A nuclear island demineralized water system and method of operation

Abstract

The application provides a nuclear island desalted water system, which comprises a desalted water tank, a fourth pipeline connected to the desalted water tank, a third valve arranged on the fourth pipeline, a first pipeline connected to an outlet of the fourth pipeline, a first desalted water pump and a first valve arranged on the first pipeline in sequence, a fifth pipeline connected to an outlet of the first pipeline, and a pressure switch arranged on the fifth pipeline; an inlet of a third pipeline is connected to the fourth pipeline between the third valve and the outlet of the fourth pipeline, and an outlet of the third pipeline is connected to the fifth pipeline between the outlet of the first pipeline and the pressure switch; a pressure stabilizing pump and a pressure stabilizing tank are arranged on the third pipeline in sequence. The application further provides a working method of the nuclear island desalted water system. The system and the method provided by the application can achieve the purpose of energy saving and consumption reduction.

Description

Technical Field

[0001] This invention relates to the field of nuclear island demineralized water systems, and more particularly to a nuclear island demineralized water system and its operating method. Background Technology

[0002] The demineralized water system of a nuclear power plant is divided into two parts: the nuclear island demineralized water supply system (SED) and the conventional island demineralized water supply system (SER). These systems supply demineralized water that meets the required pressure, flow rate, and water quality to the systems within the nuclear island and conventional island, respectively. Each demineralized water system consists of one or two tanks, two centrifugal pumps, and corresponding piping and valves. The system is designed to operate with the demineralized water pumps running continuously to maintain the pressure in the demineralized water network and to provide demineralized water flow when there is a demand in the network. Normally, one demineralized water pump operates continuously. A second pump is activated when the operating pump trips or when the demand for demineralized water in the network is too high for one pump to meet the required flow rate.

[0003] The original nuclear power plant's demineralized water supply system for the nuclear island and the demineralized water supply system for the conventional island each had two demineralized water pumps. To meet the high water flow demand, the demineralized water pumps were of relatively high power; the nuclear island demineralized water pump had a rated flow rate of 100 m³ / h. 3 / h, rated power is 30kW; the rated flow rate of the conventional island demineralized water pump is 265m³ / h. 3 / h, rated power is 90kW. Long-term statistics show that the demineralized water system in nuclear power plants uses very little water most of the time; the daily supply of demineralized water to the nuclear island is approximately 1m³. 3 / h, the demineralized water flow rate of a typical island is approximately 3m³ / h. 3 / h. The demineralized water pumps on the nuclear island supply approximately 1m³ / h. 3 Under normal operating conditions ( / h), the actual power consumption of the demineralized water pumps in the nuclear island reaches approximately 17kW. This is because the centrifugal pumps are not operating in their optimal efficiency range, and most of the motor power is consumed in maintaining the minimum flow rate required for the centrifugal pumps (through the low-flow circulation pipeline). Conventional island demineralized water pumps operate at a supply flow rate of approximately 3m³ / h. 3 Under normal operating conditions, the actual power consumption of a conventional island demineralized water pump reaches approximately 58kW. This is because the centrifugal pump is not operating in its optimal efficiency range, and most of the motor power is consumed to maintain the minimum flow rate required for the centrifugal pump to operate normally (through a small-flow circulation pipeline). Therefore, using a high-power demineralized water pump to maintain the pipeline pressure is extremely wasteful. Summary of the Invention

[0004] The purpose of this invention is to provide a nuclear island demineralized water system that solves the problem of low efficiency and energy waste caused by the demineralized water pump operating at a flow rate far below the rated flow rate for a long time, which is mismatched with the demineralized water load characteristics. This invention achieves energy saving and consumption reduction in the nuclear island demineralized water system.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A nuclear island demineralized water system includes a demineralized water tank connected to a fourth pipe, a third valve on the fourth pipe, a first pipe connected to the outlet of the fourth pipe, a first demineralized water pump and a first valve sequentially mounted on the first pipe, a fifth pipe connected to the outlet of the first pipe, and a pressure switch mounted on the fifth pipe; the inlet of the third pipe is connected to the fourth pipe between the third valve and the outlet of the fourth pipe, and the outlet is connected to the fifth pipe between the outlet of the first pipe and the pressure switch; a pressure stabilizing pump and a pressure stabilizing tank are sequentially mounted on the third pipe.

[0007] As one possible implementation, the system also includes a second pipeline, the inlet of which is connected to the outlet of the fourth pipeline and the outlet of which is connected to the outlet of the first pipeline, and a second demineralized water pump and a second valve are sequentially installed on the second pipeline.

[0008] In one possible implementation, the pressure switch includes a first pressure switch, a second pressure switch, a third pressure switch, and a fourth pressure switch arranged sequentially.

[0009] As one feasible approach, the pressure-stabilizing pump is a variable frequency pressure-stabilizing pump.

[0010] As one possible implementation, the first valve is a shut-off valve.

[0011] As one possible implementation, the second valve is a shut-off valve.

[0012] As one possible implementation, the third valve is a shut-off valve.

[0013] A method for operating a nuclear island demineralized water system includes:

[0014] The pressure stabilizing pump automatically starts when the demineralized water network pressure is lower than the pressure P3 of the third pressure switch, and automatically stops when the demineralized water network pressure is higher than the pressure P4 of the fourth pressure switch. Normally, during periods without large water flow, the demineralized water network pressure is maintained between the pressures P3 and P4.

[0015] When the water consumption of the demineralized water network increases and the pressure of the demineralized water network decreases to the pressure P2 of the second pressure switch, the first demineralized water pump starts; if the demineralized water flow continues to increase, when the pressure of the demineralized water network decreases to the pressure P1 of the first pressure switch, the second demineralized water pump starts.

[0016] When the high-flow-rate demineralized water usage ends, and the pressure in the demineralized water network rises to the pressure P3, the first and second demineralized water pumps automatically stop operating and wait for the next high-flow-rate water usage to restart.

[0017] Compared with the prior art, the nuclear island demineralized water system and working method provided by the present invention have the following beneficial effects:

[0018] The system provided by this invention uses a low-power, low-energy-consumption pressure-stabilizing pump for pipeline pressure stabilization, and a high-power first demineralized water pump to cope with short-term sudden large flow demand. In this way, most of the time, the high-power first and second demineralized water pumps are kept out of service and only the pressure-stabilizing pump is kept running, so as to achieve the purpose of energy saving and consumption reduction.

[0019] The method provided by this invention has any of the advantages of the above-described system. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the nuclear island demineralized water system provided in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Demineralized water tank; 2. First demineralized water pump; 3. First valve; 4. Second demineralized water pump; 5. Second valve; 6. Pressure stabilizing pump; 7. Pressure stabilizing tank; 8. Third valve; 9. First pressure switch; 10. Second pressure switch; 11. Third pressure switch; 12. Fourth pressure switch; 13. Fourth pipeline; 14. First pipeline; 15. Second pipeline; 16. Third pipeline; 17. Fifth pipeline; 18. Fourth pipeline outlet; 19. First pipeline outlet. Detailed Implementation

[0024] Although the nuclear island demineralized water system of the present invention can be implemented in many different ways, exemplary embodiments will be described in detail herein with reference to the accompanying drawings. It is to be understood that the description herein should be considered as illustrative of the nuclear island demineralized water system and is not intended to limit the scope of protection of the invention to the exemplary embodiments. Therefore, in essence, the accompanying drawings and the description of specific embodiments should be considered as illustrative rather than limiting of the invention. In the description of the invention, terms such as "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] The following detailed description provides further details on specific implementation methods.

[0026] like Figure 1 As shown, this invention provides a nuclear island demineralized water system, including a demineralized water tank 1, a fourth pipe 13 connected to the demineralized water tank 1, a third valve 8 installed on the fourth pipe 13, a first pipe 14 connected to the fourth pipe outlet 18, a first demineralized water pump 2 and a first valve 3 sequentially installed on the first pipe 14, a fifth pipe 17 connected to the first pipe outlet 19, and a pressure switch installed on the fifth pipe 17. The inlet of a third pipe 16 is connected to the fourth pipe 13 between the third valve 8 and the fourth pipe outlet 18, and the outlet of the third pipe 16 is connected to the fifth pipe 17 between the first pipe outlet 19 and the pressure switch. A pressure stabilizing pump 6 and a pressure stabilizing tank 7 are sequentially installed on the third pipe 16. Figure 1 As shown, the nuclear island demineralized water system of the present invention is connected to the demineralized water pipeline network (downstream demineralized water users and corresponding pipelines).

[0027] This invention, by adding a pressure-stabilizing pump 6 and a pressure-stabilizing tank 7, ensures that when there is no large flow of water, only the low-power booster pump 6 operates to provide a small flow of water and maintain the pipeline pressure, while the high-power first demineralized water pump 2 remains shut down, achieving energy saving and consumption reduction. The first demineralized water pump 2 automatically starts when there is a large flow of water and automatically shuts down after the large flow of water usage ends. The pressure-stabilizing pump 6 and the first demineralized water pump 2 are automatically controlled to start and stop based on the pressure gauge at the demineralized water main pipe.

[0028] Preferably, the system provided by the present invention further includes a second pipe 15, the inlet of which is connected to the outlet 18 of the fourth pipe, and the outlet of which is connected to the outlet 19 of the first pipe. A second demineralized water pump 4 and a second valve 5 are sequentially installed on the second pipe 15. The second pipe 15 is configured to meet the demand for larger flow rates of water.

[0029] like Figure 1 As shown, the pressure switches include a first pressure switch 9, a second pressure switch 10, a third pressure switch 11, and a fourth pressure switch 12, arranged sequentially on the fifth pipe 17. The pressure value of the first pressure switch 9 is set to P1, the pressure value of the second pressure switch 10 is set to P2, the pressure value of the third pressure switch 11 is set to P3, and the pressure value of the fourth pressure switch 12 is set to P4. The set values ​​of each pressure switch are in the order P1 < P2 < P3 < P4. The pressure values ​​of the pressure switches can be adjusted according to the actual application.

[0030] Preferably, the pressure stabilizing pump 6 is a variable frequency pressure stabilizing pump. By using a variable frequency pressure stabilizing pump, energy saving and consumption reduction can be further achieved.

[0031] Preferably, the first valve 3 is a stop valve, the second valve 5 is a stop valve, and the third valve 8 is a stop valve.

[0032] In addition, the present invention also provides a method for operating a nuclear island demineralized water system, comprising:

[0033] When the pressure in the demineralized water pipeline is lower than the pressure setpoint P3 of the third pressure switch 11, the pressure stabilizing pump 6 sends a start signal to the third pressure switch 11. The pressure stabilizing pump 6 starts automatically after receiving the start signal. When the pressure in the demineralized water pipeline is higher than the pressure setpoint P4 of the fourth pressure switch 12, the fourth pressure switch 12 sends a stop signal to the pressure stabilizing pump 6. The pressure stabilizing pump 6 stops automatically after receiving the stop signal. Normally, during periods without large-flow water usage, the pressure in the demineralized water pipeline is maintained between pressure P3 and pressure P4.

[0034] When the water consumption of the demineralized water network increases and the pressure of the demineralized water network decreases to the pressure setpoint P2 of the second pressure switch 10, the second pressure switch 10 sends a start signal, which is sent to the first demineralized water pump 2. The first demineralized water pump 2 starts automatically after receiving the start signal. If the demineralized water flow continues to increase, when the pressure of the demineralized water network decreases to the pressure setpoint P1 of the first pressure switch 9, the first pressure switch 9 sends a start signal, which is sent to the second demineralized water pump 4. The second demineralized water pump 4 starts automatically after receiving the start signal.

[0035] When the high-flow-rate demineralized water usage ends, and the pressure of the demineralized water network rises to the pressure setpoint P3 of the third pressure switch 11, the third pressure switch 11 sends a shutdown signal. This shutdown signal is sent to the first demineralized water pump 2 and the second demineralized water pump 4. After receiving the shutdown signal, the first demineralized water pump 2 and the second demineralized water pump 4 automatically shut down and wait to be restarted when the next high-flow-rate water usage occurs.

[0036] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for operating a nuclear island demineralized water system, characterized in that, It comprises a nuclear island demineralized water system, said nuclear island demineralized water system comprises a demineralized water tank (1), a fourth pipe (13) is connected to said demineralized water tank (1), a third valve (8) is arranged on said fourth pipe (13), an outlet (18) of the fourth pipe is connected to a first pipe (14), a first demineralized water pump (2) and a first valve (3) are sequentially arranged on said first pipe (14), an outlet (19) of the first pipe is connected to a fifth pipe (17), and a pressure switch is arranged on said fifth pipe (17); an inlet of a third pipe (16) is connected to said fourth pipe (13) between said third valve (8) and said outlet (18) of the fourth pipe, and an outlet of the third pipe (16) is connected to said fifth pipe (17) between said outlet (19) of the first pipe and said pressure switch; a pressure stabilizing pump (6) and a pressure stabilizing tank (7) are sequentially arranged on said third pipe (16), said pressure switch comprises a first pressure switch (9), a second pressure switch (10), a third pressure switch (11) and a fourth pressure switch (12) which are sequentially arranged, wherein the pressure value P1 of said first pressure switch (9), the pressure value P2 of said second pressure switch (10), the pressure value P3 of said third pressure switch (11) and the pressure value P4 of said fourth pressure switch (12) satisfy the relationship P1<P2<P3<P4; said nuclear island demineralized water system further comprises a second pipe (15), an inlet of said second pipe (15) is connected to said outlet (18) of the fourth pipe, an outlet of the second pipe (15) is connected to said outlet (19) of the first pipe, a second demineralized water pump (4) and a second valve (5) are sequentially arranged on said second pipe (15); said working method comprises the following steps: Said pressure stabilizing pump (6) automatically starts when the pressure of the demineralized water pipe network is lower than the pressure value P3 of the third pressure switch, and automatically stops operating when the pressure of the demineralized water pipe network is higher than the pressure value P4 of the fourth pressure switch; during a period when there is usually no large-flow water consumption, the pressure of the demineralized water pipe network is maintained between said pressure value P3 and said pressure value P4; When the water consumption of the demineralized water pipe network increases and the pressure of the demineralized water pipe network decreases to the pressure value P2 of the second pressure switch, said first demineralized water pump (2) starts; if the flow rate of demineralized water continues to increase and the pressure of the demineralized water pipe network decreases to the pressure value P1 of the first pressure switch, said second demineralized water pump (4) starts; When large-flow demineralized water consumption ends, the pressure of the demineralized water pipe network rises to said pressure value P3, said first demineralized water pump (2) and said second demineralized water pump (4) automatically stop operating, and wait to be started when the next large-flow water consumption occurs.

2. The operating method of the nuclear island demineralized water system according to claim 1, characterized in that, Said pressure stabilizing pump (6) is a variable-frequency pressure stabilizing pump.

3. The operating method of the nuclear island demineralized water system according to claim 1, characterized in that, Said first valve (3) is a stop valve.

4. The operating method of the nuclear island demineralized water system according to claim 1, characterized in that, Said second valve (5) is a stop valve.

5. The operating method of the nuclear island demineralized water system according to claim 1, characterized in that, Said third valve (8) is a stop valve.

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