Based on water-CO 2 -Structure and method of geological carbon fixation and hydrogen production by spontaneous reaction of active minerals

Abstract

The present invention discloses a method based on water-CO 2 The invention relates to a geological carbon fixation and hydrogen production structure and method for spontaneous reaction of active minerals, belonging to the technical field of carbon fixation and hydrogen production. The method of the invention comprises the following steps: (1) carbon dioxide collection; (2) selecting a carbon fixation and hydrogen production site; (3) constructing a carbon fixation and hydrogen production space; (4) carbon dioxide mineralization and storage and synchronous hydrogen production; (5) hydrogen recovery. The method permanently mineralizes and stores carbon dioxide while using water-CO 2 The synchronous geological hydrogen production by active mineral reaction not only reduces the economic cost of geological storage of carbon dioxide, but also opens up a new path for in-situ geological hydrogen production, realizing green and low-carbon production of hydrogen energy. The present invention also provides a geological carbon fixation hydrogen production structure, which is designed and constructed with low storage cost and large-scale synchronous geological hydrogen production.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon fixation and hydrogen production, and in particular to a geological carbon fixation and hydrogen production structure and method based on the spontaneous reaction of water-CO2-active minerals. Background Art

[0002] With the rapid development of modern society, the demand for fossil energy is increasing, the emission of greenhouse gases such as carbon dioxide in the atmosphere has increased significantly, and global ecological and environmental problems such as rising temperatures and climate change are becoming increasingly severe. Carrying out carbon dioxide emission reduction has become an urgent need for the development of countries around the world. Carbon dioxide capture, utilization and storage (CCUS) technology can separate carbon dioxide from industrial processes, energy utilization or the atmosphere, and use it or inject it back into the formation, thereby achieving permanent carbon dioxide emission reduction. At the same time, it is also a key supplementary means for the existing energy system to transform to a low-carbon one, which helps to balance the needs of economic development and environmental protection.

[0003] Carbon dioxide geological storage is expected to permanently store up to trillions of tons of carbon dioxide in shallow or deep specific reservoirs. Carbon dioxide mineralization storage technology is to produce carbonate precipitated minerals through chemical reactions between carbon dioxide dissolved in formation water and formation rock minerals, and then mineralize and store it. Mineralization storage is the most permanent and safe storage mechanism in carbon dioxide geological storage. Carbon dioxide mineralization storage has the characteristics of low raw material prices, low energy consumption, spontaneous reactions, permanent carbon fixation and no leakage risk, and has broad application prospects.

[0004] Hydrogen energy has the advantages of high energy density, high calorific value and diversified sources. The current hydrogen production technology is still mainly based on fossil energy hydrogen production, and "grey hydrogen" produced from fossil fuels such as coal, oil and natural gas accounts for about 95%. Although this technical route is mature, a large amount of carbon dioxide will be emitted during the hydrogen production process, which is not the best choice from an environmental perspective. The technology of "blue hydrogen" made from natural gas through steam methane reforming or autothermal steam reforming and "green hydrogen" made from renewable energy is still under development and has high costs.

[0005] Traditional industrial hydrogen production methods require the preparation of reaction vessels, energy input such as electrolysis or catalysts, and therefore are relatively costly. Traditional deep reservoir carbon dioxide geological mineralization storage methods can store carbon dioxide in deep reservoirs and transform it into rocks such as carbonates through mineralization, but they do not consider the simultaneous geological hydrogen production in combination with the site advantages of mineralization storage. Summary of the invention

[0006] In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, a geological carbon fixation and hydrogen production structure is provided, which has a lower storage cost than the traditional industrial hydrogen production means and can produce hydrogen synchronously with the geological method, including a CO2 injection channel, a H2 recovery channel, a geological reaction ore layer and a closed structure;

[0007] The geological reaction ore layer includes active minerals that serve as both filling materials and reaction substrates; the outer layer of the geological reaction ore layer is sealed by a closed structure; the closed structure can block the diffusion of carbon dioxide and hydrogen from the inside to the outside;

[0008] The CO2 injection channel penetrates the closed structure and extends into the geological reaction stratum to inject the carbon dioxide and water required for the reaction; the hydrogen produced by the reaction escapes from the geological reaction stratum due to the density difference with the active minerals and is recovered through the H2 recovery channel that penetrates the closed structure;

[0009] Active minerals have the ability to fix carbon and produce hydrogen. Their components include metal oxides that react with carbon dioxide to form carbonates, and ferrous ions that react with water to produce hydrogen.

[0010] Preferably, the active ore includes at least one of kamatite, taeniaite, pyroxene, olivine, magnetite, chalcopyrite and basalt.

[0011] Active minerals containing ferrous ions such as taenite, taenite, pyroxene, olivine, magnetite, chalcopyrite, etc. in basalt and chalcopyrite slag can spontaneously react with water and carbon dioxide to produce hydrogen. This reaction does not require additional energy input or catalysts.

[0012] Preferably, according to the depth of the stratum for carbon fixation and hydrogen production, the geological carbon fixation and hydrogen production structure is divided into a shallow geological carbon fixation and hydrogen production structure and a deep geological carbon fixation and hydrogen production structure.

[0013] Further preferably, in the shallow geological carbon fixation and hydrogen production structure, the closed structure is an artificial closed layer; the geological reaction ore layer is an artificial sealing layer, including one of an abandoned open-pit mine and an abandoned underground mining tunnel.

[0014] Further preferably, in the deep geological carbon fixation and hydrogen production structure, after H2 escapes, it gathers under the barrier of the closed structure to form a hydrogen-enriched area, which is recovered by the H2 recovery channel 2; the closed structure is a natural closed cap layer; the geological reaction stratum is a natural mineralized sealing layer, including a natural saline layer, a depleted oil and gas reservoir, and a basalt stratum rich in natural fractures.

[0015] In the second aspect of the present invention, a geological carbon fixation and hydrogen production method capable of large-scale carbon fixation and hydrogen production and easy to control is provided, which adopts the geological carbon fixation and hydrogen production structure of the first aspect of the present invention, and performs geological carbon fixation and hydrogen production based on the spontaneous reaction of water-CO2-active minerals, comprising the following steps:

[0016] (1) Carbon dioxide collection:

[0017] Capturing carbon dioxide from industrial production activities;

[0018] (2) Select the location for carbon fixation and hydrogen production:

[0019] Through geological surveys and other means, areas suitable for geological carbon fixation and hydrogen production are selected as geological reaction strata, which are divided into shallow geological carbon fixation and hydrogen production sites and deep geological carbon fixation and hydrogen production sites according to the depth of the strata for carbon fixation and hydrogen production;

[0020] (3) Building space for carbon fixation and hydrogen production:

[0021] The geological reaction ore layer is sealed with a closed structure to seal carbon dioxide and prevent hydrogen leakage; the CO2 injection channel and the H2 recovery channel are connected to the geological reaction ore layer through the closed structure to construct a carbon fixation and hydrogen production space that can smoothly carry out carbon fixation and hydrogen production and subsequent product recovery; carbon dioxide and water are injected into the geological reaction ore layer through the CO2 injection channel;

[0022] (4) Carbon dioxide mineralization storage and simultaneous hydrogen production:

[0023] Carbon dioxide, water and active minerals are used to mineralize and store carbon dioxide and produce hydrogen simultaneously based on the spontaneous reaction of CO2-water-active minerals;

[0024] (5) Hydrogen recovery:

[0025] After the mineralization of carbon dioxide and the accumulation of hydrogen are completed, the hydrogen is stored in the rock pores in the geological reaction strata and the upper space of the reservoir. The hydrogen and other by-products are recovered through the H2 recovery channel.

[0026] Preferably, in step (2), the shallow geological carbon fixation and hydrogen production site is an artificial sealing layer, including abandoned open-pit mines and abandoned underground mining tunnels; the deep geological carbon fixation and hydrogen production site is a natural mineralized sealing layer, including natural saline water layers, depleted oil and gas reservoirs, and basalt formations rich in natural fractures.

[0027] Further preferably, when a shallow geological carbon fixation and hydrogen production site is used in step (2), in step (3), the construction process of the carbon fixation and hydrogen production space includes designing and laying an artificial sealed layer, grinding active ore and filling it into the artificial sealing layer, and injecting carbon dioxide and water.

[0028] The design of artificial sealing layer materials can refer to natural sealing caprocks. At present, abundant natural hydrogen reservoirs have been found in the Pyrenees Mountains in Spain and Bourakébougou in Mali. Their natural sealing caprocks are mainly dense shales and diabases. Active ores such as basalt, chalcopyrite pyrite slag, which exist in large quantities in nature, are ground and then filled into the sealing layer of shallow reservoirs. These active ores are not only filling materials for open-pit mines and underground tunnels, but also reaction substrates for carbon fixation and hydrogen production. Rock minerals with the ability to fix carbon and produce hydrogen include kamatite, nickel tungsten, pyroxene, olivine, magnetite, chalcopyrite pyrite, etc., and rocks include basalt, etc. The mass percentage of ferrous ions in basalt is about 15%. This solution can simultaneously solve the problem of insufficient filling materials such as gangue. Finally, a mixed fluid containing carbon dioxide and water is continuously injected into the bottom of the geological storage site through a high-pressure injection device to react with the rock.

[0029] Further preferably, when a deep geological carbon fixation and hydrogen production site is used in step (2), in step (3), the deep reservoir has a natural mineralized sealing layer and a natural closed cap layer, and carbon dioxide and water are injected by drilling or abandoning oil and gas wells.

[0030] Further preferably, when a shallow geological carbon fixation and hydrogen production site is used in step (2), in step (5), a pipeline is laid as an H2 recovery channel to recover hydrogen and by-products.

[0031] Further preferably, when a deep geological carbon fixation and hydrogen production site is used in step (2), in step (5), the hydrogen-enriched area is explored and the wellbore is used as an H2 recovery channel to recover the hydrogen.

[0032] Based on the above technical scheme, the inventive concept of the present invention is to utilize the spontaneous reaction of water-CO2-active minerals to carry out carbon dioxide mineralization and storage and synchronous hydrogen production. Carbon dioxide dissolves in water to form carbonic acid. Basalt, pyrite, pyrite, magnetite, olivine and other active minerals containing ferrous ions. The acidity of carbonic acid causes minerals such as kamanite, taenite, pyroxene, olivine, magnetite, pyrite and ferrous ions to dissolve and release ferrous ions. The released ferrous ions are adsorbed on the surface of the rock as electron donors for reducing water and producing hydrogen, and hydrogen is produced. This process does not require additional energy input and catalysts. After the rock reacts with carbon dioxide and water, magnesium, calcium, potassium, phosphorus and other nutrients will be released, and the by-products can be used as artificial soil improvement to increase the yield of crops.

[0033] The present invention is intended to utilize abandoned open-pit mines, abandoned underground mining tunnels, and natural geological spaces in deep reservoirs, combined with the characteristics of spontaneous reactions of water-CO2-active minerals that do not require additional energy input and catalysts, to greatly reduce the cost of hydrogen production. When the carbon fixation site is in shallow areas such as abandoned open-pit mines and abandoned underground mining tunnels, tailings, basalt, etc. can be used for carbon fixation and hydrogen production to solve the problem of insufficient backfill and filling materials; personnel and construction equipment can reach shallow areas to carry out construction operations such as gravel filling, laying closed layers, laying injection channels, laying recovery channels, and collecting calcium carbonate byproducts, so it has the advantages of low requirements for geological conditions and easy control. For natural geological spaces in deep reservoirs, such as natural saline layers, depleted oil and gas reservoirs, etc., it has a larger space and can achieve larger-scale carbon fixation and hydrogen production.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] The present invention provides a geological carbon fixation and hydrogen production structure, the design and construction of which has low requirements on geological conditions and is easy to control, and has the functions of low sealing cost and large-scale synchronous geological hydrogen production.

[0036] The present invention provides a method for geological carbon fixation and hydrogen production, which can permanently mineralize and seal carbon dioxide while simultaneously conducting geological hydrogen production using the water-CO2-active mineral reaction. This not only reduces the economic cost of geological storage of carbon dioxide, but also opens up a new path for in-situ geological hydrogen production, thereby achieving green and low-carbon production of hydrogen energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the geological carbon fixation and hydrogen production structure of an abandoned open-pit mine;

[0038] Figure 2 This is a schematic diagram of the geological carbon fixation and hydrogen production structure of underground tunnels;

[0039] Figure 3 This is a schematic diagram of the carbon fixation and hydrogen production structure in deep reservoir geology;

[0040] Figure 4 A flow chart of the geological carbon fixation and hydrogen production method;

[0041] Figure 5 The hydrogen production curve of basalt over time obtained for indoor experiments;

[0042] Figure 6 The hydrogen production curve of brass pyrite over time obtained for indoor experiments;

[0043] In the figure: 1. CO2 injection channel; 2. H2 recovery channel; 3. Artificial sealed layer; 4. Artificial storage layer; 5. Hydrogen enriched area; 6. Natural sealed cover layer; 7. Natural mineralized storage layer. DETAILED DESCRIPTION

[0044] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0045] Example 1

[0046] This embodiment provides a method for geological carbon fixation and hydrogen production, using Figure 1 The abandoned open-pit mine geological carbon fixation and hydrogen production structure shown in the figure is based on the spontaneous reaction of water-CO2-active minerals to carry out geological carbon fixation and hydrogen production. The process is as follows Figure 4 As shown, the steps are as follows:

[0047] (1) Carbon dioxide collection:

[0048] Capturing carbon dioxide from industrial production activities;

[0049] (2) Select the location for carbon fixation and hydrogen production:

[0050] Using abandoned open-pit mines as artificial storage layers4;

[0051] (3) Building space for carbon fixation and hydrogen production:

[0052] The artificial sealing layer 4 is filled with active rocks such as ground basalt, brass pyrite slag, etc., and is a place where water-CO2-active minerals spontaneously react to fix carbon and produce hydrogen; the artificial sealing layer 3 is used to seal the four sides of the artificial sealing layer 4 to isolate it from the surrounding environment, seal carbon dioxide and prevent hydrogen leakage; the CO2 injection channel 1 leads from the surface to the bottom of the active ore of the artificial sealing layer 4, so that carbon dioxide and water can fully react with the active ore; the H2 recovery channel 2 is located on both sides of the CO2 injection channel 1, connected to the top of the periphery of the artificial sealing layer 4, to facilitate the recovery of hydrogen; inject carbon dioxide and water;

[0053] (4) Carbon dioxide mineralization storage and simultaneous hydrogen production:

[0054] Carbon dioxide, water and active minerals are used to mineralize and store carbon dioxide and produce hydrogen simultaneously based on the spontaneous reaction of CO2-water-active minerals;

[0055] (5) Hydrogen recovery:

[0056] After the mineralization of carbon dioxide and the accumulation of hydrogen are completed, the hydrogen is stored in the rock pores in the geological reaction strata and the upper space of the reservoir, and pipelines are laid as H2 recovery channels to recover hydrogen and other by-products.

[0057] Example 2

[0058] This embodiment provides a method for geological carbon fixation and hydrogen production, using Figure 2 The underground tunnel geological carbon fixation and hydrogen production structure shown is based on the spontaneous reaction of water-CO2-active minerals to carry out geological carbon fixation and hydrogen production. The steps are as follows:

[0059] (1) Carbon dioxide collection:

[0060] Capturing carbon dioxide from industrial production activities;

[0061] (2) Select the location for carbon fixation and hydrogen production:

[0062] Using underground tunnels as artificial storage layer 4;

[0063] (3) Building space for carbon fixation and hydrogen production:

[0064] The artificial sealing layer 4 is filled with active rocks such as ground basalt, brass pyrite slag, etc., and is a place where water-CO2-active minerals spontaneously react to fix carbon and produce hydrogen; the artificial sealing layer 3 is used to seal the four sides of the artificial sealing layer 4 to isolate it from the surrounding environment, seal carbon dioxide and prevent hydrogen leakage; the CO2 injection channel 1 leads from the entrance of the underground tunnel to the bottom of the active ore of the artificial sealing layer 4, so that CO2 and water can fully react with the active ore; the H2 recovery channel 2 is located above the CO2 injection channel 1 and is connected to the top of the active ore of the artificial sealing layer 4 to facilitate the recovery of hydrogen; inject carbon dioxide and water;

[0065] (4) Carbon dioxide mineralization storage and simultaneous hydrogen production:

[0066] Carbon dioxide, water and active minerals are used to mineralize and store carbon dioxide and produce hydrogen simultaneously based on the spontaneous reaction of CO2-water-active minerals;

[0067] (5) Hydrogen recovery:

[0068] After the mineralization of carbon dioxide and the accumulation of hydrogen are completed, the hydrogen is stored in the rock pores in the geological reaction strata and the upper space of the reservoir, and pipelines are laid as H2 recovery channels to recover hydrogen and other by-products.

[0069] Example 3

[0070] This embodiment provides a method for geological carbon fixation and hydrogen production, using Figure 3 The deep reservoir geological carbon fixation and hydrogen production structure shown is based on the spontaneous reaction of water-CO2-active minerals to carry out geological carbon fixation and hydrogen production. The steps are as follows:

[0071] (1) Carbon dioxide collection:

[0072] Capturing carbon dioxide from industrial production activities;

[0073] (2) Select the location for carbon fixation and hydrogen production:

[0074] Using natural saline water layers, depleted oil and gas reservoirs or basalt formations rich in natural fractures as natural mineralized storage layers7;

[0075] (3) Building space for carbon fixation and hydrogen production:

[0076] The natural mineralized storage layer 7 contains active ores for storing carbon dioxide, and is a place where water-CO2-active minerals spontaneously react to fix carbon and produce hydrogen; the natural closed cap layer 6 is used to prevent carbon dioxide and hydrogen from leaking to other places under pressure; the CO2 injection channel 1 is a wellbore formed by drilling, leading to the bottom of the natural mineralized storage layer 7, and is used to inject carbon dioxide and water into the carbon fixation and hydrogen production area, and the H2 recovery channel 2 is a wellbore formed by drilling, located at the top of the carbon fixation and hydrogen production area, and is used to recover hydrogen; since the density of hydrogen is lower than that of most fluids, a hydrogen-enriched area 5 will be formed above the natural mineralized storage layer 7, and the design of the H2 recovery channel 2 to connect this area is conducive to hydrogen recovery;

[0077] (4) Carbon dioxide mineralization storage and simultaneous hydrogen production:

[0078] Carbon dioxide, water and active minerals are used to mineralize and store carbon dioxide and produce hydrogen simultaneously based on the spontaneous reaction of CO2-water-active minerals;

[0079] (5) Hydrogen recovery:

[0080] After the mineralization of carbon dioxide and the accumulation of hydrogen are completed, the hydrogen is stored in the rock pores in the geological reaction strata and the upper space of the reservoir. The hydrogen-enriched areas are explored and the hydrogen is recovered using wellbores.

[0081] Example 4

[0082] This example studies the effectiveness of the method of the present invention in mineralizing and storing carbon dioxide and producing hydrogen simultaneously under a simulated environment. The working principle of the present invention is represented by the chemical equation of spontaneous reaction of water-CO2-active minerals to generate hydrogen:

[0083] CO2+MgO / CaO=MgCO3 / CaCO3 (1)

[0084] 2FeO+H2O=H2+Fe2O3 (2)

[0085] Carbon dioxide reacts with calcium and magnesium ions in rocks to mineralize and fix carbon (reaction formula 1). Iron-rich rocks produce a large amount of hydrogen under the interaction of water-CO2-rock (reaction formula 2). Carbon dioxide dissolves in water to form carbonate acid. The acidity of carbonate acid causes minerals such as pyroxene, magnetite, and olivine containing ferrous ions to dissolve and release ferrous ions. The released ferrous ions are adsorbed on the surface of basalt and serve as electron donors for reducing water and producing hydrogen, thereby producing hydrogen.

[0086] Indoor experiments were used to study the effectiveness of spontaneous reactions of carbon dioxide, water, and basalt for mineralization and storage of carbon dioxide and simultaneous hydrogen production. In the experiment, 2g of rock sample was first broken up, then placed in a ball mill and evacuated, and then ball-milled in an anaerobic environment for 20 hours. Then, water (100mL) was added to the anaerobic glove box to extract the rock powder. The solution was then injected into small glass bottles (5mL each), and dry ice (CO2) was added for aeration and capping. After a certain reaction time, the hydrogen production was detected by gas chromatography. The curve of basalt hydrogen production changing with time was obtained through indoor experiments. Figure 5 As shown, the hydrogen production continued to increase in the first three days, and then stabilized after three days. It was also found that the water-CO2-basalt reaction produced hydrogen, but in the absence of carbon dioxide, the water-basalt reaction did not produce hydrogen. This shows that groundwater and basalt have been in a stable state after tens of thousands of years of coexistence, and hydrogen is only produced when carbon dioxide is additionally present, that is, during the storage process. Indoor experiments were used to study the effectiveness of spontaneous reactions of carbon dioxide, water, and chalcopyrite for carbon dioxide mineralization, storage, and synchronous hydrogen production. The experimental steps are the same as above. The curve of the change in hydrogen production of chalcopyrite over time was obtained using indoor experiments. As shown Figure 6 As shown, the hydrogen production continued to increase in the first 9 days, verifying the effectiveness of this method.

[0087] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for producing hydrogen by geological carbon fixation, characterized in that: The steps include: (1) Carbon dioxide collection: Capturing carbon dioxide from industrial production activities; (2) Selecting a site for carbon fixation and hydrogen production: Through geological survey, areas suitable for geological carbon fixation and hydrogen production are selected as geological reaction strata, which are divided into shallow geological carbon fixation and hydrogen production sites and deep geological carbon fixation and hydrogen production sites according to the depth of the strata for carbon fixation and hydrogen production; (3) Building space for carbon fixation and hydrogen production: The geological reaction ore layer is sealed with a closed structure to seal carbon dioxide and prevent hydrogen leakage; the CO2 injection channel and the H2 recovery channel are connected to the geological reaction ore layer through the closed structure to construct a carbon fixation and hydrogen production space that can smoothly carry out carbon fixation and hydrogen production and subsequent product recovery; carbon dioxide and water are injected into the geological reaction ore layer through the CO2 injection channel; (4) Carbon dioxide mineralization storage and simultaneous hydrogen production: Carbon dioxide, water and active minerals are used to mineralize and store carbon dioxide and produce hydrogen simultaneously based on the spontaneous reaction of CO2-water-active minerals; (5) Hydrogen recovery: After the mineralization of carbon dioxide and the accumulation of hydrogen are completed, hydrogen is stored in the rock pores in the geological reaction strata and the upper space of the reservoir. Hydrogen and other by-products are recovered through the H2 recovery channel. When a shallow geological carbon fixation and hydrogen production site is used in step (2), in step (3), the construction process of the carbon fixation and hydrogen production space includes designing and laying an artificial closed layer, grinding active ore to fill the artificial sealing layer, and injecting carbon dioxide and water; when a deep geological carbon fixation and hydrogen production site is used in step (2), in step (3), the deep reservoir has a natural mineralized sealing layer and a natural closed cap layer, and carbon dioxide and water are injected by drilling or abandoning oil and gas wells; The geological carbon fixation and hydrogen production adopts a geological carbon fixation and hydrogen production structure, which includes a CO2 injection channel (1), an H2 recovery channel (2), a geological reaction ore layer and a closed structure; the geological reaction ore layer includes an active mineral that serves as both a filling material and a reaction substrate; the outer layer of the geological reaction ore layer is closed by a closed structure; the closed structure can block the diffusion of carbon dioxide and hydrogen from the inside to the outside; the CO2 injection channel (1) penetrates the closed structure and extends into the geological reaction ore layer to inject carbon dioxide and water required for the reaction; the hydrogen generated by the reaction escapes from the geological reaction ore layer due to the density difference with the active mineral, and is recovered through the H2 recovery channel (2) penetrating the closed structure; the active mineral has the ability to fix carbon and produce hydrogen, and its components include metal oxides that react with carbon dioxide to form carbonates, and ferrous ions that react with water to generate hydrogen; The active ore includes at least one of kamanite, nickel tungsten, magnetite, and chalcopyrite; according to the depth of the stratum where carbon fixation and hydrogen production occur, the geological carbon fixation and hydrogen production structure is divided into a shallow geological carbon fixation and hydrogen production structure and a deep geological carbon fixation and hydrogen production structure; in the shallow geological carbon fixation and hydrogen production structure, the closed structure is an artificial closed layer (3); the geological reaction ore layer is an artificial sealing layer (4), including one of an abandoned open-pit mine and an abandoned underground mining tunnel; in the deep geological carbon fixation and hydrogen production structure, after H2 escapes, it gathers under the barrier of the closed structure to form a hydrogen-enriched area (5), which is recovered by the H2 recovery channel (2); the closed structure is a natural closed cap layer (6); the geological reaction ore layer is a natural mineralized sealing layer (7), including one of a natural saline layer, a depleted oil and gas reservoir, and a basalt stratum rich in natural fractures.

2. The method according to claim 1, characterized in that: When a shallow geological carbon fixation and hydrogen production site is used in step (2), in step (5), the laid pipeline is used as an H2 recovery channel to recover hydrogen and by-products; when a deep geological carbon fixation and hydrogen production site is used in step (2), in step (5), the hydrogen-enriched area is explored and the wellbore is used as an H2 recovery channel to recover hydrogen.

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