JP4409416B2 - Method for controlling attached organisms in cooling water coolers in power plants - Google Patents

Description

  The present invention relates to a method for controlling attached organisms in a power plant cooling water cooler. More specifically, the present invention relates to a method for suppressing and controlling the growth of marine organisms such as mussels that have an adverse effect when adhering to an indoor cooling water cooler such as a thermal power plant.

  For example, if marine organisms such as mussels that are harmful to these plants adhere to the in-house cooling water cooler in a thermal power plant, the thin tube of the in-house cooling water cooler is blocked to reduce the cooling performance. May have effects or problems. Conventionally, as a countermeasure against attached organisms in an in-house cooling water cooler, a chemical method in which chlorine is injected and directly treated by poisoning is performed in many power plants (for example, see Non-Patent Document 1). ).

Japan Society of Electrochemistry Marine Life Pollution Countermeasures Meeting, “Marine Life Pollution Control Manual”, Gihodo Publishing Co., Ltd., March 8, 1991, pp.106-110

  However, in consideration of the environment, the chlorine injection concentration must be kept low, and the residual chlorine concentration that can sufficiently control the attached organisms in the in-house cooling water cooler may not be maintained. In such a case, the cooling performance of the on-site cooling water cooler is deteriorated particularly at a high water temperature in summer, and as a result, the operation of the power plant may be hindered.

  Accordingly, the present invention provides an attached organism of a power plant cooling water cooler that can effectively control marine organisms such as mussels adhering to a cooling water cooler in a thermal power plant or the like without using chlorine or the like. It aims at providing the control method.

  In order to achieve this object, the present inventor has conducted various studies. Many in-house cooling water coolers in a power plant allow heat exchange with seawater in order to cool the in-house cooling water. At this time, marine organisms have entered and adhered to the in-house cooling water cooler through the seawater conduit used for heat exchange. The inventor can take a structure in which even marine organisms are taken in because of heat exchange with seawater in this way, and can effectively control marine organisms using this structure. I thought of that.

  The present invention is based on such knowledge, and the attached organism control method for a cooling water cooler in a power plant according to claim 1 is a seawater which cools the cooling water in the power plant by flowing through the cooling water cooler in the power plant. Is temporarily stopped and retained in the in-house cooling water cooler, while the in-house cooling water continues to flow continuously or intermittently and the heat of the in-house cooling water is stored in the in-house cooling water cooler. It is given to the water staying in the water, and the temperature of the water is raised to degenerate marine organisms adhering to the inside of the in-house cooling water cooler.

  In the present invention, an environment in which marine organisms entering the power plant cooling water cooler and adhering to the inside can be weakened is easily created. That is, while the flow of the cooling seawater is stopped and retained in the in-house cooling water cooler, the in-house cooling water continues to flow as it is, so that the heat held by the in-house cooling water is continuously given to the seawater. In this case, the heat held by the in-house cooling water is a part of the heat generated in the station during power generation, and it is not necessary to prepare another heat source as long as this heat is used. When this state is maintained for a period of, for example, 1 week to 2 weeks, the staying seawater receives heat and the water temperature rises, creating an environment in which adhering marine organisms are debilitated and eventually drowned.

  In this case, as described in claim 2, it is also preferable that the seawater flowing through the in-house cooling water cooler is temporarily stopped, and then the seawater is replaced with freshwater, and then the freshwater is heated to raise the temperature. . Needless to say, freshwater is not a suitable environment for marine life, so it is possible to create an environment in which attached marine life is further debilitated or drowned.

  According to the method for controlling attached organisms in the power plant cooling water cooler according to claim 1, the temperature of the accumulated seawater in the site cooling water cooler is raised, the marine organisms are weakened or drowned, and the cooling water in the plant is cooled. The inside of the vessel can be maintained in a clean state, and this can prevent the narrow tube of the on-site cooling water cooler from being blocked, thereby preventing the cooling performance of the on-site cooling water at the power plant from being deteriorated. . Therefore, it is possible to continue to operate in a stable state without affecting or affecting the stable operation of the power plant. In addition, it is possible to effectively prevent the heat transfer performance of the on-site cooling water cooler from being reduced, or to recover from the deteriorated state after adhering, so sufficient heat exchange between the on-site cooling water and seawater Can be maintained.

  In addition, the heat used in this case is originally stored in the in-house cooling water at the power plant, so there is no need for a separate heat source to heat the staying seawater. It is also suitable from the viewpoint. In addition, because of the property of using the heat held by the on-site cooling water to raise the temperature of the accumulated seawater, it is possible to control marine organisms without stopping power generation, so there is no significant impact on power generation itself. It is also advantageous in that it can be implemented.

  In addition, it can be said that the attached organism control method according to the present invention is a very suitable method when applied to a cooling water cooler in a power plant. That is, this control method pays attention to the structure in which heat is exchanged with seawater in order to cool the in-house cooling water, and the seawater may be retained in the in-house cooling water cooler for a predetermined period. Therefore, it can be carried out as it is in an existing power plant, or it can be carried out by providing a valve or the like in the seawater conduit, and it is possible to control attached organisms in the cooling water cooler in the power plant. It is suitable for.

  In addition, since it is not necessary to inject chlorine as in the prior art in carrying out the present invention, it can be said that this is a very suitable method for controlling attached organisms in terms of environmental considerations. In particular, since it is a highly safe method for marine organisms such as seafood in the sea area around the power plant, it is a control method having high value from the viewpoint of environmental conservation.

  Further, according to the method for controlling attached organisms according to claim 2, marine organisms are further weakened in combination with the fresh water environment, and the control treatment can be completed in a shorter period of time.

  Hereinafter, the configuration of the present invention will be described in detail based on embodiments shown in the drawings.

  FIG. 6 shows an embodiment of the present invention. The attached organism control method of the power plant cooling water cooler (indicated by reference numeral 1 in FIGS. 6 to 8) according to the present invention is a seawater that flows through the power plant cooling water cooler 1 and cools the site cooling water. Is temporarily stopped and retained in the in-house cooling water cooler 1, while the in-house cooling water continues to flow continuously or intermittently and the heat of the in-house cooling water is retained in the in-house cooling water cooler 1 It is given to the water staying inside, and the temperature of the said water is raised, and marine organisms adhering to the inside of the in-house cooling water cooler 1 are debilitated.

  In many cases, seawater is used to remove heat from the on-site cooling water in the power station and cool it. Seawater is supplied to the seawater supply pipe (seawater pipe 22 that is a conduit for seawater, especially in the on-site cooling water cooler 1. A marine organism such as blue mussel may adhere to the in-house cooling water cooler 1 through the pipe of the portion to be supplied (indicated by reference numeral 22a). In this embodiment, cooling in the in-house cooling water cooler 1 is performed. We try to control attached organisms by a method that focuses on the structure. That is, the valve of the above-mentioned water supply pipe 22a and drainage pipe (referred to as the pipe of the seawater pipe 22 that discharges seawater from the in-house cooling water cooler 1 in particular, indicated by reference numeral 22b) is closed, In FIG. 6, seawater is temporarily retained (see FIGS. 6 to 8). The valve is, for example, a manual valve indicated by reference numeral 4 in FIG. On the other hand, the in-house cooling water continues to flow, and the heat of the in-house cooling water is transferred to seawater by the heat exchanger in the in-house cooling water cooler 1 and given. In such a case, marine organisms that exist by adhering to the tubules in the seawater are drowned, or at least weakened, and their growth is suppressed as the water temperature of the seawater staying rises. In other words, hot water treatment can be performed. In this case, the in-house cooling water may flow continuously, for example, at a substantially constant flow rate, or may flow intermittently instead of being constant. In short, the heat of the seawater is given to at least a certain temperature. Anything can be used as long as it can be raised. Needless to say, a certain temperature in this case is at least a temperature at which marine organisms can be weakened, and the specific numerical value varies depending on the type of marine organisms.

  Here, the outline in the power plant will be described, and the on-site cooling water cooler 1 will also be described (see FIG. 9). First, the cooling water system 10 in the power plant will be described. In addition to the in-house cooling water pipe 11, the cooling water system 10 is provided with a stand pipe 12, a cooling water pump 13, and operation valves 14 and 15. The in-house cooling water after cooling is sent to the cooling water system 10 at a return temperature of about 33 to 35 ° C., for example. The stand pipe 12 is a high-pressure pipe attached in a yagura. The stand pipe 12 has a height of, for example, about 20 m, and is filled with indoor cooling water with the atmosphere open, and serves to keep the inlet pressure of the internal cooling water pump constant. When a hole is opened in the in-house cooling water narrow tube 8 and the cooling water leaks and the cooling water amount decreases, water is replenished from the stand pipe 12 to compensate for the lack of cooling water and raise the lowered water level. Water is added to this pipe to keep the cooling water amount constant.

  After being sent to the cooling water system 10, the in-house cooling water is pressurized by, for example, three cooling water pumps 13 arranged in parallel, and sent to one of the three in-house cooling water coolers 1. In FIG. 9, the three on-site cooling water coolers 1 provided in the power plant are indicated as an A-site cooling cooler, a B-site cooling cooler, and a C-site cooling cooler for convenience (FIG. 9). reference). The in-house cooling water cooled by any of the three in-house cooling water coolers 1 passes through the in-house cooling water pipe 11 again, passes through the operation valves 14 and 15, and then is installed in a device in the power station (for example, a hydrogen cooler, oil Cooler, auxiliary machine bearings, etc.) (see FIG. 9).

  The seawater system 20 in the power plant is as follows. That is, the seawater system 20 of the present embodiment includes a circulating water pump 21, a seawater pipe 22, a seawater booster pump 23, a water chamber 24 of the condenser A, a water chamber 25 of the condenser B, a valve 26, and a collector. 27 is provided. Most of the seawater pressurized by the circulating water pump 21 and sent through the seawater pipe 22 is sent to the system with the condenser and the collector 27, and the remaining part is the system with the in-house cooling water cooler 1. (See FIG. 9). Seawater sent to the system with the condenser and the collector 27 passes through one of the condenser A water chamber 24 and the condenser B water chamber 25, passes through the collector 27, Returned to the sea. In this case, which condenser water chamber the seawater passes depends on the combination of opening and closing of a plurality of valves 26 provided in the middle of the seawater pipe 22. On the other hand, the seawater sent to the system with the in-house cooling water cooler 1 is pressurized by, for example, three parallel seawater booster pumps 23, and there are three in-house cooling water coolers (A-cooling cooler, B 1 place cooling cooler, C place cooling cooler) 1 is sent. The seawater that has been subjected to heat exchange in the in-house cooling water cooler 1 and has cooled the in-house cooling water is sent to the seawater pipe 22 past the collector 27 and merges with the seawater sent to the condenser side. .

  Next, the in-house cooling water cooler 1 in the power plant will be described. The in-house cooling water cooler 1 of the present embodiment is, for example, in a steam condenser for rotating a turbine, and the in-house cooling in a high temperature state. It is a device that exchanges heat between water (in this example, water supply or steam thereof) and seawater. As an example of the control treatment, for example, the seawater in the in-house cooling water cooler 1 is temporarily stopped and retained in accordance with the time when the mussel, which is the main attached organism, attaches and grows, and the heat from the in-house cooling water is By continuing to give to this stagnant seawater, attached organisms are weakened, growth is suppressed or prevented, and eventually drowned, and the inside cooling water cooler 1 is maintained in a clean state.

  The in-house cooling water cooler 1 of the present embodiment has a vertically long cylindrical shape as shown in FIG. 10, and an upper tube plate 3 is provided therein, and sea water is provided between the upper tube plate 3 and the lid portion 2. A space through which is passed is formed. Further, this space is partitioned almost in half by a partition plate 4 and divided into a supply-side chamber S1 into which seawater is fed and a discharge-side chamber S3 through which seawater is sent out. The water supply pipe 22a described above is connected to the supply-side chamber S1, and the drain pipe 22b is connected to the discharge-side chamber S3. A seawater inlet valve 26a is provided in the middle of the water supply pipe 22a, and a seawater outlet valve 26b is provided in the middle of the drainage pipe 22b (see FIG. 11 and the like). The upper lid 2 is provided with an air vent valve (vent vent port) 5 for each of the supply-side chamber S1 and the discharge-side chamber S3 (see FIGS. 7 and 10). A lower tube plate 6 having the same shape as the above-described upper tube plate 3 is provided at the lower part of the in-house cooling water cooler 1. The upper tube plate 3 and the lower tube plate 6 are provided with many small holes 7, and a plurality of thin tubes 8 that vertically connect the upper and lower small holes 7 are provided in the in-house cooling water cooler 1. ing. Between the bottom of the in-house cooling water cooler 1 and the lower tube plate 6 is an intermediate chamber S2 in which seawater turns back when passing through the narrow tube 8. In addition, in FIG. 10, the barnacle adhering to the lower tube board 6 and the blue mussel adhering to the bottom part of a room | chamber are shown as a specific example of the marine organism adhering in this intermediate chamber S2 (refer FIG. 10). In the on-site cooling water cooler 1 of the present embodiment configured as described above, the water supply passage 22a → the supply side chamber S1 → the narrow tube 8 → the intermediate chamber S2 → the narrow tube 8 → the discharge side chamber is used as the seawater passage. A path of S3 → drain pipe 22b is formed. As shown in FIG. 10, a hand hole 9 through which a worker can insert his hand during maintenance or the like and a detachable lid for closing the hand hole 9 are provided at the bottom of the in-house cooling water cooler 1. It has been. Further, a blow valve 16 for discharging seawater from the bottom is provided at the bottom center (see FIG. 8 and the like).

  Further, a side portion of the in-house cooling water cooler 1 and below the upper tube plate 3 is provided with an in-house cooling water supply pipe (in particular, the in-house cooling water pipe 11 of the in-house cooling water pipe 11 which is a pipe for in-house cooling water). The pipe of the part which supplies a site | part cooling water to the water cooler 1 is shown, and it shows by the code | symbol 11a) (refer FIG. 10). Further, a side of the in-house cooling water cooler 1 and above the lower tube plate 6 has an in-house cooling water drain pipe (in particular, the in-house cooling water pipe 11, the in-house cooling water cooler 1 to the in-house cooling water. Is connected to the pipe of the portion that discharges the gas and is indicated by reference numeral 11b. An in-house cooling water inlet valve 14a is provided in the middle of the water supply pipe 11a, and an in-house cooling water outlet valve 14b is provided in the middle of the drain pipe 11b (see FIG. 11 and the like). As described above, in this in-house cooling water cooler 1, the in-house cooling water flowing from the water supply pipe 11a flows in the space around the narrow pipe 8 and is discharged from the drain pipe 11b. As described above, when the seawater flows inside the narrow tube 8 and the in-house cooling water flows outside (surrounding), heat exchange is performed between these two fluids, and the temperature of the in-house cooling water decreases.

  Subsequently, as a control method for degrading marine organisms adhering to the in-house cooling water cooler 1 and eventually leading to drowning, the sea water is temporarily stopped, and the heat held by the in-house cooling water is applied to the sea water. The process procedure (warm water treatment procedure) of raising the temperature will be described (see FIGS. 11 and 12). Here, first, whether one of the on-site cooling water coolers (indicated as “station cooling cooler” in FIG. 12) 1 can be reserved (that is, for example, two of the three on-site cooling units) In the following, it is confirmed whether or not sufficient cooling capacity can be ensured (step 1). That is, first, the in-house cooling water outlet valve 14b is closed (step 2), the seawater outlet valve 26b is closed (step 3), and the seawater inlet valve 26a is further closed (step 4). After the cooling water outlet valve 14b is closed, the cooling water outlet valve 14b is slightly opened so that the in-house cooling water flows little by little, and thereby heat is given to the accumulated seawater in the in-house cooling water cooler 1. . In this case, it is desirable to reduce the flow rate because there is a possibility that the temperature of the in-house cooling water will not drop if too much in-house cooling water is flowed. The air vent valve 5 is kept open (step 5). In this state, seawater stays in the supply-side chamber S1, the intermediate chamber S2, the discharge-side chamber S3, and the narrow tube 8, and in this state, the heat held by the in-house cooling water is given. The temperature rises. For example, in this embodiment, it is allowed to stand for 5 hours or more in this state (step 6), and after degrading marine organisms adhering to the inside of the in-house cooling water cooler 1, the blow valve 16 is opened and the inside Seawater is discharged from the bottom of the cooling water cooler 1 (step 7). By opening the blow valve 16 in this way, marine organisms that are weakened or drowned are discharged together with seawater into the drainage channel. Thereafter, the blow valve 16 is closed (step 8), the seawater inlet valve 26a is opened, and the seawater is once again filled in the in-house cooling water cooler 1 (step 9), and the in-house cooling water inlet valve 14a and the in-house cooling are performed. Both of the water outlet valves 14b are opened to pass the in-house cooling water (step 10).

  It should be noted that marine organisms that have been weakened or drowned, such as those with small shells, are peeled off from the tube wall and tube plates 3 and 6 of the narrow tube 8 and then discharged to the outside through the narrow tube. Is done. On the other hand, marine organisms of a size that does not pass through the narrow tube are washed out by operating the valve 26 and backflowing the seawater (this is referred to as “backwashing” in this specification). It is possible to discharge outside. That is, as shown in FIG. 10, if the water flow is reversed and backwashing is performed, the seawater is drained pipe 22b → discharge side chamber S3 → thin tube 8 → intermediate chamber S2 → thin tube 8 → supply side chamber S1. → The water supply pipe 22a flows in the opposite direction as before, and is a marine organism having a size that does not pass through the narrow tube 8 (for example, cannot pass through the narrow tube 8 and adheres to the inside of the supply-side chamber S1. The mussel that has been used can be discharged to the outside of the on-site cooling water cooler 1.

  In addition, in terms of creating an environment in which marine organisms adhering to the in-house cooling water cooler 1 are weakened and eventually drowned, the sea water in the in-house cooling water cooler 1 is stopped, and then this sea water is made into fresh water. It is also effective to replace In such a case, fresh water stays in the in-house cooling water cooler 1, and the osmotic pressure changes greatly. In this way, fresh water treatment can be applied to create an environment that can deplete marine life and suppress its growth, and in some cases, to drown. In the following, as another control method for degrading marine organisms adhering to the in-house cooling water cooler 1 and eventually leading to drowning, the seawater is temporarily stopped and then replaced with fresh water ( The fresh water replacement procedure will be described (see FIGS. 13 and 14).

  Here, first, the in-house cooling water outlet valve 14b of the in-house cooling water cooler (indicated as “cooling air cooler” in FIG. 14) 1 is closed (step 11), and the seawater outlet valve 26b is closed (step 12). Further, the seawater inlet valve 26a is closed (step 13). The air vent valve 5 is kept open (step 14). Subsequently, the seawater blow valve 16 is opened in this state, and the seawater in the in-house cooling water cooler 1 is extracted from the bottom (step 15). After about 15 minutes, when the seawater is extracted (step 16), the blow valve 16 is closed (step 17), and the seawater-side fresh water inlet valve is opened (step 18). The seawater-side freshwater inlet valve is not particularly shown in the figure, but is provided, for example, in the middle of the seawater drain pipe 22b. By opening this valve, the supply-side chamber S1, the narrow tube 8, and the intermediate chamber S2 Fresh water can be introduced into the discharge-side chamber S3 and the like. For example, in the case of this embodiment, since it can be filled with fresh water after about 65 minutes have passed (step 19), the seawater side fresh water inlet valve is closed when the water is full (step 20). After that, it is only necessary to carry out a control process that keeps this state for a predetermined time to weaken the marine organisms and eventually cause drowning.

  Needless to say, if the above control methods are combined, the attached organisms can be controlled more effectively. That is, if the seawater in the in-house cooling water cooler 1 is replaced with fresh water and then the temperature is increased by applying heat to the fresh water, the attached organism is further combined with the fresh water and the high water temperature. It is possible to effectively weaken or cause drowning, and control processing in a short period of time becomes possible.

  The control method of the present embodiment described above is suitable when, for example, a plurality of on-site cooling water coolers 1 are provided for a turbine power generation device. In other words, it is possible to carry out the control treatment in the in-house cooling water cooler 1 in a portion with a margin while ensuring the necessary minimum cooling capacity in the power generating device. In such a case, it is necessary to stop the operation of the power generating device. In addition, since it is possible to raise the water temperature of the accumulated seawater by using heat generated during operation, it is possible to realize high efficiency as the entire apparatus.

  According to the control method described above, marine organisms attached to the in-house cooling water cooler 1 can be killed and exterminated, or at least debilitated to suppress their growth. In such a case, since it is possible to prevent the narrow tube of the in-house cooling water cooler 1 from being blocked, it is possible to prevent the cooling performance of the in-house cooling water in the power plant from being deteriorated. Therefore, it is possible to operate stably without affecting or operating the power plant.

  Moreover, as is clear from the above description, when the stagnant water (seawater or fresh water) is heated, the heat in the in-house cooling water cooler 1, more specifically, the in-house cooling water has. The remaining water temperature is merely increased using the heat that is present, and no other heat source or the like is required. Further, a mechanism required for temporarily retaining seawater in the seawater supply / discharge pipes 2 and 3 is a manual valve provided in the middle thereof, and no special mechanism is required (see FIG. 6). Therefore, the control method according to the present embodiment is suitable from the viewpoint of effective use of thermal energy and simplification and miniaturization of the apparatus.

  In addition, since no chlorine is used in the prior art to control marine organisms, it is environmentally friendly, and there is no need to consider keeping the chlorine injection concentration low.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, as an example of the timing of performing the control treatment, it has been described that the control is performed in accordance with the timing when the blue mussel adheres and grows. However, the timing of performing this attached organism control method is not particularly limited and is not necessary. Can be done at any time. However, from spring to summer, marine organisms such as mussels that are subject to control are growing, and it is thought that there will be more opportunities for control. Also, as the demand for electricity increases and the temperature of the on-site cooling water rises and high cooling capacity is required, it is also the period when the margin of cooling capacity is the smallest. It may be necessary to eliminate the adverse effects on the cooler 1. Or it can be said that it is effective to carry out control at an early stage by controlling these marine organisms in a small winter season. In any case, the control treatment can be carried out regularly from the viewpoint of maintaining a clean state, and depending on each element such as the structure of the power plant and the on-site cooling water cooler 1, the power generation capacity, the equipment scale, etc. It is also possible to implement it when necessary.

  The inventor actually controlled the organisms attached to the power plant cooling water cooler 1 under various conditions. The contents will be described below as an example. Here, in order to suppress the growth of marine organisms that inhabit the in-house cooling water cooler 1 of the power plant, the control treatment was performed while examining measures such as hot water treatment. The power plant subjected to the control treatment has a structure having three on-site cooling water coolers 1, and these cooling water coolers 1 were regularly observed.

1. Examination of hot water treatment When the inflow of seawater that cools the on-site cooling water cooler 1 is stopped during a weekend break of WSS (meaning operation to stop power generation at the weekend and resume power generation at the beginning of the week) Seawater temperature in the in-house cooling water cooler 1 rises due to the heat of the water. We examined hot water treatment to treat attached organisms using this water temperature rise.

(1) Laboratory experiment on temperature resistance of blue mussels In the experiment, mussel mussels with a shell length of 6 ± 1 mm were used. 100 mL of seawater was placed in a 100 mL beaker, and the water temperature in the beaker was maintained at three stages of 30 ° C., 32 ° C., and 35 ° C. in three constant temperature water baths. The fluctuation range of the water temperature was within ± 0.5 ° C. Ten mussels are placed in each beaker and exposed to the above water temperature for a predetermined period of time. Then, the mussels are transferred into seawater in a 2 L beaker at room temperature (22 ° C.) and observed daily for life and death, and the dead individuals are removed. It was. Two beakers were used in one experimental group, and the mortality rate was calculated from the life and death of 20 mussels in total. Aeration was performed in the seawater of a 2 L beaker and the water was changed every day after observation.

  Table 1 below shows the experimental results regarding the temperature resistance of blue mussels. When the seawater temperature was 35 ° C., the result was that the mortality rate was 100% in 4.25 hours (4 hours and 15 minutes). When the seawater temperature was 32 ° C, the mortality rate was 100% in 17 hours. On the other hand, at 30 ° C., the mortality rate was as low as 44% even after 24 hours. From the above, it has been found that the temperature during the hot water treatment preferably exceeds 30 ° C., more preferably 35 ° C. or higher, resulting in a high numerical mortality rate.

(2) Temperature of the in-house cooling water cooler 1 According to the temperature data of the in-house cooling water at the power station, the water temperature suitable for the treatment when using hot water as a countermeasure against the attached organism of the in-house cooling water cooler 1 is 30 ° C. In the summer, cooling seawater of 30 ° C. or higher can be obtained in the in-house cooling water cooling system, but this cannot be obtained in the April-June period when the main mussels adhere and grow. (See FIGS. 1 to 3).

2. Examination of fresh water treatment If the method is to replace the sea water in the in-house cooling water cooler 1 with fresh water, or to drain the sea water in the in-house cooling water cooler 1 and dry it once a month in the period from April to June It was thought that the growth of attached organisms could be suppressed by the treatment (see FIG. 5). Therefore, the following experiments and observations were performed.

(1) Fresh water treatment method and results First, it is a method, but one of the in-plant cooling water coolers 1 (three units) of the power station No. 1 (Cool A cooler) is treated with fresh water to cool the in-house cooling water. The state of adhesion in the vessel 1 was regularly observed. Moreover, the C place cooler was selected as a comparison object as an in-house cooling water cooler 1 that performs normal seawater flow. The fresh water treatment was carried out once a month for 7 to 15 days in the period from April to June of 2003. The schedule of fresh water treatment and inspection observation is shown in FIG. Moreover, the external appearance of the in-house cooling water cooler 1 is shown in FIGS. Observation, photography, and measurement of blue mussels collected from the in-house cooling water cooler 1 were performed. In addition, the processing procedure of the fresh water replacement here is to perform the internal inspection by alternately repeating the sea water flow and fresh water replacement for the A place cooling cooler, and the C place cooling cooler to be compared as normal sea water passage. , Was the main focus. In addition, the inspection was performed by opening the hand hole 9 below the in-house cooling water cooler (cooler) 1 and visually observing it.

The results of the above experiment and periodic observation (observation on each inspection day on April 18, May 29, and June 30 as shown below) were as follows.
(i) Inspection on April 18 Photographs were taken during the internal inspection after replacement of fresh water on April 3-18. The adhesion state in the in-house cooling water cooler 1 is shown in FIGS. In the experimental area treated with fresh water (hereinafter referred to as “fresh water treatment area”), slime adhering to the thin tubes and tube plate surfaces of the in-house cooling water cooler 1 turned black and hydrogen sulfide was generated. (See FIGS. 15 and 16). On the other hand, in the experimental area where seawater was not replaced with fresh water (hereinafter referred to as “untreated area”), mussels that had fallen on the manhole cover were observed, and a thick slime, hydroworm, Barnacles were observed (see FIGS. 17 and 18).

(ii) Inspection on May 29 Internal inspection was carried out on May 29, when seawater was passed for about one month from April 18, followed by freshwater treatment for nine days (see FIGS. 19 to 22). In the freshwater treatment section, only a few barnacles were attached to the thin tubes of the in-house cooling water cooler 1, and there were few attached organisms on the surfaces of the thin tubes and the tube sheet (see FIGS. 19 and 20). On the other hand, in the untreated area, a large amount of blue mussels, barnacles, and slime were attached, and the tube was covered with attached organisms (see FIGS. 21 and 22).

(iii) Inspection on June 30 Sea inspection was conducted on June 30 when seawater was passed for 25 days from May 29 and then treated with fresh water for 7 days (see FIGS. 23 to 26). In the freshwater treatment section, the organisms attached to the thin tubes were few and kept clean (see FIGS. 23 and 24). On the other hand, a lot of barnacles and slime adhered to the untreated section, and a portion blocking the narrow tube of the on-site cooling water cooler 1 was observed (see FIGS. 25 and 26).

  From the above observation results, in the freshwater treatment area, the narrow tube of the in-house cooling water cooler 1 is kept clean compared to the untreated area, and the freshwater treatment is the growth of marine organisms in the in-house cooling water cooler 1. The conclusion that it was effective as a preventive measure was obtained.

(2) Measurement results of mussel shell length composition and mortality The mussel was collected from the in-house cooling water cooler 1 on May 29 and June 23, and the shell length composition and mortality were measured. The mortality rate was determined by dividing the number of dead individuals (including shell-only individuals) by the total number of individuals. The measurement results of mussel shell length composition and mortality are shown below.

  First, the mortality rate of mussels collected on May 29 was 100% in the freshwater treatment area and about 50% in the non-treatment area. The mortality rate of mussels collected on June 23 was as high as 94% in the freshwater treatment area (see FIG. 27). Here, data in the untreated section on June 23 is not shown.

  The mussel collected from the cooling water cooler 1 in the power station No. 3 on July 14 was attached in a tuft shape, and a part of the life and death and the shell length were measured (see FIGS. 28 to 30). The mortality rate was 0%.

  The shell length of dead individuals in the freshwater treatment area collected on May 29 was in the range of 5 to 56 mm, and the average shell length was 34 mm (see FIG. 31). On the other hand, the shell length of dead individuals in the untreated section was in the range of 4 to 62 mm, and averaged 36 mm (see FIG. 32). In addition, the number of surviving individuals in the untreated group was in the range of 15 to 63 mm, averaged 41 mm, and many individuals had a slightly larger shell length than the dead individuals in the untreated group (see FIG. 33).

  The shell length of dead individuals in the freshwater treatment area collected on June 23 was in the range of 6 to 56 mm, with an average of 26 mm (see FIG. 34). The dead individuals in the untreated area were in the range of 2 to 53 mm, and the average was 17 mm (see FIG. 35).

  FIG. 36 shows the shell length composition of mussel collected from the Unit 3 in-house cooling water cooler 1 on July 14. The shell length of surviving individuals was in the range of 2 to 20 mm, and there were many individuals whose average shell length was as small as 11 mm (see FIG. 36).

  From these results, the following two points were considered. First, the mussel mortality rate was very high in the freshwater treatment area, which proved effective in suppressing the growth of mussels. In other words, the mortality rate in the untreated section was, for example, about 50% at the time of collection on May 29, which was a big difference from the freshwater treated section. The mortality rate of mussels collected from Unit 3 on July 14 was very low at 0%. From this, the mortality rate of mussels in the in-house cooling water cooler 1 in which seawater is constantly flowing is low at least in July, which is considered to be a major cause of reducing the performance of the in-house cooling water cooler 1. It was.

  Second, looking at the shell length composition of the untreated area, there were relatively many large individuals in the collection on May 29 (see Fig. 33), while juveniles produced this year in the collection on June 23. Accounted for the majority (see FIG. 35). Furthermore, in the mussel community collected on July 14, the larvae of 20 mm or less produced in the current year solidified (see FIG. 28, etc.), causing the deterioration of the performance of the in-house cooling water cooler 1 in the summer. One possible reason was the presence of mussels that adhere in this manner.

  Furthermore, as a result of this example, it is concluded that the fresh water treatment can be kept clean by performing the fresh water treatment once a month in April to June for 1 to 2 weeks. It was.

  In the above-mentioned embodiment, the treatment contents and the results have been described for the hot water treatment as the item 1 and the fresh water treatment as the item 2, respectively. However, the marine organisms can be more effectively controlled by performing the treatment combining them. Needless to say.

It is a graph which shows the change (May, 2003) of the water temperature in an in-house cooling water cooler. It is a graph which shows the change (June, 2003) of the water temperature in an in-house cooling water cooler. It is a graph which shows the change (July, 2003) of the water temperature in an in-house cooling water cooler. It is a figure which shows the schedule of the fresh water treatment and inspection observation implemented in the period of April to June of 2003 (Heisei 15). It is a graph which shows the comparison result of the resistance to mussel in fresh water and the resistance to dryness, and the line and number in the figure represent half-lethal time. It is an image which shows the external appearance (side surface) of an in-house cooling water cooler. It is an image which shows the external appearance (upper part) of an in-house cooling water cooler. It is an image which shows the external appearance (lower part) of an in-house cooling water cooler. It is a figure which shows the outline in the power plant in this embodiment. It is a figure which shows the outline of the structure of the in-house cooling water cooler in this embodiment. It is a figure shown about the in-house cooling water cooler at the time of implementing a warm water process as a prevention | control process. It is a flowchart which shows the procedure of the warm water process in this embodiment. It is a figure shown about the in-house cooling water cooler at the time of implementing fresh water substitution as control treatment. It is a flowchart which shows the process sequence of the fresh water substitution in this embodiment. It is an image which shows the actual adhesion situation (April 18, 2003) of the marine organism in the in-house cooling water cooler in a freshwater treatment area. FIG. 16 is an enlarged view of a part of the image shown in FIG. 15. It is an image which shows the actual adhesion situation (April 18, 2003) of the marine organism in the in-house cooling water cooler in an untreated zone. 18 is an enlarged view of a part of the image shown in FIG. It is an image which shows the actual adhesion state (May 29, 2003) of the marine organism in the in-house cooling water cooler in a freshwater treatment area. FIG. 20 is an enlarged view of a part of the image shown in FIG. 19. It is an image which shows the actual adhesion situation (May 29, 2003) of the marine organism in the in-house cooling water cooler in an untreated area. FIG. 22 is an enlarged view of a part of the image shown in FIG. It is an image which shows the actual adhesion situation (June 30, 2003) of the marine organism in the in-house cooling water cooler in a freshwater treatment area. 24 is an enlarged view of a part of the image shown in FIG. It is an image which shows the actual adhesion situation (June 30, 2003) of the marine organism in the in-house cooling water cooler in an untreated zone. 26 is an enlarged view of a part of the image shown in FIG. It is a graph which shows the mortality rate of mussel. It is an image which shows the mussel collected from the in-house cooling water cooler on July 14, 2003. It is an approach image of the blue mussel shown in FIG. It is a further approach image of the blue mussel shown in FIG. It is a graph which shows the shell length composition of the mussel which was collected in the freshwater treatment area on May 29, 2003. It is a graph which shows the shell length composition of a shell or a dead individual among the mussels collected in the untreated section on May 29, 2003. It is a graph which shows the shell length composition of a living individual among the blue mussels collected in the untreated area on May 29, 2003. It is a graph which shows the shell length composition of a shell and a dead individual among the mussels collected in the freshwater treatment area on June 23, 2003. It is a graph which shows the shell length composition of a shell and a dead individual among the blue mussels collected in the untreated section on June 23, 2003. It is a graph which shows the shell length composition of the living individual of the mussel collected from the in-house cooling water cooler on July 14, 2003.

Explanation of symbols

1 Cooling water cooler

Claims (2)

  The seawater that flows inside the power plant cooling water cooler and cools the cooling water in the plant is temporarily stopped and retained in the cooling water cooler in the plant, while the cooling water in the plant is continuous or intermittent. The heat retained in the in-house cooling water is applied to the water staying in the in-house cooling water cooler, and the temperature of the water is increased to adhere to the inside of the in-house cooling water cooler. A method for controlling attached organisms in a cooling water cooler in a power plant, characterized by degrading marine organisms.   2. The power plant according to claim 1, wherein after the seawater flowing through the in-house cooling water cooler is temporarily stopped, the seawater is replaced with fresh water, and then the temperature is increased by applying heat to the fresh water. A method for controlling attached organisms in a cooling water cooler.