A new design method for cryogenic liquid hydrogen storage tank

Abstract

The present invention relates to a design method for a novel cryogenic liquid hydrogen storage tank, and belongs to the field of liquid hydrogen storage technology. The design method for the novel cryogenic liquid hydrogen storage tank includes: completing the strength design of the storage tank, including calculating the thickness of the wall panels, top panels, and bottom panels of the inner tank and the outer tank; completing the cold insulation design of the storage tank, including calculating the heat transfer of the top panel, wall panels, and bottom panel of the storage tank to calculate the evaporation rate of the storage tank, and adjusting the relevant parameters of the liquid nitrogen cold screen according to the requirements for the evaporation rate of the storage tank. The present invention is aimed at a large-scale vertical cryogenic liquid hydrogen storage tank that adopts a liquid nitrogen cold screen structure and a dome design for the first time, and innovatively completes the strength design and cold insulation design of the storage tank.

Description

Technical Field

[0001] The invention relates to a design method for a novel low-temperature liquid hydrogen storage tank, belonging to the technical field of liquid hydrogen storage. Background Art

[0002] Liquid hydrogen is a colorless, odorless, high-energy, low-temperature energy source, a liquid form of hydrogen. Because liquid hydrogen is 800 times denser than hydrogen gas, its high storage density, high efficiency, and suitability for long-distance transport make it a superior storage and transportation method for hydrogen compared to other transportation methods.

[0003] The liquefaction of hydrogen is achieved through multiple cycles of adiabatic expansion. The boiling point (20.37K, -252.78℃) and freezing point (13.96K, -259.19℃) at normal pressure are very low, and its liquefied storage is difficult. And because the boiling point of liquid hydrogen is very low and the latent heat of vaporization is small (0.45kJ / g), a little heat seeping into the container from the outside can cause rapid boiling and loss of liquid hydrogen. Therefore, the thermal insulation performance of the liquid hydrogen storage tank directly affects the evaporation rate of liquid hydrogen. For a long time, the core difficulty of storing liquid hydrogen at normal pressure is the insulation problem of liquid hydrogen during storage. In addition, for a long time, the storage of liquid hydrogen worldwide has been limited to high-pressure storage, and large-scale liquid hydrogen storage is impossible. Therefore, it is extremely necessary to invent and design a new type of low-temperature liquid hydrogen storage tank. Summary of the Invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a new design method for low-temperature liquid hydrogen storage tanks, so that the corresponding storage tanks can be structurally large-scale liquid hydrogen storage tanks, with a volume of 100,000 cubic meters or more.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A design method for a novel cryogenic liquid hydrogen storage tank, the novel cryogenic liquid hydrogen storage tank being a vertical atmospheric pressure cryogenic storage tank, comprising an outer tank and an inner tank, the outer tank and the inner tank being cylindrical or cylindrical with a regular polygonal cross-section, and respectively comprising a wall panel, a bottom panel, and a dome-shaped top panel; a liquid nitrogen cold shield and an insulating material are respectively provided between the outer tank and the inner tank, wherein the liquid nitrogen cold shield is laid along the outer wall of the inner tank; the design method for the novel cryogenic liquid hydrogen storage tank comprises:

[0007] Complete the strength design of the storage tank, including calculating the thickness of the inner and outer tank wall, roof and floor plates;

[0008] Complete the cold insulation design of the storage tank, including calculating the heat transfer of the tank top plate, wall plate and bottom plate to calculate the tank evaporation rate, and adjust the relevant parameters of the liquid nitrogen cold screen according to the requirements of the tank evaporation rate.

[0009] Furthermore, the calculation method of the inner tank wall thickness is as follows:

[0010] e=max{e s，c , e s，t , e min}

[0011]

[0012]

[0013] Among them, e is the thickness of the inner tank wall, e s，t Calculate the thickness of the inner tank wall under the hydrostatic test condition, e s，c Calculate the thickness of the inner tank wall under operating conditions, e min is the minimum design thickness of the inner tank wall, ρ c is the maximum density of the storage medium under operating conditions, ρ t is the maximum density of the test medium under the water pressure test condition, P c is the inner tank design pressure, P t is the internal pressure of the inner tank minus the top plate gravity, σ sc is the allowable stress of the inner tank wall under operating conditions, σ st is the allowable stress of the inner tank wall under the hydrostatic test condition, H is the highest design liquid level of liquid hydrogen, and D i is the inner diameter of the inner tank.

[0014] Furthermore, the calculation method of the outer tank wall thickness is as follows:

[0015]

[0016] e os is the outer tank wall thickness, P i is the sum of the internal pressure, internal air pressure and insulation system pressure, D0 is the inner diameter of the outer tank, c is the corrosion allowance, and σ0 is the allowable stress of the outer tank wall.

[0017] Furthermore, the inner tank bottom plate and the outer tank bottom plate each include an annular edge plate and a middle plate, the annular edge plate being arranged along the outer circle of the inner tank bottom plate or the outer tank bottom plate and being formed by overlapping a plurality of edge plate units, and the middle plate being arranged inside the annular edge plate and being formed by overlapping a plurality of middle plate units;

[0018] The calculation method of the inner tank bottom plate thickness is as follows:

[0019] Inner tank annular edge plate thickness: e a，1 =max{(3.0+e s，1 / 3), 8}

[0020] Minimum width of inner tank annular edge plate:

[0021] e a，1 is the thickness of the inner tank annular edge plate, e s，1 is the thickness of the bottom ring of the inner tank wall, l a，1 is the minimum width of the inner tank annular edge plate, and H is the maximum design level of liquid hydrogen;

[0022] The calculation method for the outer tank bottom plate thickness is as follows:

[0023] Thickness of outer tank annular edge plate: e a，2 =max{(3.0+e s，2 / 3), 8}

[0024] Minimum width of outer tank annular edge plate:

[0025] e a，2 is the thickness of the outer tank annular edge plate, e s，2 is the thickness of the bottom ring of the outer tank wall, l a，2 is the minimum width of the outer tank annular edge plate, and H is the maximum design liquid level of liquid hydrogen.

[0026] Furthermore, the calculation method for the thickness of the inner tank and outer tank top plate is:

[0027] e r =max{e r1 , e r2}

[0028] Spherical top:

[0029] Buckling calculation:

[0030] e r is the top plate thickness, e r1 is the top plate thickness of the spherical roof, e r2 Top plate thickness for buckling calculation, P r is the internal pressure minus the top plate gravity, R r is the curvature radius of the top plate, P e is the external load, E is the elastic modulus, σ1 is the allowable stress of the top plate, and η1 is the welding joint coefficient of the weld.

[0031] Furthermore, the calculation method of the daily evaporation rate of the storage tank is:

[0032]

[0033] Among them, BOR is the daily evaporation rate, γ is the latent heat of vaporization of liquid hydrogen, V is the volume corresponding to the maximum design liquid level of the storage tank, ρ0 is the density of liquid hydrogen, Φ s is the total heat transfer of the tank.

[0034] Furthermore, the total heat transfer of the tank Φ s for:

[0035] Φ s =Φ1+Φ2+Φ3

[0036] Among them, Φ1 is the heat transfer of the inner tank top plate, Φ2 is the heat transfer of the inner tank wall plate, and Φ3 is the heat transfer of the inner tank bottom plate;

[0037] The calculation method for the heat transfer of the inner tank top plate is:

[0038] Among them, Φ1 is the heat transfer of the inner tank top plate, A1 is the outer surface area of ​​the inner tank top plate, T1 is the outer surface temperature of the inner tank top plate, T2 is the inner surface temperature of the inner tank top plate, δ2 is the thickness of the inner tank top plate, and λ1 is the thermal conductivity coefficient of the inner tank top plate;

[0039] The calculation method for the heat transfer of the inner tank wall is:

[0040] Φ2 is the heat transfer of the inner tank wall, T4 is the equivalent temperature of the liquid nitrogen cold screen on the tank wall, T3 is the liquid hydrogen storage temperature, L is the height of the inner tank wall, h1 is the surface heat transfer coefficient of the inner tank wall, λ 3i is the thermal conductivity of each layer of insulation material on the tank wall, d1 is the diameter of the inner tank, d i The corresponding diameter of each layer of insulation material on the tank wall;

[0041] The heat transfer calculation method of the inner tank bottom plate is:

[0042] Φ3 is the heat transfer of the inner tank bottom plate, T5 is the equivalent temperature of the liquid nitrogen cold screen at the bottom of the tank, T3 is the liquid hydrogen storage temperature, A4 is the surface area of ​​the bottom plate, λ 4i is the thermal conductivity of the insulation material of the bottom plate and each layer of the tank bottom, δ 4i It is the thickness of the tank bottom and each layer of insulation material.

[0043] Furthermore, the calculation method of the equivalent temperature T4 of the tank wall liquid nitrogen cold screen is:

[0044] kA b T4=q m c p (t′1-t″1)

[0045]

[0046]

[0047] Wherein, k is the comprehensive heat transfer coefficient; A b is the equivalent heat transfer area of ​​the liquid nitrogen cooling screen on the tank wall; g m is the mass flow rate; c pis the specific heat capacity of liquid nitrogen; t′ is the liquid nitrogen outlet temperature; t″1 is the liquid nitrogen inlet temperature; h is the convective heat transfer coefficient; δ s Liquid nitrogen tube wall thickness; λ s is the thermal conductivity of the liquid nitrogen cooling screen; l is the thermal conductivity of liquid nitrogen; ρ is the density of liquid nitrogen; u is the flow rate of liquid nitrogen; d is the diameter of the liquid nitrogen cooling screen tube; η is the dynamic viscosity of liquid nitrogen.

[0048] Furthermore, the calculation method of the equivalent temperature T5 of the liquid nitrogen cooling screen at the bottom of the tank is:

[0049] kA d T5=q m c p (t′1-t″1)

[0050]

[0051]

[0052] Wherein, k is the comprehensive heat transfer coefficient; A d is the equivalent heat transfer area of ​​the liquid nitrogen cooling screen on the tank bottom; q m is the mass flow rate; c p is the specific heat capacity of liquid nitrogen; t′ is the liquid nitrogen outlet temperature; t″1 is the liquid nitrogen inlet temperature; h is the convective heat transfer coefficient; δ s Liquid nitrogen tube wall thickness; λ s is the thermal conductivity of the liquid nitrogen cooling screen; l is the thermal conductivity of liquid nitrogen; ρ is the density of liquid nitrogen; u is the flow rate of liquid nitrogen; d is the diameter of the liquid nitrogen cooling screen tube; η is the dynamic viscosity of liquid nitrogen.

[0053] Furthermore, according to the requirements for the evaporation rate of the storage tank, the relevant parameters of the liquid nitrogen cold shield are adjusted, including the liquid nitrogen flow rate, the diameter of the liquid nitrogen cold shield tube, the specific heat capacity of liquid nitrogen, the thermal conductivity of liquid nitrogen, the density of liquid nitrogen and the dynamic viscosity of liquid nitrogen, to complete the cold preservation design of the storage tank.

[0054] The beneficial effects of the present invention are:

[0055] This invention, targeting the first large-scale vertical cryogenic liquid hydrogen storage tanks that utilize a liquid nitrogen cooling shield structure and a dome design, innovatively achieves both tank strength and cold-insulation design. By adjusting the liquid nitrogen cooling shield structure and related parameters (tube diameter, flow rate, etc.), large-scale vertical liquid hydrogen storage tanks can be designed to meet the requirements of different regions and different evaporation rates. The implementation of this design method enables liquid hydrogen storage tanks to have capacities of 10,000 cubic meters or even larger, further promoting the development of domestic hydrogen energy storage technology and laying the foundation for the storage, transportation, and application of hydrogen energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1-1 It is an existing double-layer vacuum insulated liquid hydrogen spherical tank;

[0057] Figure 1-2 It is an existing double-layer high vacuum insulated cylindrical liquid hydrogen storage tank;

[0058] Figure 2 This is a schematic structural diagram of the novel cryogenic liquid hydrogen storage tank of the present invention;

[0059] Among them, 1-outer tank, 2-annular gap cold insulation layer, 3-liquid nitrogen cold shield, 7-bottom cold insulation layer, 8-inner tank;

[0060] Figure 3 It is a schematic diagram of the structure of the inner tank bottom plate or the outer tank bottom plate;

[0061] Among them, 5-annular edge plate, 6-middle plate. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0063] Existing liquid hydrogen storage tanks, most of the foreign liquid hydrogen tanks adopt double-layer vacuum insulation spherical tanks, such as Figure 1-1 As shown; Domestically, double-layer high vacuum insulation cylindrical storage tanks are basically used, such as Figure 1-2 As shown, both domestic and foreign liquid hydrogen storage tanks use vacuum pressure storage. The capacity of double-layer vacuum spherical tanks and double-layer high vacuum insulated cylindrical storage tanks is limited. Currently, the largest double-layer vacuum insulated spherical tank is 4,000 cubic meters, and the capacity of double-layer high vacuum insulated cylindrical storage tanks is 1,250 cubic meters. Within the scope of pressure vessels, due to limitations on steel plate materials and manufacturing restrictions, the wall thickness of the storage tank cannot be too thick, so the diameter of the storage tank cannot be large. And for safety reasons, the volume requirements for pressurized containers storing explosive gases are becoming increasingly stringent. From the structural analysis of double-layer high vacuum spherical tanks and double-layer high vacuum insulated cylindrical storage tanks, it is difficult to exceed 100 million, and liquid hydrogen storage tanks in the form of pressurized storage are not suitable for the large-scale development trend of liquid hydrogen storage tanks. In addition, the manufacturing and operation requirements of double-layer vacuum insulated spherical tanks and double-layer high vacuum insulated cylindrical storage tanks are relatively high. Currently, double-layer vacuum spherical tanks and double-layer high vacuum insulated cylindrical storage tanks all use vacuum insulation. Vacuum insulation has strict requirements on vacuum pumps during manufacturing. At the same time, when the storage tank is in operation, the vacuum degree of the storage tank needs to be periodically checked to ensure the insulation effect. In addition, double-layer vacuum spherical tanks and double-layer high vacuum insulated cylindrical storage tanks use double-layer steel structures. From the perspective of the safety and evaporation loss of liquid hydrogen storage tanks, there are certain safety risks and large evaporation losses.

[0064] The present invention provides a novel cryogenic liquid hydrogen storage tank and a design method for the storage tank. The novel cryogenic liquid hydrogen storage tank is a vertical atmospheric pressure cryogenic storage tank comprising an outer tank and an inner tank, wherein a liquid nitrogen cold shield and an insulating material are respectively provided between the outer tank and the inner tank.

[0065] An optional implementation method, such as Figure 2 As shown, an annular insulation space is formed between the outer tank 1 and the inner tank 8. The annular insulation space includes an annular gap cold insulation layer 2 and a bottom cold insulation layer 7. The annular gap cold insulation layer 2 is located on the top and outside of the side wall of the inner tank 8, and the bottom cold insulation layer 7 is located at the bottom of the inner tank 8. In the annular gap cold insulation layer 2, a liquid nitrogen cold shield 3 and a first insulation material are sequentially provided from the inside to the outside, and in the bottom cold insulation layer 7, a liquid nitrogen cold shield 3 and a second insulation material are sequentially provided from the inside to the outside; wherein, the liquid nitrogen cold shield 3 is composed of a cold shield pipe filled with liquid nitrogen, which is laid on the outer wall of the inner tank 8. The liquid nitrogen cold shield 3 maintains the low temperature environment of the inner tank 8 by circulating liquid nitrogen. The first insulation material is filled in the annular gap cold insulation layer 2, and the second insulation material is filled in the bottom cold insulation layer 7.

[0066] The first thermal insulation material is used to enhance thermal insulation, reduce heat leakage, and lower the daily evaporation rate of the storage tank. In an optional embodiment, the first thermal insulation material is perlite or glass beads, wherein the perlite can be expanded perlite.

[0067] The second insulating material is used to reduce heat transfer between the load-bearing base and the tank wall, effectively reducing heat leakage from the bottom. This second insulating material works together with the liquid nitrogen cold shield to maintain the coolness and thermal insulation of the tank bottom. In one optional embodiment, the second insulating material is foam glass brick.

[0068] The outer tank and inner tank are cylindrical or have a regular polygonal cross-section, and each includes a wall panel, a bottom panel, and a dome-shaped roof panel. The dome design of the tank allows the tank to withstand the pressure of the cold insulation material on its top through its self-supporting ability.

[0069] An optional embodiment, in which the liquid nitrogen cold shield tubes on the dome and bottom plate of the inner tank 8 are both S-shaped, and the liquid nitrogen cold shield tubes on the side wall of the inner tank 8 are spiral-shaped, surrounding the side wall of the inner tank by spiral winding. By adjusting the diameter, spacing and liquid nitrogen flow of the cold shield tubes on the top plate, bottom plate and wall plate of the inner tank 8, external energy input continuously supplies liquid nitrogen, and the heat that may be introduced from the outside is evacuated to ensure the low temperature environment of the inner tank. The settings of the S-shaped cold shield tube and the spiral cold shield tube facilitate the setting of the liquid nitrogen inlet and outlet. The liquid nitrogen cold shields 3 on the dome, bottom plate and side wall of the inner tank 8 operate in parallel to reduce the vaporization of liquid nitrogen and reduce flow resistance, thereby ultimately reducing operating costs.

[0070] The design method of the novel cryogenic liquid hydrogen storage tank includes:

[0071] Complete the strength design of the storage tank, including calculating the thickness of the inner and outer tank wall, roof and floor plates;

[0072] Complete the cold insulation design of the storage tank, including calculating the heat transfer of the tank top plate, wall plate and bottom plate to calculate the tank evaporation rate, and adjust the relevant parameters of the liquid nitrogen cold screen according to the requirements of the tank evaporation rate.

[0073] In an optional embodiment, the inner tank wall thickness is calculated as follows:

[0074] e=max{e s，c , e s，t , e min}

[0075]

[0076]

[0077] Where, e is the thickness of the inner tank wall, mm; e s，t is the calculated thickness of the inner tank wall under the hydrostatic test condition, mm; e s，c is the calculated thickness of the inner tank wall under operating conditions, mm; e min is the minimum design thickness of the inner tank wall, mm; ρ c is the maximum density of the storage medium under operating conditions, kg / m 3 ρ t is the maximum density of the test medium under the water pressure test condition, kg / m 3 ;P c is the design pressure of the inner tank, kPa, where for the inner tank with top opening, the design pressure is taken as 0; P t is the internal pressure of the inner tank minus the weight of the top plate, kPa; σ sc is the allowable stress of the inner tank wall under operating conditions, MPa; σ st is the allowable stress of the inner tank wall under the water pressure test condition, MPa; H is the maximum design liquid level of liquid hydrogen, m; D i is the inner diameter of the inner tank, m.

[0078] e min The values ​​are as follows: When D i ≤10m,e min Take 5mm; when 10<D i When ≤30m, e min Take 6mm; when 30<D i When ≤60m, e min Take 8mm; when D i >60m, e min Take 10mm.

[0079] The bottom ring of the inner tank wall is the pressure-bearing area, and its thickness is not less than the thickness of the upper wall of the inner tank.

[0080] In an optional embodiment, the outer tank wall thickness is calculated as follows:

[0081]

[0082] e os is the outer tank wall thickness, mm; P i is the sum of the internal pressure, internal air pressure and insulation system pressure, in kPa, where the internal pressure refers to the hydrostatic pressure during leakage, the internal air pressure refers to the pressure generated by gas evaporation, and the insulation system pressure refers to the pressure generated by the insulation material on the outer tank wall; D0 is the inner diameter of the outer tank, in m; c is the corrosion allowance, in mm; σ0 is the allowable stress of the outer tank wall, in MPa.

[0083] In an optional embodiment, the inner tank bottom plate and the outer tank bottom plate each include an annular edge plate and a middle plate, wherein the annular edge plate is arranged along the outer circumference of the inner tank bottom plate or the outer tank bottom plate and is formed by overlapping a plurality of edge plate units, and the middle plate is arranged inside the annular edge plate and is formed by overlapping a plurality of middle plate units;

[0084] The calculation method of the inner tank bottom plate thickness is as follows:

[0085] Inner tank annular edge plate thickness: e a，1 =max{(3.0+e s，1 / 3), 8}

[0086] Minimum width of inner tank annular edge plate:

[0087] e a，1 is the thickness of the inner tank annular edge plate, mm; e s，1 is the thickness of the bottom ring of the inner tank wall, mm; l a，1 is the minimum width of the inner tank annular edge plate, mm; H is the maximum design liquid level of liquid hydrogen, m;

[0088] The calculation method for the outer tank bottom plate thickness is as follows:

[0089] Thickness of outer tank annular edge plate: e a，2 =max{(3.0+e s，2 / 3), 8}

[0090] Minimum width of outer tank annular edge plate:

[0091] e a，2 is the thickness of the outer tank annular edge plate, mm; e s，2 is the thickness of the bottom ring of the outer tank wall, mm; l a，2is the minimum width of the outer tank annular edge plate, mm; H is the maximum design liquid level of liquid hydrogen, m.

[0092] The thickness of the center plate of the inner and outer tank bottom plates shall be no less than 5 mm (excluding corrosion allowance), and the minimum width of the overlapped joint of the center plate unit shall be at least five times the thickness of the center plate. The minimum overlap width of the center plate unit overlapped on the edge plate shall be 60 mm. The edge plate units shall be butt-jointed. The distance between the welded joints of any three adjacent center plate units in the bottom plate, as well as the distance between the welded joint of the center plate unit and the butt joint of the edge plate, shall be no less than 300 mm.

[0093] In an optional embodiment, the calculation method for the thickness of the inner tank and the outer tank top plate is:

[0094] e r =max{e r1 , e r2}

[0095] Spherical top:

[0096] Buckling calculation:

[0097] e r is the top plate thickness, mm; e r1 is the thickness of the spherical top plate, mm; e r2 Top plate thickness for buckling calculation, mm; P r is the internal pressure minus the top plate gravity, kPa; R r is the curvature radius of the top plate, m; P e is the external load, kPa; E is the elastic modulus, MPa; σ1 is the allowable stress of the top plate, MPa; η1 is the welding joint coefficient of the weld.

[0098] In an optional embodiment, the calculation method of the daily evaporation rate of the storage tank is:

[0099]

[0100] Wherein, BOR is the daily evaporation rate; γ is the latent heat of vaporization of liquid hydrogen, J / kg; V is the volume corresponding to the maximum design liquid level of the storage tank, m 3 ; ρ0 is the density of liquid hydrogen, kg / m 3 Φ s is the total heat transfer of the tank.

[0101] In an optional embodiment, the total heat transfer capacity of the storage tank is Φ s for:

[0102] Φ s =Φ1+Φ2+Φ3

[0103] Among them, Φ1 is the heat transfer of the inner tank top plate, Φ2 is the heat transfer of the inner tank wall plate, and Φ3 is the heat transfer of the inner tank bottom plate;

[0104] The calculation method for the heat transfer of the inner tank top plate is:

[0105] Among them, Φ1 is the heat transfer of the inner tank top plate, A1 is the outer surface area of ​​the inner tank top plate, m 2 ; T1 is the outer surface temperature of the inner tank top plate, K; T2 is the inner surface temperature of the inner tank top plate, K; δ2 is the thickness of the inner tank top plate, m; λ1 is the thermal conductivity of the inner tank top plate, W / (m·K);

[0106] The calculation method for the heat transfer of the inner tank wall is:

[0107] Φ2 is the heat transfer capacity of the inner tank wall, T4 is the equivalent temperature of the liquid nitrogen cold screen on the tank wall, K; T3 is the liquid hydrogen storage temperature, K; L is the height of the inner tank wall, m; h1 is the surface heat transfer coefficient of the inner tank wall, W / (m 2 K); λ 3i is the thermal conductivity of each layer of insulation material of the tank wall, W / (m·K); d1 is the diameter of the inner tank, m; d i is the corresponding diameter of each layer of insulation material on the tank wall, m.

[0108] The heat transfer calculation method of the inner tank bottom plate is:

[0109] Φ3 is the heat transfer capacity of the inner tank bottom plate, T5 is the equivalent temperature of the liquid nitrogen cold screen at the bottom of the tank, K; T3 is the liquid hydrogen storage temperature, K; A4 is the surface area of ​​the bottom plate, m 2 ;λ 4i is the thermal conductivity of the insulation material of the bottom plate and each layer of the tank bottom, W / (m·K); δ 4i is the thickness of the tank bottom and each layer of insulation material, m.

[0110] In an optional embodiment, the calculation method of the equivalent temperature T4 of the tank wall liquid nitrogen cold shield is:

[0111] kA b T4=q m c p (t′1-t″1)

[0112]

[0113]

[0114] Where k is the comprehensive heat transfer coefficient, W / (m 2 K); A b is the equivalent heat transfer area of ​​the liquid nitrogen cooling screen on the tank wall, m 2 ;qm is the mass flow rate, kg / s; c p is the specific heat capacity of liquid nitrogen, J / (kg·K); t′ is the liquid nitrogen outlet temperature, K; t″1 is the liquid nitrogen inlet temperature, K; h is the convective heat transfer coefficient, W / (m 2 ·K); δ s Liquid nitrogen tube wall thickness, m; λ s is the thermal conductivity of the liquid nitrogen cooling shield, W / (m·K); λ l is the thermal conductivity of liquid nitrogen, W / (m·K); ρ is the density of liquid nitrogen, kg / m 3 ; u is the liquid nitrogen flow rate, m / s; d is the diameter of the liquid nitrogen cooling tube, m; η is the dynamic viscosity of liquid nitrogen, Pa·s.

[0115] In an optional embodiment, the calculation method of the equivalent temperature T5 of the liquid nitrogen cooling screen at the bottom of the tank is:

[0116] kA d T5=q m c p (t′1-t″1)

[0117]

[0118]

[0119] Where k is the comprehensive heat transfer coefficient, W / (m 2 K); A d is the equivalent heat transfer area of ​​the liquid nitrogen cooling screen on the tank bottom, m 2 ;q m is the mass flow rate, kg / s; c p is the specific heat capacity of liquid nitrogen, J / (kg·K); t′ is the liquid nitrogen outlet temperature, K; t″1 is the liquid nitrogen inlet temperature, K; h is the convective heat transfer coefficient, W / (m 2 .K);δ s Liquid nitrogen tube wall thickness, m; λ s is the thermal conductivity of the liquid nitrogen cooling shield, W / (m·K); λ l is the thermal conductivity of liquid nitrogen, W / (m·K); ρ is the density of liquid nitrogen, kg / m 3 ; u is the liquid nitrogen flow rate, m / s; d is the diameter of the liquid nitrogen cooling tube, m; η is the dynamic viscosity of liquid nitrogen, Pa·s.

[0120] An optional implementation method is to adjust the relevant parameters of the liquid nitrogen cold shield according to the requirements for the evaporation rate of the storage tank, including the liquid nitrogen flow rate, the diameter of the liquid nitrogen cold shield tube, the specific heat capacity of liquid nitrogen, the thermal conductivity of liquid nitrogen, the density of liquid nitrogen and the dynamic viscosity of liquid nitrogen, thereby completing the cold preservation design of the storage tank.

[0121] This invention, targeting the first large-scale vertical cryogenic liquid hydrogen storage tanks that utilize a liquid nitrogen cooling shield structure and a dome design, innovatively achieves both tank strength and cold-insulation design. By adjusting the liquid nitrogen cooling shield structure and related parameters (tube diameter, flow rate, etc.), large-scale vertical liquid hydrogen storage tanks can be designed to meet the requirements of different regions and different evaporation rates. The implementation of this design method enables liquid hydrogen storage tanks to have capacities of 10,000 cubic meters or even larger, further promoting the development of domestic hydrogen energy storage technology and laying the foundation for the storage, transportation, and application of hydrogen energy.

[0122] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A design method for a new type of cryogenic liquid hydrogen storage tank, characterized in that: The novel cryogenic liquid hydrogen storage tank is a vertical atmospheric pressure cryogenic storage tank comprising an outer tank and an inner tank. The outer tank and the inner tank are cylindrical or cylindrical with a regular polygonal cross section, and each comprises a wall plate, a bottom plate, and a dome-shaped top plate. A liquid nitrogen cold shield and an insulating material are respectively provided between the outer tank and the inner tank, wherein the liquid nitrogen cold shield is laid along the outer wall of the inner tank. The design method of the novel cryogenic liquid hydrogen storage tank includes: Complete the strength design of the storage tank, including calculating the thickness of the inner and outer tank wall, roof and floor plates; Complete the cold insulation design of the storage tank, including calculating the evaporation rate of the storage tank by calculating the heat transfer of the storage tank top plate, wall plate and bottom plate, and adjusting the relevant parameters of the liquid nitrogen cold shield according to the requirements of the storage tank evaporation rate. The relevant parameters of the liquid nitrogen cold shield include: liquid nitrogen flow rate, liquid nitrogen cold shield tube diameter, liquid nitrogen specific heat capacity, liquid nitrogen thermal conductivity, liquid nitrogen density and liquid nitrogen dynamic viscosity; Among them, in the cold insulation design of the storage tank, when calculating the heat transfer of the tank wall and bottom plate, it also includes calculating the equivalent temperature of the tank wall liquid nitrogen cold screen Equivalent temperature to the liquid nitrogen cooling screen at the bottom of the tank ; The equivalent temperature of the tank wall liquid nitrogen cold screen The calculation method is: The equivalent temperature of the liquid nitrogen cooling screen at the bottom of the tank The calculation method is: in, is the comprehensive heat transfer coefficient; is the equivalent heat transfer area of ​​the liquid nitrogen cooling screen on the tank wall; is the equivalent heat transfer area of ​​the liquid nitrogen cooling screen on the tank bottom; is the mass flow rate; is the specific heat capacity of liquid nitrogen; t1′ is the liquid nitrogen outlet temperature; is the liquid nitrogen inlet temperature; is the convective heat transfer coefficient; Liquid nitrogen tube wall thickness; is the thermal conductivity of the liquid nitrogen cooling screen tube; is the thermal conductivity of liquid nitrogen; is the density of liquid nitrogen; is the liquid nitrogen flow rate; is the diameter of the liquid nitrogen cooling screen tube; is the dynamic viscosity of liquid nitrogen.

2. The design method of the novel cryogenic liquid hydrogen storage tank according to claim 1 is characterized in that: The calculation method for the inner tank wall thickness is as follows: in, is the thickness of the inner tank wall, Calculate the thickness of the inner tank wall under the hydrostatic test condition. Calculate the thickness of the inner tank wall under operating conditions. is the minimum design thickness of the inner tank wall, is the maximum density of the storage medium under operating conditions, is the maximum density of the test medium under the water pressure test condition, is the design pressure of the inner tank, The internal pressure of the inner tank minus the weight of the top plate, is the allowable stress of the inner tank wall under operating conditions, is the allowable stress of the inner tank wall under the hydrostatic test condition, H is the highest design liquid level of liquid hydrogen, is the inner diameter of the inner tank.

3. The design method of the novel cryogenic liquid hydrogen storage tank according to claim 1 is characterized in that: The calculation method for the outer tank wall thickness is as follows: is the outer tank wall thickness, is the sum of the internal pressure, internal air pressure and adiabatic system pressure, is the inner diameter of the outer tank, c is the corrosion allowance, is the allowable stress of outer tank wall.

4. The design method of the novel cryogenic liquid hydrogen storage tank according to claim 1 is characterized in that: The inner tank bottom plate and the outer tank bottom plate each include an annular edge plate and a middle plate. The annular edge plate is arranged along the outer circle of the inner tank bottom plate or the outer tank bottom plate and is formed by overlapping a plurality of edge plate units. The middle plate is arranged inside the annular edge plate and is formed by overlapping a plurality of middle plate units. The calculation method of the inner tank bottom plate thickness is as follows: Inner tank annular edge plate thickness: Minimum width of inner tank annular edge plate: is the thickness of the inner tank annular edge plate, is the thickness of the bottom ring of the inner tank wall, is the minimum width of the inner tank annular edge plate, and H is the maximum design level of liquid hydrogen; The calculation method for the outer tank bottom plate thickness is as follows: Thickness of outer tank annular edge plate: Minimum width of outer tank annular edge plate: is the thickness of the outer tank annular edge plate, is the thickness of the bottom ring of the outer tank wall, is the minimum width of the outer tank annular edge plate, and H is the maximum design liquid level of liquid hydrogen.

5. The design method of the novel cryogenic liquid hydrogen storage tank according to claim 1 is characterized in that: The calculation method for the thickness of the inner tank and outer tank top plate is: Spherical top: Buckling calculation: is the top plate thickness, is the top plate thickness of the spherical roof, Calculate the top plate thickness for buckling, is the internal pressure minus the top plate gravity, is the curvature radius of the top plate, is the external load, is the elastic modulus, is the allowable stress of the top plate, is the weld joint coefficient of the weld.

6. The design method of the novel cryogenic liquid hydrogen storage tank according to claim 1 is characterized in that: The calculation method for the daily evaporation rate of a storage tank is: in, is the daily evaporation rate, is the latent heat of vaporization of liquid hydrogen, is the volume corresponding to the maximum design liquid level of the storage tank, is the density of liquid hydrogen, is the total heat transfer of the tank.

7. The design method of the novel cryogenic liquid hydrogen storage tank according to claim 6 is characterized in that: Total heat transfer of storage tank for: in, is the heat transfer of the inner tank top plate, is the heat transfer of the inner tank wall, is the heat transfer of the inner tank bottom plate; The calculation method for the heat transfer of the inner tank top plate is: in, is the heat transfer of the inner tank top plate, is the outer surface area of ​​the inner tank top plate, is the outer surface temperature of the inner tank top plate, is the inner surface temperature of the inner tank top plate, is the thickness of the inner tank top plate, is the thermal conductivity of the inner tank top plate; The calculation method for the heat transfer of the inner tank wall is: is the heat transfer of the inner tank wall, is the equivalent temperature of the liquid nitrogen cooling screen on the tank wall, is the liquid hydrogen storage temperature, is the height of the inner tank wall, is the heat transfer coefficient of the inner tank wall surface, is the thermal conductivity of each layer of insulation material on the tank wall, is the diameter of the inner tank, The corresponding diameter of each layer of insulation material on the tank wall; The heat transfer calculation method of the inner tank bottom plate is: is the heat transfer of the inner tank bottom plate, is the equivalent temperature of the liquid nitrogen cooling screen at the bottom of the tank, is the liquid hydrogen storage temperature, is the surface area of ​​the base plate, is the thermal conductivity of the insulation material of the bottom plate and each layer of the tank bottom, It is the thickness of the tank bottom and each layer of insulation material.

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