Gas supply system for at least one gas-consuming appliance on a floating structure

Abstract

Gas supply system for at least one gas-consuming appliance of a floating structure. The present invention relates to a gas supply system (1) for a gas-consuming appliance (3, 3a, 3b), comprising: a first gas supply circuit (4) for the gas-consuming appliance (3, 3a, 3b), a gas return line (6) connected to the first supply circuit (4), the supply system (1) comprising at least one heat exchanger (7), a second gas supply circuit (8) for the gas-consuming appliance (3, 3a, 3b), comprising an evaporation device (10) configured to vaporize the gas into a liquid state, characterized in that the return line (6) and the second supply circuit (8) share a common portion (11), the common portion (11) being disposed downstream of the heat exchanger (7) and upstream of the evaporation device (10). (Figure 1)

Description

Title of the invention: Gas supply system for at least one gas-consuming appliance of a floating structure

[0001] The present invention relates to the field of floating structures for the storage and / or transport of gas in liquid state and more particularly concerns a gas supply system for at least one gas-consuming device included within such floating structures.

[0002] During a journey undertaken by a ship comprising at least one tank of gas in liquid form intended for consumption and / or delivery to a point of destination, said ship may be capable of using at least a portion of said gas in liquid form to supply at least one of its gas-consuming appliances, via a gas supply system.

[0003] Generally, it is known that preference should be given to using the gas that has evaporated within the tank to supply the gas-consuming appliance. Such evaporation can occur following an overall increase in the tank's temperature over time, and the generated vapor gas must be vented to prevent overpressure in the tank. The gas supply to the gas-consuming appliance is provided using the supply system described above. Any excess vapor gas can be returned to the tank via a return line, after being cooled beforehand.

[0004] When the gas in vapor form is present in too small a quantity to meet the supply requirements of the gas-consuming device, the supply system can also address this problem by taking gas in liquid form from the tank and evaporating it before sending it to the gas-consuming device.

[0005] All these functionalities of such a supply system necessarily generate a significant quantity of materials, such as pipes, which inevitably results in considerable spatial and mechanical bulk, especially if the floating structure is equipped with multiple tanks. Such bulk can prove problematic if one wishes to modify a supply system by adding functionalities, and therefore necessarily adding more materials. The lack of space can thus prevent any potential improvement of certain supply systems.

[0006] The present invention makes it possible to circumvent this problem of spatial and mechanical bulk and, as such, proposes a gas supply system for at least one gas-consuming appliance of a floating structure comprising at least one tank configured to contain the gas, the supply system comprising: - at least one first gas supply circuit for the gas-consuming appliance, comprising at least one compression device configured to compress gas taken from the tank in vapor form to a pressure compatible with the requirements of the gas-consuming appliance; - a gas return line connected to the first supply circuit downstream of the compression device and extending to the tank; the supply system comprising at least one heat exchanger configured to perform heat exchange between the gas circulating in the first supply circuit and the gas circulating in the return line. - at least one second gas supply circuit for the gas-consuming appliance, comprising at least one pump configured to pump the gas drawn in liquid form from the tank and at least one evaporation device configured to vaporize the gas in liquid form,

[0007] characterized in that the return line and the second power supply circuit share a common portion.

[0008] Thanks to the supply system according to the invention, it is possible to partially combine the return line and the second supply circuit in order to limit the number of pipes required for the design of said supply system. This can prove useful when adding an element to a supply system already partially installed within the floating structure. For example, adding the return line and the heat exchanger to a floating structure already comprising the first and second supply circuits is facilitated by the fact that part of the pipe used for the return line is already part of the second supply circuit. This avoids adding pipes that would further clutter the space used by the supply system and simplifies the circuits.Another advantage is reducing the number of line penetrations through the tank, thus limiting the risk of tank leaks.

[0009] The first supply circuit allows the vaporized gas formed in the tank to be extracted and used as fuel for the gas-consuming appliance. Although the tank has thermal insulation properties, vaporized gas naturally forms over time and must be treated in some way to limit the pressure increase in the tank. The first supply circuit therefore allows it to be used as fuel for the gas-consuming appliance. The compression device, in addition to drawing the vaporized gas out of the tank, increases its pressure to a level compatible with the gas-consuming appliance, for example, between 6 and 18 bar.

[0010] The gas-consuming device may, for example, be an engine providing propulsion for the floating structure or an electric generator supplying power to the structure floating in electricity. It is also possible that the supply system is capable of supplying a plurality of gas-consuming appliances, in which case the first supply circuit is adapted accordingly in order to be able to supply each of them with gas in the vapor state.

[0011] The return line is connected to the first supply circuit downstream of the compression device and allows the circulation of excess gas vapor relative to the supply requirements of the gas-consuming appliance. Instead of wasting this excess gas vapor, it flows through the return line to return to the tank. The heat exchanger cools the vapor during its return by exchanging heat with the gas vapor exiting the tank and circulating in the first supply circuit. The excess gas vapor is thus retained by returning to the tank instead of being burned or released into the atmosphere.

[0012] The second supply circuit is used in case of a shortage of gas in vapor form in the tank to meet the supply requirements of the gas-consuming appliance. The pump draws the gas in liquid form and raises it to a pressure compatible with the gas-consuming appliance. The evaporation device then evaporates the gas into a liquid state so that it can subsequently be used by the gas-consuming appliance. The evaporation of the gas into a liquid state can be achieved, for example, by heat exchange with a third-party fluid, such as seawater.

[0013] The common section is part of both the return line and the second supply circuit, in order to avoid increasing the number of pipes in the supply system. Partially combining the return line and the second supply circuit is advantageous because the return line is used when there is an excess of vapor gas relative to the needs of the gas-consuming appliance, while the second supply circuit is used when the vapor gas is present in insufficient quantity or absent and therefore cannot meet the needs of the gas-consuming appliance on its own. Thus, the return line and the second supply circuit are never used simultaneously. Implementing a common section for the return line and the second supply circuit is therefore entirely feasible without compromising the overall operation of the supply system.

[0014] According to an optional feature of the invention, the common portion is connected between the heat exchanger and the evaporation device. For example, the common portion is fluidically connected to the circuit downstream of the heat exchanger and upstream of the evaporation device, viewed along the same direction of gas flow.

[0015] According to one feature of the invention, the common portion is configured to allow gas to circulate in a first direction of flow or in a second direction of flow opposite to the first direction of flow. Indeed, when the gas flows in the return line, it flows towards the tank to return to it, whereas when the gas flows in the second supply circuit, it flows from the tank towards the gas-consuming appliance, in a direction of flow opposite to that of the gas flowing in the return line.

[0016] According to one feature of the invention, the common portion comprises a first end and a second end from which the return line and the second supply circuit separate, the common portion being configured to circulate the gas flowing in the return line in the first direction of circulation from the first end to the second end, and to circulate the gas flowing in the second supply circuit in the second direction of circulation from the second end to the first end.

[0017] The first and second ends define the common section and each constitute a junction point between the return line and the second supply circuit. As described previously, the gas does not flow in the same direction depending on whether it flows in the return line or in the second supply circuit. The first end corresponds to the end of the common section furthest from the tank, while the second end corresponds to the end of the common section closest to the tank. Therefore, the gas does not flow from the same end to the same other end depending on whether it flows in the return line or in the second supply circuit.

[0018] According to one feature of the invention, the return line includes a branch configured to extend from the second end of the common section to the bottom of the tank. The branch corresponds to the portion of the return line extending between the common section and the tank. This branch is independent of the second supply circuit so as not to damage the pump submerged in the tank and forming part of the second supply circuit.

[0019] The branch can advantageously be positioned entirely at the bottom of the tank or at least immersed within the tank. Functionally, such a variant does not differ from a branch located within the piping of the supply system. However, placing the branch within the tank avoids the need for additional piping within the supply system, thereby helping to limit the overall footprint of the supply system.

[0020] According to one feature of the invention, the branching comprises an ejector configured to be arranged at the bottom of the tank. This is a first method of Implementation of the feed system according to the invention. In this first embodiment, the ejector constitutes the last element of the return line before the gas circulating in it is returned to the tank. Indeed, although the heat exchanger cools the gas in its vapor state, such cooling is not sufficient to liquefy the gas circulating in the return line. The ejector overcomes this by ensuring a mixture between the vapor gas circulating in the return line and the liquid gas at the bottom of the tank, so that the vapor gas is released at the bottom of the tank in its liquid state. The ejector is advantageously located as deep as possible in the tank because the temperature of the liquid gas is lowest at the bottom of the tank.

[0021] According to one feature of the invention, the heat exchanger is a first heat exchanger, the feed system comprising a cooling circuit and a second heat exchanger, the cooling circuit comprising a pumping device configured to pump the gas drawn in liquid form from the tank, the second heat exchanger being configured to perform a heat exchange between the gas in vapor form circulating in the return line and the gas in liquid form circulating in the cooling circuit. This is a second embodiment of the feed system according to the invention.

[0022] In this second embodiment, the gas in vapor form is liquefied using two heat exchangers before returning to the tank. This embodiment ensures that the gas flowing in the return line returns directly to the tank in a liquid state.

[0023] The cooling circuit allows the gas to be pumped in liquid form into the tank, and allows the gas to be liquefied in vapor form by circulating in the second heat exchanger.

[0024] According to one feature of the invention, the first heat exchanger is configured to cool the gas in the vapor state circulating in the return line, while the second heat exchanger is configured to liquefy the gas in the vapor state circulating in the return line. In other words, the gas in the vapor state first circulates within the first heat exchanger to be pre-cooled by heat exchange with the gas in the vapor state circulating in the first supply circuit, and then circulates within the second heat exchanger to be condensed by heat exchange with the gas in the liquid state circulating in the cooling circuit. From the point of view of the gas circulation in the return line, the second heat exchanger is therefore downstream of the first heat exchanger.

[0025] According to one feature of the invention, the cooling circuit and the return line join downstream of the second heat exchanger and upstream from the first end of the common section. In other words, the liquefied gas circulating in the return line and the liquid gas circulating in the cooling circuit meet at the outlet of the second heat exchanger before traveling through the common section and then returning to the tank. This configuration contributes to limiting the number of pipes within the supply system according to the invention.

[0026] According to one feature of the invention, the supply system comprises at least one control element configured to control the gas flow within the return line and / or the second supply circuit and / or the branch. The control element manages the gas flow within the supply system, based on the activity of the supply system and therefore on the direction of gas flow within the common section. Advantageously, the system comprises a plurality of control elements to improve the management of gas flow within the supply system.

[0027] The control device may, for example, be a valve or any other element configured to allow or prevent the flow of gas within a particular section. As another non-exhaustive example, the control device may be a check valve or any other element that allows gas to flow in one direction but prevents gas to flow in the opposite direction.

[0028] The invention also covers a floating structure for the transport and / or storage of gas in liquid state, comprising at least one tank configured to contain the gas, at least one gas-consuming device and at least one supply system as described above.

[0029] The invention also covers a method of supplying at least one gas-consuming appliance of a floating structure comprising at least one tank configured to contain the gas, implemented by a supply system as described above, during which: - when the quantity of gas in vapor form contained in the tank exceeds the supply requirement of the gas-consuming appliance, the gas-consuming appliance is supplied via the first supply circuit from the gas in vapor form contained in the tank, with an excess of gas in vapor form circulating in the return line, the excess gas circulating in the common section in a first direction of flow, - when the quantity of gas in vapor form contained in the tank is less than the supply requirement of the gas-consuming appliance, the gas-consuming appliance is supplied at least via the second supply circuit from the gas in liquid form contained in the tank, the gas to the liquid state circulating in the common section in a second direction of circulation opposite to the first direction of circulation.

[0030] The flow of the gas supply process, and therefore the direction of gas flow within the common section, depends on the quantity of gas in vapor form present in the tank and the supply requirements of the gas-consuming appliance. It is possible that the supply system may be configured to supply gas to several gas-consuming appliances, in which case the supply requirements of all the gas-consuming appliances must be taken into account.

[0031] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given with reference to the accompanying schematic drawings on the other hand, in which:

[0032] [Fig. 1] is a schematic representation of a first embodiment of a power supply system according to the invention arranged within a floating structure equipped with at least one gas-consuming device,

[0033] [Fig.2] is a diagram of gas circulation within the first embodiment of the supply system when gas in vapor state is available in excessive quantity relative to the supply requirement of the gas-consuming device,

[0034] [Fig.3] is a diagram of gas circulation within the first embodiment of the supply system when gas in vapor state is available in too small a quantity relative to the supply requirement of the gas-consuming device,

[0035] [Fig.4] is a schematic representation of a second embodiment of the power supply system according to the invention,

[0036] [Fig.5] is a gas circulation diagram within the second embodiment of the supply system when gas in vapor state is available in excessive quantity relative to the supply requirement of the gas-consuming device,

[0037] [Fig.6] is a gas circulation diagram within the second embodiment of the supply system when gas in vapor state is available in too small a quantity relative to the supply requirement of the gas-consuming device,

[0038] [Fig.7] is a schematic representation of the first embodiment of the supply system according to the invention, adapted to a floating structure comprising two tanks configured to contain the gas.

[0039] Figure 1 is a schematic representation of a first embodiment of a gas supply system 1 according to the invention. Such a supply system 1 can, for example, be integrated into a floating structure for the transport and / or storage of gas in the liquid state, said gas being, for example, natural gas, also known as LNG. Such a floating structure comprises at least one tank 2 for the transport and / or storage of the gas in the liquid state and at least one device gas consumer 3, which may be, for example, an engine providing propulsion for the floating structure or an electric generator providing electricity to the floating structure.

[0040] Tank 2 is configured to ensure sealing and thermal insulation with respect to the liquid gas it contains. However, over time, the liquid gas in tank 2 partially evaporates, leading to an increase in the saturation pressure of tank 2. The supply system 1 therefore prevents a potential overpressure within tank 2 by venting the gas in vapor form from it.

[0041] To this end, the supply system 1 includes a first supply circuit 4 extending between the tank 2 and the gas-consuming device 3. The first supply circuit 4 includes a compression device 5 configured to draw in the gas in vapor form present in the tank 2. In addition, the compression device 5 is also configured to increase the pressure of the gas in vapor form so that it has a pressure compatible with the requirements of the gas-consuming device 3. The first supply circuit 4 thus makes it possible, on the one hand, to regulate the saturation pressure of the tank 2 and, on the other hand, to supply fuel to the gas-consuming device 3, the latter being, of course, compatible with the nature of the gas contained in the tank 2.

[0042] The supply system 1 also includes a return line 6 connected to the first supply circuit 4 downstream of the compression device 5 and extending to the tank 2. The return line 6 is used in the event of excess gas in vapor form compared to the supply requirements of the gas-consuming device 3. The excess gas is then returned to the tank 2 via the return line 6, but not without having been previously cooled.

[0043] As such, the supply system 1 includes a heat exchanger 7 configured to operate a heat exchange between the gas in the vapor state circulating in the first supply circuit 4 and the gas in the vapor state circulating in the return line 6 and thus to cool the latter before its return to the tank 2.

[0044] The supply system 1 also includes a second supply circuit 8 which is used when the gas in vapor state is present in too small a quantity to cover the supply requirements of the gas-consuming device 3. The second supply circuit 8 can therefore be used in combination with the first supply circuit 4 or alone in the event of a total absence of gas in vapor state in the tank 2.

[0045] The second supply circuit 8 includes a pump 9 located at the bottom of the tank 2 and allowing the extraction of gas in liquid form from the tank 2. The supply system 1 also includes an evaporation device 10 ensuring The evaporation of the gas in its liquid state circulating in the second supply circuit 8 occurs before it is supplied to the gas-consuming device 3, which only accepts gas in its vapor state. Evaporation can, for example, be achieved through heat exchange with a third fluid, such as seawater.

[0046] Such a supply system 1 thus includes several supply means as well as a cooling means before a return to tank 2. All of these means therefore require a significant number of pipes and this can lead to a problem of mechanical congestion, for example during the installation of a section of the supply system to complete the latter within a given floating structure.

[0047] The supply system 1 according to the invention solves this problem of mechanical bulk by bringing together a part of the return line 6 and a part of the second supply circuit 8 in a common section 11. In other words, the common section 11 is both part of the return line 6 and of the second supply circuit 8, thus limiting the number of pipes required for the proper functioning of the supply system 1. More particularly, the common section 11 is located downstream of the heat exchanger 7 from the point of view of the return line 6, and upstream of the evaporation device 10 from the point of view of the second supply circuit 8, the downstream and upstream characteristics being compared according to the same direction of flow.

[0048] For example, during the installation of the return line 6 and the heat exchanger 7 within a floating structure already equipped with the first supply circuit 4 and the second supply circuit 8, it is possible to partially use the piping of the second supply circuit 8 to form the common section 11 when implementing the return line 6 and thus limit the number of piping within the supply system 1. This therefore allows for cost savings and a limitation of mechanical bulk.

[0049] The combination of the return line 6 and the second supply circuit 8 is particularly advantageous, since they are never used simultaneously. Indeed, the return line 6 is used in the event of an excess of gas in the vapor state in tank 2, while the second supply circuit 8 is used in the event of a lack or absence of gas in the vapor state in tank 2. The return line 6 and the second supply circuit 8 can therefore be combined in the common section 11 without this causing interference with their respective operation.

[0050] It is thus understood that the common section 11 is configured to ensure the circulation of the gas in two directions depending on the activity of the return line 6, ensuring the circulation of the gas towards the tank 2, or the activity of the second supply circuit 8, ensuring the circulation of the gas from the tank 2. At this title, the common portion 11 includes a first end 12 and a second end 13, corresponding to the delimitations of the common portion 11, from which the return line 6 and the second supply circuit 8 are separated from each other.

[0051] By way of example, as illustrated in [Fig. 1] and in the following figures, the first end 12 corresponds to the end of the distal common portion 11 of the tank 2, while the second end 13 corresponds to the end of the proximal common portion 11 of the tank 2. The gas can therefore flow in a first direction of flow 14 from the first end 12 to the second end 13, or in a second direction of flow 15 from the second end 13 to the first end 12. Thus, the gas flows in the common portion 11 in the first direction of flow 14 when said gas flows in the return line 6, and the gas flows in the common portion 11 in the second direction of flow 15 when said gas flows in the second supply circuit 8.

[0052] In order to further control the flow of gas within, in particular, the common section 11, the supply system 1 includes at least one control device 22 authorizing or prohibiting the flow of gas at the level of the circuit or line on which said control device 22 is located.

[0053] According to the example illustrated in [Fig. 1], the supply system 1 comprises a plurality of control elements 22. More particularly, the supply system 1 comprises a first control element 22a disposed on the return line 6 between the heat exchanger 7 and the first end 12 of the common section 11 and a second control element 22b disposed on the second supply circuit 8 between the first end 12 of the common section 11 and the evaporator device 10. According to an example illustrated in Figures 1 to 3, the first control element 22a and the second control element 22b are valves that can be opened or closed depending on the gas flow and the purpose of this flow.

[0054] The return line 6 includes a branch 16 extending between the second end 13 of the common portion 11 and the tank 2. This branch 16 allows the return of the gas into the tank 2 without interfering with the pump 9 of the second supply circuit 8. As such, the branch 16 may also include a third control element 22c also in the form of a valve and being able to switch to the open or closed position depending on the gas circulation and the purpose of this circulation.

[0055] According to the first embodiment of the feed system 1, the branch 16 extends to the tank 2 and includes an ejector 17 immersed at the bottom of the tank 2. The ejector 17 ensures mixing between the gas in the vapor state circulating in the return line 6 and the gas in the liquid state from the bottom of the tank 2, so that the gas in the vapor state or released at the bottom of tank 2 in liquid form. This configuration can lead to an increase in the overall temperature of the liquid gas contained in tank 2. To counteract this, refrigeration methods (not shown) can compensate for this temperature increase by cooling the liquid gas in tank 2.

[0056] Furthermore, the second supply circuit 8 includes a fourth control element 22d disposed between the pump 9 and the second end 13 of the common section 11. The fourth control element 22d is in the form of a check valve preventing the circulation of gas in a direction of flow from the second end 13 of the common section 11 towards the pump 9, thus optimizing the circulation of the gas from the return line 6 and forcing it to flow within the branch 16.

[0057] Figures 2 and 3 illustrate the gas flow in the first embodiment of the supply system 1, respectively when the gas in vapor form present in tank 2 is present in excess of the requirements of the gas-consuming device 3 and when there is too little or no gas in vapor form in tank 2 to adequately supply it. In [Fig. 2], the first control element 22a and the third control element 22c allow gas flow, while the second control element 22b prohibits gas flow. Conversely, in [Fig. 3], the first control element 22a and the third control element 22c prohibit gas flow, while the second control element 22b allows gas flow.

[0058] For figures 2 and 3, the portions of the supply system 1 through which gas flows in liquid or vapor state are represented by solid lines, while the portions of the supply system 1 without gas flow are represented by dashed lines.

[0059] Figure 2 is an example of gas circulation where the gas in the vapor state is present in excess in the tank 2. The gas in the vapor state is therefore drawn in by the compression device 5 and circulates in the first supply circuit 4. Initially, the gas in the vapor state passes through the heat exchanger 7 in order to cool the gas in the vapor state circulating in the return line 6. At the outlet of the heat exchanger 7, the gas in the vapor state circulating in the first supply circuit 4 is then compressed by the compression device 5 to a pressure compatible with the requirements of the gas-consuming device 3.

[0060] The gas in vapor form then flows to the gas-consuming device 3 to supply it. The quantity of gas in vapor form supplied to the gas-consuming device 3 depends on its supply requirements. The excess gas in vapor form flows in the return line 6 from the outlet of the compression device 5. [Fig. 2] illustrates a gas flow in the steam up to the gas-consuming device 3, but it is also possible that the gas-consuming device 3 does not require any supply of gas in the vapor state, in which case all of the gas in the vapor state compressed by the compression device 5 flows within the return line 6 thereafter.

[0061] The gas in the vapor state circulating in the return line 6 passes through the heat exchanger 7. As the gas in the vapor state circulating in the return line 6 has been previously compressed by the compression device 5, said gas is at a higher temperature than the gas in the vapor state exiting the tank 2 and circulating in the first supply circuit 4. The gas in the vapor state circulating in the return line 6 is therefore cooled by passing through the heat exchanger 7.

[0062] The gas in the vapor state continues its circulation until it reaches the first end 12 of the common portion 11 before circulating in the latter in the first direction of circulation 14 until the second end 13. The gas in the vapor state then circulates within the branch 16 and is ejected to the bottom of the tank 2 by the ejector 17.

[0063] Fig. 3 represents the opposite configuration to Fig. 2, i.e. the gas in vapor state is present in too small a quantity, or even absent, to meet the supply requirements of the gas-consuming device 3.

[0064] If gas in vapor form is present in tank 2, it flows through the first supply circuit 4, then passes through the heat exchanger 7 without consequence or bypasses it by flowing through a bypass line (not shown). The gas in vapor form is then compressed by the compression device 5 and continues its flow through the first supply circuit 4 until it supplies the gas-consuming device 3. Since there is no excess gas in vapor form, there is no gas flow through the return line 6. If there is no gas in vapor form present in tank 2, then there is no gas flow through the first supply circuit 4.

[0065] In this configuration, the lack of gas in vapor form to meet the needs of the gas-consuming device 3 is therefore compensated by means of the second supply circuit 8. To do this, the pump 9 draws the gas present in liquid form from the tank 2. The gas in liquid form flows to the second end 13 of the common section 11 before flowing in the latter in the second direction of flow 15 to the first end 12.

[0066] The gas in liquid state then continues its circulation in the second supply circuit 8 until it is evaporated within the evaporation device 10. At the outlet of the latter, the evaporated gas circulates in the second supply circuit 8 until it supplies the gas-consuming device 3.

[0067] Figure 4 represents a second embodiment of the power supply system 1 according to the invention. The second embodiment differs from the first embodiment in implementation in particular in that the gas in vapor state circulating in the return line 6 is reliquefied before returning to the tank 2.

[0068] For this purpose, the heat exchanger 7 shown in figures 1 to 3 for the first embodiment is here a first heat exchanger 18, always configured to operate a heat exchange between the gas in the vapor state circulating in the first supply circuit 4 and the gas in the vapor state circulating in the return line 6.

[0069] The second embodiment of the supply system 1 further includes a cooling circuit 19 comprising a pumping device 20 configured to draw gas in the liquid state from the tank 2. Finally, the second embodiment of the supply system 1 includes a second heat exchanger 21 configured to perform a heat exchange between the gas in the vapor state circulating in the return line 6 and the gas in the liquid state circulating in the cooling circuit 19. It is therefore within this second heat exchanger 21 that the gas in the vapor state circulating in the return line is reliquefied before returning to the tank 2.

[0070] At the outlet of the second heat exchanger 21, the reliquefied gas circulating in the return line 6 and the gas in liquid state circulating in the cooling circuit 19 join upstream of the first end 12 of the common portion 11 before circulating to the tank 2. As the gas is completely reliquefied, the second embodiment of the supply system 1 does not include an ejector at the branch 16, but an orifice opening at the bottom of the tank 2.

[0071] It is thus understood that the gas in the vapor state circulating in the return line 6 is first cooled within the first heat exchanger 18, then liquefied within the second heat exchanger 21.

[0072] Another difference between the illustrations of the two embodiments of the supply system 1 according to the invention is that the supply system 1 illustrated in [Fig. 4] is configured to supply gas to a first gas-consuming device 3a and a second gas-consuming device 3b. As previously mentioned, the first gas-consuming device 3a can be an engine providing propulsion for the floating structure, while the second gas-consuming device 3b can be an electric generator providing electricity to the floating structure. Advantageously, the first gas-consuming device 3a and the second gas-consuming device 3b have the same compatibility in terms of the gas pressure supplying them, i.e., the pressure applied to the gas by the compression device 5 or by the pump 9.

[0073] The first supply circuit 4 and the second supply circuit 8 are therefore both capable of supplying the first gas-consuming appliance 3a and / or the second gas-consuming appliance 3b, depending on the needs of each. of them. Such a configuration is not specific to the second embodiment and it is therefore possible to supply two gas-consuming appliances 3a, 3b or more using the first embodiment of the supply system 1, or to supply a single gas-consuming appliance 3 using the second embodiment of the supply system 1.

[0074] Finally, the second embodiment of the supply system 1 differs from the first embodiment in that the first control element 22a and the second control element 22b are in the form of check valves. The check valves allow gas to flow in one direction, but not in the opposite direction, thus ensuring operation similar to that of the valves illustrated in Figures 1 to 3. The type of control element 22 is, however, independent of the embodiment, and it is therefore possible to implement either valves or check valves regardless of the embodiment. The third control element 22c and the fourth control element 22d are, respectively, always a valve and a check valve.

[0075] Since the structural and functional elements not described for this second embodiment of the power supply system 1 are identical to those of the first embodiment, reference will be made to the description of [Fig.1] concerning the elements common to the two embodiments.

[0076] Figures 5 and 6 represent the gas circulation in the second embodiment of the supply system 1, respectively when the gas in the vapor state present in the tank 2 is present in excess of the needs of the gas-consuming device(s) 3a, 3b and when there is too little or no gas in the vapor state in the tank 2 to sufficiently supply the device(s).

[0077] Just as for figures 2 and 3, for figures 5 and 6 the portions of the supply system 1 through which gas flows in the liquid or vapor state are represented by solid lines, while the portions of the supply system 1 without gas circulation are represented by dashed lines.

[0078] Figure 5 is an example of gas circulation where the gas in the vapor state is present in excess in the tank 2. The gas in the vapor state is therefore drawn in by the compression device 5 and circulates in the first supply circuit 4. Initially, the gas in the vapor state passes through the heat exchanger 7 in order to cool the gas in the vapor state circulating in the return line 6. At the outlet of the heat exchanger 7, the gas in the vapor state circulating in the first supply circuit 4 is then compressed by the compression device 5 to a pressure compatible with the requirements of the gas-consuming devices 3a, 3b.

[0079] The gas in vapor form then flows to the first gas-consuming device 3a and / or to the second gas-consuming device 3b to supply them. Depending on the requirement, the first supply circuit 4 can supply only one of the two gas-consuming devices 3a, 3b, or both simultaneously. Such a configuration can be regulated by a valve system (not shown).

[0080] The excess gas in vapor state flows in the return line 6 at the outlet of the compression device 5. [Fig.5] illustrates a flow of gas in vapor state to the gas-consuming devices 3a, 3b, but it is also possible that the gas-consuming devices 3 do not require any supply of gas in vapor state, in which case all of the gas in vapor state compressed by the compression device 5 flows in the return line 6 thereafter.

[0081] The gas in the vapor state circulating in the return line 6 passes through the heat exchanger 7. As the gas in the vapor state circulating in the return line 6 has been previously compressed by the compression device 5, said gas is at a higher temperature than the gas in the vapor state exiting the tank 2 and circulating in the first supply circuit 4. The gas in the vapor state circulating in the return line 6 is therefore cooled by passing through the heat exchanger 7.

[0082] The gas in the vapor state thus cooled then circulates within the second heat exchanger 21. In parallel, gas in the liquid state circulates within the cooling circuit 19 by means of the pumping device 20 and also circulates within the second heat exchanger 21 in order to liquefy the previously cooled gas in the vapor state.

[0083] At the outlet of the second heat exchanger 21, the reliquefied gas and the gas in the liquid state circulating in the cooling circuit 19 join together and continue their circulation until they reach the first end 12 of the common section 11 before circulating in the latter in the first direction of circulation 14 until the second end 13. The mixture of reliquefied gas and gas in the liquid state from the cooling circuit 19 then circulates within the branch 16 to the bottom of the tank 2.

[0084] Fig. 6 represents the opposite configuration to Fig. 5, i.e. the gas in vapor state is present in too small a quantity, or even absent, to meet the supply requirements of one or both of the gas-consuming devices 3a, 3b.

[0085] If gas in vapor form is present in tank 2, it circulates in the first supply circuit 4, then passes through the heat exchanger 7 without consequence or bypasses it by circulating within a bypass line not shown. The gas in vapor form is then compressed by the compression device 5 and continues its circulation in the first supply circuit 4. until supplying one or both of the gas-consuming devices 3a, 3b. As there is no excess gas in vapor form, there is no gas circulation within the return line 6. Therefore, in the absence of gas in vapor form to liquefy, there is also no gas circulation in liquid form within the cooling circuit 19. If there is no gas in vapor form present in tank 2, then there is no gas circulation in the first supply circuit 4.

[0086] In this configuration, the lack of gas in vapor form to meet the needs of one or both of the gas-consuming devices 3a, 3b is therefore compensated by means of the second supply circuit 8. To do this, the pump 9 draws the gas present in liquid form from the tank 2. The gas in liquid form flows to the second end 13 of the common section 11 before flowing in the latter in the second direction of flow 15 to the first end 12.

[0087] The gas in liquid state then continues its circulation in the second supply circuit 8 until it is evaporated within the evaporation device 10. At the outlet of the latter, the evaporated gas circulates in the second supply circuit 8 until it supplies the first gas-consuming device 3a and / or the second gas-consuming device 3b.

[0088] Figure 7 represents a variant of the first embodiment of the feeding system 1 according to the invention. This variant consists of applying the feeding system 1 to a floating structure comprising a plurality of tanks 2a, 2b. In Figure 7, a first tank 2a and a second tank 2b are illustrated, but the feeding system 1 is applicable to a floating structure comprising more tanks.

[0089] The first supply circuit 4 is thus fluidly linked to each of the tanks 2a, 2b, allowing the compression device 5 to draw the gas in the vapor state present in the two tanks 2a, 2b.

[0090] The return line 6 is also fluidly connected to the two tanks 2a, 2b, each of them interacting with its own branch 16a, 16b, both connected to the common portion 11, as well as its own ejector 17a, 17b. In other words, there are as many branches 16a, 16b and ejectors 17a, 17b as there are tanks 2a, 2b.

[0091] Figure 7 illustrates a variant concerning the branch 16b interacting with the second tank 2b. The branch 16b is configured to be immersed within the second tank 2b, unlike the branch 16a, which overhangs the first tank 2a, as illustrated previously. This variant positioning of the branch 16b allows the internal volume of the second tank 2b to be used to integrate said branch 16b and thus avoids further encumbering the space dedicated to the feed system 1 with the branch 16b pipes. It should be noted that this variant is also applicable to the second embodiment described above.

[0092] Finally, regarding the second supply circuit 8, this is also fluidly linked to the two tanks 2a, 2b, each of them interacting with its own pump 9a, 9b, both connected to the common portion 11.

[0093] As illustrated in [Fig. 7], the supply system 1 still comprises only a single common section 11 despite the presence of two tanks 2a, 2b. It is thus clear that the advantage of the supply system 1 according to the invention is significant when the floating structure comprises a plurality of tanks, since the more tanks there are, the more piping there is. Implementing a common section 11 for the return line 6 and the second supply circuit 8 can therefore greatly reduce the mechanical footprint of the supply system 1 when several tanks are present within the floating structure.

[0094] The various gas flows detailed in Figures 2 and 3 are also applicable to [Fig. 7]. The gas can be drawn off or returned to one and / or the other of the tanks 2a, 2b depending on various parameters such as the volume of tanks 2a, 2b, the quantity of gas present in each of the tanks 2a, 2b or their temperature.

[0095] It is also evident that the second embodiment of the supply system 1 according to the invention is also applicable for a floating structure comprising a plurality of tanks 2a, 2b.

[0096] Of course, the invention is not limited to the examples just described and many modifications can be made to these examples without departing from the scope of the invention.

[0097] The invention, as described above, achieves its intended purpose and provides a gas supply system for at least one gas-consuming appliance on a floating structure, said supply system guaranteeing a limited number of pipes required for its proper operation. Variations not described here could be implemented without departing from the scope of the invention, provided that, in accordance with the invention, they include a supply system conforming to the invention.

Claims

Demands

1. A gas supply system (1) for at least one gas-consuming appliance (3, 3a, 3b) of a floating structure comprising at least one tank (2) configured to contain the gas, the supply system (1) comprising: - at least one first gas supply circuit (4) for the gas-consuming appliance (3, 3a, 3b) comprising at least one compression device (5) configured to compress gas taken in vapor form from the tank (2) to a pressure compatible with the requirements of the gas-consuming appliance (3, 3a, 3b), - a gas return line (6) connected to the first supply circuit (4) downstream of the compression device (5) and extending to the tank (2), the supply system (1) comprising at least one heat exchanger (7) configured to perform heat exchange between the gas circulating in the first supply circuit (4) and the gas circulating in the return line (6),- at least one second gas supply circuit (8) for the gas-consuming appliance (3, 3a, 3b), comprising at least one pump (9) configured to pump the gas drawn in liquid form from the tank (2) and at least one evaporation device (10) configured to vaporize the gas in liquid form, characterized in that the return line (6) and the second supply circuit (8) share a common section (11), the common section (11) being configured to circulate gas in a first direction of flow (14) or in a second direction of flow (15) opposite to the first direction of flow (14).

2. Feeding system (1) according to claim 1, wherein the common portion (11) is connected between the heat exchanger (7) and the evaporation device (10).

3. A supply system (1) according to claim 1 or 2, wherein the common portion (11) comprises a first end (12) and a second end (13) from which the return line (6) and the second supply circuit (8) branch off, the common portion (11) being configured to circulate the circulating gas in the return line (6) in the first direction of flow (14) from the first end (12) to the second end (13), and to circulate the gas flowing in the second supply circuit (8) in the second direction of flow (15) from the second end (13) to the first end (12).

4. Feeding system (1) according to claim 3, wherein the return line (6) includes a branch (16) configured to extend from the second end (13) of the common portion (11) to a bottom of the tank (2).

5. Feeding system (1) according to claim 4, wherein the branch (16) includes an ejector (17) configured to be arranged at the bottom of the tank (2).

6. Feed system (1) according to any one of claims 1 to 5, wherein the heat exchanger (7) is a first heat exchanger (18), the feed system (1) comprising a cooling circuit (19) and a second heat exchanger (21), the cooling circuit (19) comprising a pumping device (20) configured to pump the gas taken in liquid form from the tank (2), the second heat exchanger (21) being configured to operate a heat exchange between the gas in vapor form flowing in the return line (6) and the gas in liquid form flowing in the cooling circuit (19).

7. Feeding system (1) according to the preceding claim, wherein the first heat exchanger (18) is configured to cool the gas in the vapor state flowing in the return line (6) while the second heat exchanger (21) is configured to liquefy the gas in the vapor state flowing in the return line (6).

8. Supply system (1) according to claim 6 or 7, in combination with claim 3, wherein the cooling circuit (19) and the return line (6) join downstream of the second heat exchanger (21) and upstream of the first end (12) of the common portion (11).

9. Supply system (1) according to any one of the preceding claims, in combination with claim 4, comprising at least one control element (22, 22a, 22b, 22c, 22d) configured to control the flow of gas within the return line (6) and / or the second supply circuit (8) and / or the branch (16).

10. Floating structure for the transport and / or storage of gas in liquid state, comprising at least one tank (2) configured to contain the gas, at least one gas-consuming device (3) and at least one supply system (1) according to any one of the preceding claims.

11. A method for supplying at least one gas-consuming appliance (3, 3a, 3b) to a floating structure comprising at least one tank (2) configured to contain the gas, implemented by a supply system (1) according to any one of claims 1 to 9, wherein: - when a quantity of gas in vapor state contained in the tank (2) is greater than the supply requirement of the gas-consuming appliance (3, 3a, 3b), the gas-consuming appliance (3, 3a, 3b) is supplied via the first supply circuit (4) from the gas in vapor state contained in the tank (2), an excess of gas in vapor state circulating in the return line (6), the excess gas circulating in the common section (11) according to a first direction of circulation (14), - when a quantity of gas in vapor state contained in the tank (2) is less than the supply requirement of the gas-consuming appliance (3, 3a, 3b), the gas-consuming appliance (3, 3a, 3b) is supplied at least via the second supply circuit (8) from the gas in liquid state contained in the tank (2), the gas in liquid state circulating in the common portion (11) in a second direction of circulation (15) opposite to the first direction of circulation (14).

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