JP2003294199A - Alternative corrosion prevention method of thermal spray coating of vaporizer and vaporizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alternative corrosion prevention method of thermal spray coating of a vaporizer and the vaporizer wherein corrosion is prevented at a low cost in a short period of working time and without damaging a tube or the like due to heat stress. <P>SOLUTION: The vaporizer 1 is equipped with a lower header 2, a plurality of tubes 3 and an upper header 4, and vaporizes LNG supplied from a delivery port 5 of the lower header by heat exchanging when passing it through the tube, and delivers it from a delivery port 6. In the alternative corrosion prevention method of thermal spray coating of the vaporizer where corrosion prevention by the thermal spray coating as a sacrifice anode is applied to the surface, corrosion prevention protection potential is maintained by sticking a thin board- like sacrifice anode tape on the predetermined position of the vaporizer when the thermal spray coating is exhausted. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vaporization device alternative corrosion protection method for a vaporizer and a vaporizer.

[0002]

2. Description of the Related Art Conventionally, natural gas, which is a clean energy that emits less carbon dioxide that causes global warming by 30 to 40% less than coal or petroleum, has been attracting attention.

[0003] When this natural gas is transported by a tanker or stored in a tank, a method of liquefying it has been conventionally used to reduce its volume. This is because the volume when the natural gas is liquefied is about 1/600 of the volume in the gas state, which is very advantageous in terms of space.

Liquefied natural gas (hereinafter referred to as "LNG")
Keeps a liquefied state in an ultra-low temperature environment of minus 162 ° C., and returns to a gas state when the temperature is raised. When supplying to a consumer, it is necessary to return LNG to gas, and this LNG is vaporized in a vaporizer.

A vaporizer that has been conventionally used is one in which LNG is passed through a plurality of aluminum tubes.
LNG by heating the tube with seawater
To vaporize. In this way, the vaporizer is always exposed to seawater, which makes it necessary to perform anticorrosion treatment on the vaporizer.

Conventionally, as the anticorrosion treatment, a vaporizer, that is, an aluminum tube, an upper header and a lower header which also support the tube are made of aluminum by spraying an alloy of aluminum and zinc, and A sprayed coating was formed on the surface, and corrosion protection was performed by a sacrificial anode method using this sprayed coating as a sacrificial anode.

However, when the vaporizer subjected to the anticorrosion treatment using the thermal spray coating as a sacrificial anode is continuously operated, the thermal spray coating on the part exposed to seawater is consumed and the anticorrosion effect cannot be obtained. come.

Therefore, conventionally, when the sprayed coating of the vaporizer has been consumed, it has been necessary to re-spray the sacrificial anode on the worn portion of the sprayed coating in order to maintain the anticorrosion potential.

As a method of preventing re-spraying of the sacrificial anode, a method of locally installing a sacrificial anode piece near the lower header of the vaporizer has been proposed.

[0010]

However, the conventional method has the following problems.

That is, in the case of the method of re-spraying the sacrificial anode on the exhausted portion of the sprayed coating on the surface of the vaporizer described above,
There is a problem that sandblasting and re-spraying work are required on the site where the vaporizer is installed, and these works require a large amount of money and a long working time, which is costly.

In the case of locally installing the sacrificial anode piece in the vicinity of the lower header of the vaporizer described above, the heat insulation of the upper surface of the lower header due to the fact that the anode piece is installed in the lower header may affect each portion. There is a concern that thermal stress may be applied and damage such as tube cracking may occur.

The present invention has been made in view of the above points, and it is inexpensive, requires only a short period of work, and can perform corrosion protection without fear of damage to tubes or the like due to thermal stress. It is an object to provide a method and a vaporizer.

[0014]

In order to achieve the above object, the present invention has a lower header, a plurality of tubes, and an upper header, and LNG supplied from a supply port of the lower header is supplied to the tube. A vaporizer that is vaporized by heat exchange when passing through and is delivered from the outlet of the upper header, in a spray coating alternative anticorrosion method of a vaporizer that has been subjected to corrosion protection by a spray coating as a sacrificial anode on its surface, When the thermal spray coating is exhausted, a thin plate sacrificial anode tape is attached to a predetermined position of the vaporizer to maintain the anticorrosion potential.

Further, the present invention has a lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube. In the vaporizer delivered from the outlet of the, in the spray coating alternative anticorrosion method of the vaporizer, the surface of which is protected by a spray coating as a sacrificial anode, when the spray coating is consumed, the lower header is It is characterized in that the anticorrosion potential is maintained by winding a thin plate sacrificial anode tape.

The present invention further includes a lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube. In the vaporizer delivered from the delivery port of, in the spray coating alternative anticorrosion method of the vaporizer, the surface of which is protected by a spray coating as a sacrificial anode, when the spray coating is consumed, the lower part of the tube It is characterized in that the anticorrosion potential is maintained by winding a thin plate-shaped sacrificial anode tape around.

Also, the present invention has a plurality of tubes having a lower header and fins and an upper header, and when LNG supplied from a supply port of the lower header is passed through the tubes, heat is exchanged and vaporized. A vaporizer delivered from the outlet of the upper header, in the spray coating alternative anticorrosion method of the vaporizer, the surface of which is protected by a spray coating as a sacrificial anode, when the spray coating is exhausted, It is characterized in that the anticorrosion potential is maintained by attaching a thin plate-shaped sacrificial anode tape to the fins.

Further, the present invention is characterized in that a band is fixed when the sacrificial anode tape is attached to the fin.

The present invention is also characterized in that rivets are fixed when the sacrificial anode tape is attached to the fins.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an example of a vaporizer according to the present invention.

As shown in FIG. 1, the vaporizer 1 includes a lower header 2, a plurality of hollow tubes 3, and
It has an upper header 4, a supply port 5 for supplying LNG to be vaporized, and a supply port 6 for supplying vaporized natural gas. Further, the tube 3 is provided with fins 3a for enhancing heat dissipation.

In the present embodiment, the material of each member of the vaporizer 1 is made of aluminum, and an alloy of aluminum and zinc is sprayed on its surface to form a sprayed coating as a sacrificial anode.

Such a sacrificial anode (also called galvanic anode)
Examples of are as follows. In the present invention, a suitable one can be appropriately selected from these sacrificial anodes in view of the relationship between the protected food material and its surrounding environment. Aranod (registered trademark): An aluminum alloy anode that has been globally recognized for its excellent performance. As a specific application, for example, it is applied to a harbor steel structure or a marine structure requiring a life of several years to several tens of years, and is suitable for corrosion protection in seawater. Suspension node: An aluminum anode containing only non-polluting elements for corrosion protection of stainless steel water heaters.
Specific applications include the use of titanium and duplex stainless steel for the heat exchanger thin tubes and tube sheets, and for reducing corrosion in stainless steel water chambers, that is, when the material to be protected is titanium or stainless steel. Suitable as a galvanic anode. Magnode (registered trademark): A magnesium alloy anode having the most base potential among various galvanic anodes. As a specific application, it is often used for corrosion protection of underground steel pipes, tank outer surfaces, etc., and is particularly suitable for use in soil or water with high resistivity, and in the case of underground installation, a special backfill around use. Zinnode (registered trademark) ... A zinc alloy anode having high current efficiency. It is most suitable for the corrosion protection of the inner surface of ship ballast tanks, and it also has an inhibitor effect by the eluted zinc ions. It also produces a small amount of hydroxide, and is also used for corrosion protection of heat exchangers and submarine pipes. Ferranod (registered trademark): Made of pure iron, which has the most noble potential in galvanic anodes, and is used for corrosion protection of metals showing relatively noble values such as copper alloys. It is most suitable for corrosion protection of heat exchangers made of copper alloy and titanium tubes. It provides longer term corrosion protection than other types of galvanic anodes. It is also used as an electrode for iron ion generation.

Returning to the explanation of FIG. 1, the carburetor 1 is used for LN.
When vaporizing G, first, LNG is supplied from the supply port 5, and seawater is sprinkled on the entire vaporizer 1.

The LNG extending from the supply port 5 to the entire inside of the lower header 2 further passes through a plurality of tubes 3,
During this time, the LNG exchanges heat with the seawater outside the tube 3 and is vaporized to become a gas state, that is, natural gas, and is then delivered to the outside from the delivery port 6 via the upper header 4.

In the vaporizer 1 to which the seawater is sprayed in this way, the sprayed coating is largely consumed mainly in the lower portion of the tube 3 and the lower header 2. Therefore, it is necessary to use a sprayed coating alternative corrosion protection for maintaining the corrosion protection potential.

Now, a first embodiment of the method for preventing corrosion by spray coating of a vaporizer according to the present invention will be described with reference to FIG.

FIG. 2 is a perspective view showing the lower portion of the vaporizer subjected to the anticorrosion treatment according to the first embodiment of the spray coating alternative anticorrosion method for the vaporizer according to the present invention.

In FIG. 2, reference numeral 7 denotes a sacrificial anode tape, which can be made of any of the above-mentioned materials that can be used as the sacrificial anode, and is formed into a thin plate shape.

In the first embodiment, the sacrificial anode tape 7 is wound around the lower header 2 as shown in FIG. At the time of this winding, it is preferable to use an adhesive containing a conductive substance. In the present embodiment, the sacrificial anode tape 7 can maintain the anticorrosion potential.

According to this method, there is no need for conventional work such as sand blasting or re-spraying, and since it is only necessary to wind the sacrificial anode tape 7, it is possible to cope with the problem at low cost and in a short period of time. Further, according to the sacrificial anode tape 7, tube cracking due to thermal stress unlike the conventional case does not occur.

Next, with reference to FIG. 3, a second embodiment of the method for preventing corrosion by spray coating of a vaporizer according to the present invention will be described.

FIG. 3 is a perspective view showing the lower portion of the vaporizer subjected to the anticorrosion treatment according to the second embodiment of the alternative method of corrosion protection for a thermal spray coating of a vaporizer according to the present invention.

In FIG. 3, reference numeral 8 is a sacrificial anode tape, and like the sacrificial anode tape 7 shown in FIG. 2, as the material thereof, a material that can be used as the sacrificial anode described above can be used. It is formed into a thin plate.

In this second embodiment, as shown in FIG. 3, the sacrificial anode tape 8 is wound around the lower portion of the tube 3. At the time of this winding, it is preferable to use an adhesive containing a conductive substance. In the present embodiment, the sacrificial anode tape 8 can maintain the anticorrosion potential.

According to this method, there is no need for conventional work such as sand blasting or re-spraying, and since it is only necessary to wind the sacrificial anode tape 8, it is possible to cope with the problem at low cost and in a short period of time. In addition, according to the sacrificial anode tape 8, tube breakage due to thermal stress unlike the conventional case does not occur.

Next, with reference to FIG. 4, a third embodiment of the method for corrosion protection alternative to the thermal spray coating of the vaporizer according to the present invention will be described.

FIG. 4 is a perspective view showing a tube portion of a vaporizer that has been subjected to anticorrosion treatment by a third embodiment of the spray coating alternative anticorrosion method for a vaporizer according to the present invention.

In FIG. 4, reference numeral 9 is a sacrificial anode tape, and as the material of the sacrificial anode tape 7 shown in FIG. 2, the material that can be used as the above-mentioned sacrificial anode can be used. It is formed into a thin plate.

In the third embodiment, as shown in FIG. 4, the sacrificial anode tape 9 is attached to the fin 3a of the tube 3. In FIG. 4, the sacrificial anode tape 9 is attached to the entire surface so as to reach the two fins between the tubes adjacent to each other among the plurality of tubes 3, but the sacrificial anode tape 9 may be attached partially. In addition, it is preferable to use an adhesive mixed with a conductive substance at the time of this attachment. In the present embodiment, the sacrificial anode tape 9 can maintain the anticorrosion potential.

According to this method, the conventional work such as sand blasting and re-spraying is unnecessary, and since it is only necessary to attach the sacrificial anode tape 9, it is possible to cope with the problem at low cost and in a short period of time. . In addition, according to the sacrificial anode tape 9, tube cracking due to thermal stress unlike the conventional case does not occur.

Further, according to this method, the function as a sacrificial anode can be achieved even when the panel surface formed by the fins 3a is iced, the restrictions on the heat exchange medium type and the load amount are relaxed, and the applicable range is expanded. There is also the effect.

The vaporizer to which the sacrificial anode tape 9 is attached is not limited to the one in which the sacrificial anode has been consumed, and the sacrificial anode tape 9 is attached to a new vaporizer instead of spraying the sacrificial anode coating. You may do it.

FIG. 5 is a perspective view showing a tube portion of a vaporizer subjected to anticorrosion treatment according to a fourth embodiment of the spray coating alternative anticorrosion method for a vaporizer according to the present invention.

In the fourth embodiment, in addition to the third embodiment shown in FIG. 4, the band 10 is used to fix the sacrificial anode tape 9 for band fixing. By doing so, there is an effect that the sacrificial anode tape 9 can be made difficult to peel off against the falling seawater. Therefore, the band 10 may be provided on the upper portion and the lower portion of the sacrificial anode tape 9 as shown in FIG. 5, but may be provided only on the upper portion.

FIG. 6 is a perspective view showing a tube portion of a vaporizer which has been subjected to an anticorrosion treatment by a fifth embodiment of a spray coating alternative anticorrosion method for a vaporizer according to the present invention.

In the fifth embodiment, in addition to the third embodiment shown in FIG. 4, rivet heads are alternately arranged on the front and back of the fin for fixing the sacrificial anode tape 9. The rivet 11 is used to stop rivets. By doing so, the sacrificial anode tape 9 is less likely to peel off against the pouring seawater, and the seawater can flow down along the fins without being obstructed. After all, for this reason, 1 rivet
0 may be provided all over the sacrificial anode tape 9 as shown in FIG. 6, but may be provided only on the upper part.

FIG. 7 is a plan sectional view for explaining another example of the portion to which the sacrificial anode tape 9 is attached in the third to fifth embodiments of the spray coating alternative anticorrosion method for a vaporizer according to the present invention. .

4 to 6, the sacrificial anode tape 9 is attached to one surface of each of the panels formed by the two fins of the adjacent tubes, but the present invention is not limited thereto. For example, the sacrificial anode tapes 9 may be attached to the surface indicated by the arrow A at the position shown by the arrow A in FIG. When the thermal spray coating provided on the surface of the vaporizer 1 is further consumed and the anticorrosive potential cannot be maintained, the sacrificial anode tape 9 is attached only to the surface indicated by the arrow B at the position indicated by the arrow B in FIG. You may attach it.

[0051]

As described above, according to the present invention, an inexpensive corrosion coating alternative corrosion protection method for a vaporizer which can be performed at a low cost for a short period of time and can perform corrosion protection without fear of damage to the tube or the like due to thermal stress. And a vaporizer can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a vaporizer according to the present invention.

FIG. 2 is a perspective view showing a lower portion of a vaporizer that has been subjected to anticorrosion treatment by the first embodiment of the spray coating alternative anticorrosion method for a vaporizer according to the present invention.

FIG. 3 is a perspective view showing a lower portion of a vaporizer subjected to anticorrosion treatment by a second embodiment of a spray coating alternative anticorrosion method for a vaporizer according to the present invention.

FIG. 4 is a perspective view showing a part of a tube of a vaporizer which has been subjected to anticorrosion treatment by a third embodiment of a spray coating alternative anticorrosion method for a vaporizer according to the present invention.

FIG. 5 is a perspective view showing a part of a tube of a vaporizer that has been subjected to an anticorrosion treatment by a fourth embodiment of a spray coating alternative anticorrosion method for a vaporizer according to the present invention.

FIG. 6 is a perspective view showing a tube portion of a vaporizer subjected to anticorrosion treatment according to a fifth embodiment of the spray coating alternative corrosion protection method for a vaporizer according to the present invention.

FIG. 7 is a plan cross-sectional view illustrating another example of a portion to which a sacrificial anode tape is attached in the third to fifth embodiments of the sprayed coating alternative anticorrosion method for a vaporizer according to the present invention.

[Explanation of symbols]

1 vaporizer 2 bottom header 3 tubes 3a fin 4 Upper header 5 supply ports 6 outlets 7, 8, 9 Sacrificial anode tape 10 bands 11 rivets

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F17C 9/02 F16L 41/02 AF term (reference) 3E073 DC11 3H019 BA43 BD02 3H024 DA05 EA02 EB09 EC08 ED08 4G075 AA53 CA51 DA02 FC09 FC11

Claims (9)

[Claims] 1. A lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube, and a supply port of the upper header. A vaporizer delivered from, in a spray coating alternative anticorrosion method of the vaporizer whose surface is subjected to corrosion protection by a spray coating as a sacrificial anode, when the spray coating is exhausted, at a predetermined position of the vaporizer A corrosion protection alternative to a thermal spray coating for a vaporizer, characterized in that a corrosion protection potential is maintained by applying a thin plate sacrificial anode tape. 2. A lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube, and a supply port of the upper header. A vaporizer delivered from, in a spray coating alternative anticorrosion method of the vaporizer whose surface is subjected to corrosion protection by a spray coating as a sacrificial anode, when the spray coating is exhausted, a thin plate-like in the lower header A method for alternative corrosion protection of a vaporizer spray coating, characterized in that the corrosion protection potential is maintained by winding a sacrificial anode tape. 3. A lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube, and a supply port of the upper header. A vaporizer delivered from a vaporizer, wherein the surface of the vaporizer is corrosion-protected by a spray coating as a sacrificial anode. A method for preventing corrosion by spray coating of a vaporizer, characterized in that the corrosion protection potential is maintained by winding the sacrificial anode tape. 4. A plurality of tubes having a lower header and fins and an upper header, wherein the LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube. A vaporizer delivered from the outlet of the above, in a spray coating alternative anticorrosion method of a vaporizer whose surface is subjected to corrosion protection by a spray coating as a sacrificial anode, when the spray coating is consumed, a thin plate is formed on the fin. A method for preventing corrosion by spray coating on a vaporizer, characterized in that the corrosion protection potential is maintained by applying a sacrificial anode tape. 5. The band stop is performed when the sacrificial anode tape is attached to the fins.
An alternative corrosion protection method for a vaporized coating of a vaporizer according to. 6. The method of claim 4, wherein rivet fixing is performed when the sacrificial anode tape is attached to the fins. 7. A lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube, and a supply port of the upper header. A carburetor provided by the above method, wherein a corrosion protection potential is maintained by winding a thin plate-shaped sacrificial anode tape around the lower header. 8. A lower header, a plurality of tubes, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube, and a supply port of the upper header. A vaporizer which is provided by the above, wherein the sacrificial anode tape in a thin plate shape is wound around the lower portion of the tube to maintain the anticorrosion potential. 9. A plurality of tubes having a lower header and fins, and an upper header, wherein LNG supplied from a supply port of the lower header is heat-exchanged and vaporized when passing through the tube. In the vaporizer which is delivered from the outlet of the above, the vaporizer is characterized in that a corrosion protection potential is maintained by attaching a thin plate-shaped sacrificial anode tape to the fins.