JPH03286990A - Double pipe type open rack gasifying apparatus - Google Patents

Abstract

PURPOSE:To prevent the hunching of a flow rate to reduce adfreezing and the amount of seawater and to stabilize the flow of gas by a method wherein liquefied gas is allowed to flow in an inner pipe from one end thereof and introduced into an outer pipe from the small holes provided to the outer periphery of the inner pipe on the other closed end side thereof to be subjected to gas-liquid mixing within the outer pipe while the formed gas is passed through the annular passage between the outer and inner pipes to be led out. CONSTITUTION:Supplied LNG flows downwardly through an inner pipe 11 from an inlet header tank 12 and is heated by NG rising through the annular passage between outer and inner pipes 10, 11 to be gasified but LNG in the inner pipe 11 is discharged from the small holes 11a provided on the lower part of the inner pipe 11 to be directly mixed with NG in the outer pipe 10 to be efficiently subjected to the heat exchange with NG and, for example, a heat exchange pipe can be made short and small-size. The obtained low temp. NG is further heated during the rising through the annular passage between the outer and inner pipes 10, 11 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. The adfreezed amount on the surface of the outer pipe 10 due to the temp. drop of NG is suppressed.

Description

[Detailed Description of the Invention] Field of Application The present 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, and for example, the upper end The structure is such that liquefied natural gas is supplied from the lower part to the inner pipe, and vaporized gas is led out in a U-shaped flow from the small hole on the outer periphery of the lower part to the upper part of the outer pipe through the passage between the outer pipe and the inner pipe. This invention relates to a double-tube open rack type vaporizer that prevents the use of swimsuits, reduces the amount of seawater, and stabilizes the flow of gas.

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 oven 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 oven 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 explain in detail, if there is a bias in the flow rate of water spray supplied to each heat exchange tube of the heat exchange panel (1), an imbalance occurs in the height of the swimsuit on the outer surface of the tube. As the LNG flow rate increases, the amount of swimsuit 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 oven 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 how to use the passage between the ceramic tube and the outer tube with consideration to heat transfer efficiency, has not been proposed.

Purpose of the Invention The present invention has a double-tube structure for the heat exchange tube and a lower header tank in order to reduce the problem of water deposits on the surface of the heat exchange panel, which was a problem in conventional single-tube oven rack type vaporizers. The purpose of the present invention is to provide a double-pipe oven rack type vaporizer that prevents flow rate hunting, reduces swimwear, reduces the amount of seawater, 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. It has a configuration in which a watering trough is arranged at the top of the panel, allowing liquefied gas to flow in from one end of the inner tube, and allowing gas-liquid mixing in the outer tube through a small hole provided on the outer periphery of the other closed end of the inner tube. This is a double-pipe open rack type vaporizer characterized in that vaporized gas is led out through an annular passage between an outer tube and an inner tube.

Various configurations are possible for the double-tube oven rack type vaporizer according to the present invention, but to give an example in detail, a heat exchange panel is formed by connecting a large number of heat exchange tubes with a double-tube structure, and the panel A water sprinkler trough is installed at the top to enable heating, and liquefied gas is introduced into the inner pipe from an inlet header tank installed at the upper or lower end of the heat exchange pipe, and the pipe is blocked at the opposite position from the inlet header tank. Gas and liquid can be mixed inside the outer tube through small holes provided on the outer circumference of the inner tube on the end side, and the fluid moving upward or downward through the annular passage between the outer tube and the inner tube, the water sprinkled on the outer surface of the outer tube, and the liquefied gas inside the inner tube. The configuration allows for heat exchange, and allows the vaporized gas that has been vaporized and heated to be led out from the outlet header tank, which is connected to the outer pipe on the inlet header tank side.

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. The configuration is such that vaporized gas is led out from an outlet header tank connected to the end of the outer tube.

Structure of the Invention The present invention provides an L
As a result of various studies aimed at creating an oven rack-type vaporizer with a double-tube structure that reduces the amount of NG-containing Romulo header tank side swimsuits, we decided to form a heat exchange panel by forming a heat exchange panel by connecting a large number of double-tube structure heat exchange tubes to reduce liquefaction. Gas is allowed to flow in from one end of the inner tube, and gas and 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 the vaporized gas is passed through a circular passage between the outer tube and the inner tube. During the passage and extraction, seawater → outer pipe → NG → inner pipe →
With a configuration that inputs heat with LNG, it is possible to reduce the amount of seawater by reducing the amount of water that is unavoidable with conventional equipment, reduce the amount of pump used, prevent flow rate and calorie hunting, and reduce the flow of LNG and NG. They discovered that a stable vaporization device could be obtained and completed this invention.

In this invention, the double pipe structure allows LNG to flow in from one end of the inner pipe, and through a small hole provided on the outer periphery of the other closed end.
If LNG and NG can be mixed and passed through the annular passage between the outer tube and the inner tube to lead out NG, the upper end of the inner tube will protrude from the outer tube, and the NG can be extracted from the upper end of the outer tube, which is provided at a higher position than the upper end of the inner tube.
Any configuration can be adopted, such as deriving .

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.

For small holes to be provided on the outer periphery of the closed end of the inner tube, the installation range, hole arrangement, size, etc. should be selected appropriately, taking into consideration various conditions such as the inner and outer tube dimensions, heat exchange efficiency, etc. By selecting the position, size, and number of small holes, the increase in NG temperature within the outer tube can be set arbitrarily, and the amount of swimwear generated on the outer surface of the outer tube due to a decrease in NG temperature can be suppressed.

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 NGG outlet side.
It may be at any position as long as it is N sunset.

In addition, when providing an NG outlet port at the upper end of the outer pipe of the header tank, in order to sufficiently heat the NG cooled by the LNG immediately after inflow, the N
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 tube, but at least it can be configured so that the water from the LNG-containing Romuro Muro header tank does not flow. It is recommended to arrange the header tank according to the position of each header tank.

In this invention, it is desirable to perform heat insulation treatment on the internal pipe connection pipe of the LNG-containing header tank, and by using a known heat insulating material such as Bakelite or stainless steel, The coating position, range, amount, etc. may be appropriately selected depending on conditions such as the exit 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.

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 panel.

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 closed lower end facing the inner bottom of the outer tube (10),
The lower part of the inner pipe (11) is provided with small holes (lla) of the required inner diameter, with the installation range, spacing, and number optimally selected.
It is connected to allow LNG to be introduced and flowed down, and the header tank (12) closes the upper end of the outer pipe (10).

The NG outflow header tank (14) is an NG outflow header tank (14) connected to the outer pipe (lO) below the LNG inflow 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-filled Romulo header tank 2.

Furthermore, a heat insulating material (17) is adhered to the outer peripheral surface of the LNG-filled header tank 2.

Effect: The supplied LNG flows downward from the inlet header tank (12) through the inner pipe (11), and flows through the outer pipe (lO) and the inner pipe (lO).
1) The LNG in the inner tube (11) and the outer tube (10) are heated and vaporized by the NG rising through the annular passage between the inner tube (11) and the outer tube (10). The NG inside the tube mixes directly with the NG through the small holes (lla), allowing efficient heat exchange, and, for example, the heat exchange tube can be made shorter and smaller.

The obtained low-temperature NG is further heated while rising through the annular passage between the outer tube (10) and the inner tube (11).
) is led out as room temperature NG to the NG output header tank (14) via the NG outlet pipe (13) connected above.

By selecting the position, size, and number of the small holes (lla), it is possible to arbitrarily set the increase in the NG temperature inside the outer tube (10). The amount of swimwear can be suppressed, and thermal stress caused by unbalanced icing can be prevented.

Specifically, as shown in FIG. 3, when the temperature at the turning point at the lower end of the heat exchange panel is low, the tube wall temperature of the outer tube (10) becomes lower than the freezing point temperature of seawater, and the outer tube (10) constituting the panel 10) The seawater bathing area increases, but the aforementioned inner pipe (
A small hole is provided on the outer periphery of the outlet side of the tube (11), and an L
When NG and NG are mixed in gas and liquid to efficiently exchange heat, the temperature at the folding point at the lower end of the panel can be increased, as shown in Figure 4, and the temperature of the wall of the outer tube (10) can be brought to the freezing point temperature of seawater. By reducing the number of swimsuits, it is possible to reduce the amount of seawater to be supplied, and the power consumption of seawater pumps can be significantly reduced.

In addition, by positioning it above the trough (15 x 16) of the LNG-filled Romuro-Muro header tank 2 to which cryogenic LNG is supplied, the LNG-filled Romura-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.

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 NG-filled Romulo Header Tank 2 is surrounded with a heat insulating material (17) to prevent the NG temperature from decreasing near the NG outlet located close to it. It is prevented.

To be more specific, by providing a heat insulating material (17) at the required upper part of the inner tube (11), the temperature of NG can be reduced as shown in Fig. 3.
The temperature of NG is raised to near seawater temperature without decreasing near the G outlet pipe (13).

The double-tube oven rack type vaporizer according to the present invention shown in FIG. At the top of the panel is an LNG input Robero header tank and an NG source header 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 (2) is visible, and small holes (21a) with the required inner diameter are provided at the bottom of the inner pipe (21) with the installation range, spacing, and number optimally selected. , 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 header tank 24) from which the NG is sourced, so that the NG can be taken out. ing.

The LNGN0 Muro header tank 2) has 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 Romuro Vero header tank 2 are entirely coated with a heat insulating material (28).

The outer surface of each outer tube (20) constituting the heat exchange panel is coated with N.
Overflow water from the water trough (25 x 26) placed oppositely below the G outlet header tank 24) flows down, and the water trough (2
7) Overflow water flows down.

Furthermore, on the insulation material (28) of the LNG inlet pipe (23), there is a water trough (
A scattering prevention plate (29) is provided around the tank to prevent water from spilling from the tank 26) from being sprayed onto the LNG-containing Romuro Vero header tank 2.

The LNG supplied by the Kari hot ball is introduced from the inlet header tank (22) through the LNG inlet pipe (23) into the inner pipe (21), flows downward inside the pipe, and is connected to the outer pipe (20) and the inner pipe. The LNG in the inner tube (21) and the outer tube (20 NG in ) is a small hole (
21a), heat exchange can be performed efficiently, and, for example, heat exchange tubes can be shortened and miniaturized.

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 output header tank connected to the upper end 24)
It is derived as NG at room temperature.

Further, the oven rack type vaporizer according to the present invention has L
An NG source header tank 24) is installed at the upper end of the inner pipe (21) to which extremely low-temperature LNG is supplied from the NG-filled Romulo header tank 2. This structure does not exchange heat even indirectly with extremely low-temperature LNG, thereby preventing a drop in NG temperature.

To explain in detail, as shown in Fig. 4, the temperature of NG is
1) The temperature rises to near the seawater temperature without decreasing near the upper end.

Configuration 3 The double tube oven rack type vaporizer according to the present invention shown in FIG. 1 is constructed by turning the heat exchange panels similar to those shown in FIG. A header tank 14) located at the lower end is also arranged in parallel, and there is no header tank at all near the watering trough (15x16) located at the top of the panel.

The supplied LNG rises up the inner pipe (11) from the inlet header tank (12) and passes through the small hole (lla) provided at the top of the inner pipe (11) to the LNG in the inner pipe (11) and the outside. tube(
10) is directly mixed with the NG in the small hole (lla), allowing efficient heat exchange, and the same effect as the configuration shown in FIG. 1 can be obtained.

[Brief explanation of the drawing]

1 to 3 are longitudinal sectional views showing the structure of a double tube oven 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, lla
, 21a・"Small hole, 12.22...LNG inlet Romuro Muro header tank 33...NG outlet pipe, 14.24・
・NG output Rohetsuder tank, 15.16, 25, 26
．． 27...Water trough, 17,27,28...Insulating material, 29...Scatter prevention plate.

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 on the upper part of the heat exchange panel, and each header It consists of a watering trough installed at the bottom of the tank, allowing the liquefied gas to flow downward from the top of the inner pipe, and flowing into the outer pipe through small holes provided on the outer periphery of the lower part of the inner pipe, which has a closed lower end or a lower end with a small hole. A double-pipe open rack type vaporizer that allows gas-liquid mixing in the lower part and that vaporized gas is led out by ascending an annular passage between an outer tube and an inner tube. 2 A heat exchange panel is formed by connecting a large number of heat exchange tubes with a double pipe structure, a liquefied gas inlet header tank and a vaporized gas outlet header tank are arranged at the bottom of the heat exchange panel, and a watering trough is installed at the top of the panel. The liquefied gas rises from the lower part of the inner tube, and the small hole provided on the upper outer periphery of the inner tube, which has a closed upper end or an upper end with a small hole, allows gas-liquid mixing in the upper part of the outer tube. A double-pipe open rack type vaporizer characterized in that vaporized gas is led out by descending an annular passage between an outer tube and an inner tube.