JP2005144212A - Method and system for controlling adhesion and growth of marine organism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the concentration of chlorine in seawater discharged into sea at low level while effectively controlling the adhesion and growth of marine organisms, such as shellfishes, adhering to the passage composing a cooling water system with a chlorine-based chemical when cooling target equipment with seawater. <P>SOLUTION: A chemical injection part 32 is installed in the vicinity of the water intake port 24 of a water intake passage 20 supplying seawater to a steam condenser in a thermal power plant as cooling water. The chemical injection part 32 is composed of an injection pipe 40 having an inlet 41 in the water intake passage 20, a chemical supply tank 42 for supplying a sodium hypochlorite solution to the injection pipe 40, and a valve 44 installed in the injection pipe 40. The opening and closing of the valve 44 is controlled by a control device 46. By opening and closing the valve 44 with the control device 46, the sodium hypochlorite solution is injected intermittently. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and a system for suppressing adhesion and growth of marine organisms in a cooling water flow path for supplying seawater as cooling water to a cooling target facility such as a condenser of a thermal power plant.

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 the discharge channel that releases the seawater that has passed 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 Japanese Patent Laid-Open No. 11-37666

  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 below the agreed value. Therefore, the injection amount of the chlorinated chemical for removing marine organisms must be limited so as to satisfy the above requirements, and it is not easy to obtain a sufficient removal effect within the limits.

  The present invention has been made in view of the above points, and when cooling a facility to be cooled with seawater, the adhesion and growth of marine organisms are effectively suppressed with a chlorine-based chemical in the cooling water flow path, while entering the sea. The purpose is to make it possible to keep the chlorine concentration in the released seawater low.

  In order to achieve the above object, the invention described in claim 1 is for taking seawater from the sea as cooling water and supplying it to the facility to be cooled, and discharging the seawater after passing through the facility to be cooled to the sea. This is a method for suppressing the adhesion and growth of marine organisms in the cooling water flow path, characterized by intermittently injecting a chlorine-based chemical into the cooling water flow path.

  According to the present invention, since the chlorine-based chemical is injected intermittently, the residual chlorine concentration at the injection position changes in a pulse shape. This chlorine concentration is gradually leveled as the cooling water flows downstream, and the residual chlorine concentration at the discharge position to the sea becomes a substantially constant small value. Therefore, according to the present invention, the residual chlorine concentration in the seawater released to the sea is secured while ensuring a large peak value of the residual chlorine concentration in the cooling water flow path and effectively suppressing the adhesion and growth of marine organisms. Can be kept low.

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

The invention described in claim 3 is a system that suppresses the adhesion and growth of marine organisms in a cooling water flow path for supplying seawater as cooling water to a facility to be cooled,
An injection tube for injecting a chlorine-based chemical into the cooling water flow path;
An on-off valve provided in the injection pipe;
And a control means for intermittently opening and closing the opening / closing valve.

  According to the present invention, when cooling a facility to be cooled with seawater, while the adhesion and growth of shellfish and other marine organisms are effectively suppressed with a chlorine-based chemical in the cooling water flow path, Chlorine concentration can be kept low.

  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. 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 intake port 24 at the tip of the intake channel 20, flows through the intake channel 20, passes through the condenser 18, flows through the discharge channel 22, and is discharged from the discharge port 26 at the tip of the intake channel 20. 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 propagated 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 far away from the land so that low temperature seawater can be taken in, the intake channel 20 becomes very long and is affected by the attachment of marine organisms. easy.

  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 schematically shows a cooling water 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. A drug injection part 32 is provided in the vicinity of the water intake 24 of the water intake path 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 section 32 includes an injection pipe 40 having an injection port 41 inside the intake channel 20, a drug supply tank 42 for supplying a sodium hypochlorite solution to the injection pipe 40, and an injection pipe 40. The opening and closing of the valve 44 is controlled by a control device 46. 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.

  The injection pipe 40 is preferably attached along the wall surface so that the residual chlorine concentration in the vicinity of the wall surface of the intake channel 20 is high. In that case, since sludge accumulates in the bottom part of the intake channel 20, it shall be attached along the wall surface of a side part or an upper part. A plurality of injection tubes 40 may be provided.

FIG. 6 shows the open / close state of the valve 44 controlled by the control device 46 (that is, the time change of on / off of the drug injection) (FIG. 6A) and the respective parts (intake water) of the cooling water system 26 corresponding thereto. The time change (the figure (b)-(d)) of the residual chlorine concentration in the mouth 24, the condenser 18, and the water discharge port 26) is shown. In the figure (b) ~ (d), the residual chlorine concentration M ₀ represents the allowable value of the residual chlorine concentration in the waste water to seawater (agreement value).

As shown in FIG. 6 (a), the control device 46 opens and closes the valve 44 intermittently, and accordingly, as shown in FIG. 6 (b), the chlorine concentration at the intake port 24 changes in a pulse shape. ing. Moreover, as shown in the figure (c), in the condenser 18, the chlorine concentration waveform becomes a dull waveform from the pulse waveform, and further, when reaching the outlet 26 as shown in the figure (d), the chlorine concentration waveform has a low level of less than agreement value M ₀ is substantially leveled.

  Thus, in this embodiment, the peak value of the chlorine concentration in the intake channel 20 and the discharge channel 22 is increased by intermittently injecting the sodium hypochlorite solution in a pulsed manner by opening and closing the valve 44. However, the residual chlorine concentration in the seawater discharged from the discharge port 26 to the sea 2 can be kept low. The effect of suppressing the attachment and growth of marine organisms such as shellfish by sodium hypochlorite solution depends on the peak value of residual chlorine concentration, and the larger the peak value, the more effectively the attachment and growth of marine organisms is suppressed. be able to. Therefore, in this embodiment, marine organisms such as shellfish attached to the intake channel 20 and the discharge channel 22 can be effectively removed while suppressing the residual chlorine concentration contained in the seawater released into the sea. In particular, since the peak value of the residual chlorine concentration in the intake channel 20 can be increased, marine organisms in the intake channel 20 that are easily affected by the attachment of marine organisms as described above can be effectively removed.

  Since the optimal opening / closing time interval of the valve 44 varies depending on the configuration of the cooling water system 28, the time interval at which marine organisms can be effectively removed is experimentally determined.

  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 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. Open / close state of a valve provided in the injection pipe (change in time of on / off of drug injection) (a) and the change in chlorine concentration in each part of the cooling water system corresponding thereto (figure (b) to ( It is a figure which shows d)).

Explanation of symbols

2 Sea 10 Thermal Power Plant 18 Condenser 20 Intake Channel 22 Discharge Channel 24 Intake 26 Outlet 28 Cooling Water System 30 Seawater Pump 32 Drug Injection Portion 40 Injection Pipe 41 Inlet 42 Drug Supply Tank 44 Valve 46 Control Device

Claims (3)

  This is a method for suppressing the adhesion and growth of marine organisms in the cooling water flow path for taking seawater from the sea as the cooling water and supplying it to the equipment to be cooled, and discharging the seawater that has passed through this equipment to the sea. And a method of intermittently injecting a chlorine-based chemical into the cooling water flow path.   The method according to claim 1, wherein sodium hypochlorite is injected as the chlorinated drug. It is a system that suppresses the adhesion and growth of marine organisms in the cooling water flow path for taking seawater from the sea as the cooling water and supplying it to the equipment to be cooled and discharging the seawater that has passed through this equipment to the sea. And
An injection tube for injecting a chlorine-based chemical into the cooling water flow path;
An on-off valve provided in the injection pipe;
And a control means for intermittently opening and closing the open / close valve.

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