JPH04278198A - Control method of contamination of copper alloy member - Google Patents

Abstract

PURPOSE:To maintain a facility, such as a condenser or the like, in the optimum operating condition by a method wherein the degree of contamination due to slime and the like formed on the surface of copper-alloy members in said facilities is known at real times with respect to every units of said facilities to control the contamination. CONSTITUTION:An electrode 1 for conducting electricity, a tube plate 2 and a zinc reference electrode 4 for detecting the potential of copper-alloy members 3 are provided in a water chamber 5. A DC power supplying device 6 is provided with a current measuring circuit A and a potential measuring circuit E to regulate a conducted current so as to maintain the optimum potential referred by the reference electrode 4. In order to control the contamination of the copper-alloy members 3, the conduction of electricity is stopped temporarily at first and, thereafter, a natural potential is measured by the potential measuring circuit E. Subsequently, said natural potential is compared with a predetermined reference value by a measuring device 7 and when the natural potential has become more noble than the reference value, a contamination washing means of copper-alloy members is operated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for controlling contamination of copper alloy members, and more specifically, to cooling pipes made of copper alloy in equipment such as condensers and heat exchangers that use seawater as cooling water. The present invention relates to a method for managing dirt by partially and in real time grasping the degree of dirt such as slime formed on the surface of a tube plate or the like (hereinafter referred to as a copper alloy member).

0002

2. Description of the Related Art The inner surfaces of copper alloy members in equipment such as condensers and heat exchangers that use seawater as cooling water are susceptible to corrosion such as inlet attack and deposit attack due to the flow of cooling water. Therefore, as a means of suppressing such corrosion, a combination of cathodic protection methods using external power sources, etc., and a method of supplying iron ions into cooling water to form an iron film on the surface of copper alloy members has been widely implemented in recent years. There is.

However, since such equipment uses seawater as cooling water, microorganisms (usually plankton) in the cooling water and manganese ions floating from the seabed adhere to the inner surface of the copper alloy member ( (generally referred to as slime), problems such as a decrease in the anticorrosion effect of the iron coating and a decrease in the heat transmission efficiency of equipment occur.

[0004] Therefore, it is necessary to appropriately remove such stains on the members due to slime and the like by a cleaning method such as soft ball cleaning, hard ball cleaning, jet cleaning, brush cleaning, or the like. However, in order to perform brush cleaning or jet cleaning, it is necessary to stop the equipment for a long period of time (several days), and although soft ball cleaning and hard ball cleaning can be done during operation, the equipment must be temporarily stopped for cleaning evaluation. There is a need. Furthermore, the occurrence of the above-mentioned stains is easily influenced by various factors such as water temperature and season, and there is no regularity.

[0005] Therefore, in order to minimize the downtime of the equipment required for cleaning and to effectively clean the dirt on the copper alloy parts, it is necessary to understand the state of the dirt properly and without stopping the equipment. be.

However, in order to visually check the state of contamination, the equipment must be shut down, and quantitative judgment cannot be made. In addition, it takes a considerable amount of time and effort to collect and analyze such deposits and obtain the results, and the equipment must be stopped during collection, so it is difficult to directly determine the state of dirt from the amount of deposits. It is also difficult.

[0007] Conventionally, a method using a vacuum degree deviation value has been generally used as a method for determining such contamination. This method utilizes the fact that when dirt adheres to copper alloy members, it causes a decrease in heat transfer efficiency, which affects the degree of vacuum on the steam side of equipment such as power plants, and determines the state of dirt from the degree of vacuum deviation value. It has been empirically found that the degree of vacuum deviation value is closely related to the degree of contamination. The degree of vacuum deviation value is the value of (actual degree of vacuum) - (estimated degree of vacuum), and the expected degree of vacuum is a value calculated for each facility based on the capacity of the facility, the number of pumps, the cooling water temperature, etc.

By the way, equipment such as condensers and heat exchangers usually includes a plurality of heat exchange units (condensers; each unit generally includes a plurality of cooling pipes and two water chambers), and the unit It is known that the state of dirt differs depending on the situation. However, in the case of the method using the vacuum degree deviation value, since the steam side of the equipment is usually one in the entire equipment, it is possible to grasp the state of contamination only on average for the entire equipment. Therefore, in the past, it was difficult to detect when dirt was concentrated in one unit of the equipment, and even if it would have been sufficient to clean only one unit with a soft ball at an early stage, all units ended up being cleaned with a brush. There were times when I had no choice but to do it.

[0009]

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is directed to the use of copper alloy members in equipment such as condensers and heat exchangers that use seawater as cooling water. To provide a method capable of efficiently maintaining equipment in a proper operating condition by grasping the degree of dirt such as slime formed on the surface in real time for each unit of the equipment and managing the dirt. The purpose is to

0010

[Means and effects for solving the problem] As a result of intensive research to solve the above problems, the present inventors found that the natural potential of a copper alloy member has a very close relationship with the degree of contamination of the copper alloy member. They discovered this and arrived at the present invention.

That is, the method of controlling stains on copper alloy members of the present invention is to prevent corrosion of copper alloy members used in equipment that requires cooling water by applying the cathodic protection method and forming an iron coating on the surface of the member. In controlling the contamination of the copper alloy member when corrosion prevention is performed in combination with the method, a current circuit that conducts electricity from an electrode provided in the cooling water to the copper alloy member through the cooling water, and a potential of the copper alloy member are controlled. A step of determining the natural potential at which the potential of the cathode (copper alloy member) attenuates and becomes stable after temporarily interrupting the current supply using an energizing device having a potential measuring circuit to be measured; This method is characterized by comprising a step of comparing it with a predetermined reference value, and a step of cleaning the copper alloy member to remove dirt when the natural potential becomes nobler than the reference value.

The surface of the copper alloy member to which the present invention is directed is in contact with cooling water such as seawater or fresh water, and is protected against corrosion by a combination of cathodic protection and corrosion protection using an iron coating. Neither the above-mentioned cathodic protection method nor the corrosion protection method using an iron coating is particularly limited. For example, as a corrosion prevention method using an iron coating, there is a method of supplying iron ions for forming an iron coating by introducing a ferrous sulfate solution or by iron electrolysis using an iron electrode.

In the present invention, the natural potential determined as an index of the degree of contamination is the potential of the copper alloy member (cathode) when no current is applied (depolarized stable potential), that is, the potential attenuates and becomes stable after the current is cut off. This is the cathode potential. Usually, it takes about 5 minutes after the current supply is cut off for the cathode potential to reach the true natural potential.

In the present invention, the above-mentioned natural potential may be actually measured, but from the viewpoint of the effectiveness of cathodic protection and the measurement work, it is preferable to obtain the natural potential by shortening the current cut-off time as much as possible. The following formula (1) En=E60+(E60-E
50) (1
) [In formula (1), En is the natural potential, E50 is the cathode potential 50 seconds after the energization is cut off, and E60 is the cathode potential 60 seconds after the energization is cut off]. is most preferable. Since the natural potential determined based on the following formula (1) substantially matches the actually measured value, it is possible to determine the natural potential in about 1 minute by this method.

[0015] Furthermore, the energizing device used in the present invention is
It is sufficient that it has a current circuit that passes current through the cooling water to the copper alloy member from an electrode provided in the cooling water, and a potential measurement circuit that measures the potential of the copper alloy member, and it also serves as a cathodic protection device using an external power source. This is preferable because the device does not become complicated. Further, such an energizing device may be provided separately from the cathodic protection device. In addition, when the target equipment consists of a plurality of units, it is preferable to provide the above-mentioned energizing device for each unit and obtain the natural potential in each unit.

In the present invention, the natural potential is compared with a predetermined reference value, and if the natural potential is nobler than the reference value, the copper alloy member is cleaned of dirt. The above standard values vary depending on operating conditions, environmental conditions, etc., so it is difficult to set them uniformly, and it is necessary to set them for each piece of equipment or each unit. In setting the above reference value, it is preferable to determine it empirically so that the decrease in the anticorrosion effect of the iron coating and/or the decrease in the heat transfer efficiency of the equipment does not exceed an allowable range. Specifically, for example, the amount of deposits on the copper alloy member may be measured for a certain period of time and the value may be set based on the data, or the value may be set with reference to the conventional degree of vacuum deviation value. If the equipment is to be managed more strictly, the standard value may be set to a lower value. Alternatively, the reference value may be set within a certain range in anticipation of variations in the natural potential, and when the range falls within that range, preparations for cleaning may be made, and when it becomes higher than that range, the cleaning may be performed immediately.

[0017] The method for cleaning the dirt is not particularly limited and is selected depending on the degree of dirt, etc., but soft ball cleaning or hard ball cleaning is preferred since the downtime of the equipment is short (several hours). Cleaning is preferred, with soft ball cleaning being most preferred as there is less risk of removing a good iron coating.

The above-described method of controlling stains on copper alloy members of the present invention can sufficiently control stains by itself, but of course, in order to be more careful, conventional methods such as using the deviation value of the degree of vacuum may be used. It may be done in conjunction with.

Furthermore, it is even more preferable to use the method for controlling contamination of copper alloy members of the present invention in conjunction with the method for measuring iron film resistance (Japanese Patent Application Laid-open No. 147247/1983) proposed by the present applicant. This iron film resistance measurement method involves measuring the iron film resistance (Rf), polarization resistance (Rd), and measured IR Third component resistance value (Rx) including drop
This method makes it possible to separate and measure only the iron film resistance value (Rf) from the iron film resistance value (Rf), and to grasp the state of the iron film based on the iron film resistance value (Rf).

That is, the method for measuring the iron film resistance is as follows:
In the management of anti-corrosion iron coatings when copper alloy members used in equipment requiring cooling water are protected from corrosion using a combination of cathodic protection method and anti-corrosion method by forming an iron coating on the surface of the member. , using a current-carrying device having a current measurement circuit and a potential measurement circuit, the cathode potential and the current value I during energization are determined.
and a step of temporarily interrupting the current flow and measuring the decaying cathode potential until the cathode potential reaches a stable natural potential or until the natural potential can be predicted. , a step of obtaining a potential change value V, which is the difference between the cathode potential after the energization is cut off and the natural potential, for each time after the energization is cut off, and a decay curve of the logarithm logV of the potential change value with respect to time ( (b) obtaining the regression line (b) of the logarithm logV over time after the attenuation curve (a) shifts from an exponential decreasing trend to a linear decreasing trend, and the attenuation curve The process of determining the iron film resistance component potential Vf, which is the difference between (a) and the regression line (b), for each time after the current supply is cut off, and the regression of the logarithm logVf of the iron film resistance component potential Vf with respect to time. Straight line (
(c), and the step of determining the iron film resistance component potential Vf (t=0) at the moment when the current is cut off from the regression line (c), and the obtained iron film resistance component potential Vf (t=0).
The following formula Rf = {Vf (t=0)/I} x {S/K} [in the formula,
This method is characterized by the step of determining the iron film resistance value Rf from the iron film resistance value, S the area to be energized, and K the energization current distribution ratio. Then, using the fact that the iron film resistance value Rf is closely related to the state of the iron film, the state of the iron film can be grasped from the iron film resistance value Rf, and the iron film can be managed by adjusting the amount of current flowing. This is a method that makes it possible.

[0021] In the above method for measuring iron film resistance, the natural potential is determined in the process, but it has not been found that the natural potential has any close relationship with the degree of contamination. It was simply a value necessary to determine the iron film resistance value Rf.

By combining such a method for measuring iron film resistance with the method for controlling contamination of copper alloy members of the present invention, contamination can be managed from the natural potential and furthermore, the iron film resistance can be determined from the iron film resistance value Rf. It becomes possible to grasp the status using the same device at the same time, and it becomes possible to maintain the equipment in a proper operating state more efficiently.

[0023] Hereinafter, an example in which the method for controlling contamination of a copper alloy member of the present invention and the method for measuring iron film resistance described above are carried out together will be described in more detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of an energizing device for implementing the management method of the present invention in a condenser that implements a corrosion protection method using an external power source as a cathodic protection method.

In FIG. 1, a water chamber 5 is provided with an electrode 1 for conducting current, and a zinc reference electrode 4 for detecting the potential of the tube plate surface 2 and the cooling tube 3 (copper alloy member). The DC power supply device 6 is a current measuring circuit (A in the figure).
and a potential measuring circuit (E in the figure), which adjusts the applied current so as to maintain the appropriate potential compared with the reference electrode 4. Also,
7 in FIG. 1 is a measuring device to be described later. Further, although not shown, the condenser is equipped with an iron electrolysis device, a device for introducing ferrous sulfate, or an iron electrode to supply iron ions into the cooling water.

[0026] In carrying out the method for controlling contamination of a copper alloy member of the present invention, the natural potential is measured by the potential measuring circuit after the current supply is temporarily cut off. In addition, when determining the natural potential based on the above formula (1), the cathode potential 50 seconds and 60 seconds after the current supply is cut off is measured by the above potential measuring circuit, and from these data, the measuring device 7 The natural potential is required. Then, the measuring device 7 compares the natural potential with a predetermined reference value, and when the natural potential becomes nobler than the reference value, means (not shown) for cleaning the copper alloy member from dirt is activated. The means for activating the cleaning means is not particularly limited, and a signal may be emitted in such a case, and the cleaning means may be activated manually or automatically.

[0027] When the above-mentioned method for measuring iron film resistance is also carried out, the cathode potential during energization, the energization current value I, and the cathode potential after energization is interrupted are measured by the above-mentioned current measuring circuit and potential measuring circuit, and these are measured. Measuring device 7 from the data of
The iron film resistance value Rf is determined by:

FIG. 2 is a block diagram of an example of the measuring device 7. As shown in FIG.

In FIG. 2, 8 is a central processing unit (CPU) that performs calculations and controls the entire measuring device, and 9 is a central processing unit (CPU) that performs calculations and controls the entire measuring device. 10 is a switch for potential and current analog signals input at multiple points; 11 is an analog-to-digital signal converter that converts potential and current analog signals into digital signals; 12 is measurement results and operation commands; 13 is a keyboard section for inputting various parameters etc. to the measuring device; 14 is a keyboard section for inputting various parameters etc. to the measuring device;
Reference numeral 15 indicates a channel select switch unit used when performing measurements, 15 a printer unit capable of printing measurement results or setting parameter contents, etc. on paper, and 16 a power supply unit that supplies power to the measuring device.

FIG. 3 shows the natural potential En and the iron film resistance value R.
It is a conceptual diagram for simultaneously grasping the state of dirt and iron coating from f.

There is a close relationship in that the natural potential En becomes nobler as the dirt due to slime etc. increases. Furthermore, there is a close relationship in that the thicker the iron coating and the higher the corrosion resistance, the greater the iron coating resistance value Rf. Therefore, by predetermining certain reference values for the natural potential and the iron film resistance value, based on these values, the condition of the iron film and dirt can be determined as shown in Figure 3 in four areas (divided by broken lines). ).

Therefore, if a relationship diagram between the natural potential and the iron film resistance value as shown in FIG. By plotting the values in the same figure, it is possible to simultaneously and easily grasp the contamination of the copper alloy members of the target equipment and the condition of the iron coating.

[0033] If the iron film resistance value is below the standard value, the iron film is strengthened by supplying iron ions, etc., and if the natural potential is nobler than the standard value, dirt is removed by ball cleaning etc. It is possible to give instructions.

FIG. 4 shows an example of a flow when the method for controlling contamination of a copper alloy member according to the present invention is carried out together with the method for measuring iron film resistance and the method using the vacuum degree deviation value.

In FIG. 4, En is the natural potential (mV)
, Rf is iron film resistance (Ω・m2), Rd is polarization resistance (Ω・m2), ΔH is vacuum degree deviation value, t is inlet water chamber temperature (℃), Grade A cleaning is brush cleaning, Grade B cleaning indicates hard ball cleaning, and normal cleaning indicates soft ball cleaning.

As shown in the flowchart of FIG. 4, the natural potential En
, measurement of iron film resistance value Rf, vacuum degree deviation value ΔH, etc.
Memory, calculations, commands, etc. are performed automatically. natural potential E
n and the iron film resistance value Rf are measured for each unit of the target equipment, and their values are shown in Figure 3 based on each standard value.
By plotting on a conceptual diagram like this and observing the time course of the plot, the degree of contamination and the condition of the iron coating can be grasped. Then, depending on the position of the plot in the above conceptual diagram, that is, the degree of contamination and the condition of the iron coating, it is determined for each unit whether cleaning the inside of the pipe is necessary or unnecessary, and whether the iron ion supply device should be operated or stopped based on the degree of contamination such as slime. , it is possible to give appropriate instructions in real time without stopping equipment operation. In addition, the degree of contamination of the entire equipment is also managed by the vacuum degree deviation value ΔH, and if the vacuum degree deviation value ΔH exceeds the standard value, the entire equipment is completely shut down and brush cleaning is performed. be. In addition,
Each reference value shown in FIG. 4 shows an example in actual equipment, and is determined empirically for each equipment or each unit.

[0037]

EXAMPLES The present invention will be explained in more detail below based on Examples, but the management method of the present invention is not limited thereby.

EXAMPLE The management method of the present invention was applied to one unit of a condenser in a thermal power plant equipped with a cathodic protection device using an external power source and an iron ion supply device using iron electrolysis. In this example, since the vacuum degree deviation value ΔH of only that unit was measured, the other units were closed. The target condenser uses seawater as cooling water and is equipped with aluminum brass cooling pipes and naval brass tube plates.

(Setting of reference values) First, a preliminary investigation was conducted to determine reference values for each of the natural potential En and the iron film resistance value Rf in the target condenser.

The inside of the condenser pipe, in which slime deposits such as living organisms and manganese scale had accumulated after 6 months of electrolytic protection and iron ion supply, was jet-cleaned. Thereafter, electrolytic protection and iron ion supply were restarted, and deposits inside the pipe were periodically collected over a period of approximately 3 months to measure the amount of deposits. In addition, at the same time as the collection, the natural potential En,
The iron film resistance value Rf and the degree of vacuum deviation value ΔH were measured.

[0041] Note that the natural potential En is saturated at the saturated electrode (S
CE) standard based on the above formula (1), and as is clear from Table 1, the value is in good agreement with the actually measured natural potential (cathode potential 5 minutes after energization is interrupted). Ta.

[0042]

[Table 1] .

FIG. 5 is a graph showing the relationship between the amount of deposits and the natural potential En and the iron film resistance value Rf, FIG. 6 is a graph showing the relationship between the amount of deposits and the degree of vacuum deviation value ΔH, and FIG.
Graphs showing the relationship between the degree of vacuum deviation value ΔH, the natural potential En, and the iron film resistance value Rf are shown in FIG.

As is clear from FIG. 5, the natural potential En
is closely related to the amount of deposits, and as the amount of deposits inside the pipe (the amount of slime such as living things and manganese scale) increases, the natural potential En becomes nobler, while the iron film resistance value Rf decreases.

In addition, the degree of vacuum deviation value ΔH has been widely used as an index to grasp the degree of contamination of the entire equipment in actual operation, and as shown in FIG. 6, it has a close relationship with the amount of deposits. (However, in normal equipment equipped with multiple units, the amount of deposits is not uniform across all units, so it is not possible to determine the level of contamination for each unit.)

Therefore, in this embodiment, the natural potential En and the iron film resistance value R are determined with reference to the degree of vacuum deviation value ΔH.
Define the standard value of f. That is, in the case where conventionally it was preferable to perform ball cleaning when the vacuum degree deviation value ΔH was 2 to 3 mmHg, for example, if the vacuum degree deviation value ΔH = 3 mmHg,
Based on Hg. The amount of deposits corresponding to this value is 4.5 mg/cm 2 from FIG. 6 . Therefore, in order to control the amount of deposits to 4.5 mg/cm2 or less, it can be seen from FIG. 5 that the reference value of the natural potential En should be set to -150 mV (SCE). In addition, the iron film resistance value Rf
may be set to 0.65Ω·m2 corresponding to that value.

Further, each reference value may be determined directly from the vacuum degree deviation value ΔH based on the relationship between the vacuum degree deviation value ΔH, the natural potential En, and the iron film resistance value Rf shown in FIG.

When each reference value is set in this manner, as is clear from FIG.
super), leading to a decrease in heat transfer efficiency, and the iron film resistance value Rf
If it becomes 0.65Ω・m2 or less, it can be seen that the anticorrosion effect of the iron coating is reduced due to the accumulation of dirt due to slime adhesion, and this becomes the standard for issuing an alarm to clean the inside of the pipe by cleaning the ball or the like.

Therefore, based on each of the above reference values, a conceptual diagram is obtained in which the state of the dirt and the iron coating can be determined simultaneously from the natural potential En and the iron coating resistance value Rf (FIG. 8). By plotting the actual measured values of natural potential and iron film resistance in the same figure, it is possible to simultaneously and easily grasp the contamination of the target member and the condition of the iron film, and take appropriate measures in real time. be able to.

[0050] If the control is to be more strict, for example, the vacuum degree deviation value ΔH = 2 mmHg is used as the reference value, and the corresponding natural potential En = -200 mV and iron film resistance value Rf = 0.7 Ω·m2 are set as the reference values. And it is sufficient.

(Condenser Operation Management) Next, the condenser operation management was actually performed using the above reference values.

After jet cleaning the inside of the condenser pipe to clean the inner surface, electrolytic protection and iron ion supply are started, and the natural potential En, iron film resistance value Rf, and vacuum degree deviation are measured using the above-mentioned measuring device. The value ΔH was measured for about 4 months.

Natural potential En and iron film resistance value Rf
A graph obtained by plotting the actual measured values in FIG. 8 is shown in FIG. In FIG. 9, the black circles (·) indicate actual measured values, and the arrows (→) indicate the passage of time after measurement and the start of condenser operation. In addition,
Measurements began in late spring and were recorded from summer, when slime tends to form, to early fall.

Looking at the measured values in FIG. 9 over time, the measured values shift in a band-like manner and can be roughly divided into four blocks. In other words, immediately after the measurement started (late spring), the inner surface of the tube was clean, the natural potential En was approximately -400 mV, and the iron film resistance value Rf was 0.65 Ω・m2 or less, so the corrosion protection effect of cathodic protection was effective. It is possible to understand that During this time, since iron ions are being supplied at the same time, the iron film resistance value Rf increases with the passage of time. Furthermore, as the iron coating is formed, the natural potential En gradually becomes nobler, but at this stage, the corrosion protection effect due to electrolytic protection is dominant.

In early summer, the iron film resistance value Rf increases rapidly, and the natural potential En also becomes more noble.
It can be seen that the formed iron film has hardened and that slime has started to adhere. It can be seen that during this period there was a gradual transition from corrosion protection by cathodic protection to corrosion protection by iron coating.

In the summer, the natural potential En becomes more noble, and the iron film resistance value Rf rapidly decreases from its peak value, which indicates that slime production is active and dirt becomes noticeable. can. At the end of this period, the iron film resistance value Rf became 0.65 Ω·m2 or less, and the natural potential En also became nobler than -150 mV, so ball cleaning (soft) was carried out according to the flow shown in FIG. In addition,
At the end of the above period, the vacuum degree deviation value ΔH also exceeded 3 mmHg.

As a result of ball cleaning, in late summer the natural potential En and the iron film resistance value Rf recovered to almost the same levels as in early summer (shaded area in the figure), and the dirt and iron film were restored to good condition. I can understand that.

Table 2 below shows the degree of vacuum deviation value ΔH and the degree of iron coating and dirt inside the cooling pipe during the above measurement period.

[0059]

[Table 2] .

As is clear from Table 2, by combining the stain management method of the present invention and the iron coating resistance measurement method described above, it is possible to grasp the condition of the stain and iron coating from the natural potential En and the iron coating resistance value Rf. The results correspond well to the conventional vacuum degree deviation value ΔH and the iron coating and contamination within the cooling pipe, and it can be seen that the degree of contamination is particularly well understood.

Furthermore, when cleaning was carried out in accordance with the stain management method of the present invention, the stain and iron coating were restored to a good condition, which shows that the method of the present invention is effective.

[0062]

[Effects of the Invention] As explained above, the management method of the present invention prevents formation of formation on the surface of copper alloy members such as cooling pipes and tube sheets in equipment such as condensers and heat exchangers that use seawater as cooling water. It becomes possible to grasp the degree of dirt on slime, etc., in real time. By managing the dirt, it is possible to prevent a decrease in the anticorrosion effect of the iron coating and a decrease in the heat transfer efficiency of the equipment for each unit, and it is possible to efficiently maintain the equipment in a proper operating state.

Furthermore, since the self-potential according to the present invention can be measured for each unit in equipment such as a condenser or heat exchanger that consists of a plurality of units, according to the present invention, the state of contamination can be ascertained for each unit. This makes it possible to manage equipment on a unit-by-unit basis very efficiently.

Furthermore, the dirt management method of the present invention can be carried out in conjunction with the method for measuring iron film resistance, thereby making it possible to simultaneously monitor dirt management and the state of the iron film using the same device. This makes it possible to maintain equipment in proper operating conditions more efficiently.

Therefore, according to the present invention, troubles in the equipment can be prevented, and even if an abnormality occurs, it can be immediately dealt with, so that the equipment can be operated safely and efficiently at all times.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an example of an energizing device for implementing the management method of the present invention.

FIG. 2 is a block diagram of an example of a measuring device 7. FIG.

FIG. 3 is a conceptual diagram for simultaneously understanding the state of dirt and iron coating from the natural potential and iron coating resistance value.

FIG. 4 is an example of a flow when the method of controlling dirt on a copper alloy member of the present invention is carried out together with the method of measuring iron film resistance and the method of using a vacuum degree deviation value.

FIG. 5 is a graph showing the relationship between the amount of deposits, the natural potential En, and the iron film resistance value Rf.

FIG. 6 is a graph showing the relationship between the amount of deposits and the degree of vacuum deviation value ΔH.

FIG. 7 is a graph showing the relationship between the degree of vacuum deviation value ΔH, the natural potential En, and the iron film resistance value Rf.

FIG. 8 is a conceptual diagram for simultaneously understanding the state of dirt and iron coating from the natural potential and iron coating resistance value.

FIG. 9 is a graph in which actual measured values of natural potential and iron film resistance are plotted in FIG.

[Explanation of symbols]

1　Electrifying electrode 2　Tube plate surface 3 Cooling pipe 4 Reference electrode 5 Water room 6 DC power supply device 7 Measuring device A Current measurement circuit E　Potential measurement circuit

Claims (5)

[Claims] [Claim 1] A method for preventing corrosion of copper alloy members used in equipment requiring cooling water by using a combination of cathodic protection method and corrosion prevention method by forming an iron coating on the surface of the member. In managing contamination of the member, an energizing device is used that has a current circuit that supplies current to the copper alloy member from an electrode provided in the cooling water through the cooling water, and a potential measurement circuit that measures the potential of the copper alloy member. , a step of determining the natural potential at which the cathode (copper alloy member) potential attenuates and stabilizes after the current supply is temporarily cut off; a step of comparing the natural potential with a predetermined reference value; A method for managing dirt on a copper alloy member, comprising the step of cleaning dirt on the copper alloy member when the potential becomes nobler than the reference value. [Claim 2] The natural potential is expressed by the following formula (1):
En=E60+(E60-E50)
(1) [In formula (1), En is the natural potential (mV), E50 is the cathode potential (mV) 50 seconds after the current is cut off, and E60 is the cathode potential 60 seconds after the current is cut off. The method for controlling stains on a copper alloy member according to claim 1, characterized in that the method is determined based on the following: (mV) respectively. 3. The step of cleaning the dirt is performed by at least one cleaning method selected from the group consisting of soft ball cleaning, hard ball cleaning, and jet cleaning. How to control dirt on copper alloy parts. 4. The reference value is determined empirically so that a decrease in the anticorrosion effect of the iron coating and/or a decrease in heat transmission efficiency of the equipment does not exceed a permissible range. 3. The method for controlling stains on a copper alloy member according to any one of 3 to 3. 5. The method for managing stains on a copper alloy member according to claim 1, wherein the energizing device is a cathodic protection device using an external power source.