EP3371506B1 - Device for fuelling motor vehicles with liquefied gas - Google Patents

Description

The invention relates to a device for refueling motor vehicles with a fluid made of liquefied gas, in particular liquefied natural gas, which is used as fuel, comprising at least one storage container, a cooling device, at least one conveying device through which the fluid can be fed from the storage container to at least one refueling device, by means of the Motor vehicles can be refueled with the fluid, and at least one line serving to supply the fluid to the refueling device.

Such fuels, also known as cryofuels, whose boiling point or critical temperature at the pressure prevailing in the storage container is far below normal ambient temperatures, are becoming increasingly important due to the increased energy demand and the increasing environmental pollution from conventional energy sources. They tend to evaporate easily as a result of pressure and temperature changes.

It is known to operate internal combustion engines of motor vehicles with natural gas. Since natural gas has a very low storage density and a lower volumetric calorific value than diesel at normal atmospheric pressure compared to, for example, diesel fuel, the natural gas is compressed to around 200 bar (CNG = Compressed Natural Gas) or liquefied by lowering the temperature to -162 ° C (LNG = Liquefied Natural Gas) so that a sufficient amount of energy can be carried in the vehicle.

In the case of LNG, part of the natural gas is constantly evaporating due to the heat supplied from the environment. The gaseous part of the natural gas mainly contains the more volatile constituents of the gas, which have a higher vapor pressure or a lower boiling temperature. The removal of part of the natural gas present in gaseous form in the storage container leads in the long term to an accumulation of higher hydrocarbons, in particular propane, in the cryogenic liquefied part of the natural gas. The high proportion of propane gas can be harmful to internal combustion engines. In addition, the mixture composition changes over time, which is undesirable.

In addition to land vehicles, such as, for example, buses, trucks and passenger cars, motor vehicles also include watercraft and aircraft.

The EP 2 229 551 A1 relates to a coupling for supplying a cryogenic fluid, in particular LNG, to a motor vehicle tank. For this purpose, the coupling is connected to a control line which is pressurized with a control fluid, for example compressed air at 10 bar. The release of the control pressure on the control line leads to the release of the fluid flow in the main line for supplying the fluid, so that it is ensured that the operator of the coupling does not come into contact with the cryogenic medium.

According to the EP 0 779 470 A1 a pressure delivery tank is connected via a supply line and a storage container via a return line with a coupling in order to refuel the motor vehicle with cryofuel flowing from the pressure delivery tank via the coupling. The outlet of the supply line and the inlet of the return line are arranged in the liquid cryofuel of the pressure delivery tank and the storage container, so that the liquid cryofuel of the pressure delivery tank can be conducted via this connection to the coupling or to the motor vehicle tank and back into the liquid cryofuel of the storage container . This enables the hose and the warm motor vehicle tank to be run cold, the heated liquid or gaseous cryofuel being fed to the liquid phase of the storage container.

The DE 195 01 332 A1 relates to a method for cooling a coaxial pipe system consisting of at least two coaxial pipes of a superconducting cable arranged at a distance from one another, which is arranged in a thermally well insulating sheath, a liquid gas being passed through the inner pipe. In order to keep both the inner tube and the tube surrounding the inner tube at one temperature, the annular gap sealed off at the end between the inner tube and the tube surrounding it is filled with a gas or gas mixture whose condensation temperature corresponds to the boiling point of the liquid gas flowing in the inner tube, preferably is higher, so that the gas or a gas of the gas mixture condenses on the inner tube and the dripping condensate cools the outer tube.

From the DE 10 2004 038 460 A1 a device for filling a container with liquid gas from a storage container is known, in which liquefied gas is removed from the storage container and fed to the container by means of a conveying device via a liquid supply line. Furthermore, gaseous gas is withdrawn from the container to be filled, at least partially liquefied by cooling in a heat exchanger and the liquefied gas is fed to the container to be filled.

In addition, from the U.S. 5,315,831 A as well as the U.S. 5,537,824 A Gas stations known, through which natural gas powered vehicles can be refueled with LNG and / or CNG.

The refueling of motor vehicles with gaseous fuels is also from the DE 721 995 A as well as the DE 10 2008 060 127 A1 known.

Also US5353849A discloses a device for refueling vehicles.

Furthermore, the DE 16 50 060 A on a flexible pipe made of concentric corrugated pipes for the transport of liquids or gases, for example for the flow and return of district heating pipes.

Starting from this prior art, the invention is based on the object of significantly improving the device for refueling motor vehicles. In particular, occurring thermal losses should be minimized.

This object is achieved according to the invention with a device according to the features of claim 1. The further embodiment of the invention can be found in the dependent claims.

According to the invention, a device is provided in which the line has a media-carrying central pipeline as a medium pipe and at least one further media-carrying pipeline which is arranged concentrically or coaxially with the central pipeline and delimits an annular space with the enclosed pipeline, the central pipeline and the at least one Annular space is used to supply or return the fluid from the liquefied gas or a gas stream and the outer pipeline is surrounded by a, for example, concentric casing pipe as an outer pipe, the casing pipe being thermally insulated from the outer pipe, the central pipe being designed as a corrugated metal pipe and wherein the central pipeline and at least one media-carrying annular space are not thermally insulated from one another. The central pipeline and the at least one annular space serve to supply and return the Fuel. The outer pipeline is surrounded by a likewise concentric jacket tube which encloses a thermal insulating material. The pipelines and the jacket pipe are each designed as thermally self-compensating metallic corrugated pipes, the central pipeline and the media-carrying annular space not being thermally insulated from one another. According to the invention, the concentric construction of the lines implemented in this way means that heat is extracted from the recirculated gas from the supplied fuel in order to cool or liquefy the gas. The coaxial partition between the pipelines forms an optimal exchanger surface due to the design as a corrugated pipe and the resulting increased surface area.

It is also particularly advantageous if the pipelines and the jacket pipe are each designed as thermally self-compensating metallic corrugated pipes in order to create a particularly flexible pipe that can also be laid in comparatively small radii.

In addition, it proves to be particularly practical if all the pipelines and the jacket pipe are arranged coaxially to one another.

In a further, also particularly promising modification of the invention, another pipeline dividing the annular space into an inner annular space and an outer annular space is arranged in the annular space between the central pipeline as a medium pipe and the pipeline. This makes it possible to set up a "standby mode" in which fuel is continuously withdrawn from the storage container and conveyed through the central pipeline to a flow reversal area in a line section of the line facing away from the storage container. The fuel is then fed back into the storage container through the inner annulus. This results in a continuous flow in the line, by means of which undesired heating can be avoided. In addition, a desired fuel supply is always available for refueling, so that the refueling process can be started immediately as soon as the line is connected to the motor vehicle.

It is particularly advantageous if the outer annular space is designed to divert the gas volumes displaced from the motor vehicle tank during refueling. The displaced gaseous volumes, also referred to as "boil-off gases", can thus be reliably conducted through the outer annular space into the storage container without an exchange with the fuel supplied to the motor vehicle, in order to liquefy it there again. Leakage of the gaseous components from the vehicle tank into the Environment can thereby be avoided and undesirable environmental pollution can be prevented.

For this purpose, according to a particularly useful configuration of the line, the outer annular space is equipped with a separate inlet opening and a separate outlet opening, so that the return of the boil-off gas can be implemented separately from the fuel, but through the same line.

Furthermore, it is particularly promising if the device has a storage container for LNG and the line connects the storage container to a refueling device. In this way, comparatively large distances between the refueling device and a central, for example underground, storage container can be easily overcome by means of the line. The storage container can also be connected in this way to a plurality of refueling devices at different locations if necessary.

In another, likewise particularly useful embodiment of the invention, a leakage monitoring device is arranged in the outer annular space between the casing tube and the outer pipeline. In this way, leaks that occur as a result of damage or wear can be detected quickly and reliably and the supply of fuel can be prevented. Methods for fiber-optic temperature measurement, for example, are suitable for this, with glass fibers, for example, being used as sensors for detecting leaks that occur. Alternatively, a pressure difference that occurs in the outer annular space can also be used as an indicator of a leak.

The annular space between the jacket pipe and the outer pipeline could be thermally insulated by a vacuum. It is also particularly practical if a thermal insulating material is provided in the annular space between the jacket pipe and the outer pipeline, which has a foam, in particular a polyurethane foam (PUR) as an essential component. The insulating material gives the line a high level of mechanical stability and resilience, so that the risk of damage is significantly reduced. In addition, the multiple walls prevent liquid or gaseous components from escaping into the environment. The line is preferably designed as a corrugated pipe so that it is self-compensating with regard to its thermal expansion.

Furthermore, it is also advantageous if the line is provided at least in sections with a peripheral reinforcement made of a braid. Such a reinforcement includes, for example, a woven mesh and / or a non-woven mesh, wherein the material of the reinforcement can be selected as desired. In this way the mechanical properties are further improved.

Fig. 1

eine Prinzipdarstellung einer erfindungsgemäßen Einrichtung mit einer Leitung für Treibstoff;

Fig. 2

eine perspektivische, teilweise geschnittene Darstellung eines Leitungsabschnittes der in Figur 1 gezeigten Leitung;

Fig. 3

einen Stand-By-Betrieb der Einrichtung;

Fig. 4

einen Entnahme-Betrieb der Einrichtung:

Fig. 5

einen Stand-By-Betrieb einer Variante der Einrichtung;

Fig. 6

einen Entnahme -Betrieb der in Figur 5 gezeigten Einrichtung.

The invention allows various embodiments. To further clarify its basic principle, one of them is shown in the drawing and is described below. This shows in

Fig. 1

a schematic diagram of a device according to the invention with a line for fuel;

Fig. 2

a perspective, partially sectioned illustration of a line section of FIG Figure 1 shown line;

Fig. 3

a stand-by mode of the device;

Fig. 4

an extraction operation of the facility:

Fig. 5

a stand-by mode of a variant of the device;

Fig. 6

an extraction operation of the in Figure 5 facility shown.

A device 1 according to the invention intended for refueling various vehicles and watercraft will be described below with reference to FIG Figures 1 to 4 explained in more detail. The device 1 enables various motor vehicles 2 to be refueled with a liquefied gas serving as fuel, in particular liquefied natural gas (LNG). For this purpose, the device has a storage container 3 designed as an above-ground tank for storing the liquefied gas, to which a cooling device (not shown) is assigned to liquefy the gas by cooling it to a suitable temperature range below -160 ° C. A line 5 designed as a corrugated pipe is arranged between a respective refueling device 4 designed as a tapping point, which is appropriately equipped in a manner known per se for the various types of motor vehicle.

The structural design of the line 5 is based on Figure 2 explained in more detail. The line 5 has a media-carrying central pipe 6 as a medium pipe, through which the fuel can be conveyed from the storage container 3 to the respective refueling device 4. This is enclosed concentrically by two further media-carrying pipes 7, 8, so that two media-carrying annular spaces 9, 10 are created, the function of which is described below with reference to the Figures 3 and 4th is explained. Finally, an outer jacket tube 11 is also provided as an outer tube, which encloses an annular insulating material 12 between the pipeline 8 and the jacket tube 11 in order to thermally insulate the line 5. In addition, the pipes 6, 7, 8 and the jacket pipe 11 are designed as thermally self-compensating metallic corrugated pipes. The central pipeline 6 and the media-carrying annular spaces 9, 10 are not thermally insulated from one another. Since the central pipeline 6 and the two media-carrying annular spaces 9, 10 are only separated by the wall surface of the respective pipelines 6, 7, but not thermally insulated, the medium carried in the annular spaces 9, 10 is replaced by the fuel carried in the central pipeline 6 Removed heat and cooled it accordingly. The coaxial partition between the pipes 6, 7, 8 forms an optimal exchanger surface due to the design as a corrugated pipe. The concentric design also improves the thermal insulation from the environment, as only a single external insulation is required. For checking purposes, a leakage monitoring device 13 is assigned to the outer annular space 10 between the jacket tube 11 and the pipeline 8 and thus enables the line to be continuously monitored for possible leaks.

In addition to the central pipeline 6 serving to transport the fuel, the two separate annular spaces 9, 10 between the concentric lines 7, 8 enable two different operating states, which are described below with reference to FIG Figures 3 and 4th are explained in more detail. For one, shows Figure 3 a "standby mode" in which fuel is continuously taken from the storage container 3 and conveyed through the central pipeline 6 to a flow reversal area 14 in front of a closed line end (not shown) in a line section facing away from the storage container 3. The fuel is then conveyed back into the storage container 3 in the direction of the arrow 16 through the inner annular space 9 and two line connections 15. This results in a continuous flow in the line 5, by means of which undesired heating can be avoided.

On the other hand, when the motor vehicle 2 is being refueled, the outer annular space 10 is used to divert the gas displaced from a motor vehicle tank, also called "boil-off gases". designated gaseous volumes are used. These are fed from the motor vehicle tank through a separate inlet opening 18, the outer annular space 10 and an outlet opening 19 without a connection to the central pipeline 6 in the direction of arrow 17 into the storage container 3 in order to liquefy it there again. This can prevent the gaseous constituents from escaping from the motor vehicle tank into the environment and prevent undesirable environmental pollution and hazards. In this operating mode, the fuel is supplied through the central pipe 6 as well as through the line connections 15 and the first, inner annular space 9. In this way, the volume flow is increased and the refueling process is correspondingly shortened.

In addition, the Figures 5 and 6th another variant of the device 1 is shown. The pipeline 6 is concentrically enclosed by only one media-carrying pipeline 7, through which a media-carrying annular space 9 is created. An outer jacket tube 11 forms the outer tube, which encloses an annular insulating material 12 between the annular space 9 and the jacket tube 11 in order to thermally insulate the pipes 6, 7. The central pipeline 6 and the media-carrying annular space 9 are not thermally insulated from one another, so that they are only separated by the wall surface of the pipeline 6, but not thermally insulated.

As indicated by the directional arrows, both the in Figure 5 operating mode shown for the supply of liquefied natural gas as well as in the in Figure 6 Operating mode shown for the suction of boil-off gases BOG each set a circulation of the liquefied natural gas present in the storage container through the pipeline 7. In this way, heat is withdrawn from the liquefied natural gas or boil-off gas routed alternatively in the pipeline 6 through the pipeline 7 and cooled accordingly, the boil-off gases being able to be liquefied by the heat withdrawal. <b> REFERENCE CHARACTERISTICS LIST </b> 1 Facility 16 Arrow direction 2 Motor vehicle 17th Arrow direction 3 Storage tank 18th Inlet opening 4th Refueling facility 19th Outlet opening 5 management 6th central pipeline 7th Pipeline 8th Pipeline 9 Annulus 10 Annulus 11 Jacket pipe 12 insulating material 13th Leak monitoring device 14th Flow reversal area 15th Line connection

Claims (10)

1. Facility (1) for refuelling motor vehicles (2) with a fluid which serves as fuel and which is composed of liquefied gas, in particular liquefied natural gas, comprising at least one storage container (3), a cooling device, at least one conveying device by means of which the fluid can be fed from the storage container (3) to at least one refuelling facility (4) for motor vehicles (2), and at least one line (5) which serves for the feed of the fluid to the refuelling facility (4), wherein the line (5) has a media-conducting central pipeline (6) as medium pipe and has at least one further media-conducting outer pipeline (8) which is arranged concentrically with respect to the central pipeline (6) and which, together with the enclosed pipeline (6), delimits an annular space (10), wherein the central pipeline (6) and at least one annular chamber (9, 10) serve for the feed and return of the fluid or of a gas flow, and in that the outer pipeline (8) is surrounded by a jacket pipe (11), wherein the jacket pipe (11) is thermally insulated with respect to the outer pipeline (7) and the central pipeline (6) is formed as a metallic corrugated pipe such that the central pipeline (6) and at least one media-conducting annular space (9, 10) are not thermally insulated with respect to one another, characterized in that, between the central pipeline (6) and the outer pipeline (8), there is arranged a further pipeline (7) which divides the annular space into an inner annular space (9) and an outer annular space (10).
2. Facility (1) according to Claim 1, characterized in that the pipelines (6, 7, 8) and the jacket pipe (11) are each formed as thermally self-compensating metallic corrugated pipes.
3. Facility (1) according to Claims 1 or 2, characterized in that all pipelines (6, 7, 8) and the jacket pipe (11) are arranged coaxially with respect to one another.
4. Facility (1) according to at least one of the preceding claims, characterized in that the outer annular space (10) is designed for discharging the gas volumes displaced out of the motor vehicle tank during the refuelling process.
5. Facility (1) according to at least one of the preceding claims, characterized in that the outer annular space (10) is equipped with a separate inlet opening (18) and a separate outlet opening (19).
6. Facility (1) according to at least one of the preceding claims, characterized in that the facility (1) has a storage container (3) for liquefied natural gas (LNG), and in that the line (5) connects the storage container (3) to a refuelling facility (4).
7. Facility (1) according to at least one of the preceding claims, characterized in that a leakage monitoring device (13) is arranged in the outer annular space (10) between the jacket pipe (11) and the outer pipeline (8).
8. Facility (1) according to at least one of the preceding claims, characterized in that a thermal insulation material (12) is arranged at least in certain portions in the annular space (10) between the jacket pipe (11) and the outer pipeline (8).
9. Facility (1) according to at least one of the preceding claims, characterized in that the line (5) is of self-compensating design.
10. Facility (1) according to at least one of the preceding claims, characterized in that the line (5) is equipped at least in certain portions with a peripheral reinforcement composed of an armouring.

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