System for supplying gas to at least one gas-consuming apparatus of a floating structure

Abstract

The present invention relates to a system (1) for supplying gas to at least one gas-consuming apparatus (2, 2a, 2b), the system comprising: - a tank (3), - a supply circuit (4) comprising a first compression device (5), - a reliquefaction line (6) comprising a second compression device (8), - a cooling circuit (10) comprising a pumping device (13), the supply system (1) comprising a first heat exchanger (9), characterized in that the supply system (1) comprises a secondary reservoir (11), the supply system (1) comprising a supply line (12) configured to collect gas in the vapour state from the secondary reservoir (11), the pumping device (13) being configured to collect the gas in the liquid state contained in the secondary reservoir (11).

Description

[0001] DESCRIPTION

[0002] Title of the invention: Gas supply system for at least one gas-consuming device of a floating structure

[0003] The present invention relates to the field of floating structures for storing and / or transporting gas in the liquid state and more particularly concerns a gas supply system for at least one gas-consuming device included within such floating structures, said supply system comprising at least one membrane tank configured to transport and / or store the gas.

[0004] During a journey made by a floating structure transporting and / or storing gas in the liquid state intended to be consumed and / or delivered to a destination point, said floating structure may be able to use at least part of said gas in the liquid state in order to supply at least one of its gas-consuming devices, via a gas supply system.

[0005] Generally speaking, it is known that this type of supply system allows consumption of the gas that has evaporated within the tank in order to supply the gas-consuming device. Such evaporation can occur following an overall increase in the temperature of the tank over time and the gas in the vapor state generated must be evacuated in order to avoid overpressure of the tank.

[0006] When the gas in the vapor state is present in an excessive quantity in the tank compared to the needs of the gas consuming device, the excess gas in the vapor state can be reliquefied using this same supply system in order to avoid wasting the gas in the vapor state by burning it or releasing it into the atmosphere. In addition, when the gas in the vapor state is present in too small a quantity to meet the supply needs of the gas consuming device, the supply system can also address this problem by taking gas in the liquid state from the tank and evaporating it before sending it to the gas consuming device.

[0007] The process of gas consumption by the consumer device, whether from the gas in the vapor state generated in the tank or from the gas in the liquid state taken from it, necessarily involves a withdrawal from the tank. However, this necessarily results in a loss of quantity of gas present in said tank, which can prove problematic in the case where the gas cargo is intended to be delivered to a destination point, knowing that the loss can be significant depending on various parameters such as the duration of the journey.

[0008] The present invention optimally limits the extraction of gas from a cargo intended to be delivered by proposing a gas supply system for at least one gas-consuming device of a floating structure, the supply system comprising: at least one membrane tank configured to contain the gas, at least one gas supply circuit for the gas-consuming device, comprising at least one first compression device configured to compress gas extracted in the vapor state from the tank to a pressure compatible with the needs of the gas-consuming device, at least one line for reliquefying the gas in the vapor state, the reliquefaction line being connected to the supply circuit at a point of divergence arranged between the tank and the first compression device, the reliquefaction line comprising a second compression device,at least one cooling circuit comprising at least one pumping device configured to draw gas in the liquid state, the supply system comprising a first heat exchanger configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line downstream of the second compression device and the gas in the liquid state circulating in the cooling circuit, characterized in that the supply system comprises a secondary tank with self-supporting walls configured to contain gas in the liquid state, said supply system comprising a supply line configured to draw gas in the vapor state from the secondary tank, the supply line being connected to the supply circuit, the pumping device of the cooling circuit being configured to draw the gas in the liquid state contained in the secondary tank.,

[0009] By means of the supply system according to the invention, the gas used to supply the gas-consuming device is taken as a priority from the secondary tank, which is dedicated to supplying gas to the gas-consuming device, while the gas contained in the membrane tank, which constitutes a cargo intended to be delivered to a destination point, is only taken to supply the gas-consuming device when absolutely necessary. This optimally limits the extraction of gas from the cargo and thus ensures delivery of the required quantity of gas to the destination point.

[0010] The membrane tank is the vessel containing the liquid gas cargo to be delivered to the destination point. Such a tank has a plurality of membranes and walls that provide both sealing and thermal insulation, thus limiting the natural evaporation of the liquid gas.

[0011] The supply circuit allows the gas-consuming appliance to be supplied with gas in the vapor state taken from the tank. It is understood from the above that the gas in the vapor state contained in the tank is only used as a last resort to supply the gas-consuming appliance, the gas in the vapor state present in the secondary tank being used as a priority to supply the gas-consuming appliance.

[0012] The first compression device is configured both to suck in the gas in vapor state contained in the tank and to raise it to a pressure ensuring its optimal consumption by the gas-consuming device.

[0013] The reliquefaction line allows the gas in the vapor state present in the tank to pass into the liquid state. Preferably, all of the gas forming in the vapor state in the tank circulates in this reliquefaction line in order to be reliquefied. Thus, an identical or substantially identical volume of gas from the cargo intended to be delivered is retained. Since the point of divergence is located between the tank and the first compression device, the latter cannot perform its function of suction and pressure increase of the gas in the vapor state in order to circulate it in the reliquefaction line. This is why the second compression device must be arranged at the reliquefaction line in order to perform these functions. The supply circuit and the reliquefaction line are therefore separated and two separate compression devices are installed.

[0014] In order to avoid any waste of gas, it is important to know the precise quantity of gas in the vapor state that is sent to the gas-consuming device and therefore that is compressed by the first compression device. Implementing a compression device common to the supply circuit and the reliquefaction line complicates the calculation of this quantity sent to the gas-consuming device. In order to limit as much as possible a potential excess of gas in the vapor state sent to the gas-consuming device unnecessarily, it is advantageous to carry out a compression of the gas in the vapor state intended to be consumed by the gas-consuming device independently of a compression of the gas intended to be reliquefied.

[0015] In order to ensure the reliquefaction of the gas in the vapor state, the reliquefaction line passes through the first heat exchanger. The gas in the vapor state circulating in the reliquefaction line is therefore cooled while circulating within this first heat exchanger. Such cooling results in at least partial reliquefaction of the gas circulating in the reliquefaction line.

[0016] The cooling circuit also passes through the first heat exchanger and the liquid gas circulates within this same cooling circuit. The liquid gas circulating in the cooling circuit is at a lower temperature than the vapor gas circulating in the reliquefaction line. The first heat exchanger therefore allows the vapor gas circulating in the reliquefaction line to be cooled by the liquid gas circulating in the cooling circuit. According to one example, the liquid gas can be taken by the pumping device in the tank. The secondary tank differs from the membrane tank in that it has self-supporting walls. The secondary tank can thus withstand higher overpressure than the membrane tank, which allows the vapor gas to accumulate. The secondary tank also has a smaller volume than the membrane tank.

[0017] Just like the tank, the secondary tank contains thermally insulated gas in a liquid state. A secondary tank canopy also contains gas in a vapor state. As mentioned previously, the role of the gas contained in the secondary tank is to supply the gas-consuming device in place of the gas contained in the tank, whenever possible. Advantageously, during a journey made by the floating structure, the gas-consuming device is supplied entirely by the gas in a vapor state contained in the secondary tank and at no time by the gas in a vapor state contained in the tank, the latter being entirely reliquefied via the reliquefaction line.

[0018] The supply line allows the secondary tank to be fluidically connected to the supply circuit. Advantageously, the supply line is connected to the supply circuit upstream of the compression device relative to a direction of circulation of the gas in the vapor state intended to supply the gas-consuming device. This avoids the need to use a compression device exclusive to the supply line. Thus, the gas in the vapor state contained in the secondary tank can join the supply circuit, be sucked in by the first compression device and be raised to the pressure compatible with the gas-consuming device to supply the latter.

[0019] Advantageously, the gas is taken from the secondary tank in the liquid state to circulate in the cooling circuit. The pumping device is therefore fluidically connected to the secondary tank and pumps the gas in the liquid state contained within it. This avoids pumping gas in the liquid state into the tank and disturbing the temperature of the latter by using it as a means of reliquefaction for the gas in the vapor state. Thus, in an ideal configuration, only the fraction of gas leaving the tank is intended to be completely reliquefied. The volume of cargo stored in the tank is therefore ideally never lost.

[0020] The pumping device can be arranged within an internal volume of the secondary tank or outside it. The advantage of arranging the pumping device within the secondary tank is to limit the spatial footprint of the supply system.

[0021] According to a feature of the invention, the cooling circuit extends to the secondary tank. After its circulation within the first exchanger to cool the gas in the vapor state circulating in the reliquefaction line, the gas in the liquid state circulating in the cooling circuit circulates until it returns to the secondary tank. The gas in the liquid state can therefore be reused for subsequent cooling of the gas in the vapor state.

[0022] Furthermore, due to its circulation within the first heat exchanger, the liquid gas circulating in the cooling circuit increases in temperature. Its return to the secondary tank at a higher temperature therefore promotes the generation of gas in the vapor state within the secondary tank, thus providing a greater quantity of fuel to supply the gas-consuming device via the supply line.

[0023] According to a feature of the invention, the supply system comprises an evaporation line connected to the cooling circuit downstream of the first heat exchanger and extending to the supply circuit downstream of the first compression device, the supply system comprising an evaporation device configured to evaporate the gas circulating in the evaporation line. Instead of returning to the secondary tank, the gas in the liquid state circulating in the cooling circuit and having passed through the first heat exchanger can be directly used to supply the gas-consuming device by circulating within the evaporation line instead of continuing its circulation in the cooling circuit until returning to the secondary tank. Such a configuration is also implemented as a priority compared to a supply of the gas-consuming device via the gas in the vapor state contained in the tank.

[0024] Since the gas consuming device only tolerates gas in the vapor state, the gas in the liquid state circulating in the evaporation line must first be evaporated before being sent to the gas consuming device. The evaporation device ensures evaporation, for example, via a heat exchange with a third-party fluid such as seawater. The evaporated gas then circulates to the gas consuming device to supply it. It is not necessary for the evaporated gas to pass through the first compression device because the evaporated gas has already been previously raised to a pressure compatible with the gas consuming device by being pumped by the pumping device during its circulation in the liquid state. Advantageously, the pumping device therefore allows a rise in gas pressure equivalent to that of the first compression device.

[0025] According to a characteristic of the invention, the first heat exchanger is configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line downstream of the second compression device, the gas in the liquid state circulating in the cooling circuit, and the gas in the vapor state circulating in the supply line. This is an alternative to the supply system ensuring the circulation of three gas flows within the first heat exchanger in order to improve the reliquefaction of the gas in the vapor state circulating within the reliquefaction line.

[0026] Indeed, the gas in the vapor state coming from the secondary tank has a sufficiently low temperature to be able to participate in the reliquefaction of the gas in the vapor state circulating in the reliquefaction line. In such a configuration, when the gas in the vapor state circulating in the reliquefaction line passes through the first heat exchanger, said gas is cooled both by the gas in the liquid state circulating in the cooling circuit and by the gas in the vapor state circulating in the supply line.

[0027] According to a characteristic of the invention, the supply system comprises a second heat exchanger configured to carry out a heat exchange at least between the gas in the vapor state circulating in the reliquefaction line between the divergence point and the second compression device and the gas in the vapor state circulating in the reliquefaction line between the second compression device and the first heat exchanger.

[0028] The second heat exchanger is a heat exchanger internal to the lines where the gas in the vapor state intended to be reliquefied circulates. The second heat exchanger is a heat exchanger within which two gas flows circulate. The second heat exchanger allows precooling of the gas in the vapor state compressed by the second compression device and subsequently circulating within the first heat exchanger. Such precooling facilitates reliquefaction within the first heat exchanger subsequently.

[0029] The pre-cooling of the gas in the vapor state circulating in the reliquefaction line between the second compression device and the first heat exchanger is done using the gas in the vapor state coming directly from the tank and circulating in the reliquefaction line. Not having yet been compressed by the second compression device, said gas is therefore at a lower temperature than the compressed gas in the vapor state which is therefore cooled by heat exchange.

[0030] According to a feature of the invention, the feed system comprises a separator provided with an inlet, a liquid outlet and a vapor outlet, the reliquefaction line extending to the inlet of the separator. As mentioned previously, the gas circulating in the reliquefaction line leaves the first heat exchanger at least partially reliquefied. The gas is thus in a two-phase state, that is to say it comprises a fraction in the liquid state and a fraction in the vapor state. The gas in the two-phase state then circulates until it enters the separator where the liquid and gaseous fractions are separated. It is entirely possible for the gas leaving the first heat exchanger to leave entirely in the liquid state, in which case the gas is not divided into two fractions within the separator.

[0031] According to a feature of the invention, the supply system comprises a vapor gas return line connected to the vapor outlet of the separator and extending at least as far as the reliquefaction line between the point of divergence and the second heat exchanger. The vapor gas fraction separated by the separator constitutes the gas fraction that has not reliquefied after circulation within the first heat exchanger. This vapor gas fraction recirculates to the reliquefaction line, upstream of the second heat exchanger, via the vapor gas return line after exiting the separator via the vapor outlet. It should be noted that the vapor gas return line may also be connected to the supply circuit or to the supply line in order to be able to use the vapor gas fraction separated by the separator as fuel for the gas-consuming appliance.

[0032] According to an alternative feature of the invention, the supply system comprises a vapor gas return line connected to the vapor outlet of the separator and extending to the reliquefaction line between the second heat exchanger and the second compression device, the second heat exchanger being configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line between the divergence point and the second compression device, the gas in the vapor state circulating in the reliquefaction line between the second compression device and the first heat exchanger, and the gas in the vapor state circulating in the vapor gas return line.

[0033] Such an alternative also allows the vapor gas fraction separated by the separator to reach the reliquefaction line, but by first passing through the second heat exchanger, which in this configuration is then a heat exchanger within which three gas flows circulate. In this configuration, the vapor gas circulating in the vapor gas return line thus also participates in the pre-cooling of the vapor gas compressed by the second compression device. The temperature of the vapor gas circulating in the vapor gas return line is also lower than the vapor gas compressed by the second compression device because the vapor gas circulating in the vapor gas return line has previously been cooled within the first heat exchanger.The vapor gas return line and the reliquefaction line subsequently join at the outlet of the second heat exchanger. According to a characteristic of the invention, the second heat exchanger is configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line between the point of divergence and the second compression device, the gas in the vapor state circulating in the reliquefaction line between the second compression device and the first heat exchanger, the gas in the vapor state circulating in the vapor gas return line, and the gas in the vapor state circulating in the supply circuit between a point of convergence at which the supply line is connected to the supply circuit, and the first compression device.Alternatively, the second heat exchanger can therefore comprise four passes where four gas flows circulate, three of which were mentioned previously.

[0034] Thus, in this configuration, the gas in the vapor state intended to supply the gas-consuming device also circulates within the second heat exchanger before being compressed by the first compression device. This circulation takes place downstream of the convergence point at which the supply line joins the supply circuit, thus ensuring the circulation of the gas in the vapor state within the second heat exchanger, whether said gas in the vapor state comes from the tank or the secondary reservoir. This configuration can also be coupled with the alternative described previously, defining a three-flow heat exchange within the first heat exchanger.

[0035] According to a feature of the invention, the feed system comprises a liquid gas return line connected to the liquid outlet of the separator. The liquid fraction present in the separator is composed of gas in the liquid state which has been correctly reliquefied. This fraction can then be evacuated through the liquid outlet of the separator.

[0036] According to a feature of the invention, the liquid gas return line can extend to the tank. According to a first embodiment of the supply system, the reliquefied gas can return to where it came from, i.e., into the tank. Thus, regardless of the quantity of gas evaporating within the tank, the evaporated gas returns to it in the liquid state. In the event that the gas-consuming device is supplied entirely using the gas contained in the secondary tank, the quantity of gas contained in the tank remains constant or substantially constant over time.

[0037] According to a feature of the invention, the liquid gas return line can extend to the secondary tank. In a second embodiment, the reliquefied gas can return to the secondary tank in order to supply the latter with gas in the liquid state. The second embodiment, although using part of the cargo contained in the tank to refuel the secondary tank, has several advantages. First of all, it allows the secondary tank to be refueled with gas, which means that the size of the secondary tank does not depend on the duration of the journey of the floating structure. The second embodiment therefore allows the use of a secondary tank having a small volume, thus limiting the mechanical size of the supply system.In addition, the second embodiment makes it possible to improve the autonomy of the supply system which can then self-supply so that the gas-consuming device is supplied with fuel permanently and independently at a starting volume of gas in the liquid state within the secondary tank.

[0038] Although, for this second embodiment, a reduction in the original volume of the gas cargo contained in the tank is proportional to the quantity of gas evaporating in the tank, the objective of the supply system according to the invention is maintained, namely to use as a priority the gas contained in the secondary tank to supply the gas-consuming device, and thus limit as much as possible the loss of the volume of the gas cargo contained in the tank.

[0039] According to a feature of the invention, the supply system may comprise a circuit for refueling the secondary tank, the refueling circuit comprising an additional pumping device configured to draw gas in the liquid state from the tank, the refueling circuit extending to the secondary tank. This is a third embodiment of the supply system according to the invention. Just like the first embodiment, the gas reliquefied by the supply system then returns to the tank. However, unlike the first embodiment but just like the second embodiment, it is possible to transfer gas from the tank to the secondary tank in order to fill the latter.This third embodiment therefore also makes it possible not to depend entirely on an initial volume of gas contained in the secondary tank, the refueling circuit can always be used in an emergency if the secondary tank is empty. The additional pumping device allows the circulation of gas in the liquid state from the tank to the secondary tank if necessary.

[0040] According to a characteristic of the invention, the secondary tank is configured to be supplied with gas in the liquid state by supply means external to the supply system. Whatever the embodiment among those described previously, the secondary tank is preferably filled independently of the rest of the supply circuit, for example before the departure of the floating structure from a starting point. This has the advantage of allowing the secondary tank to be cold and therefore capable of allowing the reliquefaction of the gas resulting from the evaporation of the gas in the liquid state present in the tank upon departure from the floating structure.

[0041] If the secondary tank cannot be refilled in any other way than by external refueling means, as is the case for the first embodiment of the supply system, the volume of gas poured into the secondary tank is calculated according to the expected duration of the journey and other parameters such as, for example, the weather or the chemical composition of the gas.

[0042] If the secondary tank can be refueled during the journey via the gas contained in the tank, as for the second and third embodiments of the supply system, the secondary tank can be filled with an arbitrary volume, depending on the parameters previously mentioned, according to a maximum of its capacity, or according to any other criterion, which allows the use of a secondary tank with an internal volume independent of the characteristics of the journey of the floating structure. As mentioned previously, although there is a higher risk of consuming part of the cargo contained in the tank, this nevertheless makes it possible to limit the mechanical size of the secondary tank due to an excessively large size. The external refueling means can for example be a loading station in a port.

[0043] The invention also covers a floating structure configured to transport and / or store gas in the liquid state, comprising at least one gas-consuming apparatus and at least one supply system as described above. In the context of the invention, the floating structure is intended to deliver the aforementioned cargo to a destination point, for example a port.

[0044] The invention also covers a method for supplying at least one gas-consuming device of a floating structure, implemented by a gas supply system as described above, during which: the gas-consuming device is supplied via at least the supply line by taking the gas in the vapor state contained in the secondary tank, if there is no gas available in the secondary tank, the gas-consuming device is supplied via the supply circuit by taking the gas in the vapor state contained in the tank.

[0045] According to a characteristic of the process, the gas-consuming device is supplied via the evaporation line by taking the gas in the liquid state contained in the secondary tank if there is no gas in the vapor state available in the secondary tank.

[0046] As mentioned above, the gas in the secondary tank is the primary fuel for the gas-consuming appliance, with the gas in the tank being used only as a last resort to fuel the appliance. The secondary tank is therefore the primary source of gas for supplying the gas-consuming appliance, either through the supply line or the evaporation line.

[0047] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0048] [fig 1] represents a first embodiment of a power supply system according to the invention,

[0049] [fig 2] represents a first variant of the first embodiment of the power supply system according to the invention,

[0050] [fig 3] represents a second embodiment of the power supply system according to the invention,

[0051] [fig 4] represents a third embodiment of the power supply system according to the invention,

[0052] [fig 5] represents a second variant of the first embodiment of the power supply system according to the invention.

[0053] Figure 1 represents a gas supply system 1 for at least one gas-consuming device 2 of a floating structure according to the invention. In all the figures, a first gas-consuming device 2a and a second gas-consuming device 2b are represented but the supply system 1 is capable of supplying gas to an indefinite number of gas-consuming devices 2, the essential thing being that the supply system 1 can meet a gas supply requirement of each of them. By way of example, the first gas-consuming device 2a may be an engine ensuring the propulsion of the floating structure, while the second gas-consuming device 2b may be a generator supplying the floating structure with electricity.

[0054] The supply system 1 also comprises a membrane tank 3 containing a cargo of gas in the liquid state, for example natural gas. This cargo is transported by the floating structure and is intended to be delivered to a destination point, for example a destination port. The tank 3 has a plurality of membranes ensuring both sealing and thermal insulation in order to maintain the cargo of gas in the liquid state as much as possible. Despite the thermal insulation of the tank 3, the cargo of gas in the liquid state partially evaporates over time and gas in the vapor state forms at the level of a head of the tank 3. The presence of gas in the vapor state leads to an increase in the saturation pressure of the tank 3. The gas in the vapor state forming in the tank 3 must therefore be treated in one way or another in order to avoid overpressure of the tank 3 which risks damaging the walls and / or the membranes thereof.

[0055] The supply system 1 therefore comprises a supply circuit 4 provided with a first compression device 5 configured in particular to suck the gas in the vapor state contained in the tank 3. The supply circuit 4 connects the tank 3 to the gas-consuming devices 2 and is therefore capable of supplying the latter with the gas in the vapor state contained in the tank 3. Since the gas-consuming devices 2 have pressure requirements for the consumption of the gas supplied to them, the first compression device 5 is also responsible for raising the pressure of the gas in the vapor state to a pressure compatible with the gas-consuming devices 2. The gas in the vapor state formed in the top of the tank 3 can thus be evacuated from the tank thanks to the supply circuit 4.

[0056] The feed system 1 also comprises a reliquefaction line 6 which begins at a divergence point 7 arranged at the feed circuit 4 between the tank 3 and the first compression device 5. The reliquefaction line 6 has the objective of circulating gas in the vapor state forming within the tank 3 and intended to be reliquefied. The gas in the vapor state is sucked into the reliquefaction line 6 using a second compression device 8 arranged on the reliquefaction line 6.

[0057] The presence of two compression devices 5, 8 separate from each other makes it possible to isolate the supply circuit 4 and the reliquefaction line 6. To avoid wasting gas by sending it in a quantity greater than the need of one or more gas-consuming devices 2, it is important to know the exact quantity of gas in the vapor state compressed by the first compression device 5, which can prove complex if a compression device aims to compress both the gas intended to be consumed and the gas intended to be reliquefied. This problem is circumvented by the presence of the two compression devices 5, 8 each compressing the gas in the vapor state intended to be consumed or to be reliquefied.The circulation of the gas in the vapor state within the supply circuit 4 is controlled by a first valve 31 arranged on the supply circuit 4 between the divergence point 7 and the first compression device 5, while the circulation of the gas in the vapor state within the reliquefaction line 6 is controlled by a second valve 32 arranged on the reliquefaction line 6 between the divergence point 7 and the second compression device 8.

[0058] For safety reasons, the supply system 1 comprises a secondary line 27 providing a direct fluid connection between the reliquefaction line 6 downstream of the second compression device 8 and the gas-consuming devices 2. The secondary line 27 is useful for supplying the gas-consuming devices 2 in the event of a failure of the first compression device 5. It is thus always possible to supply the gas-consuming devices 2, the second compression device 8 and the secondary line 27 providing redundancy for the first compression device 5. It is obvious in this respect that the second compression device 8 is capable of raising the pressure of the gas in the vapor state to a pressure compatible with the needs of the gas-consuming devices 2. In this configuration, the latter are therefore supplied by the gas in the vapor state coming from the tank 3.The circulation of gas in the vapor state within the secondary line 27 is controlled by a third valve 33.

[0059] In order to reliquefy the gas in the vapor state, the supply system 1 comprises a first heat exchanger 9 and a cooling circuit 10 within which circulates gas in the liquid state having a lower temperature than the gas in the vapor state circulating within the reliquefaction line 6. A heat exchange takes place within the first heat exchanger 9 between the gas in the liquid state circulating in the cooling circuit 10 and the gas in the vapor state circulating within the reliquefaction line 6 in order to reliquefy the latter. It is thus understood that the supply system 1 has means for supplying the gas-consuming appliances 2 with the gas in the vapor state present in the tank 3 as well as means for reliquefying said gas in the vapor state.Consumption of the gas present in tank 3 can however be problematic because part of the cargo intended for delivery is consumed, creating a lack of gas volume once it arrives at its destination.

[0060] To overcome this, the supply system 1 according to the invention comprises a secondary tank 11 also containing a volume of gas in the liquid state not forming part of the cargo intended to be delivered. It is primarily from the gas contained in this secondary tank 11 that the gas-consuming devices 2 are supplied, in order to preserve the gas cargo contained in the tank 3, the supply system 1 being capable of implementing a method for supplying one or more gas-consuming devices 2 along these lines.

[0061] In addition, it is the gas contained in the secondary tank 11 which circulates within the cooling circuit 10 in order to reliquefy the gas in the vapor state circulating in the reliquefaction line 6. This makes it possible not to disturb the temperature of the gas in the liquid state contained in the tank 3 by not using it as a cooling means.

[0062] Unlike tank 3, secondary tank 11 has self-supporting walls, which is a different structure from membrane tank 3. The self-supporting walls provide thermal insulation but also have greater overpressure resistance than membrane tank 3, thus allowing a higher accumulation of gas in the vapor state.

[0063] The supply system 1 according to the invention therefore ensures that as much as possible it is avoided to supply the gas-consuming appliances 2 with the gas in the vapor state forming in the tank 3 and to favor said supply with gas in the vapor state forming in the secondary tank 11. The supply system 1 therefore comprises a supply line 12 which extends from the secondary tank 11 to the supply circuit 4. The gas-consuming appliances 2 can thus be supplied with the gas in the vapor state coming from the secondary tank and circulating in the supply line 12.

[0064] Advantageously, the supply line 12 is connected to the supply circuit at a convergence point 26 arranged on the supply circuit 4, said convergence point 26 being positioned on the supply circuit 4 between the divergence point 7 and the first compression device 5. This connection allows the compression of the gas coming from the supply line 12 by the first compression device 5, and thus avoids the need to install an additional compression device dedicated to the compression of the gas in the vapor state circulating in the supply line 12. In this configuration, the first compression device 5 is therefore able to suck the gas in the vapor state contained in the secondary tank 11 and raise it to a pressure compatible for one or more gas-consuming appliances 2. The circulation of the gas within the supply line 12 to the first compression device 5 is controlled by a fourth valve 34.The gas contained in the secondary tank 11 is therefore used permanently to supply the gas-consuming devices 2, as long as a power source for the gas-consuming devices 2 is available within the secondary tank 11. Advantageously, throughout the journey made by the floating structure, the gas-consuming devices 2 are permanently supplied by the gas from the secondary tank 11 while all of the gas in the vapor state forming in the tank 3 is intended to circulate in the reliquefaction line 6 to be reliquefied and not consumed.

[0065] As mentioned previously, the gas in the liquid state contained in the secondary tank 11 is also used to effect the cooling, advantageously the total reliquefaction, of the gas in the vapor state coming from the tank 3. The cooling circuit 10 thus comprises a pumping device 13 making it possible to take the gas in the liquid state from the secondary tank 11. The gas in the liquid state circulates in the cooling circuit 10 and passes through the first heat exchanger 9 in order to cool the gas in the vapor state circulating in the reliquefaction line 6 and also passing through the first heat exchanger 9. In Figure 1, the pumping device 13 is shown outside the secondary tank 11, but as will be seen later, the pumping device 13 can also be placed within an internal volume of the secondary tank 11.

[0066] The gas in the liquid state circulating in the cooling circuit 10 undergoes a rise in temperature following the heat exchange occurring in the first heat exchanger 9 and then returns to the secondary tank 11. This return causes an increase in the temperature of the gas in the liquid state of the secondary tank 11, thus promoting the production of gas in the vapor state used to supply the gas-consuming devices 2.

[0067] In addition, the supply system 1 comprises an evaporation line 14, connected to the cooling circuit 10 downstream of the first heat exchanger 9 relative to the direction of circulation of the gas in the liquid state in the cooling circuit 10. The evaporation line 14 makes it possible to circulate the gas from the cooling circuit 10 so as to use it to supply the gas-consuming appliances 2. This evaporation line 14 can be used in the event of the absence or too low presence of gas in the vapor state in the secondary tank 11 and is preferably used as a priority to supply the gas-consuming appliances 2 compared to a supply via the gas in the vapor state contained in the tank 3.

[0068] The gas-consuming devices 2 only tolerate gas in the vapor state for supply. The gas circulating in the cooling circuit 10 then in the evaporation line 14 being in the liquid state, the supply system 1 comprises an evaporation device 15 ensuring the evaporation of the gas in the liquid state circulating within the evaporation line 14. The evaporation device 15 can for example carry out evaporation via a heat exchange with a third fluid, such as sea water.

[0069] The gas circulating in the evaporation line 14 is thus evaporated and can then be consumed by the gas-consuming devices 2. The evaporation line 14 can then first join the supply circuit 4 before being sent to one or more gas-consuming devices 2. Advantageously, it is not necessary for the evaporated gas to be compressed by the first compression device 5 before being sent to the gas-consuming devices 2. As a reminder, the gas circulating in the evaporation line 14 initially comes from the cooling circuit 10, and the pumping device 13 is capable of raising the pressure of the gas in the liquid state to a pressure compatible with the gas-consuming devices 2. The circulation of the gas within the evaporation line 14 is controlled by a fifth valve 35.

[0070] It is thus understood that the supply system 1 according to the invention, particularly the secondary tank 11 and the elements attached thereto, have the capacity on the one hand to reliquefy the gas in the vapor state forming in the tank 3, and on the other hand to supply the gas-consuming devices 2 in place of the gas in the vapor state forming in the tank 3 in order to avoid a reduction in the volume of the cargo of gas contained in the tank 3.

[0071] In order to promote reliquefaction within the first heat exchanger 9, the supply system 1 comprises a second heat exchanger 21 within which at least two streams of gas in the vapor state circulate. The second heat exchanger 21 ensures pre-cooling of the gas in the vapor state circulating in the reliquefaction line 6, which facilitates its subsequent reliquefaction.

[0072] In Figure 1, within the second heat exchanger 21, a heat exchange is carried out between the gas in the vapor state circulating in the reliquefaction line 6 between the divergence point 7 and the second compression device 8 and the gas in the vapor state circulating in the reliquefaction circuit 6 between the second compression device 8 and the first heat exchanger 9.

[0073] By means of the second heat exchanger 21, the gas in the vapor state circulating in the reliquefaction circuit 6 between the second compression device 8 and the first heat exchanger 9 is precooled before passing through the first heat exchanger 9. The gas in the vapor state circulating in the reliquefaction line 6 between the point of divergence 7 and the second compression device 8 offers a source of temperature reduction because it comes directly from the tank 3 and is not yet compressed by the second compression device 8. At the outlet of the first heat exchanger 9, the gas circulating in the reliquefaction line 6 is at least partially reliquefied, ideally entirely reliquefied. However, it is conceivable that the gas circulating in the reliquefaction line 6 at the outlet of the first heat exchanger 9 is in a two-phase state, that is to say partly in the liquid state and partly in the vapor state.In which case the gas in the two-phase state continues its circulation within the reliquefaction line 6 until it reaches a separator 16, which allows the separation of a liquid fraction and a vapor fraction of the gas in the two-phase state.

[0074] The separator 16 comprises an inlet 17 where the reliquefaction line 6 opens and thus allows the gas in the two-phase state to enter the separator 16. The separator 16 also comprises a vapor outlet 18 through which the vapor fraction of the gas in the two-phase state exits and a liquid outlet 19 through which the liquid fraction of the gas in the two-phase state exits.

[0075] The fraction of gas in the vapor state constitutes the fraction of gas that has not reliquefied during the heat exchange occurring within the first heat exchanger 9. The supply system 1 therefore comprises a vapor gas return line 20 extending between the vapor outlet 18 of the separator 16 and the reliquefaction line 6, between the divergence point 7 and the second heat exchanger 21. The vapor gas return line 20 ensures recirculation of the gas that has not reliquefied to the reliquefaction line 6, in order to carry out a new heat exchange for the purpose of reliquefaction.

[0076] In Figure 1, the vapor gas return line 20 is fluidically connected to the divergence point 7, which here acts as a junction point. This fluidic connection makes it possible to recirculate the fraction of gas in the vapor state in the reliquefaction line 6. As illustrated in Figure 1, the vapor gas return line can also be fluidically connected to the supply line 12 in the event that the fraction of gas in the vapor state coming from the separator 16 is used to supply the gas-consuming devices 2. The circulation of the gas in the vapor state circulating in the vapor gas return line 20 and intended to recirculate in the reliquefaction line 6 is controlled by a sixth valve 36. The circulation of the gas in the vapor state circulating in the vapor gas return line 20 and intended to supply the gas-consuming devices 2 is controlled by a seventh valve 37.

[0077] The fraction of gas in the liquid state contained in the separator 16 constitutes the fraction of gas having reliquefied during the heat exchange occurring within the first heat exchanger 9. According to the first embodiment of the supply system 1, the reliquefied gas leaves the separator 16 via the liquid outlet 19 and returns to the tank 3. The supply system 1 therefore comprises a liquid gas return line 22 connected to the liquid outlet 19 of the separator 16 and extending to the tank 3.

[0078] Thus, according to this first embodiment, the gas evaporating in the tank 3 is entirely reliquefied and returns entirely to the tank 3, thus maintaining the volume of the cargo constant over time, provided that the gas contained in the secondary tank 11 is sufficient in itself to supply the gas-consuming devices 2 over time.

[0079] According to this first embodiment, the tank 3 and the secondary tank 11 are independent of each other. In other words, there is no possibility of circulating gas from the tank 3 to the secondary tank 11 or vice versa. The secondary tank 11 can therefore only be filled by refueling means 23 external to the supply system 1 or even to the floating structure.

[0080] The refueling means 23 may, for example, be those which are also responsible for filling the tank 3. The latter and the secondary tank 11 may, for example, be filled at the same time, when loading the gas in the liquid state into the floating structure. The volume of gas in the liquid state within the secondary tank may be chosen according to various parameters such as the travel time to the destination point, the weather forecast or the chemical composition of the gas transported. Alternatively, the secondary tank 11 may be filled to the maximum of its capacity without any other distinctions. Figure 2 shows a first variant of the first embodiment of the supply system 1 according to the invention. This first variant has characteristics distinct from what has been described in Figure 1 with regard to the gas vapor return line 20 as well as the second heat exchanger 21.

[0081] Concerning this first variant, the vapor gas return line 20 also extends to the reliquefaction line 6, but this time between the second heat exchanger 21 and the second compression device 8. In addition, the vapor gas return line 20 passes through the second heat exchanger 21 which here then operates a heat exchange between three gas flows.

[0082] By means of the second heat exchanger 21, the gas in the vapor state circulating in the reliquefaction circuit 6 between the second compression device 8 and the first heat exchanger 9 is precooled before passing through the first heat exchanger 9. As previously described, the gas in the vapor state circulating in the reliquefaction line 6 between the divergence point 7 and the second compression device 8 offers a source of temperature reduction because it comes directly from the tank 3 and is not yet compressed by the second compression device 8. Furthermore, concerning this first variant, the gas in the vapor state circulating in the vapor gas return line 20 also guarantees a source of temperature reduction. The gas in the vapor state circulating in the vapor gas return line 20 then joins the reliquefaction line 6 at the outlet of the second heat exchanger 21.

[0083] 11 It should be noted that the supply system 1 as described in FIG. 2 comprises an evacuation line 28 connected to the vapor gas return line 20, downstream of the second heat exchanger 21. The evacuation line 28 extends to the supply circuit 4, upstream of the first compression device 5.

[0084] The discharge line 28 allows the gas in the vapor state to be discharged from the vapor gas return line 20 and sent to the gas consuming devices 2. This discharge line 28 is used in the event of excess nitrogen within the gas in the vapor state circulating in the vapor gas return line 20. Indeed, the gas cargo can potentially contain a small quantity of nitrogen, which reliquefies at a lower temperature than the hydrocarbons which are the major components of the gas cargo.

[0085] The nitrogen contained in the gas cargo therefore remains in the vapor state despite one or more passages within the first heat exchanger 9 and therefore circulates continuously in the reliquefaction line 6 and in the vapor gas return line 20. Thus, over time and with the quantity of gas in the vapor state formed in the tank 3 then circulating in the reliquefaction line 6, the nitrogen concentration gradually increases within the gas circulating in the reliquefaction line 6 and in the vapor gas return line 20, which is detrimental to the reliquefaction performance of the supply system 1.When the nitrogen concentration becomes too high, for example after a determined travel time, the gas in the vapor state circulating in the vapor gas return line 20 subsequently circulates within the discharge line 28 instead of recirculating within the reliquefaction line 6, and is then raised in pressure by the first compression device 5 before being sent to the gas-consuming devices 2.

[0086] The rest of the structural and functional elements of the first variant of the first embodiment being identical to the first embodiment described in figure 1, reference will be made to the description of figure 1 for the elements common to the two embodiments.

[0087] Figure 3 is a representation of a second embodiment of the power supply system 1 according to the invention.

[0088] This second embodiment differs from the first variant of the first embodiment in that the liquid gas return line 22 does not extend from the liquid outlet 19 of the separator 16 to the tank 3, but from the liquid outlet 19 of the separator 16 to the secondary tank 11. In other words, the gas forming in the vapor state in the tank 3 and circulating in the reliquefaction line 6 is sent to the secondary tank 11 once reliquefied.

[0089] The secondary tank 11 is therefore supplied by the gas in the vapor state forming in the tank 3 and intended to be reliquefied. Such a configuration therefore does not limit the operation of the secondary tank 11 to the volume of starting gas that it contains. This results in a reduction in the volume of the cargo of the tank 3 but nevertheless limits the waste thereof compared to a direct supply of the gas in the vapor state contained in the tank 3 to the gas-consuming devices 2. In addition, since a supply of the secondary tank 11 via the gas contained in the tank 3 is possible, the secondary tank 11 is not entirely independent of its volume of starting gas. This makes it possible to limit such a volume and therefore also to limit the size of the secondary tank 11, which makes it possible to reduce the costs as well as the spatial footprint of the supply system 1.The main means of refueling the secondary tank 11, however, remains filling via the refueling means 23 described previously.

[0090] The second embodiment differs from the first embodiment also in that the pumping device 13 ensuring the circulation of the gas in the liquid state in the cooling circuit 10 is positioned within the internal volume of the secondary tank 11. Such a positioning is advantageous in order to limit the spatial size of the supply system 1 compared to a positioning of the pumping device 13 outside the secondary tank 11.

[0091] The positioning of the pumping device 13 is however completely independent of the embodiment of the supply system 1, and a positioning of the pumping device 13 within or outside the secondary tank 11 is possible regardless of the embodiment implemented.

[0092] The remaining structural and functional elements of the second embodiment being identical to the first embodiment or to the first variant of the first embodiment, reference will be made to the description of figures 1 and 2 for the elements common to both embodiments.

[0093] Figure 4 is a representation of a third embodiment of the supply system 1 according to the invention. This third embodiment is substantially identical to the first variant of the first embodiment, in particular at the level of the liquid gas return line 22 which extends from the liquid outlet 19 of the separator 16 to the tank 3, unlike the second embodiment. However, the third embodiment of the supply system 1 further comprises a refueling circuit 24 extending between the tank 3 and the secondary tank 11. The refueling circuit 24 comprises an additional pumping device 25 preferably submerged at the bottom of the tank 3 and configured to take gas in the liquid state from the tank 3. The gas in the liquid state then circulates within the refueling circuit 24 to the secondary tank 11.

[0094] The third embodiment of the supply system 1, just like the second embodiment, therefore makes it possible to refuel the secondary tank 11 with gas during the journey and not only using the refueling means 23. The third embodiment therefore also makes it possible to limit the size of the secondary tank 11, the latter being able to be filled during the journey via the tank 3 and the refueling circuit 24.

[0095] Refueling the secondary tank 11 with liquid gas from the vessel 3 may also be a means of cooling the secondary tank 11 and providing liquid gas at a lower temperature to improve the cooling capacity within the first heat exchanger 9 and thus enable more efficient reliquefaction. The use of part of the cargo from the vessel 3 may be compensated for example by initially filling the vessel with a volume of gas greater than the intended volume of the cargo.

[0096] The rest of the structural and functional elements of the third embodiment being identical to the first embodiment or its first variant, reference will be made to the description of figures 1 and 2 for the elements common to the two embodiments.

[0097] Figure 5 shows a second variant of the first embodiment of the power supply system 1. This second variant includes structural and functional differences which are not exclusively applicable to the first embodiment. Thus, this second variant can also be applied to the second embodiment as well as to the third embodiment.

[0098] This second variant is thus distinguished from the first variant in that the supply line 12 passes through the first heat exchanger 9 before joining the supply circuit T1 4, while the latter passes through the second heat exchanger 21 before extending to the first compression device 5. Thus, the first heat exchanger 9 and the second heat exchanger 21 each have an additional flow of gas passing through them.

[0099] Such an arrangement makes it possible to exploit the cooling capacities of the gas in the vapor state intended to supply the gas-consuming devices 2. Indeed, the gas in the vapor state coming from the secondary tank 11, although having previously evaporated, has a sufficiently low temperature to participate in the heat exchange taking place within the first heat exchanger 9. The reliquefaction of the gas circulating within the reliquefaction line 6 is then improved. At the outlet of the first heat exchanger 9, the gas circulating in the supply line 12 joins the supply circuit 4.

[0100] Subsequently, the gas in the vapor state coming from the supply line 12 passes through the second heat exchanger 21 before being compressed by the first compression device 5. Such a configuration is also valid for the gas in the vapor state coming from the tank 3 if the latter is used to supply the gas-consuming appliances 2 because the gas in the vapor state circulating in the supply circuit 4 passes through the second heat exchanger 21 between the convergence point 26 and the first compression device 5.

[0101] The circulation within the second heat exchanger 21 of the gas in the vapor state circulating in the supply circuit 4 and intended to be compressed by the first compression device 5 subsequently makes it possible to improve the pre-cooling of the gas in the vapor state circulating in the reliquefaction line 6 and passing through this same second heat exchanger 21. Such pre-cooling proves effective even in the event that the gas in the vapor state circulating in the supply circuit 4 comes from the supply line 12 having undergone a rise in temperature due to having previously passed through the first heat exchanger 9. Such a configuration is thus optimal for the reliquefaction of the gas in the vapor state circulating in the reliquefaction line 6.It should be noted that, in Figure 5, the two heat exchangers 9, 21 are each crossed by an additional gas flow, but it is entirely possible to implement an additional flow on only one of these heat exchangers 9, 21. The rest of the structural and functional elements of this variant being identical to the first embodiment or to its first variant, reference will be made to the description of Figures 1 and 2 for the elements common to the variants of the supply system 1 disclosed in Figures 1, 2 and 4.

[0102] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0103] The invention, as just described, achieves the aim it set itself, and makes it possible to propose a supply system for a floating structure making it possible to limit the consumption of gas contained in a tank by a gas-consuming device of said floating structure. Variants not described here could be implemented without departing from the context of the invention, provided that, in accordance with the invention, they comprise a supply system in accordance with the invention.

Claims

CLAIMS 1- Gas supply system (1) for at least one gas-consuming device (2, 2a, 2b) of a floating structure, the supply system (1) comprising: at least one membrane tank (3) configured to contain the gas, at least one gas supply circuit (4) for the gas-consuming device (2, 2a, 2b), comprising at least one first compression device (5) configured to compress gas taken in the vapor state from the tank (3) to a pressure compatible with the needs of the gas-consuming device (2, 2a, 2b), at least one reliquefaction line (6) for the gas in the vapor state, the reliquefaction line (6) being connected to the supply circuit (4) at a divergence point (7) arranged between the tank (3) and the first compression device (5), the reliquefaction line (6) comprising a second compression device (8),at least one cooling circuit (10) comprising at least one pumping device (13) configured to draw gas in the liquid state, the supply system (1) comprising a first heat exchanger (9) configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line (6) downstream of the second compression device (8) and the gas in the liquid state circulating in the cooling circuit (10), characterized in that the supply system (1) comprises a secondary tank (11) with self-supporting walls configured to contain gas in the liquid state, said supply system (1) comprising a supply line (12) configured to draw gas in the vapor state from the secondary tank (11), the supply line (12) being connected to the supply circuit (4),the pumping device (13) of the cooling circuit (10) being configured to take the gas in the liquid state contained in the secondary tank (11)., 2- Power supply system (1) according to claim 1, in which the cooling circuit (10) extends to the secondary tank (11). 3- Power supply system (1) according to claim 1 or 2, comprising an evaporation line (14) connected to the cooling circuit (10) downstream of the first heat exchanger (9) and extending to the supply circuit (4) downstream of the first compression device (5), the supply system (1) comprising an evaporation device (15) configured to evaporate the gas circulating in the evaporation line (14). 4- Supply system (1) according to any one of claims 1 to 3, wherein the first heat exchanger (9) is configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line (6) downstream of the second compression device (8), the gas in the liquid state circulating in the cooling circuit (10), and the gas in the vapor state circulating in the supply line (12). 5- Supply system (1) according to any one of claims 1 to 4, comprising a second heat exchanger (21) configured to carry out a heat exchange at least between the gas in the vapor state circulating in the reliquefaction line (6) between the divergence point (7) and the second compression device (8) and the gas in the vapor state circulating in the reliquefaction line (6) between the second compression device (8) and the first heat exchanger (9). 6- Feed system (1) according to any one of claims 1 to 5, comprising a separator (16) provided with an inlet (17), a liquid outlet (19) and a vapor outlet (18), the reliquefaction line (6) extending to the inlet (17) of the separator (16). 7- Feed system (1) according to claim 6, in combination with claim 5, comprising a vapor gas return line (20) connected to the vapor outlet (18) of the separator (16) and extending at least as far as the reliquefaction line (6) between the divergence point (7) and the second heat exchanger (21). 8- Feed system (1) according to claim 6, in combination with claim 5, comprising a vapor gas return line (20) connected to the vapor outlet (18) of the separator (16) and extending to the reliquefaction line (6) between the second heat exchanger (21) and the second compression device (8), the second heat exchanger (21) being configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line (6) between the point of divergence (7) and the second compression device (8), the gas in the vapor state circulating in the reliquefaction line (6) between the second compression device (8) and the first heat exchanger (9), and the gas in the vapor state circulating in the vapor gas return line (20). 9- Supply system (1) according to claim 8, wherein the second heat exchanger (21) is configured to carry out a heat exchange between the gas in the vapor state circulating in the reliquefaction line (6) between the point of divergence (7) and the second compression device (8), the gas in the vapor state circulating in the reliquefaction line (6) between the second compression device (8) and the first heat exchanger (9), the gas in the vapor state circulating in the vapor gas return line (20), and the gas in the vapor state circulating in the supply circuit (4) between a point of convergence (26) at which the supply line (12) is connected to the supply circuit (4), and the first compression device (5). 10- Feed system (1) according to any one of claims 6 to 9, comprising a liquid gas return line (22) connected to the liquid outlet (19) of the separator (16). 11- Feed system (1) according to claim 10, wherein the liquid gas return line (22) extends to the tank (3). 12- Supply system (1) according to claim 10, wherein the liquid gas return line (22) extends to the secondary tank (11). 13- Supply system (1) according to claim 11, comprising a refueling circuit (24) for the secondary tank (11), the refueling circuit (24) comprising an additional pumping device (25) configured to take gas in the liquid state from the tank (3), the refueling circuit (24) extending to the secondary tank (11). 14- Supply system (1) according to any one of claims 1 to 13, in which the secondary tank (11) is configured to be supplied with gas in the liquid state by supply means (23) external to the supply system (1). 15- Floating structure configured to transport and / or store gas in the liquid state, comprising at least one gas-consuming device (2, 2a, 2b) and at least one supply system (1) according to any one of claims 1 to 14. 16- Method for supplying at least one gas-consuming device (2, 2a, 2b) of a floating structure, implemented by a gas supply system (1) according to any one of claims 1 to 14, during which: the gas-consuming device (2, 2a, 2b) is supplied via at least the supply line (12) by taking the gas in the vapor state contained in the secondary tank (11), if there is no gas available in the secondary tank (11), the gas-consuming device (2, 2a, 2b) is supplied via the supply circuit (4) by taking the gas in the vapor state contained in the tank (3).17- Feeding method according to claim 16, implemented by a feed system (1) according to any one of claims 3 to 14 in combination with claim 3, during which the gas-consuming device (2, 2a, 2b) is fed via the evaporation line (14) by taking the gas in the liquid state contained in the secondary tank (11) if there is no gas in the vapor state available in the secondary tank (11).

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