JP5523810B2 - Combined cycle power generation facility and its feed water heating method - Google Patents

Description

  The present invention includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine. Electric power is generated by the gas turbine, exhaust gas from the gas turbine is guided to an exhaust heat recovery boiler, and feed water is heated to form steam. The present invention relates to a combined cycle power generation facility for generating power by guiding it to a gas turbine and a method for heating the feed water.

  In a general combined cycle power generation facility, when exhaust gas from a gas turbine passes outside the piping of a low-pressure economizer at the bottom of the exhaust heat recovery boiler, water contained in the exhaust gas flows through the piping. Condensation may occur due to the temperature difference between the pipe and the pipe. In particular, when a fuel containing sulfur is used, sulfuric acid is generated on the outer surface of the pipe of the low-pressure economizer, and corrosion of this pipe becomes serious.

  In order to prevent this, in the conventional combined cycle power generation facility, a part of the low-pressure steam flowing into the steam turbine for the purpose of setting the feed water temperature flowing in the pipe of the low-pressure economizer higher than the dew point of the exhaust gas, Or the function (for example, refer to patent documents 1 or 2) which uses a part of extraction from a steam turbine as steam for heating feed water, or the function to recirculate feed water from the low-pressure economizer of a waste heat recovery boiler (for example, And Patent Document 3).

JP-A-55-109708 JP 59-101512 A Japanese Patent Laid-Open No. 11-2000889

  In a general combined cycle power generation facility, when exhaust gas is discharged from a chimney into the atmosphere, particularly in a state where the atmospheric temperature is low, moisture contained in the exhaust gas may be condensed to generate white smoke. In particular, as described in Patent Documents 1 to 3, when the combined cycle power generation facility has a function of heating the feed water, since the exhaust gas temperature does not decrease, white smoke is likely to be generated. The issue was how to control the occurrence.

  The object of the present invention has been made in consideration of the above circumstances, and is capable of preventing corrosion of piping in the exhaust heat recovery boiler, and combined cycle power generation capable of suppressing the generation of white smoke from the chimney of the exhaust heat recovery boiler. The object is to provide a facility and its feed water heating method.

A combined cycle power generation facility according to the present invention includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine, and guides exhaust gas from the gas turbine to the exhaust heat recovery boiler to heat feed water to form steam, which is used as the steam. In a combined cycle power generation facility that conducts power generation by guiding to a steam turbine, a feed water system that includes a feed water heater that guides extraction from the steam turbine and heats the feed water, and supplies the heated feed water to the exhaust heat recovery boiler And a feed water heater bypass line that is connected to the feed water system and bypasses the feed water heater, and provided in the feed water heater bypass line, and by adjusting a bypass flow rate that flows through the feed water heater bypass line, a flow control valve for controlling the feed water temperature at the outlet of the feed water heater, downstream of the feed water heater in the water supply system, A feed water thermometer that is provided downstream of the connection point of the feed water heater bypass line and measures the feed water temperature, an atmospheric thermometer that measures the atmospheric temperature, an atmospheric hygrometer that measures the atmospheric humidity, and the exhaust heat An exhaust gas dew point meter for measuring the dew point of the exhaust gas discharged from the recovery boiler; and a target value of the feed water temperature is calculated from the atmospheric dew point obtained from the atmospheric temperature and the atmospheric humidity and the dew point of the exhaust gas, and the feed water thermometer And a control device that adjusts the opening degree of the flow rate control valve so as to control the feed water temperature measured in step 1 to the target value of the feed water temperature .

  In addition, the feed water heating method for the combined cycle power generation facility according to the present invention includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine. The exhaust gas from the gas turbine is guided to the exhaust heat recovery boiler to heat the feed water to generate steam. In the feed water heating method of the combined cycle power generation facility that conducts power generation by introducing the steam to the steam turbine, the feed water heater that guides the bleed air from the steam turbine and heats the feed water is provided. A water supply system that supplies the exhaust heat recovery boiler, and is connected to the water supply system to adjust a bypass flow rate that flows through a water supply heater bypass line that bypasses the water supply heater; The feed water temperature is controlled to a target value of the feed water temperature obtained from the dew point of the atmosphere and the dew point of the exhaust gas.

  Furthermore, the combined cycle power generation facility according to the present invention includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine. The exhaust gas from the gas turbine is guided to the exhaust heat recovery boiler to heat the feed water to form steam. In a combined cycle power generation facility for generating power by introducing the steam to the steam turbine, a part of the water supply heated by the exhaust heat recovery boiler is recirculated by being connected to a water supply system for supplying water to the exhaust heat recovery boiler The feed water recirculation line and the feed water recirculation line provided to control the feed water temperature supplied from the feed water system to the exhaust heat recovery boiler by adjusting the feed water recirculation flow rate flowing through the feed water recirculation line A flow rate control valve, a feed water thermometer for measuring a feed water temperature provided downstream of a connection point of the feed water recirculation line in the feed water system, and an atmospheric temperature An atmospheric thermometer to measure, an atmospheric hygrometer to measure atmospheric humidity, an exhaust gas dew point meter to measure the dew point of exhaust gas discharged from the exhaust heat recovery boiler, and an atmospheric dew point determined from the atmospheric temperature and atmospheric humidity And a control device for calculating the target value of the feed water temperature from the dew point of the exhaust gas and adjusting the opening of the flow rate control valve to control the feed water temperature measured by the feed water thermometer to the target value of the feed water temperature It is characterized by having.

  In addition, the feed water heating method for the combined cycle power generation facility according to the present invention includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine. The exhaust gas from the gas turbine is guided to the exhaust heat recovery boiler to heat the feed water to generate steam. In the feed water heating method of the combined cycle power generation facility that conducts power generation by introducing the steam to the steam turbine, the steam is connected to a water supply system that supplies water to the exhaust heat recovery boiler and is heated by the exhaust heat recovery boiler. A feed water recirculation line for recirculating a part of the feed water, and adjusting a feed water recirculation flow rate flowing through the feed water recirculation line to control a feed water temperature supplied from the feed water system to the exhaust heat recovery boiler. Control is made to a target value of the feed water temperature obtained from the dew point of the atmosphere and the dew point of the exhaust gas.

  According to the combined cycle power generation facility and the feed water heating method according to the present invention, the feed water heated by the feed water heater is supplied to the exhaust heat recovery boiler. The temperature difference between the pipes can be reduced, the occurrence of condensation on the outer surface of the pipe can be prevented, and corrosion of the pipe can be prevented. Moreover, since the feed water temperature at the outlet of the feed water heater is controlled by adjusting the flow rate of the feed water flowing through the feed water heater bypass line, the temperature reduction of the exhaust gas discharged from the waste heat recovery boiler is promoted, and the exhaust heat recovery The generation of white smoke from the boiler chimney can be suppressed.

  Furthermore, according to the combined cycle power generation facility and its feed water heating method according to the present invention, the heated feed water from the feed water recirculation line is supplied to the waste heat recovery boiler, so The temperature difference between the flowing water supply and the exhaust gas can be reduced, the occurrence of condensation on the outer surface of the pipe can be prevented, and the corrosion of the pipe can be prevented. In addition, since the feed water temperature supplied to the exhaust heat recovery boiler is controlled by adjusting the feed water recirculation flow rate through the feed water recirculation line, the temperature reduction of the exhaust gas discharged from the exhaust heat recovery boiler is promoted, Generation of white smoke from the chimney of the heat recovery boiler can be suppressed.

The systematic diagram which shows 1st Embodiment in the combined cycle power generation equipment which concerns on this invention. The systematic diagram which shows 2nd Embodiment in the combined cycle power generation equipment which concerns on this invention.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[A] First embodiment (FIG. 1)
A combined cycle power generation facility 10 illustrated in FIG. 1 includes a gas turbine 11, an exhaust heat recovery boiler 12, a steam turbine 13, and a feed water heating system 14. As will be described in detail later, the combined cycle power generation facility 10 generates power with a gas turbine 11, and exhaust gas from the gas turbine 11 is led to an exhaust heat recovery boiler 12 to heat feed water into steam, which is used as a steam turbine. 13 to generate electricity.

  The feed water heating system 14 includes a feed water system 16 provided with a feed water heater 15, a feed water heater bypass line 17 that bypasses the feed water heater 15, a flow rate adjusting valve 18 provided in the feed water heater bypass line 17, and a feed water temperature. It comprises a total meter 19, an atmospheric thermometer 20a, an atmospheric hygrometer 20b, an exhaust gas dew point meter 21 and a control device 22.

  The gas turbine 11 includes an intake chamber 23, a compressor 24, a combustor 25, and a turbine 26, and drives a generator 27. In the gas turbine 11, the fuel gas supplied to the combustor 25 is mixed with the air compressed by the compressor 24 through the intake chamber 23 and combusted in the combustor 25, and becomes a high-temperature high-pressure gas. The turbine 26 is expanded to work, and the generator 27 is driven.

  The exhaust heat recovery boiler 12 includes a high pressure superheater 28, a reheater 29, a high pressure evaporator 30, a high pressure drum 30a, an intermediate pressure superheater 31, a low pressure superheater 32 from the upstream side of the flow of exhaust gas from the gas turbine 11. It has an intermediate pressure evaporator 33, an intermediate pressure drum 33a, a high pressure economizer 34, an intermediate pressure economizer 35, a low pressure evaporator 36, a low pressure drum 36a, a low pressure economizer 37, an exhaust gas flue 38 and a chimney 39. Composed. The steam turbine 13 includes a high pressure turbine 40, an intermediate pressure turbine 41, and a low pressure turbine 42, and drives the generator 43.

  Between the exhaust heat recovery boiler 12 and the steam turbine 13, the high-pressure main steam pipe 44 connects the outlet of the high-pressure superheater 28 and the inlet of the high-pressure turbine 40, and the low-pressure main steam pipe 45 connects the low-pressure superheater 32. The outlet and the inlet of the low-pressure turbine 42 are connected, the low-temperature reheat steam pipe 46 connects the outlet of the high-pressure turbine 40 and the inlet of the reheater 29, and the high-temperature reheat steam pipe 47 connects to the outlet of the reheater 29. The inlet of the intermediate pressure turbine 41 is connected. Further, the intermediate pressure superheater 31 and the low-temperature reheat steam pipe 46 are connected by an intermediate pressure main steam pipe 48.

  The high-temperature exhaust gas discharged from the gas turbine 11 is exchanged with the feed water in the exhaust heat recovery boiler 12 through the exhaust gas duct 49 and then discharged from the chimney 39 to the atmosphere through the exhaust gas flue 38.

  That is, in the exhaust heat recovery boiler 12, the feed water supplied from the main feed pipe 50 of the feed water system 16 is sequentially heated by the low pressure economizer 37 and the low pressure evaporator 36, and a part of the low pressure superheater 32 is fed by the low pressure drum 36a. And is heated to generate low-pressure steam, which is introduced into the low-pressure turbine 42 along with the steam discharged from the intermediate-pressure turbine 41 through the low-pressure main steam pipe 45.

  Further, a part of the feed water heated by the low-pressure evaporator 36 of the exhaust heat recovery boiler 12 passes through the feed water pump 51, and a part thereof is further heated sequentially by the medium pressure economizer 35 and the intermediate pressure evaporator 33. . The steam heated by the intermediate pressure evaporator 33 is further heated by the intermediate pressure superheater 31 through the intermediate pressure drum 33a to generate intermediate pressure steam, and the low temperature reheat steam pipe 46 through the intermediate pressure main steam pipe 48. And is introduced into the reheater 29. The remaining feed water heated by the low-pressure evaporator 36 is sequentially heated by the high-pressure economizer 34 and the high-pressure evaporator 30 via the feed water pump 51, and further heated by the high-pressure superheater 28 via the high-pressure drum 30a to become high-pressure steam. Then, it is introduced into the high-pressure turbine 40 through the high-pressure main steam pipe 44.

  In the steam turbine 13, the steam discharged from the high-pressure turbine 40 is introduced into the reheater 29 by the low-temperature reheat steam pipe 46 together with the intermediate pressure steam from the intermediate pressure main steam pipe 48 and heated. The steam heated by the reheater 29 is introduced into the intermediate pressure turbine 41 through the high temperature reheat steam pipe 47. The steam discharged from the intermediate pressure turbine 41 flows into the low pressure main steam pipe 45 and is introduced into the low pressure turbine 42 together with the low pressure steam from the low pressure superheater 32. The steam discharged from the low-pressure turbine 42 is cooled by the condenser 52 to become condensed water, and is sequentially discharged from the main water supply pipe 50 by the condensate pump 53 via the ground steam condenser 54 and the feed water heater 15. It is introduced into the low pressure economizer 37 of the exhaust heat recovery boiler 12.

  The feed water system 16 of the feed water heating system 14 includes a main feed pipe 50 in which a condenser 52, a condensate pump 53, a ground steam condenser 54, and a feed water heater 15 are sequentially arranged from the upstream side. The feed water heated by the feed water heater 15 is supplied to the low pressure economizer 37 of the exhaust heat recovery boiler 12. The feed water heater 15 introduces steam (extracted air) extracted from the middle of the paragraph of the low-pressure turbine 42 using an extract pipe 55, and heats the feed water by exchanging heat with the supplied water.

  The feed water heater bypass line 17 that bypasses the feed water heater 15 is connected to the main feed pipe 50 of the feed water system 16, and the flow rate adjusting valve 18 is disposed in the feed water heater bypass line 17. The flow rate adjusting valve 18 controls the feed water temperature from the outlet of the feed water heater 15 by adjusting the bypass flow rate flowing through the feed water heater bypass line 17. The opening degree of the flow rate control valve 18 is controlled by the control device 22 based on measurement data from the feed water thermometer 19, the atmospheric thermometer 20a, the atmospheric hygrometer 20b, and the exhaust gas dew point meter 21.

  In other words, the feed water thermometer 19 is installed downstream of the feed water heater 15 in the main feed pipe 50 of the feed water system 16 and downstream of the connection point A to the main feed pipe 50 of the feed water heater bypass line 17. The temperature of the feed water after the bypass flow from the feed water heater bypass line 17 joins is measured. The atmospheric thermometer 20a and the atmospheric hygrometer 20b are installed in the vicinity of the chimney 39 of the exhaust heat recovery boiler 12, and measure the atmospheric temperature and atmospheric humidity, respectively.

  The exhaust gas dew point meter 21 is installed in the exhaust gas flue 38 or the chimney 39 of the exhaust heat recovery boiler 12 and measures the dew point of the exhaust gas discharged from the exhaust heat recovery boiler 12. The exhaust gas dew point meter 21 actually calculates and determines the dew point of the exhaust gas based on the temperature and humidity of the exhaust gas. Here, the dew point of the exhaust gas is a temperature at which water vapor in the exhaust gas condenses.

  The control device 22 calculates the atmospheric dew point from the atmospheric temperature and atmospheric humidity measured by the atmospheric thermometer 20a and the atmospheric hygrometer 20b, respectively. This atmospheric dew point is the temperature at which water vapor in the atmosphere condenses. And the control apparatus 22 calculates the target value of feed water temperature from the dew point of the exhaust gas measured with the exhaust gas dew point meter 21, and the calculated dew point of the said atmosphere. When the dew point of the atmosphere is higher than the dew point of the exhaust gas, the control device 22 determines the lower limit value of the feed water temperature from the dew point of the exhaust gas, determines the upper limit value of the feed water temperature from the dew point of the atmosphere, and lower limit values of these feed water temperatures. The target value of the feed water temperature is set within the range between the upper limit value and the upper limit value.

  The reason why the lower limit value of the feed water temperature is set from the dew point of the exhaust gas is that if the temperature of the feed water flowing in the pipe in the low pressure economizer 37 of the exhaust heat recovery boiler 12 is lower than the dew point of the exhaust gas flowing outside the pipe, the exhaust gas This is because the water vapor inside condenses and condensation occurs on the outer surface of the pipe.

  The reason for setting the upper limit value of the water supply temperature from the dew point of the atmosphere is as follows. That is, when the temperature of the feed water flowing in the pipe in the low pressure economizer 37 of the exhaust heat recovery boiler 12 rises, the heat exchange with the exhaust gas flowing outside the pipe decreases, the exhaust gas temperature does not decrease, and the temperature becomes high. Maintained. When this high-temperature exhaust gas is released from the chimney 39 of the exhaust heat recovery boiler 12 into the atmosphere, white smoke is likely to be generated. Therefore, it is necessary to suppress the generation of white smoke by setting the feed water temperature below the dew point of the atmosphere. is there.

  When the atmospheric temperature decreases and the atmospheric dew point is lower than or equal to the exhaust gas dew point, the control device 22 sets the target value of the feed water temperature based on the exhaust gas dew point, that is, the exhaust gas dew point. On the other hand, it is set taking into account a predetermined margin temperature. In this case, the prevention of condensation on the outer surface of the pipe in the low pressure economizer 37 has priority over the generation of white smoke.

  The control device 22 sets the target value of the feed water temperature as described above, and the feed water temperature after the bypass flow merging from the feed water heater bypass line 17 measured by the feed water thermometer 19 is the target of the feed water temperature. In order to control the value, the opening of the flow rate adjusting valve 18 of the feed water heater bypass line 17 is adjusted to control the feed water temperature at the outlet of the feed water heater 15. Note that the target value of the feed water temperature may be a constant value or a value within a predetermined range.

  Since it was configured as described above, according to the present embodiment, the following effects (1) and (2) are achieved.

  (1) Since the feed water heated by the feed water heater 15 is supplied to the low pressure economizer 37 of the exhaust heat recovery boiler 12 through the main feed pipe 50, the feed water flows inside and outside the pipe in the low pressure economizer 37, respectively. The temperature difference between the exhaust gas and the exhaust gas can be reduced, the occurrence of condensation on the outer surface of the pipe can be prevented, and corrosion of the pipe can be prevented. In particular, even when the exhaust gas contains a sulfur content, the production of sulfuric acid due to the occurrence of condensation is suppressed, so that corrosion of the pipe can be reliably prevented.

  (2) The flow rate adjustment valve 18 of the feed water heater bypass line 17 adjusts the flow rate of the feed water (bypass flow) flowing through the feed water heater bypass line 17 so that the feed water temperature at the outlet of the feed water heater 15 The temperature is controlled to promote heat exchange. As a result, the temperature reduction of the exhaust gas flowing through the exhaust gas flue 38 and the chimney 39 of the exhaust heat recovery boiler 12 is promoted, and the generation of white smoke from the chimney 39 can be suppressed.

[B] Second embodiment (FIG. 2)
FIG. 2 is a system diagram showing a second embodiment of the combined cycle power generation facility according to the present invention. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The difference between the combined cycle power generation facility 60 of the present embodiment and the combined cycle power generation facility 10 of the above embodiment is the configuration of the feed water heating system 61, and the feed water heater bypass line 17 of the feed water heating system 14 of the above embodiment. Instead of this, a water supply recirculation line 62 is provided, a flow rate adjusting valve 63 is provided in the water supply recirculation line 62, and the water heater 15 is further omitted.

  That is, the feed water recirculation line 62 is connected to the main feed pipe 50 of the feed water system 16 and is heated by the low pressure economizer 37, the low pressure evaporator 36, and the medium pressure economizer 35 of the exhaust heat recovery boiler 12. Is recirculated from the medium pressure economizer 35 to the water supply system 16. Further, the flow rate adjusting valve 63 adjusts the feed water recirculation flow rate flowing through the feed water recirculation line 62, thereby supplying water supplied from the main water supply pipe 50 of the water supply system 16 to the low pressure economizer 37 of the exhaust heat recovery boiler 12. To control the temperature.

  The opening degree of the flow rate adjusting valve 63 is controlled based on the measurement data from the feed water thermometer 19, the outside air thermometer 20 a, the atmospheric humidity meter 20 b, and the exhaust gas dew point meter 21 in the same manner as in the above embodiment. Controlled by However, the feed water thermometer 19 is installed downstream of the connection point B of the feed water recirculation line 62 in the main feed water pipe 50, and measures the temperature of the feed water after the feed water recirculation flow from the feed water recirculation line 62 joins. To do.

  When the dew point of the atmosphere is higher than the dew point of the exhaust gas, the control device 22 determines the lower limit value of the feed water temperature from the dew point of the exhaust gas, determines the upper limit value of the feed water temperature from the dew point of the atmosphere, and lower limit values of these feed water temperatures. The target value of the feed water temperature is set within the range between the upper limit value and the upper limit value. Further, when the dew point of the atmosphere is lower than or equal to the dew point of the exhaust gas, the control device 22 sets the target value of the water supply temperature based on the dew point of the exhaust gas, that is, adds a predetermined margin temperature to the dew point of the exhaust gas. To set.

  The control device 22 sets the target value of the feed water temperature as described above, and determines the feed water temperature after joining the feed water recirculation line 62 from the feed water recirculation line 62 measured by the feed water thermometer 19 to the above feed water temperature. In order to control to the target value, the opening of the flow rate control valve 63 of the feed water recirculation line 62 is adjusted, and the feed water supplied from the main feed pipe 50 of the feed water system 16 to the low pressure economizer 37 of the exhaust heat recovery boiler 12. To control the temperature. The target value of the feed water temperature may be a constant value or a value within a predetermined range.

  From the above, according to the present embodiment, the following effects (3) and (4) are obtained.

  (3) Since the heated feed water from the feed water recirculation line 62 is supplied to the low pressure economizer 37 of the exhaust heat recovery boiler 12, the temperature of the feed water and the exhaust gas respectively flowing in and out of the piping in the low pressure economizer 37 The difference can be reduced, the occurrence of condensation on the outer surface of the pipe can be prevented, and corrosion of the pipe can be prevented. In particular, even when the exhaust gas contains a sulfur content, the production of sulfuric acid due to the occurrence of condensation is suppressed, so that corrosion of the pipe can be reliably prevented.

  (4) The feed water temperature supplied to the low-pressure economizer 37 of the exhaust heat recovery boiler 12 is adjusted by the flow rate adjustment valve 63 of the feed water recirculation line 62 adjusting the feed water recirculation flow rate flowing through the feed water recirculation line 62. The temperature is controlled to promote heat exchange with the exhaust gas. As a result, the temperature reduction of the exhaust gas flowing through the exhaust gas flue 38 and the chimney 39 of the exhaust heat recovery boiler 12 is promoted, and the generation of white smoke from the chimney 39 can be suppressed.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this.

  For example, in the second embodiment, the feed water heater 15 of the first embodiment is installed on the downstream side of the junction B of the feed water recirculation line 62, and the feed water heater 15 is further bypassed. A feed water heater bypass line 17 provided with a control valve 18 may be provided, and the opening of the flow rate control valve 18 may be controlled in the same manner as in the first embodiment. In this case, since the feed water flowing through the feed water system 16 is heated by the feed water recirculation flow and the feed water heater 15 by the combination of the first and second embodiments, the capacity of the feed water heater 15 is increased. This can be reduced as compared with the case of the first embodiment.

DESCRIPTION OF SYMBOLS 10 Combined cycle power generation equipment 11 Gas turbine 12 Waste heat recovery boiler 13 Steam turbine 15 Feed water heater 16 Feed water system 17 Feed water heater bypass line 18 Flow rate control valve 19 Feed water thermometer 20a Atmospheric thermometer 20b Atmospheric hygrometer 21 Exhaust gas dew point meter 22 Control device 27 Generator 43 Generator 60 Combined cycle power generation facility 62 Water supply recirculation line 63 Flow control valve

Claims (8)

A combined cycle that includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine, introduces exhaust gas from the gas turbine to the exhaust heat recovery boiler, heats feed water to generate steam, and guides the steam to the steam turbine to generate power In power generation facilities,
A water supply system that includes a water heater that guides the bleed air from the steam turbine and heats the water supply; and a water supply system that supplies the heated water supply to the exhaust heat recovery boiler;
A feed water heater bypass line connected to the feed water system to bypass the feed water heater;
A flow rate adjusting valve for controlling the feed water temperature at the outlet of the feed water heater by adjusting the bypass flow rate provided in the feed water heater bypass line and flowing through the feed water heater bypass line;
A feed water thermometer for measuring a feed water temperature provided downstream of the feed water heater in the feed water system and downstream of a connection point of the feed water heater bypass line; and
An atmospheric thermometer to measure the atmospheric temperature;
An atmospheric hygrometer to measure atmospheric humidity;
An exhaust gas dew point meter for measuring the dew point of the exhaust gas discharged from the exhaust heat recovery boiler;
The target value of the feed water temperature is calculated from the atmospheric dew point and the exhaust gas dew point obtained from the atmospheric temperature and the atmospheric humidity, and the feed water temperature measured by the feed water thermometer is controlled to the target value of the feed water temperature. And a control device for adjusting the opening of the flow control valve . A combined cycle that includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine, introduces exhaust gas from the gas turbine to the exhaust heat recovery boiler, heats feed water to generate steam, and guides the steam to the steam turbine to generate power In power generation facilities,
A water supply recirculation line connected to a water supply system for supplying water to the exhaust heat recovery boiler and recirculating a part of the water supplied by the exhaust heat recovery boiler;
A flow rate adjusting valve that is provided in the feed water recirculation line and controls a feed water temperature supplied from the feed water system to the exhaust heat recovery boiler by adjusting a feed water recirculation flow rate flowing through the feed water recirculation line;
A feed water thermometer for measuring the feed water temperature provided downstream of the connection point of the feed water recirculation line in the feed water system;
An atmospheric thermometer to measure the atmospheric temperature;
An atmospheric hygrometer to measure atmospheric humidity;
An exhaust gas dew point meter for measuring the dew point of the exhaust gas discharged from the exhaust heat recovery boiler;
The target value of the feed water temperature is calculated from the atmospheric dew point and the exhaust gas dew point obtained from the atmospheric temperature and the atmospheric humidity, and the feed water temperature measured by the feed water thermometer is controlled to the target value of the feed water temperature. And a control device for adjusting the opening of the flow control valve. The control device according to claim 1 the dew point of the atmosphere is higher than the dew point of the exhaust gas, characterized in that for setting a target value of the feed water temperature to a value between the dew point of the flue gas dew point of the atmosphere or combined cycle power generating plant according to 2. The control device, when the dew point of the atmosphere is less than or equal to the dew point of the exhaust gas, according to claim 1 or 2, characterized in that set on the basis of the target value of the feed water temperature to the dew point of the flue gas Combined cycle power generation equipment. A combined cycle that includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine, introduces exhaust gas from the gas turbine to the exhaust heat recovery boiler, heats feed water to generate steam, and guides the steam to the steam turbine to generate power In the water heating method for power generation equipment,
A feed water heater that guides extraction from the steam turbine and heats the feed water, and has a feed water system that feeds the heated feed water to the exhaust heat recovery boiler;
The feed water temperature at the outlet of the feed water heater is determined from the dew point of the atmosphere and the exhaust gas by adjusting the bypass flow rate that flows through the feed water heater bypass line that is connected to the feed water system and bypasses the feed water heater. A method for heating a feed water in a combined cycle power generation facility, characterized by controlling the target water temperature to a target value. A combined cycle that includes a gas turbine, an exhaust heat recovery boiler, and a steam turbine, introduces exhaust gas from the gas turbine to the exhaust heat recovery boiler, heats feed water to generate steam, and guides the steam to the steam turbine to generate power In the water heating method for power generation equipment,
Connected to a water supply system for supplying water to the exhaust heat recovery boiler, and having a feed water recirculation line for recirculating a part of the feed water heated by the exhaust heat recovery boiler;
By adjusting the feed water recirculation flow rate flowing through this feed water recirculation line, the feed water temperature supplied from the feed water system to the exhaust heat recovery boiler is determined from the atmospheric dew point and the exhaust gas dew point. A feed water heating method for a combined cycle power generation facility, wherein Target value of the feed water temperature, when the dew point of the atmosphere is higher than the dew point of the exhaust gas, to claim 5 or 6, characterized in that set to a value between the dew point of the flue gas dew point of the atmosphere A feed water heating method for the described combined cycle power generation facility. The combined cycle power generation according to claim 5 or 6 , wherein the target value of the feed water temperature is set based on the dew point of the exhaust gas when the dew point of the atmosphere is lower than or equal to the dew point of the exhaust gas. Water heating method for equipment.

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