LIQUEFIED GAS STORAGE TANK

Abstract

A tank for storing liquefied gas, having a shell delimiting a storage volume extending in a main direction which is horizontal in the use configuration of the tank, the tank comprising multiple deflecting walls in the storage volume which extend in an offset manner in the main direction configured to force the fluid to perform at least one back-and-forth movement in the main direction as the fluid passes between the lower end and the upper end of the storage volume, wherein a plurality of these deflecting walls are located in the lower half of the storage volume.

Claims

1.-14. (canceled)

15. A tank for storing liquefied gas, comprising a shell delimiting a storage volume extending in a main direction which is horizontal in the use configuration of the tank, the tank comprising multiple deflecting walls in the storage volume which extend in an offset manner in the main direction configured to force the fluid to perform at least one back-and-forth movement in the main direction as the fluid passes between the lower end and the upper end of the storage volume, wherein a plurality of these deflecting walls are located in the lower half of the storage volume.

16. The tank as claimed in claim 1, wherein the deflecting walls extend over part of the storage volume in the main direction from one end of the shell.

17. The tank as claimed in claim 1, wherein the deflecting walls are horizontal or substantially horizontal in the use configuration of the tank.

18. The tank as claimed in claim 1, wherein the deflecting walls extend horizontally through the entire cross section of the storage volume.

19. The tank as claimed in claim 1, further comprising an odd number of deflecting walls.

20. The tank as claimed in claim 1, further comprising a filling and/or withdrawal orifice located in the lower part of one longitudinal end of the shell.

21. The tank as claimed in claim 1, further comprising a filling and/or withdrawal orifice located in the upper part of one longitudinal end of the shell.

22. The tank as claimed in claim 1, further comprising a fluid filling and/or withdrawal orifice located at one longitudinal end and at an intermediate height between the upper and lower parts of the storage volume.

23. The tank as claimed in claim 1, further comprising a deflecting wall perforated with a plurality of orifices.

24. The tank as claimed in claim 1, further comprising a deflecting wall perforated with a plurality of orifices only over part of the surface of said deflecting wall.

25. The tank as claimed in claim 1, wherein the deflecting wall located in the upper part of the storage volume is perforated with a plurality of orifices.

26. The tank as claimed in claim 1, wherein at least some of the deflecting walls are composed of flexible material.

27. The tank as claimed in claim 1, wherein the tank contains liquefied gas and at least some of the deflecting walls are submerged in the liquid phase.

28. A method for storing a cryogenic liquefied gas using a tank as claimed in claim 1, wherein the liquefied gas is stored in the tank with a liquid level located above at least one of the deflecting walls.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] For a further understanding of the nature and objects for the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

[0041] FIG. 1 shows a schematic and partial view in vertical section illustrating a first exemplary embodiment of a tank according to the invention,

[0042] FIG. 2 shows a schematic and partial view in vertical section illustrating a second exemplary embodiment of a tank according to the invention,

[0043] FIG. 3 shows a schematic and partial view in vertical section illustrating a third exemplary embodiment of a tank according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0044] The tank 1, which is shown schematically, is configured for the storage of liquefied gas, in particular liquefied hydrogen.

[0045] This tank comprises a shell 2, for example having a cylindrical overall shape, delimiting a storage volume extending in a main direction A. For example, this main direction A is the longitudinal direction of the tank. The generatrices of the cylindrical part may be parallel to this main direction A or axis. The main direction A may be horizontal in the use configuration of the tank 1. That is to say that the tank 1 may be a tank of the “horizontal” or “vertical” or spherical type (in the latter case, the main direction A may be horizontal) or have any other appropriate form.

[0046] In the schematic representations, only the shell 2 is shown. Of course, the tank 1 may be of the double-walled type with a wall disposed around the shell 2 with formation of a thermally insulated space under vacuum.

[0047] The tank 1 comprises multiple horizontal deflecting walls 3 in the storage volume which extend in an offset manner in the main direction A. These deflecting walls 3 are arranged so as to force the fluid to perform at least one back-and-forth movement in the main direction A as it passes between the lower end and the upper end of the storage volume 2.

[0048] in the examples illustrated, three deflecting walls are provided. Of course, two or more than three walls 3 may be provided.

[0049] The deflecting walls 3 extend over part of the length of the storage volume from one longitudinal end of the shell 2. For example, the deflecting walls 3, taken vertically in succession, are connected alternately to one and then to the other longitudinal end of the shell 2.

[0050] In the case of three deflecting walls 3, as illustrated, this forms three chicanes forcing the fluid to longitudinally change direction three times in order to pass from the top to the bottom of the tank (or vice versa).

[0051] The deflecting walls 3 preferably extend horizontally over the entire cross section of the storage volume and are connected to the shell over their lateral periphery (except at the end referred to as free end, which forms a vertical passage for the fluid).

[0052] These deflecting walls 3 limit the contact or transfer of the liquid at the bottom of the storage volume with the liquid or the vapor at the top of the storage volume.

[0053] This makes it possible to retain a stratified and supercooled liquid in the bottom part of the storage volume. Depending on the fill level, the vapor may also be stratified or non-stratified in accordance with the intended advantages.

[0054] As illustrated in FIG. 2 and FIG. 3, the tank may have a filling or withdrawal orifice 4 located in the lower part of one longitudinal end of the shell 2 and connected to a duct.

[0055] Similarly, the tank may have a filling or withdrawal orifice 5 located in the upper part of one longitudinal end of the shell 2 and connected to a duct.

[0056] In the event of filling being performed from the bottom, the cold liquid arriving through the orifice 4 must flow through the length of the storage volume before being able to rise to the next level, and so on.

[0057] The liquid is reheated and evaporates partially if the walls of the shell 2 are too hot. However, this vapor or this liquid close to equilibrium is forced toward the top of the storage volume by the horizontal deflecting walls without interacting with the cold liquid arriving via the supply.

[0058] The vapor leaving the store is reheated as it rises in the store upon contact with the hot walls (which are cooled).

[0059] When the storage volume is full, the stratification of the liquid is preserved by the deflecting walls and it is possible to limit the stratification of the vapor caused by movements (for transport) or by extracting the vapor for a fixed store.

[0060] This solution makes it possible, where appropriate, also to advantageously replace the “anti-sloshing” walls for preventing liquid sloshing that are traditionally installed in movable tanks. This is because the limitation of the mass of liquid that can be set in motion by the deflecting walls 3 automatically reduces the liquid sloshing effect upon sudden movements.

[0061] As illustrated in FIG. 2 or in FIG. 3, it is possible to provide a return of fluid, preferably with vapor, toward the storage volume interior via an orifice 6 located at an intermediate height between the upper and lower parts of the storage volume.

[0062] This intermediate orifice 6 may be connected to a duct and may be located between two deflecting wads 3 in order for this fluid, and partially this vapor, to be able to pass through the liquid in order to condense it, while still keeping some of the supercooled liquid in the lower part.

[0063] In addition or alternatively, and as illustrated in FIG. 3, the last (upper) deflecting wall 3 may have a perforated structure (multiple holes) to allow the gas to pass through and to increase the contact surface area between the gas and the liquid.

[0064] This option may also be used advantageously in the event of filling the storage volume from the top in order to enlarge the areas of exchange between the entering (falling) liquid and the gas that is present. This makes it possible to avoid having to install a liquid distributor of the “injector” type over the length of the tank.

[0065] In addition or alternatively, the deflecting walls 3 may be made from a lightweight and flexible material (for example more lightweight than the rest of the tank) that retains its mechanical properties at low temperature in order to limit the additional mass of these deflecting walls 3 in the tank (cf. for example FR2966899A). This is because, for tanks used for transport, the mass of the tank limits the maximum amount of product that can be transported.

[0066] The tank according to the invention, by virtue of the deflecting walls at least partially submerged in the liquid phase, makes it possible to retain the stratification of the liquid while still keeping the liquid at the interface with the gaseous phase in equilibrium with the gaseous phase (typically at a pressure above atmospheric pressure). This makes it possible to keep supercooled layers of liquid in the lower part of the tank. This is particularly advantageous for a tank used for transport and in particular for transporting supercooled liquid.

[0067] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.