STORAGE DEVICE FOR A CRYOGENIC FLUID

Description

[0001] The invention relates to a cryogenic fluid storage device.

[0002] The invention relates more particularly to a cryogenic fluid storage device comprising a tank extending in a longitudinal direction and intended to contain liquefied gas in equilibrium with a gaseous phase, a device for pressurizing the tank, the pressurizing device comprising a pressurized gas generator and a pressurized gas injection ramp extending in the longitudinal direction in the upper part of the tank, the injection ramp comprising a plurality of gas outlet orifices spaced apart in the longitudinal direction.

[0003] In some applications, to withdraw liquid from a cryogenic tank, the tank must be pre-pressurized to provide sufficient pressure difference for transfer. In addition, this pressure must also be maintained during transfer.

[0004] In a known solution, an atmospheric heater is placed under the tank to enable pressurization by vaporizing part of the liquid contents of the storage. The vaporized and superheated gas is then reinjected into the gaseous atmosphere of the tank. See for example document FR1402554A.

[0005] However, the reinjected gas tends to heat the cryogenic liquid present in the tank, reducing the pressurizing power of the gaseous atmosphere and degrading the temperature of the liquid molecule (which we want to keep as cold as possible). These heat exchanges at the liquid / gas interface are all the more important as the reinjection speed is high. A non-optimized gas reinjection will therefore have the consequence of increasing this unwanted heat exchange during the liquid transfer phases. Known reinjection systems disturb the boundary layer at the liquid / gas interface.

[0006] US2015345708A1 describes another embodiment of a reservoir.

[0007] An aim of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

[0008] To this end, the device according to the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that at least one of: the spacing between the orifices, the diameter of the orifices, the number of orifices is different in the longitudinal direction between a first end of gas inlet into the ramp and a second opposite end of the ramp and configured to homogenize the flow rates leaving the orifices of the ramp in the longitudinal direction.

[0009] The resulting gas reinjection velocity field is more homogeneous than in the prior art and allows heat to be concentrated at the top of the gas dome, with minimal disturbance to the boundary layer at the liquid / gas interface. The stratification of the gas sky is improved.

[0010] Furthermore, embodiments of the invention may include one or more of the following features: at least some of the orifices have identical diameters and decreasing spacings from the first end to the second end of the ramp, at least some of the orifices have increasing diameters and constant spacings from the first end to the second end of the ramp, the second end of the ramp comprises a flow regulating member from among: a convergent, a divergent, an orifice, the device comprises several orifices located at at least one same longitudinal position of the ramp, at least two of the several orifices located at the same longitudinal position of the ramp are oriented in a distinct manner in the tank according to one of the following configurations: the orifices are located opposite each other on either side of the periphery of the ramp, the orifices are oriented towards the top and / or the bottom of the tank, the sum of the surfaces of the orifices is equal to the surface of the inlet section of the gas flow in the ramp,the manifold or the pipe to which the manifold is connected outside the tank comprises, near the first end, an elbow located above at least a portion of the remainder of the manifold extending towards the second end, the pressurized gas generator comprises a heater for the fluid taken from the tank.

[0011] The invention may also relate to any alternative device comprising any combination of the above or below characteristics within the scope of the claims. Other features and advantages will appear on reading the description below, made with reference to the figures in which: [ Fig. 1 ] represents a perspective view in transparency, schematic and partial, illustrating an example of structure and operation of a first possible example of embodiment of the invention, [ Fig. 2 ] schematically and partially represents a cross-section of a detail of the device according to a first embodiment, [ Fig. 3 ] schematically and partially represents a cross-section of a detail of the device according to a second embodiment, [ Fig. 4 ] schematically and partially represents a cross-section of a detail of the device according to a third embodiment, [ Fig. 5 ] represents a schematic and partial sectional and side view illustrating another exemplary embodiment of the structure and operation of the invention. The cryogenic fluid storage device 1 illustrated as an example comprises a tank 2, for example of generally cylindrical shape, extending in a longitudinal direction A which is preferably horizontal when the tank 2 is in the use configuration. The tank 2 is of the cryogenic type, that is to say configured to contain liquefied gas 3 (a liquid phase in the lower part surmounted by a gaseous phase in the upper part).

[0012] The device 1 further comprises a device 5, 6 for pressurizing the tank 2. This pressurizing device conventionally comprises a pressurized gas generator 5 fluidically connected to a pressurized gas injection ramp 6 extending in the longitudinal direction A in the upper part of the tank 2. That is to say that the injection ramp is located in the upper half of the tank, in particular adjacent to the upper end of the tank. The injection ramp is thus located in the gas phase of the tank. The pressurized gas generator 5 may comprise, for example, a heater for the fluid taken in liquid form from the tank 2. The generator is configured to supply the injection ramp 6 with pressurized gas.

[0013] For example, the injection ramp 6 is fixed by plates 9 at the level of the upper surface of the tank 2. For example, the ramp 6 is located at a distance from the highest part of the tank 2 of between 10 mm and 200 mm.

[0014] The injection ramp 6 is provided with a plurality of gas outlet orifices 7 distributed along the longitudinal direction A.

[0015] The spacing D1, D2,... between the orifices 7 and / or the diameter d0, d1, d2,... (or the section) and / or the number of orifices 7 varies according to the longitudinal direction A between a first end of gas inlet in the ramp 6 and a second opposite end of the ramp 6, so as to homogenize the flow rates leaving the orifices 7 of the ramp 6 according to the longitudinal direction A.

[0016] That is to say that the surfaces of the orifices opening into the tank vary according to the longitudinal direction A.

[0017] Ramp 6 preferably crosses the entire gaseous sky of tank 2 (over its entire length or the majority of its length).

[0018] For example, at least some of the orifices 7 have identical diameters (or sections) d0, d1, d2 and spacings D1, D2 decreasing from the first end towards the second end of the ramp.

[0019] Alternatively or cumulatively, at least some of the orifices 7 have increasing diameters d0, d1, d2, etc. and spacings D1, D2, etc. that are constant from the first end to the second end of the ramp. These increasing diameters or sections can also be obtained, for example, by varying the number of orifices 7.

[0020] For example, the sum of the areas of all the orifices 7 may be equal to the area of ​​the inlet section of the gas flow in the ramp 6.

[0021] The second end of the ramp 6 preferably comprises a flow regulating member 8 from among: a convergent, a divergent, an orifice. This regulating member 8 is configured to contribute to the control of the flow rate and the injection speed at the end of the ramp 6.

[0022] As schematized in [ Fig. 2 ], [ Fig. 3] et [Fig. 4 ], the ramp 6 may comprise groups of several orifices 7 at one or more longitudinal positions.

[0023] For example, orifices 7 of the same group or of two different groups can be oriented differently towards the interior of the tank 2.

[0024] For example, orifices 7 are located opposite each other on the periphery of the ramp 6 (jets oriented laterally on each side downwards in the tank 2) cf. [ Fig. 3 ] and / or towards the top of the tank (see [ Fig. 3 ]) and / or the orifices are oriented laterally substantially horizontally cf. [ Fig. 4 ].

[0025] The orientation of the orifices 7, giving the inclination to the gas jet, makes it possible to reduce the appearance of convective cells and / or reduce thermal exchanges at the wall of the tank 2.

[0026] The holes can be positioned symmetrically or not on the ramp 6.

[0027] As illustrated in [ Fig. 5 ], the ramp 6 may comprise, near the first end, an elbow 19 located above at least a portion of the remainder of the ramp 6 extending towards the second end.

[0028] This makes it possible to avoid liquid returning to the heater 5 if the ramp 6 is partially flooded with liquid (waves in the tank 2 or a steep slope during use, for example). This embodiment is not, however, limiting. Thus, this elbow 19 could be formed outside the tank 2, for example at the level of the portion of pipe which supplies the ramp 6 with gas.

[0029] The device allows the reduction of pressurization times in tank 2.

[0030] In addition, such an arrangement makes it possible to reduce the quantity of liquid used in the heater 5 (or equivalent) during transfers.

[0031] Heat transfers within Tank 2 are also reduced at the liquid / gas interface. There is also a potential reduction in the reheating of the liquid present in Tank 2 via stratification of the gas dome (due to homogenization and reduction of the reinjection velocity field).

Claims

1. Device for storing cryogenic fluid comprising a tank (2) extending in a longitudinal direction (A) and suitable for containing liquefied gas (3) in equilibrium with a gas phase, device (5, 6) for pressurizing the tank (2), the pressurization device comprising a pressurized gas generator (5) fluidly connected to a rail (6) for injecting the pressurized gas extending in the longitudinal direction (A) in the upper portion of the tank (2), the injection rail (6) comprising a plurality of gas outlet orifices (7) spaced apart in the longitudinal direction (A), at least one of the spacing (D1, D2) between the orifices (7), the diameter (d0, d1, d2) of the orifices (7) and the number of the orifices (7) being different in the longitudinal direction (A) between a first end through which the gas enters the rail (6) and an opposite second end of the rail (6) and configured to render the flow rates leaving the orifices (7) of the rail (6) uniform in the longitudinal direction (A), characterized in that the pressurized gas generator (5) comprises a heater for the fluid withdrawn from the tank, said generator (5) being configured to supply the injection rail (6) with pressurized gas.

2. Device according to Claim 1, characterized in that at least some of the orifices (7) have identical diameters (d0, d1, d2) and decreasing spacing (D1, D2) from the first end towards the second end of the rail (6).

3. Device according to Claim 1 or 2, characterized in that at least some of the orifices (7) have increasing diameters (d0, d1, d2) and constant spacing (D1, D2) from the first end towards the second end of the rail (6).

4. Device according to any one of Claims 1 to 3, characterized in that the second end of the rail (6) comprises one flow control member (8) selected from a convergent tube, a divergent tube, and an orifice.

5. Device according to any one of Claims 1 to 4, characterized in that it comprises a plurality of orifices (7) situated in at least one single longitudinal position on the rail (6).

6. Device according to Claim 5, characterized in that at least two of the plurality of orifices (7) situated in a single longitudinal position on the rail (6) are oriented differently in the tank in one of the following configurations: the orifices (7) are situated opposite each other on either side of the periphery of the rail (6), the orifices are oriented towards the top and / or towards the bottom of the tank.

7. Device according to any one of Claims 1 to 6, characterized in that the sum of the surface areas of the orifices (7) is equal to the surface area of the inlet area of the gas stream into the rail (6).

8. Device according to any one of Claims 1 to 7, characterized in that the rail (6) or the pipe to which the rail (6) is connected outside the tank comprises, near the first end, an elbow (19) situated above at least one portion of the rest of the rail (6) extending towards the second end.