CN218468796U - Liquid hydrogen underground storage system - Google Patents

Abstract

The utility model provides a liquid hydrogen underground storage storehouse system, it includes the storehouse body and water injection unit. The reservoir body is buried underground and comprises an inner metal sealing layer, a heat insulation layer, a supporting layer and a water-containing rock-soil layer which are sequentially arranged from inside to outside; the inside encapsulation liquid hydrogen of interior metal seal layer, the water-bearing rock-soil layer is for being located the outside saturated rock-soil layer that forms through the water injection of supporting layer, and the water injection unit carries out even water injection to water-bearing rock-soil layer through locating the underground manifold of water-bearing rock-soil layer week side to make water-bearing rock-soil layer form closed frozen soil circle in the liquid hydrogen storage process and leak in order to reduce liquid hydrogen, and support the storehouse body jointly with the supporting layer. The liquid hydrogen is prevented from being gasified through the heat insulation of the heat insulation layer, and the inner metal sealing layer and the water-containing rock-soil layer form double sealing, so that the leakage amount of the stored liquid hydrogen is effectively reduced, the large-capacity and low-cost hydrogen storage is realized by utilizing an underground structure, and the hydrogen storage device can be used for storing other low-temperature media such as liquid nitrogen, liquefied Natural Gas (LNG) and the like.

Description

Liquid hydrogen underground storage system

Technical Field

The utility model relates to a hydrogen stores technical field, in particular to liquid hydrogen underground storage storehouse system.

Background

The hydrogen has the characteristics of greenness, wide sources, large mass energy density and the like, and is a good energy storage medium and an energy carrier in a future renewable energy supply system. However, the volume energy density of hydrogen is low, which causes the problems of high storage and transportation cost, poor economy of hydrogen terminal utilization and the like. The cheap and safe hydrogen storage means is one of the bottlenecks restricting the large-scale development of the hydrogen energy industry, so the construction of a hydrogen energy storage system needs a hydrogen storage technology under high energy density. The mainstream hydrogen storage technology comprises high-pressure gaseous state, low-temperature liquefaction, metal solid storage and other modes, wherein the volume energy density of the liquid hydrogen storage mode is the largest and is 845 times that of gaseous hydrogen, and the liquid hydrogen storage mode is suitable for long-distance and large-capacity storage and is one of hot spots of research in the field of hydrogen energy storage. However, since liquid hydrogen has a low boiling point (20K) and is easily evaporated during storage, the liquid hydrogen storage container needs to have excellent heat insulation to reduce vaporization of liquid hydrogen due to heat leakage of the system, which results in a very large volume of the liquid hydrogen storage container and additional equipment for refrigeration, vacuum, monitoring, etc.

Liquid hydrogen is currently stored primarily in ground storage tanks. The storage tank adopts a double (multi) layer structure, and the interlayer is vacuum heat insulation or filling heat insulation material so as to reduce the heat transfer of liquid hydrogen in the tank. The pure high vacuum degree heat insulation layer has the advantages of simple and compact structure, small heat capacity and the like, is suitable for small liquefied natural gas storage, small amount of liquid oxygen, liquid nitrogen, liquid hydrogen and small amount of short-term liquid hydrogen storage, and is generally rarely adopted in large storage tanks because the high vacuum degree is difficult to obtain and maintain; the multi-screen heat insulation is a great improvement of multi-layer heat insulation, has the advantages of very excellent heat insulation performance, small heat capacity, light weight, quick heat balance, complex structure and high cost, and is generally suitable for small storage containers of liquid hydrogen and liquid nitrogen; vacuum degree required by filling heat insulation of vacuum powder and the like is not high, and heat insulation performance is two orders of magnitude better than that of accumulation heat insulation, so that the vacuum powder and the like are widely used in large and medium-sized low-temperature liquid storage, such as Liquefied Natural Gas (LNG) storage, liquid oxygen and liquid nitrogen transportation equipment and large-volume liquid hydrogen shipping equipment, and the biggest defects of the vacuum powder and the like are that the distance between heat insulation interlayers is required to be large, and the structure is complex and heavy.

Underground storage of liquid hydrogen has not been reported. By taking the underground cave or rock gap storage technology of natural gas, shale gas, hydrogen, compressed air and LNG (liquefied natural gas)/LPG (liquefied petroleum gas) as a reference, the development of the liquid hydrogen underground storage technology is a feasible research direction. The underground storage has large capacity, lower manufacturing cost and operating cost, and is durable and high in safety although one-time investment is large. However, since the storage of natural caverns or salt caverns is limited by geographical conditions, the conditions such as the formation structure, the distribution of underground water, the seismic intensity and the like need to be considered. In addition, the formation temperature is generally high, and the liquid hydrogen temperature is difficult to maintain under the condition of not adopting heat insulation, so the method is not suitable for storing the liquid hydrogen.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that the underground storage of liquid hydrogen cannot be realized in the prior art.

In order to solve the technical problem, the utility model provides a liquid hydrogen underground storage system, which comprises a storage body, wherein the storage body is buried underground, and the storage body comprises an inner metal sealing layer, a heat insulation layer, a supporting layer and a water-containing rock-soil layer which are sequentially arranged from inside to outside; the inner part of the inner metal sealing layer is used for packaging liquid hydrogen; the heat insulation layer is respectively connected with the inner metal sealing layer and the supporting layer through adhesives so as to insulate liquid hydrogen in the inner metal sealing layer; the supporting layer is used for improving the supporting strength of the library body; the water-containing rock-soil layer is a saturated rock-soil layer which is positioned outside the supporting layer and is formed by water injection, so that a closed frozen soil ring is formed in the hydrogen storage process to reduce liquid hydrogen leakage, and the water-containing rock-soil layer and the supporting layer support the reservoir body together; the water injection unit, its include the female pipe in ground and with the underground manifold of the female pipe intercommunication in ground, underground manifold is around locating the week side on moisture rock-soil layer is in order to be used for right moisture rock-soil layer carries out even water injection.

Optionally, the thickness of the heat-insulating layer is determined by calculation according to an allowable value of daily evaporation amount of liquid hydrogen in the inner metal sealing layer.

Optionally, the supporting layer includes, but is not limited to, one or more of reinforced concrete, prestressed concrete, modified concrete, refractory bricks, and the like.

Optionally, the thickness of the support layer is determined from the confining pressure of the reservoir, the temperature gradient, the local seismic intensity and the allowable stress calculated from the physical properties of the frozen earth and the support layer material.

Optionally, the underground liquid hydrogen storage system further comprises a ground heat barrier layer laid on the corresponding ground area above the reservoir body.

Optionally, the liquid hydrogen underground storage system further comprises an injection-production pipeline unit, wherein the injection-production pipeline unit comprises an injection-production pipeline and an injection-production/discharge valve group arranged on the injection-production pipeline.

Optionally, the injection and production pipeline comprises a low-position injection and production pipe and a high-position injection and production pipe, and the low-position injection and production pipe is inserted into the bottom of the inner cavity of the inner metal sealing layer and is used for injecting and producing liquid hydrogen; the high-position injection and discharge pipe is inserted into the upper part of the inner cavity of the inner metal sealing layer and is used for injecting liquid hydrogen and discharging gasified hydrogen.

Optionally, an injection production/discharge valve group is arranged on each of the low-level injection production pipe and the high-level injection discharge pipe, and the injection production/discharge valve group comprises a valve component base, and a safety valve group, a flow control valve group and an instrument valve which are arranged on the valve component base; the safety valve group comprises a safety relief valve, a rupture disk and a safety device shutoff valve which are sequentially connected in series on the valve component base.

Optionally, the liquid hydrogen underground storage system further comprises a hydrogen leakage monitoring unit, wherein the hydrogen leakage monitoring unit comprises a leak detector, a gas collecting hood, a gas guide pipe penetrating through the gas collecting hood, and a grid pore sieve and a rain-proof hood which are respectively arranged at two ends of the gas guide pipe, the grid pore sieve is positioned in the gas collecting hood, and the rain-proof hood is positioned outside the gas collecting hood; the part of the air duct, the grid air hole sieve and the gas collecting hood are buried underground, and the other part of the air duct, the rain cover and the leak detector are arranged on the ground.

Optionally, the liquid hydrogen underground storage system further comprises a measurement and control unit, wherein the measurement and control unit comprises a plurality of first temperature sensors arranged at different height positions of the peripheral rock-soil layer and the hydrous rock-soil layer, a plurality of second temperature sensors arranged at different height positions in the inner metal sealing layer, and pressure sensors arranged on the injection-production/discharge valve group.

According to the above technical scheme, the beneficial effects of the utility model are that:

the utility model provides a liquid hydrogen underground storage storehouse system, it includes the storehouse body and water injection unit. The reservoir body is buried underground and comprises an inner metal sealing layer, a heat insulation layer, a supporting layer and a water-containing rock-soil layer which are sequentially arranged from inside to outside; the inside of interior metal seal layer is used for the encapsulation liquid hydrogen, and thermal-insulated heat preservation is used for insulating against heat to the intraformational liquid hydrogen of interior metal seal, and the supporting layer is used for improving the support intensity of the storehouse body, the water bearing rock-soil layer is for lieing in the supporting layer outside the saturated rock-soil layer that forms through the water injection, and the water injection unit carries out even water injection to water bearing rock-soil layer through around locating the underground manifold that contains water rock-soil layer week side to make water bearing rock-soil layer form closed soil freezing circle in the liquid hydrogen storage process and leak in order to reduce liquid hydrogen, and support the storehouse body jointly with the supporting layer. The liquid hydrogen is prevented from being gasified through heat insulation of the heat insulation layer, double sealing is formed through the inner metal sealing layer and the water-containing rock-soil layer, the leakage amount of the stored liquid hydrogen is effectively reduced, large-capacity and low-cost hydrogen storage is realized by utilizing an underground structure, and the hydrogen storage tank can be used for storing other low-temperature media such as liquid nitrogen and Liquefied Natural Gas (LNG).

Drawings

Fig. 1 is a schematic structural view of a liquid hydrogen underground storage system provided by the present application.

Fig. 2 is a schematic structural diagram of an injection-production/discharge valve group in the liquid hydrogen underground storage system provided by the application.

Fig. 3 is a schematic structural diagram of a hydrogen leakage monitoring unit in a liquid hydrogen underground storage system provided by the application.

Fig. 4 is a temperature distribution diagram of a simulation model of a liquid hydrogen underground storage system provided by the present application.

The reference numerals are illustrated below:

10. a library body; 11. an inner metal seal layer; 12. a heat insulation layer; 13. a support layer; 14. an aqueous rock-soil layer; 20. a water injection unit; 21. a ground main pipe; 22. a subsurface manifold; 30. an injection and production pipeline unit; 31. a low-level injection and production pipe; 32. high-position pipe injection and discharge; 33. an injection production/discharge valve group; 331. a safety relief valve; 332. a rupture disk; 333. the safety device shuts off the valve; 334. a flow regulating valve; 335. a flow shutoff valve; 336. a primary sampling valve of the instrument; 337. a secondary sampling valve of the instrument; 40. a hydrogen leakage monitoring unit; 41. a gas-collecting hood; 42. a gas-guide tube; 43. a grid air hole sieve; 44. a rain cover; 50. a first temperature sensor; 60. a second temperature sensor; 70. a ground thermal barrier layer.

Detailed Description

Exemplary embodiments that embody features and advantages of the present invention will be described in detail in the following description. It is to be understood that the invention is capable of other and different embodiments and its several details are capable of modification without departing from the scope of the invention, and that the description and drawings are to be regarded as illustrative in nature and not as restrictive.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

For further explanation of the principles and construction of the present invention, reference will now be made in detail to the preferred embodiments of the present invention, which are illustrated in the accompanying drawings.

Referring to fig. 1, the present application provides an underground liquid hydrogen storage system, which can be used for storing other cryogenic liquid media such as liquid nitrogen, LNG (liquefied natural gas), LPG (liquefied petroleum gas), etc. The liquid hydrogen underground storage system comprises a storage body 10 and a water injection unit 20.

The storehouse body 10 is buried underground, is not limited to spherical, cylindrical, square and the like in appearance, comprises a four-layer lining structure, and specifically, the storehouse body 10 is sequentially provided with an inner metal sealing layer 11, a heat insulation layer 12, a supporting layer 13 and a water-containing rock soil layer 14 from inside to outside.

The inner metal sealing layer 11 is a closed cavity formed by plates with a corrugated structure, the plates with the corrugated structure include but are not limited to corrugated aluminum plates or stainless steel plates with the specification of 304 grade and above, and if the stainless steel plates with the specification of 304 grade and above are adopted, aluminum powder is coated on the inner wall of the inner metal sealing layer 11; the liquid hydrogen is encapsulated in the inner metal sealing layer 11, the corrugated structure of the inner metal sealing layer 11 can effectively eliminate the stress concentration brought to the inner metal sealing layer 11 by the temperature change of the liquid hydrogen, and the aluminum plate or the stainless steel plate with the specification of 304 grade or above and with the inner wall coated with aluminum powder can reduce the radiant heat flux between each layer of the warehouse body 10.

The heat insulation layer 12 is arranged between the inner metal sealing layer 11 and the supporting layer 13, is used for insulating liquid hydrogen in the inner metal sealing layer 11, is a main heat insulation measure of the storehouse body 10, and is bonded with the inner metal sealing layer 11 and the supporting layer 13 through bonding agents respectively so as to reduce heat transfer increase caused by water inflow in an interlayer gap. Specifically, the heat-insulating layer 12 is a heat-insulating material with a certain thickness, the heat-insulating material is a porous medium heat-insulating material such as high-density polyurethane, pearl wool and the like which is not limited to high heat resistance, and the thickness of the heat-insulating layer 12 can be determined by calculation according to an allowable value of the daily evaporation capacity of the liquid hydrogen in the inner metal sealing layer, and usually, the allowable value of the daily evaporation capacity of the liquid hydrogen does not exceed 5% of the total mass of the liquid hydrogen. It is understood that, when the underground storage system of the present application is used for storing other cryogenic liquid media such as liquid nitrogen, LNG (liquefied natural gas), LPG (liquefied petroleum gas), etc., the thickness of the thermal insulation layer 12 can also be determined by calculation according to the allowable value of the daily evaporation amount of the cryogenic liquid medium stored inside the inner metal sealing layer.

The support layer 13 is arranged outside the heat insulation layer 12 and is made of high-strength material to bear the main positive pressure and shearing force of the storehouse body 10. The supporting layer 13 is one or a combination of several materials including but not limited to reinforced concrete, prestressed concrete, modified concrete, refractory bricks and the like; the thickness of the supporting layer 13 is designed according to the confining pressure, the temperature gradient, the frost heaving stress of the underground rock-soil layer and the grade of the local seismic intensity of the reservoir 10, so that the confining pressure, the frost heaving stress of the frost soil and the potential stress damage caused by earthquake can be balanced, the deformation of the reservoir 10 is ensured to be in a safe range, and the reservoir 10 is prevented from cracking during the hydrogen storage operation. It will be appreciated that, in the case of a large-sized library body 10, the support layer 13 further includes lateral support and longitudinal support to enhance the strength of the entire library body 10.

The hydrous rock-soil layer 14 is formed by injecting water into the rock-soil layer positioned outside the supporting layer 13 so as to saturate the rock-soil layer outside the supporting layer 13, and after liquid hydrogen is injected into the inner metal sealing layer 11, the part of saturated rock-soil layer forms a compact frozen-ice ring in a low-temperature environment, so that the rock-soil layer becomes a closed frozen-soil ring, hydrogen leakage is reduced, and the hydrous rock-soil layer and the supporting layer 13 jointly support the reservoir body 10.

In terms of leakage control, the reservoir body 10 acts as a first leakage-proof barrier to the liquid hydrogen stored therein through the inner metal sealing layer 11, and forms a second leakage-proof barrier through the hydrous rock-soil layer 14; in terms of the strength of the storehouse body 10, besides the main supporting function of the supporting layer 13, the corrugated structure of the inner metal sealing layer 11 effectively eliminates stress concentration caused by temperature change and the supporting and supporting of the supporting layer 13 by the hydrous rock-soil layer 14; in the aspect of heat leakage rate control, the heat insulation layer 12 is used as a main heat transfer resistance, the inner metal sealing layer 11 is made of aluminum plates or stainless steel plates coated with aluminum powder on the inner wall to reduce the radiant heat flux between the storeroom 10 layers, and the heat insulation layer 12 is connected with the inner metal sealing layer 11 and the supporting layer 13 in a bonding mode, so that the heat transfer increase caused by water entering gaps between the layers is further reduced.

Furthermore, because of the influence of heat leakage, the temperature of the area above the warehouse 10 near the ground is low, in order to reduce the influence of low temperature on vegetation on the upper ground, installed equipment and the damage to operators, a ground thermal barrier layer 70 is laid on the ground of the area, the thickness of the ground thermal barrier layer 70 is determined after design calculation according to the safety of the ground equipment and the operators, and the thickness of the ground thermal barrier layer 70 is usually set within the temperature range of 10 ℃ to 25 ℃.

The water injection unit 20 comprises a ground main pipe 21 arranged on the ground and an underground manifold 22 communicated with the ground main pipe 21 and arranged underground, wherein the underground manifold 22 is wound on the periphery of the hydrous rock-soil layer 14 to form at least one annular pipeline so as to facilitate uniform water injection on the hydrous rock-soil layer 14.

The liquid hydrogen underground storage system further comprises an injection and production pipeline unit 30, and the injection and production pipeline unit 30 comprises an injection and production pipeline and an injection and production/discharge valve group 33 arranged on the injection and production pipeline.

Specifically, the injection and production pipeline is of a double-layer structure, and the interlayer is vacuumized to reduce heat transfer loss. Wherein, the injection and production pipeline comprises a low-position injection and production pipe 31 and a high-position injection and production pipe 32; the low-level injection-production pipe 31 is inserted into the bottom of the inner cavity of the inner metal sealing layer 11 and is mainly used for injecting and producing liquid hydrogen; the high position injection and discharge pipe 32 is inserted into the upper part of the inner cavity of the inner metal sealing layer 11 for injecting liquid hydrogen and discharging gasified hydrogen. Further, the injection and production piping is provided with a flame arrester to prevent the flame front from spreading toward the bank body 10 when a fire occurs from the outside. It is understood that the ground portion of the underground liquid hydrogen storage system may be provided with an auxiliary refrigeration system, and when the pressure of the liquid hydrogen in the storage body 10 is raised to a certain value and the gasified hydrogen is discharged from the high-level discharge pipe 32, the gasified hydrogen is re-liquefied in time by the auxiliary refrigeration system and then injected into the storage body 10, but this is not a necessary component.

The low-level injection and production pipe 31 and the high-level injection and production pipe 32 are both provided with an injection and production/discharge valve group 33, and the injection and production/discharge valve group 33 is installed by adopting an integrated ground base and comprises a safety valve group, a flow control valve group, an instrument valve group and a valve component base.

Referring to fig. 2, the safety valve set includes a safety relief valve 331, a rupture disk 332, and a safety device shutoff valve 333, and the safety relief valve 331 and the rupture disk 332 are connected to the valve assembly base through the safety device shutoff valve 333. The safety pressure relief valve 331 and the rupture disk 332 form two-stage safety pressure relief, and the two can be connected in series or in parallel, so that the storage is protected safely. Specifically, the starting pressure (upper limit I value) of the safety relief valve 331 is higher than the upper limit of the operation pressure of the reservoir but lower than the detonation pressure (upper limit II value) of the rupture disk 332, the safety relief valve 331 can adopt but is not limited to a spring prepressing type, the prepressing pressure is adjusted to the I value, when the pressure of the reservoir is abnormally increased to the upper limit I value due to gasification and the like, the safety relief valve 331 is automatically opened to perform exhaust and pressure relief, and the exhaust pipe is installed at a high position for good ventilation; the rupture disk 332 is of a membrane type, when the reservoir pressure continues to rise to a value II, the membrane is ruptured to release pressure, and the pressure release exhaust pipe is installed at a high place to achieve good ventilation (the upper limit value I/II is set according to the reservoir design pressure, or related standards can be referred to, such as a rupture disk 332 safety device for a national standard GB/T16974 gas cylinder, GB/T33215 gas cylinder safety pressure release, TSG 23 gas cylinder safety technical regulations and the like). The safety device shut-off valve 333 is for isolating the reservoir body 10 from the safety relief valve 331 and the rupture disk 332, and the safety device shut-off valve 333 is to be in a fully open position and is provided with a lock device. When the safety valve member needs to be serviced for maintenance or other purposes, the safety shut-off valve 333 can be closed and the safety shut-off valves 333 on the low level injection and production pipe 31 and the high level injection and discharge pipe 32 cannot be closed at the same time.

The flow control valve block includes a flow control valve 334 and a flow shutoff valve 335, the flow control valve and the flow shutoff valve 335 are connected in series and attached to the valve block base, and injection flow and rate are controlled by the flow control valve 334.

The meter valve block includes a meter primary sampling valve 336 and a meter secondary sampling valve 337 mounted on the valve assembly base and connected in series.

In terms of pressure safety control, the injection-production/discharge valve group 33 is arranged on both the low-level injection-production pipe 31 and the high-level injection-discharge pipe 32, so that double pressure safety protection under different pressures is formed. Since the pressure inside the reservoir 10 must be controlled within the allowable pressure range, the pressure inside the reservoir 10 is too high or too low (negative pressure occurs), which is a potential hazard to the reservoir 10. Many factors that affect reservoir pressure, such as heat ingress causing evaporation of the liquid, rapid flashing of the liquid during filling, atmospheric pressure drop, or faulty operation, can cause the pressure in the reservoir 10 to rise; in addition, if the liquid is discharged or evacuated from the reservoir at a very high speed, a negative pressure may be formed in the reservoir. The excessive evaporation gas in the storage tank is conveyed to external connection equipment or a system through a flow regulating valve 334 to maintain the pressure in the storage tank to be stable; the safety relief valve 331 and the rupture disk 332 form double and two-stage safety control and protection for the pressure in the warehouse body 10, and under the unexpected condition that the evaporation gas suddenly increases or the evaporation gas cannot be consumed outside, the safety relief valve 331 is automatically opened to vent the evaporation gas, and the rupture disk 332 is ruptured to relieve the pressure under the dangerous condition.

The safety protection device of the storage bank must have enough discharge capacity, and the discharge capacity required by the safety discharge device is calculated according to the chemical engineering technical design manual or the following formula:

in the formula, q _v -m 3/h with respect to the flow rate of air (15.5 ℃,101.35 kPa);

Φ -Total Heat flux, kW;

gamma-the enthalpy of vaporization phase change of the storage liquid, kJ/kg;

t-the thermodynamic temperature of the gas at the inlet of the safety valve, K;

m-the relative molecular mass of the gas.

Referring to fig. 3, in order to monitor the leakage of hydrogen, the underground liquid hydrogen storage system further includes a hydrogen leakage monitoring unit 40. The hydrogen leakage monitoring unit 40 comprises a leak detector, a gas collecting hood 41, a gas guide tube 42 penetrating the gas collecting hood 41, and a grid pore sieve 43 and a rain-proof hood 44 respectively arranged at two ends of the gas guide tube 42, wherein the grid pore sieve 43 is positioned in the gas collecting hood 41, the rain-proof hood 44 is positioned outside the gas collecting hood 41, the gas guide tube 42 is respectively arranged at the lower section and the upper section, the underground section of the gas guide tube 42, the gas collecting hood 41 and the grid pore sieve 43 form an underground part of the hydrogen leakage monitoring unit 40 buried underground, and the upper section of the gas guide tube 42, the rain-proof hood 44 and the leak detector form an overground part of the hydrogen leakage monitoring unit 40 exposed out of the ground. The leaked hydrogen enters the gas guide tube 42 through the air hole screen mesh lattice of the underground part, the leaked gas collecting hood 41 is used for collecting the leaked hydrogen in a certain range, the amplification effect is achieved, and the underground part of the hydrogen leakage monitoring unit 40 can be arranged in different height areas of different areas by adjusting the length of the underground part of the gas guide tube 42, so that the storage area is effectively monitored; after the leak detector is installed and detects hydrogen, a signal is transmitted to a signal acquisition and control system to trigger alarm or relevant emergency operation disposal; rain-proof cover 44 is used for preventing rain and snow or foreign matter from getting into air duct 42 and resulting in the passageway to block, and rain-proof cover 44 can also strengthen the diffusion of hydrogen to the air simultaneously, reduces because of the potential risk of blasting that the hydrogen gathering caused.

Further, the liquid hydrogen underground storage system further comprises a measurement and control unit, wherein the measurement and control unit comprises a first temperature sensor 50, a second temperature sensor 60 and a pressure sensor.

The first temperature sensor 50 is arranged at different heights of the peripheral rock soil and the hydrous rock soil layer 14, and is used for monitoring the three-dimensional temperature distribution condition of the peripheral rock soil and the hydrous rock soil layer 14, so that the underground three-dimensional temperature distribution condition and the heat conduction condition of the storage system can be conveniently known.

The second temperature sensor 60 is disposed at different height positions of the inner cavity of the inner metal sealing layer 11 to measure the temperature of the liquid hydrogen in the inner metal sealing layer 11, and determine the liquid hydrogen stratification condition according to the temperature gradient with reversed height. Because the liquid hydrogen in the reservoir body 10 is not properly controlled in filling or the vertical density (temperature) of the liquid hydrogen is deviated due to heat leakage, the natural convection of the liquid hydrogen is aggravated, and the gasification rate is increased, so that the density (temperature) stratification of the liquid hydrogen in the reservoir is prevented, which is an important means for ensuring the storage safety of the liquid hydrogen. By providing temperature sensors at different heights within the inner metallic containment layer 11, it is determined whether delamination has occurred by measuring the temperature gradient in the inner vertical direction within the inner metallic containment layer 11. And when the vertical temperature gradient of the liquid layer is more than 0.2K/m (the value is a recommended value and can be selected according to design requirements, safety requirements and the like), the delamination is considered to occur.

A pressure sensor is mounted on the injection/extraction valve block 33 for measuring the pressure value of the reservoir.

After signal data lines of the whole liquid hydrogen underground storage system are concentrated nearby, the signal data lines are led out to the ground through a plurality of guide pipes, and are connected to a PLC (programmable logic controller) or DCS (distributed control system) signal acquisition and control system for data monitoring display and control linkage use. The control system adopts a centralized control mode, can realize the acquisition and logic judgment of signal data and the operation and operation of valves and equipment, and has an automatic control function.

The using procedure of the liquid hydrogen underground storage system mainly comprises four steps of displacement, precooling, liquid injection and storage. When the density of the injected medium is greater than that of the medium in the tank in the processes of replacement and injection, top injection is adopted; when the density of the medium in the tank is smaller than or close to the density of the medium in the tank, a bottom loading method is adopted.

Specifically, the "displacement" step is performed by displacing the air in the reservoir from its initial state with an inert gas, including but not limited to nitrogen. The replacement gas is injected into the lower part of the inner cavity of the inner metal sealing layer 11 through the low-level injection and production pipe 31, and the mixed gas is discharged through the high-level injection and production pipe 32 until the volume fraction of oxygen in the discharged mixed gas is monitored to be not less than 0.5% (or is referred to corresponding standards, such as GB50516 hydrogenation station technical specification, GB 50156 automobile refueling and gas filling hydrogenation station technical specification, GB/T34584 hydrogenation station safety technical specification and the like). Through the replacement step, explosion caused by direct hydrogen entering into the inner cavity of the inner metal sealing layer 11 and mixing with original air in the cavity is avoided, and potential safety hazards are reduced.

In the replacement process, the water injection unit 20 is used for injecting water into the hydrous rock-soil layer 14 until the hydrous rock-soil layer is saturated; the hydrous rock-soil layer 14 is saturated, liquid nitrogen is injected into the inner cavity of the inner metal sealing layer 11 through the low-position injection-production pipe 31 to pre-cool the storage system, and gasified nitrogen is discharged through the high-position injection-production pipe 32. The process gradually cools the reservoir body 10 to the temperature of liquid nitrogen, and the nearby saturated rock-soil layer is gradually cooled to the temperature below the freezing point to form a compact ice ring, so that the step of precooling is completed.

And standing for a period of time after the pre-cooling step is finished, and starting to perform the liquid injection step when the data of each temperature measuring point of the system is stable. Liquid hydrogen is slowly injected through the high-position injection and drainage pipe 32, and is gasified to generate hydrogen in the injection process of the liquid hydrogen, so that the pressure of the inner cavity of the inner metal sealing layer 11 is gradually increased, meanwhile, the temperature of the reservoir body 10 is continuously reduced to the boiling point temperature of the liquid hydrogen, and liquid nitrogen is discharged through the low-position injection and drainage pipe 31 under the action of pressure; when liquid hydrogen appears at the pipe orifice of the low-position injection and production pipe 31 in the inner metal sealing layer 11, the liquid hydrogen injection channel is switched to the low-position injection and production pipe 31, the hydrogen discharge channel is changed to the high-position injection and production pipe 32, the formal injection and storage of the liquid hydrogen are started until the step of storing the liquid hydrogen in the whole reservoir body 10 is completed, and the capacity of the stored liquid hydrogen is known by monitoring the liquid level condition.

It should be noted that, the application program of the whole liquid hydrogen underground storage system needs to monitor the data of each temperature measuring point and pressure measuring point, know the change condition of temperature and pressure, prevent the occurrence of serious accidents such as quenching cracking, pressure sudden-rise damage and the like, and estimate the heat leakage condition and the evaporation condition of the system. In addition, in order to prevent the liquid hydrogen stratification, i.e. the deviation of the vertical density (temperature) of the liquid hydrogen, the correct liquid filling sequence is adopted during the 'filling' period, and the stratification is adopted during the 'storage' period, and the liquid hydrogen density (temperature) in the inner metal sealing layer 11 is uniformly distributed by adopting a circulating stirring manner through the ground part which is provided with an external pump and is connected with the high-position filling and discharging pipe 32 and the low-position filling and discharging pipe.

The deactivation sequence of the liquid hydrogen underground reservoir system differs according to short-term deactivation and long-term deactivation or abandonment. When the system is stopped for a short time, considering that the peripheral frozen soil layer ice ring of the storage warehouse can have cracks in the freezing and thawing process to influence the tightness when the storage warehouse system is used again, liquid nitrogen needs to be injected into the storage warehouse for cold insulation during the period of stopping hydrogen storage, and the low-temperature state of the storage warehouse and the freezing state of the peripheral frozen soil ice ring are maintained; if the reservoir needs to be stopped or discarded for a long time in special cases, the residual liquid hydrogen or hydrogen in the reservoir body 10 needs to be evaporated and replaced by inert gas such as nitrogen or carbon dioxide according to the step of 'replacement' in the reservoir using procedure until the content of hydrogen in the discharged mixed gas is lower than the explosion interval.

The present application takes a spherical library 10 with a diameter of 1m as an example for heat transfer simulation. The specific setting data of the simulation model are as follows: the diameter of the spherical storage tank is 1m, the heat insulation layer is 20cm, the concrete supporting layer is 1310cm, and the external frozen soil is saturated frozen soil; the storage model is located in 10m underground, and a two-dimensional space of a calculation domain is 100m multiplied by 60 m; the ground temperature is 293K, and the liquid hydrogen parameter is 1.5bar.a/20K. Please refer to fig. 4 for the temperature distribution. As can be seen from the temperature field data in FIG. 4, the heat insulation layer has good heat insulation effect when the external temperature of the heat insulation layer is about 200K. Reservoir wall heat flux density 61.55W/m ² Heat leakage in folding775W (. Apprxeq.0.75% daily evaporation rate).

The utility model provides a liquid hydrogen underground storage storehouse system, it includes storehouse body 10 and water injection unit 20. The reservoir body 10 is buried underground and comprises an inner metal sealing layer 11, a heat insulation layer 12, a supporting layer 13 and a water-containing rock-soil layer 14 which are sequentially arranged from inside to outside; the inside of the inner metal sealing layer 11 is used for packaging liquid hydrogen, the heat insulation layer 12 is used for insulating heat of the liquid hydrogen in the inner metal sealing layer 11, the supporting layer 13 is used for improving the supporting strength of the reservoir body 10, the water-containing rock-soil layer 14 is a saturated rock-soil layer which is located outside the supporting layer 13 and formed by water injection, and the water injection unit 20 evenly injects water to the water-containing rock-soil layer 14 through an underground manifold 22 which is wound around the periphery of the water-containing rock-soil layer 14, so that the water-containing rock-soil layer 14 forms a closed frozen soil ring in the hydrogen storage process to reduce liquid hydrogen leakage, and supports the reservoir body 10 together with the supporting layer 13. The liquid hydrogen is prevented from being gasified through the common heat insulation of the heat insulation layer 12 and the water-containing rock-soil layer 14, double sealing is formed through the inner metal sealing layer 11 and the water-containing rock-soil layer 14, the leakage amount of the stored liquid hydrogen is effectively reduced, large capacity and low cost hydrogen storage are realized by utilizing an underground structure, the adopted materials are mostly common industrial materials, purchase and maintenance cost are low, reduction of construction, maintenance cost and liquid hydrogen storage cost are facilitated, and large-scale application and popularization are facilitated.

While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims (9)

1. A liquid hydrogen underground storage system, comprising:

the reservoir body is buried underground and comprises an inner metal sealing layer, a heat insulation layer, a supporting layer and a water-containing rock-soil layer which are sequentially arranged from inside to outside; the inner part of the inner metal sealing layer is used for packaging liquid hydrogen; the heat insulation layer is respectively connected with the inner metal sealing layer and the supporting layer through adhesives so as to insulate liquid hydrogen in the inner metal sealing layer; the supporting layer is used for improving the supporting strength of the library body; the water-containing rock-soil layer is a saturated rock-soil layer which is positioned outside the supporting layer and is formed by water injection, so that a closed type frozen soil ring is formed in the liquid hydrogen storage process to reduce liquid hydrogen leakage, and the water-containing rock-soil layer and the supporting layer support the reservoir body together;

the water injection unit, its include the female pipe in ground and with the underground manifold of the female pipe intercommunication in ground, underground manifold is around locating the week side on moisture rock-soil layer is in order to be used for right moisture rock-soil layer carries out even water injection.

2. The underground liquid hydrogen storage system according to claim 1, wherein the thickness of the heat insulating layer is determined according to an allowable value of daily evaporation of liquid hydrogen in the inner metal sealing layer.

3. A liquid hydrogen underground storage system according to claim 2, wherein the thickness of the supporting layer is determined from the confining pressure of the reservoir, the temperature gradient, the local seismic intensity, and the allowable stress calculated from the physical properties of the frozen earth, supporting layer material.

4. The system of claim 1, further comprising a ground thermal barrier layer applied to a corresponding ground area above the reservoir body.

5. The liquid hydrogen underground storage system according to claim 1, further comprising an injection-production pipeline unit, wherein the injection-production pipeline unit comprises an injection-production pipeline and an injection-production/discharge valve group arranged on the injection-production pipeline.

6. The underground liquid hydrogen storage system according to claim 5, wherein the injection and production pipeline comprises a low-level injection and production pipe and a high-level injection and production pipe, and the low-level injection and production pipe is inserted into the bottom of the inner cavity of the inner metal sealing layer for injecting and producing liquid hydrogen; the high-position injection and discharge pipe is inserted into the upper part of the inner cavity of the inner metal sealing layer and is used for injecting liquid hydrogen and discharging gasified hydrogen.

7. The underground liquid hydrogen storage system according to claim 6, wherein one injection-production/discharge valve set is arranged on each of the low-level injection-production pipe and the high-level injection-discharge pipe, and the injection-production/discharge valve set comprises a valve assembly base, and a safety valve set, a flow control valve set and an instrument valve which are arranged on the valve assembly base; the safety valve group comprises a safety relief valve, a rupture disk and a safety device shutoff valve which are sequentially connected in series on the valve component base.

8. The underground liquid hydrogen storage system according to claim 1, further comprising a hydrogen leakage monitoring unit, wherein the hydrogen leakage monitoring unit comprises a leak detector, a gas-collecting hood, a gas-guiding tube penetrating the gas-collecting hood, and a grid pore sieve and a rain-proof hood respectively arranged at two ends of the gas-guiding tube, the grid pore sieve is positioned in the gas-collecting hood, and the rain-proof hood is positioned outside the gas-collecting hood; the part of the air duct, the grid air hole sieve and the gas collecting hood are buried underground, and the other part of the air duct, the rain cover and the leak detector are arranged on the ground.

9. The liquid hydrogen underground storage system according to claim 5, further comprising a measurement and control unit including a plurality of first temperature sensors disposed at different height positions of the peripheral rock and the hydrous rock-soil layer, a plurality of second temperature sensors disposed at different height positions within the inner metal sealing layer, and pressure sensors mounted on the injection-production/discharge valve group.

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