JP2009103165A - Low temperature liquefied gas transport vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low temperature liquefied gas transport vehicle not discharging hydrogen gas in an on-vehicle tank to the atmosphere even if low temperature liquefied gas is continuously supplied to a plurality of consumers. <P>SOLUTION: This vehicle is provided with a means extracting gas phase gas in the on-vehicle tank 1, and an auxiliary tank 3 storing the extracted gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a low-temperature liquefied gas transport vehicle. The low-temperature liquefied gas transport vehicle (hereinafter simply referred to as “transport vehicle”) means an automobile equipped with an in-vehicle tank that stores the low-temperature liquefied gas. Structurally, it is similar to a lorry vehicle that transports oil and gasoline, but differs in that what is loaded is "low temperature liquefied gas".
“Low-temperature liquefied gas” refers to a gas that exists in a gas (gas) state at room temperature, but liquefies when the temperature of the gas is lowered (for example, −180 ° C. or lower). Examples of the “low temperature liquefied gas” include “air”, “oxygen”, “nitrogen”, “argon”, “hydrogen”, “helium” and the like.
When “cold liquefied gas” is stored in the vehicle tank, a gas phase portion is formed on the liquid phase portion inside the vehicle tank. The gas phase portion formed on the liquid phase portion is particularly referred to as “gas phase gas”.
In the following description, “hydrogen” means hydrogen in terms of physical properties, and indicates an arbitrary state such as gas or liquid. The description of “hydrogen gas” particularly means hydrogen in a gaseous state. The description of “liquefied hydrogen” means in particular liquid hydrogen. When “liquefied hydrogen” is stored in an in-vehicle tank, a part of “liquefied hydrogen” is vaporized, and “hydrogen gas” as “gas phase gas” is formed on “liquefied hydrogen”.

  Due to the recent increase in global environmental regulations, hydrogen that can be produced from various raw materials such as fossil fuels, biomass, and water is expected to be used as fuel cell vehicles, household energy, and business energy.

  As with other “low-temperature liquefied gas”, the volume of hydrogen is about 1/800 that of “hydrogen gas” when “liquefied hydrogen” is used. Therefore, when supplying the hydrogen produced in the factory to the receiving tank installed at the consumer, like the liquefied oxygen and liquefied nitrogen, the in-vehicle tank is filled with the liquefied hydrogen and conveyed to the consumer. Such a supply form is disclosed in Patent Document 1.

However, transport vehicles for liquefied oxygen and liquefied nitrogen have disadvantages in supplying liquefied hydrogen. This will be described below.
In order to transfer the liquefied hydrogen in the in-vehicle tank to the receiving tank at the consumption destination as liquefied hydrogen, the internal pressure of the in-vehicle tank is increased from the internal pressure of the receiving tank and supplied using the pressure difference. As described above, since the internal pressure of the vehicle-mounted tank is increased at the time of transfer and filling, the internal pressure of the vehicle-mounted tank becomes higher at the time of transfer and filling than at the time of transport.
If the transfer and filling is continued, the internal pressure in the in-vehicle tank will drop and supply due to the pressure difference will not be possible. Therefore, a part of the liquefied hydrogen in the in-vehicle tank is taken out, and heat exchange with the atmosphere is made into hydrogen gas, and this hydrogen gas is returned to the gas phase part (hydrogen gas part) of the in-vehicle tank to increase the internal pressure of the in-vehicle tank. Continue transfer filling. Therefore, at the end of the transfer and filling, the internal pressure of the in-vehicle tank is higher than that during conveyance. Therefore, if liquefied hydrogen remains in the in-vehicle tank even after the completion of the transfer and filling, the liquefied hydrogen is vaporized into hydrogen gas due to heat intrusion from the atmosphere, and the internal pressure of the in-vehicle tank further increases.
For this reason, if the liquefied hydrogen remaining in the in-vehicle tank continues to be supplied to another consumer, the internal pressure of the in-vehicle tank rises above the pressure pressure of the in-vehicle tank during transportation, and the in-vehicle tank may burst if left unattended. . For this reason, it is necessary to release the hydrogen gas in the in-vehicle tank to the atmosphere as needed and to keep the internal pressure of the in-vehicle tank below the withstand pressure while moving to another consumer.

Thus, in order to continue supplying the liquefied hydrogen stored in the vehicle-mounted tank to a plurality of users, hydrogen gas must be released to the atmosphere during the transportation. When released into the atmosphere, when the low-temperature liquefied gas to be stored is liquefied oxygen or liquefied nitrogen, they can be manufactured in large quantities and are inexpensive, so that economic loss due to the release into the atmosphere need not be considered much. However, since hydrogen gas is expensive, releasing it into the atmosphere is a great economic loss.
For this reason, in order to avoid the release of hydrogen gas in the middle of transportation, the current situation is that a large-capacity receiving tank is installed at the consumer, and the liquefied hydrogen loaded in the on-board tank is transferred all at once. The actual situation is the one-drop supply method.
Therefore, the conventional transport vehicle is inconvenient for continuously supplying liquefied hydrogen to a plurality of consumers.
JP 2001-335120 A

  The present invention has been made in view of the above circumstances, and provides a transport vehicle that does not release hydrogen gas in a vehicle tank to the atmosphere even if low temperature liquefied gas is continuously supplied to a plurality of consumers. With the goal.

A transport vehicle according to a first aspect of the present invention is characterized by comprising means for extracting and storing a gas phase gas in an in-vehicle tank, and means for returning the gas stored by the means to the in-vehicle tank.
A transport vehicle according to a second aspect of the present invention includes a booster that pressurizes gas vaporized in a vehicle tank, an auxiliary tank that stores gas pressurized by the booster, the vehicle tank, the booster, and the auxiliary tank. The chassis is provided with a pipe that connects and circulates the vaporized gas by connecting the auxiliary tank and the in-vehicle tank.
According to the transport vehicle of the first and second aspects, the gas phase gas in the on-vehicle tank can be extracted and stored in the auxiliary tank. Therefore, the pressure of the on-vehicle tank can be lowered before the liquefied hydrogen is transferred to the next consumer. Therefore, even if liquefied hydrogen in the in-vehicle tank evaporates due to heat intrusion from the atmosphere during transportation, the pressure in the in-vehicle tank is sufficiently lowered, so that the internal pressure of the in-vehicle tank can be maintained at a pressure within the pressure limit.
Thus, according to the transport vehicle according to claims 1 and 2, since it is not necessary to release hydrogen gas into the atmosphere in the middle of transportation, it is not limited to the conventional one-drop supply method, and economically a plurality of consumptions. Liquid hydrogen can be continuously supplied first.
Furthermore, when transferring the liquefied gas to the receiving tank at the next consumer, the internal pressure of the in-vehicle tank can be raised using the gas stored in the auxiliary tank, so that the liquefied hydrogen in the in-vehicle tank is not evaporated. It is possible to quickly raise the pressure of the on-vehicle tank to a predetermined pressure and provide the liquefied gas smoothly.

A transport vehicle according to a third aspect of the present invention is characterized in that, in the first or second aspect, a first heat exchanger is arranged in a path between the on-vehicle tank and the booster. As the first heat exchanger, a plate fin heat exchanger that performs heat exchange with the atmosphere can be used.
According to the transport vehicle described herein, the hydrogen gas having a temperature of about −250 ° C. in the on-vehicle tank can be increased to a temperature of about −20 ° C. using the first heat exchanger. Therefore, since the room temperature booster using the general material can be used instead of the low temperature booster using the special material, the cost of the booster can be reduced. Moreover, since the room temperature booster is usually lighter than the low temperature booster, the weight of the transport vehicle can be reduced. By using a lightweight booster, the fuel cost for transportation can be reduced.

According to a fourth aspect of the present invention, there is provided the transport vehicle according to the first or second aspect, wherein a second heat exchanger is arranged in a path between the booster and the auxiliary tank. The second heat exchanger can be the same as the first heat exchanger.
According to the transport vehicle of the present description, the hydrogen gas whose temperature has been increased by being pressurized by the booster can be cooled using the second heat exchanger. Therefore, the material of the auxiliary tank can be made from a metal that can withstand high temperatures but is heavy, but can be made of carbon that is weak against high temperatures but lightweight. By using a lightweight auxiliary tank, the fuel cost for transportation can be reduced.

The transport vehicle of the present invention according to claim 5 is characterized in that, in claim 4, a second heat exchanger is arranged in a path between the booster and the auxiliary tank.
According to the transport vehicle described here, a room temperature booster using a general material can be used instead of a low temperature booster using a special material, and the auxiliary tank material can withstand high temperatures but is made of a heavy metal, It is weak against high temperatures but can be made of lightweight carbon. Therefore, the weight of the transport vehicle can be further reduced, and the fuel cost for transportation can be further reduced.

The transport vehicle of the present invention according to claim 6 is characterized in that, in claim 5, the first heat exchanger and the second heat exchanger are integrally formed to form a third heat exchanger.
According to the transport vehicle described herein, the third heat exchanger can not only exchange heat with the atmosphere, but also exchange heat between the low-temperature gas from the vehicle tank and the high-temperature gas discharged from the booster. , Heat exchange efficiency can be increased.

According to a seventh aspect of the present invention, there is provided a transport vehicle according to the sixth aspect, wherein the temperature controller is provided on a path between the third heat exchanger and the booster and a path between the third heat exchanger and the auxiliary tank. It is characterized by being arranged.
According to the transport vehicle of the present description, when the temperature of the gas leaving the third heat exchanger and introduced into the booster is too low, the temperature controller provided in the path between the third heat exchanger and the booster Can be heated to an appropriate temperature. Also, if the temperature of the gas leaving the third heat exchanger and introduced into the auxiliary tank is too high, it is cooled to an appropriate temperature by a temperature controller provided in the path between the third heat exchanger and the auxiliary tank. it can. This eliminates adverse effects on the booster and auxiliary tank.

According to an eighth aspect of the present invention, there is provided the transport vehicle according to the sixth or seventh aspect, wherein a heater is disposed in a path between the onboard tank and the third heat exchanger.
According to the transport vehicle described herein, when the third heat exchanger is out of design conditions and the temperature of the gas exiting the third heat exchanger and introduced into the booster or auxiliary tank is too low, Since the temperature of the hydrogen gas from the tank can be raised using a heater, the booster and the auxiliary tank are not adversely affected.

The transport vehicle according to the present invention includes means for extracting and storing the gas-phase portion gas in the vehicle-mounted tank, and means for returning the gas stored by the means to the vehicle-mounted tank.
According to such a configuration, it is not necessary to release hydrogen gas to the atmosphere in the middle of conveyance, so that it is not limited to the conventional one-drop supply method, and liquefied hydrogen can be supplied economically to a plurality of consumers.
Such an effect of not releasing into the atmosphere is effective in the case of transporting liquefied oxygen or liquefied nitrogen, but is particularly effective for transporting liquefied hydrogen. In general, it is particularly effective when the release of air during transportation, such as liquefied hydrogen or liquefied helium, has a large economic loss.

  Hereinafter, the present invention will be described in detail with reference to the drawings. However, the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

  FIG. 1 is a transport vehicle according to a first embodiment of the present invention. FIG. 1A is a schematic diagram of the transport vehicle, and shows a state in which a low-temperature liquefied gas L is filled in an in-vehicle tank 1. FIG. 1B is a schematic configuration diagram illustrating a supply device 10 including an in-vehicle tank 1, a booster 2, an auxiliary tank 3, and a pipeline 4.

Connecting the booster 2 for extracting and pressurizing the gas phase gas in the in-vehicle tank 1, the auxiliary tank 3 for storing the gas pressurized by the booster 2, the in-vehicle tank 1, the booster 2 and the auxiliary tank 3, and A pipeline 4 for connecting the auxiliary tank 3 and the vehicle-mounted tank 1 to circulate the vaporized gas is provided in the chassis 9 of the transport vehicle.
Each will be described in detail below.

The in-vehicle tank 1 is a storage tank that stores liquefied hydrogen produced in a factory. The material of the in-vehicle tank 1 is appropriately designed according to the temperature and pressure of hydrogen stored. Withstand voltage performance, for example 0.3MPa～1.3MPa, the internal volume is, for example, ^{15 m} 3 to 20 m ^3.
The following equipment is attached to the vehicle-mounted tank 1.
a. Pipelines and valves for transferring and filling liquefied hydrogen into the receiving tank of the consumer.
b. Pipelines and valves for releasing gas phase gas to the atmosphere when the internal pressure of the onboard tank 1 rises.
c. A heat exchanger, a conduit, and a valve for taking out a part of the liquefied hydrogen in the in-vehicle tank 1 to the outside, evaporating it by exchanging heat with the atmosphere, and returning the vaporized hydrogen gas to the gas phase part of the in-vehicle tank 1.
Although a to c are not shown, they are also attached to an on-vehicle tank for low-temperature liquefied gas other than liquefied hydrogen.

The booster 2 is a compressor that extracts and pressurizes gas phase gas in the in-vehicle tank 1 and stores the gas in the auxiliary tank 3. For example, the suction pressure is 0.2MPa～0.3MPa, discharge pressure 0.5MPa～1.5MPa, discharge temperature is 90 ° C. to 100 ° C., the processing content is set to 20Nm ³ / h~30Nm ³ / h. Since the hydrogen gas in the on-vehicle tank 1 is very low, for example, −180 ° C. to −250 ° C., the booster 2 having durability at low temperatures is used.

Auxiliary tank 3 is for enclosing a pressurized hydrogen gas booster 2, the internal volume is, for example, 2m ³ ~4m ^3. Since the temperature of the hydrogen gas from the booster 2 is as high as 90 ° C. to 100 ° C., a material that can withstand the high temperature, for example, metal is used.

  The vehicle-mounted tank 1, the booster 2, and the auxiliary tank 3 are connected by a pipeline 4 in order. Further, the auxiliary tank 3 and the vehicle-mounted tank 1 are also connected by a conduit 4. Thereby, the hydrogen gas sealed in the auxiliary tank 3 can be supplied to the gas phase portion of the in-vehicle tank 1. The pipe 4 is appropriately provided with a valve α capable of stopping the gas flow.

Next, the transfer of liquefied hydrogen by the transport vehicle of the present invention will be described.
The transport vehicle storing the liquefied hydrogen arrives at the first consumer (which is also the first supplier when viewed from the transport side), and then transfers the liquefied hydrogen into the receiving tank at the consumer.
Specifically, after the liquefied hydrogen take-off valve (not shown) provided in the pipeline 4 and the liquefied hydrogen take-in valve (not shown) of the receiving tank are connected by a hose, the liquefied hydrogen in the in-vehicle tank 1 is received by the receiving tank. Transfer and fill in a liquid state.
As the liquefied hydrogen in the in-vehicle tank 1 is filled in the receiving tank, the internal pressure of the in-vehicle tank 1 decreases, and the transfer / filling amount per unit time decreases. For this reason, a part of the liquefied hydrogen in the in-vehicle tank 1 is taken out to the outside through the pipe line 4 and heat-exchanged with the atmosphere to increase the volume as hydrogen gas, and the hydrogen gas is returned to the gas phase part in the in-vehicle tank 1. Then, increase the pressure of the in-vehicle tank 1 and continue the transfer and filling.
In this way, the internal pressure of the in-vehicle tank 1 is higher at the end of transfer and filling of liquefied hydrogen than at the time of transport. When the transport vehicle moves to the second consumer in this state, liquefied hydrogen in the in-vehicle tank 1 is vaporized due to heat intrusion from the atmosphere during the movement, and the internal pressure of the in-vehicle tank 1 increases. Therefore, the valve (safety valve) provided in the pipe line 4 is sometimes opened, and it is necessary to release the hydrogen gas in the in-vehicle tank 1 to the atmosphere to keep the internal pressure of the in-vehicle tank 1 below the pressure resistance performance.

On the other hand, in the transport vehicle of the present invention, after completion of the transfer and filling, the booster 2 is operated to extract the hydrogen gas in the in-vehicle tank 1 and store it in the auxiliary tank 3. By extracting the hydrogen gas from the in-vehicle tank 1, the internal pressure in the in-vehicle tank 1 decreases.
When the internal pressure in the in-vehicle tank 1 is lowered and the transport vehicle goes to the second consumer, even if the liquefied hydrogen in the in-vehicle tank 1 is vaporized due to heat penetration from the atmosphere during movement, the in-vehicle tank 1 The internal pressure can be maintained at a pressure lower than the pressure resistance.

  The transport vehicle arrives at the second consumption destination, and in order to transfer and fill liquefied hydrogen into the receiving tank there, the same procedure as the first consumption destination is followed. However, in this case, the internal pressure of the in-vehicle tank 1 is reduced. On the other hand, the internal pressure of the in-vehicle tank 1 can be increased by supplying hydrogen gas in the auxiliary tank 3. The operation of taking out a part of the liquefied hydrogen in the in-vehicle tank 1 and obtaining hydrogen gas by heat exchange with the atmosphere may be performed after the pressure increase in the auxiliary tank 3 is completed, and transfer and filling are performed quickly. be able to. In addition, the vaporization of hydrogen gas accompanying the movement from the first consumer to the second consumer has the advantage that it can be used without waste for transfer and filling at the second consumer.

  FIG. 2 is a transport vehicle according to a second embodiment of the present invention, and the same components as those in FIG. 1 are given the same numbers (the same applies hereinafter). The present embodiment differs from FIG. 1 in that a first heat exchanger 25 is provided between the in-vehicle tank 1 and the booster 2.

  The first heat exchanger 25 increases the temperature by exchanging hydrogen from the vehicle tank 1 with the atmosphere and is, for example, a plate fin heat exchanger. As the heating source, the atmosphere is usually simple, but it is also possible to use warm water (higher than the atmosphere) of the radiator of the transport vehicle.

  When the low-temperature hydrogen from the in-vehicle tank 1 passes through the first heat exchanger 25 and is raised to around −20 ° C., the booster 2 is the low-temperature booster 2 using the special material of the first embodiment. It can replace with and can use the booster 2 for room temperature using a general raw material. The room temperature booster 2 is cheaper and more economical than the low temperature booster 2. Further, since the room temperature booster 2 is lighter than the low temperature booster 2, the weight of the transport vehicle is reduced, and the fuel cost for transportation can be reduced.

  FIG. 3 is a transport vehicle according to a third embodiment of the present invention, and this embodiment is different from FIG. 2 in that a second heat exchanger 36 is provided between the booster 2 and the auxiliary tank 3. is there.

The structure of the second heat exchanger 36 is the same as that of the first heat exchanger 25, but the function is different.
The 2nd heat exchanger 36 cools 90 degreeC-100 degreeC high temperature hydrogen gas discharged from the booster 2 to about room temperature. The auxiliary tank 3 needs to be made of metal so that it can withstand high temperatures when high-temperature hydrogen gas is introduced. However, if the temperature of the hydrogen gas is 80 ° C. or less, a plastic material such as carbon can be used.

  In this embodiment, the auxiliary tank 3 can be changed from a heavy metal auxiliary tank 3 to a lightweight carbon auxiliary tank 3 by lowering the temperature of the introduced hydrogen gas. By making the auxiliary tank 3 lighter, the weight of the transport vehicle can be reduced and the fuel cost and other costs can be reduced.

  FIG. 4 is a transport vehicle according to a fourth embodiment of the present invention. This embodiment is different from FIG. 3 in that a first heat exchanger 25 is provided between the in-vehicle tank 1 and the booster 2. It is.

  In this embodiment, by using the first heat exchanger 25 and the second heat exchanger 36, a room temperature booster 2 using a general material is used instead of a low temperature booster 2 using a special material. In addition, the heavy metal auxiliary tank 3 can be changed to a lightweight carbon auxiliary tank 3. Therefore, the weight of the vehicle body of the transport vehicle can be further reduced, and costs such as fuel costs can be further suppressed.

  FIG. 5 is a transport vehicle according to a fifth embodiment of the present invention. This embodiment is different from FIG. 4 in that the function of the first heat exchanger and the function of the second heat exchanger are integrated. The three heat exchanger 47 is provided.

  According to the present embodiment, the low-temperature hydrogen gas from the in-vehicle tank 1 is heat-exchanged with the high-temperature gas discharged from the room temperature booster 2, so that the first heat exchanger and the second heat exchanger alone Compared to heat exchange with the atmosphere, the heat exchange efficiency is increased, and the third heat exchanger 47 is smaller and lighter than the first heat exchanger and the second heat exchanger.

  FIG. 6 is a transport vehicle according to a sixth embodiment of the present invention. This embodiment differs from FIG. 5 in that the first temperature is in the path between the third heat exchanger 47 and the room temperature booster 2. In addition to providing the adjuster 58, the second temperature adjuster 59 is provided in the path between the third heat exchanger 47 and the lightweight auxiliary tank 3.

The third heat exchanger 47 is designed by performing a predetermined calculation based on the low-temperature hydrogen gas from the vehicle-mounted tank 1 and the high-temperature hydrogen gas from the room temperature booster 2, but the design value depends on the weather and season. There is also a possibility of deviating from.
The first temperature controller 58 leads out the third heat exchanger 47 and exchanges heat of the hydrogen gas directed to the room temperature booster 2 with the atmosphere, and is similar in structure to the first heat exchanger 25.
The first temperature controller 58 can adjust the temperature of the hydrogen gas leading out from the third heat exchanger 47 to a temperature suitable for the room temperature booster 2 both when it is too high and when it is too low.

The second temperature controller 59 leads out the third heat exchanger 47 and exchanges heat of the hydrogen gas directed to the lightweight auxiliary tank 3 with the atmosphere, and has the same structure as the first heat exchanger 25.
With the second temperature controller 59, the temperature of the hydrogen gas leading out from the third heat exchanger 47 can be adjusted to a temperature suitable for the lightweight auxiliary tank 3 both when it is too high and when it is too low.

  FIG. 7 shows a transport vehicle according to a seventh embodiment of the present invention. This embodiment differs from FIG. 6 in that a heater 65 is provided between the in-vehicle tank 1 and the third heat exchanger 47. In the point. The structure of the heater 65 is the same as that of the first heat exchanger 25. In addition, the 1st temperature controller 58 and the 2nd temperature controller 59 in FIG. 7 are provided as needed.

  The warmer 65 preheats the hydrogen gas in the in-vehicle tank 1 before introducing it into the third heat exchanger 47. If the third heat exchanger 47 is in a use state that deviates from the design condition and the gas evaporated in the in-vehicle tank 1 is not sufficiently heated, the temperature of the gas discharged from the room temperature booster 2 decreases. There is a risk of it. In this case, the gas evaporated in the in-vehicle tank 1 cannot be sufficiently heated by the third heat exchanger 47, and the temperature of the gas is further lowered. Since the room temperature booster 2 and the lightweight auxiliary tank 3 are not for low temperatures, they may be damaged. Therefore, the warmer 68 is disposed between the vehicle-mounted tank 1 and the third heat exchanger 47 and warms the gas in advance, thereby adversely affecting the room temperature booster 2 and the lightweight auxiliary tank 3. Can be suppressed.

  To provide a method for providing low-temperature liquefied gas that is highly economical and convenient in various industrial fields using low-temperature liquefied gas, such as petroleum industry, chemical industry, semiconductor industry, glass industry, metal industry, and automobile industry. it can.

It is the figure which showed typically an example of the transport vehicle which concerns on 1st Embodiment of this invention. It is a schematic block diagram which shows typically an example of the liquefied gas supply apparatus mounted in the liquefied gas transport vehicle which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which shows typically an example of the liquefied gas supply apparatus mounted in the transport vehicle which concerns on 3rd Embodiment of this invention. It is a schematic block diagram which shows typically an example of the liquefied gas supply apparatus mounted in the transport vehicle which concerns on 4th Embodiment of this invention. It is a schematic block diagram which shows typically an example of the liquefied gas supply apparatus mounted in the transport vehicle which concerns on 5th Embodiment of this invention. It is a schematic block diagram which shows typically an example of the liquefied gas supply apparatus mounted in the transport vehicle which concerns on 6th Embodiment of this invention. It is a schematic block diagram which shows typically an example of the liquefied gas supply apparatus mounted in the transport vehicle which concerns on 7th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Car tank, 2 Booster, 3 Auxiliary tank, 4 Pipe line, 25 1st heat exchanger, 36 2nd heat exchanger, 47 3rd heat exchanger, 58 1st temperature controller, 59 2nd temperature controller, 65 Heater, 9 chassis, α valve, L Low temperature liquefied gas.

Claims (8)

  A low-temperature liquefied gas transport vehicle comprising means for extracting and storing gas phase portion gas in an in-vehicle tank and means for returning the gas stored by the means to the in-vehicle tank.   A booster that extracts and pressurizes gas phase gas in an in-vehicle tank, an auxiliary tank that stores gas pressurized by the booster, the in-vehicle tank, the booster, and the auxiliary tank are connected, and the auxiliary tank A low-temperature liquefied gas transport vehicle, characterized in that a chassis is provided with a conduit for connecting the vehicle-mounted tank and circulating the gas-phase gas.   The low-temperature liquefied gas transport vehicle according to claim 1 or 2, wherein a first heat exchanger is arranged in a path between the on-vehicle tank and the booster.   The low-temperature liquefied gas transport vehicle according to claim 1 or 2, wherein a second heat exchanger is arranged in a path between the booster and the auxiliary tank.   The low-temperature liquefied gas transport vehicle according to claim 3, wherein a second heat exchanger is arranged in a path between the booster and the auxiliary tank.   The low-temperature liquefied gas transport vehicle according to claim 5, wherein the first heat exchanger and the second heat exchanger are integrally formed to form a third heat exchanger.   The low temperature according to claim 6, wherein a temperature controller is arranged in a path between the third heat exchanger and the booster and in a path between the third heat exchanger and the auxiliary tank. Liquefied gas transport vehicle.   The low-temperature liquefied gas transport vehicle according to claim 6 or 7, wherein a heater is disposed in a path between the on-vehicle tank and the third heat exchanger.

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