Preparation method and application of carbon dioxide hydrate accelerant

Abstract

The invention discloses a preparation method and application of a carbon dioxide hydrate accelerant. The preparation method of the carbon dioxide hydrate accelerant comprises the following steps: (1) mixing a vinyl alcohol aqueous solution with a vinyl monomer to obtain a mixed reaction system; (2) mixing the mixed reaction system with a cross-linking agent and an initiator, and carrying out a cross-linking reaction to obtain modified polyvinyl alcohol; (3) mixing the modified polyvinyl alcohol with carbon nanotubes to obtain a mixture; and (4) carrying out hot pressing or freeze drying treatment on the mixture to obtain the carbon dioxide hydrate accelerant. The vinyl monomer modified polyvinyl alcohol modified nano carbon tube type carbon dioxide hydrate accelerant disclosed by the invention is applied to carbon dioxide capture and hydrate generation thereof. The vinyl monomer is introduced to modify the polyvinyl alcohol, and the application of the carbon nanotubes is combined, so that the performance of the accelerant is remarkably improved.

Description

Technical Field

[0001] This invention relates to a method for preparing a carbon dioxide hydrate accelerator, as well as its preparation method and application, belonging to the technical field of hydrate accelerators and their preparation. Background Technology

[0002] In the capture and storage (CMS) of carbon dioxide, hydrate formation is a crucial pathway for efficient storage. However, CMS hydrate formation is often influenced by various environmental factors, particularly under different temperature and pressure conditions, where its formation efficiency is significantly limited. Especially in deep-sea and frigid regions, the rapid drop in temperature not only restricts the hydrate formation rate but also increases the energy consumption of the capture equipment, threatening its stability and potentially leading to wear and malfunctions. These problems can cause not only economic losses but also safety hazards, thus affecting the effective storage of carbon dioxide.

[0003] For carbon dioxide capture under harsh environmental conditions, traditional hydrate promoters can improve the hydrate formation rate to some extent, but they generally lack adaptability to different pH values ​​and complex hydrochemical characteristics, limiting their practical application effectiveness. Although traditional promoters have achieved certain performance under specific experimental conditions, in complex application environments such as the deep sea and high-altitude cold regions, due to changes in temperature, pressure, and liquid phase composition, the performance of the promoters often becomes unstable and cannot meet the stringent requirements of actual production.

[0004] Therefore, it is particularly important to develop a novel, self-adaptive hydrate promoter. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a carbon dioxide hydrate promoter, as well as the preparation method and its application.

[0006] This invention modifies polyvinyl alcohol by introducing vinyl monomers and combines this with the application of carbon nanotubes to significantly improve the performance of the accelerator. This accelerator can flexibly adjust its physicochemical properties under varying environmental conditions, effectively promoting the formation of carbon dioxide hydrate and improving its capture efficiency. Its design is specifically tailored to the challenges of harsh environments, ensuring excellent accelerator performance at low temperatures and requiring lower dosages, thereby significantly enhancing overall economic efficiency and environmental friendliness. This invention provides more reliable technical support for carbon dioxide capture and storage technologies, and is expected to significantly enhance carbon sequestration effects in extreme environments, promoting the advancement and widespread application of related technologies.

[0007] The present invention provides a method for preparing a carbon dioxide hydrate promoter, comprising the following steps:

[0008] (1) Mix the aqueous solution of vinyl alcohol with the vinyl monomer to obtain a mixed reaction system; (2) The mixed reaction system is mixed with a crosslinking agent and an initiator to carry out a crosslinking reaction, thereby obtaining modified polyvinyl alcohol; (3) The modified polyvinyl alcohol is mixed with carbon nanotubes to obtain a mixture; (4) The mixture is subjected to hot pressing or freeze drying to obtain carbon dioxide hydrate promoter.

[0009] In the above method, the mass concentration of polyvinyl alcohol in the polyvinyl alcohol aqueous solution can be 0.05~0.15 g / mL, specifically 0.05 g / mL, 0.1 g / mL, or 0.125 g / mL.

[0010] In the above method, the vinyl monomer is selected from acrylic acid and / or acrylamide; The mass ratio of the vinyl monomer to the polyvinyl alcohol can be 1 to 3:10, specifically 1:5 or 1:8.

[0011] In the above method, the crosslinking agent is selected from glutaraldehyde and / or diisopropanolamine; The initiator is selected from potassium persulfate and / or ammonium persulfate.

[0012] In the above method, the mass ratio of the initiator to the polyvinyl alcohol can be 0.1~0.5:100, specifically 0.1:100, 0.25:100, or 0.5:100; The temperature of the crosslinking reaction can be 10~80℃, specifically 50, 60℃ or 50~60℃, and the time can be 1~5 hours.

[0013] In the above method, the mass ratio of the carbon nanotubes to the modified polyvinyl alcohol can be 1~10:100, specifically 2:100, 4:100, 7.5:100 or 2~7.5:100.

[0014] In the above method, the mixing is performed by ultrasonic treatment in step (3). The frequency of the ultrasonic treatment can be 20kHz~40kHz, specifically 20kHz, 25kHz, 30kHz, or 40kHz. The processing power can be 100W~300W, specifically 100W, 150W, 200W, or 300W. The processing time can be 30 minutes~60 minutes, specifically 30 minutes, 45 minutes, or 60 minutes.

[0015] In the above method, in step (4), the temperature of hot pressing or freeze drying can be 50℃~100℃, specifically 70℃, 50℃~70℃, or 70℃~100℃, and the processing time can be 5~18 hours, specifically 12 hours, 5~12 hours, or 12~18 hours.

[0016] The present invention also provides a vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared by the above method.

[0017] The vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter described in this invention is applied to carbon dioxide capture and its hydrate formation.

[0018] The present invention has the following beneficial effects: 1. This invention uses acrylic acid or acrylamide, a monomer used in the modification of polyvinyl alcohol (PVA), as the monomer, which enables the formation of a polymer network with good elasticity and strength during polymerization. By adding crosslinking agents (such as glutaraldehyde or diisopropanolamine) for chemical crosslinking, the molecular structure of PVA is improved, enhancing its durability and stability under low-temperature conditions. Furthermore, the introduction of carbon nanotubes significantly improves the electrical and thermal conductivity of the material, optimizing the composite properties of the polymer and enabling it to exhibit superior catalytic activity and reaction efficiency in carbon dioxide capture and hydrate formation.

[0019] 2. The promoter obtained by this invention combines the flexibility of modified polyvinyl alcohol and the conductivity of carbon nanotubes in its structure. This composite structure can reduce the nucleation energy barrier of hydrates and promote the rapid formation of hydrates through physical and chemical interactions during the formation of carbon dioxide hydrates. Modified polyvinyl alcohol provides the necessary hydration environment, while carbon nanotubes enhance the stability of bubbles inside the hydrates and improve the ability to capture carbon dioxide, thus realizing a highly efficient carbon dioxide hydration process.

[0020] 3. The preparation method of this invention features unique reaction conditions and steps, especially the multiple roles played in the chemical crosslinking reaction and ultrasonic treatment. First, by controlling the amount of crosslinking agent and initiator added, the crosslinking density and chain length of the polymer can be precisely adjusted, thereby optimizing the physicochemical properties of the polymer. Second, the ultrasonic treatment not only ensures the uniform dispersion of carbon nanotubes but also promotes the interaction and bonding between the nanomaterials and the polymer through the mechanical action of ultrasound, improving the overall performance of the accelerator. Furthermore, the selection of temperature and time in the hot-pressing or freeze-drying preparation process further enhances the structural stability of the accelerator and its promoting effect on carbon dioxide hydrate. Attached Figure Description

[0021] Figure 1The induction time curve is shown for a vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared in Example 1 of this invention.

[0022] Figure 2 The induction time curve is shown for a vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared in Example 2 of this invention.

[0023] Figure 3 The induction time curve of a vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared in Example 3 of the present invention.

[0024] Figure 4 The induction time curve is shown for a vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared in Example 4 of this invention.

[0025] Figure 5 This is the induction time curve of carbon dioxide hydrate in a pure water system.

[0026] Figure 6 The induction time curve of the vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared for Comparative Example 1.

[0027] Figure 7 The induction time curve of the vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared for Comparative Example 2.

[0028] Figure 8 The induction time curve of the vinyl monomer-modified polyvinyl alcohol-modified carbon nanotube carbon dioxide hydrate promoter prepared for Comparative Example 3. Detailed Implementation

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0030] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0031] Example 1 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 1g of vinyl monomer acrylic acid to the solution while stirring to ensure thorough mixing; (2) Add 0.01 g of crosslinking agent glutaraldehyde and 0.01 g of initiator potassium persulfate to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.25g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0032] Example 2 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 1g of vinyl monomer acrylic acid to the solution while stirring to ensure thorough mixing; (2) Add glutaraldehyde, a crosslinking agent, with a mass of 0.02 g, and potassium persulfate, an initiator, to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.25g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0033] Example 3 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 2g of vinyl monomer acrylic acid to the solution while stirring to ensure thorough mixing; (2) Add glutaraldehyde, a crosslinking agent, with a mass of 0.02 g, and potassium persulfate, an initiator, to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.25g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0034] Example 4 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 2g of vinyl monomer acrylic acid to the solution while stirring to ensure thorough mixing; (2) Add glutaraldehyde, a crosslinking agent, with a mass of 0.02 g, and potassium persulfate, an initiator, to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.5g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0035] Comparative Example 1 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 2g of vinyl monomer styrene to the solution while stirring to ensure thorough mixing; (2) Add glutaraldehyde, a crosslinking agent, with a mass of 0.02 g, and potassium persulfate, an initiator, to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.25g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0036] Comparative Example 2 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 2g of vinyl monomer acrylic acid to the solution while stirring to ensure thorough mixing; (2) Add formaldehyde, a crosslinking agent, with a mass of 0.02 g, and potassium persulfate, an initiator, to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.25g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0037] Comparative Example 3 (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water to form a homogeneous solution; gradually add 2g of vinyl monomer acrylic acid to the solution while stirring to ensure thorough mixing; (2) Add 0.02 g of crosslinking agent glutaraldehyde and 0.02 g of initiator ammonium persulfate to the reaction system in step (1), and continue to react at room temperature (25°C, the same below) for 2 hours to promote the crosslinking reaction; (3) After the reaction is complete, 12.5g of modified polyvinyl alcohol is mixed with 0.25g of carbon nanotubes and treated with ultrasound at a frequency of 30kHz and a power of 200W for 45 minutes. (4) The mixture was hot-pressed at 70°C for 2 hours to obtain vinyl monomer modified polyvinyl alcohol modified carbon nanotube carbon dioxide hydrate promoter.

[0038] Experimental Example 1: The samples from Examples 1-4 and Comparative Example 3 were subjected to CO2 hydrate induction experiments. The specific procedure was as follows: the CO2 hydrate formation experiment was conducted under isochoric and isothermal conditions (250 cm⁻¹). 3 The experiments were conducted at 0.5 °C. Hydrates formed in three solutions: aqueous solution (blank), Examples 1-4, and Comparative Examples 1-3. NaCl at a concentration of 0.1 mmol / L was used as the background salt solution. First, solutions of different systems were injected separately into pressure vessels to form hydrates; before immersing the vessels in a cooling bath maintained at 10 °C, air was removed from the autoclave by purging with gaseous CO2 through several compressions and decompressions. CO2 was then injected into the vessels to pressurize the system to 3.5 MPa. Before the hydrate experiments, CO2 was thoroughly dissolved in the solution using a magnetic stirrer at 500 rpm. The induction time for CO2 hydrate formation depended on the time span from the temperature drop to the equilibrium temperature (8.2 °C at 3.4 MPa) to the significant temperature rise at which rapid hydrate formation occurred. The results are as follows: Figure 1-8 As shown, the induction time of Examples 1-4 was lower than that of the blank example and Comparative Examples 1-3, proving that the vinyl monomer modified polyvinyl alcohol modified carbon nanotube type carbon dioxide hydrate promoter described in this invention has an excellent effect on promoting hydrate formation.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon dioxide hydrate promoter, comprising the following steps: (1) Mix the aqueous solution of vinyl alcohol with the vinyl monomer to obtain a mixed reaction system; (2) The mixed reaction system is mixed with a crosslinking agent and an initiator to carry out a crosslinking reaction, thereby obtaining modified polyvinyl alcohol; (3) The modified polyvinyl alcohol is mixed with carbon nanotubes to obtain a mixture; (4) The mixture is subjected to hot pressing or freeze drying to obtain carbon dioxide hydrate promoter.

2. The method according to claim 1, characterized in that, The polyvinyl alcohol in the aqueous solution has a mass percentage concentration of 0.05~0.15 g / mL.

3. The method according to claim 1 or 2, characterized in that, The vinyl monomer is selected from acrylic acid and / or acrylamide; The mass ratio of the vinyl monomer to the polyvinyl alcohol is 1~3:

10.

4. The method according to any one of claims 1-3, characterized in that, The crosslinking agent is selected from glutaraldehyde and / or diisopropanolamine; The initiator is selected from potassium persulfate and / or ammonium persulfate; The cross-linking reaction is carried out at a temperature of 10~80℃ for 1~5 hours.

5. The method according to any one of claims 1-4, characterized in that, The mass ratio of the initiator to the polyvinyl alcohol is 0.1~0.5:

100.

6. The method according to any one of claims 1-5, characterized in that, The mass ratio of the carbon nanotubes to the modified polyvinyl alcohol is 1~10:

100.

7. The method according to any one of claims 1-6, characterized in that, In step (3), the mixing is carried out by ultrasonic treatment. The frequency of the ultrasonic treatment is 20kHz~40kHz, the processing power is 100W~300W, and the processing time is 30 minutes~60 minutes.

8. The method according to any one of claims 1-7, characterized in that, In step (4), the temperature of hot pressing or freeze drying is 50℃~100℃, and the processing time is 5~18 hours.

9. The carbon dioxide hydrate promoter prepared by any one of claims 1-8.

10. The application of the carbon dioxide hydrate promoter according to claim 9 in carbon dioxide capture and its hydrate formation.

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