FI123625B - Gas supply plant for a drive device and process for producing a gas mixture combustible in combustion engine - Google Patents

Description

A gas supply apparatus for a propulsion system and a method for producing a gas mixture to be burned in internal combustion engines

The invention relates to a gas supply apparatus 5 according to the preamble of claim 1 for an actuator for use with internal combustion engines. The invention further relates to a process according to the preamble of claim 19 for the preparation of a combustible mixture of Natural-Boil-Off gas and Forced-Boil-Off gas.

In gas tankers or other vehicles powered by natural gas 10, the natural gas is transported in a liquefied state whereby the temperature of the deep-cooled liquefied gas is about -162 ° C and its pressure is approximately atmospheric. The gas tanks, which are operable to receive transported deep-cooled liquefied natural gas, are heat-insulated expensive. However, a certain amount of warming of the supplied natural gas is unavoidable, which causes the gas in the deep-cooled liquefied natural gas (LNG) tank to evaporate into the tank as so-called Natural-Boil-Off gas. In order to counteract the increase in pressure in the gas tank containing the deep-cooled liquefied natural gas as a result of this inevitable evaporation, the Natural-Boil-Off gas is removed from the gas tank. 20 The same principle applies to solid, gas-fired, gas-fired liquefied-gas tanks.

From WO 2005/058692 A1, it is already known to supply natural gas, i.e. Natural-Boil-Off gas, which is vaporized by heating, to a gas consumer, in particular to a gas tanker for operating a natural gas-fueled gas. In addition, it is already known from this state of the art that, when the amount of Natural-Boil-Off gas is insufficient, deep-cooled

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The liquefied natural gas can be discharged from a gas container containing liquefied natural gas (LNG) and fed to a vaporizer.

30 Of a gas cylinder containing deep - chilled liquefied natural gas the removed natural gas is partially vaporized in the evaporator and, after evaporation, can be mixed with the so-called Forced-Boil-Off gas into the Natural-Boil-Off-g gas. This mixture of Natural-Boil-Off gas and Forced-Boil-Off gas can then be fed to the gas consumer, in particular to the drive unit used with 00 35 combustion engines. The non-volatile higher boiling components of natural gas are recycled back to the gas tank in unused hitherto known plants.

The composition of the mixture of Natural-Boil-Off gas and Forced-Boil-Off gas is subject to different conditions and is therefore subject to change. However, a mixture of natural-Boil-Off gas and Forced-Boil-Off gas 5 may only be burned in an internal combustion engine, such as a diesel or combustion engine drive unit, when it has a certain knocking strength. The so-called methane number of the alloy may be used as a measure of knocking strength, whereby this methane number approximates the ratio of methane to other components of the mixture of Natural-Boil-Off gas and Forced-Boil-Off gas 10. The methane number of an arbitrary gas mixture can be determined by a variety of commercially available devices.

However, it is not possible to produce an optimum knock-off mixture of Natural-Boil-Off gas and Forced-Boil-15 Off gas for actuator driven by hitherto known gas supply systems. Therefore, there is a need for a gas supply apparatus for an actuator driven by an internal combustion engine which can produce a mixture with optimum knock strength.

Henceforth, the present invention is based on the problem of creating a novel gas supply apparatus for an internal combustion engine actuator 20 and a novel method for producing a combustion engine combustible mixture of Natural-Boil-Off gas and Forced-Boil-Off gas.

This problem is solved by the gas supply apparatus according to claim 1. According to the invention, the gas supply apparatus comprises a tempering device for maintaining a substantially heavier, higher boiling hydrocarbon methane-poor, liquid natural gas concentrate at a defined temperature, wherein the defined temperature, liquid natural gas concentrate and deep-liquid condensate

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The removed, liquid natural gas can be contacted directly or indirectly in the evaporator in such a way that in the evaporator only about 30 methane is evaporated from the liquid natural gas.

| By means of the tempering device of the gas supply apparatus according to the invention, the liquefied natural gas consisting of substantially higher boiling hydrocarbons such as ethane, propane and butane! the injection is maintained at a specified temperature. In the flushing apparatus, this liquid natural gas concentrate, having a defined temperature of 0035, is contacted directly or indirectly with the liquid gas and the deep-cooled natural gas removed from the deep cooled liquefied gas reservoir. In this case, almost all of the methane is evaporated from the liquid natural gas, so that the Forced-Boil-Off gas produced in this way contains almost exclusively methane and virtually no heavier, higher boiling hydrocarbons.

Accordingly, it is an object of the present invention to make a natural gas concentrate of substantially heavier, higher boiling hydrocarbons and to use it for the partial vaporization of liquefied natural gas (LNG) removed from a tank containing deep-cooled liquefied natural gas. The evaporation of Melo Denmark, which is contained in liquid natural gas, is then almost bubble-free and drop-free. After mixing the Forced-Boil-Off gas thus produced with the Natural-Boil-Off gas, a mixture of Natural-Boil-Off gas and Forced-Boil-Off gas is optimal for knocking strength.

The process of the invention for producing a blend of natural-Boil-Off gas and Forced-Boil-Off gas in a combustion engine driven drive is defined in claim 19.

Preferred further developments of the invention will be apparent from the dependent claims and the following description. Exemplary embodiments of the invention will be described in more detail by way of the drawing, without being limited thereto. Then, Fig. 1 shows a gas supply apparatus according to the invention for an actuator for use with internal combustion engines according to a first embodiment of the invention;

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Fig. 4 is a gas supply apparatus according to the invention for a drive device for combustion engines according to a fourth embodiment of the invention,

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Figure 5 Gas supply apparatus according to the invention with internal combustion engines | 6 for the actuator according to the fifth embodiment of the invention, Fig. 6 for the actuator according to the invention for the actuator according to the sixth embodiment o and o 3 00 35 Fig. 7 for the actuator according to the invention according to the seventh embodiment of the invention.

The present invention relates to a gas supply apparatus for an actuator formed as an internal combustion engine, wherein the deep-cooled liquor as the propellant is contained in a container.

The gas supply apparatus according to the invention will now be described in more detail with reference to Figures 1-7, wherein Figures 1-7 each show various embodiments of the gas supply apparatus according to the invention.

Thus, Fig. 1 illustrates a first embodiment of a gas supply apparatus for an internal combustion engine actuator according to the invention, wherein the actuator is manufactured according to Fig. 1 from two engines 10. The gas supply apparatus 1 has two gas conduit systems.

Through the first gas pipeline system, so-called Natural-Boil-Off gas can be conducted in the direction of the motors 10. Natural-Boil-Off gas is produced by evaporation of liquefied natural gas (LPG) stored in a gas tank containing deep-cooled liquefied natural gas (11), liquefied natural gas and deep-cooled natural gas (12), a tank containing deep-cooled liquefied natural gas through a first gas pipeline system 13. Through the compressors 14 connected to the gas line 20 13, the Natural-Boil-Off gas can be supplied to the internal combustion engines 10, whereby downstream valves 15 of the compressors 14 prevent the return of the condensed Natural-Boil-Off gas back to the liquefied natural gas 11.

Where the amount of Natural-Boil-Off gas is not sufficient for the propulsion of a gasoline-engine-driven 25-liter LPG, another gas pipeline system will provide 12 LPGs to be removed from the LPG and 12 LNGs.

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^ can be fed to the vaporizer of the gas supply system. In the vaporizer 16 °, the liquid liquefied natural gas (LNG) taken from a gas reservoir containing liquefied natural gas (LNG) 11 can be evaporated and mixed, so called | Forced-Boil-Off gas through mixing point 17 with Natural-Boil-Off gas. A second non-return valve 15 prevents return flow to the evaporator in the direction of 16 g.

o Downstream of the mixer 17 there is accordingly a mixture of Natural-Boil-Off-00 35 gas and Forced-Boil-Off gas, which is heat-tempered in the heat exchanger 18, preferably at room temperature, and subsequently fed to the gas control step 19 or the motors 10. The mixture of Boil-Off gas and Forced-Boil-Off gas is preferably burned in a safety device 20 formed as an oxidant.

In the embodiment of Figure 1, the evaporator 16 maintains a predetermined amount of methane-poor, liquid natural gas concentrate 21, wherein the liquid natural gas concentrate 21 consists essentially of heavier, higher boiling components of natural gas, primarily hydrocarbons ethane, propane and butane. By means of the tempering device 22, this methane-poor liquid natural gas concentrate 21 is maintained at a specified temperature, whereby the liquid natural gas component 21 of defined temperature 10 in the vaporizer 16 is introduced into a liquefied liquid-liquefied liquid and liquefied liquor 12. In this case, methane is vaporized almost exclusively from the liquid natural gas, which is then discharged as Forced-Boil-Off gas from the evaporator 10 and 15 to a mixing point 17 with Natural-Boil-Off gas.

In the exemplary embodiment of Figure 1, the evaporator 16 has a collecting member 23 for a methane-poor, liquid natural gas concentrate 21, wherein the tempering device 22 is disposed within the collecting member 23 and holds the natural gas concentrate 11 in the evaporator 16. Liquid natural gas 12 brought into contact with this natural gas seal 21 is removed by pump 24 from a gas reservoir containing liquefied natural gas 11 and fed through a pipeline 25 of a second gas pipeline system to a vaporizer 16. A non-return valve 26 prevents the gas from being exhausted.

The tempering device 22 maintains the methane-poor, liquid natural gas concentrate 21 at approximately constant temperature, whereby this temperature is dependent upon the overall composition of the ai-5 natural gas concentrate and the liquid natural gas concentrate.

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the vapor pressure of the methane contained in the mouth 12 at the desired operating temperature within the vaporizer 16.

30 In the embodiment of Figure 1, deep-cooled liquefied natural gas the deep-cooled and liquid natural gas 12 removed from the gas reservoir containing mouth 11 is contacted by injection nozzles 27a directly with the tempered natural gas concentrate 21 o maintained in the collecting section 23 of the vaporizer 16, namely by directing the from natural gas. The evaporation of methane from natural gas must be so bubble-free and drip-free that no heavier, higher-boiling hydrocarbons can reach the Forced-Boil-Off gas.

In the evaporator 16, the non-evaporated liquefied natural gas components are collected in the collector tank 23 of the evaporator 16, thereby increasing the amount of methane-poor natural gas concentrate 21 retained in the evaporator 16. By means of the level control device 28, the amount of natural gas concentrate 21 retained in the evaporator 16 is monitored, whereby when there is too much natural gas concentrate in the evaporator 16, Prior to introducing the natural gas concentrate thus removed, it is cooled in a heat exchanger 30 to a gas container containing liquefied natural gas 11, through which, also via pipeline 25, a liquefied natural gas obtained from a gas container containing liquefied natural gas 11 is passed. The mu-15 level control device 28 of Figure 1, depending on the amount of natural gas seal 21 in the collection section 23 of the evaporator 16, opens a valve 31 integrated downstream from the heat exchanger 30 to the return line 29.

The pressure transducer 32 measures the pressure of the Forced-Boil-Off gas, whereby, depending on this pressure, the valve 33 integrated in the pipeline 25 can be opened and 20 closed. With decreasing pressure, the pressure transducer 32 opens more than the valve and directs more liquid natural gas into the evaporator 16 in the direction toward it. Conversely, if the pressure in the pressure transducer 32 rises, the valve 33 will be closed more.

In the embodiment of Fig. 1, downstream of valve 33 in the conduit 25 of the ka-25, a pressure equalization tank 34 is provided to compensate for pressure variations. When valve 33 allows less liquid earth gas 5 to pass through than pump 24, liquid natural gas is fed to valve 35

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via the pressure equalization tank 34. The pressure sensor 36 monitors the pressure in the pressure equalization tank 34 and the fill level sensor 37 monitors the filling level of the pressure equalization tank 34, so that when the pressure and / or degree of filling of the pressure equalization tank 34 is exceeded. When these limits are reached, the pump 34 is switched off. Conversely, if the limit values are lowered, the shut-down pump 24 can be switched on, in addition to a small amount of liquid natural gas and vaporized natural gas, preferably filled with an inert gas such as a inert gas in the pressure equalization tank 34. can be adjusted by the valves 38, 39. The valve 38 then acts to supply an inert gas from the inert gas system to the pressure relief tank 34. The valve 39, by contrast, operates to deflate the inert gas out of the pressure relief tank 34.

Downstream of the heat exchanger 18, a methane number sensor 40 is fitted, whereby the methane number of a mixture of Natural-Boil-Off-5 gas and Forced-Boil-Off gas can be measured by means of a methane number sensor 40. The methane number sensor transmits the corresponding actual value of the methane number to the control device 41.

Depending on the measured actual value and the preset value, the regulator 41 controls the valve 42 fitted to the tempering device 22 and thus the tempering device 22 in such a way that the temperature of the natural gas seal 21 already prepared in the collecting section 23 10 of the evaporator 16 is adjusted. The temperature of the natural gas seal already in the collection vessel 23 is then monitored by means of the temperature sensor 43, whereby the temperature sensor 43 transmits the corresponding actual value to the control device 41.

According to Fig. 1, droplet separator 15 44 is integrated into the vaporizer 16 by means of a drop separator 44 for removing heavier, higher boiling hydrocarbons . In addition, as shown in Figure 1, a defoamer 45 20 is integrated in the evaporator 16 to remove foam bubbles from the evaporated methane.

Figures 2-7 illustrate other embodiments of the gas supply apparatus for the actuator for use with internal combustion engines according to the invention, the same reference numerals being used for the same subassemblies to avoid unnecessary repetitions, and only the details of Figures 2-7 differing from

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Thus, the embodiment of Fig. 7 differs from the embodiment of Fig. 1

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^ only for connection of the pressure relief tank 34 to the second pipeline 25 of the gas supply system.

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Thus, in the embodiment of Figure 1, the pressure equalization tank 34 is connected | on the other hand, two valves 46 are connected between the gas line 25 and the pressure relief tank 34, whereby in the embodiment of Figure 7, the liquid vaporizable in the vaporizing device 16 is continuously flowing through the evaporator 12 Accordingly, in the embodiment of Figure 7, the liquid natural gas 12 discharged from the gas reservoir containing deep-liquefied natural gas 11 can only be fed through the pressure relief tank 34 to the evaporator 16. By contrast, in the embodiment of Figure 1, the liquor pressure relief tank 34 for vaporizer 16.

7, a second valve 47 can be used to set a bypass between the pressure equalization tank 34 and the gas line 29 to conduct liquid natural gas by bypassing the evaporator 16 from the pressure equalization tank 34 back to the deep-cooled liquefied natural gas (11).

It is common to the embodiments of Figs.

In contrast, Figure 2 illustrates an embodiment of a gas supply apparatus 15 in which liquid and deep-cooled natural gas 12 removed from a gas container containing liquefied natural gas 11 is injected from above onto the natural gas seal 21. With respect to all other details, the embodiment of Fig. 2 corresponds to the embodiment of Fig. 1.

Figure 3 illustrates a modification of the embodiment of Figure 2, wherein at least one filler 48 is integrated into the vaporizer 16 of the gas supply apparatus of the invention in the embodiment 20 of Figure 3. on top of the natural gas concentrate 21, but on the contrary, first on the filler 25 or each filler 48, whereby the liquid natural gas injected onto the filler or each filler 48 forms liquid films on the surfaces of the filler or 5 of each filler 48

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indirectly in contact with the ready tempered natural gas seal 21 in the collection section 23 of the evaporator 16. As LPG drips onto the surface of the natural gas concentrate, methane vaporises, leaving | the rising methane passes through the liquid film formed on the filler material or on each filler material 48, whereby the sealing droplets introduced in the gaseous methane stream g are separated on these liquid films.

Another embodiment of the gas supply apparatus according to the invention is illustrated in FIG. In addition, the ready-to-hold 5 and the tempered natural gas seal 21 held in the evaporator assembly 23 and the tempered natural gas seal 21 can be removed by pump 50 from the evaporator 16 assembly 23 and fed to the spray nozzles 49 in rotation or rotation. 4, a valve 52 is integrated in the circulating pipe 61 leading to the spray nozzles 49, which is controlled by the regulator 41. In addition, a temperature sensor 53 is coupled to the circulating pipe 51 for immediately detecting the temperature of the natural gas concentrate.

Accordingly, in the embodiment of Figure 4, a partially vaporizable liquid natural gas 12 and a methane-poor tempered natural gas concentrate 21 are sprayed on top of the filler or any filler 48 from the top via spray nozzles. Thereby, heat transfer occurs between the liquid films formed on the surfaces of the filler material or each of the filler material 48 so that the volatile methane flows upward, while the natural gas seal 21 and the non-volatile gas components 12

As an alternative to this, in the embodiment of Figure 4, the surfaces of the filler or each filler 48 may be sprayed in separated areas with partially vaporizing, liquid natural gas and tempered natural gas concentrate, whereby the filler or each filler , liquid natural gas is mixed with the tempered natural gas-o concentrate. In this case, mixing only takes place in the collecting section 23

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^ in the area of the surface of the seal.

Another embodiment ^ 30 of the gas supply apparatus according to the invention is illustrated in Fig. 5, wherein the embodiment of Fig. 5 corresponds substantially to Fig. 4 | an exemplary embodiment. However, in the embodiment of Fig. 5, unlike the embodiments described above, the tempering device 22 is not configured such that N? thus, steam outside the apparatus 16. In addition, a tempering device 22, which is formed as a heat exchanger in FIG.

In order to prevent the natural gas seal 21 from evaporating on heating inside the heat exchanger 22, a higher pressure is applied to the circulation pipe 51 via the pump 50 and the valve 52 than in the evaporator 16. The heated 5 and pressure-loaded natural gas 21 are Thus, the efficiency of the gas supply apparatus is clearly increased.

Another embodiment of the gas feeding apparatus according to the invention is shown in Figure 6. In the embodiment of Figure 6, in accordance with the embodiment of Figures 1 and 7 10, the liquid NATURAL GAS! onto the filler or each filler 48, only 15 tempered methane-poor natural gas concentrates 21 are sprayed on spray nozzles 49. or on top of each filler 48.

As already mentioned many times, the deep-cooled natural gas 12 removed from the gas reservoir containing liquefied natural gas 11 is fed to the evaporator 16, whereby this natural gas and the tempered natural gas concentrate 21 are contacted as defined. The temperature of the deep-cooled natural gas 12 after the heat exchanger 30 is about -144 ° C, the temperature of the tempered natural gas seal 21 is about -80 ° C. The corresponding composition of the natural gas concentrate then guarantees that the pressure in the evaporator 165 does not exceed about 6.5 bar (absolute). The heating medium 22 of the tempering device 22

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Frost protection down to about -80 ° C is sufficient to operate the evaporator 16.

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The gas supply apparatus according to the invention also includes such embodiments forms are conceivable in which the features of the disclosed embodiments are partially or completely combined. Thus, also in the embodiments of Figures 2-6, the pressure equalization tank 34, in accordance with the embodiment of Figure 7, can be connected to the gas line 25 in such a way that natural gas 12 removed from the tank containing liquefied natural gas 11 is permanently flowing through it.

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It is likewise conceivable to combine Figures 5 and 6 so as to use only the exterior heat exchangers. The liquid natural gas 12 fed through the heat transfer of the circulating natural gas concentrate 21 in the evaporator 16 is raised in temperature while simultaneously increasing the temperature-5 difference in the external heat exchanger 22.

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Claims (20)

A gas supply system for a drive device operated by internal combustion engines (10) with a first gas line system (13), through which a gas container (11) containing frozen frozen condensed gas (12) can be measured for ground gas which is expanded on the basis of a heating system. the container as Natural-Boil-Off gas in the direction of the drive device, and with a second gas piping system (25), through which when the amount of Natural-Boil-Off gas is not sufficient for the drive device liquid soil gas can be removed from the gas container (11) containing frozen condensed natural gas, measured in an extinguishing device 10 (16) and after partial displacement, is mixed as Forced-Boil-Off gas with Natural-Boil-Off gas for feeding a mixture consisting of Natural-Boil-Off-gas and Forced-Boil Off-gas in the direction of the driving device, characterized by a tempering device (22) for holding a methane-low, liquefied natural gas concentrate consisting of relative to the methane even heavier higher-boiling hydrocarbons at a defined temperature, whereby the liquefied natural gas concentrate (21) at a defined temperature and the liquefied natural gas (12) removed from the gas container containing deep-frozen condensed natural gas (11) can be brought into the extension device (16) in a direct or indirect manner, in contact with the extinguishing device (16), methane 20 is almost exclusively extinguished from the liquefied natural gas. Gas supply plant according to claim 1, characterized in that the tempering device (22) pours the methane-low liquefied natural gas concentrate at a predetermined temperature, said temperature being dependent at least on the composition of the gas mixture and the displacement pressure of methane contained in the liquid. the ground gas at the desired operating temperature of the closure device (16). 3. Gas supply device according to claim 1 or 2, characterized in that in the extinguishing device (16) the co-non-extensible components of the liquefied natural gas can be measured in the concentrate. x 30 Gas supply device according to any one or more of claims 1 - 3, characterized in that the extinguishing device (16) comprises a draggle separator (44) for separating drops from methane which is diluted in the extinguishing device (16) and thus from the forced valve. Boil-Off gas from heavier, higher-boiling hydrocarbons, the drip separator (44) being arranged below the outlet of the exchanger (16). 17 Gas supply plant according to any of Claims 1 to 4, characterized by the evaporator device (16) having a collection part (23) for methane-poor, liquid soil gas concentrate, whereby liquid soil gas removed from the gas container containing frozen frozen condensed gas (11) directly contacted with the natural gas concentrate collected in the collection part (23). Gas supply plant according to claim 5, characterized in that the evaporator (16) comprises injection nozzles (27a) for conducting liquid soil gas taken from the gas container containing frozen condensed natural gas (11) with a high impulse to the soil gas concentrate (collected in 23). ) and having a defined temperature. Gas supply plant according to Claim 5 or 6, characterized in that liquid soil gas removed from the gas container containing frozen condensed natural gas (11) can be sprayed via injection nozzles 15 (27b) from above and / or from below the top of the collection gas collection tank (16). (23). Gas supply plant according to any one or more of claims 5 to 7, characterized in that a level control device (28) is arranged in the collection part (23) of the extinguishing device to pour the amount of soil gas concentrate approximately constant into the collection part (23), there is too much ground gas concentrate in the collection section, the level control device leads the excess ground gas concentrate after cooling back to the gas container containing frozen condensed natural gas (11). Gas supply plant according to any one or more of claims 1 to 8, characterized in that in the displacement device (16) there is at least one filler (48). Gas supply plant according to claim 9, characterized in that soil gas removed from the container containing frozen condensed natural gas (11) can be sprayed via the injection nozzles (27b) of the filler or any filler (48). the ground gas forms on the filler | or liquid surfaces of each filler and from there can be indirectly brought into contact with the concentrate. Gas supply plant according to claim 9, characterized in that liquid soil gas removed from the gas container containing deep frozen condensed natural gas (11) and the concentrate can be sprayed via different injection nozzles (27, 49) on top of the filler or each filler (48). . 18 Gas supply plant according to any one or more of claims 1-11, characterized in that the extinguishing device (16) comprises a foam remover (45) for removing foam bubbles from the methane which is displaced in the extinguishing device (16) and thus from the Forced-Boil-Off gas. Gas supply plant according to any of the claims 1-12, characterized by a control device specifically for controlling the amount of liquid soil gas to be removed from the gas container containing frozen condensed natural gas and which is partially extended in the extension device depending on the amount of Natural-Boil-Off gas. which is to be measured in the driver (10). Gas supply plant according to any of the claims 1-13, characterized by a metal number sensor (40) downstream of a mixing point (17) serving a mixture of Natural-Boil-Off gas and Forced-Boil-Off -gas measures the mixture's metal number and conveys a corresponding real value to the control device (41) to adjust the medium-low liquid gas concentrate temperature. Gas supply plant according to any of claims 1 to 14, characterized in that liquefied natural gas can be removed from the gas container containing frozen condensed natural gas (11) with a pump (24) and measured to the extinguishing device (16), in the closing device (26) can be controlled by the pump (24). Gas supply plant according to any of the claims 1-15, characterized by a pressure equalization container (34) connected between the gas container containing frozen condensed natural gas (11) and the displacement device (16) for equalizing pressure variations. Gas supply plant according to any one or more of claims 1-16, characterized in that downstream of the mixing point CNJ surface (17) serving the mixture of Natural-Boil-Off gas and Forced-Boil-Off gas ° has a heat exchanger (18) is provided for tempering the mixture to be measured at CO 30 in the drive (10) and in particular downstream of the relative til | the heat exchanger measures the metric number sensor of the mixture's metric number. 18. Gas supply device according to claim 17, characterized in that a safety device (20) specially designed as an oxidant-designed safety device (20) is coupled between the heat exchanger (18) and the drive device (10) to lead away the mixture consisting of Natural-Boil-Off. gas and Forced-Boil-Off gas, especially for combustion. 19 A process for producing a mixture consisting of Nautical-Boil-Off gas and Forced-Boil-Off gas to be combusted in internal combustion engines (10), wherein in a gas container (11) containing frozen liquefied natural gas ( 12) measure ground gas evaporated on the basis of heating in the container as Natural-Boil-Off gas in the direction of a drive, where when the amount of Natural-Boil-Off gas is insufficient for the floating device, liquid natural gas is removed from the gas container (11) containing frozen frozen condensed natural gas (12), measured in a displacement device (16) and after partial displacement is mixed as Forced-Boil-Off gas with Natural-Boil-Off gas, known as -10. a methane-low liquid liquefied natural gas concentrate (21) consisting of substantially heavier right boiling hydrocarbons is poured at a defined temperature, the liquid liquefied natural gas concentrate (21) having the defined temperature and the the holder removed liquid soil gas (12) containing frozen frozen condensed gas (11) is brought into contact with the locking device (16) directly or indirectly, in the locking device (16), almost only methane from the liquid ground gas is extended. The method according to claim 19, characterized by the features according to any one or more of claims 1-18. CO δ (M m o CO X cc CL N- f'- σ> o n- o o C \ J