Plugging material suitable for carbon sequestration top and preparation method thereof
By combining permeable polyurethane with carbonation-resistant Portland cement, the sealing and ecological compatibility issues of the top sealing material in extreme environments were resolved, achieving efficient carbon sequestration and ecological protection, and reducing the risk of CO2 leakage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-14
AI Technical Summary
Existing top sealing materials are difficult to stably seal for long periods under extreme environments such as high temperature and pressure, CO2 erosion, and incompatibility with formation media. They also have poor ecological compatibility, resulting in a high risk of CO2 leakage and affecting the benefits of geological sealing and ecological protection.
By combining permeable polyurethane with anti-carbonation Portland cement and employing a special formulation and mixing process, a fused mixture is formed, enhancing the material's sealing properties and eco-compatibility. This mixture is suitable for the preparation of top-sealing materials for carbon sequestration.
It significantly improves the weather resistance and sealing performance of the sealing material, reduces the risk of CO2 leakage, reduces soil pollution, protects vegetation growth, and achieves a balance between long-term storage and ecological protection.
Smart Images
Figure CN121850506A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of carbon dioxide sequestration materials technology, and in particular to a top sealing material suitable for carbon sequestration and its preparation method. Background Technology
[0002] Top sealing materials, as the "last line of defense" in geological storage systems, directly determine whether CO2 leakage will occur. According to IPCC data, if sealing failure leads to a 1% annual CO2 leakage rate, the emission reduction benefits of geological storage will decrease by more than 30%. Therefore, the research and optimization of sealing materials has become a core bottleneck for the implementation of CCUS technology. From the perspective of the characteristics of geological storage scenarios, top sealing needs to cope with complex and extreme environments: First, the high temperature and high pressure conditions of the formation require materials with excellent thermal stability and compressive strength; second, the long-term corrosive effect of CO2, CO2 dissolves in formation water to form carbonic acid, which easily reacts with traditional sealing materials, leading to material cracking and increased permeability (for example, the permeability of ordinary Portland cement can increase by 2-3 orders of magnitude within 1 year in a CO2 environment); third, the compatibility of formation media, high salinity fluids (salt content exceeding 100g / L) in saline aquifers will accelerate material corrosion, and residual hydrocarbons in depleted oil and gas reservoirs may undergo physical swelling or chemical reactions with the materials, destroying the sealing structure. Traditional sealing materials are no longer sufficient to meet the requirements for long-term stable storage. While early pure cement slurries offer good fluidity and high strength, they are brittle and have poor crack resistance, easily developing microcracks under varying formation stress. Asphalt-based sealing materials, although flexible, lack high-temperature resistance (softening easily above 80°C) and have low bonding strength with formation rocks. Polymer-modified cement, while improving toughness, suffers from poor polymer-cement compatibility and unclear long-term CO2 erosion resistance. Industry surveys indicate that the effective sealing life of existing sealing materials is generally less than 20 years, far below the 100+ year service life required for geological storage. Furthermore, the need for surface ecological protection further raises the technical threshold for sealing materials. Some carbon sequestration areas are located in farmland or ecologically sensitive areas. If the sealing materials have problems such as heavy metal leaching or excessive alkalinity, they will pollute the soil and groundwater and affect the growth of the above-ground vegetation. At the same time, some sequestration projects need to take into account the construction of monitoring wells or surface development in the later stage, requiring the sealing materials to be repairable and environmentally friendly.
[0003] In summary, developing top-sealing materials that combine high sealing performance, resistance to extreme environments, long lifespan, and ecological compatibility has become a key technological direction for achieving large-scale application of CCUS technology. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention discloses a top sealing material suitable for carbon sequestration and its preparation method, effectively solving issues such as insufficient sealing performance and poor ecological compatibility. It provides a reliable and highly adaptable technical means for sealing the top of carbon sequestration systems. This not only significantly improves the long-term sealing safety of carbon sequestration and reduces the risk of CO2 leakage, but also significantly reduces the pollution of soil physicochemical structures by the sealing material, ensuring the growth of overlying vegetation. While achieving the functional goals of carbon sequestration, it also considers ecological protection, possessing outstanding environmental benefits and extremely high engineering application value, providing key support for the large-scale implementation of CCUS technology.
[0005] The technical solution adopted by this invention is as follows: A top-sealing material suitable for carbon sequestration and its preparation method, comprising the following steps: Step S1: Weigh the pretreated coarse aggregate, Portland cement, permeable polyurethane, and water; wherein the mass of the Portland cement is 14% to 21% of the mass of the coarse aggregate, the mass of the permeable polyurethane is less than 2% of the total mass of the Portland cement and water, and the mass of the water is 3% to 6% of the total mass of the coarse aggregate and Portland cement. Step S2: Pour the coarse aggregate into the mixer and mix. Then add Portland cement and penetrating polyurethane in sequence and mix until combined. Step S3: Water is added in two batches during the stirring process. The first batch contains 40%-50% of the water, and the second batch contains the remaining water. After stirring, a top sealing material suitable for carbon sequestration is obtained.
[0006] This technical solution, through special design of the material formula, incorporates highly permeable polyurethane, which, together with aggregates and cement, forms a fusion that can significantly reduce the damage and pollution of the soil structure caused by the sealing material. It can also effectively take into account the root development and normal growth of the upper plants, achieving a balance between ecological protection and functional needs.
[0007] As a further improvement of the present invention, the Portland cement is PO 42.5 grade and mainly serves as a binder.
[0008] As a further improvement of the present invention, the aggregate is made of solid limestone particles with a particle size of 10-30 mm.
[0009] As a further improvement of the present invention, the permeable polyurethane is obtained by mixing polyol and isocyanate in a stoichiometric ratio of NCO / OH of 1:1. The permeable polyurethane after stirring is ensured to be uniformly mixed and not separated into layers.
[0010] As a further improvement of the present invention, the stirring speed in steps S2 and S3 is ≤30r / min to ensure that the coarse aggregate is evenly dispersed and not damaged.
[0011] As a further improvement of the present invention, in step S2, after adding Portland cement, the mixture is stirred for at least 30 seconds. After the Portland cement covers the surface of the aggregate, penetrating polyurethane is added.
[0012] As a further improvement of the present invention, in step S2, after adding the permeable polyurethane, continue stirring for 1-2 minutes until the permeable polyurethane is initially fused with Portland cement and aggregate and there are no lumps, then proceed to step S3.
[0013] As a further improvement of the present invention, after adding water for the first time in step S3, stir and observe the surface state of the aggregate until the aggregate is initially coated with slurry and there is no exposed dry aggregate. Then add the remaining water and continue stirring for 2-3 minutes.
[0014] As a further improvement of the present invention, the mass of the Portland cement is 17% to 21% of the mass of the coarse aggregate, the mass of the permeable polyurethane is 1.3% to 1.5% of the total mass of the Portland cement and water, and the mass of the water is 5% to 6% of the total mass of the coarse aggregate and Portland cement.
[0015] As a further improvement of the present invention, the mass of the Portland cement is 17% of the mass of the coarse aggregate, the mass of the permeable polyurethane is 1.4% of the total mass of the Portland cement and water, and the mass of the water is 5% of the total mass of the coarse aggregate and Portland cement.
[0016] As a further improvement of the present invention, step S4 is also included, in which the mixed material from step S3 is added to the well to be sealed, plants are planted, and the well is naturally maintained for 42 days. Furthermore, the mixed material is injected into the well at a low height, approximately 200mm from the bottom, to prevent damage.
[0017] The present invention also discloses a top sealing material suitable for carbon storage, which is prepared by the preparation method of the top sealing material suitable for carbon storage as described above.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: By employing the technical solution of this invention, the risk of CO2 leakage is effectively avoided through the synergistic effect of permeable polyurethane and anti-carbonation Portland cement, significantly improving the sealing performance and weather resistance. Secondly, it enhances ecological compatibility. The materials used in the technical solution of this invention do not leach heavy metals, have controllable alkalinity, and are suitable for planting concrete structures. This reduces damage to the physical and chemical structure of the soil in the storage area while providing root growth space for the upper vegetation, thus balancing carbon sequestration function and surface ecological protection. Attached Figure Description
[0019] Figure 1 This is a flowchart illustrating the implementation of an embodiment of the present invention. Detailed Implementation
[0020] The preferred embodiments of the present invention will be described in further detail below. Example 1
[0021] A method for preparing a reinforcing material suitable for carbon-sequestered rock interfaces, such as Figure 1 As shown, it includes the following steps: Step 1: Accurately weigh 1553g of coarse aggregate, 217g of Portland cement, 4g of penetrating polyurethane and 76g of deionized water (the cement mass is 14% of the aggregate mass, and the deionized water mass is 5% of the total aggregate and cement mass). Step 2: Pour 1553g of coarse aggregate into a mixer and mix at a low speed, less than 30r / min; Step 3: Add 217g of cement to the mixer; Step 4: Add 4g of penetrating polyurethane to the mixer; wherein the penetrating polyurethane is obtained by reacting MDI (Diphenylmethane diisocyanate) with polyether polyol in an NCO / OH stoichiometric ratio. Step 5: Add water in two batches. First, add 38g of deionized water until the aggregate is initially coated with slurry, i.e., there is no exposed dry aggregate. Then, add another 38g of deionized water, which is the remaining water. Step 6: Pour the mixture into the mold and place it in a curing chamber (temperature 20±2℃, humidity ≥95%). Test the compressive strength after curing for 7 days and 28 days. Example 2
[0022] Based on Example 1, the preparation steps of this example include: Step 1: Accurately weigh 1553g of coarse aggregate, 264g of Portland cement, 5g of penetrating polyurethane and 92g of deionized water (the cement mass is 17% of the aggregate mass, and the deionized water mass is 5% of the total aggregate and cement mass). Step 2: Pour 1553g of coarse aggregate into a mixer and mix at a low speed, less than 30r / min; Step 3: Add 264g of cement to the mixer; Step 4: Add 5g of penetrating polyurethane to the mixer; Step 5: Add water in two batches. First, add 46g of deionized water until the aggregate is initially coated with slurry, i.e., there is no exposed dry aggregate. Then, add another 46g of deionized water, which is the remaining water. Step 6: Pour the mixture into the mold and place it in a curing chamber (temperature 20±2℃, humidity ≥95%). Test the compressive strength after curing for 7 days and 28 days. Example 3
[0023] Based on Example 1, the preparation steps of this example include: Step 1: Accurately weigh 1553g of coarse aggregate, 311g of Portland cement, 6g of penetrating polyurethane and 109g of deionized water (the cement mass is 20% of the aggregate mass, and the deionized water mass is 5% of the total aggregate and cement mass). Step 2: Pour 1553g of coarse aggregate into a mixer and mix at a low speed, less than 30r / min; Step 3: Add 311g of cement to the mixer; Step 4: Add 6g of penetrating polyurethane to the mixer; Step 5: Add water in two batches. First, add 54g of deionized water until the aggregate is initially coated with slurry, i.e., there is no exposed dry aggregate. Then, add 55g of deionized water, which is the remaining water. Step 6: Pour the mixture into the mold and place it in a curing chamber (temperature 20±2℃, humidity ≥95%). Test the compressive strength after curing for 7 days and 28 days.
[0024] The compressive strength of the materials obtained in Examples 1 to 3 is shown in Table 1. It can be seen that after seven days of curing, the compressive strength can reach more than 7 MPa, and after 28 days, the strength can reach more than 8 MPa.
[0025] Table 1. Compressive strength results of materials in Examples 1-3 Example maintenance time 7 days 28 days Example 1 7.1MPa 8.2MPa Example 2 8.9MPa 9.8MPa Example 3 10.1MPa 10.9 MPa Example 4
[0026] Based on Example 2, the preparation steps of this example include: Step 1: Accurately weigh 1553g of coarse aggregate, 264g of Portland cement, 5g of penetrating polyurethane and 92g of deionized water (the cement mass is 17% of the aggregate mass, and the deionized water mass is 5% of the total aggregate and cement mass). Step 2: Pour 1553g of coarse aggregate into a mixer and mix at a low speed, less than 30r / min; Step 3: Add 264g of cement to the mixer; Step 4: Add 5g of penetrating polyurethane to the mixer; Step 5: Add water in two batches. First, add 46g of deionized water until the aggregate is initially coated with slurry, i.e., there is no exposed dry aggregate. Then, add another 46g of deionized water, which is the remaining water. Step 6: Pour the mixture into the molds and plant alfalfa, star grass, Bermuda grass, and basp grass separately for 42 days of natural growth.
[0027] Based on this embodiment, natural soil was used as a control for comparative experiments. The root length and coverage of the plants in this embodiment and natural soil after 42 days are shown in Tables 2 and 3. It can be seen that the carbon sequestration top sealing material using the technical solution of this embodiment can not only perform carbon sequestration, but is also more suitable for the growth of upper vegetation than natural soil, and has better remediation and environmental friendliness.
[0028] Table 2. Plant growth in Example 4
[0029] Table 3. Plant growth in comparative natural soil.
[0030] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a top sealing material suitable for carbon sequestration, characterized in that, Includes the following steps: Step S1: Weigh the pretreated coarse aggregate, Portland cement, permeable polyurethane, and water; wherein the mass of the Portland cement is 14% to 21% of the mass of the coarse aggregate, the mass of the permeable polyurethane is less than 2% of the total mass of the Portland cement and water, and the mass of the water is 3% to 6% of the total mass of the coarse aggregate and Portland cement. Step S2: Pour the coarse aggregate into the mixer and mix. Then add Portland cement and penetrating polyurethane in sequence and mix until combined. Step S3: Water is added in two batches during the stirring process. The first batch contains 40%-50% of the water, and the second batch contains the remaining water. After stirring, a top sealing material suitable for carbon sequestration is obtained.
2. The method for preparing a top sealing material for carbon sequestration according to claim 1, characterized in that: The Portland cement is PO 42.5 grade; the aggregate is solid limestone particles with a particle size of 10-30mm.
3. The method for preparing a top sealing material for carbon sequestration according to claim 2, characterized in that: The permeable polyurethane is obtained by mixing polyol and isocyanate in a stoichiometric ratio of 1:1 (NCO / OH).
4. The method for preparing a top sealing material for carbon sequestration according to claim 1, characterized in that: The stirring speed in steps S2 and S3 is ≤30 r / min.
5. The method for preparing a top sealing material for carbon sequestration according to claim 1, characterized in that: In step S2, after adding Portland cement, stir for at least 30 seconds. After the Portland cement covers the surface of the aggregate, add penetrating polyurethane.
6. The method for preparing a top sealing material suitable for carbon sequestration according to claim 5, characterized in that: In step S2, after adding the penetrating polyurethane, continue stirring for 1-2 minutes. Once the penetrating polyurethane has initially blended with the Portland cement and aggregates and there are no lumps, proceed to step S3.
7. The method for preparing a top sealing material suitable for carbon sequestration according to claim 6, characterized in that: After adding water for the first time in step S3, stir and observe the surface condition of the aggregate. When the aggregate is initially coated with slurry and there are no exposed dry aggregates, add the remaining water and continue stirring for 2-3 minutes.
8. The method for preparing a top sealing material suitable for carbon sequestration according to any one of claims 1 to 7, characterized in that: The Portland cement accounts for 17% of the mass of the coarse aggregate, the permeable polyurethane accounts for 1.4% of the total mass of the Portland cement and water, and the water accounts for 5% of the total mass of the coarse aggregate and Portland cement.
9. The method for preparing a top sealing material for carbon sequestration according to claim 8, characterized in that: It also includes step S4, which involves adding the mixed material from step S3 into the well to be sealed, planting plants, and allowing it to grow naturally for 42 days.
10. A top sealing material suitable for carbon sequestration, characterized in that: It is prepared using the preparation method for top sealing material suitable for carbon sequestration as described in any one of claims 1 to 9.