JP2008249200A - Heat transfer pipe and header pipe for open rack type carburetor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transfer pipe for an open rack type carburetor and a header pipe for the open rack type carburetor capable of preventing occurrence of corrosion and damage even near a welding joint portion of the header pipe and the heat transfer pipe, and having high durability, with respect to the heat transfer pipe in the oven rack type carburetor and the header pipe at a liquefied natural gas introduction side. <P>SOLUTION: This heat transfer pipe for the open rack type carburetor has a reinforcement fiber-containing resin coating layer composed of reinforcement fiber and a vinyl ester resin having a glass transition point of 60°C or less, and having a thickness of 50 μm or more, on a part or the whole of an outer surface. This header pipe for the open rack-type carburetor has a reinforcement resin-containing resin coating layer composed of the reinforcement fiber and a resin mainly composed of a vinyl ester resin having a glass transition point of 60°C or less, having a thickness of 50 μm or more on a part or the whole of an outer surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat transfer tube in an open rack type carburetor and a header tube on the liquefied natural gas introduction side, and corrosion damage hardly occurs in the vicinity of the welded joint between the header tube and the heat transfer tube. The present invention relates to a heat transfer tube for an open rack type vaporizer and a header tube excellent in durability against repeated heat cycles at normal temperature at the time of stoppage.

  FIG. 2 is a view showing an outline of an open rack type vaporizer, in which (a) is a front view and (b) is a sectional view. FIG. 3 is a view for explaining a welded joint between the lower header tube and the heat transfer tube.

  An open rack type vaporizer is a heat exchanger that vaporizes liquefied natural gas (LNG) by heat exchange with seawater as a heat source. As shown in FIG. 2, seawater is stored in a trough 7, and the outer surface of a heat transfer panel (heat transfer tube panel) 1 formed by arranging a large number of heat transfer tubes 2 in a panel shape and joining to header tubes 3 and 4 is arranged upward. Flows down from. On the other hand, the liquefied natural gas is sent to the lower header pipe 3 through the lower manifold 5, heated by heat exchange with seawater, vaporized and raised in each heat transfer pipe 2 of the heat transfer panel 1. Then, natural gas is led out from the upper manifold 6 through the upper header pipe 4. As shown in FIG. 3, the lower end portion of the heat transfer tube 2 is welded to the lower header tube 3.

  In the heat transfer tube of this open rack type vaporizer (heat transfer tube for open rack type vaporizer), the vicinity of the welded joint (including the joint) with the header pipe is susceptible to corrosion due to metal structure changes such as compound precipitation due to welding. In many cases, it becomes a state. In addition, the lower header pipe on the liquefied natural gas introduction side and the lower part of the heat transfer panel (lower part of the heat transfer pipe), the seawater of the heating source becomes low temperature (about 0 ° C) by liquefied natural gas (about -160 ° C). Therefore, the amount of dissolved oxygen is large and the environment is severely corrosive. For this reason, the corrosion damage in the vicinity of the welded joint between the lower header pipe and the heat transfer pipe is significant, which dominates the life of the open rack type vaporizer.

  In addition, as mentioned above, the lower header tube on the liquefied natural gas introduction side and the lower part of the heat transfer panel are exposed to extremely low temperatures (about -160 ° C) as the liquefied natural gas is vaporized. The surface of the tube that comes into contact with seawater due to heat conduction from it is very likely to be extremely cold. In addition, when liquefied natural gas is vaporized (during operation), seawater from heat exchange is always applied to the lower header tube and the heat transfer panel (heat transfer tube), so the surface of the lower header tube and the heat transfer panel is a so-called erosion metal. It is inevitable to worry about wear and tear.

  Therefore, an open rack type vaporizer fin tube has been proposed in which a sacrificial anticorrosive metal layer (such as an Al-Zn alloy) is formed on the heat transfer tube surface by thermal spraying or cladding, thereby improving the anticorrosion property. (For example, JP-A-5-16496 (Patent Document 1)).

  However, in the corrosion prevention by the formation of the sacrificial anticorrosive metal layer, the sacrificial anticorrosive metal layer may be consumed depending on the use environment only by applying the sacrificial anticorrosive metal layer by thermal spraying at the lower header tube or the lower part of the heat transfer panel (lower part of the heat transfer tube). In many cases, it is extremely fast and cannot fully perform its function. In addition, when using a material in which a sacrificial anticorrosive metal layer is formed of a clad, it is necessary to remove the sacrificial anticorrosive metal layer at the welded joint between the heat transfer tube and the header pipe. Therefore, a separate anti-corrosion treatment is required.

  Although it is possible to form anti-corrosion coating such as tar epoxy paint, at the lower header and the lower part of the heat transfer tube (especially near the welded joint between the heat transfer tube and the lower header tube) Since there is a problem that the anticorrosion paint freezes and peels due to repeated thermal cycling with normal temperature, there seems to be almost no practical example.

  JP 2004-293811 A (Patent Document 2) proposes an open rack vaporizer heat transfer tube in which an organic coating layer containing petrolatum is formed on the outer surface in order to obtain high corrosion resistance. However, the organic coating layer containing petrolatum alone is insufficient in erosion resistance because of its low hardness. In this case, even if a hard layer such as an epoxy resin, a fluororesin, or an acrylic resin is provided on the organic material coating layer, the layer is also frozen and peeled off by a thermal cycle, which is insufficient for erosion resistance protection. It is.

  Japanese Patent Laid-Open No. 2003-213461 (Patent Document 3) discloses that an uncured liquid vinyl ester resin composition is applied to the surface of a steel structure or a concrete steel structure, and a transparent resin sheet is placed on the coating film. An anticorrosion method for a steel structure or a concrete steel structure has been proposed in which the entire structure is bonded and integrated by covering and overlapping with ultraviolet rays. However, this anticorrosion method is applied in a normal corrosive environment such as extreme temperature, humidity, and salinity range, unlike the corrosive environment in the extremely low temperature range where the heat transfer tube and lower header tube of the open rack type vaporizer are placed. The technology is based on

Japanese Patent Laid-Open No. 5-16496 (2nd page, FIG. 1) Japanese Patent Laying-Open No. 2004-293811 (second page) Japanese Patent Laying-Open No. 2003-213461 (second page, FIG. 2)

  Therefore, the problem of the present invention is that the heat transfer tube in the open rack type vaporizer and the header tube on the liquefied natural gas introduction side are less likely to be corroded near the welded joint between the header tube and the heat transfer tube. An object of the present invention is to provide an excellent heat transfer tube for an open rack type vaporizer and a header tube for an open rack type vaporizer.

  In order to solve the above problems, the present invention takes the following technical means.

  The invention of claim 1 is an open rack type vaporizer transmission in which liquefied natural gas is circulated inside, seawater is supplied to the outer surface, and the seawater and the liquefied natural gas exchange heat to vaporize the liquefied natural gas. The heat tube has a reinforcing fiber-containing resin coating layer having a thickness of 50 μm or more, consisting of reinforcing fibers and a vinyl ester resin having a glass transition temperature of 60 ° C. or less on a part or the whole of the outer surface. It is a heat transfer tube for an open rack type vaporizer.

  The invention according to claim 2 is the open rack type vaporizer heat transfer tube according to claim 1, wherein when the vinyl ester resin forms a resin layer made of the vinyl ester resin, the resin layer has a Vickers at -120 ° C. When the hardness value is a and the Vickers hardness value at room temperature is b, a / b ≧ 1.5 (where b ≧ 10 Hv) is satisfied.

  The invention according to claim 3 is the heat transfer tube for an open rack type vaporizer according to claim 1 or 2, wherein the reinforcing fiber in the reinforcing fiber-containing resin coating layer is 20% by mass with respect to the total mass of the reinforcing fiber-containing resin coating layer. It is characterized by being contained above.

  The invention of claim 4 is the open rack type vaporizer heat transfer tube according to any one of claims 1 to 3, wherein the reinforcing fiber present in the reinforcing fiber-containing resin coating layer has a short side length of 20 μm or more. , Selected from those having a long side length of 50 μm or more and a thin chip shape, and those having a thin mat shape in which single fibers having a diameter of 5 μm or more are dispersed like a nonwoven fabric. It is one or two types.

  The invention of claim 5 is the heat transfer tube for an open rack type vaporizer according to any one of claims 1 to 4, which is below the reinforcing fiber-containing resin coating layer and immediately above the heat transfer tube substrate. Further, it has a thermal spray coating layer of an Al alloy as an intermediate layer.

  The invention of claim 6 is an open rack type vaporizer header pipe which distributes liquefied natural gas to a plurality of heat transfer pipes, and a vinyl ester resin having a reinforcing fiber and a glass transition temperature of 60 ° C. or less on a part or the whole of the outer surface. An open rack type vaporizer header pipe having a reinforcing fiber-containing resin coating layer having a thickness of 50 μm or more.

  The invention according to claim 7 is the open rack type vaporizer header pipe according to claim 6, wherein when the vinyl ester resin forms a resin layer made of the vinyl ester resin, the resin layer has a Vickers at -120 ° C. When the hardness value is a and the Vickers hardness value at room temperature is b, a / b ≧ 1.5 (where b ≧ 10 Hv) is satisfied.

  The invention according to claim 8 is the header tube for an open rack type vaporizer according to claim 6 or 7, wherein the reinforcing fiber is 20% by mass with respect to the total mass of the reinforcing fiber-containing resin coating layer in the reinforcing fiber-containing resin coating layer. It is characterized by being contained above.

  The invention according to claim 9 is the header tube for an open rack type vaporizer according to any one of claims 6 to 8, wherein the reinforcing fiber present in the reinforcing fiber-containing resin coating layer has a short side length of 20 μm or more. 1 type or 2 types selected from a chip having a long side length of 50 μm or more and a thin chip shape, and a glass chip having a diameter of 5 μm or more to form a thin mat shape It is characterized by this.

  The invention of claim 10 is the open rack type vaporizer header pipe according to any one of claims 6 to 9, which is below the reinforcing fiber-containing resin coating layer and immediately above the header pipe base material. Further, it has a thermal spray coating layer of an Al alloy as an intermediate layer.

  A heat transfer tube for an open rack type vaporizer according to the present invention comprises a reinforcing fiber-containing resin coating having a reinforcing fiber and a vinyl ester resin having a glass transition temperature of 60 ° C. or lower, partially or entirely on the outer surface, and having a thickness of 50 μm or more. The reinforcing fiber-containing resin coating layer has appropriate hardness and toughness. Therefore, the reinforcing fiber-containing resin coating layer has little thickness loss due to seawater erosion, and is less likely to crack or peel even in an environment where the cryogenic temperature during operation and the ordinary temperature during operation stop are repeated. Therefore, the heat transfer tube for an open rack type carburetor of the present invention is excellent in durability because corrosion damage hardly occurs in the vicinity of the welded joint with the lower header tube on the liquefied natural gas introduction side.

  The header tube for an open rack type vaporizer according to the present invention comprises a reinforcing fiber-containing resin coating having a reinforcing fiber and a vinyl ester resin having a glass transition temperature of 60 ° C. or lower, partially or entirely on the outer surface, and having a thickness of 50 μm or more. The reinforcing fiber-containing resin coating layer has appropriate hardness and toughness. Therefore, the reinforcing fiber-containing resin coating layer has little thickness loss due to seawater erosion, and is less likely to crack or peel even in an environment where the cryogenic temperature during operation and the ordinary temperature during operation stop are repeated. Therefore, the header tube for an open rack type carburetor of the present invention is excellent in durability because corrosion damage hardly occurs even in the vicinity of the weld joint with the lower end portion of the heat transfer tube.

  Hereinafter, the open rack type vaporizer heat transfer pipe (hereinafter also referred to as ORV heat transfer pipe) and the open rack type vaporizer header pipe (hereinafter also referred to as ORV header pipe) of the present invention will be described in detail.

  First, the structure of the reinforcing fiber-containing resin coating layer will be described.

  The ORV heat transfer tube and the ORV header tube of the present invention are composed of a reinforcing fiber and a vinyl ester resin having a glass transition temperature of 60 ° C. or less on a part or the whole of the outer surface, and a reinforcing fiber having a thickness of 50 μm or more. It has a containing resin coating layer. That is, the reinforcing fiber-containing resin coating layer is composed of a composite material of high-strength reinforcing fibers such as glass fibers and a vinyl ester resin having high toughness as a matrix (matrix) resin. The thickness is less worn by erosion of seawater, and by providing appropriate toughness, cracking and peeling are unlikely to occur even in an environment where the cryogenic temperature during operation and the ordinary temperature during operation stop are repeated.

  FIG. 1 is a cross-sectional view schematically showing the structure of a reinforcing fiber-containing resin coating layer according to the present invention. As shown in FIG. 1, the reinforcing fiber-containing resin coating layer has reinforcing fibers in the lower part of the layer, and has a laminated structure in which reinforcing fibers and a matrix resin (vinyl ester resin) are laminated as a whole. .

  Next, the matrix resin constituting the reinforcing fiber-containing resin coating layer will be described.

  As the matrix resin constituting the reinforcing fiber-containing resin coating layer, a vinyl ester resin is preferable. A vinyl ester resin (referred to as an epoxy acrylate resin) is obtained by esterifying various epoxy compounds using acrylic acid or methacrylic acid and adding a polymerizable monomer to form an addition polymerization type. Vinyl ester resins include bisphenol-based vinyl ester resins made from bisphenol A epoxy and novolak-based vinyl ester resins made from novolac-type epoxy. In the present invention, any of these types of vinyl ester resins can be used, but bisphenol vinyl ester resins (bisphenol A type vinyl ester resins) are preferred. The reason is that bisphenol-based vinyl ester resins exhibit excellent chemical resistance against chemicals such as acid, alkalinity, salts, and chlorine, and are excellent in impact resistance, thermal shock resistance and crack resistance. is there.

  If the glass transition temperature of the bisphenol-based vinyl ester resin is 60 ° C. or lower, it is possible to have not only hardness but also moderate toughness, which makes it possible to achieve the extremely low temperature characteristic of an open rack type vaporizer. In a repetitive environment at room temperature and normal temperature, it is possible to obtain a reinforced fiber-containing resin coating layer that hardly breaks or peels off and has excellent durability.

  The glass transition temperature of the vinyl ester resin is measured using a differential thermal analyzer (for example, DSC220C manufactured by Seiko Instruments Inc.) at a temperature increase rate of 10 ° C./min in the range of −50 ° C. to 300 ° C. The temperature was raised and measured by differential thermal analysis of the sample.

  The reinforcing fiber-containing resin coating layer is required to have a contractibility with respect to a temperature difference between a cryogenic temperature during operation of an open rack type vaporizer and a normal temperature when operation is stopped, and durability against vibration during operation. Therefore, in order for the bisphenol-based vinyl ester resin constituting the reinforcing fiber-containing resin coating layer to have flexibility (shrinkability) with respect to a temperature difference in the resin itself, a resin layer made of the bisphenol-based vinyl ester resin When the value of Vickers hardness at −120 ° C. of the resin layer is a and the value of Vickers hardness at room temperature is b, a / b ≧ 1.5 (where b ≧ 10 Hv) is satisfied. It is good to have a characteristic. When the value of a / b is less than 1.5, the flexibility of the bisphenol-based vinyl ester resin with respect to the temperature difference (thermal cycle between extremely low temperature and normal temperature) is insufficient.

  Next, the reinforcing fibers constituting the reinforcing fiber-containing resin coating layer will be described.

  As the reinforcing fibers constituting the reinforcing fiber-containing resin coating layer, glass fibers, carbon fibers, boron fibers, and the like can be used. They are inexpensive, have good adhesion to the matrix resin, have good moldability, and various types. Glass fiber is desirable because the shape is obtained.

  About the shape of the reinforcing fiber existing in the reinforcing fiber-containing resin coating layer, in order to prevent the entry of corrosion factors (seawater) from the outside, there is a defect portion of the reinforcing fiber in the thickness direction in the reinforcing fiber-containing resin coating layer. It is better not to exist. Therefore, the shape of the reinforcing fiber is preferably a chip shape (scale shape) or a mat shape rather than a spherical shape or a rod shape.

  In the case of a chip-shaped reinforcing fiber, it is preferable that the chip has a thin chip shape with a short side length of 20 μm or more and a long side length of 50 μm or more. The size of the chip-shaped reinforcing fibers is more preferably a size having a short side length of 30 μm or more and a long side length of 75 μm or more, and particularly preferably a size having a short side length of 50 μm or more and a long side length of 100 μm or more. The upper limit of the size of the chip-shaped reinforcing fibers is about 1000 μm short side × 2000 μm long side length. The orientation of the chip-shaped reinforcing fibers is preferably random. The presence of chip-shaped reinforcing fibers in the random direction further exhibits the effect of preventing the entry of corrosion factors (seawater) from the outside.

In the case of mat-shaped reinforcing fibers, monofilaments (glass monofilaments) with a diameter of 5 μm or more are uniformly dispersed in a random direction like a non-woven fabric and formed into a thin mat shape with a binder (binder) Is good. The reinforcing fiber may be a combination of a mat-shaped reinforcing fiber and a chip-shaped reinforcing fiber. In addition, the thickness of these reinforcing fibers is 1-20 micrometers from the ease of acquisition.

  Thus, the presence of reinforcing fibers in the reinforcing fiber-containing resin coating layer makes the reinforcing fiber-containing organic coating layer excellent in impact resistance, vibration resistance, fatigue resistance, heat cycle resistance, and erosion resistance. High crack resistance and peeling resistance in the use environment of open rack type vaporizer.

  Here, the amount of the reinforcing fiber to be contained in the reinforcing fiber-containing resin coating layer will be described. The reinforcing fiber is present in the lower part of the reinforcing fiber-containing resin coating layer having a laminated structure as described above, such as seawater. The corrosion factor is the lower layer of the reinforced fiber-containing resin coating layer and immediately above the heat transfer tube base material or header tube base material (Al alloy spray coating layer), or the heat transfer tube base material (Al Alloy) or a header tube base material (Al alloy). For this reason, if the amount of reinforcing fibers contained in the reinforcing fiber-containing resin coating layer is insufficient, the effect cannot be sufficiently exhibited, and the reinforcing fiber-containing resin coating layer itself is not sufficiently strengthened.

  Therefore, the reinforcing fiber-containing resin coating layer may contain reinforcing fibers in an amount of 20% by mass or more, more preferably 30% by mass or more based on the total mass of the reinforcing fiber-containing resin coating layer. The upper limit of the reinforcing fiber content is 70% by mass, more preferably 60% by mass, from the viewpoint of securing the toughness of the resin (bisphenol-based vinyl ester resin) constituting the reinforcing fiber-containing resin coating layer.

  In addition, the reinforcing fiber content of the reinforcing fiber-containing resin coating layer is obtained by preparing a test piece in the same manner as in the case of forming a heat transfer tube or a header tube in an actual open rack type vaporizer (brush coating). It was calculated | required from ratio of the dry weight of the resin coating layer made, and the weight of a reinforced fiber, this was measured 5 times and calculated | required as the average value. Further, when the measurement is made after forming the reinforcing fiber-containing resin coating layer, the reinforcing fiber-containing resin coating layer is sampled from a test piece, and is thermally decomposed with a differential type suggestion thermobalance, and the collected reinforcing fibers are collected. It can be determined from the ratio of the weight of the containing resin coating layer and the remaining reinforcing fibers. Further, the reinforcing fiber-containing resin coating layer collected from the test piece is dissolved in a solvent such as chloroform, ether, benzene, and the ratio is determined from the ratio of the weight of the collected reinforcing fiber-containing resin coating layer and the weight of the remaining reinforcing fibers. be able to.

  Next, the thickness of the reinforcing fiber-containing resin coating layer will be described.

  The reinforcing fiber-containing resin coating layer has excellent properties such as impact resistance and erosion resistance, and serves as a barrier to prevent the entry of corrosive factors such as seawater. The thickness is preferably 50 μm or more, more preferably 100 μm or more. On the other hand, in the open rack type vaporizer for liquefied natural gas, the temperature difference between the upper and lower parts of the heat transfer panel (heat transfer tube + header tube) (extremely low temperature on the liquefied gas inlet side and normal temperature on the outlet side) is suspended. As a result, the heat transfer panel is deformed. In addition, the heat transfer panel vibrates slightly during operation. For this reason, when the thickness of the reinforcing fiber-containing resin coating layer is too thick, such deformation cannot be followed, and heat exchange with seawater decreases, which is not preferable. Therefore, the upper limit of the thickness of the reinforcing fiber-containing resin coating layer is 10 mm or less, more preferably 5 mm or less, and particularly preferably 3 mm or less.

  For the measurement of the thickness of the reinforcing fiber-containing resin coating layer, the test piece is coated with the reinforcing fiber-containing resin in the same manner as when forming (brushing) the heat transfer tube or header tube in an actual open rack type vaporizer. A layer was formed, and the tube (test piece) on which the coating layer was formed was cut perpendicularly to the tube axis direction to cut out a thickness measuring member. Three of these were mirror-polished and each was observed with an optical microscope at a magnification of 50 times, and the minimum value of the obtained thickness measurements was the thickness of the reinforcing fiber-containing resin coating layer. Adopted as.

  Next, the intermediate layer will be described.

  In the ORV heat transfer tube and the ORV header tube of the present invention, an intermediate layer is provided under the reinforcing fiber-containing resin coating layer and immediately above the base substrate (heat transfer tube substrate, header tube substrate). An Al alloy spray coating layer may be provided. By providing an Al alloy sprayed coating layer as an intermediate layer, the reinforcing fiber-containing resin coating layer penetrates into the pores formed on the surface of the Al alloy sprayed coating layer, and exhibits an anchor effect to form an Al alloy sprayed coating layer. Adhesion is improved. In the unlikely event that the reinforcing fiber-containing resin coating layer is missing, the Al alloy sprayed coating layer, which has a lower potential than the Al of the base substrate (heat transfer tube substrate, header tube substrate), elutes, There is also an effect that damage to the base substrate can be prevented.

  Hereinafter, a test for confirming the effect of the present invention was performed.

  First, a test for determining optimum requirements as a resin (matrix resin) constituting the reinforcing fiber-containing resin coating layer according to the present invention was performed.

  In order to form resin layers having different hardnesses, four types of bisphenol A type vinyl ester resins having different molecular lengths were synthesized (resin 1 to resin 4). In a reaction vessel having a capacity of 2 liters equipped with a stirrer, reflux condenser, gas introduction tube and thermometer, 205 g of bisphenol A type epoxy resin (epoxy equivalent 184), 140 g of methacrylic acid, 0.3 g of hydroquinone, and triethylbenzylammonium chloride 1 .1 g was charged. The reaction system was placed in a nitrogen atmosphere, and these raw materials were reacted at 140 ° C. for 4 hours with stirring. To this, 220 g of styrene was added and mixed with stirring to obtain a liquid bisphenol A type vinyl ester resin (hereinafter referred to as “resin 1”).

  Further, in a reaction vessel having a capacity of 2 liters equipped with a stirrer, a reflux condenser, a gas introduction tube and a thermometer, 540 g of bisphenol A type epoxy resin (epoxy equivalent 450), 170 g of methacrylic acid, 0.3 g of hydroquinone, and triethylbenzylammonium 1.1 g of chloride was charged. The reaction system was placed in a nitrogen atmosphere, and these raw materials were reacted at 140 ° C. for 4 hours with stirring. To this, 330 g of styrene was added and mixed with stirring to obtain a liquid bisphenol A type vinyl ester resin (hereinafter referred to as “resin 2”).

  Further, in a reaction vessel having a capacity of 2 liters equipped with a stirrer, a reflux condenser, a gas introduction tube and a thermometer, 970 g of bisphenol A type epoxy resin (epoxy equivalent 880), 220 g of methacrylic acid, 0.3 g of hydroquinone, and triethylbenzylammonium 1.1 g of chloride was charged. The reaction system was placed in a nitrogen atmosphere, and these raw materials were reacted at 140 ° C. for 4 hours with stirring. To this was added 420 g of styrene and mixed with stirring to obtain a liquid bisphenol A type vinyl ester resin (hereinafter referred to as “resin 3”).

  In addition, 2900 g of bisphenol A type epoxy resin (epoxy equivalent 2400), 140 g of methacrylic acid, 0.3 g of hydroquinone, and triethylbenzyl were added to a reaction vessel having a capacity of 2 liters equipped with a stirrer, reflux condenser, gas inlet tube and thermometer. 1.1 g of ammonium chloride was charged. The reaction system was placed in a nitrogen atmosphere, and these raw materials were reacted at 140 ° C. for 4 hours with stirring. To this, 320 g of styrene was added and mixed with stirring to obtain a liquid bisphenol A type vinyl ester resin (hereinafter referred to as “resin 4”).

  In addition, as a commercially available bisphenol A type vinyl ester resin (liquid), Nippon Iupica Neopole 8620 (hereinafter referred to as “resin 5”) and Japan Composite Prominate (hereinafter referred to as “resin 6”) were prepared.

  The glass transition temperature was measured for each of the resins 1 to 6. The results are shown in Table 1.

  And about each of said resin 1-resin 6, while forming the resin layer and measuring the Vickers hardness in -120 degreeC of this resin layer and the Vickers hardness in room temperature, the crack of this resin layer and peeling The presence or absence was observed.

  That is, the surface of the base material made of aluminum alloy A5083 was roughened by shot blasting using # 16 to # 20 alumina abrasive grains so that the arithmetic average roughness Ra satisfies the range of 20 to 40 μm. This roughening is for the purpose of improving the adhesion between the aluminum alloy substrate and the resin layer to be formed. Next, a metal primer resin (manufactured by Showa Polymer: Lipoxy RT-833DA) was brush-coated on the roughened aluminum alloy base substrate. This metal primer resin is intended to enhance the adhesion of the resin layer to be formed to the aluminum alloy base substrate. Next, the resin 1 and Permec N / Co-naphthenic acid (Co: 6%), which is a room temperature curing agent, are mixed at a ratio of 1 part / 0.5 part so as to have a predetermined thickness. Brushing was performed several times. Thereafter, a surface protective film was formed thereon using a surface protective resin (manufactured by Showa Polymer: Lipoxy R-802), and then sufficiently dried to obtain a resin layer made of resin 1.

  Then, it is immersed in liquid nitrogen for 10 minutes, the aluminum base substrate and the resin layer made of resin 1 formed thereon are sufficiently cooled and taken out, and the Vickers hardness at −120 ° C. is measured. (Measured value: a). Moreover, the Vickers hardness at room temperature was measured (measurement value: b). Further, the presence or absence of cracking or peeling of the resin layer made of the resin 1 was examined. Similarly, a resin layer is formed for each of the resins 2 to 6, and the Vickers hardness (measured value: a) at −120 ° C. of the resin layer and the Vickers hardness (measured value: b) at room temperature. ) And the presence or absence of cracking and peeling of the resin layer. The test results are shown in Table 1.

  As is apparent from Table 1, test no. The resin layers 1 to 3 satisfy the requirements specified in the present invention for the glass transition temperature, the hardness a / b ratio, and the thickness, and cracks and peeling after immersion in liquid nitrogen have occurred. There wasn't. Similarly, test No. 1 using resin 1 was used. Although the resin layer in No. 4 satisfies the requirements specified in the present invention for both the glass transition temperature and the hardness a / b ratio, the thickness of the resin layer is insufficient. Some cracks were observed.

  On the other hand, Test No. As for the resin layer in 5-7, the glass transition temperature and hardness a / b ratio are removed from the requirements prescribed | regulated by this invention, the softness | flexibility with respect to a temperature difference is inadequate, and the crack was observed. Test No. 8 and no. The resin layer of No. 9 has a hardness a / b ratio that is not within the requirements defined in the present invention, the flexibility is insufficient, and cracks were observed. From this test result, it was confirmed that the resin 1 is suitable as a resin constituting the reinforcing fiber-containing resin coating layer according to the present invention.

  Next, a cryogenic combined test described below was carried out by imitating an actual machine exposure test.

  The surface of the base material made of aluminum alloy A5083 was roughened by shot blasting using # 16 to # 20 alumina abrasive grains so that the arithmetic average roughness Ra satisfies the range of 20 to 40 μm. On the roughened aluminum alloy substrate, a sprayed coating layer made of Al-2% Zn (Al alloy) and having a thickness of 300 μm was formed as an intermediate layer by thermal spraying. On this sprayed coating layer, a metal primer resin (manufactured by Showa Polymer: Lipoxy RT-833DA) was brush-coated.

  Next, a primer resin for metal (manufactured by Showa Polymer: Lipoxy RT-833DA) was brushed on this sprayed coating layer, and then a reinforcing fiber-containing resin coating layer having a thickness of 500 μm was formed by brush coating.

  When forming this reinforcing fiber-containing resin coating layer, a chip-shaped glass fiber (thickness 3 to 20 μm × short side length 50 to 100 μm × long side length 100 to 200 μm) made of glass fiber is used as the reinforcing fiber (Test Example 3). , Test Example 6 and Test Example 7), a mixture of the resin 1 with these chip-shaped glass fibers, and Parmec N / naphthenic acid Co (Co: 6%) as a normal temperature curing agent at 1 part / 0.0. The mixture mixed at a ratio of 5 parts was brush-coated on the sprayed coating layer having the metal primer resin brushed on its surface, thereby forming a reinforcing fiber-containing resin coating layer. Then, a surface protective film was formed on the reinforcing fiber-containing resin coating layer using a surface protective resin (manufactured by Showa Polymer: Lipoxy R-802) and then sufficiently dried.

  Further, when spherical glass fiber is used as the reinforcing fiber (Test Example 4) and when rod-shaped glass fiber is used (Test Example 5), the reinforcement is performed in the same manner as in the case of the above-described chip-shaped glass fiber. A fiber-containing resin coating layer was formed.

  Further, when a mat-shaped glass fiber (thickness: 100 to 300 μm, glass single fiber diameter: 10 μm) made of glass fiber is used as the reinforcing fiber (Test Example 2), the metal primer resin is brushed on the surface. After laying the mat-shaped glass fiber on the sprayed coating layer, the resin 1 and permec N / Naphthenic acid Co (Co: 6%) as a normal temperature curing agent are mixed at a ratio of 1 part / 0.5 part. The reinforced fiber-containing resin coating layer was formed by brushing the resulting product.

  Further, when the mat-shaped glass fiber and the chip-shaped glass fiber are used in combination as reinforcing fibers (Test Example 1), the mat-shaped glass is formed on the sprayed coating layer having the metal primer resin brushed on the surface. After laying the fiber, the resin 1 mixed with the chip-shaped glass fiber and the room temperature curing agent Permec N / Naphthenic acid Co (Co: 6%) were mixed at a ratio of 1 part / 0.5 part. The reinforced fiber-containing resin coating layer was formed by brushing the resulting product.

  Further, as Comparative Example 1, a resin layer (resin coating layer) having a thickness of 500 μm, which is made of the resin 1 and does not contain reinforcing fibers, without providing the spray coating layer on the base substrate made of aluminum alloy A5083. A formed test piece was prepared. Furthermore, as Comparative Example 2, a test piece formed by forming only the sprayed coating layer on the base substrate was prepared.

  For each of the test pieces of Test Examples 1 to 7 and Comparative Examples 1 and 2 produced in this manner, the electrode was repeated at 35 ° C., 5% saline spray environment (23 hours) -liquid nitrogen immersion (1 hour) as one cycle. The low-temperature composite corrosion test was performed for 60 cycles, and the durability of the reinforcing fiber-containing resin coating layer was investigated. In addition, the visual observation of the reinforcing fiber-containing resin coating layer for detecting cracking and peeling was performed after the number of cycles of 15, 30, and 60, respectively. The test results are shown in Table 2.

  All of Test Examples 1 to 7 were superior in durability in an environment where extremely low temperature and normal temperature (corrosive environment) were repeated as compared with Comparative Example 2 having no reinforcing fiber-containing resin coating layer. It was.

  In particular, those in Test Examples 1 to 3 are those in which the reinforcing fiber-containing resin coating layer has a content of 20% by mass or more and mat-shaped or chip-shaped reinforcing fibers and a vinyl ester resin having a glass transition temperature of 60 ° C. or lower. It is formed and has an intermediate layer (Al-2% Zn sprayed coating layer). Even after the cryogenic combined corrosion test with 60 cycles, the reinforcing fiber-containing resin coating layer is cracked. No peeling occurred, and the durability was excellent in an environment where extremely low temperature and normal temperature (corrosive environment) were repeated.

  Further, in Test Example 4 and Test Example 5, since the shape of the reinforcing fiber was not the shape recommended in the present invention (mat shape or chip shape), no cracking or peeling was observed after 30 cycles. After 60 cycles, cracks were observed in a part of the reinforcing fiber-containing resin coating layer. Since the reinforcing fiber content in Test Example 6 was not sufficient, cracking and peeling were not observed after 15 cycles, but cracking was not observed in the reinforcing fiber-containing resin coating layer after 30 cycles. Observed. Moreover, since the reinforcing fiber content of Test Example 7 was not sufficient, and it did not have an intermediate layer, cracks and peeling were not observed after 15 cycles. After 30 times, cracks were observed in the reinforcing fiber-containing resin coating layer.

  Since the thing of the comparative example 1 is a resin coating layer which does not contain a reinforced fiber, and since it does not have an intermediate | middle layer, although the crack and peeling were not observed after the cycle number 15 times, the cycle number 30 times Later, cracking and peeling were observed in the reinforcing fiber-containing resin coating layer.

  In the actual machine of the open rack type vaporizer, as shown in FIG. 4, in the heat transfer tube, for example, a reinforcing fiber is contained in a portion (including a welded portion) extending about 100 mm above the welded portion with the lower header tube. A resin coating layer is formed. Further, in the lower header pipe, a reinforcing fiber-containing resin coating layer is formed at a site as shown in FIG.

It is sectional drawing which shows typically the structure of the reinforcing fiber containing resin coating layer which concerns on this invention. It is a figure which shows the outline | summary of an open rack type vaporizer, Comprising: The (a) is a front view, The (b) is sectional drawing. It is a figure for demonstrating the welding junction part of a lower header pipe | tube and a heat exchanger tube. It is a figure for demonstrating the site | part which forms the reinforcing fiber containing resin coating layer to a heat exchanger tube and a lower header pipe | tube in an open rack type vaporizer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat transfer panel 2 ... Heat transfer pipe 3 ... Lower header pipe 4 ... Upper header pipe 5 ... Lower manifold 6 ... Upper manifold 7 ... Trough

Claims (10)

  In an open rack type vaporizer heat transfer tube in which liquefied natural gas is circulated and seawater is supplied to the outer surface, and the seawater and the liquefied natural gas exchange heat to vaporize the liquefied natural gas. For an open rack type vaporizer characterized in that it has a reinforcing fiber-containing resin coating layer having a thickness of 50 μm or more, consisting of reinforcing fibers and a vinyl ester resin having a glass transition temperature of 60 ° C. or less on the entire surface or the entire surface. Heat transfer tube.   When the vinyl ester resin forms a resin layer made of the vinyl ester resin, when the value of Vickers hardness at −120 ° C. of the resin layer is a and the value of Vickers hardness at room temperature is b, a / 2. The open rack type vaporizer heat transfer tube according to claim 1, wherein b ≧ 1.5 (where b ≧ 10 Hv) is satisfied.   3. The open rack type vaporizer transmission according to claim 1, wherein the reinforcing fiber-containing resin coating layer contains 20% by mass or more of the reinforcing fiber with respect to the total mass of the reinforcing fiber-containing resin coating layer. Heat pipe.   The reinforcing fibers present in the reinforcing fiber-containing resin coating layer have a short side length of 20 μm or more, a long side length of 50 μm or more and a thin chip shape, and a single fiber having a diameter of 5 μm or more is a nonwoven fabric. The open rack type vaporization according to any one of claims 1 to 3, wherein the vaporization is one type or two types selected from those having a mat shape dispersed into a thin mat shape. Heat transfer tube for dexterity.   5. The thermal spray coating layer of an Al alloy is provided as an intermediate layer on the lower side of the reinforcing fiber-containing resin coating layer and immediately above the heat transfer tube base material. The heat transfer tube for an open rack type vaporizer described in the paragraph.   In an open rack type vaporizer header pipe that distributes liquefied natural gas to a plurality of heat transfer tubes, a part or the whole of the outer surface is composed of reinforcing fibers and a vinyl ester resin having a glass transition temperature of 60 ° C. or less, and the thickness is A header tube for an open rack type vaporizer characterized by having a reinforcing fiber-containing resin coating layer of 50 μm or more.   When the vinyl ester resin forms a resin layer made of the vinyl ester resin, when the value of Vickers hardness at −120 ° C. of the resin layer is a and the value of Vickers hardness at room temperature is b, a / 7. The open rack type vaporizer header pipe according to claim 6, wherein b ≧ 1.5 (where b ≧ 10 Hv) is satisfied.   8. The open rack type vaporizer header according to claim 6, wherein the reinforcing fiber-containing resin coating layer contains 20% by mass or more of the reinforcing fiber with respect to the total mass of the reinforcing fiber-containing resin coating layer. tube.   The reinforcing fibers present in the reinforcing fiber-containing resin coating layer have a short side length of 20 μm or more, a long side length of 50 μm or more and a thin chip shape, and a glass fiber having a diameter of 5 μm or more is thin. The open rack type vaporizer header pipe according to any one of claims 6 to 8, wherein the header pipe is one or two selected from those having a mat shape formed into a mat shape.   10. A thermal spray coating layer of an Al alloy as an intermediate layer below the reinforcing fiber-containing resin coating layer and immediately above the header tube base material. The open rack type vaporizer header tube described in the paragraph.

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