Installation and process for supplying liquefied hydrogen

Abstract

The invention relates to a liquefied hydrogen supply installation (1) comprising: a gaseous hydrogen source (2); a liquefier (3) configured to deliver liquefied hydrogen; at least one liquefied hydrogen storage tank (4) configured to receive liquefied hydrogen from the liquefier (3); a transfer line (5) configured to allow the transfer of liquefied hydrogen from the storage tank (4) to a filling tank (6), the transfer line (5) being fluidly connected to the storage tank (4) by at least one first purge line (23) configured to allow the transfer of gaseous hydrogen from the storage tank (4) to the transfer line (5). Abstract figure: Fig. 1

Description

Title of the invention: Installation and method for supplying liquefied hydrogen

[0001] The present invention relates to a liquefied hydrogen supply installation and a method of supplying liquefied hydrogen by means of such an installation.

[0002] A hydrogen liquefier is generally configured to produce liquid hydrogen without it being possible to guarantee continuous operation. Indeed, a liquefier is generally configured to be selectively in a first state in which it is in operation and in a second state in which it is stopped. In the first state, the liquefier produces and delivers liquefied hydrogen and / or pure medium-pressure hydrogen gas. Hydrogen is pure when its degree of purity is greater than or equal to 99.9999 mol%. Hydrogen gas is said to be at medium pressure when its pressure is greater than or equal to 3.6 bara, for example between 3.6 bara and 7 bara. Liquefied hydrogen is pure. In the second state, the liquefier produces and delivers impure hydrogen gas, the hydrogen gas being in particular at a temperature greater than or equal to -150 °C. Hydrogen gas is impure when it contains an impurity level greater than 1 ppm.In the second state, the liquefier can also deliver a fluid with a flow rate lower than a minimum threshold, the minimum threshold being for example 1 kg per hour. In the second state, the flow rate of the fluid leaving the liquefier can be zero.

[0003] The liquid hydrogen produced by the liquefier is therefore stored in one or more liquefied hydrogen storage tanks from which tanks to be filled, such as semi-trailers, are filled. Thus, even when the liquefier is stopped, it remains possible to ensure filling of one or more tanks to be filled.

[0004] When filling a tank to be filled, it is necessary to carry out one or more steps of sweeping and / or purging the transfer lines used for the transfer of liquefied hydrogen, from the storage tank to the tank to be filled. These sweeping and / or purging steps are carried out with pure hydrogen gas coming from the liquefier. These sweeping and / or purging steps are necessarily accompanied by compressions / expansions with pure, medium-pressure hydrogen gas coming from the liquefier, to remove an inert gas such as nitrogen.

[0005] A problem arises when the liquefier is stopped, that is to say when it is not able to supply pure, medium-pressure hydrogen gas. Indeed, under these conditions, it becomes impossible to carry out compressions / expansions during the stages of sweeping and / or purging the transfer lines.

[0006] The present invention aims to effectively remedy these drawbacks by proposing a liquefied hydrogen supply installation comprising: - a source of gaseous hydrogen; - a liquefier configured to be supplied with gaseous hydrogen by the source and to deliver liquefied hydrogen, the liquefier being configured to be selectively in a first state in which it is operating and in a second state in which it is stopped; - at least one liquefied hydrogen storage tank configured to receive liquefied hydrogen from the liquefier, via a supply line and being configured to store the liquefied hydrogen; - at least one transfer line configured to allow the transfer of liquefied hydrogen from the storage tank to a tank to be filled via at least one transfer line fluidly connecting the storage tank to the transfer line, the transfer line being further fluidly connected to the storage tank by at least one first purge line configured to allow the transfer of low-pressure hydrogen gas from the storage tank to the transfer line, the low-pressure hydrogen gas having in particular a pressure less than or equal to 3.5 bara, the low-pressure hydrogen gas belonging to a gaseous headspace of the storage tank.

[0007] The invention thus makes it possible to carry out a sweep and / or a purge of equipment in a liquefaction installation such as a transfer line, when the liquefier is stopped, that is to say when it delivers a fluid with a flow rate lower than a minimum threshold, the minimum threshold being for example equal to 1 kg per hour, or when it delivers impure hydrogen, the impure hydrogen having in particular an impurity level greater than 1 ppm or being at a temperature greater than or equal to -150°C.

[0008] According to one embodiment, the low pressure hydrogen has a pressure of between 1.0 and 3.5 bara.

[0009] According to one embodiment, the installation comprises a control unit configured to selectively allow the transfer of low-pressure hydrogen gas from the storage tank to the transfer line, the low-pressure hydrogen gas belonging to a gaseous headspace of the storage tank;

[0010] According to one embodiment, the control unit is configured to selectively allow the transfer of medium pressure pure hydrogen gas from the liquefier to the transfer line.

[0011] According to one embodiment, the medium pressure pure hydrogen gas coming from the liquefier has a pressure of between 3.6 bara and 7 bara.

[0012] According to one embodiment, the medium pressure pure hydrogen gas coming from the liquefier has a degree of purity greater than or equal to 99.9999 mol%.

[0013] According to one embodiment, the supply line is provided with a supply valve to allow or prevent liquefied hydrogen from the liquefier from entering the storage tank.

[0014] According to one embodiment, the transfer line is provided with a transfer valve to allow or prevent liquefied hydrogen from the storage tank from being transferred into the transfer line.

[0015] According to one embodiment, the purge line is provided with a purge valve to allow or prevent the transfer of low pressure hydrogen gas from the gaseous headspace of the storage tank to the transfer line.

[0016] According to one embodiment, the installation comprises a compression / expansion pipe provided with a compression / expansion valve, fluidically connecting the liquefier to the transfer line, the compression / expansion pipe being configured to allow the transfer of medium-pressure pure gaseous hydrogen, coming from the liquefier into the transfer line.

[0017] According to one embodiment, the installation comprises a collection pipe provided with a collection valve, fluidly connecting the transfer line to the liquefier, the collection pipe being configured to allow the transfer of a gas collected in the gaseous air of the tank to be filled, to the liquefier, with a view to its recycling by the liquefier.

[0018] According to one embodiment, the tank to be filled comprises a mobile tank such as a tanker truck.

[0019] According to one embodiment, the installation comprises a source of inert gas such as nitrogen or helium, configured to deliver inert gas, the installation being configured to allow transfer into the transfer line of at least a portion of the inert gas delivered by the source of inert gas, in particular via an inert gas pipe provided with an inert gas valve.

[0020] The invention further relates to a method for supplying liquefied hydrogen by means of an installation as described above, the liquefier being in the second state, the method comprising the steps of: - a) flushing and / or purging the transfer line with an inert gas such as nitrogen or helium, from a source of gaseous nitrogen or gaseous helium, in particular as long as the transfer line has an O2 level greater than or equal to 1 ppm; - b) flush and / or purge the transfer line with low pressure hydrogen gas from the gaseous headspace of the storage tank, in particular as long as the transfer line has an N2 level greater than or equal to 5 ppm or as long as the transfer line has a He level greater than or equal to 5 ppm, step b) being in particular devoid of compression / expansion of the low pressure hydrogen gas as long as the transfer line has a N2 level greater than or equal to 5 ppm or as long as the transfer line has a He level greater than or equal to 5 ppm.

[0021] According to one embodiment, steps a) and b) are carried out successively, one after the other.

[0022] According to one embodiment, the pressure in the first purge line is constant over time or it decreases over time, throughout the duration of step b).

[0023] According to one embodiment, the method comprises, after step b), a step of transferring liquefied hydrogen from the liquefier to the tank to be filled or from the storage tank to the tank to be filled.

[0024] According to one embodiment, the liquefier being in the first state, the method comprises the steps of: - c) flushing and / or purging the transfer line with an inert gas such as nitrogen or helium, from a source of gaseous nitrogen or gaseous helium, in particular as long as the transfer line has an O2 level greater than or equal to 1 ppm; - d) sweeping and / or purging the transfer line with medium-pressure pure hydrogen gas coming from the liquefier, in particular as long as the transfer line has an N2 level greater than or equal to 5 ppm or as long as the transfer line has a He level greater than or equal to 5 ppm, said step d) comprising a sweep with medium-pressure pure hydrogen gas coming from the liquefier followed by alternating compressions / expansions with medium-pressure pure hydrogen gas coming from the liquefier.

[0025] According to one embodiment, the method comprises, after step d), a step of transferring liquefied hydrogen from the liquefier to the tank to be filled or from the storage tank to the tank to be filled.

[0026] According to one embodiment, the method comprises, prior to step a), or prior to step c), a step x) of determining the operating state of the liquefier between the first state and the second state and a sweep / purge of the transfer line either by implementing steps a) and b) or by implementing steps c) and d).

[0027] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only for illustrative purposes but in no way limit the invention.

[0028] [Fig-1] [Fig.l] is a schematic representation of an installation according to the invention; and

[0029] [Fig.2] [Fig.2] is a schematic representation of a method according to the invention.

[0030] With reference to [Fig.l], a liquefied hydrogen supply installation 1 comprises a liquefier 3 and a source 2 of gaseous hydrogen. The liquefier 3 is configured to be supplied with gaseous hydrogen by the source 2 and to deliver liquefied hydrogen.

[0031] The liquefier 3 is configured to be selectively in a first state in which it is operating by delivering liquefied hydrogen and / or by delivering medium pressure pure hydrogen gas, and in a second state in which it is stopped.

[0032] In the first state, the medium pressure pure hydrogen gas has a degree of purity greater than or equal to 99.9999 mol%.

[0033] In the first state, the liquefier 3 delivers pure medium-pressure hydrogen gas with a pressure between 3.6 bara and 7 bara.

[0034] In the second state, the liquefier 3 produces and delivers impure hydrogen gas, the hydrogen gas being in particular at a temperature greater than or equal to -150°C. The hydrogen gas is impure when it contains an impurity level greater than 1 ppm.

[0035] In the second state, the liquefier can further deliver a fluid with a flow rate lower than a minimum threshold, the minimum threshold being for example equal to 1 kg per hour. In the second state, the flow rate of the fluid at the outlet of the liquefier can be zero.

[0036] The installation 1 comprises at least one storage tank 4 for liquefied hydrogen configured to receive liquefied hydrogen from the liquefier 3, via a supply pipe 21 and being configured to store the liquefied hydrogen.

[0037] The installation 1 further comprises at least one transfer line 5 configured to allow the transfer of liquefied hydrogen from the storage tank 4 to a tank to be filled 6 via at least one transfer pipe 22 fluidly connecting the storage tank 4 to the transfer line 5, the transfer line 5 being further fluidly connected to the storage tank 4 by at least one first purge pipe 23 configured to allow the transfer of low-pressure gaseous hydrogen from the storage tank 4 to the transfer line 5, the low-pressure gaseous hydrogen belonging to a gaseous headspace of the storage tank 4.

[0038] Low pressure hydrogen gas has a pressure less than or equal to 3.5 bara.

[0039] The supply line 21 is provided with a supply valve 11 to allow or prevent liquefied hydrogen from the liquefier 3 from entering the storage tank 4.

[0040] The transfer line 22 is provided with a transfer valve 12 to allow or prevent liquefied hydrogen from the storage tank 4 from being transferred into the transfer line 5.

[0041] The purge line 23 is provided with a purge valve 13 to allow or prevent the transfer of low pressure hydrogen gas from the gaseous headspace of the storage tank 4 to the transfer line 5.

[0042] The installation 1 comprises a compression / expansion pipe 24 equipped with a compression / expansion valve 14, configured to allow the transfer of pure gaseous hydrogen coming from the liquefier 3 into the transfer line 5.

[0043] The installation 1 comprises a collection pipe 25 provided with a collection valve 15, configured to allow the transfer of a gas collected in the gaseous air of the tank to be filled 6, to the liquefier 3, with a view to its recycling by the liquefier 3.

[0044] The tank to be filled 6 comprises a mobile tank such as a tanker truck.

[0045] The installation comprises a source of inert gas 7 such as nitrogen or helium.

[0046] The installation is configured to allow a transfer in the transfer line 5 of at least a portion of the inert gas delivered by the inert gas source 7, via an inert gas pipe 8 provided with an inert gas valve 9.

[0047] [Fig.2] represents a method of supplying liquefied hydrogen by means of an installation 1 as described above.

[0048] The liquefier 3 being in the second state, the method comprises the steps: - a) sweeping and / or purging the transfer line 5 with an inert gas such as nitrogen or helium, coming from a source of gaseous nitrogen or gaseous helium, in particular as long as the transfer line 5 has an O2 level greater than or equal to 1 ppm; - b) sweeping and / or purging the transfer line 5 with low-pressure hydrogen gas coming from the gaseous overhead of the storage tank 4, in particular as long as the transfer line 5 has an N2 level greater than or equal to 5 ppm or as long as the transfer line 5 has an He level greater than or equal to 5 ppm, step b) being in particular devoid of compression / expansion of the low-pressure hydrogen gas as long as the transfer line has an N2 level greater than or equal to 5 ppm or as long as the transfer line has an He level greater than or equal to 5 ppm.

[0049] Steps a) and b) are carried out successively, one after the other.

[0050] The pressure in the first purge line 23 is constant over time or it decreases over time, throughout the duration of step b).

[0051] The method comprises, after step b), a step of transferring liquefied hydrogen from the liquefier 3 to the tank to be filled 6 or from the storage tank 4 to the tank to be filled 6.

[0052] The liquefier 3 being in the first state, the method comprising the steps: - c) sweeping and / or purging the transfer line with an inert gas such as nitrogen or helium, from a source of gaseous nitrogen or gaseous helium, in particular as long as the transfer line has an O2 level greater than or equal to 1 ppm; - d) sweeping and / or purging the transfer line with medium-pressure pure hydrogen gas coming from the liquefier 3, in particular as long as the transfer line has an N2 level greater than or equal to 5 ppm or as long as the transfer line has a He level greater than or equal to 5 ppm, said step d) comprising a sweep with hydrogen gas coming from the liquefier 3 followed by alternating compressions / expansions with medium-pressure pure hydrogen gas coming from the liquefier 3.

[0053] The method comprises, after step d), a step of transferring liquefied hydrogen from the liquefier 3 to the tank to be filled or from the storage tank 4 to the tank to be filled.

[0054] The method comprises, prior to step a), or prior to step c), a step x) of determining the operating state of the liquefier between the first state and the second state and a sweep / purging of the transfer line either by implementing steps a) and b) or by implementing steps c) and d).

Claims

Claims

1. Installation (1) for supplying liquefied hydrogen comprising: - a source (2) of gaseous hydrogen; - a liquefier (3) configured to be supplied with gaseous hydrogen by the source (2) and to deliver liquefied hydrogen, the liquefier (3) being configured to be selectively in a first state in which it is in operation and in a second state in which it is stopped; - at least one storage tank (4) for liquefied hydrogen configured to receive liquefied hydrogen from the liquefier (3), via a supply line (21) and being configured to store the liquefied hydrogen;- at least one transfer line (5) configured to allow the transfer of liquefied hydrogen from the storage tank (4) to a tank to be filled (6) via at least one transfer pipe (22) fluidly connecting the storage tank (4) to the transfer line (5), the transfer line (5) being further fluidly connected to the storage tank (4) by at least one first purge pipe (23) configured to allow the transfer of low-pressure hydrogen gas from the storage tank (4) to the transfer line (5), the low-pressure hydrogen gas having in particular a pressure less than or equal to 3.5 bara, the low-pressure hydrogen gas belonging to a gaseous headspace of the storage tank (4).;

2. Method for supplying liquefied hydrogen by means of an installation (1) according to one of the preceding claims, the liquefier (3) being in the second state, the method comprising the steps of: - a) sweeping and / or purging the transfer line (5) with an inert gas such as nitrogen or helium, coming from a source of gaseous nitrogen or gaseous helium, in particular as long as the transfer line (5) has an O2 level greater than or equal to 1 ppm; - b) sweeping and / or purging the transfer line (5) with low pressure hydrogen gas coming from the gaseous headspace of the storage tank (4), in particular as long as the transfer line (5) has an N2 level greater than or equal to 5 ppm or as long as the transfer line (5) has an He level greater than or equal to 5 ppm, step b) being in particular devoid of compressions / expansions of the low pressure hydrogen gas as long as the transfer line (5) has an N2 level greater than or equal to 5 ppm or as long as the transfer line (5) has an He level greater than or equal to 5 ppm.

3. Method according to the preceding claim, steps a) and b) being carried out successively, one after the other.

4. Method according to one of claims 2 to 3, the pressure in the first purge line (23) being constant over time or decreasing over time, throughout the duration of step b).

5. Method according to one of claims 2 to 4, comprising after step b), a step of transferring liquefied hydrogen from the liquefier (3) to the tank to be filled (6) or from the storage tank (4) to the tank to be filled (6).

6. Method according to one of claims 2 to 5, the liquefier (3) being in the first state, the method comprising the steps of: - c) sweeping and / or purging the transfer line (5) with an inert gas such as nitrogen or helium, coming from a source of gaseous nitrogen or gaseous helium, in particular as long as the transfer line (5) has an O2 level greater than or equal to 1 ppm; - d) sweeping and / or purging the transfer line (5) with medium-pressure pure hydrogen gas coming from the liquefier (3), in particular as long as the transfer line (5) has an N2 level greater than or equal to 5 ppm or as long as the transfer line (5) has a He level greater than or equal to 5 ppm, said step d) comprising a sweep with medium-pressure pure hydrogen gas coming from the liquefier (3) followed by alternating compressions / expansions with medium-pressure pure hydrogen gas coming from the liquefier (3).

7. Method according to the preceding claim, comprising after step d), a step of transferring liquefied hydrogen from the liquefier (3) to the tank to be filled (6) or from the storage tank (4) to the tank to be filled (6).

8. Method according to one of claims 2 to 7, comprising prior to step a), or prior to step c), a step x) of determining the operating state of the liquefier between the first state and the second state and a sweep / purging of the transfer line (5) either by implementing steps a) and b) or by implementing steps c) and d).

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