JP6946246B2 - LNG saturated liquid supply device - Google Patents

Description

The present invention relates to an LNG saturated liquid supply device for supplying liquefied natural gas (LNG) as an LNG saturated liquid in a state in which it is easily vaporized.

Natural gas vehicles, which contain less harmful substances in exhaust gas, have begun to spread. CNG vehicles that use compressed natural gas (CNG) are the first natural gas vehicles. LNG vehicles that use liquefied natural gas (LNG) and have the same volume of tanks to extend the mileage up to about three times and are suitable for long-distance transportation have also begun to be supplied.

To run a natural gas vehicle, you need a natural gas station that fuels the natural gas vehicle. For CNG vehicles, a CNG stand that supplies CNG will be installed. For LNG vehicles, an LNG stand that supplies LNG is required.

As the LNG supplied to the LNG vehicle, the LNG is supplied as an LNG saturated liquid adjusted to a uniform temperature at which it is easy to vaporize. This is because an LNG vehicle does not have a pressurizing device for an LNG tank, so that in an extremely low temperature LNG, when the LNG is consumed by running, the LNG cannot be taken out from the LNG tank.

Therefore, in the LNG stand, it is necessary to prepare an LNG saturated liquid from the cryogenic LNG in advance and fill the vehicle with the LNG saturated liquid through a dispenser.
In order to prepare an LNG saturated liquid, it is necessary to heat LNG originally at about -155 ° C. to about -128 ° C. (equivalent to 0.8 MPa).

At present, in Japan, the number of LNG stands for vehicles is extremely small, and there are only those that are attached to the CNG stands that are in practical use.
At the LNG stand attached to the CNG stand, natural gas derived from CNG is mixed with LNG to heat it, and an LNG saturated liquid can be obtained relatively easily.

However, if LNG vehicles become widespread in the future, a large number of LNG stations will be required to fill the vehicles with LNG saturated liquid. At this time, the LNG stand cannot always be attached to the CNG stand.
As LNG vehicles become more widespread, the demand for LNG stands will increase, and stand-alone type LNG stands that are not attached to CNG stands will be required.
Then, in an environment where natural gas derived from CNG does not exist, a technique for appropriately raising the temperature of LNG to obtain an LNG saturated liquid is required.

As a prior art document relating to such an LNG saturated liquid supply device, the applicant has grasped the following Patent Document 1.

International Publication No. 2011/152965 Pamphlet

The above-mentioned Patent Document 1 relates to a "liquefied natural gas supply system" and has the following description (translation by the applicant).
[0028]
In one embodiment detailed in FIG. 1, an LNG distribution system is shown. The bulk storage tank A is maintained at pressure P1 by a standard tank pressure control method (not shown). The pressure P1 may change somewhat over time to minimize unnecessary aeration of the natural gas vapor. The pressure of a typical bulk storage tank is about 4-12 barg. Liquefied natural gas exits bulk storage tank A through line 1 and pump B. The liquefied natural gas having a pressure P2 higher than the pressure P1 passes through the valve V1 by the line V1 and enters the condenser C having a heat transfer relationship together with the conditioning container C1. The liquefied natural gas exits the condenser C through line 4 at a pressure P2 at a temperature higher than the temperature before entering the condenser C. This outlet temperature supplies a slightly colder natural gas at pressure P1 that is substantially equal to the saturation temperature.
[0029]
Both natural gas and liquefied natural gas are contained inside the conditioning container C1. The liquefied natural gas from line 2 enters the condenser C, and the vapor of the condenser C condenses to form a liquid. The condensed liquid is supplied to the heating element D through line 5, where it evaporates and is supplied to line 6, where it is supplied to the liquefied natural gas bulk storage tank A and the conditioning vessel C1. Suitable heating elements include peripheral vaporizers and electric or steam vaporizers well known in the art. Line 6 ensures that the pressure in the conditioning vessel C1 remains substantially at pressure P1. The gas produced by the heating element D replaces the gas condensed in the conditioning vessel C1 on time average.

In Patent Document 1, the liquefied natural gas stored in the bulk storage tank A is sent to the condenser C in the conditioning container C1 to be made into an LNG saturated liquid and supplied from a dispenser (not shown) connected to the line 4. do.
In such a structure, the conditioning container C1, the condenser C, and the dispenser are arranged in one system to form one LNG saturated liquid supply line. Therefore, in order to supply the LNG saturated liquid to a plurality of vehicles at the same time, it is necessary to prepare a plurality of systems of the conditioning container C1, the condenser C, and the dispenser. Therefore, the larger the scale of the LNG saturated liquid supply facility, the larger the number of sets of the conditioning container C1, the condenser C, and the dispenser must be prepared, and the equipment efficiency becomes very poor.

〔Purpose〕
The present invention has been made with the following object in order to solve the above problems.
Provided is an LNG saturated liquid supply device that improves equipment efficiency and is advantageous for increasing the scale of the supply facility.

The LNG saturated liquid supply device according to claim 1 employs the following configuration in order to achieve the above object.
LNG receiving route and
A heat exchanger that heats the LNG received in the above LNG receiving path by heat exchange with a heating gas to make it an LNG saturated liquid.
An LNG saturated liquid storage tank for storing the LNG saturated liquid obtained in the heat exchanger, and an LNG saturated liquid storage tank.
One or more LNG saturated liquid delivery paths for supplying the LNG saturated liquid stored in the LNG saturated liquid storage tank, and
A heating circuit for taking out the liquefied heating gas condensed and liquefied by the heat exchanger, heating it, and returning it to the heat exchanger as the heating gas again.
The upper boil-off gas space of the LNG saturated liquid storage tank is communicated with the heat exchanger, and a heating gas supply unit for supplying the boil-off gas as the heating gas to the heat exchanger is provided.

The LNG saturated liquid supply device according to claim 2 employs the following configuration in addition to the configuration according to claim 1.
A first LNG pump for boosting LNG received from the LNG transport means is provided in the LNG receiving path.

The LNG saturated liquid supply device according to claim 3 employs the following configuration in addition to the configuration according to claim 1 or 2.
A second LNG pump for boosting the LNG saturated liquid is provided in the LNG saturated liquid delivery path.

The LNG saturated liquid supply device according to claim 4 employs the following configuration in addition to the configuration according to any one of claims 1 to 3.
The heat exchanger is provided in the upper boil-off gas space of the LNG saturated liquid storage tank.

The LNG saturated liquid supply device according to claim 5 employs the following configuration in addition to the configuration according to any one of claims 2 to 4.
The LNG receiving path is provided with an LNG receiving tank that temporarily stores LNG received from the LNG transport means before it is introduced into the first LNG pump.

The LNG saturated liquid supply device according to claim 1 receives LNG in the LNG receiving path. The LNG accepted here is, for example, supercooled LNG. The LNG received in the LNG receiving path is heated by heat exchange with a heating gas in a heat exchanger to be made into an LNG saturated liquid. The LNG saturated liquid obtained by the heat exchanger is stored in the LNG saturated liquid storage tank. The LNG saturated liquid stored in the LNG saturated liquid storage tank is supplied by the LNG saturated liquid delivery path. The heat exchanger is provided with a heating circuit. The heating circuit takes out the liquefied heating gas condensed and liquefied by the heat exchanger, heats it, and returns it to the heat exchanger as a heating gas again. Further, the upper boil-off gas space of the LNG saturated liquid storage tank and the heat exchanger are communicated with each other by the heating gas supply unit. The heating gas supply unit supplies boil-off gas as heating gas to the heat exchanger.
The LNG saturated liquid supply device according to claim 1 temporarily stores the LNG saturated liquid obtained by heating with a heat exchanger in the LNG saturated liquid storage tank, and supplies the LNG saturated liquid as needed. Offer by. If the scale of the supply facility is small, one LNG saturated liquid delivery path may be connected to the LNG saturated liquid storage tank. When increasing the scale of the supply facility, two or more LNG saturated liquid delivery channels are connected to the LNG saturated liquid storage tank. Also at this time, one set of heat exchanger and heating circuit is sufficient for one LNG saturated liquid storage tank. In this way, the equipment efficiency is much higher than that of the conventional equipment, which is advantageous for increasing the scale of the supply facility.
Further, since the LNG saturated liquid stored in the LNG saturated liquid storage tank is supplied as needed, it is possible to cope with a sudden change in the demand for the LNG saturated liquid.

In the LNG saturated liquid supply device according to claim 2, the LNG received from the LNG transport means is boosted by the first LNG pump provided in the LNG receiving path and introduced into the heat exchanger.
Therefore, the low-pressure supercooled LNG received from the LNG transport means is boosted to a predetermined pressure to become an LNG saturated liquid, which is stored in the LNG saturated liquid storage tank. Therefore, due to the action of the predetermined pressure, the LNG saturated liquid is smoothly delivered from the LNG saturated liquid storage tank to the LNG saturated liquid delivery path.

In the LNG saturated liquid supply device according to claim 3, the LNG saturated liquid in the LNG saturated liquid storage tank is boosted by the second LNG pump and sent to the LNG saturated liquid delivery path.
Therefore, the LNG saturated liquid in the LNG saturated liquid storage tank is fed at a predetermined pressure, and the LNG saturated liquid is smoothly supplied.

The LNG saturated liquid supply device according to claim 4 is provided with the heat exchanger in the upper boil-off gas space of the LNG saturated liquid storage tank.
In this structure, the heating gas supply unit can be changed from, for example, a piping structure to an opening structure. In other words, equipment can be omitted by the amount of piping, and equipment efficiency is further improved. Further, since the heat exchanger is housed in the LNG saturated liquid storage tank, there are few devices arranged around the tank, and the space around the tank is arranged.

In the LNG saturated liquid supply device according to claim 5, the LNG received from the LNG transport means is temporarily stored in the LNG receiving tank. The LNG in the LNG receiving tank is boosted by the first LNG pump and introduced into the heat exchanger.
Therefore, even if there is a sudden change in the LNG receiving cycle by the LNG transport means and it takes time to receive the next LNG transport means, the LNG stored in the LNG receiving tank can be used.

It is a block diagram explaining the 1st Embodiment of the LNG saturated liquid supply apparatus of this invention. It is a block diagram explaining the 2nd Embodiment of the LNG saturated liquid supply apparatus of this invention. It is a block diagram explaining the 3rd Embodiment of the LNG saturated liquid supply apparatus of this invention.

Next, a mode for carrying out the present invention will be described.

◆ First Embodiment FIG. 1 is a first embodiment showing an LNG saturated liquid supply device to which the present invention is applied.

[Overall structure]
The LNG saturated liquid supply device of the first embodiment includes an LNG receiving path 10, a heat exchanger 20, a heating circuit 30, an LNG saturated liquid storage tank 40, an LNG saturated liquid delivery path 50, and a heating gas. The supply unit 60 is provided.

The LNG receiving route 10 receives LNG from LNG lorry 1, which is a form of LNG transportation means.
The LNG received in the LNG receiving path 10 is a supercooled and low-pressure LNG. Examples of the supercooled and low-pressure LNG include those having a temperature of -155 ° C. and a pressure of about 0.3 MPaG.

The heat exchanger 20 heats the supercooled LNG received in the LNG receiving path 10 by heat exchange with a heating gas to obtain an LNG saturated liquid.
The LNG saturated liquid is LNG in a saturated state, in which LNG reaches the boiling point or its vicinity, and LNG and NG coexist in a stable and balanced equilibrium state in the system. Examples of the LNG saturated liquid include those having a temperature of -126.4 ° C. and a pressure of about 0.8 MPaG.
The LNG saturated liquid heated by the heat exchanger 20 is stored in the LNG saturated liquid storage tank 40 through the LNG saturated liquid passage 21.

As the heating gas in the heat exchanger 20, the boil-off gas of the LNG saturated liquid storage tank 40 is used as described later.

The LNG saturated liquid storage tank 40 stores the LNG saturated liquid obtained by the heat exchanger 20.
As the LNG saturated liquid storage tank 40, for example, a tank having a double-shell structure having a vacuum insulation space can be used.
As described above, the LNG saturated liquid can be stored at a temperature of -126.4 ° C. and a pressure of about 0.8 MPaG.
Therefore, it is preferable to use the LNG saturated liquid storage tank 40 having a pressure-resistant structure that can sufficiently withstand an internal pressure of about 0.8 MPaG.

The LNG saturated liquid delivery path 50 supplies the LNG saturated liquid stored in the LNG saturated liquid storage tank 40. In the figure, an example in which one LNG saturated liquid delivery path 50 is provided is shown, but the LNG saturated liquid delivery path 50 may be provided in two or more. In this case, a pressurizing mechanism that pressurizes with a pressurizing capacity commensurate with the filling amount is required. The LNG saturated liquid delivery path 50 may be provided with a dispenser 52 for filling an LNG vehicle with saturated LNG. The dispenser 52 may be adapted to the supply target of saturated LNG.

The heating gas supply unit 60 is a communication passage that connects the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40 and the heat exchanger 20. The heating gas supply unit 60 supplies the boil-off gas existing in the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40 to the heat exchanger 20 as the heating gas.

The heating circuit 30 takes out the liquefied heating gas condensed and liquefied by the heat exchanger 20 to heat it, and returns it to the heat exchanger 20 as a heating gas again.
The heating circuit 30 includes a liquefied gas passage 31, an evaporator 32, and an evaporative gas passage 33. The liquefied gas passage 31 takes out the liquefied heating gas condensed and liquefied by the heat exchanger 20 from the heat exchanger 20. The evaporator 32 evaporates the liquefied heating gas taken out in the liquefied gas passage 31 to make it a heating gas again. The evaporative gas passage 33 returns the heated gas vaporized by the evaporator 32 to the heat exchanger 20 again.
As the evaporator 32, for example, one having a heating fin for heating by atmospheric heat can be used. As the heat source of the evaporator 32, not only atmospheric heat but also combustion heat, electric heat, hot water and the like can be used.

Since the heating gas supply unit 60 communicates the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40 with the heat exchanger 20, the LNG saturated liquid storage tank 40 and the heat exchanger 20 communicate with each other. It is kept at a uniform pressure. For example, if the LNG saturated liquid storage tank 40 stores the LNG saturated liquid having a temperature of -126.4 ° C and a pressure of 0.8 MPaG, the heat exchanger 20 has a temperature of -126.4 ° C and a pressure of 0. The 8 MPaG LNG saturated liquid is refluxed.

The LNG receiving path 10 is provided with a first LNG pump 11 that boosts the LNG received from the LNG lorry 1.
The first LNG pump 11 boosts the supercooled and low-pressure LNG (for example, temperature-155 ° C., 0.3 MPaG) received from the LNG lorry 1, and the supercooled LNG (for example, temperature-155 ° C., 1.0 MPaG). ).

The LNG saturated liquid delivery path 50 is provided with a second LNG pump 51 that boosts the LNG saturated liquid.
The second LNG pump 51 boosts the LNG saturated liquid (for example, temperature -126.4 ° C., pressure 0.8 MPaG) taken out from the LNG saturated liquid storage tank 40 to a pressure sufficient to fill the LNG vehicle from the dispenser 52. do.

[Effect of the first embodiment]
The first embodiment has the following effects.

In the first embodiment, LNG is received in the LNG receiving path 10. The LNG accepted here is, for example, supercooled LNG. The LNG received in the LNG receiving path 10 is heated by heat exchange with the heating gas in the heat exchanger 20 to be made into an LNG saturated liquid. The LNG saturated liquid obtained in the heat exchanger 20 is stored in the LNG saturated liquid storage tank 40. The LNG saturated liquid stored in the LNG saturated liquid storage tank 40 is supplied by the LNG saturated liquid delivery path 50. The heat exchanger 20 is provided with a heating circuit 30. The heating circuit 30 takes out the liquefied heating gas condensed and liquefied by the heat exchanger 20 to heat it, and returns it to the heat exchanger 20 as a heating gas again. Further, the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40 and the heat exchanger 20 are communicated with each other by the heating gas supply unit 60. The heating gas supply unit 60 supplies boil-off gas as heating gas to the heat exchanger 20.
In the first embodiment, the LNG saturated liquid obtained by heating with the heat exchanger 20 is temporarily stored in the LNG saturated liquid storage tank 40, and is supplied through the LNG saturated liquid supply path 50 as needed. .. If the scale of the supply facility is small, one LNG saturated liquid delivery path 50 may be connected to the LNG saturated liquid storage tank 40. When increasing the scale of the supply facility, two or more LNG saturated liquid delivery paths 50 are connected to the LNG saturated liquid storage tank 40. Also at this time, one set of the heat exchanger 20 and the heating circuit 30 is sufficient for one LNG saturated liquid storage tank 40. In this way, the equipment efficiency is much higher than that of the conventional equipment, which is advantageous for increasing the scale of the supply facility.
Further, since the LNG saturated liquid stored in the LNG saturated liquid storage tank 40 is supplied as needed, it is possible to cope with a sudden change in the demand for the LNG saturated liquid.

In the first embodiment, the LNG received from the LNG lorry 1 is boosted by the first LNG pump 11 provided in the LNG receiving path 10 and introduced into the heat exchanger 20.
Therefore, the low-pressure supercooled LNG received from the LNG lorry 1 becomes an LNG saturated liquid having a predetermined pressure and temperature, and is stored in the LNG saturated liquid storage tank 40. Therefore, due to the action of the predetermined pressure, the LNG saturated liquid is smoothly supplied from the LNG saturated liquid storage tank 40 to the LNG saturated liquid delivery path 50.

In the first embodiment, the LNG saturated liquid in the LNG saturated liquid storage tank 40 is boosted by the second LNG pump 51 and sent to the LNG saturated liquid delivery path 50.
Therefore, the LNG saturated liquid in the LNG saturated liquid storage tank 40 is fed at a predetermined pressure, and the LNG saturated liquid is smoothly supplied.

Second Embodiment FIG. 2 is a second embodiment of the LNG saturated liquid supply device to which the present invention is applied.

In the second embodiment, the heat exchanger 20 is provided in the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40.

Therefore, the heating gas supply unit 60 in this example is provided as an opening in the upper part of the heat exchanger 20 instead of the continuous passage as in the first embodiment. The opening functions as a heating gas supply unit 60, and the boil-off gas existing in the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40 is supplied to the heat exchanger 20 as a heating gas.

The downstream side of the LNG receiving path 10 is connected to the lower side of the heat exchanger 20 through the vacuum insulation space of the LNG saturated liquid storage tank 40. The LNG saturated liquid heated by the heat exchanger 20 is stored in the LNG saturated liquid storage tank 40 through the LNG saturated liquid passage 21.

Further, the heating circuit 30 in this example takes out the liquefied gas from the liquefied gas passage 31 connected to the lower side of the heat exchanger 20 and liquefies it by the evaporator 32 provided outside the LNG saturated liquid storage tank 40. Evaporate the gas. The heated gas evaporated by the evaporator 32 is passed through the upper boil-off gas space 41 and the heated gas supply unit 60 by the evaporation gas passage 33 connected to the upper boil-off gas space 41 of the LNG saturated liquid storage tank 40. It is returned to the evaporator 20.
Other than that, it is the same as that of the first embodiment, and the same reference numerals are given to the same parts.

[Effect of the second embodiment]
The second embodiment has the following effects.

In the second embodiment, the heat exchanger 20 is provided in the upper boil-off gas space of the LNG saturated liquid storage tank.
In this structure, the heating gas supply unit 60 can be changed from, for example, a piping structure to an opening structure. In other words, equipment can be omitted by the amount of piping, and equipment efficiency is further improved. Further, since the heat exchanger 20 is housed in the LNG saturated liquid storage tank 40, there are few devices arranged around the tank, and the space around the tank is arranged.
Other than that, the second embodiment also has the same effect as that of the first embodiment.

3. Third Embodiment FIG. 3 is a third embodiment of an LNG saturated liquid supply device to which the present invention is applied.

The third embodiment includes an LNG receiving tank 70 in the LNG receiving path 10 for temporarily storing the LNG received from the LNG lorry 1 before introducing it into the first LNG pump 11.
The LNG receiving tank 70 is provided with a cooling line 71 for introducing a part of the LNG received from the LNG lorry 1 into the boil-off gas space above the LNG receiving tank 70 and cooling the boil-off gas.
Other than that, it is the same as that of the first embodiment, and the same reference numerals are given to the same parts.

[Effect of Third Embodiment]
The third embodiment has the following effects.

In the third embodiment, the LNG received from the LNG lorry 1 is temporarily stored in the LNG receiving tank 70. The LNG of the LNG receiving tank 70 is boosted by the first LNG pump 11 and introduced into the heat exchanger 20.
Therefore, even if there is a sudden change in the LNG receiving cycle by the LNG lorry 1 and it takes time to receive the next LNG lorry 1, the LNG stored in the LNG receiving tank 70 can handle the situation.
Other than that, the third embodiment also has the same effect as that of the first embodiment.

Other Modifications Although the particularly preferred embodiments of the present invention have been described above, the present invention is not limited to the illustrated embodiments and can be modified into various embodiments, and the present invention is various. The purpose is to include a modified example of.

1: LNG lorry 10: LNG receiving path 11: First LNG pump 20: Heat exchanger 21: LNG saturated liquid path 30: Heating circuit 31: Liquefied gas path 32: Evaporator 33: Evaporative gas path 40: LNG saturated liquid storage Tank 41: Upper boil-off gas space 50: LNG saturated liquid supply path 51: Second LNG pump 52: Dispenser 60: Heating gas supply unit 70: LNG receiving tank 71: Cooling line

Claims (5)

LNG receiving route and
A heat exchanger that heats the LNG received in the above LNG receiving path by heat exchange with a heating gas to make it an LNG saturated liquid.
An LNG saturated liquid storage tank for storing the LNG saturated liquid obtained in the heat exchanger, and an LNG saturated liquid storage tank.
One or more LNG saturated liquid delivery paths for supplying the LNG saturated liquid stored in the LNG saturated liquid storage tank, and
A heating circuit for taking out the liquefied heating gas condensed and liquefied by the heat exchanger, heating it, and returning it to the heat exchanger as the heating gas again.
It is characterized by having a heating gas supply unit that communicates the upper boil-off gas space of the LNG saturated liquid storage tank with the heat exchanger and supplies the boil-off gas as the heating gas to the heat exchanger. LNG saturated liquid supply device. The LNG saturated liquid supply device according to claim 1, wherein a first LNG pump for boosting LNG received from the LNG transport means is provided in the LNG receiving path. The LNG saturated liquid supply device according to claim 1 or 2, wherein a second LNG pump for boosting the LNG saturated liquid is provided in the LNG saturated liquid delivery path. The LNG saturated liquid supply device according to any one of claims 1 to 3, wherein the heat exchanger is provided in the upper boil-off gas space of the LNG saturated liquid storage tank. The LNG saturated liquid according to any one of claims 2 to 4, wherein the LNG receiving path is provided with an LNG receiving tank that temporarily stores the LNG received from the LNG transport means before introducing it into the first LNG pump. Supply device.

Images