Apparatus and method for storing and dispensing cryogenic fluids
By using the pressure and flow control device of the gasification gas recovery pipeline in the low-temperature fluid storage and distribution system, the evaporated gas loss problem when the low-temperature reservoir is connected to the ground pump is solved, and the effective supply and efficient operation of the pump are achieved.
Patent Information
- Application Number
- CN202411815183.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-02-01
- Filing Date
- 2024-12-11
- Publication Date
- 2025-08-01
AI Technical Summary
In a low-temperature fuel station, the connection between the buried cryogenic reservoir and the pump on the ground causes the pump to need to be cooled when starting up and leads to loss of evaporated gas. The traditional reflow method is difficult to supply efficiently when the reservoir is lower than the pump inlet.
The pressure and flow control device in the gasification gas recovery pipeline is adopted to control the internal pressure of the reservoir to be higher than the pump inlet pressure, and the gasified gas is recovered and recirculated through components such as heaters, heat exchangers and compressors to ensure the effective supply of the pump.
Reduces evaporated gas losses, ensures correct supply and operation of the pump, and improves the efficiency of low-temperature fluid storage and distribution.
Smart Images
Figure CN120402793A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an apparatus and method for storing and dispensing cryogenic fluids.
[0002] More particularly, the present invention relates to an apparatus for storing and dispensing a cryogenic fluid, such as liquid hydrogen, the apparatus comprising: a cryogenic reservoir buried underground; a liquid extraction circuit, said liquid extraction circuit comprising an upstream end connected to said reservoir and a downstream end located above ground and designed to be connected to a consumption device, said liquid extraction circuit comprising a cryogenic pump arranged above ground, the apparatus further comprising a vapor gas recovery line for recovering the vapor gas generated inside said cryogenic pump, said vapor gas recovery line having an upstream end connected to said cryogenic pump and a downstream end connected to said reservoir. Background Art
[0003] The space requirement for storing hydrogen is a major issue. One solution is underground storage. However, connecting a buried cryogenic reservoir to a filling pump on the ground poses problems in supplying these pumps during different operating levels / stages of these pumps. Conventionally, supplying liquid to the pump is by gravity, i.e., having a sufficient liquid level in the reservoir so that the liquid can reach the pump inlet correctly. Additionally, in a cryogenic fuel station, the pump needs to be cooled at startup, and the pump causes a portion of its supply to evaporate (vapor gas “boil-off gas or BOG”). This vapor gas is typically returned to the reservoir through a pipe leading to the top of the reservoir. This return occurs naturally when the reservoir is above the pump. In a configuration where the high point of the memory is below the pump inlet, this function becomes more difficult to provide. Summary of the Invention
[0004] An object of the present invention is to overcome all or some of the drawbacks of the above prior art.
[0005] To this end, and also in accordance with the general definition given in the above preamble, the basic feature of the apparatus according to the invention is that said vapor gas recovery line comprises at least one pressure and / or flow control device for controlling the pressure and / or flow rate of the vapor gas returned to said reservoir, said pressure and / or flow control device being configured to control the pressure inside said reservoir at a pressure level higher than the pressure at the inlet of said pump.
[0006] This arrangement makes it possible to ensure the correct supply of the pump in order to ensure the operation of the pump by allowing the vapor gas from the pump to be recovered into the reservoir, thereby reducing the total losses of the station.
[0007] Furthermore, embodiments of the present invention may include one or more of the following features:
[0008] - The pressure and / or flow control device is configured to control the pressure inside the reservoir at a level that is 5 mbar to 500 mbar higher than the pressure at the inlet of the pump;
[0009] - The pressure and / or flow control device includes at least one of the following: a heater, a heat exchanger, and a compressor, such as a cryogenic compressor;
[0010] - The pressure and / or flow control device includes a heating heat exchanger / heating type heat exchanger and a compressor arranged in series;
[0011] - The vaporized gas recovery pipeline includes two independent channels in the heating type heat exchanger, which are respectively located before and after compression in the compressor, so as to heat the vaporized gas before compression and cool the vaporized gas before injecting it into the reservoir;
[0012] - The vaporized gas recovery pipeline includes a bypass pipeline that bypasses the heat exchanger and a component composed of one or more valves. The bypass pipeline and the component are configured such that at least a part of the vaporized gas flow can avoid entering the heat exchanger;
[0013] - The vaporized gas recovery pipeline includes a branch that branches out in a T shape, and the branch is provided with a valve towards the discharge area;
[0014] - The device includes an autonomous pressurization device for pressurizing the reservoir, and the pressurization device is independent of the vaporized gas recovery pipeline and the control device;
[0015] - The present invention also relates to a method for extracting a fluid using a device according to any one of the above or following features, characterized in that the method includes the following steps: pumping a cryogenic liquid from a reservoir via a pump; recovering the vaporized gas generated in the area of the pump; compressing the recovered vaporized gas; and injecting the compressed vaporized gas into the reservoir at a determined pressure.
[0016] According to further possible features:
[0017] - The compression of the recovered vaporized gas is carried out by a cryogenic compressor or a non-cryogenic compressor. In the case of a non-cryogenic compressor, the recovered vaporized gas is heated before compression;
[0018] - The compression of the recovered vaporized gas is carried out by a non-cryogenic compressor, and the method further includes the step of cooling the compressed vaporized gas by heat exchange with the vaporized gas flow upstream of the compressor.
[0019] The present invention may also relate to any alternative device or method falling within the scope of the claims and including any combination of the above or below features. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Further features and advantages will become apparent by reading the following description with reference to the accompanying drawings.
[0021] The present invention will be more clearly understood by reading the following description with reference to the accompanying drawings, which are provided by way of example only, wherein:
[0022] Figure 1 is a vertical cross-sectional schematic view showing an example of the structure and operation of the device according to the present invention. DETAILED DESCRIPTION
[0023] In all the drawings, the same reference numerals refer to the same elements.
[0024] In this detailed description, the following embodiments are examples. Although the description relates to one or more embodiments, this does not mean that these features are only applicable to a single embodiment. The individual features of different embodiments can also be combined and / or interchanged to provide additional embodiments.
[0025] The illustrated device 1 for storing and dispensing cryogenic fluids can be used for, for example, liquid hydrogen. The device includes a liquid extraction circuit 20 and a cryogenic reservoir 11 buried underground. The liquid extraction circuit 20 includes an upstream end connected to the reservoir 11 and a downstream end located above the ground and designed to be connected to a consumption device.
[0026] The extraction circuit 20 includes a cryogenic pump 2 arranged above the ground. The device 1 includes a vaporized gas recovery pipeline 3 for recovering the vaporized gas generated inside the pump 2. The vaporized gas recovery pipeline has an upstream end connected to the pump 2 and a downstream end connected to the reservoir 11. The vaporized gas recovery pipeline 3 includes at least one pressure and / or flow control device for controlling the pressure and / or flow rate of the vaporized gas flowing back to the reservoir 11. The at least one pressure and / or flow control device is configured to control the pressure inside the reservoir 11 at a pressure level higher than the pressure at the inlet of the pump 2.
[0027] The pressure and / or flow control device is preferably configured to control the pressure inside the reservoir 11 to be higher than the pressure at the pump inlet so as to exceed the hydrostatic head between the reservoir and the inlet of the pump 2. For example, the pressure and / or flow control device is configured to control the pressure inside the reservoir at a level 5 mbar to 500 mbar higher than the pressure at the pump inlet, for example, at a level 5 mbar to 500 mbar higher than the pressure at the pump inlet. The pressure and / or flow control device includes at least one of a heater 8, a heat exchanger 7, and a compressor 9 (such as a cryogenic compressor). For reasons of simplicity, Figure 1Three of the aforementioned components are shown in series. Naturally, only one or two of the heater, heat exchanger, and compressor may be provided.
[0028] The pressure and / or flow control device may include, for example, a compressor 9 and a heated heat exchanger 7 in series or consist of a compressor 9 and a heated heat exchanger 7 in series with the compressor.
[0029] The vaporized gas generated by the pump 2 is heated in the heat exchanger 7 and then may be returned to the reservoir 11.
[0030] The reservoir 11 can thus be kept pressurized to provide an effective supply to the pump 2. Accordingly, the pressure of the pump 2 at a relatively higher position is lower than the pressure of the reservoir 11. This low pressure refers to, for example, 10 mbar to 100 mbar, as this is the pressure required to overcome the pressure head / manometric height between the reservoir 11 and the inlet of the pump 2 and the pressure losses in the inlet pipeline. Recycling the vaporized gas of the pump 2 into the reservoir 11 enables compensation for this relative pressure difference.
[0031] This configuration enables the recovery of the vaporized gas generated by the pump 2 at its respective operating stages / phases. When starting up, the pump 2 generates a relatively large amount of vaporized gas. After cooling, during its operation, the pump 2 generates a reduced amount of vaporized gas, for example, due to leakage, heat input, etc.
[0032] These vaporized gases can be collected and returned to the reservoir 11 through the recovery pipeline 3.
[0033] This enables the recovery of all or only a part of the vaporized gas generated during these different operating stages.
[0034] The vaporized gas is collected in the recovery pipeline 3, heated in the heated heat exchanger 7, compressed, and then returned to the reservoir. The compressor 9 enables the circulation of the vaporized gas stream by compressing the vaporized gas to the pressure of the reservoir, for example, to a level of several tens of mbar.
[0035] The compressed vaporized gas can be returned to the heated heat exchanger 7 to be cooled before being reinjected into the reservoir 11.
[0036] If the heated heat exchanger 7 is insufficient to heat the gas before compression (excessive flow rate of the vaporized gas, too low temperature at the inlet, etc.), an additional (heating) heat exchanger 8 may be provided to complete the heating to a determined temperature (ambient temperature or the intake temperature of the compressor).
[0037] The optional heater 8 is shown in dashed lines between the heated heat exchanger 7 and the compressor 9.
[0038] As shown in the figure, a valve 5, such as an isolation valve, can be arranged in series between the pump 2 and the heated heat exchanger 7. Similarly, preferably a valve 5 is provided upstream of the pump 2. A valve 5 can also be provided between the heated heat exchanger 7 and the compressor 9.
[0039] Similarly, a check valve 4 can be provided upstream of the pump 2.
[0040] As shown in the figure, the vaporized gas recovery pipeline can provide two separate channels (preferably with countercurrent flow) in the heated heat exchanger 7, which are located respectively before and after compression in the compressor 9, so as to provide heating of the vaporized gas before compression respectively, and provide cooling before injecting the compressed gas into the reservoir 11.
[0041] As schematically shown, the vaporized gas recovery pipeline 3 can also include a bypass pipeline 13 that bypasses / flows around the heat exchanger and a component composed of one or more valves 23. The bypass pipeline and this component are configured such that at least a part of the vaporized gas flow can avoid entering the heat exchanger 7. For example, the bypass pipeline 13 enables all or part of the compressed vaporized gas flow to avoid entering the heated heat exchanger 7 for the second time. This makes it possible to increase the temperature of the compressed vaporized gas before it flows back to the reservoir 11, so as to stabilize the pressure when the pressure in the reservoir 11 rises too fast.
[0042] As shown in the figure, the vaporized gas recovery pipeline 3 can also include a branch 33 that branches out in a T-shaped form. The branch 33 is provided with a valve facing the discharge area. This branch that branches out in a T-shaped form can be located between the heated heat exchanger 7 and the inlet of the compressor 9.
[0043] The reservoir 11 can include a self-contained pressurizing device 10, which is configured to increase the pressure of the reservoir when needed (by extracting, heating and re-injecting the fluid).
[0044] This recovery and recycling of the vaporized gas makes it possible to keep the reservoir 11 overpressurized relative to the pump 2. This permanently ensures the correct suction / flow of the pump 2. If the recovered vaporized gas is not sufficient to maintain a high enough pressure during the operation of the pump, the pressurizing device 10 can be used to pressurize the reservoir 11.
[0045] Naturally, the present invention is not limited to the above exemplary embodiments. Therefore, for example, the heated heat exchanger 7 and the compressor 9 can be replaced by a cryogenic compressor (which can compress gas at low temperature without preheating).
Claims
1. An apparatus for storing and dispensing cryogenic fluids, such as liquid hydrogen, the apparatus comprising: A cryogenic reservoir (11) buried underground; a liquid extraction circuit (20), the liquid extraction circuit including an upstream end connected to the reservoir (11) and a downstream end located above the ground and designed to be connected to a consumption device, the liquid extraction circuit (20) including a cryogenic pump (2) arranged above the ground, the device (1) further including a vapor recovery pipeline (3) for recovering the vaporized gas generated inside the pump (2), the vapor recovery pipeline having an upstream end connected to the pump (2) and a downstream end connected to the reservoir (11), characterized in that the vapor recovery pipeline (3) includes at least one pressure and / or flow control device for controlling the pressure and / or flow rate of the vaporized gas flowing back to the reservoir (11), the pressure and / or flow control device being configured to control the pressure inside the reservoir (11) at a pressure level higher than the pressure at the inlet of the pump (2).
2. The device according to claim 1, wherein The pressure and / or flow control device is configured to control the pressure inside the reservoir at a level 5 mbar to 500 mbar higher than the pressure at the inlet of the pump (2).
3. The device according to claim 1 or 2, characterized in that The pressure and / or flow control device includes at least one of the following: a heater (8), a heat exchanger (7), and a compressor (9), the compressor being a cryogenic compressor, for example.
4. The device according to claim 3, characterized in that, The pressure and / or flow control device includes a heated heat exchanger (7) and a compressor (9) arranged in series.
5. The device according to claim 4, characterized in that, The vapor recovery pipeline (3) includes two independent channels in the heated heat exchanger (7), the two independent channels being located respectively before and after compression in the compressor (9) so as to heat the vaporized gas before compression and cool the vaporized gas before injecting it into the reservoir (11).
6. The device according to claim 4 or 5, characterized in that, The vapor recovery pipeline (3) includes a bypass line (13) bypassing the heat exchanger and a component composed of one or more valves (23), the bypass line and the component being configured such that at least a part of the vaporized gas flow can avoid entering the heat exchanger (7).
7. The device according to any one of claims 1 to 6, characterized in that The vapor recovery pipeline (3) includes a branch (33) branched out in a T shape, the branch being provided with a valve towards the discharge area.
8. The device according to any one of claims 1 to 7, characterized in that, The device includes an autonomous pressurization device (10) for pressurizing the reservoir, the pressurization device being independent of the vapor recovery pipeline (3) and the pressure and / or flow control device.
9. A method for extracting a fluid using the device according to any one of claims 1 to 8, characterized in that, The method includes the following steps: pumping cryogenic liquid from the reservoir via the pump (2); recovering the vaporized gas generated in the area of the pump (2); compressing the recovered vaporized gas; and injecting the compressed vaporized gas into the reservoir at a determined pressure.
10. The method according to claim 9, wherein The compression of the recovered vaporized gas is carried out by a cryogenic compressor or a non-cryogenic compressor. In the case of a non-cryogenic compressor, the recovered vaporized gas is heated before compression.
11. The method according to claim 10, wherein, The compression of the recovered vaporized gas is carried out by a non-cryogenic compressor, and the method further includes the step of cooling the compressed vaporized gas by heat exchange with the vaporized gas flow upstream of the compressor (9).