JP2007285220A - Combined cycle power generation facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combined cycle power generation facility, in which fuel can be heated up to an appropriate temperature by supplying oil extracted from an exhaust heat recovery boiler even in a low load state. <P>SOLUTION: The combined cycle power generation facility comprises: a gas turbine facility 2; the exhaust heat recovery boiler 1 generating steam by utilizing heat of exhaust gas of the gas turbine facility 2; a steam turbine facility 3 driven by the steam generated in the exhaust heat recovery boiler 1; a power generator 4 driven by the gas turbine facility 2 and the steam turbine facility 3; and a fuel heating/water supply system 30, in which the fuel to be supplied to the gas turbine facility 2 is heated by the water supplied from the exhaust heat recovery boiler 1. The combined cycle power generation facility further comprises a control valve controller 34 receiving output of at least one detector out of a supplied water detector 31, a fuel temperature detector 32, and a power generation load detector 33, to control a supplied water flow control valve 28 disposed to the fuel heating/water supply system 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a combined cycle power generation facility in which a gas turbine and a steam turbine are combined, and relates to a combined cycle power generation facility having an improved fuel heating system for heating before supplying fuel to the gas turbine.

  In recent thermal power plants, combined cycle power generation facilities are becoming the mainstream because of the benefits of improving the thermal efficiency of the plant, being able to start and stop in a short time, and less hot waste water.

  The combined cycle power generation facility is a power generation facility in which a gas turbine facility, a steam turbine facility, and an exhaust heat recovery boiler are combined, and a typical example is shown in FIG. In the combined cycle power generation facility shown in the figure, the air A that is drawn into the gas turbine facility 2 including the air compressor 6, the combustor 7, and the gas turbine 8 from the outside and is brought to high temperature and high pressure by the air compressor 6 is converted into the combustor 7. Thus, it is mixed with the fuel supplied from the fuel system 27 and burned to become combustion gas. This combustion gas is guided to the gas turbine 8, where the gas turbine 8 is driven to rotate by performing expansion work. As a result, the combustion gas loses kinetic energy and becomes high-temperature exhaust gas 9, which is led to the exhaust heat recovery boiler 1 through the exhaust duct 26.

  The exhaust heat recovery boiler 1 includes three types of heat exchangers in the casing 10, that is, a superheater 11, an evaporator 12, and a economizer 13 from the upstream side along the flow of the exhaust gas 9. The steam drum 14 provided in the evaporator 12 is a device for performing gas-liquid separation of the saturated steam generated in the evaporator 12 and maintaining a balance with the saturated steam by maintaining the interior at a predetermined water level. is there. The saturated steam in the steam drum 14 is drawn out by the saturated steam pipe 22, becomes superheated steam through the superheater 11, and is introduced into the steam turbine equipment 3 through the outlet pipe 16.

  The superheated steam guided to the steam turbine facility 3 including the steam turbine 15 performs expansion work in the steam turbine 15 to drive the steam turbine 15 to rotate. The steam that has finished the work is led to the condenser 17 and returned to the water, and further boosted by the feed water pump 20 through the condensate pump 18 and the condensate return pipe 19, and returns to the economizer 13 of the exhaust heat recovery boiler 1 again. . In addition, the gas turbine equipment 2 and the steam turbine equipment 3 have the same drive shaft 5, and the generator 4 is connected to the end.

  Thus, in the combined cycle power generation facility, in order to efficiently use heat, the thermal efficiency is considerably higher than the power generation facility of the gas turbine facility alone or the steam turbine facility alone.

  By the way, the fuel supplied to the gas turbine is preheated and then burned in the gas turbine, so that the amount of heat applied to the fuel during combustion can be reduced, resulting in improvement in the thermal efficiency of the entire plant. This is a well-known technique as described in Patent Document 1. Furthermore, by supplying a large amount of water to the economizer, which is one of the heat exchangers housed in the exhaust heat recovery boiler, part of the heat in the gas turbine exhaust gas that has been released into the atmosphere has been reduced. Further, Patent Document 2 discloses a method for recovering and improving the thermal efficiency of the plant.

  In the combined cycle power generation facility shown in FIG. 9, a heating water supply pipe 24 that branches at the outlet of the economizer 13 and reaches the condenser 17 is provided, and the feed water flow rate is adjusted before the condenser 17 of the heating water supply pipe 24. A valve 28 is provided to control the flow rate of feed water flowing through the heated feed water pipe 24. On the other hand, a fuel heater 25 is provided in the middle of the fuel system 27, and heat is exchanged between the water supplied from the heated water supply pipe 24 and the fuel supplied from the fuel system 27 in the fuel heater 25 to warm the fuel system 27. The generated fuel is guided to the combustor 7 of the gas turbine equipment 2. Further, the feed water cooled by exchanging heat with the fuel is led to the condenser 17 through the heating water supply pipe 24 and is led again to the exhaust heat recovery boiler 1 as the feed water.

  As described in detail in Patent Document 1 and Patent Document 2 described above, hot water heated by an exhaust heat recovery boiler is considered as a heat source for heating the fuel. However, since the exhaust heat recovery boiler uses the exhaust gas discharged from the gas turbine equipment as a heat source, thereby heating the feed water into hot water, it is not possible to supply hot water before the gas turbine equipment is ignited.

  For example, when the fuel is heated using hot water close to normal temperature supplied immediately after the gas turbine is ignited, there are some problems as follows. In other words, depending on the season, the temperature of the fuel heated in the atmosphere may be higher than the temperature of the supplied hot water, which conversely cools the fuel and lowers the thermal efficiency of the power generation equipment. .

  In addition, when a small amount of water contained in the fuel is evaporated and vaporized and is present in the pipe, it is cooled and liquefied, and the water stays as a drain in the fuel system of the gas turbine equipment, In some cases, the fuel system is blocked, and as a result, the supply of fuel is hindered, causing a misfire of the gas turbine.

  Furthermore, depending on the fuel component and the fuel pressure, the fuel temperature has no allowance for its saturation temperature, and when there is a large pressure fluctuation with respect to the fuel, the fuel liquefies and reverses in the combustor of the gas turbine equipment. A fire phenomenon occurs, and in the worst case, the gas turbine is damaged.

  On the other hand, when considering a combined cycle power generation facility in operation, the gas turbine facility naturally performs low load operation during operation in a low load state. Therefore, the flow rate of the supplied fuel is reduced, and as a result, the temperature of the exhaust gas also decreases. Considering the thermal efficiency of the plant, it is ideal that the fuel is heated at a constant temperature regardless of the load state of the gas turbine equipment, that is, the combined cycle power generation equipment. However, when the temperature of the exhaust gas decreases, the temperature in the exhaust heat recovery boiler, which is a heat source for warm water that heats the fuel, decreases. Therefore, during low load operation, the temperature of the fuel cannot be maintained, and the hot water feed water flow rate adjustment valve for heating the fuel is fully opened, making it difficult to control the feed water flow rate.

The control method at the time of a sudden load change during operation or at the time of load interruption in the fuel heating system is described in detail in Patent Document 3 below. There is no description on how to solve the problems related to fuel heating during low-load operation. Further, it is not disclosed in Patent Document 1 and Patent Document 2.
Japanese Patent Laid-Open No. 11-117714 JP-A-2-283803 JP 2000-213374 A

  The present invention has been made based on the above circumstances, and provides a combined cycle power generation facility capable of heating fuel to an appropriate temperature by water supply extracted from an exhaust heat recovery boiler even in a low load state. For the purpose.

  In order to solve the above problems, a combined cycle power generation facility according to the present invention includes a gas turbine facility, an exhaust heat recovery boiler that generates steam using heat of exhaust gas of the gas turbine facility, and an exhaust heat recovery boiler. Steam turbine equipment driven by generated steam, the gas turbine equipment and a generator driven by the steam turbine equipment, and fuel supplied to the gas turbine equipment are heated by water supplied from the exhaust heat recovery boiler A fuel heating water supply system that is provided in the fuel heating water supply system and that measures the temperature of the feed water, and a fuel temperature that is provided in the fuel system of the gas turbine equipment and measures the temperature of the heated fuel At least one of a detector and a power generation load detector for measuring the power generation amount of the generator, the feed water temperature detector, and the fuel temperature sensor. A structure in which and a regulating valve controller for controlling the feed water flow rate control valve provided in the vessel and the power generation load detector of at least one type of output of the detector the fuel heating feed water system.

  ADVANTAGE OF THE INVENTION According to this invention, the combined cycle power generation equipment which can heat a fuel to appropriate temperature with the water supply extracted from the waste heat recovery boiler also in the low load state can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic system diagram showing a combined cycle power generation facility according to an embodiment of the present invention. In FIG. 1, the same parts as those of the prior art are denoted by the same reference numerals and the description thereof is omitted.

  In FIG. 1, a different part from the conventional combined cycle power generation facility (FIG. 9) is provided with a feed water temperature detector 31 for measuring the temperature of feed water flowing in the feed water pipe 24 in the heated feed water pipe 24. A fuel temperature detector 32 for measuring the temperature of the fuel after heat exchange with the water supply in the heating water supply pipe 24 is provided downstream of the heater 25, and a power generation load that detects the load of the power generator 4 coaxially with the power generator 4. A detector 33 is provided, and a control valve controller 34 that outputs signals for controlling the feed water flow rate control valve 28 when signals of these three types of detectors are input is provided. In the present embodiment, the route of the heating water supply pipe 24 branched from the economizer 13, passing through the fuel heater 25, and reaching the condenser 17 via the feed water flow rate adjustment valve 28 is connected to the fuel heating water supply system 30 for convenience. Called. The feed water temperature detector 31, the fuel temperature detector 32, and the power generation load detector 33 may be provided with at least one detector, and the control valve controller 34 has at least one of the above three detectors. What is necessary is just to set it as the structure which inputs the output of a detector.

  The control valve controller 34 stores in advance data such as the optimum water supply temperature, the optimum fuel temperature, and the load amount by the generator at that time, and these data and the actual measured and transmitted by each detector. It has a function to compare the temperature and load amount. The feed water flow rate adjustment valve 28 is controlled by outputting a control signal based on these data.

  Specifically, immediately after the combined cycle power generation facility is activated, the temperature of each heat exchanger in the exhaust heat recovery boiler 1 is not sufficiently increased. Therefore, since the temperature detected by the feed water temperature detector 31 is low, the feed water flow rate control valve 28 remains closed by a signal output as a result of comparison with the data in the control valve controller 34, and the exhaust heat recovery boiler 1. It waits for the temperature rise of each heat exchanger in the inside, especially economizer 13.

  When the load of the combined cycle power generation facility increases and the temperature of each heat exchanger of the exhaust heat recovery boiler 1 increases, the temperature detected by the feed water temperature detector 31 also increases. The feed water flow rate adjustment valve 28 is opened based on a signal output by being compared with the internal data, and the fuel heater 25 starts heat exchange with the fuel. Then, the temperature of the fuel after the heat exchange is sent to the control valve controller 34 through the fuel temperature detector 32, and the control valve controller 34 controls the opening degree of the feed water flow rate control valve 28 so that the actual fuel temperature becomes the optimum temperature. A control signal for outputting is output.

When the load further increases, the temperature of the feed water in the heated feed water pipe 24 further rises, so that the control valve controller 34 does not raise the fuel temperature above a certain temperature based on the signal from the fuel temperature detector 32. Thus, the opening degree of the feed water flow rate adjustment valve 28 is controlled.
By performing such control, the feed water flow rate adjustment valve 28 can be finely controlled based on the feed water temperature, and the combined cycle power generation facility can be stably operated.

(First embodiment)
FIG. 2 is a diagram showing a control valve controller configuration and signal flow of the first example provided in the combined cycle power generation facility of the present embodiment.

  As shown in the figure, the temperature data of the feed water in the heated feed water pipe 24 measured by the feed water temperature detector 31 is transmitted to the control valve controller 34a. The control valve controller 34a compares the data of the water supply temperature setter 36 with the data of the water supply temperature setter 36 and the data from the water supply temperature detector 31 and outputs a control signal. And a controller 38 that receives a signal from the comparator 37 and outputs a signal for controlling the feed water flow rate adjustment valve 28.

  In the control valve controller 34a, the transmitted data of the feed water temperature detector 31 and the preset optimum feed water temperature data output from the feed water temperature setter 36 are input to the comparison calculator 37 for comparison. When the detected temperature is higher than the set temperature, a signal is sent to the controller 38 so as to automatically control the feed water flow rate adjustment valve 28. On the other hand, when the detected temperature is lower than the set temperature, a signal is issued to the controller 38 so that the feed water flow rate adjustment valve 28 is fully closed manually. The optimum temperature data set in the feed water temperature setter 36 is obtained in advance from the relationship between the load state of the combined cycle power generation facility and the feed water temperature, the relationship between the feed water temperature and the fuel temperature after heat exchange, etc. I shall keep it.

  Thus, the control valve controller 34a of the present embodiment controls the feed water flow rate control valve 28 when the load of the combined cycle power generation facility is low and the temperature of the feed water supplied from the exhaust heat recovery boiler 1 to the heated feed water pipe 24 is low. Since the control is performed to close and open the feed water flow rate adjustment valve 28 after the load rises to some extent, the fuel supplied to the gas turbine equipment 2 always exchanges heat with the heated hot water. Therefore, there is no situation where the moisture contained in the fuel is condensed or the fuel itself is condensed, and the power generation facility can be stably operated.

(Second embodiment)
FIG. 3 is a diagram illustrating a configuration and signal flow of the control valve controller of the second example provided in the combined cycle power generation facility of the present embodiment.

  As shown, the generator load measured by the power generation load detector 33, that is, the load data of the entire plant is transmitted to the control valve controller 34b. The control valve controller 34b compares the data of the power generation load setting device 40 with the data of the power generation load setting device 40 having data of the power generation load value set in advance and the data from the power generation load detector 33, and outputs a control signal. And a controller 38 that receives a signal from the comparator 41 and outputs a signal for controlling the feed water flow rate adjustment valve 28.

  In the control valve controller 34b, the transmitted data of the power generation load detector 33 and the data of the power generation load value that is output from the power generation load setting device 40 and that is preset and obtains the optimum feed water temperature are input to the comparison calculator 41. Are compared. When the actually detected power generation load value is larger than the preset load value, a signal is sent to the controller 38 so as to automatically control the feed water flow rate adjustment valve 28. On the other hand, if the actually detected power generation load value is smaller than the set load value, a signal is sent to the controller 38 so that the water supply flow rate adjustment valve 28 is fully closed manually. The optimum power generation load data set in the power generation load setting device 40 is obtained in advance from the relationship between the load state of the combined cycle power generation facility and the temperature of the feed water, the relationship between the temperature of the feed water and the fuel temperature after heat exchange, etc. Shall be kept.

  As described above, the control valve controller 34b of the present embodiment is configured such that the load of the combined cycle power generation facility is low and the supply water flow rate is low when the temperature of the supply water supplied from the exhaust heat recovery boiler 1 to the heated water supply pipe 24 is low. Since the control valve 28 is closed and the control is performed such that the control valve 28 is opened when the load at which the temperature of the feed water is determined to be relatively high rises to some extent. As a result, the water content contained in the fuel does not condense and the fuel itself does not condense, and the power generation facility can be operated stably.

(Third embodiment)
FIG. 4 is a diagram showing a configuration and signal flow of the control valve controller of the third example provided in the combined cycle power generation facility of the present embodiment.

  As shown in the figure, the temperature data of the feed water in the heated feed pipe 24 measured by the feed water temperature detector 31 and the fuel temperature after heat exchange by the fuel heater 25 measured by the fuel temperature detector 32 are shown. Data is transmitted to the control valve controller 34c. The control valve controller 34c compares the data from the feed water temperature detector 31 with the data from the fuel temperature detector 32 and outputs a control signal, and sets the temperature difference data set in advance. Based on the control signal, a temperature difference setting unit 44 to be stored, a second comparison operation unit 45 that compares the data of the temperature difference setting unit 44 with the data from the first comparison operation unit 43 and outputs a control signal. And a regulator 38 for controlling the feed water flow rate regulating valve 28.

  In the control valve controller 34c, the transmitted data of the feed water temperature detector 31 and the data of the fuel temperature detector 32 are input to the first comparison calculator 43 and compared, and the difference value is output. The output difference value is input to the second comparison calculator 45 and compared with temperature difference data set in advance by the temperature difference setting unit 44. When the actually detected feed water temperature is higher than the actually detected fuel temperature by the temperature difference set by the temperature difference setting unit 44, a signal is issued so as to automatically control the feed water flow rate adjustment valve 28. On the other hand, if the temperature difference is lower, a signal for manually closing the feed water flow rate adjustment valve 28 is issued. The optimum temperature difference data set in the temperature difference setting unit 44 is obtained in advance from the relationship between the load state of the combined cycle power generation facility and the temperature of the feed water, the relationship between the temperature of the feed water and the fuel temperature after heat exchange, etc. Shall be kept.

  As described above, the control valve controller 34c of the present embodiment closes the water supply flow rate control valve 28 when the temperature difference is small, based on the difference between the temperature of the water supply for heating the fuel and the temperature of the fuel after the heating. Since the feed water flow rate adjustment valve 28 is opened when the temperature becomes higher than that of the fuel and a certain temperature difference occurs, the fuel supplied to the gas turbine equipment 2 can always maintain a state of receiving heat from the feed water. This eliminates the situation where moisture contained in the water or the fuel itself condenses, and enables stable operation of the power generation equipment.

(Fourth embodiment)
FIG. 5 is a diagram showing a configuration and signal flow of a control valve controller of a fourth example provided in the combined cycle power generation facility of the present embodiment.

  As shown in the figure, the temperature data of the feed water in the heated feed pipe 24 measured by the feed water temperature detector 31 and the fuel temperature after heat exchange by the fuel heater 25 measured by the fuel temperature detector 32 are shown. Data is transmitted to the control valve controller 34d. The control valve controller 34d transmits the data transmitted from the feed water temperature detector 31 to the fuel temperature calculator 47 in which the relationship between the feed water temperature and the optimum fuel temperature is stored in advance, and is transmitted from the fuel temperature detector 32. A first comparison calculator 48 that compares the measured data with the data from the fuel temperature calculator 47 and outputs a control signal for matching the two values, and a fuel temperature that stores a predetermined upper limit value of the fuel temperature When the fuel temperature actually measured by comparing the setting device 49 with the data of the fuel temperature setting device 49 and the data transmitted from the fuel temperature detector 32 is higher than the upper limit value set by the fuel temperature setting device 49 Output from the second comparison calculator 50 and the first comparison calculator 48 are X signals, the output from the fuel temperature setter 49 is a Y signal, and the second comparison calculator 50 And a signal switching unit 51 that outputs a Y signal when there is an input from the second comparison calculator 50 and outputs an X signal otherwise, and this signal switching. And a controller 52 that controls the feed water flow rate adjustment valve 28 based on the output from the vessel 51.

  In the control valve controller 34 d, the temperature of the feed water in the heated feed pipe 24 actually measured by the feed water temperature detector 31 is input to the fuel temperature calculator 47. In the fuel temperature calculator 47, as shown in FIG. 6, the relationship between the feed water temperature and the optimum fuel temperature is stored as data. That is, the fuel temperature data obtained by subtracting a certain difference value a (° C.) from the input water temperature Tw (° C.) is output as the optimum fuel temperature. However, the output fuel temperature is not always proportional to the feed water temperature, but the upper limit value of the fuel temperature is determined (Tp (° C. in FIG. 6)). Is output.

  The output from the fuel temperature calculator 47 and the output from the fuel temperature detector 32, which is the actually measured fuel temperature, are compared by the first comparison calculator 48. An identical control signal is sent to the signal switch 51 as an X signal. On the other hand, the signal from the fuel temperature detector 32 is branched and sent to the second comparator 50, where it is compared with the output of the fuel temperature setter 49 that outputs the preset upper limit value of the fuel temperature, When the actual fuel temperature is higher than the set upper limit value, a switching signal is sent to the signal switching device 51. The signal from the fuel temperature setting device 49 is also input as the Y signal from the signal switching device 51 at the same time.

  The signal switching unit 51 normally uses the input X signal, that is, the output from the first comparison computing unit 48 as an output signal as it is, but if there is a switching signal from the second comparison computing unit 50, Y The output of the fuel temperature setter 49 input as a signal is used as an output signal. Based on these signals, the controller 52 controls the feed water flow rate adjustment valve 28.

  FIG. 7 shows the relationship between the fuel temperature and the feed water temperature with respect to the power generation load when the control valve controller 34d of this embodiment performs the control. The temperature of the feed water depends on the temperature of each heat exchanger of the exhaust heat recovery boiler 1, particularly the economizer 13. Therefore, since the exhaust temperature of the gas turbine increases when the power generation load increases, the amount of heat recovered by the exhaust heat recovery boiler 1 naturally increases. Therefore, the feed water temperature rises corresponding to the power generation load. On the other hand, the fuel temperature rises while maintaining a certain difference value a from the feed water temperature up to a certain feed water temperature. However, in the control by the control valve controller 34d of this embodiment, an upper limit value Tp of the fuel temperature is set, and the fuel temperature is increased. Prevents unnecessary rise in temperature. Therefore, the fuel can be supplied to the turbine under optimum conditions without being heated more than necessary.

  Note that the data on the relationship between the feed water temperature stored in the fuel temperature calculator 47 and the optimum fuel temperature corresponding thereto, and the upper limit value of the fuel temperature set in the fuel temperature calculator 47 and the fuel temperature setter 49 are based on a simulation or the like in advance. It is determined from the relationship between the load state of the combined cycle power generation facility and the temperature of the feed water, the relationship between the temperature of the feed water and the fuel temperature after heat exchange, the gas turbine combustion state depending on the fuel temperature, and the like.

  As described above, the control valve controller 34d of this embodiment sets a certain proportional relationship between the temperature of the feed water that heats the fuel and the temperature of the heated fuel, and the feed water flow rate control valve 28 is set based on this relationship. Therefore, the fuel supplied to the gas turbine equipment 2 can always be maintained in a state of receiving heat from the feed water, and the situation where it is heated more than necessary is eliminated, so that the power generation equipment can be stably operated.

(Fifth embodiment)
FIG. 8 is a diagram showing a configuration and signal flow of the control valve controller of the fifth example provided in the combined cycle power generation facility of the present embodiment.

  As shown in the figure, the temperature data of the feed water in the heated feed pipe 24 measured by the feed water temperature detector 31 and the temperature data of the fuel after heat exchange by the fuel heater 25 measured by the fuel temperature detector 32 are shown. Are transmitted to the control valve controller 34e. The control valve controller 34e compares the data transmitted from the feed water temperature detector 31 with the preset feed water temperature value and the feed water temperature setter 36 for storing data of a predetermined feed water temperature. The first comparison calculator 53 that issues a switching signal when the measured feed water temperature is high, stores data on the relationship between the feed water temperature and the optimum fuel temperature, and the data from the feed water temperature detector 31 branches. An input fuel temperature calculator 47, a second comparison calculator 54 that compares the data transmitted from the fuel temperature detector 32 with the data from the fuel temperature calculator 47 and generates a control signal that matches the two, The output from the fully closed signal generator 55 that always issues the control signal for fully closing the feed water flow rate control valve 28 and the second comparator 54 is the X signal, and the output from the fully closed signal generator 55 is the Y signal. In addition, the output from the first comparison calculator 53 is input, and if there is an output from the first comparison calculator 53, the output is the X signal, that is, the second comparison calculator 53. If there is no output, the output is the Y signal, that is, the signal switch 56 that outputs the output from the fully closed signal generator 55 as it is, and the output from the signal switch 56 is the X signal. In some cases, a control signal is sent to the feed water flow rate adjusting valve 28, and in the case of a Y signal, the controller 38 is configured to send a signal for manually closing the feed water flow rate regulating valve 28.

  In the control valve controller 34 e, the temperature of the water supply in the heated water supply pipe 24 measured by the water supply temperature detector 31 is input to the first comparison calculator 53. The first comparison calculator 53 also receives a signal from the feed water temperature setter 36 that stores a preset feed water temperature value, and the two are compared here. When the measured actual feed water temperature is higher than the preset feed water temperature, a switching signal is output to the signal switch 56. Further, the signal from the feed water temperature detector 31 is branched and input to the fuel temperature calculator 47. The fuel temperature calculator 47 stores the relationship between the feed water temperature and the optimum fuel temperature as data, and calculates the optimum fuel temperature with respect to the feed water temperature input from the feed water temperature detector 31.

  The output from the fuel temperature calculator 47 and the output from the fuel temperature detector 32, which is the actually measured fuel temperature, are compared by the second comparison calculator 54, and both outputs are the same in the comparison calculator 54. The control signal is sent to the signal switch 56 as an X signal so that On the other hand, the signal from the fully closed signal generator 55 is sent to the signal switch 56 as a Y signal.

  When the signal from the first comparison calculator 53 is input, the signal switch 56 outputs the X signal, that is, the output from the second comparison calculator 54, and the first comparison calculator 53. If no signal is input, the Y signal, that is, the output from the fully closed signal generator 55 is used. When the input is an X signal, the controller 38 outputs a signal for automatically controlling the water supply flow rate adjustment valve 28 based on the signal, and when the input is a Y signal, the controller 38 manually controls the water supply flow rate adjustment valve 28. Outputs a closing signal.

  It should be noted that the relationship between the water supply temperature set in the fuel temperature calculator 47 and the optimum fuel temperature and the value of the water supply temperature set in the water supply temperature setter 36 are determined in advance by comparing the load state of the combined cycle power generation facility and the water supply by simulation or the like. It is obtained from the temperature relationship, the relationship between the temperature of the feed water and the fuel temperature after heat exchange, the gas turbine combustion state depending on the fuel temperature, and the like.

  As described above, the control valve controller 34e of the present embodiment determines the lower limit of the temperature of the feed water, sets a certain proportional relationship between the temperature of the heated fuel and the temperature of the feed water that warms the fuel, and supplies the water based thereon. The flow control valve 28 is controlled. As a result, the fuel supplied to the gas turbine facility 2 can always be maintained in a state of receiving heat from the water supply, and the situation where it is heated more than necessary is eliminated, and the power generation facility can be operated stably.

  According to this embodiment, even when the combined cycle power generation facility is in a low load state, the temperature of each heat exchanger in the exhaust heat recovery boiler is low, and the temperature of the feed water for heating the gas turbine fuel is low, the fuel is cooled. Can prevent the phenomenon that the moisture contained in the fuel is condensed or the fuel itself is condensed, preventing the misfire and flashback in the combustor of the gas turbine equipment, As a result, the combined cycle power generation facility can be stably operated. Furthermore, even when the temperature of the feed water is low and the set temperature of the gas turbine fuel is high, the phenomenon that the feed water flow rate control valve is fully opened can be prevented, and the combined cycle power generation facility can be stably operated.

The figure which shows the structure of the combined cycle power generation equipment of embodiment of this invention. The figure which shows the structure and signal flow of the control valve controller of the 1st Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure which shows the structure and signal flow of the control valve controller of the 2nd Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure which shows the structure and signal flow of the control valve controller of the 3rd Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure which shows the structure and signal flow of the control valve controller of the 4th Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure explaining operation | movement of the fuel temperature calculator which comprises the control valve controller of the 4th Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure explaining operation | movement of the control valve controller of the 4th Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure which shows the structure and signal flow of the control valve controller of the 5th Example with which the combined cycle power generation equipment of embodiment of this invention is equipped. The figure which shows the structure of the conventional combined cycle power generation equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Waste heat recovery boiler, 2 ... Gas turbine equipment, 3 ... Steam turbine equipment, 4 ... Generator, 5 ... Drive shaft, 6 ... Air compressor, 7 ... Combustor, 8 ... Gas turbine, 9 ... Exhaust gas, DESCRIPTION OF SYMBOLS 10 ... Waste heat recovery boiler casing, 11 ... Superheater, 12 ... Evaporator, 13 ... Carbon-saving device, 14 ... Steam drum, 15 ... Steam turbine, 16 ... Superheater outlet piping, 17 ... Condenser, 18 ... Recovery Water pump, 19 ... Condensate return pipe, 20 ... Feed water pump, 22 ... Saturated steam pipe, 24 ... Heated water pipe, 25 ... Fuel heater, 26 ... Exhaust duct, 27 ... Fuel system, 28 ... Feed water flow control valve, DESCRIPTION OF SYMBOLS 30 ... Fuel heating water supply system, 31 ... Feed water temperature detector, 32 ... Fuel temperature detector, 33 ... Electric power generation load detector, 34, 34a, 34b, 34c, 34d, 34e ... Control valve controller, 36 ... Feed water temperature setting device 37, 41, 43, 45, 48, 0, 53, 54 ... comparison calculator, 38 ... controller, 40 ... power generation load setter, 44 ... temperature difference setter, 47 ... fuel temperature calculator, 49 ... fuel temperature setter, 51 ... signal switcher, 52 ... Controller, 55 ... Fully closed signal generator, 56 ... Signal switcher, A ... Air, Tp ... Fuel temperature upper limit.

Claims (8)

  Gas turbine equipment, exhaust heat recovery boiler that generates steam using heat of exhaust gas of the gas turbine equipment, steam turbine equipment driven by steam generated in the exhaust heat recovery boiler, and gas turbine equipment And a generator driven by the steam turbine equipment, and a fuel heating / water supply system for heating fuel supplied to the gas turbine equipment by feed water supplied from the exhaust heat recovery boiler, provided in the fuel heating / water supply system A feed water temperature detector that measures the temperature of the feed water, a fuel temperature detector that is provided in a fuel system of the gas turbine equipment and that measures the temperature of the heated fuel, and a power generation load detector that measures the amount of power generated by the generator And at least one detector of the feed water temperature detector, the fuel temperature detector, and the power generation load detector. Combined cycle power plant, characterized in that it comprises a regulating valve controller for controlling the feed water flow rate control valve provided in said fuel heating feed water system.   The control valve controller compares an input value from the feed water temperature detector with a predetermined feed water temperature, and if the input value from the feed water temperature detector is higher than the predetermined feed water temperature, the control valve controller controls the feed water flow rate control valve. 2. The combined cycle power generation facility according to claim 1, wherein the combined cycle power generation equipment is controlled automatically and closes the feed water flow rate adjustment valve when an input value from the feed water temperature detector is lower than the predetermined feed water temperature.   The control valve controller compares an input value from the power generation load detector with a predetermined power generation load value, and if the input value from the power generation load detector is larger than the predetermined power generation load value, the feed water flow rate adjustment 2. The combined cycle power generation according to claim 1, wherein the valve is automatically controlled, and the feed water flow rate adjustment valve is closed when an input value from the power generation load detector is smaller than the predetermined power generation load value. Facility.   The control valve controller compares an input value from the feed water temperature detector with an input value from the fuel temperature detector, and calculates an input value from the fuel temperature detector from an input value from the feed water temperature detector. When the subtracted value is larger than a predetermined value, the feed water flow rate control valve is automatically controlled, and a value obtained by subtracting the input value from the fuel temperature detector from the input value from the feed water temperature detector is the predetermined value. The combined cycle power generation facility according to claim 1, wherein when it is smaller than the value, the feed water flow rate adjustment valve is closed.   The control valve controller includes a fuel temperature calculator that outputs a fuel temperature having a predetermined difference with respect to an input value from the feed water temperature detector, an input value from the fuel temperature detector, and a fuel temperature calculator. A first comparison calculator that compares the output values and outputs a control signal for matching them, an input value from the fuel temperature detector, and a temperature from a fuel temperature setter that outputs a predetermined fuel temperature. A second comparison calculator that outputs a signal when the input value from the fuel temperature detector is higher than the temperature set by the fuel temperature setter, and the output of the first comparator is an X signal. The output of the fuel temperature setting device is input as a Y signal, the output of the second comparison arithmetic unit is input as a switching signal, and when there is an input of the switching signal, the output is converted from the X signal. Signal off to switch to Y signal Vessels and, combined cycle power plant according to claim 1, characterized in that it comprises an adjustment gauge for adjusting the flow rate control valve by the output of the signal switching device.   When the input value from the feed water temperature detector is TW1, the input value from the fuel temperature detector is TF1, the difference value is a1, and the predetermined fuel temperature is TP1, the X signal is TF1 = TW1-a1. 6. The combined cycle power generation facility according to claim 5, wherein the Y signal is a control signal for setting TF1 = TP1.   The control valve controller compares an input value from the feed water temperature detector with a temperature from a feed water temperature setter that outputs a predetermined feed water temperature, and an input value from the feed water temperature detector is obtained from the feed water temperature setter. A first comparison calculator that outputs a signal when the temperature is higher than the temperature of the fuel, and a fuel temperature that outputs a temperature value obtained by subtracting a predetermined difference value from the input feed water temperature value by inputting the output of the feed water temperature detector A calculator, a second comparator for comparing the input value from the fuel temperature detector and the output value of the fuel temperature calculator, and outputting a control signal for matching the two, and outputting a fully closed signal The output of the fully closed signal generator and the output of the second comparison calculator are input as an X signal, the output of the fully closed signal generator is input as a Y signal, and the output of the first comparison calculator is switched. When input as a signal and there is the switching signal Automatically outputs the X signal, and when there is no switching signal, outputs a Y signal, and when the output from the signal switching device is the X signal, automatically controls the feed water flow rate control valve, The combined cycle power generation facility according to claim 1, further comprising a controller for closing the water supply flow rate control valve. When the input value from the feed water temperature detector is TW2, the input value from the fuel temperature detector is TF2, and the difference value is a2, the X signal is a control signal for setting TF2 = TW2-a2. The combined cycle power generation facility according to claim 7.

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