JPH1182895A - Low temperature storage installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost and installation area. SOLUTION: A low temperature storage installation is provided with a low temperature storage tank 2 that can store low temperature liquid 1, a boil-off gas(BOG) pipe 16 for leading evaporated gas 15 generated in the low temperature storage tank 2, to the outside, A receiving pipe 6 diverged into an upper receiving pipe 7 for transferring the low temperature liquid 1 to the upper part of the low temperature storage tank 2, and a lower receiving pipe 8 for transferring the low temperature liquid 1 to the lower part of the low temperature storage tank 2, and a liquid drain pipe 25 for leading the low temperature liquid 1 accomulated in a vertical part 10 of the upper receiving pipe 7, to the outside. Such a low temperature storage installation is provided with a liquid drain drum 32 serving as a BOG suction drum provided at its upper part with a mist separator 21 for separating mist 20 contained in the evaporated gas 15 from the BOG pipe 16 and provided ast its lower part with a liquid reservoir part that can store the low temperature liquid 1 fed from the vertical part 10 of the upper receiving pipe 7 through the liquid drain pipe 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature storage facility, and more particularly, to a low-temperature storage facility capable of reducing costs and reducing an installation area.

[0002]

2. Description of the Related Art Cryogenic storage facilities are used to store cryogenic liquids such as liquefied natural gas (LNG).

[0003] As shown in FIG.
The low-temperature storage tank 2 mainly includes a low-temperature storage tank 2 such as an LNG tank that stores the low-temperature liquid 1.
A liquid sending pipe 5 and a receiving pipe 6 for sending the low-temperature liquid 1 from the ship 3 to the low-temperature storage tank 2 using the pump 4 mounted on the ship 3 are provided. It branches into an upper receiving pipe 7 connected to the upper part of the storage tank 2 and a lower receiving pipe 8 connected to the lower part of the low temperature storage tank 2.

[0004] Incidentally, reference numeral 9 denotes a valve provided in the vertical portion 10 of the upper receiving pipe 7, and reference numeral 11 denotes a valve provided in the middle of the lower receiving pipe 8.

[0005] In order to keep the liquid sending pipe 5 and the receiving pipe 6 in a cooled state, a replenishing pump 12 and a level adjusting valve are provided between the bottom of the low-temperature storage tank 2 and the liquid sending pipe 5 or the receiving pipe 6. 1
3 is provided.

[0006] Further, an evaporative gas 15
A BOG tube 16 (BOG = boil-off gas) for taking out the air to the outside is attached.
Via the G suction drum 17 and the compressor 18
It is connected to a gas sending pipe 19 for sending to a demand destination.

The BOG suction drum 17 is provided with a mist separator 21 such as a wire mesh for separating a mist 20 in the evaporative gas 15 at the upper part. The mist separator 21 separates the BOG suction drum 17 from the mist separator 21. A return pipe 23 is provided for returning the low-temperature liquid 1 accumulated in the lower portion by condensing the mist portion 20 to the upper portion of the low-temperature storage tank 2 using a pump 22.

Further, a drain pipe 25 for sending the low-temperature liquid 1 accumulated in the vertical portion 10 of the upper receiving pipe 7 to the drain drum 24 is connected to the liquid sending pipe 5 or the receiving pipe 6.
An opening / closing valve 26 is provided on the liquid draining tube 25 on the side of the liquid draining drum 24, and a limiting orifice 27 is provided in parallel with the opening / closing valve 26.

The low temperature liquid 1 of the liquid draining drum 24 is returned to the upper part of the low temperature storage tank 2 by using a pump 30 at the lower part of the liquid draining drum 24 based on a liquid level detection signal 29 from a liquid level detector 28. A return pipe 31 is provided.

According to such a configuration, the low-temperature liquid 1 such as LNG gas is stored in the low-temperature storage tank 2 such as an LNG tank. The low-temperature liquid 1 is evaporated. Then, the evaporation gas 15 generated by the evaporation
Is sent from the upper part of the low-temperature storage tank 2 to the compressor 18 via the BOG pipe 16, pressurized to a required pressure by the compressor 18, and then sent to the demand destination via the gas sending pipe 19.

Prior to compression by the compressor 18, the BO
BOG suction drum 1 provided in the middle of G tube 16
7, the mist separator 20 such as a wire mesh separates the mist 20 in the evaporative gas 15 so that the evaporative gas 15 can be easily compressed by the compressor 18.
To be compressed.

The mist 20 separated by the mist separator 21 is condensed and accumulated in the lower part of the BOG suction drum 17. BOG suction drum 17
When the low temperature liquid 1 has accumulated to the lower part of the pump, the pump 22
Is driven to return to the upper part of the low-temperature storage tank 2 via the return pipe 23.

On the other hand, since the liquid sending pipe 5 and the receiving pipe 6 cannot pass the low-temperature liquid 1 from the room temperature state immediately, the required amount of the low-temperature liquid 1 is stored in the liquid sending pipe 5 or the receiving pipe 6. Must always be stored, and the liquid sending pipe 5 and the receiving pipe 6 must be kept in a cooled state.

For this purpose, the level of the low-temperature liquid 1 in the liquid sending pipe 5 and the receiving pipe 6 is detected by a level detector (not shown) or the like, and when the liquid level becomes low, the supply pump 12 is driven and the level is adjusted. The valve 13 is opened, and the low-temperature liquid 1 is supplied from the bottom of the low-temperature storage tank 2 to the liquid sending pipe 5 or the receiving pipe 6 via the supply pipe 14. In addition, the liquid sending pipe 5
Alternatively, when the low-temperature liquid 1 is supplied to the receiving pipe 6, the supply pump 12 is automatically stopped, and the level adjustment valve 13 is automatically closed.

When the ship 3 filled with the low-temperature liquid 1 arrives, the pump 3 mounted on the ship 3 is driven, so that the ship 3 is loaded on the ship 3 via the liquid sending pipe 5 and the receiving pipe 6. The low-temperature liquid 1 is transferred to the low-temperature storage tank 2.

At this time, the density of the cryogenic liquid 1 from the ship 3
The density of the low-temperature liquid 1 stored in the low-temperature storage tank 2 is checked, and when the density of the low-temperature liquid 1 from the ship 3 is higher, the valve 11 of the lower receiving pipe 8 is closed, and the valve of the upper receiving pipe 7 is closed. By opening 9, the low-temperature liquid 1 is introduced from above the low-temperature storage tank 2 through the upper receiving pipe 7. Conversely, if the density of the cryogenic liquid 1 from the ship 3 is smaller, the valves 11 and 9
By opening both, the low-temperature liquid 1 is introduced from the lower side of the low-temperature storage tank 2 through the lower receiving pipe 8. Thereby, it is possible to prevent the low-temperature liquid 1 in the low-temperature storage tank 2 from separating into two phases due to the density difference.

When the low-temperature liquid 1 is introduced from below the low-temperature storage tank 2, the valve 9 is opened so that the gas contained in the low-temperature liquid 1 is allowed to escape to the upper receiving pipe 7 side. To do that. When the valve 9 is opened as described above, the low-temperature liquid 1 enters the vertical portion 10 of the upper receiving pipe 7 to a liquid level equal to the liquid level of the low-temperature storage tank 2.

After the low-temperature liquid 1 is put into the low-temperature storage tank 2, the valves 9 and 11 are closed once.

When the valves 9 and 11 are closed as described above, the low-temperature liquid 1 remains in the vertical portion 10 of the upper receiving pipe 7, but the low-temperature liquid 1 remaining in the vertical portion 10 having a small diameter dimension.
Is likely to be in an unstable state (a state of intermittent boiling) due to heat input from the outside.

Therefore, conventionally, after the low-temperature liquid 1 is put into the low-temperature storage tank 2, the valve 9 and the opening / closing valve 26 are opened, so that the low-temperature liquid 1 remaining in the vertical portion 10 is
The liquid is sent to the draining drum 24 via the receiving pipe 6 and the draining pipe 25 so as to drain the liquid in the vertical portion 10.

The liquid level in the liquid draining drum 24 is detected by a liquid level detector 28.
When the liquid level of the liquid 4 becomes higher than the upper limit set value, the pump 30 is driven by the liquid level detection signal 29 from the liquid level detector 28, and the low temperature liquid 1 of the liquid draining drum 24 is cooled down through the return pipe 31. It will be returned to the upper part of the storage tank 2. Conversely, when the liquid level of the liquid draining drum 24 becomes lower than the lower limit set value, the pump 30 is stopped by the liquid level detection signal 29 from the liquid level detector 28. As described above, the liquid level of the liquid draining drum 24 is maintained within a certain range.

Since the liquid drain pipe 25 and the pump 30 cannot pass the low-temperature liquid 1 immediately from a normal temperature state, it is necessary to provide the liquid drain pipe 25 with a restriction orifice 27 in parallel with the on-off valve 26. As a result, a small amount of the low-temperature liquid 1 is constantly sent to the liquid draining drum 24 and the pump 30 through the restriction orifice 27, and these are kept at a low temperature.

[0023]

However, the above-mentioned conventional low-temperature storage equipment has the following problems.

That is, the low-temperature storage equipment includes the evaporative gas 1
5 is provided separately from the BOG suction drum 17 for separating the mist 20 in the mist 5, and the liquid draining drum 24 from which the low-temperature liquid 1 in the vertical portion 10 is drawn. Providing the drum 17 and the liquid draining drum 24 separately increases the cost, and requires a large area for installation.

The present invention has been made in view of the above circumstances, and has as its object to provide a low-temperature storage facility capable of reducing costs and reducing an installation area.

[0026]

SUMMARY OF THE INVENTION The present invention provides a low-temperature storage tank 2 capable of storing a low-temperature liquid 1, a BOG pipe 16 for guiding an evaporative gas 15 generated in the low-temperature storage tank 2 to the outside, and an upper part of the low-temperature storage tank 2. An upper receiving pipe 7 for transferring the low-temperature liquid 1, a receiving pipe 6 branched into a lower receiving pipe 8 for transferring the low-temperature liquid 1 to a lower part of the low-temperature storage tank 2, and a vertical portion 10 of the upper receiving pipe 7.
Low-temperature storage equipment provided with a drain pipe 25 for guiding the low-temperature liquid 1 accumulated in the tank through the receiving pipe 6 to the outside.
Mist 20 contained in evaporative gas 15 from OG pipe 16
BOG having a mist separator 21 for separating the low temperature liquid 1 from the vertical portion 10 of the upper receiving pipe 7 which is sent through the liquid draining pipe 25 at the bottom. The present invention relates to a low-temperature storage facility provided with a suction drum and liquid drainage drum 32.

According to the above means, the following effects can be obtained.

The evaporative gas 15 generated by evaporating the low-temperature liquid 1 stored in the low-temperature storage tank 2 due to heat input from the outside, etc., flows from the upper part of the low-temperature storage tank 2 to the BOG pipe 1.
The mist 20 is sent out to the outside through the mist separator 21 and separated by the mist separator 21 by the mist separator 21 at the middle of the BOG pipe 16.

Also, the low-temperature storage tank 2 is connected via the lower receiving pipe 8 or the like.
After the low-temperature liquid 1 has been introduced into the lower side of the container, the low-temperature liquid 1 remaining in the vertical portion 10 of the upper receiving pipe 7 is transferred to the BOG suction drum / liquid discharging drum 32 via the receiving pipe 6 and the liquid discharging pipe 25. And the liquid is drained from the vertical portion 10.

As described above, the BOG suction drum dual-purpose liquid draining drum 32 is provided, and the BOG suction drum dual-purpose liquid draining drum 32 is provided with the mist 20 in the evaporation gas 15.
, And the function of draining the low-temperature liquid 1 in the vertical portion 10 of the upper receiving pipe 7, so that the cost can be reduced and the installation area can be reduced.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

Regarding the basic configuration of the low-temperature storage facility,
2 are the same as those in FIG.

In this embodiment, the BOG tube 16
A mist separator 21 for separating a mist component 20 contained in the evaporated gas 15 from
A characteristic feature is that a BOG suction drum and liquid drainage drum 32 having a liquid storage part capable of storing the low-temperature liquid 1 from the vertical part 10 of the upper receiving pipe 7 sent through the liquid drainage pipe 25 is provided. is there.

Next, the operation will be described.

The basic operation of the low-temperature storage facility is the same as that of FIG.

In the present embodiment, the evaporative gas 15 generated by evaporating the low-temperature liquid 1 stored in the low-temperature storage tank 2 due to heat input from the outside or the like passes through the BOG pipe 16 from the upper part of the low-temperature storage tank 2. To the compressor 18 via
After being pressurized to a required pressure by the compressor 18, the gas delivery pipe 1
9 to the demand destination.

Then, prior to compression by the compressor 18,
The evaporative gas 15 is passed through a BOG suction drum and liquid drainage drum 32 provided in the middle of the BOG pipe 16, and the mist 20 in the evaporative gas 15 is separated by a mist separator 21 such as a wire mesh. At 18, the evaporative gas 15 is compressed.

The mist 20 separated by the mist separator 21 is condensed and stored in the lower part of the BOG suction drum and liquid drainage drum 32.

On the other hand, the low-temperature liquid 1 is transferred from the ship 3 to the lower side of the low-temperature storage tank 2 through the liquid sending pipe 5, the receiving pipe 6, and the lower receiving pipe 8.
, After opening the valve 9 and the on-off valve 26,
Using the gravity, the low-temperature liquid 1 left in the vertical portion 10 of the upper receiving pipe 7 is transferred through the receiving pipe 6 and the drain pipe 25 to B
The liquid is sent to the OG suction drum and liquid drainage drum 32 so that the liquid in the vertical portion 10 is drained.

Then, in the BOG suction drum and liquid drainage drum 32, the liquid level is detected by the liquid level detector 28. When the liquid level of the BOG suction drum and liquid drainage drum 32 becomes higher than the upper limit set value, The pump 30 is driven by the liquid level detection signal 29 from the liquid level detector 28, and the low temperature liquid 1 of the BOG suction drum and liquid drainage drum 32 is returned to the upper part of the low temperature storage tank 2 via the return pipe 31. . Conversely, when the liquid level of the BOG suction drum and liquid drainage drum 32 becomes lower than the lower limit set value, the pump 30 is stopped by the liquid level detection signal 29 from the liquid level detector 28. From the above,
The liquid level of the BOG suction drum and liquid drainage drum 32 is maintained within a predetermined range.

Since the low-temperature liquid 1 cannot be immediately passed through the drain tube 25 and the pump 30 from the room temperature state, a restricting orifice 27 is provided in the drain tube 25 in parallel with the on-off valve 26. A small amount of the low-temperature liquid 1 is constantly sent to the BOG suction drum and liquid drain drum 32 and the pump 30 through the restriction orifice 27 so that these are kept at a low temperature.

As described above, the BOG suction drum dual-purpose liquid draining drum 32 is provided, and the BOG suction drum dual-purpose liquid draining drum 32 is provided with the mist 20 in the evaporation gas 15.
, And the function of draining the low-temperature liquid 1 in the vertical portion 10 of the upper receiving pipe 7, so that the cost can be reduced and the installation area can be reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

[0045]

As described above, according to the low-temperature storage facility of the present invention, it is possible to achieve an excellent effect that the cost can be reduced and the installation area can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram of an example of an embodiment of the present invention.

FIG. 2 is a schematic system diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low-temperature liquid 2 Low-temperature storage tank 6 Receiving pipe 7 Upper receiving pipe 8 Lower receiving pipe 10 Vertical part 15 Evaporation gas 16 BOG pipe 20 Mist 21 Mist separator 25 Liquid drain pipe 32 BOG suction drum and liquid drain drum

Claims (1)

[Claims] A low-temperature storage tank (2) capable of storing a low-temperature liquid (1), and an evaporative gas (1) generated in the low-temperature storage tank (2).
BOG pipe (16) for guiding 5) to the outside, and low-temperature storage tank (2)
An upper receiving pipe (7) for transferring the low-temperature liquid (1) to the upper part of the container and a receiving pipe branched to a lower receiving pipe (8) for transferring the low-temperature liquid (1) to the lower part of the low-temperature storage tank (2). (6) and a liquid drainage pipe (25) for guiding the low-temperature liquid (1) accumulated in the vertical portion (10) of the upper receiving pipe (7) to the outside via the receiving pipe (6). A mist separator (21) for separating a mist (20) contained in the evaporative gas (15) from the BOG pipe (16) at the upper part, and a lower part via a liquid drain pipe (25). The vertical part (1) of the upper receiving pipe (7)
A low-temperature storage facility comprising a BOG suction drum and liquid drainage drum (32) having a liquid storage portion capable of storing the low-temperature liquid (1) from (0).