JP2754147B2 - Double tube open rack type vaporizer - Google Patents

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 and the like. Through which the liquefied natural gas is supplied to the inner 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. The present invention relates to a double-pipe open rack type vaporizer in which a flow difference is prevented from occurring in a fluid reversing section of a multiplicity of arranged double pipes.

[0002]

2. Description of the Related Art As an open rack type vaporizer for vaporizing liquefied natural gas (hereinafter referred to as LNG) by using a heat medium such as seawater, a single-pipe open rack type vaporizer has been mainly used. The single-pipe 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 pipes are connected, and a trough disposed on both upper sides of the heat exchange panel. As the LNG rises in the pipe, it is heated and vaporized by the seawater as a heat medium outside the pipe, and is evaporated from the upper header tank provided at the upper end of the heat exchange panel as natural gas (NG). Is provided.

In the single-pipe open rack type vaporizer, heat is directly exchanged between seawater as a heat medium and cryogenic LNG through a single-pipe wall of the heat exchange panel. If ice accretion occurs on the surface and there is a drift in seawater sprinkling flow rate, this ice accretion will also be unbalanced, causing a difference in the amount of shrinkage of each heat exchange tube and increasing the thermal stress. .

[0004] Therefore, the applicant has formed a heat exchange panel by connecting 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 of the upper and lower sides of the heat exchange tubes. The LNG introduced from the one end into the inner pipe and flowed down from the other end is moved between the outer pipe and the inner pipe and moved between the outer pipe and the inner pipe, and the seawater flows into the NG outlet header tank of the outer pipe during the U-shaped flow. A double-pipe open rack vaporizer has been proposed (JP-A-4-254096) in which heat is input in the order of → outer pipe → NG → inner pipe → LNG. The above-mentioned double-pipe open rack type vaporizer can reduce the amount of seawater by reducing icing which is unavoidable in the conventional apparatus, reduce the amount of pumps used, and prevent flow rate and calorie hunting. , LNG and NG flows are stabilized.

As shown in FIG. 2, a double-pipe structure has been proposed as a configuration that can prevent icing near the LNG inlet header tank, more efficiently arrange the LNG inlet / outlet header tank, and 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 as free ends, and watering troughs 9 and 9 are disposed opposite to each other on the upper portion of the panel so that water can be sprayed. The inner pipe 6 extends through the NG outlet header tank 4 provided at the upper end of the NG outlet header tank 8 and the LNG inlet header tank 8 is disposed above the NG outlet header tank 4 to introduce a liquefied gas into the inner pipe 6. The fluid that has exited the inner tube 6 within the outer tube 2 at the lower end of the closed heat exchange tube 1 can be inverted, and the fluid that moves upward in the annular passage between the outer tube 2 and the inner tube 6 after the inversion, and the outer surface of the outer tube 2 Water exchange and heat exchange with liquefied gas in 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 extends through the NG outlet header tank 4 provided at the upper end portion so that the LNG is located above the NG outlet header tank 4. Since the inlet and outlet header tanks 4 and 8 can be arranged in the axial direction of the heat exchange tubes by disposing the inlet header tank 8, the installation space can be reduced and the space efficiency is excellent. As shown in FIG. 2, the lower end of the inner tube 6, which is a fluid reversal portion, has a configuration in which the fluid is reversed by providing a certain space between the lower end and the inner surface 3 of the outer tube 2.
However, this interval is limited to the upper outlet header tank 4 of the inner pipe 6.
Since it is determined by the mounting accuracy of the joint with the pipe, it is difficult to maintain the heat at a constant level in each of the multiple pipes forming the heat exchange panel. And it is feared that the fluid does not divide evenly.

According to the present invention, in the above-described double-pipe 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 between the inner pipe and the upper outlet header. It is an object of the present invention to provide a double-pipe open rack type vaporizer having a configuration capable of uniformly dividing a fluid flow in a reversal portion of a fluid formed in a pipe.

[0008]

SUMMARY OF THE INVENTION The present invention provides a heat exchange panel in which a large number of heat exchange tubes having a double-pipe structure are suspended and supported with a lower end thereof being a free end. The inner pipe extends through the outlet header tank provided at the upper end of the heat exchange pipe, and the inlet header tank is placed above the outlet header tank to liquefy inside the inner pipe. Introduces gas, makes it possible to reverse the fluid that has exited the inner pipe in the outer pipe at the lower end of the closed heat exchange pipe, and fluid that rises and moves in the annular passage between the outer pipe and the inner pipe after inversion, and watering on the outer surface of the outer pipe And a heat exchanger capable of exchanging heat with the liquefied gas in the inner pipe and allowing the vaporized gas heated and vaporized to be discharged from the outlet header tank. The fact that a hole for fluid reversal was provided on the outer circumference A double-pipe open rack type vaporizer to symptoms.

Further, the present invention also proposes a double-pipe open rack type vaporizer characterized in that the lower end face of the inner pipe is in contact with the closed inner face of the outer pipe in the above construction. Further, the present invention also proposes a double-pipe open rack type vaporizer in which the lower end face of the inner pipe is closed in the above-described configuration.

[0010] In the present invention, the double tube structure is LNG.
Can flow down from the upper end of the inner pipe to be inverted from the lower end of the opening, and the annular passage between the outer pipe and the inner pipe can adopt any configuration as long as NG can be raised. A finned tube having fins protruded can be used. Further, the inner pipe and the outer pipe may be provided with cuts or irregularities on the inner surface to increase the heat transfer area. The number and shape of the fluid reversing holes provided on the outer periphery of the lower end of the inner pipe are appropriately selected according to the dimensions of the pipe and the passage, the fluid flow rate, and the like. Various configurations can be adopted for the closing member at the lower end of the inner tube,
For example, in addition to a simple plug, a structure having an extended portion close to the inner diameter of the outer tube and also serving as a steadying member for the inner tube may be employed.

[0011]

The open rack type vaporizer according to the present invention has the following features.
The heat exchange tube has a double structure, liquefied natural gas is supplied to the inner tube through the outlet header provided at the upper end, and when the vaporized gas is led out from the lower portion of the inner tube to the upper portion of the outer tube by a U-shaped flow. 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 reverses.
In addition to the effect that there is no difference in the shape of the fluid reversal part due to the mounting error of the joint part at the time of manufacture, the manufacture is facilitated and the manufacturability is improved. Also, by contacting or closing the lower end of the inner pipe with the closed inner surface of the outer pipe, the fluid flows out only from the fluid inversion hole provided on the outer circumference of the lower end of the inner pipe and is inverted. In this case, the shape of the passage of the fluid reversal section is uniform, 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, thereby making the size of the deviated passage non-uniform.

[0012]

【Example】

Embodiment 1 FIGS. 1A to 1C are longitudinal sectional explanatory views of a main part showing a configuration of a fluid reversing portion of a heat exchange tube according to the present invention applied to a double tube open rack type vaporizer. In the double-pipe open rack type vaporizer to which the present invention is applied, a heat exchange panel is formed by arranging a large number of heat exchange tubes 1 having a double-pipe structure shown in FIG. An NG outlet header tank 4 is provided at the upper end of the panel, that is, at the upper end of each heat exchange tube 1. The water exchange troughs 9 and 9 are arranged on both upper surfaces of the heat exchange panel so as to face each other, and overflow water flows down on the panel surface.

The outer tube 2 constituting each heat exchange tube 1 is a finned tube having a star fin protruding from the outer peripheral surface, has a required length and inner diameter, is closed at the lower end, and is horizontally arranged at the upper end. The NG outlet header tank 4 is connected to the inner pipe 6, and the inner pipe 6 has a predetermined outer diameter so as to form an annular passage having a predetermined width between the inner pipe 6 and the inner surface of the outer pipe 2 provided with a number of axial grooves. The lower end of the inner tube 3 is desirably inserted into the outer tube 2 and its lower end is desired. The upper end of the inner tube 6 extends upward through the NG outlet header tank 4 to reduce 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 tube 6 of each heat exchange tube 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 tube 6. The upper end of the tubular member 5 and the inner tube 6 are fixedly welded to each other so as to form a cap portion.

The fluid reversal part which is a feature of the present invention is shown in FIG.
As shown in FIG. 2A, the lower end of the inner pipe 6 is in contact with the inner surface 3 of the lower end of the outer pipe. Formed
The fluid flowing down the inner tube 6 flows out of the hole 10 and rises up and down between the inner surface of the outer tube 2. In order to make the lower end of the inner tube 6 abut against the inner surface 3 of the lower end of the outer tube, the upper end of the tubular member 5 and the inner tube 6
When joining, the joining work can be started only by checking the contact of the lower end of the inner tube 6, and the work is easy. In addition, FIG.
In the example shown in the figure, a plug 12 for closing is inserted into the lower end of the opening of the inner tube 6 as desired on the inner surface 3 at the lower end of the outer tube, and holes 11 for fluid reversal are radially formed at a plurality of positions on the outer peripheral surface of the lower end. The fluid flowing down the inner pipe 6 flows out of the hole 11 and rises up and down between the inner pipe 6 and the inner surface of the outer pipe 2. In the example shown in FIG. 1C, a plurality of holes 11 for fluid reversal are formed in the outer peripheral surface of the lower end portion of the inner tube 6 in a radial manner.
However, in place of the plug 12, a plug 13 having an extension close to the inner diameter of the outer tube is inserted, and the flange serves to prevent the inner tube from swaying. At this time, the joining operation to the header can be started only by confirming the contact of the plug 13 at the lower end of the inner tube 6 with the inner surface 3 of the lower end of the tube.

In the above configuration, the inner pipe 6 is connected to the LNG inlet header tank 8 disposed at the top of the heat exchange panel.
LNG is supplied to the NG outlet header tank 4 through the curved portion 7, NG is supplied from the lower end of the inner pipe 6 into the outer pipe 2, and the annular passage in the pipe is raised to move the NG from the upper end of the outer pipe 2 to the outside. , The pressure loss in the pipe increases, the gas flow becomes stable, and seawater as a heat medium and cryogenic L
Since heat is not directly exchanged with NG but is exchanged through NG in the annular passage, icing on the surface of the outer tube 2 is reduced, and the evaporator can be downsized by increasing the heat transfer area. it can. Furthermore, the amount of seawater as a heat medium to be supplied can be reduced by reducing icing, the power consumption of the seawater pump can be significantly reduced, and the LNG inlet header tank 8 has a watering trough 9, By being located above 9, heat input of seawater can be prevented, and flow hunting and calorie hunting to each heat exchange tube can be prevented.

[0016]

As is apparent from the above embodiment, the open rack type vaporizer according to the present invention has a double-tube heat exchange tube, and penetrates the inner tube through the outlet header tank provided at the upper end. When the inlet header tank is arranged above the outlet header tank, 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 a tubular member that is vertically installed in this through hole. Adopts a cap structure that is fixed to the upper end of the tubular member.However, since a hole for fluid reversal is provided on the outer periphery of the lower end of the inner tube, fluid flows out from the side wall of the inner tube and is reversed. In addition to the effect that the difference in the shape of the fluid reversing portion does not occur due to the mounting error of the joining portion at the time, the manufacturing is improved because the manufacturing becomes easy. Also, by closing the lower end of the inner tube or abutting against the inner surface of the outer tube, the fluid flows out only from the hole for fluid reversal provided on the outer periphery of the lower end of the inner tube and reverses. The passage shape of the fluid reversing part is standardized, and the fluid flow becomes uniform. In addition, it is possible to prevent the lower end of the inner tube from moving due to vibration or the like, thereby making the size of the unbalanced passage non-uniform.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view showing a configuration of a heat exchange tube constituting the heat exchange panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchange tube 2 Outer tube 3 Inner surface of lower end of outer tube 4 NG outlet header tank 5 Cylindrical member 6 Inner tube 7 Curved portion 8 LNG inlet header tank 9 Trough for watering 10,11 Hole 12,13 Plug

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiyasu Miura 38-37-402, Shirahata-kami-cho, Kanagawa-ku, Yokohama-shi, Kanagawa-ken (72) Inventor Yoshiro Tonoike 1-10 Fuso-cho, Amagasaki-shi, Hyogo Sumitomo Seimitsu Industry Co., Ltd. (56) References JP-A-3-286990 (JP, A) Jikku Sho 61-43109 (JP) , Y2)

Claims (3)

(57) [Claims] 1. A heat exchange panel in which a large number of heat exchange tubes of a double pipe structure are suspended and supported with their lower end portions being free ends, and a watering trough is disposed opposite to the upper portion of the panel so that water can be sprayed. 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 liquefied gas is introduced into the inner pipe to block the heat. The fluid that has exited the inner pipe is made reversible in the outer pipe at the lower end of the exchange pipe, and heat exchanges with the fluid that rises and moves in the annular passage between the outer pipe and the inner pipe after the reversal, watering the outer surface of the outer pipe, and liquefied gas in the inner pipe. In the double-pipe open rack type vaporizer in which the vaporized gas whose temperature has been raised and vaporized can be discharged from the outlet header tank, a hole for fluid inversion is provided on the outer periphery of the lower end of the inner pipe. Characterized by a double tube open rack type vaporizer. 2. The double-pipe open rack vaporizer according to claim 1, wherein a lower end face of the inner pipe is in contact with a closed inner face of the outer pipe. 3. The double-pipe open rack type vaporizer according to claim 1, wherein a lower end face of the inner pipe is closed.