JP2018040531A - Heat exchanger - Google Patents

Abstract

A heat exchanger capable of suitably preventing freezing of a heat medium with a simple configuration is provided. A heat exchanger (1) includes a heating line (2) for circulating a fluid to be heated (L) and a shell (3) surrounding the heating line (2), and a heating medium (A) is supplied into the shell (3) to be heated. A rectifying plate 8 that is configured to exchange heat with the fluid L and has a gradient toward the direction of guiding the heat medium A when viewed from the upstream side of the heat medium A at a position where the flow of the heat medium A is bent in the shell 3. Arrange. The heating line 2 is configured to extract the fluid L to be heated introduced from below, the supply port 4 (lower supply port 4 a) is provided at the lower part of the shell 3, and the rectifying plate 8 is connected to the supply port 4 ( It arrange | positions so that an upward slope may be made seeing from the lower supply port 4a). [Selection] Figure 1

Description

  The present invention relates to a heat exchanger for heating a fluid such as liquefied natural gas.

  Generally, when liquefied natural gas (LNG) is used as a fuel, it is necessary to heat and vaporize LNG stored at a low temperature. At this time, for heating LNG, a fluid such as air or water is used as a heat source. Various types of heat exchangers are used, such as an open rack type heat exchanger to be used and an intermediate medium type heat exchanger that transfers heat from another heat source to the LNG by circulation of the heat medium.

  Among these, in the intermediate medium type heat exchanger, it is necessary to prevent freezing of the heat medium as much as possible in order to exchange heat between the cryogenic LNG and the heat medium. This is because the heat exchange efficiency decreases when the heat medium freezes and the circulation channel is blocked. Therefore, as the heat medium, fluids that are difficult to freeze are often used, such as LPG such as propane and butane, or an antifreeze liquid mainly composed of ethylene glycol or propylene glycol.

  As a technical document regarding a heat exchanger that employs an antifreeze liquid as a heat medium, for example, there is Patent Document 1 below.

  Antifreezes using ethylene glycol or propylene glycol have the advantage of being less ignitable and higher in safety than propane and butane, but also have the problem of high freezing point and easy freezing. For this reason, in the heat exchanger (LNG vaporizer) described in Patent Document 1, the body portion includes a lower first heat exchange portion, an upper second heat exchange portion, and an upper third heat exchange portion. The first heat exchanging part that is located near the inlet of the LNG in the vertical heat transfer tube and is likely to become low temperature by dividing into three heat exchanging parts and controlling the flow rate of the antifreezing liquid supplied to each by the antifreeze liquid flow control device The temperature of the antifreeze liquid is maintained sufficiently higher than the freezing temperature to prevent the antifreeze liquid from freezing.

JP 2007-247797 A

  However, in the heat exchanger as described in Patent Document 1, it is necessary to form an antifreeze liquid flow path for each of the three heat exchange sections, and each flow path is not equipped with a valve or the like for flow rate control. In addition, the entire apparatus is complicated and the construction cost increases, and there is a problem that frequent and complicated maintenance work is required.

  In addition, although the heat exchanger for vaporizing LNG was demonstrated here as an example, the same problem may exist widely about the heat exchanger for heating not only LNG but general fluid. For example, the situation is the same in a heat exchanger or the like used for vaporizing liquefied ethylene in a chemical plant or the like.

  In view of such circumstances, the present invention intends to provide a heat exchanger that can suitably prevent freezing of a heat medium with a simple configuration.

  The present invention includes a heating line for circulating a fluid to be heated therein, and a shell surrounding the heating line, and is configured to supply a heat medium into the shell to exchange heat with the fluid to be heated. The heat exchanger is provided with a baffle plate that is inclined toward the direction in which the heat medium is guided as viewed from the upstream side of the heat medium at a position where the flow of the heat medium is bent.

  In the heat exchanger of the present invention, it is preferable that a heat medium supply port is provided at a position on the inlet side of the heating line in the shell, and the rectifying plate is disposed at a position facing the supply port.

  In the heat exchanger according to the present invention, the heating line is configured to draw upward the fluid to be heated introduced from below, the supply port is provided at a lower portion of the shell, and the rectifying plate is a bottom portion of the shell. It is preferable that they are arranged so as to form an upward slope as viewed from the supply port.

  In the heat exchanger according to the present invention, it is preferable that the rectifying plate is configured to have a surface that smoothly curves in a direction in which the heat medium is guided from the upstream side of the heat medium.

  In the heat exchanger of the present invention, the heating line is configured as a heating channel group in which a plurality of channels are bundled, and a seal plate that blocks the flow of the heat medium is provided between the inner wall of the shell and the heating line. It is preferable that at least a part of the seal plate is formed as a gradient portion that forms a gradient in a direction in which the rectifying plate guides the heat medium when viewed from the upstream side of the heat medium.

  According to the heat exchanger of the present invention, it is possible to achieve an excellent effect that the freezing of the heat medium can be suitably prevented with a simple configuration.

It is the schematic which shows the whole structure of the heat exchanger by implementation of this invention. It is sectional drawing which shows arrangement | positioning of each part in the shell in the heat exchanger of a present Example, and is a II-II arrow equivalent view of FIG. It is a perspective view which shows arrangement | positioning of each part in the shell in the heat exchanger of a present Example. It is a conceptual diagram explaining the behavior of the heat medium in the heat exchanger of a present Example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 show an example of a heat exchanger according to an embodiment of the present invention. FIG. 1 shows the overall configuration of the heat exchanger of the present embodiment. The heat exchanger 1 covers the periphery of a heating line 2 through which a heated fluid L such as LNG circulates with a shell 3. This is a type called a shell and tube type in which a heat medium A such as an antifreeze is supplied and heat is exchanged with the heated fluid L.

  The heating line 2 is formed as a heating flow path group (tube bundle) in which a plurality of metal tubes 2a as flow paths extending in the vertical direction are bundled, for example, and the center of the vertically long shell 3 is formed in the center. It arrange | positions so that a part may be penetrated up and down. The heating line 2 has an inlet 2b at the lower part and an outlet 2c at the upper part, and the fluid L to be heated is introduced into the heating line 2 from below the heat exchanger 1 and extracted upward. In addition, the dashed-dotted line in FIG.2 and FIG.3 has shown the area | region where the tube 2a is arrange | positioned as a bundle.

  The heat medium A has a space around the heating line 2 in the shell 3 as a flow path. In the case of this embodiment, the heat medium A is supplied from the supply ports 4 opened at the upper and lower portions of the side surface of the shell 3. It is discharged from the discharge port 5 opened in the middle part. Thus, the heat medium A flowing through the shell 3 exchanges heat while being in contact with the heated fluid L flowing through the heating line 2 via the tube 2a. In the shell 3, a plurality of baffle plates 6 are installed in order to secure as many opportunities as possible for the heat medium A to exchange heat with the heated fluid L flowing in the heating line 2. Is meandering in the shell 3 while bypassing the baffle plate 6.

  The lower supply port 4a is provided at the lower part of the shell 3 as shown in FIG. 1, and the heat medium A is supplied into the shell 3 along the horizontal direction in a direction perpendicular to the heating line 2 from here. The Of the baffle plates 6, the lowermost baffle plate 6 a is divided so as to cross the inside of the shell 3 in a horizontal direction above the lower supply port 4 a as shown in FIGS. 1 and 2. The baffle plate 6a is not closed near the inner wall of the shell 3 opposite to the lower supply port 4a, and has an opening between the inner wall and the baffle plate 6a. Further, the baffle plate 6b located on one level of the baffle plate 6a forms a surface along the horizontal direction above the baffle plate 6a as shown in FIG. An opening exists between the inner wall of the shell 3. Further, the baffle plate 6c located on one step of the baffle plate 6b is disposed so as to cross over the baffle plate 6b, but an opening is formed between the lower supply port 4a and the inner wall of the shell 3 on the opposite side. Existing.

  Therefore, the heat medium A introduced into the shell 3 from the lower supply port 4a first flows in the vicinity of the bottom surface of the shell 3 along the horizontal direction, and bypasses the baffle plate 6a near the inner wall on the side opposite to the lower supply port 4a. However, it flows upward. Furthermore, after flowing along the horizontal direction between the baffle plate 6a and the baffle plate 6b toward the lower supply port 4a side, it flows upward while bypassing the baffle plate 6b.

  In this manner, the baffle plates 6 are alternately arranged in the shell 3 with respect to the flow path of the heat medium A, whereby the heat medium A introduced from the lower supply port 4a is meandered in the shell 3 and the discharge port 5 It has come to lead to.

  Similarly, the heat medium A supplied from the upper supply port 4 b is guided downward while meandering in the shell 3 by the baffle plates 6 arranged alternately in the shell 3, and discharged from the discharge port 5. It has become so.

  Here, the fact that one of the two supply ports 4 (the lower supply port 4a) is provided at the lower portion of the shell 3 is effective in improving heat exchange efficiency and preventing freezing of the heat medium A. . That is, as described above, the low-temperature heated fluid L is introduced into the heating line 2 from the lower inlet 2b of the shell 3 and moves toward the upper outlet 2c while exchanging heat. The heat medium A flowing through the heat medium A comes into contact with the heated fluid L having a lower temperature. For this reason, in the case of the heat exchanger 1 of the present embodiment, the heat medium A is supplied from the lower part of the shell 3 on the inlet 2b side with respect to the heating line 2 and is introduced into the heating line 2 and the temperature is low soon. By bringing the heated medium L into contact with the heated fluid L immediately after being supplied to the shell 3, the heat medium A is brought into contact with the heated fluid L efficiently, and at the same time, freezing of the heated medium A is prevented as much as possible.

  In this embodiment, the heat medium A is supplied from the upper supply port 4b in addition to the lower supply port 4a. This is a configuration for further heating the heated fluid L vaporized while passing through the heating line 2. That is, when the fluid L to be heated is, for example, LNG stored at a very low temperature, the temperature may still not reach an appropriate temperature even if it is vaporized. By supplying, we are trying to warm up to the appropriate temperature.

  In addition to forming the flow path of the heat medium A as described above, the baffle plate 6 also serves to restrain the tubes 2a constituting the heating line 2 and support the shell 3 at the same time. Each tube 2a is thin and extends vertically in the shell 3 so that deformation such as bending is likely to occur unless supported by any means. Therefore, the baffle plate 6 traversing the inside of the shell 3 is passed through each tube 2a as shown in FIG. 2, and the baffle plate 6 is fixed to the shell 3 to support the tube 2a constituting the heating line 2. Like to do. In addition, the baffle plate 6 also has an effect that the distance between the tubes 2a is properly maintained. That is, when the heating line 2 is assembled to the shell 3, for example, first, holes are opened in the plurality of baffle plates 6 at a predetermined interval, and a tube bundle is formed by fixing the holes through the tubes 2a. Then, the tube bundle is accommodated together with the baffle plate 6 in the shell 3, and the baffle plate 6 is fixed to the inner wall of the shell 3 by welding or the like. If it does in this way, the space | interval of the tubes 2a can be prescribed | regulated easily and reliably by the said hole opened to the baffle plate 6, and the flow-path area between tubes 2a is made equal, and homogenization of a heat exchange efficiency is achieved. be able to.

  Further, a plurality of seal plates 7 as shown in FIGS. 1 to 3 are provided in the shell 3, and the flow of the heat medium A is partially blocked by the seal plates 7, so that the heat medium in the shell 3. A is prevented from flowing off the heating line 2. In FIG. 3, illustration of the baffle plate 6 and the like is omitted for convenience of explaining the shape of the seal plate 7 and the positional relationship with the heating line 2.

  The tube bundle constituting the heating line 2 is arranged at the center portion of the shell 3 as described above, and is suitable between the low-temperature heated fluid L flowing through the heating line 2 and the space outside the shell 3. A layer of the heat medium A having a sufficient thickness is interposed. If the seal plate 7 as in the present embodiment is not disposed here, if the heat medium A is caused to flow through the heating line 2, the flow of the heat medium A deviates from the heating line 2 and the heating line 2. It tries to flow in the space outside.

  That is, the heating line 2 is configured as a tube bundle composed of a large number of tubes 2a as described above, and the heat medium A flows between the tubes 2a that are spaced apart from each other by a predetermined distance. Heat exchange is performed with the heated fluid L flowing in 2a. And the clearance gap between these tubes 2a is narrower than the space between the heating line 2 which is a tube bundle, and the inner wall of the shell 3, and flow path resistance is large. For this reason, if there is no seal plate 7, most of the heat medium A will pass between the inner walls of the shell 3 outside the heating line 2 without flowing between the tubes 2a. In order to prevent this, the seal plate 7 is a plate-like member disposed between the inner wall of the shell 3 and the heating line 2.

  As shown in FIGS. 2 and 3, the seal plate 7 extends from the inner wall of the shell 3 in a vertical direction toward the heating line 2, and its lower end is connected to the lower supply port 4a. It bends toward the bottom to form a later-described gradient portion 7a. The surface formed by each seal plate 7 is orthogonal to the flow of the heat medium A introduced from the supply port 4 or the flow of the heat medium A flowing in the horizontal direction between the baffle plates 6 in plan view.

  Each seal plate 7 is integrally welded to the inner wall of the shell 3 on one side extending in the vertical direction, and the other side is positioned in the vicinity of the heating line 2. If the seal plate 7 is arranged in this way, when the heat medium A flows between the baffle plates 6 along the horizontal direction (see FIG. 1), the seal plate 7 blocks the heat plate 2 even if it tries to flow outside the heating line 2. Therefore, it will forcibly flow into the gap between the tubes 2a constituting the heating line 2.

  Here, it is preferable that the other side of the seal plate 7 is disposed with respect to the tube bundle which is the heating line 2 at an interval similar to the interval between the tubes 2a constituting the tube bundle. In this way, the flow resistance when flowing between the tubes 2a and the flow resistance when flowing between the tubes 2a and the seal plate 7 are substantially equal, and each tube 2a constituting the heating line 2 has the same resistance. This is because the heat medium A can flow evenly. Further, if the gap between the seal plate 7 and the heating line 2 is larger than this, there is a problem that the flow of the heat medium A deviates from the heating line 2 as described above. On the other hand, if the gap is smaller, the heat medium A may stay here. There is. From this point as well, it is preferable that the distance is equal to the interval between the tubes 2a.

  And the heat exchanger 1 of a present Example has the characteristics in the point which comprised the rectifying plate 8 in the bottom part of the shell 3, and correct | amended the flow of the heat carrier A in this position. Hereinafter, the configuration and operation of the current plate 8 will be described with reference to FIGS. 1, 3, and 4.

  As shown in FIGS. 1 and 3, the rectifying plate 8 is disposed at a position facing the lower supply port 4 a at the bottom of the shell 3 so as to form an upward gradient when viewed from the lower supply port 4 a.

  As shown in FIG. 4, the flow of the heat medium A fed into the shell 3 from the lower supply port 4a proceeds along the horizontal direction, is bent near the inner wall on the opposite side, and changes direction at right angles. Head upward. At this time, when the flow of the heat medium A collides with the rectifying plate 8, the flow of the heat medium A is guided along the surface formed by the rectifying plate 8, and the flow direction is smoothly changed upward.

  Here, assuming that the rectifying plate 8 is not installed, when the heat medium A is changed in direction, the heat medium A is easily left behind from the flow and stays in the corner of the bottom of the shell 3 corresponding to the outside of the flow path. If heat exchange is performed with the heated fluid L in a state where the heat medium A stays in a certain place, the heat medium A may be frozen as a result of continuing to lose heat. In addition, the bottom of the shell 3 is close to the inlet 2b of the heating line 2, and a particularly low temperature fluid to be heated L that has not yet sufficiently exchanged heat with the heat medium A circulates. Easy part. In particular, when the heat exchanger 1 is used as a vaporizer that vaporizes the fluid L to be heated, the surrounding heat is rapidly taken away with the vaporization, and the temperature tends to decrease.

  Of course, in the present embodiment, as described above, the heat medium A is supplied from the lower supply port 4a disposed near the inlet 2b of the heating line 2 to prevent the heat medium A from being frozen. However, if stagnation occurs in the heat medium A, the heat medium A containing heat is not newly supplied in that portion, and the temperature of the heat medium A is easily lowered. And when a part of heat carrier A freezes, the crystal | crystallization grows and there exists a possibility that freezing may spread to the circumference | surroundings. Therefore, in this embodiment, the flow straightening plate 8 is disposed at this position to correct the flow of the heat medium A, the stagnation of the heat medium A is prevented, and freezing is prevented in advance. Even if it occurs, the new heat medium A flows one after another so that the growth is suppressed. At the same time, the heat exchange efficiency can be improved by smoothing the flow of the heat medium A.

  At this time, the rectifying plate 8 has a predetermined curvature from the upstream direction (here, horizontal direction) of the heat medium A toward the downstream direction (here, upward direction) that guides the heat medium A. Thus, it is preferable that they are arranged on a smoothly curved surface. Of course, the rectifying plate 8 can be configured as a flat plate, and even in such a case, it is considered that the rectifying plate 8 has a certain effect in suppressing the retention of the heat medium A. An angle close to a right angle is formed between the bottom portion or the inner wall of the shell 3 and may cause retention. Therefore, by forming the rectifying plate 8 as a plate having a curved surface that smoothly curves toward the direction in which the heat medium A is guided from the upstream side, the angle between the rectifying plate 8 and the bottom or inner wall of the shell 3 is as much as possible. The temperature of the heat medium A is made larger than that of the heat medium A so that the flow of the heat medium A can be smoothly changed in direction and the heat medium A is hardly retained.

  Furthermore, in the case of the present embodiment, the lower end portion of the seal plate 7 is curved to form a gradient portion 7a, and the flow of the heat medium A is rectified also by this gradient portion 7a.

  That is, the surface formed by the seal plate 7 is arranged so as to be orthogonal to the horizontal flow of the heat medium A in a plan view as described above. 4 is formed as a gradient portion 7a curved toward the lower supply port 4a, and forms a gradient in the same direction as the rectifying plate 8 upward as viewed from the lower supply port 4a. By doing so, the heat medium A sent from the lower supply port 4a is guided upward by the same action as the rectifying plate 8 described above, and heat is generated at the corner portion where the lower end portion of the seal plate 7 and the bottom surface of the shell 3 are in contact. The retention of the medium A is suppressed to prevent freezing and improve the heat exchange efficiency.

  Here, the flow path configuration of the heat medium A and the installation direction of the rectifying plate 8 and the gradient portion 7a are not limited to the example described above. The direction of the rectifying plate 8 and the gradient portion 7a can be variously changed depending on the shape of the flow path in the shell 3. For example, depending on the use of the heat exchanger and other conditions, a flow path configuration in which the heat medium supplied from below the shell is flowed upward and then turned sideways can be assumed. The gradient portion is arranged with a horizontal gradient when viewed from the supply port. Thus, the gradient of the current plate and the gradient portion should be set according to the flow path configuration of the heat medium in the shell so as to form a gradient toward the direction in which the heat medium is guided.

  In addition to the bottom portion of the shell 3, the gradient portion 7a of the rectifying plate 8 and the seal plate 7 can be provided around the baffle plate 6a and the baffle plate 6b, for example, as indicated by broken lines in FIG. That is, in the present embodiment, as described above, since the heat medium A is most likely to be frozen at the bottom of the shell 3 on the inlet 2b side of the heating line 2, the heat medium A is formed at this position by the rectifying plate 8 and the gradient portion 7a. However, even if the rectifying plate 8 and the gradient portion 7a are provided at other positions, there is no particular inconvenience. In addition to the bottom of the shell 3, for example, when there is a situation where it is desired to prevent the heat medium A from freezing in the vicinity of the baffle plate 6 a, the current plate 8 and the gradient portion 7 a can be appropriately installed.

  As described above, the heat exchanger 1 of the present embodiment includes the heating line 2 for circulating the fluid L to be heated and the shell 3 surrounding the heating line 2, and the heat medium A is contained in the shell 3. To heat exchange with the fluid L to be heated, and toward the position where the flow of the heat medium A is bent in the shell 3 as viewed from the upstream side of the heat medium A toward the direction of guiding the heat medium A. Since the rectifying plate 8 having a gradient is arranged, by guiding the flow of the heat medium A along the surface formed by the rectifying plate 8, the flow of the heat medium A can be smoothed and stay can be suppressed.

  Further, in the heat exchanger 1 of the present embodiment, the heat medium A supply port 4 is provided at a position on the inlet 2 b side of the heating line 2 in the shell 3, and the current plate is disposed at a position facing the supply port 4. 8 is provided, it is possible to suppress the stagnation of the heat medium A at a position where the heat medium A is in contact with the low-temperature fluid L, to prevent freezing and to improve the heat exchange efficiency.

  Moreover, in the heat exchanger 1 of the present embodiment, the heating line 2 is configured to extract the heated fluid L introduced from below, and the supply port 4 (lower supply port 4a) is connected to the shell 3. The rectifying plate 8 is provided at the bottom, and is arranged at the bottom of the shell 3 so as to form an upward slope when viewed from the supply port 4 (lower supply port 4a). Residence can be effectively suppressed in the type of heat exchanger 1 that is drawn upward.

  Further, in the heat exchanger 1 of the present embodiment, the rectifying plate 8 is configured to have a surface that smoothly curves from the upstream side of the heat medium A toward the direction in which the heat medium A is guided. This makes it possible to make the heat medium A more difficult to stay.

  Further, in the heat exchanger 1 of the present embodiment, the heating line 2 is configured as a heating channel group in which a plurality of channels (tubes 2 a) are bundled, and between the inner wall of the shell 3 and the heating line 2. A seal plate 7 that blocks the flow of the heat medium A, and at least a part of the seal plate 7 is inclined toward the direction in which the rectifying plate 8 guides the heat medium A when viewed from the upstream side of the heat medium A. Since the slope portion 7a is formed, the heat medium A can be prevented from staying by changing the shape of the seal plate 7 provided in the shell 3 in addition to the installation of the current plate 8.

  Therefore, according to the present embodiment, the heat medium can be suitably prevented from freezing with a simple configuration.

  The heat exchanger of the present invention is not limited to the above-described embodiments, and the gist of the present invention can be applied to, for example, not only vaporization of liquefied natural gas but also heating of liquefied ethylene. Of course, various changes can be made without departing from the scope.

1 Heat exchanger 2 Heating line (heating channel group)
2a Flow path (tube)
2b Inlet 3 Shell 4 Supply port 4a Supply port (lower supply port)
7 Seal plate 7a Gradient part 8 Current plate A Heat medium (antifreeze)
L Heated fluid (liquefied natural gas)

Claims (5)

A heating line for circulating a fluid to be heated inside, and a shell surrounding the heating line, and a heat medium is supplied into the shell to exchange heat with the fluid to be heated;
A heat exchanger in which a rectifying plate is disposed at a position where the flow of the heat medium is bent in the shell, and a gradient is formed in a direction in which the heat medium is guided as viewed from the upstream side of the heat medium.   2. The heat exchanger according to claim 1, wherein a heat medium supply port is provided at a position on the inlet side of the heating line in the shell, and the rectifying plate is disposed at a position facing the supply port. The heating line is configured to extract the fluid to be heated introduced from below from above,
The supply port is provided at a lower portion of the shell;
The heat exchanger according to claim 2, wherein the rectifying plate is disposed so as to have an upward slope when viewed from the supply port at a bottom portion of the shell.   The said baffle plate is a heat exchanger as described in any one of Claims 1-3 comprised by making the surface which curves smoothly toward the direction which guides a heat medium from the upstream of a heat medium.   The heating line is configured as a heating channel group in which a plurality of channels are bundled, and includes a seal plate that blocks a flow of a heat medium between the inner wall of the shell and the heating line, and at least a part of the seal plate Is a heat exchanger according to any one of claims 1 to 4, wherein the rectifying plate is formed as a gradient portion that is inclined toward a direction in which the heat medium is guided when viewed from the upstream side of the heat medium.

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