Construction method of adsorption type underground hydrogen storage library and method for preventing hydrogen leakage

Abstract

The invention discloses a construction method of an adsorption type underground hydrogen storage library and a method for preventing hydrogen leakage, and belongs to the technical field of energy storage, the construction method comprises the following steps: S1, preparing a modified material reduced graphene oxide; s2, carrying out modification treatment on the montmorillonite adsorbent; s3, constructing an underground rock salt dissolving cavity; s4, the underground dissolved cavity is filled with montmorillonite; and S5, carrying out temperature, pressure and flow monitoring on the hydrogen storage library. The modified montmorillonite loaded with reduced graphene oxide is used for filling a stratum to establish a hydrogen storage library, so that the hydrogen storage performance is greatly improved, the storage safety of hydrogen is improved, meanwhile, hydrogen injection and production are performed through pressurization and depressurization operation of an injection and production well, the huff and puff efficiency of hydrogen is improved, the economic cost of the hydrogen is reduced, and the method is suitable for popularization and application. And the economical efficiency of the hydrogen storage bank is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and particularly relates to a method for constructing an underground hydrogen storage reservoir by using the hydrogen adsorption capacity of montmorillonite modified with reduced graphene oxide to load hydrogen. Background Art

[0002] As an important part of the energy system, hydrogen energy shows great application potential in many fields. The underground hydrogen storage reservoir is an important infrastructure, which can store and distribute hydrogen energy well.

[0003] At present, the underground hydrogen storage reservoirs globally mainly include types such as depleted oil and gas reservoirs transformed into hydrogen storage reservoirs, salt cavern hydrogen storage reservoirs, aquifer hydrogen storage reservoirs, and liquefied hydrogen underground hydrogen storage reservoirs. Among them, traditional underground hydrogen storage reservoirs mostly utilize geological structures such as depleted oil and gas reservoirs or salt caverns. However, such hydrogen storage reservoirs have many problems: First, the hydrogen storage capacity is limited by geological conditions, making it difficult to meet the growing hydrogen demand, and there is also a relatively high risk of hydrogen leakage; second, the transformation of depleted oil and gas reservoirs and the exploitation of salt caverns require a large amount of engineering costs and time, resulting in high construction costs; third, the geological conditions of some underground hydrogen storage reservoirs are complex, with potential safety hazards such as leakage and collapse. In addition, since hydrogen is an inflammable and explosive gas, there are also certain safety risks during the hydrogen storage and gas production processes.

[0004] In recent years, the adsorption hydrogen storage technology has received more and more attention. In the past, the main problems of adsorption hydrogen storage reservoirs were low hydrogen storage density, dependence on low temperature or high pressure conditions, high material costs, and insufficient cycle stability, resulting in limited energy efficiency and poor economy in practical applications. Montmorillonite, as a natural mineral with a high specific surface area and strong adsorption capacity, is considered a promising adsorbent. Using the strong adsorption capacity of montmorillonite to build an underground hydrogen storage reservoir is expected to overcome the deficiencies of existing underground hydrogen storage methods, improve the hydrogen storage efficiency and safety, reduce the hydrogen storage cost, and promote the large-scale application of hydrogen energy. Summary of the Invention

[0005] The present invention proposes to use montmorillonite with a high specific surface area and strong adsorption capacity after sintering modification treatment to construct an underground hydrogen storage reservoir, so as to improve the hydrogen storage efficiency and economy.

[0006] The present invention is realized through the following technical solutions:

[0007] A method for constructing an adsorption-type underground hydrogen storage reservoir, comprising the following steps:

[0008] S1: Preparation of the modified material reduced graphene oxide,

[0009] S2: Modification treatment of the montmorillonite adsorbent,

[0010] S3: Construction of an underground rock salt cavity,

[0011] S4: Fill montmorillonite into the underground solution cavity.

[0012] S5: Monitor the temperature, pressure and flow rate of the hydrogen storage reservoir.

[0013] Furthermore, in step S1, the modified material reduced graphene oxide has excellent adsorption performance for hydrogen due to its unique atomic structure. First, each carbon atom in reduced graphene oxide is a surface atom, which can provide the largest surface area per unit volume, so it has a very large specific surface area, providing sufficient adsorption sites for hydrogen molecules. At the same time, its carbon atoms are arranged in a hexagonal honeycomb structure, forming a large π-bond conjugated system. There is a certain degree of overlap and interaction between the electron cloud structure of hydrogen and the π-electron cloud of graphene, thus generating π-π interaction, enabling hydrogen molecules to be adsorbed on the surface or between layers of graphene. And during the preparation process of graphene, some vacancies, edge defects, etc. will inevitably be generated, and these defect sites have high chemical activity and can react with certain components in hydrogen to form chemical bonds, thus realizing gas adsorption.

[0014] Furthermore, in step S2, montmorillonite has low cost and good stability, with a unique two-dimensional layered nanostructure and cation exchange characteristics. After modification, montmorillonite has stronger adsorption and chemical activity and can be used as an excellent porous carrier material. And montmorillonite loaded with reduced graphene oxide has greatly improved mechanical properties, adsorption properties and thermal stability, and can be well used as an adsorption material for hydrogen storage reservoirs.

[0015] Furthermore, in step S3, for salt cavern type underground hydrogen storage reservoirs, the "solution mining to create cavity" method is often used for construction. A salt cavern is a geological structure artificially formed by injecting water into a salt rock well. Impermeable salt rock deposits are most suitable for constructing stable and dense salt caverns. At the same time, salt caverns have a high injection and production rate, a short injection and production cycle, and a large gas storage capacity. Their high-salt environment can effectively inhibit underground microbial activities and prevent hydrogen pollution, forming a more stable and safe hydrogen storage environment. Their salt layer has low porosity, low permeability and good ductility, which can effectively prevent hydrogen leakage and prevent the formation of cracks. And compared with other rock masses, salt rock has excellent mechanical properties such as good thermal conductivity, small permeability, low porosity, strong plastic deformation ability and strong self-damage recovery ability, making it have an irreplaceable and prominent advantage in the safe and airtight storage of energy.

[0016] Furthermore, in step S4, filling the modified montmorillonite adsorption material into the underground solution cavity, the montmorillonite adsorption material not only plays the role of adsorbing hydrogen, but also can play a good supporting role for the underground solution cavity due to the mechanical properties of its solid particles.

[0017] Furthermore, in step 5, a monitoring tool is lowered into the hydrogen storage reservoir to monitor the temperature, pressure, and flow rate of the hydrogen storage reservoir. By monitoring the temperature, pressure, gas flow rate data of the hydrogen storage reservoir and their changes, the hydrogen storage performance of the established hydrogen storage reservoir can be reflected, and then the gas injection-production balance of the hydrogen storage reservoir can be controlled.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] 1) In the present invention, montmorillonite itself has a large specific surface area and a layered structure, which can provide physical adsorption sites. After loading reduced graphene oxide, the specific surface area and porosity of the material are further increased, thus greatly enhancing the adsorption capacity for hydrogen, and further increasing the hydrogen storage capacity of the hydrogen storage reservoir.

[0020] 2) In the present invention, montmorillonite has a certain gas barrier ability, and its layered structure can prevent the rapid diffusion of gas molecules. When reduced graphene oxide is loaded, this barrier performance is further enhanced. The graphene oxide sheets can fill some tiny voids between the montmorillonite layers to form a more dense barrier. Due to its good gas barrier property, it can effectively reduce gas leakage and ensure the effective storage of gas in the underground hydrogen storage reservoir for a long time.

[0021] 3) In the present invention, montmorillonite is a natural mineral material, which is rich in resources and can be recycled to a certain extent. And the process of loading and reducing graphene oxide adopts a green and environmentally friendly process, so using this composite material to construct an underground hydrogen storage reservoir is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0023] Figure 1 is the technical roadmap of the method of the present invention.

[0024] Figure 2 is the schematic diagram of the montmorillonite hydrogen storage reservoir of the present invention.

[0025] Figure 3 is the adsorption amount curve diagram of montmorillonite of the present invention.

[0026] Figure 4 is the adsorption volume curve diagram of montmorillonite of the present invention.

[0027] Figure 5 is the schematic diagram of salt cavern construction in the positive circulation stage of the present invention.

[0028] Figure 6 This is a schematic diagram of the construction of a salt cavern in the reverse circulation stage of the present invention. Detailed implementation manners

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0030] A method for constructing an adsorption-type underground hydrogen storage cavern, as Figure 1 shown, includes the following steps:

[0031] S1: Preparation of modified material reduced graphene oxide,

[0032] S2: Modified treatment of montmorillonite adsorbent,

[0033] S3: Construction of an underground rock salt cavity,

[0034] S4: Filling montmorillonite into the underground cavity,

[0035] S5: Monitoring the temperature, pressure, and flow rate of the hydrogen storage cavern. Specific embodiments:

[0037] The preparation of modified reduced graphene oxide in S1:

[0038] First, prepare the following materials: natural flake graphite, 93% concentrated sulfuric acid, 99% potassium permanganate, 30% hydrogen peroxide, 37% concentrated hydrochloric acid, 99.7% vitamin C, 99.9% nitrogen.

[0039] Preparation of graphene oxide (GO): Graphene oxide is prepared by the improved Hummers method; concentrated sulfuric acid, flake graphite, and potassium permanganate are added to the reaction kettle in a mass ratio of 100:1:3 in sequence, and after mixing evenly, the reaction is continued for stirring for 2 hours, and the temperature of the reaction solution is always kept below 10°C. The temperature is raised to 45°C and the reaction is carried out for 8 hours. The reaction solution is slowly introduced into water (the volume ratio of the reaction solution to water is 1:4), and continuous stirring is carried out. Hydrogen peroxide is added while it is hot until no obvious bubbles are generated. The material liquid is transferred into a ceramic membrane device for dialysis cleaning, and ultrasonic peeling is carried out by using a continuous ultrasonic device to obtain a GO dispersion liquid. The GO dispersion liquid is spray-dried to obtain a GO sample.

[0040] Preparation of reduced graphene oxide (rGO): Reduced graphene oxide is prepared by the thermal reduction method: The GO powder is placed in a tubular furnace, and under the protection of nitrogen, it is heated to 800°C at a rate of 10°C / min, kept warm for 30 minutes, and then naturally cooled to obtain an rGO sample.

[0041] The modification treatment of the montmorillonite adsorbent in S2:

[0042] Mechanically loading reduced graphene oxide: Mix montmorillonite and reduced graphene oxide at a mass ratio of 8:1, add an appropriate amount of dispersant and deionized water to prevent the agglomeration of reduced graphene oxide. Put the mixture into a ball mill, set the rotation speed at 200 - 500 rpm, and grind for 3 hours to uniformly load reduced graphene oxide onto montmorillonite.

[0043] Sintering into a porous composite material: Mix the montmorillonite material loaded with reduced graphene oxide with an appropriate amount of polyvinyl alcohol (binder), add an appropriate amount of water, and use a spherical mold to form a spherical green body. Put the green body into a high-temperature furnace and sinter at 800 °C for 6 hours. During the sintering process, physical and chemical interactions occur between montmorillonite and reduced graphene oxide to form a porous structure. After sintering, cool the sample in the furnace to room temperature, and then cut, grind, and polish it to obtain a composite material with the required size and surface quality.

[0044] Testing the adsorption performance of the montmorillonite in S2:

[0045] Use a fully automatic specific surface area and porosity analyzer (BET) to test the adsorption performance of the sintered montmorillonite adsorbent material. Take about 0.3 g of the adsorption material, dry it for 48 hours to remove volatile gases and moisture in the sample. Conduct N2 adsorption and desorption experiments with liquid nitrogen, with a degassing duration of 6 hours and a degassing temperature of 150 °C to obtain data such as specific surface area and adsorption capacity.

[0046] The test results are as Figure 3 、 Figure 4 shown that the adsorption capacity of the modified montmorillonite adsorbent material reaches 1500 cm 3 / g, and the adsorption volume is 6.7 cm 3 / g, indicating that it has a large specific surface area and is suitable as an adsorption material for underground hydrogen storage caverns.

[0047] The construction of the underground rock salt cavity in S3:

[0048] Adopt the "solution mining to create a cavity" method to construct the underground rock salt cavity. The specific steps are as follows:

[0049] Positive circulation stage: Inject fresh water into the salt layer through the wellbore at a speed of 3 - 5 cubic meters per hour. After the fresh water contacts the salt layer, the salt begins to dissolve to form brine, and a cavity gradually forms at the bottom of the salt layer; Reverse circulation stage: Turn on the pump of the reverse circulation pipeline to pump out the brine that has formed in the cavity; Alternating circulation stage: Alternate between positive circulation and reverse circulation. The scale of the salt cavern cavity continues to expand. As the cavity expands, gradually increase the fresh water injection speed and the brine discharge speed; Finally, complete the construction of the underground cavity.

[0050] In step S4, the modified montmorillonite is filled into the underground solution cavity:

[0051] The montmorillonite particles loaded with reduced graphene oxide are filled into the underground solution cavity by the dry filling method. The montmorillonite particles are transported along the wellbore to the underground solution cavity through a pumping device, and a stable transportation speed is maintained to ensure uniform filling of the particles. After the filling is completed, the montmorillonite adsorption material not only plays a role in adsorbing hydrogen, but also provides support for the underground solution cavity, enhancing the structural stability.

[0052] In step S5, the temperature, pressure and flow rate of the hydrogen storage reservoir are monitored:

[0053] The fiber optic type permanent temperature, pressure and flow rate monitoring system is used to monitor the hydrogen storage reservoir in real time. The system includes: downhole fiber optic pressure and temperature sensors, flow rate monitors, downhole signal transmission optical cables, wellhead signal modems, and display terminals. Monitoring steps: Install temperature and pressure gauges and flow rate monitors at the inlet and outlet pipelines of the hydrogen storage reservoir, and transmit the real-time monitoring data to the surface terminal through optical fibers. By monitoring the temperature, pressure and gas flow rate data of the hydrogen storage reservoir, the injection and production gas balance of the hydrogen storage reservoir is controlled to ensure the safe operation of the hydrogen storage reservoir.

[0054] Regarding the operation and maintenance of the hydrogen storage reservoir in step S5:

[0055] Hydrogen injection and storage: Hydrogen is filled into the hydrogen storage reservoir, and the pressure in the hydrogen storage reservoir is controlled at 1 - 10 MPa and the temperature at 20 - 60 °C. The montmorillonite adsorption material loaded with reduced graphene oxide is used to adsorb and store hydrogen to ensure the efficient storage and safety protection of hydrogen.

[0056] Regular monitoring and maintenance: Regularly check the temperature, pressure and gas flow rate data of the hydrogen storage reservoir through the fiber optic monitoring system, and promptly discover and handle potential problems. Adjust the injection and production gas operations according to the monitoring data to ensure the long-term stable operation of the hydrogen storage reservoir.

[0057] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A construction method of an adsorption-type underground hydrogen storage reservoir, characterized in that It includes the following steps: S1. Preparation of modified material-reduced graphene oxide; S2. Modification treatment of montmorillonite adsorbent; S3. Construction of underground rock salt solution cavity; S4. Filling montmorillonite into the underground solution cavity; S5. Monitoring the temperature, pressure and flow rate of the hydrogen storage reservoir.

2. The construction method of an adsorption-type underground hydrogen storage reservoir according to claim 1, characterized in that, In step S1, using natural flake graphite, concentrated sulfuric acid, potassium permanganate, hydrogen peroxide, concentrated hydrochloric acid, vitamin C and nitrogen as raw materials, graphene oxide is prepared by the improved Hummers method; the graphene oxide powder is thermally reduced under nitrogen protection, heated to 800 °C and kept warm for 30 minutes to obtain reduced graphene oxide. The strong oxidant is one or more of potassium permanganate, concentrated sulfuric acid and sodium nitrate; the reducing agent is one or more of hydrazine hydrate, vitamin C and sodium borohydride.

3. The construction method of an adsorption-type underground hydrogen storage reservoir according to claim 2, wherein, The specific process parameters of the improved Hummers method are: the mass ratio of concentrated sulfuric acid, graphite and potassium permanganate in the reaction solution is 100:1:3, the reaction temperature is controlled below 10 °C and stirred for 2 hours, then heated to 45 °C and reacted for 8 hours, and finally the graphene oxide sample is obtained through dialysis cleaning and spray drying.

4. The construction method of an adsorption-type underground hydrogen storage library according to claim 1, characterized in that In step S2, montmorillonite and reduced graphene oxide are mixed at a mass ratio of 8:1, a dispersant and deionized water are added, and ground in a ball mill at a speed of 200 - 500 rpm for 3 hours; the mixture is mixed with a polyvinyl alcohol binder to form a green body, and sintered at 800 °C for 6 hours to form a porous composite material.

5. The construction method of an adsorption-type underground hydrogen storage library as described in claim 3, characterized in that, The specific surface area of the sintered montmorillonite adsorbent is 1500 cm 3 / g, and the adsorption volume is 6.7 cm 3 / g.

6. The construction method of an adsorption-type underground hydrogen storage reservoir according to claim 1, wherein In step S3, the specific operation steps for constructing an underground salt cavern solution cavity by the positive and negative circulation water-soluble cavity construction method include: in the positive circulation stage, fresh water is injected into the salt layer at a speed of 3 - 5 cubic meters per hour to dissolve the salt layer to form brine; in the negative circulation stage, the brine in the solution cavity is pumped out through the negative circulation pipeline; the positive and negative circulations are alternately carried out to gradually expand the scale of the solution cavity.

7. The construction method of an adsorption-type underground hydrogen storage reservoir according to claim 6, characterized in that During the construction of the solution cavity, the fresh water injection speed and the brine discharge speed are gradually increased according to the expansion degree of the solution cavity.

8. The construction method of an adsorption-type underground hydrogen storage reservoir according to claim 1, wherein In step S4, the modified montmorillonite particles are pumped into the underground solution cavity by the dry filling method, and a stable conveying speed is maintained to ensure uniform filling.

9. The construction method of an adsorption-type underground hydrogen storage library according to claim 1, characterized in that, In step S5, by deploying a fiber optic type permanent temperature, pressure and flow rate monitoring system in the gas storage reservoir, temperature, pressure and flow rate data are collected and transmitted to the ground terminal in real time through downhole fiber optic sensors, flow rate monitors and signal transmission devices.

10. The construction method of an adsorption-type underground hydrogen storage reservoir as described in claim 9, characterized in that, The fiber optic type monitoring system includes downhole fiber optic pressure and temperature sensors, flow rate monitors, signal modems and display terminals, and real-time data is transmitted to the ground terminal through optical cables.

11. A method for preventing hydrogen leakage from an adsorption-type underground hydrogen storage reservoir, characterized in that, The underground hydrogen storage reservoir constructed by the method described in any one of claims 1 - 10 is used for hydrogen storage, and it includes the following steps: filling hydrogen into the hydrogen storage reservoir, and controlling the pressure and temperature in the hydrogen storage reservoir; using the montmorillonite-based composite hydrogen storage material to adsorb and store hydrogen; regularly monitoring parameters such as the hydrogen concentration, pressure and temperature in the hydrogen storage reservoir, and timely discovering and handling leakage hazards.

12. The method for preventing hydrogen leakage from an adsorption-type underground hydrogen storage reservoir according to claim 11, wherein, The pressure in the hydrogen storage reservoir is controlled at 1 - 10 MPa, the temperature is controlled at 20 - 60 °C, and the regular monitoring frequency is once a day or once a week.

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