EP3899273A1

EP3899273A1 - Pumping device, plant and method for supplying liquid hydrogen

Info

Publication number: EP3899273A1
Application number: EP19842379.0A
Authority: EP
Inventors: Simon CRISPEL; Anh Thao THIEU; Gaëtan COLEIRO; Fabien Durand
Original assignee: Air Liquide SA; LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Current assignee: Air Liquide SA; LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 2018-12-19
Filing date: 2019-12-03
Publication date: 2021-10-27
Also published as: KR20210105928A; FR3090756A1; CN113167257A; JP7451529B2; CN113167257B; FR3090756B1; WO2020128197A1; CA3121594A1; US20220074397A1; JP2022511486A

Abstract

The invention relates to a device for pumping liquid hydrogen comprising, arranged in series between an inlet (12) for fluid to be compressed and an outlet (13) for compressed fluid, a first compression member (2), preferably with a piston, forming a first compression stage and a second compression member (3) with a piston forming a second compression stage, characterised in that the first compression member (2) is suitable for and configured to compress the liquid hydrogen in a supercritical state and in that the second compression member (3) is suitable for and configured to compress the supercritical hydrogen supplied by the first compression member to an increased pressure and in particular to a pressure of between 200 and 1000 bar.

Description

DESCRIPTION

Title: Pumping device, installation and method for supplying liquid hydrogen

The invention relates to a pumping device as well as an installation and a method for supplying liquid hydrogen.

The invention relates more particularly to a device for pumping liquid hydrogen comprising, arranged in series between an inlet for fluid to be compressed and an outlet for compressed fluid, a first compression member, preferably with piston, forming a first compression stage and a second piston compression member forming a second compression stage.

A known solution for disposing of hydrogen gas at high pressure from a source of liquefied hydrogen consists in storing liquefied hydrogen then in transferring, evaporating and heating it and finally in compressing it with conventional compression at room temperature.

However, the energy cost (compression of a sparse compressible fluid) and investment of these devices is too high. An alternative solution consists in directly compressing the liquid hydrogen, considered then as an incompressible fluid.

Several technologies exist for pumping liquid hydrogen.

For hydrogen energy applications in particular, it is necessary to compress the liquid hydrogen at high pressures. At these high pressures (> 300bar) pumping becomes more complex due for example to the presence of gas at the suction of the pumps. This presence of gas may be due to thermal inputs and to the heat of compression which vaporize the liquid and create cavitation phenomena. The gas created, compressed at high pressure, heats the pump all the more. Another reason may be the rates of leakage through piston seal rings which increase at high pressure. These relatively “hot” fluid leaks are difficult to recover. The suction comprising gas thus becomes sparse and the pump undergoes a drop in flow and performance.

Known solutions which recirculate leaks at the inlet of the pump combine all the aforementioned drawbacks. The document US20070028628 describes a two-stage pump in which the high pressure leaks are reinjected into the liquid storage. This constitutes a considerable loss of vaporization (“boil-off”).

According to known solutions, the liquid hydrogen is pumped in two stages (two compression stages in series) cf. US4447195. According to certain solutions, the pump is immersed in a container filled with liquid hydrogen which allows optimal thermalization and a limitation of the cavitation problems of the pump. This however makes the maintenance of the pump more complex.

A pump for liquid hydrogen must be able to meet several constraints: a long required service life (due in particular to the difficulty of its maintenance in a non-industrial environment despite frequent shutdowns / restarting, very good thermal insulation to avoid vaporization gases ("boil-offs") which generate hydrogen gas which is difficult to recover and which contributes to the phenomenon of cavitation in the pump.

The known devices are not entirely satisfactory.

An object of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

To this end, the device according to the invention, furthermore in accordance with the generic definition given in the preamble above, is essentially characterized in that the first compression member is suitable and configured to compress the liquid hydrogen in a supercritical state, the second compression member being able and configured to compress supercritical hydrogen supplied by the first compression member at an increased pressure and in particular at a pressure between 200 and lOOObar.

Furthermore, embodiments of the invention may include one or more of the following characteristics:

the first compression member is suitable and configured to compress the liquid hydrogen to a pressure of between and 13 and 200 bar, in particular between 14 and 10 Obar,

the first compression member comprises at least one assembly comprising a piston movable in translation in a jacket, the second compression member comprising at least one assembly comprising a separate piston disposed in a separate jacket, the pistons of the first and second compression members being moved in their respective sleeves in alternating movements at determined respective displacement speeds, the displacement speed of the at least one piston of the first compression member being less than the displacement speed of the at least one piston of the second compression member,

the speed of movement of the at least one piston of the first compression stage 2 is between 0.02 m / s and 0.5 m / s and in particular between 0.02 m / s and 0.2 m / s,

the speed of movement of the at least one piston of the second compression stage is for example between 0.02 m / s and lm / s,

the at least one piston of the first compression member and / or the at least one piston of the second compression member is moved via a drive mechanism with linear actuator ensuring axial guidance of the piston in its jacket, in particular a screw type mechanism and planetary rollers and powered by electric motor, the first compression member and / or the second compression member is thermally isolated under vacuum, the first compression member and / or the second compression member comprises a heat shield which is thermalized by a cooling fluid,

the device comprises a thermalization circuit comprising a first upstream end intended to be connected to a source of liquefied gas and in particular a source of liquid hydrogen intended to be compressed by the pumping device and at least one downstream end ensuring a heat exchange between liquefied gas and heat shield,

the thermalization circuit comprises a portion connecting the thermal screen to the compression chamber of the compression member and configured to transfer at least a portion of the liquefied gas having thermally exchanged with the thermal screen in the compression chamber of the compression member, that is to say that the compression member compresses liquefied gas which has been used to cool its heat shield,

the device comprises a thermal fluid return circuit comprising one end connected to the thermal screen and one end intended to be connected to a source of liquefied gas and / or to a recovery zone for evacuating at least part of the liquefied gas heated having served to cool the heat shield, the speed of movement of the piston of the first compression member is between 0.02 and 0.05 m per second, the speed of movement of the piston of the second compression member is between 0, 02 and lm / s,

the first compression member and / or the second compression member comprises a circuit for collecting the vaporized hydrogen therein, said circuit comprising an evacuation outlet to a recovery zone,

the circuit for recovering leaks of fluid passing through the piston or pistons directs at least part of said leaks from the first compression stage towards the source,

the circuit for recovering leaks of fluid passing through the piston or pistons directs at least a portion of said leaks from the second compression stage to the thermalization circuit and in particular to the thermal screen with a view to cooling it and then, if necessary, its reintroduction into the second compression stage for re-compression,

the first compression member is disposed in an envelope forming a heat shield which is thermalised by a cooling fluid, the circuit of fluid to be compressed which transfers the fluid from the source to the first compression stage passing through the envelope of the first compression stage, said envelope of the first compression stage forming a supply chamber for the at least one piston of the first compression stage and a heat shield of the first compression stage.

The invention also relates to an installation for supplying pressurized liquid hydrogen comprising a pumping device according to any one of the characteristics above or below, the installation comprising a source of liquefied hydrogen and a transfer circuit comprising a line connecting the source to the inlet of the pumping device capable and configured to supply liquid hydrogen to the pumping device for its compression and delivery at the outlet.

According to other possible particularities: the installation comprises at least one return pipe having an upstream end connected to the pumping device and a downstream end connected to the source and suitable and configured to evacuate vaporized gas within the pumping device towards the source,

the at least one return line comprises at least one of: a manual or controlled valve, a pressure relief valve.

The invention also relates to a method for supplying liquid hydrogen under pressure using a device according to any one of the characteristics above or below or an installation according to any of the characteristics above or below, the method comprising a step of supplying liquid hydrogen to the inlet of the pumping device, a step of compressing this liquid hydrogen in the first compression member at a pressure between 14 and 100 bar and at a temperature between 20 and 40K, then an additional compression step, in the second compression member, of the hydrogen leaving the first compression member up to a pressure between 50 and 100 bar and at a temperature between and 40 and 150K.

According to other possible particularities:

The invention may also relate to any alternative device or method comprising any combination of the above or below features within the scope of the claims.

Other particularities and advantages will appear on reading the description below, made with reference to the figures in which:

[Fig. 1] represents a schematic and partial view illustrating an example of structure and operation of a pumping device according to a possible embodiment of the invention, [Fig. 2] represents a schematic and partial view illustrating an example of structure and operation of an installation according to a possible example of embodiment of the invention,

[Fig. 3] shows a schematic and partial view illustrating a detail of an example of the structure and operation of a drive member which can be used according to the invention.

The liquid hydrogen pumping device 1 shown in [Fig. 1] comprises, arranged in series between an inlet 12 for fluid to be compressed and an outlet 13 for compressed fluid, a first compression member 2 and a second compression member 3.

The first compression member 2 is preferably of the piston type (s) and forms a first compression stage for the fluid admitted by the inlet 12.

As an alternative to piston compression, it is possible to envisage a technology of the gear or lobe ("roots"), centrifugal or any other appropriate technology type.

The second compression member 3 is also preferably of the piston type (s) and forms a second stage of compression of the fluid towards the outlet 13.

The two compression members 2, 3 can in particular be housed or not in the same casing or case (cf. [Fig. 2]).

According to an advantageous feature, the first compression member 2 is able and configured to compress liquid hydrogen in or towards a supercritical state.

Preferably the first compression member 2 receives liquid hydrogen in a saturated state, for example a pressure between 0 and 10Obarg and a temperature between 20 and 32K.

That is to say that the first compression member 2 is configured to compress liquid hydrogen to a supercritical state (beyond the following conditions: Pc; = 12.98 bar, T _C = 33K). In this state, the fluid can no longer coexist in two phases (liquid and gas).

The second compression member 3 is itself suitable and configured to compress the supercritical hydrogen supplied by the first compression member at an increased pressure and in particular at a pressure between 200 and 100 bar.

Thus, at the input of the first compression stage 2, the fluid may have a pressure between 0 and 10 Obarg and a temperature between 20 and 32 K for example.

At the outlet of the first compression stage 2, the fluid may have a pressure between 13 and 150 bar (in particular between 14 and 100 bar) and a temperature between 20 and 50 K for example.

At the outlet of the second compression stage 3 the fluid may have a pressure between 50 and 1000 bar and a temperature between 40 and 150 K for example.

That is to say that the second compression member 3 performs the main work of compressing the fluid.

Thus, the first compression member 2 can be adapted and configured to compress liquid hydrogen to a pressure between and 5 and 200 bar and preferably between 13 and 150 barg, in particular between 14 and 100 bar.

This architecture makes it possible to avoid compressing in the second compression member 3 a fluid whose properties, in particular the density, are very sensitive and poorly controlled. This makes it possible to limit or manage the cavitation phenomena (boil-off) in dedicated equipment provided for this purpose (first compression member 2). Indeed, by pumping liquid, even a very slight deviation from saturation creates gas in the liquid and strongly modifies the density of the pumped fluid. The supercritical fluid does not change phase and its density varies gradually.

Indeed, by deviating even slightly from saturation, the density of the fluid is thus very strongly modified, all the more so when the operating pressure is low. Thus, high pressure compression is concentrated on the second compression stage.

The supercritical fluid produced by the first compression stage is thus transmitted to the second compression stage (which is preferably independent of the first compression stage). This second compression stage can thus be designed to produce the main compression work up to the required final pressure level.

Preferably, the supply of fluid from the first compression stage to the second compression stage takes place through the outer casing 16 which houses the piston or pistons of the second compression stage. Thus, the casing 16 around the piston or pistons of the second compression stage 3 plays both the role of supply chamber for the compression chamber of said pistons 6 and of thermal screen.

The intermediate operating conditions, the active pressure regulation between the two compression stages (via for example the compression speed of the first stage) and the thermo-hydraulic design can be determined so as to generate little or no loss (boil-off ) (and low pressure return) at the intake of the second pressure stage.

The proposed architecture makes it possible to adjust the speed of movement of the first compression member (piston (s) 4) to control the thermodynamic conditions of the fluid at the inlet of the second compression member (that is to say at the inlet of the piston (s) 6 concerned).

As illustrated in [Fig. 2], a unidirectional valve 32 can be provided between the two compression stages.

The relatively different speeds of the two compression stages and the piston drive / control mode facilitate pressure regulation.

The first compression member 2 is preferably configured to compress relatively slowly (for example at a displacement speed of the piston of 2 to 5 cm / s, and a frequency of the order of 5 strokes / minute). This will make it possible to bring the fluid into a supercritical state by limiting for example the irreversibilities, thermal inputs, effects of cavitations, and the wear of the components. The physical properties of the fluid (viscosity, density) are then better controlled and facilitate the production and operation of the second compression stage (dimensions, materials) by ensuring sealing and thermalization.

As illustrated in [Fig. 1], the first compression member 2 may comprise a piston 4 movable in translation in a jacket 5. The piston 4 and the jacket 5 conventionally define a compression chamber.

Similarly, the second compression member 3 may include a separate piston 6 disposed in a separate jacket 7. The pistons 4, 6 of the first and second compression members are moved in their respective sleeves 5, 7 according to reciprocating movements at determined respective displacement speeds. Advantageously, the speed of movement of the piston 5 of the first compression member 2 is preferably less than the speed of movement of the piston 7 of the second compression member 3.

As shown schematically in [Fig. 1], the piston 4 of the first compression member 2 and / or the piston 6 of the second compression member 3 can be moved via a respective drive mechanism 8 of the planetary screw and roller type. These mechanisms are preferably actuated by separate respective motors, in particular electric motors.

Of course a common engine could be envisaged

Preferably, the displacement speeds of the pistons 4, 6 of the two compression stages are distinct and mechanically independent. That is to say that there is no mechanical coupling between the pistons 4, 6 of the two compression stages which would mechanically condition the speed of the pistons of a compression stage as a function of the displacement speed of the pistons of the other compression stage.

The speed of the piston (s) 4 of the first compression stage 2 can be calculated in real time to optimize the stability of the thermodynamic conditions at the level of the second compression stage 2. Thus, the displacement speeds of the pistons of the two compression stages can be thermodynamically interdependent but mechanically controlled independently.

The [Fig. 3] schematically represents an example of a drive mechanism 8 of the screw 25 and planetary roller 26 type. For the sake of simplification, the nonlimiting example of the complete mechanism illustrated (nut 27, ring 28 guide 29, ring 30, etc.) is not described in detail.

This type of drive allows optimal control, especially in position (very reduced clearances), high loads and high reliability of the compression members. This allows flexibility and adaptability making it possible to manage (if necessary in real time) separate displacement speeds for each compression stage.

The first compression stage can therefore include or may consist of at least one piston 4 -shirt 5 assembly which is thermalized (that is to say kept cold at a temperature for example between 20 and 30K). The at least one piston 4 and jacket 5 assembly is preferably housed in a sealed envelope 15. This thermalization can be carried out at the level of the casing 15 containing the cryogenic intake fluid. This casing 15 can be isolated under vacuum with an external wall. The envelope 15 houses and thermally insulates the at least one piston assembly 4 - sleeve 5. Of course, each piston assembly 4 - sleeve 5 could be housed in a respective respective envelope.

This envelope 15 can form a heat shield which is cooled by an internal or external cooling fluid at the device, for example liquid hydrogen supplied by the source 10 of fluid intended to be compressed.

Thus the casing 15 can be a volume filled with cooling fluid and / or a mass cooled by the fluid.

The device may include a thermalization circuit 9 comprising a first upstream end (pipe 11) connected to a source 10 of liquefied gas and in particular a source of liquid hydrogen intended to be compressed by the pumping device and at least one end ensuring a heat exchange between the liquefied gas and the casing 15.

Source 10 stores, for example, liquid hydrogen at a pressure between 1 and 10 barg.

The thermalization circuit 9 may comprise a portion 17 connecting the casing 15 to the compression chamber of the compression member 2. This portion 17 is configured to transfer at least part of the liquefied gas which has thermally exchanged with the casing 15 in the compression chamber of the compression member 2. That is to say that the compression member 2 preferably compresses at least part of the liquefied gas which has been used to cool its envelope 15 forming a heat shield.

Thus, the hydrogen liquid can pass through the envelope 15 forming a heat shield before being admitted into the compression chamber. The piston 4 / jacket 5 assembly is therefore bathed and cooled in the envelope 15 forming a heat shield. The evaporated liquid, very little therefore, can be recirculated in the source 10 via a line 14.

The fluid compressed by the first compression member is transferred 19 into the compression chamber of the second compression member 3. Before entering the compression chamber of the second compression member 3, as before, the fluid compressed by the first compression member can be used to cool the envelope 16 forming a heat shield 16 for the second compression stage. Preferably, the supercritical fluid compressed by the first compression member 2 is transferred through and into the envelope 16 (which is preferably a volume and not only a cooled mass). This fluid passes through the volume of the screen 16 forming a heat shield and cools the piston 6-jacket 7 assembly before entering the compression chamber of the second compression member. The leakage of piston (s) can be recirculated in the volume of the casing 16 to be then compressed again.

The fluid in the envelope 16 forming a thermal screen being supercritical, it is possible to configure the thermal inputs, the compression heat and the leaks without cavitation, therefore without much degradation of the pump flow rate.

The second compression member 3 may in particular have an insulation structure similar to that of the first compression member 2. That is to say that the second compression stage can therefore comprise or may consist of at least one piston 6 -shirt 7 assembly which is thermalized (that is to say kept cold at a temperature between 30 and 50K ). This thermalization can comprise an envelope 16 containing the cryogenic intake fluid, this envelope 16 can be isolated under vacuum with an outer wall. This envelope 16 can form a heat shield which is further cooled by a cooling fluid, for example liquid hydrogen supplied by the source 10 of fluid (fluid coming directly from the source 10 or the fluid having already served in the first stage compression and / or by an external source of cooling fluid or other type of cold supply).

The device 1 preferably comprises a circuit 14, 21, 22 for returning the thermalization fluid comprising an end connected to the casing 15 and an end intended for a recovery zone and in particular the source 10 of liquefied gas. This allows to evacuate and if necessary to recover at least one part of the heated liquefied gas used to cool the casing 15 forming a heat shield.

Preferably, the circulation of the fluid for thermalization is obtained by an effect of the thermosyphon type. That is to say, the thermalization evaporates liquefied fluid which decreases its density and causes the return of cold gas to the source 10, the return line being configured to allow and optimize this operation.

In this way, the sealing defects reduced to the maximum by this dedicated operation of the first compression stage 2 (lower power, lower pressure, lower speed, and perfectly thermalized) can however be taken up and returned to the source tank 10.

As illustrated in [Fig. 2], it is also possible to provide one or more vapor vapor recovery pipes at the second compression member 3.

For example, one or two pipes 21, 22 can be provided to return the heated fluid to the source 10 directly 22 or via a similar pipe 14 for the first compression member 2. The line (s) 21, 22 may comprise at least one valve 23 and / or a valve 24 forming a valve opening at a determined pressure level.

In the operating phase (that is to say in the compression phase), the second compression member 3 is cooled by the incoming fluid. Leaks and thermal inputs are therefore absorbed by the fluid before being admitted to the pumping member. In the standby phase (no compression), the second pumping member 3 could be kept cold by the circuit of 21-22 via a circulation of fluid. This operation makes it possible to minimize gas losses from high pressure compression. Preferably the two compression members 2, 3 are configured to operate and be able to be controlled independently. That is to say that the speed of movement of each piston 4, 6 can be controlled independently of the speed of movement of the other piston (the two compression stages are mechanically independent). Thus, for example, the displacement speeds of the two pistons 4, 6 are not directly controlled or mechanically dependent on each other. It is thus possible to modify the speed of movement of the piston (s) of one compression stage without this automatically modifying the speed of movement of the piston (s) of the other compression stage. The displacement speeds of one or both pistons can be fixed or modified to respective values which are not directly correlated (with the only reservation that the displacement speed of the piston of the first compression member 5 is preferably less than the speed of movement of the piston of the second compression member). Likewise, the movements of the two pistons of the two compression stages can be non-synchronized.

The two compression members 2, 3 can therefore be regulated in speed and / or in position and / or in displacement travel to respectively control the intermediate thermodynamic conditions, in particular the pressure (at the outlet of the first compression stage 2) and the output pressure of the second compression stage. This intermediate pressure can be controlled at a value between 13 and 150 bar for example.

The difference in speed of movement of the pistons 4, 6 between the two compression stages can be chosen large enough to stabilize the pressure between the two compression stages. If necessary, a buffer storage can be provided between the two compression stages to increase this pressure stability.

The losses of the second compression stage 3 are limited by the recirculation of fluid at the intake, while the differences in piston speeds make it possible to optimize the service life and the time between two maintenance operations while achieving the required performance. This contributes to limiting or canceling losses at the second compression stage 3. Consequently, a vapor recovery circuit can possibly be omitted for the second compression stage.

The first stage is preferably particularly thermally optimized (vacuum chamber and pump thermalised by the intake fluid) to limit thermal inputs. Evaporation of the hydrogen, the residual evaporated gas is preferably returned to source storage 10.

In this way, the second compression stage can be in thermal equilibrium and generates little or no loss of gas. This second compression stage 3 can in particular be thermally balanced by design. That is to say that the compression and friction energy can be removed to generate a stable temperature of the components within the second compression member 3.

In the event of non-use (between two uses of the pumping device), the first compression member 2 can be actuated intermittently to keep the device cold and in particular the second compression member 3. As a variant or in combination, cooling may be provided (heat exchanger (s) with a loop for cooling the fluid from / to the source 10 in thermosyphon via the pipes 21-21 for example).

The pumping device 1 (and / or the installation) may comprise an electronic data storage and processing member comprising for example a microprocessor for controlling all or part of the components (valve (s) and / or motor and / or motor ...).

Thus, according to the invention, the pumping device can comprise a two-stage pump (two compression stages) of which one of the stages (first stage 2) compresses subcritical fluid while the second stage 3 compresses supercritical fluid . A third high compression stage pressure may possibly be provided downstream. The device can advantageously control the speed or speeds of displacement of the compression pistons 4, 6 making it possible to extend the life of the pistons (and of the seals).

In the example described above, the first compression member 2 and the second compression member 3 each have a single movable piston in its jacket (compression chamber). Of course, the first 2 and / or the second 3 compression stage may comprise more than one piston / liner assembly and in particular two movable pistons each in a respective liner (compression chamber). So the first

2 compression stage could comprise a single piston / liner assembly (so-called single head stage) while the second stage 3 could comprise two movable pistons in respectively two compression chambers (compression stage known as “twin heads”).

In the case of multiple piston / liner assemblies with one compression stage, these piston / liner assemblies are arranged in parallel.

The invention has been described in an example with two members 2,

3 compression to reach the target pressure (lOOObar for example). Of course it can be envisaged to provide an architecture in which at least a third intermediate compression stage is used between the first stage 2 (which compresses for example up to a pressure of 200bar) and the last compression stage 3 (which compresses up to the target pressure, in particular lOOObar).

In certain configurations of use, the speed of movement of the at least one piston 5 of the first compression stage can be greater than the speed of movement of the at least one piston 6 of the second compression stage.

This can be used for example when the pump is in a standby mode (second piston stopped and the first piston has a very slow movement). In another configuration, if the first compression stage has one or more pistons undersized with respect to the piston (s) of the second compression stage, in this case the piston (s) of the first compression stage compression can move at a higher speed than the displacement of the piston (s) of the second compression stage.

For the sake of simplification, in the examples shown, each compression stage comprises a single piston 4, 6. Of course, each compression stage can comprise one or more piston-liner assemblies. For example, the first and second compression stages may each comprise two piston-liner assemblies in parallel (that is to say two pistons per compression stage). Each compression stage is preferably powered by a separate engine. That is, there are two motors, each of the motors moving the pistons of a respective compression stage.

Claims

1. A liquid hydrogen pumping device comprising, arranged in series between an inlet (12) for fluid to be compressed and an outlet (13) for compressed fluid, a first compression member (2), preferably with piston (s) , forming a first compression stage and a second piston compression member (3) forming a second compression stage, the first compression member (2) being able and configured to compress liquid hydrogen in a supercritical state , the second compression member (3) being able and configured to compress the supercritical hydrogen supplied by the first compression member at an increased pressure and in particular at a pressure between 200 and 100 bar, characterized in that the first member (2 ) of compression comprises at least one assembly comprising a piston (4) movable in translation in a jacket (5), the second compression member (3) comprising at least one assembly comprising a piston (6) distinct disposed in a jacket (7 ) distinct, the pistons (4, 6) of the first and second compression members being moved in their respective sleeves (5, 7) by respective mechanisms according to reciprocating movements at respective determined independent displacement speeds, that is to say say that the pistons (4, 6) of the first and second compression members are moved at respective mechanically independent travel speeds.

2. Device according to claim 1, characterized in that it is configured to maintain, in operating configuration, the speed of movement of the at least one piston (5) of the first compression member (2) at a value less than the speed of movement of the at least one piston (7) of the second compression member (3).

3. Device according to claim 1 or 2, characterized in that the first compression member (2) is adapted and configured to compress the liquid hydrogen at a pressure between and 13 and 200 bar, in particular between 14 and 10 Obar.

4. Device according to any one of claims 1 to 3, characterized in that the speed of movement of the at least one piston (4) of the first stage 2 of compression is between 0.02m / s and 0.5 m / s and the speed of movement of the at least one piston of the second stage of compression is less than 2m / s and in particular less than lm / s.

5. Device according to any one of the claims

1 to 4, characterized in that the at least one piston (4) of the first compression member (2) and / or the at least one piston (6) of the second compression member (3) is moved via a mechanism (8 ) drive with linear actuator ensuring axial guidance of the piston in its jacket, in particular a mechanism of the planetary screw and roller type and actuated by an electric motor (20).

6. Device according to any one of claims 1 to

5, characterized in that the first compression member (2) and / or the second compression member (3) is thermally insulated under vacuum.

7. Device according to any one of claims 1 to

6, characterized in that the first compression member (2) and / or the second compression member (3) is arranged in an envelope (15, 16) forming a heat shield which is thermalized by a cooling fluid.

8. Device according to claim 7, characterized in that the second compression member (3) is disposed in an envelope (16) forming a heat shield which is thermalized by a cooling fluid, the circuit of fluid to be compressed which transfers the fluid from the first compression stage (2) to the second compression stage (3) passing through the casing (16) of the second compression stage, said casing (16) of the second compression stage forming a supply chamber for the at least one piston (6) of the second compression stage and a heat shield of the second compression stage.

9. Device according to claim 7 or 8 characterized in that it comprises a thermalization circuit (9) comprising a first upstream end intended to be connected to a source of liquefied gas and in particular a source (10) of liquid hydrogen intended to be compressed by the pumping device and at least one downstream end ensuring a heat exchange between the liquefied gas and the casing (15, 16).

10. Device according to claim 9, characterized in that the thermalization circuit (9) comprises a portion (17, 18) connecting the envelope (15, 16) to the chamber of compression of the compression member (2, 3) and configured to transfer at least a portion of the liquefied gas having heat exchanged with the envelope (15, 16) in the compression chamber of the compression member (2, 3), that is to say that the compression member (2, 3) compresses liquefied gas which has been used to cool its envelope forming a heat shield.

11. Device according to claim 9 or 10, characterized in that it comprises a circuit (14, 21, 22) for return of thermalization fluid comprising an end connected to the envelope (15, 16) and an end intended for be connected to a source of liquefied gas and / or to a recovery zone to evacuate at least part of the reheated liquefied gas used to cool the casing (15, 16).

12. Device according to any one of claims

7 to 11, characterized in that it comprises a circuit

(33) for recovering fluid leaks passing through the piston (s) to a recovery volume (10) and / or the thermalization circuit.

13. Installation for supplying pressurized liquid hydrogen comprising a pumping device (1) according to any one of the preceding claims, the installation comprising a source (10) of liquefied hydrogen and a circuit (9, 17, 19 , 18) transfer comprising a line (11) connecting the source (10) to the inlet (12) of the pumping device (1) able and configured to supply liquid hydrogen to the pumping device (1) in view compression and delivery at the outlet (13).

14. Installation according to claim 13, characterized in that it comprises at least one return pipe (14, 21, 22) having an upstream end connected to the pumping device (1) and a downstream end connected to the source (10 ) and adapted and configured to evacuate vaporized gas within the pumping device (1) towards the source (10).

15. A method of supplying liquid hydrogen under pressure using a device according to any one of claims 1 to 12 or an installation according to any one of claims 13 or 14, the method comprising a step of supplying liquid hydrogen to the inlet (12) of the pumping device (1), a step of compressing this liquid hydrogen in the first compression member (2) at a pressure between 14 and 100 bar and at a temperature between 20 and 40K, then an additional compression step, in the second compression member (3), of the hydrogen leaving the first compression member (2) to a pressure between 50 and 1000bar and at a temperature between and 40 and 150K.