JP2019027387A - Combined cycle power generation plant, and its operation method and modification method - Google Patents

Abstract

To solve a thermal problem in a gas turbine exhaust gas utilization-side system in quick start/stop of a combined cycle power generation plant.SOLUTION: In a combined cycle power generation plant composed of a gas turbine, an exhaust heat recovery boiler generating at least high-pressure and low-pressure steam from an exhaust gas of the gas turbine, a steam turbine driven by the high-pressure and low-pressure stream from the exhaust heat recovery boiler, and a power generator driven by at least the gas turbine of the gas turbine and the steam turbine, and generating power, a low pressure steam drum generating low-pressure steam of the exhaust heat recovery boiler is provided with a low-pressure steam header to which the steam generated in the low-pressure steam drum is introduced, and the steam stored in the low-pressure steam header is used as auxiliary steam in the combined cycle power generation plant before establishment of generation of high-pressure steam.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a combined cycle power plant that obtains electric power from a driving force of a gas turbine and a driving force of a steam turbine driven by steam generated from high-temperature exhaust gas of the gas turbine, an operation method thereof, and a remodeling method.

  International efforts to reduce the amount of carbon dioxide, one of the causes of global warming, to the atmosphere have led to the introduction of renewable energy power generation that does not emit carbon dioxide, such as solar and wind power, in each country. ing.

  Under such circumstances, electric power companies that have combined cycle power plants that use fossil fuels as natural gas as a measure to meet their carbon dioxide emission reduction targets in their own It is necessary to perform operations such as shutting down these plants and giving priority to the operation of high-efficiency and large-capacity plants.

  On the other hand, the combined cycle power plant also requires a load adjustment function for adjusting the supply and demand of the system power because of the high load following performance of the gas turbine. For example, in the case of solar power generation, the amount of power generation decreases in the early morning and evening when the altitude is low compared to the daytime when the solar altitude is high. In order to make up for the power shortage at this time, the combined power plant is required to be subjected to severe operation (peak operation) such as rapid start-up and load change twice in the morning and evening. In this regard, the operation of the combined power plant before the spread of solar power generation was a daily start / stop (morning start, evening stop), so the start and stop twice in the morning and evening has a higher rate of change than ever before. Start / stop is requested.

  As for the start-up control technology of the combined cycle power plant, there are prior arts shown in Patent Document 1 and Patent Document 2.

  In Patent Document 1, in a single-shaft combined (combined cycle) power plant that obtains steam from an exhaust heat recovery boiler using exhaust gas from a gas turbine, exhaust heat recovery is used as auxiliary steam necessary for cooling the low-pressure steam turbine at startup. Steam generated from the low pressure drum of the boiler is used.

  Further, in Patent Document 2, in a combined cycle power plant that obtains steam from an exhaust heat recovery boiler using exhaust gas from a gas turbine, steam generated in a waste incinerator is used for cooling of the steam turbine at startup and for heat retention during standby.

  As shown in Patent Documents 1 and 2, which are prior arts, a method of supplying auxiliary steam to a steam turbine, which is a large structure, is generally used when starting a combined cycle power plant. The auxiliary steam is used to relieve the thermal stress of the rotating part (rotor blade) of the steam turbine or to reduce the difference in thermal elongation between the rotating part (drive shaft) and the stationary part (casing). As the auxiliary steam, either steam generated from the combined cycle power plant main body or steam generated from the outside of the combined cycle power plant is used.

JP 2002-129909 A JP 08-246814 A

  However, when the load adjustment operation is performed in the early morning or evening or when the power generation amount of solar power generation is reduced as described above, it is necessary to further shorten the startup time of the combined cycle power plant. This means that, for example, when a combined cycle power plant is newly installed, startup and operation at a predetermined speed change rate or load change rate are assumed. This means that startup or operation at a rate or load change rate is required.

  As a result, even if the gas turbine can be operated at a higher rate of change, in the exhaust gas utilization side equipment (exhaust heat recovery boiler and steam turbine) that uses the gas turbine exhaust gas, the gas turbine exhaust gas temperature further increases. A new problem arises as the temperature increases or the rate of temperature change is large.

  For example, when considering an exhaust heat recovery boiler as an exhaust gas utilization side device, there is a possibility that the exhaust gas from the exhaust heat recovery boiler is generated by the turbine exhaust gas whose temperature rises rapidly, and the heat exchanger is damaged. In particular, regenerative heat exchangers that reheat the steam turbine exhaust are concerned about air heating due to heating before the reheat steam is ventilated.

  Further, regarding the steam turbine as the exhaust gas utilization side device, when priority is given to load followability, it may occur that the gas turbine is rapidly started in advance without waiting for the generation of auxiliary steam to the steam turbine. At this time, as a result of starting without supplying sufficient steam to the rotating part (rotor) or stationary part (casing) of the steam turbine, the main part is brought into contact with the rotating part and the stationary part due to thermal fatigue or differential thermal expansion of the turbine rotor blades. May be damaged.

  From the above, the problem to be solved by the present invention is to solve the thermal problem in the gas turbine exhaust gas utilization side system at the time of rapid start / stop of the combined cycle power plant, specifically the thermal stress of the steam turbine.・ To reduce the difference in thermal expansion or to prevent the heat exchanger in the exhaust heat recovery boiler from being blown.

  In view of the above-mentioned problems, the present invention is driven by a gas turbine, an exhaust heat recovery boiler that generates at least high-pressure and low-pressure steam from the exhaust gas of the gas turbine, and high-pressure and low-pressure steam from the exhaust heat recovery boiler. A combined cycle power generation plant configured to generate power by being driven by the gas turbine and at least the gas turbine of the gas turbine and the steam turbine, wherein the low pressure steam drum generating the low pressure steam of the exhaust heat recovery boiler has a low pressure A combined cycle power plant comprising a low pressure steam header for introducing steam generated in a steam drum, wherein the steam stored in the low pressure steam header is used as auxiliary steam in the combined cycle power plant before the generation of high pressure steam is established . "

  Further, in the present invention, “a gas turbine, an exhaust heat recovery boiler that generates at least high-pressure and low-pressure steam from the exhaust gas of the gas turbine, and a steam turbine driven by high-pressure and low-pressure steam from the exhaust heat recovery boiler; A modified method of a combined cycle power plant composed of a generator that is connected to the same shaft and driven to generate power by being connected to the gas turbine and the steam turbine, the same shaft, a drive shaft that connects the gas turbine and the generator, Divided into two shafts of the drive shaft of the steam turbine, the low-pressure steam drum that generates the low-pressure steam of the exhaust heat recovery boiler is equipped with a low-pressure steam header that introduces the steam generated in the low-pressure steam drum, and stored in the low-pressure steam header The steam is used as auxiliary steam in a combined cycle power plant before the establishment of high-pressure steam in an exhaust heat recovery boiler Remodeling method of emission bind cycle power plant. Is obtained by a ".

  Further, in the present invention, “a gas turbine, an exhaust heat recovery boiler that generates at least high-pressure and low-pressure steam from the exhaust gas of the gas turbine, and a steam turbine driven by high-pressure and low-pressure steam from the exhaust heat recovery boiler; A combined cycle power plant operating method comprising a gas turbine and a generator that generates power by being driven by at least the gas turbine of the steam turbine, the steam generated by a low-pressure steam drum that generates low-pressure steam of an exhaust heat recovery boiler Is stored in a low-pressure steam header, and the stored steam is used as auxiliary steam in the combined cycle power plant before the generation of high-pressure steam is established.

  According to the combined cycle power plant according to the present invention, thermal problems in the gas turbine exhaust gas utilization side system at the time of rapid start / stop of the plant can be solved.

The figure which shows the structural example of the combined cycle power plant in Example 1. FIG. The figure which shows the schematic structural example of the combined cycle power plant control apparatus by a present Example. The figure which shows an example of the gas turbine load characteristic b1 at the time of starting the gas turbine 1 rapidly. The figure which shows the steam pressure characteristic of the low pressure steam drum at the time of starting the gas turbine 1 rapidly. The figure which shows the steam flow rate to the low voltage | pressure superheater of the combined cycle power plant by a present Example. The figure which shows the steam flow rate from the low pressure steam header of the combined cycle power plant by a present Example to a reheater. The figure which shows the steam flow from the low pressure steam header of the combined cycle power plant by a present Example to a steam turbine drive shaft. The figure which shows the steam flow rate from the low pressure steam header of the combined cycle power plant by a present Example to a high pressure steam turbine. The figure which shows the structural example of the combined cycle power plant in Example 2. FIG. The figure which shows the structural example of the combined cycle power plant in Example 3. FIG.

  A schematic configuration of a combined cycle power plant according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration example of a combined cycle power plant in the first embodiment.

  A combined cycle power plant 100 shown in FIG. 1 includes a gas turbine 1, a steam turbine 2, a generator 3, and an exhaust heat recovery boiler 5 as main components. At this time, the gas turbine 1, the steam turbine 2, and the generator 3 are connected by the drive shaft 4.

  Turbine exhaust gas 35 from the gas turbine 1 flows into the exhaust duct 21 of the exhaust heat recovery boiler 5 and heats the feed water pumped by the feed water pump 16 by a heat exchanger group. Steam generated by heating in the heat exchanger group is supplied to the steam turbine 2.

  In the embodiment of FIG. 1, the heat exchanger group in the exhaust heat recovery boiler 5 constitutes a low pressure system, an intermediate pressure system, and a high pressure system, and the heat exchanger group of each pressure system has a so-called drum boiler configuration. As a result, low-pressure steam, medium-pressure steam, and high-pressure steam are generated.

  In FIG. 1, in the low pressure system, the feed water from the feed water pump 16 a is heated by the low pressure feed water heater 22 and then supplied to the low pressure drum 32. In the low-pressure drum 32, the heated feed water is evaporated and boiled by the low-pressure boiler 23, then superheated by the low-pressure superheater 24 to form low-pressure steam, and the medium-low pressure turbine 15 is driven via the low-pressure steam pipe 20.

  Further, in the intermediate pressure system, water supplied from the water supply pump 16 b is heated by the intermediate pressure water heater 25 and then supplied to the intermediate pressure drum 33. Further, the intermediate pressure drum 323 evaporates and boiles the heated feed water in the intermediate pressure boiler 26 and then superheats it in the intermediate pressure superheater 27 to produce intermediate pressure steam.

  In FIG. 1, the exhaust from the high-pressure steam turbine 14 is merged at the outlet of the medium-pressure superheater 27 through the reheat steam pipe 18, reheated by the reheater 30, and then passed through the medium-pressure steam pipe 19 to the medium-low pressure turbine. 15 is driven. An exhaust heat recovery boiler that reheats the exhaust from the high-pressure steam turbine 14 is called a reheat type.

  Further, in the high pressure system, the feed water from the feed pump 16 c is heated by the high pressure feed water heater 28 and then supplied to the high pressure drum 34. In the high-pressure drum 34, the heated feed water is evaporated and boiled by the high-pressure boiler 29, then superheated by the high-pressure superheater 31 to form high-pressure steam, and the high-pressure turbine 14 is driven via the main steam pipe 17.

  In the combined cycle power plant of FIG. 1, the gas turbine 1, the high pressure turbine 14, and the medium / low pressure turbine 15 are connected by the drive shaft 4, and therefore the total value of the power generation output in each turbine becomes the power generation output of the plant. .

  1, the present invention further includes a low-pressure steam header 6 at the outlet of the low-pressure boiler 32, and the steam generated in the low-pressure boiler 32 is supplied to the low-pressure steam header 6 and the low-pressure superheater 24. Branch to

  Here, in the present invention, the reason why the steam generated in the low-pressure boiler 32 is stored in the low-pressure steam header 6 is that the low-pressure, medium-pressure, and high-pressure heat exchanger groups in the exhaust heat recovery boiler when the gas turbine is started. Among them, steam is generated at the earliest time in the low pressure system, and it is used as auxiliary steam necessary for protection and function maintenance of exhaust gas utilization side equipment (exhaust heat recovery boiler and steam turbine) using the steam established in the shortest time By being available.

  The auxiliary steam secured in the low-pressure steam header 6 is used in the following places as auxiliary steam necessary for protection and function maintenance of the exhaust gas utilization side equipment (exhaust heat recovery boiler and steam turbine).

  The first point of use of auxiliary steam secured in the low-pressure steam header 6 is used for the purpose of protecting the reheater 30. For this reason, a reheater steam supply pipe 7 for supplying the steam stored in the low pressure steam header 6 to the reheat steam pipe 18 is provided. Furthermore, a steam flow rate adjusting valve 8 is provided as means for increasing or decreasing the flow rate of the steam flowing through the reheater steam supply pipe 7. When the steam flow control valve 8 is opened, steam flows from the low pressure boiler 32 to the reheater 30 through the low pressure steam header 6. This makes it possible to prevent the reheater 30 from being blown when the gas turbine 1 starts up rapidly.

  When the steam flow rate control valve 8 is closed, the steam supply from the low-pressure steam header 6 is stopped, so that the steam flow is equivalent to that of a normal combined cycle power plant.

  The second point of auxiliary steam utilization secured in the low-pressure steam header 6 is used for the drive shaft seal steam for maintaining the function of the steam turbine. For this reason, a drive shaft auxiliary steam pipe 9 for supplying the steam stored in the low pressure steam header 6 to the steam turbine side drive shaft is provided. Furthermore, a steam flow rate adjusting valve 10 is provided as means for increasing or decreasing the flow rate of the steam flowing through the drive shaft auxiliary steam pipe 9. When the steam flow control valve 10 is opened, steam flows from the low pressure boiler 32 through the low pressure steam header 6 to the drive shaft 4 bearing portion of the steam turbine 2. Thereby, when the gas turbine 1 starts up rapidly, the steam turbine 2 is preheated, and it becomes possible to reduce the thermal expansion difference of the steam turbine.

  When the steam flow control valve 10 is closed, the steam supply from the low-pressure steam header 6 is stopped, so that the steam flow is equivalent to that of a normal combined cycle power plant. Although not shown, auxiliary steam for preheating the steam turbine is supplied to the combined cycle power plant in this embodiment, and when the steam flow control valve 10 is closed, the combined steam power plant is conventionally combined with the steam turbine. As with the cycle power plant, the steam turbine is preheated.

  The third point of auxiliary steam utilization secured in the low-pressure steam header 6 is used for steam turbine preheating steam for maintaining the function of the steam turbine. For this reason, the steam turbine preheating steam piping 36 which supplies the steam stored in the low pressure steam header 6 to the high pressure turbine 14 is provided. Furthermore, a steam flow rate adjusting valve 37 is provided as means for increasing or decreasing the flow rate of the steam flowing through the steam turbine preheating steam pipe 36. When the steam flow control valve 10 is opened, steam flows from the low pressure boiler 32 through the low pressure steam header 6 to the steam turbine 14. As a result, when the gas turbine 1 starts up rapidly, the rotor blades of the steam turbine 2, particularly the steam turbine 14, are preheated, and the thermal stress of the steam turbine can be reduced.

  When the steam flow control valve 37 is closed, the steam supply from the low-pressure steam header 6 is stopped, so that the steam flow is equivalent to that of a normal combined cycle power plant. Although not shown, auxiliary steam for preheating the steam turbine is supplied to the combined cycle power plant in the present embodiment, and when the steam flow rate control valve 37 is closed, the conventional combined power is supplied to the steam turbine. As with the cycle power plant, the steam turbine is preheated.

  The structural example of the control apparatus of the combined cycle power plant by a present Example is demonstrated using FIG.

  The control apparatus for the combined cycle power plant 100 according to the present invention includes an existing combined cycle power plant control apparatus 101 and a low pressure steam header steam flow control apparatus 102.

  The combined cycle power plant control apparatus 101 receives a power generation command LD from a central power supply command station (medium supply), and receives a plant measurement value Y (for example, power generation output, turbine exhaust gas temperature, high / mid / low pressure drum water level, turbine rotation) The operation amount X (for example, a fuel flow rate adjusting valve, a turbine adjusting valve opening degree, etc.) is calculated based on the numerical value, and operation control is performed so that the plant power generation output follows the power generation command LD.

  On the other hand, the low-pressure steam header steam flow control device 102 of the present invention includes a low-pressure steam header steam overall control means 103, a reheater side steam flow rate adjustment valve control means 104, a drive shaft side steam flow rate adjustment valve control means 105, a steam turbine steam. The flow control valve adjusting means 106 is configured.

  The low-pressure steam header steam supervising control means 103 receives the gas turbine load LDG from the combined cycle power plant control apparatus 101, the reheater steam temperature set value TsD, the preheating state of the steam turbine according to the gas turbine load LDG at the time of startup. The steam turbine casing inner / outer wall temperature difference set value ΔTmD and the steam turbine load set value LDS representing the start state of the steam turbine are calculated.

  Further, the reheater side steam flow rate adjusting valve control means 104 inputs the reheater steam temperature measurement value Ts from the combined cycle power plant 100 and reheater side so that the measurement value Ts matches the set value TsD. The opening degree command Cv1 of the steam flow rate adjusting valve is calculated.

  Further, the drive shaft side steam flow rate adjusting valve control means 105 inputs the measured value of the steam turbine casing inner / outer wall temperature difference ΔTm from the combined cycle power plant 100 and drives the drive shaft side so that the measured value ΔTm matches the set value ΔTmD. The opening degree command Cv2 of the steam flow rate adjusting valve is calculated.

  Furthermore, the steam turbine steam flow rate adjustment valve control means 106 calculates the opening degree command Cv3 of the steam flow rate adjustment valve 37 based on the set value LDS.

  The steam turbine steam flow rate adjusting valve control means 106 does not input a measured value from the combined cycle power plant 100 because the steam turbine blade temperature cannot be directly measured. In the present invention, it is assumed that the moving blade temperature of the steam turbine is determined according to the steam turbine load, and the steam flow rate to the steam turbine is adjusted from the steam turbine set value LDS. Alternatively, the steam flow rate may be determined using this value.

  As can be seen from FIG. 2, the low-pressure steam header flow control device 102 controls the amount of steam flowing out from the low-pressure steam header 6 and operates independently of the combined cycle power plant control device 101. Therefore, the low-pressure steam header steam flow control device 102 can be additionally installed in an existing combined cycle power plant.

  The plant starting operation characteristics of the combined cycle power plant control apparatus according to this embodiment will be described with reference to FIGS.

  FIG. 3 shows an example of the gas turbine load characteristic b1 (corresponding to the LDG in FIG. 2) when the gas turbine 1 is rapidly started in the combined cycle power plant 100. The time including the speed-up stage after starting the gas turbine is shown on the horizontal axis, and the gas turbine load at each time is shown on the vertical axis. This figure also shows the gas turbine load characteristic a1 of the conventional combined cycle power plant, but the gas turbine has a startup time (gas turbine load characteristic a1) of 1.5 hours in the conventional combined cycle power plant. This is intended to complete the start-up (gas turbine load characteristic b1) in about 30 minutes during rapid start-up.

  FIG. 4 shows the steam pressure characteristics of the low-pressure steam drum when the gas turbine 1 is rapidly started. The horizontal axis indicates the time including the speed-up stage after the gas turbine is started, and the vertical axis indicates the steam pressure of the low-pressure steam drum at each time. The steam pressure of the low-pressure steam drum increases as the gas turbine load increases (that is, the gas turbine exhaust temperature increases). The low pressure drum pressure when the gas turbine is rapidly started in the present invention is shown as b2, and the conventional low pressure drum pressure is shown as a2.

  High temperature exhaust gas flows into the exhaust heat recovery boiler due to the exhaust gas temperature rise of the gas turbine. The high-pressure, medium-pressure, and low-pressure heat exchangers are temporarily blown by high-temperature exhaust gas, but the high-pressure superheater and medium-pressure superheat are generated by the steam generated in the high-pressure steam drum, medium-pressure steam drum, and low-pressure steam drum. Steam flows into the inside of the heater and the low-pressure superheater. However, with regard to the reheater through which the steam from the high pressure turbine passes, the inflowing steam is only the steam from the intermediate pressure superheater, so that the steam is insufficient and is in an empty state.

  FIG. 5 shows the steam flow rate to the low-pressure superheater of the combined cycle power plant according to this embodiment. The horizontal axis represents the time including the acceleration stage after the gas turbine was started, and the vertical axis represents the steam flow rate to the low-pressure superheater at each time. b3 shows the steam flow rate to the low-pressure superheater when the gas turbine is rapidly started in the present invention.

  FIG. 6 shows the steam flow rate from the low-pressure steam header of the combined cycle power plant according to this embodiment to the reheater. The horizontal axis represents the time including the speed-up stage after starting the gas turbine, and the vertical axis represents the steam temperature at the reheater outlet at each time. In the figure, b4 is the steam flow rate when the steam temperature at the outlet of the reheater is measured and controlled so that the measured value matches the set value. As shown, the steam flow rate increases at the start of the gas turbine to prevent reheater airing and then decreases. This is because the steam flow rate from the intermediate pressure steam drum increases.

  FIG. 7 shows the steam flow rate from the low-pressure steam header of the combined cycle power plant according to this embodiment to the steam turbine drive shaft. The time including the speed-up stage after starting the gas turbine is shown on the horizontal axis, and the steam flow rate to the steam turbine drive shaft at each time is shown on the vertical axis. In the figure, b5 represents the steam flow rate when the temperature difference between the inner and outer walls of the steam turbine casing is measured and controlled so that the measured value matches the set value. As shown, the steam flow rate increases at the start of the gas turbine and then decreases to mitigate the thermal stress of the turbine rotor and the differential thermal expansion between the rotor and casing. This is because the flow rate of the mole steam from the high-pressure, medium-pressure, and low-pressure steam flowing into the steam turbine is increased and used for preheating the steam turbine drive shaft.

  FIG. 8 shows the steam flow rate from the low-pressure steam header of the combined cycle power plant according to this embodiment to the high-pressure steam turbine. The time including the speed-up stage after starting the gas turbine is shown on the horizontal axis, and the steam flow rate to the high-pressure steam turbine at each time is shown on the vertical axis. In the figure, b6 is the steam flow when the steam flow to the high-pressure steam turbine is set and controlled based on the steam turbine load setting. In this embodiment, the steam flow rate is maximized at the initial stage of the steam turbine load, and then gradually decreased. This is intended to preheat and relieve the stress on the turbine blades by supplying low-temperature and low-pressure steam to the turbine blades at the beginning of startup.

  As described above, FIGS. 3 to 8 show the time change of various amounts on the real time axis when the gas turbine is started at high speed. According to this, when the gas turbine is started in 30 minutes as shown in FIG. In addition, low-pressure steam is generated from about 7 to 8 minutes, and this can be used as auxiliary steam necessary for protection and function maintenance of exhaust gas utilization side equipment (exhaust heat recovery boiler and steam turbine).

  As shown in FIGS. 6, 7, and 8, it is sufficient that auxiliary steam necessary for protecting and maintaining the functions of the exhaust gas utilization side devices (exhaust heat recovery boiler and steam turbine) can be ensured in a short time at the start of startup. In FIG. 6, low-pressure steam may be supplied until reheat steam is generated, in FIG. 7, it may be supplied until steam is established in the original bearing seal steam supply system, and in FIG. It only needs to be able to supply until steam is established.

  The low-pressure steam header flow rate control device 102 starts supplying auxiliary steam at an appropriate timing, stops supplying it, and performs control to optimize the supply amount at each time. In each auxiliary steam usage destination, when the original steam is established, the steam flow rate control valves 8, 10, 37 are closed to prevent backflow.

  A combined cycle power plant according to Embodiment 2 of the present invention will be described with reference to FIG.

  The difference between the first embodiment and the second embodiment of the combined cycle power plant of the present invention is that the gas turbine 1 drives the generator 3 via the drive shaft 4 and the steam turbine 2 is driven by another drive shaft 40. The plant shaft is cut and remodeled.

  When the gas turbine 1 is rapidly activated in the second embodiment, the gas turbine 1 drives the generator 3. Therefore, the power generation output of the entire plant is equal to the power generation output of the gas turbine 2. Since the load to be driven by the gas turbine 2 is only the generator 3 at the time of starting the plant, the plant can be started more rapidly.

  On the other hand, since the high-temperature gas due to rapid activation flows into the exhaust heat recovery boiler 5, the steam stored in the low-pressure steam header 6 is supplied to the reheat steam pipe 18 to prevent the reheater 30 from being aired.

  Further, the steam stored in the low-pressure steam header 6 is supplied to the steam turbine side drive shaft, thereby reducing the thermal stress and the difference in thermal elongation of the steam turbine.

  Since the steam turbine 2 is not connected to the generator, the steam turbine 2 is a device that consumes the energy of the steam by the work of the turbine.

  A combined cycle power plant according to Example 3 of the present invention will be described with reference to FIG.

  The difference between the second and third embodiments of the combined cycle power plant of the present invention is that the gas turbine 1 drives the generator 3 via the drive shaft 4 and the steam turbine 2 passes the other drive shaft 40. The plant shaft is cut and a generator is added to drive one generator 41.

  When the gas turbine 1 is rapidly activated in the third embodiment, the gas turbine 1 drives the generator 3. Therefore, the power generation output of the entire gas turbine plant is equal to the power generation output of the gas turbine 2. Since the load to be driven by the gas turbine 2 is only the generator 3 at the time of starting the plant, the plant can be started more rapidly.

  On the other hand, since the high-temperature gas due to rapid activation flows into the exhaust heat recovery boiler 5, the steam stored in the low-pressure steam header 6 is supplied to the reheat steam pipe 18 to prevent the reheater 30 from being aired.

  Further, the steam stored in the low-pressure steam header 6 is supplied to the steam turbine side drive shaft, thereby reducing the thermal stress and the difference in thermal elongation of the steam turbine.

  Since another generator 41 is connected to the steam turbine 2, power generation according to the amount of steam from the exhaust heat recovery boiler 5 becomes possible.

  The present invention is not limited to the embodiments described above. In each embodiment, the example in which the main engines are arranged in the order of the gas turbine 1, the generator 3, and the steam turbine 2 has been described. For example, the rotating shafts are connected in the order of the generator 4, the gas turbine 1, and the steam turbine 2. In such a case, the rotating shaft may be separated between the gas turbine 1 and the steam turbine 2 and a new generator 41 may be installed on the rotating shaft on the steam turbine 2 side.

  The exhaust heat recovery boiler 5 of the present invention has three types of boilers of high pressure, medium pressure, and low pressure, and is configured as a reheat triple pressure boiler that reheats the exhaust of the high pressure turbine. The present invention can also be applied to a non-reheated triple pressure boiler that does not reheat, or a non-reheated double pressure boiler that has two types of high and low pressure boilers. When the present invention is applied to a non-reheated triple pressure boiler or a non-reheated double pressure boiler, steam is supplied to a high-pressure superheater into which high-temperature exhaust gas flows in with rapid start-up of the gas turbine. It becomes possible to reduce the thermal stress of the high-pressure superheater due to.

  According to the embodiment of the present invention, it is possible to prevent the reheater and the superheater from becoming empty due to the high-temperature gas flowing into the exhaust heat recovery boiler when the gas turbine is rapidly started.

  Furthermore, according to the embodiment of the present invention, it is possible to reduce the thermal stress and the thermal expansion difference of the steam turbine generated by the high-temperature steam flowing into the steam turbine when the gas turbine is rapidly started.

  In addition to the combined cycle power plant for power generation, it can be used as an apparatus configuration and control method for industrial cogeneration plants and micro combined cycle power plants.

1: Gas turbine 2: Steam turbine 3: Generator 4: Drive shaft 5: Waste heat recovery boiler 6: Low-pressure steam header 7: Reheater steam supply pipe 8: Steam flow control valve 9: Drive shaft auxiliary steam pipe 10: Steam flow control valve 11: Compressor 12: Combustor 13: Turbine 14: High pressure turbine 15: Medium / low pressure turbine 16: Feed water pump 17: High pressure steam pipe 18: Reheat steam pipe 19: Medium pressure steam pipe 20: Low pressure steam pipe 21: Exhaust duct 22: Low pressure feed water heater 23: Low pressure boiler 24: Low pressure superheater 25: Medium pressure feed water heater 26: Medium pressure boiler 27: Medium pressure superheater 28: High pressure feed water heater 29: High pressure boiler 30: Re Heater 31: High pressure superheater 32: Low pressure drum 33: Medium pressure drum 34: High pressure drum 35: Turbine exhaust gas 36: Steam turbine preheating steam piping 37: Steam flow rate adjustment valve 40: Another drive shaft 41: Generator 10 : Combined cycle power plant 101 of the present invention: Combined cycle power plant control device 102: Low pressure steam header steam flow control device 103 of the present invention: Low pressure steam header steam overall control means 104: Reheater side steam flow rate control valve control means 105 : Driving shaft side steam flow rate adjusting valve control means 106: Steam turbine steam flow rate adjusting valve control means

Claims (13)

A gas turbine, an exhaust heat recovery boiler that generates at least high-pressure and low-pressure steam from the exhaust gas of the gas turbine, a steam turbine driven by high-pressure and low-pressure steam from the exhaust heat recovery boiler, the gas turbine, A combined cycle power plant comprising a generator that generates power by being driven by at least the gas turbine of a steam turbine,
The low-pressure steam drum that generates low-pressure steam of the exhaust heat recovery boiler is provided with a low-pressure steam header that introduces steam generated in the low-pressure steam drum, and the steam stored in the low-pressure steam header before the generation of the high-pressure steam is established. A combined cycle power plant characterized by being used as auxiliary steam in a combined cycle power plant. The combined cycle power plant according to claim 1,
A combined cycle power plant comprising a reheater steam supply pipe for supplying steam stored in the low pressure steam header to a reheater of the exhaust heat recovery boiler. The combined cycle power plant according to claim 1 or 2,
A combined cycle power plant comprising a drive shaft auxiliary steam pipe for supplying steam stored in the low-pressure steam header to a bearing of the steam turbine. The combined cycle power plant according to any one of claims 1 to 3,
A combined cycle power plant comprising a high-pressure turbine preheating steam pipe for supplying steam stored in the low-pressure steam header to a high-pressure turbine of the steam turbine. The combined cycle power plant according to any one of claims 1 to 4,
A combined cycle power plant comprising two shafts, a drive shaft connecting the gas turbine and the generator, and a drive shaft of the steam turbine. The combined cycle power plant according to any one of claims 1 to 4,
The combined cycle power plant, wherein the gas turbine, the generator, and the steam turbine are connected on the same shaft. The combined cycle power plant according to claim 5,
A combined cycle power plant, wherein a generator is connected to the drive shaft on the steam turbine side. A gas turbine, an exhaust heat recovery boiler that generates at least high-pressure and low-pressure steam from the exhaust gas of the gas turbine, a steam turbine driven by high-pressure and low-pressure steam from the exhaust heat recovery boiler, the gas turbine, A method for remodeling a combined cycle power plant composed of a generator that is connected to the same shaft to a steam turbine to generate electric power,
The same shaft is divided into two shafts, a drive shaft connecting the gas turbine and the generator, and a drive shaft of the steam turbine,
The low-pressure steam drum that generates the low-pressure steam of the exhaust heat recovery boiler is equipped with a low-pressure steam header that introduces the steam generated in the low-pressure steam drum, and the steam stored in the low-pressure steam header before the high-pressure steam of the exhaust heat recovery boiler is established The combined cycle power plant is used as auxiliary steam in the combined cycle power plant. A method for remodeling a combined cycle power plant according to claim 8,
A method for remodeling a combined cycle power plant, wherein a generator is additionally connected to the drive shaft on the steam turbine side. A gas turbine, an exhaust heat recovery boiler that generates at least high-pressure and low-pressure steam from the exhaust gas of the gas turbine, a steam turbine driven by high-pressure and low-pressure steam from the exhaust heat recovery boiler, the gas turbine, A method for operating a combined cycle power plant comprising a generator that generates power by being driven by at least the gas turbine of a steam turbine,
Steam generated by a low-pressure steam drum that generates low-pressure steam of the exhaust heat recovery boiler is stored in a low-pressure steam header, and the stored steam is used as auxiliary steam in the combined cycle power plant before the generation of the high-pressure steam is established. A method for operating a combined cycle power plant. A method for operating a combined cycle power plant according to claim 10,
A reheater steam supply pipe for supplying the steam stored in the low pressure steam header to the reheater of the exhaust heat recovery boiler is provided. A method for operating a combined cycle power plant characterized by determining a steam flow rate. A method for operating a combined cycle power plant according to claim 10,
A drive shaft auxiliary steam pipe for supplying the steam stored in the low-pressure steam header to the bearing of the steam turbine is provided, and the steam flow rate to the bearing is determined based on the measured value of the temperature difference between the inner and outer walls of the steam turbine. A method for operating a combined cycle power plant. A method for operating a combined cycle power plant according to claim 10,
A high-pressure turbine preheating steam pipe for supplying the steam stored in the low-pressure steam header to the high-pressure turbine of the steam turbine is provided, and a steam flow rate to be supplied to the high-pressure turbine is determined based on a start characteristic of the steam turbine. Operation method of combined cycle power plant.

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