Low-turbulence liquid hydrogen storage tank capable of eliminating thermal stratification

Abstract

A liquid hydrogen storage tank capable of eliminating thermal stratification with low turbulence relates to the field of liquid hydrogen storage and comprises a tank body and a spray rod mechanism arranged in the tank body, the spray rod mechanism is communicated with a liquid hydrogen circulation pipeline, and liquid hydrogen in the tank body is extracted by the liquid hydrogen circulation pipeline and sprayed to a heat leakage point through the spray rod mechanism. The spray rod mechanism comprises a main guide pipe and a plurality of branch guide pipes, the tail ends of the branch guide pipes are provided with distribution assemblies attached to the heat leakage points, and the distribution assemblies are of structures defined by elastic metal wire meshes and filled with porous media, so that liquid hydrogen is dispersed and sprayed to the heat leakage points through the porous media, and turbulence of the liquid hydrogen is reduced. The spray rod mechanism is arranged in the storage tank, and the liquid hydrogen is directly sprayed to the heat leakage point by utilizing the guide pipe and the distribution component of the spray rod mechanism, so that turbulence of the liquid hydrogen in the tank is reduced, and evaporation of the liquid hydrogen caused by heat leakage is slowed down.

Description

Technical Field

[0001] The invention relates to the field of liquid hydrogen storage, in particular to a liquid hydrogen storage tank with low turbulence and heat stratification elimination. Background Art

[0002] Traditional fossil energy sources such as coal, oil, and natural gas are becoming increasingly depleted, and the greenhouse effect and environmental pollution problems are becoming more and more serious. It has become very urgent to obtain and use new energy sources. The only product of hydrogen combustion is water, and there are no other greenhouse gases and pollutants emitted. It has the characteristics of abundant resources, renewability, and storability, and can meet the requirements of resources, environment, and sustainable development at the same time. Therefore, it is considered to be one of the most promising alternatives to fossil energy and is regarded as the clean energy with the greatest development potential in the 21st century. With the rapid development of the hydrogen industry chain, there are many constraints that restrict the popularization of hydrogen energy, and the storage of liquid hydrogen is one of the bottlenecks.

[0003] During the storage of liquid hydrogen, heat leakage will cause a temperature gradient in the tank, which in turn causes a density gradient, which in turn causes natural convection, and finally natural convection causes thermal stratification. Thermal stratification will intensify local evaporation, leading to an excessively rapid increase in pressure in the tank, shortening the storage period of liquid hydrogen, increasing the number of exhaust times of the liquid hydrogen tank, and causing unnecessary waste of resources. In order to extend the storage period of the liquid hydrogen tank, it is necessary to eliminate the thermal stratification phenomenon in the tank.

[0004] In the prior art, large-scale liquid hydrogen spraying is generally used to eliminate thermal stratification. For example, the invention patent with application number 2018100300470 discloses a cryogenic liquid hydrogen storage tank with exhaust cold energy utilization, which discloses a spray rod, and uses the spray rod to spray the cooled fluid into the tank body. "The spraying of the fluid increases the disturbance between the gas and liquid phases in the tank, improves the heat exchange efficiency, and is conducive to the rapid reduction of the tank pressure." However, it is found in practice that this large-scale spraying only temporarily eliminates the thermal stratification on the surface, and does not eliminate the thermal stratification from the root. Local continuous heat leakage will still cause repeated thermal stratification in the storage tank, and then repeated large-scale spraying is required, which further increases the turbulence inside the storage tank and accelerates the evaporation of liquid hydrogen. Summary of the invention

[0005] In order to solve the problem in the prior art of using a large-scale liquid hydrogen spraying method to eliminate thermal stratification in a storage tank, which leads to increased turbulence in the storage tank, the present invention provides a liquid hydrogen storage tank with low turbulence for eliminating thermal stratification. Liquid hydrogen is sprayed to the leakage hot spots in a dispersed manner through a special structure, thereby fundamentally reducing turbulence during liquid hydrogen spraying.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence includes a tank body and a spray rod mechanism arranged inside the tank body. The spray rod mechanism is communicated with the liquid hydrogen circulation pipeline, so that the liquid hydrogen circulation pipeline extracts the liquid hydrogen in the tank body and sprays it to the heat leakage point through the spray rod mechanism. The spray rod mechanism includes a main guiding pipe and a plurality of branch guiding pipes. The end of the branch guiding pipe is provided with a dispersion assembly that fits the heat leakage point. The dispersion assembly is a structure surrounded by an elastic metal wire mesh, and a porous medium is filled inside it, so that the liquid hydrogen is dispersed and sprayed onto the heat leakage point through the porous medium, reducing the turbulence of the liquid hydrogen.

[0007] As an optimized scheme of the above liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, the heat leakage points are rough areas distributed on the inner wall of the tank body, and the roughness Ra of the rough areas is ≥12.5, and the Ra of the remaining areas of the inner wall is ≤0.8.

[0008] As another optimized scheme of the above liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, the heat leakage points are convex areas distributed on the inner wall of the tank body, and the surface roughness Ra of the convex areas is ≥12.5, and the Ra of the remaining areas of the inner wall is ≤0.8.

[0009] As another optimized scheme of the above liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, the heat leakage points correspond to the connection points of the support of the tank body.

[0010] As another optimized scheme of the above liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, the liquid hydrogen circulation pipeline has a circulation pump, and the circulation pump extracts the liquid hydrogen in the liquid phase area of the tank body, and after forced cooling, pumps it into the main guiding pipe.

[0011] As another optimized scheme of the above liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, a number of horizontal and vertical metal wire meshes are arranged inside the dispersion assembly. These metal wire meshes divide the inside of the dispersion assembly into several partitions, and the density of the porous medium filled in different partitions is different, so as to form a spray diversion channel between two adjacent partitions.

[0012] As another optimized scheme of the above liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, the porous medium is a silica macroporous material, its porosity is 50% - 70%, and the proportion of through pores is not less than 15%, and the maximum pore diameter does not exceed 1 mm.

[0013] As another optimization scheme for the above-mentioned low-turbulence liquid hydrogen storage tank for eliminating thermal stratification, a para-orthohydrogen conversion reactor is provided in the tank body, and the para-orthohydrogen conversion reactor includes a cylindrical shell with a solid para-orthohydrogen conversion catalyst filled therein, fins are distributed on the outer wall of the cylindrical shell, catalyst interception meshes are provided at both end openings of the cylindrical shell, and the two openings are respectively connected to an exhaust pipe and an intake pipe with an intake valve, the opening of the intake pipe is in the gas phase zone at the top of the tank body, the exhaust pipe is connected to the inlet of an exhaust coil provided in the insulation layer of the tank body, and the outlet of the exhaust coil is connected to an exhaust pipeline with an exhaust valve.

[0014] As another optimization scheme for the above-mentioned low-turbulence liquid hydrogen storage tank that eliminates thermal stratification, the tank body includes an outer shell and an inner shell arranged in the outer shell, and a vacuum layer is formed between the inner shell and the outer shell, and the surface of the inner shell is sequentially coated with a thermal insulation foam layer and a variable density insulation layer from the inside to the outside, and there is a gap between the variable density insulation layer and the outer shell.

[0015] As another optimization scheme for the above-mentioned low-turbulence liquid hydrogen storage tank that eliminates thermal stratification, the variable density insulation layer is formed by stacking and wrapping multiple layers of insulation materials with different densities, and the density of the insulation material gradually increases from the direction close to the inner shell to the outside.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The present invention provides a spray rod mechanism in the storage tank, and uses the guide pipe and the spreading assembly of the spray rod mechanism to spray liquid hydrogen directly onto the leaking hot spot, thereby reducing the turbulence of the liquid hydrogen in the tank and slowing down the evaporation of liquid hydrogen due to heat leakage; the core of the spreading assembly of the present invention is a porous medium, and the pore channels inside the porous medium and the pore channels formed between the porous media are used to make the sprayed liquid hydrogen flow as fine as possible and reduce the speed, while forming a "turbulent flow field" near the leaking hot spot, and cooling the leaking hot spot while reducing turbulence as much as possible to prevent the occurrence of thermal stratification; and by using a metal wire mesh to separate the spreading assembly into multiple independent partitions, each partition is filled with porous media of different densities, thereby further changing the flow state of liquid hydrogen when passing through the spreading mechanism, and further reducing the disturbance and turbulence of the overall liquid phase;

[0018] 2) Because liquid hydrogen storage tanks generally have an inner and outer double-layer structure, and the largest leaking hot spot is actually the supporting point of the inner tank body, the present invention transforms the inner wall of the tank body, and makes the inner wall of the tank body corresponding to the leaking hot spot into a rough area or a raised area with a roughness much greater than that of the other areas, so that the external heat can be gathered to the leaking hot spot and transferred into the tank body, and then cooled by the sprayed liquid hydrogen. Compared with the structure with a completely uniform and smooth inner wall, the cooling efficiency can be effectively improved;

[0019] 3) In the present invention, a para - normal hydrogen conversion reactor is arranged inside the tank body. By utilizing the para - hydrogen conversion reaction of the stored liquid hydrogen in the tank to absorb the heat inside the tank body, the para - hydrogen in the gas phase inside the tank body is converted into normal hydrogen, rapidly cooling the gas phase region at the top inside the tank body and reducing the pressure inside the storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 is a schematic diagram of the structure of the spray bar mechanism in the present invention;

[0022] Figure 3 is a schematic diagram of the structure of the dispersion assembly;

[0023] Figure 4 is a schematic diagram of the structure of the para - normal hydrogen conversion reactor;

[0024] Reference numerals: 1, tank body; 101, outer housing; 102, vacuum layer; 103, variable - density insulation layer; 104, thermal insulation foam layer; 105, inner housing; 106, exhaust coiled pipe; 107, heat leak point; 108, support; 2, spray bar mechanism; 201, main guiding pipe; 202, branch guiding pipe; 203, dispersion assembly; 204, wire mesh; 205, partition; 3, liquid hydrogen circulation pipeline; 301, circulation pump; 4, para - normal hydrogen conversion reactor; 401, cylindrical shell; 402, catalyst interception wire mesh; 403, fin; 404, intake valve; 405, intake pipe; 406, exhaust pipe; 5, exhaust pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be elaborated in detail below in combination with specific embodiments. For parts not clarified in the following embodiments of the present invention, such as the manufacture of the porous medium, the fixation of the inner tank in the inner and outer tank structures, the selection and coating of the thermal insulation material between the inner tank and the outer tank, the selection of the para - normal hydrogen conversion catalyst, etc., should be understood as the prior art known or should be known to those skilled in the art.

[0026] Embodiment 1

[0027] A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, as Figure 1 and Figure 2As shown in the figure, it includes a tank body 1 and a spray bar mechanism 2 arranged inside the tank body 1. Among them, the tank body 1 can adopt an existing tank body, and its affiliated heat preservation structure, fixed support structure, etc. all belong to the technologies known to those skilled in the art. The improvement point of the present invention does not lie in this, so it will not be elaborated here. After storing liquid hydrogen in the tank body 1, due to heat leakage, the liquid hydrogen will gradually vaporize and gradually form a gas phase region at the top inside the tank body 1. At the same time, the remaining regions inside the tank body 1 are liquid phase regions. When the pressure in the gas phase region exceeds the set pressure inside the tank body 1, it is necessary to exhaust and release the gas; the spray bar mechanism 2 is located in the liquid phase region. The essence of the spray bar mechanism 2 is a metal hollow rod-shaped structure. The spray bar mechanism 2 is connected to the liquid hydrogen circulation pipeline 3, so that the liquid hydrogen circulation pipeline 3 extracts the liquid hydrogen in the tank body 1 and sprays it onto the heat leakage point 107 through the spray bar mechanism 2. The core of the liquid hydrogen circulation pipeline 3 is to extract the liquid hydrogen in the liquid phase region of the tank body 1 through the circulation pump 301, cool it forcibly and then pump it into the spray bar mechanism 2, and directly spray it onto the heat leakage point 107 through the spray bar mechanism 2; as Figure 2 shown, the spray bar mechanism 2 includes a main guiding pipe 201 and a number of branch guiding pipes 202. There is one main guiding pipe 201, one end of which is connected to the liquid hydrogen circulation pipeline 3, and the other end is simultaneously connected to one end of all the branch guiding pipes 202, so as to divert the liquid hydrogen into each branch guiding pipe 202. A dispersion assembly 203 that fits the heat leakage point 107 is arranged at the end of the branch guiding pipe 202. The position of the branch guiding pipe 202 close to the dispersion assembly 203 is fixedly connected to a connecting piece, and the connecting piece is fixedly connected to the inner wall of the tank body 1, thereby realizing the fixation of the entire spray bar mechanism 2 inside the tank body 1. In practice, the end of the main guiding pipe 201 connected to the liquid hydrogen circulation pipeline 3 can also be fixed ( Figure 2 not shown in the figure). The dispersion assembly 203 is a structure surrounded by an elastic metal wire mesh, and a porous medium is filled inside. The porous medium is granular with different diameters and contains through channels inside. The mesh holes of the elastic metal wire mesh should be smaller than the particle size of the smallest particles of the porous medium to prevent the porous medium particles from being washed away, so that the liquid hydrogen is dispersed and sprayed onto the heat leakage point 107 through the porous medium, reducing the turbulence of the liquid hydrogen.

[0028] In this embodiment, the porous medium is a silica macroporous material, its porosity is 50% - 70%, and the proportion of the through channels is not less than 15%, and the maximum pore diameter does not exceed 1 mm.

[0029] In this embodiment, the heat leakage point 107 corresponds to the connection point of the support 108 of the tank body 1, that is, the external heat is mainly transferred to the inside of the tank body 1 through the connection point of the support 108.

[0030] The above is the basic implementation mode of the present invention. Further improvements, optimizations and limitations can be made on this basis to obtain the following embodiments:

[0031] Embodiment 2

[0032] This embodiment further defines the leakage hot spot 107. Its main structure is the same as that of Embodiment 1. The improvement lies in that: the leakage hot spot 107 mainly has the following two setting methods. One is distributed in the rough area of the inner wall of the tank body 1, and the surface roughness Ra of the rough area is ≥ 12.5, and the Ra of the rest of the inner wall area is ≤ 0.8; that is to say, when machining the inner wall of the tank body 1, the areas at the predetermined leakage hot spots 107 and other areas are machined with different precisions, and finally the above requirements are met.

[0033] Another structure is that the leakage hot spot 107 is a convex area distributed on the inner wall of the tank body 1, and the surface roughness Ra of the convex area is ≥ 12.5, and the Ra of the rest of the inner wall area is ≤ 0.8; in practice, the convex height of the convex area is generally 2 - 10 mm.

[0034] Embodiment 3

[0035] This embodiment is an improved solution for the dispersion component 203 in Embodiment 1. Its main structure is the same as that of Embodiment 1. The improvement lies in that: as Figure 3 shown, a number of horizontal and vertical wire meshes 204 are arranged in the dispersion component 203. These wire meshes 204 divide the inside of the dispersion component 203 into several partitions 205, and the compactness of the porous medium filled in different partitions 205 is different, so as to form a spraying diversion channel between two adjacent partitions 205.

[0036] Embodiment 4

[0037] This embodiment is an optimized solution for Embodiment 1. Its main structure is the same as that of Embodiment 1. The improvement lies in that: as Figure 1 and Figure 4As shown in the figure, a para - normal hydrogen conversion reactor 4 is provided in the gas phase region of the tank body 1. The para - normal hydrogen conversion reactor 4 includes a cylindrical shell 401 filled with solid para - normal hydrogen conversion catalyst inside. Fins 403 are distributed on the outer wall of the cylindrical shell 401. The fins 403 are annular metal sheets, and the metal sheets can be flat or corrugated plates, etc. They are distributed around the cylindrical shell 401, and multiple groups of fins 403 are distributed parallel to its axis for rapid refrigeration. Catalyst interception wire meshes 402 are provided at both open ends of the cylindrical shell 401 to prevent the solid para - normal hydrogen conversion catalyst from being carried by hydrogen, reducing the consumption of the para - normal hydrogen conversion catalyst and extending the catalyst replacement period. The catalyst interception wire mesh 402 is a low - temperature - resistant porous wire mesh, and its precision can be determined according to the size of the para - normal hydrogen conversion catalyst used, being smaller than the size of the para - normal hydrogen conversion catalyst. Two openings of the cylindrical shell 401 are respectively connected to an exhaust pipe 406 and an inlet pipe 405 with an inlet valve 404. The opening of the inlet pipe 405 is in the gas phase region at the top inside the tank body 1. The vaporized hydrogen enters the cylindrical shell 401 along the inlet pipe 405 to undergo a conversion reaction and absorb heat, thereby using the fins 403 to refrigerate the external gas phase. The converted hydrogen is then discharged from the exhaust pipe 406. The exhaust pipe 406 is connected to the inlet of an exhaust coiled pipe 106 provided in the thermal insulation layer of the tank body 1, and the outlet of the exhaust coiled pipe 106 is communicated with an exhaust pipeline 5 with an exhaust valve. The exhaust coiled pipe 106 is arranged in a surrounding manner in the thermal insulation layer of the tank body 1.

[0038] In this embodiment, when the pressure in the exhaust coiled pipe 106 reaches the set pressure, the exhaust valve on the exhaust pipeline 5 opens for exhaust. It should be noted that the pressure set value of the exhaust coiled pipe 106 is higher than the pressure set value of the liquid hydrogen storage tank.

[0039] In this embodiment, para - normal hydrogen conversion catalyst can also be filled in the exhaust coiled pipe 106, so that during the process of the gaseous hydrogen discharging along the exhaust coiled pipe 106, a secondary para - normal conversion reaction occurs, further releasing the cold energy of gaseous parahydrogen and maximizing the utilization of the cold energy carried by the externally exhausted hydrogen to resist external heat leakage.

[0040] Embodiment 5

[0041] This embodiment is another optimized solution of Embodiment 1. Its main structure is the same as that of Embodiment 1, and the improvement lies in: as Figure 1 shown, the tank body 1 includes an outer shell 101 and an inner shell 105 arranged inside the outer shell 101. The inner and outer shells are fixedly supported by brackets 108. A vacuum layer 102 is formed between the inner shell 105 and the outer shell 101. The surface of the inner shell 105 is sequentially coated with a thermal insulation foam layer 104 and a variable - density insulation layer 103 from the inside to the outside, and there is a gap between the variable - density insulation layer 103 and the outer shell 101. The thermal insulation foam layer 104 is a conventional cryogenic thermal insulation foam material, which is wrapped on the outer wall surface of the inner shell 105.

[0042] In this embodiment, the variable-density thermal insulation layer 103 is formed by stacking and covering multiple layers of thermal insulation materials with different densities, and the density of the thermal insulation materials gradually increases from the direction close to the inner shell 105 towards the outside.

[0043] Embodiment 6

[0044] This embodiment is the most preferred solution of the present invention. As Figure 1 shown, it includes a tank body 1 and a spray bar mechanism 2 arranged in the tank body 1. The spray bar mechanism 2 is communicated with the liquid hydrogen circulation pipeline 3, so that the liquid hydrogen circulation pipeline 3 extracts the liquid hydrogen in the tank body 1 and sprays it to the heat leakage point 107 through the spray bar mechanism 2. The core of the liquid hydrogen circulation pipeline 3 is to extract the liquid hydrogen in the liquid phase area of the tank body 1 through a circulation pump 301, and after forced cooling, pump it into the spray bar mechanism 2, and directly spray it to the heat leakage point 107 through the spray bar mechanism 2; as Figure 2 shown, the spray bar mechanism 2 includes a main guiding pipe 201 and a plurality of branch guiding pipes 202. There is one main guiding pipe 201, one end of which is communicated with the liquid hydrogen circulation pipeline 3, and the other end is simultaneously communicated with one end of all the branch guiding pipes 202, so as to divert the liquid hydrogen into each branch guiding pipe 202. A dispersion assembly 203 that fits the heat leakage point 107 is arranged at the end of the branch guiding pipe 202. The position of the branch guiding pipe 202 close to the dispersion assembly 203 is fixedly connected to a connecting piece, and the connecting piece is fixedly connected to the inner wall of the tank body 1, thereby realizing the fixation of the entire spray bar mechanism 2 in the tank body 1. In practice, the end of the main guiding pipe 201 connected to the liquid hydrogen circulation pipeline 3 can also be fixed ( Figure 2 not shown in the figure). The dispersion assembly 203 is a structure surrounded by an elastic metal wire mesh, and a porous medium is filled inside. The porous medium is in the shape of particles with different diameters and contains through channels inside. The mesh holes of the elastic metal wire mesh should be smaller than the particle size of the smallest particles of the porous medium to prevent the porous medium particles from being washed away, so that the liquid hydrogen is dispersed and sprayed onto the heat leakage point 107 through the porous medium, reducing the turbulence of the liquid hydrogen;

[0045] A para - normal hydrogen conversion reactor 4 is provided in the gas phase region of the tank body 1. The para - normal hydrogen conversion reactor 4 includes a cylindrical shell 401 filled with a solid para - normal hydrogen conversion catalyst inside. The outer wall of the cylindrical shell 401 is distributed with fins 403. The fins 403 are annular metal sheets, and the metal sheets can be flat or corrugated plates, etc. They are distributed around the cylindrical shell 401 and multiple groups of fins 403 are distributed parallel to its axis for rapid refrigeration. Catalyst interception wire meshes 402 are provided at both ends of the cylindrical shell 401 to prevent the solid para - normal hydrogen conversion catalyst from being carried by hydrogen, reducing the consumption of the para - normal hydrogen conversion catalyst and extending the catalyst replacement period. The catalyst interception wire mesh 402 is a low - temperature resistant porous wire mesh, and its precision can be determined according to the size of the para - normal hydrogen conversion catalyst used, being smaller than the size of the para - normal hydrogen conversion catalyst. The two openings of the cylindrical shell 401 are respectively connected to an exhaust pipe 406 and an inlet pipe 405 with an inlet valve 404. The opening of the inlet pipe 405 is in the gas phase region at the top inside the tank body 1. The vaporized hydrogen enters the cylindrical shell 401 along the inlet pipe 405 to undergo a conversion reaction and absorb heat, thereby using the fins 403 to refrigerate the external gas phase. The converted hydrogen is then discharged from the exhaust pipe 406, and the exhaust pipe 406 is connected to the inlet of an exhaust coil 106 provided in the thermal insulation layer of the tank body 1. The outlet of the exhaust coil 106 is communicated with an exhaust pipeline 5 with an exhaust valve;

[0046] The tank body 1 includes an outer shell 101 and an inner shell 105 provided inside the outer shell 101. The inner and outer shells are fixedly supported by brackets 108. A vacuum layer 102 is formed between the inner shell 105 and the outer shell 101. The surface of the inner shell 105 is sequentially coated with a thermal insulation foam layer 104 and a variable - density insulation layer 103 from the inside to the outside, and there is a gap between the variable - density insulation layer 103 and the outer shell 101. The thermal insulation foam layer 104 is a conventional cryogenic thermal insulation foam material and is wrapped on the outer wall surface of the inner shell 105. The exhaust coil 106 is arranged around the variable - density insulation layer 103;

[0047] The working process of this embodiment is as follows:

[0048] Under the suction of the circulation pump 301, liquid hydrogen enters the spray bar mechanism 2 from the tank body 1 through the liquid hydrogen circulation pipeline 3, passes through the main guiding pipe 201 and then is dispersed into each branch guiding pipe 202. After being divided by the dispersion assembly 203 at the end of the branch guiding pipe 202, it is atomized into small liquid droplets and directly sprayed onto the heat leakage point 107 inside the tank body 1. Under a small - range disturbance, relying on the sub - cooling degree of the liquid hydrogen itself, it can specifically eliminate local thermal stratification, reduce the influence of local heat leakage on the overall storage tank, and extend the storage time of liquid hydrogen;

[0049] After the supercooling degree of the liquid hydrogen itself is exhausted, it is no longer possible to reduce the pressure in the tank 1 only by the circulation of the liquid hydrogen circulation pipeline 3. At this time, the pressure in the tank 1 will slowly rise as the liquid hydrogen continues to evaporate and gasify. When the pressure in the tank 1 reaches the set value, the intake valve 404 opens, and gaseous hydrogen enters the para-to-ortho conversion reactor 4 for the para-to-ortho reaction to release cold energy. The cold energy is transferred to the gas phase in the tank 1 through the fins 403, cooling the gas phase in the tank 1, thereby reducing the pressure in the tank 1. When the pressure in the tank 1 is lower than the set value, the intake valve 404 closes;

[0050] The hydrogen after para-to-ortho conversion flows out of the para-to-ortho conversion reactor 4 and enters the exhaust coiled pipe 106. The exhaust coiled pipe 106 is located in the vacuum layer 102 and spirally wound around the outside of the variable density insulation layer 103. The low-temperature hydrogen forms a cold shield after flowing through the exhaust coiled pipe 106, isolating heat and slowing down the evaporation of the liquid hydrogen in the storage tank. The para-to-ortho conversion catalyst can be filled in the exhaust coiled pipe 106. At this time, the low-temperature hydrogen will undergo a secondary para-to-ortho conversion reaction when flowing through the exhaust coiled pipe 106, further releasing the cold energy of the gaseous para-hydrogen and maximizing the utilization of the cold energy carried by the exhaust hydrogen to resist external heat leakage; when the pressure in the exhaust coiled pipe 106 reaches the set value, the valve on the exhaust pipeline 5 connected to the end of the exhaust coiled pipe 106 opens, and the hydrogen is discharged through the exhaust pipeline 5. When the pressure in the exhaust coiled pipe 106 is lower than the set value, the exhaust pipeline 5 closes.

Claims

1. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence, comprising a tank body (1) and a spray bar mechanism (2) arranged inside the tank body (1). The spray bar mechanism (2) is communicated with a liquid hydrogen circulation pipeline (3), so that the liquid hydrogen circulation pipeline (3) extracts liquid hydrogen inside the tank body (1) and sprays it to the heat leakage point (107) through the spray bar mechanism (2), and is characterized in that: The spray bar mechanism (2) includes a main guiding pipe (201) and a plurality of branch guiding pipes (202). A cloth dispersion assembly (203) that fits with the leakage hot spot (107) is provided at the end of the branch guiding pipe (202). The cloth dispersion assembly (203) is a structure surrounded by an elastic metal wire mesh, and a porous medium is filled inside it, so that liquid hydrogen is dispersed and sprayed onto the leakage hot spot (107) through the porous medium, reducing the turbulence of liquid hydrogen.

2. The liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, wherein: The leakage hot spot (107) is a rough area distributed on the inner wall of the tank body (1), and the roughness Ra of the rough area is ≥ 12.5, while the Ra of the remaining areas of the inner wall is ≤ 0.

8.

3. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: The leakage hot spot (107) is a convex area distributed on the inner wall of the tank body (1), and the surface roughness Ra of the convex area is ≥ 12.5, while the Ra of the remaining areas of the inner wall is ≤ 0.

8.

4. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: The leakage hot spot (107) corresponds to the connection point of the support (108) of the tank body (1).

5. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: The liquid hydrogen circulation pipeline (3) has a circulation pump (301), and the circulation pump (301) extracts liquid hydrogen from the liquid phase area inside the tank body (1) and pumps it into the main guiding pipe (201).

6. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: A number of horizontal and vertical metal wire meshes (204) are arranged inside the cloth dispersion assembly (203). These metal wire meshes (204) divide the inside of the cloth dispersion assembly (203) into several partitions (205). The density of the porous medium filled in different partitions (205) is different, so as to form a spraying diversion channel between two adjacent partitions (205).

7. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: The porous medium is a silica macroporous material, its porosity is 50% - 70%, and the proportion of through pores is not less than 15%, and the maximum pore diameter does not exceed 1 mm.

8. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: A para - ortho hydrogen conversion reactor (4) is provided inside the tank body (1). The para - ortho hydrogen conversion reactor (4) includes a cylindrical shell (401) filled with a solid para - ortho hydrogen conversion catalyst inside. Fins (403) are distributed on the outer wall of the cylindrical shell (401). Catalyst interception wire meshes (402) are provided at both open ends of the cylindrical shell (401), and the two openings are respectively connected to an exhaust pipe (406) and an inlet pipe (405) with an inlet valve (404). The opening of the inlet pipe (405) is in the gas phase area at the top inside the tank body (1). The exhaust pipe (406) is connected to the inlet of an exhaust coil (106) provided in the thermal insulation layer of the tank body (1), and the outlet of the exhaust coil (106) is communicated with an exhaust pipeline (5) with an exhaust valve.

9. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: The tank body (1) includes an outer shell (101) and an inner shell (105) provided inside the outer shell (101). A vacuum layer (102) is formed between the inner shell (105) and the outer shell (101). The surface of the inner shell (105) is sequentially coated with a thermal insulation foam layer (104) and a variable - density thermal insulation layer (103) from the inside to the outside, and there is a gap between the variable - density thermal insulation layer (103) and the outer shell (101).

10. A liquid hydrogen storage tank for eliminating thermal stratification with low turbulence according to claim 1, characterized in that: The variable - density thermal insulation layer (103) is formed by stacking and coating multiple thermal insulation materials with different densities, and the density of the thermal insulation materials gradually increases from the direction close to the inner shell (105) to the outside.

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