WO2008000103A1

WO2008000103A1 - Road-transportable installation for liquefying and temporarily storing natural gas and refueling vehicles therewith

Info

Publication number: WO2008000103A1
Application number: PCT/CH2007/000301
Authority: WO
Inventors: Jean-Elie Tornare
Original assignee: Jean-Elie Tornare
Priority date: 2006-06-30
Filing date: 2007-06-19
Publication date: 2008-01-03

Abstract

The installation consists of a frame or a container and contains a supply line (9) for connecting the installation to the high-pressure line (8) of the compressor (3) of a CNG filling station. The installation also contains liquefying equipment for compressed natural gas (CNG), a cryogenic phase separator and storage tank (13), as well as a cryogenic pump (15) with a motor drive and a discharging line (14) with a pump counter for connecting to the liquefied gas tank of a vehicle or tanker. The liquefying device consists of a heat exchanger (10), downstream of which there is a Joule Thomson valve (12), from which the liquefied natural gas is passed into a cryogenic phase separator and storage tank (13). From said storage tank, a discharging line (14) with a cryopump (15) leads to a flexible discharging hose with a seal for connection to a liquefied gas tank of a vehicle. Moreover, a return line (16) for the gas phase from the phase separator tank and storage tank (13) leads through the heat exchanger (10), for taking up heat from the return line (9) and subsequently back into the pipeline (2). If necessary, the gas phase is compressed for this purpose by means of a separate low-pressure compressor.

Description

Road transportable plant for liquefying and

Caching of natural gas and

Fueling vehicles with it

This invention relates to a mobile, that means road transport-capable system, which can be connected to a CNG filling station (CNG = compressed natural gas) near a natural gas line. The plant receives natural gas from this line or pipeline, which is first liquefied and cached and then available for refueling in liquid or gaseous form. Caching in separate, larger tanks can also serve to bunk natural gas for periods of scarcity, whether due to political machinations, terrorist acts or force majeure.

By using natural gas as a fuel for vehicles, an impressive saving can be achieved. However, because natural gas with about 1000 ⁰ C has a higher ignition temperature than diesel with about 500 ⁰ C, it does not ignite in a conventional direct injection diesel engine by itself. It is therefore in terms of energy equivalent and depending on the setting and load of the First injected per injection about 5-10% as diesel, and immediately thereafter, the remaining 90-95% are injected as natural gas. This measure puts the ignition of the mixture in the frame a high-pressure direct injection (HPDI = High Pressure Direct Injection) safe. This two-phase and two-component injection takes place via a dual concentric injection nozzle. Its ignition acts as a liquid "spark plug." Its ignition causes the ignition of the compressed natural gas, so natural gas can replace 90 to 95% of the diesel, depending on its setting and load, always calculated in terms of its energy equivalent natural gas provides better knock properties. such mass-powered diesel vehicles have a 25-35% strength better fuel efficiency and also a better performance characteristics than with pure natural gas powered vehicles. compared to diesel vehicles encounter with natural gas powered vehicles about 50% less _NOx about 85% less soot particles and about 25% less CO ₂ .

There are gigantic natural gas deposits below the surface of the earth, especially in Russia, West and North Africa, the Middle East and South America. These deposits account for about half of all known hydrocarbon reserves in the world. Natural gas continues to impress as a particularly clean source of energy. When burned, it produces mainly CO ₂ and water vapor, the same substances that essentially make up the exhaled air of mammals. However, far less CO _{2 is produced} than with other combustible energy sources such as mineral oils or coal. Because natural gas is usually found where it is needed only a little, it has to be transported over long distances to the consumers. For this purpose, gas pipelines are used, and ships transport the natural gas in liquid form (LNG = liquid natural gas) over very long distances. When liquefying by cooling to a temperature of 111K, the volume is reduced by 600 times and at the place of destination, the natural gas must be gasified by supplying heat and then be finely distributed via piping systems.

The use of natural gas for operating vehicles would therefore be very meaningful in every respect. The implementation is hampered, however, mainly because there are very few gas stations available, compared to gasoline or diesel fueling even marginally few. This circumstance leads to the fact that so far largely only locally driven trucks and buses are operated with natural gas. They have a manageable radius of action and can always return to the same gas station, which means they do not need to take long stops and refuel stops far from their home base. However, the technology for operating natural gas vehicles is basically available and is already in use there and there, but it lacks an area-wide filling station network.

It is the object of the present invention to substantially compress the gas station network for natural gas and this purpose to create a mobile, that is road transportable system for liquid or gaseous refueling of vehicles with natural gas. The plant should also be used for liquefaction to bunker natural gas in separate LPG tanks to ensure filling of demand or demand peaks. This plant should be able to operate anywhere where gaseous or liquid natural gas is available, ie along existing natural gas pipelines or natural gas pipelines allow the practical, safe and rapid refueling of natural gas operated vehicles. The system should be designed so that it can be put into operation quickly and inexpensively wherever there is a CNG filling station. And the plant should be suitable as a indivisible whole road transport, so on site for setting up no major assembly work is needed, but the system as a whole just needs to be placed and connected.

The object is achieved by a road transportable system for liquefying and caching of natural gas from a CNG filling station to a pipeline, and for refueling vehicles with the recovered liquid natural gas, consisting of a frame or container containing a supply line for connecting the Plant to the delivery line of the compressor of a CNG filling station, further comprising a compressed natural gas liquefaction device (CNG), a cryogenic phase separator and storage tank, and a cryogenic pump with motor drive and bleed line with feed counter for connecting the same to the liquefied gas tank of a vehicle or tanker by the delivery line downstream of the cryopump is a flexible conduit with closure for tight connection to a liquid tank.

The invention is based on the fact that at many gas stations for compressed natural gas (CNG = Compressed Natural Gas), the compressors are needed only temporarily, and are parked especially at night. With the system proposed here, this can be exploited by the compressor and thus the compressed natural gas generated by him from this station for the provision of LNG is used, which can then be used for the refueling of individual vehicles, or for refueling tankers , which bring the liquid natural gas to decentralized filling stations where it can be liquid (LNG) or gaseous (LCNG = Liquid Compressed Natural Gas) fueled. The plant can also be used for the simple provision of liquid natural gas for bunkering in separate liquid tanks.

A typical such system is housed as indivisible whole in a steel frame or container and thus road transport suitable. Usual mass of a frame or container are for example B 243cm x H 260cm x L 915cm. Depending on the street registration regulations, larger frames or containers may be used, 20ft, 30ft, 40ft containers or even larger ones. The components of such a system are shown schematically in the drawings and with reference to these drawings, the system will be described in detail below and its function will be explained.

It shows:

Figure 1: A system with a combined Phasenseparatortank and storage tank, with liquefaction by using a Joule-Thompson valve;

Figure 2: A system with a phase separator tank and separate Storage tank, with liquefaction through the use of three heat exchangers, of which the middle includes a refrigeration unit at the same time, and a downstream injector;

Figure 3: A system with a phase separator tank and separate storage tank, with liquefaction by a heat exchanger and a downstream injector;

Figure 4: A system with a phase separator tank and separate storage tank, with liquefaction by using an injector and a downstream Joule-Thompson valve;

Figure 5: A system with a phase separator tank and separate storage tank, with liquefaction by using a vortex tube and a downstream injector.

The invention is based on the fact that the compressors of CNG filling stations are not permanently in operation. Especially at night they are turned off. During the day, they are used to fill gas cylinders with natural gas at 200 to 300 bar. When this task is done and the gas cylinder racks are full, in many cases the compressor is shut down prematurely and then not operated at night anyway. This circumstance benefits from the plant presented here. In a smallest version, it is designed for compressors that deliver about 100 m ³ natural gas to normal pressure per hour, that is, 100 Nm ³ / h. From this, about 30 liters of liquid natural gas per hour can be obtained, which accounts for about 18% of the natural gas consumed. The remainder returns to the pipeline in gaseous form. The 30 liters corresponding but an energy equivalent of 18O00 liters of natural gas to normal atmosphere or 18 Nm ³ . Larger systems are then designed for compressor capacities of up to 1200 Nm ³ / h and more, and accordingly, 360 liters of natural gas and more can be obtained per hour. The cryotank associated with the system is then filled correspondingly more rapidly or larger or more tanks can be filled and the natural gas is available for refueling or for temporary storage for one Bunkering ready.

In Figure 1, a simplest embodiment of the system is shown schematically with their components. Everything that is shown above the dividing line 1 does not belong to the plant, but to an already existing CNG filling station. Such filling stations are along natural gas pipelines, as such is shown schematically here and is designated 2. The CNG filling station has a compressor 3 to compress natural gas coming from Pipeline 2 via bleed line 4 to a higher pressure of 200 to 300 bar and to fill pressurized bottles 5 provided with this compressed natural gas (CNG). From the pressure bottles 5 a tapping point 6 (CNG dispenser) is fed, on which a valve own vehicle pressure tank can be filled with natural gas. These components all already exist, and the present invention is based on this situation. It provides a road transportable unit which provides liquid natural gas in place of an existing CNG filling station using the existing compressor and fills it into a storage tank from which vehicles can then be refueled with liquid natural gas tanks, or via a line a separate storage tank for bunkering can be filled. The system has a line connection 7, which branches off from the compressor high-pressure line 8 of the compressor 3 and leads via a feed line 9 to a heat exchanger 10. In this supply line, a molecular sieve 11 is optionally installed for the elimination of CO ₂ and water, if not already such a separator is present at the filling station. After that, the natural gas is passed via the line 9 through the high-pressure heat exchanger 10, in which it is cooled as soon as liquid natural gas is already available. Then, namely, the remaining gas phase flows from the liquid tank in the counterflow direction through the heat exchanger, as will be explained.

The natural gas in the supply line 9 has at a pressure of 200 to 300 bar, a temperature of up to 35 ° C. After being passed through the heat exchanger 10, it is pressed through a Joule-Thompson valve 12 and expanded, whereby the pressure is reduced to about 15 bar and the temperature of the gas simultaneously to 135K (-138 ⁰ C) decreases, whereby a proportion in the liquid state changes state and flows into a cryogenic tank 13 as a phase separator and storage tank. This cryotank 13 is in reality, and unlike the scheme shown, made of a horizontal cylindrical vessel with hemispherical ends and has superinsulation. For example, the cryotank 13 has a capacity of 3050 liters, of which 2875 liters are actually usable. The flowing through the Joule-Thompson valve 12 natural gas is liquefied there to about 18%. The remaining gas phase passes into the phase separator and storage tank 18. This gaseous natural gas is passed through the return line 16 in the opposite direction to the supply line 9 through the heat exchanger 10 and takes there from the supply line 9 heat, but only when the cryotank 13 contains liquid natural gas. In addition, the tank 13 can not be pumped out or emptied to the last drop in practice. A certain amount of residue evaporates before and is returned to the gas phase via the return line 16. The supply line 9 is thus cooled in the heat exchanger by the flowing back natural gas and supports the subsequent liquefaction. The gas in the return line 16 is heated and finally flows back into the pipeline 2. However, this presupposes that the working pressure in the cryogenic tank 13 is always higher than that in the pipeline 2, in which the evaporated natural gas is recycled. Depending on the situation, the pipeline pressure varies and therefore the system has to be adapted to this pressure. Failure to maintain the phase sense and storage tank pressure higher than the pipeline pressure requires a low pressure compressor in the return line. This must compress about 80% of the CNG volume supplied to the plant to push it back into the pipeline. For this purpose, an electric compressor can be used, which is however quite large and is then preferably housed in a separate container, because otherwise the space in the single container, otherwise the complete system would be housed, would be too much restricted for the storage tank.

The working pressure of Cryotankes 13 is up to 15 bar. at Exceeding the 15 bar by, for example, excessive heat, for example due to extreme heat and sunlight, opens the pressure relief valve and releases some gas into the atmosphere until the pressure has fallen back to the permissible level. At the mentioned capacity of 3050 liters, this tank has a length of 4640mm, a height of 1600mm and a diameter of 1350mm. Its empty weight is 2300 kg or 22563 N and its total weight at full tank about 3493 kg or 34266 N. It is understood that this mass may vary depending on capacity. Its inner shell is made of stainless steel, while the outer shell is made of carbon steel, treated with a suitable protective coating, which prevents corrosion and protects against mechanical damage. All supply and connection lines from the liquefaction station to the tank and from the same to the cryogenic pump are made of stainless steel. Due to the excellent isolation of the cryotank 13, which otherwise corresponds to a conventional cryotank, the evaporation rate is only 0.6% of the tank contents per day. At this cryotank 13, a bleed line 14 is connected below, which leads to a cryopump 15, by means of which a liquefied gas tank of a vehicle can be filled by a suitable line connection. The liquefied gas tank of the natural gas vehicle may have a few bar more than the working pressure of the cryotank 13 of up to 15 bar, and it has a pressure relief valve which opens at 16 bar. In practice, however, this hardly comes into function, because it is constantly driven and natural gas is taken from the tank. Only if a vehicle were to remain unused for weeks in the hot sun would one have to expect an increase in the tank pressure to over 16 bar. Because the pressure in the liquid tank of the vehicle to be refueled is generally higher than that in the cryotank 13, it is not possible to refuel from the cryotank 13 without a pump. The cryopump 15 conveys the liquid natural gas to up to 15 bar pressure in the liquefied gas tank of the vehicle. The cryopump 15 downstream delivery line is a flexible conduit with closure for tight connection to the liquid tank of a vehicle powered by LNG. As soon as liquid natural gas flows into a vehicle tank, which is almost empty and therefore contains gas at high pressure, the filled LNG is passed through the gas phase in the tank. As a result, the Gas phase together, the tank interior is cooled and the pressure is reduced again down to 5 bar. Such a cryopump 15 in the form of a piston pump for a delivery rate of 30 l / min at an input pressure of 1-5 bar and a delivery pressure of 16 bar absorbs about 2.34 kW of power and is operated at 380V / 50Hz high current. At its intake end at the cold end, the pressure during pumping is reduced to up to 1 bar.

This whole unit of all these above-mentioned components is preferably installed in a steel frame or in a standard container, which is then road transportable by being loaded onto a truck and can be delivered to the destination and there just needs to be parked. After connecting the supply line 9 to the compressor high-pressure line of the compressor of the CNG filling station and the connection of the return line 16 to the pipeline 2, the system is ready for operation.

Figure 2 shows a plant variant with a phase separator for the tank 24 separate storage tank 20 for the generated liquid natural gas. In contrast to the system according to FIG. 1, a total of three downstream high-pressure heat exchangers 21, 23, 22 are installed, the intermediate circuit including a cooling unit 23, instead of being cooled by the recirculation line 26. The supply line 9, after passing through the third heat exchanger 22, then leads to an injector 28 where the CNG is depressurized. This causes a massive cooling and in the course of the same takes place at a temperature of 135K (-138 ⁰ C), the phase change and a portion is liquefied. This LNG is then in the Phasenseparatortank 24, from which it is pressed at a pressure of 15 bar or more through the existing gas phase through the down-flowing Nachförderieitung 25, if necessary, in a separate cryogenic storage tank 20, in which the pressure is lower. Connected to this storage tank 20 is via a bleed line 14, in turn, a cryopump 15 for refueling a vehicle. The cryopump 15 downstream delivery line is a flexible conduit with closure for tight connection to the liquid tank of a vehicle powered by LNG. The line can also be used to fill a tanker or a separate storage tank for bunkering natural gas as LNG. From the phase separator tank 24, vaporized LNG flows via the return line 26 through the two heat exchangers 22,21, where it receives heat in two stages, first in the heat exchanger 22, then in the heat exchanger 21, and finally flows back into the pipeline 2. The in the cryogenic storage tank 20 vaporized LNG, on the other hand, can not return to the pipeline 2 by itself because of its lower pressure. For this reason, the gas phase is conducted from the storage tank 20 via a coupling line 27 into the injector 28. There, the gas is entrained by the gas flowing out through the high-speed gas discharge from the supply line 9 and gets back into the phase separator tank 24. This system is therefore without Joule-Thompson valve, but works only with an injector 28th

3 shows a plant variant with a separate also to the phase separator tank 24 storage tank 20 for the generated liquid natural gas. In contrast to the system according to FIG. 2, only one single high-pressure heat exchanger 40 is used instead of the three downstream heat exchangers and the cooling unit of the middle one. The supply line 9 leads after this heat exchanger 40 to an injector 28, where the CNG is released. As a result, the massive cooling takes place and in the course of the same occurs at a temperature of 135K (-138 ⁰ C), the phase change and a proportion is liquid natural gas. From the phase separator tank 24, vaporized LNG flows via the return line 26 through the single heat exchanger 40, where it absorbs heat, and finally flows back into the pipeline 2. The LNG evaporated in the cryogenic storage tank 20, by contrast, can not enter the pipeline by itself because of its lower pressure 2 back to flow. For this reason, the gas phase is conducted from the storage tank 20 via a coupling line 27 into the injector 28. There, the gas is entrained by the gas flowing out of the high-speed expansion gas from the supply line 9 and gets back into the phase separator tank 24. This system also comes without Joule-Thompson valve, but works only with an injector 28th The system of Figure 4 combines an injector with a Joule Thompson valve. It comes with a single high-pressure heat exchanger 30, and does not necessarily require a cooling unit. However, with a refrigeration unit, a higher efficiency is achieved for a 40% LNG yield from the CNG, rather than just 18%. This means that with slightly higher investment costs for an additional cooling unit you can approximately double the yield. From the compressor delivery line 8, the supply line 9 leads here first to a molecular sieve 11 for the elimination of CO ₂ and water. This is followed by an injector 38, in which a first relaxation of the gas takes place. The gas flows at a reduced pressure and already cooled by one stage through a heat exchanger 30 and gives off more heat. Then, it is passed through a Joule-Thompson valve 32, whereby it partially changes to the liquid phase and flows into the phase separator tank 33. Due to the gas phase pressure, the LNG is conveyed from this phase separator tank 33 by itself through the Nachförderleitung 35 in the separate storage tank 20, from then tapped via the bleed pipe 14 and the cryopump 15 and a vehicle can be refueled. The cryopump 15 downstream delivery line is a flexible conduit with closure for tight connection to the liquid tank of a vehicle powered by LNG.

FIG. 5 shows a further embodiment of the plant. It has a phase separator tank 24 and separate storage tank 20, and for liquefaction a vortex tube 39 is used, and further downstream is a downstream injector 28 for the actual liquefaction. The vortex tube and its functional principle was invented in 1930 and its function will be briefly explained here. Inside, a fluid revolves around the axis of the tube like a tornado, from which the word vortex is derived. As a result of the vortex generated by compressed air or gas, two separated gas streams are created inside the tube, one hot and one cold. The compressed air or compressed gas enters a cylindrical generator which is proportionately larger than the hot long pipe. The gas is thereby rotated. The rotating gas is then forced to flow along the inner walls of the hot tube downward, reaching high rotational speeds, up to 1OOO ¹ OOO rpm At the end, here at the lower end of the tube passes a small portion of this gas through a needle nozzle of -. the hot exhaust gas or Fall of hot air from hot exhaust air. The remaining gas must flow back in the center of the pipe in the opposite direction to the incoming gas, at a lower speed. In this case, heat is released from the slower flowing gas to the faster flowing, incoming gas. The afterwards super-cooled gas flow passes through the center of the generator and leaves it through a cold air outlet. By using such a vortex tube can be achieved with, for example, air to 6 bar, a temperature of -40 ° C on the cold side, and thus a liquefaction process can be drastically improved. The captivating properties of a vortex tube are that it does not contain any moving parts, that neither chemicals nor electrical energy are needed to achieve significant gas cooling, and that a vortex tube does not incur operating costs and maintenance costs. By exploiting the pressure reduction from a natural gas pipeline with an internal pressure of 50bar, which is then reduced to 5 bar, the cold side of a vortex tube can reach liquefaction temperatures for natural gas (LNG), ie -135 ° C and below, and that on memory pressures of 5 bar. Because of this, a vortex tube in a plant can replace a Chillier by using compressed air, increasing liquefaction efficiency by up to 40%. If the vortex pipe can even exploit the pressure reduction from a pipeline, then the liquefaction efficiency can even be increased by up to 100%, and without any special operating costs. When compressed air is used, the return air that has absorbed heat is released into the atmosphere. When natural gas is used, the hot gas is connected to the low pressure natural gas pipe. FIG. 5 shows such a system variant with a storage tank 20, which is likewise separate from the phase separator tank 24, for the liquid natural gas produced. In contrast to the other systems presented so far, a vortex tube 39 is used here to assist the liquefaction. The supply line 9 leads to a molecular sieve 11 by three series-connected heat exchangers 41, 42,43 and then to an injector 28, where the CNG is released. As a result, the massive cooling takes place and in the course of the same occurs at a temperature of 135K (-138 ⁰ C), the phase change and a proportion is liquid natural gas. From the phase separator tank 24, vaporized LNG flows via the return line 26 through the third heat exchanger 43, where it absorbs heat, and then through the first heat exchanger 41, and finally flows back into the pipeline 2. The LNG evaporated in the cryogenic storage tank 20, on the other hand, due to his lower pressure does not return to the pipeline 2 by itself. For this reason, the gas phase is conducted from the storage tank 20 via a coupling line 27 into the injector 28. There, the gas is entrained by the gas flowing out through the high-speed expansion gas from the supply line 9 and gets back into the phase separator tank 24. Essentially different from the previously presented systems is here a heat exchanger by means of the cold end of a vortex tube 39 is cooled. This vortex tube is fed by compressed air or compressed natural gas. The compressed gas flows tangentially in the center of the vortex tube into it creating a vortex in its interior, as described above for the function of a vortex tube. On the lower side, a small part of the compressed gas flows out at high temperature, and most of the incoming air is strongly cooled in the center of the vortex tube when flowing back, and appears here in the picture ob, on the cold side of the vortex tube , Vonr there is this cold gas, led to temperatures of up to -140 ⁰ C through the heat exchanger 42, where it absorbs heat, which is ultimately withdrawn from the supply of natural gas in the supply line. Thus, this natural gas is optimally conditioned for the subsequent liquefaction in the injector 28. This system is thus also without Joule-Thompson valve, but works only with a vortex tube 39 and an injector 28 for the liquefaction, and the associated heat exchangers 41, 42nd , 43rd

Because the whole system is housed in each version in a steel frame or container, which is equipped at its corners with lifting tabs, the system can be lifted for easy movement of a mobile crane and easily placed on site and connected afterwards become. The frame or container can measure in its outer dimensions, for example, W 243cm x H 260cm x L 915cm and is a Iso road transportable. If necessary, it can also be fixed to a trailer or a semi-trailer, so that the system can be moved very quickly. It is understood that the system can be built larger, but always it should be road transportable. The size of a unit is limited only by the road transport laws and regulations of each country. Downstream of the cryopump, the delivery line is a flexible conduit with closure for tight connection to the liquid tank of a LNG-powered vehicle. This system makes it possible to compact the filling station network for liquefied gas-powered vehicles very cost-effectively and quickly. It also makes it possible to quickly liquefy a considerable amount of natural gas for bunkering purposes, so that it is available in the event of bottlenecks. Such arise on the demand side, preferably in the cold season, but can also occur on the part of the provider through political machinations, but also as a result of natural disasters such as earthquakes, storm surges or hurricanes, or even as a result of terrorist or belligerent acts. The plant thus makes it possible to increase the security of supply with natural gas efficiently.

Claims

claims

1. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas, consisting of a frame or container, containing a supply line (9) for connecting the system to the compressor high-pressure line (8) of the compressor (3) of a CNG filling station, further comprising a compressed natural gas condensing device (CNG), a cryogenic phase separator and storage tank (13), and a motor-driven cryogenic pump (15) Tap line (14) with a delivery counter for connecting the same to the liquefied gas tank of a vehicle or tanker by the delivery line downstream of the cryopump (15) is a flexible conduit with closure for tight connection to a liquid tank.

2. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to claim 1, characterized in that the supply line (9) of the plant by a Verflüssigungsvoπichtung with a heat exchanger (10) and a downstream Joule-Thompson valve (12) is guided and thereafter in the cryogenic phase separator and storage tank (13), which consists of an inner shell made of stainless steel and an outer shell made of carbon steel with protective paint, and that from the phase separator and storage tank (13) a gas phase return line (16) from the phase separator and storage tank (13) through the heat exchanger (10) for heat absorption from the supply line (9) in the pipeline (2) returns (according to Figure 1).

3. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to one of claims 1 to 2, characterized in that the return line (16) the heat exchanger (10) by a low-pressure compressor (17) guided back into the pipeline (2) is (according to Figure 1).

4. Road transportable system for liquefying and caching of natural gas from a CNG filling station to a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to claim 1, characterized in that the supply line (9) of the plant by a liquefaction device leads, and is guided in detail by a first high-pressure heat exchanger (21), then by a downstream him second high-pressure heat exchanger with cooling unit (23) and thereafter by a third heat exchanger (22), and then by an injector (28) in a cryogenic phase separator tank (13) is guided, that a separate cryogenic storage tank (20) is present, which is fed by a down from the Phasenseparatortank (24) emptying Nachförderleitung (25) whose gas phase via a line (27) in the injector ( 28) is guided for liquefaction and recycling in the phase separator tank (24), and that a return line (26) f R is the gas phase from the Phasensepartortank (24) is recycled to a countercurrent direction to the feed line (9) first through the third heat exchanger (22) and thereafter through the first heat exchanger (21) in the pipeline (2) (according to Figure 2).

5. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to claim 1, characterized in that the supply line (9) of the plant by a liquefaction device by passing it through a heat exchanger (40) and then passing it through an injector (28) into a cryogenic phase separator tank (24) to provide a separate cryogenic storage tank (20) which extends through one of the bottom of the cryogenic storage tank (20) Phasesenseparatortank (24) feeding Nachförderleitung (25) is fed, and whose gas phase via a line (27) in the injector (28) is guided, for liquefaction and recycling in the Phasenseparatortank (24), and that a return line (26) for the Gas phase from the phase separator tank (24) in the counterflow direction to the supply line (9) is first returned by the heat exchanger (40) in the pipeline (2) (according to Figure 3).

6. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to claim 1, characterized in that the supply line (9) of the plant by a liquefaction device is guided, and in detail through an injector (38), then through a heat exchanger (30), and thereafter through a Joule-Thompson valve (32) in a cryogenic phase separator tank (33) that a separate cryogenic storage tank (20) is present, which is fed by a down from the Phasenseparatortank (33) opening Nachförderleitung (35) whose gas phase via a line (37) in the injector (38) is guided, for liquefaction and return to the supply line (9), and a gas-phase recirculation line (36) from the phase separator tank (33) in the counter-current direction to the supply line (9) through the heat exchanger (30) into the pipeline (2) is returned (Figure 4).

7. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to claim 1, characterized in that the supply line (9) of the system by at least one Heat exchanger (43), for the cooling of a vortex tube (39) is used, wherein a pressure line for natural gas or gas, the vortex tube (39) feeds and the gas exiting on the cold side through the heat exchanger (42) is guided , and the supply line (9) leads after this heat exchanger (42) through an injector (28) for liquefaction and then into a cryogenic Phasenseparatortank (24) that a separate cryogenic storage tank (20) is present, which by a bottom of the Phasesenseparatortank (24) feeding Nachförderleitung (25) is fed, the gas phase via a line (27) into the injector (28), for liquefaction and recycling in the Phasenseparatortank (24), and that a return line (26) for the gas phase from the phase separator tank (24) in the counterflow direction to the supply line (9) first by the third heat exchanger (43), then by the vortex tube cooled heat exchanger (42) and then returned by the first heat exchanger (41) in the pipeline (2) is (according to Figure 5).

8. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to one of the preceding claims, characterized in that the supply line (9) from the CNG Filling station is first passed through a molecular sieve (11) for the excretion of CO ₂ and water.

9. Road transportable system for liquefying and caching of natural gas from a CNG filling station on a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to one of the preceding claims, characterized in that it is installed in a 20ft container equipped with lifting tabs at its corners for easy shifting by means of a car crane, and that the phase separator and storage tank (13) has a length of 4640mm, a height of 1600mm and a diameter of 1350mm and a capacity of 3050 liters at a working pressure of up to 15 bar, and the associated cryopump has a capacity of at least 30 l / min.

10. Road transportable system for liquefying and caching of natural gas from a CNG filling station to a pipeline (2), and for refueling vehicles with the recovered liquid natural gas according to any one of the preceding claims, characterized in that the frame or the container in its outer masses W 243cm x H 260cm x up to L 1220cm and is therefore road transportable, and if necessary, firmly on a trailer or semi-trailer can be built, and the frame or container is equipped at its corners with lifting straps, for easy movement by means of a car crane.