JPH07159061A - Doube-pipe open-rack vaporizer - Google Patents

Abstract

PURPOSE:To evenly divide a fluid flow at a turning point of the fluid. CONSTITUTION:Liquefied natural gas is caused to flow from the lower end of an internal tube 6 upwardly through an annular passage in an external tube 2, in a U-shaped flow pattern, wherein holes 10, 11 are provided on the outer periphery of the lower end of the tube 6 to reverse the flow of fluid so that the fluid flows out of the side wall of the tube 6 and is caused to flow reversely, and hence differences in the shape of the turning point of the fluid due to errors in the fabrication of a joint at the manufacture thereof are not generated, thereby facilitating the manufacturing thereof. Further the lower end of the tube 6 is closed or it is brought into contact with the closed inner surface 3 of the external tube, whereby the fluid flows out only through the holes so as to be reversed so that the fluid flows evenly, and the lower end of the tube 6 is prevented from being moved by vibration or the like, thereby preventing the dimension of the fluid passage from becoming uneven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open rack type vaporizer for vaporizing liquefied natural gas with a heat medium such as seawater, which has a double pipe structure as a heat exchange pipe and an outlet header provided at the upper end. The liquefied natural gas is supplied to the inner pipe through the pipe and the vaporized gas is led out from the lower part of the inner pipe to the upper part of the outer pipe by a U-shaped flow. In particular, a hole for fluid reversal is provided at the outer periphery of the lower end of the inner pipe. The present invention relates to a double-tube open rack type vaporizer in which a difference in flow is prevented from occurring in a fluid reversal section of a large number of double-tubes arranged.

[0002]

2. Description of the Related Art As an open rack type vaporizer for vaporizing liquefied natural gas (hereinafter referred to as LNG) using a heat medium such as seawater, a single pipe open rack type vaporizer has hitherto been the mainstream. The single-tube open rack type vaporizer supplies LNG from a lower header tank provided at the lower end of a heat exchange panel in which a large number of single-tube heat exchange tubes are connected, and troughs arranged on both upper sides of the heat exchange panel. As LNG rises in the pipe, the seawater sprinkled from it heats and vaporizes by seawater, which is a heat medium outside the pipe, and is discharged as natural gas (hereinafter referred to as NG) from the upper header tank provided at the upper end of the heat exchange panel. It is configured to be supplied to.

In the single-tube open rack type vaporizer, seawater, which is a heat medium, and cryogenic LNG directly exchange heat with each other through the single tube wall of the heat-exchange panel, so that the outside of the tube, that is, the heat-exchange panel. If ice accretion occurs on the surface and there is a drift in the flow rate of seawater, this ice accretion also becomes unbalanced, and the contraction amount of each heat exchange tube becomes different, resulting in an increase in thermal stress. .

Therefore, the Applicant has formed a heat exchange panel by arranging a large number of heat exchange tubes having a double tube structure, and has an LNG inlet header tank and an NG outlet header tank on one side of the upper or lower side of the heat exchange tube. The LNG that has been placed and introduced into the inner pipe from one end is inverted from the other end to move between the outer pipe and the inner pipe, and the seawater is fed between the outer pipe and the NG outlet header tank of the outer pipe during the U-shaped flow. A double-tube open rack type vaporizer having a structure in which heat is input in the order of → outer tube → NG → inner tube → LNG was proposed (JP-A-4-254096). The double-tube open rack type vaporizer described above can reduce the amount of seawater by reducing icing, which is inevitable with conventional equipment, reduce the amount of pumping pump used, and prevent flow and calorie hunting. , LNG and NG flows have the advantage of being stable.

Further, as shown in FIG. 2, a double pipe structure is adopted to prevent ice from accumulating in the vicinity of the LNG inlet / outlet header tank and to make the layout of the LNG inlet / outlet header tank more efficient to reduce the installation space. A heat exchange panel is formed by suspending and supporting a large number of heat exchange tubes with their lower ends being free ends, and sprinkling troughs 9, 9 are disposed facing each other on the upper part of the panel to enable water sprinkling. The NG outlet header tank 4 provided at the upper end of the NG outlet header tank 4 and the LNG inlet header tank 8 is arranged above the NG outlet header tank 4 to introduce the liquefied gas into the inner pipe 6. The fluid exiting the inner tube 6 in the outer tube 2 at the lower end of the closed heat exchange tube 1 can be reversed, and the fluid moving upward in the annular passage between the outer tube 2 and the inner tube 6 after reversing and the outer surface of the outer tube 2 Water can be exchanged and heat can be exchanged with the liquefied gas in the inner pipe 6. Ungated proposed vaporized derivable with dual pipe open rack type vaporizer which no Atsushi Nobori is caused vaporized gas from NG outlet header tank 4.

[0006]

The heat exchange pipe has a double pipe structure, and the inner pipe 6 is extended through the NG outlet header tank 4 provided at the upper end to extend the LNG above the NG outlet header tank 4. Since the inlet header tank 8 can be arranged and the outlet and the inlet header tanks 4 and 8 can be arranged in the axial direction of the heat exchange tube 1, the installation space can be reduced and the space efficiency is excellent. As shown in FIG. 2, the lower end portion of the inner pipe 6, which is a fluid reversal portion, has a structure in which the fluid is reversed by providing a constant space between the inner pipe 6 and the lower end inner surface 3 of the outer pipe 2.
However, this interval is the upper outlet header tank 4 of the inner pipe 6
Since it is determined by the mounting accuracy of the joint with the heat exchange panel, it becomes difficult to keep it constant in each of the multiple double tubes forming the heat exchange panel. There is a concern that the fluid will not be evenly distributed.

According to the present invention, in the above-mentioned double-tube open rack type vaporizer, the gap between the lower end of the inner pipe and the inner surface of the lower end of the outer pipe is irrespective of the mounting accuracy of the joint with the upper outlet header of the inner pipe. It is an object of the present invention to provide a double-tube open rack type vaporizer having a configuration capable of evenly dividing the fluid flow in the inversion portion of the fluid formed in the above.

[0008]

SUMMARY OF THE INVENTION The present invention forms a heat exchange panel in which a large number of heat exchange tubes having a double-tube structure are suspended from each other with their lower end portions being free ends, and a water sprinkling trough is provided above the panel. Are arranged opposite to each other so that water can be sprinkled, the inner pipe is extended through the outlet header tank provided at the upper end of the heat exchange pipe, and the inlet header tank is arranged above the outlet header tank to liquefy in the inner pipe. It is possible to invert the fluid that has exited the inner tube inside the outer tube at the lower end of the closed heat exchange tube by introducing gas, and after moving, the fluid that moves upward in the annular passage between the outer tube and the inner tube and the water spray on the outer surface of the outer tube In the double pipe open rack type vaporizer, which is capable of exchanging heat with the liquefied gas in the inner pipe and is capable of discharging the vaporized and heated vaporized gas from the outlet header tank, the lower end of the inner pipe That there is a hole for fluid reversal on the outer circumference A double-pipe open rack type vaporizer to symptoms.

The present invention also proposes a double-tube open rack type vaporizer in which the lower end surface of the inner tube is in contact with the closed inner surface of the outer tube in the above-mentioned structure. Further, the present invention also proposes a double pipe type open rack type vaporizer characterized in that the lower end surface of the inner pipe is closed in the above configuration.

In the present invention, the double tube structure is LNG.
Can flow downward from the upper end of the inner pipe and reverse from the lower end of the opening, and any structure can be adopted as long as NG can rise in the annular passage between the outer pipe and the inner pipe. A finned tube with fins protruding can be used. Furthermore, both the inner tube and the outer tube may be provided with cuts or irregularities on their inner surfaces to increase the heat transfer area. The number and shape of the fluid inversion holes provided on the outer periphery of the lower end of the inner tube are appropriately selected according to the dimensions of the tubes and passages, the fluid flow rate, etc., but it is necessary to arrange them so that the fluid flow is uniform. Various configurations can be adopted for the closing member at the lower end of the inner pipe,
For example, in addition to a simple plug, an extension portion close to the inner diameter of the outer tube may be provided, which also serves as a steady stop for the inner tube.

[0011]

The open rack type vaporizer according to the present invention is
When the heat exchange pipe has a double structure and the liquefied natural gas is supplied to the inner pipe through the outlet header provided at the upper end and the vaporized gas is discharged from the lower part of the inner pipe to the upper part of the outer pipe by U-shaped flow By providing a hole for fluid inversion on the outer periphery of the lower end of the inner pipe, the fluid flows out from the side wall of the inner pipe and is inverted,
In addition to the effect that the shape of the fluid reversal portion does not differ due to the attachment error of the joint portion at the time of manufacturing, the manufacturing is facilitated and the manufacturability is improved. Further, by contacting or closing the lower end of the inner pipe with the closed inner surface of the outer pipe, the fluid flows out and inverts only from the hole for fluid reversal provided on the outer periphery of the lower end of the inner pipe. The passage shape of the fluid reversal part is uniformed, and the fluid flow becomes uniform. further,
It is possible to prevent the lower end of the inner tube from moving due to vibration or the like and causing the uneven passage dimension to become uneven.

[0012]

【Example】

Example 1 A to C of FIG. 1 are longitudinal explanatory views of a main part showing a configuration of a fluid reversal section of a heat exchange tube according to the present invention applied to a double tube type open rack type vaporizer. A double pipe type open rack type vaporizer to which the present invention is applied forms a heat exchange panel by arranging a large number of heat exchange pipes 1 having a double pipe structure shown in FIG. The NG outlet header tank 4 is provided at the upper end of the panel, that is, the upper end of each heat exchange tube 1. Sprinkler troughs 9, 9 are arranged opposite to each other on both upper surfaces of the heat exchange panel so that overflow water flows down to the panel surface.

As the outer tube 2 constituting each heat exchange tube 1, here, a finned tube having an outer peripheral surface projecting a star fin is used, the lower end is closed with a required length and inner diameter, and the upper end is arranged horizontally. The inner pipe 6 has a predetermined outer diameter so as to form an annular passage of a predetermined width between the inner pipe 6 and the inner surface of the outer pipe 2 having a large number of axial grooves. The outer pipe 2 is loosely inserted and the lower end of the outer pipe 3 is desired to have its lower end, and the upper end of the inner pipe 6 penetrates the NG outlet header tank 4 and extends upward to the outside for heat shrinkage. A curved portion 7 for absorbing is formed and is connected to an LNG inlet header tank 8 horizontally arranged vertically above the NG outlet header tank 4. Further, the connecting portion between the inner pipe 6 of each heat exchange pipe 1 and the NG outlet header tank 4 has a through hole provided at the top of the NG outlet header tank 4 having a predetermined inner diameter larger than the outer diameter of the inner pipe 6. The inner pipe is loosely inserted in the tubular member 5 arranged upright, and the upper end of the tubular member 5 and the inner pipe 6 are fixed by welding to form a cap portion.

The fluid reversing portion which is a feature of the present invention is shown in FIG.
As indicated by A, the lower end of the inner pipe 6 is in contact with the inner surface 3 of the lower end of the outer pipe, and the outer peripheral surface of the lower end of the inner pipe 6 is provided with a plurality of radial cutouts 10 for fluid inversion. Formed,
The fluid flowing down the inner pipe 6 flows out from the hole 10 and reverses and rises between the inner surface of the outer pipe 2. Since the lower end of the inner pipe 6 is brought into contact with the inner surface 3 of the lower end of the outer pipe, the upper end of the tubular member 5 and the inner pipe 6
At the time of joining with, the joining work can be started only by confirming the contact of the lower end of the inner pipe 6, and the work is easy. Also, B in FIG.
In the example shown in (1), a closing plug 12 is fitted into the lower end of the opening of the inner pipe 6 desired in the inner surface 3 of the lower end of the outer pipe, and holes 11 for fluid inversion are radially provided at a plurality of locations on the outer peripheral surface of the lower end. The fluid flowing down the inner tube 6 flows out from the hole 11 and inverts and rises between the inner surface of the outer tube 2 and the inner surface of the outer tube 2. In the example shown in C of FIG. 1, a plurality of fluid inversion holes 11 are radially formed on the outer peripheral surface of the lower end portion of the inner pipe 6, and the above B
Although the configuration is similar to that of the example shown in FIG. 10, a plug 13 having an extending portion close to the inner diameter of the outer tube is fitted in place of the plug 12, and the flange serves as a steady stop for the inner tube and At this time, the joining work to the header can be started only by confirming the contact of the plug 13 at the lower end of the inner pipe 6 with the inner surface 3 of the lower end of the pipe.

In the above structure, the inner pipe 6 is inserted from the LNG inlet header tank 8 arranged at the top of the heat exchange panel.
LNG is supplied to the outer pipe 2, passes through the NG outlet header tank 4 through the curved portion 7, supplies NG from the lower end of the inner pipe 6 into the outer pipe 2, and ascends the annular passage in the pipe to the outside from the upper end of the outer pipe 2. Since it is a U-shaped flow that goes out, the pressure loss in the pipe increases, the gas flow becomes stable, and the heat medium seawater and cryogenic L
Since it does not directly exchange heat with the NG but exchanges heat via the NG in the annular passage, it is possible to reduce ice adhesion to the surface of the outer tube 2 and to reduce the size of the vaporizer by increasing the heat transfer area. it can. Further, it is possible to reduce the amount of seawater as a heat medium to be supplied by reducing ice accretion, and it is possible to significantly reduce the electric power consumption of the pump for pumping seawater, and the LNG inlet header tank 8 has a sprinkling trough 9, By locating above 9 the heat input of seawater can be prevented and the flow hunting and calorie hunting to each heat exchange tube can be prevented.

[0016]

As is apparent from the above-described embodiment, the open rack type vaporizer according to the present invention has a heat exchange tube having a double tube structure and an inner tube penetrating through an outlet header tank provided at the upper end. When the inlet header tank is arranged above the outlet header tank by extending the above, the through hole of the outlet header tank is made larger than the outer diameter of the inner pipe, and the inner pipe is loosely inserted into the tubular member standingly arranged in this through hole. The structure of the cap that sticks to the upper end of the tubular member is adopted.However, by providing a hole for fluid reversal on the outer periphery of the lower end of the inner pipe, the fluid flows out from the side wall of the inner pipe and is reversed, so it is manufactured. At the same time, there is no difference in the shape of the fluid reversal portion due to the attachment error of the joint portion, and the manufacturing is facilitated, which improves the manufacturability. Further, by closing the lower end of the inner pipe or abutting the closed inner surface of the outer pipe, the fluid flows out and inverts only from the hole for fluid reversal provided on the outer periphery of the lower end of the inner pipe. The passage shape of the fluid reversing portion is made uniform, and the fluid flow becomes uniform. Furthermore, it is possible to prevent the lower end of the inner pipe from moving due to vibration or the like and causing the uneven passage dimension to become uneven.

[Brief description of drawings]

FIG. 1A to FIG. 1C are longitudinal explanatory views of a main part showing a configuration of a fluid inversion section of a heat exchange tube according to the present invention applied to a double tube type open rack type vaporizer.

FIG. 2 is a vertical cross-sectional explanatory view showing a configuration of a heat exchange tube which constitutes a heat exchange panel.

[Explanation of symbols]

 1 Heat Exchange Tube 2 Outer Tube 3 Outer Tube Lower End Inner Surface 4 NG Outlet Header Tank 5 Tubular Member 6 Inner Tube 7 Curved Part 8 LNG Inlet Header Tank 9 Water Sprinkling Trough 10, 11 Hole 12, 13 Plug

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahide Yamamoto 1-48-6-1402 Higashiikebukuro, Toshima-ku, Tokyo (72) Inventor Toshiyasu Miura 38-37-402 (72) Shirahatakami-cho, Kanagawa-ku, Yokohama, Kanagawa Inventor Hitonobu 1-10 Fuso-cho, Amagasaki-shi, Hyogo Prefecture Sumitomo Precision Industries Ltd. (72) Inventor Yoshiro Tonoike 1-10 Fuso-cho, Amagasaki-shi Hyogo Sumitomo Precision Industries Ltd.

Claims (3)

[Claims] 1. A heat exchange panel in which a plurality of double-tube heat exchange tubes are suspended from each other with their lower ends free ends to form a heat exchange panel, and a water sprinkler trough is disposed facing the upper part of the panel to enable water sprinkling. The inner pipe extends through the outlet header tank provided at the upper end of the heat exchange pipe, the inlet header tank is arranged above the outlet header tank, and the liquefied gas is introduced into the inner pipe to block heat. The fluid flowing out of the inner pipe can be reversed inside the outer pipe at the lower end of the exchange pipe, and after the reversal, the fluid moving upward in the annular passage between the outer pipe and the inner pipe, the water spray on the outer surface of the outer pipe and the heat exchange with the liquefied gas inside the inner pipe In a double-tube open rack type vaporizer capable of discharging vaporized gas whose vaporization temperature has risen from the outlet header tank, a hole for fluid reversal was provided on the outer periphery of the lower end of the inner pipe. A double tube open rack type vaporizer featuring. 2. The double-tube open rack type vaporizer according to claim 1, wherein the lower end surface of the inner tube is in contact with the closed inner surface of the outer tube. 3. The double pipe type open rack type vaporizer according to claim 1, wherein the lower end surface of the inner pipe is closed.