Application of porous catechu[9] aromatic materials in alkane adsorption and separation

Abstract

This invention discloses the application of a porous catechu[9] aromatic material in the adsorption and separation of alkane. The porous catechu[9] aromatic material has the following chemical structure: the alkane is one or more combinations of methane, ethane, and propane. The separation process of this invention is simple to operate and has low equipment requirements; the separation process does not require distillation, resulting in low energy consumption, energy saving, and reduced natural gas costs; the material used is self-healing and can extend its service life; the material used has extremely high hydrophobicity and maintains almost the same working performance under dry conditions at 97% relative humidity.

Description

Technical Field

[0001] This invention relates to the field of alkane adsorption and separation technology, specifically to the application of a porous catechu[9] aromatic material in alkane adsorption and separation. Background Technology

[0002] Natural gas is an extremely important clean fuel that helps alleviate the energy crisis caused by rapid global population growth and high productivity. Methane is the main component of natural gas, with an energy density as high as 55.5 MJ·kg⁻¹. -1 However, the complex composition of natural gas in different countries and regions often results in lower quality. In conventional natural gas fields, methane typically accounts for 85%, ethane 10%, and propane 5%. Purifying methane from natural gas can not only increase its calorific value but also recover high-value ethane and propane, thus upgrading the energy structure. Traditional cryogenic distillation technologies are often energy-intensive, require sophisticated equipment, and cause severe environmental pollution; therefore, it is necessary to develop novel, environmentally friendly, and easy-to-operate adsorption separation methods.

[0003] Water vapor, a common impurity in oilfield gas, is inevitably present in natural gas pipelines, posing a significant hazard. Water vapor can not only compete with adsorbents for adsorption sites, leading to a marked decline in performance, but it can also replace ligands in the framework material, causing framework collapse. Therefore, when applying adsorption separation technology in practice, two factors must be considered: first, the adsorbent itself must be stable against water vapor and not be degraded; second, it must adsorb as little water vapor as possible under high humidity conditions to ensure excellent performance in actual industrial production.

[0004] Self-healing significantly extends the service life of materials, which is one of their most attractive properties. Solid adsorbents used in pipeline systems, due to their poor flowability, cannot be directly replaced after damage, greatly complicating the operational process. A paradox arises: damage to traditional porous materials such as zeolites and molecular sieves is often irreversible; the repair of metal-organic frameworks often relies on energy-intensive solvothermal reactions; and the reconstruction of molecular porous materials typically requires a cumbersome recrystallization process with precisely controlled crystallization conditions to achieve ideal polymorphism. This is undoubtedly unsuitable for practical applications, complicating the operational process and increasing usage costs. Therefore, achieving self-healing of porous materials simply under mild conditions is a crucial and urgent problem to be solved.

[0005] The patent specification with publication number CN 116284823 A discloses a novel static porous material that can be used for the separation of methane / ethane / propane in shale gas, but no gas dynamic breakthrough experiment was conducted, so it is impossible to verify its practical application.

[0006] The patent specification with publication number CN 105524083 A discloses a method for purifying natural gas using water-stable metal-organic framework materials, but it does not provide actual verification of the separation effect under high humidity conditions. Summary of the Invention

[0007] In a first aspect, the present invention provides an application of a porous catechu[9] aromatic material in the adsorption and separation of alkane, wherein the porous catechu[9] aromatic material has the following chemical structure:

[0008]

[0009] The alkane is one or more combinations of methane, ethane, and propane.

[0010] In the first aspect of the application, the porous catechu[9] aromatic material can be activated or self-repaired before being used for alkane adsorption and separation. Wherein:

[0011] The activation may include: fumigating freshly prepared catechu[9] aromatics with n-pentane and / or n-hexane vapors, and heating at 60-90°C after fumigation to obtain the porous catechu[9] aromatics material.

[0012] The self-healing process may include fumigating the structurally collapsed non-porous catechin[9] aromatic material with n-pentane and / or n-hexane vapors to obtain the porous catechin[9] aromatic material.

[0013] Furthermore, the fumigation time can be 12 to 24 hours; the heating time can be 12 to 24 hours.

[0014] Secondly, the present invention provides an application of a porous catechu[9] aromatic material as an adsorbent for natural gas purification, wherein the porous catechu[9] aromatic material has the following chemical structure:

[0015]

[0016] In the second aspect of the application, the porous catechu[9] aromatic material can be activated or self-repaired before being used for natural gas purification. Wherein:

[0017] The activation may include: fumigating the freshly prepared catechu[9] aromatics with n-pentane and / or n-hexane vapors, and heating the fumigated material at 60-90°C to obtain the porous catechu[9] aromatics material.

[0018] The self-healing process may include fumigating the structurally collapsed non-porous catechin[9] aromatic material with n-pentane and / or n-hexane vapors to obtain the porous catechin[9] aromatic material.

[0019] Furthermore, the fumigation time can be 12 to 24 hours; the heating time can be 12 to 24 hours.

[0020] Thirdly, the present invention provides a method for adsorbing and separating methane and C2 / C3 alkanes, using porous catechu[9] aromatic material as an adsorbent, contacting a mixture containing methane and C2 / C3 alkanes with the adsorbent, wherein the adsorbent selectively and preferentially adsorbs C2 / C3 alkanes to achieve methane purification;

[0021] The porous catechin[9] aromatic material has the following chemical structure:

[0022]

[0023] The C2 / C3 alkane is at least one of ethane and propane.

[0024] The method described in the third aspect, wherein the porous catechu[9] aromatic material can be activated or self-healed before contacting the mixture. Wherein:

[0025] The activation may include: fumigating the freshly prepared catechu[9] aromatics with n-pentane and / or n-hexane vapors, and heating the fumigated material at 60-90°C to obtain the porous catechu[9] aromatics material.

[0026] The self-healing process may include fumigating the structurally collapsed non-porous catechin[9] aromatic material with n-pentane and / or n-hexane vapors to obtain the porous catechin[9] aromatic material.

[0027] Furthermore, the fumigation time can be 12 to 24 hours; the heating time can be 12 to 24 hours.

[0028] In the third aspect of the method, the molar percentage of methane in the mixture can be 50-99%.

[0029] The method described in the third aspect may further contain water in the mixture.

[0030] The method described in the third aspect may have a mixture in gaseous form, wherein the water may be water vapor.

[0031] The porous catechin[9] aromatic material described in this invention is existing technology. It can be obtained by activating catechin[9] aromatics. For specific preparation methods, please refer to the patent specification with publication number CN115337913A, etc.

[0032] The porous catechu[9] aromatic material has a one-dimensional hexagonal channel structure with periodic neck channels, and the narrowest part of the channel has a dimension of

[0033] Due to the differences in molecular structure and size among methane, ethane, and propane, the porous catechu[9] aromatic material can selectively and preferentially capture ethane and propane, thereby achieving the purification of natural gas (methane).

[0034] The inventors discovered that the porous catechu[9] aromatic material possesses self-healing ability and good hydrophobicity, with a room temperature water absorption of only 7.5 mg / g at 100% relative humidity. This porous catechu[9] aromatic material can purify methane at relative humidity up to 97%, for example, it can selectively adsorb C2 / C3 alkanes in a mixture containing methane and C2 / C3 alkanes at 97% relative humidity, thereby achieving methane purification.

[0035] This invention can solve the defects in the natural gas purification process, such as complex operation, high labor costs, and high energy consumption, and has the advantages of low energy consumption, simple process, and adaptability to complex environments.

[0036] Compared with the prior art, the present invention has the following advantages: the separation process is simple to operate and has low equipment requirements; the separation process does not require distillation, resulting in low energy consumption, energy saving, and reduced natural gas costs; the materials used are self-healing and can extend their service life; the materials used have extremely high hydrophobicity and maintain almost the same working performance under dry conditions at 97% relative humidity. Attached Figure Description

[0037] Figure 1 The porous catechu[9] aromatic material CaC9 of Example 1 open Powder X-ray diffraction (PXRD) pattern.

[0038] Figure 2 The porous catechu[9] aromatic material CaC9 of Example 1 open A schematic diagram of the single crystal structure.

[0039] Figure 3 The porous catechu[9] aromatic material CaC9 of Example 2 open PXRD spectra of self-healing and cycling experiments;

[0040] Figure 4 The porous catechu[9] aromatic material CaC9 of Example 3 open Experimental graph of water vapor adsorption-desorption curve at 298K.

[0041] Figure 5 The porous catechu[9] aromatic material CaC9 of Example 4 open Adsorption-desorption curves of methane, ethane and propane at 273 K.

[0042] Figure 6 The porous catechu[9] aromatic material CaC9 of Example 4open Adsorption-desorption curves of methane, ethane and propane at 298 K.

[0043] Figure 7 For equimolar ethane / methane and propane / methane ratios, the porous catechu[9] aromatic material CaC9 is calculated based on the ideal adsorption solution theory. open Adsorption selectivity at 298K.

[0044] Figure 8 For methane, ethane, and propane, based on the virial equation, porous catechu[9] aromatic materials CaC9 open Adsorption enthalpy results at 298K.

[0045] Figure 9 The porous catechu[9] aromatic material CaC9 of Example 5 open The actual penetration curve obtained under dry conditions.

[0046] Figure 10 The porous catechu[9] aromatic material CaC9 of Example 5 open The actual penetration curve obtained under 97% relative humidity conditions. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0048] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer.

[0049] Example 1

[0050] Preparation of porous catechu[9] aromatic material: Weigh 2g of catechu[9] aromatic material and place it in an open glass bottle. Place the device in a saturated n-hexane vapor environment overnight. After 24 hours, take it out and dry it under vacuum at 80℃ to obtain porous catechu[9] aromatic material, denoted as CaC9. open .

[0051] The characterization data of the product prepared in this embodiment are as follows:

[0052] CaC9 open , 1 H NMR (600MHz, CDCl3, 298K): δ3.83(s,18H),3.27(s,54H),2.74(s,36H),1.87(s,18H).

[0053] 13C NMR (600MHz, CDCl3, 298K): δ150.3,138.8,128.7,59.4,31.6,24.9.

[0054] PXRD test results are as follows Figure 1 As shown, the obtained porous catechu[9] aromatic material has good crystallinity.

[0055] The 77K nitrogen adsorption-desorption curve results showed that the obtained porous catechu[9] aromatics were 370m in size according to Multi-Point BET calculation. 2 / g.

[0056] CaC9 open single crystal structure such as Figure 2 As shown, CaC9 forms a one-dimensional hexagonal channel, with the narrowest point being approximately...

[0057] Example 2

[0058] Fatigue caused by prolonged use of adsorbents in complex real-world environments can lead to the continued spread and expansion of minute damage, eventually causing the material to collapse into a dense, non-porous structure. This embodiment investigates the self-healing properties of the material.

[0059] The porous catechu[9] aromatic material of Example 1 can be dissolved in dichloromethane and recovered by rotary evaporation, but the porous structure is destroyed at this time. The damaged catechu[9] aromatic material was placed in a hexane saturated vapor environment for about 24 hours, and its structure was repaired.

[0060] PXRD results are as follows Figure 3 As shown, the damaged catechin[9]arene underwent significant structural changes and exhibited poor crystallinity. However, after repair, the catechin[9]arene reverted to its initial porous structure.

[0061] like Figure 3 As shown, this repair process can be easily repeated at least five times without any change in crystal structure, demonstrating the material's superior cycle life.

[0062] Example 3

[0063] The CaC9 of Example 1 was tested at 298 K using a specific surface area and porosity analyzer. open Adsorption of water vapor, such as Figure 4 As shown, the results indicate that the adsorption capacity at 100% relative humidity is 7.5 mg / g, suggesting that CaC9 open It belongs to the category of hydrophobic materials.

[0064] Example 4

[0065] The CaC9 of Example 1 was tested at 273 K and 298 K using a specific surface area and porosity analyzer. open Adsorption of methane, ethane, and propane, such as Figure 5 As shown, the results indicate that under conditions of 273 K and 1 atmosphere, CaC9 open The adsorption capacity for methane, ethane, and propane is 7.55 cm⁻¹. 3 / g, 23.33cm 3 / g and 32.26cm 3 / g. For example... Figure 6 As shown, the results indicate that under conditions of 298 K and 1 atmosphere, CaC9 open The adsorption capacity for methane, ethane, and propane is 4.46 cm⁻¹. 3 / g, 18.02cm 3 / g and 26.42cm 3 / g. CaC9 open It exhibits significant adsorption of ethane and propane, but very low adsorption of methane.

[0066] Based on the ideal adsorption solution theory, the selectivity of ethane / methane at 298 K is calculated to be 15, and the selectivity of propane / methane is calculated to be 353. Figure 7 As shown.

[0067] CaC9 was calculated based on the virial equation. open The adsorption enthalpy for methane, ethane, and propane, such as Figure 8 As shown, the adsorption enthalpies are 31.3 kJ / mol, 22.6 kJ / mol, and 21.2 kJ / mol, respectively. The low adsorption enthalpy indicates that the adsorbate can be desorbed quickly, achieving rapid regeneration.

[0068] Example 5

[0069] In a gas dynamic penetration experimental setup, the CaC9 of Example 1 was tested under dry conditions. open The purification effect on the mixed gas (methane / ethane / propane = 85 / 10 / 5, molar ratio), such as Figure 9 As shown, CaC9 open It can achieve one-step purification of methane.

[0070] In a gas dynamic penetration test apparatus, the CaC9 of Example 1 was tested under 97% relative humidity. open The purification effect on the mixed gas (methane / ethane / propane = 85 / 10 / 5, molar ratio), such as Figure 10 As shown, CaC9 open It exhibits the same purification effect as under dry conditions, and the breakthrough curves of three replicates almost completely overlap, proving that CaC9... openIt exhibits almost no decrease in performance and good cycling capability at 97% relative humidity.

[0071] In summary, the porous catechu[9] aromatic material of the present invention can be used for adsorption and capture of any one of methane, ethane and propane, as well as adsorption, separation and purification of any two or more of them. It can also be reused in a high humidity environment and has a simple self-healing operation.

[0072] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. An application of a porous catechu[9] aromatic material in the adsorption and separation of alkane, characterized in that, The porous catechin[9] aromatic material has the following chemical structure: ； The alkane is methane and ethane, or methane and propane.

2. The application according to claim 1, characterized in that, The porous catechu[9] aromatic material is activated or self-repaired before being used for alkane adsorption and separation. The activation includes: fumigating the freshly prepared catechu[9] aromatics with n-pentane and / or n-hexane vapors, and heating at 60~90°C after fumigation to obtain the porous catechu[9] aromatics material; The self-healing process includes fumigating the structurally collapsed non-porous catechin[9] aromatic material with n-pentane and / or n-hexane vapors to obtain the porous catechin[9] aromatic material.

3. The application according to claim 2, characterized in that, The fumigation time is 12-24 hours; The heating time is 12-24 hours.

4. A method for adsorption separation of methane and C2 / C3 alkanes, characterized in that, Using porous catechu[9] aromatic material as an adsorbent, a mixture containing methane and C2 / C3 alkanes is contacted with the adsorbent, and the adsorbent selectively adsorbs C2 / C3 alkanes to achieve methane purification; The porous catechin[9] aromatic material has the following chemical structure: ； The C2 / C3 alkanes are ethane and propane.

5. The method according to claim 4, characterized in that, The porous catechu[9] aromatic material is activated or self-healed before contacting the mixture; The activation includes: fumigating the freshly prepared catechu[9] aromatics with n-pentane and / or n-hexane vapors, and heating at 60~90°C after fumigation to obtain the porous catechu[9] aromatics material; The self-healing process includes fumigating the structurally collapsed non-porous catechin[9] aromatic material with n-pentane and / or n-hexane vapors to obtain the porous catechin[9] aromatic material.

6. The method according to claim 5, characterized in that, The fumigation time is 12-24 hours; The heating time is 12-24 hours.

7. The method according to any one of claims 4 to 6, characterized in that, The mixture contains 50-99% methane in molar proportion; The mixture also contains water.

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