the first flow rate adjustment valve 12 and the second flow rate adjustment valve 22. After the execution of S17, the operation process for the intake air heating system 5 ends.

[0042] In a case where it is determined that the gas turbine load is not included in the intermediate load section (S15: NO), it is determined whether or not the gas turbine load is included in the high load section (S19). The determination process at S19 is the same as the determination process at S11. In a case where it is determined that the gas turbine load is included in the high load section (S19: YES), the second heating unit control step of controlling the second heating unit 20 is executed (S21). The control process for the second heating unit 20 in the high load section is as described above. Furthermore, in this case, the processor transmits a control signal for the first flow rate adjustment valve 12 to close the return flow path 15. After the execution of S21, the operation process for the intake air heating system 5 ends.In a case where it is determined that the gas turbine load is not included in the high load section (S19: NO), the step returns to S11. <zusammenfassung>

[0043] The contents described in some of the embodiments described above are understood, for example, as follows. 1) An intake air heating system (5) according to at least one embodiment of the present disclosure is the intake air heating system (5) configured to heat outside air flowing through an intake flow path (9) communicating with a compressor (7) of a gas turbine (3), the intake air heating system (5) comprising: a first heating unit (10) including a return flow path (15) for returning a portion of compressed air discharged from the compressor (7) to the intake flow path (9); a second heating unit (20) including a heater (24) configured to heat the outside air by using a heat source other than the compressed air; and a control device (80) configured to control the second heating unit (20) so that the outside air is heated by the heater (24) in a high load section in which a gas turbine load is higher than a first specified load.

[0044] According to the configuration of 1) above, the outside air is heated by a heat source different from the compressed air in the high-load section. Accordingly, the flow rate of the compressed air flowing through the return flow path (15) as a heat source for heating the outside air can be reduced, and the decrease in the flow rate of the combustion gas supplied to the turbine (30) can be suppressed in the high-load section. Therefore, the intake air heating system (5) in which the operating efficiency of the gas turbine (3) is improved is realized.

[0045] 2) In some embodiments, the intake air heating system (5) is the intake air heating system (5) according to 1), wherein the first heating unit (10) further includes a first flow rate adjusting valve (12) arranged at the return flow path (15), and the control device (80) is configured to control the first heating unit (10) such that the first flow rate adjusting valve (12) opens the return flow path (15) in a low load section in which the gas turbine load is lower than a second specified load which is lower than the first specified load.

[0046] According to the configuration of 2) above, when the first flow rate adjusting valve (12) is opened in the low-load section, the compressed air discharged from the compressor (7) is exhausted, and the outside air is heated by the exhausted compressed air. As a result, the flow rate of the compressed air flowing into the combustion chamber (8) is reduced, and the flow rate of the combustion gas driving the turbine (30) is reduced. In this case, the fuel supplied to the combustion chamber (8) is increased to maintain the output of the gas turbine system (1). As a result, the amount of carbon monoxide (CO) generated can be suppressed because the combustion temperature in the combustion chamber (8) is increased. As described above, the generation of CO can be suppressed in the low-load section, and the operating efficiency of the gas turbine (3) can be improved in the high-load section.

[0047] 3) In some embodiments, the intake air heating system (5) is the intake air heating system (5) according to 2), wherein the control device (80) is configured to control the first heating unit (10) such that the first flow rate adjusting valve (12) closes the return flow path (15) in the high load section.

[0048] According to the configuration of the above 3), since the first heating unit (10) is not operated in the high load section, operating efficiency of the gas turbine (3) can be further improved.

[0049] 4) In some embodiments, the intake air heating system (5) is the intake air heating system (5) according to 3), wherein the second heating unit (20) contains: a heating medium flow path (29) for guiding a heating medium generated by heating steam generator feed water with a heat recovery steam generator (19) to which exhaust gas from the gas turbine (3) is supplied, to the intake flow path (9), a second flow rate adjusting valve (22) provided in the heating medium flow path (29), and a pipe section (25) arranged in the intake flow path (9) and which is the heater (24) configured to supply the heating medium from the heating medium flow path (29), and the control device (80) is configured to control the second heating unit (20) such that the second flow rate adjusting valve (22) closes the heating medium flow path (29) in the low load section.

[0050] According to the configuration of 4 above, in the low-load section, the flow rate of the compressed air flowing through the return flow path (15) can be increased by the amount of outside air not heated by the second heating unit (20). Therefore, the generation of CO can be further suppressed in the low-load section.

[0051] 5) In some embodiments, the intake air heating system (5) is the intake air heating system (5) according to 4), wherein the control device (80) is configured to control the first heating unit (10) and the second heating unit (20) such that, in an intermediate load section in which the gas turbine load is equal to or higher than the second specified load and equal to or lower than the first specified load, the first flow rate adjusting valve (12) opens the return flow path (15) and the second flow rate adjusting valve (22) opens the heating medium flow path (29).

[0052] According to the configuration of the above 5), the first heating unit (10) and the second heating unit (20) perform the outside air heating operation in the intermediate load section. As a result, it is possible to operate the gas turbine system (1) while maintaining a balance between both the suppression of CO generation and the operating efficiency of the gas turbine (3).

[0053] 6) An operation method for the intake air heating system (5) according to at least one embodiment of the present disclosure is the operation method for the intake air heating system (5) configured to heat outside air flowing through the intake flow path (9) communicating with the compressor (7) of the gas turbine (3), wherein the intake air heating system (5) contains: the first heating unit (10) including the return flow path (15) for returning a portion of compressed air discharged from the compressor (7) to the intake flow path (9), and the second heating unit (20) containing the heater (24) configured to heat the outside air by using a heat source other than the compressed air, and the operating method comprises: a second heating unit control step (S21) of controlling the second heating unit (20) so that the outside air is heated by the heater (24) in a high load section in which a gas turbine load is higher than a first specified load.

[0054] According to the configuration of the above 6), the operation method for the intake air heating system (5) in which operation efficiency of the gas turbine (3) is improved is realized for the same reason as the above 1).

[0055] 7) The gas turbine system (1) according to at least one embodiment of the present disclosure comprises: the intake air heating system (5) according to one of 1) to 5); and the gas turbine.

[0056] According to the configuration of the above 7), the gas turbine system (1) in which operating efficiency of the gas turbine (3) is improved is realized for the same reason as the above 1).

[0057] 8) In some embodiments, the gas turbine system (1) is the gas turbine system (1) according to 7), wherein the gas turbine (3) is a two-shaft gas turbine containing: the compressor (7), a high-pressure turbine (33) having a first shaft (31) connected to a rotating shaft of the compressor (7), and a low-pressure turbine (34) having a second shaft (32) different from the first shaft (31) and configured to supply exhaust gas from the high-pressure turbine (33).

[0058] In the twin-shaft gas turbine, the opening degree control of the inlet guide vane of the compressor (7) is performed to maintain a balance between the performance of the high-pressure turbine (33) and the performance of the compressor (7). Therefore, for example, in a case where the turbine inlet temperature is reduced according to a decrease in the amount of fuel supplied to the combustor (8) of the gas turbine (3), it is difficult to perform the control of narrowing the opening degree of the inlet guide vane so as to increase the turbine inlet temperature. In this regard, according to the configuration of the above 8), the second heating unit (20) heats the outside air using a heat source different from the compressed air, thereby increasing the turbine inlet temperature.Since the use of the compressed air discharged from the compressor (7) as a heat source is suppressed, it is also possible to suppress a decrease in the flow rate of the combustion gas flowing into the turbine (30). As described above, operating efficiency in the twin-shaft gas turbine can be improved. List of reference symbols 1 gas turbine system 3 gas turbines 5 Intake air heating system 7 Compressor 9 Intake flow path 10 first heating unit 12 first flow rate adjustment valve 15 Return flow path 19 heat recovery steam generators 20 second heating unit 22 second flow rate adjustment valve 24 heating 25 pipe section 29 Heating medium flow path 30 turbines 31 first wave 32 second wave 33 High-pressure turbine 34 Low-pressure turbine 80 Control device QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2022

[0002] JP 127617

[0002] JP 2000-097046

[0004] < / zusammenfassung> < / details> < / details> < / details>

Claims

[1] An intake air heating system configured to heat outside air flowing through an intake flow path communicating with a compressor of a gas turbine, the intake air heating system comprising: a first heating unit including a return flow path for returning a portion of compressed air discharged from the compressor to the intake flow path; a second heating unit including a heater configured to heat the outside air by using a heat source other than the compressed air; and a control device configured to control the second heating unit so that the outside air is heated by the heater in a high load section in which a gas turbine load is higher than a first specified load. [2] Intake air heating system according to claim 1, wherein the first heating unit further includes a first flow rate adjusting valve arranged at the return flow path, and the control device is configured to control the first heating unit such that the first flow rate adjusting valve opens the return flow path in a low load section in which the gas turbine load is lower than a second specified load that is lower than the first specified load. [3] The intake air heating system according to claim 2, wherein the control device is configured to control the first heating unit so that the first flow rate adjusting valve closes the return flow path in the high load section. [4] An intake air heating system according to claim 2 or 3, wherein the second heating unit includes: a heating medium flow path for guiding a heating medium generated by heating steam generator feedwater with a heat recovery steam generator to which exhaust gas from the gas turbine is supplied, to the intake flow path, a second flow rate adjusting valve provided in the heating medium flow path, and a pipe section arranged in the intake flow path and which is the heater configured to supply the heating medium from the heating medium flow path, and the control device is configured to control the second heating unit such that the second flow rate adjusting valve closes the heating medium flow path in the low load section. [5] The intake air heating system according to claim 4, wherein the control device is configured to control the first heating unit and the second heating unit such that, in an intermediate load section in which the gas turbine load is equal to or higher than the second specified load and equal to or lower than the first specified load, the first flow rate adjusting valve opens the return flow path and the second flow rate adjusting valve opens the heating medium flow path. [6] An operating method for an intake air heating system configured to heat outside air flowing through an intake flow path communicating with a compressor of a gas turbine, the intake air heating system including: a first heating unit including a return flow path for returning a portion of compressed air discharged from the compressor to the intake flow path, and a second heating unit including a heater configured to heat the outside air by using a heat source other than the compressed air, and the operating method comprises: a second heating unit control step of controlling the second heating unit so that the outside air is heated by the heater in a high load section in which a gas turbine load is higher than a first specified load. [7] Gas turbine system comprising: the intake air heating system according to one of claims 1 to 3; and the gas turbine. [8] A gas turbine system according to claim 7, wherein the gas turbine is a two-shaft gas turbine including: the compressor, a high-pressure turbine having a first shaft connected to a rotating shaft of the compressor, and a low-pressure turbine having a second shaft different from the first shaft and configured to supply exhaust gas from the high-pressure turbine.

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