JP2009243822A - Condenser tube cleaning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a condenser tube cleaning system, automatically determining the stop of back washing and securing a longer time for back washing. <P>SOLUTION: A control part determines whether an intake-drain temperature difference is more than a reference intake-drain temperature difference (S16). Subsequently, when the intake-drain temperature difference is more than the reference intake-drain temperature difference, it is determined whether the drain temperature rise rate is under a preset reference drain temperature rise rate (S20). When the drain temperature rise rate is more than the reference drain temperature rise rate, back washing of the condenser is stopped (S24). On the other hand, when the drain temperature rise rate is under the reference drain temperature rise rate, back washing of the condenser is continued (S12). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a condenser cleaning system. Specifically, even if the intake water temperature difference is equal to or greater than the standard intake water temperature difference, the backwash treatment time can be reduced by continuing the backwash process when the wastewater temperature increase rate is less than the preset standard wastewater temperature increase rate. It relates to a condenser cleaning system secured for a longer time.

  In power plants, condensers that condensate by cooling and condensing steam discharged from a steam turbine are widely used. This condenser is composed of a plurality of water chambers into which steam of the turbine is introduced, a large number of thin tubes penetrating the water chambers, piping for supplying cooling water (mainly seawater) to the thin tubes, and the seawater inside the narrow tubes. And a switching valve for switching the flow direction. Steam discharged from the turbine is introduced into the water chamber of the condenser and contacts the outer peripheral surface of the narrow tube. At this time, since the seawater is flowing inside the narrow tube, the steam in contact with the narrow tube is cooled and condensed.

  Here, as described above, seawater is often used as the cooling water flowing in the condenser thin tube. Normally, marine organisms such as microorganisms and garbage are contained in seawater, and when these marine organisms flow through the inside of the narrow tube, they may adhere to the inner surface of the narrow tube. The adhering matter or the like inhibits the smooth flow of the cooling water inside the narrow tube, reduces the flow rate of the seawater flowing inside the narrow tube, and lowers the cooling efficiency.

  Therefore, in order to remove the dust and marine organisms contained in the seawater adhering to the inner surface of the narrow tube, a so-called backwashing process is carried out to remove the dust and marine organisms in the seawater adhering to the inner surface of the thin tube by reversing the flow of the capillary tube. (See Patent Document 1 and Non-Patent Document 1). Since the temperature difference between intake and drainage rises during the backwash process, the backwash process is performed for a certain specified time, and then switched to condensate treatment to comply with the difference in intake and discharge temperature specified by the environmental regulations. .

JP 2000-356479 A http://www.chuden.co.jp/torikumi/atom/hamaoka/detail/131/data/unten0222.pdf

  However, in the above-described backwashing method, it is left to the operator to determine whether or not to stop the backwashing process, and it is performed while constantly monitoring the change graph of the intake / drain temperature difference displayed on the monitor. ing. Therefore, the worker must always monitor the monitor, and there is a problem that the burden on the worker is large.

  Further, the backwashing process is performed based on a preset time for the backwashing process, but the timing of stopping the backwashing process varies slightly depending on the operator. In particular, when considering the temperature rise of the time (recovery time) from when the backwash process is stopped to when the condensate process is started, the operation timing for stopping the backwash process is often different among workers. . In such a case, it is necessary to take measures such as suppression of power generation output due to the difference in intake and drainage temperature defined by the environmental regulation values, and it is not possible to secure sufficient operation time for the backwash process. Therefore, there is a problem that the inside of the narrow tube is not sufficiently cleaned and the cooling function in the condensate treatment of the condenser cannot be sufficiently recovered.

  Further, the condenser described in Patent Document 1 discloses a cleaning process inside the condenser pipe of the condenser, but does not disclose any stop timing of the cleaning process.

  Accordingly, the present invention has been made in view of the above problems, and its purpose is to automatically determine whether to stop the backwash process and to ensure a longer backwash process time. Is to provide.

  In order to solve the above-mentioned problems, the present invention provides a first method for measuring the intake temperature of cooling water supplied to the condenser during backwashing of the condenser for condensing steam discharged from the turbine. A temperature measuring unit; a second temperature measuring unit that measures a drain temperature of the cooling water drained from the condenser during the backwash process; and the water intake measured by the first and second temperature measuring units. A control unit that calculates a difference in intake and discharge temperature based on the temperature and the drainage temperature, and calculates a drainage temperature increase rate based on the drainage temperature measured by the second temperature measurement unit, and the control unit Is characterized by controlling the stop timing of the backwash process based on the drainage temperature increase rate when the intake / drainage temperature difference is greater than or equal to the reference intake / drainage temperature difference.

  A control part stops the backwash process of the said condenser, when the said drainage temperature rise rate is more than the preset reference | standard drainage temperature rise rate.

  The difference in the temperature of the standard drainage water is, for example, 6.6 ° C., and the rate of increase in the waste water temperature is, for example, 0.1 ° C./min.

  In this invention, the control unit determines whether or not the intake / drain temperature difference is equal to or greater than the reference intake / drain temperature difference. Conventionally, when the calculated difference in intake and drainage temperature is greater than the reference intake and drainage temperature difference, the temperature rise of the time (recovery time) from the stop of the condenser backwash process to the start of the condensate process is considered. The backwash process was stopped. On the other hand, in the present invention, even if the intake / drain temperature difference is greater than or equal to the reference intake / drain temperature difference, it is further determined whether the drainage temperature increase rate is less than a preset reference drainage temperature increase rate. This is because when the drainage temperature rise rate is less than the reference drainage temperature rise rate, the time for reaching the environmental regulation value is delayed by the difference, and thus the time for backwashing treatment can be extended.

  In this way, if it is determined whether or not to stop the backwash process by predicting the difference in intake and drainage temperature in consideration of the rate of increase in drainage temperature, the reverse will occur if the difference in intake and discharge temperature is greater than the reference difference in intake and discharge temperature. The time for backwashing treatment can be ensured longer than the conventional method of stopping the washing treatment.

  According to the present invention, a longer backwash treatment time can be secured, so that the inside of the condenser thin tube can be sufficiently washed, and the condenser cooling function can be maintained and recovered.

  Further, according to the present invention, since the control unit determines and executes the stop of the backwash process, compared with the case where the operator determines the timing of stopping the backwash process, the backwash process can be performed more accurately and quickly. Judgment of continuation or stoppage is made, and environmental regulations can be reliably observed. In addition, since the operator does not have to stop the backwash process, the burden on the operator is reduced. As a result, work efficiency can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
(Configuration of condenser cleaning system)
FIG. 1 is a diagram showing a schematic configuration of a main part in a condenser cleaning system 50 during backwashing processing according to an embodiment of the present invention.

  The condenser cleaning system 50 is applied to a steam turbine system of a nuclear power plant. As shown in FIG. 1, the condenser cleaning system 50 includes a condenser 10 that condenses water by cooling and condensing exhaust discharged from a steam turbine (not shown), and a condenser 10. During the backwash process, a first temperature measurement unit 18 that measures the temperature of the cooling water supplied to the condenser 10 and a second temperature measurement that measures the temperature of the cooling water drained from the condenser 10. Unit 20 and a control unit 16 that controls the cleaning system of the condenser 10 and the like.

  The condenser 10 has a box-shaped housing made of copper or the like. As is well known, a plurality of flat plates are arranged in parallel in the surface direction inside the housing, and a large number of cylindrical capillaries are provided so as to penetrate these flat plates (not shown). In this example, the inside of the housing provided with the thin tubes is separated into two systems, water chamber A and water chamber B, so that condensate treatment and backwash treatment can be performed independently for each system. Yes.

  An intake pipe 28 for supplying the collected seawater to the condenser 10 is connected to the intake 10 a of the condenser 10, and the seawater used for cooling in the condenser 10 is connected to the drain 10 b of the condenser 10. A drain pipe 30 for draining is connected. The intake pipe 28 and the drain pipe 30 are connected to a thin pipe (not shown) of the condenser 10. In this example, the intake pipe 28 and the drain pipe 30 are branched into two and connected to the water chamber A and the water chamber B, respectively. A backwash valve 14 for controlling the flow direction of the cooling water inside the narrow pipe of the condenser 10 is installed in the path (intersection) of the branched intake pipe 28 and drain pipe 30.

  When the valve direction of the backwash valve 14 is switched (the direction of the broken line in FIG. 1), the flow path of the intake pipe 28 and the drain pipe 30 on the backwash valve 14 side is switched, and the condenser side (downstream) from the backwash valve 14. The intake pipe on the side) functions as a drain pipe, and the drain pipe on the condenser side (upstream side) functions as an intake pipe. Thereby, in this example, it switches from a backwash process to a condensate process.

  For example, a temperature sensor is used as the temperature measurement unit. In this example, the intake side temperature sensor 18 (first temperature measurement unit) is installed at a predetermined position before the intake pipe 28 is branched, and measures the seawater temperature immediately before being supplied to the condenser 10. The drain side temperature sensor 20 (second temperature measuring unit) is installed at a predetermined position after the drain pipe 30 is joined, and measures the temperature of the drainage discharged from the condenser 10. The intake side temperature sensor 18 and the drain side temperature sensor 20 are installed in each of the intake pipe 28 and the drain pipe 30 at positions separated from the condenser 10 by substantially the same distance in order to make the temperature measurement conditions the same. . Measurement values (temperature data of water intake and drainage) in the water intake side temperature sensor 18 and the water discharge side temperature sensor 20 are supplied to the sequential control unit 16.

  As is well known, the control unit 16 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The CPU controls the overall operation of the condenser cleaning system 50. The ROM stores a control program, reference intake / drain temperature difference data, which will be described later, and reference drainage temperature rise rate data. The operation of the control unit 16 will be described later. As described above, the control unit 16 is connected to the backwash valve 14, the intake side temperature sensor 18, the drain side temperature sensor 20, and the timer 22, and further includes the display unit 24 and the input unit 26 via the interface 32. It is connected.

  The display unit 24 is configured by a display device such as an LCD (Liquid Crystal Display), for example, generates an image signal based on the temperature data of water intake and drainage supplied from the control unit 16, and an image based on the image signal. Is displayed on the LCD screen. For example, an LCD screen displays a graph of intake / drain temperature difference and a graph of a drainage temperature rise rate based on intake and drain temperature data, which will be described later.

  The timer 22 measures the operation time of the backwash process of the condenser 10, and when a valve switching signal is supplied from the control unit 16 to the backwash valve 14, the preset backwash process is performed. Count the driving time. Then, after the operation time has elapsed, the valve switching signal of the backwash valve 14 is supplied to return to the original normal condensate treatment.

The input unit 26 is configured by, for example, a keyboard or a touch panel, and when an input operation for switching to backwashing processing is performed by an operator, an input signal based on this operation is supplied to the control unit 16.
(Operation during backwash process)
Next, the operation | movement of the backwash process of the condenser 10 mentioned above is demonstrated. FIG. 2 is a flowchart showing the operation of the control unit 16 and the temperature sensor during the backwash process of the condenser 10.

  In step S <b> 10, when the backwashing process is selected from the keyboard of the input unit 26 by the operator, the control unit 16 supplies the backwash valve 14 with a switching signal for switching the valve direction to the backwashing process. The backwash valve 14 switches the direction of the backwash valve 14 based on the supplied switching signal. Thereby, a backwash process is started.

  In step S <b> 12, the control unit 16 determines whether the backwash process is within a preset specified operation time. The specified operation time is set to a time such that a later-described intake / drain temperature difference is less than a temperature determined by the environmental regulation value. In this example, the specified operation time for the backwash process is set to 15 minutes so that the inside of the condenser 10 can be sufficiently cleaned and the environmental regulation values can be observed. The specified operation time varies depending on the processing capacity of the condenser 10. The specified operation time may be directly input by the operator from the input unit 26 at the start of the backwash process, or may be stored in advance in the storage unit in the control unit 16.

  When it is determined that the backwash process is within the specified operation time, the control unit 16 proceeds to step S14. On the other hand, when it is determined that the backwash process exceeds the specified operation time, the process proceeds to step S24, and the control unit 16 automatically stops the operation of the backwash process.

  In step S <b> 14, the intake side temperature sensor 18 measures the intake temperature of the seawater flowing inside the intake pipe 28, and supplies the measured intake temperature data to the control unit 16. Similarly, the drain side temperature sensor 20 measures the drain temperature of seawater flowing inside the drain pipe 30 and supplies the measured drain temperature data to the control unit 16.

  In step S <b> 15, the control unit 16 calculates the intake water temperature difference based on the intake water temperature supplied from the intake water temperature sensor 18 and the waste water temperature supplied from the waste water temperature sensor 20. The intake / drain temperature difference data may be displayed on the screen of the display unit 24 so that the operator can monitor it.

  In step S16, the control unit 16 determines whether or not the calculated intake / discharge temperature difference is equal to or greater than a preset reference intake / discharge temperature difference. The reference intake / drain temperature difference is set based on, for example, the rising temperature of the wastewater after stopping the backwash process and the intake / drain temperature difference determined by the environmental regulations described above. In this example, it is assumed that the time (recovery time) from the stop of the backwash treatment operation to the recovery to the condensate treatment is 3 minutes, and the temperature rise of the waste water rises by 0.3 ° C. (0 .1 ° C / min), and the temperature difference between the standard intake and drainage specified by environmental regulations is 7.0 ° C. In addition, the reference intake / drain temperature difference is set to 6.6 ° C. with some allowance for the reference intake / drain temperature difference.

  When it is determined that the calculated intake / drain temperature difference is less than 6.6 ° C., the control unit 16 returns to step S12 and continues the operation of the backwash process. On the other hand, if the control unit 16 determines that the calculated intake / drain temperature difference is 6.6 ° C. or more, the control unit 16 proceeds to step S18.

  In step S <b> 18, the control unit 16 calculates the drainage temperature increase rate based on the drainage temperature supplied from the drainage temperature sensor 20. The drainage temperature rise rate data may be displayed on the screen of the display unit 24 so that the operator can monitor it.

  In step S20, the control unit 16 determines whether or not the calculated drainage temperature increase rate is equal to or higher than a preset reference drainage temperature increase rate. In this example, the reference discharge temperature increase rate is set to 0.1 ° C./min as described above. If the controller 16 determines that the calculated drain temperature rise rate is 0.1 ° C./min or more, the controller 16 proceeds to step S24. When the temperature is 0.1 ° C / min or more, the temperature difference after stopping the backwash process will reach or exceed 7 ° C (standard drainage temperature rise rate) due to the temperature rise after the stoppage of the backwash process. The backwash process is stopped even within the specified operation time (15 minutes). In step S26, the control unit 16 stops the backwashing process, and then switches the backwashing valve 14 to start (returns) the condensate process.

  On the other hand, if the control unit 16 determines that the calculated drainage temperature increase rate is less than 0.1 ° C., the control unit 16 returns to step S12 and continues the backwash process. In this case, even if the temperature difference between the intake and drainage is 6.6 ° C. or more, the drainage temperature rise rate is less than 0.1 ° C./min. The temperature difference between intake and drainage is less than 6.9 ° C. Therefore, the operation time of the backwash process can be extended by the difference between the reference drainage temperature increase rate and the calculated drainage temperature increase rate.

  In the present embodiment, first, the control unit 16 determines whether or not the intake / drain temperature difference is greater than or equal to the reference intake / drain temperature difference. Conventionally, when the calculated intake / drain temperature difference is equal to or greater than the reference intake / drain temperature difference, the temperature rise of the time (recovery time) from the stop of the backwash process of the condenser 10 to the start of the condensate process is increased. The backwash process was stopped in consideration. On the other hand, in this embodiment, even if the intake / drain temperature difference is greater than or equal to the reference intake / drain temperature difference, it is further determined whether the drainage temperature increase rate is less than a preset reference drainage temperature increase rate. This is because when the drainage temperature rise rate is less than the reference drainage temperature rise rate, the slope of the drainage temperature rise rate is smaller than the slope of the reference drainage temperature rise rate, and the time to reach the environmental regulation value is delayed by that difference. This is because the time for backwashing can be extended.

  In this way, if it is determined whether or not to stop the backwash process by predicting the difference in intake and drainage temperature in consideration of the rate of increase in drainage temperature, the reverse will occur if the difference in intake and discharge temperature is greater than the reference difference in intake and discharge temperature. A longer time can be ensured as the backwashing treatment time than the conventional method of stopping the washing treatment.

  Further, according to the present embodiment, the backwash treatment time can be extended, so that the inside of the thin tube of the condenser 10 can be sufficiently washed, and the initial cooling function of the condenser 10 can be maintained and recovered.

  Furthermore, according to the present embodiment, since the control unit 16 determines and executes the stop of the backwashing process, it is more accurate and quick than the case where the operator determines the timing for stopping the backwashing process. Judgment of continuation or stop of the washing process is made, and the environmental regulation values can be reliably observed. In addition, since the operator does not have to stop the backwash process, the burden on the operator is reduced. As a result, work efficiency can be improved.

[Second Embodiment]
Next, the present embodiment will be described with reference to the drawings.
This embodiment is different from the above-described first embodiment in the position where the temperature sensor is installed. In addition, since the structure of the other condenser washing | cleaning system 50 is the same as 1st Embodiment mentioned above, the same code | symbol is attached | subjected to a common component and detailed description is abbreviate | omitted.

FIG. 3 is a diagram showing the configuration of the condenser cleaning system 50 during backwashing processing according to an embodiment of the present invention.
As shown in FIG. 3, the water intake side temperature sensor 18 is installed in the water intake pipe 28 in the vicinity of the water intake port 10 a of each of the water chamber A and the water chamber B of the condenser 10. Similarly, the drain side temperature sensor 20 is installed in the drain pipe 30 in the vicinity of each drain port 10b of the water chamber A and the water chamber B of the condenser 10.

  The intake side temperature sensor 18 and the drain side temperature sensor 20 are respectively connected to the control unit 16 and supply the measured intake temperature data and drainage temperature data to the control unit 16. Here, when backwashing the two systems of the water chamber A and the water chamber B of the condenser at the same time, the average of the intake water temperature data supplied from the two intake water temperature sensors 18 is calculated, and this calculation is performed. The average temperature can be taken as water temperature data. Further, the higher intake water temperature data may be used as a reference. On the other hand, when only one system of the water chamber A or the water chamber B of the condenser 10 is backwashed, from the water intake side temperature sensor 18 installed in the vicinity of the water intake 10a of the water chamber A during the backwashing treatment. The supplied temperature data is taken as water temperature data. The same applies to the drain side temperature sensor 20, and the description thereof is omitted.

  Also in this embodiment, the same operational effects as in the first embodiment can be obtained.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention.

  For example, the above-mentioned values of intake / drain temperature difference and drainage temperature rise rate are examples, and if the value of intake / drainage temperature difference and drainage temperature rise rate changes depending on the environment and season, adapt to these changes. It is possible to set the value of the temperature difference between intake and drainage and the rate of increase in drainage temperature.

  The condenser cleaning system of the present invention can be suitably applied to a condenser that condenses exhaust gas from a steam turbine used in a thermal power plant or a nuclear power plant.

It is a figure which shows schematic structure of the condenser washing | cleaning system which concerns on one Embodiment of this invention. It is a flowchart which shows operation | movement of the control part at the time of a backwash process. It is a figure which shows schematic structure of the condenser washing | cleaning system which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Condenser, 14 ... Backwash valve, 16 ... Control part, 18 ... Intake side temperature sensor, 20 ... Drain side temperature sensor, 22 ... Timer, 24 ... Display part, 26 ... Input part, 28 ... Intake pipe 30 ... Drain pipe, 32 ... Interface, 50 ... Condenser cleaning system

Claims (5)

A first temperature measurement unit that measures the intake temperature of cooling water supplied to the condenser during backwashing of the condenser that condenses steam discharged from the turbine, and the condenser during the backwashing process. A second temperature measuring unit for measuring a drainage temperature of the cooling water drained from the water vessel;
The difference between intake and drainage temperature is calculated based on the intake water temperature and the drainage temperature measured by the first and second temperature measurement units, and drainage is performed based on the drainage temperature measured by the second temperature measurement unit. A controller for calculating the rate of temperature rise,
The controller is
The condenser cleaning system, wherein the backwashing process stop timing is controlled based on the drainage temperature increase rate when the intake / drainage temperature difference is equal to or greater than a reference intake / drainage temperature difference. The controller is
The condenser cleaning system according to claim 1, wherein when the drainage temperature increase rate is equal to or higher than a preset reference drainage temperature increase rate, the backwash process of the condenser is stopped. The reference intake / drain temperature difference is
It is set based on the drainage temperature rise rate of the waste water after stopping the backwash process and the time from the stop of the backwash process to the start of the condensate process. Condenser cleaning system as described. The standard drainage temperature rise rate is
The condenser cleaning system according to claim 1, wherein the condenser cleaning system is set based on a drainage temperature increase rate of drainage after the backwash treatment is stopped. A timer for measuring the processing time of the backwash process;
The timer supplies a stop signal for stopping the backwash process to the control unit after elapse of a preset specified operation time,
The condenser cleaning system according to claim 1, wherein the control unit stops the backwash process based on the supplied stop signal.

Images