CN1035685A - The electrical corrosion protection devices and methods therefor of full-titanium heat exchanger - Google Patents
The electrical corrosion protection devices and methods therefor of full-titanium heat exchanger Download PDFInfo
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- CN1035685A CN1035685A CN89100284A CN89100284A CN1035685A CN 1035685 A CN1035685 A CN 1035685A CN 89100284 A CN89100284 A CN 89100284A CN 89100284 A CN89100284 A CN 89100284A CN 1035685 A CN1035685 A CN 1035685A
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A kind of electrical corrosion protection apparatus and method of full-titanium heat exchanger, the cooling tube of heat exchanger and supporting tube sheet thereof all adopt the titanium material, coupled water tank and circulating pipe adopt on the electrochemistry than active first metal of titanium material, the alternative anode that constitutes than active second metal of the 1st metal by on electrochemistry is set in circulating pipe, material by the electricity consumption good insulation preformance constitutes the whole medial surface of water tank and the medial surface in the certain at least zone of circulating pipe, and the current potential of control significant points, can make the titanium material of heat exchanger that hydrogen brittleness does not take place, and make the galvanic corrosion phenomenon does not take place in the circulating pipe.
Description
The present invention relates to doing with seawater in the full-titanium heat exchanger of refrigeration agent the electrical corrosion protection device and the electrical corrosion protection method thereof of the full-titanium heat exchanger that adopts for the electrocorrosion that prevents the piping arrangement that it connects.
Generally speaking, be the heat exchanger of water coolant with the seawater, for example the condenser in the generating set is extensively adopting shell-and-tube.Because the cooling tube of this kind condenser directly contacts with seawater, so cooling tube uses uncorruptible stable metal (or claiming precious metal), for example, based on the copper alloy of aluminum brass, and condenser tube sheet adopts admiraltymetal plate etc.On the other hand, condenser tank and the machine that is connected with condenser, pipe arrangement use steel.Instrumentation then uses Monel metal and stainless steel with thermowell etc.Following with reference to Fig. 1, the condenser that makes the steam recover into water in the generating set is described, and an example of machine, pipe arrangement and the instrumentation articles for use of close this condenser.
The steam 1 of discharging from steam turbine is introduced into condenser 2, in condenser 2, contacts with the surface of the many cooling tubes 3 that have cooling to flow through with seawater and is cooled, and condenses into water of condensation 5.For reusing this water of condensation for generating set, by condensate pump 4 from condenser 2 with its recovery and deliver to not shown feedwater heating apparatus.The cooling tube 3 general aluminum brass pipes that adopt of condenser 2.Refrigerated sea water 6 generally is to provide by the inlet circulating pipe of being made by the carbon steel steel plate that scribbles corrosion such as tar epoxy lacquer or coating material 7, and through inlet water tank 8, flow through the inboard of the cooling tube 3 that above-mentioned aluminum brass makes, absorb the heat of steam 1 by cooling tube 3, when temperature rises, through outlet water tank 9 and outlet circulating pipe 10, be discharged into discharge outlet (sea) again.In addition, generally speaking, on above-mentioned inlet circulating pipe 7 and outlet circulating pipe 10, be equipped with and refrigerated sea water 6 stopped and the butterfly valve 11 of switching etc., and the thermometer 12(temperature detection seat of detection, monitor temperature and pressure etc.) and pressure warning unit 13(pressure detection seat).Also be provided with the ball washing unit that the degree of cleaning of keeping cooling tube 3 medial surfaces are used.Specifically be, the cleaning of reclaiming from refrigerated sea water by ball trap 14 is imported into ball recirculation pipe 15 with ball, and be transported to ball withdrawer 17 by ball recycle pump 16, pass through ball injection tube 18 once more at there, be injected in the refrigerated sea water that flows through in the inlet circulating pipe 7, by carrying out said process repeatedly, removing attached to foreign matter of cooling tube 3 medial surfaces etc.
Again, at inlet circulating pipe 7 and inlet water tank 8, and the aspect that is connected of outlet water tank 9 and outlet circulating pipe 10, by loading onto the expansion joint that rubber is made, so that make it can absorb installation error and the infinitesimal deflection when turning round.
Also have, on inlet water tank 8 and outlet water tank 9,, vapor pipe 20 is housed and vent valve 21 is housed on this vapor pipe for exhaust.Again, symbol 22 expression tube sheets among the figure.
Be the corrosion that prevents that seawater from causing, to condenser, circulating pipe and part contact with sea water, in the japanning of the selection of material, metal covering or utilize the design aspects such as protection of corrosion coating material, careful especially.Generally speaking, corrosion phenomenon has the metal monomer generation corrosive spontaneous corrosion in sour environment, and two kinds of the electrocorrosion (hereinafter to be referred as galvanic corrosion) that produce when contacting of dissimilar metal.The corrosion speed of this galvanic corrosion is very quick, so must pay special attention to.So-called galvanic corrosion, refer to, usually, in a single day the dissimilar metal that is electrically connected then places electrolyte solution, stable (being difficult for oxidation) metal is just as negative electrode, active (easily oxidation) metal (or claiming base metal) is just as anode, it is poor to form spontaneous potential, anode metal becomes metal ion, and is free in electrolyte solution, thereby the phenomenon that is corroded of active metal.Fig. 2 has provided the spontaneous potential of metal in the seawater.Provided the spontaneous potential of 7 kinds of metals among the figure, wherein titanium is the metal of stable side, and zinc is the metal of active side.For example in seawater, the brass of stablizing side contacts with water with the iron of active side, and when brass was ined succession mutually with ferroelectric gas, because these two intermetallic spontaneous potential difference V, the iron of active side was subjected to galvanic corrosion because of this potential difference.In addition in seawater, when the iron of the stainless steel of stablizing side (passive state) with active side contact, when stainless steel (passive state) linked to each other with ferroelectric gas, owing to these two intermetallic spontaneous potential difference V, vivaciously the iron of side was subjected to galvanic corrosion.Same situation is also arranged in other metallic combination, and two intermetallic spontaneous potential differences are big more, and the development of galvanic corrosion phenomenon is obvious more.Again, the active side VSCE of transverse axis current potential represents saturated calomel current potential.
Above-mentioned phenomenon also can take place in the sea water system of generating set.For example, in heat exchanger, between the exposing metal of the instrumentation articles for use of employed cooling tube, strainer, valve, thermowell etc., might produce galvanic corrosion.In addition, also following situation may take place with above-mentioned materials.That is, the medial surface of piping arrangement class has been coated the corrosion lacquer or has been coated coating material in order to prevent the corrosion on steel surface on the steel surface, so that its not direct and contact with sea water.Yet, in case for a certain reason, coating or be damaged by clad can, the steel surface is exposed in the seawater, above-mentioned stable metal material links to each other with the electric property in the steel of active metal material surface, and then because the spontaneous potential of these two metals is poor, the steel surface of active side just is subjected to galvanic corrosion.Just, for example, when the cooling tube of above-mentioned condenser and condenser tube sheet 22 use aluminum brass pipe and admiraltymetal plate respectively, because inlet and outlet water tank 8,9 and inlet and outlet circulating pipe 7,10 are generally made by steel plate, so steel plate becomes the metal of active side.
Implemented the corrosion enamelled coating on why above-mentioned entrance and exit water tank 8,9 and the entrance and exit circulating pipe 7,10 or coating material is exactly for above-mentioned reasons, in case but these enamelled coatings or lining position are damaged because of the mobile etc. of construct bad and seawater, come out in steel surface as base material, then as previously mentioned, because the spontaneous potential between brass and the iron is poor, the steel face of the iron of active metal is subjected to galvanic corrosion.
Below, describe this phenomenon in detail with reference to accompanying drawing.
Suppose among Fig. 3 that tunicle pars affecta 23a is arranged on the outlet water tank 9 of water cooler 2, on outlet circulating pipe 10, tunicle pars affecta 23b is arranged also.Therefore, outside the steel surface of tunicle pars affecta 23a, 23b is exposed to., make condenser 2 by basis etc. and ground connection 25 here, on the outlet circulating pipe 10, also pipe arrangement etc. and ground connection 25 in supporting by piping arrangement or the soil.Therefore form one from the tunicle pars affecta 23a of outlet water tank 9 and the tunicle pars affecta 23b of outlet circulating pipe 10, by refrigerated sea water 6, through tube sheet 22 and cooling tube 3, arrive the electric loop of the brass of condenser 2 again, thereby, corrosion current 24 flows to condenser tube sheet 22 and cooling tube 3 from tunicle pars affecta 23a, 23b, and the result is that tunicle pars affecta 23a, 23b are by galvanic corrosion.Certainly, this phenomenon is not limited to export between water tank 9 and the outlet circulating pipe 10, and the situation of inlet water tank 8 and inlet circulating pipe 7 is also identical.
Above-mentioned phenomenon is to narrate as the situation that stable metal exists with regard to cooling tube 3 and tube sheet 22.In addition, when taking-up portion of the ball trap 14 shown in Fig. 1, ball injection tube 18, butterfly valve 11, thermometer 12 and pressure warning unit 13 etc. is made of stainless steel more stable than iron etc., it is poor to produce spontaneous potential between the iron of these stainless steels etc. and tunicle pars affecta 23a, 23b, with above-mentioned the same, the active metal is that iron is subjected to galvanic corrosion.
Referring again to Fig. 4 about this phenomenon is elaborated.Among Fig. 4, be provided with the ball trap made from materials such as stainless steels 14 in the outlet circulating pipe 10, ball recirculation pipe 15 joins therewith.Therefore, except illustrated at Fig. 3 the sort of from the outlet circulating pipe 10 tunicle pars affecta 23b to tube sheet 22, cooling tube 3 mobile corrosion currents 24, also form a tunicle pars affecta 23b in addition from outlet circulating pipe 10, by refrigerated sea water 6, through ball trap 14, arrive the electric loop of outlet circulating pipe 10 again.Thereby corrosion current 24 flow to ball trap 14 from tunicle pars affecta 23b, and the result is in this case, and tunicle pars affecta 23b is also by galvanic corrosion.When tunicle pars affecta 23b when the condenser 2, this phenomenon is subjected to the influence of tube sheet 22 and cooling tube 3, and when the close ball trap 14 of tunicle pars affecta 23b, this phenomenon is subjected to the influence of ball trap 14.In addition, described here stainless steel is meant the stainless steel with stable pure state tunicle, and as shown in Figure 2, the current potential of stainless steel (pure state) is generally about 0-100mVSCE, if above-mentioned pure state tunicle has thickness sufficient, then brass is more active than stainless steel (pure state).
Therefore, only otherwise error state (ERST) takes place, stainless steel (pure state) is not touched by electricity just can.But, when the operating condition of condenser changes, be in special state, for example because the foreign matter etc. in the seawater when making stainless local surfaces become active condition, the stainless steel side becomes active side, and it is poor to produce spontaneous potential between the aluminum brass pipe of yellow steel plate of the naval of tube sheet 22 and cooling tube 3, and this moment, stainless steel was subjected to galvanic corrosion.
With reference to Fig. 5 this phenomenon is described.Suppose that in Fig. 5 the part that is located at the ball trap 14 in the outlet circulating pipe 10 becomes active condition, and other parts are covered by the pure state tunicle.And hypothesis at this moment, and the zone that active condition occurs is arranged in the A place of figure.
Electric loop under this situation is from outlet circulating pipe 10, flows to expose stainless ball trap 14, again by refrigerated sea water 6, through condenser tube sheet 22 and cooling tube 23, arrives the body of condenser 2.Therefore, corrosion current 24 is from the part that is covered by the pure state tunicle of the ball trap 14 of exposure, and the A place through ball trap 14 flows to tube sheet 22, cooling tube 3, and the result is that in the case, stainless ball trap 14 is the center with the A place, by galvanic corrosion.
As the galvanic corrosion phenomenon that prevents in above-mentioned inlet and outlet water tank 8,9 and inlet and the outlet circulating pipe 7,10,, extensively adopting the corrosion protection electric current mobile method in inlet and outlet water tank 8,9 that makes with the method for protection equipment.On the other hand, for the same phenomenon of ball trap 14 grades, also taked to pass in its vicinity suitable corrosion protection electric current to prevent the method for galvanic corrosion.
Below be the center with these measures, the concrete grammar of electrical corrosion protection is described.Among Fig. 6, symbol 26 expressions substitute anode, and this installs for corrosion protection electric current 27 takes place.
In addition, in inlet water tank 8, also be provided with same device (not shown), and make it can obtain same effect.
In the above-described configuration, corrosion protection electric current 27 flows to condenser tube sheet 22, cooling tube 3 and tunicle pars affecta 23a, 23b from substituting anode 26, sees Fig. 3 from the effusive corrosion current 24(of tunicle pars affecta 23a, 23b) eliminated.Therefore can prevent the galvanic corrosion of tunicle pars affecta 23a, 23b.In addition, at this moment can also prevent simultaneously the locality corrosion of tube sheet 22 and cooling tube 3.
When generally carrying out cathodic protection, more tend to the about 200～250mV of active side, just can carry out the corrosion protection of this metal by making its spontaneous potential than this metal.Generally speaking, in the seawater spontaneous potential of iron as shown in Figure 2, be about-450～-650VSCE, from then on can set the corrosion protection current potential of iron.
Tending to active side more also claims low-priced side or downside corrosion protection result high more, but, if set too close active side for, then for corrosion protection surface deterioration just can take place and problem such as peel off at the coating material of the surface coated rubber of steel, tar epoxy etc., so can not set too close active side for.Therefore, generally be set at-650～-scope of 900mVSCE.
Perhaps also can adopt method shown in Figure 7.The difference of Fig. 7 and Fig. 6 is in the bottom of outlet water tank 9, the reference electrode 29 of control corrosion protection current potential and current value to be installed.This reference electrode 29 links to each other with electrical corrosion protection device 28 by potential controlling apparatus 30, detect the current potential of installation position of reference electrode 29 after, feed back to alternative electrode 26.Other formation effect is same as shown in Figure 6.
In addition, when being provided with stainless ball trap 14 in the road of outlet circulating pipe 10, be necessary stainless galvanic corrosion phenomenon is taken measures.Electrical corrosion protection under this situation is the center with ball trap 14, following carrying out.
Specifically be that in Fig. 8, symbol 28 expressions substitute anode, install in order to produce corrosion protection electric current 29.
In the above-described configuration, the corrosion protection electric current flows to ball trap 14, tunicle pars affecta 23 from substituting anode 28, and 23 effusive corrosion current 24(see Fig. 3 from the tunicle pars affecta) eliminated.Therefore, can prevent the galvanic corrosion of tunicle pars affecta 23.In addition, can also prevent simultaneously the locality corrosion of the pitting attack, crevice corrosion and so on of ball trap 14 this moment, and the corrosion of active condition.
Also can use method shown in Figure 9.The difference of Fig. 9 and Fig. 8 is, at the position adjacent with ball trap 14 of outlet circulating pipe 10, the reference electrode 34 of control corrosion protection current potential and current value is installed.This reference electrode 34 links to each other with electrical corrosion protection device 33 by potential controlling apparatus 35, feeds back after detecting the current potential of installation site of reference electrode 34 again.Other formation effect is same as shown in Figure 8.
Illustrate below that adopting than brass more stable metal in the major portion of the condenser 2 that was made of the brass based material in the past is in the condenser that constitutes of titanium material, is which kind of method to tackle corrosion phenomenon with.
The condenser that this kind is made of the titanium material is commonly referred to as full titanium condenser, the formation and the same invariably part shown in Figure 1 of condenser and equipment on every side thereof, pipe arrangement and instrumentation articles for use etc.The typical case of the full titanium condenser of this kind is applied to large-scale thermal power station and nuclear power station, and its tube sheet 22 and cooling tube 3 usefulness titanium materials are made.
The tube sheet 22 that is made of the titanium material and the solidity to corrosion of cooling tube 3 are fabulous, if only limit to the corrosion phenomenon that seawater itself causes, then these parts almost can not considered.Yet, other component part materials as full titanium condenser, also using titanium metal in addition, in addition, equipment, pipe arrangement and goods etc. around it, also using as previously mentioned than the active metal of titanium, because the potential difference of titanium material and other metals, galvanic corrosion can take place in the metal of active side inevitably.
And for full titanium condenser, it is not enough only tackling in the simple galvanic corrosion phenomenon described in Fig. 6, Fig. 7, Fig. 8 and Fig. 9, also has the necessary problem that solves with other method.Here it is, and distinctive phenomenon such as titanium material is the problem of hydrogen brittleness.So-called hydrogen brittleness refers to owing to absorbed hydrogen, the phenomenon that metallic substance becomes fragile, this causes from following reason, promptly the titanium material in seawater, in case polarization into about than-more active the side of 600mVSCE, hydrogen absorbs and just can begin.Therefore, when preventing galvanic corrosion with Fig. 6, Fig. 7, Fig. 8 and method shown in Figure 9, the corrosion protection current potential must be set at the current potential that the hydrogen brittleness place can not take place.
Figure 10 has provided the constructional method according to electrical corrosion protection in the full titanium condenser of above-mentioned some embodiment.Among the figure, the part identical with Fig. 6 and part shown in Figure 8 put on identical symbol.Among Figure 10, symbol 26 expressions substitute anode, and this installs in order to make it corrosion protection electric current 27 takes place.Again, symbol 30 expression ground wires among the figure.In addition, also be provided with same device (not shown) in the inlet water tank 8, can obtain same effect.
In the above-described configuration, corrosion protection electric current 27 flows to tube sheet 22, cooling tube 3 and tunicle pars affecta 23a, 23b from substituting anode 26, sees Fig. 3 from the effusive corrosion current 24(of tunicle pars affecta 23a, 23b) eliminated.For avoiding titanium material generation hydrogen brittleness, and use the more close stable side of current potential ratio-600mVSCE of saliva case 9 bottoms here.Again, near the current potential the outlet of outlet circulating pipe 10 is object with iron, set into about-650～-900mV.
In addition, tackle the method for the galvanic corrosion phenomenon in the stainless ball trap 14, and utilize the same invariably part described in Fig. 8.
Can also adopt method shown in Figure 11.The difference of Figure 11 and Figure 10 is, in the bottom of outlet water tank 9 and condenser 2 side ends of outlet circulating pipe 10, is respectively equipped with reference electrode 39a, the 39b of control corrosion protection current potential and current value.These reference electrodes 39a, 39b by potential controlling apparatus 40a, 40b, link to each other with electrical corrosion protection device 38 respectively.Here, reference electrode 39a detects and feeds back to electrical corrosion protection device 38 to the current potential of outlet water tank 9 bottoms, the setting current potential of this moment is configured to the more stable side of ratio-600mVSCE (also claiming your side or high side) under the prerequisite of avoiding titanium material generation hydrogen brittleness.
On the other hand, reference electrode 39a detects and feeds back to electrical corrosion protection device 38 near the current potential 10 outlets of outlet circulating pipe.The setting current potential of this moment is an object with iron, be set at-650～-900mVSCE about.Other formation effect is same as shown in Figure 10.
Again, the method that tackles the galvanic corrosion phenomenon in the stainless ball trap 14 with utilize the described same invariably part of Fig. 9.
As mentioned above, for full titanium condenser, in order to prevent to export water tank 9 and export the tunicle pars affecta 23a of water pipe 10 generations, the galvanic corrosion of 23b place exposed steel face, in outlet circulating pipe 10, alternative anode is set, make corrosion protection electric current 27 play the flow direction from here and for example export the tunicle pars affecta 23a that exists in the water tank 9, but close at this field boundary, when alternative anode 26 is too near to outlet water tank 9 sides, when corrosion protection electric current 27 flows to tunicle pars affecta 23a, do not belong in the tube sheet 22 of corrosion protection object and the cooling tube 3 and flow into corrosion protection electric current 27 yet.
In a single day this loss electric current flows into tube sheet 22 and cooling tube 3, and the just change with the size of current value of the polarization characteristic of titanium material is so the titanium material presents the current potential of more being partial to active side than the spontaneous potential in seawater.Therefore, in the bottom of outlet water tank 9, current potential become than the current potential of titanium material generation hydrogen brittleness promptly about-600mVSCE more be partial to active side.
For preventing above-mentioned situation, can consider alternative anode 26 is arranged on away from the position that exports water tank 9.At this moment, the loss electric current that flows to tube sheet 22 and cooling tube 3 compared with the above case will reduce significantly, and the current potential of outlet water tank 9 bottoms more is partial to stable side than above-mentioned pact-600mVSCE, and the titanium material hydrogen brittleness can not take place.But the current potential at so-called this position becomes to stablize side, from the whole inside of outlet water tank 9, just is meant all distant places except that outlet water tank 9 bottoms, and current potential becomes more stable side, and for example near tunicle pars affecta 23a, just basic no corrosion protection electric current 27 flows through.
At this moment, suppose may make substitute anode 26 away from outlet water tank 9 in, the corrosion protection current potential of iron promptly-650～-900mVSCE sets more active side for, then it is generally acknowledged and handle than being easier to, be ideal.
But, when taking this kind measure near the outlet circulating pipe of being installed at alternative anode 26 10, again following problem might take place, so the possibility of no practical application.Promptly, the coating material surface of the rubber that is covered with on the steel surface for the corrosion protection that exports circulating pipe 10 grades, tar epoxy etc., because because of further corrosion protection current potential and the current value that increases of above-mentioned measure, and make the easier development of deterioration, exist these materials to peel off the danger on steel surface, this will become very big problem.
Like this, merely make the corrosion protection current potential-650--900mVSCE of iron more be partial to active side, can make coating material side generation unfavorable condition, and improper.
In addition as previously mentioned, in to the existing electrical corrosion protection method that the necessary considerations of shortage such as position are set that substitutes anode 26, existence can not be called and really help preventing the galvanic corrosion part, requires all improvement.
Therefore, the objective of the invention is to, a kind of electrical corrosion protection device and electrical corrosion protection method thereof of full-titanium heat exchanger are provided, they can suppress the hydrogen brittleness of the employed titanium material of heat exchanger, and the carbon steel that can prevent from reliably to use simultaneously with titanium material part is corroded because of galvanic corrosion phenomenon steel surface.
The invention provides a kind of electrical corrosion protection device of full-titanium heat exchanger, in this device, the have cooling tube that seawater flows through and a pair of tube sheet that supports this cooling tube of heat exchanger all adopt the titanium material, the a pair of water tank that links to each other with each tube sheet reaches the circulating pipe that links to each other respectively with this water tank and adopts than titanium material more active the 1st metallic substance on electrochemistry, be provided with respectively in the circulating pipe by the constituent material alternative anode that more active the 2nd metallic substance constitutes on electrochemistry than these circulating pipes, it is characterized in that, at least the medial surface in certain zone in the circulating pipe that All Ranges in the water tank reaches with water tank links to each other, be to adopt the material that the good electrical insulativity is arranged to constitute, simultaneously, be L when establishing from the connection portion of water tank and circulating pipe to alternative anodic distance
3When the internal diameter size of cm, circulating pipe was Dcm, alternative anodic was provided with the position and is defined in L
3〉=0.003D
2(cm) in the scope, and when the connection portion with water tank and circulating pipe is a benchmark, establishing the circulating pipe length that medial surface at least has an electrical insulating property is L
2During cm, the medial surface at least in the circulating pipe is that the scope dictates that adopts the material that electrical insulating property is arranged to constitute the zone is L
2〉=0.4 L
3(cm).
The invention provides a kind of electrical corrosion protection device of full-titanium heat exchanger, in this device, the have cooling tube that seawater flows through and a pair of tube sheet that supports this cooling tube of heat exchanger all adopt the titanium material, the a pair of water tank that links to each other with each tube sheet reaches the circulating pipe that links to each other respectively with water tank and adopts than titanium material more active the 1st metallic substance on electrochemistry, be provided with respectively in the circulating pipe by the constituent material alternative anode that more active the 2nd metallic substance constitutes on electrochemistry than these circulating pipes, it is characterized in that, the medial surface at least in certain zone is to adopt the material that the good electrical insulativity is arranged to constitute in the circulating pipe that All Ranges in the water tank reaches with water tank links to each other, simultaneously, offer and substitute the anodic current potential, can make near the maintenance in the interior tube sheet bottom of each water tank can suppress the current potential of the hydrogen brittleness of titanium material, and can make medial surface at least in the circulating pipe is to adopt near the boundary portion in the zone that material that the good electrical insulativity is arranged constitutes, and keeps at least the current potential than the more active side of spontaneous potential of the 1st metallic substance in the seawater.
The invention provides a kind of electrical corrosion protection method of full-titanium heat exchanger, in this method, have the cooling tube of heat exchanger of the cooling tube that flows through seawater and a pair of tube sheet that supports this cooling tube and all adopt the titanium material, the a pair of water tank that links to each other with each tube sheet reaches the circulating pipe that links to each other respectively with this water tank and adopts than titanium material more active the 1st metallic substance on electrochemistry, in circulating pipe, be provided with respectively by the constituent material alternative anode that more active the 2nd metallic substance constitutes on electrochemistry than these circulating pipes, control offers these alternative anodic current potentials to carry out the corrosion protection of water tank and circulating pipe, it is characterized in that, make the medial surface at least in certain zone in the circulating pipe that All Ranges reaches with water tank links to each other in the water tank keep excellent electric insulating, control simultaneously offers and substitutes the anodic current potential, make near the current potential that remains on the hydrogen brittleness that can suppress the titanium material tube sheet bottom of each water tank, and make the boundary vicinity in the zone of the maintenance good electrical insulativity in the circulating pipe, keep at least current potential than the more active side of spontaneous potential of the 1st metallic substance in the seawater.
Secondly, also affirm the axial Potential distribution of circulating pipe 10, as according to experiment with analyze, then example is such as shown in Figure 13, represented current potential and the direction of principal axis that follows ring water pipe 10 are from substituting the far and near proportional of anode 26, and it is far away more to leave alternative anode 26, and the absolute value of current potential reduces more.This means on the axial current potential in circulating pipe 10 and can be suitable for ohm's law.Therefore following formula is set up.In addition, the internal diameter of circulating pipe 10 as D
φ in the formula
T: the protection against corrosion current potential (VSCE) of titanium
φ
λ: substitute anodic current potential (VSCE)
I: anticorrosion current (A)
δ: seawater conductivity (v/cm)
D: circulating pipe internal diameter (cm)
According to following formula, carry out L to using aluminium to substitute the anodic occasion
3Calculating.Here be not clear and definite originally about I, δ, but, confirm as the value of following scope, promptly according to experiment of the present invention and analytical results
1.0≤I≤3.0（A）
0.03≤δ≤0.05（v/cm）
Therefore, the minimum value of the installation site of alternative anode 9 is as follows.
Work as φ
T〉=-0.6(VSCE)
φ
λ＝-1.0（V·SCE）
XD
2＝0.003·D
2（cm）
Therefore, be taken as L if will substitute the installation site of anode 26
3〉=0.03D
2(cm), just can prevent to be used for the hydrogen embrittlement of the volt of tube sheet 22 and cooling tube 3.
Above-mentioned explanation is about aluminium being used for substitute the occasion of anode 26, yet promptly uses zinc, yet learns because zinc system substitutes anodic current potential φ
λRoughly the same with the potential value of aluminium, so also can obtain the result of the same hydrogen attack embrittlement that prevents titanium.
Next, on the close circulating pipe 10 of heat exchanger, apply the range L of the plating of high-insulativity
2, decide by following formula.
Be necessary in the automatic heat-exchanger bottom surface to be L this moment
2The position protection against corrosion current potential-770mVSCE of its current potential and carbon steel is equated.Therefore, as ohm's law of same use, then following formula is set up.
With above-mentioned formula (1), (3) obtain following formula.
(φ
T－φ
R)/(φ
T-φ
λ) = (L
2)/(L
3) ……（4）
L
2= (φ
T－φ
R)/(φ
T-φ
λ) ·L
3……（5）
In the formula, φ
R: the protection against corrosion current potential that adopts the alternative anode one side end carbon steel pipe arrangement of high-insulativity plating.
φ
T, φ
λ: identical with formula (1)
In the formula, formula (4) expression, in case determined the value of φ, φ and φ, just can be not according to the circulating pipe inside diameter D, the heat transfer rate δ of anticorrosion current I and seawater obtains the ratio of the installation site L of the range L that applies plating on circulating pipe 10 and alternative anode 26.With above-mentioned the same, order
φ
T≥-0.6（V·SCE）
φ
λ＝-1.0（V·SCE）
φ
R≤-0.77（V·SCE）
With these substitution formulas (5),
＝0.4·L
3（cm）
Therefore, if make the range L of the plating of the high insulating property that is applied on the circulating pipe 10
2〉=
0.4L
3(cm), then make the protection against corrosion of carbon steel system pipe arrangement become possibility.
Effect
Figure 12-1 expression is by experiment and analysis outlet water tank of trying to achieve and the Potential distribution that exports the circulating pipe centre.Among the figure, ordinate zou is represented the current potential of tube hub, and X-coordinate is represented the position by outlet water tank shown in the figure (being Figure 12-2) that is positioned on this figure 9 and outlet circulating pipe 10.Potential distribution is exactly the situation when outlet circulating pipe 10 interior alternative anodic positions are changed.At this moment, be to adopt with zinc or aluminium alternative anode as major ingredient, this anode be manufactured and make its current potential in seawater keep being about-1000mVSCE, current potential in outlet water tank 9 that records and the outlet circulating pipe 10 is linked up, be expressed as curve (a) respectively, (b), (c).At first, Potential distribution when (a) installation site of the alternative anode 26 of expression is ideal scenario, in this occasion, in position from the close slightly outlet water tank of alternative anode 26 9 one sides, current potential is about-770mVSCE, in outlet water tank 9, become the more stable current potential of ratio-500mVSCE, just, about-770mVSCE as dividing point, is being shown that the occasion that can not obtain suitable corresponding relation than the outlet circulating pipe 10 and the connected outlet water tank 9 of its more stable current potential is vulnerable to the erosive zone with regard to having entered the steel surface because of galvanic corrosion.On the other hand, show than be about-fields in the outlet circulating pipe 10 of the more active current potential of 770mVSCE are exactly the field that anti-galvanic corrosion effect can reach, the danger of generation galvanic corrosion is few on the steel surface.
According to above-mentioned experiment and analytical results, demonstration has because of the weather scope of current potential of the dangerous more stable side of pact-770mVSCE of galvanic corrosion than steel surface, adopts the special excellent material of electrical insulation properties to be covered to showing the zone than outlet water tank 9 and outlet circulating pipe 10 Nei Yue-current potential that 770mVSCE is more stable.On the other hand,, consider and suppress the steel surface corrosion that the main material with non-corrosibility that adopts is covered to showing zone than the more active current potential of pact-770mVSCE.In addition, to being installed to the expansion joint 19 that outlet circulating pipe 10 gets on,, can not be considered as the object of anti-galvanic corrosion because the original insulativity material of just using constitutes (rubber etc.).
In addition, (b) be Potential distribution when substituting anode 26 than more close outlet water tank 9 one sides of the occasion of (a).(a) compare, show to be about-more close outlet water tank 9 one sides in place of 770mV current potential.Just, therefore more close outlet water tank one side in anti-galvanic corrosion effect zone in one's power, can make to adopt to have the area decreases that the electrical insulating property material is covered.Yet, current potential in the outlet water tank 9 with pass across-(a) of 500mVSCE compare, then significantly be partial to an active side, and the current potential-600mVSCE that has hydrogen brittleness near the titanium material, if owing to the pollution of tube sheet 22 and cooling tube 3 etc. makes the current potential noticeable change, thereby the occasion of active side be partial to, perhaps can reach-600mVSCE, so (a) compare, less (b) in the leeway danger of its hydrogen brittleness thus is also higher, thereby is difficult to be used.
In addition and (b) opposite, (c) expression is installed in the Potential distribution during distant positions more than (a) to alternative anode 26.When comparing with (a), the current potential in the outlet water tank 9 of this moment is more to a stable side shifting, and current potential at this moment becomes concerning the hydrogen embrittlement of titanium material unquestionable fully.Yet, the current potential in the outlet circulating pipe 10, with (a) when comparing, show to be about-place of the current potential of 770mVSCE, from outlet water tank 9 look become farther.Just, because anti-galvanic corrosion effect can reach moving of zone, make to have enlarged, otherwise the feasible zone that is covered with anticorrosive has narrowed down with having the electric insulating quality material zone that is covered.Like that, make with the be covered expansion in field of electrically insulating material, in other words, the inaccessible zone of anti-galvanic corrosion effect institute is enlarged, this way is if consider coating material just in case damaged, then must be more prudent.In addition, use the expensive insulativity material aspect of price also limited economically.Consequently, show the Potential distribution position of (c), can not install and substitute anode 26, it should be configured to make the lining zone more to shorten.But, as described above, when Potential distribution becomes (b) like that the time, so next will increase to the worry of the hydrogen brittleness of titanium material.Therefore we can say, (a) is that anti-galvanic corrosion zone can't be obtained is few, and the Potential distribution of titanium material hydrogen brittleness can not take place.
On the other hand, in other experiment and analyzing, the current potential that substitutes anode 26 is about-1000mVSCE from the current potential of above-mentioned experiment, use with the alternative electrode 26 of magnesium as major ingredient, and make its current potential in seawater is maintained at about-1600mVSCE, use to substitute anode, make it to rise to pact-1600mVSCE, and measured Potential distribution.This is exactly a distribution curve as shown in phantom in FIG..And if (a) correlated words, be apparent that anti-galvanic corrosion effect zone in one's power further enlarges than (a), but if the potential setting value is become greatly, then harm is bigger significantly than interests.Just, the current potential in the outlet water tank 9 is almost approaching-600mVSCE, when the danger that causes hydrogen brittleness uprises more, because of setting the more active side of ratio-1000mVSCE for, so the peeling off of easy generation insulating material.Therefore, preferably substitute anode 26 and uses with zinc or the aluminium alternative anode 26 as major ingredient, the current potential of the alternative anode 26 of order is about-1000mVSCE.
In addition since the spontaneous potential of iron in seawater be-450～-650mVSCE, the lower limit of corrosion protection current potential should be pact-650mVSCE.
Embodiment
Followingly one embodiment of the invention are explained with reference to accompanying drawing.
In Figure 14, the inside of outlet water tank 9 is with having the coating material of electrical insulating property, for example has that the rubber 31 of strong construction is covered.Bottom for this outlet water tank 9 makes its current potential be in the also stable side of ratio-600mVSCE, and the hydrogen embrittlement that makes it not cause the titanium material is installed like that and substituted anode 26.In addition, the L that is connected with outlet water tank 9 at outlet circulating pipe 10
2The zone also be covered with same rubber 31.Usually, expansion joint 19 is to make with rubber, so the steel surface portion that is not exposed in the zone of L.
In addition, at the L that exports circulating pipe 10
2Zone in addition, be to be used as to have non-corrosibility coating material tar epoxy 32 and cover, yet boundary part for rubber 31 and this tar epoxy 32, make the setting voltage of this part become the also active side of ratio-700mVSCE, and the position of alternative anode 26 is provided with considering under the situation that does not cause the steel surface to suffer erosion because of electrocorrosion.
On the other hand, being installed in alternative anode 26 from exporting water tank 9 is L
3Distance.Therefore, the subject area of anti-electrocorrosion just becomes from L
3In deduct L
2After L
1.
Below to L
2Be about 4.8m, the inside diameter D of outlet circulating pipe 10 is 2.4m, the current potential that substitutes anode 26 is about-the outlet water tank 9 of the occasion of 1000mVSCE in the current potential of bottoms, the measurement result of the Potential distribution in current value and the outlet circulating pipe 10 is narrated.
Potential variation to outlet water pipe 9 bottoms describes earlier.
In Figure 15, ordinate zou represents to export the current potential at the pipe center of circulating pipe 10, and X-coordinate is represented from substituting the distance that anode 26 heat exchanger one side is gone.
At L
3Be about 4.8m(L
3/ D ≒ 2) occasion, promptly the current potential till substituting anode 26 about 4.8m is appreciated that with curve (g) expression the current potential of bottom in the outlet water tank 9 is in the stable side of ratio-600mVSCE.In this occasion, in the scope from about 4.8m to about 3.3m, current potential is in the stable side of ratio-600mVSCE, and in this scope, the phenomenon of the hydrogen brittleness of titanium material can not take place.
Yet in Figure 15, L
3The occasion that is about 2.4m, and in the occasion of about 1.2m, represent with curve (h) with (i) respectively.In addition, the ratio of the inside diameter D of the relative outlet of these values circulating pipe 10 is respectively 1.0 times and 0.5 times.
Because curve (h) and current potential (i) are in the active side than 600mVSCE usually, thereby the hydrogen brittleness phenomenon of titanium material can occur.Therefore be necessary to leave apart from (g) till being 2 times for relative inside diameter D as target.
Below, the variation of current value is described.
In Figure 16, ordinate zou represents to substitute the current value of anode 26, and X-coordinate represents that automatic heat-exchanger rises to substituting the distance that anode 26 ends.If according to Figure 16, when distance went out about 4.8m greatly, then electric current was approximately less than 2 ampere-hour almost fixed.And when distance diminished than this, then current value sharply rose.Then, the Potential distribution in the outlet circulating pipe 10 is described.In addition, the condition all occasion with Figure 15 and Figure 16 is identical, yet the current potential of also having represented alternative anode 26 is about-occasion of 1600mVSCE.
In Figure 17, ordinate zou represents to be in the current potential at the tube hub place that exports circulating pipe 10, and X-coordinate is represented from substituting the distance of anode 26 towards heat exchanger one side.
Curve (j) is illustrated in the current potential that substitutes anode 26 and is about-Potential distribution of the outlet circulating pipe 10 of the occasion of 1000mVSCE.When the distance that substitutes anode 26 is in 2.4m, form the more active Potential distribution of ratio-770mVSCE, can obtain desirable result to the protection against corrosion on steel surface.On the other hand, surpass the part (oblique line is represented part) of this distance,, can not obtain anticorrosion ability because of becoming the also stable current potential of ratio-770mVSCE.
For and curve (j) compare, curve (k) is illustrated in the current potential that substitutes anode 26 and is about-Potential distribution of the outlet water tank 9 of the occasion of 1600mVSCE and the tube hub of outlet cyclic water tank 10.
When the distance that substitutes anode 26 is in 4.1m, because of Potential distribution than-more active the side of 770mVSCE, therefore can reach anticorrosion ability than above-mentioned current potential wider scope, yet, this current potential be not as shown in (g) among Figure 15 like that, the current potential that can use bottom in the saliva case 9 remains the current potential of appropriate value (approximately-1000mVSCE), so can not rely on it.
More than, according to Figure 15,16 and 17, because when the installation site that substitutes anode 26 was about 4.8m, the scope that obtains anticorrosion ability was about 2.4m, therefore become L=L-L=4.8-2.4=2.4, becoming for this reason more than about 2.4m, the usefulness of occasion has the zone that the insulativity material is covered.
Next, with reference to accompanying drawing the second embodiment of the present invention is described.
In Figure 18, outlet water tank 9 is inner with the coating material with electrical insulating property, and for example firmly the rubber of structure is covered.Bottom at this outlet water tank 9 is installed with reference electrode 39a, and its potential setting than-a side that 600mVSCE is also stable, is made and detects current potential and feed back to anti-electroerosion apparatus in order to avoid cause the hydrogen brittleness of titanium material.In addition, the L that is connected with outlet water tank 9 for outlet circulating pipe 10
2The zone carry out coated with rubber 31 too.Usually, expansion joint 19 is to make with rubber, therefore at L
2The zone do not have the expose portion on steel surface.
In addition, the L of outlet circulating pipe 10
2Zone in addition is to use the tar epoxy 32 of the coating material with non-corrosibility to cover, yet the boundary of rubber 31 and this tar epoxy 32 is provided with reference electrode 39b.The potential setting of this reference electrode 39b than-also active the side of 770mVSCE, is made to feed back in the anti-electroerosion apparatus 38 with reference to current potential and goes, in order to avoid the steel surface can weather because of galvanic corrosionization.
On the other hand, being installed in the alternative electrode of controlling with anti-electroerosion apparatus 38 26 from the outlet water tank is L
3Distance.Therefore the subject area of anti-electrocorrosion becomes from L
3In deduct L
2L
1
Below at L
3Be about 4.8m, the inside diameter D of outlet circulating pipe 10 is 2.4m, the current potential that substitutes anode 26 is about-the outlet water tank 9 of the occasion of 1000mVSCE in the measuring result of Potential distribution in current potential, current value and the outlet circulating pipe 10 of bottoms narrate.
Potential variation to bottom in the outlet water tank 9 describes earlier.
In Figure 19, ordinate zou represents to export the current potential of the tube hub of circulating pipe 10, and X-coordinate is represented from substituting the distance of anode 26 towards heat exchanger one side.
At L
3Be about 4.8m(L
3/ D ≒ 2) occasion Zi substituting the current potential of anode 26 till the place of leaving about 4.8m with curve (g) expression, can be regarded as the current potential that exports water tank 9 interior bottoms and is in the also stable side of ratio-600mVSCE exactly.In this occasion, about scope from 4.8m to about 3.3m, current potential is in the also steady side of ratio-600mVSCE, and the hydrogen brittleness of titanium material can not take place in this scope.
Yet, in Figure 19, curve (h) and (i) represent that respectively L is about the occasion of 2.4m and 1.2m.In addition, the inside diameter D of the relative outlet of these values circulating pipe 10 is 1.0 times and 0.5 times.
Owing to make curve (h) and current potential (i) often be in the also active side of ratio-600mVSCE, thereby can produce the hydrogen embrittlement of titanium material.Therefore (g) till being necessary the relative inside diameter D of distance is 2 times is as target.
Variation to current value describes below.
In Figure 20, ordinate zou represents to substitute the current value of anode 26, and X-coordinate is represented the distance till automatic heat-exchanger arrives alternative anode 26.According to Figure 20, when distance greatly when going out about 4.8m, electric current is then to be slightly less than 2 amperes and almost fixed.In addition, when the distance less than this moment, current value sharply rises.
Then, the Potential distribution in the outlet circulating pipe 10 is described.In addition, condition is with the same in the occasion of Figure 19 and Figure 20, but the current potential of also having represented alternative anode 26 is about-occasion of 1500mVSCE.
In Figure 21, ordinate zou represents to export the current potential of the tube hub of circulating pipe 10, and X-coordinate is represented from substituting the distance of anode 26 towards heat exchanger one side.
Curve (j) is illustrated in the current potential that substitutes anode 26 and is about-Potential distribution of the outlet circulating pipe 10 of the occasion of 1000mVSCE.Though according to the difference of current value and slightly variant, make when the distance that substitutes anode 26 is being about in the 2.4m, Potential distribution is in the also active side of ratio-770mVSCE, can obtain desirable result aspect the protection against corrosion on steel surface.On the other hand, surpass these part (part that oblique line is represented), be in the also stable Potential distribution of ratio-770mVSCE, just can not obtain etch-proof effect.
For and curve (j) contrast, represented with curve (k) to be about-the outlet water tank 9 of the occasion of 1500mVSCE and export the Potential distribution of the tube hub of circulating pipe 10 at the current potential that substitutes anode 26.Though because of current value has more or less difference, yet, leave and substitute the anodic distance in 4.1m, then its Potential distribution is than-more active the side of 770mVSCE, make corrosion protection result can reach the scope wider than above-mentioned current potential, but this current potential can not used the current potential of bottoms in the saliva case 9 and be remained on suitable current potential (pact-1000mVSCE), therefore can not rely on it as (g) expression among Figure 19.
More than, according to Figure 19,20 and 21, because when the installation site that substitutes anode 26 was about 4.8m, the scope that can obtain corrosion protection result was about 2.4, so become L=L-L=4.8-2.4, more than 2.4m, the usefulness that is exactly this occasion has the zone that the insulativity material covers.
Then the third embodiment of the present invention is described with reference to accompanying drawing.
In the present embodiment, the L of outlet circulating pipe 10
2Zone in addition is to be used as the tar epoxy 32 with corrosion coating material to cover, and for rubber 31 with the boundary part of tar epoxy 32, make the corrosion protection current potential be the spontaneous potential of iron in seawater (level 450-650mVSCE), therefore with the corrosion potential setting about spontaneous potential upper limit pact-650mVSCE.This is the embodiment that wants by narrating relatively at first, with potential setting in a stable side, current value is descended, in addition, with the potential setting of water tank 9 bottoms in a stable side, make the hydrogen brittleness that can not produce the titanium material fully, and then reduce to adopt zone that high price rubber covers etc., particularly suitable way when further improving economical effectiveness.
In Figure 22, the same with the various embodiments described above, outlet water tank 9 L inner and that link to each other therewith zones cover with the rubber 31 of solid structure, do not have the expose portion on steel surface in these places.In addition, comprise expansion joint 19 in the L zone.
In addition, the zone beyond the L of outlet circulating pipe 10 covers with tar epoxy 32, and alternative anode 26 is arranged on L in this overlay area
3The position on, from L
3In deduct L
2After L
1Become the subject area of the anti-galvanic corrosion of occasion for this reason.
Below, to L
3Be about 4.8m, the inside diameter D of outlet circulating pipe 10 is 2.4m, the current potential that substitutes anode 26 is about-the outlet water tank 9 of the occasion of 1000mVSCE in the current potential of bottoms, the measurement result of the Potential distribution in current value and the outlet circulating pipe 10 describes.
Potential variation to bottom in the outlet water tank 9 describes earlier.The embodiment of present embodiment and initial narration compares, and makes partial L with the outlet circulating pipe 10 of rubber 31 coverings of solid structure
2Shorten, export the L of circulating pipe 10 with the conduct of tar epoxy 32 coverings
2The L in zone in addition
1Scope elongated, therefore, be identical occasion in the position that substitutes anode 26, big to identical with the curve (g) of Figure 15.
At L
3Be about 4.8m(L
3/ D ≒ 2) occasion, just leaving and substituting the current potential that anode 26 is about till 4.8 the place is identical current potential with curve (g).Therefore, before narrated, therefore the hydrogen brittleness of titanium material can not take place because the current potential of outlet water tank 9 interior bottoms enters the stable side of ratio-600mVSCE in this moment yet.
Next, variation about current value is, the position that cause substitutes anode 26 is identical position with the embodiment that narrated previously, as previously mentioned, in Figure 16, be about the occasion of 4.8m in the distance of very ending from heat exchanger Zhiyang, current value is to be slightly less than 2 amperes and almost fixed.In addition, when the distance than this hour, current value will sharply rise.
Below, with reference to Figure 17 the Potential distribution in the outlet circulating pipe 10 is described.Potential distribution will become the current potential that substitutes anode 26 for shown in the curve (j) of-1000mVSCE occasion like that.Leave substitute anode 26 distance in 2.9m, its Potential distribution becomes and is in the also active side of ratio-650mVSCE, the corrosion protection that this zone becomes the steel surface is the zone of no problem roughly.Surpass on the other hand will become and stablize a side of one than pact-650mVSCE, and can not obtain corrosion protection result in this part.
More than, according to Figure 15,16 and 17, because when the installation site that substitutes anode 26 is about 4.8m, the scope of the corrosion protection result that obtains is about 2.9m, become L=L-L=4.8-2.9=1.9, more than about 1.9m, the usefulness that becomes this occasion has the zone that the electrical insulating property material covers.
The setting current potential of the outlet circulating pipe 10 of present embodiment is to be on the boundary of the spontaneous potential of iron in seawater, since become than the initial embodiment that narrated-a side that 770mVSCE is stable, make reliability that reduction be arranged slightly, yet, occasion paying attention to economy can obtain corresponding effects from present embodiment.
Then, with reference to accompanying drawing fourth embodiment of the invention is described.
In the present embodiment, make the current potential that substitutes anode 26 remain on the also stable current potential pact-700mVSCE of ratio-770mVSCE.
This is to want by comparing with above-mentioned second embodiment, in a high side, electric current is descended, and then reduces and adopt when the measures such as overlay area of rubber further improve economical effectiveness at high price, the method for particularly suitable.
In Figure 23, the same with the various embodiments described above, the inside of outlet water tank 9 and the L that links to each other therewith
2The zone cover with the rubber 31 of solid structure, do not have the expose portion on steel surface in these places.In addition, at L
2The zone comprise expansion joint 19.
In addition, the L of outlet circulating pipe 10
2Cover with tar epoxy 32 with exterior domain, be arranged on L in this overlay area substituting anode 26
3The position on, from L
3In deduct L
2After L
1Become the subject area of the anti-galvanic corrosion of occasion for this reason.
Below, to L
3Be about 3.6m, the inside diameter D of outlet circulating pipe 10 is 2.4m, the current potential that substitutes anode 26 is about-the outlet water tank 9 of the occasion of 700mVSCE in the current potential current value of bottoms and the measurement result of the Potential distribution in the outlet circulating pipe 10 describe.
With reference to Figure 24 the potential variation of bottom in the outlet water tank 9 is described earlier.The current potential of the tube hub of ordinate zou outlet circulating pipe 10 among the figure, X-coordinate is represented from substituting the distance that anode 26 goes to heat exchange one side.
At L
3Be about 3.6m(L
3/ D=1.5) occasion, just to the current potential till substituting the place that anode 26 is about 3.6m with curve (e) expression, at this moment, because the current potential of bottom enters the also stable side of ratio-600mVSCE in the outlet water tank 9, so the hydrogen brittleness phenomenon of titanium material does not take place.
In addition, curve (m) and (n) be to represent L respectively
3Be 0.5m(L
3/ D ≒ 0.2) and 0.24m(L
3The current potential of occasion/D ≒ 0.1) is because for arbitrary occasion all is to be in the also active side of ratio-600mVSCE, so the hydrogen embrittlement of titanium material can take place.Therefore, being necessary to make the relative inside diameter D of the distance of leaving is 1.5 times.
Then, with reference to Figure 25 the variation of current value is described.Ordinate zou represents to substitute the current value of anode 26, and X-coordinate represents that automatic heat-exchanger is to substituting the distance that anode 26 ends.If according to Figure 25, when distance became big than 3.6m, current value was substantially maintained fixed to be slightly less than 0.2 ampere.In addition, when distance diminished than this, current value just sharply rose.
Below, with reference to Figure 26 the Potential distribution in the outlet circulating pipe 10 is described.
Among the figure, ordinate zou represents to export the current potential of the tube hub of circulating pipe 10, and X-coordinate represents to substitute the distance that electrode 26 heat exchanger one side is gone.
The current potential that curve (o) expression substitutes anode 26 is about-Potential distribution of the outlet circulating pipe 10 of 700mVSCE occasion.Though because of current value difference more or less, yet the distance that substitutes anode 26 certainly is in about 1.7m the time, Potential distribution is in a side also lower than pact-650mVSCE, thereby becomes the roughly unchallenged zone of corrosion protection on steel surface.On the other hand, surpass this part (oblique line part), owing to become the also stable side of ratio-650mVSCE, thus can not obtain corrosion protection result.
More than, according to Figure 24,25 and 26, when being about 3.6m owing to the installation site that substitutes anode 26, the scope that can obtain corrosion protection result is about 1.7m, so become L
2=L
3-L
1=3.6-1.7=1.9, therefore, the usefulness of occasion has the zone that the electrical insulating property material covers with regard to becoming for this reason more than about 1.9m.
The setting current potential of the outlet circulating pipe 10 of present embodiment is to be on the boundary of the spontaneous potential of iron in seawater, since become than above-mentioned second embodiment-a side that 770mVSCE is also stable, make reliability that reduction be arranged slightly, yet, may obtain corresponding effect according to present embodiment paying attention to the economy occasion.
In addition, with reference to Figure 27, the embodiment different with the various embodiments described above described.In Figure 27, the composition of present embodiment is to make than more going a step further of representing in Figure 23, and with reference to electrode 44a, 44b becomes steel by the zinc material, and making it set current potential is the spontaneous potential of iron in seawater.Just, occasion at the reference electrode that uses steel, when reference electrode 44a, near the current potential the 44b become than the also stable side of the spontaneous potential of iron in seawater, detect the current potential of reference electrode itself immediately, the corrosion protection electric current is flow through, on the other hand, than the also active occasion of the spontaneous potential of iron in seawater, detect this current potential immediately, it is possible allowing the corrosion protection electric current that flows through reduce, and has the advantage that can correctly grasp steel surface corrosion and corrosion protection state.And how much have deviation, thereby produce error problem with the current potential that the reference electrode of common Zinc material system is measured.Adopt the occasion of the reference electrode of zinc material at the above-mentioned second and the 4th embodiment, place also be difficult to decision on what kind of numerical value setting current potential actually, for example, even place setting current potential-occasion of 550mVSCE, also can produce the time lag of detecting current potential, the deviation that has zinc material spontaneous potential in addition, the deviation that produces because of envrionment conditions, and the potential error during zincode etc., thereby the essential error of considering to measure current potential, and by using steel reference electrode 44a, 44b has not just worried such error.
In the various embodiments described above, make the inner face of whole outlet circulating pipes 10 become electrical isolation, and use L
2The zone of expression is to be expressed as the example that adopts rubber 31 such firm materials to be covered on steel pipe, and is such as shown in figure 28 conversely, using L
2Even the zone in the circulating pipe 10 of expression makes the insulation pipe arrangement 45 that for example is made of polyvinyl chloride, plastics, synthetic rubber or fibre reinforced plastics, steel circulating pipe 10 is linked to each other with it, also can obtain and the effect same when on steel pipe, being covered.
Simple declaration to accompanying drawing.
Fig. 1 is the figure that the coupled piping system of expression condenser is formed, Fig. 2 is the performance chart of the relevant spontaneous potential of various metals in seawater of expression, Fig. 3 to Fig. 5 is respectively the mode chart that the galvanic corrosion phenomenon in the cold device that rises is described, Fig. 6 to Figure 11 is respectively the mode chart of the electric erosion protection system in the traditional condenser of expression, Figure 12 is the potential image of explanation effect of the present invention, Figure 13 is the equi-potential distribution line chart of explanation effect of the present invention, Figure 14 is the mode chart of expression one embodiment of the invention, Figure 15 to Figure 17 is for illustrating the line chart of the effect of Figure 14 respectively, Figure 18 is the mode chart of expression second embodiment of the invention, Figure 19 to Figure 21 is for illustrating the line chart of the effect of Figure 18 respectively, Figure 22 is the mode chart of expression third embodiment of the invention, Figure 23 is the mode chart of expression fourth embodiment of the invention, Figure 24 to Figure 26 is for illustrating the line chart of the effect of Figure 23 respectively, Figure 27 is the mode chart of expression another other embodiment of the present invention, and Figure 28 is the mode chart of expression another other embodiment of the present invention.
2 is condenser, and 3 is cooling tube, and 7,10 is circulating pipe, and 8,9 is water tank, and 22 is tube sheet, and 26 for substituting anode, and 31 is rubber, and 39a, 39b are reference electrode, and 45 are the insulation pipe arrangement.
Claims (6)
1, a kind of electrical corrosion protection device of full-titanium heat exchanger, in this device, have the above-mentioned cooling tube of heat exchanger of the cooling tube that seawater flows through and a pair of tube sheet that supports this cooling tube and all adopt the titanium material, the a pair of water tank that is connected with above-mentioned each tube sheet reaches the circulating pipe that links to each other respectively with this water tank and adopts than above-mentioned titanium material active the 1st metallic substance on electrochemistry, in above-mentioned circulating pipe, be provided with respectively by the constituent material alternative anode that active the 2nd metallic substance constitutes on electrochemistry than these circulating pipes, it is characterized in that, the medial surface at least in certain zone is to adopt to have the material of good electrical insulativity to constitute in the above-mentioned circulating pipe that All Ranges in the above-mentioned water tank reaches with above-mentioned water tank links to each other, simultaneously, be L when establishing from the connection portion of above-mentioned water tank and above-mentioned circulating pipe to above-mentioned alternative anodic distance
3Cm, when the internal diameter size of above-mentioned circulating pipe was Dcm, above-mentioned alternative anodic was provided with the position and is defined as L
3〉=0.003 D
2(cm) scope, and when the connection portion with above-mentioned water tank and above-mentioned circulating pipe is a benchmark, the above-mentioned circulating pipe length of medial surface with electrical insulating property is made as L at least
2During cm, the medial surface at least in above-mentioned circulating pipe is that to adopt the above-mentioned material that electrical insulating property arranged to constitute regional scope dictates be L
2〉=0.4 L
3(cm).
2, a kind of electrical corrosion protection device of full-titanium heat exchanger, in this device, have the above-mentioned cooling tube of heat exchanger of the cooling tube that flows through seawater and a pair of tube sheet that supports this cooling tube and all adopt the titanium material, a pair of water tank that is connected with above-mentioned each tube sheet and the circulating pipe that links to each other with this water tank respectively adopt than above-mentioned titanium material active the 1st metallic substance on electrochemistry, in above-mentioned circulating pipe, be provided with respectively by the constituent material alternative anode that more active the 2nd metallic substance constitutes on electrochemistry than these circulating pipes, it is characterized in that, the medial surface at least in certain zone is to adopt to have the material of good electrical insulativity to constitute in the above-mentioned circulating pipe that All Ranges in the above-mentioned water tank reaches with above-mentioned water tank links to each other, simultaneously, offer above-mentioned alternative anodic current potential, can make near the current potential that remains on the hydrogen brittleness that can suppress the titanium material the above-mentioned tube sheet bottom in above-mentioned each water tank, and can make medial surface at least in the above-mentioned circulating pipe is to adopt the material that the good electrical insulativity is arranged to constitute the boundary vicinity in zone, and maintenance is at least than the current potential of the more active side of spontaneous potential of above-mentioned the 1st metallic substance in the seawater.
3, press the electrical corrosion protection device of claim 1 or 2 described full-titanium heat exchangers, it is characterized in that, at least the medial surface of above-mentioned circulating pipe is to adopt certain zone that material constituted that the good electrical insulativity is arranged, be all to adopt the material that the good electrical insulativity is arranged, constitute above-mentioned circulating pipe itself.
4, by the electrical corrosion protection device of claim 1 or 2 described full-titanium heat exchangers, it is characterized in that, be provided with the reference electrode that is installed in above-mentioned water tank and the above-mentioned circulating pipe respectively and controls above-mentioned alternative electrode with reference to their detection current potential.
5, a kind of electrical corrosion protection method of full-titanium heat exchanger, in the method, have the above-mentioned cooling tube of heat exchanger of the cooling tube that flows through seawater and a pair of tube sheet that supports this cooling tube and all adopt the titanium material, the a pair of water tank that is connected with above-mentioned each tube sheet reaches the circulating pipe that links to each other respectively with this water tank and adopts than above-mentioned titanium material active the 1st metallic substance on electrochemistry, in above-mentioned circulating pipe, be provided with respectively by the constituent material alternative anode that active the 2nd metallic substance constitutes on electrochemistry than these circulating pipes, control offers these alternative anodic current potentials, thereby carry out the corrosion protection of above-mentioned water tank and circulating pipe, it is characterized in that, make the medial surface at least in certain zone in the above-mentioned circulating pipe that All Ranges reaches with above-mentioned water tank links to each other in the above-mentioned water tank keep excellent electric insulating, simultaneously, control offers above-mentioned alternative anodic current potential, make near the current potential that remains on the hydrogen brittleness that can suppress the titanium material the above-mentioned tube sheet bottom in above-mentioned each water tank, and make the boundary vicinity in the zone that maintains the good electrical insulativity in the above-mentioned circulating pipe, keep at least current potential than the more active side of spontaneous potential of above-mentioned the 1st metallic substance in the seawater.
6, by the electrical corrosion protection method of the described full-titanium heat exchanger of claim 5, it is characterized in that, offer above-mentioned alternative anodic current potential, is to control with reference to the detection current potential that is installed in the reference electrode in above-mentioned water tank and the above-mentioned circulating pipe respectively.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6717/88 | 1988-01-14 | ||
| JP63006717A JPH07110999B2 (en) | 1988-01-14 | 1988-01-14 | Circulating water system anticorrosion equipment using seawater |
| JP90221/88 | 1988-04-14 | ||
| JP63210501A JPH0261079A (en) | 1988-08-26 | 1988-08-26 | Electrolytic protection device for full-titanium heat exchanger |
| JP210501/88 | 1988-08-26 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1035685A true CN1035685A (en) | 1989-09-20 |
| CN1014806B CN1014806B (en) | 1991-11-20 |
Family
ID=26340911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 89100284 Expired CN1014806B (en) | 1988-01-14 | 1989-01-14 | Apparatus and method for electrical anti-corrosion of total-titanium heat-exchanger |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1014806B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110846666A (en) * | 2019-12-11 | 2020-02-28 | 苏州热工研究院有限公司 | Condenser cathodic protection mechanism and condenser cathodic protection potential monitoring system |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1072280C (en) * | 1997-06-03 | 2001-10-03 | 福建炼油化工有限公司 | Method for preventing carbon-steel cooling apparatus from corrosion by sea water and apparatus thereof |
-
1989
- 1989-01-14 CN CN 89100284 patent/CN1014806B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110846666A (en) * | 2019-12-11 | 2020-02-28 | 苏州热工研究院有限公司 | Condenser cathodic protection mechanism and condenser cathodic protection potential monitoring system |
| CN110846666B (en) * | 2019-12-11 | 2024-04-05 | 苏州热工研究院有限公司 | Condenser cathode protection mechanism and condenser cathode protection potential monitoring system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1014806B (en) | 1991-11-20 |
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