A CO2 foam stabilizing material, its preparation method and application

Abstract

The application provides a CO2 foam flooding foam stabilizing material and a preparation method and application thereof, and belongs to the technical field of chemical oil displacement. The CO2 foam flooding foam stabilizing material is obtained by steam explosion treatment of a preparation raw material; the preparation raw material comprises, in percentage by mass, 75-85% of plant biomass waste powder, 5-20% of alkali, 0.1-0.5% of a functional additive and the balance of water; and the functional additive is a long-chain alkyl imidazole bromide ionic liquid. The multi-component system composed of cellulose and other natural active components in the plant biomass waste is used, the plant biomass particles are rapidly activated and the surface structure is regulated through steam explosion treatment under the action of alkali and the functional additive, the particle dispersibility is improved while the multi-component synergistic advantage is retained, the plant biomass particles can be used to cooperatively build a stable CO2 foam system with a surfactant, and the foam stabilizing effect is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of chemical flooding technology, specifically to a CO2 foam flooding and stabilizing material, its preparation method, and its application. Background Technology

[0002] Carbon dioxide (CO2) flooding is a crucial technology for enhancing oil recovery, particularly suitable for low-permeability, ultra-low-permeability, and high-water-cut reservoirs. Compared to traditional waterflooding, CO2 has advantages such as low density, strong diffusion capacity, and easy entry into micropores. However, due to its significantly lower viscosity than crude oil and formation water, CO2 exhibits higher mobility. In heterogeneous reservoirs, it readily penetrates rapidly along high-permeability layers, natural fractures, or dominant flow channels, leading to severe gas channeling and reduced oil recovery efficiency. To address these issues, CO2 foam flooding has emerged as a vital technique for suppressing gas channeling and improving mobility control. This technology disperses the continuous gas phase into numerous discrete microbubbles by forming stable CO2 foam in the formation. This foam generates high flow resistance and the Jamin effect in the porous medium, effectively reducing CO2 mobility, increasing the seepage resistance of high-permeability channels, and forcing subsequent displacement media into previously unaffected or low-affected areas, thereby expanding the displacement volume and improving oil recovery. Therefore, constructing a CO2 foam system with good stability, high plugging capability, and excellent formation adaptability is key to achieving efficient CO2 oil displacement and effectively preventing gas channeling. The long-term stability of the foam system depends primarily on the stability of the foam liquid film and the integrity of the interfacial structure; thus, improving foam stability has become the core focus of CO2 foam flooding technology research.

[0003] Surfactants are the main foaming components in CO2 foam systems. They reduce gas-liquid interfacial tension, promote CO2 dispersion in the aqueous phase, and form an adsorption film at the gas-liquid interface, enabling the system to rapidly generate a large number of bubbles. However, the interfacial film formed solely by surfactants is relatively thin, with limited mechanical strength and interfacial viscoelasticity. Under complex reservoir conditions such as high temperature, high salinity, and the presence of crude oil, liquid film drainage, bubble coalescence, and foam collapse are likely to occur. To further improve foam stability, it is usually necessary to introduce foam stabilizing materials that can synergize with surfactants into the foaming system. Foam stabilizing materials can extend foam life and improve foam retention capacity and flow resistance in porous media by increasing liquid film viscosity, enhancing interfacial film mechanical strength, increasing interfacial film viscoelasticity, slowing down liquid film drainage rate, and inhibiting bubble coalescence and gas diffusion.

[0004] Currently, foam stabilizing materials used in CO2 foam flooding systems mainly include polymers, inorganic nanoparticles, gels, and natural bio-based materials. The mechanisms of action of different types of foam stabilizing materials vary, but generally they all improve the stability and plugging ability of foam under complex geological conditions by enhancing the stability of the foam liquid film, delaying liquid film drainage, inhibiting bubble aggregation, and slowing gas diffusion. Although the above-mentioned foam stabilizing materials can improve the stability of CO2 foam systems to a certain extent, polymer materials generally have limited temperature and salt resistance and require high injection pressure; inorganic nanoparticles are prone to aggregation and sedimentation, and their synergy with surfactants is greatly affected by the dispersion state; gel materials suffer from complex construction processes and insufficient deep-seated transport capabilities. Therefore, developing novel foam stabilizing materials that are abundant in sources, environmentally friendly, have simple preparation processes, and can form good synergistic effects with surfactants has become an important research direction in the field of CO2 foam flooding. In recent years, a large amount of research has been conducted both domestically and internationally on natural plant biomass and its active components. Currently, plant biomass materials used in foam regulation and plugging mainly include cellulose ethers such as hydroxyethyl cellulose and carboxymethyl cellulose, microcrystalline cellulose, regenerated cellulose, nanocellulose, and cellulose materials modified by carboxylation. Some studies also utilize natural plant fibers or plant-derived particles as foam stabilizers. Research shows that these natural plant biomass materials can synergistically interact with surfactants to improve foam film stability and enhance foam plugging capabilities. However, existing natural plant biomass foam stabilizers still have certain limitations. On the one hand, current research mainly focuses on cellulose carboxylation, TEMPO oxidation, graft polymerization, and hydrophobic modification to improve the interfacial activity and dispersion properties of the materials. These modification methods typically involve multiple chemical reactions, resulting in complex processes, high reagent consumption, and high preparation costs, which are not conducive to large-scale applications. On the other hand, most studies focus on the single component of cellulose. However, plant biomass, in addition to cellulose, also contains hemicellulose, lignin, and small amounts of natural active components. The compositional ratios and microstructures of different plant sources vary significantly, and their interfacial behavior and synergistic foam stabilization mechanisms with surfactants lack systematic research.

[0005] Therefore, fully utilizing the inherent composition and structural advantages of plant biomass to achieve excellent foam stability while reducing complex chemical modifications remains a pressing technical problem to be solved in this field. Summary of the Invention

[0006] In view of the technical problems existing in the background art, the present invention provides a CO2 foam stabilizing material, its preparation method and application, aiming to solve the technical problems of complex preparation process, high cost, limited synergy with surfactants and poor CO2 foam stabilization ability of existing foam stabilizing materials.

[0007] In a first aspect, the present invention provides a CO2 foam stabilizing material, which is obtained by steam explosion treatment of raw materials; The raw materials for preparation include, by mass percentage: 75%~85% plant biomass waste powder, 5%~20% alkali, 0.1%~0.5% functional additives, and the balance water; The functional additives are long-chain alkyl imidazolium bromide ionic liquids.

[0008] Preferably, the plant biomass waste is waste from medicinal plants; the waste from medicinal plants includes at least one of the following: Asarum waste, Costus root waste, Licorice waste, Akebia waste, and Aristolochia debilis waste.

[0009] Preferably, the particle size of the plant biomass waste powder is ≤75μm.

[0010] Preferably, the alkali includes at least one of sodium carbonate, sodium bicarbonate, calcium carbonate, ethylenediamine, and triethylamine.

[0011] Preferably, the functional additives include at least one of 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium bromide, and 1-hexadecyl-3-methylimidazolium bromide.

[0012] Secondly, the present invention provides a method for preparing a CO2 foam stabilizing material, comprising the following steps: Plant biomass waste powder is mixed with alkali, functional additives and water, and then subjected to steam explosion treatment to obtain CO2 foam stabilizing material; the steam explosion treatment pressure is 0.5MPa~10MPa, and the pressure holding time is 0.1~2h.

[0013] Preferably, the plant biomass waste powder is obtained by crushing plant biomass waste and then passing it through a 200-mesh sieve.

[0014] Preferably, after the steam explosion treatment is completed, the steam explosion products are further subjected to solid-liquid separation. The solid is washed with deionized water until neutral and then dried to obtain CO2 foam stabilizing material.

[0015] Thirdly, the present invention provides a CO2 foam system, comprising, by mass percentage, 0.5% to 2% of the CO2 foam stabilizing material described in the first aspect, 0.2% to 0.8% of anionic surfactant, and the balance being mineralized water.

[0016] Fourthly, the present invention provides a method for preparing a CO2 foam system, comprising the following steps: uniformly mixing the CO2 foam stabilizing material, anionic surfactant and mineralized water as described in the first aspect to obtain a foaming solution; stirring the foaming solution under a CO2 atmosphere to obtain a CO2 foam system.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The CO2 foam displacement and stabilization material provided by this invention abandons the traditional single-component utilization of cellulose and directly utilizes a multi-component system composed of cellulose and other natural active components in plant biomass waste. Through steam explosion and synergistic treatment with alkali / functional additives, the plant biomass particles are rapidly activated and their surface structure is regulated. While retaining the synergistic advantages of the multi-component system, the particle dispersibility is improved, enabling it to synergistically construct a stable CO2 foam system with surfactants, thereby improving the anti-channeling effect and oil displacement efficiency of CO2 foam displacement.

[0018] The CO2 foam flooding and stabilizing material provided by this invention makes full use of plant biomass waste resources and has the advantages of wide availability of raw materials, simple preparation process, low cost, and environmental friendliness. It can be applied to CO2 foam flooding profile control, cross-contamination prevention, and improving oil recovery. Attached Figure Description

[0019] Figure 1 These are scanning electron microscope images of the waste powder of Aquilaria sinensis in Example 2 of the present invention under 20-micrometer and 10-micrometer scales; Figure 2 The images are scanning electron microscope images of the foam-stabilizing material prepared in Example 2 of the present invention at 20-micrometer and 10-micrometer scales. Figure 3 The Fourier transform infrared spectra of the waste powder of costus root and the prepared CO2 foam stabilizing material in Example 2 of this invention are shown. Figure 3 In the diagram, A represents waste powder from incense wood, and B represents the CO2 foam stabilizing material obtained from it. Detailed Implementation

[0020] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0021] To address the technical problems of existing foam stabilizing materials, such as complex preparation processes, high costs, limited synergy with surfactants, and poor CO2 foam stabilization capabilities, this invention provides a CO2 foam-driven foam stabilizing material, its preparation method, and its application. This material utilizes a multi-component system composed of cellulose and other natural active components from plant biomass waste. Through steam explosion and synergistic treatment with alkali / functional additives, the plant biomass particles are rapidly activated and their surface structure is regulated. While retaining the synergistic advantages of the multi-component system, particle dispersibility is improved, enabling it to synergistically construct a stable CO2 foam system with surfactants. This enhances the anti-channeling effect and oil displacement efficiency of CO2 foam flooding.

[0022] In a first aspect, embodiments of the present invention provide a CO2 foam stabilizing material, which is obtained from raw materials through steam explosion treatment; The raw materials for preparation include, by mass percentage: 75%~85% plant biomass waste powder, 5%~20% alkali, 0.1%~0.5% functional additives, and the balance water; The functional additives are long-chain alkyl imidazolium bromide ionic liquids.

[0023] In the technical solution of this invention embodiment, the present invention utilizes a combination of steam explosion treatment and the synergistic effect of alkali and functional additives to activate and modify plant biomass waste, resulting in a high-performance foam-stabilized material. The role of the alkali is to swell, cut, and break the long molecular chains in plant biomass molecules under high temperature and pressure, releasing more hydroxyl groups. The role of the functional additives is to assist in dissolving the long carbon chains in plant biomass molecules, releasing more functional groups. The steam explosion process, in addition to providing a high-temperature and high-pressure environment, also allows for the instantaneous release of internal pressure in the plant biomass during depressurization, enabling the plant biomass powder particles to form a loose structure from the inside out, which is beneficial for dispersion within the foam film to form a stable structure. Plant biomass waste, besides cellulose, also retains lignin, hemicellulose, and naturally active components derived from plants. The synergistic effect between these different components enables the multifunctionalization of the functional groups on the material surface, generating CO2-loving and hydrophilic functional groups, which is beneficial for the stability of the foam film.

[0024] Furthermore, in some embodiments, the plant biomass waste is the waste of medicinal plants; the waste of medicinal plants includes at least one of Asarum waste, Costus root waste, Licorice waste, Akebia waste, and Aristolochia debilis waste.

[0025] In the technical solution of this invention, waste products from medicinal plants such as Asarum, Aucklandia, Glycyrrhiza, Akebia, and Aristolochia are selected as raw materials, realizing resource reuse. These medicinal plant waste products contain active components such as natural polysaccharides, saponins, lactones, and amides, as well as some organic acids that pose a high potential hazard to the human body. While their use as traditional Chinese medicine is restricted, their use in the industrial field is unimpeded. After being treated with steam explosion, these substances fully expose their internal active functional groups, enabling them to increase liquid film viscosity, reduce surface tension, and improve foaming performance, and can form a good synergistic effect with anionic surfactants.

[0026] Furthermore, in some embodiments, the particle size of the plant biomass waste powder is ≤75μm to ensure sufficient reaction during the steam explosion treatment process.

[0027] Furthermore, in some embodiments, the base includes at least one selected from sodium carbonate, sodium bicarbonate, calcium carbonate, ethylenediamine, and triethylamine.

[0028] Furthermore, in some embodiments, the functional additives include at least one of 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium bromide, and 1-hexadecyl-3-methylimidazolium bromide.

[0029] Secondly, embodiments of the present invention provide a method for preparing a CO2 foam stabilizing material, comprising the following steps: Plant biomass waste powder is mixed with alkali, functional additives and water, and then subjected to steam explosion treatment to obtain CO2 foam stabilizing material; the steam explosion treatment pressure is 0.5MPa~10MPa, and the pressure holding time is 0.1~2h.

[0030] In the technical solution of this invention embodiment, after the plant biomass waste powder is treated by steam explosion under the action of alkali and functional additives, its microstructure undergoes significant changes. The particle surface becomes loose, the specific surface area increases, and more CO2-loving and hydrophilic functional groups are exposed, which can be better adsorbed at the gas-liquid interface, significantly improving the stability of CO2 foam.

[0031] Furthermore, in some embodiments, the plant biomass waste powder is obtained by crushing plant biomass waste and then passing it through a 200-mesh sieve.

[0032] Furthermore, in some embodiments, after the steam explosion treatment is completed, the steam explosion products are further subjected to solid-liquid separation, the solid is washed with deionized water until neutral, and then dried to obtain CO2 foam stabilizing material.

[0033] Thirdly, embodiments of the present invention provide a CO2 foam system, comprising, by mass percentage, 0.5% to 2% of the CO2 foam stabilizing material described in the first aspect, 0.2% to 0.8% of anionic surfactant, and the balance being mineralized water.

[0034] Furthermore, in some embodiments, the anionic surfactant includes sodium α-olefin sulfonate.

[0035] Furthermore, in some embodiments, the mineralization degree of the mineralized water is 20,000 to 80,000 mg / L.

[0036] Fourthly, embodiments of the present invention provide a method for preparing a CO2 foam system, comprising the following steps: uniformly mixing the CO2 foam stabilizing material, anionic surfactant, and mineralized water described in the first aspect to obtain a foaming solution; stirring the foaming solution under a CO2 atmosphere to obtain a CO2 foam system.

[0037] Furthermore, in some embodiments, the stirring speed is 5000~10000 rpm, and the stirring time is 2~3 min.

[0038] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0039] Example 1 A method for preparing a CO2 foam stabilizing material, the specific steps of which are as follows: (1) At room temperature, crush the waste of Asarum with a pulverizer, pass it through a 200-mesh sieve, and collect the powder of Asarum waste; (2) At room temperature, 75 grams of Asarum waste powder were placed into a temperature- and pressure-resistant stainless steel sealed container equipped with a pressure gauge and a pressure relief valve that could be rolled and rotated. (3) At room temperature, 20 g of sodium carbonate, 0.1 g of 1-dodecyl-3-methylimidazolium bromide and 4.9 g of water were placed in a beaker and stirred at 600 rpm for 10 minutes to obtain 25 g of additive mixture; then, the 25 g of additive mixture was placed in the above-mentioned stainless steel sealed container. (4) After sealing the stainless steel sealed container, heat it until the pressure gauge shows that the internal pressure has risen to 0.5 MPa; keep the pressure of the stainless steel sealed container constant and rotate it at a speed of 2 revolutions / second for 0.1 hours to make the mixture inside it fully mixed. (5) Open the pressure relief valve of the above-mentioned stainless steel sealed container to cause instantaneous depressurization and steam explosion. After solid-liquid separation, washing and drying, the asarum waste-based foam stabilized material is obtained.

[0040] Example 2 A method for preparing a CO2 foam stabilizing material, the specific steps of which are as follows: (1) At room temperature, crush the waste of incense wood with a crusher, pass it through a 200-mesh sieve, and collect the powder of incense wood waste; (2) At room temperature, 75 grams of incense waste powder were placed into a temperature- and pressure-resistant stainless steel sealed container equipped with a pressure gauge and a pressure relief valve that could be rolled and rotated. (3) At room temperature, 10 g of sodium carbonate, 0.2 g of 1-tetradecyl-3-methylimidazolium bromide and 14.8 g of water were placed in a beaker and stirred at 600 rpm for 10 minutes to obtain 25 g of additive mixture; then, the 25 g of additive mixture was placed in the above-mentioned stainless steel sealed container. (4) After sealing the stainless steel sealed container, heat it until the pressure gauge shows that the internal pressure has risen to 10 MPa; keep the pressure of the stainless steel sealed container constant and rotate it at a speed of 2 revolutions / second for 2 hours to ensure that the mixture inside is fully mixed. (5) Open the pressure relief valve of the above-mentioned stainless steel sealed container to cause instantaneous depressurization and steam explosion. After solid-liquid separation, washing and drying, the wood fragrance waste-based foam stabilized material is obtained.

[0041] Figure 1 These are scanning electron microscope images of the incense waste powder in this embodiment under 20-micrometer and 10-micrometer scales; Figure 2 The images show scanning electron microscope (SEM) images of the foam stabilized material prepared in this embodiment at 20 μm and 10 μm scales. It can be seen that the waste sandalwood powder appears as smooth columnar particles at both 20 μm and 10 μm scales. After treatment with "gas explosion + alkali / functional additives," the microstructure of the foam stabilized material particles becomes significantly looser, the surface area increases, and a large number of exposed fibers with sizes as low as 130 nm are generated at the ends. This indicates that the foam stabilized material possesses good dispersibility.

[0042] Figure 3 The figures show the Fourier transform infrared spectra of the waste powder of *Saussurea costus* and the prepared CO2 foam stabilizing material in this embodiment; A in the figure represents the waste powder of *Saussurea costus*, and B in the figure represents the prepared CO2 foam stabilizing material. Figure 3 777 cm -1 813 cm -1 The peaks at the two locations are characteristic vibrational peaks of the carbon long-chain skeleton. After the steam explosion treatment, the two characteristic peaks were significantly weakened, proving that the carbon long-chain skeleton was cut into smaller segments. Figure 3 2855 cm -1 2926 cm -1 It is a characteristic peak of -CH2, 716 cm⁻¹ -1 The characteristic peak of -CH2 is also present, but it is more common on the side chains, indicating that a large number of -CH2-CH2- chains and fragments with numerous -CH2 side chains are generated after the steam explosion. The hydrophobicity of these fragments helps to improve the affinity of the foam stabilizing material for CO2. Cellulose crystal forms are often divided into type I and type II. Type II cellulose is characterized by stronger hydrophilicity, better dispersibility, and a looser structure. Its strong characteristic peak in FT-IR is at 1460 cm⁻¹. -1 place, Figure 3 1460 cm -1 The characteristic peak at this location indicates that the foam-stabilizing material contains type II cellulose, verifying that... Figure 2 The morphological results. Figure 3 1106 cm -1 1163 cm -1 The characteristic peak of -COC- is at 1737 cm⁻¹.-1 The characteristic peak of hemicellulose acetyl groups indicates that under the action of alkali and functional additives, the original long chain structure of plant biomass breaks down, and other functional groups wrapped inside are released to the surface. The CO2 affinity and hydrophilicity of these functional groups are beneficial to improving foam stability. Figure 3 1243 cm -1 1520 cm -1 and 1632 cm -1 The characteristic peaks belong to the CO stretching vibration of the aromatic ether bond (Ar-OC), the vibration of the aromatic ring skeleton (C=C), and the vibration of the conjugated aromatic ring, respectively. The peaks of these functional groups did not change before and after treatment, indicating that some functional groups of chemical substances in the costus waste were retained.

[0043] Example 3 A method for preparing a CO2 foam stabilizing material, the specific steps of which are as follows: (1) At room temperature, crush the licorice waste with a pulverizer, pass it through a 200-mesh sieve, and collect the licorice waste powder; (2) At room temperature, 85 grams of licorice waste powder were placed into a temperature- and pressure-resistant stainless steel sealed container equipped with a pressure gauge and a pressure relief valve that could be rolled and rotated. (3) At room temperature, 5 g of calcium carbonate, 0.5 g of 1-hexadecyl-3-methylimidazolium bromide and 9.5 g of water were placed in a beaker and stirred at 600 rpm for 10 minutes to obtain 15 g of additive mixture; then, 15 g of additive mixture was placed in the above-mentioned stainless steel sealed container. (4) After sealing the stainless steel sealed container, heat it until the pressure gauge shows that the internal pressure has risen to 5 MPa; keep the pressure of the stainless steel sealed container constant and rotate it at a speed of 2 revolutions / second for 1 hour to make the mixture inside it fully mixed. (5) Open the pressure relief valve of the above-mentioned stainless steel sealed container to cause instantaneous depressurization and steam explosion. After solid-liquid separation, washing and drying, licorice waste-based foam stabilized material is obtained.

[0044] Example 4 A method for preparing a CO2 foam stabilizing material, the specific steps of which are as follows: (1) At room temperature, crush the waste wood akebia with a crusher, pass it through a 200-mesh sieve, and collect the waste wood akebia powder; (2) At room temperature, 80 grams of waste powder of Akebia quinata was placed into a temperature- and pressure-resistant stainless steel sealed container equipped with a pressure gauge and a pressure relief valve that can be rolled and rotated. (3) At room temperature, 7 g of ethylenediamine, 0.2 g of 1-dodecyl-3-methylimidazolium bromide and 12.8 g of water were placed in a beaker and stirred at 600 rpm for 10 minutes to obtain 20 g of additive mixture; then, the 20 g of additive mixture was placed in the above-mentioned stainless steel sealed container. (4) After sealing the stainless steel sealed container, heat it until the pressure gauge shows that the internal pressure has risen to 8.0 MPa; keep the pressure of the stainless steel sealed container constant and rotate it at a speed of 2 revolutions / second for 1.5 hours to make the mixture inside it fully mixed. (5) Open the pressure relief valve of the above-mentioned stainless steel sealed container to cause instantaneous depressurization and steam explosion. After solid-liquid separation, washing and drying, the wood waste-based foam stabilized material is obtained.

[0045] Example 5 A method for preparing a CO2 foam stabilizing material, the specific steps of which are as follows: (1) At room temperature, crush the waste of *Ipomoea aquatica* using a pulverizer, pass it through a 200-mesh sieve, and collect the powder of the waste. (2) At room temperature, 75 grams of waste powder of *Ipomoea aquatica* was placed into a heat-resistant and pressure-resistant stainless steel sealed container equipped with a pressure gauge and a pressure relief valve that can be rolled and rotated. (3) At room temperature, 20 g of triethylamine, 0.3 g of 1-tetradecyl-3-methylimidazolium bromide and 4.7 g of water were placed in a beaker and stirred at 600 rpm for 10 minutes to obtain 25 g of additive mixture; then, 25 g of additive mixture was placed in the above-mentioned stainless steel sealed container. (4) After sealing the stainless steel sealed container, heat it until the pressure gauge shows that the internal pressure has risen to 4.0 MPa; keep the pressure of the stainless steel sealed container constant and rotate it at a speed of 2 revolutions / second for 2 hours to make the mixture inside it fully mixed. (5) Open the pressure relief valve of the above-mentioned stainless steel sealed container to cause instantaneous depressurization and steam explosion. After solid-liquid separation, washing and drying, the Tianxianteng waste-based foam stabilized material is obtained.

[0046] Comparative Example 1 The difference between this comparative example and Example 2 is that 25 grams of the additive mixture is replaced with 25 grams of water. The specific steps are as follows: (1) At room temperature, crush the waste of incense wood with a crusher, pass it through a 200-mesh sieve, and collect the powder of incense wood waste; (2) At room temperature, 75 grams of incense waste powder were placed into a temperature- and pressure-resistant stainless steel sealed container equipped with a pressure gauge and a pressure relief valve that could be rolled and rotated. (3) At room temperature, put 25 grams of water into the above-mentioned stainless steel sealed container; (4) After sealing the stainless steel sealed container, heat it until the pressure gauge shows that the internal pressure has risen to 10 MPa; keep the pressure of the stainless steel sealed container constant and rotate it at a speed of 2 revolutions / second for 2 hours to ensure that the mixture inside is fully mixed. (5) Open the pressure relief valve of the above-mentioned stainless steel sealed container to cause instantaneous depressurization and steam explosion. After solid-liquid separation, washing and drying, the wood fragrance waste-based foam stabilized material is obtained.

[0047] Comparative Example 2 The difference between this comparative example and Example 2 is that in step (4), after the stainless steel sealed container is sealed, its internal pressure is kept at atmospheric pressure; the parameters of the other steps are the same as those in Example 2.

[0048] Comparative Example 3 The difference between this comparative example and Example 2 is that 1-tetradecyl-3-methylimidazolium bromide was not added, and in step (3), "10 g sodium bicarbonate and 0.2 g 1-tetradecyl-3-methylimidazolium bromide" were replaced with "10.2 g sodium bicarbonate"; the other step parameters were the same as in Example 2.

[0049] Comparative Example 4 The difference between this comparative example and Example 2 is that sodium bicarbonate was not added, and in step (3), “10 g sodium bicarbonate and 0.2 g 1-tetradecyl-3-methylimidazolium bromide” were replaced with “10.2 g 1-tetradecyl-3-methylimidazolium bromide”; the other step parameters are the same as in Example 2.

[0050] Comparative Example 5 The difference between this comparative example and Example 2 is that the insulator waste is not activated: At room temperature, crush the waste wood incense using a pulverizer, pass it through a 200-mesh sieve, and collect the waste wood incense powder as a foam stabilizer.

[0051] Comparative Example 6 The difference between this comparative example and Example 2 is that "wood waste" is replaced with "microcrystalline cellulose", while the rest of the steps and parameters are the same as in Example 2.

[0052] Performance testing To further illustrate the foam-stabilizing effect of the foam-stabilizing material of the present invention, the following experiments were conducted: The warping blender method is one of the industry standards for evaluating foam stabilization effects. 0.5 g of surfactant AOS and 1.0 g of the foam stabilizing material obtained in Examples 1-5 and Comparative Examples 1-6 were added to 98.5 mL of mineralized water (50000 mg / L sodium chloride aqueous solution). The mixture was stirred at 400 rpm for 10 minutes under a CO2 atmosphere to obtain a foaming solution. Using a high-speed foaming machine, the foaming solution was stirred at 8000 rpm for 3 minutes under a CO2 atmosphere to obtain foam. The foam was poured into a 500 mL standard graduated cylinder, and the half-life of the precipitate was recorded, as shown in Table 1 below.

[0053] Table 1

[0054] The data in Table 1 show that the CO2 foam-driving and stabilizing materials obtained from plant biomass waste in Examples 1-5 of the present invention have good foam stabilizing performance.

[0055] The lack of alkali and functional additives in Comparative Example 1 prevented the molecular structure of the plant biomass waste from swelling, cutting, and breaking during the preparation process. Although the steam explosion process could give the material in Comparative Example 1 a loose state, it could not provide enough functional groups for foam stabilization.

[0056] Comparative Example 2 lacked high-temperature and high-pressure conditions during the preparation of its foam-stabilizing material, resulting in insufficient energy for the alkali and functional additives to act on the molecular structure of plant biomass. The absence of a steam explosion process also meant that the material in Comparative Example 2 lacked a loose state and exhibited poor foam-stabilizing performance.

[0057] Comparative Example 3 used only an aqueous solution of alkali in the preparation of the foam-stabilizing material, without adding any functional additives. Under high temperature and pressure, the alkali released more hydroxyl groups, which improved the hydrophilicity of the material in Comparative Example 3, but the lack of other hydrophobic and hydrophilic functional groups resulted in its low foam-stabilizing performance.

[0058] Comparative Example 4 used only functional additives in the preparation of the foam-stabilizing material, without adding any alkali. The functional additives help to dissolve the long carbon chains in plant biomass molecules and release functional groups, but the lack of alkali to swell, cut, and break the long carbon chains results in low dissolution efficiency and an inability to provide enough functional groups to stabilize the foam.

[0059] Comparative Example 5 only pulverized plant biomass waste, and its molecular structure remained in its original natural state. Neither the surface functional groups nor the molecular structure could stabilize the gas-liquid interfacial tension of the foam liquid film, resulting in poor foam stabilization performance.

[0060] Comparative Example 6 uses microcrystalline cellulose as its raw material. After treatment with "gas explosion + alkali / functional additives", the cellulose molecules swell, cut, and break, which changes its microstructure and generates some hydrophilic functional groups, slightly improving its foam stabilizing performance. However, lacking hydrophobic and hydrophilic functional groups provided by other chemical substances, the synergistic foam stabilizing performance cannot be demonstrated.

[0061] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A CO2 foam stabilizing material, characterized in that, It is obtained by steam explosion treatment of raw materials; The raw materials for preparation, by mass percentage, include: 75%~85% plant biomass waste powder, 5%~20% alkali, 0.1%~0.5% functional additives, and the balance being water; The functional additive is a long-chain alkylimidazolium bromide ionic liquid; The plant biomass waste is waste from medicinal plants; the waste from medicinal plants includes at least one of the following: Asarum waste, Costus root waste, Licorice waste, Akebia waste, and Aristolochia debilis waste. The particle size of the plant biomass waste powder is ≤75μm.

2. The CO2 foam stabilizing material according to claim 1, characterized in that, The alkali includes at least one of sodium carbonate, sodium bicarbonate, calcium carbonate, ethylenediamine, and triethylamine.

3. The CO2 foam displacement and stabilization material according to claim 1, characterized in that, The functional additives include at least one of 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium bromide, and 1-hexadecyl-3-methylimidazolium bromide.

4. The preparation method of the CO2 foam displacement and stabilization material according to any one of claims 1 to 3, characterized in that, Includes the following steps: Plant biomass waste powder is mixed with alkali, functional additives and water, and then subjected to steam explosion treatment to obtain CO2 foam displacement and stabilization material. The pressure for the steam explosion treatment is 0.5MPa~10MPa, and the pressure holding time is 0.1~2h.

5. The method for preparing CO2 foam stabilizing material according to claim 4, characterized in that, The plant biomass waste powder is obtained by crushing plant biomass waste and passing it through a 200-mesh sieve.

6. The method for preparing the CO2 foam stabilizing material according to claim 4, characterized in that, After the steam explosion treatment is completed, the steam explosion products are further subjected to solid-liquid separation. The solid is washed with deionized water until neutral and then dried to obtain CO2 foam stabilizing material.

7. A CO2 foam system, characterized in that, The product comprises, by weight percentage, 0.5% to 2% of the CO2 foam stabilizing material as described in any one of claims 1 to 3, 0.2% to 0.8% of the anionic surfactant, and the balance being mineralized water.

8. The method for preparing the CO2 foam system as described in claim 7, characterized in that, Includes the following steps: The CO2 foam stabilizing material, anionic surfactant, and mineralized water are mixed evenly to obtain a foaming solution; the foaming solution is stirred and foamed under a CO2 atmosphere to obtain a CO2 foam system.

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