JP4818391B2 - Steam turbine plant and operation method thereof - Google Patents

Description

  The present invention relates to a steam turbine plant and an operating method thereof.

  Conventionally, in a steam turbine plant such as a large-capacity thermal power plant or nuclear power plant, a regeneration cycle method or a regeneration reheat cycle method is generally employed. In the regeneration cycle system, the water supply to the steam generator is heated using the low-pressure steam extracted from the intermediate stage of the steam turbine, thereby improving the thermal efficiency and increasing the maximum output that can be generated by one steam turbine. It is the purpose. Further, the regeneration reheat cycle method is a cycle in which the regeneration cycle method and the reheat cycle method are combined. The reheat cycle method introduces steam to a steam turbine and expands it to a predetermined pressure. This is extracted from the steam turbine and reheated in a reheater, and the purpose is to improve the thermal efficiency and not lower the dryness of the low-pressure steam at the end of expansion.

  FIG. 3 is a system diagram showing an example of a steam turbine plant that employs a conventional regenerative reheat cycle system that obtains electric power by driving a steam turbine with high-temperature and high-pressure steam generated in a boiler. In this figure, the high-temperature and high-pressure steam generated by the steam generator 111 flows into the high-pressure turbine 101 via the main steam pipe 312 and expands there to drive the high-pressure turbine 101. Most of the exhaust gas from the high-pressure turbine 101 is reheated to high-pressure and high-temperature steam by the reheater 111 a and then introduced into the intermediate-pressure turbine 102 via the high-temperature reheat steam pipe 305 to drive the intermediate-pressure turbine 102. . The exhaust from the intermediate pressure turbine 102 is supplied to the low pressure turbine 103 via the crossover pipe 301 to drive the low pressure turbine 103. In this way, each turbine is driven by steam, and the generator 104 directly connected to these turbines is driven to generate power. The exhaust from the low-pressure turbine 103 is sent to the condensate system, where the exhaust is sent to the condenser 105 and condensed by the cooling water, and then pumped by the condensate pump 106 and sent to the water supply system. In FIG. 3, the cooling water system is omitted. The feed water heating system is mainly composed of a low pressure feed water heater 107, a deaerator 108, a feed water pump 109, and a high pressure feed water heater 110. These facilities are sequentially arranged from the condenser 105 toward the steam generator 111, respectively. Connected in series. The low-pressure feed water heater 107, the deaerator 108, and the high-pressure feed water heater 110 respectively extract the turbine bleed extracted from the intermediate stages of the low-pressure turbine 103, the intermediate-pressure turbine 102, and the high-pressure turbine 101 through the bleed pipes 308, 307, and 302. It is a facility for receiving and heating boiler feed water. By heating the feed water in this way, the thermal efficiency of the entire plant is improved, and the feed water heated to a predetermined temperature in a plurality of stages is returned to the steam generator 111.

  In recent years, demands from other adjacent plants have diversified, and there is a request to effectively use a part of the steam generated in the steam turbine plant in these plants. In the steam turbine plant, in order to meet these demands, Steam is supplied to other plants. In other plants, process steam is used not only for heating purposes but also for heating, hot water supply, and the like. Usually, the steam drain used for these purposes is returned to the steam turbine plant. As described above, Patent Document 1 is known as a steam turbine plant that supplies steam to another plant.

JP 2007-85294 A

  However, when supplying process steam to another plant in an existing power plant, if the process steam supply amount increases, the steam supply amount to the steam turbine decreases, resulting in a decrease in steam pressure and a decrease in main steam flow rate. .

  Therefore, in the existing power plant, the steam generated by the steam generator is supplied to the outside of the system as process steam, and the balance between the supply quantity outside the system and the improvement of boiler efficiency and the increase of the main steam flow rate is controlled. There is a need for a steam turbine plant that can be operated and a method for operating the same.

  The present invention supplies the steam generated by the steam generator outside the system as a process steam at an existing power plant, and controls the balance between the supply amount outside the system, improvement in boiler efficiency, and increase in main steam flow rate. It is an object of the present invention to provide a steam turbine plant that can be operated and a method of operating the same.

  The present invention provides the following solutions.

  (1) While supplying a part of the steam as process steam through the process steam supply pipe, the remaining part is used for driving the steam turbine, and the extraction pipe from the steam turbine is connected to the feed water heater and the deaerator. In a steam turbine plant of a regenerative cycle system guided through, a bleed regulating valve capable of adjusting the flow rate of the bleed gas flowing through the bleed pipe, an outlet feed water thermometer for measuring the temperature of the feed water outlet of the feed water heater, and the outlet A steam turbine plant comprising: control means for controlling the extraction valve based on a temperature measured by a feed water thermometer.

  According to the configuration of (1), the steam turbine plant according to the present invention supplies a part of the steam as process steam through the process steam supply pipe, and the remaining part is used for driving the steam turbine. A regeneration cycle that guides the bleed air from the feed water heater and deaerator through the bleed pipe, and measures the temperature of the bleed regulating valve that can adjust the flow rate of the bleed gas flowing through the bleed pipe and the feed water outlet temperature of the feed water heater And an outlet feed water thermometer. Then, based on the temperature measured by the outlet feed water thermometer, the extraction regulating valve is controlled.

  That is, the steam turbine plant according to the present invention sets the outlet temperature of the feed water heater to a predetermined temperature by controlling the extraction regulating valve. Therefore, since the feed water temperature to the steam generator can be raised, the steam turbine plant according to the present invention supplies the steam generated by the steam generator outside the system as process steam in the existing power plant, and It is possible to control the balance between the supply amount to the boiler and the improvement of the boiler efficiency and the increase of the main steam flow rate.

  (2) a process steam control valve capable of adjusting a flow rate of the process steam flowing through the process steam supply pipe, and a turbine steam pressure gauge for measuring the pressure of the steam flowing into the steam turbine; The steam turbine plant according to (1), wherein the process steam control valve is further controlled based on a pressure measured by the turbine steam pressure gauge.

  According to the configuration of (2), the steam turbine plant described in (1) measures a process steam control valve capable of adjusting the flow rate of the process steam flowing through the process steam supply pipe and the pressure of the steam flowing into the steam turbine. A turbine steam pressure gauge. The control means further controls the process steam regulating valve based on the pressure measured by the turbine steam pressure gauge.

  That is, the steam turbine plant according to the present invention sets the outlet temperature of the feed water heater to a predetermined temperature by controlling the extraction regulating valve, and further uses it for driving the steam turbine by controlling the process steam regulating valve. The balance between the steam flow rate and the process steam supply amount is controlled. Therefore, since the steam flow rate and the supply amount of process steam are controlled, the steam turbine plant according to the present invention supplies the steam generated by the steam generator outside the system as process steam in the existing power plant. It is possible to control the balance between the supply amount to the outside, the improvement in boiler efficiency and the increase in the main steam flow rate.

  (3) While supplying a part of the steam as process steam through the process steam supply pipe, the remaining part is used for driving the steam turbine, and the extraction pipe from the steam turbine is connected to the feed water heater and the deaerator. A regenerative cycle steam turbine plant led through a bleeder regulating valve capable of adjusting a flow rate of the bleed gas flowing through the bleed pipe, and an outlet feed water thermometer for measuring the temperature of the feed water outlet of the feed water heater. An operation method for the steam turbine plant, comprising the step of controlling the extraction regulating valve based on a temperature measured by the outlet feed water thermometer.

  That is, the operating method of the steam turbine plant according to the present invention sets the outlet temperature of the feed water heater to a predetermined temperature by controlling the extraction regulating valve. Therefore, since the feed water temperature to the boiler can be raised, the operation method of the steam turbine plant according to the present invention supplies the steam generated by the steam generator outside the system as process steam in the existing power plant. It is possible to control the balance between the supply amount to the outside, the improvement in boiler efficiency and the increase in the main steam flow rate.

  According to the present invention, in an existing power plant, the steam generated by the steam generator is supplied outside the system as process steam, and the balance between the supply amount outside the system, improvement in boiler efficiency, and increase in the main steam flow rate is achieved. It is possible to provide a steam turbine plant that can control the operation and a method for operating the same.

It is a distribution diagram showing an example of an embodiment of steam turbine plant 10 of the present invention. FIG. 2 is a diagram illustrating an example when the outlet feed water temperature of the high-pressure feed water heater 110 is controlled. 1 is a system diagram showing an example of a steam turbine plant that employs a conventional regenerative reheat cycle system that obtains electric power by driving a steam turbine with high-temperature and high-pressure steam generated in a boiler.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a system diagram showing an example of an embodiment of a steam turbine plant 10 of the present invention. The steam turbine plant 10 of the present invention mainly includes a steam generator 111 (including a reheater 111a), a high pressure turbine 101, an intermediate pressure turbine 102, a low pressure turbine 103, a generator 104, a condenser 105, and a condensate pump 106. The low-pressure feed water heater 107, the deaerator 108, the feed water pump 109, the high-pressure feed water heater 110, and the like constitute a regenerative reheat cycle. The steam turbine plant 10 includes an extraction regulating valve 201, an outlet feed water thermometer 202, a process steam regulating valve 203, a turbine steam pressure gauge 207, and a controller 121, and an outlet of feed water of the high pressure feed water heater 110. The temperature is set to a predetermined temperature, and the balance between the flow rate of steam used for driving the steam turbine and the supply amount of process steam is controlled.

  In addition to these facilities, a cooling water facility for cooling the cooling water supplied to the condensate facility, a feed water condensate treatment facility, and other incidental facilities may be provided. In FIG. 1, the steam turbine is installed by combining a high-pressure turbine 101, an intermediate-pressure turbine 102, and a low-pressure turbine 103. However, the steam turbine is not limited thereto, and an ultrahigh-pressure turbine and an ultrahigh-pressure turbine are considered in consideration of power generation capability of the steam turbine plant 10. -A high pressure turbine, a high / medium pressure turbine, a medium / low pressure turbine, or the like may be combined.

  Examples of the steam generator 111 include boilers and reactor steam generators. The high-temperature and high-pressure steam generated in the steam generator 111 flows into the high-pressure turbine 101, where it adiabatically expands and drives the high-pressure turbine 101. A part of the steam is extracted from the intermediate stage of the high-pressure turbine 101 and supplied to the high-pressure feed water heater 110 through the extraction pipe 302.

  Exhaust gas from the high-pressure turbine 101 flows through the low-temperature reheat steam pipe 303 and is reheated to high-pressure and high-temperature steam by the reheater 111a. In FIG. 1, a one-stage reheat method is shown as a reheat method, but a two-stage reheat method may be used. The steam temperature of this reheated steam is usually substantially equal to the main steam temperature generated by the steam generator 111.

  The reheat steam reheated by the reheater 111a flows out of the high temperature reheat steam pipe 305 from here. The high-temperature reheat steam pipe 305 is branched into a process steam supply pipe 304 and a pipe 306 toward the intermediate pressure turbine 102, and a part of the reheat steam is supplied as process steam to another plant, The remainder flows into the intermediate pressure turbine 102.

  The steam that has flowed into the intermediate pressure turbine 102 from the branch point via the pressure regulating valve 205 expands and drives the intermediate pressure turbine 102, and a part thereof is extracted as steam from the intermediate stage of the intermediate pressure turbine 102. , And sent to the deaerator 108 through the extraction pipe 307. The remaining steam is exhausted to the low-pressure turbine 103 via the crossover pipe 301.

  One end of the crossover pipe 301 is connected to an intermediate position of the low-pressure turbine 103, and steam flowing into the low-pressure turbine 103 through the crossover pipe 301 further passes through the inside toward both sides in the axial direction of the low-pressure turbine. The low-pressure turbine 103 is driven by expanding until the pressure becomes low. Extraction points are provided in the intermediate stage of the low-pressure turbine 103, and steam extracted from these extraction points flows into the low-pressure feed water heater 107 through the extraction pipe 308. Further, the exhaust from the low-pressure turbine 103 is sent to the condenser 105.

  When the high-pressure turbine 101, the intermediate-pressure turbine 102, and the low-pressure turbine 103 are driven, the generator 104 is driven to generate power.

  In the condenser 105, the steam exhausted from the low-pressure turbine 103 is recovered as drainage. Furthermore, the condenser 105 can be newly replenished with water-treated industrial water. A condensate pump 106 is provided on the downstream side of the condenser 105, and the condensed drain is pumped by this and sent to the feed water heating system via the condensate pipe 309. The condensate pipe 309 can be provided with a hydrogen cooler, an air extractor, a ground condenser, etc. (not shown) in the middle thereof.

  The feed water heating system includes a low pressure feed water heater 107, a deaerator 108, a feed water pump 109, and a high pressure feed water heater 110, and feed water to the steam generator 111 is heated in this system. The low-pressure feed water heater 107 may be composed of a plurality of stages in series, for example, a first feed water heater, a second feed water heater, a third feed water heater, and the like. Similarly, the high-pressure feed water heater 110 may be composed of a plurality of stages in series, for example, a fifth feed water heater, a sixth feed water heater, a seventh feed water heater, and the like. By heating the feed water to a predetermined temperature in a plurality of stages, the thermal efficiency of the entire plant can be improved.

  The feed water heated in the deaerator 108 is sent to the high-pressure feed water heater 110 through the feed pipe 310 by the feed water pump 109.

  This feed water is heated by the steam extracted from the intermediate stage of the high-pressure turbine 101 by the extraction pipe 302.

  In the high-pressure feed water heater 110, for example, feed water heated from about 240 ° C. to about 260 ° C. is sent to the steam generator 111 via the feed water pipe 311 and further heated to generate steam.

  The controller 121 acquires the outlet feed water temperature as a measurement result from the outlet feed water thermometer 202 provided on the feed water outlet side of the high-pressure feed water heater 110. Then, the controller 121 controls the extraction water supply valve 201 provided in the middle of the extraction pipe 302 to control the outlet water supply temperature to the set temperature. For example, when the measured outlet feed water temperature is lower than the set temperature, the controller 121 controls the bleed adjustment valve 201 to open, and when the measured outlet feed water temperature is higher than the set temperature. Controls the extraction valve 201 in the closing direction. The opening / closing of the bleed adjustment valve 201 is controlled within a predetermined limit.

  Further, the controller 121 branches the high-temperature reheat steam pipe 305 from the process steam supply pipe 304, and the reheat steam pressure as a measurement result from the turbine steam pressure gauge 207 provided in the pipe 306 toward the intermediate pressure turbine 102. To get. The controller 121 controls the reheat steam pressure to be a predetermined steam pressure by controlling the process steam control valve 203 provided in the middle of the process steam supply pipe 304 based on the reheat steam pressure. . For example, when the measured reheat steam pressure is lower than a predetermined steam pressure, the controller 121 controls the valve opening degree of the process steam control valve 203 to be closed. When the measured reheat steam pressure is higher than the predetermined steam pressure and does not satisfy the predetermined process steam supply amount, the process steam control valve 203 is configured to satisfy the predetermined process steam supply amount. The valve opening degree is controlled in the opening direction, and when the predetermined process steam supply amount is satisfied, the valve opening degree of the process steam adjusting valve 203 is maintained. The valve opening degree of the process steam control valve 203 is controlled within a predetermined limit. As a result, the balance between the main steam flow used for driving the steam turbine and the supply amount of process steam can be controlled.

  For example, when the process steam is not supplied, the main steam flow rate is 470 t / h and the output is 156 MW. When the process steam is supplied, for example, the feed water inlet temperature to the low pressure feed water heater 107 is 38.6 ° C., the exit temperature is 118.0 ° C., the feed water inlet temperature to the high pressure feed water heater 110 is 130.0 ° C., The outlet temperature is 242.7 ° C., the main steam flow rate is 457 t / h, the extraction amount from the high-pressure turbine 101 to the high-pressure feed water heater 110 is 28.3 t / h, and the reheat steam flow rate is 374 t / h. Is 182.7 t / h, the reheat turbine entrainment amount which is the amount of steam flowing into the intermediate pressure turbine 102 is 140 t / h, and the output of the generator 104 is 98.7 MW. In this case, the controller 121 controls the extraction regulating valve 201, whereby the extraction amount from the high-pressure turbine 101 to the high-pressure feed water heater 110 is 45.4 t / h, and the outlet temperature of the high-pressure feed water heater 110 is 259.3. The main steam flow rate is 474 t / h, the reheat steam flow rate is 374 t / h, the process steam supply rate is 182.5 t / h, and the reheat turbine entrainment rate is 140 t / h. As a result, the output of the generator 104 is 99.7 MW. Furthermore, the controller 121 controls the process steam control valve 203 to ensure the reheat turbine feed amount, and to balance the steam flow rate used for driving the steam turbine and the process steam supply amount. Can keep.

  FIG. 2 is a diagram illustrating an example when the outlet feed water temperature of the high-pressure feed water heater 110 is controlled. In FIG. 2, the vertical axis represents the main steam flow rate (t / h) and output (MW) per hour, and the horizontal axis represents the outlet feed water temperature (° C.) of the high-pressure feed water heater 110. The outlet feed water temperature of the high-pressure feed water heater 110 rises as the valve opening degree of the bleed adjustment valve 201 provided in the bleed pipe 302 increases, and falls as the valve opening degree decreases.

  As shown in FIG. 2, when the outlet water supply temperature rises from around 240 ° C. to around 260 ° C., the main steam flow rate increases from around 455 t / h to around 475 t / h, and the output increases from around 98.7 MW to 99.99. It shows that it has increased to around 7 MW. In this case, the reheat turbine entrapment amount is 140 t / h, and the process steam supply amount is secured around 182.5 t / h on average.

  According to the present embodiment, the steam turbine plant 10 according to the present invention supplies a part of the steam as process steam through the process steam supply pipe 304 and uses the remaining part for driving the steam turbines 101, 102, and 103. Then, a regeneration cycle for guiding the bleed air from the steam turbines 101, 102, 103 to the high-pressure feed water heater 110, the deaerator 108, and the low-pressure feed water heater 107 through the bleed pipes 302, 307, 308 is performed. A bleed adjustment valve 201 capable of adjusting the flow rate of the bleed air flowing through 302, an outlet feed water thermometer 202 that measures the temperature of the feed water outlet of the feed water heater, and a controller 121 are provided. Then, the controller 121 controls the extraction regulating valve 201 based on the temperature measured by the outlet feed water thermometer 202.

  Furthermore, a process steam control valve 203 capable of adjusting the flow rate of the process steam flowing through the process steam supply pipe 304 and a turbine steam pressure gauge 207 for measuring the pressure of the steam flowing into the steam turbine 102 are provided. Then, the controller 121 further controls the process steam control valve 203 based on the pressure measured by the turbine steam pressure gauge 207. Therefore, the feed water temperature to the steam generator 111 can be raised, and the steam flow rate and the amount of process steam supplied can be controlled. Therefore, the steam turbine plant 10 according to the present invention can While supplying the steam generated by the generator 111 as process steam to the outside of the system, it is possible to control the balance between the supply amount to the outside of the system and the improvement in boiler efficiency and the increase in the main steam flow rate.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 10 Steam turbine plant 101 High pressure turbine 102 Medium pressure turbine 103 Low pressure turbine 104 Generator 105 Condenser 107 Low pressure feed water heater 110 High pressure feed water heater 111 Steam generator 121 Controller

Claims (2)

A part of the steam is supplied as process steam through the process steam supply pipe, and the remaining part is used for driving the steam turbine, and the extracted air from the steam turbine is guided to the feed water heater and the deaerator through the extraction pipe. In a regenerative cycle steam turbine plant,
A bleed adjustment valve capable of adjusting a flow rate of the bleed air flowing through the bleed pipe;
An outlet feed water thermometer for measuring the temperature of the feed water outlet of the feed water heater;
A process steam control valve capable of adjusting the flow rate of the process steam flowing through the process steam supply pipe;
A turbine steam pressure gauge for measuring the pressure of steam flowing into the steam turbine;
Control means for controlling the extraction regulating valve based on the temperature measured by the outlet feed water thermometer , and further controlling the process steam regulating valve based on the pressure measured by the turbine steam pressure gauge ;
A steam turbine plant comprising: A part of the steam is supplied as process steam through the process steam supply pipe, and the remaining part is used for driving the steam turbine, and the extracted air from the steam turbine is guided to the feed water heater and the deaerator through the extraction pipe. a method of operating a steam turbine plant regeneration cycle type,
The steam turbine plant is
A bleed adjustment valve capable of adjusting a flow rate of the bleed air flowing through the bleed pipe;
An outlet feed water thermometer for measuring the temperature of the feed water outlet of the feed water heater;
A process steam control valve capable of adjusting the flow rate of the process steam flowing through the process steam supply pipe;
A turbine steam pressure gauge for measuring the pressure of steam flowing into the steam turbine,
The driving method is as follows:
On the basis of the temperature measured by the outlet water temperature gauge, and controlling the bleed control valve,
Controlling the process steam regulating valve based on the pressure measured by the turbine steam pressure gauge;
A driving method characterized by comprising:

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