A liquid hydrogen storage tank

Abstract

The present invention discloses a liquid hydrogen storage tank, which belongs to the technical field of liquid hydrogen storage tank equipment. The liquid hydrogen storage tank is a normal pressure vertical cylindrical bimetallic full-containment tank. The tank body of the liquid hydrogen storage tank includes an inner tank, an insulation layer and an outer tank arranged in sequence from the inside to the outside, wherein the insulation layer of the tank body of the liquid hydrogen storage tank includes a first vacuum insulation blanket layer, a liquid nitrogen cold shield layer and a first aerogel layer arranged in sequence from the inside to the outside, the first vacuum insulation blanket layer is a flexible cavity filled with fibers, and the cavity is evacuated into a vacuum; the first vacuum insulation blanket layer is fixedly arranged on the outer wall of the inner tank of the tank body, the liquid nitrogen cold shield layer is fixedly arranged on the first vacuum insulation blanket layer, and the first aerogel layer is filled between the liquid nitrogen cold shield layer and the outer tank of the tank body. The liquid hydrogen storage tank provided by the present invention does not need to withstand vacuum, and its daily evaporation rate can reach 0.13% / day. The inner and outer tanks can be realized and economically reasonable under the strength of existing materials, so that the liquid hydrogen storage tank can be large-scaled, and its volume can reach 10,000m 3 .

Description

Technical Field

[0001] The invention belongs to the technical field of liquid hydrogen storage tank equipment, and in particular relates to a liquid hydrogen storage tank. Background Art

[0002] Liquid hydrogen storage tanks are containers for storing liquid hydrogen, and they serve as a bridge from the production to the utilization of hydrogen. As a clean, safe, efficient and renewable energy source, hydrogen is one of the most effective energy sources for human clean energy utilization in the future. The world is currently experiencing the third major energy system transition from fossil energy to non-fossil energy such as hydrogen energy. Many governments have successively introduced supportive policies for the development of the hydrogen energy industry, prompting upstream and downstream enterprises and scientific research institutions in the hydrogen energy industry chain to work closely together to promote the rapid implementation of the hydrogen energy industry, which is mainly based on hydrogen fuel cell vehicles and distributed energy. Liquid hydrogen storage is a hydrogen storage technology that serves as a bridge from the production to the utilization of hydrogen, so safe and efficient hydrogen storage technology has become the key to the application of hydrogen energy. Moreover, with the expansion and popularization of hydrogen energy application fields, large-scale hydrogen storage is an inevitable development direction in the future.

[0003] The current hydrogen storage technologies mainly include: high pressure compression hydrogen storage technology, low temperature liquid hydrogen storage technology and chemical hydrogen storage technology. The performance parameters of hydrogen storage technology are mainly volume hydrogen storage density and mass hydrogen storage fraction. According to the goals proposed by the U.S. Department of Energy (DOE): the ultimate goal of hydrogen storage mass fraction is 7.5%, and the volume hydrogen storage density is 70kg / m 3 . Low-temperature liquid hydrogen storage has great advantages in transportation (especially long-distance transportation) and storage due to its high storage density. The storage and transportation of liquid hydrogen has developed with the development of rocket and aerospace engineering. At present, the United States, Russia, Japan, and France all have large liquid hydrogen storage tanks for rocket launches: for example, the National Aeronautics and Space Administration (NASA) uses a tank with a diameter of 25 meters and a volume of 3,800m 3 The spherical tanks are used to store liquid hydrogen; the rocket launch range is 1400m 3 Large spherical tank for liquid hydrogen; the volume of the liquid hydrogen spherical tank at the Tanegashima Space Center in Japan is 540m 3 At the same time, hydrogen liquefaction plants of a certain scale have been built in the civilian field in Europe and the United States, and horizontal cylindrical or vertical cylindrical pressure vessels are used to store liquid hydrogen. my country's low-temperature liquid hydrogen storage has been relatively maturely applied in aerospace engineering. By introducing foreign technology, a 1.5-ton / day liquid hydrogen device has been built, and it also has a 300m 3 And the following fixed and mobile horizontal cylindrical liquid hydrogen storage tank construction technology.

[0004] There are two types of liquid hydrogen storage tanks used in the above hydrogen storage technology. The first type is a pressurized cryogenic storage tank (with an internal pressure of 0.1-0.6 MPa). The pressurized cryogenic storage tank includes an inner tank and an outer tank, which are generally vertical or horizontal, cylindrical or spherical in shape. The interlayer between the inner tank and the outer tank is evacuated to achieve thermal insulation. This liquid hydrogen storage method has been relatively maturely applied in the aerospace and civil fields in Europe and the United States. However, due to the limitation of material strength and the difficulty and cost of obtaining and maintaining the vacuum degree between the interlayers, this type of pressurized cryogenic storage tank is generally only suitable for relatively low volumes (such as less than 4000m 3 The second type is the atmospheric low-temperature storage tank, which is mostly in the shape of a vertical cylindrical dome tank. This type of storage tank also includes an inner tank and an outer tank, which can store a large volume of low-temperature medium. For example, the current domestic liquefied natural gas (LNG) bimetallic full-containment tank has a maximum capacity of 80,000m 3 However, this vertical cylindrical bimetallic storage tank cannot withstand full vacuum, so the high vacuum multi-layer insulation or vacuum stacking insulation commonly used for liquid hydrogen media cannot be applied to this type of large tank.

[0005] Therefore, there is an urgent need for a large-capacity atmospheric-pressure liquid hydrogen storage tank that can meet the insulation requirements of liquid hydrogen and does not need to withstand a vacuum. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a liquid hydrogen storage tank, which has a large capacity and good thermal insulation performance and does not need to withstand vacuum.

[0007] The technical solution of the present invention is:

[0008] The present invention provides a liquid hydrogen storage tank, which is a normal pressure vertical cylindrical bimetallic full-containment tank. The tank body of the liquid hydrogen storage tank comprises an inner tank, an insulation layer and an outer tank which are sequentially arranged from the inside to the outside, wherein:

[0009] The insulation layer of the tank body of the liquid hydrogen storage tank includes a first vacuum insulation blanket layer, a liquid nitrogen cold shield layer and a first aerogel layer which are arranged in sequence from the inside to the outside. The first vacuum insulation blanket layer is a flexible cavity filled with fibers, and the cavity is evacuated. The first vacuum insulation blanket layer is fixedly arranged on the outer wall of the inner tank of the tank body, the liquid nitrogen cold shield layer is fixedly arranged on the first vacuum insulation blanket layer, and the first aerogel layer is filled between the liquid nitrogen cold shield layer and the outer tank of the tank body.

[0010] Furthermore, the thickness of the first vacuum insulation layer is 20-75 mm, and the vacuum pressure of the cavity of the first vacuum insulation layer is less than or equal to 10 -3 Pa.

[0011] Furthermore, the cavity of the first vacuum insulation blanket layer is made of any one of the following materials: aluminum foil composite fiber cloth, polymer film.

[0012] Furthermore, the liquid nitrogen cold shield layer includes a cold shield plate and a liquid nitrogen tube fixedly arranged on the cold shield plate, the cold shield plate is fixedly arranged on the first vacuum insulation blanket layer, and the liquid nitrogen tube is in contact with the first aerogel layer.

[0013] Furthermore, the first aerogel layer is obtained by stacking at least one of the following aerogels: silicon dioxide aerogel and carbide aerogel; and the thickness of the first aerogel layer is 800-1000 mm.

[0014] Furthermore, the insulation layer of the tank top of the liquid hydrogen storage tank includes a second vacuum insulation blanket layer and a second aerogel layer arranged in sequence from the inside to the outside, the second vacuum insulation blanket layer is connected to the inner tank of the tank top, and the second aerogel layer is filled between the outer tank of the tank top and the second vacuum insulation blanket layer; the insulation layer of the tank bottom of the liquid hydrogen storage tank includes fiberglass.

[0015] Furthermore, an inlet pipe and an outlet pipe are provided on the top of the liquid hydrogen storage tank, and the inlet pipe and the outlet pipe both include a first inner tube and a first outer tube sealed outside the first inner tube, a sealed cavity is formed between the first inner tube and the first outer tube, and the sealed cavity is a vacuum, and one end of the first inner tube and the first outer tube are inserted into the outer tank, the insulation layer and the inner tank in sequence and enter into the inner tank.

[0016] Furthermore, a bellows compensator is provided in the middle of the first outer tube.

[0017] Furthermore, a shell-and-tube para-orthohydrogen catalytic converter is arranged on the top of the liquid hydrogen storage tank, a para-orthohydrogen conversion catalyst is arranged in the tube-side heat exchange tube of the para-orthohydrogen catalytic converter, the tube-side inlet of the para-orthohydrogen catalytic converter is connected with the inlet pipe of the liquid hydrogen storage tank, the tube-side outlet of the para-orthohydrogen catalytic converter passes through the top of the liquid hydrogen storage tank and is connected with the inlet of the cryogenic cold box, and the shell-side outlet of the para-orthohydrogen catalytic converter passes through the top of the liquid hydrogen storage tank and is connected with the inlet of the cryogenic cold box.

[0018] Furthermore, the space between the inner tank and the outer tank is filled with hydrogen at a pressure of 15-30 KPa.

[0019] The beneficial effects of the present invention include at least:

[0020] The present invention provides a liquid hydrogen storage tank, the tank body of which includes an inner tank, an insulation layer and an outer tank from the inside to the outside, wherein the insulation layer of the tank body of the liquid hydrogen storage tank adopts a combined insulation method of a vacuum insulation blanket layer, a liquid nitrogen cold shield layer and an aerogel layer, wherein the vacuum insulation blanket layer and the aerogel layer can eliminate most of the gas convection heat transfer, and the liquid nitrogen cold shield layer can absorb most of the radiation heat from the external environment and take it away by the liquid nitrogen circulation conveying pipe, which can effectively block the radiation heat transfer, so that the liquid hydrogen storage tank has good insulation performance. According to calculations, the daily evaporation rate of the liquid hydrogen storage tank of this structure can reach 0.13% / day. Due to this combined insulation structure and normal pressure storage, there is no need to evacuate the inner tank and the outer tank, so that the inner and outer tanks can be realized and economically reasonable under the strength of existing materials, so that the liquid hydrogen storage tank can be large-scale, and its volume can reach 10,000m 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a liquid hydrogen storage tank provided in an embodiment of the present invention;

[0022] Figure 2 for Figure 1 Schematic diagram of the structure of the tank body and tank bottom of the medium liquid hydrogen storage tank;

[0023] Figure 3 It is a schematic diagram of the structure of the liquid nitrogen cold shield layer;

[0024] Figure 4 for Figure 3 Cross-section at AA in the middle;

[0025] Figure 5 for Figure 1 Schematic diagram of the structure of the middle outlet pipe;

[0026] Figure 6 for Figure 5 A partial enlarged view of

[0027] Figure 7 It is a schematic diagram of the structure of a shell-and-tube secondary orthohydrogen catalytic converter.

[0028] Figure 1-7 In the figure, 1-outer tank; 2-first aerogel layer; 3-liquid nitrogen pipe; 4-cold shield plate; 5-first vacuum insulation blanket layer; 6-inner tank; 7-glass fiber reinforced plastics; 8-concrete pedestal; 9-para-orthohydrogen catalytic converter, 901-tube side inlet, 902-tube side outlet, 903-shell side inlet, 904-shell side outlet; 10-inlet pipe; 11-catalyst; 12-outlet pipe, 1201-first inner pipe, 1202-first outer pipe, 1203-bellows compensator; 13-second aerogel layer; 14-second vacuum insulation blanket layer. DETAILED DESCRIPTION

[0029] In order to enable technicians in the technical field to which the present application belongs to understand the present application more clearly, the technical solution of the present application is described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0030] For liquid hydrogen medium, due to its low density (only 70kg / m 3 ), and the temperature difference with the environment is large, so at the same ambient temperature, liquid hydrogen is easier to evaporate than liquefied natural gas, and the evaporation rate of liquid hydrogen is about 10 times that of LNG. Therefore, a form similar to liquefied natural gas bimetallic full containment tank is used to store liquid hydrogen. Due to its single pearl sand stack insulation, the evaporation rate of liquid hydrogen is too high and is not applicable.

[0031] Figures 1 to 7 A schematic diagram of the structure of a liquid hydrogen storage tank provided in an embodiment of the present invention, combined with Figures 1 to 7 , an embodiment of the present invention provides a liquid hydrogen storage tank.

[0032] Combination Figure 1 The liquid hydrogen storage tank provided in this embodiment is a normal pressure vertical cylindrical bimetallic full-containment tank, which includes an inner tank 6, an insulation layer and an outer tank 1 arranged in sequence from the inside to the outside.

[0033] Specific, combined Figure 2 The insulation layer of the tank body of the liquid hydrogen storage tank may include a first vacuum insulation blanket layer 5, a liquid nitrogen cold shield layer and a first aerogel layer 2 which are arranged in sequence from the inside to the outside. The first vacuum insulation blanket layer 5 is a flexible cavity filled with fibers, and the cavity is evacuated. The first vacuum insulation blanket layer 5 is fixedly arranged on the outer wall of the inner tank 6 of the tank body, the liquid nitrogen cold shield layer is fixedly arranged on the first vacuum insulation blanket layer 5, and the first aerogel layer 2 is filled between the liquid nitrogen cold shield layer and the outer tank 1 of the tank body.

[0034] The functions of each layer in the thermal insulation layer of the liquid hydrogen storage tank are as follows:

[0035] First vacuum insulation quilt layer 5: Because there is no air in the first vacuum insulation quilt layer 5, most of the convective heat transfer can be blocked. The filling fiber has a low thermal conductivity on the one hand, and can also play a role in supporting the flexible vacuum cavity on the other hand, so that the vacuum insulation quilt can be arbitrarily matched with the shape of the inner tank 6. If the first vacuum insulation quilt layer 5 is set on the inner wall of the outer tank of the tank body, the temperature difference between the temperature at the inner tank 6 from -253°C to the ambient temperature at the outer tank 1 will be large, resulting in an increase in the required thickness of the first aerogel layer 2 and a large amount of aerogel filling, thereby increasing the construction cost of the storage tank; on the contrary, the first vacuum insulation quilt layer 5 is set on the outer wall of the inner tank, so that the temperature passes through the first vacuum insulation quilt layer 5 from -253°C at the inner tank to -196°C close to liquid nitrogen, so that the temperature difference that the first aerogel layer 2 needs to withstand is small, and the thickness required for the first aerogel layer 2 is small. If the first vacuum insulation quilt layer 5 is set inside the first aerogel layer 2, the first vacuum insulation quilt layer 5 cannot be supported and cannot be realized. In actual operation, a cylindrical thin stainless steel plate can be arranged outside the first vacuum insulation blanket layer 5 to wrap the vacuum insulation blanket. In addition, the steel plate can also be used as a cold shield plate for liquid nitrogen cold shield. In the embodiment of the present invention, the filling fiber in the first vacuum insulation blanket layer 5 can be glass fiber, chemical fiber, etc., without specific limitation.

[0036] Liquid nitrogen cold shield layer: Since the liquid nitrogen cold shield layer can be fed with low-temperature (-196°C) liquid nitrogen, it can take away most of the heat from the radiation heat transfer in the environment, thereby preventing the radiation heat transfer. If the liquid nitrogen cold shield layer is set on the inner wall of the outer tank 1 of the tank body, the temperature of the inner wall of the outer tank 1 will be reduced to a very low level. The water vapor in the air on the outer wall of the outer tank will encounter the low-temperature outer tank 1, and condense and freeze on the surface of the tank wall; if the liquid nitrogen cold shield layer is set in the middle of the first aerogel layer 2, from the temperature gradient, the temperature change from the inner tank to the liquid nitrogen cold shield layer is -253°C to -196°C, and the temperature change from the liquid nitrogen cold shield layer to the outer tank is -196°C to the ambient temperature. This arrangement is shorter than the arrangement of this case because the distance from the liquid nitrogen cold shield layer to the outer tank is shorter. Under the same temperature difference (-196°C to the ambient temperature), in order to obtain the same insulation effect as the embodiment of the present invention, the liquid nitrogen cold shield tubes need to be arranged more densely and the liquid nitrogen tubes need to be larger, which is not conducive to energy saving and cost reduction.

[0037] The first aerogel layer 2: The first aerogel layer 2 is a heat-insulating layer formed by stacking aerogel powder, which is arranged between the liquid nitrogen cold shield layer and the outer tank 1 of the tank body. The nanoporous network structure of the aerogel powder enables it to effectively eliminate most of the gas convection heat transfer.

[0038] Further, in the embodiment of the present invention, the thickness of the first vacuum insulation layer 5 can be 20-75 mm, and the vacuum pressure of the cavity of the first vacuum insulation layer 5 should be less than or equal to 10 -3Pa. The first vacuum insulation quilt layer 5 of this thickness can ensure the thermal insulation performance of the liquid hydrogen storage tank. In actual operation, the first vacuum insulation quilt layer 5 can be obtained by stacking multiple flexible cavities filled with fibers in the thickness direction, such as 2 layers, of course, it can also be 3 layers, and they can be stacked with staggered seams, so that the leakage hot spots between any two adjacent cavities can be covered to improve the thermal insulation effect. The vacuum insulation quilt layer can also use adhesives to stick multiple flexible cavities to the outer surface of the inner tank, and the specific number of layers can be flexibly adjusted as needed. If the first vacuum insulation quilt layer 5 is too thick, the insulation effect will be limited, and it will increase the material cost and installation cost, which is not economical; if the first vacuum insulation quilt layer is too thin, the insulation effect is not good.

[0039] Specifically, in the embodiment of the present invention, the cavity of the first vacuum insulation layer 5 can be made of any of the following materials: aluminum foil composite fiber cloth, polymer film. The aluminum foil composite fiber cloth has the characteristics of enhanced reflection, smooth and flat surface, large longitudinal and transverse tensile strength, airtightness, watertightness, and good sealing performance, so it can ensure the vacuum environment in the cavity. At the same time, the enhanced reflective aluminum foil can also prevent radiation heat transfer, so that it has good insulation performance.

[0040] More specifically, combined Figure 3 as well as Figure 4 In an embodiment of the present invention, the liquid nitrogen cold shield layer may include a liquid nitrogen tube 3 and a cold shield plate 4. The liquid nitrogen tube 3 is welded to the cold shield plate 4 by brazing. The cold shield plate 4 may be a cylindrical thin stainless steel plate fixed on the outside of the first vacuum insulation layer 5. The highest point height of the cold shield plate 4 may be the height of the liquid hydrogen level in the inner tank 6. The liquid nitrogen tube 3 is in contact with the first aerogel layer 2. There is liquid nitrogen in the liquid nitrogen tube 3. The temperature of the liquid nitrogen is low. The radiation heat of the external environment can be absorbed and taken away by the liquid nitrogen circulation in the liquid nitrogen tube 3. This can reduce the radiation heat transfer of the environment and ensure the insulation effect of the liquid hydrogen storage tank. In order to improve the effect, the liquid nitrogen tube 3 can be densely arranged relative to each other. For example, the distance between adjacent liquid nitrogen tubes is about 1000 mm. The diameter of the liquid nitrogen tube can be 1 inch. Its material can be selected from red copper with high thermal conductivity, or other materials with high thermal conductivity, which are not specifically limited here.

[0041] More specifically, in an embodiment of the present invention, the first aerogel layer 2 can be obtained by stacking at least one of the following aerogel powders: silicon dioxide aerogel, carbide aerogel, wherein the carbide aerogel can be selected from any one of silicon carbide aerogel and boron carbide aerogel, and of course other aerogels can be selected as needed. Aerogel has a nanoporous network structure, which can effectively eliminate most of the air convection heat transfer. The combination of the first aerogel layer 2 and the first vacuum insulation blanket layer 5 can eliminate most of the air convection heat transfer and conduction heat transfer, and can also eliminate a small part of the radiation heat transfer.

[0042] Furthermore, in an embodiment of the present invention, the thickness of the first aerogel layer 2 can be 800-1000 mm. Aerogel layers of this thickness have good thermal insulation effects on the one hand, and are also easy to construct on the other hand. If the thickness of the aerogel layer is too small, construction cannot be performed (i.e., people must be able to enter the space between the inner and outer tanks for construction), and the thermal insulation effect is poor; if the thickness of the aerogel layer is too large, the aerogel layer filling amount will be large, and the thermal insulation effect will not be significantly improved, resulting in high costs.

[0043] Combination Figure 1 In this embodiment, the insulation layer of the tank top of the liquid hydrogen storage tank may include a second vacuum insulation blanket layer 14 and a second aerogel layer 13 from the inside to the outside, wherein the second vacuum insulation blanket layer 14 is connected to the inner tank 6 of the tank top, and the second aerogel layer 14 is filled between the outer tank 1 of the tank top and the second vacuum insulation blanket layer 14; since the liquid hydrogen level line in the liquid hydrogen storage tank is lower than the tank top, the inside of the tank top is not in direct contact with the liquid hydrogen, and the temperature inside the tank top is higher than the temperature of the liquid hydrogen, so in order to ensure the insulation effect and balance the cost, the insulation layer of the tank top may not be provided with a liquid nitrogen cold shield layer. The second vacuum insulation blanket layer 14 may be set as a vacuum insulation blanket with the same filler and the same cavity as the first vacuum insulation blanket layer 5, and the second aerogel layer 13 may also use the same filler as the first aerogel layer 2.

[0044] In this embodiment, the insulation layer of the bottom of the liquid hydrogen storage tank may include fiberglass 7. Specifically, the fiberglass 7 with high strength and low thermal conductivity and a high-strength rigid polyurethane ring beam may be combined to support the weight load of the entire inner tank 6. At the same time, the contact heat conduction between the bottom of the inner tank 6 and the bottom of the outer tank 1 may be reduced to a minimum level.

[0045] Combine 5 and Figure 6 In this embodiment, the top of the liquid hydrogen storage tank may be provided with an inlet pipe 10 and an outlet pipe 12, and both the inlet pipe 10 and the outlet pipe 12 may include a first inner tube 1201 and a first outer tube 1202 that is sealed and sleeved outside the first inner tube 1201, so that a sealed cavity may be formed between the first inner tube 1201 and the first outer tube 1202, and the sealed cavity may be a vacuum to prevent convective heat transfer of air, so as to improve the insulation performance and the insulation effect of the liquid hydrogen storage tank. In addition, the first inner tube 1201 and the first outer tube 1202 are sequentially inserted into the outer tank 1, the insulation layer and the inner tank 6 to enter the inner tank. In addition, both the first inner tube 1201 and the first outer tube 1202 may be inner extension tubes. In addition, in order to convert orthohydrogen into parahydrogen, an ortho-parahydrogen conversion catalyst 11 may be placed in the inlet tube 10.

[0046] Specific, combined Figure 5 and Figure 6A bellows compensator 1203 may be provided in the middle of the first outer tube 1202 to compensate for thermal expansion and contraction. The bellows compensator 1203 is welded to the outer tube 1202; in addition, a glass fiber reinforced plastic thermal resistor may be provided at the connection between the first inner tube 1201 and the first outer tube 1202 to reduce heat conduction.

[0047] Furthermore, in the embodiment of the present invention, considering that parahydrogen accounts for more than 99% of the parahydrogen in the equilibrium state of parahydrogen and orthohydrogen in the liquid hydrogen storage tank at low temperature, since the conversion of orthohydrogen into parahydrogen is an exothermic process, the conversion of parahydrogen into orthohydrogen under the action of a catalyst is an endothermic process, so the boil-off gas (BOG) of the liquid hydrogen tank can be pre-cooled by means of this process to achieve the recovery of cold, and at the same time, the BOG can be recycled to achieve long-term low-loss storage of the liquid hydrogen storage tank. To this end, a shell-and-tube para-orthohydrogen catalytic converter 9 is set in the gas phase space of the inner tank 6 of the liquid hydrogen storage tank, and the para-orthohydrogen catalytic converter 9 can be supported by the support rods of the inner tank 6, such as Figure 1 shown.

[0048] Combination Figure 7 In the embodiment, a para-ortho-hydrogen conversion catalyst is arranged in the tube-side heat exchange tube of the para-ortho-hydrogen catalytic converter 9, the tube-side inlet 901 of the para-ortho-hydrogen catalytic converter 9 is connected with the inlet pipe 10 of the liquid hydrogen storage tank, the tube-side outlet 902 of the para-ortho-hydrogen catalytic converter 9 passes through the top of the liquid hydrogen storage tank and is connected with the inlet of the deep cold box, and the shell-side outlet 904 of the para-ortho-hydrogen catalytic converter 9 passes through the top of the liquid hydrogen storage tank and is connected with the inlet of the deep cold box. A stream of liquid hydrogen containing more than 99% para-hydrogen is introduced into the tube-side inlet of the para-ortho-hydrogen catalytic converter 9 by the liquid hydrogen inlet pipe 10, and the tubes in the tube-side are filled with para-ortho-hydrogen conversion catalyst. Under the action of the catalyst, the para-hydrogen is partially converted into ortho-hydrogen and absorbs heat; the BOG in the gas phase space of the liquid hydrogen tank is countercurrently heat-exchanged with the tube-side medium through the heat exchange tube under the action of the pressure difference through the shell-side suction port of the para-ortho-hydrogen catalytic converter 9, thereby realizing partial condensation of the BOG gas. The gas-liquid two-phase hydrogen after the shell side part condensation is returned to the inlet of the cryogenic cold box through the pipeline, and the mixed liquid hydrogen converted into orthohydrogen in the tube side part is also returned to the inlet of the cryogenic cold box. The two streams of medium continue to be cryogenically cooled in the cryogenic cold box and are converted into liquid hydrogen containing more than 99% of parahydrogen through multi-stage orthohydrogen and returned to the storage tank. The parahydrogen catalytic converter 9 can adopt a shell-and-tube heat exchanger in the prior art, which has a shell side inlet 903, a shell side outlet 904, a tube side inlet 901 and a tube side outlet 902. For example, the heat exchanger disclosed in the patent application with publication number CN103486883A can be selected. Of course, any shell-and-tube heat exchanger that can realize the function of the present invention can also be selected, and no specific limitation is made here.

[0049] Furthermore, in order to prevent the moisture in the air in the interlayer between the inner tank 6 and the outer tank 1, i.e., the insulation layer, from condensing and freezing at low temperatures, thereby affecting the insulation performance of the insulation structure, dry hydrogen with a slight positive pressure of 15-30 kPa can be filled in the interlayer between the inner and outer tanks. The liquid hydrogen storage tank provided by the present invention can be arranged on a concrete cap 8.

[0050] Furthermore, the inner tank 6 and the outer tank 1 can be made of austenitic stainless steel. In the present invention, the stainless steel can be S31603, with a tensile strength of ≥480 MPa. The specific type of stainless steel can be selected according to actual needs and is not specifically limited here.

[0051] To prevent the inner tank 6 and the outer tank 1 from becoming unstable, a compression ring structure may be provided between the tank top and the tank wall of the inner tank 6 and the outer tank. In an embodiment of the present invention, the liquid hydrogen storage tank may be a vertical cylindrical bimetallic full containment tank, that is, the tank top of the liquid hydrogen storage tank is a fixed dome structure, the lower part of the liquid hydrogen storage tank is a flat-bottomed cylinder, and the distance between the inner tank 6 and the outer tank 1 is about 800-1100 mm.

[0052] The present invention adopts a fiber-filled vacuumed flexible cavity as the first vacuum insulation layer 5, with a liquid nitrogen cold shield layer and a first aerogel layer 2. From the temperature gradient point of view, the temperature of the liquid hydrogen in the inner tank is -253°C, passing through the first vacuum insulation layer 5 to the liquid nitrogen cold shield layer -196°C (i.e. the temperature of liquid nitrogen, i.e. the temperature of the cold shield), and the temperature from the liquid nitrogen cold shield layer to the outer tank through the first aerogel layer 2 changes from -196°C to the ambient temperature, which conforms to the distribution of the temperature gradient. The first vacuum insulation layer 5, the liquid nitrogen cold shield layer and the first aerogel layer 2 are combined to provide the liquid hydrogen storage tank with good insulation performance. According to calculations, the daily evaporation rate of the liquid hydrogen storage tank of this structure is 0.13% / day; due to the characteristics of this combined insulation structure and normal pressure storage and no need for vacuuming between the inner and outer tanks, the inner and outer tanks can be realized and economically reasonable under the strength of existing materials, so that the liquid hydrogen storage tank can be large-scaled, and its volume can reach 10,000m 3 Based on the experience and data accumulated during the operation of this liquid hydrogen storage tank, the liquid hydrogen storage tank can be expanded to a larger volume in the future, such as 50,000m 3 , even 80000m 3 .

[0053] A liquid hydrogen storage tank provided by the present invention will be described in detail below in conjunction with specific embodiments.

[0054] Example 1

[0055] Example 1 provides a volume of 10000m 3The vertical cylindrical bimetallic full-capacity liquid hydrogen storage tank is fixedly arranged on a high pile concrete pedestal. The liquid hydrogen storage tank can adopt a vertical cylindrical bimetallic full-capacity tank, that is, the tank top of the liquid hydrogen storage tank is a fixed vault, and the lower part of the liquid hydrogen storage tank is a flat-bottomed cylinder. The liquid hydrogen storage tank includes an inner tank, an insulation layer and an outer tank from the inside to the outside.

[0056] The diameter of the lower cylindrical part of the inner tank is 28000mm, the tank wall height of the inner tank is 17900mm, the inner radius of the inner tank dome spherical shell is R22400mm, the material of the inner tank is austenitic stainless steel S31603, the design temperature is -253℃, and the design pressure is a slight positive pressure of 30kPa; the diameter of the lower cylindrical part of the outer tank is 30000mm, the tank wall height of the outer tank is 21000mm, the inner radius of the outer tank dome spherical shell is R24000mm, the material of the outer tank is also austenitic stainless steel S31603, the design pressure is a slight positive pressure of 20kpa, and the operating liquid level height of liquid hydrogen is 16900mm.

[0057] The insulation layer of the cylindrical part includes a vacuum insulation blanket layer, a liquid nitrogen cold shield layer and an aerogel layer which are arranged in sequence from the inside to the outside, wherein the vacuum insulation blanket layer is composed of a cavity made of aluminum foil composite fiber cloth filled with glass fiber, the cavity is evacuated, the thickness of a single-layer vacuum insulation blanket is 25 mm, the vacuum pressure of the vacuum insulation blanket is 0.001 Pa, and the cavity is staggered and stacked in the thickness direction of the cavity to form a vacuum insulation blanket layer with a thickness of 75 mm; the aerogel layer is formed by stacking silica aerogel, and the thickness of the aerogel layer is 1000 mm.

[0058] The heat insulating layer of the dome ball part comprises a vacuum heat insulating blanket layer and an aerogel layer which are sequentially arranged from the inside to the outside, wherein the vacuum heat insulating blanket layer and the aerogel layer are the same as those of the cylindrical part.

[0059] Example 2

[0060] Example 2 provides a liquid hydrogen storage tank, which is different from Example 1 in that: the volume of the liquid hydrogen storage tank is 5000 cubic meters, the diameter of the lower cylindrical part of the inner tank is 22500mm, the tank wall height of the inner tank is 16000mm, the inner radius of the inner tank dome spherical shell is R18000mm, the diameter of the lower cylindrical part of the outer tank is 24500mm, the tank wall height of the outer tank is 19000mm, the inner radius of the outer tank dome spherical shell is R19600mm, and the operating liquid level height of the liquid hydrogen is 14000mm.

[0061] The thickness of the single-layer vacuum insulation quilt is 10 mm, and the total thickness of the vacuum insulation quilt is 20 mm.

[0062] Example 3

[0063] Example 3 provides a liquid hydrogen storage tank, which is different from Example 1 in that: the volume of the liquid hydrogen storage tank is 8000 cubic meters, the diameter of the lower cylindrical part of the inner tank is 26000mm, the tank wall height of the inner tank is 18700mm, the inner radius of the inner tank dome spherical shell is R20800mm, the diameter of the lower cylindrical part of the outer tank is 28000m, the tank wall height of the outer tank is 21700mm, the inner radius of the outer tank dome spherical shell is R22400mm, and the operating liquid level height of liquid hydrogen is 16000mm.

[0064] The thickness of the single-layer vacuum insulation quilt is 15 mm, and the total thickness of the vacuum insulation quilt is 45 mm.

[0065] Comparative Example 1

[0066] Comparative Example 1 provides a liquid hydrogen storage tank with a volume of 10000m 3 The liquid hydrogen storage tank includes an inner tank, an insulation layer and an outer tank from the inside to the outside. The insulation layer is only formed by the accumulation of pearlescent sand. The thickness of the insulation layer is 1000 mm. The size and shape of the inner tank and the outer tank are the same as those in Example 1.

[0067] Comparative Example 2

[0068] Comparative Example 2 provides a liquid hydrogen storage tank. Taking Comparative Example 1 as a reference, Comparative Example 2 is different from Comparative Example 1 in that the insulation layer is formed by stacking silica aerogel, and the rest is the same as Comparative Example 1.

[0069] Comparative Example 3

[0070] Comparative Example 3 provides a liquid hydrogen storage tank. Taking Example 1 as a reference, the difference between the liquid hydrogen storage tank and Example 1 is that the insulation layer is composed of an aerogel layer and a liquid nitrogen cold shield layer, and the liquid nitrogen cold shield layer is arranged in the middle of the aerogel.

[0071] Comparative Example 4

[0072] Comparative Example 4 provides a liquid hydrogen storage tank, which is different from Example 1 in that the insulation layer is composed of a vacuum insulation blanket layer with a thickness of 20 mm and an aerogel layer composed of silica aerogel with a thickness of 800 mm from the inside to the outside.

[0073] Comparative Example 5

[0074] Comparative Example 5 provides a liquid hydrogen storage tank, which is different from Example 1 in that the insulation layer is composed of a vacuum insulation blanket layer with a thickness of 75 mm and an aerogel layer composed of silica aerogel with a thickness of 1000 mm from inside to outside.

[0075] The daily evaporation rate of the liquid hydrogen tanks provided in Examples 1-3 and Comparative Examples 1-5 was statistically analyzed during operation, and the comprehensive thermal conductivity of the liquid hydrogen storage tank (the average thermal conductivity of the insulation layer of the bottom, top and body of the liquid hydrogen storage tank) was calculated, as shown in Table 1.

[0076] Table 1

[0077]

[0078] It can be seen from the data in Table 1 that the comprehensive thermal conductivity of the insulation layer of the liquid hydrogen storage tank provided in Examples 1-3 is 0.0105-0.0222 Kca / (mhK), and the daily evaporation rate is 0.1358-0.4163%.

[0079] In Comparative Example 1, the liquid hydrogen storage tank has an insulation layer with pearl sand deposited in the cylindrical portion. The comprehensive thermal conductivity of the insulation layer of the liquid hydrogen storage tank is 0.5907 Kca / (mhK), and the daily evaporation rate is 7.6618%, which is much higher than that of the embodiment of the present invention.

[0080] In Comparative Example 2, the cylindrical portion of the liquid hydrogen storage tank has an insulation layer formed by stacking silica aerogel. The comprehensive thermal conductivity of the insulation layer of the liquid hydrogen storage tank is 0.5692 Kca / (mhK), and the daily evaporation rate is 7.3829%, which is also much higher than that of the embodiment of the present invention.

[0081] In Comparative Example 3, the cylindrical portion of the liquid hydrogen storage tank uses an aerogel layer and a liquid nitrogen cold shield layer as an insulation layer. The comprehensive thermal conductivity of the insulation layer of the liquid hydrogen storage tank is 0.0558 Kca / (mhK), and the daily evaporation rate is 0.7238%, which is also much higher than that of the embodiment of the present invention.

[0082] In Comparative Example 4, the cylindrical portion of the liquid hydrogen storage tank uses a vacuum insulation blanket layer and a silica aerogel layer as an insulation layer. The comprehensive thermal conductivity of the liquid hydrogen storage tank is 0.5669 Kca / (mhK), and the daily evaporation rate is 7.3531%, which is also much higher than that of the embodiment of the present invention.

[0083] In Comparative Example 5, the cylindrical vacuum insulation layer is 75 mm from the inside to the outside and the aerogel layer is 1000 mm thick and composed of silica aerogel. The comprehensive thermal conductivity of the liquid hydrogen storage tank is 0.5606 Kca / (mhK), and the daily evaporation rate is 7.2713%, which is also much higher than that of the embodiment of the present invention.

[0084] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0085] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A liquid hydrogen storage tank, which is a normal pressure vertical cylindrical bimetallic full-containment tank, and the tank body of the liquid hydrogen storage tank comprises an inner tank, an insulation layer and an outer tank arranged in sequence from the inside to the outside, characterized in that: The thermal insulation layer of the tank body of the liquid hydrogen storage tank comprises a first vacuum thermal insulation layer, a liquid nitrogen cold shield layer and a first aerogel layer which are sequentially arranged from the inside to the outside, wherein the first vacuum thermal insulation layer is a flexible cavity filled with fibers, and the cavity is evacuated; The first vacuum insulation layer is fixedly arranged on the outer wall of the inner tank of the tank body, the liquid nitrogen cold shield layer is fixedly arranged on the first vacuum insulation layer, and the first aerogel layer is filled between the liquid nitrogen cold shield layer and the outer tank of the tank body, so as to enlarge the liquid hydrogen storage tank.

2. A liquid hydrogen storage tank according to claim 1, characterized in that: The thickness of the first vacuum insulation layer is 20-75 mm, and the cavity vacuum pressure of the first vacuum insulation layer is less than or equal to 10 -3 Pa.

3. A liquid hydrogen storage tank according to claim 1, characterized in that: The cavity of the first vacuum insulation layer is made of any one of the following materials: aluminum foil composite fiber cloth, polymer film.

4. A liquid hydrogen storage tank according to claim 1, characterized in that: The liquid nitrogen cold shield layer comprises a cold shield plate and a liquid nitrogen tube fixedly arranged on the cold shield plate. The cold shield plate is fixedly arranged on the first vacuum insulation blanket layer, and the liquid nitrogen tube is in contact with the first aerogel layer.

5. A liquid hydrogen storage tank according to claim 1, characterized in that: The first aerogel layer is prepared by stacking at least one of the following aerogels: silicon dioxide aerogel and carbide aerogel; the thickness of the first aerogel layer is 800-1000 mm.

6. A liquid hydrogen storage tank according to claim 1, characterized in that: The insulation layer of the tank top of the liquid hydrogen storage tank includes a second vacuum insulation blanket layer and a second aerogel layer arranged in sequence from the inside to the outside, the second vacuum insulation blanket layer is connected to the inner tank of the tank top, and the second aerogel layer is filled between the outer tank of the tank top and the second vacuum insulation blanket layer; the insulation layer of the tank bottom of the liquid hydrogen storage tank includes fiberglass.

7. A liquid hydrogen storage tank according to claim 1, characterized in that: An inlet pipe and an outlet pipe are provided on the top of the liquid hydrogen storage tank, and the inlet pipe and the outlet pipe both include a first inner tube and a first outer tube sealed outside the first inner tube, a sealed cavity is formed between the first inner tube and the first outer tube, and the sealed cavity is a vacuum, and one end of the first inner tube and the first outer tube are inserted into the outer tank, the insulation layer and the inner tank in sequence and enter into the inner tank.

8. A liquid hydrogen storage tank according to claim 7, characterized in that: A bellows compensator is arranged in the middle of the first outer tube.

9. A liquid hydrogen storage tank according to claim 7, characterized in that: A shell-and-tube para-orthohydrogen catalytic converter is arranged at the top of the liquid hydrogen storage tank, a para-orthohydrogen conversion catalyst is arranged in the tube-side heat exchange tube of the para-orthohydrogen catalytic converter, the tube-side inlet of the para-orthohydrogen catalytic converter is connected with the inlet pipe of the liquid hydrogen storage tank, the tube-side outlet of the para-orthohydrogen catalytic converter passes through the top of the liquid hydrogen storage tank and is connected with the inlet of the deep cold box, and the shell-side outlet of the para-orthohydrogen catalytic converter passes through the top of the liquid hydrogen storage tank and is connected with the inlet of the deep cold box.

10. A liquid hydrogen storage tank according to claim 1, characterized in that: The space between the inner tank and the outer tank is filled with hydrogen gas at a pressure of 15-30 KPa.

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