JP4573315B2 - Condensate purification system and operation method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a condensate purification system and a method for operating the same in nuclear power plants and thermal power plants, and in particular, a condensate filtration device in a system in which a condensate filtration device and a condensate desalination device are connected in series to a condenser. The present invention relates to an operation method of a water flow system and a condensate filtration device.
[0002]
[Prior art]
Many condensate purification systems for thermal power plants and nuclear power plants pass a condensate filtration device and a condensate desalination device in series, and suspending impurities such as iron clad in the condensate are passed through the condensate filtration device. After removing ionic impurities with a condensate demineralizer, they are supplied to a boiler, a nuclear reactor or a steam generator.
[0003]
In recent years, for example, as a secondary water quality management method for a pressurized nuclear power plant (PWR), in order to reduce the iron clad concentration in the condensate, high pH operation in which the amount of ammonia added is increased, or monoethanol instead of ammonia. Alternative amine operation is planned to add amines.
[0004]
However, in high pH operation, the ion concentration at the condensate purification apparatus inlet is high, and it is difficult to treat the entire condensate with the condensate demineralizer. In alternative amine operation, the regeneration waste liquid of the condensate demineralizer contains high-concentration alternative amine, and it is necessary to perform more advanced treatment than conventional regeneration waste liquid. Is desirable.
For this reason, in plants that operate at high pH or alternative amines, the condensate demineralizer uses a part or all of the desalting tower as a standby or stop process, and bypasses all or part of the condensate. Operated.
[0005]
Thus, even in a plant that normally bypasses the condensate demineralizer, it is necessary to treat the entire amount of condensate with the condensate demineralizer when leakage of seawater used for cooling the condenser occurs. . For this reason, either reduce the number of condensate demineralization towers that pass through the water, or pass the entire condensate at a high flow rate, or in-service the condensate demineralization tower that has been stopped to pass the entire condensate. I have to.
[0006]
[Problems to be solved by the invention]
However, if the total amount of condensate is processed by the condensate demineralizer while reducing the number of condensate demineralization towers that flow when seawater leaks, the flow rate will be higher than that of the conventional system that does not perform bypass operation. Therefore, the system differential pressure of the condensate demineralizer increases, and there is a problem that the differential pressure of the entire condensate purification system exceeds the allowable value. In order to reduce the differential pressure, it is necessary to reduce the water flow rate by in-service the condensate demineralization tower that has been stopped. In addition, it is necessary to perform washing for a long time with system water or high-purity makeup water, which is difficult to implement in an emergency.
[0007]
In addition, it is possible to increase the allowable pressure difference by increasing the head of the condensate pump, but for that purpose, it is necessary to completely modify the large capacity condensate pump, which is difficult to implement in terms of cost and is realistic. is not.
[0008]
Therefore, an object of the present invention is to pay attention to the above-mentioned problems, and in a condensate purification system that performs bypass water flow of the condensate demineralizer at normal times, the entire amount of condensate is reduced by the condensate demineralizer. Condensate purification system that can keep the differential pressure of the entire system within an allowable value without substantially increasing the number of condensate demineralization towers to be used even when treatment is required And providing an operation method thereof.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the operation method of the condensate purification system of the present invention is such that the condensate from the condenser is passed in series in the order of the condensate filtration device and the condensate desalination device , and the normal operation is performed. In a method for operating a condensate purification system in a power plant, where a part of the condensate is sometimes bypassed through the condensate demineralizer, when the entire amount of condensate is treated by the condensate demineralizer, It consists of a method characterized in that part or all of the water is bypassed through the condensate filtration device.
[0010]
Further, the condensate purification system according to the present invention connects a condenser with a condensate filtration device and a condensate demineralizer in series, and a part of the condensate during normal operation with respect to the condensate demineralizer. Alternatively, in a condensate purification system having a bypass passage that bypasses the entire amount, the condensate filtration device bypasses a condensate filtration device that bypasses part or all of the condensate and the condensate demineralizer uses the condensate. When the entire amount is processed, the condensate filtration device is provided with a switching control means for switching to water flow to the bypass passage of the condensate filtration device that bypasses a part or the entire amount of the condensate. Consists of things.
[0011]
In such a system and its operation method, when it is necessary to treat the entire amount of condensate with a condensate demineralizer, such as when there is a seawater leak, a part or all of the condensate from the condenser is filtered. It is switched to a water passage that bypasses the device. By bypassing, the differential pressure as the condensate purification system is reduced, so that the differential pressure increase due to high flow rate water flow of the condensate demineralizer is offset. As a result, in the plant that is performing the condensate bypass treatment, the number of water condensate demineralization towers is not increased substantially or only the minimum necessary number of condensate demineralization towers is newly passed. It becomes possible to cope with seawater leaks promptly. At this time, there are no new cost factors such as raising the head of the condensate pump, changing the system allowable differential pressure, and changing the design pressure of the system, which can be easily implemented in an existing plant.
[0012]
Even when the condensate filtration device is bypassed, suspended impurities are removed by the condensate demineralizer, so that the quality of the treated water is maintained at a sufficiently high level. In addition, since it is not necessary to in-service the demineralization tower that has been stopped, it is possible to prevent deterioration of the quality of the treated condensate due to eluate from the ion exchange resin.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a condensate purification system in a power plant according to one embodiment of the present invention. FIG. 1 shows a normal condensate flow system by a thick line, and FIG. Each condensate system is shown. In FIG. 1 and FIG. 2, the high pressure turbine 2 is driven by the steam generated by the steam generator 1, and the used steam is sent to the condenser 4 through the moisture separation heater 3, and the condenser 4 It is cooled using. Condensate from the condenser 4 is returned to the steam generator 1 via the condensate circulation line 6 by the condensate pump 5. The condenser 4 includes a plurality of condensate filtration towers 7. A condensate filtration device 8 and a condensate demineralization device 10 including a plurality of condensate demineralization towers 9 are connected in series.
[0014]
The condensate filtration device 8 is provided with an inlet valve 11 and an outlet valve 12 for controlling the flow of water to each condensate filtration tower 7, and a part of the condensate with respect to the condensate filtration device 8. Alternatively, a condensate filtration device bypass passage 13 for bypassing the entire amount is provided, and a condensate filtration device bypass valve 14 capable of opening and closing the bypass passage 13 is provided in the bypass passage 13. The condensate demineralizer 10 is provided with an inlet valve 15 and an outlet valve 16 for controlling the flow of water to each condensate demineralizer 9, and the condensate demineralizer 10 is condensate. A condensate demineralizer bypass passage 17 for bypassing a part of the water is provided, and a condensate demineralizer bypass valve 18 capable of opening and closing the bypass passage 17 is provided in the bypass passage 17.
[0015]
The condensate filtration device bypass valve 14 and the condensate demineralizer bypass valve 18 are controlled to be opened and closed by a switching control means. That is, the condensate filtration device bypass valve 14 and the condensate demineralizer bypass valve 18 are controlled to open and close by a signal from the control device 19, and the control device 19 can detect seawater leak attached to the condenser 4. The operation of the condensate filtration device bypass valve 14 and the condensate demineralizer bypass valve 18 is controlled based on a signal from the salt detection facility 20.
[0016]
During normal operation, as shown in FIG. 1, the condensate from the condensate filtration device 8, a portion is bypassed with respect to the condensate demineralizer 10, for example a condensate booster pump 21, low-pressure feed water heater 22 The deaerator 23, the feed water pump 24, and the high-pressure feed water heater 25 are returned to the steam generator 1. Further, a normal blowdown water supply line 27 is provided between the steam generator 1 and the condenser 4, and the blowdown water treatment device 26 (for example, electric deionization) of the steam generator 1 is provided in the line 27. (Equipment) may be installed.
[0017]
The condensate purification system configured as described above is operated as follows.
During normal operation, for example, the condensate filtration device bypass valve 14 is fully closed, the inlet valve 11 and the outlet valve 12 are fully opened, and the condensate from the condenser 4 is passed through the condensate filtration device 8 in its entirety. water demineralizer bypass valve 18 is fully opened, the inlet valve 15 and outlet valve 16 is opened, a part of the inlet and outlet valves of the condensate demineralizer 9 (not shown) is opened, the majority Condensate demineralizer 10 is bypassed for condensate, and partial condensate treatment is performed for some condensate in one or several towers of condensate demineralizer 9 .
[0018]
When the seawater leaks, the seawater leak is detected by the salt detection facility 20, and the condensate demineralizer bypass valve 18 is fully closed by the switching control signal from the control device 19 based on the detection signal, so that the total amount of condensate is reduced. While being processed by the condensate demineralizer 10, the condensate filter bypass valve 14 is opened, and a part or all of the condensate from the condenser 4 is bypassed by the condensate filter 8.
[0019]
If the total amount of condensate is processed by the condensate demineralizer 10 without substantially increasing the number of condensate demineralizers 9 that pass water, the differential pressure in the condensate demineralizer 10 increases. Since the water filtration device 8 is switched to bypass water flow, the differential pressure in the condensate filtration device 8 is reduced. Therefore, the differential pressure reduction in the condensate filtration device 8 can absorb the differential pressure increase in the condensate demineralizer 10, and the differential pressure of the entire system is maintained within an allowable value. As a result, it is not necessary to in-service the new condensate demineralization tower 9, so that it is possible to quickly cope with seawater leaks.
[0020]
In the response by this switching, it is basically unnecessary to raise the head of the condensate pump 5, change the allowable differential pressure of the system, change the design pressure of the system, and the like, and there are no new cost factors resulting from these. Therefore, the existing plant can be easily implemented without a large capital investment.
[0021]
Even when bypass water is passed to the condensate filtration device 8 as described above, since the entire amount of condensate is passed through the condensate demineralizer 10 at that time, Suspended impurities are removed and a sufficiently high treated water quality is maintained. Further, since there is no need to newly in-service the condensate demineralization tower 9 that has been stopped, there is no possibility of deterioration of the condensate water quality due to the effluent from the ion exchange resin accompanying the new in-service.
[0022]
【The invention's effect】
As described above, according to the condensate purification system and the operation method thereof of the present invention, in a system that normally bypasses the condensate demineralizer, the total amount of condensate such as when seawater leaks is reduced. When it becomes necessary to treat with a condensate demineralizer, it can respond very quickly without any inconvenience. And since this invention does not require big equipment remodeling etc., it can implement easily with respect to the existing plant.
[Brief description of the drawings]
FIG. 1 is an equipment diagram showing a normal operation state of a condensate purification system according to an embodiment of the present invention.
FIG. 2 is an equipment system diagram showing a switching state when seawater leaks in the system of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steam generator 2 High pressure turbine 4 Condenser 5 Condensate pump 6 Condensate circulation line 7 Condensate filtration tower 8 Condensate filtration apparatus 9 Condensate demineralization tower 10 Condensate demineralization apparatus 11 Inlet valve 12 Outlet valve 13 Condensate Filtration device bypass passage 14 Condensation filtration device bypass valve 15 Inlet valve 16 Outlet valve 17 Condensate demineralization device bypass passage 18 Condensate demineralization device bypass valve 19 Control device 20 Salt detection facility 26 Blowdown water treatment device 27 Blowdown water Supply line

Claims (2)

Condensate from the condenser is passed in series in the order of the condensate filtration device and the condensate demineralizer, and a part of the condensate is bypassed through the condensate demineralizer during normal operation. In the operation method of the condensate purification system in the power plant, when the entire amount of condensate is processed by the condensate demineralizer, a part or the whole amount of the condensate is bypassed the condensate filtration device, How to operate the condensate purification system. Condensate having a bypass passage for connecting a condensate filtration device and a condensate demineralizer in series in this order to the condenser and bypassing a part of the condensate during normal operation with respect to the condensate demineralizer In the purification system, when the condensate filter bypasses the condensate filter and bypasses the condensate filter, and the condensate demineralizer processes the total amount of the condensate when the condensate is processed. A condensate purification system comprising switching control means for switching to water flow to a bypass passage of a condensate filtration device for bypassing a part or all of the condensate to the device.

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