JP5651515B2 - Steam turbine power generation equipment - Google Patents

Description

  The present invention relates to a steam turbine power generation facility including a steam turbine and a turbine generator.

  Steam power generation equipment is a mechanism in which a steam turbine is driven by steam generated in a boiler, and this steam turbine rotates a generator to generate electricity. The steam after driving the steam turbine is condensed by a condenser. Condensate passes through pressure increase by a pump and heating by a feed water heater, and is supplied again to the boiler to become steam to drive the steam turbine. The steam power plant repeats these steps.

  Conventionally, the steam temperature condition of steam power generation equipment has been 600 ° C class, which is the highest temperature. In recent years, high efficiency of steam power generation facilities has been actively promoted against the background of fuel saving and environmental conservation. Along with this, a state-of-the-art high-temperature steam power generation system (A-USC) having a steam temperature of 700 ° C. has been widely studied.

  Steam turbines have high, medium and low pressure turbines. Some of the exhaust steam from these turbines, or the extracted steam extracted from the middle stage of the turbine exhaust, must be used as a heating source for the feed water heater or for driving a separate turbine different from the aforementioned turbine. There are many.

  When the steam temperature at the inlet of the steam turbine reaches 700 ° C., which is higher than the conventional one, the temperatures of the exhaust and extraction of the turbine also tend to increase. This increase in steam temperature makes it difficult to supply steam to the feed water heater or the separately installed turbine.

  When exhaust or bleed air whose temperature has been increased is used as a heating source for a feed water heater, a method of using heat resistant steel different from the conventional one as a material for the feed water heater is conceivable. However, this method is not preferable from the viewpoint of thermal stress and cost.

  In order to avoid this, for example, a cycle is known in which a part of the exhaust steam of a high-pressure turbine is once worked with a back extraction turbine and the feed water is heated with extraction with pressure and temperature sequentially reduced (for example, Patent Documents). 1-3).

JP-A-8-1000060 Japanese Patent Laid-Open No. 10-61413 U.S. Patent No. 20070137204

  A separate small steam turbine (hereinafter referred to as a “pump-driven turbine”) is mainly used to drive power generation and a feed water pump that boosts a feed water system to a boiler. Pump-driven turbines are often driven by steam obtained by branching off part of the exhaust from a medium-pressure turbine.

  However, in the case of A-USC, the temperature at the inlet and outlet of the steam turbine is higher than before. When supplying steam at a high temperature to the pump-driven turbine, a method of using heat-resistant steel different from the conventional one as a material for the pump-driven turbine is conceivable. However, this method is not preferable from the viewpoint of thermal stress and cost. Therefore, it is difficult to use the exhaust of the intermediate pressure turbine as a driving source of the pump driving turbine as in the prior art.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a steam turbine power generation facility capable of improving performance by increasing the steam conditions of the steam turbine power generation facility.

In order to solve the above-described problems, a steam turbine power generation facility according to the invention reheats a superheater that generates main steam, a first turbine driven by the main steam, and an exhaust of the first turbine. A reheater for generating reheat steam, a second turbine driven by the reheat steam, a third turbine driven by exhaust of the second turbine, and exhaust of the third turbine A condenser for condensing the condensate, a water supply system for supplying the condensate from the condenser to the superheater, a water supply pump for increasing the pressure of the water supply system, and an exhaust of the second turbine A pump-driven turbine that is driven by a part of or a bleed air and drives the feed water pump; a part of the exhaust or the bleed air of the second turbine that is provided at the inlet of the pump-driven turbine; and water that flows through the water supply system And Will exchange, the second with reducing the temperature of the portion or bleed of the exhaust turbine, the a desuperheater increasing the temperature of the water flowing through the water supply system, the said third extraction turbine pump and a backup system integrated supplied to drive the turbine, when the desuperheater is stopped, characterized by comprising a control unit that connects the said pump driving turbine backup system.

  In the steam turbine power generation facility according to the present invention, high performance can be achieved by increasing the steam conditions of the steam turbine power generation facility.

The systematic diagram which shows one Embodiment of the steam turbine power generation equipment which concerns on this invention. The schematic block diagram which shows especially a drain pot and its periphery. The systematic diagram which shows the modification of the steam turbine power generation equipment which concerns on this invention.

  An embodiment of a steam turbine power generation facility according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a system diagram showing an embodiment of a steam turbine power generation facility according to the present invention.

  In the present embodiment, the steam turbine power generation facility according to the present invention will be described by applying it to a steam turbine power generation facility employing, for example, a 700 ° C. supercritical pressure power generation system (A-USC: Advanced Ultra-Supercritical).

  The steam turbine power generation facility 1 has a steam turbine including an ultrahigh pressure turbine 11, a high pressure turbine 12, an intermediate pressure turbine 13, and low pressure turbines 14a and 14b. In the present embodiment, the ultrahigh pressure turbine 11 is a “first turbine”, the high pressure turbine 12 and the intermediate pressure turbine 13 are “second turbines” (respectively “first reheat turbine”, “second turbine”, respectively). The low pressure turbines 14a, 14b are "third turbines". The steam turbine power generation facility 1 includes a boiler 20 that superheats or reheats steam, a generator 21 that is connected to the steam turbine, and a condenser 22 that guides the exhaust of the steam turbine.

  The steam turbine power generation facility 1 has a water supply system 24 that supplies condensate from the condenser 22 to the feed water heaters 23a to 23d. The feed water system 24 includes a condensate pump 25, feed water heaters 23a and 23b, a deaerator 26, a feed water pump 27, feed water heaters 23c and 23d, and the like along the flow of the condensate. The steam turbine power generation facility 1 includes an overheat reducer 31 connected to an outlet pipe 30 that supplies a part of the exhaust gas from the intermediate pressure turbine 13, and a pump drive turbine 32 connected to the outlet of the overheat reducer 31. The superheat reducer 31 is connected to the turbine outlet on the rear stage side of the reheat turbine (the front stage side of the low-pressure turbine 14a).

  The steam turbine power generation facility 1 has a backup system 40 that functions when the overheat reducer 31 fails. The backup system 40 is a system that supplies the bleed air of the low-pressure turbine 14 a to the pump drive turbine 32. The valve 45 a opens and closes the outlet pipe 30 for supplying a part of the exhaust gas from the intermediate pressure turbine 13 to the overheat reducer 31. The valve 45b opens and closes a supply pipe 41 (backup system 40) for supplying the bleed air of the low-pressure turbine 14a to the pump drive turbine 32.

  The valves 45a and 45b are connected to the control unit 50, respectively. The control unit 50 transmits control signals Sa and Sb for controlling the opening and closing of the valves 45a and 45b.

  A drain pot 61 for detecting water leakage in the overheat reducer 31 is provided at the subsequent stage of the overheat reducer 31.

  FIG. 2 is a schematic configuration diagram specifically showing the drain pots 61a and 61b and the periphery thereof. The arrows in FIG. 2 indicate the flow of steam.

  The drain pot 61 a is provided in the outlet pipe 65 of the overheat reducer 31. The drain pot 61 b is provided in a drain reservoir 66 that extends horizontally from the outlet pipe 65. The drain pots 61a and 61b branch into a T shape with respect to the outlet pipe 65 and the drain reservoir 66, and the drain 62 accumulates at the lower end. The drain pots 61a and 61b have water level gauges 63a and 63b. The water level gauges 63a and 63b are connected to the control unit 50 (see FIG. 1), and transmit the measured water level data D to the control unit 50. The steam pipe 67 extends upward from the outlet pipe 65 and guides the steam discharged from the overheat reducer 31 to the pump drive turbine 32.

  Next, the operation of the steam turbine power generation facility 1 will be described.

  The superheater provided in the boiler 20 generates high-temperature steam (main steam) of 650 ° C. or higher using a heat source such as combustion heat. The main steam is supplied to the ultra-high pressure turbine 11 for work, and then reheated to high-temperature steam (first reheat steam) by the first reheater provided in the boiler 20.

  The reheated steam (first reheated steam) is supplied from the first reheater of the boiler 20 to the high pressure turbine 12. The reheat steam is heated to high-temperature steam (second reheat steam) again by the second reheater of the boiler 20 after working in the high-pressure turbine 12. The reheated steam (second reheated steam) is supplied to the intermediate pressure turbine 13. The second reheat steam is supplied to the low-pressure turbines 14 a and 14 b after working in the intermediate-pressure turbine 13.

  In this embodiment, a reheater is comprised by two, a 1st reheater and a 2nd reheater. The reheat turbine, which is the second turbine, includes two components, a high pressure turbine 12 and an intermediate pressure turbine 13. And as a whole, the exhaust from the ultra high pressure turbine 11, which is the first turbine to which the main steam is supplied, is reheated by the reheater of the boiler 20 to drive the reheat turbine and drive the reheat turbine. The later exhaust drives the low-pressure turbines 14a and 14b, which are the third turbine.

  The steam that has worked in the low-pressure turbines 14a and 14b is condensed in the condenser 22 to become condensate. Condensate is sequentially led to feed water heaters 23 a and 23 b and deaerator 26 by condensate pump 25. The feed water system 24 is pressurized by a feed water pump 27 and guided to the boiler 20 through feed water heaters 23c and 23d. The boiler 20 heats water and again generates main steam for power generation.

  The pump-driven turbine 32 is a separate turbine that is different from the ultra-high pressure, high pressure, medium pressure, and low pressure turbines 11 to 14 a and 14 b and drives the feed water pump 27.

  The working fluid of the pump drive turbine 32 is a part of the exhaust of the intermediate pressure turbine 13. Here, in the 700 ° C. class A-USC, the intermediate steam turbine 13 has an inlet steam temperature of 450 ± 30 ° C., an outlet steam temperature of about 350 ± 30 ° C., and a pressure of about 0.5 ± 0.2 MPa. Higher temperature than medium-pressure turbine. From the viewpoint of heat resistance of the pump drive turbine 32, it is difficult to use exhaust gas from the intermediate pressure turbine 13 as a working fluid of the pump drive turbine 32.

  On the other hand, the steam turbine power generation facility 1 in the present embodiment can be provided with the overheat reducer 31 at the inlet of the pump drive turbine 32 to reduce the exhaust temperature of the intermediate pressure turbine 13.

  Part of the exhaust gas from the intermediate pressure turbine 13 is guided to the outlet pipe 30. The outlet pipe 30 branches, a part of the steam is supplied to the deaerator 26, and the other steam is supplied to the superheat reducer 31. The valve 45a provided downstream of the branch of the outlet pipe 30 is opened during normal operation, and the valve 45b provided in the backup system 40 is closed.

  The overheat reducer 31 reduces and adjusts the temperature of the exhaust gas from the intermediate pressure turbine 13 by using a part of the water flowing through the boiler feed water pipe 28 that connects the feed water heater 23 d and the boiler 20. The amount of water supplied to the superheat reducer 31 is adjusted by the diameter of the pipe branched from the boiler water supply pipe 28 and the orifice. The water used for reducing the exhaust temperature is returned to the boiler feed pipe 28 again.

  The steam whose temperature has decreased in the superheat reducer 31 is supplied to the pump-driven turbine 32 to work. The pump drive turbine 32 is driven by steam and drives a feed water pump 27 provided at the rear stage of the deaerator 26. Further, the exhaust gas from the pump drive turbine 32 is guided to the condenser 22.

  Next, water leak detection using the drain pot 61 will be described.

  The steam turbine power generation facility 1 uses the steam that has passed through the superheat reducer 31 as the working fluid of the pump drive turbine 32. If a trouble such as water leakage occurs in the overheat reducer 31, the leaked water may flow into the pump drive turbine 32 and damage the pump drive turbine 32.

  In order to prevent this, as shown in FIG. 2, the steam turbine power generation facility 1 includes a drain pot 61 a, a drain pot 61 b, and water level meters 63 a and 63 b in the outlet pipe 65 and the drain reservoir 66 of the superheat reducer 31, respectively. Install.

  When water leakage occurs in the overheat reducer 31, water flows out to the outlet pipe 65 and the drain reservoir 66. The discharged water (drain 62) is accumulated in the drain pots 61a and 61b. Even during normal times, some drain 62 is collected in the drain pots 61a and 61b. When water leaks, the water levels in the drain pots 61a and 61b rise. When the water levels detected by the water level gauges 63a and 63b exceed a specified value, the control unit 50 can recognize that a trouble has occurred in the overheat reducer 31. As a result, damage to the pump drive turbine 32 can be prevented.

  Next, the action at the time of failure of the overheat reducer 31 of the steam turbine power generation facility 1 will be described.

  When a failure occurs in the overheat reducer 31 and the overheat reducer 31 needs to be stopped, the working fluid cannot be supplied to the pump drive turbine 32 and the feed water pump 27 cannot be driven. As a result, the condensate flowing through the water supply system 24 is not boosted and cannot be supplied to the boiler 20, which may stop the entire steam turbine power generation facility 1.

  The steam turbine power generation facility 1 in this embodiment includes a backup system 40 when the overheat reducer 31 fails. The backup system 40 supplies the bleed air from the low-pressure turbine 14 a to the pump drive turbine 32. At this time, the controller 50 switches to the backup system 40 by closing the valve 45a and opening the valve 45b, and supplies the bleed air from the low-pressure turbine 14a to the pump drive turbine 32.

  Usually, the extraction of a low-pressure turbine has a low pressure and a large volume. For this reason, when the extraction of the low-pressure turbine is used as the working fluid of the pump-driven turbine, it is necessary to increase the diameter of the extraction piping. However, when the bleed air of the low-pressure turbine 14a is used as a backup system for the overheat reducer 31, low-load operation (for example, about 50% of normal time) of the steam turbine power generation facility 1 is assumed. During low-load operation, by supplying a small amount of steam to the pump-driven turbine 32, a pipe having a large diameter can be eliminated.

  This steam turbine power generation facility 1 can eliminate the need for the pump-driven turbine 32 to have heat resistance by the overheat reducer 31 disposed in the front stage of the pump-driven turbine 32. Therefore, even if it is A-USC, the pump drive turbine 32 can use the material and structure similar to the conventional steam turbine power generation equipment (for example, 600 degreeC class steam turbine power generation equipment). As a result, it is possible to improve the performance of the steam turbine power generation facility by increasing the steam conditions while suppressing the cost of the entire steam turbine power generation facility.

  Further, when a water leak due to a trouble occurs in the overheat reducer 31, if it takes time to detect the water leak, water may flow into the pump-driven turbine. The steam turbine power generation facility 1 in the present embodiment can easily and quickly detect water leakage by double checking the drain pots 61a and 61b.

  Furthermore, the steam turbine power generation facility 1 also has a backup system 40 as a backup of the steam supplied to the pump drive turbine 32 when the overheat reducer 31 is out of order (when stopped). Thereby, the steam turbine power generation facility 1 is highly reliable, and can sufficiently exhibit the effect of improving the performance of the steam turbine power generation facility.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the steam turbine power generation facility 1 is not limited to a two-stage reheat turbine, but may be a one-stage reheat steam turbine power generation facility 100 shown in FIG.

  That is, in the steam turbine power generation facility 1 of FIG. 1, the boiler 20 includes two reheaters, a first reheater and a second reheater. On the other hand, in the steam turbine power generation facility 100 of FIG. 3, the boiler 120 includes only one reheater. The steam turbine includes a high-pressure turbine 111 (first turbine) that uses main steam from the superheater of the boiler 120 as a working fluid, and an intermediate-pressure turbine 112 (that uses reheat steam from the reheater of the boiler 120 as working fluid. (Second turbine) and low-pressure turbines 113a and 113b (third turbine) using the exhaust of the intermediate-pressure turbine 112 as a working fluid. In this case, the pump drive turbine 32 drives a part of the exhaust of the intermediate pressure turbine 112 whose temperature is reduced by the overheat reducer 31 as a working fluid. Other configurations of the steam turbine power generation facility 100 correspond to the steam turbine power generation facility 1 of FIG.

  Further, the pump drive turbine 32 may use the bleed air of the intermediate pressure turbines 13 and 112 as a working fluid.

  Furthermore, although the outlet pipe 65 and the drain reservoir 66 of the overheat reducer 31 have been described as extending horizontally, they may extend in the vertical direction (downward).

DESCRIPTION OF SYMBOLS 1,100 Steam turbine power generation equipment 11 Super high pressure turbine 12 High pressure turbine 13 Medium pressure turbine 14a, 14b Low pressure turbine 20, 120 Boiler 21 Generator 22 Condenser 24 Feed water system 27 Feed water pump 31 Overheat reducer 32 Pump drive turbine 40 Backup System 50 Controllers 61a, 61b Drain pots 63a, 63b Water level gauge 111 High-pressure turbine 112 Medium-pressure turbine 113a, 113b Low-pressure turbine

Claims (3)

A superheater that generates main steam;
A first turbine driven by the main steam;
A reheater that reheats the exhaust of the first turbine to generate reheat steam;
A second turbine driven by the reheat steam;
A third turbine driven by the exhaust of the second turbine;
A condenser for condensing and exhausting the exhaust of the third turbine;
A water supply system for supplying the condensate from the condenser to the superheater;
A water supply pump for increasing the pressure of the water supply system;
A pump-driven turbine that is driven by part of the exhaust of the second turbine or bleed and drives the feed pump;
A part of the exhaust of the second turbine or the bleed air provided at the inlet of the pump-driven turbine and the water flowing through the water supply system are heat-exchanged, and a part of the exhaust or the bleed of the second turbine An overheat reducer that reduces the temperature and increases the temperature of the water flowing through the water supply system ;
A backup system that supplies the third turbine bleed air to the pump drive turbine, and a control unit that connects the pump drive turbine and the backup system when the overheat reducer is stopped. Steam turbine power generation equipment. The second turbine has a first reheat turbine driven by a first reheat steam obtained by reheating the exhaust gas of the first turbine, and a second reheated exhaust gas of the first reheat turbine. steam turbine power plant according to claim 1, further comprising a second reheat turbine driven by reheat steam. A drain pot that is provided in an outlet pipe of the overheat reducer and accumulates drain generated in the outlet pipe;
Steam turbine power plant further according to claim 1, wherein with a water level detector for detecting the water level of the drain pot.

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