JP5334885B2 - Boiler heat recovery apparatus and heat recovery method in power generation facilities - Google Patents

Description

  The present invention relates to, for example, a boiler heat recovery apparatus and a heat recovery method in a thermal power generation facility.

  Generally, a thermal power generation facility includes a boiler that heats water to make steam, a steam turbine that is driven by steam generated by the boiler, a generator that generates power by being driven by the steam turbine, and a steam turbine For cooling the steam discharged from the boiler into water (saturated water), a feed water pump for supplying the water obtained by the condenser to the boiler, and a circulation for supplying cooling water to the condenser With a pump.

  That is, this type of thermal power generation facility supplies a boiler with water from a condensate system connecting the condenser and the feed water pump, and water from the condensate system in order to send the water obtained by the condenser to the feed water pump. Therefore, the water supply system connecting the water supply pump and the boiler, the steam generated by the boiler is supplied to the steam turbine, and the steam discharged from the steam turbine is sent to the condenser through the steam turbine. And a steam system connecting the vessel.

  The condensate system includes a demineralizer for removing impurities contained in the water obtained by the condenser, a condensate pump for sending the water obtained by the condenser to the demineralizer, and a demineralizer And a condensate booster pump that sends water from the water supply pump toward the water supply pump (see, for example, Patent Documents 1 and 2).

  Two or more condensate pumps and condensate booster pumps are provided. That is, two or more condensate pumps and condensate booster pumps are provided so that the required amount of water obtained from the condenser can be stably sent to the feed pump.

  And the power supply voltage of the condensate pump is set to be lower than the power supply voltage of the condensate booster pump. Specifically, the condensate system is equipped with a demineralizer tower in the upstream (upstream side) of the condensate booster pump, which has a greater pressure loss than the condenser. Since the water pressure decreases when passing through the desalting tower, a condensate lifting pump is installed on the downstream side of the desalting tower. As a result, the condensate system compensates for a decrease in water pressure by the condensate booster pump, and can stably send water (treated water) from the desalting tower to the feedwater pump.

  In the condensate system, the load of each pump during operation is different due to the difference in the installation location of the condensate pump and the condensate booster pump (the condensate booster pump load is greater than the condensate pump load). Therefore, the power supply voltage of the condensate booster pump is usually set to be higher than the power supply voltage of the condensate pump in consideration of the current at start-up and normal operation, for example, the power supply of the condensate pump is 440V In this case, the power supply of the condensate booster pump is set to 6600V.

  Here, the operation (start-up) procedure of the thermal power generation facility will be described. In the start-up operation for starting the operation, first, the circulation system is driven and then the condensate system is driven. In other words, after the circulation pump is driven and cooling water is supplied to the condenser, the condensate pump is driven and a part (for example, one) of the condensate booster pumps of the two or more condensate booster pumps is driven. The pump is driven and the water in the condenser is sent to the downstream side to increase the degree of vacuum in the condenser. That is, the condensate pump and the condensate booster pump are driven to feed the water in the condenser downstream, thereby operating the ejector provided in the condensate system and increasing the vacuum of the condenser. .

  And when the vacuum degree of a condenser reaches predetermined | prescribed vacuum degree, a water supply pump will be driven and the water from a condensate system will be supplied to a boiler. If it does so, water will accumulate in a boiler and the water turns into steam and is supplied to a steam system. Thereby, a steam turbine drives, a generator starts electric power generation, and the steam discharged | emitted from the steam turbine is sent to a condenser.

  Then, when the generator starts to generate electricity in this way, the output of the generator gradually increases, and when the output reaches the lower limit value of the low output range lower than the rated output range, Power transmission is started. Along with this, the load (output) of the generator will gradually increase. Therefore, in the condensate system, the water in the condenser is sent to the feed pump with the amount of water corresponding to the output of the generator. Make the degree of vacuum correspond to the output (load) of the generator.

  As a result, in the condensate system, if the generator output deviates from the low output range lower than the rated output range (when the output value is preset in the rated output range), the number of condensate booster pumps to be driven increases. The water in the condenser is supplied to the feed pump with the amount of water corresponding to the output of the generator, and the rated operation is performed.

  On the other hand, in the stop operation in which the operation is stopped, the thermal power generation facility gradually reduces the steam supplied from the boiler to the steam turbine to reduce the output of the generator, and the output departs from the rated output range to reduce the output. When entering the zone, a part of the condensate booster pumps is stopped to reduce the number of condensate booster pumps driven, and the same number of condensate booster pumps as in the start-up operation are continuously driven.

  When the output of the generator reaches the lower limit of the low output range, the power transmission to the transmission line is stopped (disconnected state), and the generator output cannot be transmitted (the parallel state cannot be maintained). After that, the remaining condensate pump and condensate booster pump are stopped.

  Moreover, in the boiler which is a steam generation apparatus of a thermal power generation facility, a heat recovery apparatus that recovers the drain generated in the boiler to be reused is provided. For example, a startup system of a boiler, that is, a system in which a flash tank is provided between a condenser and a boiler, and steam generated by the flash tank when the unit is started is introduced into a high-pressure feed water heater to recover heat is known. (Patent Document 3).

  In this type of heat recovery apparatus, the temperature of feed water to the boiler is increased by introducing steam from the flash tank to the high-pressure feed water heater. That is, when the plant is started, the temperature of the steam is raised by the flash tank while the turbine can be extracted.

  The high-pressure and low-pressure feed water heaters are supplied with turbine bleed gas from the steam turbine to raise the feed water and condensate temperature, and the introduced turbine bleed gas is condensed by heat exchange with the feed water and condensate. It is configured to be drained water and collected in a condenser or a deaerator.

JP 2008-261316 A JP 2008-261317 A Japanese Patent Laid-Open No. 10-317916

  However, in the case of the conventional heat recovery device, the steam generated in the flash tank is recovered by the high-pressure heater and the condenser at a ratio of 7: 3 until it becomes a parallel state. There is a problem that the rate of heat recovery is relatively large and the efficiency of heat recovery is low.

  Accordingly, an object of the present invention is to provide a heat recovery apparatus and a heat recovery method for a boiler in a power generation facility that can efficiently recover heat generated from a flash tank when the generator is started.

  The boiler heat recovery apparatus in the power generation facility according to the present invention is a flash tank that raises the temperature of the feed water to the boiler 10 together with the high-pressure feed water heater 70 in the low output range where the output of the generator 30 is lower than the rated output range. 90, the first steam valve B3 provided in the steam line S1 that connects the flash tank 90 and the high-pressure heater 70c of the high-pressure feed water heater 70, and the steam pipe that connects the flash tank 90 and the condenser 40 In the heat recovery device for the boiler in the power generation facility provided with the second steam valve B4 provided in the path S2, the valve opening degree of the first steam valve B3 is the second steam valve B4 before reaching the low output range. The valve opening of the second steam valve B4 is controlled to be higher than the above setting at the time when the low output region is set and the pressure drop of the flash tank 90 is detected. Characterized in that it is.

  In this case, since the opening degree of the first steam valve B3 was controlled to be set higher than the opening degree of the second steam valve B4 before reaching the low output range, most of the generated in the flash tank 90. Can be recovered by the high-pressure heater 70c, and the efficiency of heat recovery is improved. Further, when the pressure drop of the flash tank 90 is detected, that is, when the pressure of the flash tank 90 is reduced when the pressure drop of the flash tank 90 is reduced, the valve opening degree of the second steam valve B4 is Since the second steam valve B4 is controlled to be higher than the set value, the second steam valve B4 can be prevented from being closed, and the steam generated in the flash tank 90 can be recovered by the high-pressure heater 70c and the condenser 40. it can.

  Moreover, the heat recovery method for the boiler in the power generation facility according to the present invention raises the feed water temperature to the boiler 10 together with the high-pressure feed water heater 70 in the low output region where the output of the generator 30 is lower than the rated output region. The flash tank 90, the first steam valve B3 provided in the steam line S1 connecting the flash tank 90 and the high-pressure heater 70c included in the high-pressure feed water heater 70, and the flash tank 90 and the condenser 40 are connected. In the heat recovery method of the boiler in the power generation facility provided with the second steam valve B4 provided in the steam line S2, before reaching the low output region, the ratio of the valve opening degree of the first steam valve B3 is set to The valve opening of the second steam valve B4 is set higher than the valve opening of the second steam valve B4, becomes the low output region, and when the pressure drop of the flash tank 90 is detected, the valve opening of the second steam valve B4 becomes higher than the above setting. Yo Characterized in that the.

  As described above, according to the present invention, the valve opening of the first steam valve is set to be smaller than the valve opening of the second steam valve before the output of the generator reaches a low output range lower than the rated output range. On the other hand, the valve opening of the second steam valve was made higher than the above setting when the low output range was reached and a pressure drop in the flash tank was detected. It is possible to achieve an excellent effect that the steam can be efficiently recovered by heat.

1 shows a schematic conceptual diagram of a thermal power generation facility according to an embodiment of the present invention. The conceptual diagram of the condensate and water supply system of the thermal power generation equipment which concerns on the embodiment is shown.

  Hereinafter, a thermal power generation facility according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, such a thermal power generation facility includes a boiler 10 that heats water into steam, steam turbines 20, 21, 22, 23 driven by steam generated in the boiler 10, and the steam turbine 20. , 21, 22, 23 to generate electric power, and a condenser 40 for cooling the steam discharged from the steam turbines 20, 21, 22, 23 into water (saturated water), A water supply pump 50 that supplies the water obtained by the condenser 40 to the boiler 10 and a circulation pump 80 that supplies cooling water to the condenser 40 are provided.

  That is, the thermal power generation facility 1 includes a condensate system WLa that connects the condenser 40 and the water supply pump 50 and water from the condensate system WLa in order to send the water obtained by the condenser 40 to the water supply pump 50. Is supplied to the boiler 10, the water supply system WLb connecting the water supply pump 50 and the boiler 10, and the steam generated in the boiler 10 is supplied to the steam turbines 20, 21, 22, 23, and the steam turbines 20, 21, In order to send the steam discharged from 22 and 23 to the condenser 40, a steam system SL that connects the boiler 10 and the condenser 40 via the steam turbines 20, 21, 22, and 23 is provided.

  The boiler 10 includes an evaporator 11 that evaporates water supplied from the water supply system WLb, first and second superheaters 12a and 12b that superheat saturated steam evaporated by the evaporator 11, and an evaporation turbine (described later). And a reheater 13 that superheats exhaust gas (steam) from the high-pressure turbine 20. The boiler 10 according to the present embodiment supplies the steam superheated by the first and second superheaters 12a and 12b to the steam turbine (high pressure turbine) 20 and the steam superheated by the reheater 13 as another steam turbine. (Medium-pressure turbine described later) 21 is supplied.

  The thermal power generation facility 1 according to the present embodiment includes a high-pressure turbine 20, an intermediate-pressure turbine 21, and low-pressure turbines 22 and 23 as steam turbines 20, 21, 22, and 23. The high-pressure turbine 20 and the intermediate-pressure turbine 21 are One unit is provided, and two low-pressure turbines 22 and 23 are provided.

  These steam turbines 20, 21, 22, and 23 are arranged in parallel so that the respective output shafts are coaxial in the order of the high-pressure turbine 20, the intermediate-pressure turbine 21, and the low-pressure turbines 22 and 23. It is connected to output shafts of adjacent steam turbines 20, 21, 22 and 23. The generator 30 is arranged side by side with respect to the steam turbines 20, 21, 22, and 23, and the input shaft is connected to the output shaft of the low-pressure turbine 23. Thereby, the generator 30 receives the drive of the high pressure turbine 20, the intermediate pressure turbine 21, and the low pressure turbines 22 and 23 to generate power.

  The condenser 40 cools the exhaust (steam) of the steam turbines 22 and 23 into water, and in this embodiment, steam from the steam turbines 22 and 23 (low-pressure turbines 22 and 23) is introduced. The steam introduced into the housing 400 is provided with a housing 400 that defines an internal space that is defined, and a cooling pipe (not shown) that is disposed in the housing 400 and that circulates the cooling water from the circulation system RL. Is indirectly cooled by cooling water in the cooling pipe, thereby condensing the steam into water. That is, the surface condenser is employ | adopted for the condenser 40 which concerns on this embodiment.

  Although not shown, two or more of the water supply pumps 50 are actually provided, and some of the water supply pumps are electrically driven pumps, and the remaining water supply pumps are driven by steam. It consists of a steam turbine pump.

  The electric water supply pump is driven when the output of the generator 30 is less than the output value set in the low output range (hereinafter referred to as the LLO range) lower than the rated output range. On the other hand, the steam-driven feed water pump is driven when the output of the generator 30 is equal to or higher than the output value set in the LLO region. Here, the “rated output range” means an output range during rated (stable) operation of the generator 30, which is a design specification of the thermal power generation facility 1.

  Here, the systems WLa, WLb, SL, and RL will be described in detail. Each system WLa, WLb, SL, RL is divided based on the boiler 10, the condenser 40, and the feed water pump 50.

  As shown in FIG. 2, the condensate system WLa includes impurities contained in water obtained by a condenser 40 that returns steam discharged from the steam turbines 20, 21, 22, and 23 that drive the generator 30 to water. A demineralization tower 52 for removing water, a condensate pump 53 for sending water in the condenser 40 to the demineralization tower 52, and a boiler 10 for generating steam to be supplied to the steam turbines 20, 21, 22, 23 A condensate booster pump 54 that feeds water in the desalting tower 52 to a feed water pump 50 that supplies water is provided.

  Further, the condensate system WLa is arranged on the downstream side of the condensate booster pump 54 (between the condensate booster pump 54 and the feed water pump 50) and the water obtained by the condenser 40 and the steam turbines 20, 21, 22, and 22. 23, a condensate heat exchanger 55 that exchanges heat with water used as bearing cooling water, an ejector 56 that extracts internal air to maintain the vacuum degree of the condenser 40, steam turbines 20, 21, A ground condenser 57 that exchanges heat with the shaft seal water of 22 and 23, a drain cooler 58 that cools the drain to prevent heat recovery and flushing, and low-pressure feed water heating that heats the water by extraction from the steam turbines 20, 21, 22, and 23 A vessel 59, a deaerator 60 and the like for directly heating water with steam and physically separating and removing dissolved gas contained in the water are provided. The low-pressure feed water heater 59 has first to fourth low-pressure heaters 59a to 59d.

  The water supply system WLb includes a high-pressure feed water heater 70 that heats the water sent out by the feed water pump 50 by extraction from the steam turbines 20, 21, 22, and 23. Moreover, the high-pressure feed water heater 70 has sixth to eighth high-pressure heaters 70a to 70c.

  Then, in the low output range lower than the rated output range of the generator 30, the flash tank 90 for raising the temperature of the steam together with the high pressure feed water heater 70 and the low pressure feed water heater 59 until the start of turbine extraction. Is provided in the startup system of the boiler 10. The input part of the flash tank 90 is connected to the primary superheater 12a and the secondary superheater 12b, and water is introduced into the flash tank 90 from the primary superheater 12a and the secondary superheater 12b. The output part of the flash tank 90 is connected to the eighth high-pressure heater 70c of the high-pressure feed water heater 70 and the condenser 40, and the steam heated by the flash tank 90 is converted into the condenser 40, the eighth high-pressure heater. It is collected in any one of 70c.

  More specifically, the input unit of the flash tank 90 and the primary superheater 12a and the secondary superheater 12b of the boiler 10 are connected by the first water supply line W1 and the second water supply line W2, and the flash tank 90 is connected. The output section (steam system) is connected to the high-pressure feed water heater 70 and the condenser 40 through the first and second steam supply pipes S1 and S2. Moreover, the output part (steam system | strain) of the flash tank 90 and the secondary superheater 12b of the boiler 10 are connected by ventilation line S3. Moreover, the output part (drain system) of the flash tank 90 and the deaerator 60 are connected by a drain supply pipe D1. Further, the turbines 20 to 23 and the high-pressure feed water heater 70 are connected by an extraction pipe (not shown). Further, a bypass line SL6 of the turbines 20 to 23, which will be described later, and an eighth high-pressure heater 70c of the high-pressure feed water heater 70 are connected by a steam recovery line (not shown).

  Then, bypass valves B1 and B2 are provided in the first and second water supply pipes W1 and W2, respectively. In addition, a first steam valve B3 is provided in the first steam supply line S1, and a second steam valve B4 is provided in the second steam supply line S2. When the pressure of the flash tank 90 reaches 0.69 MPa or more, the first steam valve B3 starts to open with an upper limit of 90%, and is controlled to open until the pressure of the flash tank 90 reaches 3.5 MPa. The second steam valve B4 is configured to be fully closed when the generator 30 is in a parallel state and the pressure of the flash tank 90 decreases. Further, a ventilation valve B5 is provided in the ventilation pipe line S3. A heating drain valve B6 is provided in the drain supply pipe D1.

  Returning to FIG. 1, the steam system SL includes a first steam pipe that connects the boiler 10 and the intake side of the high-pressure turbine 20 on the assumption that the steam turbines 20, 21, 22, and 23 are arranged as described above. A second steam line SL2 connecting the path SL1, the exhaust side of the high-pressure turbine 20 and the reheater 13 in the boiler 10, and a third steam line connecting the reheater 13 and the intake side of the intermediate pressure turbine 21. SL3, a fourth steam pipe SL4 connecting the exhaust side of the intermediate pressure turbine 21 and the intake side of the low pressure turbines 22, 23, and a fifth steam pipe connecting the exhaust side of the low pressure turbines 22, 23 to the condenser 40. A road SL5 is provided.

  In addition, the steam system SL of the thermal power generation facility 1 according to the present embodiment is connected to the steam line SL1 to SL5 and the valve B from the first steam line SL1 that connects the boiler 10 and the high-pressure turbine 20. A bypass pipe SL6 that branches and connects to the condenser 40 is provided.

  The circulation system RL includes a water intake path 81 connected to a water source (the sea in this embodiment), a circulation pump 80 that supplies cooling water taken from the water source to the water intake path 81 to the condenser 40, and a condenser 40. And a water discharge passage 82 for returning the cooling water used for heat exchange (steam cooling) to the water source. In this embodiment, the water source of the circulation system RL is the sea. However, depending on the location conditions of the power generation facility 1, the river may be used as the water source of the circulation system RL.

  Next, an operation method of the thermal power generation facility 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. In the following description, the case where the rated output range of the generator 30 is set to 105 MW to 320 MW and the LLO range is set to 10.5 MW to less than 105 MW is taken as an example, and the items related to the operation in the water supply system WLb. Will be explained with emphasis on.

  First, the start-up operation for starting the operation of the thermal power generation facility 1 will be described. The thermal power generation facility 1 before activation is in a disconnected state with respect to the transmission line. The thermal power generation facility 1 first drives the circulation system RL and then drives the condensate system WLa in the start-up operation for starting the operation. That is, after the circulation pump 80 is driven and the cooling water is supplied to the condenser 40, the condensate pump 53 shown in FIG. 2 is driven, and the water in the condenser 40 is sent downstream to the ejector. 56 is operated to increase the degree of vacuum in the condenser 40.

  When the degree of vacuum of the condenser 40 reaches a predetermined degree of vacuum, the water supply pump 50 is driven to supply water from the condensate system WLa to the boiler 10. If it does so, water will accumulate in the boiler 10, and the water turns into a vapor | steam, and is supplied to steam system | strain SL (1st steam pipe line SL1, bypass pipe line SL6). As a result, the steam turbines 20, 21, 22, 23 are driven to start the power generation by the generator 30, and the steam discharged from the steam turbines 20, 21, 22, 23 is sent to the condenser 40. .

  When the generator 30 starts generating power, the output of the generator 30 gradually increases, and when the output value is set in advance (for example, 10.5 MW, which is the lower limit value of the LLO region). Further, the circulation pump 80 is driven to circulate the cooling water in the circulation system RL.

  Then, when the output of the generator 30 reaches a preset output value (for example, 10.5 MW, which is the lower limit value of the LLO region), transmission of the generated power is started. Along with this, the output of the generator 30 gradually increases. Therefore, the amount of water corresponding to the output of the generator 30 (water of the condenser 40) is sent to the feed pump 50, and the condenser 40 Is made to correspond to the output (load) of the generator 30.

  On the other hand, before reaching the LLO range (10.5 MW or more to less than 105 MW), after the ignition of the boiler 10, when the pressure of the flash tank 90 becomes 0.1 or more, the heating drain valve B6 is opened and the deaerator 60 is opened. Drain water is collected. Thereafter, the pressure of the deaerator 60 is increased and the heating drain valve B6 is closed. When the pressure in the flash tank 90 becomes 0.69 MPa or more, the first steam valve B3 starts to open with an upper limit of 90%, and the first steam valve B3 causes the flash tank 90 to reach 3.5 MPa. The steam generated in the tank 90 is collected by the eighth high-pressure heater 70c. At this time, the second steam valve B4 is opened with an upper limit of 10%, and the steam is recovered to the condenser 40, though slightly.

  When the generator 30 is in a parallel state in the LLO region, ventilation is performed from the ventilation line S3 to the secondary superheater 12b of the boiler 10, and steam recovery of the steam turbines 20 to 23 is performed via the bypass line SL6. Is started. At this time, the pressure of the flash tank 90 decreases (less than 3.5 MPa), and this pressure decrease is detected by a detection means (not shown), and the ratio of the eighth high-pressure heater 70c and the condenser 40 is 9: Control to return from 1 to 7: 3. That is, as described above, the second steam valve B4 is configured to be fully closed when the pressure of the flash tank 90 is reduced, so that the second steam valve B4 is prevented from being fully closed. The ratio of the high-pressure heater 70c and the condenser 40 is returned to the original 7: 3.

  When the output of the generator 30 increases and reaches the lower limit value (105 MW) of the rated output range (105 MW or more to 320 MW or less), that is, when it is out of the LLO range (10.5 MW or more to less than 105 MW), the flash While the steam supply from the tank 90 to the boiler 10 is stopped, in the condensate system WLa, the water in the condenser 40 is supplied to the water supply pump 50 with the amount of water corresponding to the output of the generator 30. Note that the supply of steam to the bypass line SL6 is stopped before the output of the generator 30 reaches the rated output range or when the output reaches the rated output range (steam balance is adjusted). In this state, the thermal power generation facility 1 is performing a rated operation.

  On the other hand, when the stop operation for stopping thermal power generation is performed, the steam supplied from the boiler 10 to the steam turbines 20, 21, 22, and 23 is gradually reduced to lower the output of the generator 30.

  In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

  For example, in the case of the above embodiment, the ratio of the eighth high pressure heater 70c and the condenser 40 is 9: 1 before reaching the low output range, but it may be in the range of 8: 2 to 9: 1. Moreover, although the ratio at the time when the pressure drop in the flash tank 90 is detected in the low output range is set to 7: 3, it may be in the range of 7: 3 to 8: 2.

  In the case of the embodiment, the steam is recovered from the bypass line SL6 of the turbines 20 to 23 to the eighth high-pressure heater 70c of the high-pressure feed water heater 70, but has an allowable temperature lower than that of the eighth heater 70c. You may make it collect | recover to the 7th high voltage | pressure heater 70b. In addition, steam recovery pipes are connected to the sixth to eighth high-pressure heaters 70a to 70c of the high-pressure feed water heater 70 so that the steam can be recovered by the high-pressure heaters 70a to 70c according to the temperature of the steam. You may make it provide the switching means which switches each vapor | steam collection | recovery pipe line according to temperature.

  DESCRIPTION OF SYMBOLS 1 ... Thermal power generation equipment, 10 ... Boiler, 11 ... Evaporator, 12 ... Superheater, 13 ... Reheater, 20 ... High pressure turbine (steam turbine), 21 ... Medium pressure turbine (steam turbine), 22, 23 ... Low pressure Turbine (steam turbine), 30 ... generator, 40 ... condenser, 50 ... electric feed pump (feed pump), 51 ... steam-driven feed pump (feed pump), 52 ... demineralization tower, 53 ... condensate Pump, 54 condensate booster pump, 55 ... condensate heat exchanger, 56 ... ejector, 57 ... ground condenser, 58 ... drain cooler, 59 ... low pressure feed water heater, 59a-59d ... low pressure heater, 60 ... deaerator, 70 ... High-pressure feed water heater, 70a to 70c ... High-pressure heater, 80 ... Circulating pump, 81 ... Intake channel, 82 ... Discharge channel, 90 ... Flush tank, 400 ... Housing, B ... Valve, B1, B2 ... Bypass B3, B4 ... Heated steam valve, B5 ... Vent valve, B6 ... Heated drain valve, D1 ... Drain supply line, S1, S2 ... Steam supply line, S3 ... Vent line, SL1 ... First steam line, SL2 ... 2nd steam line, SL3 ... 3rd steam line, SL4 ... 4th steam line, SL5 ... 5th steam line, SL6 ... Bypass line, RL ... Circulation system, SL ... Steam system, WLa ... Condensate system, WLb ... Water supply system

Claims (2)

In a low output range where the output of the generator (30) is lower than the rated output range, together with the high pressure feed water heater (70), a flash tank (90) for raising the feed water temperature to the boiler (10), and a flash tank ( 90) and the first steam valve (B3) provided in the steam line (S1) connecting the high pressure heater (70c) of the high pressure feed water heater (70), the flash tank (90), and the condenser ( 40) in the heat recovery device of the boiler in the power generation facility provided with the second steam valve (B4) provided in the steam line (S2) connecting the
Before reaching the low output region, the valve opening of the first steam valve (B3) is set higher than the valve opening of the second steam valve (B4),
The valve opening degree of the second steam valve (B4) is controlled to be higher than the setting at the time when the low output region is reached and a pressure drop in the flash tank (90) is detected. Boiler heat recovery equipment in power generation facilities. In a low output range where the output of the generator (30) is lower than the rated output range, together with the high pressure feed water heater (70), a flash tank (90) for raising the feed water temperature to the boiler (10), and a flash tank ( 90) and the first steam valve (B3) provided in the steam line (S1) connecting the high pressure heater (70c) of the high pressure feed water heater (70), the flash tank (90), and the condenser ( 40) in the heat recovery method of the boiler in the power generation facility provided with the second steam valve (B4) provided in the steam line (S2) connecting the
Before reaching the low output range, the valve opening of the first steam valve (B3) is set higher than the valve opening of the second steam valve (B4),
In the power generation facility, wherein the valve opening degree of the second steam valve (B4) is set to be higher than the above setting when the pressure drop in the flash tank (90) is detected in the low output range. Boiler heat recovery method.

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