FACILITY AND METHOD FOR THE LIQUEFACTION OF HYDROGEN

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a § 371 of International PCT Application PCT/EP2023/066540, filed Jun. 20, 2023, which claims the benefit of FR2207466, filed Jul. 21, 2022, both of which are herein incorporated by reference in their entireties.

FIELD OF THE INVENTION

The invention concerns a facility as well as a method for the liquefaction of hydrogen.

BACKGROUND OF THE INVENTION

The evaporation (boil-off) in systems for filling of trucks and tanks in hydrogen liquefaction factories can give rise to losses which can be as much as 15% of the production.

It will be appreciated that these losses by evaporation can be recuperated, reheated, recompressed after storage, and reinjected into the liquefier. This requires a system for recirculation of the losses and an adequate size of the liquefier.

Another solution for minimizing the production of these vaporization gases consists of undercooling the liquid hydrogen produced.

The known solutions for recuperating these vaporization gases can have disadvantages as described hereinafter.

Thus, part of the depressurization of the truck need not be carried out towards the liquid store of the facility by balancing of pressure, since the pressure of the truck can become lower than that of the store. The hydrogen is thus lost or sent to a recuperation system as described above.

During the filling of the trucks, it can happen that cold vapor can no longer return to the liquid store of the facility as a result of a lack of driving pressure. These vapors are liable to be lost.

In general, the cold which is present in the stores does not make it possible to compensate for all the additional heat generated by the operations of filling of the trucks. This generates an increase in the pressure of the stores, and a loss of hydrogen.

The return temperature of the vapors of the trucks to be filled can be too high to be liquefied directly.

The depressurization is generally intermittent. The lines or ducts heat up between two operations of filling of the trucks, and the returns of gas to the liquefier are correspondingly hotter and more difficult to liquefy.

When the liquid store of the facility is relatively small, the pressure of the store drops during operations of filling of the trucks. This makes it necessary to use a device for pressurization of the liquid store, and thus to vaporize liquid hydrogen which will need to be reliquefied later.

An objective of the present invention is to eliminate some or all of the disadvantages of the prior art indicated above.

SUMMARY OF THE INVENTION

In certain embodiments, the invention concerns a facility for the liquefaction of hydrogen comprising a hydrogen circuit with an upstream end which is designed to be connected to a source of gaseous hydrogen, and a downstream end which is connected to at least one liquefied hydrogen cryogenic store of the facility, the cryogenic store being provided with a drawing-off duct which is configured to permit the supply of liquefied hydrogen to at least one tank to be filled, in particular a mobile tank, the facility comprising a cold box which houses a series of heat exchangers in thermal exchange with the hydrogen circuit, the facility comprising a device for cooling in thermal exchange with at least part of the series of heat exchangers which is configured to cool the hydrogen circuit, said cooling device comprising a cryogenic refrigerator with a cycle for refrigeration of a cycle gas in a work circuit, the cycle gas comprising at least one out of: hydrogen, helium, the work circuit of the refrigerator comprising a unit for compression of the cycle gas, a unit for cooling of the cycle gas, a unit for expansion of the cycle gas, and a unit for heating of the cycle gas, the facility comprising a duct for recuperation of vaporization gas provided with at least one upstream end which is connected to the store and/or is designed to be connected to a tank to be filled, and a downstream end which is connected to the hydrogen circuit.

In an effort to overcome the deficiencies of the prior art discussed, supra, the facility according to certain embodiments of the invention, which moreover is in conformity with the generic definition thereof given in the above preamble, is configured such that the downstream end of the recuperation duct is connected to the interior of the cold box, and, before its connection to the hydrogen circuit, it comprises a portion in thermal exchange with at least one exchanger of the series of heat exchangers.

This permits the return of the vaporization gas into one of the exchangers of the cold box of the liquefier at a temperature which is compatible with this exchanger.

Since the power which is necessary for the liquefaction of the hydrogen is directly associated with the pressure of the gaseous hydrogen, this configuration makes it possible to liquefy gas at a relatively high pressure.

This configuration makes it possible to conserve or maintain the highest possible pressure in the heat exchanger which cools this recuperated vaporization gas (at the moment of liquefaction), while limiting the increase in pressure necessary in cases when the pressure is low in the stores or the trucks supplying this vaporization gas.

This architecture has a low impact on the capacity of the liquefier.

In addition, embodiments of the invention can comprise one or more of the following characteristics:

• • the downstream end of the recuperation duct comprises a unit for expansion of the flow of vaporization gas, which unit is preferably situated between the portion in thermal exchange with the at least one exchanger of the series of heat exchangers and the connection to the hydrogen circuit;
  • the series of heat exchangers comprises a plurality of heat exchangers positioned in series between the upstream end and the downstream end of the hydrogen circuit, the connection of the downstream end of the recuperation duct to the hydrogen circuit being situated downstream from a first passage of the hydrogen circuit in the final heat exchanger in series;
  • the first passage of the hydrogen circuit in the final heat exchanger in series comprises a section for catalysis of the hydrogen which is configured to carry out the conversion of at least part of the Ortho hydrogen into Para hydrogen;
  • downstream from the connection, the hydrogen circuit provides a second passage in the final heat exchanger;
  • the second passage in the final heat exchanger does not comprise a section for catalysis of the Ortho hydrogen into Para hydrogen;
  • downstream from the second passage in the final heat exchanger, the hydrogen circuit comprises a unit for expansion of the flow of hydrogen, said expansion unit comprising at least one out of: an expansion valve, a turbine;
  • upstream from the connection to the hydrogen circuit, the downstream end of the recuperation duct comprises a catalysis section which is configured to carry out the conversion of at least part of the Para hydrogen into Ortho hydrogen;
  • the downstream end of the recuperation duct comprises a bypass portion and a series of valves which are configured to assure or not assure the passage of the flow of vaporization gas in said catalysis section;
  • the downstream end of the recuperation duct comprises a bypass portion and a series of valves which are configured to assure or not assure the passage of the flow of vaporization gas in said catalysis section;
  • the recuperation duct comprises a compression unit such as a compressor of a cryogenic type;
  • the recuperation duct comprises a first upstream end which is connected to the store, and a second upstream end which is designed to be connected to a mobile tank;
  • the first and second upstream ends of the recuperation duct are connected to the downstream end of the recuperation duct respectively via two distinct branches of ducts, and the compression unit is situated in the duct branch of the second upstream end of the recuperation duct.

The invention also concerns a method for the liquefaction of hydrogen using a facility according to any one of the characteristics above or below, comprising a step of recuperation of vaporization gas via the recuperation duct, a step of cooling of this vaporization gas recuperated in the cold box, a step of expansion of this vaporization gas in the cold box, and a step of mixing of this expanded vaporization gas with the flow of hydrogen to be cooled.

According to other possible particular characteristics:

• • the method comprises at least one out of: a step of expansion of the mixture of the vaporization gas and the flow of hydrogen to be cooled, a step of expansion of the mixture of the vaporization gas and of the flow of hydrogen to be cooled.

The invention can also concern any alternative method or device comprising any combination of the characteristics above or below within the context of the claims.

Other particular characteristics and advantages will become apparent from reading the following description, provided with reference to the figures in which:

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, claims, and accompanying drawings. It is to be noted, however, that the drawings illustrate only several embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it can admit to other equally effective embodiments.

The invention will be better understood by reading the following description provided purely by way of example with reference to the appended drawings in which:

FIG. 1 is a schematic partial view illustrating a first example of a structure and operation of a facility in a first configuration;

FIG. 2 is a schematic partial view illustrating a detail of the structure and the operation of such a facility according to a first possible embodiment;

FIG. 3 is a schematic partial view illustrating this first example of a facility in a second configuration;

FIG. 4 is a schematic partial view illustrating this first example of a facility in a third configuration;

FIG. 5 is a schematic partial view illustrating this first example of a facility in a fourth configuration;

FIG. 6 is a schematic partial view illustrating this first example of a facility in a fifth configuration;

FIG. 7 is a schematic partial view illustrating this first example of a facility in a sixth configuration;

FIG. 8 is a schematic partial view illustrating this first example of a facility in a seventh configuration;

FIG. 9 is a schematic partial view illustrating the structure and the operation of a second embodiment in a first configuration;

FIG. 10 is a schematic partial view illustrating this second example of a facility in a second configuration;

FIG. 11 is a schematic partial view illustrating this second example of a facility in a third configuration;

FIG. 12 is a schematic partial view illustrating this second example of a facility in a fourth configuration;

FIG. 13 is a schematic partial view illustrating a detail of the structure and the operation of another possible embodiment of the facility.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the figures, the same references relate to the same elements.

In this detailed description, the following embodiments are examples. Although the description refers to one or more embodiments, this does not mean that the characteristics apply only to a single embodiment. Simple characteristics of different embodiments can also be combined and/or interchanged in order to provide other embodiments.

The hydrogen liquefaction facility 1 illustrated in FIG. 1 comprises a hydrogen circuit 2 to be cooled/liquefied. This hydrogen circuit 2 has an upstream end 21 which is designed to be connected to a source 23 of gaseous hydrogen, and a downstream end 22 which is connected to at least one cryogenic store 8 for liquefied hydrogen produced by the facility 1.

The source 23 of gaseous hydrogen can comprise an electrolyzer, a gaseous hydrogen network, and/or any other device for production of hydrogen.

The cryogenic store 8 comprises for example an insulated cryogenic tank under vacuum, and is provided with at least one drawing-off duct 11 configured to permit the supply of liquefied hydrogen to at least one tank 19 to be filled (for example a cryogenic tank 19 transported by a truck).

The facility 1 comprises a cold box 18, i.e. an insulated, preferably sealed cryogenic enclosure which houses at least part of the cryogenic liquefaction units forming a liquefier 31.

The cold box 18 houses in particular a series of heat exchangers 3, 4, 5, 6 in thermal exchange, and a cold part of the hydrogen circuit 2 in thermal exchange with these heat exchangers 3, 4, 5, 6.

The facility 1 also comprises a cooling device in thermal exchange with at least part of the series of heat exchangers 3, 4, which device is configured to produce a cold power used to cool the hydrogen circuit 2.

This cooling device preferably comprises a cryogenic refrigerator 7 with a cycle for refrigeration of a cycle gas in a work circuit. In other words, the work circuit subjects the cycle gas to a thermodynamic cycle which brings this cycle gas to a cold end at a cryogenic temperature, in order to provide a cold cooling power.

The cycle gas comprises for example at least one out of: hydrogen, helium. The work circuit of the refrigerator 7 comprises a unit 9 for compression of the cycle gas (one or more compressors in series and/or in parallel), a unit 3, 4 for cooling of the cycle gas, a unit 10 for expansion of the cycle gas (turbine(s) and/or expansion valve(s)) and a unit 6, 5, 4, 3 for heating of the cycle gas. The units for cooling and heating of the gas can comprise heat exchangers, and in particular countercurrent heat exchangers which assure simultaneously heating and cooling of the cycle gas in the work circuit.

The facility 1 also comprises at least one duct 12 for recuperation of vaporization gas. This recuperation duct 12 is provided with at least one upstream end which is connected to the store 8, and/or is designed to be connected to a tank 19 to be filled, and a downstream end which is connected to the hydrogen circuit 2, in order to recuperate the vaporization gas for the purpose of its liquefaction and mixing with the liquid hydrogen produced.

As illustrated in FIG. 2, the downstream end of the recuperation duct 12 is connected to the hydrogen circuit 2 in the interior of the cold box 18. In addition, before it is connected to the hydrogen circuit 2, the downstream end of the recuperation duct 12 is in thermal exchange with at least one exchanger 5, 6 of the series of heat exchangers 3, 4, 5, 6, for the purpose of its cooling.

As illustrated, the series of heat exchangers 3, 4, 5, 6 of the cold box preferably comprises a plurality of heat exchangers positioned in series between the upstream end 21 and the downstream end 22 of the hydrogen circuit 2. The connection of the downstream end of the recuperation duct 12 to the hydrogen circuit 2 is situated for example downstream from a first passage of the hydrogen circuit 2 in the final heat exchanger 6 in series.

As illustrated, this first passage of the hydrogen circuit 2 in the final heat exchanger 6 preferably comprises a section 29 for catalysis of the hydrogen, which section is configured to carry out the conversion of at least part of the Ortho hydrogen into Para hydrogen. Downstream from this first passage in the catalysis section 29 of the heat exchanger 6, the hydrogen circuit 2 preferably comprises an expansion unit 30, such as an expansion valve for example.

Similarly, the downstream end of the recuperation duct 12 preferably comprises a unit 20 for expansion of the flow of vaporization gas, which unit is situated between the portion in thermal exchange with the exchanger(s) 5, 6 of the series of heat exchangers, and the connection to the hydrogen circuit 2.

As illustrated, downstream from the connection, the hydrogen circuit 2 which has received the cooled and expanded vaporization gas can carry out a second passage in the final heat exchanger 6, for the purpose of supplementary cooling. This second heat exchanger is preferably situated in another section of the heat exchanger 6 which does not comprise a catalysis section.

As illustrated, downstream from this second passage in the final heat exchanger 6, the hydrogen circuit 2 can comprise a unit 23 for expansion of the flow of hydrogen. This expansion unit 23 is for example a final expansion unit in the cold box, and comprises for example an expansion valve and/or a cryogenic expansion turbine. The fluid thus expanded is liquefied, and can then be supplied to the cryogenic store via appropriate ducts.

This configuration makes it possible to prevent expansion of gaseous hydrogen, which would tend to heat it. According to the above configuration, the gaseous hydrogen recuperated is expanded in two stages in the liquefier. A first time is at the outlet from the final catalytic heat exchanger 6, then it is during a second passage in the exchanger 6 without catalytic conversion, and finally it is with a final expansion up to the final pressure level specified for the store 8.

FIG. 1 and FIG. 3 to FIG. 8 illustrate different configurations or operations which can be implemented by the facility 1.

As illustrated, the recuperation duct 12 preferably comprises a first upstream end connected to an upper end of the store 8, and a second upstream end designed to be connected to the upper end of a mobile tank 19. For example, the first and second upstream ends of the recuperation duct 12 are connected to the downstream end of the recuperation duct, respectively via two distinct duct branches 121, 122. These two branches 121, 122 can be provided with respective valves 221, 222.

In addition, the downstream end 22 of the hydrogen circuit can comprise two ends connected respectively to the lower and upper parts of the store via respective valves 201, 202, in order to fill the store 8 in its liquid phase or in its gaseous phase.

In addition, as illustrated, the drawing-off duct 11 can comprise an upstream end connected to the store 8 (lower part), which end is preferably provided with a valve 111 and two downstream ends. A first downstream end, provided with a valve 112, can be designed to be connected detachably to a tank to be filled with liquid (in the lower part). The second downstream end of the drawing-off duct 11 can be provided with a valve 113, and can be connected to the second upstream end of the duct 12 for recuperation of gas (branch 122).

This fluidic connection between the drawing-off duct 11 and the branch 122 makes it possible to inject liquid into the tank 19 at its upper part (filling in rain for example).

In the different configurations illustrated, the closed valves are represented in black, whereas the open valves are represented in white.

In the configuration in FIG. 1 there is no mobile tank to be filled.

The hydrogen of the source 23 is liquefied by the liquefier 31, and distributed to the store(s) 8 by the piping of the circuit 2. The valves 222 for recuperation of gas from the mobile tank(s) are closed. The hydrogen can be supplied to the store in its lower part. The hydrogen supplied by the liquefier 31 can be undercooled in order to maintain the pressure of the store 8, and withstand the thermal inputs thereof. The pressure of the store 8 can be regulated by the valves 201 and 202, which make it possible to assure filling from the bottom and/or from the top. As illustrated, the valve 221 of the first downstream end of the duct for recuperation of vaporization gas from the store 8 can be open in order to keep this duct 121, 12 cold.

In the configuration of FIG. 3, a mobile tank 19 to be filled is connected to the first downstream end of the drawing-off duct 11. This tank 19 is also connected to the second upstream end of the recuperation duct 12 (branches 122).

After connection of the tank 19 to the drawing-off duct 11, and to the duct 12 for recuperation of gas, the pressure in the tank 19 (for example of between 3 and 10 bars) can be reduced to a level lower than the pressure P8 in the tank 8 (for example to a few millibars below P8). This is carried out in order to allow the tank 19 to be filled with liquid from the store by pressure differential (without a pump).

The hydrogen which is present in the tank 19 is generally mostly gaseous (from 1 to 10% of liquid phase) and has a temperature of between 100K and 25K. The first part of the hot hydrogen recuperated can be sent to a recuperation system 32 via a line in parallel provided with a valve 322.

When the temperature in the tank 19 has dropped to a determined level, for example between 50K and 30K, it is possible to send the gas to the liquefier (valve 222 open).

This gaseous hydrogen will be liquefied in the liquefier 31 as previously described, and will be able to return to the store 8, provided that the pressure in the tank 19 is higher than the pressure of the store 8 (plus the losses of loads of the circuits).

In order to finalize the depressurization of the tank 19, it may be necessary to decrease its pressure to below the pressure of the store 8. There are several possibilities. In a first option, the depressurization of the tank 19 can be carried out towards the recuperation system 32, cf. FIG. 4.

According to another possibility, balancing of pressures can be carried out between the tank 19 and the store 8 (cf. FIG. 5: valves 222 and 221 open) followed by pressurization of the store by the liquefier (valve 201 open cf. FIG. 5). In other words, the gas is transferred from the tank 19 to the store via the branches 122 then 121 of the recuperation duct 12.

At the end of this first sequence, the tank 19 has reached a pressure P19 lower than the pressure P8 of the store 8.

Then, as illustrated in FIG. 6, the tank 19 can be filled with liquid. The liquid hydrogen can be transferred from the store 8 into the upper part of the tank 19 via the drawing-off duct 11 and the valve 113 of the branch which is connected to the duct for recuperation of gas.

The liquid coming from the store 8 can be sufficiently cold to maintain the pressure P19 in the tank 19 by condensing the vapors there. The pressure of the store 8 can be maintained by the injection of liquid hydrogen coming from the liquefier in the vapor phase of the store (filling from the top via the branch 121 of the duct 12 for recuperation of gas with the valve 221 open). This hydrogen can come from the hydrogen circuit 2 which has been expanded and heated in a heat exchanger. The corresponding cold can thus be recuperated in the interior of the liquefier 31 during this phase rather than injecting heat into the store 8 via a pressurization unit (“PBU”).

At the end of this sequence, the tank 19 can still have a pressure P19 which is close to the pressure P8 of the store 8. The tank 19 is filled to more than half its capacity (for example between 85% and 95% of its capacity), but its pressure should preferably be reduced in order to be able to take to the road and not lose hydrogen during the journey.

The pressure of the tank 19 when on the road may depend on local regulations.

This depressurization can be carried out for example via degassing to the recuperation system 32 (valve 322 open). The pressure of the tank 19 can be brought for example to 1.5 bars. Simultaneously, the facility can continue to control the pressure of the store 8, for example by injection of undercooled liquid hydrogen at the top and/or at the bottom of the store 8, by controlling the valves 202 and 201. Cf. FIG. 7.

FIG. 8 illustrates a variant embodiment which is distinguished from FIG. 1 only in that the branch 122 of the recuperation duct 12, which is designed to recuperate the vaporization gas from the tank 19, comprises a compression unit 24, such as a compressor of a cryogenic type (cold compressor which is configured to compress vapors at temperatures of between 25 and 100K). As illustrated, a bypass duct 124 of the compressor 24 and a series of valves 224, 324 can be provided to assure or not assure the passage of all or part of the flow into the compressor 24.

This compression unit 24 permits better recuperation of the vapors from the tank 19 on the duct 12 for recuperation of the vapors to the liquefier 31.

This compression unit 24 makes it possible to increase the pressure of the hydrogen vapors recuperated for the purpose of their recuperation in the store 8 and/or the liquefier 31, during phases when the pressures available in the tank 19 are not sufficient to assure this transfer by difference of pressure. The advantage of a cryogenic compressor 24 in comparison with a conventional compressor at ambient temperature is its size, which is reduced because of the greater density of the cold hydrogen. The cold temperature of the hydrogen is maintained during the compression, and the compressed cold hydrogen can be recuperated easily in the store 8 or to the liquefier 31, in order to be liquefied once more.

The configuration of FIG. 8 corresponds to the configuration of FIG. 1. The hydrogen of the circuit 2 is liquefied by the liquefier 31, and is distributed in the store 8. This hydrogen can be undercooled in order to control and maintain the pressure in the store 8, and withstand the thermal inputs thereof. This pressure of the store 8 can be regulated via the valves 202, 201 (filling from the top/bottom). As illustrated, the valve 221 on the branch for recuperation of the vaporization gas from the store 8 can be open, in order to keep this line cold. The valves 222, 322 of the branch for recuperation of the vaporized gas from the tanks 19 are closed The compressor 24 is preferably at a standstill.

FIG. 9 illustrates a configuration for depressurization of a tank 19 to be filled which corresponds to the configuration of FIG. 3. It should be noted that, in this embodiment represented, the drawing-off duct 11 is not connected to the upper part of the tank (via the branch 122), but it can be appreciated that it could be.

After connection of the tank to the drawing-off 11 and gas recuperation 12, 122 ducts, the pressure (for example from 3 to 10 bars) of the tank 19 can be reduced to below the pressure of the store 8. The hydrogen which is present in the tank 19 is in principle mostly gaseous (from 1 to 10% liquid phase) and at a temperature for example of between 100K and 25K. A first part of the hot hydrogen recuperated can be sent to the recuperation system 32 (valve 322 open). Once the temperature of the gas in the tank 19 has dropped (for example between 50K and 30K), the recuperated gas can be sent to the liquefier 31 (duct 12, valves 222, 224 open). This hydrogen will be liquefied as previously described (passage(s) in the exchanger 6 and expansion), then will supply the store 8 provided that the pressure of the tank 19 remains higher than the pressure in the store 8 (plus the losses of loads of the circuits concerned). The compressor 24 is preferably not used in this first depressurization phase, but can be cooled by the vapors returning to the liquefier 31.

As illustrated in FIG. 10, in order to finalize the depressurization of the tank 19, this pressure can be decreased to below the pressure of the store 8. The compressor 24 can be used to aspirate the vapors from the tank 19, and send them to the store 8. The return to the liquefier 31 can be closed during this phase. The pressure of the store 8 can still be regulated by the valves 202, 201. There is thus transfer of gas from the tank 19 to the store 8.

Upon completion of this step, the tank 19 has reached a pressure lower than the pressure of the store 8. This represents the main part of the filling of the tank 19 with liquid. The liquid hydrogen is transferred from the store 8 to the tank 19 by the drawing-off duct 11 (valve 111 open). The pressure of the store 8 can be maintained by the injection of hydrogen coming from the liquefier 31 (valves 201 and/or 202). The pressure of the tank 19 can be maintained below the pressure of the store 8 thanks to the compressor 24. Cf. FIG. 10.

At the end of this step, the tank 19 can still be at a pressure close to the pressure of the store 8. The level of filling of the tank 19 is relatively substantial (for example between 85% and 95%), but its pressure may need to be reduced in order to be able to take to the road and not lose hydrogen during the journey. This pressure when on the road may depend on local regulations. The compressor 24 can make it possible to reduce this pressure in the tank 19 to the starting pressure required (without use of the valve 332 towards the recuperation system, or by avoiding the loss of hydrogen during the journey). The gas in the tank 19 is pumped towards the store 8 (cf. FIG. 12).

The cold compressor 24 can also be used to reduce the pressure of the store 8 without providing a supply of undercooled hydrogen. This increases the production capacity of the liquefier.

FIG. 13 illustrates a variant embodiment of the circuit returning the vaporization gases recuperated within the cold box 18 of the liquefier 31. For the sake of simplification, only part of the cold box 18 and the circuits are represented in FIG. 13. The embodiment of FIG. 13 is distinguished from that of FIG. 2 in that the downstream end of the recuperation duct 12 comprises, upstream from the connection to the hydrogen circuit 2, a catalysis section 25 (for example a catalytic converter) which is configured to carry out the conversion of at least part of the Para hydrogen into Ortho hydrogen.

In addition, the recuperation duct 12 comprises a bypass portion 26 and a series of valves 27, 28 configured to assure or not assure the passage of the flow of vaporization gas into the catalysis section 25.

The specification required for the hydrogen liquefiers 31 is to provide a minimal conversion of approximately 95% Para for the hydrogen at the outlet of the liquefier. The presence of catalyst in the final exchanger(s) 5, 6 in general permits conversion of between 98% to 100% depending on the pressure of the hydrogen.

The gaseous hydrogen returning from the tanks 19 to be filled is obtained by the vaporization of liquid, and is generally constituted by hydrogen in Para form, in a proportion of between 98% and 100%.

In certain cases, the facility 1 is not suitable for the recuperation of excessively hot hydrogen vapors, since this can disrupt the operation of the liquefier 31.

These recuperated vapors can be cooled by using the Ortho to Para conversion which is the inverse of that carried out in the liquefier for the flow of the hydrogen circuit 2.

Thus, for example, these recuperated vaporization gases can have a temperature of between 50K and 25K. The higher this temperature is, the further the hydrogen is from its point of equilibrium at this temperature (20K for hydrogen at 98% para), and the more the Para to Ortho conversion will cool the hydrogen.

The vapors are thus converted from the Para form to the Ortho form then liquefied in the heat exchanger 6/expansion device 20, and are then mixed with the hydrogen of the circuit 2, before supplying the store 8 (as previously described).

The use of a catalytic converter 25 of this type is in principle necessary only when the gaseous hydrogen arrives hot enough (for example at the start of depressurization of the tank 19 to be filled) and sufficiently under pressure (pressure typically between 3 and 10 bars). The bypass system 26, 27, and in particular the valve(s) can be configured to assure passage into the conversion catalysis according to the return temperature of the gas, which can be measured by a temperature sensor 33 in the recuperation duct 12.

Thus, when the temperature measured becomes cold enough, or the pressure decreases in the recuperation duct (end of the depressurization of the tank 19), the valve 28 of the circuit is closed, and the direct supply valve 27 of the exchanger 6 is opened in order to reduce the loss of load of the system.

This control of the pressurization of the tanks 19 limits the flow in relation to the capacity of the liquefier (control of the outlet temperature of the exchanger of the reliquefied gas can be provided).

It will be appreciated that this embodiment can be applied to the embodiments and steps described above.

In addition, the above examples are non-limiting. Thus, for example, the facility could comprise a plurality of stores 8 and/or a plurality of ducts for filling 11 and recuperation 12 of vaporized gases.

A cold compressor 24 could be positioned in parallel with the recuperation duct, for transfer of the gas to the liquefier, in particular in the case when a plurality of tanks are processed simultaneously.

While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.

The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.

“Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.

“Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.