JP2018135837A - Steam turbine plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a steam turbine plant having higher efficiency than the conventional one by effectively utilizing thermal energy in a system. SOLUTION: A feed water heater 33 dedicated to a stationary blade drain provided in a condensate line S1 for supplying water P2 generated by a condenser 3 to a boiler 1, a hollow portion of the stationary blade of a steam turbine 2, and a feed water heater. It is provided with a stationary blade drain extraction line S3 for connecting the vessel 33 and feeding the static blade drain P3 of moisture and steam taken in from the outer surface of the stationary blade to the hollow portion through the moisture intake port to the feed water heater 33. , The feed water heater 33 is configured to heat the water P2 of the condensate line S1 by utilizing the heat energy of the stationary blade drain P3. [Selection diagram] Fig. 1

Description

  The present invention relates to a steam turbine plant.

  Conventionally, a steam turbine plant has, for example, a boiler, a steam turbine driven by steam from the boiler (a high pressure steam turbine, an intermediate pressure steam turbine, a low pressure steam turbine, etc.), a generator that generates power by driving each turbine, and a low pressure The steam generator is configured to include a condenser that returns the steam exhausted from the steam turbine to water and supplies it to the boiler, and a control device that controls these devices.

  In addition, between the condenser and the boiler, for example, a feed water heater that heats condenser water by heat exchange with steam extracted from the steam turbine, steam leakage from the steam turbine, and external air to the steam turbine A ground steam recovery condensing device (GSC) is provided for recovering steam heat and condensate in the grand seal steam system to prevent inflow.

  On the other hand, the steam turbine includes a rotor and a stator, and the rotor is radially arranged by projecting from the outer periphery of each rotor disk in the axial direction to the radial direction in the axial center. And a plurality of moving blades.

  The stator is disposed so as to surround the rotor, and includes a casing including a casing main body that partitions the inside of the turbine from the outside, a blade ring that is integrally supported by an inner peripheral portion of the casing main body, and a plurality of stationary blades And.

  In addition, a plurality of moving blades of one rotor disk and the corresponding stationary blades constitute one “stage”, and the steam turbine is provided with multiple stages of moving blades and stationary blades. Further, the plurality of stages are configured such that the blade heights of the rotor blades and the stationary blades (the blade lengths in a direction substantially orthogonal to the rotor) increase as the steam flows from the upstream side to the downstream side. .

  In the steam turbine configured in this way, steam is supplied into the casing from one end in the axial direction and flows to the other end in the axial direction, and kinetic energy is generated by the pressure drop at the stationary blades of each stage, and this is moved. It is converted into rotational torque by the blade, and the rotor can be rotated around the axis.

  Here, in the steam turbine (inside the casing), energy decreases toward the downstream stage, and for example, wetness occurs in the final stage of the low-pressure turbine (inside the final blade group). This wetness (moisture) of steam not only causes energy loss to the steam turbine in various forms, but also becomes water droplets, which may erode and damage the blades. In particular, there are cases where coarse water droplets adhering to the surface of the stationary blade are scattered from the trailing edge of the stationary blade and collide with the moving blade, thereby causing not only energy loss but also damage to the moving blade.

  On the other hand, in Patent Document 1, a stationary blade is formed with a hollow structure, and a slit is provided through the outer surface to the inner surface (from the surface of the stationary blade to the inner surface of the hollow portion) to communicate the steam flow path and the hollow portion. A technique is disclosed in which a stationary blade is formed and moisture such as water droplets adhering to the outer surface of the stationary blade is taken into the hollow portion through this slit to prevent energy loss and blade damage.

Japanese Patent Publication No.49-9522

  However, if moisture such as water droplets adhering to the outer surface of the stationary blade is taken into the hollow portion through the slit and the water is discharged out of the steam turbine system as described above, the steam is removed from the system through the slit together with the moisture. There is a problem that the water leaks, such as water droplets, and the heat energy of the leaking steam is discharged without being used, resulting in a reduction in efficiency of the steam turbine plant.

  The steam turbine plant of the present invention includes a boiler, a steam turbine driven by steam from the boiler, and a condenser for returning steam discharged from the steam turbine to water and supplying the steam to the boiler. A steam turbine plant, wherein the steam turbine is rotatably provided around an axis, a casing disposed so as to surround the rotor to form a steam flow path, and the rotor integrally. A moving blade that is connected to the casing, and a stationary blade that is integrally connected to the casing and provided in the steam flow path, is formed in a hollow structure, penetrates from the outer surface to the inner surface, and the steam flow A stationary blade drain provided in a condensate line for supplying the boiler with water generated by the condenser, the stationary blade having an adhering moisture intake port communicating the passage and the hollow portion. The water supply heater for water, the hollow portion of the stationary blade and the water supply heater are connected, and the water and steam stationary blade drain taken into the hollow portion from the outer surface of the stationary blade through the attached moisture intake port is supplied to the water supply. A stationary blade drain extraction line for feeding to the heater, and the water heater uses the thermal energy of the stationary blade drain to heat the water in the condensate line.

  The steam turbine plant of the present invention is a ground steam recovery condensing device for recovering steam heat and condensate of a grand seal steam line for preventing external air from flowing into the steam turbine into the condensate line. It is desirable that a feed water heater dedicated to the stationary blade drain is provided closer to the condenser side of the condensate line than the ground steam recovery condensing device.

  More preferably, the steam turbine plant of the present invention is configured to send the stationary blade drain after being subjected to heat exchange by the feed water heater dedicated to the stationary blade drain to the condenser.

  The steam turbine plant of the present invention includes a stationary blade body in which the stationary blade has the hollow portion, an outer shroud disposed radially outside the axis of the stationary blade body, and the stationary blade body. An inner shroud disposed radially inward with respect to the axis, and an outer cavity formed by the outer shroud, an inner cavity formed by the inner shroud, and the hollow portion communicate with each other, More preferably, a stationary blade drain extraction line is connected to the outer cavity located below the axis.

  In the steam turbine plant of the present invention, it is possible to effectively utilize the thermal energy of these in the system without discharging moisture such as water droplets collected in the hollow portion of the stationary blade, and the steam leaking together with the moisture outside the system. it can. Thereby, compared with the past, it becomes possible to implement | achieve a highly efficient steam turbine plant.

It is a figure showing an example of a steam turbine plant concerning one embodiment of the present invention. It is a figure showing an example of a steam turbine concerning one embodiment of the present invention. It is sectional drawing to which the stationary blade, the moving blade, etc. of the steam turbine which concern on one Embodiment of this invention were expanded. It is sectional drawing of the stationary blade of the steam turbine which concerns on one Embodiment of this invention.

  Hereinafter, a steam turbine plant according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Here, in this embodiment, it demonstrates as what the steam turbine plant which concerns on this invention is a power plant etc., for example.

  As shown in FIG. 1, the steam turbine plant A of the present embodiment includes a boiler 1, a steam turbine 2 (high pressure steam turbine 2 a, low pressure steam turbine 2 b) driven by steam P 1 from the boiler 1, and each steam turbine 2. A generator (not shown) that generates electric power by driving the motor, a condenser 3 for returning the steam P1 discharged from the low-pressure steam turbine 2b to the water P2 and supplying it to the boiler 1, and controlling these devices And a control device (not shown).

  As shown in FIGS. 2 and 3, the steam turbine 2 includes a rotor 5 and a stator 6.

  The rotor 5 includes a plurality of rotor disks 7 arranged in parallel in the axis O1 direction, and a plurality of rotor blades 8 that are arranged radially from the outer periphery of each rotor disk 7 so as to protrude radially outward from the center of the axis O1. And.

  The stator 6 is disposed so as to surround the rotor 5, and the casing main body 9 that partitions the inside of the steam turbine A from the outside, and a blade ring (outer ring) that is integrally supported and supported by the inner peripheral portion of the casing main body 9. ) And a plurality of stationary blades disposed radially with a predetermined interval in the direction of the axis O1 (the flow direction of the steam P1). 12.

  A plurality of moving blades 8 provided on one rotor disk 7 and arranged in the circumferential direction constitute an annular moving blade group, and a plurality of stationary blades 12 arranged in the circumferential direction constitute an annular stationary blade group. One annular stage of the plurality of rotor blades 8 of one rotor disk 7 and one annular stator blade group adjacent to the upstream side of the steam flow direction of the annular rotor blade group constitute one “stage”. The steam turbine A is provided with multiple stages of moving blades 8 and stationary blades 12. Further, the plurality of stages are configured such that the blade heights of the rotor blades 8 and the stationary blades 12 (the blade lengths in the direction substantially perpendicular to the rotor 5) increase as the steam P1 flows from the upstream side to the downstream side. It is configured.

  The blade ring 10 is provided integrally with the inner peripheral portion of the casing body 9 and extends in the circumferential direction and is arranged in an annular shape.

  The stationary blade 12 is provided on the outer side in the radial direction, and extends to the inner side in the radial direction from the outer shroud 14 toward the rotor 5. The outer shroud 14 is connected to the blade ring 10 by welding or the like. The stator blade main body 16 and an inner shroud 17 provided integrally on the radially inner side (rotor 5 side) of the stator blade main body 16 are formed.

  The outer shrouds 14 of the plurality of stator blades 12 in the annular stator blade group each extend in the circumferential direction and form an outer cavity 18 between the blade ring 10 and the outer shroud 14. The outer cavities 18 of the plurality of stationary blades 12 communicate with each other in the circumferential direction, and are formed to have an annular shape as a whole.

  As shown in FIGS. 3 and 4, the stationary blade body 16 is formed by including a ventral member 20 that configures the ventral side and a back member 21 that configures the dorsal side. Further, the abdominal member 20 and the dorsal member 21 are metal plate-like members that are curved in different ways of warping, and the abdominal member 20 has an outer surface / surface that is a ventral surface of a stationary blade. The back side member 21 is warped and formed so that the outer surface / surface thereof is the back surface of the stationary blade 12.

  The stationary blade main body 16 is assembled with the ventral member 20 and the dorsal member 21 so as to form the ventral portion 22 and the dorsal portion 23 of the stationary blade 12, respectively. The end portions of the ventral member 20 and the back member 21 are welded together. Thereby, the stationary blade 12 is provided with the hollow part 25 extended along the blade height direction in the inside (between the inner surface / back surface of the ventral member 20 and the inner surface / back surface of the back member 21).

  Furthermore, in the steam turbine plant A of the present embodiment, for example, the stationary flow path 12 of the low-pressure steam turbine 2b and the stationary blade 12 on the downstream side of the low-pressure steam turbine 2b, and the steam flow path as the temperature and pressure of the steam P1 decrease. The portion of the stationary blade 12 (the stationary blade main body 16) where wetness can occur in the R is provided with an attached water intake port 30 penetrating from the outer surface to the inner surface at predetermined positions of the ventral side portion 22 and the back side portion 23. Is formed.

  The inner shroud 17 of each stationary blade 12 is integrally attached to the radially inner side (the rotor 5 side) of the stationary blade body 16, and the inner shrouds 17 of the plurality of stationary blades 12 extending in the circumferential direction and arranged in the circumferential direction are connected to each other. It is connected and formed into an annular shape. Further, a seal member is attached to an end portion of the inner shroud 17 in the direction of the axis O1, and the space between the inner shroud 17 and the end portion of the platform of the moving blade 8 adjacent in the direction of the axis O1 is sealed.

  Further, each inner shroud 17 includes two flanges 17a spaced in the direction of the axis O1 and projecting radially inward. One flange 17a is fitted to the seal ring holding ring 17b, and the other flange 17a is retained by the retainer. It is configured to be engaged with the seal ring holding ring 17b via the member 17c. The seal ring retaining ring 17b is formed in an annular shape continuously in the circumferential direction, and is configured by integrally providing a seal mechanism (labyrinth seal) on the inner peripheral portion.

  Further, an inner cavity 31 is formed by the inner partition wall 17d of each inner shroud 17, the seal ring holding ring 17b, and the retainer member 17c. The inner cavity 31 is formed in an annular shape by connecting the inner cavities 31 of the plurality of stationary blades 12 extending in the circumferential direction and arranged in the circumferential direction.

  In the present embodiment, the outer cavities 18 and the inner cavities 31 in adjacent stages are communicated with each other.

  Furthermore, in the steam turbine plant A of the present embodiment, the hollow portion 25 of the stationary blade 12, the outer cavity 18, and the inner cavity 31 communicate with each other. Thereby, for example, the stationary blade 12 of the low-pressure steam turbine 2b and the stationary blade 12 on the downstream side of the low-pressure steam turbine 2b are portions of the steam flow path R where the moisture can be generated as the temperature or pressure of the steam P1 decreases. In the stationary blade 12, the vapor flow path R and the hollow portion 25 communicate with each other through the adhering moisture intake port 30, and the outer cavity 18 and the inner cavity 31 communicate with each other through the adhering moisture intake port 30 and the hollow portion 25.

  On the other hand, as shown in FIG. 1, the steam turbine plant A of the present embodiment has a condensate between the condensate line S <b> 1 connecting the condenser 3 and the boiler 1, for example, by heat exchange with the exhaust of the steam turbine 2. A feed water heater for heating the water P2 collected by the vessel 3 to supply water to the boiler 1, a steam leakage from the steam turbine 2, and a ground seal steam line S 2 for preventing the inflow of external air to the steam turbine 2. A ground steam recovery condensing device (GSC) 32 is provided for recovering steam heat and condensate.

  Furthermore, the feed water heater (at least one feed water heater) of the present embodiment is a feed water heater 33 dedicated to the stationary blade drain, for example, the stationary blade 12 of the low pressure steam turbine 2b, and further downstream of the low pressure steam turbine 2b. The outer cavity 18 (and thus the inner cavity 31 and the hollow portion 25) of the stationary blade 12 and the stationary blade drain in a portion where the moisture can be generated in the steam flow path R as the temperature and pressure of the steam P1 decrease, such as the stationary blade 12. They are connected by an extraction line S3.

  Further, in the present embodiment, one end of the stationary blade drain extraction line S3 is connected to a portion of the outer cavity 18 located below the axis O1 of the steam turbine 2 (see FIG. 3). Further, in the present embodiment, the feed water heater 33 dedicated to the stationary blade drain is provided on the condenser 3 side, that is, on the upstream side of the ground steam recovery condensing device 32 of the condensate line S1.

  The boiler 1 is provided with not only water P2 collected by the condenser 3 but also a water supply line (not shown) for supplying water from the outside.

  In the steam turbine plant A of the present embodiment configured as described above, steam P1 generated by heating the water P2 with the boiler 1 is supplied to the steam turbine 2, and this steam P1 flows through the steam flow path R and moves. Power can be generated by a generator by rotating the blade 8 and thus the rotor 5.

  Further, the steam P1 after passing through the steam flow path R of the steam turbine 2 and provided for the rotation of the rotor 5 is discharged to the outside from a steam discharge port provided on the downstream side in the steam flow direction, and the condenser 3 , Cooled by heat exchange and returned to the water P2. This water P2 is sent from the condenser 3 to the boiler 1, and is circulated and fed to the steam turbine 2 as steam P1.

  Here, in the steam turbine 2 (inside the casing 11), the energy decreases toward the downstream stage, and for example, wetness occurs in the final stage (in the final blade group) of the low-pressure steam turbine 2b.

  In contrast, in the present embodiment, the adhering moisture intake port 30 is formed in the stationary blade 12 of the steam turbine 2, so that moisture such as water droplets adhering to the outer surface / surface of the stationary blade 12 is attached to the adhering moisture intake port. 30 is taken into the hollow portion 25 of the stationary blade 12, and is sent from the hollow portion 25 to the feed heater 33 dedicated to the stationary blade drain through the inner cavity 31, the outer cavity 18, and the stationary blade drain extraction line S3.

  Further, when moisture such as water droplets is taken into the hollow portion 25 from the adhering moisture intake port 30, the steam (accompanied leakage steam) P1 flowing through the steam flow path R is also taken into the hollow portion 25 together with the water droplets and the like. It is sent to the feed water heater 33 dedicated to the stationary blade drain through the blade drain extraction line S3. In this way, the accompanying leakage steam flows through the hollow portion 25, the inner cavity 31, the outer cavity 18, and the stationary blade drain extraction line S3. It is fed to the heater 33.

  Then, the stationary blade drain P3 of moisture such as water droplets and accompanying leakage steam is sent to the feed water heater 33, and the water P2 collected by the condenser 3 is heated using the heat of the stationary blade drain P3. Thereby, the energy at the time of producing | generating the steam P1 with the boiler 1 can be reduced.

  Further, in the present embodiment, steam or water (static vane drain after being subjected to heat exchange) P4 subjected to heat exchange by the feed water heater 33 or the ground steam recovery condensing device 32 is sent to the condenser 3. It is done.

  Therefore, in the steam turbine plant A of the present embodiment, moisture such as water droplets and the accompanying leaked steam drain P3 that have been discarded in the exhaust chamber and have not been effectively used are led to the feed water heater 33, and the condenser By exchanging heat with the water P2 extruded from 3, the thermal energy of the stationary blade drain P3 can be recovered and effectively used in the system.

  Therefore, according to the steam turbine plant A of the present embodiment, it is possible to improve the efficiency of the entire cycle as compared with the prior art and to realize a highly efficient steam turbine plant A.

  Further, the feed water heater 33 dedicated to the stationary blade drain is provided closer to the condenser 3 side of the condensate line S1 than the ground steam recovery condensing device 32, so that the heat of the steam in the gland seal steam line S2 is greater than that. The condensate P2 can be heated in advance by the stationary blade drain P3, which is at a low temperature and higher than the condensate. Thereby, the condensate P2 can be efficiently heated and the energy of the boiler 1 can be effectively reduced.

  Further, the configuration is such that the stationary blade drain P4 that has been subjected to heat exchange by the feedwater heater 33 dedicated to the stationary blade drain is sent to the condenser 3, so that the boiler 1 can further include the stationary blade drain P3 as water. Can be sent more efficiently.

  Furthermore, the stationary blade 12 has a hollow portion 25 and the stationary blade main body 16, the outer shroud 14 disposed radially outside the axis O 1 of the stationary blade main body 16, and the axis O 1 of the stationary blade main body 16 as the center. An inner shroud 17 disposed radially inward, and an outer cavity 18 formed by the outer shroud 14, an inner cavity 31 formed by the inner shroud 17, and a hollow portion 25 communicate with each other to extract a stationary blade drain. Since the line S3 is connected to the outer cavity 18 positioned below the axis O1, the stator blade drain P3 can be efficiently collected using gravity and sent to the feed heater 33 dedicated to the stator blade drain. it can.

  As mentioned above, although one Embodiment of the steam turbine plant which concerns on this invention was described, this invention is not limited to said one Embodiment, In the range which does not deviate from the meaning, it can change suitably.

  For example, a feed water heater 33 dedicated to the stationary blade drain and a stationary blade drain extraction line S3 that sends the stationary blade drain P3 taken into the hollow portion 25 of the stationary blade 12 from the adhering moisture intake port 30 to the feed water heater 33 are provided. If it is, the other configurations need not be particularly limited.

  Further, the ground steam recovery condensing device 32 may be provided with the feed water heater 33 dedicated to the stationary blade drain closer to the condenser 3 side of the condensate line S1.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Steam turbine 2a High pressure steam turbine 2b Low pressure steam turbine 3 Condenser 5 Rotor 6 Stator 7 Rotor disk 8 Rotor blade 9 Casing main body 10 Blade ring (outer ring)
DESCRIPTION OF SYMBOLS 11 Casing 12 Stator blade 12a Front edge part 12b Rear edge part 14 Outer shroud 16 Outer blade body 17 Inner shroud 17a Flange 17b Seal ring holding ring 17c Retainer member 17d Inner partition wall 18 Outer cavity 20 Abdominal member 21 Back member 22 Abdomen Side part 23 Back side part 25 Hollow part 30 Adhesive water intake 31 Inner cavity 32 Ground steam recovery condensing device (GSC)
33 Stator blade drain dedicated feed water heater A Steam turbine plant O1 Axis P1 Steam P2 Condensate P3 Stator blade drain P4 Steam and water R Steam flow path S1 Condensate line S2 Ground seal steam line S3 Stator blade drain extraction line

Claims (4)

A steam turbine plant comprising: a boiler; a steam turbine driven by steam from the boiler; and a condenser for returning steam discharged from the steam turbine to water and supplying the steam to the boiler,
The steam turbine is provided so as to be rotatable around an axis, a casing disposed so as to surround the rotor to form a steam flow path, and a moving blade provided integrally with the rotor. And a stator blade integrally connected to the casing and provided in the steam flow path, and is formed in a hollow structure, and penetrates from the outer surface to the inner surface to connect the steam flow path and the hollow portion. Comprising the stationary blade formed with a moisture intake,
A feed water heater dedicated to a stationary blade drain provided in a condensate line that supplies water generated by the condenser to the boiler, and connects the hollow portion of the stationary blade and the feed water heater, and the outer surface of the stationary blade A stationary blade drain extraction line for feeding a stationary blade drain of moisture and steam taken into the hollow portion through the attached moisture intake port to the feed water heater,
A steam turbine plant configured to heat water of the condensate line by using heat energy of the stationary blade drain by the feed water heater. The condensate line is provided with a ground steam recovery condensate device for recovering steam heat and condensate in the gland seal steam line to prevent inflow of external air into the steam turbine,
The steam turbine plant according to claim 1, wherein a feed water heater dedicated to the stationary blade drain is provided closer to the condenser side of the condensate line than the ground steam recovery condensing device.   3. The steam turbine plant according to claim 1, wherein the steam turbine plant is configured to send a stationary blade drain after being subjected to heat exchange by a feed water heater dedicated to the stationary blade drain to the condenser. The stationary blade body in which the stationary blade has the hollow portion, the outer shroud disposed on the radially outer side centering on the axis of the stationary blade body, and the radially inner side of the stationary blade body centered on the axis. And an inner cavity formed by the outer shroud, an inner cavity formed by the inner shroud, and the hollow portion communicate with each other.
The steam turbine plant according to any one of claims 1 to 3, wherein the stationary blade drain extraction line is connected to the outer cavity located below the axis.

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