Gas storage system and gas storage method

Abstract

The application discloses a gas storage system and a gas storage method. The gas storage system comprises a gas storage library, a gas bag, and a first gas pipe. The gas storage library has a containing cavity. The gas bag is arranged in the containing cavity and is suitable for storing hydrogen. One end of the first gas pipe is suitable for being connected with an external gas source, and the other end is connected with the gas bag. In the axial direction of the first gas pipe, the size of the gas bag is adjustable. A guide piece extends in the axial direction. At least part of the guide piece is arranged in the gas bag. Two ends of the guide piece are respectively connected with two ends of the gas bag in the axial direction. The guide piece is telescopic along the axial direction of the first gas pipe. According to the gas storage system, the guide piece and the gas bag can be integrated and follow-up, the guide piece can be ensured to be located on the central axis of the gas bag at all times, the telescopic deformation of the gas bag can be directly axially guided and radially limited, and therefore, the controllability of the deformation and the structural stability of the gas bag under the complex working conditions of a salt cave can be improved.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, and in particular to an air storage system and air storage method. Background Technology

[0002] With the global push for "dual carbon" goals, hydrogen energy, as a core component of the clean energy system, relies on breakthroughs across the entire industry chain—from production and storage to transportation and utilization—for its large-scale development. Hydrogen storage technology is particularly crucial in connecting hydrogen production with end-use applications. Underground salt cavern hydrogen storage has become a mainstream approach due to its large storage capacity, small footprint, and low cost. Existing industrial-derived salt caverns and old mining cavities possess characteristics of large volume, deep burial, and good stability. Converting them into hydrogen storage cavities allows for the reuse of waste resources, offering significant economic and environmental value, and serves as an important application platform for underground hydrogen storage.

[0003] However, existing salt caverns are mostly irregular cavities with varying inner wall roughness, local protrusions or depressions, and complex morphology due to long-term exposure to geostress and brine erosion. Furthermore, when the cavities are filled and circulated within the cavities, they are prone to lateral drift, eccentric bulging, or irregular torsion under the combined action of high-pressure hydrogen and residual brine. This can lead to unexpected contact and friction between the cavity wall and the rough inner wall of the salt cavern, resulting in localized wear or even tearing of the membrane material. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a gas storage system that can achieve integrated follow-up of the guide component and the gas bladder, ensuring that the guide component is always located on the central axis of the gas bladder. This provides the most direct axial guidance and radial limitation for the expansion and contraction deformation of the gas bladder, thereby improving the controllability of the deformation and structural stability of the gas bladder under the complex working conditions of salt caverns.

[0005] The present invention also proposes a gas storage method.

[0006] According to a first aspect of the present invention, the gas storage system comprises: a gas storage tank having a receiving cavity; an air bladder disposed within the receiving cavity, the air bladder being adapted to store hydrogen; a first gas pipe having one end adapted to be connected to an external gas source and the other end connected to the air bladder, the size of the air bladder being adjustable in the axial direction of the first gas pipe; and a guide member extending along the axial direction of the first gas pipe, at least a portion of the guide member being disposed within the air bladder, both ends of the guide member being respectively connected to both ends of the air bladder in the axial direction of the first gas pipe, and the guide member being telescopic along the axial direction of the first gas pipe.

[0007] According to the gas storage system of the present invention, by setting a guide member, the guide member and the bladder can be integrated and follow each other, ensuring that the guide member is always located on the central axis of the bladder. This can provide the most direct axial guidance and radial limit for the expansion and contraction deformation of the gas bladder, thereby improving the controllability of deformation and structural stability of the bladder under complex working conditions in salt caverns.

[0008] According to some embodiments of the present invention, the guide includes a guide sleeve and a guide rod. The guide sleeve is fixedly connected to one end of the airbag in the axial direction of the first air tube. The guide rod extends along the axial direction of the first air tube. One end of the guide rod is slidably fitted inside the guide sleeve, and the other end is fixedly connected to the other end of the airbag in the axial direction of the first air tube.

[0009] According to some embodiments of the present invention, the guide further includes: an elastic reset member, which is sleeved on the radially outer side of the guide rod and connected between the guide sleeve and the other end of the airbag.

[0010] According to some embodiments of the present invention, the elastic reset member is a spring, the spring comprising: a first elastic segment, a second elastic segment, and a third elastic segment arranged sequentially along the axial direction of the first air tube, wherein the rigidity of the first elastic segment is less than the rigidity of the second elastic segment, and the rigidity of the second elastic segment is less than the rigidity of the third elastic segment.

[0011] According to some embodiments of the present invention, an air cavity is defined between the airbag and the inner wall of the receiving cavity, and the guide extends from both ends of the airbag in the axial direction of the first air tube. An air passage is formed in the guide, one end of the air passage is adapted to be connected to an inert air source, and the other end is connected to the air cavity.

[0012] According to some embodiments of the present invention, the gas storage system further includes: a hydrogen concentration sensor disposed in the gas cavity for detecting the concentration of hydrogen in the gas cavity; and / or a first barometer disposed in the gas cavity for detecting the gas pressure in the gas cavity.

[0013] According to some embodiments of the present invention, along the direction from the inside to the outside of the airbag thickness, the airbag includes a sealing layer, a pressure-bearing layer, a transition layer, and a protective layer. The sealing layer is a composite fluorine-based nano-intercalated composite material, the pressure-bearing layer is a ceramic matrix composite material, the ceramic matrix composite material includes a three-dimensional orthogonally woven fiber preform and a ceramic composite matrix filled in the pores of the preform, the transition layer is a graphene-modified polyurethane nanocomposite material, and the protective layer is a polyimide-polytetrafluoroethylene polymer composite material.

[0014] According to some embodiments of the present invention, the gas storage system further includes: a fiber Bragg grating sensor, which is disposed between the pressure-bearing layer and the transition layer, for detecting strain changes, temperature changes and interface debonding damage at the interlayer interface.

[0015] According to some embodiments of the present invention, the gas storage system further includes a second barometer, which is disposed inside the gas bladder and is used to detect the pressure of hydrogen gas inside the gas bladder.

[0016] According to a second aspect of the present invention, a gas storage method is used in the gas storage system according to the first aspect, the method comprising: Step S1: Obtain three-dimensional morphological data of the cavity and place the airbag at a predetermined depth in the cavity; Step S2: Seal the opening of the receiving cavity and control the gas storage system to input hydrogen gas at a first preset pressure value into the airbag so that the airbag is in the deployed state; Step S3: Control the gas storage system to deliver inert gas at a second preset pressure value to the gas chamber, and confirm whether the pressure drop of the gas chamber is less than the first preset value. If yes, execute step S31; otherwise, execute step S32. Step S31: Control the gas storage system to deliver inert gas into the gas chamber so that the pressure difference between the gas chamber and the gas bag is controlled within a first preset difference range. Step S32: Confirm the location of the leak, repair the leak, and then repeat step S3. Step S4: Control the gas storage system to input or output hydrogen into the gas bag and output or input the inert gas into the gas chamber, so as to continuously control the pressure difference within the first preset difference range.

[0017] According to the gas storage method of the present invention, hydrogen storage can be achieved by simply modifying the salt cavern, and at the same time, the safety and reliability of the hydrogen storage process can be effectively guaranteed.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a gas storage system according to an embodiment of the present invention; Figure 2 yes Figure 1 Enlarged view of point A circled in the image; Figure 3 This is a partial schematic diagram of a fiber Bragg grating sensor; Figure 4 This is a flowchart of a gas storage method according to an embodiment of the present invention.

[0020] Figure label: 100. Gas storage system; 10. Gas storage tank; 11. Receiving cavity; 12. Wellbore; 20. Airbag; 21. Sealing layer; 22. Pressure-bearing layer; 23. Transition layer; 24. Protective layer; 30. First gas tube; 31. Hydrogen inlet; 32. Hydrogen outlet; 40. Guide component; 41. Guide sleeve; 42. Guide rod; 43. Elastic reset component; 44. Gas passage; 45. Inert gas inlet; 46. Inert gas outlet; 50. Hydrogen concentration sensor; 60. First barometer; 70. Fiber Bragg grating sensor; 80. Second barometer. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] The following is for reference. Figures 1-3 A gas storage system 100 according to an embodiment of the first aspect of the present invention is described.

[0023] like Figure 1 As shown, according to a first aspect embodiment of the present invention, the gas storage system 100 includes: a gas storage tank 10, an airbag 20, and a first gas pipe 30. The gas storage tank 10 has a receiving cavity 11; the airbag 20 is disposed within the receiving cavity 11 and is adapted to store hydrogen gas; one end of the first gas pipe 30 is adapted to be connected to an external gas source, and the other end is connected to the airbag 20; the size of the airbag 20 is adjustable in the axial direction of the first gas pipe 30.

[0024] Specifically, the gas storage chamber 10 is a component used to house and place the airbag 20. It should be noted that the gas storage chamber 10 in this embodiment is a salt cavern gas storage chamber 10, as shown in the reference. Figure 1 The salt cavern gas storage 10 includes: a receiving cavity 11 pre-formed at a preset location and a wellbore 12 connected to the receiving cavity 11, wherein the receiving cavity 11 is connected to the outside only through the wellbore 12.

[0025] The airbag 20 is a component used to store hydrogen. It should be noted that the airbag 20 in this embodiment is a flexible airbag 20. The flexible airbag 20 is suspended in the central area of ​​the receiving cavity 11, and a gap of 30cm-100cm is reserved between its outer wall and the inner wall of the receiving cavity 11 to form an annular area.

[0026] The first gas pipe 30 is a hydrogen transport channel between the ground and the gasbag 20. It is mainly used to transport external hydrogen into the gasbag 20 for storage, or to transport hydrogen from the gasbag 20 to the equipment for use. It should be noted that the first gas pipe 30 extends out of the salt cavern receiving cavity 11 through the well shaft 12.

[0027] The statement "the size of the airbag 20 is adjustable in the axial direction of the first trachea 30" is intended to illustrate that when the airbag 20 is inflated or when the hydrogen in the airbag 20 is expelled, the size of the airbag 20 is adjustable in the axial direction of the first trachea 30, that is, the airbag 20 can expand and contract in accordance with the amount of hydrogen.

[0028] like Figure 1 As shown, the gas storage system 100 further includes: a guide 40, which extends along the axial direction of the first air pipe 30, at least a portion of which is arranged inside the air bag 20, and both ends of the guide 40 are respectively connected to both ends of the air bag 20 in the axial direction of the first air pipe 30, and the guide 40 is telescopic along the axial direction of the first air pipe 30.

[0029] The phrase "the two ends of the guide member 40 are respectively connected to the two ends of the airbag 20 in the axial direction of the first air tube 30, and the guide member 40 is telescopic along the axial direction of the first air tube 30" can be understood as the guide member 40 can extend or retract as the airbag 20 expands and contracts. For example, when the airbag 20 is inflated, the guide member 40 can be passively stretched as the airbag 20 extends axially; when the airbag 20 is deflated and contracted, the guide member 40 is actively or passively compressed and retracted axially, pulling the two ends of the airbag body towards the middle.

[0030] The two ends of the guide member 40 are fixed to the two ends of the airbag 20 in the axial direction of the first trachea 30, which means that the change in the axial length of the airbag 20 can be transmitted to the guide member 40, and the extension and retraction stroke of the guide member 40 can also limit the maximum relative displacement of the airbag 20 at both ends in the axial direction of the first trachea 30. Thus, the axial length of the airbag 20 is always determined by the guide member 40 within a reasonable range, regardless of its inflation degree. This can effectively prevent the airbag material from yielding due to excessive stretching or the interlayer friction damage of the airbag due to excessive compression.

[0031] Optional, such as Figure 1As shown, the gas storage system 100 also includes a hydrogen input terminal 31 and a hydrogen output terminal 32, wherein one end of the first gas pipe 30 is rigidly and sealed to the hydrogen input terminal 31 and the hydrogen output terminal 32, and the other end is sealed to the gas bag 20.

[0032] According to the gas storage system 100 of the present invention, by setting the guide member 40, the guide member 40 and the bladder can be integrated and follow each other, ensuring that the guide member 40 is always located on the central axis of the bladder, thereby providing the most direct axial guidance and radial limit for the expansion and contraction deformation of the air bladder 20, thereby improving the controllability of deformation and structural stability of the bladder under complex working conditions in salt cavern.

[0033] According to some embodiments of the present invention, such as Figure 1 As shown, the guide component 40 includes a guide sleeve 41 and a guide rod 42. The guide sleeve 41 is fixedly connected to one end of the airbag 20 in the axial direction of the first air tube 30. The guide rod 42 extends along the axial direction of the first air tube 30. One end of the guide rod 42 is slidably fitted inside the guide sleeve 41, and the other end is fixedly connected to the other end of the airbag 20 in the axial direction of the first air tube 30. The structure of the sleeve and guide rod 42 is relatively simple and easy to assemble, thus reducing the overall manufacturing cost of the guide component 40. Simultaneously, the sliding pair between the sleeve and the guide rod 42 ensures high motion guidance accuracy of the guide component 40, strictly limiting the telescopic movement trajectory of the equipment, thereby ensuring the coaxiality of the axial movement and effectively preventing problems such as offset, skewness, and jamming during reciprocating motion. This effectively improves the regularity and stability of the overall movement.

[0034] According to some embodiments of the present invention, such as Figure 1 As shown, the guide member 40 also includes an elastic reset member 43, which is sleeved on the radially outer side of the guide rod 42 and connected between the guide sleeve 41 and the other end of the airbag 20. Specifically, the elastic reset member 43 allows the guide rod 42 to be pulled back into the guide sleeve 41 when the airbag 20 contracts, thereby synchronizing the contraction action of the guide rod 42 with that of the airbag, and effectively preventing structural damage to the guide member 40 caused by tension or compression.

[0035] According to some embodiments of the present invention, the elastic reset member 43 is a spring, which includes a first elastic segment, a second elastic segment and a third elastic segment arranged sequentially along the axial direction of the first air tube 30, wherein the rigidity of the first elastic segment is less than the rigidity of the second elastic segment and the rigidity of the second elastic segment is less than the rigidity of the third elastic segment.

[0036] It is understandable that the force required for the elastic deformation of the first elastic segment is less than that of the second elastic segment, and the force required for the elastic deformation of the second elastic segment is less than that of the third elastic segment. In other words, the first elastic segment is more prone to deformation than the second elastic segment, and the second elastic segment is also more prone to elastic deformation than the third elastic segment. This configuration allows the elastic reset member 43 of this embodiment to better adapt to the nonlinear law of the radial expansion of the airbag 20: that is, the expansion rate is faster in the early stage and gradually slows down in the later stage.

[0037] Specifically, in the initial stage of expansion, the low-stiffness first elastic segment can accommodate the rapid radial deformation of the airbag 20 in the early stage. This segment is primarily responsible for free expansion, effectively buffering the expansion impact and preventing localized stress concentration or tearing of the airbag 20 membrane material. As the expansion stroke increases, the spring pitch gradually decreases and the stiffness increases progressively, thus matching the slower radial deformation of the airbag 20 in the later stages. In the final stage of expansion, when the airbag 20 approaches its maximum rated outer diameter, the high-stiffness segment of the elastic reset member 43 provides effective constraint and limitation, assisting in controlling the maximum expanded outer diameter of the airbag 20.

[0038] Therefore, based on the above structure, this embodiment, by setting the elastic reset member 43 to include a first elastic segment, a second elastic segment and a third elastic segment arranged sequentially along the axial direction of the first air tube 30, can achieve dynamic adaptation to the full-stroke inflation process of the airbag 20, and at the same time, can also take into account the dual requirements of initial buffering and final positioning.

[0039] It should be noted that the guide rod 42 can be made of 304 stainless steel bellows, with a stainless steel axial guide sleeve added to the outside of the bellows. The spring is a variable pitch three-section variable stiffness alloy spring, made of 60Si2Mn high-strength alloy spring steel, which has the characteristics of high elasticity and high fatigue strength, and can withstand cyclic loads for a long time.

[0040] According to some embodiments of the present invention, such as Figure 1As shown, an air chamber is defined between the airbag 20 and the inner wall of the receiving cavity 11. The guide member 40 extends from both ends of the airbag 20 in the axial direction of the first air pipe 30. An air passage 44 is formed inside the guide member 40. One end of the air passage 44 is adapted to be connected to an inert gas source, and the other end is connected to the air chamber. It can be understood that in this embodiment, the guide member 40 serves as both a guide and an air inlet pipe. This reduces the number of parts used in the entire device, thereby reducing the production cost of the entire system. On the other hand, it also reduces leakage points, thereby improving the sealing performance of the entire system. The air chamber and the inert gas filling the air chamber allow the flexible airbag 20 to complete the gas storage without contacting the irregular inner wall of the salt cave. This avoids the mechanical wear of the membrane material by the sharp edges of the cave wall, thereby improving the safety and service life of the airbag 20. At the same time, it also eliminates the need for costly grinding or leveling of the inner wall of old salt caves in the gas storage system 100, thereby reducing the production cost of the entire gas storage system 100.

[0041] Optional, such as Figure 1 As shown, the gas storage system 100 also includes an inert gas distribution interface, which is connected to one end of the gas passage 44 and adopts a quick-connect flange joint. Its internal valve core is equipped with a pressure linkage regulating valve, which can realize automatic pressure replenishment / depressurization of inert gas according to the gas pressure data fed back by the monitoring unit.

[0042] The inert gas distribution interface includes an inert gas input terminal 45 and an inert gas output terminal 46. The inert gas input terminal 45 is connected to the ground inert gas storage and distribution system and is used to fill the gas chamber with inert gas to form an inert gas pressure barrier. The inert gas output terminal 46 is used to depressurize and replace the inert gas in the gas chamber. When the hydrogen concentration in the gas chamber exceeds the standard, the polluted gas can be discharged through the output terminal and the inert gas can be refilled.

[0043] It should be noted that the end of the guide sleeve away from the guide rod 42 is rigidly connected to the inert gas input end 45 and the inert gas output end 46 in a sealed manner.

[0044] According to some embodiments of the present invention, such as Figure 1 As shown, the gas storage system 100 also includes a hydrogen concentration sensor 50, which is located inside the gas chamber and used to detect the concentration of hydrogen gas inside the chamber. This allows for timely detection of leaks in the gas bladder 20, quickly triggering a leak investigation process. This enables personnel to work with the hydrogen concentration sensor 50 to locate the leak and complete repairs, effectively ensuring the airtightness and safe operation of the gas storage system 100.

[0045] It should be noted that the hydrogen concentration sensor 50 is mainly deployed in the gas cavity and at critical leakage points such as cracks in the surrounding rock.

[0046] According to some embodiments of the present invention, such as Figure 1 As shown, the gas storage system 100 also includes a first barometer 60, which is located inside the gas chamber and used to detect the gas pressure inside the gas chamber. Specifically, the first barometer 60 is mainly used to monitor the gas pressure of the inert gas in real time. This allows the control system to have inert gas adjustment reference data, and then it is convenient to adjust the amount of inert gas filling and releasing based on this data and the hydrogen pressure inside the gasbag 20, so that the gas pressure in the gas chamber is consistently slightly higher than the hydrogen pressure inside the gasbag 20, thereby forming a stable pressure barrier to effectively suppress hydrogen permeation and leakage.

[0047] According to some embodiments of the present invention, the guide 40 is a metal part, and the inner wall of the air passage 44 is provided with an anti-corrosion layer, which is made of polytetrafluoroethylene. In this way, the structural strength of the guide 40 is guaranteed, and it also has good corrosion resistance, thereby effectively improving the service life of the entire guide 40.

[0048] According to some embodiments of the present invention, such as Figures 1-2 As shown, along the thickness of the airbag 20 from the inside out, the airbag 20 includes a sealing layer 21, a pressure-bearing layer 22, a transition layer 23, and a protective layer 24. The sealing layer 21 is a composite fluorine-based nano-intercalated composite material, the pressure-bearing layer 22 is a ceramic matrix composite material, the ceramic matrix composite material includes a three-dimensional orthogonally woven fiber preform and a ceramic composite matrix filled in the pores of the preform, the transition layer 23 is a graphene-modified polyurethane nanocomposite material, and the protective layer 24 is a polyimide-polytetrafluoroethylene polymer composite material.

[0049] The inner sealing layer 21 is made of a composite fluorine-based nano-intercalated composite material, which can construct a dense and tortuous hydrogen barrier channel, significantly reducing the hydrogen permeation rate and thus achieving an ultra-low hydrogen permeation effect. At the same time, due to the material's excellent resistance to hydrogen embrittlement and salt brine corrosion, it can ensure that the material will not embrittle and fail during long-term storage of high-pressure hydrogen, thus enabling the airbag 20 to be adapted to the corrosive environment of underground salt caverns containing brine.

[0050] The ceramic matrix composite material of the three-dimensional orthogonal woven fiber preform has a strong structural load-bearing capacity and can stably withstand high-pressure working loads in the range of 20MPa to 35MPa. The material also has outstanding resistance to creep and fatigue. Therefore, by using the ceramic matrix composite material as the pressure-bearing layer 22, the deformation rate of the airbag 20 during repeated hydrogen charging and discharging cycles can be kept extremely low. This ensures that the airbag 20 will not undergo permanent deformation under long-term high-pressure conditions, thus guaranteeing the long-term stability of the volume and differential pressure control accuracy of the airbag 20.

[0051] The interlayer peel strength of the graphene-modified polyurethane nanocomposite material is not less than 25 MPa. That is, the graphene-modified polyurethane nanocomposite material is used as a transition layer 23 between the protective layer 24 and the pressure-bearing layer 22, which can firmly bond the multi-layer composite interface. This can effectively prevent the airbag 20 from delamination and debonding defects during long-term high and low pressure cycle service. At the same time, since the graphene-modified polyurethane nanocomposite material also has the function of blocking the hydrogen permeation bypass formed by the interlayer gap, it can further improve the overall airtight barrier effect.

[0052] The polyimide-polytetrafluoroethylene (PI / PTFE) composite material has the properties of antistatic, salt spray corrosion resistance, and hydrophobic and non-stick. Therefore, using it as a protective layer 24 can effectively isolate the internal pressure-bearing and sealing structure from dust, brine and corrosive media in the underground salt cave environment, effectively avoid the risk of hydrogen explosion caused by static electricity accumulation, and thus greatly improve the service life and operational safety of the airbag 20 under harsh underground working conditions.

[0053] Optionally, the material composition (parts by weight) of the sealing layer 21 includes: 70 parts of perfluoroether rubber (FFKM), 30 parts of hydrogenated nitrile butadiene rubber (HNBR), 8 parts of organic montmorillonite (OMMT), 2 parts of graphene quantum dots (GQDs), 1.5 parts of low molecular weight perfluoroether crosslinking agent, and 0.5 parts of antioxidant.

[0054] The preparation process of sealing layer 21 is as follows: FFKM and HNBR are added to a twin-screw extruder and melt-blended at 160℃~180℃; OMMT and GQDs are added and dispersed at high speed for 30 minutes to form a nano-intercalation blend; and sealing layer 21 substrate with a thickness of 2mm~3mm is prepared by vacuum molding.

[0055] The material composition of the pressure-bearing layer 22 includes: the reinforcing skeleton is made of T700 carbon fiber, basalt fiber and aramid 1414 in a three-dimensional orthogonal weaving in a mass ratio of 4:3:3; the impregnation slurry is 15 parts of nano SiC ceramic particles (particle size 50nm~100nm), 5 parts of boron fiber and 80 parts of water-based phenolic resin.

[0056] The preparation process of the pressure-bearing layer 22 is as follows: First, the fiber surface is modified by plasma etching and silane coupling agent; then, the three-dimensional braided skeleton is placed in a vacuum pressure impregnation equipment, impregnated with ceramic slurry at 120℃ and 0.8MPa, kept at temperature and pressure for 60 minutes, and after curing, a high-strength pressure-bearing skeleton with a thickness of 4mm~5mm is formed.

[0057] The material composition (parts by mass) of the transition layer 23 includes: 65 parts of thermoplastic polyurethane (TPU), 30 parts of polyimide (PI), 4 parts of amino-modified graphene (NH2-GNs), and 1 part of epoxy functional group coupling agent.

[0058] The preparation process of the transition layer 23 is as follows: using an in-situ polymerization grafting process, TPU and PI are melt-blended, amino-modified graphene is added, and the reaction is carried out at 190℃~210℃ for 30 minutes to prepare a gradient adhesive film with a thickness of 0.5mm~1mm, thereby achieving modulus transition and strong bonding between the sealing layer 21 and the pressure-bearing layer 22.

[0059] The material composition (parts by mass) of the protective layer 24 includes: 50 parts of polyimide (PI), 45 parts of polytetrafluoroethylene (PTFE), 3 parts of nano-conductive carbon black, and 2 parts of nano-TiO2.

[0060] The preparation process of the protective layer 24 is as follows: after the mixture is dispersed at high speed, a protective coating with a thickness of 1.5mm to 2mm is formed on the outside of the pressure-bearing layer 22 by spraying-thermal curing process; the surface of the coating is modified by plasma hydrophobicity to generate micron-level bump texture.

[0061] It should be noted that the airbag 20 uses a four-layer functional integrated composite membrane material with a total thickness of 8mm~12mm.

[0062] According to some embodiments of the present invention, such as Figures 1-3 As shown, the gas storage system 100 also includes a fiber Bragg grating sensor 70, which is located between the pressure-bearing layer 22 and the transition layer 23. The sensor is used to detect strain changes, temperature changes, and interface debonding damage at the interlayer interface. Specifically, the fiber optic sensing neural network is embedded in the membrane layer of the airbag 20 to achieve continuous monitoring of the airbag's strain, pressure, temperature, damage, and leakage. The fiber Bragg grating sensor 70 has a fast response speed, is inherently safe, and can precisely control the maximum expansion diameter of the airbag 20, providing real-time early warning of abnormal operating conditions. This significantly improves the intelligence level and operational safety of the device.

[0063] Optionally, the fiber Bragg grating sensor 70 includes: axial optical fiber and circumferential optical fiber. In this embodiment, 15 to 20 axial optical fibers are evenly arranged along the axial direction of the airbag 20 to monitor axial expansion and length changes; the circumferential optical fibers are arranged in a ring along the radial direction of the airbag 20 with a spacing of 70 to 80 cm to monitor radial expansion and outer diameter changes.

[0064] The following describes a molding process for the airbag 20 based on its structure: Step 1: First, the inner sealing layer 21, the interface transition layer 23, and the outer protective layer 24 are pre-formed into films, and the middle pressure-bearing layer 22 is 3D woven and ceramic impregnated and cured. Step 2: A three-dimensional orthogonal fiber neural network is laid out on the surface of the pressure-bearing layer 22 and fixed in a dotted manner with adhesive in the interface transition layer 23; Step 3: Coaxially and precisely stack the four membrane layers in the order of “sealing layer 21 → pressure-bearing layer 22 → transition layer 23 → protective layer 24”, without misalignment or wrinkles; Step 4: Place the above-layered membrane into a special mold, evacuate to -0.095MPa, heat to 180℃~220℃, pressurize to 15MPa~20MPa, keep warm and pressurize for 30min, the interface layer melts and crosslinks in situ, and the four layers of materials are fused into an integrated structure to obtain the pretreated capsule. Step 5: The pretreated bladder is naturally cooled to room temperature, and then subjected to low-temperature plasma surface modification to improve the antistatic properties of the outer layer. Finally, the finished flexible air storage bladder 20 is obtained by trimming the edges.

[0065] According to some embodiments of the present invention, the gas storage system 100 further includes a second barometer 80, which is disposed inside the gas bladder 20 and is used to detect the pressure of hydrogen gas inside the gas bladder 20. On the one hand, it can provide data for the pressure control of hydrogen injection and hydrogen collection, facilitating the linkage adjustment of the hydrogen filling and discharging volume of the gas bladder 20 and the inert gas filling and discharging volume of the gas chamber, so as to stably maintain the pressure difference between the gas bladder 20 and the gas chamber within a preset difference range; on the other hand, it can also promptly identify whether the gas bladder 20 is leaking by real-time monitoring of the internal pressure change of the gas during gas storage, thereby quickly triggering the leak investigation process, cooperating with the hydrogen concentration sensor 50 to locate the leak point and complete the repair, thus effectively ensuring the airtightness and safe use of the gas storage system 100.

[0066] According to the second aspect of the present invention, a gas storage method is used for a gas storage system 100 according to the first aspect, such as Figure 4 As shown, the method includes: Step S1: Obtain the three-dimensional morphological data of the cavity 11 and place the airbag 20 into the cavity 11 at a predetermined depth.

[0067] Specifically, sonar cavity exploration technology is used to obtain three-dimensional morphological data of the existing salt cavern cavity to determine the travel range of the combined support structure. Then, the airbag 20 is folded along the axis and evacuated, and then lowered to the predetermined depth of the salt cavern through the well barrel 12.

[0068] Step S2: Seal the opening of the receiving cavity 11 and control the gas storage system 100 to input hydrogen gas at a first preset pressure value into the airbag 20 so that the airbag 20 is in the deployed state. Specifically, the wellhead and surface area are sealed by using oil well cement-based sealing material, which is poured into the annular gap between the wellbore 12, the first gas pipe 30, and the guide component 40. The thickness of the sealing layer 21 is not less than 10cm. After pouring, it is cured for 24 hours until the strength of the sealing material reaches the standard, so as to achieve a complete seal of the wellhead and the surface and prevent gas from leaking from the wellhead gap.

[0069] Then, the inert gas output terminal 46 is opened, and hydrogen is injected into the airbag 20 through the first air tube 30. The inflation pressure is controlled at 0.5 MPa, so that the airbag 20 can expand adaptively in the irregular cavity of the salt cavern. At the same time, as the airbag 20 expands, the volume of the air cavity shrinks, and some of the air in the air cavity is discharged from the containment cavity 11. At this time, the initial setup of the device is completed.

[0070] Step S3: Control the gas storage system 100 to deliver inert gas at a second preset pressure value to the gas chamber, and confirm whether the pressure drop in the gas chamber is less than the first preset value. If yes, proceed to step S31; otherwise, proceed to step S32. Step S31: Control the gas storage system 100 to deliver inert gas into the gas chamber so that the pressure difference between the gas chamber and the airbag 20 is controlled within the first preset difference range. Step S32: Confirm the location of the leak, repair the leak, and then repeat step S3. Specifically, close the inert gas output terminal 46, and slowly inject inert gas into the gas chamber through the inert gas input terminal 45 and the gas passage 44. After the gas pressure in the gas chamber is increased to 0.3 MPa, close the inert gas input terminal 45, maintain the pressure for 30 minutes, and monitor the pressure change in real time through the first pressure gauge 60 in the gas chamber. If the pressure drop in the gas chamber during the pressure holding period is ≤0.01 MPa, the gas tightness in the gas chamber is deemed qualified, and subsequent operations can be carried out. If the pressure drop is >0.01 MPa, the gas tightness is deemed unqualified, and the leak point needs to be checked through the hydrogen concentration sensor 50 and the first pressure gauge 60. After repair, the gas tightness test is performed again until the test is qualified.

[0071] Once the test is passed, the inert gas inlet 45 is opened, and inert gas is continuously injected into the gas chamber through the gas passage 44 to replenish and replace the original inert gas used for the airtightness test in the gas chamber. At the same time, the residual air in the gas chamber is vented through the inert gas outlet 46. After venting, the inert gas outlet 46 is closed, and the pressure linkage regulating valve at the wellhead is activated. Based on the hydrogen pressure data inside the bladder fed back by the second barometer 80, the inert gas pressure in the gas chamber is adjusted in real time to ensure that the inert gas pressure in the gas chamber is always 0.2~0.5MPa higher than the hydrogen pressure inside the gas bladder 20. This creates a stable gas pressure leak-proof barrier outside the gas bladder 20, preventing hydrogen from leaking into the surrounding rock fissures.

[0072] It should be noted that the first barometer 60 is a high-precision, high-pressure resistant pressure monitoring element, which adopts a diffused silicon pressure sensor with a detection range of 0~20MPa and a detection accuracy of ±0.01MPa; the hydrogen concentration sensor 50 is a high-precision gas detection element, which adopts an electrochemical hydrogen concentration sensor 50 to accurately detect trace hydrogen leaks of 50ppm and below.

[0073] Step S4: Control the gas storage system 100 to input or output hydrogen into the gas bag 20, and to output or input inert gas into the gas chamber, so as to continuously control the pressure difference within the first pre-error value range.

[0074] Specifically, during hydrogen injection, hydrogen is injected uniformly into the gas bladder 20 through the hydrogen inlet 31, with the injection rate controlled within the designed rated flow range. During hydrogen injection, the pressure-linked regulating valve dynamically adjusts the gas pressure in the gas chamber in real time according to the hydrogen pressure in the gas bladder 20, continuously maintaining a stable pressure difference of 0.2~0.5MPa. The gas bladder 20 adapts to axial elongation and radial expansion as hydrogen is injected, maintaining a gap of 30~100cm with the gas chamber. During hydrogen extraction, hydrogen is output uniformly through the hydrogen outlet 32 ​​according to the hydrogen demand. During hydrogen extraction, the gas bladder 20 adapts to axial contraction and radial retraction, and the guide member 40 expands and contracts synchronously with the deformation of the gas bladder 20. The pressure-linked regulating valve synchronously reduces the inert gas pressure in the gas chamber, always maintaining a stable pressure difference and ensuring that the active gas pressure leak-proof barrier does not fail.

[0075] It should be noted that during the hydrogen injection and extraction processes, the monitoring unit monitors data such as the radial expansion of the capsule, axial expansion and contraction, local stress and strain, operating temperature, hydrogen permeation leakage, hydrogen concentration in the gas chamber, and internal and external pressure difference in real time, and transmits this data to the ground monitoring terminal. When the hydrogen concentration in the gas chamber exceeds 50 ppm, or the pressure difference between the capsule and the gas chamber exceeds ±0.6 MPa, the system automatically activates the pressure regulating valve to replenish inert gas. If the concentration continues to exceed the standard or the pressure difference is abnormal, an emergency alarm is triggered.

[0076] According to the gas storage method of the present invention, hydrogen storage can be achieved by simply modifying the salt cavern, and at the same time, the safety and reliability of the hydrogen storage process can be effectively guaranteed.

[0077] In the description of this invention, it should 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," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0079] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0081] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A gas storage system (100), characterized in that, include: Gas storage tank (10), the gas storage tank (10) having a receiving cavity (11); An airbag (20) is disposed within the receiving cavity (11) and is adapted to store hydrogen. The first trachea (30) has one end adapted to be connected to an external air source and the other end connected to the air bag (20). The size of the air bag (20) is adjustable in the axial direction of the first trachea (30). A guide (40) extends along the axial direction of the first air tube (30), at least a portion of the guide (40) is arranged inside the airbag (20), and both ends of the guide (40) are respectively connected to both ends of the airbag (20) in the axial direction of the first air tube (30), and the guide (40) is telescopic along the axial direction of the first air tube (30).

2. The gas storage system (100) according to claim 1, characterized in that, The guide member (40) includes a guide sleeve (41) and a guide rod (42). The guide sleeve (41) is fixedly connected to one end of the airbag (20) in the axial direction of the first air tube (30). The guide rod (42) extends along the axial direction of the first air tube (30). One end of the guide rod (42) is slidably fitted inside the guide sleeve (41), and the other end is fixedly connected to the other end of the airbag (20) in the axial direction of the first air tube (30).

3. The gas storage system (100) according to claim 2, characterized in that, The guide (40) further includes an elastic reset member (43), which is sleeved on the radially outer side of the guide rod (42) and connected between the guide sleeve (41) and the other end of the airbag (20).

4. The gas storage system (100) according to claim 3, characterized in that, The elastic reset member (43) is a spring, which includes a first elastic segment, a second elastic segment and a third elastic segment arranged sequentially along the axial direction of the first air pipe (30), wherein the rigidity of the first elastic segment is less than the rigidity of the second elastic segment and the rigidity of the second elastic segment is less than the rigidity of the third elastic segment.

5. The gas storage system (100) according to claim 1, characterized in that, An air cavity is defined between the airbag (20) and the inner wall of the receiving cavity (11). The guide (40) extends out of the airbag (20) at both ends in the axial direction of the first air tube (30). An air passage (44) is formed in the guide (40). One end of the air passage (44) is adapted to be connected to an inert gas source, and the other end is connected to the air cavity.

6. The gas storage system (100) according to claim 5, characterized in that, Also includes: A hydrogen concentration sensor (50) is disposed in the gas chamber and is used to detect the concentration of hydrogen in the gas chamber; And / or, a first barometer (60), which is located in the air chamber and is used to detect the air pressure in the air chamber.

7. The gas storage system (100) according to claim 1, characterized in that, Along the thickness of the airbag (20) from the inside out, the airbag (20) includes a sealing layer (21), a pressure-bearing layer (22), a transition layer (23), and a protective layer (24). The sealing layer (21) is a composite fluorine-based nano-intercalated composite material. The pressure-bearing layer (22) is a ceramic matrix composite material. The ceramic matrix composite material includes a three-dimensional orthogonally woven fiber preform and a ceramic composite matrix filled in the pores of the preform. The transition layer (23) is a graphene-modified polyurethane nanocomposite material. The protective layer (24) is a polyimide-polytetrafluoroethylene polymer composite material.

8. The gas storage system (100) according to claim 7, characterized in that, Also includes: A fiber Bragg grating sensor (70) is disposed between the pressure-bearing layer (22) and the transition layer (23) to detect strain changes, temperature changes and interface debonding damage at the interlayer interface.

9. The gas storage system (100) according to claim 1, characterized in that, Also includes: The second barometer (80) is located inside the airbag (20) and is used to detect the pressure of hydrogen gas inside the airbag (20).

10. A gas storage method for use in a gas storage system (100) according to any one of claims 1-9, characterized in that, The method includes: Step S1: Obtain three-dimensional morphological data of the cavity (11) and place the airbag (20) at a predetermined depth in the cavity (11); Step S2: Seal the opening of the receiving cavity (11) and control the gas storage system (100) to input hydrogen gas at a first preset pressure value into the airbag (20) so that the airbag (20) is in the deployed state; Step S3: Control the gas storage system (100) to deliver inert gas with a second preset pressure value to the gas chamber, and confirm whether the pressure drop of the gas chamber is less than the first preset value. If yes, execute step S31; otherwise, execute step S32. Step S31: Control the gas storage system (100) to deliver inert gas into the gas chamber so that the pressure difference between the pressure in the gas chamber and the pressure in the air bag (20) is controlled within a first preset difference range. Step S32: Confirm the location of the leak, repair the leak, and then repeat step S3. Step S4: Control the gas storage system (100) to input or output the hydrogen gas into the gas bag (20) and to output or input the inert gas into the gas chamber, so as to continuously control the pressure difference within the first preset difference range.

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