Devices and methods for transferring cryogenic fluids

Abstract

A method and device for transferring a cryogenic fluid, comprising a first reservoir (2) for distributing the cryogenic fluid, a second receiving cryogenic reservoir (3) containing the cryogenic fluid, and a fluid transfer circuit connecting the first reservoir (2) and the second reservoir (3), the transfer circuit including a first pipe (4) connecting upper portions of the first reservoir (2) and the second reservoir (3) and including at least one valve (5), the transfer circuit including a second pipe (6) connecting a lower portion of the first (2) reservoir to the second (3) reservoir. , the second (6) transfer pipe includes a pump (7) having an inlet connected to the first (2) reservoir and an outlet connected to the second (3) reservoir, and a fluid transfer circuit configured such that the pump (7) and at least one valve (5) of the first pipe (4) fluidly connect upper portions of the first reservoir (2) and the second reservoir (3) by opening the at least one valve (5) when liquid is being transferred from the first reservoir (2) to the second reservoir (3) by the pump (7).

Description

Technical Field

[0001] The present invention relates to a device and method for transferring cryogenic fluids in a liquefied gas storage container.

[0002] More specifically, the present invention relates to a device for transferring cryogenic fluids, comprising a first tank for storing a cryogenic fluid for distributing the cryogenic fluid, the first tank having a lower liquid phase and an upper gas phase; a second, receiving cryogenic tank for containing a cryogenic fluid including a lower liquid phase and an upper gas phase; and a fluid transfer circuit connecting the first tank and the second tank, the transfer circuit including a first pipe connecting the upper portions of the first and second tanks and including at least one valve, and the transfer circuit including a second pipe connecting the lower portion of the first tank to the second tank.

Background Art

[0003] To fill a liquid hydrogen tank from a mobile tank (semi-trailer), a system for delivering liquid by means of a pressure difference is commonly used. Typically, the storage container to be filled has a pressure of 1.0 to 13 bara (typically 3 bara), and the liquid contained in the delivery tank has a pressure of 1.0 bara to 13 bara. To achieve this transfer by pressure difference, in most cases, it is first necessary to pressurize the tank of the delivery semi-trailer to a pressure typically 1 barg higher than the pressure of the fixed storage container to be filled.

[0004] Currently, an atmospheric heater is generally placed under the delivery semi-trailer to enable pressurization of its contents and transfer to the receiving tank.

[0005] This system has several drawbacks. Therefore, it is difficult to control its performance because it is related to weather conditions (temperature, wind, humidity). Furthermore, stratification (increase in gas temperature with altitude) caused in the gas headspace of the delivery semi-trailer tends to heat the liquid hydrogen delivered to the consumer (even more so in the case of multiple deliveries). Consequently, the quality of the delivered hydrogen deteriorates. Additionally, the need to pressurize the tanks of the delivery semi-trailer before the start of transport can last from 15 to 60 minutes, depending on the level in the delivery tanks.

[0006] In other known solutions, a pump is used to transfer the liquid from one storage container to the other. However, the use of a pump necessitates the provision of an atmospheric heater to compensate for the volume of liquid leaving the container with gas coming from the heater.

[0007] Furthermore, current transfer pump technology has other drawbacks. Therefore, by pressurizing the liquid, the pump adds heat to the fluid being transferred and can be damaged by cavitation within the cryogenic liquid as the pumped flow rate decreases. Additionally, the flow rate into the customer tank by the pump is quite high. As a result, a considerable amount of gas must be vented to create space for this incoming liquid volume. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The aim of the present invention is to mitigate some or all of the drawbacks of the prior art listed above. [Means for solving the problem]

[0009] For this purpose, the device according to the present invention, as generally defined in the above prerequisites, is characterized in that the second transfer pipe includes a pump having an inlet connected to the first tank and an outlet connected to the second tank, and at least one valve of the pump and the first pipe is configured to open this at least one valve during the transfer of liquid from the first tank to the second tank by the pump, thereby creating fluid communication between the upper portions of the first and second tanks.

[0010] Furthermore, embodiments of the present invention have the following features, namely, - The second pipe includes an end that connects the lower part of the first tank to the lower part of the second tank, - The second pipe includes an end that connects the lower part of the first tank to the upper part of the second tank, - The second tank includes a system for pressurizing the tank, which includes a pipe connecting the lower and upper parts of the tank and equipped with a heater and a set of one or more valves. It may have one or more of these.

[0011] The present invention also relates to a method for transferring a cryogenic fluid between a first tank and a second cryogenic tank for distributing the cryogenic fluid in a device having any one of the above or below features, the method comprising the steps of transferring the liquid from the first tank to the second tank by pumping, and simultaneously opening at least one valve of the first pipe to fluidize the upper portions of the first and second tanks.

[0012] According to other possible specific characteristics, - During the step of transferring the liquid from the first tank to the second tank by a pump, the liquid is transferred into the lower liquid section and / or into the upper gas section of the second tank. - The method includes a step of equalizing the pressure between two cryogenic tanks before the step of transferring the liquid, during which only the upper portions of the first and second tanks are fluidly connected by opening at least one valve of the first pipe. - The pressure equalization step is maintained until the pressure difference between the two tanks reaches a predetermined threshold, for example, 0-1 bar. - The method includes the step of transferring liquid from a first tank to a second tank using a pump, and simultaneously pressurizing the second tank and / or the first tank. - The pressurization step is carried out by a system for pressurizing the second tank or the first tank, which includes a pipe connecting the lower and upper portions of the tank and equipped with one or more sets of valves and a heater.

[0013] The present invention may also relate to any alternative device or method that includes any combination of the above or below features within the scope of the claims.

[0014] Further specific features and advantages will become clear upon reading the following description, which is provided with reference to the drawings. [Brief explanation of the drawing]

[0015] [Figure 1] A schematic sub-diagram illustrating the structure and operation of an example of a device according to the present invention in a first possible use step is shown. [Figure 2] Shows the same device in a different operating configuration. [Figure 3] Shows the same device in a different operating configuration. [Figure 4] This diagram shows a schematic sub-diagram illustrating the structure and operation of another possible example of the device according to the present invention. [Modes for carrying out the invention]

[0016] A device 1 for transferring cryogenic fluids includes a first tank 2 for distributing the cryogenic fluid, for example, a mobile tank 2 attached to a semi-trailer. Conventionally, the first tank 2 stores a cryogenic fluid, such as hydrogen, with the liquid phase in the lower part and the gas phase in the upper part.

[0017] Device 1 includes a second cryogenic tank 3 for receiving the same fluid, which is, for example, fixed and is intended to contain or be capable of containing a cryogenic fluid with the liquid phase in the lower part and the gas phase in the upper part. Device 1 includes a fluid transfer circuit that can connect the first tank 2 and the second tank 3. This transfer circuit includes a first pipe 4 having two ends respectively connected to the upper parts of the first tank 2 and the second tank 3. This first pipe 4 includes at least one valve 5 (and, for example, preferably at least two valves in series) and has one end connected to the second tank 3, and includes a removable connection member to enable continuous connection to various tanks that can be supplied with fluid.

[0018] The transfer circuit includes a second pipe 6 that can connect the lower part of the first tank 2 to the second tank 3 (in the upper and / or lower parts). In the illustrated example, the second pipe 6 includes two downstream ends respectively connected to the lower part and the upper part of the second tank 3. The second transfer pipe 6 includes a pump 7 that includes an inlet connected to the first tank 2 and an outlet connected to the second tank 3. This second pipe 6 includes a set of preferably one or more valves for interrupting or permitting the transfer of fluid flow from the first tank 2 to the second tank 3. As described above, at at least one or more of its downstream ends connected to the second tank 3, the second pipe 6 includes a removable connection member to enable continuous connection to various tanks that will be supplied.

[0019] As will be described in more detail below, the set of one or more valves 5 of the pump 7 and the first pipe 4 are configured to fluidly connect the upper parts (gas phases) of the first tank 2 and the second tank 3 during the transfer of liquid from the first tank 2 to the second tank 3 by the pump 7.

[0020] During pumping, connecting the gas head spaces of the two tanks 2 and 3 improves the heat and hydraulic efficiency of fluid transfer in an optimal sequential procedure. This makes the use of the atmospheric heater in the first tank 2 optional, improves the quality of the delivered molecules and the volumetric efficiency of delivery, and at the same time enables beneficial use of the gas head space of the second tank 3.

[0021] Therefore, while the pump 7 circulates the liquid from the first tank 2 to the second tank 3, the second pipe 6 allows the "surplus" gas present in the second tank 3 to circulate into the first tank 2 due to the pressure difference, especially to fill the volume emptied by the liquid draw.

[0022] Examples of use are described below.

[0023] For example, in the case of delivering a liquefied gas such as hydrogen, the first tank 2 can reach a location where the second tank 3 is. The first tank 2 has an internal pressure of, for example, 1 to 6 bara. The operator can connect the two tanks 2 and 3 using the first pipe 4 and the second pipe 6. When making this connection, the valve set is closed.

[0024] Preferably, the operations of inactivation and / or flushing and / or cooling of the pipes 4 and 6 are then carried out.

[0025] One or more valves 5 of the first pipe 4 are opened. The pressure equalizes between the two tanks 2 and 3 (see [Figure 1]).

[0026] Preferably, when the pressure difference between the two tanks 2 and 3 drops close to 0 bar (or a defined value, for example, less than 1 bar), the pump 7 can then be started.

[0027] This makes it possible to utilize the pressure in the second tank 3 to increase the pressure at the pump inlet and optimize the NPSH (inlet pressure drop) of the pump 7.

[0028] The point at which the pressure is equalized between the two tanks 2 and 3 is an intermediate pressure between the two initial pressures in the two tanks 2 and 3, typically 2 to 8 bar. This equalization pressure depends in particular on the initial pressures in the two tanks 2 and 3, their liquid levels, and their respective volumes. The first tank 2 generally has a pressure slightly lower than the pressure in the second tank 3. The pump can then be started, and the corresponding valves are opened to transfer the liquid (see Figure 2).

[0029] The pump 7 is preferably configured to compensate for pressure drops in the liquid line (second pipe 6) and the gas line (first pipe 4). In particular, the first pipe 4 may be thermally insulated to reduce pressure drops.

[0030] If the NPSH of pump 7 becomes insufficient during transfer, an atmospheric heater located, for example, at the location of the second tank 3 (see Figure 3) (or at the first tank 2 or both simultaneously) can be optionally used to pressurize the gas headspace of the two tanks 2 and 3 connected by fluid communication.

[0031] For example, the second tank 3 is a pressurizing system 8 which includes a pipe connecting the lower and upper parts of the tank and equipped with one or more sets of valves and an atmospheric heater (for heating the heat exchanger).

[0032] Pump 7 is preferably a single-stage or multi-stage centrifugal separator type pump of a specific speed selected to increase isentropic efficiency for relatively small pressure differences. It can preferably be installed in the location of the first tank 2 or the second tank 3 in a thermally insulated container, or it can be directly integrated into the internal structure of the thermally insulated tanks 2 and 3. Its power is preferably less than 10 kW.

[0033] For example, pump 7 may be a pump partially immersed in the cryogenic liquid pumped in a refrigerated container (the pump motor is outside the refrigerated container) or a pump completely insulated (vacuum-insulated) in the refrigerated container. For example, pump 7 may be immersed in a fluid reserve (wastewater tank), i.e., in a relatively small dedicated intermediate liquid tank (e.g., of the cryogenic holding type). Similarly, pump 7 may be directly immersed (at least partially) in one of the two tanks 2, 3 mentioned above (in this case, the pump is at least partially integrated with the tank). Any other arbitrary arrangement configuration of one or more pumps can also be considered.

[0034] Therefore, although it is inexpensive and simple in structure, the present invention offers numerous advantages.

[0035] Therefore, since the evaporated gas from the second tank 3 is used in addition to the transfer pump 7, the introduction of heat into the system is minimized. Pump 7 provides only a small pressure difference (a few bar). Evaporation (evaporation loss) losses are therefore minimized in the logistics chain. The gas headspace of the second tank 3 is used beneficially. This gas is not vented.

[0036] Furthermore, the quality of the delivered molecules improves (at lower delivery temperatures). Multiple deliveries in a single transport tank are more efficient. The solution does not require the consumption of liquid for pressurization. In addition, the immobilization time is reduced because the pressurization time is reduced.

[0037] The solution allows for potential increases in the transfer flow rate while simultaneously maintaining relatively stable pumping conditions. Furthermore, the transfer flow rate is independent of weather conditions. The solution substantially reduces or eliminates cryogenic clouds and condensation of liquid oxygen under the mobile delivery tank 2.

[0038] Furthermore, the procedures for delivery operators are simplified.

[0039] The two tanks 2 and 3 operate at relatively lower pressures, which potentially allows for a reduction in the machine's size limitations (reducing weight, materials, cooling time, and cost).

[0040] It is no longer necessary to equip the first tank 2 with an atmospheric heater, or the dimensions of the atmospheric heater can be significantly reduced.

[0041] In particular, the conditions at the compressor inlet (especially temperature) are far more variable at the pump inlet, so the power consumption of the liquid transfer pump 7 is significantly less than that of a gas compressor that may be used in the pipe 4 connecting the two gas headspaces.

[0042] In the embodiment shown in Figure 4, the device 1 includes a third pipe 9 that connects the first pipe 4 to the lower part of the first tank 2. This third pipe 9 may be part of the transfer circuit and / or belong to the first tank 2.

[0043] As shown in the figure, the third pipe 9 is preferably provided with a valve 19, such as a shut-off valve, which, when in the open position, allows the gaseous upper portion of the second tank 3 to be reduced in pressure into the liquid phase of the first tank 2. That is, the third pipe 9 can allow steam from the second tank 3 to be recovered (and condensed) into the liquid phase of the first tank 2 (via the first line 4).

[0044] After such pressure equalization, the liquid can be drawn from the first tank 2 through the second line 6 (and pump 7).

[0045] This can cause heating of the liquid phase in the first tank 2, but in some applications, this may be expected and even advantageous (for example, at a pressure of 5 bar). The following is a direct reproduction of the claims as originally filed. [1] A first tank (2) for distributing cryogenic fluid, wherein the first tank (2) is a first tank (2) for storing cryogenic fluid having a lower liquid phase and an upper gas phase, a second receiving cryogenic tank (3) for containing cryogenic fluid including a lower liquid phase and an upper gas phase, and a fluid transfer circuit connecting the first tank (2) and the second tank (3), wherein the transfer circuit includes a first pipe (4) which connects the upper portions of the first tank (2) and the second tank (3) and includes at least one valve (5), and the transfer circuit is the first tank The lower portion of tank (2) includes a second pipe (6) connecting to the second tank (3), the second transfer pipe (6) includes a pump (7) having an inlet connected to the first tank (2) and an outlet connected to the second tank (3), and the pump (7) and the at least one valve (5) of the first pipe (4) are configured to open the at least one valve (5) during the transfer of liquid from the first tank (2) to the second tank (3) by the pump (7), thereby creating fluid communication between the upper portions of the first tank (2) and the second tank (3). A method for transferring cryogenic fluid using a device for transferring cryogenic fluid, the method comprising ensuring the transfer of cryogenic fluid between a first tank (2) and a second cryogenic tank for distributing the cryogenic fluid, the method comprising the steps of transferring liquid from the first tank (2) to the second tank (3) by pump (7) and simultaneously opening at least one valve (5) of the first pipe (4) to create fluid communication between the upper portions of the first tank (2) and the second tank (3), wherein This includes a step of equalizing the pressure between the two cryogenic tanks (2, 3) prior to the step of transferring the liquid, during which only the upper portions of the first tank (2) and the second tank (3) are fluidly connected by opening at least one valve (5) of the first pipe (4), and during the step of transferring the liquid from the first tank (2) to the second tank (3) by the pump (7), the liquid is transferred into the lower liquid portion and / or into the upper gas portion of the second tank (3).A method characterized in that the second pipe (6) includes an end that connects the lower portion of the first tank (2) to the lower portion of the second tank (3), and the second pipe (6) includes an end that connects the lower portion of the first tank (2) to the upper portion of the second tank (3). [2] The method according to [1], characterized in that the pressure equalization step is maintained until the pressure difference between the two tanks (2, 3) reaches a predetermined threshold, for example, 0 to 1 bar. [3] The method according to [1] or [2], characterized in that the step of transferring liquid from the first tank (2) to the second tank (3) by the pump (7) is simultaneously accompanied by the step of pressurizing the second tank (3) and / or the first tank (2). [4] The method according to [3], characterized in that the pressurizing step is carried out by a system (8) for pressurizing the second tank (3) or the first tank (2), which includes a pipe connecting the lower and upper portions of the tank and having a set of one or more valves and a heater. [5] The method according to any one of [1] to [4], characterized in that the second tank (3) includes a system (8) for pressurizing the tank (3), the system including a pipe that connects the lower and upper portions of the tank (3) and is provided with a heater and one or more sets of valves. [6] The method according to any one of [1] to [5], characterized in that, before the step of transferring liquid from the first tank (2) to the second tank (3) by the pump (7), the method includes a step of equalizing the pressure between the upper part of the second (3) tank and the lower part of the first tank (2). [7] A first tank (2) for distributing cryogenic fluid, the first tank (2) is a first tank (2) for storing cryogenic fluid having a lower liquid phase and an upper gas phase, a second receiving cryogenic tank (3) for containing cryogenic fluid including a lower liquid phase and an upper gas phase, and a fluid transfer circuit connecting the first tank (2) and the second tank (3), the transfer circuit including a first pipe (4) which connects the upper portions of the first tank (2) and the second tank (3) and includes at least one valve (5), the transfer circuit including a second pipe (6) which connects the lower portion of the first tank (2) to the second tank (3), and the second transfer pipe (6) is the first tank ( A device for transferring cryogenic fluid, comprising a pump (7) having an inlet connected to (2) and an outlet connected to the second tank (3), wherein the pump (7) and the at least one valve (5) of the first pipe (4) are configured to open the at least one valve (5) during the transfer of liquid from the first tank (2) to the second tank (3) by the pump (7), thereby creating fluid communication between the upper portions of the first tank (2) and the second tank (3), the device further comprising a third pipe (9) connecting the upper end of the second tank (3) to the lower end of the first tank (2), wherein the third pipe (9) includes a valve (19).

Claims

1. A first tank (2) for distributing cryogenic fluid, wherein the first tank (2) stores cryogenic fluid having a lower liquid phase and an upper gas phase, A second cryogenic tank (3) receives and contains a cryogenic fluid comprising a lower liquid phase and an upper gas phase, A fluid transfer circuit connecting the first tank (2) and the second tank (3), wherein the fluid transfer circuit comprises a first pipe (4) connecting the upper portions of the first tank (2) and the second tank (3) and having at least one valve (5), and a second transfer pipe (6) connecting the lower portion of the first tank (2) to the second tank (3), and the second transfer pipe (6) comprises a pump (7) including an inlet connected to the first tank (2) and an outlet connected to the second tank (3), and the pump (7) and the at least one valve (5) of the first pipe (4) are configured to open the at least one valve (5) during the transfer of liquid from the first tank (2) to the second tank (3) by the pump (7), thereby creating fluid communication between the upper portions of the first tank (2) and the second tank (3), A method for transferring cryogenic fluids using a device for transferring cryogenic fluids comprising, The method comprises the steps of ensuring the transfer of cryogenic fluid between the first tank (2) and the second cryogenic tank for distributing cryogenic fluid, and transferring liquid from the first tank (2) to the second tank (3) by the pump (7), and simultaneously opening at least one valve (5) of the first pipe (4) to create fluid communication between the upper portions of the first tank (2) and the second tank (3), The method comprises a step of equalizing the pressure between the first tank (2) and the second tank (3) before the step of transferring the liquid, wherein, during this step, only the upper portions of the first tank (2) and the second tank (3) are connected by opening at least one valve (5) of the first pipe (4), During the step in which the pump (7) transfers the liquid from the first tank (2) to the second tank (3), the liquid is transferred into the lower liquid portion and the upper gas portion of the second tank (3). The second transfer pipe (6) has an end that connects the lower portion of the first tank (2) to the lower portion of the second tank (3), A method characterized in that the second transfer pipe (6) has an end that connects the lower portion of the first tank (2) to the upper portion of the second tank (3).

2. The method according to claim 1, characterized in that the step of equalizing the pressure is maintained until the pressure difference between the first tank (2) and the second tank (3) reaches a predetermined threshold.

3. The method according to claim 2, characterized in that the threshold is 0 to 1 bar.

4. The method according to any one of claims 1 to 3, characterized in that, simultaneously with the step of transferring liquid from the first tank (2) to the second tank (3) by the pump (7), a pressurizing step is provided for pressurizing the second tank (3) and / or the first tank (2).

5. The method according to claim 4, characterized in that the pressurizing step is carried out by a system (8) for pressurizing the second tank (3) or the first tank (2), which connects the lower and upper portions of the second tank (3) or the first tank (2) and comprises a pipe equipped with one or more valve sets and a heater.

6. The method according to any one of claims 1 to 5, characterized in that the second tank (3) is provided with a system (8) for pressurizing the second tank (3), the system (8) comprising a pipe connecting the lower and upper portions of the second tank (3) and equipped with a heater and a set of one or more valves.

7. The method according to any one of claims 1 to 6, characterized in that, before the step of transferring liquid from the first tank (2) to the second tank (3) by the pump (7), the method further comprises a step of equalizing the pressure between the upper part of the second tank (3) and the lower part of the first tank (2).

8. A first tank (2) for distributing cryogenic fluid, wherein the first tank (2) stores cryogenic fluid having a lower liquid phase and an upper gas phase, and a second cryogenic tank (3) receives and contains cryogenic fluid including the lower liquid phase and the upper gas phase, and a fluid transfer circuit connecting the first tank (2) and the second tank (3), wherein the fluid transfer circuit comprises a first pipe (4) which connects the upper portions of the first tank (2) and the second tank (3) and is equipped with at least one valve (5), and the fluid transfer circuit comprises a second transfer pipe (6) which connects the lower portion of the first tank (2) to the second tank (3), and the second transfer pipe (6) connects the lower portion of the first tank (2) to the lower portion of the second tank A device for transferring cryogenic fluid, comprising a pump (7) connected to a portion and an upper portion, and including an inlet connected to the first tank (2) and an outlet connected to the second tank (3), and a fluid transfer circuit configured such that the pump (7) and at least one valve (5) of the first pipe (4) open the at least one valve (5) to create fluid communication between the upper portions of the first tank (2) and the second tank (3) during the transfer of liquid from the first tank (2) to the second tank (3) by the pump (7), wherein the device further comprises a third pipe (9) connecting the upper end of the second tank (3) to the lower end of the first tank (2), and the third pipe (9) comprises a valve (19).

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