A liquid hydrogen multi-stage precooling system and hydrogen refueling station

Abstract

The present invention relates to the technical field of hydrogen refueling stations, and specifically discloses a liquid hydrogen multi-stage precooling system and a hydrogen refueling station thereof, which utilizes the cold released by liquid hydrogen to complete the cooling of high-temperature hydrogen. The liquid hydrogen multi-stage precooling system mainly includes: a liquid hydrogen storage device, a hydrogen inlet, a primary heat exchanger, a direct cooling gas-liquid separator, an indirect cooling gas-liquid separator, a compressor, a liquid circulation pipeline and a gas circulation pipeline. In the present invention, the guidance of high-temperature hydrogen, low-temperature hydrogen and low-temperature liquid hydrogen by the pipeline, the arrangement sequence of the direct cooling gas-liquid separator and the indirect cooling gas-liquid separator, etc. cooperate with each other, ensuring that the heat exchange is thorough when hydrogen and liquid hydrogen are directly mixed, and also ensuring that the high-temperature hydrogen can be cooled to the required temperature. In addition, the cold released by the liquid hydrogen is fully utilized during the cooling process, without introducing equipment such as a condenser, saving the overall power consumption of the liquid hydrogen multi-stage precooling system. At the same time, the hydrogen after the cold is released is also reused, without causing waste of materials.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen refueling stations, and in particular to a liquid hydrogen multi-stage precooling system and a hydrogen refueling station thereof. Background Art

[0002] At present, the pressure level of hydrogen refueling stations built in China is mainly 35MPa. Although hydrogen refueling stations with a pressure level of 70MPa have been built, the overall number is relatively small, and some key technologies are still in the trial research stage. The fuel cell vehicle hydrogenation protocol SAE-J2601 (201612R) issued by the American Society of Automotive Engineers has put forward requirements for the gas temperature at the inlet of the 70MPa hydrogen refueling machine, which usually needs to reach -40℃ or below, which indicates that effective temperature control equipment needs to be set at the inlet of the hydrogen refueling machine in the hydrogen refueling station.

[0003] Conventional hydrogen refueling stations use long-tube trailers as hydrogen sources, and the temperature of the hydrogen coming out is usually at or above room temperature, so a pre-cooling device is needed to cool the hydrogen. The pre-cooling devices commonly used in hydrogen refueling stations mainly include refrigeration units, cooling water pipelines, refrigerant pipelines, heat exchangers, etc. The key component is the heat exchanger, which can realize the heat transfer between high-temperature hydrogen and low-temperature refrigerant.

[0004] For example, the patent with application number 202410554801.6 discloses a rapid precooling system and method for a liquid hydrogen refueling station, which includes a liquid hydrogen filling pipeline, a liquid hydrogen supply tank, a pipe valve subsystem, a liquid hydrogen filling tank, a circulation pipeline, a condenser, a gas-liquid separator, a liquid carbon dioxide tank, a gas storage bottle, a helium pipeline, a high-pressure helium cylinder, a fuel cell, a cryogenic hydrogen pipeline, and a liquid hydrogen storage tank group. The system uses liquid carbon dioxide and cryogenic helium to achieve deep coupling between system replacement operation and precooling operation; after the replacement is completed, the system temperature has dropped below the temperature of liquid carbon dioxide, significantly reducing the precooling time; the cryogenic hydrogen stored in the liquid hydrogen storage tank group is also used to liquefy carbon dioxide to realize the circulation of the carbon dioxide medium, and at the same time, the hydrogen after the release of cold and the hydrogen generated by precooling are transported to the fuel cell for power generation, thereby improving the utilization efficiency of hydrogen.

[0005] Although this type of heat exchange method utilizes the cold released by liquid hydrogen and utilizes the hydrogen after the cold is released, it still introduces condensing equipment such as condensers and cooling media such as carbon dioxide into the overall operation of the cooling system. On the one hand, relying on condensers to cool down cooling media and cooling objects will cause high energy consumption, which does not meet the green development requirements of energy conservation and environmental protection; on the other hand, the introduction of other cooling media such as carbon dioxide can easily lead to cumbersome operations in the cooling medium replenishment link, increasing the workload of construction personnel. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a liquid hydrogen multi-stage pre-cooling system, which utilizes the cold energy generated in the process of liquid hydrogen vaporization into hydrogen to cool the high-temperature hydrogen, and at the same time recycles the hydrogen after releasing the cold energy, thereby reducing the overall energy consumption of the liquid hydrogen multi-stage pre-cooling system and the cooling medium involved in the cooling process is only liquid hydrogen, which reduces the difficulty of subsequent maintenance for construction personnel.

[0007] The present invention is achieved through the following technical solutions:

[0008] A liquid hydrogen multi-stage precooling system, comprising:

[0009] A liquid hydrogen storage device for providing liquid hydrogen; a hydrogen inlet for connecting and introducing hydrogen into a liquid hydrogen multi-stage precooling system; a primary heat exchanger comprising a hot side pipeline and a cold side pipeline, the hot side pipeline being used to introduce the hydrogen, the cold side pipeline being used to introduce the liquid hydrogen, a heat exchange medium being arranged between the hot side pipeline and the cold side pipeline for heat exchange between the liquid hydrogen and the hydrogen, the heat exchange medium being made of materials such as metal, or structures such as conductive sheets; a direct cooling gas-liquid separator comprising a first liquid infusion port, an air inlet pipe, a first air outlet, and a first liquid containing area arranged at the bottom of the direct cooling gas-liquid separator, the air inlet of the air inlet pipe being placed in the first liquid containing area; an indirect cooling gas-liquid separator comprising a second liquid infusion port, a cooling pipe section, a second air outlet, and a second liquid containing area arranged at the bottom of the indirect cooling gas-liquid separator, the main body of the cooling pipe section being placed in the second liquid containing area a compressor for compressing hydrogen to form high-pressure gas; a liquid circulation pipeline for guiding the circulation of the liquid hydrogen or the gas-liquid mixture, comprising a first pipe section connecting the liquid hydrogen storage device and the cold side pipeline, a second pipe section and a third pipe section for diverting the gas-liquid mixture flowing out of the cold side pipeline, and respectively connected to the first liquid infusion port and the second liquid infusion port to guide the liquid hydrogen in the gas-liquid mixture to flow into the first liquid containing area and the second liquid containing area respectively; a gas circulation pipeline for guiding the circulation of the hydrogen, comprising a fourth pipe section connecting the hydrogen inlet and the hot side pipeline; a fifth pipe section connecting the hot side pipeline and the gas inlet pipe; a sixth pipe section connecting the first gas outlet and the compressor, and the seventh pipe section sequentially connecting the compressor and the cooling pipe section until the hydrogen outlet; and the eighth pipe section connecting the second gas outlet and the fourth pipe section.

[0010] Under the structure of the present invention, high-temperature hydrogen flows through the hydrogen inlet-primary heat exchanger-direct cooling gas-liquid separator-compressor-indirect cooling gas-liquid separator in the liquid hydrogen multi-stage pre-cooling system and finally reaches the hydrogen outlet. The heat it carries is gradually absorbed in three sets of cooling devices and finally reduced to the required temperature. The cooling medium used to absorb heat during this period is the liquid hydrogen provided by the liquid hydrogen storage device. During the circulation of liquid hydrogen, it absorbs the heat of high-temperature hydrogen in the primary heat exchanger, direct cooling gas-liquid separator and indirect cooling gas-liquid separator to assist its cooling.

[0011] In the present invention, mainly through the guidance of the fluid by the pipeline, the arrangement order of the primary heat exchanger, the direct cooling gas-liquid separator and the indirect cooling gas-liquid separator, etc., the hydrogen and liquid hydrogen can be evenly and thoroughly exchanged with each other, so that the high-temperature hydrogen can be cooled to the required temperature. In addition, during the cooling period, only the cold released by the vaporization of liquid hydrogen is used and fully utilized, and no other condensing equipment such as the condenser is introduced. At the same time, the hydrogen after the cold is released is fully utilized, and no material waste is caused.

[0012] As a further improvement of the present invention, a first pressure detection device and a first temperature detection device are provided on the first pipe section.

[0013] As a further improvement of the present invention, a transition pipe section is connected between the second pipe section and the third pipe section and the cold side pipeline, and a second temperature detection device, a second pressure detection device, a first valve and a first check valve are provided on the transition pipe section.

[0014] As a further improvement of the present invention, on the fourth pipe segment, a connection point with the eighth pipe segment, a second valve, a second check valve, a third pressure detection device and a third temperature detection device are sequentially arranged along the flow path of the hydrogen.

[0015] As a further improvement of the present invention, a fourth temperature detection device and a fourth pressure detection device are provided on the seventh pipe section between the cooling pipe section and the hydrogen outlet.

[0016] As a further improvement of the present invention, a zigzag hydrogen flow path is formed in the main pipe.

[0017] As a further improvement of the present invention, a bubbling device is connected to the gas inlet, which can disperse the high-temperature hydrogen into fine high-temperature hydrogen bubbles when the high-temperature hydrogen enters the low-temperature liquid hydrogen.

[0018] The amount of high-temperature hydrogen carried in a small single bubble is relatively small, that is, the heat carried in a single bubble is relatively small. Therefore, all the heat of the high-temperature hydrogen in a single bubble can be absorbed by the surrounding low-temperature liquid hydrogen to the greatest extent and as quickly as possible. In this case, it is guaranteed to the greatest extent that all the high-temperature hydrogen introduced can release heat to the low-temperature liquid hydrogen, reducing the possibility that some high-temperature hydrogen will not be cooled due to factors such as the difference in specific heat capacity between the high-temperature hydrogen and the low-temperature liquid hydrogen, that is, reducing the occurrence of uneven heat exchange.

[0019] At the same time, in the direct cooling gas-liquid separator, after the high-temperature hydrogen bubbles leave the low-temperature liquid hydrogen, they will mix with the low-temperature hydrogen produced by the vaporization of liquid hydrogen in the first gas containing area, further reducing the overall temperature of the high-temperature hydrogen and reducing the occurrence of incomplete heat exchange of the high-temperature hydrogen in the direct cooling gas-liquid separator.

[0020] As a further improvement of the present invention, it is characterized in that a ninth pipe segment is connected between the fifth pipe segment and the sixth pipe segment; on the fifth pipe segment, a third valve, a connection point with the ninth pipe segment, a fourth valve and a first gas drive device are sequentially arranged along the flow direction of hydrogen; on the sixth pipe segment, a fifth valve, a connection point with the ninth pipe segment, a fifth temperature detection device, a fifth pressure detection device and a sixth valve are sequentially arranged along the flow direction of hydrogen.

[0021] Under this structure, when the high-temperature hydrogen after the first-stage cooling of the first-stage heat exchanger can meet the temperature requirements before compression, the high-temperature hydrogen can be directly circulated to the compressor by opening the third valve, closing the fourth valve and the first gas drive device, and closing the fifth valve.

[0022] If the high-temperature hydrogen after the first-stage cooling of the first-stage heat exchanger does not meet the temperature requirement before compression, the third valve, the fourth valve and the fifth valve are opened, the sixth valve is closed and the first gas drive device is started, and the high-temperature hydrogen can be driven into the direct-cooling gas-liquid separator for secondary cooling; and if the temperature of the high-temperature hydrogen is still higher than the required temperature after one round of secondary cooling, the third valve can be closed and the operation of introducing the high-temperature hydrogen can be suspended, and the high-temperature hydrogen can be driven by the first gas drive device to cause multiple rounds of cooling in the direct-cooling gas-liquid separator until the temperature requirement before compression is reached.

[0023] The structure expands the range of initial temperatures of high-temperature hydrogen that can be cooled by the liquid hydrogen multi-stage precooling system, and improves the applicability of the liquid hydrogen multi-stage precooling system.

[0024] As a further improvement of the present invention, the direct-cooling gas-liquid separator is connected to a buffer kit, which includes an exhaust pipe, an air storage tank and a reflux pipe; wherein the exhaust pipe is used to connect the gas containing area of ​​the direct-cooling gas-liquid separator and the air storage tank, and an exhaust valve is provided on the exhaust pipe; the reflux pipe is used to connect the first liquid containing area and the air storage tank, and the gas outlet of the reflux pipe is placed in the first liquid containing area, and a second gas drive device and a third check valve are provided on the reflux pipe.

[0025] Since the low-temperature liquid hydrogen in the direct-cooling gas-liquid separator will also vaporize and produce hydrogen after being heated, if multiple rounds of high-temperature hydrogen are circulated and cooled in the direct-cooling gas-liquid separator, it is easy to cause the first gas containing area to be unable to contain and withstand hydrogen. Therefore, under this structure, the buffer kit can temporarily store excess hydrogen, and after the direct-cooling gas-liquid separator discharges the hydrogen inside, the hydrogen stored in the gas storage tank is refluxed to the direct-cooling gas-liquid separator through the reflux pipe for cooling again, and participates in subsequent circulation, ensuring the safe operation of the liquid hydrogen multi-stage precooling system, while not generating hydrogen waste.

[0026] In a second aspect, the present invention provides a hydrogen refueling station, which adopts any one of the above-mentioned liquid hydrogen multi-stage precooling systems to cool the hydrogen.

[0027] The beneficial effects of the present invention include:

[0028] (1) In the liquid hydrogen multi-stage precooling system of the present invention, only liquid hydrogen is used as the cooling medium. The cooling capacity released when the liquid hydrogen is vaporized and converted into hydrogen is used throughout the process to complete the cooling of the high-temperature hydrogen. During the process, no condenser or other equipment is used, so that the overall power consumption of the liquid hydrogen multi-stage precooling system is relatively small, which conforms to the concept of green environmental protection;

[0029] (2) In the liquid hydrogen multi-stage precooling system of the present invention, the hydrogen obtained by the initial conversion after releasing the cold can continue to release cold to further cool the high-temperature hydrogen, and can be used together in the subsequent hydrogenation work, which not only fully utilizes the cold of the hydrogen, but also does not cause waste of the hydrogen itself, thereby reducing the operating cost of the liquid hydrogen multi-stage precooling system;

[0030] (3) After adding the ninth pipeline and other structures, the cooling path of the high-temperature hydrogen can be adjusted according to the detection results of the relevant temperature detection devices installed in the pipe section, further ensuring that all the high-temperature hydrogen introduced during use can be cooled to the required cooling temperature, ensuring the normal implementation of subsequent hydrogenation work. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following drawings are provided for combining with the preferred implementation examples of the present invention to help understand the purpose and advantages of the present invention, wherein:

[0032] Figure 1 This is a schematic diagram of the layout of various devices of the liquid hydrogen multi-stage precooling system in Example 1;

[0033] Figure 2 This is a schematic diagram of the layout of various devices in the liquid hydrogen multi-stage precooling system in Example 2. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below based on the accompanying drawings and implementation examples.

[0035] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] In the embodiments, for ease of understanding, descriptions such as low-temperature liquid hydrogen, high-temperature hydrogen, and low-temperature hydrogen are used, wherein the high and low temperature descriptions of each substance do not limit the specific temperature of the substance. In general, the hydrogen to be cooled has the highest temperature, so it is referred to as high-temperature hydrogen; the hydrogen produced by vaporization of liquid hydrogen after heating has a temperature higher than liquid hydrogen but lower than the hydrogen to be cooled, so it is referred to as low-temperature hydrogen; the temperature of liquid hydrogen is the lowest, so it is referred to as low-temperature liquid hydrogen. The above names do not affect the scope of protection of the present invention.

[0037] Embodiment 1:

[0038] This embodiment provides a liquid hydrogen multi-stage precooling system, which uses the cold released when liquid hydrogen vaporizes to cool the high-temperature hydrogen. The liquid hydrogen multi-stage precooling system mainly includes: a liquid hydrogen storage device 1, a hydrogen inlet 2, a primary heat exchanger 3, a direct cooling gas-liquid separator 4, an indirect cooling gas-liquid separator 5, a compressor 6, a liquid circulation pipeline and a gas circulation pipeline.

[0039] In general, the cold source in the liquid hydrogen multi-stage precooling system, that is, the source of the cooling medium, is the liquid hydrogen storage device 1. The device is used to store liquid hydrogen, but since it is actually difficult to always maintain constant pressure and temperature in the liquid hydrogen storage device 1 during the long-term liquid hydrogen storage time, it will inevitably cause part of the liquid hydrogen to be converted into low-temperature hydrogen in the liquid hydrogen storage device 1. The temperature of such hydrogen is still much lower than the high-temperature hydrogen to be cooled, so in this embodiment, when using liquid hydrogen, the coldness of such low-temperature hydrogen can also be utilized, further enhancing the utilization rate of the hydrogen source.

[0040] The heat source in the liquid hydrogen multi-stage precooling system, that is, the source of the material to be cooled, is the hydrogen inlet 2, which is used to receive high-temperature hydrogen from the outside. In this embodiment, the high-temperature hydrogen is hydrogen at room temperature, that is, hydrogen at about 23°C. When the high-temperature hydrogen enters the liquid hydrogen multi-stage precooling system through the hydrogen inlet 2, it needs to be cooled three times and pressurized by the compressor 6 during this period, and finally forms the required low-temperature high-pressure gas and is transported to the hydrogen outlet for output.

[0041] The three steps of gradual cooling refer to the high-temperature hydrogen gas passing through the primary heat exchanger 3, the direct-cooling gas-liquid separator 4 and the indirect-cooling gas-liquid separator 5 in sequence, and the gas temperature is gradually reduced during this period. The flow path of the high-temperature hydrogen gas and the flow path of the low-temperature hydrogen gas formed after the cold is released are guided by the gas flow pipeline; correspondingly, the flow path of the low-temperature liquid hydrogen or the gas-liquid mixture of liquid hydrogen is mainly guided by the liquid flow pipeline.

[0042] The various devices of the liquid hydrogen multi-stage precooling system are as follows: Figure 1 As shown, the first-stage heat exchanger 3 includes a hot side pipeline 301 and a cold side pipeline 302. The cold side pipeline 302 is connected to the liquid hydrogen storage device 1 through the first pipe section 701 to receive low-temperature liquid hydrogen; and the hot side pipeline 301 is connected to the hydrogen inlet 2 through the fourth pipe section 801 to receive high-temperature hydrogen. In the first-stage heat exchanger 3 of this embodiment, a metal medium is filled between the cold side pipeline 302 and the hot side pipeline 301, so that the low-temperature liquid hydrogen in the cold side pipeline 302 can absorb the heat transferred from the high-temperature hydrogen in the hot side pipeline 301, thereby achieving a first-stage cooling of the high-temperature hydrogen. Alternatively, a plurality of conductive plates can be connected and set between the cold side pipeline 302 and the hot side pipeline 301, and the heat exchange between the cold side pipeline 302 and the hot side pipeline 301 is completed through the conductive plate.

[0043] After passing through the primary heat exchanger 3, the high-temperature hydrogen in the hot side pipeline 301 is cooled in the first stage, and then can enter the direct cooling gas-liquid separator 4 through the fifth pipe section 802 for secondary cooling. The liquid hydrogen in the cold side pipeline 302 is converted into a gas-liquid mixture of liquid hydrogen after being heated. In this gas-liquid mixture, on the one hand, there is still unvaporized low-temperature liquid hydrogen remaining, and on the other hand, the temperature of the generated hydrogen is still much lower than the high-temperature hydrogen introduced from the outside. In general, the cold capacity in the gas-liquid mixture has not been fully utilized, that is, both the residual low-temperature liquid hydrogen and the generated low-temperature hydrogen can continue to participate in the cooling of the high-temperature hydrogen. Therefore, the gas-liquid mixture in the cold side pipeline 302 is diverted and guided to the direct cooling gas-liquid separator 4 and the indirect cooling gas-liquid separator 5 by the second pipe section 702 and the third pipe section 703, respectively, and is still used as a cooling medium for standby.

[0044] like Figure 1 As shown, the direct cooling type gas-liquid separator 4 and the indirect cooling type gas-liquid separator 5 have similarities, both of which are gas-liquid separators, and both of which include a gas containing area placed at the top and a liquid containing area placed at the bottom. Therefore, the first gas outlet 403 and the second gas outlet 503 of the two are both arranged near or at the top, so that the first gas outlet 403 outputs gas through the connected sixth pipe segment 803, and the second gas outlet 503 outputs gas through the connected eighth pipe segment 805; and the first liquid infusion port 401 and the second liquid infusion port 501 of the two are also arranged at the middle position, so as to separate the input gas-liquid mixture into gas and liquid.

[0045] Specifically, when the gas-liquid mixture enters the direct-cooling gas-liquid separator 4 through the second pipe section 702, affected by the density of the gas and liquid, the liquid hydrogen as liquid gradually sinks and accumulates in the first liquid containing area 4-1 of the direct-cooling gas-liquid separator 4, and the low-temperature hydrogen as gas rises to the first gas containing area 4-2 of the direct-cooling gas-liquid separator 4. Similarly, when the gas-liquid mixture enters the indirect-cooling gas-liquid separator 5 through the third pipe section 703, the second liquid containing area 5-1 of the indirect-cooling gas-liquid separator 5 also begins to accumulate and contain low-temperature liquid hydrogen.

[0046] There are also differences between the direct cooling type gas-liquid separator 4 and the indirect cooling type gas-liquid separator 5 .

[0047] like Figure 1 As shown, an air inlet pipe 402 is provided in the direct cooling gas-liquid separator 4, one end of the air inlet pipe 402 is connected to the fifth pipe section 802, and is used to receive the high-temperature hydrogen after the first-level cooling of the first-level heat exchanger 3, and the other end of the air inlet pipe 402 is the air inlet port 402-1, which is arranged in the first liquid containing area 4-1. A check valve can also be added in the air inlet pipe 402 to avoid the backflow of low-temperature liquid hydrogen.

[0048] Under this structure, the direct cooling gas-liquid separator 4 has an operating mode that is different from that of the indirect cooling gas-liquid separator 5. When the high-temperature gas is passed into the direct cooling gas-liquid separator 4, it is first directly passed into the low-temperature liquid hydrogen contained therein. At this time, the high-temperature hydrogen will form bubbles in the low-temperature liquid hydrogen, and then gradually rise. During the rising process, the high-temperature hydrogen will gradually exchange heat with the low-temperature liquid hydrogen to achieve a cooling effect. When the bubbles of high-temperature hydrogen are discharged from the low-temperature liquid hydrogen, they will directly mix with the low-temperature hydrogen in the first gas containing area 4-2. The low-temperature hydrogen contained in the gas containing area is mainly produced by vaporization after the low-temperature liquid hydrogen absorbs heat. The temperature of this type of hydrogen is still lower than that of the high-temperature hydrogen. Therefore, after the two are mixed in the first gas containing area 4-2, the overall temperature of the high-temperature hydrogen is further reduced.

[0049] The above process actually achieves the secondary cooling of the high-temperature hydrogen by the direct-cooling gas-liquid separator 4. After the secondary cooling is completed, the high-temperature hydrogen is transported to the compressor 6 through the first gas outlet 403 and the sixth pipe section 803 connected to the first gas outlet 403, and is pressurized to form the final required high-pressure hydrogen.

[0050] The high-pressure and high-temperature hydrogen gas after being pressurized by the compressor 6 will be passed into the indirect cooling gas-liquid separator 5 through the seventh pipe section 804. Figure 1 As shown, the indirect cooling gas-liquid separator 5 includes a cooling pipe section 502, one end of the cooling pipe section 502 is connected to the compressor 6 through the seventh pipe section 804, and the other end is connected to the hydrogen outlet through the seventh pipe section 804, and the main pipe body 502-1 of the cooling pipe section 502 is placed in the second liquid containing area 5-1.

[0051] Since the high-temperature hydrogen gas to be cooled in the indirect-cooling gas-liquid separator 5 has been pressurized, it is necessary to transport the hydrogen gas through a pipeline in order to keep the hydrogen gas in a high-pressure state. Therefore, during the third-stage cooling process, the main pipe body 502-1 of the cooling pipe section 502 is placed in the low-temperature liquid hydrogen in the second liquid containing area 5-1, and the cooling work is completed by indirect contact between the high-temperature and high-pressure hydrogen gas and the low-temperature liquid hydrogen.

[0052] At the same time, in the indirect cooling gas-liquid separator 5, when the low-temperature liquid hydrogen is heated to produce low-temperature hydrogen, this low-temperature hydrogen can flow back to the fourth pipe section 801 through the eighth pipe section 805, and achieve preliminary mixing with the high-temperature hydrogen in the fourth pipe section 801, so that the remaining cold capacity of the low-temperature hydrogen can be utilized again.

[0053] Therefore, in this embodiment, the operation of the liquid hydrogen multi-stage precooling system is mainly carried out through the following steps:

[0054] First, it is the preliminary operation stage. In this stage, high-temperature hydrogen is introduced slowly and evenly in small quantities, while low-temperature liquid hydrogen is introduced at a constant speed and constant amount. At this time, when passing through the first-stage heat exchanger 3, the cold loss of low-temperature liquid hydrogen is relatively small, so the gas-liquid mixture is still dominated by liquid hydrogen. At this stage, the gas-liquid mixture transmitted from the first-stage heat exchanger 3 can quickly complete the accumulation of low-temperature liquid hydrogen in the direct-cooling gas-liquid separator 4 and the indirect-cooling gas-liquid separator 5. At the same time, since the total amount of high-temperature hydrogen introduced at this time is small and the circulation speed is slow, the high-temperature hydrogen can be fully cooled in the first-stage heat exchanger 3 and the direct-cooling gas-liquid separator 4. Especially when entering the direct-cooling gas-liquid separator 4, the temperature difference between high-temperature hydrogen and low-temperature liquid hydrogen and low-temperature hydrogen is relatively smaller, ensuring that all high-temperature hydrogen can be cooled to the required temperature normally, and there will be no situation such as incomplete heat exchange. After being pressurized by the compressor 6 and cooled by the three-stage cooling of the indirect cooling gas-liquid separator 5, the high-temperature hydrogen is finally cooled to the required hydrogen temperature and pressure requirements.

[0055] Secondly, when the indirect cooling gas-liquid separator 5 can provide a continuous supply of sufficient low-temperature hydrogen through the eighth pipe section 805, it enters the normal operation stage. At this time, the introduction speed of the high-temperature hydrogen is restored to normal speed. In this stage, before the high-temperature hydrogen actually enters the primary heat exchanger 3, the high-temperature hydrogen has been mixed with the low-temperature hydrogen refluxed by the eighth pipe section 805, reaching the first drop in overall temperature. According to the inventor's test, the effect of the overall temperature drop of hydrogen obtained after mixing with low-temperature hydrogen here makes up for the defect of weakened cooling effect caused by the increased circulation speed of high-temperature hydrogen. Especially in the link where high-temperature gas is introduced into the direct cooling gas-liquid separator 4, it is ensured that the high-temperature gas and low-temperature liquid hydrogen and low-temperature hydrogen will not cause incomplete heat exchange due to excessive temperature difference, and the normal and smooth operation of the liquid hydrogen multi-stage precooling system as a whole is ensured.

[0056] Therefore, in this embodiment, the guidance of the fluid by the pipeline, the arrangement order of the direct cooling gas-liquid separator 4 and the indirect cooling gas-liquid separator 5, etc. can be coordinated with each other to ensure that the heat exchange is thorough when the hydrogen and liquid hydrogen are directly mixed, thereby ensuring that the high-temperature hydrogen can be cooled to the required temperature. In addition, during the cooling period, only the cold released by the liquid hydrogen is used, and no equipment such as a condenser is introduced, thereby reducing the corresponding power consumption. At the same time, the hydrogen after the cold is released is fully utilized, without causing waste of materials.

[0057] Preferably, if Figure 1 As shown, a first pressure detection device 701-1 and a first temperature detection device 701-2 are sequentially arranged along the flow path of liquid hydrogen on the first pipe section 701. The corresponding parameters including temperature of low-temperature liquid hydrogen can be monitored, and such parameters can be used as the main basis for estimating and controlling the cooling capacity provided to the liquid hydrogen multi-stage precooling system.

[0058] Preferably, if Figure 1 As shown, the second pipe section 702 and the third pipe section 703 are not directly connected to the cold side pipeline 302, and a transition pipe section 704 is connected between the second pipe section 702, the third pipe section 703 and the cold side pipeline 302. A second temperature detection device 704-1, a second pressure detection device 704-2, a first valve 704-3 and a first check valve 704-4 are sequentially arranged along the flow path of the gas-liquid mixture on the transition pipe section 704. Under this structure, the temperature of the gas-liquid mixture and other conditions can be monitored, and the cooling capacity that can be provided by the direct cooling type gas-liquid separator 4 and the indirect cooling type gas-liquid separator 5 can be estimated and adjusted in real time. At the same time, the first check valve 704-4 and other structures ensure that the gas-liquid mixture will not flow back.

[0059] Preferably, if Figure 1 As shown, on the fourth pipe section 801, the connection point with the eighth pipe section 805, the second valve 801-1, the second check valve 801-2, the third pressure detection device 801-3 and the third temperature detection device 801-4 are sequentially arranged along the flow path of hydrogen. Under this structure, it is guaranteed that the corresponding conditions including the temperature of high-temperature hydrogen can be monitored. Such parameters can be used to estimate the cooling capacity required by the liquid hydrogen multi-stage precooling system, etc., and can be used as one of the basis for adjusting parameters such as the amount of low-temperature liquid hydrogen introduced.

[0060] Preferably, if Figure 1 As shown, a fourth temperature detection device 804-1 and a fourth pressure detection device 804-2 are sequentially arranged on the seventh pipe section 804 between the cooling pipe section 502 and the hydrogen outlet along the hydrogen flow path.

[0061] Preferably, if Figure 1 As shown, a tortuous hydrogen flow path is formed in the main pipe 502-1. Under this structure, the indirect contact area between the high-temperature hydrogen and the low-temperature liquid hydrogen is actually increased, thereby improving the cooling effect of the low-temperature liquid hydrogen on the high-temperature hydrogen flowing in the main pipe 502-1.

[0062] Preferably, a bubbling device is connected to the air inlet 402-1. Under this structure, when high-temperature hydrogen is introduced into the air inlet pipe 402, abundant and tiny high-temperature hydrogen bubbles can be generated in the low-temperature liquid hydrogen, and the amount of high-temperature hydrogen carried in the tiny single bubble is small, that is, the heat carried is small. Therefore, the heat of all the high-temperature hydrogen in a single bubble can be transferred to the surrounding low-temperature liquid hydrogen as quickly and completely as possible. In this case, it is ensured that all the high-temperature hydrogen introduced can transfer heat to the low-temperature hydrogen, reducing the situation where only part of the high-temperature hydrogen is cooled, that is, reducing the occurrence of uneven heat exchange between high-temperature hydrogen and low-temperature liquid hydrogen. At the same time, in combination with the direct cooling gas-liquid separator 4, after the bubbles of high-temperature hydrogen leave the low-temperature liquid hydrogen, the mixing effect of the high-temperature hydrogen and the low-temperature hydrogen further reduces the occurrence of incomplete overall heat exchange of the high-temperature hydrogen.

[0063] Preferably, in this embodiment, the temperature detection devices are all temperature transmitters.

[0064] Embodiment 2:

[0065] The difference between this embodiment and embodiment 1 is that, in this embodiment, Figure 2 As shown, the ninth pipe segment 806 is connected between the fifth pipe segment 802 and the sixth pipe segment 803, so that connection points with the ninth pipe segment 806 are formed on both the fifth pipe segment 802 and the sixth pipe segment 803. Correspondingly, the arrangement order of the remaining devices on the fifth pipe segment 802 and the sixth pipe segment 803 will be related to the above connection points. Specifically, Figure 2 As shown, on the fifth pipe segment 802, a third valve 802-1, a connection point with the ninth pipe segment 806, a fourth valve 802-2 and a first gas drive device 802-3 are sequentially arranged along the flow direction of the high-temperature hydrogen; on the sixth pipe segment 803, a fifth valve 803-1, a connection point with the ninth pipe segment 806, a fifth temperature detection device 803-2, a fifth pressure detection device 803-3 and a sixth valve 803-4 are sequentially arranged along the flow direction of the high-temperature hydrogen.

[0066] Under the structure of this embodiment, the liquid hydrogen multi-stage precooling system can adjust the cooling work steps in real time according to the temperature of the high-temperature hydrogen introduced, the cooling effect of the cooling device such as the first-stage heat exchanger 3, etc.

[0067] Specifically, when the cooling work is carried out, the third valve 802-1 can be opened, the fourth valve 802-2 and the first gas drive device 802-3 can be closed, and the fifth valve 803-1 can be closed. In this state, the high-temperature hydrogen after the first-stage heat exchange can directly pass through the front section of the fifth pipe section 802, the ninth pipe section 806 and the end section of the sixth pipe section 803 in sequence and directly reach the compressor 6. At this time, the fifth temperature detection device 803-2 can detect the corresponding temperature of the high-temperature hydrogen. If it is affected by factors such as the low temperature of the high-temperature hydrogen itself or the slow speed of the high-temperature hydrogen, after cooling through the first-stage heat exchanger 3, the high-temperature hydrogen can reach the required hydrogen temperature before compression, then the high-temperature hydrogen can be directly passed through the sixth valve 803-4 and enter the compressor 6. In the above case, the high-temperature hydrogen in the liquid hydrogen multi-stage precooling system circulates in sequence through the hydrogen inlet 2-the first-stage heat exchanger 3-the compressor 6-the indirect cooling gas-liquid separator 5 and finally reaches the hydrogen outlet.

[0068] When the fifth temperature detection device 803-2 detects that the temperature of the high-temperature hydrogen fails to reach the required temperature, the third valve 802-1, the fourth valve 802-2 and the fifth valve 803-1 are opened, the sixth valve 803-4 is closed and the first gas drive device 802-3 is started. In this state, the high-temperature hydrogen is driven into the direct cooling gas-liquid separator 4 for secondary cooling.

[0069] If the fifth temperature detection device 803-2 detects that the high-temperature hydrogen can reach the temperature required before compression after being cooled by the direct-cooling gas-liquid separator 4, the sixth valve 803-4 is opened. At this time, the high-temperature hydrogen in the liquid hydrogen multi-stage precooling system flows sequentially through the hydrogen inlet 2-primary heat exchanger 3-direct-cooling gas-liquid separator 4-compressor 6-indirect-cooling gas-liquid separator 5 and finally reaches the hydrogen outlet, and it always keeps continuous flow during the process.

[0070] If, due to factors such as the high temperature of the high-temperature hydrogen itself being introduced being too high, after a round of cooling in the direct-cooling gas-liquid separator 4, the fifth temperature detection device 803-2 still detects that the high-temperature hydrogen has failed to reach the temperature required before compression, the sixth valve 803-4 remains closed, and the third valve 802-1 is closed and the introduction of high-temperature hydrogen is suspended. The first gas drive device 802-3 is then used to drive the high-temperature hydrogen to repeatedly enter the first liquid containing area 4-1 of the direct-cooling gas-liquid separator 4 until the high-temperature hydrogen is cooled in the direct-cooling gas-liquid separator 4 and reaches the temperature required before entering compression. The third valve 802-1 and the sixth valve 803-4 are then opened, and the high-temperature hydrogen continues to be introduced to start a new round of cooling work.

[0071] However, when the temperature difference between high-temperature hydrogen and low-temperature liquid hydrogen is too large, directly mixing high-temperature hydrogen and low-temperature liquid hydrogen is likely to cause uneven heat exchange, that is, the temperature of some gases in the cooled high-temperature hydrogen is relatively low while some gases still maintain a relatively high temperature. Therefore, preferably, on the sixth pipe section 803, a sixth temperature detection device 803-5 can be additionally provided between the connection point of the fifth valve 803-1 and the ninth pipe section 806. Under this structure, the detection result of the sixth temperature detection device 803-5 can be compared with the detection result of the fifth temperature detection device 803-2. If the data of the two are quite different, it proves that the overall temperature of the high-temperature hydrogen after the secondary cooling is uneven, so it is necessary to continue to drive the direct cooling gas-liquid separator 4 repeatedly for cooling until the overall temperature of the high-temperature hydrogen reaches the required temperature before compression.

[0072] Furthermore, since the low-temperature liquid hydrogen in the direct-cooling gas-liquid separator 4 will also produce hydrogen after being heated, if the high-temperature hydrogen is circulated and cooled multiple times in the direct-cooling gas-liquid separator 4, it is easy to cause the first gas containing area 4-2 of the direct-cooling gas-liquid separator 4 to be difficult to contain and withstand hydrogen. Therefore, preferably, the direct-cooling gas-liquid separator 4 is connected to a buffer kit 4-3, such as Figure 2 As shown, the buffer kit 4-3 includes an exhaust pipe 4-3-1, an air storage tank 4-3-2 and a return pipe 4-3-3.

[0073] The exhaust pipe 4-3-1 is used to connect the first gas storage area 4-2 and the gas storage tank 4-3-2, and the exhaust pipe 4-3-1 is provided with an exhaust valve 4-3-4. When the pressure in the first gas storage area 4-2 is within the tolerable range, the exhaust valve 4-3-4 is closed, and the buffer kit 4-3 does not need to be activated; when the pressure in the first gas storage area 4-2 is close to the tolerable range and reaches the warning value, the exhaust valve 4-3-4 is opened, and the high-temperature hydrogen enters the gas storage tank 4-3-2 through the exhaust pipe 4-3-1 and is temporarily stored.

[0074] The reflux pipe 4-3-3 is used to connect the first liquid containing area 4-1 and the gas storage tank 4-3-2. The gas outlet of the reflux pipe 4-3-3 is placed in the first liquid containing area 4-1. The reflux pipe 4-3-3 is provided with a second gas drive device 4-3-5 and a third check valve 4-3-6. When the high-temperature hydrogen cooled in the direct cooling gas-liquid separator 4 reaches the temperature requirement and is discharged, the second gas drive device 4-3-5 in the reflux pipe 4-3-3 drives the hydrogen in the gas storage tank 4-3-2 to pass into the first liquid containing area 4-1. After being cooled by the low-temperature liquid hydrogen in the first liquid containing area 4-1, the hydrogen can be discharged out of the direct cooling gas-liquid separator 4, thereby ensuring that the hydrogen will not be wasted.

[0075] Under the structure of this embodiment, the liquid hydrogen multi-stage precooling system is capable of cooling high-temperature hydrogen at a relatively high temperature, thereby improving the applicability of the liquid hydrogen multi-stage precooling system.

[0076] Embodiment 3:

[0077] This embodiment provides a hydrogen refueling station, which uses any one of the liquid hydrogen multi-stage precooling systems in Embodiment 1 or 2 to cool the hydrogen.

[0078] Finally, it should be noted that the above implementation cases are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned implementation cases, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned implementation cases, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the implementation cases of the present invention.

Claims

1. A liquid hydrogen multi-stage precooling system, characterized in that: Contains: A liquid hydrogen storage device (1), used for providing liquid hydrogen; A hydrogen inlet (2) for connecting and introducing hydrogen into the liquid hydrogen multi-stage precooling system; The primary heat exchanger (3) comprises a hot side pipeline (301) and a cold side pipeline (302), wherein the hot side pipeline (301) is used to introduce the hydrogen, and the cold side pipeline (302) is used to introduce the liquid hydrogen, and a heat exchange medium is provided between the hot side pipeline (301) and the cold side pipeline (302) for heat exchange between the liquid hydrogen and the hydrogen; A direct cooling type gas-liquid separator (4), comprising a first liquid inlet (401), an air inlet pipe (402), a first air outlet (403), and a first liquid containing area (4-1) arranged at the bottom of the direct cooling type gas-liquid separator (4), wherein the air inlet (402-1) of the air inlet pipe (402) is placed in the first liquid containing area (4-1); An indirect cooling type gas-liquid separator (5), comprising a second liquid infusion port (501), a cooling pipe section (502), a second gas outlet (503), and a second liquid containing area (5-1) arranged at the bottom of the indirect cooling type gas-liquid separator (5), wherein the main pipe body (502-1) of the cooling pipe section (502) is placed in the second liquid containing area (5-1); A compressor (6) for compressing the hydrogen to form a high-pressure gas; a liquid circulation pipeline for guiding the circulation of the liquid hydrogen or the gas-liquid mixture, comprising a first pipe section (701) connecting the liquid hydrogen storage device (1) and the cold side pipeline (302); a second pipe section (702) and a third pipe section (703) for splitting the gas-liquid mixture flowing out of the cold side pipeline (302) and connecting them to the first liquid infusion port (401) and the second liquid infusion port (501), respectively, so as to guide the liquid hydrogen in the gas-liquid mixture to flow into the first liquid containing area (4-1) and the second liquid containing area (5-1), respectively; A gas circulation pipeline for guiding the circulation of the hydrogen, comprising a fourth pipe section (801) connecting the hydrogen inlet (2) and the hot side pipeline (301); a fifth pipe section (802) connecting the hot side pipeline (301) and the gas inlet pipe (402); a sixth pipe section (803) connecting the first gas outlet (403) and the compressor (6); a seventh pipe section (804) sequentially connecting the compressor (6) and the cooling pipe section (502) until the hydrogen outlet; and an eighth pipe section (805) connecting the second gas outlet (503) and the fourth pipe section (801).

2. A liquid hydrogen multi-stage precooling system according to claim 1, characterized in that: The first pipe section (701) is provided with a first pressure detection device (701-1) and a first temperature detection device (701-2).

3. A liquid hydrogen multi-stage precooling system according to claim 1, characterized in that: A transition pipe section (704) is connected between the second pipe section (702) and the third pipe section (703) and the cold side pipeline (302), and a second temperature detection device (704-1), a second pressure detection device (704-2), a first valve (704-3) and a first check valve (704-4) are provided on the transition pipe section (704).

4. A liquid hydrogen multi-stage precooling system according to claim 1, characterized in that: On the fourth pipe section (801), a connection point with the eighth pipe section (805), a second valve (801-1), a second check valve (801-2), a third pressure detection device (801-3) and a third temperature detection device (801-4) are sequentially arranged along the flow path of the hydrogen.

5. A liquid hydrogen multi-stage precooling system according to claim 1, characterized in that: A fourth temperature detection device (804-1) and a fourth pressure detection device (804-2) are provided on the seventh pipe section (804) between the cooling pipe section (502) and the hydrogen outlet.

6. A liquid hydrogen multi-stage precooling system according to claim 1, characterized in that: A tortuous hydrogen flow path is formed in the main pipe (502-1).

7. A liquid hydrogen multi-stage precooling system according to claim 1, characterized in that: The air inlet (402-1) is connected to a bubbling device.

8. A liquid hydrogen multi-stage precooling system according to any one of claims 1 to 7, characterized in that: A ninth pipe segment (806) is connected between the fifth pipe segment (802) and the sixth pipe segment (803); On the fifth pipe section (802), a third valve (802-1), a connection point with the ninth pipe section (806), a fourth valve (802-2) and a first gas drive device (802-3) are sequentially arranged along the flow direction of the hydrogen; On the sixth pipe section (803), a fifth valve (803-1), a connection point with the ninth pipe section (806), a fifth temperature detection device (803-2), a fifth pressure detection device (803-3) and a sixth valve (803-4) are sequentially arranged along the flow direction of the hydrogen.

9. A liquid hydrogen multi-stage precooling system according to claim 7, characterized in that: The direct cooling gas-liquid separator (4) is connected to a buffer kit (4-3), and the buffer kit (4-3) comprises an exhaust pipe (4-3-1), a gas storage tank (4-3-2), and a return pipe (4-3-3); The exhaust pipe (4-3-1) is used to connect the first gas containing area (4-2) of the direct cooling gas-liquid separator (4) and the gas storage tank (4-3-2), and an exhaust valve (4-3-4) is provided on the exhaust pipe (4-3-1); The reflux pipe (4-3-3) is used to connect the first liquid containing area (4-1) and the gas storage tank (4-3-2); the gas outlet of the reflux pipe (4-3-3) is disposed in the first liquid containing area (4-1); and the reflux pipe (4-3-3) is provided with a second gas drive device (4-3-5) and a third check valve (4-3-6).

10. A hydrogen refueling station, characterized in that: A liquid hydrogen multi-stage precooling system as described in any one of claims 1 to 9 is used to cool the hydrogen.

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