A system and method for screening ionic liquids for the preparation of CH4 / N2 separation membranes

Abstract

This invention proposes an ionic liquid screening method for preparing CH4 / N2 separation membranes, belonging to the field of materials technology. The method includes the following steps: determining the initial structure of the ionic liquid, determining the stable structure of the dimer, and calculating the dimer binding energy. This invention is based on density functional theory (DFT) simulations, grounded in the Schrödinger equation, which is theoretically sound and yields highly reliable calculation results. It can quickly screen ionic liquids with differential binding properties for CH4 and N2. The ionic liquid blend membranes prepared from the screened ionic liquids exhibit a promoted transport mechanism, demonstrating excellent CH4 / N2 selectivity and significantly improving the CH4 / N2 separation selectivity of the polymer membrane. It also enhances CH4 permeability to a certain extent.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to an ionic liquid screening system and method for preparing CH4 / N2 separation membranes. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Currently, gas separation membranes can be mainly classified into three categories: polymer membranes, inorganic membranes, and mixed matrix membranes. Among them, polymers have become the most widely used and researched membrane separation material due to their low price, excellent processing performance, and superior overall performance. However, there is a trade-off relationship between the gas permeability and selectivity of polymer membranes, ultimately limiting their separation performance and restricting their further development and application. Utilizing the high solubility and transport-enhancing properties of ionic liquids for gas molecules and blending them with polymers is an effective way to overcome the trade-off relationship. However, CH4 and N2 have extremely similar physicochemical properties, and there are many types of ionic liquids. How to screen suitable ionic liquids to prepare blended membranes has become a significant challenge. Therefore, developing a low-cost and high-efficiency ionic liquid screening method for CH4 / N2 separation, and then preparing polymer-ionic liquid blended membranes with excellent CH4 / N2 selectivity and CH4 permeability, is of great significance for controlling methane emissions from the oil and gas industry, achieving methane emission reduction, and mitigating global warming. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention provides an ionic liquid screening system and method for preparing CH4 / N2 separation membranes. The system and method provided by this invention can rapidly screen ionic liquids with differential binding properties to CH4 and N2.

[0005] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, an ionic liquid screening method for preparing CH4 / N2 separation membranes includes the following steps:

[0007] (1) Determination of the initial structure of ionic liquid: Geometric optimization of anions and cations in candidate ionic liquids is carried out, the single-point energy of the optimized stable structure is calculated, and the wave function is obtained; the wave function is analyzed, the electrostatic potential distribution of anions and cations is calculated, the relative orientation of anions and cations constituting the ionic liquid is determined, and the initial structure of ionic liquid is obtained.

[0008] (2) Determination of stable dimer structure: Geometric optimization is carried out on the initial structure of the ionic liquid, the single-point energy of the optimized stable structure is calculated, and the wave function is obtained; the wave function is analyzed, the global minimum value of electrostatic potential is calculated, the initial structure of ionic liquid-CH4 dimer and ionic liquid-N2 dimer is determined, and a stable dimer structure is obtained after geometric optimization;

[0009] (3) Calculation of dimer binding energy: Calculate the dimer binding energy of the stable dimer structure obtained in step (2) and compare the difference in binding energy.

[0010] A further technical solution is that the ionic liquid screening method for preparing CH4 / N2 separation membrane further includes preparing a polymer-ionic liquid blend membrane based on the ionic liquid screened in step (3) and testing the CH4 / N2 separation performance.

[0011] Preferably, the polymer is a styrene-ethylene-butene-styrene block copolymer (SEBS), and the solvent used in preparing the polymer-ionic liquid blend membrane is toluene.

[0012] In a further technical solution, in step (1), both geometric optimization and single-point energy calculation are carried out based on Gaussian software.

[0013] Preferably, the geometry optimization uses B3LYP as the functional, 6-311G** as the cation basis, and 6-311+G** as the anion basis.

[0014] Preferably, the functional used for single-point energy calculation is B3LYP, and the basis set is ma-TZVPP.

[0015] In a further technical solution, step (1) involves analyzing the wave function by using Multiwfn software.

[0016] In a further technical solution, in step (2), the initial structure geometry optimization of the ionic liquid uses the functional B3LYP and the basis set 6-311+G**; the single-point energy calculation uses the functional B3LYP and the basis set ma-TZVPP.

[0017] In a further technical solution, step (2) involves analyzing the wave function by using Multiwfn software.

[0018] In a further technical solution, in step (2), the initial structure geometry optimization of the dimer uses the functional B3LYP and the basis set 6-311+G**.

[0019] In a further technical solution, in step (3), the dimer binding energy is calculated based on ORCA software.

[0020] Preferably, the dimer binding energy calculation uses the DLPNO-CCSD(T) method combined with tightPNO precision, along with a hybrid basis set.

[0021] More preferably, the method for applying the mixed basis set is as follows: defining a base set centered on the C atom of CH4 or the N atom of N2. The range is a weak interaction region. The aug-cc-pVQZ basis set is applied to non-hydrogen atoms within the weak interaction region, the cc-pVTZ basis set is applied to hydrogen atoms, and the cc-pVDZ basis set is applied to atoms outside the weak interaction region.

[0022] Secondly, an ionic liquid screening system for preparing CH4 / N2 separation membranes includes:

[0023] The initial structure determination module is configured to: perform geometric optimization on the anions and cations in the candidate ionic liquid, calculate the single-point energy of the optimized stable structure, and obtain the wave function; analyze the wave function, calculate the electrostatic potential distribution on the anion and cation surfaces, determine the relative orientation of the anions and cations that make up the ionic liquid, and obtain the initial structure of the ionic liquid;

[0024] The stable structure determination module is configured to: perform geometric optimization on the initial structure of the ionic liquid, calculate the single-point energy of the optimized stable structure, and obtain the wave function; analyze the wave function, calculate the global minimum of the electrostatic potential, determine the initial structures of the ionic liquid-CH4 dimer and the ionic liquid-N2 dimer, and obtain a stable dimer structure after geometric optimization;

[0025] The binding energy calculation module is configured to calculate the dimer binding energy for a stable dimer structure and compare the differences in binding energy.

[0026] A further technical solution involves calculating the binding energy of dimers using ORCA software within the binding energy calculation module.

[0027] Preferably, the dimer binding energy calculation uses the DLPNO-CCSD(T) method combined with tightPNO precision, along with a hybrid basis set.

[0028] More preferably, the method for applying the mixed basis set is as follows: defining a base set centered on the C atom of CH4 or the N atom of N2. The range is a weak interaction region. The aug-cc-pVQZ basis set is applied to non-hydrogen atoms within the weak interaction region, the cc-pVTZ basis set is applied to hydrogen atoms, and the cc-pVDZ basis set is applied to atoms outside the weak interaction region.

[0029] Thirdly, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the above-described method.

[0030] Fourthly, a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps of the above-described method.

[0031] The above one or more technical solutions have the following beneficial effects:

[0032] The present invention discloses an ionic liquid screening system and method for preparing CH4 / N2 separation membranes. Based on density functional theory (DFT) simulation and the Schrödinger equation, the system is theoretically sound and the calculation results are highly reliable. It can quickly screen out ionic liquids with different binding properties to CH4 and N2.

[0033] The ionic liquids screened in this invention exhibit differential binding properties for CH4 and N2. Based on these, ionic liquid blend membranes for CH4 / N2 separation were prepared, which showed a promoted transport mechanism and excellent CH4 / N2 selectivity. This greatly improved the CH4 / N2 separation selectivity of the polymer membrane and also enhanced the CH4 permeability to a certain extent.

[0034] This invention addresses the specific computational process for screening ionic liquids by employing appropriate functionals and basis sets, thereby reducing time costs and improving efficiency while ensuring computational accuracy.

[0035] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] Figure 1 The structural formulas of the anions and cations in the examples are shown below;

[0038] Figure 2 This is a diagram showing the surface electrostatic potential distribution of anions and cations in the embodiment;

[0039] Figure 3 This is a distribution diagram of the global minimum points of the electrostatic potential of the ionic liquid in the examples;

[0040] Figure 4 The diagram shows the IMH analysis of the dimer in this example, where ... H ... O Ⅰ distance: CH···O Ⅰ Included angle: 171.24°;

[0041] Figure 5 The diagram shows the IMH analysis of the dimer in this example, where ... N Ⅰ ···O Ⅰ distance: ·····N Ⅱ ···O Ⅰ distance:

[0042] Figure 6 The diagram shows the IMH analysis of the dimer in this example, where ... H ... O Ⅱ distance: CH···O Ⅱ Included angle: 166.63°;

[0043] Figure 7 The diagram shows the IMH analysis of the dimer in this example, where ... N Ⅰ ···O Ⅱ distance: ·····N Ⅱ ···O Ⅱ distance:

[0044] Figure 8 The diagram shows the electron density distribution of the dimer in the example, where CH4 and O... Ⅰ The electron clouds of atoms overlap, forming weak hydrogen bonds CH···O;

[0045] Figure 9 The diagram shows the electron density distribution of the dimer in the example, where N2 and O... Ⅰ The atoms did not experience electron cloud overlap;

[0046] Figure 10 The diagram shows the electron density distribution of the dimer in this example, where CH4 displaces the long carbon chain and moves towards O. Ⅱ Atoms approaching each other;

[0047] Figure 11 The diagram shows the electron density distribution of the dimer in this embodiment, where N2 is completely blocked from the long carbon chain and cannot approach O. Ⅱ atom;

[0048] Figure 12This is a comparison chart of the CH4 / N2 separation performance of the blend membrane and the polymer membrane in the upper limit of Robeson's method in the examples. Detailed Implementation

[0049] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0051] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0052] Example 1

[0053] This embodiment discloses a method for preparing CH4 / N2 separation membranes using ionic liquid screening, comprising the following steps:

[0054] (1) Initial structure of the ionic liquid determined: Trihexyl(tetradecyl)phosphine bis(2,4,4-trimethylpentyl)phosphonate ([P (14)666 [TMPP]) is used as an ionic liquid. The geometry optimization and single-point energy calculations involved were performed using Gaussian software. The B3LYP functional was employed, combined with DFT-D3(BJ) dispersion correction, to optimize the [P] cation. (14)666 ] + and anions [TMPP] - Geometric optimization is performed, where the cation [P] (14)666 ] + The optimization employs the 6-311G** basis set, anion [TMPP]. - The optimization adopted the 6-311+G** basis set considering dispersion effects; the B3LYP functional and the ma-TZVPP basis set were used to perform single-point energy calculations on the geometrically optimized stable structure to obtain the wavefunction; the Multiwfn software was used to analyze the wavefunction, and the electrostatic potential distribution maps of the anion and cation surfaces were plotted respectively. Based on the principle of electrostatic potential complementarity, the negative electrostatic potential region of the anion surface was oriented towards the positive electrostatic potential region of the cation surface to obtain [P]. (14)666 [TMPP] Initial structure.

[0055] (2) [P (14)666 The stable structure of the [TMPP]-CH4(N2) dimer was determined: using the B3LYP functional and the 6-311+G** basis set, combined with DFT-D3(BJ) dispersion correction, the [P]-CH4(N2) dimer structure was determined. (14)666A stable structure was obtained by geometric optimization of the initial structure [TMPP]; the B3LYP functional and the ma-TZVPP basis set were used to optimize [P] (14)666 [TMPP] Single-point energy calculations were performed on the stable structure to obtain the wavefunction; the wavefunction was analyzed using Multiwfn software to calculate the magnitude and spatial coordinates of the global minimum point of electrostatic potential, and the corresponding distribution map of the electrostatic potential minimum point was plotted; CH4 and N2 molecules were placed in [P (14)666 [TMPP] Near the point of minimum electrostatic potential, [P] is obtained (14)666 The initial structure of the [TMPP]-CH4(N2) dimer was determined using a B3LYP functional and a 6-311+G** basis set, combined with DFT-D3(BJ) dispersion correction. (14)666 A stable structure was obtained by geometrically optimizing the initial structure of the [TMPP]-CH4(N2) dimer.

[0056] (3) [P] (14)666 Calculation of binding energy of [TMPP]-CH4(N2) dimer: [P (14)666 The binding energy of the [TMPP]-CH4(N2) dimer was calculated using ORCA software, employing the DLPNO-CCSD(T) method combined with tightPNO precision. [P] (14)666 [TMPP]-CH4 dimer applies a mixed basis set: defined with the C atom of CH4 as the center. The region is a weakly interacting region. Aug-cc-pVQZ basis sets are applied to non-hydrogen atoms within this region, and cc-pVTZ basis sets are applied to hydrogen atoms. For atoms outside the weakly interacting region, cc-pVDZ basis sets are applied. Auxiliary basis sets are automatically constructed for the applied mixed basis sets. RI-JK techniques are used to accelerate the exchange and coulomb part calculations. The counterpoise method is used to correct basis set overlap error (BSSE). The calculated [P] (14)666 The binding energies of the [TMPP]-CH4 dimer at the two global minimum electrostatic potential sites are -16.75 kJ / mol. -1 and -16.00 kJ mol -1 , corresponding to [P (14)666 The binding energy of the [TMPP]-N2 dimer is -14.27 kJ / mol. -1 and -7.21kJ mol -1 .

[0057] (4) SEBS-[P (14)666 Preparation and testing of [TMPP] blend membrane: 0.5g [P] (14)666[TMPP] and 2.0 g of SEBS polymer were dissolved in 11.33 g of toluene solution and stirred until a clear casting solution was obtained. The solution was then coated on a coating machine. The coated membrane was allowed to stand at room temperature for 24 h and then placed in a vacuum drying oven for 48 h. The CH4 and N2 permeability coefficients of the prepared blend membrane were tested using a differential pressure gas permeation analyzer, and the CH4 / N2 selectivity was calculated.

[0058] from Figure 1 It can be seen that, [P] (14)666 The chemical formula of [TMPP] is C 48 H 102 O2P2.

[0059] from Figure 2 It can be seen that the cation [P] (14)666 ] + The region of positive surface electrostatic potential is concentrated near the P atom, and the anion [TMPP] - The negative electrostatic potential region on the surface is concentrated near the O atoms.

[0060] from Figure 3 It can be seen that, [P] (14)666 The global minimum of the electrostatic potential of [TMPP] is located near two O atoms, with magnitudes of -75.48 kcal mol. -1 and -68.20 kcal mol -1 .

[0061] from Figure 4-7 It can be seen that, [P] (14)666 [TMPP] The exposed O atom sites form weak hydrogen bonds with CH4.

[0062] from Figure 8-11 It can be seen that, compared to CH4, [P (14)666 The steric hindrance effect of the carbon chain above the concealed O atom site on N2 is more pronounced, which is the main reason for the large difference in binding energy between CH4 and N2 at this site.

[0063] from Figure 12 It can be seen that the CH4 / N2 separation performance of the polymer-ionic liquid blend membrane designed by this method far exceeds the Robeson upper limit.

[0064] Example 2

[0065] An ionic liquid screening system for preparing CH4 / N2 separation membranes, comprising:

[0066] The initial structure determination module is configured to: perform geometric optimization on the anions and cations in the candidate ionic liquid, calculate the single-point energy of the optimized stable structure, and obtain the wave function; analyze the wave function, calculate the electrostatic potential distribution on the anion and cation surfaces, determine the relative orientation of the anions and cations that make up the ionic liquid, and obtain the initial structure of the ionic liquid.

[0067] The stable structure determination module is configured to: perform geometric optimization on the initial structure of the ionic liquid, calculate the single-point energy of the optimized stable structure, and obtain the wave function; analyze the wave function, calculate the global minimum of the electrostatic potential, determine the initial structures of the ionic liquid-CH4 dimer and the ionic liquid-N2 dimer, and obtain a stable dimer structure after geometric optimization.

[0068] The binding energy calculation module is configured to calculate the dimer binding energy for a stable dimer structure and compare the differences in binding energy.

[0069] In the binding energy calculation module, the dimer binding energy calculation is based on ORCA software.

[0070] Dimer binding energy was calculated using the DLPNO-CCSD(T) method with tightPNO precision, combined with a hybrid basis set.

[0071] The method for applying mixed basis sets is as follows: Centered on the C atom of CH4 or the N atom of N2, define... The range is a weak interaction region. The aug-cc-pVQZ basis set is applied to non-hydrogen atoms within the weak interaction region, the cc-pVTZ basis set is applied to hydrogen atoms, and the cc-pVDZ basis set is applied to atoms outside the weak interaction region.

[0072] Example 3

[0073] The purpose of this embodiment is to provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the above-described method.

[0074] Example 4

[0075] The purpose of this embodiment is to provide a computer-readable storage medium.

[0076] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps of the above method.

[0077] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0078] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0079] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing CH4 / N2 separation membranes using ionic liquid screening, characterized in that, Includes the following steps: (1) Determination of the initial structure of the ionic liquid: Geometric optimization of the anions and cations in the trihexyl(tetradecyl)phosphine bis(2,4,4-trimethylpentyl)phosphate ionic liquid was carried out, the single-point energy of the optimized stable structure was calculated, and the wave function was obtained; the wave function was analyzed, the electrostatic potential distribution of the anions and cations was calculated, the relative orientation of the anions and cations constituting the ionic liquid was determined, and the initial structure of the ionic liquid was obtained. (2) Determination of stable dimer structure: Geometric optimization is carried out on the initial structure of the ionic liquid, the single-point energy of the optimized stable structure is calculated, and the wave function is obtained; the wave function is analyzed, the global minimum value of electrostatic potential is calculated, the initial structure of ionic liquid-CH4 dimer and ionic liquid-N2 dimer is determined, and a stable dimer structure is obtained after geometric optimization; (3) Calculation of dimer binding energy: Calculate the dimer binding energy of the stable dimer structure obtained in step (2) and compare the difference in binding energy; In step (1), the geometric optimization and single-point energy calculation are both carried out using Gaussian software. The wave function is analyzed using the Multiwfn software.

2. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 1, characterized in that, It also includes preparing a polymer-ionic liquid blend membrane based on the ionic liquid screened in step (3) and testing the CH4 / N2 separation performance.

3. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 2, characterized in that, The polymer is a styrene-ethylene-butene-styrene block copolymer (SEBS), and the solvent used in preparing the polymer-ionic liquid blend membrane is toluene.

4. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 1, characterized in that, The geometry optimization used B3LYP as the functional, 6-311G** as the cation basis set, and 6-311+G** as the anion basis set.

5. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 1, characterized in that, The functional used for single-point energy calculation is B3LYP, and the basis set is ma-TZVPP.

6. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 1, characterized in that, In step (2), the initial structure geometry optimization of the ionic liquid uses the functional B3LYP and the basis set of the anion is 6-311+G**; the single-point energy calculation uses the functional B3LYP and the basis set is ma-TZVPP. The wave function is analyzed using the Multiwfn software. The initial structure geometry optimization of the dimer uses B3LYP as the functional and 6-311+G** as the anionic basis set.

7. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 1, characterized in that, In step (3), the dimer binding energy is calculated based on ORCA software.

8. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 7, characterized in that, The dimer binding energy was calculated using the DLPNO-CCSD(T) method combined with tightPNO precision, along with a hybrid basis set.

9. The ionic liquid screening method for preparing CH4 / N2 separation membranes according to claim 8, characterized in that, The method for applying the mixed basis sets is as follows: a weak interaction region is defined within a 5 Å range, centered on the C atom of CH4 or the N atom of N2. The aug-cc-pVQZ basis set is applied to non-hydrogen atoms within the weak interaction region, the cc-pVTZ basis set is applied to hydrogen atoms, and the cc-pVDZ basis set is applied to atoms outside the weak interaction region.

10. An ionic liquid screening system for preparing CH4 / N2 separation membranes, characterized by, include: The initial structure determination module is configured to: perform geometric optimization on the anions and cations in the trihexyl(tetradecyl)phosphine bis(2,4,4-trimethylpentyl)phosphonate ionic liquid, calculate the single-point energy of the optimized stable structure, and obtain the wave function; analyze the wave function, calculate the surface electrostatic potential distribution of the anions and cations, determine the relative orientation of the anions and cations that make up the ionic liquid, and obtain the initial structure of the ionic liquid; The stable structure determination module is configured to: perform geometric optimization on the initial structure of the ionic liquid, calculate the single-point energy of the optimized stable structure, and obtain the wave function; analyze the wave function, calculate the global minimum of the electrostatic potential, determine the initial structures of the ionic liquid-CH4 dimer and the ionic liquid-N2 dimer, and obtain a stable dimer structure after geometric optimization; The binding energy calculation module is configured to calculate the dimer binding energy for a stable dimer structure and compare the differences in binding energy. The geometric optimization and single-point energy calculation were both carried out using Gaussian software. The wave function is analyzed using the Multiwfn software.

11. The system for screening ionic liquids for CH4 / N2 separation membranes according to claim 10, wherein, In the binding energy calculation module, the dimer binding energy calculation is based on ORCA software.

12. The ion liquid screening system for preparing CH4 / N2 separation membranes according to claim 11, characterized in that, The dimer binding energy was calculated using the DLPNO-CCSD(T) method with tightPNO precision, combined with a hybrid basis set.

13. The ionic liquid screening system for preparing CH4 / N2 separation membranes according to claim 12, characterized in that, The method for applying the mixed basis sets is as follows: a weak interaction region is defined within a 5 Å range, centered on the C atom of CH4 or the N atom of N2. The aug-cc-pVQZ basis set is applied to non-hydrogen atoms within the weak interaction region, the cc-pVTZ basis set is applied to hydrogen atoms, and the cc-pVDZ basis set is applied to atoms outside the weak interaction region.

14. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method according to any one of claims 1-9.

15. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, performs the steps of the method described in any one of claims 1-9.

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