Liquid hydrogen storage tank device utilizing vertical radiation refrigeration and multi-layer heat insulation

Abstract

The invention discloses a liquid hydrogen storage tank device utilizing vertical radiation refrigeration and multi-layer heat insulation. Wherein the liquid hydrogen storage device, the spraying foam heat insulation layer, the variable-density multi-layer heat insulation layer and the vertical radiation refrigeration layer are sequentially arranged from inside to outside; the steam cooling shield is clamped in the middle of the variable-density multi-layer heat insulation layer, is connected with the liquid hydrogen storage device through a pipeline, and uses hydrogen generated by evaporation of liquid hydrogen in the liquid hydrogen storage device as a cooling medium; the vertical radiation refrigeration layer comprises a substrate on the inner side and a film coating on the outer side. Vertical radiation refrigeration is added on the basis of original multi-layer heat insulation, heat entering is reduced through vertical radiation refrigeration, and therefore evaporation loss in the storage tank is additionally reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-pressure containers with heat insulation measures for containing or storing liquefied gas, and specifically is a liquid hydrogen storage tank device utilizing vertical radiation refrigeration and multi-layer heat insulation. Background Art

[0002] The structure of liquid hydrogen storage tanks generally adopts spherical storage tanks or cylindrical storage tanks. Liquid hydrogen has an extremely low boiling point, small latent heat of vaporization, and is very easy to evaporate. The storage conditions are relatively harsh. The temperature difference between liquid hydrogen and the environment is very large, so liquid hydrogen storage requires an insulation form with excellent insulation performance. There are two main technologies for reducing heat leakage: active insulation and passive insulation.

[0003] Active adiabatic technologies mainly include expansion refrigeration technology (using the adiabatic expansion effect of gas to lower the temperature and continuously remove heat through refrigeration units), helium refrigeration system (using the high-efficiency low-temperature characteristics of helium to achieve low-temperature refrigeration effects through a circulation system), mixed refrigeration cycle technology (using a variety of refrigerants (such as methane, ethane, nitrogen, etc.) to mix to form a suitable boiling point range, and gradually cool down through multi-stage heat exchange), Dewar cooling recovery technology (using the cooling energy generated during the evaporation of liquid hydrogen, and reducing the overall heat load through recovery and recycling), etc.

[0004] Passive insulation technologies mainly include multi-layer insulation technology (by setting multiple layers of low thermal conductivity materials between the outer wall of the storage tank and the environment to reduce the transfer of radiation and conduction heat), vacuum insulation technology (by forming a high vacuum environment between the inner and outer walls of the storage tank to eliminate gas conduction and convection heat loss) and the use of super insulation materials (using advanced materials (such as aerogel) to significantly reduce thermal conductivity).

[0005] In terms of liquid hydrogen storage, active refrigeration technology has low efficiency, high energy consumption and high cost. Therefore, existing technologies mostly use passive insulation technology to reduce heat leakage. According to the latest paper "Subambientdaytime radiative cooling of vertical surfaces" published in the journal Science, vertical radiative cooling can be achieved. If it is applied to the outer surface of a liquid hydrogen storage tank, it will reduce the heat leakage of the tank and reduce losses.

[0006] Therefore, technicians in this field are committed to providing a low-loss liquid hydrogen storage device that utilizes vertical radiation refrigeration and a multi-layer insulation structure, combining vertical radiation refrigeration technology with passive insulation technology to reduce heat leakage of liquid hydrogen storage tanks and replace existing active refrigeration technology. Summary of the invention

[0007] In view of the problem of heat leakage in the liquid hydrogen storage tank in the background technology, the present invention provides a liquid hydrogen storage tank device using vertical radiation refrigeration plus multi-layer insulation, and the technical scheme includes: a liquid hydrogen storage device, a spray foam insulation layer, a variable density multi-layer insulation layer, a steam cooling shield and a vertical radiation refrigeration layer, wherein the liquid hydrogen storage device, the spray foam insulation layer, the variable density multi-layer insulation layer and the vertical radiation refrigeration layer are arranged in sequence from the inside to the outside; the steam cooling shield is clamped in the middle of the variable density multi-layer insulation layer, and the steam cooling shield is connected to the liquid hydrogen storage device through a pipeline, and the steam cooling shield uses hydrogen generated by evaporation of liquid hydrogen in the liquid hydrogen storage device as a cooling medium;

[0008] The vertical radiation cooling layer includes: an inner substrate and an outer thin film coating.

[0009] The shape of the liquid hydrogen storage device is cylindrical with two semicircular heads; it is installed in a cool place.

[0010] The material of the spray foam insulation layer is polyurethane foam, and the thickness of the spray foam insulation layer is 3.56 cm.

[0011] The thickness of the variable density multi-layer insulation layer is 3.75 cm; the material of the variable density multi-layer insulation layer is a composite of a polyester film with double-sided aluminum plating and a partition layer;

[0012] The variable-density multi-layer insulation layer has a low-density layer on the side close to the liquid hydrogen storage device and a high-density layer on the side away from the liquid hydrogen storage device; it contains 45 layers in total.

[0013] The thickness of the vertical radiation cooling layer is 6.35 μm.

[0014] The substrate forms a sawtooth grating structure toward the thin film coating; the sawtooth protrusions include right-angled edges and oblique angled edges.

[0015] The ratio of the jagged right-angled side to the hypotenuse is 2:3.

[0016] The material of the substrate is polydimethylsiloxane.

[0017] The thin film coating comprises: a chromium adhesion layer, a first silver film, a silicon nitride spectrally selective thin film (54) and a second silver film arranged from the inside to the outside.

[0018] The chromium adhesion layer is a 10 nanometer chromium adhesion layer;

[0019] The first silver film is a 200 nanometer silver film;

[0020] The silicon nitride spectrally selective film is a 4-micron silicon nitride film;

[0021] The second silver film is a silver film directionally deposited on an inclined surface.

[0022] The beneficial effect of the present invention is that: a liquid hydrogen storage tank device with vertical radiation refrigeration plus multi-layer insulation is used to reduce heat leakage; that is, vertical radiation refrigeration is added on the basis of the original multi-layer insulation, and heat entry is reduced by vertical radiation refrigeration, thereby further reducing evaporation loss (heat loss) in the storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an embodiment of a liquid hydrogen storage tank device utilizing vertical radiation refrigeration and multi-layer insulation of the present invention.

[0024] Figure 2 It is a partial cross-sectional view of an embodiment of the present invention.

[0025] Figure 3 Schematic diagram of the structure of the vertical radiation cooling layer in an embodiment of the present invention.

[0026] Figure 4 Adiabatic temperature local distribution diagram modeled for an embodiment of the present invention.

[0027] Among them, 1-hydrogen storage device, 2-spray foam insulation layer, 3-variable density multilayer insulation layer 3, 4-steam cooling shield, 5-vertical radiation cooling layer, 51-substrate, 52-chromium adhesion layer, 53-first layer of silver film, 54-silicon nitride spectrally selective film, 55-second layer of silver film. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0029] like Figure 1 to Figure 3 The embodiment of the present invention shown includes: a liquid hydrogen storage device 1, a spray foam insulation layer 2, a variable density multi-layer insulation layer 3 and a vertical radiation cooling layer 5 arranged in sequence from the inside to the outside, wherein a steam cooling shield 4 is sandwiched between the variable density multi-layer insulation layer 3, and each external insulation protection layer (spray foam insulation layer 2, variable density multi-layer insulation layer 3, steam cooling shield 4 and vertical radiation cooling layer 5) is used for insulation protection, and each external insulation protection layer is sequentially attached to the outside of the liquid hydrogen storage device 1 to provide insulation protection for the storage tank. The outermost vertical radiation cooling layer provides radiation cooling for the storage tank; wherein:

[0030] The liquid hydrogen storage device 1 is used for filling and storing liquid hydrogen and is provided with a solid shell;

[0031] The spray foam insulation layer 2 is wrapped around the outside of the liquid hydrogen storage device 1 to provide preliminary insulation protection and reduce the transfer of external heat to the inside;

[0032] The variable density multi-layer insulation layer 3 is wrapped in the spray foam insulation layer to further reduce heat transfer, and insulation is mainly achieved by reducing solid heat conduction, radiation heat transfer and gas heat conduction. Specifically, the variable density multi-layer insulation layer 3 is attached to the outside of the spray foam insulation layer 2, with a low-density layer on the inside and a high-density layer on the outside. It is composed of a double-sided aluminum-plated polyester film and a partition layer. The spacing material is arranged between the polyester films to form a multi-layer structure. A steam cooling shield 4 is arranged inside the variable density multi-layer insulation layer 3. The steam cooling shield 4 uses hydrogen generated by the evaporation of liquid hydrogen as a cooling medium, which circulates in the shielding layer through a specific pipeline, thereby

[0033] The steam cooling shield 4 is coupled inside the variable density multi-layer insulation layer 3, and utilizes the steam generated by the volatilization of liquid hydrogen in the liquid hydrogen storage device 1 to cool the shield layer, thereby reducing the heat leakage into the storage tank;

[0034] The vertical radiation cooling layer 5 is located at the outermost side of the storage tank. Its main function is to significantly reduce the degree of radiant heat transferred from the external environment to the interior of the storage tank by reflecting thermal radiation.

[0035] In this embodiment, the shape of the liquid hydrogen storage device 1 is a cylinder with two semicircular heads. Compared with the spherical structure, the cylindrical shape can withstand uniformly distributed internal pressure inside the storage tank, and the stress concentration phenomenon is less. The head design (usually elliptical or hemispherical) can effectively reduce the stress concentration at the end of the tank wall. Therefore, the storage tank 1 of this embodiment adopts a cylindrical design with two heads.

[0036] In this embodiment, the material of the spray foam insulation layer 2 is polyurethane foam, and the thickness of the spray foam insulation layer 2 along the radial direction of the storage tank is 3.56 cm; the spray foam insulation layer 2 is evenly attached to the outer wall of the liquid hydrogen storage device 1, and is made of polyurethane foam. The thermal conductivity is generally in the range of 0.02-0.03W / m·K, which is very excellent in insulation materials. It can effectively reduce the heat entering the liquid hydrogen storage tank through heat conduction, thereby reducing the evaporation rate of liquid hydrogen. At the same time, it has high compressive strength and impact resistance. In a low temperature environment, its closed-cell structure is more stable and is not easily deformed or cracked due to temperature differences. Its stable physical properties can withstand the expansion and contraction of the surface of the storage tank.

[0037] In this embodiment, the variable density multilayer insulation layer 3 has a low density layer on the side close to the liquid hydrogen storage device 1 and a high density layer on the side away from the liquid hydrogen storage device 1; the variable density multilayer insulation layer 3 has a thickness of 3.75 cm and is made of a polyester film with double-sided aluminum plating and a partition layer. It contains 45 layers in total.

[0038] In this embodiment, the steam cooling shield is mainly made of copper or aluminum, including pipes (for steam flow) and shielding layers (for heat exchange).

[0039] In this embodiment, the thickness of the vertical radiation cooling layer 5 is 6.35 μm.

[0040] like Figure 3 The vertical radiation cooling layer 5 shown includes: an inner substrate and an outer thin film coating, which has a high emissivity and a low solar absorptivity. The surface of the object transfers heat to the atmosphere through radiation, reducing the heat transferred from the atmosphere to the interior by 5%-8% (such as Figure 4 shown); where:

[0041] The substrate 51 is formed by mold forming to form a serrated grating structure facing outward (toward the direction of the thin film coating); the serrated protrusion includes a right-angled side and a beveled side, and the angle between the beveled side and the right-angled side is about 33° (the angle is determined by the aspect ratio of 2:3); the material of the substrate is polydimethylsiloxane (PDMS), which is easy to form and has excellent thermosetting properties.

[0042] The thin film coating includes: a chromium adhesion layer 52, a first silver film 53, a silicon nitride spectrally selective film 54 and a second silver film 55 arranged from the inside to the outside, wherein the chromium adhesion layer 52 is a 10-nanometer chromium (Cr) adhesion layer; the first silver film 53 is a 200-nanometer silver (Ag) film, which provides high reflectivity; the silicon nitride spectrally selective film 54 is a 4-micron silicon nitride (SiN) film, which provides spectral selectivity; the second silver film 55 is a silver (Ag) film directionally deposited on an inclined surface, which is used to optimize directional radiation.

[0043] The working principle of the present invention is:

[0044] At the storage location of the liquid hydrogen storage tank, the external heat is first reflected back to the atmosphere through the vertical radiation cooling layer 5, reducing the heat entering the interior and reducing the heat loss of the tank;

[0045] The heat then passes through the tank wall into the variable density multilayer insulation layer 3, where it is first absorbed by the steam cooling shield and transferred to the hydrogen cooling flow. The steam hydrogen flows in the shield while absorbing the heat introduced from the outside, which greatly reduces the heat flowing into the tank. By controlling the flow rate and circulation volume of the cooling steam, the temperature gradient of the shield is optimized, thereby maintaining the overall insulation effect.

[0046] Finally, the liquid hydrogen storage device 1 is isolated from the heat outside by spraying the foam insulation layer 2 .

[0047] In this embodiment, the liquid hydrogen storage tank is installed on the ground in a well-ventilated place; in order to reduce heat loss, it is placed in a shaded place.

Claims

1. A liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation, characterized in that: include: A liquid hydrogen storage device (1), a spray foam insulation layer (2), a variable density multi-layer insulation layer (3), a steam cooling shield (4) and a vertical radiation refrigeration layer (5), wherein the liquid hydrogen storage device (1), the spray foam insulation layer (2), the variable density multi-layer insulation layer (3) and the vertical radiation refrigeration layer (5) are arranged in sequence from the inside to the outside; the steam cooling shield (4) is sandwiched between the variable density multi-layer insulation layer (3), the steam cooling shield (4) is connected to the liquid hydrogen storage device (1) through a pipeline, and the steam cooling shield (4) uses hydrogen generated by evaporation of liquid hydrogen in the liquid hydrogen storage device (1) as a cooling medium; The vertical radiation cooling layer (5) comprises: an inner substrate (51) and an outer thin film coating.

2. According to claim 1, a liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation is characterized in that: The liquid hydrogen storage device (1) is in the shape of a cylinder with two semicircular heads; it is installed in a cool place.

3. According to claim 1, a liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation is characterized in that: The material of the spray foam insulation layer (2) is polyurethane foam, and the thickness of the spray foam insulation layer (2) is 3.56 cm.

4. The liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation according to claim 1 is characterized in that: The thickness of the variable-density multilayer heat-insulating layer (3) is 3.75 cm; the material of the variable-density multilayer heat-insulating layer (3) is a composite of a polyester film with double-sided aluminum plating and a partition layer; The variable-density multi-layer insulation layer (3) has a low-density layer on the side close to the liquid hydrogen storage device (1), and a high-density layer on the side away from the liquid hydrogen storage device (1); it comprises 45 layers in total.

5. According to claim 1, a liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation is characterized in that: The thickness of the vertical radiation cooling layer (5) is 6.35 μm.

6. The liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation according to claim 1 is characterized in that: The substrate (51) forms a sawtooth grating structure facing the thin film coating; the sawtooth protrusions include right-angled edges and oblique angled edges.

7. A liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation according to claim 6, characterized in that: The ratio of the jagged right-angled side to the hypotenuse is 2:

3.

8. A liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation according to claim 6 or 7, characterized in that: The material of the substrate is polydimethylsiloxane.

9. The liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation according to claim 1 is characterized in that: The thin film coating comprises: a chromium adhesion layer (52), a first silver film (53), a silicon nitride spectrally selective thin film (54) and a second silver film (55) arranged from the inside to the outside.

10. A liquid hydrogen storage tank device using vertical radiation refrigeration and multi-layer insulation according to claim 9, characterized in that: The chromium adhesion layer (52) is a 10 nanometer chromium adhesion layer; The first silver film (53) is a 200 nanometer silver film; The silicon nitride spectrally selective film (54) is a 4 micron silicon nitride film; The second silver film (55) is a silver thin film directionally deposited on an inclined surface.

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