JPH03286991A - Double pipe type open rack gasifying apparatus - Google Patents

Abstract

PURPOSE:To reduce icing by parallelly erecting a large number of heat exchange pipes each having a double pipe structure in which a heat transfer promoting body is inserted to form a heat exchange panel to allow liquefied gas to flow in the inner pipe of each heat exchange pipe from one end thereof and moving the formed gas reversed at the opening end of the inner pipe opposed to the closed end of the outer pipe of each heat exchange pipe through the annular passage between the outer and inner pipes. CONSTITUTION:A large number of heat exchange pipes each having a double pipe structure are arranged in parallel to constitute a heat exchange panel which is, in turn, arranged vertically. A ribbon-shaped heat transfer promoting body 30 to which a required twist is applied is inserted in the inner pipe of each heat exchanger pipe and a spiral heat transfer promoting body 31 having a required pitch is inserted in the annular passage between the outer and inner pipes 10, 11 of the heat exchange pipe. Supplied LNG flows downwardly through the inner pipe 11 from an inlet header tank 12 and heated by NG before it reaches the inner bottom of the outer pipe 10 from the lower opening end of the inner pipe 11 to be reversed and partially gasified while the gasified LNG is further heated during the rising through the annular passage to be led out to an NG outlet header tank 14 as NG of room temp. through the NG outlet pipe 13 connected to the upper part of the outer pipe 10.

Description

Detailed Description of the Invention Field of Application This invention relates to an open rack type vaporizer for vaporizing liquefied natural gas using a heat medium such as seawater, in which the heat exchange tube has a double-tube structure having a heat transfer promoter. The structure is such that liquefied natural gas is supplied from the upper end to the inner pipe and vaporized gas is led out to the upper part of the outer pipe in a U-shaped flow, preventing flow hunting, reducing swimsuits, reducing the amount of seawater, This invention relates to a double-pipe open rack type vaporizer that stabilizes gas flow.

BACKGROUND ART Conventionally, single-tube open rack type vaporizers have been mainstream as open rack type vaporizers for vaporizing liquefied natural gas (hereinafter referred to as LNG) using a heat medium such as seawater.

As shown in Figure 6, the single-tube open rack type vaporizer consists of a heat exchange panel (1
) LNG from the lower header tank (2) installed at the lower end of the
As the LNG rises inside the pipe, it is heated and vaporized by the seawater, which is a heat medium outside the pipe, and heat is released. Natural gas (hereinafter referred to as NG) is removed from the upper header tank (4) installed at the upper end of the replacement panel (1).
It consists of a configuration that is supplied externally as a.

As mentioned above, the single-tube open rack type vaporizer has a simple structure and is easy to manufacture. For heat exchange, outside the tube, that is, heat exchange panel (1)
There is a problem of increasing swimsuit formation on the surface.

To be more specific, if there is an imbalance in the water flow rate supplied to each heat exchange tube in the heat exchange panel (1), an imbalance will occur in the height of the swimsuit on the outside surface of the tube.As the LNG flow rate increases, the swimsuit height will increase. The amount of imbalance increases.

As a result, the temperature of each heat exchange tube itself becomes non-uniform, a difference occurs in the amount of contraction of each heat exchange tube, and thermal stress increases, which greatly limits the ability to improve the performance of the vaporizer.

Therefore, in order to prevent the unbalance of the swimsuit on the surface of the heat exchange panel (1), measures have been proposed in the past, such as making the amount of water sprinkled on each heat exchange tube uniform and relieving thermal stress. However, the fundamental drawbacks of the single-tube open rack type vaporizer could not be overcome.

One possible way to solve this problem is to use a double-tube heat exchange tube to heat the LNG indirectly.
There are many problems such as poor heat transfer efficiency, the temperature of NG is lowered by cryogenic LNG, and it is necessary to heat the low-temperature gas leaving the vaporizer to supply room-temperature gas. The optimal configuration for LNG vaporization equipment, such as selecting the installation location and using the passages between the inner and outer tubes in consideration of heat transfer efficiency, has not been proposed.

Purpose of the Invention The present invention provides a vaporizer in which the heat exchange tube has a double tube structure in order to reduce the problem of swimsuits on the surface of the heat exchange panel, which has been a problem in conventional single-tube open rack type vaporizers. The aim is to provide a double-pipe open rack type vaporizer that prevents flow rate hunting, reduces swimwear, reduces seawater volume, and stabilizes gas flow.

Summary of the Invention This invention comprises forming a heat exchange panel by connecting a large number of heat exchange tubes with a double pipe structure, and arranging a liquefied gas inlet header tank and a vaporized gas outlet header tank at the upper or lower part of the heat exchange panel. A water sprinkling trough is installed at the top of the panel to allow liquefied gas to flow in from one end of the inner tube, and to invert the vaporized gas at the open end of the inner tube opposite the closed end of the outer tube between the outer tube and the inner tube. Alternatively, liquefied gas can be introduced from one end of the inner tube and gas-liquid can be mixed in the outer tube through a small hole provided on the outer periphery of the other closed end of the inner tube. and a configuration in which the vaporized gas is guided through an annular passageway between an outer tube and an inner tube, and a heat transfer accelerator is inserted into either the inner tube or the annular passageway. This is a heavy tube open rack type vaporizer.

The double-tube open rack type vaporizer according to the present invention can have various configurations, but to give an example in detail, the inlet header tank provided at the upper end or lower end of the heat exchange tube of the heat exchange panel into the inner tube Introducing liquefied gas to
A small hole is provided on the outer periphery of the inner tube at the other end of the block opposite to the inlet header tank, allowing gas and liquid to mix inside the outer tube, and the fluid moving upward or downward through the annular passage between the outer tube and the inner tube and the outside. In a configuration that enables water sprinkling on the outside of the pipe and heat exchange with the liquefied gas in the inner pipe, the vaporized gas that has been vaporized and heated can be led out from the outlet header tank connected to the outer pipe on the artificial header tank side. It has a structure in which a heat transfer promoter is inserted into one of the passages.

In addition, an inner tube shorter than the outer tube is coaxially inserted into the outer tube, which has one end closed and an outlet header tank provided at the other end, so that its open end faces the closed end of the outer tube, and the inner tube is connected to the inlet header tank. A heat exchange panel is formed by forming a heat exchange panel by arranging a large number of heat exchange tubes with a double-tube structure in which the closed ends of the tubes are placed at a required distance from the outlet header tank, and the header tank is placed at the top or bottom of the tube and is installed vertically. A sprinkler trough is installed on the top of the panel to enable heating, and liquefied gas is introduced into the inner pipe from an inlet header tank connected to the closed end of the inner pipe, and a water trough is installed on the outer periphery of the other closed end of the inner pipe. It is possible to mix gas and liquid in the outer tube through small holes, and to exchange heat with the fluid that moves upward or downward through the annular passage between the outer tube and the inner tube, and with the water sprinkled on the outer surface of the outer tube and the liquefied gas in the inner tube. In a configuration in which vaporized gas is led out from an outlet header tank connected to the end of the outer tube, a heat transfer promoter is inserted into either the inner tube or the annular passage.

Structure of the Invention The present invention was developed as a result of various studies aimed at creating an open rack type vaporizer with a double tube structure that reduces the number of swimsuits attached to the heat exchange panel as in conventional open rack type vaporizers. A heat exchange panel is formed by connecting a large number of heat exchange tubes with a double tube structure, and liquefied gas flows in from one end of the inner tube, and the vaporized gas is reversed at the open end of the inner tube opposite the closed end of the outer tube. The liquefied gas can be guided out by moving the annular passage between the outer tube and the inner tube, or the liquefied gas can be introduced from one end of the inner tube, and the liquefied gas can be introduced into the outer tube through a small hole provided on the outer periphery of the other closed end of the inner tube. It has a structure that allows gas-liquid mixing and allows vaporized gas to pass through an annular passage between the outer tube and the inner tube to be guided out, which reduces the amount of seawater that is unavoidable with conventional devices. This invention was completed after discovering that it is possible to obtain a vaporizer that can reduce the amount of water pump used, prevent flow rate and calorie hunting, and stabilize the flow of LNG and NG.

In this invention, the double tube structure is such that LNG is allowed to flow in from one end of the inner tube, and the LNG and NG are mixed into the outer tube through a small hole provided on the outer periphery of the other closed end, or by inversion from the open end. If NG can be extracted by passing through the annular passage between the inner tubes,
Any configuration can be adopted, such as the upper end of the inner tube protruding from the outer tube, or the NG being led out from the upper end of the outer tube provided at a higher position than the upper end of the inner tube.

Moreover, a finned tube with star fins protruding from the outer circumferential surface can be used as the outer tube. Furthermore, it is also possible to increase the heat transfer area by providing notches or irregularities on the inner surfaces of both the inner tube and the outer tube.

In this invention, a spiral heat transfer promoter is inserted into the tube, which generates stirring and turbulence to promote heat transfer, and the twist pitch and shape are adjusted to the desired heat exchange efficiency. It is recommended to select the appropriate one depending on the situation.

In this invention, when the LNGN input is provided at the end of the double pipe, the header tank is provided with LNG on the NG outlet side.
It may be at any position as long as it is N sunset.

In addition, when installing the NG outlet header tank at the upper end of the outer pipe, in order to sufficiently heat the NG cooled by the LNG immediately after inflow,
Although it is placed at a required distance from the G outlet, it may be placed at any position above the center of the heat exchange panel.

In this invention, the water sprinkling trough may have any configuration as long as it can spray seawater from the upper part of the heat exchange panel to the outer circumferential surface of the outer pipe, but at least it does not spray water to the LNG-filled header tank. It is recommended to arrange the header tank according to the position of each header tank.

In this invention, when the NG output header tank is installed at the upper end of the outer tube, it is necessary to cover the upper outer periphery of the inner tube with a heat insulating material so that the NG to be discharged is not cooled by the LNG immediately after inflow. Using a known heat insulating material such as stainless steel, the coating position, range, amount, etc. may be appropriately selected depending on the conditions such as the above-mentioned double pipe structure, inlet header tank position, and NG outlet position.

Based on the Drawings (Disclosure of the Invention) FIGS. 1 to 3 are longitudinal sectional views showing the structure of a double-tube open rack type vaporizer according to the present invention.

Figures 4 and 5 are graphs showing the temperatures of seawater, LNG, and NG depending on the height position of the heat exchange panel.

Configuration 1 The double-tube open rack type vaporizer according to the present invention shown in FIG. An LNG input Romulo header tank and an NG output header tank are installed on the top of the tank.

Each heat exchange tube has an inner tube (11) inserted into an outer tube (10) having a required length and inner diameter and whose lower end is closed.
) has its lower end open on the inner bottom of the outer tube (10),
In addition, the upper end of the inner pipe (11) is connected to the LNG-filled Rohesogoo tank (
12) to allow LNG to be introduced and flowed down, and the header tank (12) closes the upper end of the outer pipe (10).

A ribbon-shaped heat transfer accelerator (30) with the required twist is inserted into the inner tube (1).
A spiral heat transfer accelerator (31) with a required pitch is inserted into the annular passage between the outer tube (10) and the outer tube (10).

The NG bidding header tank 14) is an NG bidding header tank 14) connected to the outer pipe (10) below the LNG input Robero Muro header tank 2.
It is arranged via an outlet pipe (13).

In addition, on the outer surface of each outer tube (10) constituting the heat exchange panel, LN is provided below the NG outlet tube (13) side and on the opposite side.
Overflow water flows down from the water troughs (15 x 16) placed opposite to each other below the G-in Robero Muro header tank 2.

Furthermore, the inner pipe (11) has a required length on the outer peripheral surface from the connection part of the LNG-filled Robero Muro header tank 2 to the lower part of the water sprinkling trough (15) on the NG outlet pipe (13) side.
A heat insulating material (17) is applied.

Effects and Effects The supplied LNG flows downward through the inner pipe (11) from the inlet tank (12) and is heated by NG, which will be described later, from the lower end of the opening of the inner pipe (11) until it is turned over at the inner bottom of the outer pipe (10). and partially vaporizes.

The partially vaporized LNG is further heated while rising through the annular passage between the outer tube (10) and the inner tube (11),
) is led out as NG at room temperature to the NG bidding header tank 14) via the NG exit pipe (13) connected above.

In the open rack type vaporizer according to the present invention, the heat exchange tube is constructed with a double tube, so that the heat medium seawater and the cryogenic LNG do not directly exchange heat, but heat is transferred through the NG in the annular passage. Because of the replacement, the amount of swimwear on the surface of the outer tube (1o) is reduced, and the vaporization device can be downsized by increasing the heat transfer area.

Therefore, by reducing the number of swimsuits, it is possible to reduce the amount of seawater to be supplied, and the power consumption of the seawater pump can be significantly reduced.

In addition, by positioning the LNG-filled Robero Muro header tank 2, which is supplied with cryogenic LNG, above the trough (15x16), the LNG-filled Robero Muro header tank 2
Heat input from seawater can be prevented, and flow rate hunting and calorie hunting to each heat exchange tube can be prevented.

By inserting heat transfer accelerators (30x31) into the inner tube (11) and outer tube (10), it is possible to generate agitation and turbulence in the fluid passing through the tubes. L of
The heat transfer coefficient between the NG and the NG in the outer tube (10) is greatly improved.
By varying the performance of 1) by, for example, changing the twist pitch, it is possible to set the NG inside the outer tube (10) to a required temperature and prevent swimsuits from getting on the surface of the outer tube (10). can.

In addition, by configuring the heat exchange tube as a double tube, the inner tube (
11) NG can be supplied into the outer tube (10) from the lower end to create a U-shaped flow that rises inside the tube and exits from the upper end to the outside, increasing the pressure loss inside the tube and stabilizing the gas flow. .

Further, the open rack type vaporizer according to the present invention has L
The required upper part of the inner pipe (11) to which cryogenic LNG is supplied from the NGN0 tongue header tank 2) is surrounded by a heat insulating material (17) to prevent a drop in NG temperature near the NG outlet located close to it. are doing.

To explain in detail, in the open rack type vaporizer having the configuration shown in FIG.
), the temperature of the NG decreases near the NG outlet pipe (13), as shown in Figure 4, but when the insulation material (17) is installed, the temperature of the NG decreases to the same level as the seawater, as shown in Figure 5. The temperature is raised to near the temperature.

Configuration 2 The double-tube open rack type vaporizer according to the present invention shown in FIG. An LNG input Romulo header tank and an NG output Romulo header tank are installed at the top of the tank.

In each heat exchange tube, an inner tube (21) shorter than the outer tube (20) is inserted into an outer tube (20) having a required length and inner diameter and whose lower end is closed. The lower closed end of the inner pipe (21) is visible at the lower end of the inner pipe (21), and the lower part of the inner pipe (21) is provided with small holes (21a) of the required inner diameter by optimally selecting the installation range, spacing, and number. The upper end of the inner pipe (21) is located below the upper end of the outer pipe (20) by a required distance, and the upper end of the outer pipe (20) is connected to the NG outlet header tank (24) to enable NG to be taken out. ing.

A ribbon-shaped heat transfer accelerator (30) with a required twist is inserted into the inner tube (21).
A spiral heat transfer accelerator (31) with a required pitch is inserted into the annular passage between the outer tube (21) and the outer tube (20).

An outer pipe (20
) through an LNG inlet pipe (23) connected to the upper part of the inner pipe (21).

Further, the LNG inlet pipe (23) and the LNG-filled header tank 2 are entirely coated with a heat insulating material (28).

The outer surface of each outer tube (2o) constituting the heat exchange panel is coated with N.
Overflow water from the water troughs (25x26) placed oppositely below the G output header tank (24) flows down, and the water troughs (2
7) Overflow water flows down.

Furthermore, on the insulation material (28) of the LNG artificial pipe (23), there is a water trough (
A scattering prevention plate (29) is provided around the LNG-containing Robero Muro header tank 2 so that overflow water from the tank 26) is not sprayed onto the LNG-containing Robero Muro header tank 2.

The supplied LNG is introduced into the inner pipe (21) from the inlet header tank (22) via the LNG inlet pipe (23), flows downward inside the pipe, and is connected to the outer pipe (2o) and the inner pipe. The LNG in the inner tube (21) and the outer tube (2o NG in ) is a small hole (
21a) and the heat transfer promoters (30) and (31) arranged inside and outside the inner tube (11), heat can be exchanged efficiently, and for example, the heat exchange tube can be made shorter and smaller.

The obtained low-temperature NG is further heated while moving up the annular passage between the outer tube (20) and the inner tube (21), and
It passes the upper end of the outer tube (20) and further rises inside the outer tube (20).
20) NG outlet header tank (24) connected to the top end
It is derived as NG at room temperature.

Further, the open rack type vaporizer according to the present invention has L
An NG outlet header tank (24) is installed at the upper end of the inner pipe (21) at a required distance from the upper end of the inner pipe (21) to which cryogenic LNG is supplied from the NG inflow header tank (22). This structure does not exchange heat even indirectly with extremely low-temperature LNG, thereby preventing a drop in NG temperature.

[Dry Liao] The double pipe open rack type vaporizer according to the present invention shown in FIG. 1 is constructed by turning the heat exchange panel similar to the structure shown in FIG. In addition to the NG output header tank (14) located at the bottom of the panel, there is also a header tank (14) arranged in parallel, and there is no header tank near the water trough (15 x 16) located at the top of the panel.

The supplied LNG ascends from the inlet header tank (12) through the inner pipe (11) containing the heat transfer promoter (30),
The LNG in the inner tube (11) and the NG in the outer tube (10) mix directly through the small hole (Ila) provided at the upper part of the inner tube (11), increasing efficiency. Good heat exchange can be achieved, and the same effects as in the configuration shown in FIG. 1 can be obtained.

[Brief explanation of the drawing]

FIGS. 1 to 3 are longitudinal sectional views showing the structure of a double pipe open rack type vaporizer according to the present invention. Figures 4 and 5 are graphs showing the temperatures of seawater, LNG, and NG depending on the height position of the heat exchange panel. FIG. 6 is a perspective explanatory view of a single-tube open rack type vaporizer. 10.20...Outer tube, 11.21...Inner tube, 12.
22...LNG filled Romulo header tank 33...
・NG outlet pipe, 14.24...NG outlet Rohesogoo tank, 15.16
,25,26.27...Water trough,17.18,2
7, 28...Insulating material, 21a...Small hole, 29...
Scattering prevention plate, 30, 31... heat transfer promoter.

Claims (1)

[Claims] 1. A heat exchange panel is formed by connecting a large number of heat exchange tubes with a double pipe structure, and a liquefied gas inlet header tank and a vaporized gas outlet header tank are arranged at the upper or lower part of the heat exchange panel, A water sprinkling trough is installed at the top of the panel to allow liquefied gas to flow in from one end of the inner tube, and to invert the vaporized gas at the open end of the inner tube opposite the closed end of the outer tube between the outer tube and the inner tube. What is claimed is: 1. A double-tube open rack type vaporizer, comprising a structure in which the heat is drawn out by moving an annular passage, and characterized in that a heat transfer accelerator is inserted into either the inner tube or the annular passage. 2. A heat exchange panel is formed by connecting a large number of heat exchange tubes with a double-pipe structure, and a liquefied gas inlet header tank and a vaporized gas outlet header tank are placed at the top or bottom of the heat exchange panel, and a water spray tank is installed at the top of the panel. A trough is installed to allow liquefied gas to flow in from one end of the inner tube, and to mix gas and liquid inside the outer tube through a small hole provided on the outer periphery of the other closed end of the inner tube. 1. A double-tube open rack type vaporizer, characterized in that a heat transfer accelerator is inserted into either the inner tube or the annular passage.