JP4316457B2 - Method and system for inhibiting the attachment and growth of marine organisms - Google Patents

Description

  The present invention relates to a method and system for suppressing the attachment and growth of marine organisms in a cooling water system for cooling a device such as a condenser using seawater.

In thermal power plants that use seawater as cooling water, shells, etc. are placed inside the intake channel that takes seawater from the ocean and supplies it to the condenser, and discharges the seawater that passes through the condenser to the ocean. The marine life is easy to adhere. When the adhesion amount of such marine organisms increases, there is a risk of causing problems such as blocking the cooling water flow path and lowering the cooling performance. Therefore, conventionally, as disclosed in, for example, Patent Document 1 and Patent Document 2, by injecting a chlorine-based chemical such as sodium hypochlorite solution or chlorine dioxide into the flow path of cooling water, Suppression of the attachment and growth of marine organisms has been carried out.
JP-A-7-265867 JP 11-37666 A

  As mentioned above, seawater after being used as cooling water in thermal power plants is released to the sea, but for environmental conservation, the chlorine concentration (residual chlorine concentration) contained in the discharged water to the sea is constant. It is required to be less than the allowable value (the agreed value of chlorine concentration in seawater that can be released into the sea). Therefore, the injection concentration of chlorinated chemicals for removing marine organisms must also be limited so that the above requirements can be satisfied. Furthermore, in order to remove marine organisms efficiently, it is necessary to maintain a constant chlorine concentration. On the other hand, when the temperature of seawater rises due to changes in temperature, etc., the amount of chlorine decomposed increases and the residual chlorine concentration decreases, so simply injecting a fixed amount of chemical can achieve the expected removal effect. Can not.

  The present invention has been made in view of the above points, and in cooling the facility to be cooled with seawater, the chlorine injection amount is adjusted according to the change in seawater temperature, and the chlorine concentration in the seawater released to the sea It is an object of the present invention to provide a method and system capable of effectively suppressing the attachment and growth of marine organisms while keeping the temperature low.

To achieve the above object, the invention described in claim 1 includes a waterway preparative be supplied to the cooling target facility incorporating seawater from the sea as cooling water, seawater after passing through the cooling target facility to the sea A method for suppressing adhesion and growth of marine organisms in a cooling water flow path having a discharge water discharge path ,
A drug injection part for injecting a chlorinated drug into the intake channel is provided,
Stores data representing changes in drug concentration over time for various temperatures,
The stored data on the temperature of the cooling water in the water discharge channel, and the predetermined allowable value so that the concentration of the drug near the discharge port for discharging the cooling water from the water discharge channel into the sea is equal to or less than a predetermined allowable value. On the basis of the determination of the drug concentration in the facility to be cooled,
Based on the determined drug concentration and the stored data about the temperature of the intake channel, determine the drug concentration in the drug injection part,
Determining the injection amount of the chlorinated drug by the drug injection unit based on the determined drug concentration;
The determined amount of the chlorinated drug is injected into the intake channel by the drug injection unit .

  According to the present invention, the injection concentration of the chlorinated drug is adjusted according to the temperature change of the seawater. For this reason, even if the seawater temperature changes, the chlorine concentration above a certain value can always be maintained, and the adhesion and growth of marine organisms can be effectively suppressed while keeping the chlorine concentration in the seawater released to the sea low. .

  The invention described in claim 2 is characterized in that, in the method described in claim 1, sodium hypochlorite is injected as the chlorinated drug.

Further, the invention described in claim 3, and waterways preparative be supplied to the cooling target facility incorporating seawater from the sea as cooling water, the spillway and which emits seawater after passing through the cooling target facility to the sea A system for suppressing the adhesion and growth of marine organisms in a cooling water flow path having
A drug injection part for injecting a chlorinated drug into the intake channel ;
A temperature detector for detecting the temperature of the cooling water;
A drug injection amount determining unit that determines an amount of a chlorine-based drug to be injected into the intake channel by the drug injection unit according to the detected temperature of the cooling water;
An injection control unit for injecting the determined amount of chlorinated drug by the drug injection unit,
The drug injection amount determination unit has a storage unit that stores data representing changes in drug concentration over time at various temperatures, and the drug concentration near the discharge port that discharges cooling water from the discharge channel into the sea has a predetermined tolerance. A drug concentration in the facility to be cooled is determined based on the stored data on the temperature of the cooling water in the water discharge channel and the predetermined allowable value so as to be equal to or less than a value, and the determined drug concentration , Determining a drug concentration in the drug injection unit based on the stored data on the temperature of the cooling water flow path of the intake channel, and injecting a chlorine-based drug by the drug injection unit based on the determined drug concentration It is characterized by determining the quantity .

  According to the present invention, when cooling the facility to be cooled with seawater, the chlorine injection amount is adjusted according to the change in seawater temperature, and the concentration of chlorine in the seawater released to the sea is kept low, while effectively And a method and system for suppressing the adhesion and growth of the substrate.

  FIG. 1 is a schematic plan view of a thermal power plant 10 according to an embodiment of the present invention. As shown in the figure, the thermal power plant 10 is constructed on a site facing the sea 2. The thermal power plant 10 is provided with various facilities such as a fuel storage facility 12, an LNG tank 14, and a power generation facility 16, for example. In this embodiment, the condenser 18 provided in the power generation facility 16 is cooled with seawater. The intake 20 for taking seawater from the sea 2 and supplying it to the condenser 18, and the condenser 18. A water discharge channel 22 for discharging the seawater that has passed through to the sea 2 is installed. Seawater is taken in from the water intake 24 at the tip of the intake channel 20, flows through the water intake channel 20, passes through the condenser 18, flows through the water discharge channel 22, and is discharged from the water discharge port 26 at the tip thereof to the sea 2. The intake channel 20 and the discharge channel 22 correspond to the “cooling water channel” of the present invention.

  As described above, since seawater flows through the intake channel 20 and the discharge channel 22, marine organisms such as shellfish are easily attached and grown in the channel. If a large amount of marine organisms adhere to the flow path, the flow performance may be reduced because the flow path is blocked and a sufficient flow rate cannot be obtained. In particular, with regard to the intake channel 20, since the intake 24 is provided offshore so as to be able to take in seawater having a low water temperature, the intake channel 20 becomes very long and is affected by the attachment of marine organisms. Cheap.

  Therefore, in this embodiment, by injecting a sodium hypochlorite solution as a chlorinated chemical into the intake channel 20 at a point near the intake port 24 of the intake channel 20, the inner wall surface of the intake channel 20 or the discharge channel 22. Suppresses the adhesion and growth of marine organisms such as shellfish. However, it is not limited to sodium hypochlorite, and other chlorinated chemicals such as chlorine dioxide may be used.

  FIG. 2 is a schematic diagram of a cooling system 28 including a water intake channel 20 and a water discharge channel 22. As shown in the figure, a seawater pump 30 is provided at a connection portion between the condenser 18 and the intake channel 20, and seawater is drawn into the intake channel 20 from the intake port 24 by the seawater pump 30. In addition, a drug injection part 32 is provided in the vicinity of the water intake 24 of the water intake channel 20. The drug injection part 32 may be provided at a plurality of locations along the flow of the intake channel 20. Further, a residual chlorine concentration meter 34 for detecting the residual chlorine concentration in the seawater discharged to the sea 2 is provided in the vicinity of the water outlet 26 of the water discharge channel 22. The detection signal from the residual chlorine concentration meter 34 is sent wirelessly or by wire to a monitoring device provided on land.

  FIG. 3 shows a detailed configuration of the drug injection unit 32. As shown in the figure, the drug injection unit 32 includes a temperature detection unit 45 that measures seawater temperature, a drug injection amount determination unit 43 that calculates an optimal chlorine injection concentration, a storage unit 47 that stores data, A chemical supply device 42 that decomposes and supplies a sodium hypochlorite solution to the injection pipe 40, an injection control unit 46 that controls the chlorine injection concentration, and a valve 44 provided in the injection pipe 40 are configured. The opening / closing of the valve 44 may be controlled by the injection control unit 46. Further, the injection control unit 46 controls the chlorine injection concentration by controlling the current value of the drug supply device 42 with reference to the drug injection concentration determined by the drug injection amount determination unit 43.

  In the example shown in FIG. 3, the tip of the injection tube 40 is bent toward the downstream side of the seawater, and an injection port 41 is provided at the tip. In addition, as shown in FIG. 4, you may comprise so that the cross section of the front-end | tip part of the injection tube 40 may spread toward the injection port 41 gradually. Further, as shown in FIG. 5, a hole provided on the downstream side surface may be used as the injection port 41 without bending the injection tube 40. Thus, various structures can be considered as the injection port 41.

  In addition, the injection pipe 40 shall be arrange | positioned along the both sides | surfaces and upper surface of the cross section of the intake channel 20. FIG. The reason why the water injection pipe 40 is not disposed on the bottom surface of the intake channel 20 is that the sludge accumulates on the bottom of the intake channel 20, so that the sodium hypochlorite solution is injected at a position avoiding this. . A plurality of injection tubes 40 may be provided, and the drug supply device 42 and the injection control unit 46 are provided in common in the drug injection unit 32. Further, the number of the drug injection parts 32 is not particularly limited, and a plurality of drug injection parts 32 may be provided along the flow of the intake channel 20.

  FIG. 6 is a diagram showing an example of changes in residual chlorine concentration over time for seawater with different chlorine injection concentrations. Moreover, FIG. 7 is a figure which shows an example of the change of residual chlorine concentration with progress of time about the seawater from which temperature differs. As shown in these drawings, the residual chlorine concentration in seawater gradually decreases as chlorine decomposes over time.

  The storage unit 47 stores data representing a time variation curve of the residual chlorine concentration as shown in FIGS. 6 and 7 for each temperature and each initial concentration of chlorine. And the chemical | medical agent density | concentration determination part 43 refers to these data, the intake channel 20, and the seawater temperature which flows through the condensate channel 18, so that it may become below an agreement value near the water discharge port 26 so that it may demonstrate below. Determine the chlorine injection concentration. As described above, the residual chlorine concentration in the seawater into which chlorine has been injected shows a change over time according to the seawater temperature. After the chlorinated chemical is injected into the seawater, the time until it is released from the water outlet 26 into the sea is fixed. Therefore, if the seawater temperatures of the intake channel 20 and the discharge channel 22 are known, the chlorine-based chemical injection that makes the residual chlorine concentration at the discharge port 26 equal to or less than the agreed value with reference to the data stored in the storage unit 47. The amount can be determined.

FIG. 8 is a simplified diagram showing the change in seawater temperature from the water intake 24 to the water outlet 26. As shown in the figure, since the seawater temperature rises due to heat exchange with the condenser 18, if the seawater temperature in the intake channel 20 is T ₀ (° C) and the temperature rise width is α (° C), the seawater temperature is released. The seawater temperature of the water channel 22 is expressed as (T ₀ + α) (° C.). The temperature increase width α (° C.) is, for example, α = + 7 (° C.). The seawater temperature in the discharge channel 22 can be obtained from the temperature in the vicinity of the intake port 24 as described above, but may be directly measured.

  Based on the seawater temperatures of the intake channel 20 and the discharge channel 22 determined in this manner, the injection amount of the chlorinated drug by the drug injection unit is determined so that the residual chlorine concentration at the discharge port 26 is not more than the agreed value.

  FIG. 9 is a diagram for explaining the procedure for determining the chlorine injection concentration. As shown in the figure, since the seawater temperature rises before and after the condenser 18, the rate of decrease in the residual chlorine concentration increases with the condenser 18 as a boundary. In such a case, it is necessary to determine the injection amount of the chlorinated chemical in consideration of the temperature change of the seawater around the condenser 18.

The amount of chlorinated chemical injected is, for example, the chlorine concentration in the vicinity of the condenser 18 is obtained from the chlorine concentration in the vicinity of the outlet 26 determined to be equal to or less than the agreed value, and this chlorine concentration in the vicinity of the condenser 18 is calculated. This is determined by determining the chlorine injection concentration. More specifically, the chlorine concentration in the vicinity of the condenser 18 is the seawater temperature (T ₀ + α) in the vicinity of the outlet 26 and the seawater into which the chlorine-based chemical has been injected reaches the outlet 26 from the condenser 18. since the known time required for the (t ₀₎ is a refers to the storage unit 47, when the sea water is time t ₀ has elapsed since passing through the condenser 18, the residual chlorine concentration less agreement value A curve for the seawater temperature (T ₀ + α) is found, and the initial concentration of the curve is determined as the chlorine concentration in the condenser 18. Similarly, regarding the chlorine injection concentration, the seawater temperature (T ₀ ) near the intake port 24 and the time (t ₁ ) required for the seawater into which the chlorine-based chemical has been injected to reach the intake port 24 from the condenser 18 Since the residual chlorine concentration near the condenser 18 becomes equal to the previously obtained chlorine concentration near the condenser 18 when time t _{1 has} elapsed since chlorine injection, the seawater temperature T ₀ And the initial concentration of the curve is determined as the chlorine injection concentration in the drug injection unit 32. Then, based on the chlorine injection concentration, the injection amount of the chlorine-based drug from the drug injection unit 32 is determined.

  Further, in this embodiment, the injection amount of the chlorine-based chemical is determined by using the data of the temporal change of the residual chlorine concentration having different temperature conditions with the condenser 18 as a boundary, but the temperature change in the condenser 18 is determined in advance. May be stored in the storage unit 47, and the drug injection amount may be determined using this data.

  In the above embodiment, the condenser of the thermal power plant is cooled as the equipment to be cooled. However, the present invention is not limited to the condenser and is widely applied when cooling various equipment using seawater. Is possible.

1 is a schematic plan view of a thermal power plant according to an embodiment of the present invention. It is a figure which shows typically the cooling water system | strain which consists of a water intake channel and a water discharge channel. It is a figure which shows the detailed structure of a chemical | medical agent injection | pouring part. It is a figure which shows the structural example of the injection port of an injection tube. It is a figure which shows another structural example of the injection inlet of an injection tube. It is an example of the figure which showed the mode of the change accompanying the time relationship of the residual chlorine concentration of the sodium hypochlorite solution in each injection density | concentration. It is an example of the figure which showed the mode of the change accompanying the temporal relationship of the residual chlorine concentration of the sodium hypochlorite solution in each seawater temperature. It is the figure which simplified and showed the mode of the change of the seawater temperature from a water intake to a water discharge port. It is a figure which simplifies and shows the relationship between the residual chlorine concentration from a water intake to a water discharge port, and decomposition | disassembly time.

Explanation of symbols

2 Sea 10 Thermal Power Plant 12 Fuel Storage Facility 14 LNG Tank 16 Power Generation Facility 18 Condenser 20 Intake Channel 22 Discharge Channel 24 Intake 26 Outlet 28 Cooling Water System 30 Seawater Pump 32 Drug Injection Unit 34 Residual Chlorine Concentration Meter 40 Injection Pipe 41 Inlet 42 Drug supply device 43 Drug injection amount determination unit 44 Valve 45 Temperature detection unit 46 Injection control unit 47 Storage unit

Claims (3)

And waterways preparative be supplied to the cooling target facility incorporating seawater from the sea as cooling water, the cooling to target release seawater after passing through the equipment to the sea spillway and attachment and growth of marine organisms in the cooling water channel having a A method of suppressing
A drug injection part for injecting a chlorinated drug into the intake channel is provided,
Stores data representing changes in drug concentration over time for various temperatures,
The stored data on the temperature of the cooling water in the water discharge channel, and the predetermined allowable value so that the concentration of the drug near the discharge port for discharging the cooling water from the water discharge channel into the sea is equal to or less than a predetermined allowable value. On the basis of the determination of the drug concentration in the facility to be cooled,
Based on the determined drug concentration and the stored data about the temperature of the intake channel, determine the drug concentration in the drug injection part,
Determining the injection amount of the chlorinated drug by the drug injection unit based on the determined drug concentration;
A method of injecting the determined amount of the chlorinated drug into the intake channel by the drug injection unit .   The method according to claim 1, wherein sodium hypochlorite is injected as the chlorinated drug. And waterways preparative be supplied to the cooling target facility incorporating seawater from the sea as cooling water, the cooling to target release seawater after passing through the equipment to the sea spillway and attachment and growth of marine organisms in the cooling water channel having a A system for suppressing
A drug injection part for injecting a chlorinated drug into the intake channel ;
A temperature detector for detecting the temperature of the cooling water;
A drug injection amount determining unit that determines an amount of a chlorine-based drug to be injected into the intake channel by the drug injection unit according to the detected temperature of the cooling water;
An injection control unit for injecting the determined amount of chlorinated drug by the drug injection unit,
The drug injection amount determination unit has a storage unit that stores data representing changes in drug concentration over time at various temperatures, and the drug concentration near the discharge port that discharges cooling water from the discharge channel into the sea has a predetermined tolerance. A drug concentration in the facility to be cooled is determined based on the stored data on the temperature of the cooling water in the water discharge channel and the predetermined allowable value so as to be equal to or less than a value, and the determined drug concentration , Determining a drug concentration in the drug injection unit based on the stored data on the temperature of the cooling water flow path of the intake channel, and injecting a chlorine-based drug by the drug injection unit based on the determined drug concentration A system characterized by determining the quantity .

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