KR102107394B1 - Line system for refueling lng and recovering bog - Google Patents

Abstract

Disclosed is an LNG charging and BOG recovery line system. The present invention is to provide the LNG charging and BOG recovery line system which enables mutual storage between LNG storage tanks. The LNG charging and BOG recovery line system according to one embodiment of the present invention includes: a pump which pressurizes LNG from the LNG tank; a dispenser for charging from the pump to a fuel tank of an LNG automobile; and a BOG back pressure sensor and a BOG back pressure control valve installed at a BOG line of a fuel tank rotor. An LNG fuel automobile charging system of the present invention adjusts the BOG back pressure control valve according to a back pressure sensor measurement value and an LNG pressure value during LNG charging. The dispenser is divided into an inner charging area and an outer charging area by a protective wall.

Description

LNG filling and BOG recovery line system {LINE SYSTEM FOR REFUELING LNG AND RECOVERING BOG}

The present invention relates to an LNG filling and BOG recovery line system, and more specifically, LNG and BOG returned when refueling to an LNG fuel vehicle through a dispenser from an LNG storage tank can be reused without loss, and mutual storage between LNG storage tanks is possible. LNG filling and BOG recovery line systems.

LNG means liquefied natural gas. Natural gas is produced when oil is produced in an oil field (dielectric gas, oil well gas), and crude oil is produced from a gas well (gas non-gas, gas well gas). The main component of natural gas is paraffin-based hydrocarbons, and especially methane is the main component (80 to 90%, depending on the region). Brunei acid is composed of 90% methane, 6% ethane, 3% propane, and 1% other gases. In general, it is used as fuel for power generation and city gas, but it is necessary to reduce the volume in order to transport it abroad, and it is liquefied at 1 atm. It is transported to the tanker at a volume of atmospheric pressure of 0.0024 m3) In order to use LNG received at the import base as a liquid at -162 ° C as power generation or city gas, it is necessary to vaporize it again to form a gas. In this case, 120 kcal / kg of latent heat of evaporation, 80 kcal / kg of sensible heat, and 200 kcal / kg of total heat are discharged.

Liquefied natural gas storage tanks include ground tanks, soil-freezing underground tanks, and PS concrete underground tanks, and metal double-sided tanks are generally used as ground tanks.

This tank has a double inside and outside. The inner cabinet is in contact with liquefied natural gas and withstands the weight of the liquid. The outer shell creates a heat shield between the inner cabinet to maintain an inert gas or insulating material, or secondary. It serves as a firewall. The cabinet uses materials that can withstand a low temperature of -162 ℃, for example, aluminum or 9% nickel steel, and the outer shell usually uses carbon steel.

Insulating materials are also used at the bottom of the tank, and further measures are being taken to prevent frostbite (a phenomenon in which water in the soil freezes and expands to raise the tank). A soil freezing tank is a tank that digs a large cylindrical hole while freezing the ground, stores liquefied natural gas in it, and then covers the roof. In addition, underground tanks are constructed with PS concrete tank sidewalls.

Large tanks are used for transporting LNG, and attention is paid to shipbuilding technology to prevent leakage, complete insulation and low temperature, and to maintain the stability of shrinking tanks. The tank structure can be divided into an independent tank type and an assembled tank type. The former is a method in which the cargo tank itself is independent of the hull strength member, supporting the weight of the contents and storing the entire tank in the hull. . The latter is a method in which the tank wall (그대로) is integral with the hull strength member.

Making liquefied natural gas back into gas is much easier than liquefaction, and in principle is achieved by heat exchange, which is opposite to cooling. Any heat can be used for this heat source, and if this heat exchange is used effectively, other objects can be cooled, so that some of the cost of natural gas can be recovered in this process. If there is no suitable heat source, it can be heated using seawater or river water. Depending on the method of applying heat, it can be divided into the open-rack method and the medium heat medium method. The former is a method of re-gasification by sending a liquefied natural gas inside and seawater outside by making a tube and an endothermic fin made of aluminum alloy, etc., and the latter does not directly exchange heat with a heat source, but uses an intermediate heat medium. It is a method of indirect heat exchange.

Meanwhile, BOG is a kind of LNG loss, which is an important problem in the transportation of LNG. In addition, there is a risk that the storage tank is damaged when the pressure in the storage tank increases as the BOG accumulates in the storage tank. Accordingly, various methods for treating BOG have been studied, and recently, a method of burning BOG with a gas combustor, a method of re-liquefying and returning it to a storage tank, a method of using BOG as an energy source of a ship's engine, etc. are used. However, it is not a fundamental countermeasure to suppress the occurrence of BOG, but a secondary countermeasure to treat the generated BOG. In addition, the method of burning BOG or using it as an energy source of the engine is uneconomical by reducing the amount of LNG as a cargo, and in particular, has a problem of causing environmental pollution due to combustion of BOG. Therefore, reuse and utilization of BOG without loss is very important.

Republic of Korea Patent Application No. 1020060034976

In an embodiment of the present invention, when refueling an LNG fueled vehicle through a dispenser from an LNG storage tank to overcome the problems of the prior art, the returned LNG and BOG are reused without loss, and mutual storage between the LNG storage tanks is possible. To provide LNG filling and BOG recovery line systems.

According to an aspect of the present invention, an LNG vehicle fuel filling system comprising: a pump for pressurizing LNG from an LNG tank; A dispenser filling the fuel tank of the LNG vehicle from the pump; A BOG back pressure sensor and a BOG back pressure control valve installed on the BOG line of the fuel tank rotor; During the charging of LNG, the BOG back pressure control valve may be adjusted according to the measured value of the back pressure sensor and the LNG pressure value.

The dispenser is divided into an internal charging zone and an external charging zone by a protective wall. The BOG back pressure sensor and the BOG back pressure control valve may be located in the external charging zone.

An icing vent valve installed at a position where the BOG back pressure regulating valve passes through the external charging zone; The icing vent valve may remove the water mixed in the BOG discharge hose through external opening after blocking the supply of LNG. Due to this, when the BOG is returned to the LNG tank, the formation of icing particles in the LNG tank due to moisture inflow can be prevented in advance.

A part of LNG is returned from the front end of the dispenser, and a return line is formed to be re-introduced into the LNG tank. Heat transfer between LNG-BOG by heat transfer of return BOG or LNG-BOG mixed flow by cooling heat of the pipe cooled by passing through LNG is formed. An induced LNG-BOG integrated return pipe may be attached to the LNG tank.

The LNG-integrated return pipe may be a single center pipe through which LNG and BOG are respectively passed or mixed according to each return mode and a double pipe structure for insulating the same.

The center pipe and the double pipe may be insulated.

According to another aspect of the present invention, there is a second LNG vehicle fuel filling system that is the same as the LNG vehicle fuel filling system, so that the filling of the LNG fuel tank and the second LNG fuel tank may be possible.

Charging between the LNG fuel tank and the second LNG fuel tank may be performed through a return line after being pressurized.

The present invention is a pump for pressurizing LNG from the LNG tank, a dispenser for filling the fuel tank of the LNG vehicle from the pump, a BOG back pressure sensor and a BOG back pressure control valve installed in the BOG line of the fuel tank rotor, and a back pressure sensor measurement value during LNG charging. The BOG back pressure regulating valve is adjusted according to the LNG pressure value, and the dispenser is an invention related to an LNG fuel vehicle charging system that is divided into an internal charging zone and an external charging zone by a firewall.

The BOG back pressure sensor and the BOG back pressure control valve are located in the external charging zone, and the icing vent valve and the icing vent valve installed in the position passing through the BOG back pressure control valve are blocked in the supply of LNG and then opened in the BOG discharge hose through external opening. Another feature is to remove the mixed moisture.

In addition, some of the LNG is returned from the front end of the dispenser, and a return line is formed to re-enter the LNG tank. LNG-BOG that recondenses the BOG by heat transfer between the pipe and the returned BOG using the cooling heat of the pipe cooled by passing through the LNG. The integrated return piping is attached to the LNG tank, and the second LNG fueling system is the same as the LNG fueling system. Thereby, charging of the LNG fuel tank and the second LNG fuel tank is possible, and charging between the LNG fuel tank and the second LNG fuel tank is performed through a return line after being pressurized.

According to one embodiment of the present invention, the LNG filling and BOG recovery line system improves efficiency by reusing the returned LNG and BOG without loss when refueling from the LNG storage tank to the LNG fuel vehicle through a dispenser, and improving the efficiency of the LNG storage tank. It is possible to enable mutual storage of the liver.

1 is an LNG main line for charging LNG.
2 is a return line when charging LNG.
3 is a BOG recovery line.
4 is a transfer system between LNG storage tanks capable of transferring LNG between vehicle fuel tanks.

The embodiments described below are provided so that those skilled in the art can easily understand the technical spirit of the present invention, and the present invention is not limited thereto. In addition, matters expressed in the accompanying drawings may be different from those actually implemented as schematic drawings to easily describe embodiments of the present invention.

When a component is referred to as being connected to or connected to another component, it should be understood that other components may exist in the middle, although they may be directly connected or connected to the other component.

And "connection" herein includes direct and indirect connections between one member and another member, and may mean all physical connections such as adhesion, attachment, fastening, bonding, and bonding.

In addition, expressions such as 'first, second', etc. are expressions used only for distinguishing a plurality of components, and do not limit the order or other features between components.

Singular expressions include plural expressions unless the context clearly indicates otherwise. The terms "comprises" or "haves" are intended to mean the presence of features, numbers, steps, actions, components, parts or combinations thereof described in the specification, one or more other features or numbers, It can be interpreted that steps, actions, components, parts or combinations thereof can be added.

1 is an LNG main line for filling LNG (red thin line).

LNG pressurized through the pump 30 connected along the pipe 20 from the LNG storage tank 10 is injected into the fuel tank 80 to the LNG vehicle through the dispenser. The dispenser serves as a kind of lubricator between the LNG storage tank 10 and the LNG vehicle, and BOG discharged from the fuel tank 80 of the LNG vehicle during charging is also allowed to pass through the dispenser, and temperature pressure is measured. LNG pressurized through the pump 30 flows into the dispenser through the dispenser inlet pipe 40 to the fuel tank 80 through the filling pressure gauge 50, the filling hose 60, and the filling port 70 of the LNG vehicle. Is injected. On the other hand, not all of the pressurized LNG along the pipe from the LNG tank is filled in the vehicle fuel tank 80, and some may be returned.

2 is a return line when charging LNG (blue thick line).

When the LNG pressurized through the pump 30 connected along the pipe 20 from the LNG storage tank 10 is injected into the fuel tank 80 to the LNG vehicle through the dispenser, a return line is formed just before the dispenser flows in. . That is, some of the pumped LNG is recovered into the LNG tank along the return lines 210, 220 and 230. At this time, before returning to the LNG tank, BOG and the return line of LNG may be introduced through the LNG-BOG integrated return pipe 270. The need is explained again in the BOG.

3 is a collection line of BOG remaining in a vehicle fuel tank while charging LNG (red thick line).

The BOG outlet 90 located at the top of the fuel tank 80 of the LNG vehicle passes through the BOG discharge hose 100, and the vehicle fuel tank BOG back pressure control valve 120, the icing vent valve (Icing, 110), and the BOG return. It is recovered to the LNG storage tank 10 through the line 130 (140) 150 and the LNG-BOG integrated return pipe 270. The BOG back pressure sensor and the BOG pressure to measure the pressure of the fuel tank BOG of the LNG vehicle are adjusted. The back pressure regulating valve 120 adjusts the BOG gas back pressure of the fuel tank of the LNG vehicle so that LNG filling can be smoothly performed during charging, and is located in the dispenser.The back pressure by the BOG during charging is the delivery pressure of the pump 30 (12 ~ 16 bar) level, normal charging becomes difficult due to the back pressure of the BOG of the LNG vehicle fuel tank, so the vehicle LNG fuel tank BOG back pressure regulating valve 120 is adjusted during charging. Meanwhile, the dispenser is based on the protection wall 240. Installed inside and outside, respectively, the internal charging area and external charging The back pressure sensor and the back pressure control valve 120 of the LNG vehicle fuel tank BOG are installed in the external charging area of the protective wall 240 of the dispenser to apply the actual back pressure applied to the LNG vehicle fuel tank 80.

When the filling hose 60 and the LNG filling port connection, the BOG outlet 90 and the BOG discharge hose 100 are combined during the LNG filling preparation work, moisture in the infiltrating air and the BOG in the fuel tank 80 of the LNG vehicle When the contained moisture, etc., enters the pipe during filling, it is frozen into fine ice grains by LNG and attached to the valve seat, which causes the valve to malfunction and leak. The icing vent valve 110 is installed in the dispense to remove moisture that may be mixed in the connection portion of the filling hose and the BOG in the LNG vehicle fuel tank 80. In order to remove moisture, by connecting the BOG discharge hose 100 and the discharge port 90 in a state where the LNG supply is blocked, open the vehicle fuel tank BOG back pressure control valve 120 and open the icing vent valve 110 for several seconds. After discharging through the external vent line, the valve is closed in the order of the icing vent valve 110 and the vehicle fuel tank BOG back pressure regulating valve 120. Like the vehicle fuel tank BOG back pressure regulating valve 120, the icing vent valve 120 is also installed in the external charging area of the dispenser of the protective wall 240.

On the other hand, the BOG returned to the LNG storage tank 10 through the BOG return pipe causes the temperature and pressure of the LNG storage tank 10 to rise due to the temperature rise.

To prevent this, the integrated piping 180 mixes the LNG of the LNG line 170 and the BOG of the BOG line 160 to flow into the LNG storage tank 10. That is, it flows into the LNG storage tag through the integrated pipe outlet pipe 190 extending from the integrated pipe 180.

On the other hand, the LNG return line can be bypassed so that it flows in both directions of the upper and lower inlets of the LNG storage tank.

When returning LNG, the internal temperature of the integrated return pipe (270) is -165 ~ -140 ℃, and the pipe is insulated to return heat to the BOG and return to the integrated return pipe (270). By returning to the storage tank 10, the temperature and pressure of the LNG storage tank 10 is prevented, and the regeneration of BOG is reduced.

The LNG-BOG integrated return pipe 270 is located directly connected to the LNG storage tank 10 and may be treated with MLI (Multi Layer Insulation) vacuum insulation and insulation materials including urethane and cryogel.

4 is a transfer system between LNG storage tanks capable of transferring LNG between fuel vehicles of LNG vehicles. (Blue thin line)

Depending on the situation of the LNG storage tank 10, when return LNG cannot be recharged, or when the dispensing of one side does not operate normally, a very serious problem may occur. Therefore, it is possible to re-inject return LNG during charging into another storage tank, or to transfer LNG between the LNG storage tanks 10 as needed.

That is, when the LNG pressurized through the pump 30 connected along the pipe 20 from the LNG storage tank 10 is injected into the fuel tank 80 of the LNG vehicle through the dispenser, the returned LNG is the return line 210 ) 220, 230 may be recovered as the original LNG storage tank, but may be recovered as another interconnected LNG storage tank 10 '.

For convenience, another LNG storage tank interconnected may be referred to as a second LNG storage tank 10 ′, and the LNG storage tank previously referred to as a first LNG storage tank 10.

To this end, the multiple valve 500 is located on the return line 230 of the first LNG storage tank, and the multiple valve 500 'is located on the return line 230' of the second LNG storage tank, so that the multiple valve 500 It may be branched to the second LNG storage tank 10 'other than the original first LNG storage tank 10 via the return line 230' of the second LNG storage tank by adjustment of, 500 '. . Similarly, the return line 210 'of the second LNG storage tank and the return line 220 of the first storage tank (2) pressurized through the second LNG storage tank 10'-pipe 20'-pump 30' 230) is supplied to the first LNG storage tank (10). In this case, the return lines 210 and 230 of the first LNG storage tank, the return lines 210 'and 230' of the second LNG storage tank, and the multiple valves 500 and 500 'are constructed differently. However, the return line is commonly used for the first and second LNG storage tanks. The LNG fuel vehicle in the present invention is not necessarily limited to a vehicle, but can be applied to all means of transportation using LNG as a power source, such as a ship, and such charging control is controlled by the control unit of the LNG charging system, and each pipe is provided with a backflow prevention valve Can be installed.

Accordingly, the LNG filling and BOG recovery line system according to the present invention improves efficiency by reusing the returned LNG and BOG without loss when refueling from the LNG storage tank to the LNG fuel vehicle, and improves the efficiency and mutual storage between the LNG storage tanks. It can be made possible.

Those of ordinary skill in the art to which the present invention pertains will appreciate that the present invention may be implemented in other specific forms without changing its technical spirit or essential features. Therefore, the above-described embodiments are merely the most preferred embodiments selected to help the understanding of the skilled person among various possible embodiments, and the technical spirit of the present invention is limited or limited only by the presented embodiments Rather, it is revealed that various changes, additions, and changes are possible within a range that does not depart from the technical spirit of the present invention, and that other exemplary embodiments are possible. The scope of the present invention is indicated by the scope of the claims, which will be described later, rather than the detailed description, and all the changed or modified forms derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. Should be interpreted. In addition, the inventor has defined the terms or words used in the present specification and claims based on the principle that the concept of terms can be properly defined in order to explain his or her invention in the best way. It should not be interpreted as meaning only. In addition, the order of the components described in the above-described process does not necessarily have to be performed in a time-series order, and even if the order of performance of each component and step is changed, these processes may fall within the scope of the present invention. Yes, of course.

10: LNG storage tank 20: piping
30: pump 40: dispenser inlet pipe
50: filling pressure gauge 60: filling hose
70: filling port 80: fuel tank
90: BOG outlet 100: BOG discharge hose
110: Icing vent valve 120: BOG back pressure control valve
130, 140, 150: BOG return line 160: BOG line
170: LNG line 180: Integrated piping
210, 220, 230: Return line 240: Firewall
270: integrated return piping
10 ': 2nd LNG storage tank 20': piping
30 ': Pump 210', 230 ': Return line
500, 500 ': Multi-valve

Claims (8)

In the LNG vehicle fuel filling system,
A pump that pressurizes LNG from the LNG tank;
A dispenser filling the fuel tank of the LNG vehicle from the pump;
A BOG back pressure sensor and a BOG back pressure control valve installed on the BOG line from the fuel tank of the LNG vehicle;
Adjusting the BOG back pressure control valve according to the measured value of the back pressure sensor and the LNG pressure value during charging of LNG,
The dispenser is divided into an internal charging zone and an external charging zone by a protective wall.
The BOG back pressure sensor and the BOG back pressure control valve are located in the external charging zone,
An icing vent valve installed at a position where the BOG back pressure regulating valve passes through the external charging zone;
The icing vent valve is LNG vehicle fuel filling system characterized in that after removing the supply of LNG to remove moisture in the BOG through external opening. delete delete According to claim 1,
A part of LNG is returned from the front end of the dispenser, and a return line is formed to re-enter the LNG tank.
LNG-BOG LNG refueling system, characterized in that the heat transfer between the LNG-BOG integrated return piping is attached to the LNG tank. According to claim 4,
The LNG-BOG integrated return pipe is an LNG vehicle fuel filling system, characterized in that it has a single center pipe through which LNG and BOG pass or mix according to each return mode and a double pipe structure for insulating the same. The method of claim 5,
The appearance of the double pipe is LNG vehicle fuel filling system, characterized in that the insulation. In the LNG vehicle fuel filling system,
A pump that pressurizes LNG from the LNG tank;
A dispenser filling the fuel tank of the LNG vehicle from the pump;
A BOG back pressure sensor and a BOG back pressure control valve installed on the BOG line from the fuel tank of the LNG vehicle;
Adjusting the BOG back pressure control valve according to the measured value of the BOG back pressure sensor and the LNG pressure value during LNG charging,
The dispenser is divided into an internal charging zone and an external charging zone by a protective wall.
The BOG back pressure sensor and the BOG back pressure control valve are located in the external charging zone,
An icing vent valve installed at a position where the BOG back pressure regulating valve passes through the external charging zone;
The icing vent valve after the supply of LNG is cut off, moisture in the BOG is removed through external opening,
The fuel tank of the LNG vehicle can be charged to each other through a fuel line system and a return line of another LNG vehicle. delete

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