Architecture for loading liquid hydrogen trailers

Abstract

A method for filling a hydrogen transport trailer (40) is provided, which may include the steps of: transporting liquid hydrogen from liquid hydrogen storage containers (20, 80) to the hydrogen transport trailer (40) via a liquid transfer line (26); and transporting gaseous hydrogen from the gas head space (15) of the hydrogen transport trailer (40) to the liquid hydrogen storage container (20) via a gas transfer line (42), wherein the liquid hydrogen storage container (20) is configured to be in fluid communication with a hydrogen liquefaction unit, thereby configuring the liquid hydrogen storage container (20) to receive liquid hydrogen from the hydrogen liquefaction unit.

Description

Technical Field

[0001] Cross - Reference to Related Applications This patent application claims priority to U.S. Provisional Patent Application No. 63 / 523,537, filed on June 27, 2023, the entire disclosure of which is incorporated herein by reference.

Background Art

[0002] Loading a liquid hydrogen trailer is a time - consuming process and also leads to a large amount of hydrogen release. When the liquid hydrogen trailer arrives at the liquefaction device, it has a significant amount of hydrogen gas and needs to be managed. To fill the trailer with hydrogen, often the gaseous hydrogen in the trailer is removed to lower the trailer's pressure, which is generally referred to as depressurization. Then, the trailer enters the loading stage.

[0003] Even when the trailer is "empty", there is a small amount of liquid hydrogen and a large amount of gaseous hydrogen in the trailer. The gaseous hydrogen should be removed so that the trailer can be filled with liquid. In addition, the flow entering the trailer typically contains a small amount of hydrogen gas, which is due to 1) some heat being absorbed in the piping, which vaporizes the liquid hydrogen to gaseous hydrogen, and 2) the incoming flow being saturated at a pressure higher than the trailer's pressure, which causes the liquid flow to flash into a two - phase fluid (liquid and gas). The gas generated by the cooling and flushing of the piping should be removed from the trailer so that additional liquid hydrogen can be filled into the trailer.

[0004] The amount of gas and the gas generation rate vary, and for the depressurization and loading of the trailer to be carried out as quickly as possible, the gas should be removed as soon as it is generated. If the gas is not removed when it is generated, this step will take an unnecessarily long time.

[0005] For example, during depressurization, a large amount of hydrogen gas (approximately 200 kg) is generated that must be immediately removed from the trailer. If the flow rate of hydrogen gas removed from the trailer is slow, this operation will take longer. During loading, hydrogen gas from the steam space, as well as hydrogen gas generated by cooling and flushing the piping, can fill the gas space of the trailer and increase the pressure inside the trailer. When the pressure inside the trailer increases, the flow of liquid hydrogen from the liquid hydrogen storage container slows down, and the loading step takes longer.

[0006] Current methods for removing gas from trailers are either 1) exhausting the gas from the trailer into the atmosphere, or 2) compressing the gas from the trailer to a higher pressure so that it can be used in the liquefaction process. Exhausting the gas into the atmosphere allows the gas to be removed from the trailer at a very high flow rate (essentially immediately after the gas is generated), and the pressure inside the trailer is maintained at approximately atmospheric pressure. Compressing the gas from the trailer to a high pressure is done at a constant flow rate in a compressor, raising the pressure inside the trailer to about 5 psig, which provides sufficient pressure for the compressor to draw in. Compression of the gas limits the flow rate of gas that can be removed from the trailer, and this limited flow rate slows down the trailer depressurization and loading process.

[0007] Another factor affecting the trailer loading speed is the pressure drop between the liquid hydrogen storage container and the trailer. After depressurization, when excess gas due to loading is removed from the trailer, the resulting pressure drop determines the flow rate of liquid hydrogen from the liquid hydrogen storage container to the trailer. Assuming constant piping resistance and constant discharge conditions for the liquid hydrogen storage container, the pressure drop correlates with the flow rate of liquid hydrogen from the liquid hydrogen storage container to the trailer. To load the trailer more quickly, the pressure drop from the liquid hydrogen storage container to the trailer should be maximized. Liquid hydrogen storage containers are typically held at approximately 10–20 psig. The resulting pressure drop depends on the method used to remove gas from the trailer. When gas is removed from the trailer using a compressor, the resulting pressure drop is 5–15 psi (10–20 psig minus 5 psig). When trailer gas is removed by venting, the resulting pressure drop is 10–20 psi. A trailer can typically carry approximately 4,000 kg, and the flow rate of liquid hydrogen from the liquid hydrogen storage container to the trailer is shown below.

[0008] [Table 1]

[0009] The liquid hydrogen transfer time can be 2.5 to 4.5 hours, and this does not include hose connection, valve operation, or purging / cooling sequences. The total time required for filling the trailer consists of depressurization and loading, and therefore the total time is typically close to 6 hours.

[0010] A solution is needed to recover all gas into the liquefaction unit while shortening the time required for depressurization and loading of the trailer.

[0011] While large compressors can recover gas, they do not improve trailer loading time or depressurization time compared to exhaust during depressurization (assuming the resulting pressure drop is the same). In addition, compressors with high flow rates and low suction pressures are excessively expensive, and compressors larger than the current size are not economically viable.

[0012] The combination of a liquid pump and a gas compressor allows for rapid trailer loading and avoids the waste of hydrogen gas from the trailer. However, the compressor's CAPEX needs to be even larger than that of a compressor used to recover more gaseous hydrogen, because the pump increases the liquid hydrogen flow rate, requiring a very high flow rate of gaseous hydrogen to be removed from the trailer by the compressor. Centrifugal liquid hydrogen pumps are also a relatively unproven component, and there are no proven liquid hydrogen pumps that can operate at very low NPSH (Potentially Non-Proven High Saturation) levels.

[0013] In general, the prior art has the following problems: Hydrogen released into the atmosphere is wasted rather than recovered, which leads to a loss of value, increased impact on global warming, and increased safety issues due to the emission of large amounts of hydrogen. • As a result of slow loading, a significant amount of manpower is required to supervise the loading process for extended periods. Furthermore, the slow loading speed necessitates a large number of loading bays to meet the production capacity of the liquefaction equipment, thereby increasing capital investment for liquid hydrogen production.

[0014] The available solutions are limited by the high CAPEX of the compressor, and there are no proven liquid hydrogen pumps that operate with very low effective suction heads (NPSH). [Overview of the project] [Problems that the invention aims to solve]

[0015] As mentioned earlier, the recycled hydrogen compressors used to recover boil-off gas (BOG) are not sized to properly handle the large gaseous hydrogen streams released from the trailers during replenishment. Sizing the compressors to match the instantaneous flow rate would be excessively costly and would prevent them from operating at their most efficient speed for most of the day. [Means for solving the problem]

[0016] In certain embodiments, the present invention enables rapid depressurization and rapid loading of a trailer, while simultaneously recovering gaseous hydrogen from the trailer. In certain embodiments, the present invention allows the gaseous hydrogen from the trailer to be transferred to a large container (or group of containers) capable of storing gaseous hydrogen. This storage volume allows the hydrogen gas to be removed from the trailer as soon as it is generated. Next, liquid hydrogen is transferred at a high flow rate (approximately 75 kg / min) using a pump. In certain embodiments, gaseous hydrogen from the trailer compresses the liquid hydrogen storage container, thereby providing NPSH (Non-Pressurized Hydrogen Shutter) that allows the pump to transfer the liquid hydrogen at a high flow rate. The gaseous hydrogen in the storage container increases the pressure inside the container, and this pressure can be controlled by exhausting, compressing the gas to a higher pressure, or liquefying the gaseous hydrogen into liquid hydrogen.

[0017] In certain embodiments, the present invention may use an existing liquid hydrogen storage container as a pseudo-buffer tank for gaseous hydrogen escaping from a trailer during replenishment. In alternative embodiments, another gaseous hydrogen storage tank may also be used, but this is less desirable from a CAPEX standpoint. In addition, this alternative embodiment also increases operating costs (OPEX) because it does not serve to its advantage in accumulating head pressure in the liquid hydrogen storage tank during replenishment.

[0018] In certain embodiments, gaseous hydrogen may be temporarily stored in a liquid hydrogen storage tank during replenishment and then recycled to the liquefaction's feed section using a typical low-pressure boil-off gas (BOG) compressor. Hydrogen gas from the trailer may be removed from the trailer as soon as the gas is produced. Meanwhile, the compressor only needs to be sized to match the average flow rate of gas removal, as the liquid hydrogen storage tank acts as a buffer for instantaneous flow rates. This compressor sizing method allows the compressor to be much smaller than the one required for the instantaneous flow rate of hydrogen gas that needs to be removed from the liquid hydrogen trailer.

[0019] In other embodiments, gaseous hydrogen can be condensed in a liquid hydrogen storage tank using subcooled liquid hydrogen from a liquefaction unit or by providing a condenser in the headspace. In certain embodiments, the coolant flowing through the condenser may include helium.

[0020] In other embodiments, a series of parallel bullet tanks may be used instead of a single large spherical liquid hydrogen tank. Each tank has a smaller volume than a single spherical storage tank, which means that its pressure can be increased more easily (i.e., smaller liquid hydrogen tanks will make a greater difference for the same amount of gaseous hydrogen from the transport tank).

[0021] In other words, certain embodiments of the present invention provide the benefit of recovering even more gaseous hydrogen molecules, recovering the frigory of gaseous hydrogen molecules, and improving the filling time (for example, by four times in some cases).

[0022] In certain embodiments of the present invention, a method for filling a hydrogen transport trailer is provided. In this embodiment, the method includes transferring liquid hydrogen from a liquid hydrogen storage container to the hydrogen transport trailer via a liquid transfer line, and sending gaseous hydrogen from the gas headspace of the hydrogen transport trailer to the liquid hydrogen storage container via a gas transfer line, wherein the liquid hydrogen storage container is configured to be in fluid communication with a hydrogen liquefaction device, whereby the liquid hydrogen storage container is configured to receive liquid hydrogen from the hydrogen liquefaction device.

[0023] In an optional embodiment of the method for filling a hydrogen transport trailer, · The method may further include c) processing the gaseous hydrogen in the liquid hydrogen storage container. · Step c) includes sending the gaseous hydrogen to the hydrogen liquefaction device for liquefaction therein. · Step c) further includes liquefying the gaseous hydrogen in the liquid hydrogen storage container. · The gaseous hydrogen is liquefied using cooling provided by a cooling cycle having a coolant. · The cooling is performed within the headspace of the liquid hydrogen storage container or outside the liquid hydrogen storage container. · The coolant is configured to provide cooling to 20K - 22K. · The coolant is selected from the group consisting of helium, hydrogen, neon, and combinations thereof. · The gaseous hydrogen is liquefied by introducing a subcooled liquid hydrogen stream through the headspace, thereby providing direct contact with the gaseous hydrogen. · The subcooled liquid hydrogen stream is introduced using a spray header. · The gaseous hydrogen is liquefied by indirect heat exchange through an upper condenser cooled using a coolant. · The coolant is configured to provide cooling to 20K - 22K. · The coolant is selected from the group consisting of helium, hydrogen, neon, and combinations thereof. · The gaseous hydrogen is liquefied by sending the gaseous hydrogen as boil-off gas from the liquid hydrogen storage container to the hydrogen liquefaction device. Step 0 involves the use of a liquid pump placed on the liquid transfer line. • Liquid hydrogen storage containers include spherical tanks. • The liquid hydrogen storage container includes multiple bullet tanks. Step a) is ○A step of selecting a first bullet tank having the highest gas phase pressure among several bullet tanks, ○The first step is to equalize the gas phase pressure between the bullet tank and the hydrogen transport trailer, ○The step of pressurizing liquid hydrogen from the first bullet tank to the hydrogen transport trailer until the hydrogen transport trailer reaches a predetermined value. It also includes. The method is, ○A step of stopping the fluid communication between the first bullet tank and the hydrogen transport trailer, ○A step of selecting a second bullet tank having the second highest gas phase pressure among multiple bullet tanks, ○The step of equalizing the gas phase pressure between the second bullet tank and the hydrogen transport trailer, ○The step of pressurizing liquid hydrogen from the second bullet tank to the hydrogen transport trailer until the hydrogen transport trailer reaches a second predetermined value, and This may further include: The method may further include step c) processing gaseous hydrogen in a liquid hydrogen storage container, step c) further including sending the gaseous hydrogen from a plurality of bullet tanks to a hydrogen liquefaction unit for liquefaction therein.

[0024] These and other features, aspects and advantages of the present invention will be better understood with reference to the following description, claims and accompanying drawings. However, the drawings are merely illustrative of some embodiments of the present invention and, therefore, other equally effective embodiments are also achievable and should not be considered limiting to the scope of the invention. [Brief explanation of the drawing]

[0025] [Figure 1] Figure 1 shows an embodiment of the present invention. [Figure 2] Figure 2 shows a second embodiment of the present invention. [Figure 3] Figure 3 shows a third embodiment of the present invention. [Figure 4] Figure 4 shows an embodiment of the prior art. [Figure 5] Figure 5 shows a fourth embodiment of the present invention. [Figure 6] Figure 6 shows a fifth embodiment of the present invention. [Figure 7] Figure 7 shows a sixth embodiment of the present invention. [Modes for carrying out the invention]

[0026] While the present invention will be described in relation to several embodiments, it should be understood that the invention is not intended to be limited to these embodiments. On the contrary, it is intended to encompass all alternative forms, improvements, and equivalents that may fall within the spirit and scope of the invention as defined by the accompanying claims.

[0027] Embodiments of the present invention, though not in any particular order, 1) To store gaseous hydrogen returning from the trailer. 2) Liquefying gaseous hydrogen into liquid hydrogen, and 3) Increase the flow rate of liquid hydrogen to the trailer. The goal is to achieve this.

[0028] Storage of gaseous hydrogen Gaseous hydrogen is present in the trailer when it returns to the liquefaction unit, and it is generated when heat enters the system. Furthermore, small amounts of gaseous hydrogen are constantly generated in the liquid hydrogen storage container. When the trailer depressurizes, a large amount of gaseous hydrogen (up to 200 kg) needs to be removed from the trailer. To remove the gaseous hydrogen quickly, plants often vent it into the atmosphere, as recovering it from the trailer is a time-consuming process. A substantial amount of gaseous hydrogen also needs to be removed from the trailer during loading, and this gaseous hydrogen presents the same dilemma.

[0029] Exhaust can be reduced by providing a dedicated low-pressure storage unit for this hydrogen exhausted by other means, which can accommodate high instantaneous flow rates of gaseous hydrogen and thus process the hydrogen over longer periods. However, this solution requires a larger footprint, increases CAPEX (due to the extra storage container), and has the problem of not being able to recover any frigory from the gaseous hydrogen.

[0030] In the first embodiment, gaseous hydrogen can be recovered into the headspace of an existing cryogenic liquid hydrogen storage container. The gas line for this purpose is preferably insulated throughout the system to ensure that little heat returns to the liquid hydrogen storage container. In this process, the molecules and cooling force of gaseous hydrogen are recovered.

[0031] This embodiment has the advantage of reducing CAPEX expenditures compared to existing solutions by using existing liquid hydrogen storage containers. In addition, the headspace of existing liquid hydrogen storage containers typically has substantial volume, thus providing the ability to handle large flows from arriving trailers. Furthermore, the headspace of liquid hydrogen storage containers is cold, and therefore it keeps gaseous hydrogen in its cold state, and the volume required for this is much smaller than when storing gaseous hydrogen at room temperature. Finally, the gaseous hydrogen interacts with the liquid hydrogen to form a new equilibrium state, resulting in the condensation of some of the gaseous hydrogen, thereby reducing the pressure.

[0032] In an alternative embodiment of the present invention, The recovered gaseous hydrogen enters the top or bottom of the liquid hydrogen storage container, allowing for better control of the pressure within the liquid hydrogen storage container. In the case of multiple liquid hydrogen storage containers, gaseous hydrogen may also be directed to the top or bottom of a liquid hydrogen storage container separate from the one supplying liquid hydrogen to the trailer.

[0033] Conversion to liquid hydrogen After storing gaseous hydrogen from a trailer into a liquid hydrogen storage container, the gaseous hydrogen can be liquefied. In addition to the gaseous hydrogen recovered from the trailer, the liquid hydrogen storage container generates a continuous boil-off of gaseous hydrogen, which also needs to be liquefied. When the gaseous hydrogen is in the storage container, liquefaction can be carried out at a steady flow rate (steady flow rate = average flow rate instead of instantaneous flow rate from the trailer). Delivering gaseous hydrogen to the liquefaction process at a constant flow rate is much easier for the control unit of the liquefaction process to manage.

[0034] In certain embodiments, gaseous hydrogen can be converted to liquid hydrogen by compressing low-pressure gaseous hydrogen (about 5 psig) to high pressure (>300 psig) and injecting it into the gaseous hydrogen supply circuit of a liquefaction device, where it is liquefied into liquid hydrogen. While this process is sufficient, it also has the following problems. • Compressor CAPEX • Compressor OPEX • Low reliability of rotating machinery • Increased maintenance work on rotating machinery • Process complexity

[0035] Hydrogen is typically liquefied by a nitrogen cooling loop that cools the hydrogen to 80 K, and either a hydrogen cooling loop or a helium cooling loop that cools the hydrogen to 25 K. The hydrogen product is introduced into the liquefaction unit at high pressure (approximately 300 psig), and the hydrogen product is maintained at high pressure during the cooling step. After the final cooling step, the hydrogen is expanded through a valve or turbine to reach the final state of liquid hydrogen at low pressure (approximately 10 psig). Specific embodiments of the present invention seek to utilize at least some of this existing infrastructure to liquefy low-pressure gaseous hydrogen from a trailer.

[0036] In another embodiment shown in Figure 1, subcooled liquid hydrogen 2 may be introduced through a spray header 10, thereby improving contact between the subcooled droplets 12 and the gaseous hydrogen 15 in the headspace of the storage tank 20. The cooler liquid hydrogen interacts with the gaseous hydrogen, condensing some of it. This process directly liquefies the gaseous hydrogen into liquid hydrogen 25 within the storage spherical tank. This embodiment is advantageous because it does not require dedicated equipment such as a compressor or flash drum. Furthermore, this embodiment allows for the miniaturization and simplification of many, if not all, heat exchangers because there is no need for a path for the gaseous hydrogen to move from the cooler side to the hotter side of the process.

[0037] In one embodiment, a solution for liquefying cryogenic gaseous hydrogen is to condense the gaseous hydrogen into liquid hydrogen within an existing liquid hydrogen storage container. This can be achieved, for example, by condensing the gaseous hydrogen into liquid hydrogen through the use of a cryogenic cooling cycle. As shown in Figure 2, gaseous hydrogen from the headspace 15 may be drawn through conduit 34 and then introduced into a heat exchanger 230, where it is liquefied in action with a coolant flowing through conduits 228 and 232. The liquefied hydrogen 234 can then be returned to the liquid hydrogen storage container 20.

[0038] In an optional embodiment, gaseous hydrogen can be supplied to the hydrogen liquefaction unit using a gas extraction line 36. Since this flow rate can be controlled separately from the filling of the transport trailer, this embodiment provides greater flexibility when handling large gas flows, and in either case, there is no need to add significant equipment (i.e., extra compressors, heat exchangers, etc.) to the hydrogen liquefaction unit.

[0039] In certain embodiments, the coolant used as part of the cooling cycle may include one or more helium, neon, and hydrogen.

[0040] In another embodiment shown in Figure 3, the condenser 30 may be provided within the headspace 15 of the liquid hydrogen storage container 20. The condenser is filled with a cryogenic liquid coolant 28 (preferably about 21K) and, as the coolant condenses gaseous hydrogen and absorbs heat, the coolant vaporizes and returns to its cooling cycle 32. In certain embodiments, the coolant may include one or more of helium, neon, and hydrogen.

[0041] The advantages of this embodiment include the following: • The hydrogen cooling cycle already includes a coolant compressor with low suction pressure. • By not introducing more flow into the 20K cold box, the process is simplified. • Because the pressure inside the spherical tank can be increased to store additional gaseous hydrogen, it is not necessary to liquefy the gaseous hydrogen at its instantaneous flow rate.

[0042] Increased flow rate of liquid hydrogen to the trailer Liquid hydrogen flows from a liquid hydrogen storage tank 20 (e.g., a spherical tank) to a trailer 40 via a pressure gradient. This pressure gradient and the (constant) characteristic resistance of the piping system determine the flow rate of liquid hydrogen to the trailer. Typically, the pressure gradient is provided by either maintaining the spherical tank at a higher pressure to exhaust the gas 41 in the trailer 40 into the atmosphere, or by recovering the gas at the suction of a low-pressure compressor.

[0043] For example, the pressure in a spherical tank may be approximately 10 psig, and the pressure in the trailer is approximately 5 psig. When hydrogen gas is exhausted into the atmosphere, atmospheric pressure is 0 psig, which allows liquid hydrogen to flow into the trailer at approximately 20 kg / min. When gaseous hydrogen is sent to a low-pressure compressor, its pressure is approximately 6 psig, which significantly reduces the flow of liquid hydrogen into the trailer to approximately 10 kg / min. The pressure gradient during trailer filling in this example is shown in Figure 4.

[0044] Figure 5 shows an alternative embodiment of Figure 4, but the embodiment shown in Figure 5 is still not ideal because the pressure gradient is still too small, resulting in a low flow rate of liquid hydrogen. For example, assuming the same characteristic resistance of the circuit, the flow rate is <5 kg / min, which results in a longer loading time for the trailer.

[0045] Figure 6 provides a solution to mitigate this problem. For example, a liquid pump 50 can be provided between the spherical tank 20 and the trailer 40 to compress the liquid hydrogen 26 from the spherical tank to a higher pressure (e.g., 20 psig). This can provide an acceptable pressure gradient for forcing gaseous hydrogen 42 from the trailer into the headspace 15 of the spherical tank 20, thereby increasing the overall flow rate of liquid hydrogen to the trailer 40. For example, the flow rate for trailer loading can easily be 60+ kg / min in this configuration, thereby reducing the loading time to approximately 33% of the current loading time.

[0046] centrifugal pump The number of industrial liquid hydrogen centrifugal pumps proven reliable for handling hydrogen is limited. Furthermore, no liquid hydrogen centrifugal pump is currently designed to operate at the extremely low effective suction head (NPSH) (<5 psi) required for liquid hydrogen storage containers.

[0047] A minimum level of NPSH is required to pump the liquid. Current liquid hydrogen pumps are designed for a minimum available NPSHa of 5 psi with a large margin, and therefore simply adding a liquid pump to the embodiment in Figure 5 would not suffice.

[0048] Accordingly, embodiments of the present invention overcome the NPSHa problem by directing gaseous hydrogen from the trailer into an existing liquid hydrogen storage container (e.g., a spherical or bullet tank). By managing the trailer loading process through specific control of gaseous hydrogen within the trailer, the pressure in the liquid hydrogen storage container increases, which provides sufficient NPSH for the liquid hydrogen centrifugal pump.

[0049] Storage of liquid hydrogen Liquefaction plants require large on-site storage facilities to maintain inventory in case of downtime (e.g., maintenance activities, high utility costs). These storage facilities typically consist of one large spherical container or multiple bullet containers. Bullet containers are horizontal or vertical storage containers that can be transported from the manufacturing site to the location of the liquefaction plant. Large spherical liquefied hydrogen storage containers must be constructed on-site, which is very time-consuming and costly. Due to the advantages of bullet tanks, liquefaction plant suppliers often provide bullet tanks for liquid hydrogen storage.

[0050] Separately, while Figures 1-6 all illustrate the use of spherical liquid hydrogen tanks, those skilled in the art will see that the embodiments shown in these figures should not be limited to large spherical tanks. Rather, multiple bullet tanks can also be used in the embodiments shown in Figures 1-6, and especially in Figure 2.

[0051] For example, in another embodiment of the present invention, the solution may also include a storage location using multiple bullet tanks, since the proportion of the volume in the trailer is closer to the volume of a single bullet tank. As shown in Figure 7, separate valves may be used on the gas side 75 and the liquid hydrogen side 70 of each bullet tank 80A, 80B, 80C, thereby allowing the filling bay to access the gas phase and liquid phase of any individual bullet tank.

[0052] In embodiments that incorporate a group of bullet tanks, the following steps may be used: • Before loading onto the trailer, a step to equalize the gas phase between the bullet tank and the trailer. • The step of pressurizing the ammunition from the ammunition tank into the trailer until the trailer is full. - The step of connecting the trailer's gas space to the second highest pressure liquid hydrogen storage container (if there are multiple liquid hydrogen storage containers), The step continues until the gas space of the trailer is opened to the gas space of the liquid hydrogen container with the lowest pressure (if there are multiple liquid hydrogen storage containers). The step of removing gaseous hydrogen from each bullet tank by liquefying the low-pressure gaseous hydrogen in the liquid hydrogen storage container (Solutions 2 and 3), removing the gaseous hydrogen with a compressor, or exhausting the gaseous hydrogen, thereby returning the bullet tank to its original low pressure.

[0053] By using the embodiments shown in Figures 5 and 6, the centrifugal pump can be made operational by supplying the necessary NPSH to the pump. In additional embodiments, the bullet tank equipment may have the following alternative configurations: • The bullet tanks can be installed at different heights. The lowest container always has more liquid hydrogen and less gas space, which provides better conditions for accumulating NPSHA for the pump. After the vapor is recovered, all bullet tanks can be made equal, or the vapor can be removed from individual bullet tanks. The solution can also be used with circular tanks, but in this case, the impact on NPSH is smaller. • Connect one trailer directly to one ammunition tank (see Attachment 2 for steps).

[0054] As discussed herein, embodiments of the present invention advantageously enable the provision of NPSH for 1) storing gaseous hydrogen, 2) liquefying gaseous hydrogen at low pressure, and 3) enabling pumping via existing centrifugal pumps. The resulting overall advantages include lower CAPEX (fewer filling bays, no need for extra gas compressors, no need for dedicated gas storage containers), recovery of gaseous hydrogen molecules (improved efficiency), faster filling of liquid hydrogen trailers, and simplified plant / process design.

[0055] While the present invention has been described in relation to its specific embodiments, it will be apparent to those skilled in the art that many alternative, improved, and modified forms are readily apparent from the above description. Therefore, all such alternative, improved, and modified forms are intended to be encompassed within the spirit and broad scope of the accompanying patent. The present invention may appropriately include, consist of, or essentially consist of the disclosed elements, and may be implemented without any undisclosed elements. Furthermore, where there are sequential terms such as "first," "second," etc., these should be understood as illustrative, not restrictive. For example, those skilled in the art will see that certain steps can be combined into a single step.

[0056] The singular articles "a," "an," and "that" also include plural forms unless the context clearly requires a different interpretation.

[0057] Within the scope of a patent, “contains” is an open transitional clause meaning that the claim elements that follow it are a non-exclusive list (i.e., any additional elements may also be included within the scope of “contains”). As used herein, “contains” may be replaced with the more restrictive transitional clauses “essentially from” and “consist of” unless otherwise explicitly stated.

[0058] In a claim, “to provide” is defined as meaning to equip, supply, make available or prepare something. The step may be performed by any actor unless there is explicit language to the contrary in the claim.

[0059] "Optional" or "optional" means that the event or situation described thereafter may or may not occur. The description includes both cases in which the event or situation occurs and cases in which it does not.

[0060] In this specification, a range may be expressed as a range from about one specific value and / or about another specific value. Where such a range is expressed, other embodiments should be understood to be from that specific value and / or to another specific value, and to include any combination within the said range.

Claims

1. A method for filling a hydrogen transport trailer (40), a) A step of transferring liquid hydrogen (25) from liquid hydrogen storage containers (20, 80) to the hydrogen transport trailer (40) via a liquid transfer line (26), b) The step of transporting gaseous hydrogen from the gas head space (15) of the hydrogen transport trailer (40) to the liquid hydrogen storage containers (20, 80) via a gas transfer line (42); A method comprising the liquid hydrogen storage containers (20, 80) being configured to be in fluid communication with a hydrogen liquefaction device, thereby configuring the liquid hydrogen storage containers (20, 80) to receive liquid hydrogen from the hydrogen liquefaction device.

2. c) The method according to claim 1, further comprising the step of treating the gaseous hydrogen in the liquid hydrogen storage container (20, 80).

3. The method according to claim 2, wherein step c) includes sending the gaseous hydrogen to the hydrogen liquefaction apparatus for liquefaction therein.

4. The method according to claim 3, wherein the gaseous hydrogen is liquefied by sending the gaseous hydrogen to the hydrogen liquefaction device as a boil-off gas from the liquid hydrogen storage containers (20, 80).

5. The method according to claim 2, further comprising step c) liquefying the gaseous hydrogen in the liquid hydrogen storage container (20, 80).

6. The method according to claim 5, wherein the gaseous hydrogen is liquefied using cooling provided by a cooling cycle having a coolant.

7. The method according to claim 6, wherein the cooling is performed using an indirect heat exchanger (230) either within the gas headspace (15) of the liquid hydrogen storage container (20, 80) or outside the liquid hydrogen storage container (20, 80).

8. The method according to claim 6, wherein the coolant is configured to provide cooling to 20K to 22K.

9. The method according to claim 6, wherein the coolant is selected from the group consisting of helium, hydrogen, neon, and combinations thereof.

10. The method according to claim 5, wherein the gaseous hydrogen is liquefied by introducing a subcooled liquid hydrogen flow (2) through the gas headspace (15), thereby providing direct contact with the gaseous hydrogen.

11. The method according to claim 10, wherein the subcooled liquid hydrogen stream (2) is introduced using a spray header (10).

12. The method according to claim 5, wherein the gaseous hydrogen is liquefied by indirect heat exchange via an upper condenser (30) that is cooled using a coolant.

13. The method according to claim 12, wherein the coolant is configured to provide cooling to 20K to 22K.

14. The method according to claim 12, wherein the coolant is selected from the group consisting of helium, hydrogen, neon, and combinations thereof.

15. The method according to claim 1, wherein step a) includes using a liquid pump (50) located on the liquid transfer line (26).

16. The method according to claim 1, wherein the liquid hydrogen storage container (20) includes a spherical tank (20).

17. The method according to claim 1, wherein the liquid hydrogen storage container (80) includes a plurality of bullet tanks (80a, 80b, 80c).

18. Step a) is The step of selecting a first bullet tank (80A) having the highest gas phase pressure among the plurality of bullet tanks, The steps include equalizing the gas phase pressure between the first bullet tank (80A) and the hydrogen transport trailer (40), Step (50) of pressurizing liquid hydrogen from the first bullet tank (80A) to the hydrogen transport trailer (40) until the hydrogen transport trailer (40) reaches a predetermined value, The method according to claim 17, further comprising:

19. The steps include stopping the fluid communication between the first bullet tank (80A) and the hydrogen transport trailer (40), The step of selecting a second bullet tank (80B) having the second highest gas phase pressure among the plurality of bullet tanks, The steps include equalizing the gas phase pressure between the second bullet tank (80B) and the hydrogen transport trailer (40), Step (50) of pressurizing liquid hydrogen from the second bullet tank (80B) to the hydrogen transport trailer (40) until the hydrogen transport trailer (40) reaches a second predetermined value, The method according to claim 18, further comprising:

20. The method according to claim 17, further comprising the step of processing the gaseous hydrogen in the liquid hydrogen storage containers (80a, 80b, 80c), the step of sending the gaseous hydrogen from the plurality of bullet tanks (80a, 80b, 80c) to the hydrogen liquefaction apparatus for liquefaction therein.

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