JP5119676B2 - High humidity gas turbine - Google Patents

Description

  The present invention relates to a high-humidity gas turbine that improves output and efficiency by humidifying and reheating air supplied to a gas turbine and driving the turbine with a high-humidity combustion gas.

  The present invention relates to a technology related to operation control of a high-humidity gas turbine that humidifies and reheats the air supplied to the gas turbine to drive the turbine with high-humidity combustion gas, and is stable and high-speed even when the combustion air temperature fluctuates. Patent Document 1 discloses a technique for controlling the flow rate of fuel supplied to a combustor based on the rotational speed at the time of starting the turbine in order to enable the plant to be started.

JP 2006-57607 A

  The high-humidity-use gas turbine has a smaller suction flow rate of the compressor than the simple cycle gas turbine. In addition, the high-humidity-use gas turbine does not humidify the compressor intake air when starting up. Therefore, the high-humidity utilization gas turbine requires a large amount of power for startup. That is, the drive motor of the high-humidity gas turbine has a larger capacity than the drive motor that drives the simple cycle gas turbine, which may increase the installation space and cost. Further, if the drive motor has a small capacity, there is a problem that the flow rate of air supplied to the combustor at the time of start-up is reduced and the exhaust temperature of the gas turbine is increased.

  Patent Document 1 discloses an operation control and control device for a high-humidity gas turbine, but the startup of the gas turbine compressor due to the flow balance between the compressor of the high-humidity gas turbine and the turbine is disclosed. Not listed.

  An object of the present invention is to reduce power required for driving a compressor in a gas turbine including an intake air humidifier that adds moisture to compressor intake air.

In order to solve the above problems, the present invention is driven by a compressor that compresses air, a combustor that mixes and burns compressed air and fuel compressed by the compressor, and combustion gas generated by the combustor. In the gas turbine comprising a turbine that performs the above operation and an intake air humidifier that adds moisture to the intake air of the compressor, the compressor has an extraction port, and the air from the extraction port is activated according to the number of rotations at the time of startup. A bleed air amount restraining means capable of restraining the bleed air amount is provided , and the bleed air amount restraining means is a variable mechanism that can vary the angle of the blade provided in the middle stage or the rear stage stationary blade of the compressor. And

  ADVANTAGE OF THE INVENTION According to this invention, in a gas turbine provided with the intake air humidifier which adds moisture to compressor intake air, the motive power required for a compressor drive can be reduced.

(Comparative example)
As a comparative example, a conventional high humidity gas turbine will be described with reference to FIG. FIG. 10 is a schematic view of a high-humidity gas turbine as a comparative example.

  First, the operation until the atmosphere sucked into the compressor in the high-humidity utilization cycle becomes moisture air and is finally discharged to the outside as exhaust gas will be described. In the mixer 12 which is an intake humidifier for adding moisture to the compressor intake air, water 61 is sprayed on the intake air 41 and moisture air 42 is generated. The humid air 42 generated by the mixer 12 is compressed by the compressor 1. The compressed air generated by the compressor 1 is once extracted at the gas path outlet once. The high-pressure air 43 extracted from the compressor outlet is supplied to the cooler 10 and cooled by the recovered water from the water recovery device 9 and the recovered water 63 from the humidifier 11. The high-pressure air 44 cooled by the cooler 10 is humidified by the humidifier 11 using water 64 heated by the cooler 10 and water 66 heated by the feed water heater 7. The humid air 45 humidified by the humidifier 11 is supplied to the regenerative heat exchanger 6 and is overheated by the exhaust gas 48 from the turbine 3. The humid air 46 generated by the regenerative heat exchanger 6 is supplied to the combustor 2. The humid air 46 supplied to the combustor 2 is mixed and burned with the fuel 31 in the combustor 2. The generated combustion gas 47 flows into the turbine 3 and drives the turbine 3 to rotate. The exhaust gas 48 discharged from the turbine 3 is recovered by the regenerative heat exchanger 6 and then supplied to the feed water heater 7 as the exhaust gas 52. The exhaust gas 52 heat-exchanged with the water 65 by the feed water heater 7 is supplied to the exhaust gas reheater 8 as the exhaust gas 53. The exhaust gas 53 heat-exchanged with the exhaust gas 50 by the exhaust gas reheater 8 is supplied as the exhaust gas 49 to the water recovery device 9. In the water recovery apparatus 9, the exhaust gas 49 is cooled by the cooling water 62, and the moisture in the exhaust gas 49 is condensed and recovered as water. The exhaust gas 50 discharged from the water recovery device 9 is discharged out of the system as exhaust gas 51 by exchanging heat with the exhaust gas 53 in the exhaust gas reheater 8. The exhaust gas 51 is heated by the exhaust gas resuperheater 8 to suppress the possibility of generation of white smoke. The compressor 1 and the turbine 3 are connected by an intermediate shaft. A generator 4 that converts shaft power generated by the turbine 3 into electric power is also connected to the rotating shaft of the compressor 1.

Next, a water circulation system will be described with reference to FIG. In order to supply water to the water recovery device 9 that cools the exhaust gas 49 and recovers moisture, the high-humidity-use gas turbine system of this comparative example includes a water tank 13 that replenishes water into the system. The water supplied from the water tank 13 is supplied to the cooler 14 and cooled. The water recovery device 9 cools the exhaust gas 49 discharged from the exhaust gas reheater 8 with the cooled cooling water 62, condenses moisture, and recovers moisture. Further, the water discharged from the water recovery device 9 is supplied again to the cooler 14 and also supplied to the water treatment device 15 that pretreats the water for supply to the gas turbine side. The water 61 treated by the water treatment device 15 is supplied to the mixer 12 that sprays the water 61 on the intake air 41 to generate the moisture air 42, while the water 63 treated by the water treatment device 15 is It is also supplied to the cooler 10 that cools the high-pressure air 43. The water 63 supplied to the cooler 10 is heated by the cooler 10, and the heated water 64 is supplied to the humidifier 11. The water 64 is used by the humidifier 11 to humidify the high-pressure air 44 supplied from the cooler 10. The used water is supplied again to the cooler 10 and also to the feed water heater 7. In the feed water heater 7, heated water 66 is generated by heating the water 65 in the feed water circulation system discharged from the humidifier 11 using the exhaust gas 52 as a heat source. This heated water 66 is supplied to the humidifier 11. As described above, the humidifier 11 is supplied with water heated not only from the cooler 10 but also from the feed water heater 7.

When the high-humidity gas turbine is rated for operation, the compressor intake air is humidified by the mixer 12, and the humidifier 11 also adds moisture to the high-pressure air 43 extracted from the compressor 1 outlet. The air flow increases by the added moisture. The flow rate balance between the turbine and the compressor in a normal simple cycle gas turbine is as follows. When the operating flow rate of the turbine is 100%, the operating air flow rate of the compressor is 98% and the fuel flow rate supplied by the combustor is 2%. . However, in a gas turbine that uses high humidity, the air flow rate is increased by about 20% by adding moisture to the high-pressure air 43 that has been entirely extracted from the compressor. Therefore, in the high-humidity gas turbine, the increase in the air flow rate is taken into consideration, and the suction flow rate of the compressor needs to be about 78% that of the simple cycle gas turbine.

  When starting up the high-humidity gas turbine, it is necessary to avoid a rotating stall and a surging phenomenon in the compressor in order to start up the compressor stably, as in the simple cycle gas turbine. Here, surging is a phenomenon in which when the pressure ratio is increased, the operation becomes unstable due to pressure with a strong sound suddenly at a certain pressure ratio, intense pulsation of the flow and vibration of the machine.

  When moisture is added to the intake air of the compressor at the time of starting the high-humidity gas turbine, the blade load on the rear stage side of the compressor may increase and the surge margin may be reduced. Further, when the extracted air extracted from the compressor is humidified by the humidifier, the turbine flow rate increases, the operating pressure ratio of the compressor connected to the turbine increases, and the surge margin decreases. Therefore, it is desirable not to add moisture to the compressor intake when the high humidity gas turbine is started.

  In the high humidity gas turbine, the flow rate ratio between the turbine and the compressor is set in consideration of humidification of the compressor intake air during rated operation. Therefore, the flow rate balance is not maintained at the start-up time when the compressor intake air is not humidified. That is, when moisture at the time of starting the gas turbine is not added, the operating flow rate to the turbine is smaller than that of the simple cycle gas turbine, so that the driving power of the compressor is relatively reduced.

  One way to compensate for this relative reduction in drive power is to increase the capacity of the compressor drive motor. However, when the capacity of the drive motor is increased, the installation space for the gas turbine is increased and the cost is also increased. Since the main part of the gas turbine is housed in a box-type enclosure, when the existing gas turbine is diverted to a high-humidity utilization cycle, the drive motor has a large capacity and is installed in the existing enclosure. There is a risk that it will be impossible.

  In addition, when the gas turbine is driven in a state where the capacity of the drive motor is insufficient, the flow choke on the rear stage side of the axial compressor, the air flow rate to the combustor is reduced, and the exhaust temperature of the turbine becomes high. there is a possibility. When this exhaust temperature exceeds the set exhaust temperature control line, the gas turbine trips and stable startup cannot be ensured.

Hereinafter, the structure of the compressor of the high-humidity utilization gas turbine that is Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a main flow channel in an axial compressor 1 of a high-humidity gas turbine that is Embodiment 1. FIG. In FIG. 1, the stationary vanes and the moving blades in the intermediate portion are omitted, and the compressor flow path in which the stationary blades and the moving blades are omitted is indicated by dotted lines. FIG. 2 is a cross-sectional view taken along the line AA in FIG. In FIG. 2, the cross-sectional view of the wing is omitted for simplicity. The compressor 1 is fixed to an outer casing 73 that is positioned between the compressor rotor that rotates on the same rotating shaft as the turbine 3, the moving blade 71 that is implanted in the rotating compressor rotor, and the front and rear of the moving blade 71. The stationary vane 72 is made up of. The flow path of the compressor 1 through which the air 42 as the compressor main flow fluid passes is formed by an inner surface 81 that is an outer peripheral surface of the compressor rotor 74 and an outer surface 82 that is an inner peripheral surface of the casing 73. The casing 73 is provided with a bleed slit 91 and a bleed port 92, and a plurality of bleed pipes 93 (four in FIG. 2) are arranged in the circumferential direction. The stationary blade 72 on the front stage side of the compressor is provided with a variable mechanism 101 that can vary the blade angle in order to prevent a rotating stall at startup and to ensure a surge margin.

  The feature of this embodiment is that a variable mechanism 102 different from the variable mechanism 101 of the front-stage stationary blade 72 is provided on the intermediate-stage or rear-stage stationary blade of the compressor. In FIG. 1, the variable mechanism 102 is provided only on one stage of stationary blades, but the variable mechanism 102 may be provided on a plurality of stages of stationary blades.

  The operation at the time of starting the gas turbine will be described with reference to FIG. FIG. 3A shows a simplified system diagram of the high-humidity utilization gas turbine of this embodiment. FIG.3 (b) shows the opening degree of the variable stationary blade with respect to the rotation speed of a compressor. FIG. 3C shows the bleed valve opening relative to the rotational speed of the compressor. In order to start the compressor 1 stably, the stationary blade 72 provided with the variable mechanism 101 on the front stage side of the compressor, the extraction port 92, and the extraction piping 93 are scheduled. The variable stationary blade 72 is controlled by the rotational speed of the gas turbine, and the angle is set to the minimum opening state from the starting time to a certain rotational speed, thereby improving the matching of the blade row on the compressor front stage side. Then, as the rotational speed increases, the opening degree is gradually opened and is scheduled to become maximum at the rated rotational speed. The bleed air is also controlled by the number of revolutions, and the bleed valve is set to the maximum opening from the start to a certain number of rotations, the opening is set to the minimum after a certain number of rotations, and the bleed air at the minimum opening is used for cooling the turbine blades. Used. When the opening degree of the extraction valve is maximum, a part of the extracted compressed air is introduced into the turbine blade cooling system, and the other is released to the atmosphere via the exhaust duct of the turbine.

  In a high-humidity gas turbine using a compressor that does not have the variable mechanism 102 in the intermediate stage or the rear stage stationary blade of the compressor, the air flow rate of the bleed air at startup is about 20 to 25% of the compressor suction flow rate. And big. Therefore, when starting the high-humidity gas turbine, the amount of air supplied to the combustor 2 is increased by reducing the extraction flow rate, and the flow rate of the working fluid for driving the turbine is increased. It is necessary to make the 402 capacity as small as possible.

  The purpose of extraction at the time of starting the compressor is to suppress stall of the blade row on the front side of the compressor and to suppress choke of the blade row on the rear side of the compressor. Since the stationary blade 72 on the front stage side of the compressor includes the variable mechanism 101, choke suppression of the blade row is possible. In the high-humidity-use gas turbine of this embodiment, by providing the variable mechanism 102 in the intermediate stage or the rear stage side stationary blade of the compressor, it becomes possible to suppress the choke of the compressor middle stage or the rear stage side, and the bleed flow rate Can be reduced. Thereby, since the flow volume of the compressed air supplied to the combustor 2 can be increased, the working fluid flow volume of the turbine can be increased, and the capacity of the drive motor 402 of the compressor can be reduced. Further, since it is possible to optimize the matching of the compressor blade rows, it is possible to improve the efficiency of the compressor at the partial rotation speed and the reliability of the stable startup.

  Like the gas turbine of the present embodiment, the amount of air that can be supplied to the combustor by including air discharge amount suppression means that can reduce the flow rate of air extracted from the middle stage of the compressor and discharged directly to the atmosphere. And the working fluid flow rate of the turbine can be increased, and the compressor driving force required at startup can be reduced. The air discharge amount suppression means of the gas turbine of the present embodiment is a variable mechanism 101 provided on the front stage stationary blade and a variable mechanism 102 provided on the intermediate stage or rear stage stationary blade.

  In the present embodiment, the compressor front-side blade means a blade installed at a position where there is a concern about stalling as a problem when air is not appropriately extracted when the compressor is started. Similarly, the compressor rear-stage wing means a wing installed at a position where choking is a concern. The compressor middle stage blade means a compressor blade installed between the front stage side blade and the rear stage side blade.

  A high-humidity utilization gas turbine that is Embodiment 2 of the present invention will be described with reference to FIGS. 4, 5, and 6. In addition, about the apparatus which overlaps with FIGS. 1-3, the number is the same and detailed description is abbreviate | omitted. FIG. 4 shows a cross-sectional view of a main flow channel in the axial flow compressor 1 of the high humidity gas turbine according to the second embodiment. In FIG. 4, the stationary vanes and the moving blades in the intermediate portion are omitted, and the compressor flow paths in which the stationary blades and the moving blades are omitted are indicated by dotted lines. FIG. 5 is a cross-sectional view taken along the line AA in FIG. In FIG. 4, the cross-sectional view of the wing is omitted for simplicity. FIG. 6 shows a simplified system diagram of a high-humidity utilization gas turbine according to the second embodiment.

  As in the first embodiment, the high-humidity gas turbine according to the present embodiment includes one or a plurality of stationary blades provided with the variable mechanism 102 at the middle stage or the rear stage of the compressor. Further, by utilizing the effect of reducing the amount of extraction at the time of starting the compressor by providing the variable mechanism 102, the extraction system that is released to the atmosphere via the exhaust duct of the turbine is omitted. That is, the entire amount of air extracted from the compressor and passing through the plurality of extraction pipes 94 arranged in the circumferential direction of the casing 73 is used for cooling the blades of the turbine. Since the air for cooling the blades is extremely small compared to the air released to the atmosphere when the compressor without the variable mechanism 102 is started, the diameter of the pipe provided in the bleed portion can be made much smaller. It is.

  The high-humidity gas turbine of the present embodiment can suppress an increase in the capacity of the compressor drive motor by reducing the extraction flow rate as in the first embodiment. In addition, since the diameter of the bleed pipe can be made much smaller, workability at the time of assembly and inspection can be improved. Significant cost reduction can be expected. Further, in the gas turbine of this embodiment, since the entire amount of air extracted at the time of start-up is effectively used for cooling the turbine blades, there is no air to be released to the atmosphere through the exhaust duct at the time of start-up, and high-efficiency operation is achieved. Is possible.

  A high humidity gas turbine that is Embodiment 3 of the present invention will be described with reference to FIG. The same reference numerals are given to the same devices as those in FIG. 1, and detailed description thereof is omitted. FIG. 7 shows a cross-sectional view of the main flow channel in the axial flow compressor 1 of the high-humidity utilization gas turbine that is Embodiment 3. As shown in FIG. In FIG. 7, the stationary vanes and the moving blades in the middle part are omitted, and the compressor flow path in which the stationary blades and the moving blades are omitted is indicated by dotted lines.

  As in the first embodiment, the high-humidity gas turbine according to the present embodiment includes one or a plurality of stationary blades provided with the variable mechanism 102 at the middle stage or the rear stage of the compressor. Further, the extraction system is omitted by utilizing the effect of reducing the amount of extraction when the compressor is started by providing the variable mechanism 102. That is, the entire amount of air flowing into the compressor 1 is configured to flow into the combustor 2.

  Since the gas turbine of the present embodiment does not extract air from the compressor 1 at the time of startup, the entire amount of compressor intake air can be used as combustion air. Therefore, the drive motor capacity used for driving the compressor 1 can be reduced. In addition, since no bleed piping is required, the cost can be reduced. Workability during assembly and inspection can also be improved. Furthermore, the normal compressor casing is divided at the bleed port for processing the bleed port, and this divided part is fastened with bolts. If a compressor having no bleed port is used as in the present embodiment, air leakage from the contact surface of the bleed port portion casing due to temperature change of the compressor casing during rated operation can be eliminated, and the compressor Efficiency can be improved. And since a casing structure can be simplified, cost reduction is also possible. In addition, during the rated operation of the high-humidity gas turbine, water is sprayed on the intake air of the compressor. However, in the vicinity of the side wall of the compressor, moisture may not be evaporated and accumulate as a drain. This accumulation of drain is particularly likely to occur in a bleed portion having a complicated structure, and the bleed portion including the bleed piping may corrode due to the influence of the accumulation of the drain. In the compressor of the gas turbine of the present embodiment, there is no bleed portion in which the drain easily accumulates, so that corrosion due to the accumulation of the drain can be suppressed, and the reliability of the gas turbine can be improved.

  In the gas turbine of this embodiment, compressor bleed air is not used for cooling the turbine blades. As the cooling air for the turbine blade, for example, the humid air 45 after being humidified by the humidifier 11 can be used.

  A high humidity gas turbine that is Embodiment 4 of the present invention will be described with reference to FIG. FIG. 8 shows a system diagram of a high-humidity-use gas turbine that is Embodiment 4. In addition, about the apparatus which overlaps with FIG. 10, the number is the same and detailed description is abbreviate | omitted. The feature of the gas turbine of the present embodiment is that it has a separate compressor 201 that pressurizes the extracted air extracted from the compressor 1. This separate compressor 201 is driven by a motor 202.

  When starting up the high-humidity gas turbine, it is desirable to use the extracted air extracted by the compressor as the working fluid of the turbine. Therefore, the extracted air 301 extracted from the compressor is introduced into the separate compressor 201 driven by the motor 202. The extraction air 301 is pressurized by the separate compressor 201 so as to be higher than the pressure of the humidified air 46 compressed by the compressor 1, humidified by the humidifier 11, and heat-exchanged by the regenerative heat exchanger 6. The pressurized compressed air 302 is supplied to the combustor 2 and is mixed with the fuel 31 in the same manner as the humidified air 46 and used as combustion air. The combustion gas 47 is supplied to the turbine 3 and drives the turbine 3. With this configuration, the air extracted from the compressor 1 can be effectively used as combustion air without being released to the atmosphere. The total flow rate of the air sucked by the compressor 1 can be used as the working air of the turbine, and it is possible to suppress the increase in the capacity of the drive motor that starts the compressor and improve the efficiency.

  Note that the separate compressor 201 for boosting has a small capacity with respect to the drive motor 402 that drives the gas turbine, and is therefore inexpensive in terms of cost compared to increasing the capacity of the drive motor.

  A high-humidity utilization gas turbine that is Embodiment 5 of the present invention will be described with reference to FIG. FIG. 9 is a system diagram of a high-humidity-use gas turbine that is Embodiment 5. In addition, about the apparatus which overlaps with FIG. 8, FIG. 10, the number is the same and detailed description is abbreviate | omitted. The feature of the gas turbine of the present embodiment is that the extracted air 303 whose pressure has been increased by the separate compressor 201 is supplied to the humidifier 11.

  The operation of the gas turbine of this embodiment will be described. Extracted air 301 extracted from the compressor is introduced into a separate compressor 201 driven by a motor 202. Then, after being compressed by the compressor 1 and cooled by the cooler 10, the pressure is increased by the separate compressor 201 so as to be higher than the pressure of the compressed air 44 supplied to the humidifier 11. The pressurized compressed air 303 is supplied to the humidifier 11, and is mixed with the compressed air 44 and humidified by the humidifier 11. The mixed moisture air 45 is heat-exchanged by the regenerative heat exchanger 6, then mixed with fuel by the combustor 2, and the turbine 3 is driven by the combustion gas 47.

In the gas turbine of the present embodiment, the extracted air 301 extracted from the compressor 1 is boosted by the separate compressor 201 and introduced into the humidifier 11 and finally used as the working gas of the turbine. The capacity of the drive motor that starts the machine can be suppressed. In addition, since the compressed air 303 whose pressure has been increased by the separate compressor 201 is introduced into the humidifier 11 and mixed with the compressed air, the effect of promoting the mixing is higher than mixing the fluid in the pipe. In addition, since the compressor bleed air is also humidified by the humidifier 11 at the time of startup, the effect of suppressing the increase in the capacity of the drive motor is further increased by increasing the air flow rate.

Sectional drawing of the mainstream flow path in the axial flow compressor 1 of the high-humidity utilization gas turbine which is Example 1 is shown. AA sectional drawing of FIG. 1 is shown. (A) shows the simplified system diagram of the high-humidity utilization gas turbine of a present Example. (B) shows the opening degree of the variable stationary blade with respect to the rotational speed of the compressor. (C) shows the opening degree of the bleed valve with respect to the rotational speed of the compressor. Sectional drawing of the mainstream flow path in the axial flow compressor 1 of the high-humidity utilization gas turbine which is Example 2 is shown. AA sectional drawing of FIG. 4 is shown. The simplified system diagram of the high humidity utilization gas turbine which is Example 2 is shown. Sectional drawing of the mainstream flow path in the axial flow compressor 1 of the high-humidity utilization gas turbine which is Example 3 is shown. The system diagram of the high humidity utilization gas turbine which is Example 4 is shown. The systematic diagram of the high-humidity utilization gas turbine which is Example 5 is shown. The schematic of the high-humidity utilization gas turbine which is a comparative example is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Combustor 3 Turbine 4 Generator 6 Regenerative heat exchanger 7 Feed water heater 11 Humidifier 12 Mixer 71 Rotor blade 72 Stator blade 73 Casing 91 Extraction slit,
92 Extraction port 93, 94 Extraction piping 101, 102 Variable mechanism 201 Separate compressor 402 Drive motor

Claims (5)

A compressor that compresses air, a combustor that mixes and burns compressed air and fuel compressed by the compressor, a turbine that is driven by combustion gas generated by the combustor, and intake air of the compressor In a gas turbine having an intake air humidifier for adding moisture,
The compressor has a bleed port, and is provided with a bleed air amount suppression means capable of suppressing the bleed amount of air from the bleed port according to the number of revolutions at the time of startup ,
The high-humidity-use gas turbine is characterized in that the extraction air amount suppression means is a variable mechanism that can vary the angle of the blade provided in the middle stage or the rear stage stationary blade of the compressor . The gas turbine according to claim 1, wherein
A gas turbine characterized in that the entire amount of bleed air of the compressor is supplied to a cooling flow path of a turbine blade . The gas turbine according to claim 1 , wherein
A gas turbine configured to supply a total amount of intake air of the compressor to the combustor. The gas turbine according to claim 3 , wherein
A gas turbine comprising a separate compressor for compressing air extracted from the compressor . In the method of operating the intake humidifier gas turbine with the addition of moisture to the compressor inlet air, at startup, when discharging directly atmosphere bled air from the compressor the middle stage, middle or later stage of the compressor An operation method of a gas turbine, characterized in that an exhaust air amount is reduced by using an air exhaust amount suppression means which is a variable mechanism capable of changing a blade angle provided on a side stationary blade .

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