KR920004508B1 - Apparatus and method for electrical anti-corrosion of total titanium heat exchanger - Google Patents

Abstract

No content.

Description

Electric method of all titanium heat exchanger and electric method

1 is a system configuration diagram showing a condenser and a piping system connected thereto.

2 is a characteristic diagram showing natural potentials of various metals in seawater.

3 to 5 are schematic diagrams for explaining the propagation phenomenon in the condenser respectively.

6 to 11 are each a schematic diagram showing a conventional electric anticorrosion apparatus.

12 is a potential distribution diagram for explaining the operation of the present invention.

13 is an equipotential distribution diagram for explaining the operation of the present invention.

14 is a schematic diagram showing an embodiment of the present invention.

15 to 17 are diagrams for explaining the operation of FIG.

18 is a schematic diagram showing a second embodiment of the present invention.

19 and 21 are diagrams for explaining the operation of FIG. 18, respectively.

22 is a schematic diagram showing a third embodiment of the present invention.

23 is a schematic diagram showing a fourth embodiment of the present invention.

24 and 26 are diagrams for explaining the operation of FIG. 23, respectively.

27 is a schematic diagram showing another embodiment of the present invention.

28 is a schematic diagram showing another embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical system and an electrical method of an all-titanium heat exchanger used to prevent galvanic corrosion of a piping device connected thereto in an all-titanium heat exchanger using seawater as a refrigerant.

In general, shell and tube types of heat exchangers in which seawater is used as cooling water, for example, as a condenser in a power plant, are widely adopted. Since the condenser's cooling tube is in direct contact with the sea water, the copper tube is made of hard-to-corrosive noble metal, such as copper alloy mainly for aluminum brass, and naval brass plate for plural throttle plates. It is used. On the other hand, steel is used for the condenser chamber and the equipment and piping connected to the condenser. In addition, Monel and stainless steel are used as the thermometer wells of instrumentation products. The following description will be made with reference to FIG. 1 as an example of a condenser for returning steam from a power plant to water and an apparatus, piping, and instrumentation in close proximity to the condenser.

The steam 1 discharged from the steam turbine is introduced into the condenser 2, and comes into contact with the surface of the condensation condenser 2 through which the cooling sea water is distributed, thereby cooling and condensing the condensate 5 into the condenser 5. . This plurality is recovered by the plurality of pumps 4 for reuse in the power plant in the plurality of pumps 2, and the water not shown is sent to the hot air. In general, an aluminum brass tube is used for the cooling tube 3 of the condenser 2. On the other hand, the cooling sea water 6 is generally supplied through an inlet circulating water pipe 7 made of carbon steel coated with an anticorrosive coating or coating material such as tar epoxy resin, and the like through the inlet water chamber 8 described above. While absorbing the heat of the steam (1) through the cooling tube (3) while passing through the inside of the cooling tube (3) made of aluminum brass-related, the temperature rises through the outlet water chamber (9) and the outlet circulating water pipe (10). It is discharged to the outlet (sea). In addition, the inlet circulating water pipe 7 and the outlet circulating water pipe 10 generally have a butterfly valve 11 for stopping and switching the cooling sea water 6 or a thermometer 12 for detecting and monitoring temperature and pressure. (Temperature detection left) and pressure gauge 13 (extrusion detection left) are attached. In addition, a ball cleaning device for maintaining the cleanliness of the inner surface of the cooling tube (3) is provided. That is, the washing ball recovered by the ball collector 14 in the cooling sea water is introduced into the ball recirculation pipe 15 and transported to the ball recovery device 17 through the ball circulation pump 16 and from there the ball injection pipe 18 again. ) Is injected into the cooling seawater flowing in the inlet circulating water pipe (7), and by repeating this, foreign matters attached to the inner surface of the cooling pipe (3) are removed.

In addition, rubber joints 19 are attached to the inlet circulating water pipe 7, the inlet water chamber 8, the outlet water chamber 9, and the outlet circulating water pipe 10 to absorb installation errors and micro displacements during operation. I can do it.

In addition, the air inlet chamber 8 and the air outlet valve 21 are attached to the inlet chamber 8 and the outlet chamber 9 to draw air. In addition, the code | symbol 22 has shown each plate in the figure.

However, the parts which are in contact with the seawater of the condenser or the circulating water pipe are paying close attention to the design such as the selection of materials, the painting of metal surfaces, or the protection of anticorrosive coating materials to prevent corrosion by seawater. That is, corrosion generally includes natural corrosion in which metal units in an acidic environment are corroded, and galvanic corrosion occurs when dissimilar metals are in contact (hereinafter, abbreviated as electrostatic). This type of corrosion is very fast, so special care must be taken. In general, when a heterogeneous metal that is electrically connected is raised in an electrolyte solution, a noble metal becomes a cathode, a nonmetal becomes an anode, and a natural potential difference is formed, and the anode metal becomes a metal ion. It is the phenomenon of dissolution of base metal by dissolution. Figure 2 shows the natural potential of metals in seawater. The beggar showed seven kinds of natural potentials, but titanium is the precious metal and zinc is the least metal. For example, in the seawater, if the precious brass and the nonferrous iron come into contact with water and the brass and the iron are electrically connected, the iron on the side compared with the potential difference (V) between the two metals is transferred by this potential difference. do. In addition, when the precious stainless steel (floating state) and the non-ferrous iron are in contact with each other in seawater, and the stainless steel (floating state) and iron are electrically connected, the iron on the non-ferrous side is transformed by the natural potential difference (V) between the two metals. Suffer The same can be said for other metal combinations, whereby the greater the natural potential difference between the two metals, the more prominent the phenomena are. In addition, the non-side VSCE of the potential of the horizontal axis represents a saturation potential.

These phenomena can also occur in the seawater system of power plants. For example, there is a possibility that electroforming occurs between exposed metals of instrumentation such as cooling tubes, strainers, valves and thermometer wells used in heat exchangers. In addition, the following materials and the following can be considered. That is, the inner surface of the piping equipment is coated with anticorrosive coating or coating so that the steel surface does not come into direct contact with seawater in order to prevent corrosion of the steel surface.

However, if the coating or coating surface is damaged for some reason, the steel surface is exposed to seawater. If the steel surface of the noble metal material and the nonmetal is electrically connected, the steel surface on the opposite side is transferred due to the natural potential difference between the two metals. You will eat. That is, for example, when the aluminum brass tube is used for the cooling tube 3 of the condenser 2 described above, and the naval brass plate is used for the plurality of engine plates 22, the inlet and outlet equations (8, 9) and the inlet, respectively. And the outlet circulation water pipes 7 and 10 are usually made of steel sheet, so that the steel sheet becomes the metal on the non-side.

The inlet and outlet water chambers 8 and 9 and the inlet and outlet circulation water pipes 7 and 10 are coated with an anticorrosive coating or coating material as described above, but their coatings or coatings are poor in construction and seawater. When the steel surface is damaged by the flow and exposed, the steel surface, which is a metal compared to the metal due to the natural potential difference between brass and iron, is exposed as described above.

Hereinafter, this phenomenon will be described in detail.

In FIG. 3, it is assumed that the coating damaged portion 23a is present in the outlet water chamber 9 of the condenser 2 and that the coating damaged portion 23b is also present in the outlet circulation pipe 10. Therefore, the steel surface is exposed to the coating damage parts 23a and 23b. It is assumed that the condenser 2 is grounded by a foundation or the like, and the outlet circulation pipe 10 is also grounded by a support of a piping device or an underground pipe. In view of the foregoing, the condenser is formed through the pipe plate 22 and the cooling plate 3 through the cooling sea water 6 from the film damaged portion 23a of the outlet water chamber 9 and the film damaged portion 23b of the outlet circulation water pipe 10. An electric circuit is formed through the fuselage of (2), through which the corrosion current 24 flows from the damaged film portions 23a and 23b to the plurality of throttle plates 22 and the cooling tube 3, thereby forming the damaged film ( 23a, 23b) is transferred. This phenomenon is not limited between the outlet water chamber 9 and the outlet circulating water pipe 19, and the same is true for the outlet water chamber 8 and the inlet circulating water pipe 7.

On the other hand, the above phenomenon is described in the case where the cooling tube 3 and the tube plate 22 is present as a noble metal, but the ball collector 14, the ball injection tube 18, the butterfly valve 11, When the installation portions of the thermometer 12 and the pressure gauge 13 are made of stainless steel, which is, of course, precious metal, iron, a natural potential difference occurs between the stainless steel lamp and the iron of the damaged portions 23a and 23b. Likewise, nonmetallic iron is transferred.

This phenomenon will also be described in detail with reference to FIG. In FIG. 4, the outlet circulating water pipe 10 is provided with a ball collector 14 made of a material such as stainless steel, and a ball recirculating pipe 15 is connected thereto. Accordingly, the film damaged portion of the outlet circulating water pipe 10 besides the corrosion current 24 flowing from the film damaged portion 23b of the outlet circulating water pipe 10 as described in FIG. 3 to the tube plate 22 and the cooling pipe 3. An electrical circuit is formed from the outlet circulation pipe 10 through the ball collector 14 through the cooling water 6 from 23b. As a result, the corrosion current 24 flows from the damaged film portion 23b to the ball collector 14. In this case, the damaged film 23b is spread. This phenomenon is affected by the tube plate 22 and the cooling tube 3 when the film damaged part 23b is close to the condenser 2, and when the film damaged part 23b is close to the ball collector 14, The ball collector 14 is affected. In addition, the stainless steel mentioned here is stainless steel with a stable passivation film, and as shown in FIG. 2, the potential of the stainless steel (passivation) is usually about 0 to 100 mV SCE, but if the thickness of the passivation film is sufficient, the brass side is used. It becomes a metal compared with this stainless steel (floating dynamic).

Therefore, stainless steel (floating) which does not cause abnormal phenomenon is not transferred. However, the operating conditions of the condenser 2 are changed so that the stainless steel side is made of metal by special conditions, for example, foreign matters in seawater, and during the barbering of the tube plate 22 and the aluminum brass tube of the cooling tube 3. Natural potential difference occurs, in which case stainless steel is electroplated.

This phenomenon will be described with reference to FIG. In FIG. 5, it is assumed that a part of the ball collector 14 disposed in the outlet circulating water pipe 10 becomes active and the other part is covered by the passivation film. It is assumed to be in.

The electrical circuit in this case is a ball collector 14 of stainless steel exposed from the outlet circulating water pipe 10 and through the plurality of throttle plates 22 and the cooling pipe 23 through the cooling sea water 6 of the condenser 2. It becomes a circuit through a fuselage part. Corrosion current 24 to the tube plate 22 and the cooling tube 3 flows through the area A of the ball collector 14 from the portion covered with the passive film of the ball collector 14 exposed by this circuit. The ball collector 14 of stainless steel is catered around the A area.

As a method of protecting the equipment from electrostatic phenomena in the inlet and outlet water chambers 8 and 9 and the inlet and outlet circulation pipes 7, 10, a method of flowing anticorrosive currents into the inlet and outlet water chambers 8 and 9 is provided. It is widely done. On the other hand, the same phenomenon in the ball collector 14 or the like is also carried out by preventing an electric current by flowing an appropriate anticorrosive current in the vicinity thereof.

Hereinafter, the specific method of the electric method will be described based on these measures. In FIG. 6, reference numeral 26 denotes a sacrificial anode, which is attached to generate the anticorrosive current 27.

In addition, although not shown here, the same apparatus is provided also in the entrance water chamber 8, and the same effect is acquired.

In this configuration, the corrosion current 27 flows from the sacrificial anode 26 to the plural manifold plates 22, the cooling tubes 3, and the damaged film portions 23a and 23b, and flows from the damaged film portions 23a and 23b. (24) (see Figure 3). This can prevent the film from being damaged by the damaged portions 23a and 23b. At this time, local corrosion of the tube plate 22 and the cooling tube 3 is also prevented.

In the case of performing the cathode method normally, the metal system is performed by making it into the side which is 200-250 mV beyond the natural potential of the metal. In general, the natural potential of iron in seawater is about 450-650 mV SCE as shown in Figure 2, and this sets the anticorrosive potential of iron.

In addition, the more the non-limiting side, the higher the anti-corrosion effect, but the coating material such as rubber or tar epoxy resin, which is installed on the steel surface for the anti-corrosion, has a problem that the surface deteriorates and peels off. Therefore, it is usually set in the range of -650 to -900mV SCE.

Moreover, the method as shown in FIG. 7 is also used. The difference from FIG. 6 of FIG. 7 is that the anticorrosive device 28 controls the anticorrosive potential and the current value. That is, a control electrode 29 for controlling anticorrosive potential and current value is attached to the lower part of the outlet water chamber 9. The reference electrode 29 communicates with the electrical system 29 via the potential control device 30 to detect the potential at the position where the control electrode 29 is attached and returns it to the electrical system 29. Reference numeral 36 denotes an external power supply electrode.

Other constructions are as shown in FIG. On the other hand, when the stainless steel ball collector 14 is installed in the path of the outlet circulation water pipe 10, it is necessary to prepare for the corrosion of the stainless steel. The electric system in this case is performed as follows centering on the ball collector 14.

That is, reference numeral 26 in FIG. 8 denotes a sacrificial anode, and is attached to generate the anticorrosive current 27.

In this configuration, the anticorrosive current 27 flows from the sacrificial anode 26 to the ball collector 14 and the film damaged portion 23 to extinguish the corrosion current 24 flowing from the film damaged portion 23 (see FIG. 3). Let's do it. This can prevent the film from being damaged by the damaged portion 23. At this time, local corrosion such as hole corrosion and interstitial corrosion of the ball collector 14 and corrosion of the active state are also prevented at the same time.

In addition, the method as shown in FIG. 9 is used. 9 differs from that of FIG. 8 in that a control electrode 29 for controlling anticorrosive potential and current value is attached at a position adjacent to the ball collector 14 of the outlet circulation pipe 10. The reference electrode 29 is connected to the electrical system 29 via the potential control device 30, and detects and returns the potential at the position where the reference electrode 29 is attached. Other constructions are as shown in FIG.

Next, the method of coping with the phenomenon of corrosion in the condenser composed of titanium material, which is a metal more precious than brass, will be described.

In general, such a titanium condenser is called an all- titanium condenser, but the constitution of the condenser, peripheral equipment, piping instrumentation, and the like has not changed from that shown in FIG. Typical of this type of all-titanium recuperator is used in a large-scale thermal power plant nuclear power plant, and the tube plate 22 and the cooling tube 3 are made of titanium material.

The tube plate 22 and the cooling tube 3 made of titanium material may be considered to be almost exclusively excluded if they are extremely excellent in corrosion resistance and limited to corrosion phenomenon caused by seawater itself. However, metals other than titanium are used as other sub-constituents of all titanium multipliers, and metals other than titanium are also used in peripherals, pipes, and products as described above, and are limited due to the potential difference between titanium and other metals. It is unavoidable that electric metal will generate | occur | produce in the side metal.

In addition, there is a problem in the entire titanium multiplier that it is not enough to cope with the above-described phenomena described in FIGS. 6, 7, 8, and 9, and must deal with a different way of thinking. The peculiar phenomenon such as titanium is a hydrogen embrittlement problem. This hydrogen embrittlement is a phenomenon that the metal material is brittle due to the absorption of hydrogen, and is caused when hydrogen absorption starts when the titanium material is polarized in seawater more than about -600 mV SCE. Therefore, the anticorrosion potential in the case of preventing the corrosion by the method shown in Figs. 6, 7, 8, and 9 needs to set the potential at the point where the titanium material does not generate hydrogen embrittlement.

10 shows a construction method of the electric system in all the titanium multipliers carried out through the above points. In addition, the same code | symbol is attached | subjected to the part same as the part shown in FIG. 6 and FIG. In FIG. 10, reference numeral 26 denotes a sacrificial anode. It is attached to generate the anticorrosive current 27. In the drawing, reference numeral 25 denotes a ground, and although not shown here, the same apparatus is provided in the inlet chamber 8 so that the same effect can be obtained.

In this configuration, the anticorrosive current 27 dissipates the corrosion current 24 (see FIG. 3) flowing from the sacrificial anode 26 from the tube plate 22, the cooling tube 3, and the coating damaged portions 23a and 23b. . Here, the potential at the lower part of the outlet water chamber 9 avoids the occurrence of hydrogen embrittlement of the titanium material so that it is on the side more precious than -600 mV SCE. The potential near the outlet of the outlet circulation pipe 10 is about -650 to 900 mV for iron.

Incidentally, the method of coping with the phenomenon of electroforming in the ball collector 14 of stainless steel is not changed from that described in FIG.

Moreover, the method as shown in FIG. 11 is also used. 11 differs from FIG. 10 in that the control electrodes 29a and 29b are provided at the lower part of the outlet water chamber 9 and at the ends of the condenser 2 side of the outlet circulating water pipe 10, respectively. . These control electrodes 29a and 29b are connected to the electric system 28 via the potential control devices 30a and 30b, respectively. Here, the contrast active 29a detects the potential at the lower part of the outlet water chamber 9 and returns it to the electric system 28, but the set potential in this case avoids the occurrence of hydrogen embrittlement of the titanium material, which is more precious than -600 mV SCE. I am going to be the side.

On the other hand, the control electrode 29a detects the potential near the outlet of the outlet circulating water pipe 10 and returns it to the electric system 28. In this case, the set potential is set to about -659 ~ -900mV for iron. Other constructions are as shown in FIG.

Incidentally, the method of coping with the phenomenon of electroforming in the ball collector 14 of stainless steel has not changed from that described in FIG.

As described above, in the all titanium recuperator, a sacrificial anode (10) is formed in the outlet circulating water pipe (10) in order to prevent the exposed steel surface of the coating damaged portions (23a, 23b) generated in the outlet water chamber (9) and the outlet water pipe (10). 26) and the anticorrosive current 27 flows toward the damaged film portion 23a existing in the outlet water chamber 9, for example, but in this case, the sacrificial anode 26 is extremely extreme. In the case of approaching the 9) side, the anticorrosive current 27 flows to the film damaged portion 23a and also the anticorrosive current flows into the tube plate 22 and the cooling tube 3 outside the anticorrosive object.

When the loss current flows into the tube plate 22 and the cooling tube 3, the polarization characteristics of the titanium material change depending on the magnitude of the current value, so that the titanium material exhibits a potential closer than the natural potential exhibited in the seawater. For this reason, in the lower part of the outlet water chamber 9, the electric potential becomes more inverse than the electric potential about -600 mV SCE which a titanium material produces hydrogen embrittlement.

As a countermeasure, it is conceivable to install the sacrificial anode 26 at a location far from the outlet water chamber 9. In this case, the loss current flowing through the tube plate 22 and the cooling tube 3 is significantly smaller than in the case described above, so that the potential of the lower part of the outlet water chamber 9 becomes more precious than about -600 mV SCE described above. Hydrogen embrittlement does not occur. However, the potential of this site becomes the precious side, which is the potential of the precious side at a distance other than the lower part of the outlet chamber 9 as a whole in the outlet chamber 9, for example, in the vicinity of the damaged film 23a. The anticorrosive current 27 does not flow at all.

At this time, it is considered preferable that the sacrificial anode 26 is far from the outlet chamber 9, and at the same time it is relatively easy to cope with the iron anticorrosive potential of -650 to 900 mV SCE.

However, in the vicinity of the outlet circulating water pipe 10 to which the sacrificial anodes 26 are attached, when such measures are taken, there is a possibility of causing the following problems, and thus there is no possibility of using them practically. That is, the surface of the coating material such as rubber, tar epoxy resin, etc., which is applied to the steel surface for the method of the outlet circulation pipe 10, etc., is easily deteriorated due to the anticorrosion potential and the current value which are further increased by such measures. There is a risk that these materials will peel off from the material, which is a big problem.

It is not preferable to take such an iron anticorrosive potential of -650 to -900mV SCE to the more non-limiting side because it is undesirable to the coating material side.

On the other hand, in the conventional electric method that does not give consideration to the installation place and the like of the sacrificial anode 26 as described above, it cannot be said that it truly serves as an anti-transmission role, and improvement is required.

Accordingly, an object of the present invention is to provide an electrical method of all titanium heat exchanger, which suppresses hydrogen embrittlement of titanium material used in heat exchanger and also reliably prevents corrosion of steel surface by corrosion phenomenon in the part of carbon steel used with titanium material. The present invention provides an apparatus and an electrical method thereof.

The present invention has a pair of water chambers in communication with the heat exchanger to solve the above problems, and is configured to flow the seawater as a refrigerant through the heat transfer pipe from one side of the water chamber to the other, each of the heat transfer pipes In the electrical method of the all-titanium heat exchanger, the titanium material is used together with the supporting pipe plate, and each of the chambers is made of metal material on the side that is electrically inferior to the tartan material together with the piping device connected to the chamber. And cover the area with a relatively hard insulating material so that the electrical insulation of the entire area in each of the chambers and the area of the pipes in each piping device is well retained, and the anticorrosive potential in each of the chambers and each piping device is covered. In the holding, a dry state capable of suppressing hydrogen embrittlement of the titanium material in the vicinity of the lower tube sheet in each of the chambers Further characterized in that for controlling the voltage and current value to see the potential of each of the pipe natural potential of the iron from the water at least in the vicinity of the boundary area covered by an insulating material than ruthless side in the apparatus, respectively.

In addition, the electric corrosion prevention apparatus of the all-titanium heat exchanger according to the present invention has a pair of water chambers communicating with the heat exchanger body, and is configured such that seawater as a refrigerant flows through the heat transfer pipe from one side of the water chamber to the other. The heat transfer tube uses titanium material together with the tube plate supporting the heat transfer tube, and each of the above water chambers is made of a titanium material, which is electrically connected to the water chamber, and is made of a metal material that is more electrically than the tartan material, respectively. In this case, the area is covered with a relatively hard insulating material so that the electrical insulation of the entire area in each of the chambers and the area in communication with the chambers in each piping device is well maintained, And a control electrode is provided near the boundary of the covered area by the insulating material in each of the piping devices. The potential of the method of the point electrode to an external power source to see a predetermined value characterized in that the respective equipment between a distance from each Susilo.

It has a pair of water chambers communicating with the electric heat exchanger body of the all-titanium heat exchanger according to the present invention, and is configured to flow seawater as a refrigerant through an insulated tube from one side of the water chamber to the other, and each of the heat transfer tubes Titanium material is used together with the tube plate supporting the heat-reducing tube, and each of the above water chambers has a piping device connected to the water chamber together with a piping device connected to this water chamber than the titanium material, and a metal on the side that is electrically non-titanium than the titanium material. In the electrical system of the all-titanium heat exchanger, each of which is manufactured by using a material, the region is relatively firm in insulation so that the electrical insulation is well maintained in a certain region communicating with the entire region in each chamber and the chamber in each piping system. In coating with material and holding the anticorrosive potential in each chamber and each piping system, Sacrificial potentials in the piping system are held so that the potential for inhibiting hydrogen embrittlement of the titanium material in the vicinity of the bottom of the pipe plate is held at least near the natural potential in the seawater in the vicinity of the coverage area boundary of the insulating material in the respective piping devices. A positive electrode is attached.

The electric system of the all-titanium heat exchanger according to the present invention has a pair of water chambers communicating with the heat exchanger body, and is configured to flow seawater as a refrigerant through the heat transfer pipe from one side of the water chamber to the other, An electric anticorrosion apparatus of all titanium heat exchangers produced by using a titanium material together with a supporting tube plate, and each of the above-mentioned chambers are each made of a metal material that is electrically inferior to the titanium material together with a piping device connected to the chamber. In this case, the area is covered with a relatively solid insulating material so that the electrical insulation of a certain area in communication with the entire water chamber in each chamber and the water chamber in each piping device is well retained, and the anticorrosive potential at these points is a predetermined value. Each sacrificial anode is provided within the piping system so as to be retained by It characterized.

Herein, the metal which is more inferior to the titanium material means carbon steel, and as a material of the circulating water pipe, JIS G3101, SS400 (SS41), JIS G3106, SM400 (SM41), SM490 (SM50), etc. As the material of the positive electrode, as a non-limiting metal material, for example, zinc alloy (1% or less of iron, cadmium, lead, aluminum, silicon, balance such as zinc) or aluminum alloy (1-6% zinc, 1% or less of zirconium, indium) , Iron, copper, silicon, balance aluminum).

The axial potential distribution of the circulating water pipe 10 is experimentally and interpreted according to experiment and analysis. As shown in FIG. 13, the sacrificial anode showing a potential proportional to the axial distance of the circulating water pipe 10 from the sacrificial anode 26. It was confirmed that the absolute value of the electric potential decreased as it fell from (26). This fact means that Ohm's law can be applied to the axial potential in the circulation water pipe 10.

Therefore, the following equation holds. Here, the inner diameter of the circulating water pipe 10 is D.

here

Φ _T : Titanium anticorrosive potential (VSCE)

Φ _A : potential of sacrificial anode (VSCE)

I; Anticorrosive Current (A)

: 해수의 전도율(μ/cm)

: Conductivity of sea water (μ / cm)

D: inner diameter of circulating water pipe (cm)

에 대해서는 종래 명확히 되어 있지 않았으나 발명자의 실험 해석결과 다음 값의 범위인 것이 확인되었다. 즉,According to the above formula, L ₃ when aluminum is used for the sacrificial anode is calculated. Where I,

Although it is not clear about conventionally, it was confirmed that it was the range of the following value as a result of experiment analysis of the inventor. In other words,

I

3.0 (A)1.0

I

3.0 (A)

0.05(μ/cm)0.3

0.05 (μ / cm)

Therefore, the minimum value of the attachment position of the sacrificial anode 26 becomes the following value.

-0.6(V·SCE)Φ _T

-0.6 (V, SCE)

Φ _A = -1.0 (V, SCE)

,

0.003D²(cm)로 하면 관판(22)와 냉각관(3)에 사용하는 티탄의 수소취화를 방지할 수 있다.Therefore, the distance L ₃ to the attachment position of the sacrificial anode 26

When the thickness is 0.003D ² (cm), hydrogen embrittlement of the titanium used for the tube plate 22 and the cooling tube 3 can be prevented.

That the above description can be obtained to prevent hydrogen embrittlement of the titanium results since the case of using aluminum to the sacrificial anode (26), but using the zinc potential (Φ _A) of the anodes of zinc claim is substantially the same as that of the aluminum value okay.

Range to handle the high insulating lining on the next adjacent heat exchanger circulating water pipe 10 to the L ₂ is determined in the following manner.

In this case, the potential at the position of L ₂ from the bottom of the heat exchanger needs to be equal to the anticorrosive potential of the carbon steel at -770 mV.SCE. Therefore, if we apply Ohm's law, the following equation is established.

The following equations are obtained from the above equations (1) and (3).

Where Φ _R ; Anticorrosive potential of carbon steel piping on sacrificial anode side end of highly insulating lining Φ _T -Φ _A ; Same as Equation (1).

)등에 의하지 않고, 제 14도의 순환수관(10)에서 라이닝을 행하는 범위 L₂와 희생양극(26)의 부착위치까지의 거리 L₃의 비를 구하는 것을 나타내고 있다.The formula (4) is Φ _T, Φ _A and Φ _R of the shell is determined when circulation water tube inner diameter (D), the current system (I) and the conductivity of the sea water (

The ratio of the distance L ₃ to the attachment position of the sacrificial anode 26 and the range L ₂ to which lining is performed in the circulation water pipe 10 of FIG. 14 is shown.

As above

-0.6(V·SCE)Φ _T

-0.6 (V, SCE)

-1.0(V·SCE)Φ _A

-1.0 (V, SCE)

-0.77(V·SCE)Φ _R

-0.77 (V, SCE)

If you substitute these into equation (5)

0.4L₃(cm)로 하면 탄소강제 배관의 방식이 가능해 진다.Therefore, in the circulating water pipe 10, the range of lining with high insulation is L ₂

If 0.4L ₃ (cm) is used, the type of carbon steel piping is possible.

Next, FIG. 12 shows a potential distribution at the center of the outlet water chamber and the outlet water collecting pipe obtained by experiment and analysis. In the figure, the vertical axis represents the potential of the center of the tube, and the horizontal axis represents the outlet water chamber 9 and the outlet circulation pipe 10 shown above the graph. The potential distribution is a change in the positions of the sacrificial anodes in the outlet circulation pipe 10, respectively.

In this case, it is a sacrificial anode mainly composed of zinc or aluminum, and manufactured to maintain the potential in seawater at about -100 mV SCE. The distribution curve is connected by connecting the measured potentials in the outlet water chamber (9) and the outlet circulation pipe (10). (a) (b) and (c). (A) is the potential distribution in the case where the attachment position of the sacrificial anode 26 was ideal, in this case, the potential of about -770mV SCE at the position slightly closer to the outlet chamber 9 side from the sacrificial anode 26, In the outlet water chamber 9, the potential is lower than that of -500 mV SCE. In other words, the steel surface can be easily shifted by an electric wire in the case where proper correspondence is not employed between the outlet circulation pipe 10 and the outlet water chamber 9 connected to the outlet circulating water pipe 10, which has a point that is more precious than that at about 770 mV SCE. It is entering the realm of being violated. On the other hand, the area in the outlet circulating water pipe 10 having a potential higher than that of about -770 mV SCE is an area in which the electric effect is applied, and there is little risk of transferring the steel surface.

As a result of the above experiments and analysis results, the region showing the potential on the rare side of the steel surface is less than about -770 mV SCE, which is in danger of being damaged by electrical corrosion. The region indicative of a potential more precious than about -770 mV SCE in (10) is covered. On the other hand, in areas with a potential higher than about -770 mV SCE, the corrosion resistance of the steel surface is taken into consideration, and the coating is mainly performed using a material having anticorrosive properties. In addition, the expansion joint 19 inserted into the outlet circulating water pipe 10 may be excluded from the object of the electrical system because it is originally composed of an insulating material (rubber or the like).

Next, (b) is a potential distribution diagram when the sacrificial anode 26 is closer to the outlet water chamber 9 side than in the case of (a). Compared with (a), the part showing the potential of about -770 mV is closer to the outlet water chamber 9 side.

In other words, the area closer to the outlet water chamber 9 is closer than that of the effect of the electric system, and the coverage area by the material having electrical insulation is reduced by that amount. However, the potential in the outlet water chamber 9 is significantly closer to the side compared to (a), which is -500 mV SCE, and is close to the potential -600 mV SCE involving hydrogen embrittlement of the titanium material, for example, the tube plate 22 and the cooling pipe (3). If the potential is greatly changed due to contamination, etc., and may reach the side of -6000mV, it may reach -6000mV SCE, and (b) with less margin than (a) has high risk of hydrogen embrittlement.

In contrast to (b), the potential distribution in the case where the sacrificial anode 26 is attached at a position farther from (a) is shown as (c). In contrast to (a), the potential in the outlet water chamber 9 in this case is shifted to the more precious side and becomes a potential which is not a problem at all with respect to hydrogen embrittlement of the titanium material.

However, the electric potential in the outlet circulation pipe 10 is farther from the outlet water chamber 9 when the electric potential in the outlet circulation pipe 10 is compared with (a). That is, the coverage area by the material having electrical insulation is widened by the movement of the area in which the effect of the electrical system is effective, whereas the coverage area by the anticorrosive material is narrowed.

In this way, extending the coverage area by the electrically insulating material and in other words, widening the area where the effect of the electric system is not effective, should be more careful considering the damage of the covering material in the case. In addition, there is a limit to the application of an insulating material that is economically expensive. As a result, the sacrificial anode 26 is not attached to the position where the potential distribution of (c) is shown, so that the covering region is shortened.

However, as described above, when the potential distribution is equal to (b), this time, the concern of hydrogen embrittlement of the titanium material is increased, so that (a) has a small area where the electric system does not fall, and the potential of hydrogen embrittlement of the titanium material does not occur. It can be said to be a distribution.

In another experiment and analysis, the potential of the sacrificial anode 26 was prepared so that the potential of the sacrificial anode 26 was maintained at about -1600 mV SCE in seawater using the sacrificial anode 26 containing magnesium as a main component. Using this sacrificial anode 26, it was raised to about -1600 mV SCE and the potential distribution was measured. This is the distribution curve indicated by broken lines in the figure. In contrast to (a), it is clear that the area of the effect of the electric system is wider than that of (a), but it is noticeable that the harmfulness is noticeably larger than the benefit only by increasing the potential setting.

That is, since the potential in the outlet water chamber 9 approaches -600 mV SCE, the risk of occurrence of hydrogen satellites increases and is set to the side that is higher than -1000 mV SCE, so that the insulation material is likely to peel off. Therefore, the sacrificial anode 26 preferably uses a sacrificial anode 26 composed mainly of zinc or aluminum, so that the potential of the sacrificial anode 26 is about 1000 mV SCE.

In addition, the lower limit of the anticorrosive potential is about -650mV SCE since the natural potential in seawater of iron is -450 ~ 650mV SCE.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In Fig. 14, the interior of the outlet water chamber 9 is covered with a coating material having electrical insulation, for example, a rubber 41 of a firm structure.

The lower portion of the outlet water chamber 9 has its potential more precious than -600 mV SCE, and a sacrificial anode 26 is attached to prevent hydrogen embrittlement of the titanium material. In addition, the same is covered by the High - 41 for the region of L ₃ to be communicated with the outlet Susilo 9 of the outlet circulation pipes (10). Usually, the expansion joint 19 is made of rubber. There is no exposed portion of the steel surface in the region of L ₂ .

The area other than L ₂ of the outlet circulating water pipe 10 is covered with the tar epoxy resin 42 of the coating material having the same anticorrosive property, but this part is the boundary between the rubber 41 and the tar epoxy resin 42. The potential of the sacrificial anode 26 is set in consideration of the position of the sacrificial anode 26 so that the set electric potential is set to be on a side larger than -770 mV SCE so that the steel surface is not invaded by the electroforming.

On the other hand, it is attached at a distance of L ₃ from the outlet water chamber 9 of the sacrificial anode 26. Therefore, the region of the electric scheme is the L ₁ minus L ₂ L ₃ in.

The lower potential, current value and outlet in the outlet water chamber 9 when L ₃ is about 4.8 m, the inner diameter D of the outlet circulation pipe 10 is 2.4 m, and the potential of the sacrificial anode 26 is about -1000 mV SCE. The measurement results of the potential distribution in the circulation water pipe 10 will be described.

First, the change of the electric potential of the lower part of the outlet water chamber 9 is demonstrated.

In FIG. 15, the vertical axis represents the potential of the tube center of the outlet circulation pipe 10, and the horizontal axis represents the distance from the sacrificial anode 26 to the heat exchanger side, respectively.

If L ₃ is about 4.8 (L ₂ 1D ≒ 2), that is, the potential from the sacrificial anode 26 to about 4.8 m away is indicated by a curve g and the lower potential in the outlet chamber 9 is -600 mV. It is understood that it is on the side more precious than SCE. In this case, in the range of about 4.8 m to about 3.8 m, the potential becomes more precious than -600 mV SCE, and hydrogen embrittlement of the titanium material does not occur within this range.

By the way, in Fig. 15, the case where L ₃ is about 2.4 m and the case where about 1.2 m is indicated by curves h and i. These values are 1.0 and 0.5 times the inner diameter D of the outlet circulation pipe 10.

Since the potentials of curves (h) and (i) are always higher than -600 mV SCE, hydrogen embrittlement of the titanium material occurs. Therefore, it is necessary to aim at the curve g separated | separated to the distance of 2 times with respect to the inner diameter D.

Next, the change of the current value will be described.

In FIG. 16, the vertical axis represents the current value of the sacrificial anode 26 and the horizontal axis represents the distance from the heat exchanger to the sacrificial anode, respectively. According to FIG. 16, when the distance is larger than about 4.8m, the current becomes almost constant at about 2A. Moreover, when smaller than this, a current value will rise rapidly. Next, the potential distribution in the outlet circulation pipe 10 will be described. The conditions are the same as those in FIGS. 15 and 16, but the case where the potential of the sacrificial anode 26 is about -1600 mV SCE is also shown.

In FIG. 17, the vertical axis represents the potential at the center of the outlet water pipe 10, and the horizontal axis represents the distance from the sacrificial anode 26 to the heat exchanger side, respectively.

Curve j shows the potential distribution of the outlet circulation pipe 10 when the potential of the sacrificial anode 26 is about -1000 mV SCE. The distance from the sacrificial anode 26 is less than about 2.4 m, and the potential distribution is closer than that of -770 mV SCE, and the steel surface method has a desired result. On the other hand, the excess portion (diagonal portion) becomes a potential on the side more precious than -770mV SCE, and the anticorrosive effect cannot be obtained.

In order to contrast with the curve j, the potential distribution of the center of the center of the outlet water chamber 9 and the outlet circulation pipe 10 in the case where the potential of the sacrificial anode 26 is -1600 mV SCE is indicated as the curve k.

Within about 4.1 m of the sacrificial anode 26, the potential distribution is closer than that of -770 mV SCE, and the anticorrosive effect is wider than the above potential. It is not a potential (approximately -1000 mV SCE) that is maintained at an appropriate value as shown by the curve (g) of the figure, and this cannot be dependent.

As described above with reference to FIGS. 15, 16 and 17, the anticorrosive effect is obtained when the attachment position of the sacrificial anode 26 is about 4.8 m, so that L ₂ = L ₃ -L ₁ = 4.8-2.4. = 2.4 and about 2.4 m or more becomes a coating | cover area | region by the material which has insulation in this case.

Next, a second embodiment of the present invention will be described with reference to the drawings.

In Fig. 18, the interior of the outlet water chamber 9 is covered with a coating material having electrical insulation, for example, a rubber 41 of a rigid structure. The control electrode 29a is attached to the lower part of the outlet water chamber 9, and its potential is set to a side more precious than -600 mV SCE, and the detection potential is fed back to the electric system 28 to prevent hydrogen embrittlement of the titanium material.

In addition, it is covered by the same rubber (41) about the areas of the L ₂ to be in communication with the outlet Susilo 9 of the outlet circulation pipes (10). Normal expansion joint 19 is made of rubber and the region of L _2, the exposed portion of the surface area of the river L ₂ is not present.

The area other than L ₂ of the outlet circulating water pipe 10 is covered with tar epoxy resin 42, which is a coating material having anticorrosiveness, but contrasts with the boundary between the rubber 41 and the tar epoxy resin 42 ( 29b) is installed. The setting potential of the control electrode 29b is higher than that of -770 mV SCE, and the detection potential is returned to the electric system 28 so that the steel surface is not impeded by the electroforming.

On the other hand, the external power electrode 36 controlled by the electric system 28 is attached at a distance of L ₂ from the outlet water chamber 9. Therefore, the region of the electric scheme is to remove the L ₁ L ₂ L ₃ from.

The lower potential and current value in the outlet water chamber 9 when L ₃ is about 4.8 m, the inner diameter D of the outlet circulation water pipe 10 is 2.4 m, and the potential of the external power supply electrode 36 is about -1000 mV SCE. And the measurement results of the potential distribution of the outlet circulation pipe 10.

First, the potential change of the lower part in the outlet water chamber 9 will be described.

In FIG. 19, the vertical axis represents the potential of the tube center of the outlet circulation pipe 10, and the horizontal axis represents the distance from the external power supply electrode 36 to the heat exchanger side, respectively.

If L ₃ is about 4.8 m (L ₃ / D 32), that is, the potential up to about 4.8 m from the external power electrode 36 is indicated by a curve g and the lower part in the outlet chamber 9 It is understood that the potential is on the return side rather than -600 mV SCE. In this case, in the range of about 4.8 m to about 3.3 m, the potential becomes more precious than -600 mV SCE, and hydrogen embrittlement of the titanium material does not occur within this range.

In FIG. 19, the case where L ₃ is about 2.4 m and the case where about 1.2 m is indicated by curves h and j. These values are 1.0 and 0.5 times the inner diameter d of the outlet circulation pipe 10.

Since the potentials of the curves (h) and (i) are always more inverse than -600 mV SCE, hydrogen embrittlement of the titanium material occurs. Therefore, it is necessary to make the mole curve the curve g which separated | separated up to twice the distance with respect to the inner diameter D.

Next, the change of the current value will be described.

In FIG. 21, the vertical axis represents the current value of the external power electrode 36, and the horizontal axis represents the distance from the heat exchanger to the external power electrode 36, respectively. According to FIG. 20, when the distance is larger than about 4.8m, the current becomes substantially constant at about 2A. If it is smaller than this, the current value is rapidly increased.

Next, the potential distribution in the outlet circulation pipe 10 will be described. The conditions are the same as those in FIGS. 19 and 20, but the potential of the external power supply electrode 36 is about -1500 mV SCE.

In FIG. 21, the vertical axis represents the potential at the center of the outlet circulating water pipe 10, and the horizontal axis represents the distance from the external power supply electrode 36 to the heat exchanger side, respectively.

Curve j shows the potential distribution of the outlet circulation pipe 10 when the potential of the external power supply electrode 36 is about -1000 mV SCE. Although slightly different depending on the current value, within about 2.4 m of the distance from the external power supply electrode 36 becomes the potential distribution on the side closer than -770 mV SCE, and the steel surface method has a desired result. On the other hand, the portion (diagonal portion) exceeding this becomes a potential more precious than -770mV SCE, and the anticorrosive effect cannot be obtained.

In order to contrast the curve j, the potential distribution at the center of the center of the outlet water chamber 9 and the outlet circulation pipe 10 when the potential of the external power electrode 36 is about -1500 mV SCE is indicated by the curve k. . Although slightly different depending on the current value, a distance of about 4.1 m from the external power supply electrode 36 becomes a potential distribution on the side closer than -770 mV SCE, and a corrosion protection effect has a wider range than the above potential, but this potential is in the outlet chamber 9. The lower potential is not a potential (about -1000 mV SCE) that holds an appropriate value as shown by the curve g in FIG. 19, and cannot be relied on.

As described above with reference to FIGS. 19, 20 and 21, when the attachment position of the external power electrode 36 is about 4.8 m, the anticorrosive effect is about 2.4 m, so L ₂ = L ₃ -L ₁ = 4.8- 2.4 = 2.4, and about 2.4 m or more becomes a coating | cover area with the insulating material in this case.

Next, a third embodiment of the present invention will be described with reference to the drawings.

In the present embodiment, an area other than L ₂ of the outlet circulation pipe 10 is covered with tar epoxy resin 42, which is a coating material having anticorrosive property, but with respect to the boundary between the rubber 41 and the tar epoxy resin 42. The anticorrosive potential is set to about -650mV SCE as the natural potential in seawater (-450 ~ -650mV SCE).

This results in lowering the current value by setting the potential to the inverse side and reducing the hydrogen embrittlement of the titanium material and reducing the coverage area due to the expensive rubber. It is especially suitable for making economic effects even higher.

In FIG. 22, the inside of the outlet water chamber 9 and the region of L _{2 to} which it is connected are covered with a rubber 41 having a rigid structure, as in each of the above-described embodiments, and there are no steel surface exposed portions there. . In the area is L ₂ contains an elastic joint (19).

In addition, an area other than L ₂ of the outlet circulation pipe 10 is covered by the tar epoxy resin 42. Sacrificial anode 26 is L ₁ is disposed at a position of L ₂ is removed from the L ₂ L ₃ in the repeat region is two feet in the region of the electrical system in this case.

The lower potential, current value and outlet in the outlet water chamber 9 when L ₃ is about 4.8 m, the inner diameter D of the outlet circulation pipe 10 is 2.4 m, and the potential of the sacrificial anode 26 is about -1000 mV SCE. The measurement results of the potential distribution in the circulation water pipe 10 will be described.

First, the change in the lower potential in the outlet water chamber 9 will be described.

Compared to the embodiment described earlier, the present embodiment has a tar epoxy having a shorter L ₂ covered with the rubber 41 of the rigid structure of the outlet circulation water pipe 10 and a region other than L ₂ of the outlet circulation water pipe 10. The range of L ₁ coated with the resin 42 is lengthened. Therefore, when the positions of the sacrificial anodes 26 are the same, they are almost equal to the curve g of FIG. 15.

In the case where L ₂ is about 4.8 m (L ₂ / D 즉 2), i.e., about 4.8 m away from the sacrificial anode 26, the potential becomes equal to the curve g. Therefore, although described earlier, at this time, the lower potential in the outlet chamber 9 enters the precious side rather than -600 mV SCE, so that hydrogen embrittlement of the titanium material does not occur.

Next, regarding the change of the current value, the position of the sacrificial anode 26 is the same position as that of the first described embodiment, and as described above, when the distance from the heat exchanger to the anode is about 4.8 m in FIG. Almost constant. If the distance is smaller than this, the current value is increased rapidly.

Next, the potential distribution in the outlet circulation pipe 10 will be described with reference to FIG. The potential distribution is a curve j when the potential of the sacrificial anode 26 is -1000 mV SCE. Within about 2.9m of the distance from the sacrificial anode 26, the potential distribution is closer than that of about -650mV SCE, and the steel surface method becomes a problem-free area. On the other hand, the part exceeding this part becomes more precious than about -650 mV SCE, and the anticorrosive effect cannot be obtained.

As described above with reference to FIGS. 15, 16 and 17, when the attachment position of the sacrificial anode 26 is about 4.8 m, the anticorrosive effect is about 2.9 m, so L ₂ = L ₃ -L ₁ = 4.8-2.9 It becomes = 1.9 and about 1.9 m or more becomes a coating | cover area with the material which has the electrical insulation in this case.

The set potential of the outlet circulating water pipe 10 of the present embodiment is at the limit of the residual potential in the seawater of iron, and is less precious than the -770 mV SCE of the first embodiment described above, so that reliability is somewhat impaired, but economic importance is emphasized. By this embodiment it is possible to obtain a corresponding effect.

Next, a fourth embodiment of the present invention will be described with reference to the drawings.

In this embodiment, the potential of the external power supply electrode 36 is maintained at about -700 mV SCE, which is a more precious potential than -770 mV SCE.

This is a particularly suitable method when the economic effect is further increased and lowered by setting the electric potential to the invaluable side as compared with the second embodiment described above, or lowering the current value or reducing the coverage area with expensive rubber.

In FIG. 23, as in each of the above-described embodiments, the inside of the outlet water chamber 9 and the region of L ₂ communicating therewith are covered with a solid portion 41 having a rigid structure, and there are exposed portions of the steel surface at these portions. I never do that. In the area is L ₂ contains an elastic joint (19).

In addition, regions other than L ₂ of the outlet circulation pipe 10 are covered by the tar epoxy resin 42. An external power supply electrode 36 is provided at the position of L ₃ in the covering region and the L ₁ to L ₂ drawn from the L ₃ is in the region of the electrical system in this case.

Hereinafter, the lower potential and current value in the outlet water chamber 9 when L ₃ is about 3.6 m, the inner diameter D of the outlet circulation water pipe 10 is 2.4 m, and the potential of the external power supply electrode 36 is about -700 mV SCE. And the measurement results of the potential distribution in the outlet circulation pipe 10.

First, the change of the lower potential in the outlet water chamber 9 will be described with reference to FIG. In addition, the vertical axis | shaft has shown the electric potential of the center of the tube of the outlet circulation water pipe 10, and the horizontal axis | shaft has shown the distance from the external power supply electrode 10 to the heat exchanger side, respectively.

When L ₃ is about 3.6 m (L ₂ /D≒1.5), that is, the potential up to about 3.6 m away from the external power supply electrode 36 is indicated by the curve e and at this time the outlet chamber 9 The lower potential in the metal enters the more precious side than -600 mV SCE, so that hydrogen embrittlement of the titanium material does not occur.

Curves m and n indicate potentials when L ₃ is 0.5 (L ₂ / D'2) and 0.24 m (L ₂ /D'0.1). In either case, the hydrogen embrittlement of the titanium material occurs because the side is more than -600 mV SCE. Therefore, it is necessary to separate it by the distance of 1.5 times with respect to the inner diameter D.

Next, the change in the current value will be described with reference to FIG. Here, the vertical axis represents the current value of the external power electrode 36, and the horizontal axis represents the distance from the heat exchanger to the external power electrode 36, respectively. According to Fig. 25, when the distance is larger than 3.6m, it is almost constant at the weak side of 0.2A. As a result, the current value increases rapidly when the distance decreases.

Next, the potential distribution in the outlet circulation pipe 10 will be described with reference to FIG.

In addition, the vertical axis | shaft has shown the electric potential in the center of the tube of the outlet circulation water pipe 10, and the horizontal axis | shaft has shown the distance from the external power supply electrode 36 to the heat exchanger side, respectively.

The curve (0) shows the potential distribution of the outlet circulation pipe 10 when the potential of the external power supply electrode 36 is about -700 mV SCE. Although slightly different depending on the current value, within about 1.7 m of the distance from the external power supply electrode 36 becomes the potential distribution on the side closer than that of about -650 mV SCE, and the steel surface method becomes a problem-free area. On the other hand, the portion exceeding this (the slanted portion) becomes more precious than about -650 mV SCE, and the anticorrosive effect cannot be obtained.

As described above with reference to FIGS. 24, 25 and 26, when the attachment position of the external power electrode 36 is about 3.6 m, the anticorrosive effect is about 1.7 m, so L ₂ = L ₃ -L _1. = 3.6-1.7 = 1.9, and about 1.9 m or more becomes a coating area by a material having electrical insulation in this case.

Since the set potential of the outlet circulating water pipe 10 of the present embodiment is at the limit of the natural potential in the seawater of iron and is more precious than the -770 mV SCE of the second embodiment, the reliability is somewhat impaired, but the economic importance is emphasized. By this embodiment can be obtained a corresponding effect.

In addition, with reference to FIG. 27, an embodiment different from the above embodiments will be described. In FIG. 27, the configuration of this embodiment is further advanced as shown in FIG. 23 so that the control electrodes 29a and 29b are changed from zinc to steel and the set potential is the natural potential in the seawater of iron. That is, when the reference electrode made of steel is used, when the potential near the reference electrodes 29a and 29b becomes more precious than the natural potential in the seawater of iron, the potential of the reference electrode itself is immediately detected and an anticorrosive current flows. In the case where iron becomes more than the natural potential in seawater, it is possible to immediately detect this and reduce the anticorrosive current and to accurately grasp the corrosion and corrosion state of the steel surface. In a control electrode made of a common zinc material or the like, the potential to be measured is somewhat uneven and an error is a problem. In the case of the counter electrodes of the zinc materials of the second and fourth embodiments described above, it is difficult to set the value of the set potential, for example, the time delay of the detection potential or the natural nature of the zinc material even when the set potential is -550 mV SCE. There are variations in potentials, variations due to environmental conditions, variations in potentials during zinc polarization, and errors in measurement potentials have to be taken into account. However, the use of steel counter electrodes 29a and 29b eliminates the need to worry about such errors.

In each of the embodiments described above, the area indicated by L ₂ , which electrically insulates the inner surface of the outlet circulating water pipe 10, shows an example in which a solid coating using rubber 41 is applied to the steel pipe. As shown in the figure, an area indicated by L ₂ in the purified water pipe 10 is an insulating pipe 45 made of an electrically insulating material such as vinyl chloride, plastic, synthetic rubber, or fiber reinforced plastic (FRP). Even when the circulating water pipe 10 of the steel is communicated, the same effect as that obtained when the steel pipe is coated is obtained.

According to the present invention, even when a circulation water pipe for connecting the heat exchanger composed of titanium material having excellent corrosion resistance and circulating cooling seawater is made of metal material than titanium material, the electrode excretion position and potential applied to the electrode are selected. In addition, the electric insulation coating is applied to a portion of the circulation water pipe or the like, so that the titanium material of the heat exchanger does not generate hydrogen embrittlement, and the electroforming phenomenon of the circulation water pipe is reliably prevented.

Claims (9)

It has a pair of water chambers in communication with the heat exchanger, and is configured to flow seawater through the heat pipes from one side of the water chamber to the other as a refrigerant, wherein each heat pipe uses a titanium material together with a tube plate supporting the heat pipes. In the all-titanium heat exchanger in which the respective chambers are manufactured by using a metal material which is also electrically inferior to the titanium material, together with the piping device communicating with the chambers, The area is covered with a relatively hard insulating material so that the electrical insulation of a certain area in communication with the chamber is well maintained, and near the lower part of the tube plate in each of the chambers, and near the area of the covering area by the insulating material in the respective piping devices. In addition, each control electrode is provided at the same time so that the anticorrosive potential at these points can be kept at a predetermined value. An electric system of an all-titanium heat exchanger, characterized in that a secondary power supply electrode is provided between the respective chambers at a predetermined distance. It has a pair of water chambers communicating with the heat exchanger body, and is configured to flow sea water as a refrigerant from one side of the water chamber to the other through the heat pipes. In the electrical method of the all-titanium heat exchanger, each of the chambers is produced by using a metal material on the side that is electrically inferior to the titanium material together with the piping device connected to the chamber. In order to ensure that the electrical insulation of a certain area communicating with the entire chamber and the chamber of each piping device material is well retained, the area is covered with a relatively hard insulating material and the corrosion potential in each chamber and each piping device is retained. In the vicinity of the bottom of the indoor pipe, potentials capable of suppressing hydrogen embrittlement of titanium materials are An electric anticorrosion apparatus for all titanium heat exchangers, characterized in that a sacrificial anode is attached to a piping system at least near the natural potential in seawater to cover the potential at a side closer than the natural potential in seawater. The electrical system of claim 1 or 2, wherein the external power supply electrode is installed in a piping device whose installation place is about 4.8 m from the bottom of each chamber. The method according to claim 1 or 2, wherein in covering the entire area of each of the chambers and an area of about 2.4 m from the lower part of the chamber in the piping system using an insulating material and holding the anticorrosive potential in each chamber and the piping system, All titanium is provided with a sacrificial anode in the piping system so as to hold a potential of about -600 mV SCE near the bottom of the tube in the chamber and a potential of about -770 mV SCE at a point about 2.4 m away from the bottom of each chamber. Electrical system of heat exchanger. It has a pair of water chambers communicating with the heat exchanger body, and is configured to flow sea water as a refrigerant from one side of the water chamber to the other through the heat pipes, and each heat pipe uses a titanium material together with a tube plate supporting the heat pipes. In the electric method of the all-titanium heat exchanger, the respective chambers are each made of a metal material that is electrically inferior to the titanium material together with the piping device connected to the chambers. In order to ensure that the electrical insulation of a certain area communicating with the water chambers in each piping device is well held, the area is covered with a relatively hard insulating material, and the corrosion resistance in each of the water chambers and each piping device is retained. Insulating material in each piping device has a potential capable of suppressing hydrogen embrittlement of the titanium material near the bottom of the Covering a boundary region near the electrical system, the method of the former titanium heat exchanger, characterized in that for controlling the voltage and current value to each of the iron not natural potential than the potential of the ruthless side of the water from at least by. 6. The method according to claim 5, wherein an area of about 2.4 m is covered with an insulating material throughout the respective chambers and from the lower part of the chamber in the piping system, and the corrosion resistance in each chamber and the piping system is maintained. The electric method of all titanium heat exchangers, characterized in that the voltage and current values are controlled to hold the potential of about -600 mV SCE near the bottom of the tube plate and the potential of about -770 mV SCE at about 2.4 m away from the bottom of each chamber. Way. It has a pair of water chambers communicating with the heat exchanger body, and is configured to flow sea water as a refrigerant from one side of the water chamber to the other through the insulated tube, and each of the heat transfer tubes together with the titanium plate supporting the heat transfer tubes In the electrical method of the all-titanium heat exchanger, the respective chambers are produced by using a metal material on the side that is electrically inferior to the titanium material together with the piping device connected to the chamber. Cover the area with a relatively solid insulating material so that the electrical insulation of the entire area and certain areas in communication with the water chambers in each piping system is well retained, and provide the sacrificial anodes so that the anticorrosive potential of these points can be held at a predetermined value. Of the all-titanium heat exchanger, each of which is installed in a sitter piping device at a predetermined distance from the respective chambers. Not the way the device. 8. The electrical system according to claim 7, wherein the sacrificial anode is installed in a piping device whose installation place is about 4.8 m from the lower part of each chamber. 8. The method according to claim 7, wherein the area of each chamber and the lower part of the chamber in the piping system are covered with an insulating material and the anticorrosive potential in each chamber and the piping system is maintained. The sacrificial anode is attached to the piping system so as to hold a potential of about -600 mV SCE near the bottom of the tube and a potential of about -650 mV SCE at a point about 1.9 m away from the lower part of each chamber. Electrical system.

Images