KR20210111566A - System and method for recycle of refrigerants in charging equipment of LNG - Google Patents

Abstract

The present invention relates to a refrigerant recycling system for a liquefied natural gas charging facility and a recycling method thereof. The refrigerant recycling system for a liquefied natural gas charging facility includes: an LNG storage tank part storing liquefied natural gas in an ultralow temperature state; a pump pumping the liquefied natural gas stored in the LNG storage tank part; an LNG dispenser supplying the liquefied natural gas in the ultralow temperature state pumped by the pump to a fuel tank of a vehicle in accordance with an amount required for charging; a cooler collecting boiloff gas produced when the fuel tank of the vehicle is being charged with the liquefied natural gas, to cool the same with the liquefied natural gas; and a liquefied nitrogen supply part supplying liquefied nitrogen to the cooler. The system also includes: an introduction valve for introducing nitrogen gas produced by a reaction between the liquefied nitrogen supplied to the cooler and the boiloff gas, into the inside of a gas storage tank; and a discharge valve discharging the nitrogen gas filling the inside of the LNG dispenser to the outside. The recycling method includes the following steps of: pumping liquefied natural gas in an ultralow temperature state stored in an LNG storage tank part through a pump; charging the liquefied natural gas in the ultralow temperature state in a fuel tank of a vehicle in accordance with a required amount; during the procedure of charging the fuel tank of the vehicle with the liquefied natural gas, converting boiloff gas evaporated by a temperature rise into liquefied natural gas through a heat exchange with liquefied nitrogen, and then, supplying the same to the LNG storage tank part; and supplying nitrogen gas produced by a heat exchange between the boiloff gas and the liquefied nitrogen to the LNG dispenser to charge the inside of the LNG dispenser with the nitrogen gas. Therefore, the present invention is capable of reducing costs for manufacturing facilities overall.

Description

Refrigerant recycling system and recycling method of liquefied natural gas charging facility {System and method for recycle of refrigerants in charging equipment of LNG}

The present invention relates to a refrigerant recycling system and recycling method of a liquefied natural gas charging facility for supplying and charging liquefied natural gas to a fuel tank of a vehicle, and more particularly, to LNG BOG re-liquefaction or LNG/ It relates to a refrigerant recycling system and recycling method of a liquefied natural gas charging facility for recycling after heat exchange _{of liquid nitrogen (LN 2} ), which is a refrigerant used for cooling BOG.

In general, liquefied natural gas (LNG) for supply to vehicles is a liquefied natural gas receiving facility, that is, after accommodating the liquefied natural gas in the LNG storage tank of the liquefied natural gas charging facility, and then supplying it to the vehicle for charging. supply and recharge.

At this time, the liquefied natural gas stored in the LNG storage tank is stored at a cryogenic temperature of -160°C to -150°C. It should be supplied to the charging vehicle by maintaining a constant and constant pressure.

1 is a configuration diagram schematically showing a conventional liquefied natural gas charging device, as shown, the conventional liquefied natural gas charging device includes an LNG storage tank unit 10 in which liquefied natural gas in a cryogenic state is stored; , a pump 20 for pumping the liquefied natural gas stored in the LNG storage tank, and a dispenser (charger) 30 for charging the liquefied natural gas in a cryogenic state pumped by the pump 20, The liquefied natural gas is supplied to the fuel tank of the vehicle 40 by the dispenser 30 to be filled.

However, as described above, when liquefied natural gas is supplied and charged to the fuel tank of a vehicle, boil-off gas (BOG) evaporated according to the temperature increase during the charging process is generated, and the boil-off gas thus evaporated is generated. As it leaks to the outside, not only economic loss occurs, but also a large amount of carbon is emitted when BOG is generated, which raises the problem of emitting greenhouse gases.

That is, during operation of the liquefied natural gas charging facility, the LNG storage tank unit 10, the pump 20, and the dispenser 30, as well as various valves, instruments, and pipes, etc. BOG is generated, and thus BOG is introduced into the LNG storage tank unit 10 to increase the pressure, so that the design pressure of the LNG storage tank unit 10 is exceeded.

Accordingly, as the boil-off gas is released to the outside through the safety valve of the LNG storage tank unit 10, the boil-off gas also leaks to the outside, causing safety problems and economic loss, as well as releasing a large amount of carbon when the boil-off gas is generated. There was a problem in that the greenhouse gas was emitted.

Accordingly, it was required to introduce a cooling system for lowering the temperature and pressure of boil-off gas (BOG) by installing a reliquefaction device or a cooler, and liquid nitrogen (LN ₂ ) may be considered as a suitable refrigerant here.

In this case, the liquid nitrogen refrigerant is _{vaporized into nitrogen gas (N 2} ) after heat exchange, and then discharged to the atmosphere or can be used after re-liquefaction. When designing a gas charging facility, designing and utilizing a system configuration and method that is recycled from the beginning can be efficiently secured by reducing facility investment cost and operating capital.

In particular, it is necessary to introduce a cooler or re-liquefier due to boil-off gas (BOG) generated during storage, pre-cooling, and charging. If a recycling system is configured so that it can be recycled for its intended purpose and used in connection with existing charging facilities and devices, it is possible to operate an efficient liquefied natural gas charging facility by reducing the operating cost of the liquefied natural gas charging facility and reducing the investment cost for related equipment. , a solution for this is required.

Korean Patent Registration No. 10-1056984 (2011.08.09.)

The present invention has been devised in view of the various requirements as described above, and the technical problem to be solved by the present invention is to recover the boil-off gas leaked to the outside during the process of charging liquefied natural gas in the fuel tank of a vehicle, and to recover Liquid nitrogen refrigerant is supplied to the cooler to cool the BOG, but the inert nitrogen gas vaporized as the BOG is cooled by the cooler is supplied to the dispenser including the control box by an input signal, so that the inside of the dispenser is higher than atmospheric pressure. To provide a refrigerant recycling system and recycling method of a liquefied natural gas charging facility that prevents the occurrence of fire and explosion caused by electric sparks by maintaining pressure and blocking the inflow of external air.

In other words, as the internal pressure is higher than atmospheric pressure by supplying nitrogen gas of 2 bara or more in the dispenser including the control box, it blocks the inflow of external air and fills the inside with nitrogen gas, which is an inert gas. It is to provide a refrigerant recycling system and recycling method of a liquefied natural gas charging facility that enables the installation of a non-explosion-proof electric device in the dispenser, thereby reducing the cost of the instrumentation equipment.

In addition, another technical problem to be solved by the present invention is to recover the inert nitrogen gas vaporized by cooling the boil-off gas in the cooler without discharging it to the outside, _{store it in a separate N 2} gas storage tank, and then recycle it. To provide a refrigerant recycling system and recycling method of a liquefied natural gas charging facility that can reduce facility costs and operating costs.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

A refrigerant recycling system of a liquefied natural gas charging facility according to an embodiment of the present invention for solving the above problems includes: an LNG storage tank in which liquefied natural gas in a cryogenic state is stored; a pump for pumping the liquefied natural gas stored in the LNG storage tank unit; an LNG dispenser for supplying an amount of liquefied natural gas in a cryogenic state pumped by the pump to the fuel tank of the vehicle in an amount necessary for charging; a cooler for recovering boil-off gas generated during charging of the liquefied natural gas in the fuel tank of the vehicle and cooling it with liquefied natural gas; and a liquid nitrogen supply unit for supplying liquid nitrogen to the cooler, wherein the liquid nitrogen supplied to the cooler reacts with boil-off gas to introduce nitrogen gas generated into the N2 gas storage tank and the LNG dispenser internal set pressure a supply valve for supplying the N2 gas of the N2 storage tank in the following case; It may be configured to further include a discharge valve for discharging the nitrogen gas filled in the LNG dispenser to the outside.

At this time, the LNG dispenser is provided with a first pressure sensor for detecting an internal pressure, and when the pressure value sensed by the first pressure sensor is equal to or less than a set value, the supply valve is opened to introduce nitrogen into the heat exchanger. It may further include a control unit for controlling the gas to be supplied and to discharge the nitrogen gas inside the heat exchanger to the outside by opening the discharge valve when the pressure value sensed by the first pressure sensor is greater than or equal to a set value have.

In addition, an N2 gas storage tank may be provided between the cooler and the LNG dispenser, and an N2 tank for a pneumatic actuator connected by a pressure valve may be installed at one side of the N2 gas storage tank.

In addition, a bypass flow path may be installed between the LNG dispenser and the discharge valve, and a defrosting nozzle unit may be installed on the bypass flow path with an on/off defrosting valve interposed therebetween.

On the other hand, the refrigerant recycling method of the liquefied natural gas charging facility according to an embodiment of the present invention comprises the steps of: (a) pumping the cryogenic liquefied natural gas stored in the LNG storage tank unit with a pump; (b) charging the fuel tank of the vehicle with the required amount of the liquefied natural gas in the cryogenic state; (c) during the charging process of the liquefied natural gas to the fuel tank of the vehicle, heat-exchanging the boil-off gas evaporated by the temperature rise with liquid nitrogen to convert it into liquefied natural gas, and then supplying it to the LNG storage tank unit; and (d) supplying nitrogen gas generated by heat exchange between the boil-off gas and liquid nitrogen to the LNG dispenser to fill the inside of the LNG dispenser with nitrogen gas.

Here, the nitrogen gas generated by the heat exchange is supplied to the N2 gas storage tank and recycled for maintenance or cleaning of various facilities, or for the purpose of removing the frost generated in the filling nozzle of liquefied natural gas. may include steps.

Other specific details of the invention are included in the detailed description and drawings.

According to the refrigerant recycling system and the recycling method of the liquefied natural gas charging facility according to an embodiment of the present invention, the BOG leaked to the outside during the process of charging the liquefied natural gas in the fuel tank of the vehicle is recovered and cooled, so that it is liquefied again. By supplying natural gas to the LNG storage tank after generating it, economic loss due to the leakage of boil-off gas is minimized, and the external emission of boil-off gas is reduced to suppress the emission of greenhouse gas, thereby eliminating the concern of environmental pollution. An effect may be provided.

In addition, according to the refrigerant recycling system and recycling method of a liquefied natural gas charging facility according to an embodiment of the present invention, liquid nitrogen is supplied to a cooler to cool the recovered BOG, but vaporizes as the BOG is cooled in the cooler By supplying the inert nitrogen gas to the dispenser according to the input signal, the internal pressure of the dispenser is filled with inert nitrogen gas of 2 Bara or more, and the inflow of external air is blocked, thereby preventing fire and explosion caused by electric sparks. A preventive effect may also be provided.

In addition, according to the refrigerant recycling system and recycling method of a liquefied natural gas charging facility according to an embodiment of the present invention, as nitrogen gas is supplied into the dispenser and the inside is charged, the risk of fire and explosion caused by electric sparks is eliminated, Relatively inexpensive non-explosion-proof electrical and instrumentation equipment can be installed, thereby reducing the cost of the overall manufacturing facility.

In addition, according to the refrigerant recycling system and recycling method of a liquefied natural gas charging facility according to an embodiment of the present invention, the inert nitrogen gas vaporized by cooling the boil-off gas in the cooler is recovered without discharging to the outside and separate N2 gas By recycling after storage in a storage tank, a useful effect of reducing equipment costs and operating costs can also be provided.

The effect according to the present invention is not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a configuration diagram schematically showing a conventional liquefied natural gas filling system
2 is a configuration diagram schematically showing a refrigerant recycling system of a liquefied natural gas charging facility according to an embodiment of the present invention.
Figure 3 is a block diagram for showing the operating relationship of the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention.
Figure 4 is a flow chart sequentially showing the operation relationship of the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention.
Figure 5 is a flow chart showing the inert nitrogen gas recycling relationship of the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention.

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Accordingly, in some embodiments, well-known process steps, well-known structures, and well-known techniques have not been specifically described in order to avoid obscuring the present invention.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, includes and/or comprising means not excluding the presence or addition of one or more other components, steps and/or actions other than the stated components, steps and/or actions. use it as And, “and/or” includes each and every combination of one or more of the recited items.

Further, the embodiments described herein will be described with reference to perspective, cross-sectional, side view and/or schematic views that are ideal illustrative views of the present invention. Accordingly, the form of the illustrative drawing may be modified due to manufacturing technology and/or tolerance. Accordingly, embodiments of the present invention are not limited to the specific form shown, but also include changes in the form generated according to the manufacturing process. In addition, in each drawing shown in the embodiment of the present invention, each component may be illustrated in a somewhat enlarged or reduced manner in consideration of convenience of description.

Hereinafter, a liquefied natural gas filling apparatus and a filling method according to an embodiment of the present invention will be described in detail based on the accompanying exemplary drawings.

2 is a configuration diagram schematically illustrating a refrigerant recycling system of a liquefied natural gas charging facility according to an embodiment of the present invention, and FIG. 3 is an operational relationship of a refrigerant recycling system of a liquefied natural gas charging facility according to an embodiment of the present invention. It is a block diagram to show.

First, as shown in Figure 2, the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention, the LNG storage tank unit 100, the pump 200, the N2 gas storage tank 300, the control It may be configured to include an LNG dispenser (fuel supply charger) 700 including a box, a cooler 600 , and a liquid nitrogen supply unit 500 .

In addition, the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention includes an inlet valve 610 installed between the cooler 600 and the N2 gas storage tank 300 and the N2 gas storage tank 300 . A supply valve 310 installed on one side of the , a discharge valve 730 installed on one side of the LNG dispenser 700 , and an inlet valve 610 and a supply valve 310 by the pressure in the LNG dispenser 700 . and a control unit 800 for controlling the opening and closing of the discharge valve 730 .

Here, a first pressure sensor 702 for measuring an internal pressure and applying a signal to the controller 800 may be provided inside the LNG dispenser 700 .

In addition, in the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention, the N2 storage tank 330 for a pneumatic actuator with the pressure valve 320 interposed therebetween in one direction of the N2 gas storage tank 300 is may be installed, and a second pressure sensor 302 for measuring the internal pressure and applying a signal to the control unit may be provided in the N2 storage tank 330 for the pneumatic actuator. to explain

In addition, the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention branches the bypass flow path to the flow path between the LNG dispenser 700 and the discharge valve 730, and removes frost on the bypass flow path The on/off valve 740 and the defrosting nozzle unit 750 may be disposed, and the operational relationship of these components will also be described in detail later.

The LNG storage tank unit 100 stores liquefied natural gas at -160°C to -150°C in an ultra-low temperature state, and the pump 200 pumps the liquefied natural gas stored in the LNG storage tank unit 100. can

In addition, the LNG dispenser 700 is pumped by the pump 200 to supply and charge the required amount of liquefied natural gas to the fuel tank of the vehicle 400 , and therein various electricity for controlling the flow rate of liquefied natural gas .A control box such as an instrumentation device is installed.

Therefore, when the fuel tank of the vehicle 400 is charged by supplying the liquefied natural gas, the liquefied natural gas in a cryogenic state by the operation of the pump 200 is supplied to the LNG dispenser 700 and to the LNG dispenser 700 . The supplied cryogenic liquefied natural gas is supplied to the fuel tank of the vehicle 400 to be charged.

At this time, a charging valve 710 and a charging nozzle 720 are provided between the LNG dispenser 700 and the fuel tank of the vehicle 400 , so that when the charging valve 710 is opened, the vehicle ( 400) is supplied to the fuel tank to be filled.

At this time, in the process of filling the fuel tank of the vehicle 400 with liquefied natural gas, some of the liquefied natural gas is generated as boil-off gas (BOG) due to the temperature rise. The recovery is made at ( 600 ), and at the same time, the liquid nitrogen refrigerant pressurized from the liquid nitrogen supply unit ( 500 ) is supplied to the cooler ( 600 ).

Accordingly, the boil-off gas recovered to the cooler 600 is again generated as liquefied natural gas by reaction with liquid nitrogen, and the liquefied natural gas thus generated is recovered to the LNG storage tank unit 100 again to be stored. As a result, the loss of liquefied natural gas is reduced, so that economic loss can be minimized.

On the other hand, liquid nitrogen supplied to the cooler 600 is converted into gaseous nitrogen gas by heat exchange with the boil-off gas supplied to the cooler 600 , and the converted nitrogen gas is input from the control unit 800 . After flowing into the N2 gas storage tank 300 through the inlet valve 610 according to the signal, the inflow into the LNG dispenser 700 through the supply valve 310 may be made.

As described above, the LNG dispenser 700 fills and controls the amount required for the fuel tank of the vehicle 400 with liquefied natural gas in a cryogenic state, and a control box including various electrical and instrumentation devices is installed therein. do.

Therefore, when external air flows into the LNG dispenser 700 , there is a risk of generating an electric spark, and in this case, a fire or explosion accident may occur.

Accordingly, in the prior art, expensive explosion-proof equipment was installed inside the LNG dispenser 700 in order to dispel the fear of fire and explosion accidents as described above. By introducing the generated nitrogen gas, the inflow of external air can be blocked.

That is, when the fuel tank of the vehicle 400 is filled with liquefied natural gas, nitrogen gas flows into the LNG dispenser 700 so that the inside is filled with nitrogen gas, so that the outside air is introduced into the inside. By blocking the device in advance, it is possible to dispel the fear of fire and explosion accidents caused by electric sparks.

Accordingly, a first pressure sensor 302 for measuring internal pressure is provided inside the LNG dispenser 700 , and the first pressure sensor 302 transmits the sensed pressure value to the control unit 800 , and the control unit 800 can control the opening and closing of the inlet valve 610, the supply valve 310, and the outlet valve 730 by the input signal. same as

4 is a flowchart sequentially illustrating the operation relationship of the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention.

In the process of filling the fuel tank of the vehicle 400 with liquefied natural gas, the first pressure sensor 302 installed inside the LNG dispenser 700 senses the pressure inside the LNG dispenser 700, and transmits the detected signal. It is transmitted to the control unit (800).

The control unit 800 applies an open signal to the inlet valve 610 and the supply valve 310 when the pressure inside the LNG dispenser 700 is equal to or less than a set value by the detection signal input from the first pressure sensor 302 . By doing so, nitrogen gas from the cooler 600 flows into the LNG dispenser 700 through the N2 gas storage tank 300 .

In this case, in order for nitrogen gas to flow into the LNG dispenser 700 from the cooler 600 , as described above, the liquid nitrogen refrigerant for cooling the BOG must be continuously introduced. ) is, of course, done.

On the other hand, when the pressure by the detection signal input from the first pressure sensor 302 is equal to or greater than the set value, the control unit 800 applies an open signal to the discharge valve 730 to lower the pressure inside the LNG dispenser 700 . can make it

Therefore, according to the refrigerant recycling system of the liquefied natural gas charging facility according to the embodiment of the present invention, the BOG leaked to the outside during the process of charging the natural liquefied gas in the fuel tank of the vehicle 400 is recovered and evaporated as it cools. Economic loss due to gas leakage is minimized, and since the external emission of boil-off gas is reduced, the emission of greenhouse gas is suppressed, and thus the effect of alleviating the concern of environmental pollution can be provided.

In addition, according to the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention, liquid nitrogen is supplied to the cooler 600 to cool the recovered BOG, but the cooler 600 cools the BOG By supplying the vaporized inert nitrogen gas to the LNG dispenser 700 according to the input signal, the inside of the LNG dispenser 700 is filled with nitrogen gas, and the inflow of external air into the LNG dispenser 700 is blocked. Accordingly, the effect of preventing the occurrence of fire and explosion caused by electric sparks can be provided.

In addition, according to the refrigerant recycling system of the liquefied natural gas charging facility according to the embodiment of the present invention, as nitrogen gas is supplied to the LNG dispenser 700 and the inside is charged, the risk of fire and explosion caused by electric sparks is eliminated. , it is possible to install a relatively inexpensive non-explosion-proof electric and instrumentation device in the LNG dispenser 700, so that the cost of the overall manufacturing facility can be reduced.

On the other hand, Figure 5 is a flow chart showing the inert nitrogen gas recycling relationship of the refrigerant recycling system of the liquefied natural gas charging facility according to an embodiment of the present invention, inert nitrogen gas vaporized as the boil-off gas is evaporated in the cooler 600 can be used for recycling without discharging to the outside as described above.

That is, when the pressure by the detection signal input from the first pressure sensor 302 is equal to or greater than the set value, the control unit 800 does not apply an open signal to the discharge valve 730, but the on/off valve 740 for defrosting. ) by applying an open signal to ( S140 ), the inert nitrogen gas may be supplied to the defrosting unit 750 .

As such, the inert nitrogen gas supplied to the defrosting unit 750 may be recycled for the purpose of removing the frost generated in the charging nozzle 720 .

On the other hand, when the pressure by the detection signal input from the first pressure sensor 302 is equal to or greater than the set value, the control unit 800 does not apply an open signal to the discharge valve 730 and the defrosting on/off valve 740 . Also, in a state in which the supply valve 310 also does not apply the open signal, the inert nitrogen gas may be supplied to the storage tank 330 for the pneumatic actuator by applying the open signal to the pressure valve 320 .

In this way, the inert nitrogen gas supplied to the storage tank 330 for the pneumatic actuator is reduced to a pressure of about 7 to 7,5 Bara by the pressure valve 320, and then the supply is made, and the inert nitrogen gas supplied in this way It can also be recycled for purposes such as maintenance and cleaning of various facilities of liquefied natural gas filling facilities.

That is, in most cases, a separate air compressor system and an air tank are installed in the conventional liquefied natural gas filling facility for the maintenance and cleaning of various facilities. 330), and recycling it for maintenance and cleaning of various facilities of the liquefied natural gas filling facility, thereby reducing equipment costs and reducing operating costs as there is no need to have a separate air compressor system and air tank configuration. A possible effect may be provided.

Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

100: LNG storage tank unit 200: pump
300: N2 gas storage tank 310: supply valve
320: pressure valve 330: N2 storage tank for pneumatic actuator
400: vehicle 500: liquid nitrogen supply unit
600: cooler 610: inlet valve
700: LNG dispenser 710: filling valve
720: filling nozzle 730: discharge valve
740: on/off valve for defrosting
750: defrosting nozzle unit
800: control unit

Claims (6)

LNG storage tank unit for storing liquefied natural gas in a cryogenic state;
a pump for pumping the liquefied natural gas stored in the LNG storage tank unit;
an LNG dispenser for supplying an amount of liquefied natural gas in a cryogenic state pumped by the pump to the fuel tank of the vehicle in an amount necessary for charging;
a cooler for recovering boil-off gas generated during charging of the liquefied natural gas in the fuel tank of the vehicle and cooling it with liquefied natural gas; and
Comprising a liquid nitrogen supply for supplying liquid nitrogen to the cooler,
an inlet valve for introducing nitrogen gas generated by reacting liquid nitrogen supplied to the cooler with boil-off gas into the N2 gas storage tank and a supply valve for supplying the N2 gas of the N2 gas storage tank when the internal pressure of the LNG dispenser is below a set pressure;
Refrigerant recycling system of a liquefied natural gas charging facility, characterized in that it further comprises a discharge valve for discharging the nitrogen gas filled in the LNG dispenser to the outside.
The method of claim 1,
In the LNG dispenser,
A first pressure sensor for sensing the internal pressure is provided,
When the pressure value sensed by the first pressure sensor is less than or equal to a set value, the supply valve is opened to supply nitrogen gas into the heat exchanger,
When the pressure value sensed by the first pressure sensor is greater than or equal to a set value, the liquefied natural gas further comprises a control unit for controlling to open the discharge valve to discharge the nitrogen gas inside the heat exchanger to the outside. Refrigerant recycling system for charging facilities.
The method of claim 1,
An N2 gas storage tank is provided between the cooler and the LNG dispenser, and a pneumatic actuator connected by a pressure valve is installed at one side of the N2 gas storage tank.
The method of claim 1,
Refrigerant recycling system of a liquefied natural gas charging facility, characterized in that a bypass flow path is installed between the LNG dispenser and the discharge valve, and a defrosting nozzle unit is installed on the bypass flow path with an on/off defrost valve interposed therebetween. .
The method of recycling a refrigerant using the refrigerant recycling system of the liquefied natural gas charging facility according to any one of claims 1 to 4,
(a) pumping the cryogenic liquefied natural gas stored in the LNG storage tank unit with a pump;
(b) charging the fuel tank of the vehicle with a required amount of liquefied natural gas in a cryogenic state by the heat exchanger;
(c) during the charging process of the liquefied natural gas to the fuel tank of the vehicle, heat-exchanging the boil-off gas evaporated by the temperature rise with liquid nitrogen to convert it into liquefied natural gas, and then supplying it to the LNG storage tank unit; and
(d) supplying nitrogen gas generated by heat exchange between the boil-off gas and liquid nitrogen to the LNG dispenser to fill the inside of the LNG dispenser with nitrogen gas; recycling method.
6. The method of claim 5,
The nitrogen gas produced by the heat exchange is,
Liquefied natural gas filling facility, characterized in that it comprises the step of recycling for the purpose of supplying the N2 gas storage tank for maintenance or cleaning of various facilities, or for removing the frost generated in the filling nozzle of the liquefied natural gas. Refrigerant recycling method.

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