A nano-pore silicalite-1 water-based porous liquid and a preparation method and application thereof

Abstract

The application provides a kind of nanopore Silicalite-1 water-based porous liquid and its preparation method and application, belong to water-based porous liquid capture, recover natural gas technical field.The nanopore Silicalite-1 water-based porous liquid provided, including spherical nanopore Silicalite-1 and steric hindrance solvent;The particle size of the spherical nanopore Silicalite-1 is 90-120nm, and the pore size is 0.7-0.8nm;The steric hindrance solvent is water.The nanopore Silicalite-1 provided by the application has small particle size and is easy to disperse in steric hindrance solvent, the microporous inner surface is hydrophobic, the outer surface is hydrophilic, and is compatible with water, using water as steric hindrance solvent is economical and environmentally friendly.It can be known from the data of examples that the nanopore Silicalite-1 water-based porous liquid obtained by the application does not settle for 15 days, and has good stability.

Description

Technical Field

[0001] This invention belongs to the field of water-based porous liquid capture and recovery of natural gas, specifically relating to a nanoporous Silicalite-1 water-based porous liquid, its preparation method and application. Background Technology

[0002] During crude oil extraction, natural gas dissolved in the oil may escape due to temperature and pressure changes. Therefore, timely capture and recovery of natural gas during oil extraction can not only save energy, create economic benefits, reduce costs, and achieve rational energy utilization, but also control the emission of secondary greenhouse gases (methane gas), reduce environmental pollution, and have both economic and environmental benefits.

[0003] Currently, existing associated gas capture and recovery technologies both domestically and internationally mainly fall into two categories: one relies on external power equipment, such as pressure regulating valve recovery equipment, but due to factors such as complex equipment structure, high energy consumption, and large investment, it cannot be widely applied; the other utilizes the properties and energy of the recovery medium itself, such as membrane separation technology, but the associated gas recovery efficiency is low. Therefore, there is a need for energy-saving, environmentally friendly, and high-recovery-rate associated gas capture and recovery technologies for oilfields. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a nanoporous Silicalite-1 water-based porous fluid, its preparation method, and its application. The nanoporous Silicalite-1 water-based porous fluid provided by this invention has high capture and recovery rates of associated gas in oil fields, and is energy-saving and environmentally friendly.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] This invention provides a nanoporous Silicalite-1 water-based porous liquid, comprising spherical nanoporous Silicalite-1 and a sterically hindered solvent;

[0007] The spherical nanoporous Silicalite-1 has a particle size of 90–120 nm and a pore size of 0.7–0.8 nm.

[0008] The steric solvent is water.

[0009] Preferably, the specific surface area of ​​the spherical nanopore Silicalite-1 is 680–700 m². 2 / g, with a pore volume of 0.45–0.65 mL / g.

[0010] Preferably, the mass ratio of the spherical nanopore Silicalite-1 to the steric hindrance solvent is 1:5 to 12.

[0011] This invention also provides a method for preparing the nanoporous Silicalite-1 water-based porous liquid described in the above technical solution, comprising the following steps:

[0012] Spherical nanopore Silicalite-1 was mixed with a sterically hindered solvent and sonicated to obtain a water-based porous liquid containing the nanopore Silicalite-1.

[0013] The steric solvent is water.

[0014] Preferably, the preparation method of the spherical nanopore Silicalite-1 includes the following steps:

[0015] Tetraethyl silicate was added to an aqueous solution of tetrapropylammonium hydroxide to perform hydrolysis and condensation, resulting in a homogeneous mixture. The homogeneous mixture was subjected to a hydrothermal reaction to obtain a nanoporous Silicalite-1 precursor. The nanoporous Silicalite-1 precursor was calcined to obtain spherical nanoporous Silicalite-1.

[0016] The amount of tetraethyl silicate used is based on the molar amounts of silicon dioxide and ethanol produced after its hydrolysis and condensation reaction. In the homogeneous mixture, the molar ratio of tetrapropylammonium hydroxide, silicon dioxide and ethanol is 4-5:12-13:48-52.

[0017] The mass concentration of tetrapropylammonium hydroxide in the aqueous solution is 35–45 wt%.

[0018] Preferably, the hydrothermal reaction is carried out at a temperature of 85–95°C for a duration of 40–55 hours.

[0019] Preferably, the calcination temperature is 520–580°C and the time is 9–12 hours;

[0020] The calcination atmosphere is an air atmosphere.

[0021] Preferably, the calcination process further includes drying the nanoporous Silicalite-1 precursor at a temperature of 190–210°C for 1–1.75 h.

[0022] Preferably, the duration of the ultrasound is 36 to 50 hours.

[0023] The present invention also provides the application of the nanoporous Silicalite-1 water-based porous liquid prepared by the preparation method described above in the capture and recovery of natural gas.

[0024] This invention provides a nanoporous Silicalite-1 water-based porous liquid, comprising spherical nanoporous Silicalite-1 and a steric hindrance solvent; the spherical nanoporous Silicalite-1 has a particle size of 90-120 nm and a pore size of 0.7-0.8 nm; the steric hindrance solvent is water. The nanoporous Silicalite-1 provided by this invention has uniformly distributed pores, which greatly promotes the diffusion and mass transfer of methane gas during adsorption. Compared with liquids without pores, the water-based porous liquid of nanoporous Silicalite-1 significantly improves the methane storage capacity. Furthermore, the small particle size of nanoporous Silicalite-1, at the nanoscale, makes it easily dispersed in sterically hindered solvents. Using water as a sterically hindered solvent is more widely applicable, simpler, more economical, and environmentally friendly than using ionic liquids. The microporous inner surface of nanoporous Silicalite-1 is hydrophobic, while the outer surface is hydrophilic due to the distribution of hydroxyl groups, exhibiting excellent water stability and compatibility. This allows it to maintain its excellent pore structure while dispersing in water without sedimentation, resulting in a water-based porous liquid with good fluidity and stability. This forms a fluid liquid adsorption medium, improving the diffusion and mass transfer of gas molecules within the liquid and significantly increasing the solubility of gas molecules in the liquid. Simultaneously, due to its constant porosity, superior fluidity, ease of recovery, and environmental friendliness, it is likely to play an important role in wastewater treatment, biopharmaceutical delivery, and other fields in the future. Data from the examples show that the nanoporous Silicalite-1 water-based porous liquid obtained by this invention does not settle after 15 days of storage, exhibiting good stability. At 0–4 MPa, the adsorption capacity of the nanoporous Silicalite-1 water-based porous liquid for methane is 6–8 times that of pure water, and at 2–4 MPa, the adsorption capacity of the nanoporous Silicalite-1 water-based porous liquid for methane is 4–5 times that of pure water, demonstrating high efficiency in gas capture and recovery.

[0025] This invention also provides a method for preparing the nanoporous Silicalite-1 water-based porous liquid described in the above technical solution. The synthesis process is simple and the adsorption performance is good, providing reliable support for future large-scale, continuous gas capture, recovery, and separation applications. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1SEM image of the prepared nanoporous Silicalite-1 porous material;

[0028] Figure 2 SEM image of commercially available pure silica molecular sieve Silicalite-1 porous material;

[0029] Figure 3 TEM image of the prepared nanoporous Silicalite-1 porous material

[0030] Figure 4 The XRD pattern of the prepared nanoporous Silicalite-1 porous material;

[0031] Figure 5 The BET and PSD images of the nanoporous Silicalite-1 porous material are shown.

[0032] Figure 6 The images show the initial state and the actual product after standing for 15 days of the Silicalite-1 water-based porous liquid prepared in Examples 1-2 and Comparative Example 1.

[0033] Figure 7 Isothermal adsorption curves of methane on the nanoporous Silicalite-1 water-based porous liquid and pure water prepared in Examples 1 and 2.

[0034] Figure 8 The adsorption capacity characterization diagrams are for the nanoporous Silicalite-1 water-based porous liquid and nanoporous Silicalite-1 porous material prepared in Examples 1 and 2. Detailed Implementation

[0035] This invention provides a nanoporous Silicalite-1 water-based porous liquid, comprising spherical nanoporous Silicalite-1 and a sterically hindered solvent;

[0036] The spherical nanoporous Silicalite-1 has a particle size of 90–120 nm and a pore size of 0.7–0.8 nm.

[0037] The steric solvent is water.

[0038] In this invention, the spherical nanoporous Silicalite-1 has a particle size of 90–120 nm, preferably 80–110 nm, more preferably 85–105 nm, a pore size of 0.7–0.8 nm, preferably 0.72–0.76 nm, and a specific surface area of ​​preferably 680–700 m². 2 / g, more preferably 685-695m 2 / g, further preferably 694.4m2 / g, the pore volume is preferably 0.45-0.65mL / g, more preferably 0.50-0.6mL / g, and even more preferably 0.55-0.57mL / g.

[0039] In this invention, the steric hindrance solvent is water. Ionic liquids have high water solubility and are difficult to degrade, which makes them very persistent in aquatic and terrestrial environments and endangers human health. Using pure water, which has similar properties to ionic liquids, as the steric hindrance solvent for porous liquids is more economical and environmentally friendly.

[0040] In this invention, the mass ratio of the spherical nanopore Silicalite-1 to the steric hindrance solvent is preferably 1:5 to 12, more preferably 1:7 to 10, and even more preferably 1:8 to 9.

[0041] The nanoporous Silicalite-1 water-based porous liquid provided by this invention possesses the dual advantages of both nanoporous materials and fluids, exhibiting rapid heat dissipation and high pumpability. The nanoporous Silicalite-1 porous material has a large specific surface area and good hydrothermal stability, maintaining its excellent pore structure when dispersed in water without sedimentation. This results in good fluidity and stability of the water-based porous liquid, forming a fluid liquid adsorption medium that improves the diffusion and mass transfer of gas molecules within the liquid, significantly increasing the solubility of gas molecules in the liquid. Using water as a sterically hindered solvent facilitates recovery and is environmentally friendly.

[0042] This invention also provides a method for preparing the nanoporous Silicalite-1 water-based porous liquid described in the above technical solution, comprising the following steps:

[0043] Spherical nanopore Silicalite-1 was mixed with a sterically hindered solvent and sonicated to obtain a water-based porous liquid containing the nanopore Silicalite-1.

[0044] The steric solvent is water.

[0045] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0046] In this invention, the method for preparing the spherical nanopore Silicalite-1 preferably includes the following steps:

[0047] A hydrolysis-condensation reaction was carried out by adding tetraethyl silicate to an aqueous solution of tetrapropylammonium hydroxide to obtain a homogeneous mixture; the homogeneous mixture was subjected to a hydrothermal reaction to obtain a nanoporous Silicalite-1 precursor; the nanoporous Silicalite-1 precursor was calcined to obtain spherical nanoporous Silicalite-1.

[0048] In this invention, tetraethyl silicate is added to the aqueous solution of tetrapropylammonium hydroxide to carry out a hydrolysis-condensation reaction, resulting in a homogeneous mixture.

[0049] In this invention, the tetrapropylammonium hydroxide is used as a structure directing agent, and tetraethyl silicate is used as a silicon source.

[0050] In this invention, the tetraethyl silicate is hydrolyzed and condensed to obtain silicon dioxide and ethanol; the amount of tetraethyl silicate used is based on the molar amount of silicon dioxide and ethanol produced after the hydrolysis and condensation reaction; in the homogeneous mixture, the molar ratio of tetrapropylammonium hydroxide, silicon dioxide and ethanol is preferably 4-5:12-13:48-52, more preferably 4.1-4.8:12.2-12.8:49-50; the mass concentration of tetrapropylammonium hydroxide in the aqueous solution is preferably 35-45 wt%, more preferably 40 wt%.

[0051] In this invention, the tetrapropylammonium hydroxide aqueous solution is preferably obtained by dissolving tetrapropylammonium hydroxide in water. This invention does not have special requirements for the dissolution conditions; in specific embodiments, dissolution is carried out by stirring at 500 r / min for 30 min. This invention does not have special requirements for the method of adding the tetraethyl silicate; any method well-known to those skilled in the art can be used. In specific embodiments, dropwise addition is employed. In this invention, the hydrolysis-condensation reaction time is preferably 15–24 h, more preferably 18–22 h; the hydrolysis-condensation is preferably carried out under stirring conditions. This invention preferably uses a sealing film to enclose the container after adding the tetraethyl silicate for the hydrolysis-condensation reaction. The sealing film is used to prevent liquid from splashing out during stirring and to avoid introducing other impurities.

[0052] The overall chemical reaction formula for the hydrolysis and condensation of tetraethyl silicate in this invention is:

[0053] Si(OCH2CH3)4+2H2O==SiO2+4C2H5OH,

[0054] When tetraethyl silicate is added, before the hydrolysis reaction is complete, the hydrolysis product (silicic acid, Si(OH)4) begins to undergo polymerization (including polymerization between silicic acid and polymerization between silicic acid and the reactant tetraethyl silicate). After polymerization, O-Si-O bonds are formed (and may also form longer polymer chains: O-Si-O-Si-O-Si-O), crystal nuclei are formed, and then gradually polymerize to form long chains and extend into a three-dimensional framework during the hydrothermal reaction.

[0055] In this invention, the homogeneous mixture obtained after hydrothermal condensation reaction is uniform and transparent.

[0056] After obtaining a homogeneous mixture, the present invention subjectes the homogeneous mixture to a hydrothermal reaction to obtain a nanoporous Silicalite-1 precursor.

[0057] In this invention, the hydrothermal reaction temperature is preferably 85–95°C, more preferably 88–92°C, and the reaction time is preferably 40–55 h, more preferably 45–50 h. During the hydrothermal reaction, a large number of Si-O bonds form long chains to generate 3D structures, allowing the polymer to further grow into particles with larger macroscopic scales.

[0058] In this invention, the hydrothermal reaction preferably further includes solid-liquid separation and centrifugal washing of the resulting hydrothermal reaction product liquid. The solid-liquid separation is preferably performed by centrifugation; the washing solution used for centrifugal washing is preferably deionized water; the amount of deionized water used in each wash is the same as the amount of incompletely reacted supernatant removed from each centrifuge tube; preferably, centrifugation is performed 6-8 times to ensure complete removal of the solvent. The centrifugation speed is preferably 9000-11000 r / min, and the centrifugation time per cycle is preferably 15-25 min.

[0059] After obtaining the nanoporous Silicalite-1 precursor, the present invention calcines the nanoporous Silicalite-1 precursor to obtain spherical nanoporous Silicalite-1.

[0060] In this invention, the calcination temperature is preferably 520–580°C, more preferably 550–570°C, and the holding time is preferably 9–12 h, more preferably 10–11 h; the calcination atmosphere is preferably air, and the heating rate to the calcination temperature is preferably 3–6°C / min. Preferably, before calcination, this invention also includes drying the nanoporous Silicalite-1 precursor, with the drying temperature preferably 190–210°C, more preferably 200–205°C, and the drying time preferably 1–1.75 h, more preferably 1.25–1.5 h. The drying preferably includes placing the nanoporous Silicalite-1 precursor in a muffle furnace, with a heating rate preferably 3–6°C / min. In this invention, the nanoporous Silicalite-1 precursor is preferably spread evenly in a crucible, and then placed in a muffle furnace for drying and calcination. The thickness of the nanoporous Silicalite-1 precursor uniformly spread in the crucible is preferably 1–3 mm to ensure uniform heating during calcination and to facilitate gas flow to remove substances such as NH3, propylene, and H2O generated after the decomposition and vaporization of tetrapropylammonium hydroxide. This invention removes the tetrapropylammonium hydroxide structure-directing agent through calcination, yielding spherical nanoporous Silicalite-1.

[0061] In this invention, the duration of ultrasound is preferably 36–50 hours, followed by centrifugation at a speed of 6000–8000 r / min, with each centrifugation lasting 1–3 minutes and the number of centrifugations performed 1–3 times. This invention removes large particulate precipitates from the porous liquid by centrifugation, thereby allowing for the control of the mass ratio of Silicalite-1 to deionized water to prepare a nanoporous Silicalite-1 water-based porous liquid with the desired mass concentration.

[0062] This invention also provides the application of the nanoporous Silicalite-1 water-based porous liquid described in the above technical solution in the capture and recovery of natural gas.

[0063] In an embodiment of the present invention, the method for capturing and recovering natural gas preferably includes the following steps:

[0064] The temperature of the isothermal water bath was set to 15℃, and the volume of the adsorption tank was measured using the ideal gas law.

[0065] Take 2 mL of the prepared nanoporous Silicalite-1 water-based porous liquid and put it into the adsorption tank. Calculate the volume of the gas phase above the liquid surface in the adsorption tank.

[0066] The adsorption tank was pressurized in stages, and methane gas with a pressure range of 0 to 9 MPa was introduced. The adsorption capacity of the nanoporous Silicalite-1 water-based porous liquid for methane gas was analyzed and calculated by the pressure drop changes of the adsorption tank after each stage of pressurization and the corresponding gas state equation.

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. The described embodiments are only some embodiments of the present invention, and not all embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the embodiments of the present invention based on the technical essence and general principles of the present invention without creative effort should be within the protection scope of the present invention.

[0068] Prepare nanoporous Silicalite-1 materials.

[0069] 31.51 mL of 40 wt% tetrapropylammonium hydroxide aqueous solution and 40.52 mL of deionized water were mixed in a 200 mL beaker and stirred at 500 rpm for 30 min at room temperature. 38.6 mL of tetraethyl orthosilicate was added, the beaker was sealed, and stirred at room temperature for 18 h. The tetraethyl orthosilicate under alkaline conditions underwent complete hydrolysis and condensation, yielding a homogeneous and transparent mixed solution. The mixed solution was placed in a polytetrafluoroethylene liner and subjected to hydrothermal reaction at 90 °C for 48 h in a high-pressure reactor. After cooling to room temperature, the white emulsion product was centrifuged at 10000 rpm for 5 min to remove most of the solvent. The product was washed seven times with seven times the volume of water, centrifuged at 10000 rpm for 20 min, dried at 75 °C for 18 h, and ground to obtain a white solid powder.

[0070] 1.5g of white solid powder was placed in an alumina crucible and calcined in an air environment using a muffle furnace. The temperature was increased to 200℃ at 3.33℃ / min and held for 2h, and then increased to 550℃ at 5℃ / min and held for 10h to obtain nanoporous Silicalite-1 material.

[0071] Figure 1 SEM images of the prepared nanoporous Silicalite-1 porous material. From... Figure 1 As can be seen, the Silicalite-1 porous material consists of spherical particles with uniform particle size.

[0072] Figure 2 This is a SEM image of commercially available pure silica molecular sieve Silicalite-1 porous material. Figure 2 As can be seen, the material is coffin-shaped with pointed ends, with a length of 1.53 μm, a width of 0.53 μm, and a thickness of 0.36 μm.

[0073] Figure 3 This is a TEM image of the prepared nanoporous Silicalite-1 porous material. From... Figure 3 As can be seen, the Silicalite-1 porous material has good particle dispersion, with no adhesion or aggregation between particles, and a particle size range of 96–115 nm.

[0074] Figure 4 The image shows the XRD pattern of the prepared nanoporous Silicalite-1 porous material. Figure 4 As can be seen, the peaks of the prepared Silicalite-1 porous material correspond to those of the simulated Silicalite-1 material, proving that the Silicalite-1 porous material was successfully prepared.

[0075] Figure 5The images show the BET and PSD diagrams of the pore size distribution of the prepared nanoporous Silicalite-1 material. Figure 5 As can be seen from the data, the N2 adsorption-desorption curve of the Silicalite-1 porous material is a type I isotherm, reflecting that the material is a microporous adsorbent with a specific surface area of ​​694.40 m². 2 The pore volume is 0.56 mL / g, and the presence of a hysteresis loop indicates that the gaps between the material particles provide a mesoporous structure. The PSD image shows that the pore size of the Silicalite-1 porous material is 0.71 nm, proving that it possesses nanopore characteristics.

[0076] Example 1

[0077] 1g of nanoporous Silicalite-1 porous material was dispersed in 10g of deionized water and ultrasonically dispersed for 48h until the liquid was homogeneous and transparent. The mixture was then centrifuged at 7200r / min for 2min, discarding large precipitate particles and collecting the supernatant to obtain a 9wt% nanoporous Silicalite-1 water-based porous liquid, denoted as Silicalite-1-PL. 9wt％ .

[0078] The prepared Silicalite-1-PL 9wt％ For isothermal adsorption of methane gas, the isothermal water bath temperature was set to 15℃, and the volume of the adsorption tank was determined using the ideal gas law; 2 mL of Silicalite-1-PL was taken. 9wt％ The gas phase above the liquid surface in the adsorption tank is calculated. Methane gas with a pressure range of 0-9 MPa is introduced into the adsorption tank by stepwise pressurization. The adsorption capacity of Silicalite-1 water-based porous liquid for methane gas is analyzed and calculated by the pressure drop change of the adsorption tank after each stage of pressurization and the corresponding gas state equation.

[0079] Example 2

[0080] 1.5g of nanoporous Silicalite-1 porous material was dispersed in 7g of deionized water and ultrasonically dispersed for 48h until the liquid was homogeneous and transparent. The mixture was then centrifuged at 7200r / min for 2min, discarding large precipitate particles and collecting the supernatant to obtain a 15wt% nanoporous Silicalite-1 water-based porous liquid, denoted as Silicalite-1-PL. 15wt％ .

[0081] Comparative Example 1

[0082] 2g of commercially available pure silica molecular sieve Silicalite-1 was dispersed in 11g of deionized water and ultrasonically dispersed for 48h to prepare a water-based porous liquid with a mass concentration of 15wt%, denoted as Silicalite-1-PL. 15wt％ -1.

[0083] The stability of the water-based porous liquids prepared in Examples 1-2 and Comparative Example 1 was tested, and the test results are as follows: Figure 6 As shown. From Figure 6 As can be seen, after 15 days of standing, Silicalite-1-PL 9wt％ No sedimentation occurred, demonstrating excellent stability. Meanwhile, Silicalite-1-PL prepared from commercially available pure silica molecular sieve Silicalite-1... 15wt％ After standing for 40 hours, the liquid showed obvious stratification. The upper layer gradually became clear, with a large amount of white pure silica molecular sieve Silicalite-1 deposited at the bottom and a small portion suspended in the middle. This is because the particle size of commercially available pure silica molecular sieve Silicalite-1 porous material is nearly 10 times that of the prepared nanoporous Silicalite-1 porous material. Therefore, water-based porous liquids prepared using commercially available pure silica molecular sieve Silicalite-1 porous material are prone to sedimentation and lack good stability. Furthermore, because water-based porous liquids prepared using commercially available pure silica molecular sieve Silicalite-1 porous material do not possess the stability characteristics of porous liquids, they cannot be subjected to methane isothermal adsorption tests, nor can they be applied to the capture and recovery of natural gas.

[0084] The Silicalite-1 water-based porous liquids prepared in Examples 1 and 2 were subjected to methane isothermal adsorption tests. The dissolution effect of deionized water, a sterically hindered solvent, on methane was not excluded. Deionized water was used as a comparative example and denoted as pure water. The results are as follows: Figure 7 As shown. From Figure 7 As can be seen, the adsorption capacity of methane gas by the pure water system is very low in the range of 0–6 MPa because there are no pores in the pure water system. Between 6–9 MPa, the solubility of methane increases with gradually increasing pressure, but the overall methane solubility remains lower than that of the nanoporous Silicalite-1 water-based porous liquid. The adsorption capacity of the nanoporous Silicalite-1 water-based porous liquid for methane gradually increases with increasing pressure. 9wt％ The methane adsorption capacity of Silicalite-1-PL 15wt% is 6 times that of pure water at pressures of 0–2 MPa, and more than 4 times that of pure water at pressures of 2–4 MPa. The methane adsorption capacity of Silicalite-1-PL 15wt% is 8 times that of pure water at pressures of 0–2 MPa, and more than 5 times that of pure water at pressures of 2–4 MPa. Under the same conditions, Silicalite-1-PL...15wt％ The adsorption capacity for methane was significantly higher than that for Silicalite-1-PL. 9wt％ .

[0085] The Silicalite-1 water-based porous liquids prepared in Examples 1 and 2 were subjected to methane isothermal adsorption tests. The dissolution effect of deionized water, the sterically hindered solvent, on methane was removed. The methane adsorption capacity per gram of nanoporous Silicalite-1 porous material was calculated. The nanoporous Silicalite-1 porous material was used as a comparative example and denoted as Silicalite-1. The results are as follows: Figure 8 As shown. From Figure 8 As can be seen, Silicalite-1 does adsorb a higher amount of methane, but the material itself lacks fluidity and cannot be continuously captured and recovered from associated gas in oil fields via pumping. At a pressure of 4–6 MPa, Silicalite-1-PL... 9wt％ With Silicalite-1-PL 15wt％ The adsorption capacity has reached saturation; therefore, the amount of methane stored in the high-pressure section (6–9 MPa) is mainly reflected by the dissolution of methane in the solvent water due to pressure (e.g., ...). Figure 7 (As shown in the high-pressure section of the pure water curve), Silicalite-1-PL 9wt％ With Silicalite-1-PL 15wt％ The adsorption capacity for methane is 70-80% of that of Silicalite-1, proving that Silicalite-1-PL... 9wt％ With Silicalite-1-PL 15wt％ It is porous and has good adsorption properties for methane.

[0086] 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 nanoporous Silicalite-1 water-based porous liquid, characterized in that, Includes the following steps: Spherical nanoporous Silicalite-1 was mixed with a sterically hindered solvent, sonicated, and then centrifuged to obtain a water-based porous liquid containing the nanoporous Silicalite-1. The steric solvent is water; The spherical nanoporous Silicalite-1 has a particle size of 96~115nm and a pore size of 0.7~0.8nm; The specific surface area of ​​the spherical nanoporous Silicalite-1 is 680~700 m². 2 / g, pore volume is 0.45~0.65mL / g; The mass ratio of the spherical nanopore Silicalite-1 to the steric hindrance solvent is 1:5~12; The duration of the ultrasound is 36-50 hours, the centrifugation speed is 6000-8000 r / min, the centrifugation time is 1-3 minutes, and the number of centrifugations is 1-3 times.

2. The preparation method according to claim 1, characterized in that, The preparation method of the spherical nanopore Silicalite-1 includes the following steps: A hydrolysis-condensation reaction was carried out by adding tetraethyl silicate to an aqueous solution of tetrapropylammonium hydroxide to obtain a homogeneous mixture; the homogeneous mixture was subjected to a hydrothermal reaction to obtain a nanoporous Silicalite-1 precursor; the nanoporous Silicalite-1 precursor was calcined to obtain spherical nanoporous Silicalite-1. The amount of tetraethyl silicate used is based on the molar amounts of silicon dioxide and ethanol produced after its hydrolysis and condensation reaction. In the homogeneous mixture, the molar ratio of tetrapropylammonium hydroxide, silicon dioxide and ethanol is 4~5:12~13:48~52. The mass concentration of tetrapropylammonium hydroxide in the aqueous solution is 35-45 wt%.

3. The preparation method according to claim 2, characterized in that, The hydrothermal reaction is carried out at a temperature of 85-95℃ for a duration of 40-55 hours.

4. The preparation method according to claim 2, characterized in that, The calcination temperature is 520~580℃, and the time is 9~12h; The calcination atmosphere is an air atmosphere.

5. The preparation method according to claim 2 or 4, characterized in that, The process before calcination also includes drying the nanoporous Silicalite-1 precursor at a temperature of 190-210°C for 1-1.75 hours.

6. The preparation method according to claim 1, characterized in that, The duration of the ultrasound is 36-50 hours.

7. The application of the nanoporous Silicalite-1 water-based porous liquid prepared by the preparation method according to any one of claims 1 to 6 in the capture and recovery of natural gas.

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