JP2006226697A - Cooling controller, cooling control method and plant using cooling controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the flow rate of cooling water capable of keeping the temperature of the cooling water within a safe range and sufficiently cooling blowdown water. <P>SOLUTION: When the temperature of the blowdown water cooled by heat exchangers 17, 18 is detected by a first temperature detector 25, the opening of a first flow rate control valve unit 26 is controlled to regulate the temperature of the blowdown water within a tolerance. When the temperature of cooling water discharged to a discharge line 24 in the heat exchangers 17, 18 is detected by a second temperature detector 28, the opening of a second flow rate control valve unit 29 is controlled to regulate the temperature of the cooling water within a tolerance. Thus, the flow rate of the cooling water flowing through the heat exchangers 17, 18 is controlled. By employing such a flow rate control, the temperature of the cooling water and the blowdown water can be regulated between the upper and the lower limits. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling control apparatus, a cooling control method, and a plant using the cooling control apparatus for cooling a part of liquid to be converted into steam for driving a fluid machine, and a liquid whose temperature is limited. The present invention relates to a cooling control device for cooling, a cooling control method, and a plant using the cooling control device.

  Conventionally, as shown in FIG. 7, a nuclear power plant heats primary water by heat generated in a nuclear reactor 1 and introduces the heated primary water into a steam generator 2 to form a secondary. Change system water to steam. The steam turbine 3 is rotationally driven by the steam obtained from the secondary water to operate the generator 3a to generate power. Then, the steam discharged from the steam turbine 3 after rotating the steam turbine 3 is cooled by seawater in the condenser 4 to be condensed and supplied to the steam generator 2. At this time, a condensate demineralizer 7 is provided in order to remove impurities from the water condensed in the condenser 4. In this condensate demineralizer 7, impurities are removed by ion exchange of water from the condenser 4. In order to prevent impurities from accumulating and concentrating in the steam generator 2, a part of the secondary water is blown down and discharged from the steam generator 2 to the discharge system 15. The blown-down secondary water is collected in the condensate system 5 (see Patent Document 1).

  The condensate system 5 in which the secondary water condensed by the condenser 4 is supplied to the steam generator 2 is provided with a bypass 12 for bypassing the condensate demineralizer 7. Yes. By providing this bypass path 12, in order to prevent elution of iron components and the like in the equipment piping, when ammonia is introduced into the secondary water circulation system and operated at a high pH, in the condensate demineralizer 7 A situation where unnecessary chemicals are removed can be prevented. That is, at the time of high pH, the first valve device 13 is closed and the second valve device 14 is opened, so that the water flow from the condenser 4 to the condensate demineralizer 7 is eliminated, and at the time of starting, etc. When the ammonia concentration of the secondary water is low, water is passed from the condenser 4 to the condensate demineralizer 7 by opening the first valve device 13 and closing the second valve device 14. At this time, the water in the condenser 4 is supplied to the condensate demineralizer 7 or the bypass 12 by the condensate pump 6.

  The secondary water blown down from the steam generator 2 is collected in the condensate system 5. At this time, the water between the steam generator 2, the first valve device 13 and the condensate demineralizer 7 is used. A discharge system 15 is formed between the condensate system 5 and a part of the secondary water blown down is input to the condensate system 5 by the discharge system 15. The discharge system 15 includes a flash tank 21 into which a part of secondary water blown down from the steam generator 2 is introduced, and a mist separator that separates the steam in the flash tank 21 and sends it to the deaerator 10. 22 and a cooling unit 16 by heat exchangers 17 and 18 for cooling water returned to the flash tank 21 after the vapor is separated by the mist separator 22.

In the heat exchangers 17 and 18, secondary water from a condenser branched by an extraction line 20 provided downstream of the condensate demineralizer 7 and the bypass 12 is supplied with a cooling medium (hereinafter referred to as this medium). Secondary water serving as a cooling medium is referred to as “cooling water” and is supplied as secondary water from the flash tank 21 that passes through the heat exchangers 17 and 18 (hereinafter referred to as “cooling water”). The secondary water is called “blowdown water”). The blowdown water cooled by the heat exchangers 17 and 18 in this way is supplied to the condensate demineralizer 7. The secondary water from the condensate demineralizer 7 and the bypass 12 is supplied to the low-pressure feed water heater 9 by the condensate booster pump 8 and heated, and is branched by the extraction line 20 and heated. In the exchangers 17 and 18, the cooling water heated by the blowdown water from the flash tank 21 is merged and supplied to the deaerator 10.
JP 2001-296389 A

  In such a power plant, it is necessary to cool the high-temperature blowdown water from the flash tank 21 to the allowable temperature of the condensate demineralizer 7 with the heat exchangers 17 and 18. Therefore, conventionally, the heat exchangers 17 and 18 are extracted from the extraction line 20 so that the temperature of the blowdown water discharged from the heat exchanger 18 becomes constant at the allowable temperature of the condensate demineralizer 7 of about 40 degrees. The flow rate of the cooling water supplied to is controlled. At this time, when the flow rate from the flash tank 21 decreases or when the water temperature in the condenser 4 decreases, the temperature of the blow-down water discharged from the heat exchanger 18 decreases. And since the control which maintains the temperature of the blowdown water discharged | emitted from the heat exchanger 18 is performed constant, the flow volume of the cooling water which flows into the heat exchangers 17 and 18 via the extraction line 20 is decreased.

  As a result of reducing the flow rate of the cooling water supplied to the heat exchangers 17 and 18 as described above, the temperature of the cooling water discharged from the heat exchanger 17 increases. That is, when the flow rate from the flash tank 21 decreases, the temperature of the cooling water discharged from the heat exchanger 17 increases, and when the water temperature in the condenser 4 decreases, similarly, the cooling water is discharged from the heat exchanger 17. The temperature of the cooling water is increased. And if the temperature of the cooling water discharged from the heat exchanger 17 becomes too high, a flash is generated, and after joining at the downstream side of the low-pressure feed water heater 9, a water hammer phenomenon is generated and the piping is damaged. give. Moreover, if the temperature of the cooling water discharged | emitted from the heat exchanger 17 falls, the whole load of a power plant will fall. At this time, if the overall load of the power plant is reduced, the upper limit of the temperature of the cooling water discharged from the heat exchanger 17 for avoiding the flash is further lowered, so that the flash is more likely to occur.

  In view of such problems, the present invention provides a cooling control device and a cooling control for controlling the cooling water flow rate so that the temperature of the cooling water can be maintained within a safe range and sufficient cooling operation can be performed. It aims to provide a method. The present invention also provides a plant including a cooling control device that controls the flow rate of cooling water so that the temperature of the cooling water can be maintained within a safe range and sufficient cooling operation can be performed. Another purpose.

  In order to achieve the above object, a cooling control device of the present invention comprises a heat exchanger that cools a part of a liquid blown down and discharged from a steam generator that heats the liquid and generates high-temperature steam; Cooling medium extraction that branches the liquid condensed in the condenser from a liquid supply path that supplies the steam generator, and supplies a part of the liquid that passes through the liquid supply path to the heat exchanger as a cooling medium. A bypass that connects the passage, a cooling medium discharge path that joins the liquid used as a cooling medium that has worked in the heat exchanger to the liquid supply path, and the cooling medium extraction path and the cooling medium discharge path A first temperature detector for measuring the temperature of the liquid cooled by the heat exchanger, and the temperature of the liquid used as the cooling medium and discharged from the heat exchanger to the cooling medium discharge path. A second temperature detector to be measured; In the cooling control device including a first flow rate control valve for determining a flow rate of the liquid flowing through the medium discharge path and a second flow rate control valve for determining a flow rate of the liquid flowing through the bypass path, the first temperature detection unit The opening degree of the first flow rate control valve and the second flow rate control valve is set based on the detected temperature of the liquid used as the cooling medium and the temperature of the liquid detected by the second temperature detection unit. And a flow rate control unit that controls the flow rate of the liquid used as the cooling medium supplied to the heat exchanger.

  In such a cooling control device, the position where the bypass passage joins the cooling medium discharge passage may be on the upstream side or the downstream side of the first flow control valve.

  In such a cooling control device, when the temperature of the liquid cooled by the heat exchanger measured by the first temperature detection unit becomes higher than a first allowable upper limit value, the opening degree of the first flow control valve The flow rate of the liquid used as the cooling medium supplied to the heat exchanger is increased, and the temperature of the liquid cooled by the heat exchanger measured by the first temperature detection unit is allowed. When it becomes lower than the lower limit, the opening of the first flow rate control valve is narrowed to reduce the flow rate of the liquid used as the cooling medium supplied to the heat exchanger. Thus, the liquid cooled by the heat exchanger is controlled by controlling the flow rate of the liquid serving as the cooling medium so that the temperature of the liquid serving as the cooling medium discharged from the exchanger falls within an allowable range. The temperature can be within an allowable range.

  The liquid cooled by the heat exchanger is supplied to a desalting apparatus that removes impurities from the liquid, and the first allowable upper limit value is a value set for the desalting apparatus. Since the temperature of the liquid cooled in the heat exchanger is controlled to be between the first allowable upper limit value and the first allowable lower limit value, the liquid flowing out of the heat exchanger is directly supplied to the desalination apparatus. Can be supplied.

  Further, when it is confirmed that the temperature of the liquid used as the cooling medium measured by the second temperature detection unit exceeds the second allowable upper limit value, the opening degree of the second flow rate control valve is increased. The temperature of the liquid used as the cooling medium measured by the second temperature detection unit while increasing the flow rate of the liquid that branches and flows into the bypass path among the liquid flowing through the cooling medium extraction path Is lower than the second allowable lower limit, the opening of the second flow rate control valve is narrowed to reduce the flow rate of the liquid that flows into the bypass path out of the liquid flowing through the cooling medium extraction path. To do. The liquid used as the cooling medium discharged to the cooling medium discharge path is heated by the heat exchanger to be a high temperature, and a part of the low-temperature liquid flowing through the cooling medium extraction path is The temperature of the liquid flowing in the cooling medium discharge path can be lowered by flowing the bypass path and joining the high-temperature liquid.

  Thus, since the temperature of the liquid flowing through the cooling medium discharge path is controlled to be between the second allowable upper limit value and the second allowable lower limit value, the liquid from the cooling medium discharge path merges, Since the temperature of the liquid in the liquid supply path is increased, the temperature of the liquid supplied to the steam generator can be increased, and energy efficiency can be improved accordingly. Further, by preventing the temperature of the liquid flowing through the cooling medium discharge path from rising excessively, the liquid used as the cooling medium flowing through the cooling medium discharge path is flushed when joining the liquid supply path. And water hammer can be prevented.

  And a second heat exchanger that cools the liquid discharged from the heat exchanger using a liquid that is used as a cooling medium supplied from another system, the opening of the first flow control valve being fully open. When the temperature measured by the first temperature detection unit exceeds the first allowable upper limit value, the flow rate of the liquid used as the cooling medium from the separate system supplied to the second heat exchanger is increased. Thus, the temperature measured by the first temperature detection unit may be lower than the first allowable upper limit value. At this time, it includes a third temperature detection unit that measures the temperature of the liquid discharged from the second heat exchanger, and when the temperature measured by the third temperature detection unit exceeds a third allowable upper limit value, Increasing the flow rate of the liquid serving as a cooling medium from the separate system supplied to the second heat exchanger so that the temperature measured by the third temperature detection unit is lower than the third allowable upper limit value. It doesn't matter.

  Further, the cooling control method of the present invention cools a part of the liquid blown down from a steam generator that heats the liquid and generates high-temperature steam, and condenses the steam with a condenser. The liquid used is passed through a liquid supply path for supplying the vapor generator, a part of the liquid is supplied as a cooling medium to the heat exchanger, and used as a cooling medium that performs work in the heat exchanger. A cooling control method for joining a liquid to the liquid supply path, the first step of measuring the temperature of the liquid cooled by the heat exchanger, and used as the cooling medium discharged from the heat exchanger A second step of measuring the temperature of the liquid, and a liquid used as the cooling medium supplied to the heat exchanger based on the temperature of the liquid cooled by the heat exchanger detected in the first step. To determine the flow rate Use as the cooling medium supplied to the heat exchanger based on the third step of setting the opening of the flow control valve and the temperature of the liquid used as the cooling medium detected in the second step A fourth step of setting an opening degree of a second flow rate control valve provided in a bypass for joining a part of the liquid to be used with the liquid used as the cooling medium discharged from the heat exchanger; It is characterized by providing.

  At this time, when the temperature of the liquid cooled by the heat exchanger measured in the first step becomes higher than a first allowable upper limit value, the opening degree of the first flow rate control valve is increased, and the heat exchange is performed. When the flow rate of the liquid used as the cooling medium supplied to the vessel is increased and the temperature of the liquid serving as the cooling medium measured in the first step is lower than a first allowable lower limit value, 1 The flow rate of the liquid serving as the cooling medium supplied to the heat exchanger is reduced by narrowing the opening of the flow rate control valve.

  Further, when the temperature of the liquid used as the cooling medium measured in the second step becomes higher than a second allowable upper limit value, the opening of the second flow rate control valve is widened, and the cooling medium extraction path Among the liquids used as the cooling medium flowing through the flow path, the flow rate of the liquid branched and flowing into the bypass path is increased, and the temperature of the liquid serving as the cooling medium measured in the second step is a second allowable value. When the pressure is lower than the lower limit value, the opening of the first flow control valve is narrowed, and the liquid that flows into the bypass path out of the liquid that is used as the cooling medium flowing through the cooling medium extraction path. Reduce the flow rate.

  The plant of the present invention includes a steam generator that heats a liquid to generate high-temperature steam, a condenser that condenses the steam generated by the steam generator into a liquid, and the condenser that has been condensed by the condenser. A liquid supply path for supplying liquid to the steam generator, a heat exchanger for cooling a part of the liquid drained from the steam generator, and a liquid passing through the liquid supply path to the heat exchanger. A cooling medium extraction path for supplying a part as a cooling medium, a cooling medium discharge path for merging the liquid as a cooling medium that has performed work in the heat exchanger to the liquid supply path, the cooling medium extraction path, and the cooling In a plant comprising a bypass path connecting a medium discharge path, a first temperature detection unit that measures the temperature of the liquid cooled by the heat exchanger, and used as the cooling medium, from the heat exchanger The temperature of the liquid discharged to the cooling medium discharge path A second temperature detector for measuring, a first flow control valve for determining a flow rate of the liquid flowing through the cooling medium discharge path, a second flow control valve for determining a flow rate of the liquid flowing through the bypass path, and the first The first flow rate control based on the temperature of the liquid cooled by the heat exchanger detected by the temperature detector and the temperature of the liquid used as the cooling medium detected by the second temperature detector. And a flow rate controller configured to set a degree of opening of the valve and the second flow rate control valve and to control a flow rate of the liquid used as the cooling medium supplied to the heat exchanger.

  At this time, when the temperature of the liquid cooled by the heat exchanger measured by the first temperature detection unit is higher than a first allowable upper limit value, the opening of the first flow control valve is expanded, While increasing the flow rate of the liquid used as the cooling medium supplied to the heat exchanger, the temperature of the liquid cooled by the heat exchanger measured by the first temperature detection unit becomes lower than the allowable lower limit value. Then, the opening of the first flow control valve is narrowed to reduce the flow rate of the liquid used as the cooling medium supplied to the heat exchanger.

  Further, when the temperature of the liquid used as the cooling medium measured by the second temperature detection unit becomes higher than a second allowable upper limit value, the opening degree of the second flow rate control valve is increased, and the cooling medium is increased. Among the liquids used as the cooling medium flowing in the extraction path, the liquid used as the cooling medium measured by the second temperature detection unit is increased while increasing the flow rate of the liquid that branches and flows into the bypass path. When the temperature of the liquid becomes lower than the second allowable lower limit value, the opening of the second flow rate control valve is narrowed, and the liquid used as the cooling medium flowing in the cooling medium extraction path branches to the bypass path The flow rate of the flowing liquid is reduced.

  Further, a desalting apparatus for removing impurities from the liquid cooled by the heat exchanger may be provided. At this time, the first allowable upper limit value is for the desalting apparatus.

  According to the present invention, the flow rate of the liquid serving as the cooling medium is controlled based on the temperature of the liquid serving as the cooling medium discharged from the heat exchanger to the liquid supply path. The liquid cooled by the heat exchanger can be stored below the allowable upper limit temperature. As described above, it is possible to provide a sufficient cooling effect with the heat exchanger, and it is possible to prevent the flash from being generated in the liquid supply path due to the liquid serving as the cooling medium discharged from the heat exchanger. In addition, by maintaining the temperature of the liquid serving as the cooling medium within an allowable range, when the plant is a power plant, the temperature of the liquid serving as the cooling medium can be prevented from decreasing, and the decrease in the overall load on the plant is suppressed. can do.

<First Embodiment>
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a power plant in the present embodiment. In the power plant of FIG. 1, the same parts as those in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The power plant shown in FIG. 1 includes a nuclear reactor 1 that heats primary water by fission thermal energy, and steam that introduces water heated in the nuclear reactor 1 and heats secondary water to generate steam. A generator 2, a steam turbine 3 that is rotationally driven by steam generated by the steam generator 2, a generator 3 a that performs a power generation operation by rotation of the steam turbine 3, and a steam turbine 3 that is used for rotationally driving the steam turbine 3. A condenser 4 that condenses the discharged steam with seawater, a condensate system 5 that supplies secondary water condensed by the condenser 4 to the steam generator 2, and a steam generator 2 And a discharge system 15 for discharging a part of the secondary water blown down to the condensate system 5.

  The condensate system 5 includes a condensate pump 6 that supplies secondary water condensed by the condenser 4 to the condensate system 5, and a secondary water or discharge system from the condenser 4. 15, a condensate demineralizer 7 that removes impurities from the blowdown water merged from 15, a bypass 12 that bypasses the condensate demineralizer 7 with respect to secondary water from the condenser 4, and condensate A condensate booster pump 8 that allows secondary water from the desalinator 7 and the bypass 12 to flow downstream, and a low-pressure feed water heater 9 that heats the secondary water supplied by the condensate booster pump 8. And a deaerator 10 for further heating the secondary water heated by the low-pressure feed water heater 9 with the steam separated by the mist separator 22 and supplying it to the steam generator 2, and the condensate pump 6. A first valve device 13 that controls the flow of secondary water to the condensate demineralizer 7 and the condensate pump 6. Includes a second valve device 14 for controlling the water flow to the bypass passage 12 of the sheet is the secondary system water.

  The discharge system 15 separates the vapor from the flash tank 21 from which the secondary water blown down by the steam generator 2 is discharged and the secondary water blown down to the flash tank 21 to remove the water. A mist separator 22 discharged to the air vessel 10, heat exchangers 17 and 18 for cooling secondary water (blow-down water) discharged from the flash tank 21, and a blow cooled by the heat exchangers 17 and 18 And a supply pump 23 for supplying down water to the condensate system 5. Thus, when the discharge system 15 is comprised, the extraction line 20 used as a tributary is provided between the condensate booster pump 8 and the low-pressure feed water heater 9 of the condensate system 5, and water passes through the condensate system 5. Secondary water is supplied to the heat exchanger 18 as cooling water from the extraction line 20. A first temperature measuring device 25 for measuring the temperature of water (blow-down water) cooled by the heat exchanger is installed downstream of the heat exchanger 18 of the discharge system 15.

  Further, the heat exchanger 17 is connected to a discharge line 24 where the cooling water discharged from the heat exchanger 17 is joined with the secondary water of the condensate system 5 between the low-pressure feed water heater 9 and the deaerator 10. A second temperature detector 28 that measures the temperature of the cooling water discharged to the discharge line 24 and a first flow rate control valve device 26 that determines the flow rate of the cooling water flowing through the extraction line 20 and the discharge line 24 are installed. The Further, a cooling water bypass line 27 that connects the extraction line 20 and the discharge line 24 and a cooling water bypass line 27 branch from the extraction line 20 and determine the flow rate of the cooling water that flows through the cooling water bypass line 27. A two-flow control valve device 29 is installed.

  Thus, when the first temperature detector 25, the second temperature detector 28, the first flow rate control valve device 26, and the second flow rate control valve device 29 are installed, the flow rate control device 30 causes the first temperature detector to be set. Based on the temperature of the blow-down water cooled by the heat exchangers 17 and 18 detected at 25, the opening degree of the first flow control valve device 26 is determined, and the cooling water flowing through the extraction line 20 and the discharge line 24, respectively. Is controlled in flow rate. Further, the opening degree of the second flow control valve device 29 is determined based on the temperature of the cooling water discharged from the heat exchanger 17 detected by the second temperature detector 28, and flows through the cooling water bypass line 27. The flow rate of the low-temperature cooling water branched from the extraction line 20 is determined. The first temperature detector 25, the first flow rate control valve device 26, the second temperature detector 28, the second flow rate control valve device 29 and the flow rate control device 30, and the heat exchangers 17 and 18, the cooling control device 31. Is formed.

  Operation | movement of the cooling control apparatus 31 in the power plant comprised in this way is demonstrated below. Blowdown water of approximately 207 degrees discharged from the flash tank 21 is supplied to the heat exchangers 17 and 18 branched from the condensate system 5 by the extraction line 20 by passing the heat exchangers 17 and 18. The water is exchanged with the cooling water, cooled, and supplied to the condensate demineralizer 7. Thus, the temperature of the blow-down water cooled by the heat exchangers 17 and 18 is set to an allowable upper limit temperature (for example, 40 degrees) or less for supplying to the condensate demineralizer 7. In addition, the cooling water that has passed through the heat exchangers 17 and 18 is heated in order to exchange heat with the hot blowdown water from the flash tank 21. Then, when the heated cooling water is discharged from the heat exchanger 17, it is joined to the secondary water of the condensate system 5 through the discharge line 24.

  At this time, when the temperature of the blowdown water cooled by the heat exchangers 17 and 18 is measured by the first temperature detector 25, the measured temperature information is given to the flow control device 30. And in the flow control apparatus 30, the 1st flow control valve apparatus 26 is based on the temperature information from the 1st temperature detector 25 so that the temperature of the blowdown water cooled with the heat exchangers 17 and 18 may become fixed. And the flow rate of the cooling water flowing through the extraction line 20, the discharge line 24, and the heat exchangers 17 and 18 is controlled. Further, when the temperature of the cooling water discharged from the heat exchanger 17 to the discharge line 24 is measured by the second temperature detector 28, the measured temperature information is given to the flow rate control device 30. The flow control device 30 sets the opening of the second flow control valve device 29 based on the temperature information from the second temperature detector 28, branches from the extraction line 20, and flows through the cooling water bypass line 27. The flow rate of the cooling water that merges with the cooling water flowing through the discharge line 24 is controlled. The control operation in the flow control device 30 will be described with reference to the flowchart of FIG.

  Temperature information is acquired from a first temperature detector 25 that is installed in the discharge system 15 and is cooled by the heat exchangers 17 and 18 and measures the temperature of the blowdown water (STEP 1). The temperature T of the blowdown water discharged from the heat exchanger 18 measured by the detector 25 is confirmed. Then, the confirmed temperature T of the blowdown water is compared with the upper limit value T1 of the allowable range of the temperature of the blowdown water cooled by the heat exchangers 17 and 18 (STEP 2). Then, when it is confirmed that the temperature T of the blowdown water is higher than the upper limit value T1 (YES), a control operation for expanding the opening of the first flow control valve device 26 is performed (STEP 3). At this time, the opening degree of the first flow control valve device 26 may be increased by a predetermined amount, and the first flow control valve device 26 is controlled based on the temperature difference between the temperature T of the blowdown water and the upper limit value T1. The opening degree may be set.

  If it is confirmed in STEP 2 that the temperature T of the blowdown water is equal to or lower than the upper limit value T1 (NO), then the temperature T of the cooling water is changed to the temperature of the blowdown water discharged from the heat exchanger 18. Is compared with a lower limit value T2 (T2 <T1) of the allowable range (STEP 4). When it is confirmed that the temperature T of the blowdown water is lower than the lower limit value T2 (YES), a control operation for narrowing the opening degree of the first flow control valve device 26 is performed (STEP 5). At this time, the opening degree of the first flow control valve device 26 may be narrowed by a predetermined value, and the first flow control valve device 26 is controlled based on the temperature difference between the temperature T of the blowdown water and the lower limit value T2. The opening degree may be set.

  After setting the opening of the first flow control valve device 26 in STEP 3 or STEP 5 or after confirming that the temperature T of the blowdown water is equal to or higher than the lower limit value T2 in STEP 4 (NO), from the heat exchanger 17 Temperature information is acquired from the second temperature detector 28 that measures the temperature of the cooling water discharged to the discharge line 24 (STEP 6), and the discharge line 24 measured by the second temperature detector 28 based on this temperature information. Check the temperature t of the cooling water. And the temperature of the cooling water which flows through the confirmed discharge line 24 is compared with the upper limit t1 of the allowable range of the temperature of the cooling water discharged from the heat exchanger 17 (STEP 7). When it is confirmed that the temperature t of the cooling water is higher than the upper limit value t1 (YES), a control operation for expanding the opening of the second flow control valve device 29 is performed (STEP 8). At this time, the opening degree of the second flow rate control valve device 29 may be increased by a predetermined amount, and the opening of the second flow rate control valve device 29 is based on the temperature difference between the temperature t of the cooling water and the upper limit value t1. You may make it set a degree.

  Further, if it is confirmed in STEP 7 that the temperature of the cooling water is equal to or lower than the upper limit value t1 (NO), then, the temperature t of the cooling water is changed to an allowable range of the temperature of the cooling water discharged from the heat exchanger 17. Is compared with a lower limit value t2 (t2 <t1) (STEP 9). When it is confirmed that the temperature t of the cooling water is lower than the lower limit value t2 (YES), a control operation for narrowing the opening degree of the second flow control valve device 29 is performed (STEP 10). At this time, the opening of the second flow control valve device 29 may be narrowed by a predetermined amount, and the opening of the second flow control valve device 29 is based on the temperature difference between the temperature t of the cooling water and the upper limit value t1. You may make it set a degree.

  After setting the opening of the second flow control valve device 29 in STEP 8 or STEP 10, or after confirming that the temperature t of the cooling water is equal to or higher than the lower limit value t2 (NO) in STEP 9, only the time s After waiting (STEP 11), the process proceeds to STEP 1 again to acquire temperature information from the temperature detector 25.

  That is, when the temperature T of the blow-down water becomes higher than the upper limit value T1, the opening of the first flow control valve device 26 is expanded to increase the flow rate of the cooling water flowing through the extraction line 20 and the discharge line 24, The temperature increase rate of the cooling water in the heat exchangers 17 and 18 is lowered. Further, when the temperature T of the blow-down water becomes lower than the lower limit value T2, the opening of the first flow control valve device 26 is narrowed to reduce the flow rate of the cooling water, and the cooling in the heat exchangers 17 and 18 is performed. Increase the water heating rate.

  When the temperature t of the cooling water flowing through the discharge line 24 is higher than the upper limit value t1, the low-temperature cooling water flowing through the extraction line 20 by expanding the road of the second flow rate control valve device 29 is supplied to the cooling water bypass 27. The liquid is branched and fluidized, and merged with high-temperature cooling water flowing in the discharge line 24. Thereby, the temperature of the cooling water downstream of the discharge line 24 can be lowered, and the occurrence of flushing when joining from the discharge line 24 to the condensate system 5 can be prevented. When the temperature t of the cooling water becomes lower than the lower limit value t2, the flow rate of the low-temperature cooling water flowing through the cooling water bypass path 27 is reduced by narrowing the opening of the second flow rate control valve device 29, The temperature of the cooling water downstream of the discharge line 24 can be increased.

  As shown above, since the temperature of the blowdown water cooled by the heat exchangers 17 and 18 is lower than the upper limit of the allowable range and higher than the lower limit of the allowable range, the blowdown water in the condensate demineralizer 7 is used. Desalination is performed efficiently. Further, the temperature of the cooling water discharged from the heat exchanger 17 to the discharge line 24 becomes lower than the upper limit value of the allowable range, and it is possible to prevent the occurrence of flushing when joining from the discharge line 24 to the condensate system 5. At the same time, the temperature of the cooling water discharged from the heat exchanger 17 to the discharge line 24 becomes higher than the upper limit of the allowable range, and the temperature drop when the cooling water joins the condensate system 5 from the discharge line 24 is suppressed. Therefore, a decrease in the thermal efficiency can be suppressed.

  Further, as shown in FIG. 3, the cooling water bypass line 27 may be arranged on the downstream side of the first flow control valve device 26. At this time, similarly to the case where the cooling water bypass line 27 shown in FIG. 1 is provided upstream of the first flow control valve device 26, the blow-down water can be sufficiently cooled, and the cooling water is supplied to the condensate system. It is possible to prevent a water hammer from being generated by flushing when the water 5 is combined with flowing water.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram showing the configuration of the power plant in the present embodiment. In the power plant of FIG. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the power plant of the present embodiment is discharged from the heat exchanger 18 to the configuration of the power plant (FIG. 1) of the first embodiment by shaft cold water that cools the shaft of the steam turbine 2. A heat exchanger 40 for cooling the blowdown water, a cooling water valve device 41a installed in the supply path to the axial cold water heat exchanger 40, and a discharge path from the axial cold water heat exchanger 40 The cooling water valve device 41b is added. Further, the heat exchangers 17, 18, 40, the first temperature detector 25, the second temperature detector 28, the first flow rate control valve device 26, the second flow rate control valve device 29, the flow rate control device 30, and the cooling water valve. The cooling control device 32 is configured by the devices 41a and 41b.

  When the power plant is configured in this way, the cooling control device 32 is configured such that the temperature of the blowdown water discharged from the heat exchanger 18 detected by the first temperature detector 25 is an allowable upper limit of the condensate demineralizer 7. When the temperature is exceeded and the opening degree of the flow control valve device 26 is maximum, it is recognized as an abnormal state, the cooling water valve devices 41a and 41b are opened, and the axial cold water is supplied to the heat exchanger 40. To do. When the temperature of the blow-down water discharged from the heat exchanger 18 detected by the first temperature detector 25 is equal to or lower than the allowable upper limit temperature of the condensate demineralizer 7, the cooling water valve devices 41a and 41b are used. Is closed, and the supply of the axial cold water to the heat exchanger 40 is shut off. The control operation of the flow control device 30 in the cooling control device 32 will be described with reference to the flowchart of FIG.

  Temperature information is acquired from a first temperature detector 25 that is installed in the discharge system 15 and is cooled by the heat exchangers 17 and 18 and measures the temperature of the blowdown water (STEP 1). The temperature T of the blowdown water discharged from the heat exchanger 18 measured by the detector 25 is confirmed. Then, the confirmed temperature T of the blowdown water is compared with the upper limit value T1 of the allowable range of the temperature of the blowdown water cooled by the heat exchangers 17 and 18 (STEP 2). When it is confirmed that the temperature T of the blowdown water is higher than the upper limit value T1 (YES), it is confirmed whether or not the opening degree of the first flow control valve device 26 is maximum (STEP 12). When it is confirmed that the opening degree of the first flow control valve device 26 is not the maximum (NO), a control operation for expanding the opening degree of the first flow control valve device 26 is performed (STEP 3). Further, when it is confirmed in STEP 12 that the opening degree of the first flow control valve device 26 is maximum (YES), the cooling water valve devices 41a and 41b are opened to supply axial cold water to the cooler 40 (STEP 13). .

  At this time, the opening degree of the first flow control valve device 26 may be increased by a predetermined amount, and the first flow control valve device 26 is controlled based on the temperature difference between the temperature T of the blowdown water and the upper limit value T1. The opening degree may be set.

  If it is confirmed in STEP 2 that the temperature T of the blowdown water is equal to or lower than the upper limit value T1 (NO), then the temperature T of the cooling water is changed to the temperature of the blowdown water discharged from the heat exchanger 18. Is compared with a lower limit value T2 (T2 <T1) of the allowable range (STEP 4). When it is confirmed that the temperature T of the blowdown water is lower than the lower limit value T2 (YES), a control operation for narrowing the opening degree of the first flow control valve device 26 is performed (STEP 5). At this time, the opening degree of the first flow control valve device 26 may be narrowed by a predetermined value, and the first flow control valve device 26 is controlled based on the temperature difference between the temperature T of the blowdown water and the lower limit value T2. The opening degree may be set.

  After setting the opening degree of the first flow control valve device 26 in STEP3 or STEP5 or after confirming that the temperature T of the blowdown water is not less than the lower limit value T2 (NO) in STEP4, from the heat exchanger 17 Temperature information is acquired from the second temperature detector 28 that measures the temperature of the cooling water discharged to the discharge line 24 (STEP 6), and the discharge line 24 measured by the second temperature detector 28 based on this temperature information. Check the temperature t of the cooling water. And the temperature of the cooling water which flows through the confirmed discharge line 24 is compared with the upper limit t1 of the allowable range of the temperature of the cooling water discharged from the heat exchanger 17 (STEP 7). When it is confirmed that the temperature t of the cooling water is higher than the upper limit value t1 (YES), a control operation for expanding the opening of the second flow control valve device 29 is performed (STEP 8). At this time, the opening degree of the second flow rate control valve device 29 may be increased by a predetermined amount, and the opening of the second flow rate control valve device 29 is based on the temperature difference between the temperature t of the cooling water and the upper limit value t1. You may make it set a degree.

  Further, if it is confirmed in STEP 7 that the temperature of the cooling water is equal to or lower than the upper limit value t1 (NO), then, the temperature t of the cooling water is changed to an allowable range of the temperature of the cooling water discharged from the heat exchanger 17. Is compared with a lower limit value t2 (t2 <t1) (STEP 9). When it is confirmed that the temperature t of the cooling water is lower than the lower limit value t2 (YES), a control operation for narrowing the opening degree of the second flow control valve device 29 is performed (STEP 10). At this time, the opening of the second flow control valve device 29 may be narrowed by a predetermined amount, and the opening of the second flow control valve device 29 is based on the temperature difference between the temperature t of the cooling water and the upper limit value t1. You may make it set a degree.

  After setting the opening of the second flow control valve device 29 in STEP 8 or STEP 10, or after confirming that the temperature t of the cooling water is equal to or higher than the lower limit value t2 (NO) in STEP 9, only the time s After waiting (STEP 11), the process proceeds to STEP 1 again to acquire temperature information from the temperature detector 25.

  As in the present embodiment, by finely managing the temperature of the blow-down water discharged from the heat exchanger 18, the power plant can be driven in a safer state than in the first embodiment.

  In this embodiment, as shown in FIG. 6, a third temperature detector 42 for detecting the temperature of blowdown water discharged from the heat exchanger 40 is provided, and the blow supplied to the condensate demineralizer 7 is provided. The temperature may be controlled so that the temperature of the down water does not exceed the allowable upper limit temperature. That is, when the temperature detector 42 detects that the temperature of the blow-down water discharged from the heat exchanger 40 is higher than the allowable upper limit temperature, the flow rate control device 30 causes the cooling water valve devices 41a and 41b. Is opened, axial cold water is supplied to the heat exchanger 40, and the temperature of the blow-down water discharged from the heat exchanger 40 is lowered. By doing in this way, the capability fall of the condensate demineralizer 7 can be prevented.

  In each of the above-described embodiments, the flow control device 30 determines the opening degree of the first flow control valve device 26 based on the temperature detected by the first temperature measuring device 25 and the first opening based on the temperature detected by the second temperature measuring device 28. Although the example which determines the opening degree of 2 flow control valve device 29 is illustrated, it is not limited to it, and the temperature measured with the 1st temperature measuring device 25 and the 2nd temperature measuring device 28 is integrated. Thus, the opening degree of the first flow control valve device 26 and the second flow control valve device 28 may be determined.

  The cooling control apparatus of the present invention can be applied to a plant that generates high-heat steam using a steam generator such as a nuclear power plant, a thermal power plant, or a combined plant.

These are block diagrams which show the structure of the power plant of 1st Embodiment. These are flowcharts which show the control operation | movement of the flow control apparatus in the power plant of FIG. These are block diagrams which show another structure of the power plant of 1st Embodiment. These are block diagrams which show the structure of the power plant of 2nd Embodiment. These are flowcharts which show the control operation | movement of the flow control apparatus in the power plant of FIG. These are block diagrams which show another structure of the power plant of 2nd Embodiment. These are block diagrams which show the structure of the conventional power plant.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reactor 2 Steam generator 3 Steam turbine 3a Generator 4 Condenser 5 Condensate system 6 Condensate pump 7 Condensate demineralizer 8 Condensate booster pump 9 Low-pressure feed water heater 10 Deaerator 12 Bypass path 13 1st 1 valve device 14 second valve device 15 discharge system 16 cooling unit 17, 18 heat exchanger 20 extraction line 21 flash tank 22 mist separator 23 supply pump 24 discharge line 25 first temperature detector 26 first flow control valve device 27 cooling Water bypass line 28 Second Indian detector 29 Second flow control valve device 30 Flow control device 31 Cooling control device

Claims (17)

A heat exchanger that cools a portion of the liquid blown down and discharged from a steam generator that heats the liquid and generates hot steam;
Cooling medium extraction that branches the liquid condensed in the condenser from a liquid supply path that supplies the steam generator and supplies a part of the liquid flowing in the liquid supply path to the heat exchanger as a cooling medium. Road,
A cooling medium discharge path that performs work in the heat exchanger and joins the liquid used as a cooling medium to the liquid supply path;
A bypass path connecting the cooling medium extraction path and the cooling medium discharge path;
A first temperature detector that measures the temperature of the liquid cooled by the heat exchanger;
A second temperature detector that is used as the cooling medium and measures the temperature of the liquid discharged from the heat exchanger to the cooling medium discharge path;
A cooling control device comprising: a first flow rate control valve that determines a flow rate of liquid flowing through the cooling medium discharge path; and a second flow rate control valve that determines a flow rate of liquid flowing through the bypass path;
Based on the temperature of the liquid used as the cooling medium detected by the first temperature detection unit and the temperature of the liquid detected by the second temperature detection unit, the first flow control valve and the second A cooling control device comprising: a flow rate control unit that sets an opening degree of a flow rate control valve and controls a flow rate of a liquid used as the cooling medium supplied to the heat exchanger.   When the temperature of the liquid cooled by the heat exchanger measured by the first temperature detector becomes higher than a first allowable upper limit value, the opening degree of the first flow rate control valve is widened, and the heat exchanger The cooling control apparatus according to claim 1, wherein the flow rate of the liquid serving as the cooling medium supplied to the apparatus is increased.   The liquid cooled by the heat exchanger is supplied to a demineralizer that removes impurities from the liquid, and the first allowable upper limit is a value set for the demineralizer. The cooling control device according to claim 2.   When the temperature of the liquid cooled by the heat exchanger measured by the first temperature detector becomes lower than a first allowable lower limit value, the opening degree of the first flow control valve is narrowed, and the heat exchanger 4. The cooling control device according to claim 1, wherein a flow rate of the liquid serving as the cooling medium supplied to the cooling medium is reduced. 5.   When the temperature of the liquid used as the cooling medium measured by the second temperature detection unit is higher than a second allowable upper limit value, the opening of the second flow rate control valve is widened, and the cooling medium extraction path The cooling control device according to any one of claims 1 to 4, wherein the flow rate of the liquid branched from the fluid and flowing into the bypass passage is increased.   When the temperature of the liquid used as the cooling medium measured by the second temperature detection unit is lower than a second allowable lower limit value, the opening of the second flow control valve is narrowed, and the cooling medium extraction path The cooling control device according to any one of claims 1 to 5, wherein a flow rate of the liquid branched from the fluid and flowing into the bypass path is reduced. A part of the liquid blown down from the steam generator that heats the liquid and generates high-temperature steam is cooled, and the liquid obtained by condensing the steam with the condenser is supplied to the steam generator. Cooling that passes through a liquid supply path, supplies a part of the liquid as a cooling medium to the heat exchanger, and joins the liquid used as a cooling medium that has performed work in the heat exchanger to the liquid supply path In the control method,
A first step of measuring the temperature of the liquid cooled by the heat exchanger;
A second step of measuring the temperature of the liquid used as the cooling medium discharged from the heat exchanger;
Based on the temperature of the liquid cooled by the heat exchanger detected in the first step, an opening of a first flow control valve for determining a flow rate of the liquid used as the cooling medium supplied to the heat exchanger. A third step of setting the degree;
Based on the temperature of the liquid used as the cooling medium detected in the second step, a part of the liquid used as the cooling medium supplied to the heat exchanger is discharged from the heat exchanger. A cooling control method comprising: a fourth step of setting an opening degree of a second flow rate control valve provided in a bypass passage for merging with the liquid used as the cooling medium.   When the temperature of the liquid cooled in the heat exchanger measured in the first step becomes higher than a first allowable upper limit value, the opening of the first flow control valve is increased and supplied to the heat exchanger. The cooling control method according to claim 7, wherein the flow rate of the liquid used as the cooling medium is increased.   When the temperature of the liquid cooled in the heat exchanger measured in the first step is lower than a first allowable lower limit value, the opening of the first flow control valve is narrowed and supplied to the heat exchanger. The cooling control method according to claim 7, wherein a flow rate of the liquid used as the cooling medium is reduced.   When the temperature of the liquid used as the cooling medium measured in the second step becomes higher than a second allowable upper limit value, the opening of the second flow rate control valve is widened to flow through the cooling medium extraction path. 10. The cooling control method according to claim 7, wherein the flow rate of the liquid branched and flowing into the bypass path out of the liquid used as the cooling medium is increased.   When the temperature of the liquid used as the cooling medium measured in the second step becomes lower than a second allowable lower limit value, the opening of the second flow rate control valve is narrowed to flow through the cooling medium extraction path. The cooling control method according to any one of claims 7 to 10, wherein a flow rate of a liquid branched and flowing into the bypass path among liquids used as the cooling medium is reduced. A steam generator that heats the liquid and generates hot steam;
A condenser for condensing the steam generated by the steam generator into a liquid;
A liquid supply path for supplying the liquid condensed in the condenser to the steam generator;
A heat exchanger that cools a portion of the liquid drained from the steam generator;
A cooling medium extraction path for supplying a part of the liquid passing through the liquid supply path to the heat exchanger as a cooling medium;
A cooling medium discharge passage for joining the liquid serving as a cooling medium that has performed work in the heat exchanger to the liquid supply path;
In a plant comprising a bypass path connecting the cooling medium extraction path and the cooling medium discharge path,
A first temperature detector that measures the temperature of the liquid cooled by the heat exchanger;
A second temperature detector that is used as the cooling medium and measures the temperature of the liquid discharged from the heat exchanger to the cooling medium discharge path;
A first flow rate control valve for determining a flow rate of the liquid flowing through the cooling medium discharge path; a second flow rate control valve for determining a flow rate of the liquid flowing through the bypass path;
Based on the temperature of the liquid cooled by the heat exchanger detected by the first temperature detection unit and the temperature of the liquid used as the cooling medium detected by the second temperature detection unit, the first A plant comprising: a flow rate control unit that sets an opening degree of the first flow rate control valve and the second flow rate control valve, and controls a flow rate of the liquid used as the cooling medium supplied to the heat exchanger. .   When the temperature of the liquid cooled by the heat exchanger measured by the first temperature detector becomes higher than a first allowable upper limit value, the opening degree of the first flow control valve is increased, and the heat exchanger The plant according to claim 12, wherein the flow rate of the liquid serving as the cooling medium supplied to the plant is increased.   When the temperature of the liquid cooled by the heat exchanger measured by the first temperature detection unit becomes lower than a first allowable lower limit value, the opening of the first flow control valve is reduced, and the heat exchanger The plant according to claim 12 or 13, wherein the flow rate of the liquid serving as the cooling medium supplied to the plant is reduced.   When the temperature of the liquid used as the cooling medium measured by the second temperature detection unit is higher than a second allowable upper limit value, the opening of the second flow rate control valve is widened, and the cooling medium extraction path The plant according to claim 12, 13 or 14, wherein the flow rate of the liquid that branches and flows into the bypass path among the liquid that is used as the cooling medium flowing through the pipe is increased.   When the temperature of the liquid used as the cooling medium measured by the second temperature detection unit is lower than a second allowable lower limit value, the opening of the second flow control valve is narrowed, and the cooling medium extraction path The plant according to any one of claims 12 to 15, wherein the flow rate of the liquid that branches and flows into the bypass path among the liquid that is used as the cooling medium flowing through the pipe is reduced.   The plant according to any one of claims 12 to 16, further comprising a desalination device that removes impurities from the liquid cooled by the heat exchanger.

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