High-efficiency recycling device for pre-cooled mixed gas of low-temperature storage tank

Abstract

The utility model relates to an efficient recycling device for precooling mixed gas of a low-temperature storage tank. The efficient recycling device comprises a liquid inlet pipeline, a liquid hydrogen storage tank, a precooling spray head, a precooling mixed gas storage tank, a low-temperature hydrogen storage tank, a low-temperature nitrogen storage tank and a high-speed cyclone separator which are connected with one another. According to the utility model, the pre-cooled mixed gas is subjected to primary separation by innovatively utilizing standing separation, so that the separation efficiency of the mixed gas is improved, and the purposes of saving the equipment cost, reducing the energy consumption and simplifying the operation are achieved; according to the invention, the high-speed cyclone separator is adopted to carry out secondary separation on the pre-cooled mixed gas, and nitrogen and hydrogen in the mixed gas are efficiently separated by utilizing the advantages of good separation effect, convenience in installation, small size, low energy consumption, good separation effect and the like of the high-speed cyclone separator; the device does not need to add chemical agents such as adsorbents for separation and recovery, and is simple, low in operation difficulty and low in investment and operation cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of separation and recovery of mixed gases generated in the precooling process of liquid hydrogen storage tanks, and particularly relates to a high-efficiency recovery device for precooling mixed gases in low-temperature storage tanks. Background Art

[0002] Hydrogen energy has the characteristics of being clean and carbon-free, green and efficient, renewable, and having rich application scenarios. Therefore, vigorously developing hydrogen energy storage and transportation technology is of great significance.

[0003] When using cryogenic tanks to store liquid hydrogen, the high energy consumption of hydrogen liquefaction necessitates minimizing losses during storage. Therefore, before liquid hydrogen is introduced, the tank is often pre-cooled with liquid nitrogen. Once the tank temperature has dropped, liquid hydrogen is added. After a portion of the liquid hydrogen has been injected, the tank temperature reaches the liquid hydrogen storage temperature. However, during this pre-cooling process, the liquid nitrogen and some of the liquid hydrogen evaporate, producing a low-temperature nitrogen-hydrogen mixture. If this energy is not recovered, the cold energy and materials involved are wasted. Conventional treatment methods include: 1. Directly igniting the mixture at the end of the discharge pipe; this method significantly wastes the cold energy and hydrogen energy of the mixture. 2. Directly recovering the low-temperature gas; recovering the mixture without separation results in poor economic efficiency and poses safety risks. 3. Using adsorbents for adsorption recovery; this requires large amounts of reagents and is costly. None of these treatment methods fully utilize the cold energy and energy contained in the pre-cooled mixture, and their economic benefits are limited.

[0004] If the physical properties of the density difference between hydrogen and nitrogen are reasonably utilized for primary and secondary separation, and cold energy and hydrogen are recovered, it will be safe and environmentally friendly, have high recovery efficiency and good economic benefits. Utility Model Content

[0005] The purpose of the utility model is to address the waste of mixed gas generated by the existing pre-cooling of liquid hydrogen storage tanks and to propose a new, energy-saving, simple structure, good separation effect and high-efficiency recovery device and recovery method for pre-cooling mixed gas in low-temperature storage tanks, which can recycle the cold energy of the mixed gas.

[0006] The utility model is achieved through the following technical solutions:

[0007] The utility model provides a high-efficiency recovery device for pre-cooling mixed gas in a low-temperature storage tank, comprising a liquid inlet pipeline, a liquid hydrogen storage tank, a pre-cooling nozzle, a pre-cooling mixed gas storage tank, a low-temperature hydrogen storage tank, a low-temperature nitrogen storage tank and a high-speed cyclone separator;

[0008] The liquid hydrogen storage tank is connected to the liquid inlet pipeline and is used to receive the liquid sent out by the liquid inlet pipeline;

[0009] The pre-cooling nozzle is arranged in the liquid hydrogen storage tank and connected to the liquid inlet pipeline, and is used to inject liquid nitrogen into the liquid hydrogen storage tank for pre-cooling;

[0010] The pre-cooled mixed gas storage tank is connected to the liquid hydrogen storage tank and is used to receive the mixed gas generated in the liquid hydrogen storage tank and allow it to stand to allow nitrogen and hydrogen to separate into layers;

[0011] The low-temperature hydrogen storage tank is connected to the top of the pre-cooled mixed gas storage tank and the liquid hydrogen storage tank respectively, and is used to receive the hydrogen from the top of the pre-cooled mixed gas storage tank and to deliver the hydrogen into the liquid hydrogen storage tank;

[0012] The low-temperature nitrogen storage tank is connected to the bottom of the pre-cooled mixed gas storage tank and the liquid hydrogen storage tank respectively, and is used to receive the nitrogen at the bottom of the pre-cooled mixed gas storage tank and to deliver the nitrogen into the liquid hydrogen storage tank;

[0013] The high-speed cyclone separator is respectively connected to the middle part of the pre-cooled mixed gas storage tank, the low-temperature hydrogen storage tank, and the low-temperature nitrogen storage tank, and is used to receive the mixed gas in the middle part of the pre-cooled mixed gas storage tank and centrifuge the mixed gas at high speed. The separated hydrogen is sent to the low-temperature hydrogen storage tank, and the separated nitrogen is sent to the low-temperature nitrogen storage tank.

[0014] In order to facilitate the control of liquid inlet of different components, the liquid inlet pipeline includes a first liquid inlet pipeline, a second liquid inlet pipeline, and a third liquid inlet pipeline. A pre-cooling liquid valve is provided on the first liquid inlet pipeline, and the first liquid inlet pipeline is connected to the pre-cooling nozzle. An upper liquid inlet valve is provided on the second liquid inlet pipeline, and the second liquid inlet pipeline extends to the top end of the liquid hydrogen storage tank. A lower liquid inlet valve is provided on the third liquid inlet pipeline, and the third liquid inlet pipeline extends to the bottom end of the liquid hydrogen storage tank.

[0015] In order to facilitate the separation of hydrogen and nitrogen, in a preferred embodiment of the present invention, the high-speed cyclone separator includes a cylinder, an overflow port arranged at the top of the cylinder, an underflow port arranged at the bottom of the cylinder, and a feed port arranged on the side of the cylinder. The cylinder is conical, and its diameter gradually decreases from top to bottom. The inclination angle range of the conical cylinder is 72-86°.

[0016] Furthermore, a Laval nozzle is installed in the feed port, and the Laval nozzle includes an inlet section, a tapering section, and a gradually expanding section that are integrally formed and connected in sequence. The diameter of the inlet section is larger than the diameter of the tapering section, and the diameter of the tapering section gradually decreases from one end close to the inlet section to the other end away from the inlet section, and the diameter of the gradually expanding section gradually increases from one end close to the tapering section to the other end away from the tapering section.

[0017] Among them, the diameter of the entrance section is 100-146mm, the length of the entrance section is 75-93mm, the length of the tapering section is 210-258mm, the length of the gradually expanding section is 210-268mm, the diameter of one end of the gradually expanding section close to the tapering section is 15-23mm, and the diameter of the other end of the gradually expanding section away from the tapering section is 19-32mm.

[0018] The utility model mainly adopts the combination of static stratification and high-speed cyclone separation to perform graded separation and recovery. The mixed gas is first allowed to stand in a low-temperature storage tank. After the hydrogen and nitrogen are gradually stratified, a compressor is used to extract the hydrogen and nitrogen from the top and bottom of the tank respectively, and inject them into their respective storage tanks for standby. Subsequently, the residual mixed gas in the tank is subjected to secondary separation by a high-speed cyclone separator. After centrifugal separation, hydrogen is discharged from the upper outlet of the separator, and nitrogen is discharged from the lower outlet of the separator, and finally recovered low-temperature nitrogen and low-temperature hydrogen are obtained. A Laval nozzle is provided at the feed port of the separator to further cool and accelerate the mixed gas, thereby improving the separation efficiency. The recovered low-temperature gas is also further recycled and utilized for cold energy, that is, the recovered gas is utilized in the subsequent pre-cooling link of the storage tank, which efficiently utilizes the energy wasted in the traditional solution.

[0019] In summary, the beneficial effects of the present invention are:

[0020] (1) The utility model innovatively uses static separation to perform initial separation on the pre-cooled mixed gas, thereby improving the separation efficiency of the mixed gas, thereby achieving the purpose of saving equipment costs, reducing energy consumption, and simplifying operations;

[0021] (2) The invention adopts a high-speed cyclone separator to perform secondary separation on the pre-cooled mixed gas, and utilizes its advantages of good separation effect, convenient installation, compact size, low energy consumption, and separation effect to efficiently separate the nitrogen and hydrogen in the mixed gas;

[0022] (3) The utility model does not require the addition of chemical agents such as adsorbents for separation and recovery, and the device is simple, easy to operate, and has low investment and operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of the utility model's low-temperature storage tank pre-cooling mixed gas efficient recovery device;

[0024] Figure 2 This is a schematic structural diagram of a high-speed cyclone separator of the present utility model;

[0025] Figure 3 This is a schematic structural diagram of the Laval nozzle of the present invention. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0027] like Figure 1 The device shown is a high-efficiency recovery device for pre-cooling mixed gas in a cryogenic storage tank, comprising a liquid inlet pipeline 1, a liquid hydrogen storage tank 5, a pre-cooling nozzle 6, a pre-cooling mixed gas storage tank 8, a cryogenic hydrogen storage tank 10, a cryogenic nitrogen storage tank 12 and a high-speed cyclone separator 14.

[0028] Specifically, the liquid hydrogen storage tank 5 is connected to the liquid inlet pipeline 1, and the liquid inlet pipeline includes a first liquid inlet pipeline, a second liquid inlet pipeline, and a third liquid inlet pipeline. The first liquid inlet pipeline is provided with a precooling liquid valve 2, and the first liquid inlet pipeline is connected to the precooling nozzle 6, and the precooling nozzle 6 is provided at the top of the liquid hydrogen storage tank 5. The second liquid inlet pipeline is provided with an upper liquid inlet valve 3, and the second liquid inlet pipeline extends to the top of the liquid hydrogen storage tank 5. The third liquid inlet pipeline is provided with a lower liquid inlet valve 4, and the third liquid inlet pipeline extends to the bottom of the liquid hydrogen storage tank 5. The precooled mixed gas storage tank 8 is connected to the liquid hydrogen storage tank 6 through a compressor 7, and the low-temperature hydrogen storage tank 10 is connected to the precooled mixed gas storage tank 8 through a compressor 9. The top of the mixed gas storage tank 8 is connected, the low-temperature hydrogen storage tank 10 is connected to the liquid hydrogen storage tank 5 through a compressor 17, the low-temperature nitrogen storage tank 12 is connected to the bottom of the pre-cooled mixed gas storage tank 8 through a compressor 11, and the low-temperature nitrogen storage tank 12 is connected to the liquid hydrogen storage tank 5 through a compressor 18. A recovery gas pre-cooling valve 19 is provided on the connecting pipeline of the low-temperature hydrogen storage tank 10, the low-temperature nitrogen storage tank 12 and the liquid hydrogen storage tank 5. The high-speed cyclone separator 14 is connected to the middle part of the pre-cooled mixed gas storage tank 8 through a compressor 13, the top of the high-speed cyclone separator 14 is connected to the low-temperature hydrogen storage tank 10 through a compressor 15, and the bottom of the high-speed cyclone separator 14 is connected to the low-temperature nitrogen storage tank 12 through a compressor 16.

[0029] Specifically, combined Figure 2 As shown, the high-speed cyclone separator includes a cylinder 20, an overflow port 21 provided at the top of the cylinder 20, an underflow port 22 provided at the bottom of the cylinder 20, and a feed port 23 provided on the side of the cylinder 20. The cylinder 20 is conical, and its diameter gradually decreases from top to bottom. The inclination angle of the conical cylinder 20 ranges from 72 to 86 degrees. The overflow port 21 is connected to the low-temperature hydrogen storage tank 10, the underflow port 22 is connected to the low-temperature nitrogen storage tank 12, and the feed port 23 is connected to the middle of the pre-cooling mixed gas storage tank 8;

[0030] The feed port 23 is provided with a Laval nozzle. Figure 3As shown, the Laval nozzle includes an inlet section 2301, a tapered section 2302, and a diverging section 2303 that are integrally formed and sequentially connected. To ensure the stability of the airflow, the Witosinski curve is used to form the structure of the Laval nozzle tapered section, and the curve satisfies the following formula:

[0031]

[0032] Where: R is the cross-sectional radius at any axial distance x of the tapered section, mm; x is the axial distance, mm; r cr ——throat radius, mm; r1——diameter of the tapered section, mm; L——length of the tapered section, mm;

[0033] Therefore, in the present invention, the diameter of the inlet section 2301 is larger than the diameter of the tapered section 2302. The diameter of the inlet section 2301 is 100-146 mm, and the length of the inlet section is 75-93 mm. The diameter of the tapered section 2302 gradually decreases from one end close to the inlet section 2301 (the left end of the tapered section 2302) to the other end away from the inlet section 2301 (the right end of the tapered section 2302). The length of the tapered section 2302 is 210-25 mm. 8mm, the diameter of the gradually expanding section 2303 gradually increases from one end close to the gradually contracting section 2302 (the left end of the gradually expanding section 2303) to the other end away from the gradually contracting section 2302 (the right end of the gradually expanding section 2303), the gradually expanding section 2303 is 210-268mm long, the diameter of one end of the gradually expanding section 2303 close to the gradually contracting section 2302 is 15-23mm, and the diameter of the other end of the gradually expanding section 2303 away from the gradually contracting section 2302 is 19-32mm.

[0034] During use, first open the pre-cooling liquid valve 2 and pass liquid nitrogen into the pre-cooling nozzle 6 to pre-cool the liquid hydrogen storage tank 5. This process produces a large amount of low-temperature nitrogen. After the temperature in the tank drops to a suitable temperature, open the upper liquid inlet valve 3 to inject liquid hydrogen into the liquid hydrogen storage tank 5. Since the temperature of liquid nitrogen is higher than the storage temperature of liquid hydrogen, part of the liquid hydrogen injected into the tank will also evaporate and produce a large amount of low-temperature hydrogen. This part of the pre-cooled mixed gas is pumped into the pre-cooled mixed gas storage tank 8 through the compressor 7 and allowed to stand for 1 to 2 days. Due to the density difference between hydrogen and nitrogen, part of the hydrogen will accumulate above the pre-cooled mixed gas storage tank 8 and be pumped into the low-temperature hydrogen storage tank 10 by the compressor 9; at the same time, part of the nitrogen will accumulate at the bottom of the pre-cooled mixed gas storage tank 8 and be pumped into the low-temperature nitrogen storage tank by the compressor 11. 12; and there is still some mixed gas in the middle area of ​​the pre-cooling mixed gas storage tank 8 that has not been completely separated, and it needs to be extracted to the high-speed cyclone separator 14 through the compressor 13. Due to the density difference and high-speed centrifugal effect, the hydrogen with lower density will escape from the upper port of the high-speed cyclone separator 14 and be extracted into the low-temperature hydrogen storage tank 10 through the compressor 15, and the nitrogen with higher density will escape from the lower port of the high-speed cyclone separator 14 and be extracted into the low-temperature nitrogen storage tank 12 through the compressor 16; Regarding the utilization of cold energy of recycled gas: during the next pre-cooling, the stored recycled gas can be extracted through compressors 17 and 18 and the recycled gas pre-cooling valve 19 can be opened for pre-cooling. If the temperature of the stored gas after recovery is not enough for pre-cooling, it can be directly recycled as energy.

[0035] In order to ensure that the centrifugal effect of the high-speed cyclone separator 14 meets the requirements, the pipeline between the compressor 13 and the high-speed cyclone separator 14 should not be too long; all equipment must use insulation materials to avoid waste of cooling energy.

[0036] Finally, it should be noted that the above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A high-efficiency recovery device for pre-cooling mixed gas in a cryogenic storage tank, characterized by: Including liquid inlet pipeline, liquid hydrogen storage tank, pre-cooling nozzle, pre-cooling mixed gas storage tank, cryogenic hydrogen storage tank, cryogenic nitrogen storage tank and high-speed cyclone separator; The liquid hydrogen storage tank is connected to the liquid inlet pipeline and is used to receive the liquid sent out by the liquid inlet pipeline; The pre-cooling nozzle is arranged in the liquid hydrogen storage tank and connected to the liquid inlet pipeline, and is used to inject liquid nitrogen into the liquid hydrogen storage tank for pre-cooling; The pre-cooled mixed gas storage tank is connected to the liquid hydrogen storage tank and is used to receive the mixed gas generated in the liquid hydrogen storage tank and allow it to stand to allow nitrogen and hydrogen to separate into layers; The low-temperature hydrogen storage tank is connected to the top of the pre-cooled mixed gas storage tank and the liquid hydrogen storage tank respectively, and is used to receive the hydrogen from the top of the pre-cooled mixed gas storage tank and to deliver the hydrogen into the liquid hydrogen storage tank; The low-temperature nitrogen storage tank is connected to the bottom of the pre-cooled mixed gas storage tank and the liquid hydrogen storage tank respectively, and is used to receive the nitrogen at the bottom of the pre-cooled mixed gas storage tank and to deliver the nitrogen into the liquid hydrogen storage tank; The high-speed cyclone separator is respectively connected to the middle part of the pre-cooled mixed gas storage tank, the low-temperature hydrogen storage tank, and the low-temperature nitrogen storage tank, and is used to receive the mixed gas in the middle part of the pre-cooled mixed gas storage tank and centrifuge the mixed gas at high speed. The separated hydrogen is sent to the low-temperature hydrogen storage tank, and the separated nitrogen is sent to the low-temperature nitrogen storage tank.

2. The high-efficiency recovery device for pre-cooled mixed gas in a cryogenic storage tank according to claim 1 is characterized in that: The liquid inlet pipeline includes a first liquid inlet pipeline, a second liquid inlet pipeline, and a third liquid inlet pipeline. The first liquid inlet pipeline is provided with a pre-cooling liquid valve, and the first liquid inlet pipeline is connected to the pre-cooling nozzle. The second liquid inlet pipeline is provided with an upper liquid inlet valve, and the second liquid inlet pipeline extends to the top end of the liquid hydrogen storage tank. The third liquid inlet pipeline is provided with a lower liquid inlet valve, and the third liquid inlet pipeline extends to the bottom end of the liquid hydrogen storage tank.

3. The high-efficiency recovery device for pre-cooling mixed gas in a cryogenic storage tank according to claim 1 is characterized in that: The high-speed cyclone separator includes a cylinder, an overflow port arranged at the top of the cylinder, an underflow port arranged at the bottom of the cylinder, and a feed port arranged on the side of the cylinder. The cylinder is conical, and its diameter gradually decreases from top to bottom. The inclination angle range of the conical cylinder is 72-86°.

4. The high-efficiency recovery device for pre-cooling mixed gas in a cryogenic storage tank according to claim 3 is characterized in that: A Laval nozzle is installed in the feed port, and the Laval nozzle includes an inlet section, a tapered section, and a gradually expanding section that are integrally formed and connected in sequence. The diameter of the inlet section is larger than the diameter of the tapered section. The diameter of the tapered section gradually decreases from one end close to the inlet section to the other end away from the inlet section, and the diameter of the gradually expanding section gradually increases from one end close to the tapered section to the other end away from the tapered section.

5. The high-efficiency recovery device for pre-cooling mixed gas in a cryogenic storage tank according to claim 4 is characterized in that: The diameter of the entrance section is 100-146 mm, the length of the entrance section is 75-93 mm, the length of the tapering section is 210-258 mm, the length of the gradually expanding section is 210-268 mm, the diameter of one end of the gradually expanding section close to the tapering section is 15-23 mm, and the diameter of the other end of the gradually expanding section away from the tapering section is 19-32 mm.

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