Method for accelerating mineralization and storage of carbon dioxide based on calcium ion-containing aqueous solution

Abstract

The invention provides a method for accelerating carbon dioxide mineralization and sequestration based on a calcium ion-containing aqueous solution, and relates to the technical field of carbon dioxide capture, utilization and sequestration. The method comprises the following steps: selecting a calcium-containing compound, dissolving the calcium-containing compound in water, and uniformly stirring and mixing to obtain an initial aqueous solution; the calcium ion concentration in the initial aqueous solution is within a preset calcium ion concentration range; an alkaline regulator is added into the initial aqueous solution, a target aqueous solution is obtained, and the pH value of the target aqueous solution is within a preset pH value range; injecting the target aqueous solution into formation water of a target formation through injection equipment; carbon dioxide to be sealed is injected into the formation water, and calcium ions in the target water solution and carbonate ions generated after the carbon dioxide is dissolved in the formation water are subjected to mineralization reaction to form calcium carbonate precipitates. According to the method, CO2 dissolution and carbonate conversion are effectively promoted, generation of calcium carbonate precipitates is greatly accelerated, and the key bottleneck of slow reaction kinetics of a traditional mineralization method is overcome.

Description

Technical Field

[0001] This application relates to the field of carbon dioxide capture, utilization and storage technology, and in particular to an accelerated carbon dioxide mineralization and storage method based on calcium ion-containing aqueous solution. Background Technology

[0002] Carbon dioxide sequestration is a permanent sequestration technology that converts carbon dioxide into stable carbonate minerals by simulating the weathering process of natural rocks. While this technology boasts significant advantages in safety and stability, its widespread application is still limited by technical bottlenecks such as slow reaction kinetics, high energy barriers, and low efficiency of traditional processes, making it difficult to meet the rate and economic requirements of large-scale industrial emission reduction. Therefore, developing a novel and efficient method that can significantly accelerate the mineralization reaction process is crucial. Summary of the Invention

[0003] This application aims to at least partially address one of the technical problems in the related art.

[0004] Therefore, one objective of this application is to propose an accelerated carbon dioxide mineralization and sequestration method based on a calcium ion-containing aqueous solution, comprising: selecting a calcium-containing compound, dissolving the calcium-containing compound in water and stirring to obtain an initial aqueous solution, wherein the calcium ion concentration in the initial aqueous solution is within a preset calcium ion concentration range; adding an alkaline regulator to the initial aqueous solution to obtain a target aqueous solution, wherein the pH value of the target aqueous solution is within a preset pH value range; injecting the target aqueous solution into the formation water of the target formation through an injection device; injecting the carbon dioxide to be sequestrated into the formation water, wherein the calcium ions in the target aqueous solution react with the carbonate ions generated after the carbon dioxide dissolves in the formation water to form calcium carbonate precipitate after a mineralization reaction.

[0005] In some embodiments, the calcium-containing compound is one or more of calcium chloride, calcium nitrate, calcium acetate, or calcium hydroxide.

[0006] In some embodiments, the alkalinity regulator is one or more of sodium hydroxide, potassium hydroxide, or ammonia.

[0007] In some embodiments, the preset pH range is a pH value within the range of 8–12.

[0008] In some embodiments, the preset calcium ion concentration range is 0.1-5 mol / L.

[0009] In some embodiments, before injecting the carbon dioxide to be sequestered into the formation water, the process further includes: purifying, compressing, and drying the carbon dioxide to be sequestered.

[0010] In some embodiments, after injecting the carbon dioxide to be sequestered into the formation water, the method further includes: monitoring the distribution of calcium carbonate precipitation using a downhole sonic detector, and analyzing the carbon dioxide sequestration efficiency based on the calcium carbonate precipitation distribution.

[0011] In some embodiments, the injection device includes a high-pressure injection pump and a multi-segment injection pipe having multiple injection ports at different depths for injecting the target aqueous solution into the formation water in layers.

[0012] In some embodiments, when the calcium-containing compound is dissolved in water and stirred to obtain an initial aqueous solution, a dispersant with a mass fraction of 0.01%-0.1% is added to the water. The dispersant is used to improve the dissolution rate and solubility of the calcium-containing compound.

[0013] In some embodiments, the dispersant may be polyethylene glycol or sodium dodecylbenzenesulfonate.

[0014] This application achieves at least the following beneficial effects:

[0015] 1. Significantly improves the mineralization reaction rate: By introducing an alkaline calcium-rich solution and optimizing the reaction pH environment, CO2 dissolution and carbonate conversion are effectively promoted, and the formation of calcium carbonate precipitate is greatly accelerated, overcoming the key bottleneck of slow reaction kinetics in traditional mineralization methods.

[0016] 2. High storage efficiency and good stability: This method directly realizes the conversion of CO2 to stable carbonate minerals in an aqueous environment. The stored material has stable chemical properties, no risk of leakage, and can achieve permanent carbon fixation.

[0017] 3. Simple process and strong adaptability: The process steps are simple, the operating conditions are relaxed, no complex equipment or high energy consumption is required, and it is easy to deploy and apply on a large scale in actual storage scenarios.

[0018] 4. Good environmental compatibility: The selected chemical reagents are low in cost and easy to obtain, and the reaction products are harmless to the environment, possessing good technical and economic benefits and ecological sustainability. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is an exemplary schematic diagram illustrating an embodiment of the present application of an accelerated carbon dioxide mineralization and storage method based on an aqueous solution containing calcium ions. Detailed Implementation

[0021] The embodiments of this application are described in detail below. Examples of these embodiments are shown 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 this application, and should not be construed as limiting this application.

[0022] Figure 1 This is an exemplary schematic diagram illustrating an accelerated carbon dioxide mineralization and sequestration method based on a calcium ion-containing aqueous solution, as shown in this application. Figure 1 As shown, this accelerated carbon dioxide mineralization and sequestration method based on calcium ion-containing aqueous solution includes the following steps:

[0023] S101, Select a calcium-containing compound, dissolve the calcium-containing compound in water and stir to mix evenly to obtain an initial aqueous solution, wherein the calcium ion concentration in the initial aqueous solution is within a preset calcium ion concentration range.

[0024] In this application, the calcium-containing compound may be selected from one or more of calcium chloride CaCl2, calcium nitrate Ca(NO3)2, calcium acetate Ca(CH3COO)2, or calcium hydroxide Ca(OH)2.

[0025] Among them, calcium chloride and calcium nitrate have high solubility, making them suitable for rapidly constructing high-concentration Ca. 2+ The system uses calcium acetate and calcium hydroxide, which are low in cost and produce no harmful byproducts after reaction, making them suitable for applications in ecologically sensitive areas. In practice, the ratio can be flexibly adjusted according to raw material costs, transportation conditions, and geological characteristics. For example, calcium chloride is preferred in high-salinity formations, while calcium hydroxide can be used in combination to reduce the impact of salinity in freshwater formations.

[0026] In this application, the preset calcium ion concentration range is 0.1-5 mol / L. When the concentration is below 0.1 mol / L, insufficient calcium source leads to incomplete mineralization and decreased storage efficiency; when the concentration is above 5 mol / L, premature precipitation of calcium salts is likely to occur, clogging the injection pipeline or formation pores. To ensure stable concentration, an online ion concentration monitor can be used for real-time detection, and concentration deviations can be dynamically corrected by adjusting the dosage of calcium-containing compounds.

[0027] In this application, when the calcium-containing compound is dissolved in water and stirred to obtain an initial aqueous solution, a dispersant with a mass fraction of 0.01%-0.1% is added to the water. The dispersant is used to improve the dissolution rate and solubility of the calcium-containing compound.

[0028] The dispersant used is either polyethylene glycol or sodium dodecylbenzenesulfonate.

[0029] S102, an alkaline regulator is added to the initial aqueous solution to obtain the target aqueous solution, wherein the pH value of the target aqueous solution is within a preset pH range.

[0030] In this application, the alkalinity regulator is one or more of sodium hydroxide (NaOH), potassium hydroxide (KOH), and ammonia (NH3·H2O).

[0031] In this application, the preset pH range is a pH value between 8 and 12.

[0032] Sodium hydroxide and potassium hydroxide have high adjustment efficiency and can quickly raise the pH value, making them suitable for scenarios that require emergency adjustment of the reaction environment. Ammonia water is mildly alkaline, and excess ammonia water can react with CO2 to form ammonium salts, which will not cause excessive alkalinity of the formation. In practical applications, the regulator should be selected according to the target pH value requirements: if the pH value needs to be raised to above 10, sodium hydroxide should be used first; if the pH value needs to be maintained in a mild range of 8-9, ammonia water can be used.

[0033] This invention significantly improves the reaction rate and storage efficiency by carrying out a mineralization reaction under alkaline conditions. Its mechanism of action mainly includes the following three aspects:

[0034] 1. Promotes carbon dioxide dissolution and hydration: An alkaline environment provides a large amount of OH-. - It can neutralize the H2 produced by CO2 dissolution. + This shifts the dissolution equilibrium to the right, significantly increasing the concentration of CO2 in the aqueous phase and providing sufficient reactants for continuous mineralization.

[0035] 2. Increase carbonate ion concentration: Alkaline conditions promote the fractional ionization equilibrium of carbonate. To generate CO3 2- The direction of movement significantly increases the CO3 concentration in the solution. 2- Concentration, accelerates Ca 2+ +CO3 2- →The rate of the CaCO3↓ precipitation reaction.

[0036] 3. Suppressing the negative impact of hydrogen ions on nucleation: Maintaining an alkaline environment with low H+ ions. + Concentration, reduce H + With CO3 2- Combined with the regeneration of HCO3 - This ensures the possibility of ineffective consumption of carbonate ions and guarantees continuous nucleation and crystal growth of calcium carbonate.

[0037] S103, the target aqueous solution is injected into the formation water of the target formation through the injection device.

[0038] The injection equipment includes a high-pressure injection pump and a multi-segment injection pipe. The multi-segment injection pipe has multiple injection ports at different depths, which are used to inject the target aqueous solution into the formation water in layers.

[0039] The injection port is equipped with a one-way valve to prevent formation water backflow from clogging the pipeline. At the same time, the injection rate of each section is controlled by a flow regulating valve to achieve "layered quantitative injection".

[0040] S104 involves injecting carbon dioxide to be sealed into formation water. Calcium ions in the target aqueous solution react with carbonate ions generated after carbon dioxide dissolves in the formation water to form calcium carbonate precipitate.

[0041] In this application, before injecting the carbon dioxide to be sequestered into the formation water, the process further includes: purifying, compressing, and drying the carbon dioxide to be sequestered.

[0042] Purification treatment involves using amine absorption or membrane separation to remove impurities (such as H2S, SO2, dust, etc.) from CO2, ensuring that the CO2 purity reaches 99.5% or higher, and avoiding impurities from affecting the mineralization reaction or corroding the equipment.

[0043] Among them, compression treatment: CO2 is compressed to a supercritical state of 15-25 MPa through a multi-stage compressor. Supercritical CO2 has higher solubility and diffusivity, which can accelerate the mixing rate with formation water.

[0044] Drying process: Using an adsorption dryer (such as a molecular sieve dryer) to remove moisture from CO2, preventing moisture from combining with impurities to form acidic substances that could corrode the injection pipes or the rock formation.

[0045] During the injection process, CO2 rapidly dissolves and ionizes in the alkaline formation aqueous phase to generate CO3. 2 -, with Ca in the target aqueous solution 2+ A mineralization reaction occurs, producing a white CaCO3 precipitate. To promote reaction uniformity, an "alternating injection" mode can be used. For example, inject the target aqueous solution for 30 minutes, then inject CO2 for 30 minutes, and repeat the cycle until the injection volume reaches the design requirements.

[0046] The process includes injecting carbon dioxide into the formation water to be stored, followed by monitoring the distribution of calcium carbonate precipitation using a downhole acoustic detector, and analyzing the carbon dioxide storage efficiency based on this distribution. Specifically, the downhole acoustic detector measures changes in sound velocity and amplitude, and uses acoustic inversion models (such as tomography) to quantitatively interpret the spatial saturation distribution of calcium carbonate within the target storage zone. Through integral calculations, the total volume and mass of the precipitated calcium carbonate can be obtained. Based on the chemical reaction formula (Ca... 2+ +CO3 2The molar mass relationship of CaCO3↓ (approximately 44 kg of carbon dioxide is stored for every 100 kg of calcium carbonate) can be used to accurately calculate the total amount of carbon dioxide permanently stored through the mineralization reaction. This is the most direct quantitative indicator for evaluating storage efficiency.

[0047] This application achieves at least the following beneficial effects:

[0048] 1. Significantly improves the mineralization reaction rate: By introducing an alkaline calcium-rich solution and optimizing the reaction pH environment, CO2 dissolution and carbonate conversion are effectively promoted, and the formation of calcium carbonate precipitate is greatly accelerated, overcoming the key bottleneck of slow reaction kinetics in traditional mineralization methods.

[0049] 2. High storage efficiency and good stability: This method directly realizes the conversion of CO2 to stable carbonate minerals in an aqueous environment. The stored material has stable chemical properties, no risk of leakage, and can achieve permanent carbon fixation.

[0050] 3. Simple process and strong adaptability: The process steps are simple, the operating conditions are relaxed, no complex equipment or high energy consumption is required, and it is easy to deploy and apply on a large scale in actual storage scenarios.

[0051] 4. Good environmental compatibility: The selected chemical reagents are low in cost and easy to obtain, and the reaction products are harmless to the environment, possessing good technical and economic benefits and ecological sustainability.

[0052] In the description of this application, 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", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0053] 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 application, "multiple" means two or more, unless otherwise explicitly specified.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. 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.

[0055] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An accelerated carbon dioxide mineralization sequestration method based on aqueous solutions containing calcium ions, characterized in that, The method comprises the following steps: selecting a calcium-containing compound, dissolving the calcium-containing compound in water and stirring to mix uniformly to obtain an initial aqueous solution, wherein the concentration of calcium ions in the initial aqueous solution is within a preset calcium ion concentration range; adding an alkaline adjusting agent to the initial aqueous solution to obtain a target aqueous solution, wherein the pH value of the target aqueous solution is within a preset pH value range; injecting the target aqueous solution into formation water in a target formation through an injection device; injecting carbon dioxide to be stored into the formation water, wherein the calcium ions in the target aqueous solution and carbonate ions generated after the carbon dioxide is dissolved in the formation water undergo a mineralization reaction to form calcium carbonate precipitates.

2. The method of claim 1, wherein, The calcium-containing compound is one or more of calcium chloride, calcium nitrate, calcium acetate or calcium hydroxide.

3. The method of claim 2, wherein, The alkaline adjusting agent is one or more of sodium hydroxide, potassium hydroxide or ammonia water.

4. The method of claim 3, wherein, The preset pH value range is a pH value within the range of 8-12.

5. The method of claim 4, wherein, The preset calcium ion concentration range is 0.1-5 mol / L.

6. The method according to any one of claims 1-5, characterized in that, Before the step of injecting carbon dioxide to be stored into the formation water, the method further comprises the steps of: purifying, compressing and drying the carbon dioxide to be stored.

7. The method of claim 6, wherein, After the step of injecting carbon dioxide to be stored into the formation water, the method further comprises the steps of: monitoring the distribution of calcium carbonate precipitates by a downhole acoustic detector and analyzing the storage efficiency of carbon dioxide based on the distribution of calcium carbonate precipitates.

8. The method of claim 1, wherein, The injection device comprises a high-pressure injection pump and a multi-section injection pipe having a plurality of injection ports at different depths for stratified injection of the target aqueous solution into the formation water.

9. The method of claim 1, wherein, When the calcium-containing compound is dissolved in water and stirred to mix uniformly to obtain an initial aqueous solution, a dispersing agent with a mass fraction of 0.01%-0.1% is added to the water, and the dispersing agent is used to improve the dissolution rate and solubility of the calcium-containing compound.

10. The method of claim 9, wherein, The dispersing agent is selected from polyethylene glycol or sodium dodecyl benzene sulfonate.

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