JPH03239897A - Vaporizer device of low-temperature liquefied gas - Google Patents

Abstract

PURPOSE:To prevent the icing of a heat source even if the temperature of a liquid is low and simplify structure by forming a passage communicating the upper part of a space between 3rd and 4th pipe plates with a space between 2nd and 3rd pipe plates, and providing a low-temperature liquefied gas inlet in the lower part of the space between the 3rd and 4th pipe plates and a gas outlet in the lower part of the space between 1st and 4th pipe plates. CONSTITUTION:First and 2nd pipe plates 66, 68 forming an inlet side water chamber 67 in the lower part of a body 65 and an outlet side water chamber 69 in the upper part, 3rd and 4th pipe plates 72, 73 disposed vertically between the 1st and 2nd pipe plates 66, 68, an inner heat conductive pipe 77 extending between the 1st and 2nd pipe plates 66, 68 and communicating the inlet and outlet side water chambers 67, 69 to each other, and an outer heat conductive pipe 79 extending between the 3rd and 4th pipe plates 72, 73 and enclosing the inner heat conductive pipe 77 are provided. A passage 80 communicating the upper part of a space between the 3rd and 4th pipe plates 72, 73 to a space between the 2nd and 3rd pipe plates 68, 72 and a low- temperature liquefied gas inlet in the lower part of a space between the 3rd and 4th pipe plates 72, 73 are provided, and a gas outlet is provided in the lower part between the 1st and 4th pipe plates 66, 73.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for vaporizing low temperature liquefied gas such as liquefied natural gas and a novel cooling apparatus for cooling the vaporizer during standby.

Prior Art A first prior art is shown in FIG. In this prior art, liquefied natural gas at -155° C. is supplied from an inlet 1 to a heat exchanger tube 3 of an intermediate heat medium type vaporizer 2 and is vaporized. Inside this vaporizer 2, there is a liquid phase 4 such as chlorofluorocarbon or propane.
and a gas phase 5 are formed. The liquefied natural gas at -50°C vaporized in the vaporizer 2 is supplied to the input lower of the warmer 6, passes through the warmer 6, and exits from the outlet 8.
Vaporized liquefied natural gas at 0°C is obtained. Seawater as a heat source passes through the heat exchanger tube 10 of the warmer 6 from the inlet 9, further passes through the heat exchanger tube 11 provided in the liquid phase 4 of the vaporizer 2, and is discharged from the outlet 12.

In the prior art shown in FIG. 6, it is easy to confirm the flow rate of seawater, the thickness of ice on the inner surface of the heat transfer tube 10 is small, and the amount of seawater used per ton of liquefied natural gas is small. There is an advantage.

On the other hand, it is necessary to increase the number of heat transfer tubes 10 of the warmer 6, increase the body diameter of the warmer 6, and thicken the tube plate, resulting in an increase in size and construction cost. By simplifying the structure of the vaporizer 2 and lowering the temperature of the vaporized liquefied natural gas led from the vaporizer 2 to the input lower of the warmer 6, the total cost of the vaporizer 2 and the warmer 6 can be reduced. Although it is desired to reduce the temperature, if the temperature of the lower part is made too low, ice will form inside the heat transfer tubes 10, and the heat transfer efficiency will decrease, so there is a limit to the cost reduction.

A second prior art is shown in FIG. 7, in which the vaporizer 2 corresponds to the vaporizer 2 shown in FIG. The gas is vaporized through the heat exchanger tube 3 of the intermediate heat medium type vaporizer 2, for example -
Vaporized liquefied natural gas at 40° C. is supplied from the inlet 14 into the warmer 15, and vaporized liquefied natural gas at 0° C. is obtained from the outlet 16. In the vaporizer 2, seawater as a heat source is introduced into the heat transfer tube 11 from an inlet 17, and the seawater is discharged from an outlet 18. Further, seawater is supplied to the warmer 15 from an inlet 19, passes through a heat transfer tube 20, and is discharged from an outlet 21. Seawater is supplied to the vaporizer 2 and the warmer 15 at a flow rate ratio of, for example, 2:1.

The prior art shown in FIG. 7 has the advantage that the body diameters of the vaporizer 2 and the warmer 15 are small, and the pressure loss of the seawater is small. If the temperature of the vaporized liquefied natural gas at the inlet 14 is lower than 140° C., ice formation in the heat exchanger tubes 20 near the seawater outlet 21 indicated by the reference numeral 22 of the warmer 15 increases, and, for example, ice is discharged from the outlet 21. The seawater temperature is 2
℃, there is a problem that ice adheres to a thickness of 2 mm or more inside the heat exchanger tube 20, so it is necessary to increase the outlet seawater temperature in order to improve heat exchange efficiency.
If this is done, there is a problem that the amount of seawater used will increase.

In the prior art shown in FIGS. 6 and 7, the intermediate heat medium is stored in the intermediate heat medium type vaporizer 2, and therefore the intermediate heat medium must be taken in and out during open inspection, which is troublesome. , maintenance costs will also increase.

Yet another prior art technique that does not use such an intermediate heat transfer medium is shown in FIG. A heat transfer tube 24 is provided inside the shell 23 that extends vertically, and seawater flows from the tube 25 to the inlet side water chamber 26.
and flows into the outlet side water chamber 27 through the heat exchanger tube 24 . The other shell 28 is also provided with a heat exchanger tube 29, and from the seawater conduit 30 to the inlet side water chamber 31 and the heat exchanger tube 29.
The water flows to the outlet side water chamber 32 through the. The liquefied natural gas to be vaporized is introduced from the pipe 33 into the space 34 between the inner circumferential surface of the shell 23 and the outer circumferential surface of the heat transfer tube 24, and then from the pipe 35 into the inner circumference of the other shell 28. The vaporized liquefied natural gas is guided into the space 36 between the surface and the heat exchanger tube 29, and is led out from the pipe line 37.

In the prior art shown in FIG. 8, the conduit 25.
When the temperature of the seawater supplied to the heat exchanger tubes 24 becomes low,
．． 29's inner wall becomes thicker, and the pressure loss of seawater increases. In addition, in this prior art, since the liquefied natural gas comes into contact with the inner surface of the shell 23.28, a telescopic pipe is provided in the shell 23.28, or seawater is flowed on the outer circumferential surface of the shell 23.28.
It is necessary to take measures against shrinkage due to the temperature difference between the shell 23.28 and the heat exchanger tubes 24.29.

Yet another prior art is shown in FIG.
A cross section taken along the section line XX in the figure is shown in FIG. In this prior art, seawater is supplied from a pipe 41 to a water sprinkler 43 in a pipe 42, and the heat transfer panel 4
It flows down onto the outer surface of 4. The liquefied natural gas passes through the header 46 from the pipe 45, ascends the heat transfer panel 44, and reaches the header 4.
The liquefied natural gas vaporized from 7 is led out through a pipe 48.

In the prior art shown in FIGS. 9 and 10, when the temperature of the seawater supplied through the pipe 41 rises and the seawater flow rate is throttled accordingly, the seawater flows from the sprinkler 43 to the panel. There is a problem in that it is not possible to form a water film with a uniform thickness over the entire surface of 44. Also, in the prior art shown in FIGS. 6 and 7, if the seawater flow rate is extremely reduced, seawater will no longer flow into the upper heat transfer tube of the heat transfer tubes 10, 11, 20.

Furthermore, in the prior art shown in FIGS. 9 and 10, in order to increase the capacity and pressure of equipment, the number of heat transfer panels 44 is increased, and the flow rate of liquefied natural gas to each header 4647 is uniform. Measures need to be taken for allocation.

Furthermore, in the prior art shown in FIGS. 9 and 10, in the standby state, the sprinkling of seawater by the water sprinkler 43 is stopped, and liquefied natural gas is supplied from the pipe 45 at a small flow rate, so that the pipes 45, 48 , headers 46, 47, and heat transfer panels 44 must be cooled. Therefore, the header 4 at the bottom
6, concentration of high-boiling components of liquefied natural gas occurs,
At the time of restarting, there is a problem in that the components of the vaporized liquefied natural gas obtained from the pipe line 48 change, and the calorific value thereof fluctuates.

In addition, in the prior art shown in FIGS. 6 and 7 described above, it is necessary to flow a small amount of liquefied natural gas to cool the piping system, but due to the structure, the liquefied natural gas compartment is kept cool. This has the advantage that concentration of the high boiling point components of liquefied natural gas is unlikely to occur, and therefore there is almost no problem of fluctuations in the calorific value of vaporized liquefied natural gas obtained at restarting. Approximately 1 to 20% of the water needs to be kept flowing at all times. Furthermore, in the prior art shown in FIGS. 6 and 7, when the heat transfer tubes are left in a standby state for a long period of time, seawater stagnates inside the heat exchanger tubes or inside the partition chambers, causing marine organisms to grow attached to the tubes or to damage the tube sheets. Heat exchanger tubes 10, 11
．． There is a risk of corrosion occurring in the welded parts of the heat exchanger tubes 10, 11, 20, and in particular, foreign matter clogging or adhesion of marine life to the inner surface of the heat exchanger tubes can cause ice formation and blockage of the heat exchanger tubes 10, 11 and 20, so in order to prevent this, It is necessary to periodically flush a certain amount of seawater and check for the presence of adhesion and the health of the welded parts during the breeding season of marine organisms.

Further, other prior art is, for example, Japanese Patent Application Laid-open No. 56-30585.
and is shown in FIG. An inlet water chamber 52 formed at one end of the horizontally extending body 51
This water is discharged from the outlet side water chamber 54 formed at the other end of the body 51 through the autobiographical heat tube 53, and at this time, liquid liquefied natural gas pumped from the body 55 is supplied. Vaporize. The liquefied natural gas from the inlet 55 is guided to the outlet space 57 through the outer periphery of the external heat exchanger tube 56 which forms a double tube together with the autobiographical heat tube 53, where the liquefied natural gas is
The gas from the outlet space 57 is discharged from the flow rate control valve 58 at about 5% of the liquefied natural scum.
degree is led to conduit 59. The vaporized liquefied natural gas in the outlet space 57 passes through the space between the autobiographical heat transfer tube 53 and the external heat exchanger tube 56, and from another outlet space 60 via the conduit 61 to the conduit 62 together with the gas in the aforementioned conduit 59. Supplied from. Both ends of the autobiographical heat tube 53 are fixed to tube plates 63 and 64 that partition the inlet-side water chamber 52 and the outlet-side water chamber 54, respectively.

Problems to be Solved by the Invention A new problem with the prior art shown in FIG. That temperature is too low. The temperature of the vaporized liquefied natural gas supplied from the pipe line 61 should preferably be around room temperature.

Also, in the prior art shown in FIG. 11, the shell 51 is cooled to a low temperature by liquid liquefied natural gas and contracts, whereas the autothermal tube 53 is expanded by the water flowing therein. Therefore, there is a possibility that thermal stress acts on the body 51 and the autobiographical heat tube 53, causing the autobiographical heat tube 5-3 to buckle.

Furthermore, this prior art has a problem in that a flow control valve 58 is required in the middle of the pipe line 59 to control the flow rate of the low-temperature vaporized liquefied natural gas.

An object of the present invention is to prevent problems such as icing from occurring even if the temperature of the liquid in the heat source is low, and to simplify the configuration.
Furthermore, it eliminates the need to flow low-temperature liquefied gas or heat source liquid in a standby state, is easy to maintain, can obtain low-temperature liquefied gas vaporized at or near room temperature, and can prevent damage due to thermal stress. It is an object of the present invention to provide an improved low-temperature liquefied gas vaporization device that can perform the following steps.

In a low-temperature liquefied gas vaporizer, when it is on standby, for example, when the temperature has risen to around room temperature, intense boiling occurs when the low-temperature liquefied gas of the liquid to be vaporized is newly supplied. To solve this problem, it is necessary to cool the vaporizer to a low temperature when it is on standby.

Another object of the present invention is to provide a novel cooling device for cooling a low-temperature liquefied gas vaporization device when it is in a standby state.

Means for Solving the Problems The present invention comprises: a vertically extending body; a first tube plate forming an inlet water chamber in the lower part of the body; and a second tube plate forming an outlet water chamber in the upper part of the body. , a third tube sheet disposed between the first tube sheet and the second tube sheet with an interval in the vertical direction.
and a fourth tube sheet; an autobiographical heat tube extending between the first and second tube sheets and communicating the inlet side water chamber and the outlet side water chamber; a third and a fourth outer heat exchanger tube surrounding the outer heat exchanger tube at intervals in the direction;
A flow path is formed that communicates the upper part of the space between the tube sheets with the space between the second and third tube sheets, and the lower part of the space between the third and fourth tube sheets is provided with an inlet for low-temperature liquefied gas. This is a low-temperature liquefied gas vaporization device, characterized in that the gas outlet is provided at the lower part of the space between the first and fourth tube sheets.

Furthermore, the present invention provides fifth and sixth tube sheets that are vertically spaced apart between the third and fourth tube sheets, and the fifth and sixth tube sheets are provided with grooves above and below the external heat transfer tubes. It is characterized by having a divided end.

Furthermore, the present invention is characterized in that an ultraviolet light source is provided in the water chamber on the outlet side.

The present invention also provides a structure that includes a vertically extending body, a first tube plate forming an inlet side water chamber in the upper part of the body, a second tube plate forming an outlet side water chamber in the lower part of the body, and a first tube plate. third, fourth, and fifth tube sheets arranged in order from top to bottom with vertical intervals between the second tube sheet; and an inlet side water chamber extending between the first and second tube sheets. a second external heat transfer tube extending between the third and fifth tube sheets and surrounding the autobiographical heat tube at intervals in the radial direction; a second external heat exchanger tube extending from the second tube sheet and having a vertical spacing between the second tube sheet and surrounding the autobiographical heat tube with a radial spacing therebetween; and the second and fifth
forming a passage communicating with the upper part of the space between the tube sheets, and providing an inlet for liquid low-temperature liquefied gas at the lower part of the space between the third and fourth tube sheets, and the space between the first and third tube sheets; This is a low-temperature liquefied gas vaporization device characterized by providing a gas outlet at the top of the liquefied gas.

Furthermore, in the present invention, a riser is interposed between a low-temperature liquefied gas vaporizer and a low-temperature liquefied gas supply source that pumps liquid low-temperature liquefied gas to the vaporizer, and a liquid level is maintained in the riser. A means for supplying the low temperature liquefied gas from the supply source to the riser pipe is provided so that the low temperature liquefied gas is supplied from the supply source to the standby pipe, thereby supplying the vaporized low temperature liquefied gas to the standby vaporizer to cool the vaporizer. This is a cooling device for a low-temperature liquefied gas vaporization device.

Function According to the present invention, water such as seawater is supplied from the inlet side water chamber provided at the lower part of the body extending vertically, and is discharged from the outlet side water chamber at the upper part of the body. The low temperature liquefied gas to be vaporized is supplied from the lower part of the space between the third and fourth tube sheets,
It is vaporized by contact with the external heat transfer tube, and the vaporized gas flows from the space between the second tube sheet and the third tube sheet, through the space between the autobiographical heat transfer tube and the external heat transfer tube, and then to the space between the first and fourth tube sheets. The vaporized low-temperature liquefied gas at about room temperature is guided into the space and further discharged from the lower part of the space between the first and fourth tube sheets.

Further, according to the present invention, by dividing the external heat transfer tube into upper and lower parts and attaching it to the fifth and sixth tube sheets that are vertically spaced between the third and fourth tube sheets, 6
Between the tube sheets, the temperature increases and expands due to the vaporized low-temperature liquefied gas, and therefore the thermal stress caused by the inner and outer heat exchanger tubes can be reduced.

Since the body extends vertically and the autobiographical heat tube extends vertically, by providing an ultraviolet light source in the water chamber on the outlet side, it is possible to prevent living things from adhering to the internal heat tube.

Furthermore, according to the present invention, the upper and lower ends of the vertically extending body are formed by an inlet side water chamber, an outlet side water chamber, and the first and second tube sheets, and a space is vertically spaced between the first and second tube sheets. A space is formed by the third, fourth, and fifth tube sheets arranged with a gap between them, and low-temperature liquefied gas of the liquid to be vaporized is supplied from the lower part of the space between the third and fourth tube sheets to raise the temperature. Next, the gas is supplied to the space between the second and fifth tube sheets to further raise the temperature, and the gas is supplied into the second and fifth spaces through the space between the autobiographical heat tube and the external heat transfer tube to raise the temperature. Then, through the space between the autobiographical heat transfer tube and the external heat exchanger tube between the third and fourth tube sheets, the gas is introduced into the space between the first and third tube sheets, where the temperature rises, and the vaporized gas at about room temperature is released outside. supply.

According to the present invention, the low-temperature liquefied gas vaporizer is supplied with low-temperature gas obtained by vaporizing the low-temperature liquefied gas stored in the riser, so that the vaporizer is always cooled to a low temperature. It is possible to prevent violent boiling from occurring when low-temperature liquefied gas to be vaporized is supplied.

Embodiment FIG. 1 is a longitudinal sectional view of another embodiment of the present invention. An inlet side water chamber 67 is formed by a first tube plate 66 in the lower part of the body 65, which has a generally right cylindrical shape and has a vertical axis extending vertically, and an outlet side water chamber 67 is formed in the upper part of the body 65 by a second tube plate 68. A side water chamber 69 is formed. A heat source liquid such as seawater is pumped into the inlet water chamber 67 from a pipe 70 through a strainer 71 for removing dust, and the seawater is discharged from the outlet water chamber 65 through a pipe 71.

Between the first tube sheet 66 and the second tube sheet 68, third and fourth tube sheets 72 and 73 are arranged vertically with an interval between them. Fifth and sixth tube sheets 74 and 75 are provided vertically spaced apart between the third and fourth tube sheets 72 and 73.

These tube sheets 6668, 72, 73, 74, 75 are airtightly fixed to the shell 65 by welding or the like.

A plurality of internal pressure heat tubes 77 are provided between the first and second tube plates 66 and 68, and the inlet side water chamber 68 and six outlet side water chambers are communicated through the internal pressure heat tubes 77. External heat transfer tubes 78.79 are provided between the third and fourth tube plates 72.73 and surround the internal pressure heat tubes 77 at intervals in the radial direction, and the external heat transfer tubes 78.79 are divided into upper and lower parts. 5th
and is airtightly fixed to the sixth tube plate 74,75. The upper part of the space between the third and fifth tube sheets 72, 74 is connected to the connecting pipe 80.
communicates with the space 82 between the second and third tube sheets. The upper part of the space 83 between the fourth and sixth tube sheets 73, 75 is communicated with the lower part of the space 81 by another connecting pipe 84. Low-temperature liquefied gas to be vaporized, for example, liquefied natural gas, is fed under pressure to the lower part of the space 83 through a pipe 85, and the vaporized liquefied natural gas at room temperature is transferred to the first
The lower part of the space 86 between the fourth tube sheets 66 and 73 is taken out to the outside via a conduit 87.

In spaces 8.1, 83.86, baffle plates 88, 89°90
is formed to form a zigzag path for liquid or gas to improve heat exchange efficiency.

FIG. 2 shows the temperature change of the liquefied natural gas to be vaporized in the embodiment shown in FIG. 1, and also shows the temperature change of the water used as a heat source. The liquefied natural gas to be vaporized is
The temperature is approximately -160° C. and enters the space 83 from the conduit 85. In this space 83, natural gas whose temperature has been raised to, for example, -25° C. is introduced into a space 91 between the external heat transfer tube 79 and the internal pressure heat tube 77, where it exchanges heat and is discharged from the pipe line 84. , vaporized liquefied natural gas at about −75° C. is introduced into space 81 . The natural gas flowing through the space 91 between the inner and outer heat exchanger tubes 77 and 79 has more heat absorbed by the liquefied natural gas than the heat received from the water passing through the internal pressure heat tube 77, and the temperature drops to about -40°C and is introduced into the space 86. I can escape. Although the temperature of the natural gas flowing through this space 91 suddenly drops in this way, it exchanges heat with the water flowing inside the inner heat transfer tube 77 in a counter flow, so
) vi The vicinity of the lower end will exchange heat with water such as seawater at about 4°C, and therefore, due to heat transfer characteristics, the tube wall temperature of the internal pressure heat tube 77 should be about 2°C or higher, which is the solidification temperature of seawater. Therefore, no ice builds up inside the internal heat transfer tube 77.

The low-temperature vaporized natural gas that has entered the space 81 comes into contact with the outer circumferential surface of the external heat transfer tube 78 and is gradually heated by the natural gas flowing through the space 92 between the internal pressure heat tube 77 and the external heat transfer tube 78 to a temperature of about -20 ℃ and enters the space 82 from the connecting pipe 80. The natural gas in the space 82 flows into the space 92 between the inner and outer heat exchanger tubes 77 and 78, and exchanges heat with low-temperature natural gas through the outer heat exchanger tube 78 and with seawater through the internal pressure heat tube 77, thus The temperature of the natural gas in the space 92 gradually decreases to around -25°C. Since the natural gas flowing in this space 92 exchanges heat with the seawater in a counterflow with the internal pressure heat tube 77, no ice builds up inside the inner heat tube 77.

Furthermore, since seawater is flowing into the internal heat transfer pipe 77, when the supply of seawater is cut off due to a power outage or other reason, the supply of liquefied natural gas from the pipe line 85 is cut off, and the water chamber 69 on the inlet side is Air flows in through the opening 93 for inspection, and the seawater in the inner heat transfer tube 77 is discharged through a drain valve 94 provided at the lower part of the inlet water chamber 67. In this way, the seawater inside the inner heat transfer tube 77 does not freeze.

In the space 81, a space 92 between the inner and outer heat exchanger tubes 77 and 78
Natural gas from the space 194 between the tube sheets 74, 75,
Space 91 between inner and outer heat exchanger tubes 77 and 79 in space 83
The natural gas is further heated in the space 86 and discharged from the pipe 87 at about room temperature. In the space 83.81, the shell 65 comes into contact with low-temperature liquid or gaseous liquefied natural gas and its temperature increases, but in the space 194 between the tube sheets 74.75, the shell 65 comes into contact with vaporized liquefied natural gas. , elongate,
In this way, there is no need for an expandable tube to relieve thermal stress in the shell 65, and in the present invention, the number of internal and external heat transfer tubes 77, 78 can be reduced, simplifying the configuration and reducing the size. This is possible, and maintenance is easy.

An ultraviolet light source 96 is provided at the upper part of the outlet side water chamber 69, thereby suppressing the breeding and adhesion of marine organisms and the like. Moreover, during standby when the operation is stopped, air flows in through the opening 93 and seawater in the inner heat tube 77 is discharged from the inlet side water chamber 67 through the drain valve 94, so that ultraviolet rays from the light source are absorbed into the inner heat tube. 77, thereby suppressing the adhesion and growth of marine organisms on the inner surface of the internal heat tube 77 in a moist state. A reflector may be attached to the light source 96 to further spread the ultraviolet rays. A strainer 71 may be provided in the water chamber 67 on the inlet side to prevent foreign matter such as dirt contained in the seawater from flowing into the seawater.

Instead of the ultraviolet light source 96, a means for emitting an electron beam or the like may be provided.

FIG. 3 is a longitudinal sectional view of another embodiment of the invention. This embodiment is similar to the embodiments of FIGS. 1 and 2 described above;
Corresponding parts are given the same reference numerals. It should be noted that in this embodiment, the aforementioned fifth and sixth tube plates 74, 75 are omitted, and the external heat exchanger tubes 78, 79 are not divided and extend in a straight tube shape. Such embodiments are also within the spirit of the invention.

FIG. 4 is a longitudinal sectional view of still another embodiment of the present invention. In this vaporizer 100, an inlet OS water chamber 102 is formed in the upper part of a vertically extending body 101 by a first tube plate 103, and an outlet side water chamber 104 is formed in the lower part of the body 101 in a second tube plate 103.
Formed by 05. First tube sheet 103 and second tube sheet 1
05, a third tube sheet 106, a fourth tube sheet 107, and a fifth tube sheet 108 are respectively arranged in order from top to bottom with an interval between the top and bottom, and are fixed to the shell 101 in an airtight manner.

The internal heat transfer tubes 109 extend to the first and second tube sheets 1o3105 tubes, and communicate the inlet side water chamber 102 and the outlet side water chamber 104.

A first external heat exchanger tube 110 is provided between the third and fourth tube sheets 106 and 107. The first external heat transfer tubes 110 surround the internal heat transfer tubes 109 at intervals in the radial direction. A second outer heat transfer tube 111 extending downward is attached to the fifth tube plate 108 so as to surround the inner heat transfer tube 109 at intervals in the radial direction. The lower end of this second external heat transfer tube 111- is connected to the second tube plate 105.
There is a distance d between them. Third and fourth tube sheets 10
The upper part of the space 112 between 6° 107 and the upper part of the space 113 between the second and fifth tube sheets 105 and 108 are the connecting pipe 1
14. third and fourth tube sheets 106,
An inlet is formed in the lower part of the space 112 between the pipes 107 and liquefied natural gas is supplied from the pipe line 116, and in the upper part of the space 117 between the first and third tube sheets 103 and 106, vaporized gas at about room temperature is formed. An outlet is formed through which liquefied natural gas is discharged via line 118.

Seawater serving as a heat source is pumped into the inlet water chamber 102 from a pipe 119, and seawater is discharged from the outlet water chamber 104 via a pipe 120.

The liquefied natural gas supplied from the pipe line 116 is
The external heat exchanger tube 110 is contacted at this point. Vaporized liquefied natural gas flows in the space 121 between the inner heat transfer tube 109 and the outer heat transfer tube 110, and heat is exchanged there. As a result, vaporized liquefied natural gas at about -180° C., for example, is introduced into the pipe line 114. The vaporized liquefied natural gas from the pipe line 114 is heated in the space 113, and the gaseous liquefied natural gas passes through the interval d to the inner heat transfer tube 109 and the outer heat transfer tube 11.
The gas rises from the space 122 between the fourth and fifth tube sheets 107 and 108, becomes a gas at about -15° C., and is introduced into the space 123 between the fourth and fifth tube sheets 107 and 108. In this space 123, the vaporized liquefied natural gas is heated to about -5°C, passes through the above-mentioned space 121, where the liquid liquefied natural gas absorbs heat, and the space 1
Gas within 21 enters space 107 at approximately -55°C. In the space 117, the temperature of the vaporized liquefied natural gas is raised, and the pipe 1
From 18, vaporized liquefied natural gas that has been heated to a room temperature of around 0° C. is discharged. In such a configuration, it is also possible to prevent seawater from icing in the internal heat tube 109, and to obtain vaporized liquefied natural gas at about room temperature as described above. An ultraviolet light source 124 is provided in the water chamber 102 on the entrance side to prevent breeding, adhesion, and growth of marine organisms.

FIG. 5 is a simplified cross-sectional view of another embodiment of the invention. Low-temperature liquefied gas vaporization equipment W shown in Figures 1 to 4
130 is supplied with liquid low-temperature liquefied natural gas from a supply source 131 through a pipe 132 under pressure. A part of this pipe line 132 is a riser pipe 133, and the on-off valve 1
Liquid liquefied natural gas is conducted via 34. Conduit 13
2 and its riser pipe 133, a side passage 135 is provided, and a valve 136 such as an on-off valve or a flow rate control valve is interposed therein. The riser 133 is provided with a liquid level detection means 137 for detecting a liquid level 138 of the liquid liquefied natural gas, and a control means 139 controls the opening and closing of the valve 136 in response to the output of the liquid level detection means 137. , this causes the liquid level 13
8 is maintained at a predetermined liquid level. When the vaporizer 130 is in a standby state after stopping operation, the riser tube 133
By storing liquefied natural gas inside the
The vaporized liquefied natural gas is guided to the waiting vaporizer 130, and the vaporizer 130 is cooled to a low temperature. Therefore, when the valve 134 is opened to supply liquid liquefied natural gas from the supply source 131 to the vaporizer 130 for vaporization, it is possible to prevent the liquid liquefied natural gas from boiling violently in the vaporizer fL30. Smooth operation can be resumed.

Effects of the Invention As described above, according to the present invention, it is possible to prevent ice from forming on the inner heat exchanger tube through which seawater is passed, and the structure is simplified and maintenance is easy, and the tube is downsized. ,moreover,
There is no need to flow low-temperature liquefied gas or heat source liquid in the standby state, and it is possible to obtain vaporized low-temperature liquefied gas at room temperature or close to room temperature, and it also avoids excessively large thermal stress on the shell and inner and outer heat exchanger tubes. never acts

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, FIG. 2 is a diagram showing the temperature distribution of the embodiment shown in FIG. 1, and FIG. 3 is a longitudinal cross-sectional view of another embodiment of the present invention. FIG. 4 is a longitudinal sectional view of yet another embodiment of the present invention, FIG. 5 is a sectional view of another embodiment of the invention, Section 6 is a sectional view of the prior art, and FIG. 7 is another prior art. FIG. 8 is a sectional view of another prior art, FIG. 9 is a sectional view of another prior art.
The figure is a cross-sectional view of still another prior art, Figure 0 is a cross-sectional view of the prior art as seen from the section line X-X shown in Figure 9, and Figure 11 is a cross-sectional view of still another prior art. It is.

Claims (5)

[Claims] (1) A body extending vertically, a first tube plate forming an inlet side water chamber in the lower part of the body, a second tube plate forming an outlet side water chamber in the upper part of the body, and a first tube plate and a second tube plate forming an outlet side water chamber in the upper part of the body. The third tube plate is arranged vertically and spaced apart from the tube sheet.
and a fourth tube sheet, an inner heat exchanger tube extending between the first and second tube sheets and communicating the inlet side water chamber and the outlet side water chamber, and an inner heat exchanger tube extending between the third and fourth tube sheets. and a third and fourth outer heat exchanger tube surrounding the outer heat exchanger tube at a radial interval.
A flow path is formed that communicates the upper part of the space between the tube sheets with the space between the second and third tube sheets, and the lower part of the space between the third and fourth tube sheets is provided with an inlet for liquid low-temperature liquefied gas. A low-temperature liquefied gas vaporization device, characterized in that the gas outlet is provided at a lower part of the space between the first and fourth tube sheets. (2) Fifth and sixth tube sheets are provided vertically spaced apart between the third and fourth tube sheets, and the ends of the external heat exchanger tubes are divided vertically into the fifth and sixth tube sheets. 2. A low-temperature liquefied gas vaporization device according to claim 1, further comprising: (3) The low-temperature liquefied gas vaporization device according to claim 1, characterized in that an ultraviolet light source is provided in the water chamber on the outlet side. (4) A body extending vertically, a first tube plate forming an inlet side water chamber in the upper part of the body, a second tube plate forming an outlet side water chamber in the lower part of the body, the first tube plate and the second tube plate forming an outlet side water chamber in the lower part of the body. third, fourth, and fifth tube sheets arranged in order from top to bottom with vertical intervals between the tube sheets; and an inlet water chamber and an outlet extending between the first and second tube sheets. an inner heat exchanger tube that communicates with the side water chamber; a first outer heat exchanger tube that extends between the third and fifth tube sheets and surrounds the inner heat exchanger tube at intervals in the radial direction; and a first outer heat exchanger tube that extends downward from the fifth tube sheet. a second outer heat transfer tube extending from the second tube sheet and having a vertical interval therebetween and surrounding the inner heat transfer tube with a radial interval therebetween; the upper part and the second and fifth
forming a passage communicating with the upper part of the space between the tube sheets, and providing an inlet for liquid low-temperature liquefied gas at the lower part of the space between the third and fourth tube sheets, the space between the first and third tube sheets; A vaporizer for low-temperature liquefied gas, characterized in that a gas outlet is provided at the top of the liquefied gas. (5) A riser is interposed between the low-temperature liquefied gas vaporizer and the low-temperature liquefied gas supply source that pumps the liquid low-temperature liquefied gas to the vaporizer, so that the liquid level is maintained within the riser. The method is characterized in that means is provided for supplying the low-temperature liquefied gas from the supply source to the riser pipe, thereby supplying the vaporized low-temperature liquefied gas to the standby vaporizer to cool the vaporizer. Cooling device for low temperature liquefied gas vaporization equipment.