JPH06235498A - Recovery of residual gas in liquefied gas vessel and its device - Google Patents

Abstract

PURPOSE:To provide a residual gas recovery method and its device capable of preventing lowering of recovery speed of liquefied gas in a storage tank caused by shortage of heat exchange even in the case when temperature rises, and reducing a load of a compressor. CONSTITUTION:A liquefied gas vessel M containing residual gas is connected to introduction pipes 32, 33 extending to the neighbourhood of inward bottom parts of fractional distillation tanks 2A, 2B, and heat of vaporized gas discharged from a compressor 31 is released by operation of heat exchanging parts 20A, 20B arranged in the fractional distillation tanks 2A, 2B and it is liquefied. Thereafter, by connecting it to an introduction pipe 44 extending to the neighhourhood of an inward bottom part of a storage tank 6 through a liquefied gas taking-out pipe 23, the liquefied gas liquefied in heat exchanging parts in the fractional distillation tanks 2A, 2B is delivered to the storage tank 6. Thereafter, by flowing cooling water in a water cooling pipe 41 built in the storage tank 6, unfractionated vaporized gas contained in the liquefied gas is cooled down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for recovering residual gas in a liquefied gas container containing liquefied petroleum gas or the like.

[0002]

2. Description of the Related Art Generally, in a liquefied gas container (hereinafter referred to as "container") for containing liquefied petroleum gas, a container inspection such as pressure resistance or airtightness, which is stipulated by law, is performed. Therefore, it is necessary to completely remove the residual gas in the container, that is, the vaporized gas and the liquefied gas, before conducting the inspection. Since these liquefied petroleum gases are flammable, there is a danger of explosion when released into the atmosphere, and since the liquid content usually contains oil content, the discharge of the liquid content causes a particular odor. It is necessary to completely recover the residual gas in the container because the problem of water pollution is severe.

As a conventional device for recovering the residual gas in the container, for example, the device disclosed in Japanese Patent Publication No. 48-9409 is known. When this apparatus is shown in FIG. 3, 100 is a container, 101 is a first gas recovery pipe,
102 is a fractionating tank, 103 is a second gas recovery pipe, 104 is a compressor, 105 is a cooler, and 106 is a storage tank. When the compressor 104 is driven during operation to suck the vaporized gas in the vapor phase portion in the fractionation tank 102, the vapor phase portion in the fractionation tank 102 is decompressed, whereby the container 1
00 and the fractionating tank 102 generate a pressure difference, and the container 100
The liquid phase portion therein flows into the fractionating tank 102, and further vaporized gas subsequently flows therein. The vaporized gas in the fractionating tank 102 sucked by the compressor 104 is cooled by the cooler 105.
At the same time, it is cooled and heat energy is taken away, so that it is liquefied and recovered in the storage tank 106. The vaporized gas in the storage tank 106 is returned to the first gas recovery pipe 101 via the vaporized gas recovery pipe 107.

However, in the recovery device shown in FIG.
Since the heat of vaporization is required when the liquefied gas in the fractionating tank 102 is vaporized, the temperature in the fractionating tank 102 is lowered, which slows the vaporization rate of the liquefied gas and finally the vaporization stops. The liquefied gas may fill up, so the operation of the device must be interrupted until the temperature recovers,
Especially in winter, the interruption time becomes long, and there is a drawback that the residual gas cannot be collected smoothly. Further, when the inside of the container is washed after the residual gas is collected, the adhered components inside the container are released together with the chemicals and steam, which causes a problem that the odor diffuses.

In order to address the above problems, the applicant of the present application has previously filed Japanese Patent Application No. 57-196100 (Japanese Patent Publication No. 62-578).
No. 75), the device shown in FIG. 4 was proposed. To briefly explain this, a plurality of containers M having residual gas
Is connected to the first gas recovery pipe 1, the unseparated liquefied gas is introduced directly into the fractionation tanks 2A, 2B from the on-off valve V1, and the compressor is operated with the on-off valve V3 of the vaporized gas recovery pipe 3 open. By operating 31 the fractionating tanks 2A, 2
The pressure of the gas phase portion in B decreases, and due to this pressure difference, the liquid portion in the container M flows into the fractionation tanks 2A, 2B and receives heat from the heat exchange portions 20A, 20B to be vaporized, It is introduced into the compressor 31 through the vaporized gas recovery pipe 3 commonly connected to the tops of the fractionating tanks 2A and 2B, and is compressed and heated. 10 is a pressure gauge, 12 is a strainer equipped with a magnet for removing iron powder and the like contained in the liquid content of the first gas recovery pipe 1, and 13 is a site for monitoring the flow state of liquefied gas. It is a glass.

The vaporized gas is used as the heat exchange parts 20A and 20B.
When passing through, the heat is taken away and liquefied. This liquefied gas is sent to the first storage tank 6 through the liquefied gas take-out pipe 23. When the on-off valve V2 is opened and the on-off valve V3 is closed after it is confirmed by the sight glass 13 that all the liquid content in the container M is collected, the check valve 14 is closed and the vaporized gas in the container M is Compressor 3 via gas recovery pipe 4
1, the compressor 31 compresses and heats up, and then the heat exchange sections 20A and 20B in the fractionation tanks 2A and 2B.
To become the liquefied gas and sent to the first storage tank 6 through the liquefied gas take-out pipe 23.

The pressure inside the container M is, for example, 500 mmH.
When it becomes g to 600 mmHg, the pressure switch PS operates and the operation of the compressor 31 is stopped. When the open / close valve V4 is opened and the open / close valve V1 and the open / close valve V2 are closed while the compressor 31 is operated, the liquefied gas having a high temperature flows into the first storage tank 6 by the operation of the compressor 31, and The pressure in the storage tank 6 rises and liquefied gas is jetted into the container M through the liquefied gas supply pipe 61, and the jetted liquefied gas cleans the inside of the container M. Container M
The amount of liquefied gas used for cleaning the inside is 6
This can be confirmed by observing the flow state of the liquefied gas through 0. After the cleaning of the inside of the container M is completed, the opening / closing valve V4 is closed and the opening / closing valve V1 is opened, whereby the container M
The liquefied gas inside is the fractional distillation tank 2 as in the case of recovering the liquid content.
It is sent to the inside of A and 2B, where it is fractionated and sent to the first storage tank 6.

Regarding the liquefied gas stored in the first storage tank 6, by operating the compressor 31, the liquefied gas having a high temperature flows into the storage tank 6 and the pressure in the tank rises. , 7 to flow into the second storage tank 7 via the liquefied gas recovery pipe 65.

[0009]

According to such a residual gas recovery apparatus, the heat exchange section 20A is provided in the fractionating tanks 2A, 2B for the cooling portion for liquefying the vaporized gas taken out from the fractionating tanks 2A, 2B. , 20B, the vaporized gas radiates heat to the liquefied gas in the fractionating tank in the heat exchange section to be liquefied, and at the same time, heat of vaporization is replenished from the compressed gas heated by the compressor, It is possible to suppress a decrease in the temperature of 2A and 2B, prevent a decrease in the vaporization rate of the liquefied gas, and continuously collect the residual gas in the container. Further, the inside of the container can be cleaned by using the liquefied gas recovered in the storage tank 6 and ejecting this into the container M by the operation of the compressor 31, and the liquefied gas after cleaning is recovered again through the gas recovery pipe 3. Therefore, the advantage that there is no diffusion of odor can be exhibited.

However, when such a residual gas recovery device is used, the temperature of the residual gas in the container M rises and the cooling in the fractionation tanks 2A and 2B is insufficient when the temperature rises in summer or the like. The amount of the vaporized gas fractionated by the heat exchanger increases, and particularly when the amount of the liquid in the fractionating tanks 2A, 2B decreases, the heat exchange parts 20A, 2A connected to the discharge side of the compressor 31.
Since the contact surface between 0B and the liquid is reduced, heat exchange is not sufficiently performed, and there is a problem that the recovery rate of the liquefied gas in the first storage tank 6 is reduced.

Particularly, regarding the liquefied gas stored in the first storage tank 6, the pressure inside the storage tanks 6 and 7 is increased by the operation of the compressor 31, and the liquefied gas is caused to flow into the second storage tank 7 due to the pressure difference between the storage tanks 6 and 7. Therefore, when the amount of the vaporized gas to be fractionated is increased, the load on the compressor 31 is also greatly increased, and the liquefied gas is initially collected in the second storage tank 7. In the latter half, however, there is a problem that the temperature and pressure inside the recovery pipe 65 become high due to the collision of molecules with the inner wall of the container and the collision between molecules, and the inflow of liquefied gas is stopped.

Therefore, the present invention solves the problem of the residual gas recovery device shown in FIG. 4 and liquefies the storage tank due to insufficient heat exchange even when the ambient temperature rises. It is an object of the present invention to provide a residual gas recovery method and apparatus capable of preventing a decrease in gas recovery rate and reducing the load on a compressor.

[0013]

In order to achieve the above object, the present invention provides a liquefied gas container having a residual gas to the vicinity of the inner bottom of a fractionation tank through a gas recovery pipe and an unseparated intake pipe. The heat of the vaporized gas discharged from the compressor in the fractionating tank is radiated and liquefied by the action of the heat exchange section arranged in the fractionating tank, which is connected to the extending introducing pipe, and liquefies from the heat exchanging section. By connecting the gas through a liquefied gas extraction pipe to an introduction pipe that extends to the vicinity of the inner bottom of the storage tank, the vaporized gas in the vapor phase portion in the fractionation tank is sucked by the compressor to reduce the pressure in the vapor phase portion. The liquefied gas remaining in the liquefied gas container was introduced into the fractionation tank through the gas recovery pipe, and the liquefied gas liquefied in the heat exchange section in the fractionation tank was sent to the storage tank and was installed in the storage tank. Liquefaction by circulating cooling water through the water cooling pipe To provide an arrangement of the residual gas recovery method of the liquefied gas in the container to cool the scan. In addition, an introduction pipe extending from the liquefied gas container having the residual gas to the vicinity of the inner bottom of the fractionation tank through the gas recovery pipe and the unseparated intake pipe is provided, and the vaporized gas discharged from the compressor into the fractionation tank. Is provided with a heat exchange part for radiating the heat of the liquid phase to the liquid phase part in the fractionating tank to condense and liquefy the vaporized gas, and contains the liquefied gas from the heat exchange part and obtains cooling water from an external water source. A storage tank equipped with a water-cooling pipe that circulates the gas is provided, and the complex is used to suction the vaporized gas in the vapor phase portion of the fractionation tank to decompress the vapor phase portion and recover the liquefied gas remaining in the liquefied gas container. Provided is a structure of a residual gas recovery device in a liquefied gas container that causes a liquefied gas condensed and liquefied in a heat exchange section in the fractionation tank to flow into the storage tank while flowing into the fractionation tank through a pipe.

[0014]

According to such residual gas recovery method and apparatus,
From the residual gas discharged from the container, the liquid component that has flowed into the fractionation tank receives the heat from the heat exchange section and is vaporized, and is introduced into the compressor via the vaporized gas recovery pipe and compressed,
The temperature of the vaporized gas rises, and heat is deprived of the vaporized gas in the heat exchange section to be liquefied. The liquefied gas is sent to the storage tank through the liquefied gas take-out pipe, and is led to the vicinity of the bottom of this storage tank where it is released.At this time, by supplying cooling water to the water cooling pipe installed in the storage tank, The fractionated vaporized gas contained in is cooled, and the recovery rate of the liquefied gas in the storage tank is increased. Therefore, even in the summer when the ambient temperature rises, the collection speed of the liquefied gas in the storage tank is prevented from decreasing due to insufficient heat exchange in the fractionation tank, and the load on the compressor is reduced. The cooling action is further enhanced by projecting the cooling fins on the water-cooling pipe installed in the storage tank.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for recovering a residual gas in a liquefied gas container and an apparatus therefor according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing the present embodiment as a whole, and 1 in the drawing is a first gas recovery pipe, and the residual gas should be recovered at one end side of the first gas recovery pipe 1. A plurality of container connection parts 11 and 11 to which the container M is connected are provided. An opening / closing valve VA is attached to the container connecting portion 11. 1
0 is a pressure gauge.

The first gas recovery pipe 1 is equipped with a strainer 12 having a magnet for removing iron powder and the like contained in the liquid content in the container, and a sight glass 13 for monitoring the distribution state. A check valve 14 and an on-off valve V1 are provided. The unseparated liquid intake pipe 30 for oil or the like connected to the on-off valve V1 is connected to the two introduction pipes 32 and 33 at the branch point C via the valves V6 and V7, and one introduction pipe 32 is divided. It is introduced into the distilling tank 2A, further extends to the vicinity of the inner bottom of the distilling tank 2A, an outlet 32a is provided at the tip, and the other introducing pipe 33 is introduced into the distilling tank 2B. An outlet 33a is provided at the tip end of the fractionation tank 2B extending to the vicinity of the inner bottom. D is a drain reservoir provided in the unseparated intake pipe 30.

The first fractionation tank 2A and the second fractionation tank 2B
Inside, heat exchange sections 20A, 20B are provided which are tubes formed in a coil shape so as to extend in the vertical direction.

The outlets of a common vaporized gas recovery pipe 3 are connected to the tops of the fractionation tanks 2A and 2B, and an on-off valve V3 and a compressor 31 are connected to the vaporized gas recovery pipe 3. The compressor 31 has a pressure switch for stopping the operation of the compressor 31 when the pressure on the inlet side of the compressor 31 becomes lower than a predetermined pressure or when the pressure on the outlet side becomes higher than a predetermined pressure. PS is provided.

Reference numeral 21 is a drain pipe for discharging the oil content contained in the liquid content in the fractionation tanks 2A and 2B to the outside of the fractionation tanks 2A and 2B. The compressor 31
At the outlet of the heat exchanger 20 provided in the first fractionating tank 2A.
The upper end of A is connected, and the lower end of this heat exchange part 20A and the upper end of the heat exchange part 20B in the second fractionation tank 2B are connected by a connecting pipe 22. Further, the first gas recovery pipe 1 to the second gas recovery pipe 4 are branched at the position of the sight glass 13, and the second gas recovery pipe 4 is provided with the opening / closing valve V3 and the compressor 31 in the vaporized gas recovery pipe 3. Connected between. The second gas recovery pipe 4 is provided with an on-off valve V2 and a filter F for filtering metal powder and the like.

A flow path switching mechanism 5 for switching the flow path between the first gas recovery pipe 1 and the second gas recovery pipe 4 is provided. In the illustrated example, the flow path switching mechanism 5
Is an on-off valve V1 provided on the first gas recovery pipe 1 or an on-off valve V2 provided on the second gas recovery pipe 4. Then, the lower end of the heat exchange section 20B in the second fractionation tank 2B is connected to the vicinity of the upper portion of the first storage tank 6 via the liquefied gas extraction pipe 23. Reference numeral 61 is a liquefied gas supply pipe for cleaning, which supplies the liquefied gas in the first storage tank 6 to the container as a cleaning liquid. The liquefied gas supply pipe 61 has a first inlet.
A plurality of liquefied gas feed pipes 62 each having an opening / closing valve VB are connected to the lower part of the storage tank 6 and the liquefied gas feed pipes 62 are respectively connected to the first container connecting portion 11.

V4 is an on-off valve, and 60 is a sight glass. A gas discharge pipe 63 having a safety valve SV at the tip is connected to the top of the first storage tank 6, and a branch pipe 631 branched from the gas discharge pipe 63 is connected to the vaporized gas recovery pipe 3 via an opening / closing valve V5. It is connected. This branch pipe 631 is provided with the first storage tank 6 when the pressure in the first storage tank 6 becomes too high.
It is used to return the gas in the storage tank 6 to the vaporized gas recovery pipe 3. Reference numeral 64 is a drain pipe of the first storage tank 6.

A spiral water cooling pipe 41 is provided inside the first storage tank 6, a water source 42 provided outside is connected to the lower end of the water cooling pipe 41, and the upper end of the water cooling pipe 41 is connected. The part is connected to the discharge pipe 43. The upper end of the liquefied gas take-out pipe 23 is connected to an introduction pipe 44 arranged in the second storage tank 6, and the introduction pipe 44 extends to the vicinity of the inner bottom of the second storage tank 6 and has a tip end portion. Is provided with an outlet 45. Further, in the spiral water cooling pipe 41 installed in the first storage tank 6, a large number of cooling fins 46 shown in FIG.
46 is projected.

Further, a second storage tank 7 for recovering the liquefied gas in the storage tank 6 is connected to the first storage tank 6 through a liquefied gas recovery pipe 65, and this second storage tank 7 is connected. The liquefied gas inside is vaporized and sent to the combustion equipment in the factory.

Next, the process of recovering the residual gas in the container M, which is performed using the above-mentioned apparatus, will be described. First, the container M having the residual gas is connected to the first container connecting portion 11 in a state of being tumbled. Normally, the residual gas in each container is simultaneously recovered by connecting a plurality of containers to the container connecting portion 11. First, the on-off valve V1 of the first gas recovery pipe 1 and the on-off valve V3 of the vaporized gas recovery pipe 3 are opened, and the on-off valve V2 of the second gas recovery pipe 4 and the on-off valve V4 of the liquefied gas supply pipe 61 are opened.
When the drive of the compressor 31 is started under this state, the pressure of the gas phase portion in the fractionation tanks 2A and 2B decreases, and the pressure difference between the gas phase portion and the container M causes The liquid portion is the unseparated liquid intake pipe 30, the valves V6 and V7, and the two introduction pipes 32 and 33 from the first gas recovery pipe 1.
Through the outlets 32a, 33a provided in the vicinity of the inner bottoms of the respective fractionation tanks 2A, 2B.

Therefore, the unseparated liquid such as oil in the container M is
The liquefied gas in the liquid component that flows out from the outlets 32a and 33a provided near the inner bottoms of the fractionation tanks 2A and 2B and flows out into the fractionation tanks 2A and 2B is the heat exchange section 20A, Two
The heat from 0B is received and vaporized, and this vaporized gas is introduced into the compressor 31 through the vaporized gas recovery pipe 3 where it is compressed and the temperature rises. Then, the vaporized gas sequentially passes through the heat exchange units 20A and 20B, and the heat exchange units 20A and 20B
At 0B, the heat of the vaporized gas is taken and liquefied. The liquefied gas thus liquefied is sent to the first storage tank 6 through the liquefied gas extraction pipe 23. These two introduction tubes 3
Due to 2, 33, entrainment of oil and the like in the unseparated liquid is eliminated or becomes extremely small.

The liquefied gas is guided to the vicinity of the bottom of the first storage tank 6 by the introduction pipe 44 and discharged from the outflow port 45. At this time, by supplying the cooling water from the water source 42, the cooling water is generated. By passing through the spiral water cooling pipe 41 installed in the first storage tank 6 and being discharged from the discharge pipe 43, the vaporized gas fractionated and contained in the liquefied gas is sufficiently cooled, The recovery rate of the liquefied gas in the first storage tank 6 can be increased. Especially, even in the summer when the ambient temperature rises, it is possible to prevent a decrease in the recovery rate of the liquefied gas in the first storage tank 6 due to a lack of heat exchange in the fractionation tanks 2A and 2B, and reduce the load on the compressor 31. You can do it. The cooling action is further enhanced by providing a large number of cooling fins 46, 46 on the water cooling pipe 41 internally fed to the first storage tank 6.

When the amount of the vaporized gas to be fractionated further increases, an abnormal increase in temperature and pressure in the recovery pipe 65 due to collision of molecules with the inner wall of the container or collision between molecules is prevented, An effect that the liquefied gas is smoothly collected in the second storage tank 7 can be obtained.

Next, it is confirmed by the sight glass 13 that all the liquid content in the container M has been recovered, and then the on-off valve V2
When the open / close valve V3 is closed and the compressor 31 is operated, the check valve 14 is closed and the vaporized gas in the container M is sent to the compressor 31 via the second gas recovery pipe 4. The same effect can be obtained by closing the open / close valve V1.

The vaporized gas thus introduced into the compressor 31 is compressed and heated by the compressor 31 and then passes through the heat exchanging sections 20A and 20B to generate heat as in the case of vaporized gas from the fractionating tanks 2A and 2B. It is liquefied into liquefied gas in the exchange sections 20A and 20B, and this liquefied gas is sent to the first storage tank 6 via the liquefied gas extraction pipe 23. The pressure in the container M is, for example, 500 mmHg-60.
When the pressure reaches 0 mmHg, the pressure switch PS1 operates to stop the operation of the compressor 31, and the inside of the container M in which the liquid component and the vaporized gas are recovered is washed with the liquefied gas in the first storage tank 6. That is, the open / close valve V4 is opened while the compressor 31 is operating, and the open / close valves V1 and V2 are opened.
When is closed, the liquefied gas having a high temperature flows into the first storage tank 6 by the operation of the compressor 31, the pressure in the first storage tank 6 rises, and the pressure in the container M further decreases. The liquefied gas in the first storage tank 6 is jetted into the container M through the liquefied gas supply pipe 61, and the jet of the liquefied gas cleans the inside of the container M. The amount of the liquefied gas used for cleaning the inside of the container M is, for example, about 5% of the volume of the container M, and whether or not a predetermined amount of the liquefied gas is supplied into the container M is determined via the sight glass 60. It can be confirmed by observing the state of the liquefied gas flow.

After the washing of the container M is completed, the on-off valve V4
Is closed and the on-off valve V1 is opened, whereby the liquefied gas in the container M is sent to the fractionation tanks 2A and 2B as in the case of collecting the liquid content, where it is vaporized and sent to the first storage tank 6. Be done. Further, for a container in which the liquid component does not remain or the amount of the remaining liquid is very small, only the cleaning process may be performed without passing through the liquid component and vaporized gas recovery process.

With respect to the liquefied gas stored in the first storage tank 6, by operating the compressor 31, the liquefied gas having a high temperature flows into the storage tank 6 and the tank internal pressure rises. , 7 to flow into the second storage tank 7 via the liquefied gas recovery pipe 65.

[0032]

As described in detail above, according to the present invention, the liquefied gas from the heat exchange section is connected to the introduction pipe extending to the vicinity of the inner bottom of the storage tank, and is liquefied in the heat exchange section in the fractionation tank. Included in the liquefied gas by sending the liquefied gas to the storage tank and circulating cooling water through a water-cooling pipe installed in the storage tank to cool the fractionated vaporized gas contained in the liquefied gas. The fractionated vaporized gas is cooled in the storage tank, and the recovery rate of the liquefied gas in the storage tank can be increased. In particular, even in the summer when the ambient temperature rises, it is possible to prevent a decrease in the recovery rate of the liquefied gas in the storage tank due to the lack of heat exchange in the fractionation tank and reduce the load on the compressor. In addition, since the introduction pipe is installed, the entrainment of oil and the like in the unseparated liquid is eliminated, or the amount becomes extremely small, so that the high quality liquid can be recovered. Further, by providing the cooling fins on the water-cooled pipe installed in the storage tank, the above-mentioned cooling effect can be further enhanced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a residual gas recovery device according to the present invention.

FIG. 2 is a plan sectional view of a water cooling pipe.

FIG. 3 is a schematic diagram showing an example of a conventional residual gas recovery device.

FIG. 4 is a schematic diagram showing another example of a conventional residual gas recovery device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st gas recovery pipe 11 ... Container connection part 2A, 2B ... Fractionation tank 20A, 20B ... Heat exchange part 3 ... Vaporized gas recovery pipe 31 ... Compressor 4 ... Second gas recovery pipe 5 ... Flow path switching mechanism 6 ... 1st storage tank 61 ... Liquefied gas supply pipe for cleaning 7 ... 2nd storage tank 22 ... Connection pipe 23 ... Liquefied gas taking-out pipe 30 ... Unseparated liquid taking-in pipe 31 ... Compressor 32, 33, 44 ... Introducing pipe 32a , 33a ... Outlet port 41 ... Water cooling pipe 42 ... Water source 43 ... Discharge pipe 46 ... Cooling fin 61 ... Liquefied gas supply pipe 63 ... Gas discharge pipe 65 ... Liquefied gas recovery pipe M ... Container

Claims (3)

[Claims] 1. A liquefied gas container having residual gas is connected to an introduction pipe extending to the vicinity of an inner bottom of a fractionation tank through a gas recovery pipe and an unseparated intake pipe, and a compressor is provided in the fractionation tank. The heat of the discharged vaporized gas is radiated and liquefied by the action of the heat exchange section arranged in the fractionation tank, and the liquefied gas from this heat exchange section is in the vicinity of the inner bottom of the storage tank through the liquefied gas extraction pipe. It is connected to an inlet pipe that extends up to, and the liquefied gas remaining in the liquefied gas container is separated through the gas recovery pipe by sucking the vaporized gas in the gas phase portion in the fractionating tank with a compressor and depressurizing the gas phase portion. Cooling the liquefied gas by flowing into the distilling tank and sending the liquefied gas liquefied in the heat exchange section in the distilling tank to the storage tank, and circulating the cooling water through the water cooling pipe installed in the storage tank. Residual gas in liquefied gas container characterized by Recovery method. 2. An introduction pipe extending from the liquefied gas container having residual gas to the vicinity of the inner bottom of the fractionation tank through a gas recovery pipe and an unseparated intake pipe is provided, and the compressor is discharged into the fractionation tank. A heat exchange unit is provided for radiating heat of the vaporized gas to a liquid phase portion in the fractionating tank to condense and liquefy the vaporized gas,
A storage tank containing a liquefied gas from the heat exchange section and a water cooling pipe that circulates cooling water obtained from an external water source is provided, and the complex serves to suck the vaporized gas in the vapor phase portion in the fractionation tank. The gas phase part is decompressed and the liquefied gas remaining in the liquefied gas container is caused to flow into the fractionation tank through the gas recovery pipe, and the liquefied gas condensed and liquefied in the heat exchange section in the fractionation tank is stored in the storage tank. A residual gas recovery device in a liquefied gas container characterized by being fed. 3. The residual gas recovery device in a liquefied gas container according to claim 2, wherein a cooling fin is provided in a protruding manner on a water cooling pipe 41 provided inside the storage tank.