Test system for subcritical low-temperature ejector of hydrogen liquefaction equipment

Abstract

The invention provides a test system for a subcritical low-temperature ejector of hydrogen liquefaction equipment, which comprises the subcritical low-temperature ejector, a high-pressure hydrogen supply device, a liquid hydrogen storage tank and first heat exchange equipment, and is characterized in that the subcritical low-temperature ejector is provided with a high-pressure inlet connecting pipe, a low-pressure inlet connecting pipe and a medium-pressure outlet connecting pipe; the high-pressure hydrogen supply device is used for providing a high-pressure stream required by testing and is connected with the high-pressure inlet connecting pipe; the liquid hydrogen storage tank is used for storing liquid hydrogen and providing a low-pressure stream required by testing, and is connected with the low-pressure inlet connecting pipe; the first heat exchange equipment is provided with a first heat exchange flow channel and a second heat exchange flow channel for heat exchange, the two ends of the first heat exchange flow channel are connected with the medium-pressure outlet connecting pipe and the liquid hydrogen storage tank correspondingly, and a first refrigerating medium flows through the second heat exchange flow channel. And the mixed gas passing through the first heat exchange runner is cooled to a first preset temperature by the first refrigerating medium and returns to the liquid hydrogen storage tank. According to the invention, the performance of the subcritical low-temperature ejector can be tested safely, accurately and truly.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen energy utilization equipment, and in particular relates to a testing system for a subcritical low-temperature ejector of hydrogen liquefaction equipment. Background Art

[0002] As a "zero-carbon" clean energy source, hydrogen energy is abundant, renewable, clean, and efficient. It only releases water during use, and does not emit other harmful gases or solid particles. Its development and utilization is an inevitable trend in future energy development. Liquid hydrogen has become a form of hydrogen energy product that countries are vying to develop due to its high hydrogen density, low storage and transportation pressure, high gasification purity, and high cost advantages. The explosive growth of terminal applications in the civilian hydrogen energy industry has in turn driven the demand for large-scale, low-energy consumption liquid hydrogen technology. For large-scale liquid hydrogen plants, even a small efficiency improvement can have a significant impact on the economic viability of the entire system.

[0003] In the production process of large-scale hydrogen liquefaction equipment, a hydrogen turbine expansion refrigeration cycle process is generally used, and the final stage cooling process to the liquid hydrogen temperature zone relies on throttling of the low-temperature hydrogen throttle valve. In the liquid hydrogen production process, after the final stage hydrogen throttling, the low-temperature hydrogen cannot be completely liquefied, and a large amount of gaseous hydrogen will be produced. This part of hydrogen flows into the liquid hydrogen storage tank together with the liquid hydrogen. On the one hand, it will reduce the liquefaction rate of hydrogen in the hydrogen liquefaction equipment, and on the other hand, it will cause the pressure in the liquid hydrogen storage tank to continue to rise. In the actual production of hydrogen liquefaction, in order to ensure the safety of the storage tank, when the pressure reaches the set upper limit, the low-temperature hydrogen in the tank needs to be vented, which will greatly lose liquid hydrogen production and reduce the utilization rate of liquid hydrogen.

[0004] In some hydrogen liquefaction equipment, a hydrogen ejector is installed to cool and liquefy the liquid hydrogen again after evaporation inside the storage tank. Specifically, a high-pressure working fluid flows into the hydrogen ejector, expands and reduces the pressure, and becomes a high-speed, low-pressure fluid. The hydrogen vapor at the ejection end is then introduced into the ejector's suction chamber. This portion of hydrogen vapor represents the evaporation caused by the conversion of normal and para-hydrogen in the liquid hydrogen storage tank. The hydrogen vapor at the ejected end leaves the hydrogen ejector after passing through the mixing chamber and diffusion chamber, and flows into the heat exchanger for heat exchange and cooling, achieving re-liquefaction. This process can effectively utilize cold energy and prevent the evaporated hydrogen from flowing back to the compressor, resulting in cold energy loss during the process.

[0005] However, when the high-pressure working fluid is in a subcritical state, conventional hydrogen ejectors will become clogged, affecting the normal operation of the hydrogen liquefaction equipment. Therefore, it is necessary to introduce subcritical cryogenic ejectors into the hydrogen liquefaction equipment to improve system efficiency. However, there are currently few studies on the performance testing of subcritical cryogenic ejectors used in hydrogen liquefaction equipment, and there is no suitable method to calibrate their performance. On the one hand, if the subcritical cryogenic ejector is directly added to the hydrogen liquefaction equipment, the testing cost is too high, and if the subcritical cryogenic ejector fails to achieve the actual working effect, it may cause damage to other components in the hydrogen liquefaction equipment. On the other hand, without relying on hydrogen liquefaction equipment, it is difficult to obtain a two-phase mixture of liquid hydrogen and hydrogen and high-pressure and low-temperature hydrogen below -240°C, which makes it difficult to build a test platform.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome at least some of the shortcomings of the existing technology and provide a testing system for subcritical cryogenic ejectors used in hydrogen liquefaction equipment, aiming to safely, accurately and truly realize the performance test of subcritical cryogenic ejectors used in hydrogen liquefaction equipment, and evaluate their performance under actual working conditions, and provide guidance for the subsequent design of larger flow and higher efficiency ejectors.

[0008] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0009] A test system for a subcritical cryogenic ejector of a hydrogen liquefaction device, comprising:

[0010] A subcritical low-temperature ejector is provided with a high-pressure inlet pipe, a low-pressure inlet pipe and a medium-pressure outlet pipe;

[0011] A high-pressure hydrogen supply device, used to provide the high-pressure flow required for the test, connected to the high-pressure inlet pipe;

[0012] A liquid hydrogen storage tank is used to store liquid hydrogen and provide the low-pressure flow required for testing, and is connected to the low-pressure inlet pipe;

[0013] The first heat exchange device has a first heat exchange channel and a second heat exchange channel for heat exchange, wherein the two ends of the first heat exchange channel are respectively connected to the medium-pressure outlet pipe and the liquid hydrogen storage tank, and the second heat exchange channel is used to flow through the first refrigerant medium, and the mixed gas passing through the first heat exchange channel is cooled by the first refrigerant medium to a first preset temperature and returns to the liquid hydrogen storage tank.

[0014] In some embodiments, the first refrigerant is liquid helium, which is used to cool the mixed gas passing through the first heat exchange channel to a liquid hydrogen temperature range.

[0015] In some embodiments, the high-pressure hydrogen providing device comprises:

[0016] The second heat exchange device has a third heat exchange channel and a fourth heat exchange channel for heat exchange, wherein both ends of the third heat exchange channel are respectively connected to the hydrogen source and the high-pressure inlet pipe, and the fourth heat exchange channel is used to flow through the second refrigerant medium. The hydrogen passing through the third heat exchange channel is cooled to a second preset temperature by the second refrigerant medium and then enters the high-pressure inlet pipe.

[0017] In some embodiments, the second refrigerant is liquid nitrogen, which is used to cool the hydrogen passing through the third heat exchange channel to a liquid nitrogen temperature range.

[0018] In some embodiments, a testing system for a subcritical cryogenic ejector of a hydrogen liquefaction device further includes a first mass flow meter and a second mass flow meter;

[0019] Wherein, the first mass flow meter is provided on the connecting pipeline between the liquid hydrogen storage tank and the low-pressure inlet pipe, or the first mass flow meter is provided on the connecting pipeline between the high-pressure hydrogen supply device and the high-pressure inlet pipe, for obtaining a first mass flow rate;

[0020] The second mass flow meter is provided on the connecting pipeline between the first heat exchange channel and the liquid hydrogen storage tank, and is used to obtain a second mass flow rate;

[0021] The performance of the subcritical cryogenic ejector is evaluated using the first mass flow rate and the second mass flow rate.

[0022] In some embodiments, a testing system for a subcritical cryogenic ejector of a hydrogen liquefaction plant includes a vacuum housing;

[0023] The subcritical low-temperature ejector, the high-pressure hydrogen supply device, the first heat exchange device, the first mass flow meter and the second mass flow meter are all arranged in the vacuum housing.

[0024] In some embodiments, the subcritical low-temperature ejector has an ejection flow channel therein, and the ejection flow channel includes a high-pressure inlet section, a high-pressure nozzle section, a low-pressure ejection section, a mixing section, and a diffusion section;

[0025] The inlet of the high-pressure inlet section has a first cross-sectional area, the outlet of the high-pressure nozzle section has a second cross-sectional area, and the outlet of the diffuser section has a third cross-sectional area;

[0026] The ratio S1 between the first cross-sectional area and the second cross-sectional area satisfies the following formula:

[0027] 7.5<S1<15;

[0028] The ratio S2 between the first cross-sectional area and the third cross-sectional area satisfies the following formula:

[0029] 0.5<S2<0.8.

[0030] In some embodiments, the subcritical cryoejector comprises:

[0031] An outer shell, wherein a side wall of the outer shell is provided with an induced gas inlet;

[0032] a high-pressure inner shell, wherein the high-pressure inlet section and the high-pressure nozzle section are sequentially formed in the high-pressure inner shell, the high-pressure inner shell is disposed within the outer shell, and the first end of the high-pressure inner shell is configured as a conical structure, and the first end of the high-pressure inner shell is located downstream of the ejector gas inlet;

[0033] The intermediate-pressure inner shell, the mixing section and the diffusion section are sequentially formed in the intermediate-pressure inner shell, the intermediate-pressure inner shell is arranged in the outer shell and the first end of the intermediate-pressure inner shell is arranged as a conical cylindrical structure, the first end of the intermediate-pressure inner shell is located downstream of the first end of the high-pressure inner shell, and the low-pressure ejection section connected to the ejection gas inlet is formed between the first end of the intermediate-pressure inner shell and the high-pressure inner shell.

[0034] In some embodiments, the inner diameter of the outer shell corresponding to the high-pressure inner shell is smaller than the inner diameter of the outer shell corresponding to the medium-pressure inner shell.

[0035] In some embodiments, the high-pressure inner shell, the intermediate-pressure inner shell, and the outer shell are interference fit.

[0036] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0037] 1. The test system for subcritical cryogenic ejectors used in hydrogen liquefaction equipment provided by the present invention is designed to safely, accurately, and realistically implement performance testing of subcritical cryogenic ejectors used in hydrogen liquefaction equipment, evaluate their performance under actual working conditions, and provide guidance for the subsequent design of ejectors with larger flow rates and higher efficiency.

[0038] 2. The test system for the subcritical cryogenic ejector of hydrogen liquefaction equipment provided by the present invention utilizes the subcritical cryogenic ejector to extract the flash steam in the liquid hydrogen storage tank and re-liquefy it, and utilizes the first heat exchange device to reduce its temperature to the liquid hydrogen temperature zone before returning it to the liquid hydrogen storage tank. This not only improves the liquefaction rate of the entire system and achieves the purpose of energy saving and cost saving, but also because the liquid hydrogen storage tank is designed to have a low pressure resistance, the internal flash steam will increase the internal pressure of the storage tank, which is not conducive to liquid hydrogen storage. This can be beneficial to the safety of the liquid hydrogen storage tank and liquid hydrogen storage.

[0039] 3. The test system for the subcritical cryogenic ejector of hydrogen liquefaction equipment provided by the present invention uses liquid helium to reduce the temperature of the mixed gas to the liquid hydrogen temperature range, which can more accurately reproduce the actual working conditions of the subcritical cryogenic ejector when it is actually used in the hydrogen liquefaction equipment, and can more efficiently and accurately evaluate the performance of the subcritical cryogenic ejector under actual working conditions.

[0040] 4. The test system for the subcritical cryogenic ejector of hydrogen liquefaction equipment provided by the present invention reasonably optimizes the ejection flow path of the subcritical cryogenic ejector, controls the ratio between the first cross-sectional area of ​​the high-pressure inlet section and the second cross-sectional area of ​​the high-pressure nozzle section, and the ratio between the first cross-sectional area of ​​the high-pressure inlet section and the third cross-sectional area of ​​the diffusion section within a reasonable range, thereby avoiding blockage of the subcritical cryogenic ejector.

[0041] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0043] Figure 1 2 is a schematic structural diagram of a test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to an exemplary embodiment of the present invention;

[0044] Figure 2 2 is a schematic structural diagram of a subcritical cryogenic ejector for a hydrogen liquefaction device according to an exemplary embodiment of the present invention;

[0045] Figure 3 is a schematic structural diagram of an outer shell provided according to an exemplary embodiment of the present invention;

[0046] Figure 4 is a schematic structural diagram of a high-pressure inner shell provided according to an exemplary embodiment of the present invention;

[0047] Figure 5 2 is a schematic structural diagram of a medium-pressure inner shell according to an exemplary embodiment of the present invention.

[0048] In the figure: 100, subcritical cryogenic ejector; 10, outer shell; 11, ejector gas inlet; 12, low-pressure inlet pipe; 13, measuring interface; 14, measuring pipe; 15, low-pressure ejector section; 20, high-pressure inner shell; 21, high-pressure inlet section; 22, high-pressure nozzle section; 23, conical structure; 24, high-pressure inlet pipe; 25, first high-pressure inner half shell; 26, second high-pressure inner half shell; 30, intermediate-pressure inner shell; 31, mixing section; 32, diffusion section; 33, discharge section; 34, conical structure; 35, intermediate-pressure outlet pipe; 36, measuring guide pipe flow channel; 37, first intermediate-pressure inner half shell; 38, second intermediate-pressure inner half shell;

[0049] 200, second heat exchange equipment; 201, liquid nitrogen inlet pipe; 202, nitrogen outlet pipe; 203, second pressure transmitter; 204, second temperature transmitter; 205, hydrogen source;

[0050] 300, liquid hydrogen storage tank; 301, venting pipeline; 302, third pressure transmitter; 303, third temperature transmitter; 304, second pneumatic regulating valve; 305, first mass flow meter;

[0051] 400, first heat exchange device; 401, low-temperature helium inlet pipe; 402, helium outlet pipe; 403, first pressure transmitter; 404, first temperature transmitter; 405, first pneumatic control valve; 406, second mass flow meter;

[0052] 500. Vacuum shell.

[0053] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0055] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0056] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0057] As mentioned above, there are few studies on the performance testing of subcritical cryogenic ejectors used in hydrogen liquefaction equipment, and there is no suitable method to calibrate their performance. Based on this, the present invention provides a test system for subcritical cryogenic ejectors used in hydrogen liquefaction equipment, including a subcritical cryogenic ejector, a high-pressure hydrogen supply device, a liquid hydrogen storage tank and a first heat exchange device, wherein the subcritical cryogenic ejector is provided with a high-pressure inlet pipe, a low-pressure inlet pipe and a medium-pressure outlet pipe; the high-pressure hydrogen supply device is used to provide the high-pressure flow required for the test, which is connected to the high-pressure inlet pipe; the liquid hydrogen storage tank is used to store liquid hydrogen and provide the low-pressure flow required for the test, which is connected to the low-pressure inlet pipe; the first heat exchange device has a first heat exchange channel and a second heat exchange channel for heat exchange, wherein the two ends of the first heat exchange channel are respectively connected to the medium-pressure outlet pipe and the liquid hydrogen storage tank, and the second heat exchange channel is used to flow through a first refrigerant, and the mixed gas passing through the first heat exchange channel is cooled to a first preset temperature by the first refrigerant and returned to the liquid hydrogen storage tank. The above scheme can safely, accurately and realistically implement the performance test of subcritical cryogenic ejectors used in hydrogen liquefaction equipment, evaluate their performance under actual working conditions, and provide guidance for the subsequent design of larger flow and higher efficiency ejectors.

[0058] The preferred technical solutions of the hydrogen liquefaction equipment, the subcritical cryogenic ejector 100 used therefor, and the testing system for testing the subcritical cryogenic ejector 100 provided by the present invention are described below with reference to the accompanying drawings.

[0059] Figure 1 2 is a schematic structural diagram of a test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to an exemplary embodiment of the present invention; Figure 2 2 is a schematic structural diagram of a subcritical cryogenic ejector 100 for a hydrogen liquefaction device according to an exemplary embodiment of the present invention; Figure 3 is a schematic structural diagram of an outer shell 10 provided according to an exemplary embodiment of the present invention; Figure 4 is a structural schematic diagram of a high-pressure inner shell 20 provided according to an exemplary embodiment of the present invention; Figure 5 3 is a schematic structural diagram of a medium-pressure inner shell 30 provided according to an exemplary embodiment of the present invention.

[0060] like Figures 1 to 5 As shown, the test system for the subcritical cryogenic ejector of the hydrogen liquefaction equipment includes a subcritical cryogenic ejector 100, a high-pressure hydrogen supply device, a liquid hydrogen storage tank 300 and a first heat exchange device 400, wherein the subcritical cryogenic ejector 100 is provided with a high-pressure inlet pipe 24, a low-pressure inlet pipe 12 and a medium-pressure outlet pipe 35; the high-pressure hydrogen supply device is used to provide the high-pressure flow required for the test, and is connected to the high-pressure inlet pipe 24; the liquid hydrogen storage tank 300 is used to store liquid hydrogen and provide the low-pressure flow required for the test, and is connected to the low-pressure inlet pipe 12; the first heat exchange device 400 has a first heat exchange flow channel and a second heat exchange flow channel for heat exchange, wherein the two ends of the first heat exchange flow channel are respectively connected to the medium-pressure outlet pipe 35 and the liquid hydrogen storage tank 300, and the second heat exchange flow channel is used to flow through a first refrigerant, and the mixed gas passing through the first heat exchange flow channel is cooled to a first preset temperature by the first refrigerant and returns to the liquid hydrogen storage tank 300.

[0061] Furthermore, the high-pressure hydrogen providing device includes a second heat exchange device 200, and the second heat exchange device 200 has a third heat exchange channel and a fourth heat exchange channel for heat exchange, wherein the two ends of the third heat exchange channel are respectively connected to the hydrogen source 205 and the high-pressure inlet pipe 24, and the fourth heat exchange channel is used to flow through the second refrigerant medium. The hydrogen passing through the third heat exchange channel is cooled to a second preset temperature by the second refrigerant medium and then enters the high-pressure inlet pipe 24.

[0062] Specifically, the second heat exchange channel of the first heat exchange device 400 is connected at both ends to a low-temperature helium inlet pipe 401 and a helium outlet pipe 402, respectively, for supplying the first refrigerant, liquid helium, to the second heat exchange channel. The fourth heat exchange channel of the second heat exchange device 200 is connected at both ends to a liquid nitrogen inlet pipe 201 and a nitrogen outlet pipe 202, respectively, for supplying the second refrigerant, liquid nitrogen, to the fourth heat exchange channel.

[0063] Furthermore, a first pressure transmitter 403 and a first temperature transmitter 404 are provided on the connecting pipeline between the first heat exchange channel of the first heat exchange device 400 and the liquid hydrogen storage tank 300 to record pressure and temperature changes in the medium-pressure exhaust path of the subcritical cryogenic ejector 100. A second pressure transmitter 203 and a second temperature transmitter 204 are provided on the connecting pipeline between the third heat exchange channel of the second heat exchange device 200 and the high-pressure inlet pipe 24 of the subcritical cryogenic ejector 100 to record pressure and temperature changes in the high-pressure inlet path of the subcritical cryogenic ejector 100. A third pressure transmitter 302 and a third temperature transmitter 304 are provided on the connecting pipeline between the liquid hydrogen storage tank 300 and the low-pressure inlet pipe 24 of the subcritical cryogenic ejector 100 to record pressure and temperature changes in the low-pressure inlet path of the subcritical cryogenic ejector 100.

[0064] Furthermore, a first pneumatic control valve 405 is installed on the connecting pipeline between the first heat exchange channel of the first heat exchange device 400 and the liquid hydrogen storage tank 300 to enable remote control of the test system and control of the medium-pressure exhaust flow rate. A second pneumatic control valve 304 is also installed on the connecting pipeline between the liquid hydrogen storage tank 300 and the low-pressure inlet pipe of the subcritical cryogenic ejector 100 to enable remote control of the test system and control of the low-pressure return air flow rate.

[0065] Furthermore, the test system for the subcritical cryogenic ejector 100 of the hydrogen liquefaction equipment also includes a first mass flowmeter 305 and a second mass flowmeter 406; wherein, the first mass flowmeter 305 is arranged on the connecting pipeline between the liquid hydrogen storage tank 300 and the low-pressure inlet pipe, or the first mass flowmeter 305 is arranged on the connecting pipeline between the high-pressure hydrogen supply device and the high-pressure inlet pipe, for obtaining a first mass flow F1.

[0066] The second mass flow meter 406 is provided on the connecting pipeline between the first heat exchange channel and the liquid hydrogen storage tank 300 , and is used to obtain a second mass flow F2 .

[0067] The performance of the subcritical cryogenic ejector 100 is evaluated using the first mass flow rate and the second mass flow rate.

[0068] Specifically, the performance of the subcritical cryogenic ejector 100 is evaluated using the ejection ratio ε=F1 / (F2-F1).

[0069] Furthermore, the liquid hydrogen storage tank 300 is also connected to a venting pipeline 301 , on which a flame arrester is installed for venting hydrogen at a high point and preventing the flame generated by the possible combustion of hydrogen from entering the hydrogen pipeline in reverse and causing an explosion.

[0070] Furthermore, a liquid hydrogen pump and a vaporizer are provided on the connecting pipeline between the third heat exchange flow channel of the second heat exchange device 200 and the high-pressure inlet pipe of the subcritical low-temperature ejector 100 .

[0071] In some embodiments, the test system for the subcritical low-temperature ejector 100 of the hydrogen liquefaction equipment further includes a vacuum housing 500, the interior of the vacuum housing 500 is evacuated to maintain an internal low-temperature environment and reduce heat loss. It is understandable that the vacuum housing 500 is connected to a vacuum pump for evacuating the interior of the vacuum housing 500. Insulation cotton is provided on the outer wall of the vacuum housing 500 for keeping cold. In other words, the vacuum housing 500 is equivalent to a cold box in an actual hydrogen liquefaction equipment. Among them, the subcritical low-temperature ejector 100, the high-pressure hydrogen providing device, the first heat exchange device 400, the first mass flowmeter 305 and the second mass flowmeter 406 are all arranged in the vacuum housing 500.

[0072] In the above scheme, the entire system provides a gas-liquid two-phase mixed working condition through the self-pressurization function of the liquid hydrogen storage tank 300. The liquid hydrogen pump pressurizes and vaporizes the liquid hydrogen in the vaporizer to provide high-pressure, low-temperature liquid hydrogen working conditions, thereby achieving the high and low pressure input conditions required by the subcritical cryogenic ejector 100. Furthermore, the use of pneumatic control valves, pressure transmitters, and temperature transmitters enables remote control and remote data recording of the entire system, allowing for more efficient and accurate assessment of the equipment's performance under actual operating conditions.

[0073] Moreover, the above scheme can more accurately reproduce the actual working conditions of the subcritical low-temperature ejector 100 when it is actually used in hydrogen liquefaction equipment, and can repeatedly test the performance of the equipment, and can realize remote override and remote data reading, with high safety, and can be used repeatedly in actual tests.

[0074] It should be pointed out that the above-mentioned components can adopt structures commonly used in the art that can realize the functions of the present invention, and the present invention does not impose any restrictions here.

[0075] like Figures 2 to 5As shown, the subcritical cryogenic ejector 100 includes an outer shell 10 , a high-pressure inner shell 20 and an intermediate-pressure inner shell 30 . In which, an induced gas inlet 11 is opened on the side wall of the outer shell 10, and the induced gas inlet 11 can also be welded with a low-pressure inlet pipe 12; the high-pressure inlet section 21 and the high-pressure nozzle section 22 are sequentially formed in the high-pressure inner shell 20, the high-pressure inner shell 20 is arranged in the outer shell 10 and the first end of the high-pressure inner shell 20 is set as a conical structure 23, and the first end of the high-pressure inner shell 20 (the outlet of the high-pressure nozzle section 22) is located downstream of the induced gas inlet 11; the mixing section 31 and the diffuser section 32 are sequentially formed in the medium-pressure inner shell 30, the medium-pressure inner shell 30 is arranged in the outer shell 10 and the first end of the medium-pressure inner shell 30 (the inlet of the mixing section 31) is set as a conical structure 34, the first end of the medium-pressure inner shell 30 is located downstream of the first end of the high-pressure inner shell 20, and the low-pressure induced gas inlet 11 is connected to the first end of the high-pressure inner shell 20. The low-pressure induced gas inlet 15 is formed between the medium-pressure inner shell 30 and the first end. In other words, the low-pressure ejection section 15 is a conical annular gap with a certain thickness formed between the first end of the high-pressure inner shell 20 and the first end of the medium-pressure inner shell 30 .

[0076] Furthermore, a high-pressure inlet pipe 24 is welded to the high-pressure inlet section 21 , and a discharge section 33 is provided downstream of the diffuser section 32 in the medium-pressure inner shell 30 , and a medium-pressure outlet pipe 35 is welded to the discharge section 33 .

[0077] In actual operation, low-temperature hydrogen in the hydrogen liquefaction equipment, which has not yet dropped to the liquid hydrogen temperature zone, is used as a high-pressure gas source. It enters the high-pressure inlet section 21 of the subcritical low-temperature ejector 100 from the high-pressure inlet pipe 24, and then undergoes adiabatic expansion through the high-pressure nozzle section 22 to convert pressure into kinetic energy. The flow rate increases but the pressure drops, forming a low-pressure area in the mixing section 31 of the medium-pressure inner shell 30, thereby sucking the incompletely liquefied low-temperature hydrogen into the mixing section 31 through the low-pressure inlet pipe 12 and the low-pressure ejector section 15. After the two are mixed in the mixing section 31, they enter the diffusion section 32 of the medium-pressure inner shell 30. After the kinetic energy of the mixed gas in the diffusion section 32 is converted back into pressure energy, it is discharged through the discharge section 33 and the medium-pressure outlet pipe 35, and returns to the hydrogen liquefaction equipment for circulation and heat exchange, and is re-liquefied into liquid hydrogen.

[0078] It should be pointed out that the temperature of the low-temperature hydrogen in the hydrogen liquefaction equipment that has not yet dropped to the liquid hydrogen temperature zone is approximately 25K, which is lower than the critical point of hydrogen, and the pressure is approximately 2MPa, which is higher than the critical point of hydrogen. Therefore, at this time, the low-temperature hydrogen serving as a high-pressure gas source is in a subcritical state, and the hydrogen density in the subcritical state is much greater than the gaseous hydrogen density.

[0079] It needs to be explained here that, when the low-temperature hydrogen serving as the high-pressure gas source enters the subcritical low-temperature ejector 100 from the high-pressure inlet section 21, due to the high pressure, the phase state at this time is liquid, the medium density is relatively large, and it is accelerated in the high-pressure nozzle section 22. The pressure energy is converted into kinetic energy, the pressure gradually decreases, the medium is converted from liquid hydrogen to hydrogen, the density is greatly reduced by dozens of times, and the volume expands rapidly. At this time, if the throat size of the high-pressure nozzle section 22 is set unreasonably, for example, it is set to a size suitable for liquid media, the throat diameter will be too small, and the medium will not be able to pass smoothly, resulting in a blocking effect. When the throat diameter is too large, the medium will not be able to be fully accelerated in the high-pressure nozzle section 22, and the ejection process will not be completed.

[0080] The present invention limits the ratio of the area of ​​the first cross-section (at section 1-1, similarly below) of the high-pressure inlet section 21 to the area of ​​the second cross-section (at section 2-2) of the high-pressure nozzle section 22 to between 7.5 and 15. This ensures that the ejection process is completed regardless of changes in the inlet flow rate of the high-pressure inlet section 21. Furthermore, the ratio of the area of ​​the first cross-section of the high-pressure inlet section 21 to the area of ​​the third cross-section (at section 3-3) of the diffuser section 32 is limited to between 0.5 and 0.8, fully accounting for the deceleration of the mixed gas and making it suitable for the piping layout requirements within the cold box.

[0081] Optionally, the subcritical cryogenic ejector 100 can be applied to hydrogen liquefaction equipment with a capacity of 0.5 tons / day to 30 tons / day, effectively increasing the hydrogen liquefaction rate and improving the system operation efficiency.

[0082] In some embodiments, as Figure 5 As shown, a measuring lead pipe flow channel 36 is provided on the side wall of the medium-pressure inner shell 30 at a position corresponding to the mixing section 31 and / or the diffuser section 32, for measuring the pressure of the mixing section 31 and / or the diffuser section 32; wherein a measuring interface 13 is provided on the outer shell 10 at a position corresponding to the measuring lead pipe flow channel 36, referring to Figure 3 Furthermore, the measuring interface 13 may be welded with a measuring connecting pipe 14 .

[0083] In the above solution, a measuring pipe flow channel 36 is provided on the side wall of the medium-pressure inner shell 30 at a position corresponding to the mixing section 31 and / or the diffuser section 32 to measure the gas pressure in the mixing section 31 and / or the diffuser section 32. The gas pressure can be used to analyze in real time whether the working status of the subcritical cryogenic ejector 100 is normal, thereby adjusting the process parameters to ensure that the hydrogen can be 100% liquefied.

[0084] In some embodiments, as Figure 3As shown, the inner diameter of the outer shell 10 corresponding to the high-pressure inner shell 20 is smaller than the inner diameter of the outer shell 10 corresponding to the medium-pressure inner shell 30. This makes the flow path of the tapered annular slit-shaped low-pressure ejection section 15 more uniform, ensuring uniform jet velocity distribution, reducing the impact pressure loss when the low-pressure fluid enters, and suppressing the generation of initial vortexes.

[0085] In some embodiments, flanges are provided at the second end of the high-pressure inner shell 20 and the end of the outer shell 10, and the two flanges are welded to achieve a fixed connection between the second end of the high-pressure inner shell 20 and the end of the outer shell 10. Flanges are also provided at the second end of the medium-pressure inner shell 30 and the end of the outer shell 10, and the two flanges are welded to achieve a fixed connection between the second end of the medium-pressure inner shell 30 and the end of the outer shell 10.

[0086] In the above solution, all interfaces of the subcritical cryogenic ejector 100 are directly welded to reduce leakage risk points and ensure equipment safety.

[0087] In some embodiments, the high-pressure inner shell 20 and the medium-pressure inner shell 30 are interference-fitted with the outer shell 10 to prevent the medium from not flowing along the preset flow path and affecting the injection effect.

[0088] In some embodiments, as Figure 4 As shown, the high-pressure inner shell 20 includes a first high-pressure inner half shell 25 and a second high-pressure inner half shell 26, which are axially joined by fastening and welding. The first high-pressure inner half shell 25 and the second high-pressure inner half shell 26 have mirror-image symmetry in appearance. The intermediate-pressure inner shell 30 includes a first intermediate-pressure inner half shell 37 and a second intermediate-pressure inner half shell 38, which are axially joined by fastening and welding. The first intermediate-pressure inner half shell 37 and the second intermediate-pressure inner half shell 38 have mirror-image symmetry in appearance. The measuring lead flow channel 36 is provided on the first intermediate-pressure inner half shell 37 and / or the second intermediate-pressure inner half shell 38.

[0089] As an example, the high-pressure inner shell 20 is a cylindrical blank that is cut along the axis into a first high-pressure inner half shell 25 and a second high-pressure inner half shell 26 and then processed separately to form the high-pressure inlet section 21 and the high-pressure nozzle section 22 inside, and then welded and fixed along the cut seam, and then welded and fixed at the high-pressure inlet section 21 and the high-pressure inlet pipe 24.

[0090] like Figure 5As shown, the intermediate-pressure inner shell 30 is a cylindrical blank that is cut along the axis into a first intermediate-pressure inner half shell 37 and a second intermediate-pressure inner half shell 38. These are then processed separately to form the mixing section 31, the diffuser section 32, and the discharge section 33. These sections are then welded along the cuts and secured to the discharge section 33. Finally, the discharge section 33 is welded to the intermediate-pressure outlet pipe 35. Measuring conduit channels 36 are drilled in the mixing section 31 and the diffuser section 32 to facilitate reading the pressure values ​​at these locations.

[0091] like Figure 3 As shown, the outer shell 10 is processed as a whole, and holes are punched at positions corresponding to the low-pressure injection section 15 and the measuring guide pipe flow channel 36 to form the injection gas inlet 11 and the measuring interface 13, and then the high-pressure inner shell 20 and the medium-pressure inner shell 30 are pressed into the cavity of the outer shell 10 by external force.

[0092] The present invention also provides a hydrogen liquefaction device, comprising a multi-stage heat exchanger and the above-mentioned subcritical low-temperature ejector 100, wherein the subcritical low-temperature ejector 100 is arranged between any two stages of the multi-stage heat exchanger.

[0093] Preferably, the subcritical low-temperature ejector 100 is disposed between the penultimate stage and the penultimate stage heat exchangers.

[0094] As an example, taking the Chinese patent application number CN202011189284.5 as an example, it discloses a hydrogen liquefaction equipment provided with three turbine expander units in series, including a vacuum box, a hydrogen purification device, a precooling device, a first hydrogen compressor unit, a second hydrogen compressor unit, a first turbine expander unit, a second turbine expander unit, a third turbine expander unit, a first low-temperature adsorber, a second low-temperature adsorber, a heat exchanger, a normal-para hydrogen converter, a regulating valve, a throttle valve and a liquid hydrogen storage tank; the precooling device, the first turbine expander unit, the second turbine expander unit, the third turbine expander unit, the first low-temperature adsorber, the second low-temperature adsorber, the heat exchanger, the normal-para hydrogen converter and and the throttle valve are installed in the vacuum box; the regulating valve includes a first regulating valve and a second regulating valve; the throttle valve includes a first throttle valve and a second throttle valve; the heat exchanger includes a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger and a fifth heat exchanger; the first heat exchanger is provided with a first high-pressure hydrogen channel, a first medium-pressure hydrogen channel, a first low-pressure hydrogen channel, a first raw hydrogen channel, a liquid nitrogen channel and a nitrogen channel; the second heat exchanger is provided with a second high-pressure hydrogen channel, a second medium-pressure hydrogen channel, a second low-pressure hydrogen channel and two second raw hydrogen channels; the third heat exchanger is provided with a third high-pressure hydrogen channel, a third medium-pressure hydrogen channel, a third low-pressure hydrogen channel and two third raw hydrogen channels ; A fourth high-pressure hydrogen channel, a fourth medium-pressure hydrogen channel, a fourth low-pressure hydrogen channel and two fourth raw hydrogen channels are provided in the fourth heat exchanger; a fifth low-pressure hydrogen channel and a fifth raw hydrogen channel are provided in the fifth heat exchanger; the pre-cooling device includes a liquid nitrogen tank, the liquid nitrogen tank is provided with a liquid nitrogen supply pipeline for supplying liquid nitrogen, a liquid nitrogen siphon pipeline connecting the liquid phase space at the bottom of the liquid nitrogen tank and the gas phase space at the top, and a nitrogen discharge pipeline for discharging nitrogen in the liquid nitrogen tank; the liquid nitrogen siphon pipeline is connected to the liquid nitrogen channel in the first heat exchanger for cooling the first heat exchanger by absorbing heat through liquid nitrogen vaporization; the nitrogen discharge pipeline is connected to the nitrogen channel in the first heat exchanger; the normal-parahydrogen converter includes a first normal-para hydrogen converter, a second normal-para hydrogen converter, a third normal-para hydrogen converter, a fourth normal-para hydrogen converter, a fifth normal-para hydrogen converter, and a sixth normal-para hydrogen converter; the sixth normal-para hydrogen converter is installed in the fifth heat exchanger; the hydrogen purification device is used to purify the raw hydrogen, the outlet of the hydrogen purification device is connected to the inlet of the first low-temperature adsorber through the first raw hydrogen channel, and the outlet of the first low-temperature adsorber is connected to the first normal-para hydrogen converter and the second normal-para hydrogen converter in sequence; the inlet of a second raw hydrogen channel is connected to the outlet of the second normal-para hydrogen converter, and the outlet is connected to the inlet of a third raw hydrogen channel in sequence through the third normal-para hydrogen converter and another second raw hydrogen channel;The two third raw hydrogen channels are connected through the fourth normal-para hydrogen converter, and the outlet of the other third raw hydrogen channel is connected to the inlet of a fourth raw hydrogen channel; the two fourth raw hydrogen channels are connected through the fifth normal-para hydrogen converter, and the outlet of the other fourth raw hydrogen channel is connected to the inlet of the fifth raw hydrogen channel; the sixth normal-para hydrogen converter is provided in the fifth raw hydrogen channel, and the outlet of the fifth raw hydrogen channel is connected to the inlet of the liquid hydrogen storage tank through the first throttle valve; the inlet of the first hydrogen compressor unit is connected to the outlet of the first low-pressure hydrogen channel, and the outlet is connected to the The inlet of the second hydrogen compressor unit is connected to the outlet of the first medium-pressure hydrogen channel; the outlet of the second hydrogen compressor unit is connected to the inlet of the first high-pressure hydrogen channel; the first regulating valve is connected between the inlet and outlet of the first hydrogen compressor unit; the second regulating valve is connected between the inlet and outlet of the second hydrogen compressor unit; the second low-temperature adsorber is connected between the outlet of the first high-pressure hydrogen channel and the inlet of the second high-pressure hydrogen channel; one outlet of the second high-pressure hydrogen channel is connected via the first turbine expander unit, the second turbine expander unit and the third turbine expander unit connected in series. The unit is connected to the inlet of the fourth medium-pressure hydrogen channel, and the other outlet is connected to the third high-pressure hydrogen channel, the fourth high-pressure hydrogen channel and the second throttle valve connected in sequence, and the outlet of the second throttle valve is connected to the inlet of the fifth low-pressure hydrogen channel; the fourth medium-pressure hydrogen channel, the third medium-pressure hydrogen channel, the second medium-pressure hydrogen channel and the first medium-pressure hydrogen channel are connected in sequence; the fifth low-pressure hydrogen channel, the fourth low-pressure hydrogen channel, the third low-pressure hydrogen channel, the second low-pressure hydrogen channel and the first low-pressure hydrogen channel are connected in series in sequence; the hydrogen purification device, the first low-pressure hydrogen channel and the third low-pressure hydrogen channel are connected in series. The warm adsorber, the normal-para hydrogen converter, the first throttle valve, and the liquid hydrogen storage tank form a hydrogen cooling and liquefaction system; the first hydrogen compressor unit, the second hydrogen compressor unit, the first turbine expander unit, the second turbine expander unit, the third turbine expander unit, the second low-temperature adsorber, the regulating valve, and the second throttle valve form a hydrogen refrigeration cycle system, which uses hydrogen as the refrigerant; the second normal-para hydrogen converter is installed in the liquid nitrogen tank and immersed in liquid nitrogen; two first low-temperature adsorbers are provided, and the two first low-temperature adsorbers are connected in parallel.

[0095] When the subcritical low-temperature ejector 100 of the present invention is applied to the above-mentioned hydrogen liquefaction equipment, the subcritical low-temperature ejector 100 can be placed near the sixth positive para-hydrogen converter, the high-pressure inlet pipe 24 is connected to the fifth positive para-hydrogen converter, that is, the high-pressure inlet stream comes from the hydrogen stream of the fifth positive para-hydrogen converter, the low-pressure inlet pipe 12 is connected to the liquid hydrogen storage tank, that is, the low-pressure inlet stream comes from the liquid hydrogen storage tank, and the medium-pressure outlet pipe 35 is connected to the sixth positive para-hydrogen converter, that is, after the high-pressure inlet stream and the low-pressure inlet stream pass through the subcritical low-temperature ejector 100, the two are mixed into a medium-pressure stream, and then pass through the fifth raw hydrogen channel again for final heat exchange and throttling and pressure reduction by the first throttle valve, and are re-liquefied into liquid hydrogen, thereby improving the liquefaction rate of the equipment.

[0096] In other words, after the hydrogen liquefaction equipment provided by the Chinese patent with application number CN202011189284.5 is improved, the hydrogen flow stream flowing out of the fifth normal para-hydrogen converter no longer directly enters the sixth normal para-hydrogen converter, but enters the high-pressure inlet section 21 of the subcritical low-temperature ejector 100. In addition, a flow path is drawn out from the liquid hydrogen storage tank and connected to the low-pressure inlet pipe 12 of the subcritical low-temperature ejector 100, and the medium-pressure flow stream flowing out of the medium-pressure outlet pipe 35 of the subcritical low-temperature ejector 100 enters the sixth normal para-hydrogen converter.

[0097] In the above scheme, since the temperature difference between the high-pressure stream and the low-pressure stream between the penultimate and penultimate heat exchangers is small, they are easier to mix, and the energy and temperature loss after mixing are low. Therefore, the subcritical low-temperature ejector 100 is set here, and after throttling and reducing the pressure through the first throttle valve behind it, the hydrogen can be 100% re-liquefied into liquid hydrogen, which can more effectively improve the liquefaction rate of the equipment.

[0098] It's important to note that the subcritical cryogenic ejector 100 is housed inside a high-vacuum cold box, which maintains a stable internal temperature. Therefore, in actual use, the subcritical cryogenic ejector 100 needs to be wrapped with insulation material to better maintain the temperature of the liquid hydrogen within the device and minimize the impact of ambient temperature on device performance.

[0099] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present invention can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A test system for a subcritical cryogenic ejector of a hydrogen liquefaction device, characterized in that: include: A subcritical low-temperature ejector is provided with a high-pressure inlet pipe, a low-pressure inlet pipe and a medium-pressure outlet pipe; A high-pressure hydrogen supply device, used to provide the high-pressure flow required for the test, connected to the high-pressure inlet pipe; A liquid hydrogen storage tank is used to store liquid hydrogen and provide the low-pressure flow required for testing, and is connected to the low-pressure inlet pipe; The first heat exchange device has a first heat exchange channel and a second heat exchange channel for heat exchange, wherein the two ends of the first heat exchange channel are respectively connected to the medium-pressure outlet pipe and the liquid hydrogen storage tank, and the second heat exchange channel is used to flow through the first refrigerant medium, and the mixed gas passing through the first heat exchange channel is cooled by the first refrigerant medium to a first preset temperature and returns to the liquid hydrogen storage tank.

2. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 1, characterized in that: The first refrigerant is liquid helium, which is used to cool the mixed gas passing through the first heat exchange channel to a liquid hydrogen temperature range.

3. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 1, characterized in that: The high-pressure hydrogen providing device comprises: The second heat exchange device has a third heat exchange channel and a fourth heat exchange channel for heat exchange, wherein both ends of the third heat exchange channel are respectively connected to the hydrogen source and the high-pressure inlet pipe, and the fourth heat exchange channel is used to flow through the second refrigerant medium. The hydrogen passing through the third heat exchange channel is cooled to a second preset temperature by the second refrigerant medium and then enters the high-pressure inlet pipe.

4. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 3, characterized in that: The second refrigerant is liquid nitrogen, which is used to cool the hydrogen passing through the third heat exchange channel to a liquid nitrogen temperature range.

5. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to any one of claims 1 to 4, characterized in that: Also included are a first mass flow meter and a second mass flow meter; Wherein, the first mass flow meter is provided on the connecting pipeline between the liquid hydrogen storage tank and the low-pressure inlet pipe, or the first mass flow meter is provided on the connecting pipeline between the high-pressure hydrogen supply device and the high-pressure inlet pipe, for obtaining a first mass flow rate; The second mass flow meter is provided on the connecting pipeline between the first heat exchange channel and the liquid hydrogen storage tank, and is used to obtain a second mass flow rate; The performance of the subcritical cryogenic ejector is evaluated using the first mass flow rate and the second mass flow rate.

6. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 5, characterized in that: Also included is a vacuum housing; The subcritical low-temperature ejector, the high-pressure hydrogen supply device, the first heat exchange device, the first mass flow meter and the second mass flow meter are all arranged in the vacuum housing.

7. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to any one of claims 1 to 4, characterized in that: The subcritical low-temperature ejector has an ejection flow channel inside, and the ejection flow channel includes a high-pressure inlet section, a high-pressure nozzle section, a low-pressure ejection section, a mixing section and a diffusion section; The inlet of the high-pressure inlet section has a first cross-sectional area, the outlet of the high-pressure nozzle section has a second cross-sectional area, and the outlet of the diffuser section has a third cross-sectional area; The ratio S1 between the first cross-sectional area and the second cross-sectional area satisfies the following formula: 7.5＜S1＜15； The ratio S2 between the first cross-sectional area and the third cross-sectional area satisfies the following formula: 0.5＜S2＜0.8。 8. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 7, characterized in that: The subcritical cryogenic ejector comprises: An outer shell, wherein a side wall of the outer shell is provided with an induced gas inlet; a high-pressure inner shell, wherein the high-pressure inlet section and the high-pressure nozzle section are sequentially formed in the high-pressure inner shell, the high-pressure inner shell is disposed within the outer shell, and the first end of the high-pressure inner shell is configured as a conical structure, and the first end of the high-pressure inner shell is located downstream of the ejector gas inlet; The intermediate-pressure inner shell, the mixing section and the diffusion section are sequentially formed in the intermediate-pressure inner shell, the intermediate-pressure inner shell is arranged in the outer shell and the first end of the intermediate-pressure inner shell is arranged as a conical cylindrical structure, the first end of the intermediate-pressure inner shell is located downstream of the first end of the high-pressure inner shell, and the low-pressure ejection section connected to the ejection gas inlet is formed between the first end of the intermediate-pressure inner shell and the high-pressure inner shell.

9. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 8, characterized in that: The inner diameter of the outer shell corresponding to the high-pressure inner shell is smaller than the inner diameter of the outer shell corresponding to the medium-pressure inner shell.

10. The test system for a subcritical cryogenic ejector of a hydrogen liquefaction device according to claim 8, characterized in that: The high-pressure inner shell, the medium-pressure inner shell and the outer shell are interference fit.

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