JP5450132B2 - Operation method of power generation equipment - Google Patents

Description

  The present invention removes impurities contained in water obtained by a steam turbine driven by steam generated in a boiler, a condenser that condenses steam that has worked in the steam turbine to condensate, and a condenser. Thermal power plant equipped with a demineralizer, a condensate pump that pumps condensate from the condenser and sends it to the demineralizer, a condensate booster pump that raises the pressure of the condensate sent from the demineralizer The present invention relates to a method for operating a power plant and other power generation facilities.

  As shown in FIG. 1, a power generation facility such as a thermal power plant basically includes a boiler 10, a steam turbine 20, a generator 30, a condenser 40, a desalting tower 50, a ground condenser 63, a low-pressure feed water heating. A device 70, a deaerator 80, a high-pressure feed water heater 90, and the like are provided. A line extending from the boiler 10, the steam turbine 20, and the condenser 40 is also referred to as a steam system A. A line extending from the condenser 40, the desalting tower 50, the ground condenser 63, the low-pressure feed water heater 70, and the deaerator 80 is also referred to as a condensate system B. A line extending from the deaerator 80, the high-pressure feed water heater 90, and the boiler 10 is also referred to as a feed water system C.

  The steam turbine 20 includes a high-pressure turbine 21, an intermediate-pressure turbine 22, a low-pressure turbine 23, and a low-pressure turbine 24 that are arranged in series, and the output shafts 25 are connected so as to be coaxial. The rotational force is transmitted to the generator 30 to operate the generator 30.

  The boiler 10 includes an evaporator 11 that evaporates water supplied from the piping of the water supply system C, a superheater 12 that superheats saturated steam evaporated by the evaporator 11, and a high-pressure turbine among the steam turbines 20. And a reheater 13 that superheats the steam from 21. The steam superheated by the superheater 12 is supplied to the high-pressure turbine 21 through the first steam line 1. Further, the steam from the high-pressure turbine 21 is supplied to the reheater 13 through the second steam line 2.

  The steam superheated by the reheater 13 is supplied to the intermediate pressure turbine 22 through the third steam line 3. Further, the intermediate pressure turbine 22 and the two low pressure turbines 23 and 24 are connected by the fourth steam line 4. Further, the two low-pressure turbines 23 and 24 and the condenser 40 are connected by the fifth steam line 5. Further, a valve 7 is attached in the middle of the first steam line 1, and the valve 7 and the condenser 40 are connected by a bypass line 6.

  The condenser 40 exchanges heat between the steam discharged from the steam turbine 20 and seawater, that is, a condenser that condenses the steam and returns it to water (condensate), and the external space and steam are introduced. A housing 41 that defines an internal space and a cooling pipe 42 that is piped inside and outside the housing 41 are provided. A water intake passage 43 and a water discharge passage 44 connected to a water source are connected to the upstream end and the downstream end of the cooling pipe 42, respectively. A circulation pump 101 for supplying cooling water to the cooling pipe 42 is attached to the intake passage 43. In addition, the line of the intake channel 43, the cooling pipe 42, and the water discharge channel 44 is also called the circulation system D.

  The desalting tower (demine) 50 removes cations and anions contained in water (condensate) with an ion exchange resin and removes impurities such as ammonia, iron, copper, and silica. In this apparatus, two towers are operated at all times, but three towers are operated when starting up (only two towers are shown). A bypass conduit 51 is arranged in parallel with the desalting tower 50, and a bypass control valve 52 is provided in the bypass conduit 51.

  The ground condenser 63 collects the seal steam (ground steam) used to seal the ground seal portion of the steam turbine 20 together with the air, heat-exchanges the mixed gas and the condensate, and supplies water ( It is a device that raises the temperature of condensate. The low-pressure feed water heater 70 is a device that heats the water fed from the condenser 40 by exchanging heat with the low-pressure steam extracted from the steam turbine 20.

  Water (condensate) from the condenser 40 is sucked by the condensate pumps 102 and 102 and sent to the demineralizer 50. In addition, condensate booster pumps 103 and 103 for increasing the pressure of water sent from the condensate pumps 102 and 102 are provided in the pipe between the desalting tower 50 and the low-pressure feed water heater 70. That is, since the pressure of water (condensate) is greatly lost by the desalting tower 50, the condensate booster pumps 103 and 103 are provided to increase the water (condensate) circulation force. Two or more condensate pumps 102, 102 and condensate booster pumps 103, 103 are provided so that the required amount can be stably fed.

  The deaerator 80 is a device that separates and removes dissolved gas in the water heated by the low-pressure feed water heater 70. A deaerator water level adjustment valve 64 for controlling the level of the deaerator 80 is provided in a pipe line between the ground condenser 63 and the low-pressure feed water heater 70.

  The high-pressure feed water heater 90 is a device that heats the water (condensate) delivered from the deaerator 80 by exchanging heat with the low-pressure steam extracted from the steam turbine 20, and the heated water Is supplied to the boiler 10. In addition, a water supply pump 104 is provided in a pipe between the deaerator 80 and the high pressure feed water heater 90, and water (condensate) from the deaerator 80 is supplied to the high pressure feed water heater 90 by the feed water pump 104. Sent out.

  The low-pressure feed water heater 70 and the high-pressure feed water heater 90 are the same type of feed water heater, but the low-pressure feed water heater 70 is located on the condenser 40 side of the feed water pump 104 with reference to the arrangement of the feed water pump 104. The boiler 10 side of the feed water pump 104 is named the high pressure feed water heater 90.

  Here, the starting operation of the above power generation equipment will be described. In the start-up operation to start the operation, first, the circulation pump 101 of the circulation system D is driven, the cooling water is supplied to the condenser 40, the condensate pumps 102 and 102 are driven, and two or more condensates A part (for example, one) of the condensate booster pumps 103 of the booster pumps 103, 103 is driven to feed water (condensate) in the condenser 40 to the downstream side.

  When the degree of vacuum of the condenser 40 is increased and reaches a predetermined degree of vacuum, the water supply pump 104 is driven to supply water (condensate) from the condensate system B to the boiler 10. Steam is generated in the boiler 10, and the steam is sent to the steam turbine 20, whereby the steam turbine 20 rotates and the generator 30 operates. The steam discharged from the steam turbine 20 is sent to the condenser 40 and cooled to become water (condensate) and circulate.

  And when the generator 30 starts electric power generation, the output of the generator 30 will increase gradually. When the output of the generator 30 reaches the lower limit value (105 MW) of the low output range lower than the rated output range, transmission of the generated power is started. Along with this, the load (output) of the generator 30 gradually increases, so that the water in the condenser 40 is directed toward the feed pump 104 with the amount of water corresponding to the output of the generator 30 in the condensate system B. The vacuum degree of the condenser 40 is made to correspond to the output (load) of the generator 30.

  Accordingly, in the condensate system B, when the output of the generator 30 goes out of the low output range lower than the rated output range (when the output value preset in the rated output range is reached), the condensate booster pumps 103 and 103 And the water in the condenser 40 is supplied to the feed pump 104 with the amount of water corresponding to the output of the generator 30, and the rated operation is performed.

  On the other hand, in the stop operation such as the start / stop mode, the steam supplied from the boiler 10 to the steam turbine 20 is gradually reduced to reduce the output of the generator 30. When the output of the generator 30 goes out of the rated output range and enters the low output range, a part of the condensate booster pump 103 is stopped, the number of the condensate booster pumps 103 is reduced, and the same number as in the start-up operation. The condensate booster pump 103 is continuously driven. When the output of the generator 30 reaches the lower limit value of the low output range, the power transmission to the transmission line is stopped (disconnected state), and the output of the generator 30 cannot be transmitted (the parallel state cannot be maintained). ) After the output becomes very small, the condensate pumps 102 and 102 are stopped.

  Therefore, in the conventional power generation facility, not only the condensate pumps 102 and 102 but also the condensate booster pumps 103 and 103 continue to operate even in the start / stop mode in order to shorten the start time. However, this makes it impossible for the conventional power generation equipment to reduce the operating cost even in the start / stop mode.

  Therefore, Patent Document 1 discloses an invention relating to a method of operating a power generation facility for solving such a problem. In this power generation facility operation method, a recirculation line (not shown) is provided between the ground condenser 63 and the condenser 40, and a recirculation valve and a bypass valve (both not shown) are provided in the recirculation line. In the start / stop mode of the steam turbine 20 in the power generation facility in which the adjustment valve is provided in the water supply line for sending water from the ground condenser 63 to the boiler 10 side. Then, the recirculation valve is opened and the bypass valve is opened, and the condensate pumps 102 and 102 are operated, while the condensate booster pumps 103 and 103 are stopped.

JP 2008-261317 A

  Generally, the power system is operated so as to maintain a predetermined rated frequency (50 Hz or 60 Hz). However, the system frequency cannot be maintained at a predetermined rated frequency when the load on the power system increases temporarily or when a load interruption occurs. In such a case, an automatic frequency control (AFC) signal is output from the power supply command device, and the system frequency is set to a predetermined rated frequency by controlling the output of the generator 30 based on the load command signal and the automatic frequency control signal. To be maintained.

  The water of the condensate system B is circulated by the condensate pumps 102 and 102 and the condensate booster pumps 103 and 103. For example, during rated load operation, which is the upper limit (320 MW) of the rated output range, and when an AFC signal is output, the two condensate pumps 102 and 102 and the two condensate booster pumps 103 and 103 are driven. During the minimum load operation, which is the lower limit (105 MW) of the low output range, and when another AFC signal is output, one condensate pump 102 and one condensate booster pump 103, 103 are driven. .

  In the condensate system B, all the water in the condenser 40 sucked by the condensate pumps 102 and 102 is sent to the desalting tower 50 at the time of startup, and impurities are removed by the desalting tower 50. Water is sent out toward the low-pressure feed water heater 70 by the condensate booster pumps 103 and 103. However, after 12 hours have passed since the start, it has been confirmed from experience that the water sucked from the condenser 40 contains almost no impurities (slightly contains). After a lapse of time, about 1/4 of the water flows through the desalting tower 50, and about 3/4 of the water passes through the bypass line 51 provided with the bypass control valve 52 and is sent to the low-pressure feed water heater 70 ( 1/4 water flow). Thus, the water quality of the water discharged | emitted from the demineralization tower 50 at the time of normal driving | operation can be ensured by passing 1/4 water.

  In order to allow about 3/4 of the water to flow through the bypass line 51, the bypass regulating valve 52 is 75% open. During the minimum load operation, since the load decreases, the deaerator water level adjustment valve 64 is automatically throttled to 18%, and the flow rate of water sent to the low-pressure feed water heater 70 is reduced.

  However, some of the conventional power generation facilities, including those described in Patent Document 1, flow only in 1/4 of the water in the desalting tower 50 and the pressure loss is reduced. The condensate booster pump 103 is driven. That is, the condensate booster pumps 103 and 103 are driven even when they are not necessary. In order to drive the condensate booster pumps 103, 103, power is consumed, so that conventional power generation facilities lose energy in vain.

  Accordingly, an object of the present invention is to provide a method for operating a power generation facility in which the condensate booster pump is driven only when necessary and is not driven when unnecessary.

An operation method of a power generation facility according to the present invention includes a boiler that generates steam to be supplied to a steam turbine, a condenser that drives a generator and returns steam discharged from the steam turbine to water, and the condenser A desalting tower for removing impurities contained in the obtained water, a condensate pump for sending water in the condenser to the desalting tower, and boosting the water in the desalting tower to the boiler a condensate booster pump, in parallel to the demineralizer between a condensate pump and the condensate booster pump, and a calling generation facilities method operation and a bypass line provided with a bypass regulating valve When the impurities contained in the water decrease , the opening of the bypass control valve is increased so that the water discharged from the condenser flows through the desalting tower and the bypass pipe, and the number of condensate booster pumps driven is increased. It is characterized by reducing or stopping and circulating the water.

  During the start-up operation of this power generation facility, the bypass control valve is closed and all the water sent from the condenser is sent to the desalting tower, and impurities in the water are gradually removed. When it becomes unnecessary to remove impurities contained in the desalting tower, the opening of the bypass control valve is increased. By doing so, while reducing the flow volume of the water sent from a condenser to a de-emission tower, it is set as the state which increased the amount of water flow to a bypass line. By reducing the amount of water passing through the deeerator tower, the amount of water whose pressure is reduced by the deeerator tower is reduced, so that the water can be circulated even if the number of driven condensate booster pumps is reduced or stopped.

  And the energy (electric power) for driving a condensate pressure | voltage rise pump can be saved by reducing or stopping the drive number of condensate pressure | voltage rise pumps. Since water passing through the desalting tower is reduced, maintenance such as replacement of an ion exchange resin provided in the desalting tower can be reduced.

  In the operation method of the power generation facility according to the present invention, it is preferable that the condensate booster pump is stopped and water is circulated only by the condensate pump during the minimum load operation. In this power generation facility, the amount of water to be circulated is reduced during the minimum load operation compared to the rated load operation, so even when multiple condensate booster pumps are provided, all the condensate booster pumps are stopped. However, water can be circulated simply by driving the condensate pump.

  Further, in the operation method of the power generation facility according to the present invention, the condensate booster pump may be stopped by the automatic frequency control signal, and the water may be circulated only by the condensate pump. According to the operation method of the power generation facility, even when the amount of water to be sent is reduced by the automatic frequency control signal compared to the rated load operation, the condensate booster pump is stopped and the condensate pump is turned off. Water can be circulated only by driving.

  According to the present invention, it is not necessary to remove impurities contained in water by a desalting tower, and the number of condensate booster pumps is reduced or stopped at the time of minimum load operation, and water is circulated only by the condensate pump. By doing so, it is possible to provide a method of operating a power generation facility that can save energy (electric power) for driving the condensate booster pump.

It is the whole conceptual diagram explaining the operating method of the power generation equipment which concerns on this invention. It is a conceptual diagram of the principal part explaining the operating method of the power generation equipment which concerns on this invention.

  An embodiment of a method for operating a power generation facility according to the present invention will be described with reference to FIGS. 1 and 2. In addition, about the apparatus demonstrated in background art, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The operation method of the power generation facility of this embodiment is implemented by the power generation facility described in the background art, and the main part will be described in detail with reference to FIG. This power generation facility includes a condensate heat exchanger 61, an ejector 62, a ground condenser 63 as described above, and a ground condenser 63 as described above between the condensate boost pumps 103 and 103 and the low-pressure feed water heater 70 in the condensate system B. A deaerator water level control valve 64 and a drain cooler 65 are provided.

  The condensate heat exchanger 61 is a device that increases the temperature of the condensate by exchanging heat between the condensate and water used as bearing cooling water for the steam turbine 20. The ejector 62 is an apparatus for extracting air from the condensate by a jet action by a steam jet and maintaining the vacuum state of the condenser 40. The drain cooler 65 is a device for causing the drain and condensate generated by cooling the turbine bleed air in the low-pressure feed water heater 70 to exchange heat to increase the temperature of the condensate and cool the drain. .

  Since the other apparatus in the power generation facility has been described with reference to FIG. 1 in the background art, the operation method of the power generation facility of the present invention will be described next.

  In the start-up operation for starting the operation, the circulation pump 101 of the circulation system D is driven, the cooling water is supplied to the condenser 40, the condensate pumps 102 and 102 are driven, and two or more condensate boost pumps are driven. A part (for example, one) of the condensate booster pumps 103 is driven, and the water in the condenser 40 is sent to the downstream side.

  Further, the ejector 62 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 104 is driven to supply water from the condensate system B to the boiler 10. Then, water accumulates in the boiler 10, the water becomes steam, this steam is supplied to the steam turbine 20, and the rotational force from the output shaft of the steam turbine 20 is transmitted to the generator 30, thereby generating the generator 30. Operates.

  The output of the generator 30 gradually increases, and when the output reaches a preset output value, power transmission is started. When the output of the generator 30 reaches the lower limit value (105 MW) of the rated output range, the number of the condensate booster pumps 103 and 103 is increased, and the amount of water corresponding to the output of the generator 30 is increased. Is supplied to the feed water pump 104. Until 12 hours have passed since the start, the bypass control valve 52 is completely closed, and the water sent from the two condensate pumps 102, 102 does not flow through the bypass pipe 51, Impurities contained in the water (condensate) are removed through the desalting tower 50.

  Further, it has been confirmed from experience that impurities contained in water (condensate) are almost not contained after 12 hours have passed since the start (actually before 12 hours have passed). Therefore, the bypass control valve 52 is opened about 75%, and about 1/4 of the water sent from the condenser 40 is sent to the demineralizer 50 to remove the remaining impurities, and about 3/4. Is sent to the bypass line 51.

  And in order to generate the electric energy according to power transmission, the output of the generator 30 fluctuates within the rated output range (105 MW or more and 320 MW or less), but at the rated load (320 MW), the two condensate pumps 102, 102 and two condensate booster pumps 103 and 103 are driven. Further, the two condensate pumps 102 and 102 and the two condensate booster pumps 103 and 103 are driven by the AFC signal.

When the power demand decreases, such as at midnight, the output of the generator 30 is reduced, but at the time of the minimum load (105 MW) operation, the amount of water (condensate) supplied to the boiler 10 is reduced and the deaerator water level control valve 64 is reduced. Is reduced to 18%, for example. Since the amount of water (condensate) decreases, and only about 1/4 of the water from the condenser 40 (condensate) is sent to the desalting tower 50, the water is removed by the desalting tower 50. (Condensate) pressure is not lost greatly. Further, the deaerator water level adjustment Fushiben 64 is 60-70% of the opening. In this way, during the minimum load operation, only one condensate pump 102 is driven, the condensate booster pumps 103 and 103 are stopped, and water (condensate) is circulated. Incidentally, condensate booster pumps 103, 103, the opening degree of the deaerator water level adjustment Fushiben 64 is small, is stopped when the opening degree of the bypass regulating valve 52 is large.

  Then, when the condensate booster pumps 103 and 103 are stopped, the power for driving the condensate pumps 102 and 102 can be reduced. In addition, since the water passing through the desalting tower 50 is reduced, it is possible to reduce maintenance such as replacement of an ion exchange resin provided in the desalting tower 50.

  In addition, this invention can be variously changed without being limited to the said embodiment. For example, in a power generation facility provided with three or more condensate booster pumps 103, only one condensate booster pump 103 is stopped at the time of the minimum load operation, that is, the number of the condensate booster pumps 103 driven is reduced. You may do it.

  When the deaerator water level control valve 64 is throttled to 18% by the automatic frequency control signal, the condensate booster pumps 103 and 103 are stopped by the automatic frequency control signal, and only the condensate pumps 102 and 102 are stopped. You may circulate water.

  The power generation facility shown in the figure is an example. If the condensate pumps 102 and 102, the condensate booster pumps 103 and 103, and the bypass control valve 52 are provided, the power generation facility is also implemented in other power generation facilities including various devices. can do. Furthermore, the present invention can be implemented not only in thermal power plants but also in nuclear power plants.

10 ......... Boiler 20 ......... Steam turbine 30 ......... Generator 40 ......... Condenser 50 ......... Desalination tower 51 ......... Bypass conduit 52 ...... Bypass control valve 102 ... Condensate Pump 103 ... Condensate booster pump

Claims (3)

A boiler that generates steam to be supplied to the steam turbine, a condenser that drives the generator to return the steam discharged from the steam turbine to water, and removes impurities contained in the water obtained by the condenser A demineralizer, a condensate pump that sends water in the condenser to the demineralizer, a condensate booster pump that boosts the water in the demineralizer and sends it to the boiler, a condensate pump and a condensate pump in parallel to the demineralizer between water booster pump, and a calling generation facilities method operation and a bypass line provided with a bypass control valve,
When impurities contained in the water decrease , the opening of the bypass control valve is increased so that the water discharged from the condenser flows through the desalting tower and the bypass pipe, and the number of condensing booster pumps driven is reduced. A method of operating a power generation facility characterized in that water is circulated after stopping.   The operation method of the power generation facility according to claim 1, wherein the condensate booster pump is stopped and water is circulated only by the condensate pump during the minimum load operation.   2. The method of operating a power generation facility according to claim 1, wherein the condensate booster pump is stopped by an automatic frequency control signal, and water is circulated only by the condensate pump.

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