STORAGE FACILITY FOR A LIQUID-STATE GAS COMPRISING A TANK AND A SUCTION DEVICE OF AN INSULATION LAYER OF SAID TANK

Abstract

A storage facility includes a tank for transporting and/or storing gas in a liquid state, the tank including at least one insulation layer, a gas-consuming device, and one device for suctioning the gas present in the insulation layer. The suction device includes a primary branch fluidly connected to the gas-consuming device, at least one secondary branch fluidly connected to the insulation layer of the tank and through which the gas from the insulation layer flows, and at least one suction member configured to suction the gas flowing through the secondary branch.

Claims

1-12. (canceled)

13. A storage facility for gas in a liquid state comprising: at least one tank for transporting and/or storing the gas in the liquid state, the tank including at least one insulation layer; at least one gas-consuming device; and at least one device for suctioning gas present in the insulation layer, the suction device including at least one primary branch fluidly connected to the gas-consuming device, at least one secondary branch fluidly connected to the insulation layer of the tank and through which the gas from the insulation layer flows, and at least one suction member configured to suction the gas flowing through the secondary branch.

14. The storage facility according to claim 13, wherein the primary branch is flowed through by drive gas.

15. The storage facility according to claim 14, wherein the drive gas is dinitrogen.

16. The storage facility according to claim 14, wherein the suction member is an ejector comprising a first inlet connected to the primary branch, a second inlet connected to the secondary branch, and an outlet fluidly connected to the gas-consuming device, the ejector being supplied with the drive gas.

17. The storage facility according to claim 14, wherein the suction member is a compression member which suctions the gas flowing through the secondary branch, the compression member comprising an outlet port fluidly connected to the gas-consuming device.

18. The storage facility according to claim 17, wherein the compression member is supplied with the drive gas.

19. The storage facility according to claim 17, wherein the compression member comprises a compressor and an electrical source supplying the compressor.

20. The storage facility according to claim 13, wherein the secondary branch comprises a non-return valve arranged between the insulation layer and the suction member.

21. The storage facility according to claim 13, comprising a circuit for inerting the insulation layer, the secondary branch being connected to the inerting circuit, the inerting circuit comprising a valve isolating the secondary branch from the inerting circuit.

22. The storage facility according to claim 13, comprising at least two suction devices, the tank comprising a first insulation layer in contact with the gas in the liquid state contained in the tank and a second insulation layer surrounding the first insulation layer, the secondary branch of a first suction device being fluidly connected to the first insulation layer, the secondary branch of a second suction device being fluidly connected to the second insulation layer.

23. The storage facility according to claim 13, wherein the suction member is configured to suction in at most 14 m.sup.3 of gas per hour within +/25%.

24. The storage facility according to claim 13, wherein the gas-consuming device is selected from an internal combustion engine, a gas boiler, a gas combustion unit, and an electricity generator.

Description

[0026] Other features and advantages of the invention will appear both from the description which follows and from several exemplary embodiments, which are given for illustrative purposes and without limitation with reference to the appended schematic drawings, in which:

[0027] FIG. 1 is a schematic diagram of a storage facility for a gas in a liquid state according to the invention,

[0028] FIG. 2 shows a tank for transporting and/or storing gas in a liquid state and a device for suctioning an insulation layer of the storage facility shown in FIG. 1,

[0029] FIG. 3 represents an alternative installation of the storage facility according to the invention.

[0030] FIG. 1 shows a storage facility 1 for a gas in a liquid state, which comprises at least one tank 2 for transporting and/or storing gas in a liquid state. In FIG. 1, three tanks 2 are shown, but the storage facility 1 can contain any number of tanks 2. In FIG. 1, the storage facility 1 shown is a vessel. The liquid-state gas contained in the tanks 2 may, for example, be a cargo to be transported by the vessel to a given destination. The liquid-state gas can also be a simple fuel for the vessel whose function is other than to transport a cargo of gas in its liquid state. According to other examples, the storage facility 1 can also be a floating liquefaction unit, a regasification unit, a floating storage barge or a gravity platform ensuring the storage of gas in a liquid state.

[0031] The storage facility 1 comprises at least one gas-consuming device 3. That device can, for example, be an internal combustion engine ensuring the propulsion of the storage facility 1 if it is intended to move. The gas-consuming device 3 can also be an electricity generator providing power to the storage facility 1, a gas boiler producing steam as energy for a third-party consumer, or a gas combustion unit configured to burn gas. The gas-consuming device 3 is able to consume the vaporous gas contained in the tanks 2 as fuel. When the gas has to be in the vapor state to be consumed, the liquid-state gas contained in the tank 2 can be evaporated. The evaporation of the gas can be the result of a natural evaporation of the gas in a liquid state formed in a headspace of the tanks 2 or a forced evaporation in order to obtain fuel for the gas-consuming device 3. The storage facility 1 according to the invention may be able to use the gas evaporated from the headspace of the tanks 2 or the liquid-state gas once vaporized, and is characterized in that it comprises a suction device 4 which is able to suction the vapor-state gas located within an insulation layer of at least one of the tanks 2. The gas in the vapor state may sometimes find its way into the insulation layer of one of the tanks 2 in the exceptional event that a leak occurs in said tank 2. The suction device 4 is then able to suction this gas in the leaking vapor state and circulate it to the gas-consuming device 3 to supply same with fuel. The storage facility 1 according to the invention at least limits the loss of gas as a result of a leakage, and in the case of a minor leakage with a relatively low flow rate can at least partially suction the leaking gas, thus avoiding a loss of the leaking gas. All of the gas suctioned by the suction device 4 is used as fuel and fed to the gas-consuming device 3.

[0032] FIG. 2 shows a tank 2 and a detailed suction device 4 to better describe same. FIG. 2 also shows the insulation layers 5 of the tank 2. More specifically, the tank 2 comprises a first insulation layer 51 in contact with the liquid-state gas 22 contained in the tank 2 and a second insulation layer 52 surrounding the first insulation layer 51.

[0033] Each insulation layer 5 comprises a waterproof membrane for sealing the insulation layer 5 and a thermal insulation layer of thermally insulating boxes or panels for thermal insulation of the liquid gas 22. The presence of two layers of insulation 5 ensures the reinforcement of the safety of the gas cargo in a liquid state 22 as well as its maintenance at low temperature.

[0034] As mentioned above, despite all the precautions taken, a leakage of the first layer of insulation 51 may occur in exceptional cases. In case of a major leak, it is quickly detected and an emergency procedure can be implemented to ensure the safety of the storage facility and its crew. If the leak is minor, it may be difficult to locate, and the leakage rate is relatively small but should not be overlooked. The suction device 4 is thus adapted to address the problem of leaking gas within the first insulation layer 51 in the case of a minor leak.

[0035] For this purpose, the suction device 4 comprises a primary branch 6, a secondary branch 7, and a suction member 8. The primary branch 6 is fluidly connected to the aforementioned gas-consuming device 3 while the secondary branch 7 is fluidly connected to the first insulation layer 51.

[0036] The suction member 8, as shown in FIG. 2, is an ejector 9. The ejector 9 implements a pressure differential to generate a suction. For this purpose, the ejector comprises a first inlet 10, a second inlet 11, and an outlet 12. The first inlet 10 and the outlet 12 are connected to the primary branch 6, while the second inlet 11 is connected to the secondary branch 7. The primary branch 6 is further fluidly connected to a drive gas source 19 which circulates a drive gas through the primary branch 6. The drive gas flows through the ejector 9 via the first inlet 10 and then through the outlet 12. The properties of the ejector 9 allow to lower the pressure of the drive gas passing through it and to create a pressure differential which leads to suction at the second inlet 11 and thus at the secondary branch 7.

[0037] Thus, if a leakage causes gas evaporation within the first insulation layer 51 or a leakage of gas in the vapor state, the gas is suctioned into the secondary branch 7 and flows to the ejector 9 via the second inlet 11 thanks to the pressure differential generated by the passage of the drive gas. The suctioned exhaust gas then mixes with the drive gas in the ejector 9. The mixture exits the ejector via the outlet 12 and flows to the gas-consuming device 3, which consumes the suctioned gas. The suction member 4 is configured to suction a maximum of 14 m.sup.3 of gas per hour within +/25%, which can at least partially compensate for the gas flow in the first insulation layer 51 in case of a minor leak.

[0038] The drive gas must flow in small quantities through the primary branch 6 so as not to affect the correct operation of the gas-consuming device 3. As an example, an LNG vessel engine consumes about 1800 m.sup.3/hour of gas at a speed of about 12 knots. The drive gas can be, for example, dinitrogen. The advantage of dinitrogen is that a dinitrogen flow can be implemented throughout the storage facility for various functions, for example for use as an inert gas, including in the vicinity of the tanks 2 and the gas-consuming device 3. It is therefore easy to divert the flow of dinitrogen for use in the suction device 4. In FIG. 2, only one gas-consuming device 3 is supplied, but the suction device can supply a plurality of gas-consuming devices 3.

[0039] The secondary branch 7 comprises a non-return valve 15 between the first insulation layer 51 and the suction member 8. The non-return valve 15 allows the flow of gas drawn from the first insulation layer 51 to the suction member 8 and prevents the flow of gas in the opposite direction. The non-return valve 15 thus prevents a backflow of drive gas to the first insulation layer 51.

[0040] The storage facility further comprises an inerting circuit 16 which makes it possible, in particular, to renew the inert gas within the insulation layers 5 and also to evacuate potential hydrocarbons or ammonia or dihydrogen present in these same insulation layers 5. For this purpose, an inerting gas, namely dinitrogen, is circulated by a dinitrogen source 20 within the insulation layers 5, in this case the first insulation layer 51. The gas contained in the latter is then suctioned and circulates in the inerting circuit 16 in order to be sent to the atmosphere 27 afterwards.

[0041] The storage facility may comprise an analysis module 21, connected to the inerting circuit 16, which analyzes the gas suctioned through the inerting circuit 16 for potential hydrocarbons or ammonia or dihydrogen, which are signs of a leak within the first insulation layer 51.

[0042] As the inerting circuit 16 is potentially integrated within the storage facility in question, it is possible to use it partially to set up the suction device 4. For example, it is useful to use the pipe opening within the first insulation layer 51 for both the inerting circuit 16 and the suction device 4, as shown in FIG. 2. The drive gas source 19 and the dinitrogen source 20 can also be one and the same source.

[0043] In order to isolate the inerting circuit 16 from the suction device 4, the storage facility may comprise a valve 17 positioned at the secondary branch 7 and an additional valve 26 positioned at the inerting circuit 16. When inerting of the first insulation layer 51 is required, the additional valve 26 is opened and the valve 17 is closed so that the gas flowing through the inerting circuit 16 flows to the atmosphere 27. When the suction device 4 is operated, the valve 17 is open and the additional valve 26 is closed so that the suction member 8 can suction the gas circulating through the first insulation layer 51. The opening and/or closing of the valve 17 and additional valve 26 can be implemented depending on whether gas is detected by the analysis module 21.

[0044] FIG. 3 shows an alternative installation of the storage facility according to the invention, in particular of the suction member 8 and the surrounding pipework of the tank 2. Only those features that differ from those described in FIG. 2 will be described here and reference will be made to the description of FIG. 2 for features common to FIGS. 2 and 3.

[0045] The variant differs from the one described in FIG. 2 in that the storage facility comprises two suction devices 4, namely a first suction device 41 suctioning gas into the first insulation layer 51 and a second suction device 42 suctioning gas into the second insulation layer 52, in the exceptional case that a leakage leads to the presence of gas in a liquid or gaseous state within the two insulation layers 5. The elements of the suction device 4 are thus all doubled so that each of the insulation layers 5 can be treated by one of the suction devices 4. In FIG. 3, the two suction devices 4 are fluidly connected to one and the same gas-consuming device 3, but it is possible that each suction device 4 is fluidly connected to its own gas-consuming device 3.

[0046] The inerting circuit 16 can also be doubled in order to inject dinitrogen within the two insulation layers 5. Thus, in FIG. 3, two sources of dinitrogen 20 are shown, as well as two outlets to the atmosphere 27, each of the inerting circuits 16 managing one of the two insulation layers 5. The storage facility may also comprise two analysis modules 21, each connected to one of the inerting circuits 16. Each analysis module 21 has the function of detecting gases in its own insulation layer 5.

[0047] According to the variant shown in FIG. 3, the suction member 8 of the first suction device 41 and the suction member 8 of the second suction device 42 are a compression member 13.

[0048] The compression member 13 of the first suction device 41 comprises a compressor 24 and an electrical source 25. The electrical source 25 supplies power to the compressor 24 to ensure its operation, for example in rotation, and thus suctions the gas via the secondary branch 7. The compressor 24 comprises an outlet port 14 where the suctioned gas exits to supply the gas-consuming device 3.

[0049] As with the ejector 9 shown in FIG. 2, the compression member 13 of the second suction device 42 is also supplied with drive gas. It is the latter that drives the operation of the compression member 13, for example in rotation, and ensures the suction of the gas potentially present in the second insulation layer 52. Like the compressor 24, the compressor 13 has an outlet port 14 from which the intake gas and the drive gas exit in order to flow to the gas-consuming device 3. As shown in FIG. 2, the drive gas is derived from the drive gas source 19.

[0050] Each of the suction devices 4 shown in FIG. 3 may incorporate any of the suction members 8 described above, namely the ejector described in FIG. 2 or one of the compression members 13. Similarly, the suction device described in FIG. 2 is also functional if the suction member 8 is one of the compression members 13 shown in FIG. 3.

[0051] Of course, the invention is not limited to the examples that have just been described, and numerous modifications can be made to these examples without departing from the scope of the invention.

[0052] The invention, as just described, achieves its intended purpose and makes it possible to propose a storage facility comprising a tank of gas in a liquid state, a gas-consuming device and a suction device for suctioning the gas leaking from the tank in order to feed it to the gas-consuming device. Variants not described here could be implemented without departing from the context of the invention, since, in accordance with the invention, they comprise a storage facility according to the invention.