JPH1136088A - Electrolytic corrosion protection method capable of executing sea water electrolytic fouling prevention and iron oxide film formation by generation of iron ion and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic corrosion protection method capable of executing both of sea water electrolytic fouling prevention and iron oxide film formation by generation of iron ions by suppressing the adhesion and propagation of oceanic organisms by the hypochlo rite generated by electrolysis of the sea water for execution of cathodic corrosion protection by an external power source system and forming the iron oxide film on the inside surface of an apparatus consisting of a copper alloy by releasing the iron ions into cooling water and an apparatus therefor. SOLUTION: An insoluble electrode 5 and an iron electrode 6 are mounted at the objected to be corrosion-protected in the state of insulating both electrodes from the objected to be corrosion-protected. The insoluble electrode 5 and the iron electrode 6 are respectively connected to a DC power source device 9 for electrolysis in such a manner that the polarities of the insoluble electrode 5 and the iron electrode 6 are made respectively counter in polarities. The constitution to allow the alternation of the polarities of the insoluble electrode 5 and the iron electrode 6 is adopted. The sea water electrolytic pollution prevention and the iron oxide film formation by the generation of the iron ions are executed by connecting the insoluble electrode 5 to a positive pole at the time of suppressing the adhesion and propagation of the oceanic organisms to the objected to be corrosion protected and connecting the iron electrode 6 to the positive pole at the time of eluting the iron ions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for using seawater as cooling water (for example, a condenser, a heat exchanger, a seawater intake facility, a seawater pipe, etc.) while performing cathodic protection by an external power supply system, The hypochlorite generated by the electrolysis of seawater suppresses the adhesion and propagation of marine organisms, and releases iron ions to cooling water to form an iron oxide film on the inner surface of the copper alloy, thereby forming seawater electrolysis. The present invention relates to an anticorrosion method capable of performing both antifouling and formation of an iron oxide film by generating iron ions, and an apparatus therefor.

[0002]

2. Description of the Related Art As shown in FIG. 5, heat exchangers and condensers using seawater as cooling water are used to protect the steel, stainless steel, copper alloy and the like used in these facilities, as shown in FIG. An iron electrode 55 as an anode, an auxiliary cathode 52 made of mild steel different from a cathode serving as an anticorrosion target, and a reference electrode 7 for detecting the potential of the anticorrosion target are provided. And an external power supply type cathodic protection device comprising a constant current / constant potential power supply device 14 for controlling the potential of the object to be protected and the sum of the protection current and the auxiliary current to be constant. (See Japanese Patent Publication No. 57-15667). In FIG. 5, 1 is a heat exchanger or a condenser, 2 is a cooling pipe, 3
Is a tube sheet, 54 is an insulating plate, and the cooling pipe 3 is generally made of a copper alloy pipe. Corrosion protection by this external power supply type cathodic protection system is achieved by using iron electrode 55 for the anode.
Iron ions generated from the iron electrode 55 form a corrosion-resistant iron oxide film on the inner surface of the copper alloy cooling tube 2, and have no external corrosion protection function by an external power supply method. It exhibits an excellent anticorrosive effect when used in combination.

[0003] On the other hand, equipment that uses seawater as cooling water is often used for cooling marine organisms, such as mussels, barnacles, and algae. In order to prevent damage such as corrosion of the adhered portion of the seawater, an electrolytic cell is installed in the seawater intake pipe line of the equipment that uses seawater on ships, and a DC current that is generated by the insoluble anode is used for electrolytic protection. Produces hypochlorite by electrolyzing seawater,
A technique of using this hypochlorite to prevent marine organisms from attaching to equipment using seawater is also known (Japanese Patent Publication No. Sho-46).
No. 33562), a technique for generating hypochlorite by electrolyzing seawater and using this hypochlorite to prevent marine organisms from attaching to equipment using seawater is generally known. It is called "seawater electrolytic antifouling".

[0004]

An electrolytic cell is provided in the seawater intake pipe line, and seawater is electrolyzed by a direct current from an insoluble anode to produce hypochlorite, and this hypochlorite is used. There is no problem in preventing marine organisms from adhering to equipment using seawater when the seawater intake pipe line is short, such as in ships. If the intake and the heat exchanger or condenser are connected by a seawater intake pipe that extends several hundred meters, an electrolytic cell may be installed in the middle of the seawater intake pipe line to generate sufficient hypochlorite. However, most of them are consumed in the seawater intake pipe line, and the heat exchanger and the condenser have almost no effect on the antifouling of seawater electrolysis.

[0005] Therefore, in order to enhance the seawater electrolysis antifouling effect of the heat exchanger or the condenser, it is conceivable to install an insoluble anode directly in the water chamber of the heat exchanger or the condenser to perform the seawater electrolysis antifouling. However, in order to achieve a sufficient seawater electrolytic antifouling effect, a current of 5 to 10 times the current required to protect the same heat exchanger or condenser is required. Alternatively, the water chamber of the condenser and the cooling pipe become over-corrosive and accumulate electrolysis products, which cause the cooling pipe to close and reduce the heat transmission coefficient, so that it is always kept in the state of seawater electrolytic antifouling. It is not preferable. On the other hand, it is not enough to prevent corrosion of copper alloy cooling pipes simply by applying normal corrosion protection current and conducting electrolytic protection.It is also necessary to perform corrosion protection by generating iron ions and forming an iron oxide film. is there. Therefore, there is a need for a method and an apparatus for preventing corrosion of seawater by electrolysis and generating iron ions.

[0006]

Therefore, the present inventor conducted a study to develop an electrolytic protection method and an apparatus for performing such anti-fouling of seawater and generation of iron ions. As a result, the results are shown in FIG. As described above, the insoluble electrode 5 and the iron electrode 6 are installed close to each other in the water chamber 4 of the heat exchanger or the condenser 1, and the polarity switch 20 and the contacts 21P, 21N, 2
2P, as the insoluble electrode 5 and the iron electrode 6 is a counter electrode through 22N, and connected to the positive terminal P and the negative terminal N ₁ of the electrode for the DC power supply device 9, seawater electrolysis by switching the polarity switching 20 When the antifouling is switched, seawater electrolytic antifouling can be performed strongly. On the other hand, when the polarity switch 20 is switched to the generation of iron ions, iron ions flow into the cooling pipe made of copper alloy and iron oxide is introduced into the cooling pipe. A film is formed, thereby making it possible to strongly prevent corrosion of the copper alloy cooling pipe, and to solve the above-mentioned problem by alternately performing switching between seawater electrolytic antifouling and iron ion generation according to environmental changes. That's the finding.

That is, when seawater electrolysis is carried out by switching the polarity changeover switch 20, the insoluble electrode 5 is connected to the positive electrode.
When the iron electrode 6 is switched to be a negative electrode and the polarity switch 20 is switched to generate iron ions, the insoluble electrode 5 is switched to a negative electrode, and the iron electrode 6 is switched to a positive electrode. Most of the generated current flows into the negative electrode, and the remaining part of the current is passed to the water chamber 4, the tube sheet 3, and the end of the cooling pipe 2 so that they can be controlled to an appropriate anticorrosion potential. It has been found that the above problem can be solved by providing the detection reference electrode 7 and the DC power supply device for cathodic protection 14.

As shown in FIG. 2, an insoluble electrode 5, an iron electrode 6, and a cathode 2 are provided in a water chamber 4 of a heat exchanger or a condenser 1.
4 and the connection switch 25.
Either the insoluble electrode 5 or the iron electrode 6 is connected to the positive terminal P of the DC power supply 9 for electrolysis via the contacts 26P and 27P, and the cathode 24 is connected to the negative electrode of the DC power supply 9 for electrolysis. Connect to N1, connect switch 2
When the seawater electrolysis and antifouling are switched by switching 5, the seawater electrolysis and antifouling can be performed strongly. On the other hand, when the connection changeover switch 25 is switched to iron ion generation,
Iron ions flow in and an iron oxide film is formed inside the copper alloy cooling pipe, which can strongly prevent corrosion of the copper alloy cooling pipe and switch between seawater electrolytic antifouling and iron ion generation in the environment. The inventor has found that the above problem can be solved by taking turns in response to a change. That is,
When the seawater electrolytic antifouling is performed by switching the connection changeover switch 25, the insoluble electrode 5 is switched to be a positive electrode, and when iron ions are generated, the iron electrode 6 is switched to be a positive electrode. Most of the current generated from the positive electrode flows into the cathode 24, and the remaining part of the current is transferred to the water chamber 4,
The above-mentioned problem is solved by providing the reference electrode 7 for potential detection and the DC power supply device 14 for cathodic protection so that the tube sheet 3 and the cooling pipe 2 can be turned around the pipe ends and controlled at an appropriate corrosion protection potential. We learned that we can do it.

The present invention has been made on the basis of such findings. (1) The insoluble electrode 5 and the iron electrode 6 are attached to the anticorrosion target in a state where the anticorrosion target is insulated from the anticorrosion target. And the iron electrode 6 are connected to the DC power supply for electrolysis 9 so as to be opposite electrodes to each other, and the polarity of the insoluble electrode 5 and the iron electrode 6 can be switched. Connected to the negative electrode of the DC power supply for cathodic protection 14, and connected the positive electrode of the DC power supply 14 for cathodic protection to the positive electrode of the DC power supply 9 for electrolysis,
In order to suppress the adhesion and propagation of marine organisms to the anticorrosion target, the insoluble electrode 5 is connected to the positive electrode of a DC power supply 9 for electrolysis, and seawater is electrolyzed by a DC current flowing out of the insoluble electrode 5 to form a sub-electrode. When a part of the direct current reaches the anticorrosion target while chlorate is generated, the anticorrosion is performed, and iron ions are eluted to form an iron oxide film on the anticorrosion target. 6 is connected to the positive electrode of the direct current power supply device 9 for electrolysis to generate iron ions by a direct current flowing out of the iron electrode 6, and to allow a part of the direct current to reach the object to be protected, thereby preventing seawater from being subjected to cathodic protection. An anticorrosion method capable of forming an iron oxide film by electrolytic antifouling and generation of iron ions. (2) An insoluble electrode 5, an iron electrode 6, and a cathode 24 different from the anticorrosion target are used for the anticorrosion target. And the cathode 24 is attached in an insulated state. The insoluble electrode 5 is connected to the negative electrode of the dissolving DC power supply 9 to suppress the adhesion and propagation of marine organisms to the anticorrosion target, and the iron electrode 6 is connected to the electrolytic DC power supply to elute iron ions. A connection switching device 24 is provided between the insoluble electrode 5 and the iron electrode 6 and the DC power supply device 9 for electrolysis so as to be connected to the positive electrode of the power supply device 9. When the positive electrode of the direct current power supply for electrolytic protection 14 is connected to the negative electrode and the positive electrode of the direct current power supply 9 for electrolysis, respectively, to prevent the adhesion and propagation of marine organisms to the anticorrosion target, the positive electrode flows out from the insoluble electrode. When a part of the direct current reaches the object to be anticorrosive while electrolyzing seawater by the direct current to generate hypochlorite, and the electrolytic protection is performed, and when the iron ions are eluted, the direct current flowing from the iron electrode is used. To the current Cathodic protection method capable of performing an iron oxide film formed by seawater electrolysis antifouling iron ion generator for electrical corrosion and while generating a Li Tie ions allowed reaching a portion of the DC current-proof food object,
(3) An insoluble electrode 5, an iron electrode 6, and an electrolysis direct-current power supply device 9 which is connected so that the insoluble electrode 5 and the iron electrode 6 become opposite electrodes and serves as a power source for seawater electrolysis and iron ion elution. And polarity switching device 19 between insoluble electrode 5 and iron electrode 6
And a reference electrode 7 for detecting the potential of the anticorrosion target.
Seawater electrolytic antifouling and iron ion generation, comprising: a potential detection reference electrode 7; an anticorrosion target; and a cathodic anticorrosion DC power supply 14 to which the positive electrode of the electrolysis DC power supply 9 is connected. An electrolytic protection device capable of forming an iron oxide film, wherein the DC power supply device for electrolysis 9 is composed of a constant current rectifier circuit 10 and a constant current control circuit 13, and the DC power supply device for electrolytic protection is 14 An anticorrosion device comprising a potential rectification circuit 15 and a constant potential control circuit 17 capable of forming seawater electrolytic antifouling and forming an iron oxide film by generating iron ions; (4) an insoluble electrode 5 and an iron electrode 6; A cathode 24 separate from the anticorrosion target; an electrolysis DC power supply 9 having the cathode 24 connected to the negative electrode and the insoluble electrode 5 and the iron electrode 6 connected to the positive electrode, respectively, and serving as a power supply for seawater electrolysis and iron ion elution. The said A connection switching device 25 is provided between the neutral electrode 5 and the iron electrode 6 and the positive electrode of the DC power supply device 9 for electrolysis, and further includes a reference electrode 7 for detecting the potential of the anticorrosion target, and the reference electrode 7 for detecting the anticorrosion. DC power supply for cathodic protection 14 connected to the object and the positive electrode of DC power supply 9 for electrolysis
An anticorrosion device capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation comprising:
The electrolysis DC power supply 9 is composed of a constant current rectifier circuit 10 and a constant current control circuit 13, and the cathodic protection DC power supply 14 is composed of a constant potential rectifier circuit 15 and a constant potential control circuit 17. An anticorrosion device capable of forming an iron oxide film by electrolytic antifouling and iron ion generation,
(5) The DC power supply device 9 for electrolysis, the DC power supply device 14 for cathodic protection, and the polarity switching device 19 for the insoluble electrode 5 and the iron electrode 6 are integrally configured as a constant current constant potential power supply device 18. (3) an anticorrosion device capable of forming an iron oxide film by generation of iron ions and seawater electrolysis according to (3), (6) the DC power supply device 9 for electrolysis and the DC power supply device 14 for anticorrosion. The seawater electrolysis according to (4), wherein the connection switching device 28 for switching the connection between the insoluble electrode 5 and the iron electrode 6 and the DC power supply device 9 for electrolysis is integrally configured as a constant current / constant potential power supply device 18. It is characterized by an anticorrosion device capable of forming an iron oxide film by antifouling and generation of iron ions.

In the cathodic protection using an external power supply system according to the present invention, the anti-corrosion device capable of forming seawater electrolytic antifouling and forming an iron oxide film by generating iron ions forms an insoluble electrode 5 comprising Pb-Ag (2% Ag). And the remainder is Pb
Electrodes made of platinum, titanium-plated titanium, niobium or titanium alloy, electrodes coated with a metal oxide on a metal (for example, an electrode in which a platinum group oxide film is formed on the surface of a titanium or titanium alloy substrate) ) Can be used. Further, as the iron electrode 6, a normal mild steel electrode can be used. Further, as the cathode 24, a normal mild steel plate, a rod-shaped body, or the like can be used.

Next, a cathodic protection method using an external power supply system according to the present invention and an anticorrosion method capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation, and particularly a DC power supply device 9 for electrolysis, are provided. The portion of the DC power supply 14 for cathodic protection will be specifically described with reference to the drawings. FIG. 3 is a schematic diagram of an electrolytic protection device capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation of the present invention attached to a condenser. In FIG. 2 is a copper alloy cooling pipe, 3 is a copper alloy tube sheet,
Reference numeral 4 denotes a water chamber, and the water chamber 4 is made of mild steel with an inner surface lining with a rubber lining. An insoluble electrode 5 and the iron electrode 6 are attached to the water chamber 4 at positions adjacent to each other while being electrically insulated from the water chamber 4. Note that the insoluble electrode 5 and the iron electrode 6 may be integrally formed in an electrically insulated state, and may be attached to the wall surface of the water chamber 4 in an electrically insulated state.

Further, a reference electrode 7 is attached to the water chamber 4 near the tube sheet 3 in a state of being electrically insulated from the water chamber 4 for detecting the anticorrosion potential in the condenser 1. The insoluble electrode 5
Contacts 21P polarity switching device 19, to 21N, the iron electrode 6 contacts 22P, respectively connected to 22N, the positive terminal P or connected to the negative terminal N ₁ of the polarity switching 20 electrolytic DC power supply device through 9 Have been. Further, the water chamber 4 is connected to the negative terminal N ₂ and the potential detection positive terminal D of the cathodic protection DC power supply 14, and the reference electrode 7 is connected to the potential detection negative terminal R of the cathodic protection DC power supply 14, respectively. It is connected.

The DC power supply for electrolysis 9 is a constant current rectifier circuit 1.
0 and a constant current control circuit 13, and the DC power supply for cathodic protection 14 has a constant potential rectification circuit 15 and a constant potential control circuit 17. The AC input power supply 8 is connected to a constant current rectifier circuit 10 and a constant potential rectifier circuit 15.

The positive terminal of the constant current rectifier circuit 10 is a current detector 1
To the positive terminal P via the 1 and 12, the negative electrode are respectively connected to the negative terminal N _1, also, the positive electrode of the constant potential rectifier circuit 15, a current detection of the constant current control unit 9 via the current detector 16 is connected between the vessel 11 and the current detector 12, the negative electrode is connected to the negative terminal N ₂

The positive terminal of the constant current control circuit 13 is the current detector 1
Between 1 and 12, the negative electrode is connected between the current detector 12 and the positive terminal P, respectively. Further, a constant potential control circuit 1
7 has a positive electrode connected to the potential detection positive terminal D and a negative electrode connected to the potential detection negative terminal R.

In such a configuration, when performing seawater electrolytic antifouling, the polarity switch 20 is set to the contacts 21P, 21P.
N, the insoluble electrode 5 is connected to the positive terminal P of the DC power supply 9 for electrolysis, and the iron electrode 6 is connected to the negative terminal N ₁ of the DC power supply 9 for electrolysis. The seawater is electrolyzed by I ₀ to generate hypochlorite. When iron ions are generated, the polarity switch 20 is switched to contact the contacts 22P and 22N, the iron electrode 6 is connected to the positive electrode terminal P of the DC power supply 9 for electrolysis, and the insoluble electrode 5 is connected to DC for electrolysis. The iron electrode is connected to the negative electrode terminal N ₁ of the power supply device 9, and the iron electrode is electrolyzed by the electrolytic current I ₀ using the iron electrode 6 as an anode to elute iron ions.

In both the case of performing seawater electrolytic antifouling and the case of generating iron ions, the potential of the pipe end of the cooling pipe 2 of the condenser 1, the pipe sheet 3 and the water chamber 4 is determined by the reference electrode 7 The corrosion prevention current I ₂ is controlled by the constant potential control circuit 17 of the DC power supply for cathodic protection 14 so as to keep the potentials of the pipe end of the cooling pipe 2, the tube plate 3 and the water chamber 4 at predetermined values. ing. Further, the electrolytic current I ₀ detected by the current detector 12 is fed back to the constant current control circuit 13 in both cases of performing seawater electrolytic antifouling and generating iron ions. 13, a signal S ₁ is constantly generated, and the cathode inflow current I output from the constant current rectifier circuit 10 is output.
₁ is controlled, and the sum of the cathode inflow current I ₁ and the anticorrosion current I ₂ , that is, I ₁ + I ₂ = electrolysis current I ₀ is maintained at a predetermined current value.

Thus, the end of the cooling pipe 2 of the condenser 1
By controlling the electrolytic current I ₀ to a predetermined current value while maintaining the tube sheet 3 and the water chamber 4 at an appropriate anticorrosion potential, it is possible to form a seawater electrolytic antifouling action and form an iron oxide film by generating iron ions. Can be performed cathodic protection.

If the DC power supply 9 for electrolysis, the DC power supply 14 for cathodic protection, and the polarity switch 19 having an automatic polarity switching function are integrally configured as a constant current / constant potential power supply 18, the power supply can be provided. As a whole, it is possible to perform a cathodic protection having both a seawater electrolytic antifouling action that is simpler in operation and maintenance and a cathodic protection capable of forming an iron oxide film by generating iron ions.

[0020]

[Action] Normally, marine organisms are attached by the capacity of the condenser.
Required quantity of sodium hypochlorite required to control breeding
Ions required to protect the inside of copper and copper alloy cooling tubes
Since the amount of generation is determined, seawater electrolytic antifouling and iron ion
Electrolytic current I for generation ₀Is constant. But general
It is said that marine organisms attach and reproduce in summer and less in winter
In summer, the polarity switch 20 is set to contact 2
1P, 21N, and contact the insoluble electrode 5 with a direct current
The iron electrode 6 is connected to the positive terminal P of the power source device 9 by a DC power supply for electrolysis.
Negative terminal N of the terminal 9₁To the insoluble electrode 5
Current I generated from₀Electrolyze seawater by
It is necessary to perform the operation for generating the citrate for a long time. this
The operation of switching the polarity changeover switch 20 is a signal
It is convenient to do this.

The reference electrode 7 detects the potential of the copper alloy cooling pipe 2, the copper alloy tube sheet 3 and the water chamber 4 of the condenser,
These are installed as a sensor for cathodic protection, the potential detected by the reference electrode 7 is, so as not to deviate from a predetermined value, the signal S ₂ is emitted at all times from the constant voltage control circuit 17, the constant potential rectifier Corrosion protection current I flowing out of circuit 15
With ₂ are controlled, the cathode inflow current I ₁ and the seawater electrolysis current I ₀ is the constant current control circuit 1 is the sum of the protective current I ₂
3 and is maintained at a predetermined current value.

A residual chlorine meter (not shown) is provided downstream of the seawater.
To achieve a more appropriate seawater electrolytic antifouling by controlling the residual chlorine concentration at a constant level by combining the electrolytic antifouling apparatus capable of performing iron ion generation with the seawater electrolytic antifouling of the present invention. In addition, a polarization resistance measuring device (not shown) for measuring the surface resistance of the iron oxide film formed on the inner surface of the cooling pipe 2 and the seawater electrolytic antifouling and iron ion generation of the present invention can be performed. By combining the anticorrosion devices that can be used, the surface resistance of the iron oxide film can be controlled to be constant, and the corrosion of the inner surface of the cooling pipe 2 can be more appropriately achieved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment FIG. 4 shows an embodiment of an electrolytic protection method and apparatus capable of performing seawater electrolytic antifouling and forming an iron oxide film by generating iron ions while performing cathodic protection using an external power supply system according to the present invention.
This will be described more specifically with reference to FIG. FIG. 4 is a schematic view showing a state in which the electrolytic protection device capable of forming an iron oxide film by the generation of iron ions by seawater electrolytic antifouling of the present invention is applied to a model capacitor. The model condenser uses a water chamber 4 with rubber lining made of mild steel, the tube sheet 3 is made of brass, and the inner diameter between the seawater inlet water chamber and the outlet water chamber is 23 m.
22 cooling pipes 2 made of copper alloy having a length of 1200 mm and a length of 1200 mm were arranged in parallel, and two cooling pipes having almost the same configuration as the actual machine were produced.

A pipe 23 for feeding seawater is attached to the water chamber 4 of each model condenser, and the flow rate of the actual seawater pumped by the submersible pump is set to about 65 m so that the flow velocity in the cooling pipe 2 becomes about 2.0 m / s. ^{At 3} / h, the water was flowed into the seawater inlet water chamber 41 and discharged from the seawater outlet water chamber 42.

One of the model condensers is provided with an anticorrosion device capable of forming an iron oxide film by electrolytically contaminating seawater and generating iron ions according to the present invention, and four insoluble electrodes 5 are provided in a seawater inlet water chamber 42. And two iron electrodes 6, and further, a set of silver chloride reference electrodes 7 ′ is installed at the center of the tube sheet 3, and the tube sheet 3 and the silver chloride reference electrodes 7 ′ are connected to the DC power supply for electrolysis and the electric protection. The edible DC power supply was connected to a constant current constant potential power supply 18 integrally formed, and a polarity switching device 19 was connected between the insoluble electrode 5 and the iron electrode 6 and the constant current constant potential power supply 18.

When the insoluble electrode 5 is used as an anode, a DC current is applied to the model condenser thus installed so that the effective chlorine concentration in seawater is about 0.05 ppm, and the iron electrode 6 is used as an anode. The test was conducted for 6 months while applying a direct current so that the iron ion concentration in the seawater was about 0.04 ppm and maintaining the potential in the water chamber at -600 mV. During the test, the polarities of the insoluble electrode 5 and the iron electrode 6 were switched every two hours. After completion of the test, the state of adhesion of the iron oxide film in the cooling pipe was observed, and a red iron oxide film was formed. Further, the water chamber was opened to observe the state of attachment of the marine organisms, the attached marine organisms were collected, dried, and weighed. The results are shown in Table 1.

Conventional Example On the other hand, a conventional external power supply anti-corrosion device using an iron electrode as the anode shown in FIG. 5 is attached to another one of the model capacitors, a direct current is supplied, and the potential in the water chamber is increased. To -6
After conducting the test for 6 months while maintaining the voltage at 00 mV, the state of adhesion of the iron oxide film in the cooling pipe was observed. As a result, a red iron oxide film was formed. Further, the water chamber was opened to observe the state of marine organisms attached, the attached marine organisms were collected, dried, and weighed. The results are shown in Table 1.

[0028]

[Table 1]

[0029]

From the results shown in the examples, the conventional examples, and Table 1, the iron oxide film is formed on the inner surface of the cooling pipe in both the examples and the conventional examples. By using an anticorrosion device that can form an iron oxide film by generation, the amount of marine organisms attached is reduced to about one-fourth or less of that of conventional marine organisms. The operation efficiency of heat exchangers or condensers can be greatly improved, and the proper corrosion protection potential of the water chamber, tube plate and cooling pipe end can be greatly reduced. While maintaining the same, an excellent effect is achieved such that an iron oxide film is formed on the inner surface of the cooling pipe made of a copper alloy to prevent corrosion of the inner surface of the cooling pipe.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view of an anticorrosion apparatus capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation of the present invention.

FIG. 2 is a schematic cross-sectional explanatory view of another electrolytic protection apparatus capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation of the present invention.

FIG. 3 is a detailed explanatory view particularly showing a constant current / constant potential power supply unit of the cathodic protection apparatus capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation of the present invention.

FIG. 4 is a schematic cross-sectional explanatory view of an anticorrosion device capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation of the present invention.

FIG. 5 is a schematic sectional explanatory view of a conventional external power supply anticorrosion device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Condenser 2 Cooling pipe 3 Tube sheet 4 Water chamber 5 Insoluble electrode 6 Iron electrode 7 Reference electrode 7 'Silver chloride reference electrode 8 AC power supply 9 DC power supply for electrolysis 10 Constant current rectifier circuit 11 Current detector 12 Current detector DESCRIPTION OF SYMBOLS 13 Constant current control circuit 14 DC power supply for cathodic protection 15 Constant potential rectification circuit 16 Current detector 17 Constant potential control circuit 18 Constant current constant potential power supply 19 Polarity switching device 20 Polarity changeover switch 21P contact 21N contact 22P contact 22N contact 23 Seawater water supply pipe 24 Cathode 25 Connection changeover switch 26P contact 27P contact 28 Connection changeover device P Positive terminal N1 Negative terminal N2 Negative terminal D Potential detection positive terminal R Potential detection negative terminal I ₀ Seawater electrolysis current I ₁ Cathode inflow current I ₂ Corrosion protection I ₂ Current 41 Seawater inlet water chamber 42 Seawater outlet water chamber

Claims (6)

[Claims] An insoluble electrode and an iron electrode are attached to an anticorrosion target in an insulated state from the anticorrosion target, and the insoluble electrode and the iron electrode are connected to a direct current power supply for electrolysis such that the insoluble electrode and the iron electrode are opposite electrodes to each other. In addition, the configuration is such that the polarity of the insoluble electrode and the polarity of the iron electrode can be switched, and the anticorrosion target is connected to the negative electrode of the DC power supply for cathodic protection, and the positive electrode of the DC power supply for cathodic protection is When connected to the positive electrode of a direct current power supply for electrolysis, to suppress the adhesion and propagation of marine organisms to the anticorrosion target, the direct current flowing from the insoluble electrode by connecting the insoluble electrode to the positive electrode of the direct current power supply for electrolysis By electrolyzing seawater to generate hypochlorite, a part of the direct current reaches the anticorrosion target to perform electrolytic protection, and elutes iron ions to form an iron oxide film on the anticorrosion target. When forming The electrode is connected to the positive electrode of the direct current power supply for electrolysis, and the iron current is generated by the direct current flowing out of the iron electrode, and a part of the direct current reaches the object to be subjected to the anticorrosion to perform the cathodic protection. An anticorrosion method capable of forming an iron oxide film by electrolytically contaminating seawater and generating iron ions. 2. An insoluble electrode, an iron electrode, and a cathode different from the anticorrosion target are attached to the anticorrosion target in a state insulated from the anticorrosion target, and the cathode is connected to the negative electrode of the DC power supply for electrolysis. When suppressing the adhesion and propagation of marine organisms to the object, the insoluble electrode, when eluting iron ions, the insoluble electrode and the iron electrode so that the iron electrode is connected to the positive electrode of the DC power supply for electrolysis, respectively. A connection switching device is provided between the DC power supply for electrolysis and the anticorrosion target is set to the negative electrode of the DC power supply for cathodic protection, and the positive electrode of the DC power supply for anticorrosion is set to the positive electrode of the DC power supply for electrolysis. When connecting to suppress the adhesion and propagation of marine organisms to the anticorrosion target, a part of the DC current is generated while electrolyzing seawater by DC current flowing from the insoluble electrode to generate hypochlorite. For the anticorrosion target When the corrosion prevention is performed and the iron ions are eluted, it is necessary that a part of the DC current reaches the object to be protected while the iron ions are generated by the DC current flowing out of the iron electrode, thereby performing the electrolytic protection. Characteristic anticorrosion method capable of forming an iron oxide film by the generation of iron ions and seawater electrolytic antifouling. 3. An insoluble electrode, an iron electrode, a direct current power supply for electrolysis serving as a power source for seawater electrolysis and iron ion elution, wherein the insoluble electrode and the iron electrode are connected so as to be counter electrodes to each other, A polarity switching device between an insoluble electrode and an iron electrode, further comprising a reference electrode for detecting the potential of the anticorrosion target, a reference electrode for detecting the potential, the anticorrosion target, and a positive electrode of the DC power supply for electrolysis. An anticorrosion DC power supply, comprising: a seawater electrolytic antifouling and an iron oxide film formation by iron ion generation, comprising: a constant current rectifier circuit; It comprises a constant current control circuit, and the direct current power supply for cathodic protection comprises a constant potential rectification circuit and a constant potential control circuit. thing Cathodic protection device that can. 4. A power supply for seawater electrolysis and iron ion elution wherein an insoluble electrode, an iron electrode, a cathode separate from the anticorrosion target, the cathode connected to the negative electrode, and the insoluble electrode and the iron electrode connected to the positive electrode, respectively. A DC power supply for electrolysis, and a connection switching device between the insoluble electrode and the iron electrode and the positive electrode of the DC power supply for electrolysis, and a reference electrode for detecting the potential of the anticorrosion target, A seawater electrolytic antifouling comprising a reference electrode, an anticorrosion target, and a cathodic anticorrosive DC power supply connected to the positive electrode of the electrolytic DC power supply and capable of forming an iron oxide film by generating iron ions. A DC power supply for electrolysis, comprising: a constant current rectifier circuit and a constant current control circuit; wherein the DC power supply for cathodic protection comprises a constant potential rectifier circuit and a constant potential control circuit. Special Cathodic protection apparatus capable of seawater electrolysis antifouling iron oxide film formed by the iron ion generator to. 5. The DC power supply for electrolysis, the DC power supply for cathodic protection, and the polarity switching device for the insoluble electrode and the iron electrode are integrally formed as a constant current and constant potential power supply. An anticorrosion device capable of forming an iron oxide film by seawater electrolytic antifouling and iron ion generation according to claim 3. 6. A constant-current / constant-potential power supply comprising: a DC power supply for electrolysis, a DC power supply for cathodic protection, a connection switching device for switching connection between the insoluble electrode and iron electrode, and a DC power supply for electrolysis. The cathodic protection device capable of forming an iron oxide film by generation of iron ions according to claim 4, wherein the anticorrosion device is formed integrally with the device.