Molecular sieve ssz-13 having a cha framework, methods of making and use thereof

Abstract

The application discloses a molecular sieve SSZ-13 with a CHA framework and a preparation method and application thereof, and belongs to the technical field of molecular sieves. The preparation method of the molecular sieve SSZ-13 comprises the following steps: S1, mixing raw materials including a silicon source, an aluminum source, an organic template agent, a FAU zeolite precursor solution and deionized water to obtain an initial reaction gel; S2, heating and crystallizing the initial reaction gel in step S1 under a closed condition to obtain a crystallization product; and S3, centrifuging, washing and drying the crystallization product in step S2 to obtain the SSZ-13 zeolite molecular sieve. The method is simple and easy to operate, has low cost, and has high product purity and regular morphology; and the molecular sieve has excellent selective adsorption and separation effect on low-carbon olefins and alkanes.

Description

Technical Field

[0001] This application belongs to the field of molecular sieve technology, and particularly relates to a molecular sieve SSZ-13 with a CHA framework, its preparation method and application. Background Technology

[0002] SSZ-13 is an aluminosilicate zeolite molecular sieve with a CHA topology. It was first hydrothermally synthesized by Zone of Chevron Industries, Inc. Its framework structure consists of AlO4 and SiO4 tetrahedral structures linked end-to-end by oxygen atoms, arranged in a regular ellipsoidal cage with an 8-membered ring structure. The three-dimensional intersecting channel structure, channel size It belongs to the 8-membered ring microporous zeolite molecular sieve. These structural characteristics make SSZ-13 molecular sieve an excellent shape-selective reactor for small molecules, exhibiting excellent catalytic performance in various reactions such as selective adsorption and separation of small molecule gases, selective catalytic reduction of nitrogen oxides (SCR), and methanol-to-olefins (MTO).

[0003] The synthesis of SSZ-13 zeolite molecular sieves typically requires the use of expensive N,N,N-trimethyladamantaneamine as an organic template agent, which significantly increases the synthesis cost. In recent years, researchers have been searching for simpler, more feasible, and lower-cost synthetic methods to synthesize SSZ-13.

[0004] The literature Progress in synthesis of SSZ-13 molecular sieves (Modern Chemical Industry., 2019; 39:53-57) reports a series of synthetic methods for SSZ-13 silicoaluminite molecular sieves with CHA framework structure. Although it discloses the synthesis of SSZ-13 using inexpensive and non-toxic choline chloride as a template agent, it still requires the addition of SSZ-13 seed crystals. Summary of the Invention

[0005] In view of this, this application provides a molecular sieve SSZ-13 with a CHA framework, its preparation method and application, with the main purpose of solving the technical problem of the complex synthesis method of molecular sieve SSZ-13.

[0006] On the one hand, this application provides a method for preparing SSZ-13 molecular sieve with a CHA framework, the method comprising the following steps:

[0007] S1: Mix raw materials containing silicon source I, aluminum source I, organic template agent, FAU zeolite precursor solution and deionized water I to obtain the initial gel;

[0008] The organic template agent is selected from 1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidine bromide;

[0009] The FAU zeolite precursor solution is obtained by mixing and aging raw materials containing aluminum source II, silicon source II, inorganic alkali and water II;

[0010] S2: The initial gel from step S1 is heated and crystallized under sealed conditions to obtain a crystallized product;

[0011] S3: The crystallized product from step S2 is centrifuged, washed, and dried to obtain the SSZ-13 zeolite molecular sieve.

[0012] In this application, the FAU zeolite precursor solution provides all the inorganic base sources and part of the silicon, aluminum and water sources required for the reaction system.

[0013] Optionally, in step S1, the molar ratio of silicon source (silicon source I + silicon source II), aluminum source (aluminum source I + aluminum source II), inorganic base, organic template agent, and water (water I + water II) in the initial gel is:

[0014] SiO2 / Al2O3 = 20-40;

[0015] NaOH / SiO2 = 0.3–1.0;

[0016] H2O / SiO2 = 5~30;

[0017] R / SiO2 = 0.05–0.3;

[0018] Among them, the number of moles of silicon source is calculated as the number of moles of SiO2, the number of moles of aluminum source is calculated as the number of moles of Al2O3, the number of moles of inorganic base is calculated as the number of moles of sodium ions in the FAU zeolite precursor solution, the number of moles of organic template agent is calculated as the number of moles of R, and the number of moles of water is calculated as the number of moles of H2O itself.

[0019] The silicon source in the initial gel of this application comes partly from the silicon source in the FAU precursor solution and partly from an external silicon source; the aluminum source and water also come partly from an external source and partly from the FAU precursor solution.

[0020] Optionally, the organic template agent R is selected from 1-methyl-1-propylpiperidine bromide or 1-methyl-1-butylpyrrolidine bromide.

[0021] Optionally, in step S1, the molar ratio of SiO2 / Al2O3 in the initial gel is selected from any value of 20, 22, 25, 28, 30, 32, 35, 38, 40 or any range between the two.

[0022] The molar ratio of NaOH / SiO2 is selected from any value of 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or any value in between.

[0023] The molar ratio of H2O / SiO2 is selected from any value of 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30 or any range between the two.

[0024] The molar ratio of R / SiO2 is selected from any value of 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3 or any value in between.

[0025] Optionally, in step S1, the molar ratio of silicon source, aluminum source, inorganic alkali, and water in the FAU zeolite precursor solution is:

[0026] SiO2 / Al2O3 = 10~40;

[0027] NaOH / SiO2 = 1.2–2.0;

[0028] H2O / SiO2 = 10~20;

[0029] The number of moles of water is calculated as the number of moles of H2O itself, the number of moles of silicon source is calculated as the number of moles of SiO2, the number of moles of aluminum source is calculated as the number of moles of Al2O3, and the number of moles of inorganic base is calculated as the number of moles of sodium ions.

[0030] Optionally, in step S1, the molar ratio of SiO2 / Al2O3 in the FAU zeolite precursor solution is selected from any value of 10, 12, 14, 15, 20, 22, 25, 28, 30, 32, 35, 38, 40 or any range between the two.

[0031] The molar ratio of NaOH / SiO2 is selected from any value of 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or any value in between.

[0032] The molar ratio of H2O / SiO2 is selected from any value of 10, 12, 15, 18, 20 or any range between the two.

[0033] Optionally, the preparation process of the FAU zeolite precursor solution in step S1 includes: mixing raw materials containing aluminum source, inorganic alkali and water, stirring until the aluminum source is completely dissolved, adding silicon source, continuing to stir until a clear and transparent solution is obtained, and aging at a temperature of 20 to 80°C for 6 to 24 hours to obtain the FAU zeolite precursor solution.

[0034] Optionally, the aging temperature is selected from 20, 30, 40, 50, 60, 70, or 80°C; the aging time is selected from any value of 6h, 10h, 15h, 20h, or 24h, or a range between any two.

[0035] Optionally, the silicon source in the initial gel is selected from at least one of silica, silica sol, silica gel chromatography, water glass, and tetraethyl orthosilicate.

[0036] Optionally, the silicon source in the FAU zeolite precursor solution is selected from at least one of silica, silica sol, silica gel chromatography, water glass, and tetraethyl orthosilicate.

[0037] Optionally, the aluminum source in the initial gel is selected from at least one of aluminum salts, aluminates, activated alumina, aluminum hydroxide, boehmite, aluminum isopropoxide, and aluminum n-butoxide.

[0038] Optionally, the aluminum source in the FAU zeolite precursor solution is selected from at least one of aluminum salts, aluminates, activated alumina, aluminum hydroxide, boehmite, aluminum isopropoxide, and aluminum n-butoxide.

[0039] Optionally, in step S2, the conditions for the heating crystallization include:

[0040] Crystallization temperature: 130~180℃;

[0041] Crystallization pressure: self-generated pressure;

[0042] Crystallization time: 12-120h.

[0043] Optionally, the crystallization temperature is selected from any value of 130, 140, 150, 160, 170, 180 or a range between any two.

[0044] The crystallization time is selected from any value of 12h, 20h, 30h, 40h, 50h, 60h, 70h, 80h, 90h, 100h, 110h, 120h or any range between the two.

[0045] Optionally, the crystallization is either dynamic crystallization or static crystallization.

[0046] Secondly, this application provides a molecular sieve SSZ-13 with a CHA framework, which is prepared by the above method.

[0047] Optionally, the molecular sieve SSZ-13 has a Si / Al ratio of 4.0 to 6.0 and a crystal size of 1 to 5 μm.

[0048] Optionally, the Si / Al ratio in the molecular sieve SSZ-13 is selected from any value of 4.0, 4.5, 5.0, 5.5, 6.0 or any range between two.

[0049] Optionally, the crystal size is 1–3 μm.

[0050] Thirdly, this application provides the application of the molecular sieve SSZ-13 with a CHA framework prepared by the above method in the adsorption and separation of carbon dioxide / low-carbon alkynes / low-carbon olefins / low-carbon alkanes.

[0051] Optionally, the SSZ-13 zeolite molecular sieve can be used as a selective adsorbent for C2H6 and C3H8 in C2H6 / CH4 mixed gas or C3H8 / CH4 mixed gas, a selective adsorbent for CO2 in CO2 / CH4 mixed gas or CO2 / N2 mixed gas, and can also be used as an adsorbent to purify C2H4 in C2H2 / CO2 / C2H4.

[0052] Compared with the prior art, this application has the following beneficial effects:

[0053] (1) The synthesis method of this application is simple and easy to implement, and the resulting silica-alumina zeolite molecular sieve SSZ-13 with CHA framework structure has high crystallinity and regular morphology.

[0054] (2) The zeolite precursor solution in this application is simple to prepare and can be stored at room temperature for a long time. As the aging time of the precursor solution increases, the crystallization time required to obtain pure phase SSZ-13 molecular sieve is short, which greatly saves the synthesis cost of SSZ-13.

[0055] (3) The SSZ-13 molecular sieve prepared in this application has high selective adsorption performance for C2H6, C3H8 and CO2. This application is not only of great significance for the synthesis of SSZ-13 molecular sieve, which has important industrial application prospects, but also can provide new methods and ideas for the synthesis of other molecular sieves. Attached Figure Description

[0056] Figure 1 These are the X-ray diffraction patterns of the SSZ-13 products prepared in Examples 1-6 of this application;

[0057] Figure 2 These are SEM images of the SSZ-13 products prepared in Examples 1-6 of this application;

[0058] (SEM scales are 20μm, 20μm, 30μm, 10μm, 10μm, 20μm respectively)

[0059] Figure 3This is the isothermal adsorption curve of the SSZ-13 product prepared in Example 1 of this application for small molecule gas. Detailed Implementation

[0060] The present application is further illustrated below with reference to specific embodiments. The following descriptions are merely a few embodiments of the present application and are not intended to limit the present application in any way. Although the present application discloses preferred embodiments as follows, they are not intended to limit the present application. Any modifications or variations made by those skilled in the art without departing from the scope of the technical solution of the present application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

[0061] Unless otherwise specified, the raw materials used in the embodiments of this application are all purchased commercially and used directly without any special treatment.

[0062] This application provides a specific preparation method for a silica-alumina SSZ-13 zeolite molecular sieve with a CHA framework structure: a silicon source, an aluminum source, an inorganic alkali source, an organic template agent (1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidine bromide), a FAU zeolite precursor solution, and deionized water are mixed and stirred evenly to obtain an initial reaction gel. The FAU zeolite precursor solution is obtained by mixing and aging raw materials containing an aluminum source, a silicon source, an inorganic alkali, and water. The initial reaction gel is then subjected to hydrothermal crystallization to obtain the SSZ-13 zeolite molecular sieve. The hydrothermal crystallization temperature is 130–180℃, and the time is 12–120 h.

[0063] As a preferred embodiment of the above, the silicon source preferably includes a solid silicon source, sodium silicate, silica sol, or silica. The silica content in the silica sol is preferably 30-50 wt%, more preferably 40 wt%; the silica content in the solid silicon source and silica is preferably 100 wt%.

[0064] As a preferred embodiment of the above, the aluminum source preferably includes aluminum hydroxide, sodium aluminate, aluminum isopropoxide, or boehmite.

[0065] As a preferred embodiment of the above, the content of the organic template agent 1-methyl-1-propylpiperidine bromide or 1-methyl-1-butylpyrrolidine bromide is 99.9 wt%; all organic template agents are commercially available chemicals.

[0066] This invention does not have any special limitation on water; any water known in the art can be used, such as deionized water, distilled water, ultrapure water, or high-purity water.

[0067] As a preferred embodiment of the above, the amounts of sodium hydroxide, silicon source, and aluminum source in the initial reactive gel, converted to Na2O, SiO2, and Al2O3 respectively, are calculated, and the molar ratio of sodium hydroxide, silicon source, aluminum source, and water is:

[0068] SiO2 / Al2O3 = 20-40;

[0069] NaOH / SiO2 = 0.5–0.9;

[0070] H2O / SiO2 = 5~20;

[0071] R / SiO2 = 0.05–0.3;

[0072] R represents 1-methyl-1-propylpiperidine bromide or 1-methyl-1-butylpyrrolidine bromide.

[0073] The preferred formulation of the initial reaction gel of the present invention is as follows:

[0074] SiO2 / Al2O3 = 20-35;

[0075] NaOH / SiO2 = 0.5–0.8;

[0076] H2O / SiO2 = 10-20;

[0077] R / SiO2 = 0.05 to 0.2.

[0078] The molar ratio of the FAU zeolite precursor solution in this invention is:

[0079] Al2O3 / SiO2 = 0.03–0.1;

[0080] NaOH / SiO2 = 1.2–2.0;

[0081] H2O / SiO2 = 10-20.

[0082] In this invention, the molar ratio of the FAU zeolite precursor solution is more preferably:

[0083] Al2O3 / SiO2 = 0.05–0.1;

[0084] NaOH / SiO2 = 1.5–2.0;

[0085] H2O / SiO2 = 15-20.

[0086] As a preferred embodiment of the above, the mixing of sodium hydroxide, silicon source, aluminum source, FAU zeolite precursor solution and water preferably includes the following steps:

[0087] Sodium hydroxide, water and aluminum source were first mixed and stirred at room temperature to obtain the first mixed system;

[0088] FAU zeolite precursor solution and organic template agent R were added to the first mixing system and stirred evenly at room temperature to obtain the second mixing system.

[0089] The silicon source was added to the second mixing system and stirred until homogeneous to obtain the initial reaction gel.

[0090] As a preferred embodiment of the above, the first mixing and the second mixing are preferably carried out independently in a closed container at room temperature and under stirring conditions; the stirring speed is preferably 200 to 800 rpm, more preferably 400 to 600 rpm; this application does not have a special limitation on the stirring and mixing time, as long as it can ensure that the raw materials are mixed evenly.

[0091] After obtaining the initial reaction gel, this application subjected the initial reaction gel to hydrothermal crystallization to obtain SSZ-13 zeolite molecular sieve; the hydrothermal crystallization temperature was 130-180℃ and the time was 12-120h.

[0092] As a preferred embodiment of the above, hydrothermal crystallization is preferably static crystallization.

[0093] As a preferred embodiment of the above, the hydrothermal crystallization temperature is preferably 130-180°C, more preferably 150-170°C; and the hydrothermal crystallization time is preferably 24-120 hours, more preferably 36-120 hours.

[0094] This application does not impose any special restrictions on the equipment used for hydrothermal crystallization; any hydrothermal crystallization equipment well known to those skilled in the art can be used. In the embodiments of this application, hydrothermal crystallization is preferably carried out in a hydrothermal reactor.

[0095] Following hydrothermal crystallization, this application preferably further includes the following steps:

[0096] The product obtained by hydrothermal crystallization was subjected to solid-liquid separation to obtain a solid.

[0097] The solid was dried to obtain SSZ-13 zeolite molecular sieve.

[0098] This application does not specify a particular method for solid-liquid separation; any solid-liquid separation method well-known in the art can be used. In the embodiments of this application, solid-liquid separation is preferably performed by vacuum filtration or centrifugation.

[0099] As a preferred embodiment of the above, the number of water washes is preferably 3. Drying is preferably oven drying; the drying temperature is preferably 75-100°C, more preferably 85-100°C; the drying time is preferably 6-24 hours, more preferably 8-12 hours.

[0100] The preparation method provided in this application does not require other zeolite molecular sieve precursors as raw materials or additional SZZ-13 zeolite molecular sieve precursors as seed crystals, which greatly reduces the synthesis cost; and can obtain high-purity SZZ-13 zeolite molecular sieves with safe reaction conditions; it significantly simplifies the production process and reduces production costs.

[0101] This application provides SZZ-13 zeolite molecular sieve prepared by the above preparation method, wherein the Si / Al molar ratio in the SZZ-13 zeolite molecule is 4 to 6.

[0102] As a preferred embodiment of the above, the Si / Al molar ratio in the SZZ-13 zeolite molecule is preferably 4.5 to 6.

[0103] The SZZ-13 zeolite molecular sieve provided in this application has high silicon content, high crystallinity, and uniform particle size, with a particle size of 1 to 3 μm.

[0104] This application also provides that the above-mentioned SZZ-13 zeolite molecular sieve can be applied to the selective adsorption and separation of low-carbon alkanes and carbon dioxide gases.

[0105] As a preferred embodiment of the above, SZZ-13 zeolite molecular sieve is preferably used as a selective adsorbent for C2H6 and C3H8 in C2H6 / CH4 mixed gas or C3H8 / CH4 mixed gas, as well as for the selective adsorption of CO2 in CO2 / CH4 mixed gas or CO2 / N2 and the purification of C2H4 in CO2 / C2H2 / C2H4 mixed gas.

[0106] As a preferred embodiment of the above embodiments, before selectively adsorbing low-carbon alkynes / olefins / alkanes and carbon dioxide gases, the SZZ-13 zeolite molecular sieve is preferably subjected to a template removal treatment. The template removal treatment temperature is preferably 600°C; the vacuum activation treatment temperature is preferably 350°C; and the vacuum activation treatment time is preferably 6–10 hours. This application does not have a specific limitation on the vacuum degree of the vacuum activation treatment; a vacuum degree well-known in the art can be used.

[0107] Examples 1-5 below illustrate the specific preparation methods of SZZ-13 zeolite molecular sieves.

[0108] Example 1

[0109] Preparation of FAU zeolite precursor solution:

[0110] Under sealed, room temperature, and stirring conditions, 6.53 g of sodium hydroxide, 1.23 g of sodium aluminate, and 19.8 g of deionized water were mixed thoroughly in a reaction vessel. Then, 15 g of silica sol (40 wt% SiO2) was added to obtain the initial gel of the FAU zeolite precursor solution; the molar ratio of SiO2:Al2O3:NaOH:H2O was 10.0:0.7:18:160. After stirring for 24 h at room temperature, the mixture was allowed to stand and age for 24 h at room temperature before being used in subsequent SSZ-13 synthesis experiments.

[0111] Synthesis of SSZ-13 zeolite molecular sieve:

[0112] Under sealed, room temperature, and stirring conditions, 4 g of FAU zeolite precursor solution, 0.035 g of aluminum hydroxide, and 4.6 g of deionized water were added to a reaction vessel and mixed thoroughly. Subsequently, 0.7 g of organic template agent 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO2 40wt%) were added and mixed thoroughly to obtain the initial reaction gel. The molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O was 1.0:0.0365:0.7:0.13:20.

[0113] The gel was statically crystallized at 150℃ for 96 h. The resulting crystallized system was cooled to room temperature and then centrifuged and washed. The resulting solid product was dried in an oven at 100℃ for 6 h to obtain SSZ-13 zeolite molecular sieve (abbreviated as S-1).

[0114] The X-ray powder diffraction pattern of the SSZ-13 zeolite molecular sieve prepared in this embodiment is as follows: Figure 1 As shown in curve S-1, by comparing with the standard diffraction pattern published by the International Molecular Sieve Association, it can be known that S-1 is an SSZ-13 zeolite molecular sieve with a CHA structure; the Si / (Si+Al) molar ratio of S-1 was measured to be 4.7 by XRF.

[0115] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this embodiment is shown below. Figure 2 As shown in S-1, by Figure 2 It can be seen that the particle size of S-1 is approximately 3 μm.

[0116] Example 2

[0117] Preparation of FAU zeolite precursor solution:

[0118] Under sealed, room temperature, and stirring conditions, 5.93 g of sodium hydroxide, 1.23 g of sodium aluminate, and 19.8 g of deionized water were mixed thoroughly in a reaction vessel. Then, 15 g of silica sol (40 wt% SiO2) was added to obtain the initial gel of the FAU zeolite precursor solution; the molar ratio of SiO2:Al2O3:NaOH:H2O was 10.0:0.7:16.5:160. After stirring for 24 h at room temperature, the mixture was aged at 50 °C for 24 h before being used in subsequent SSZ-13 synthesis experiments.

[0119] Synthesis of SSZ-13 zeolite molecular sieve:

[0120] Under sealed, room temperature, and stirring conditions, 4 g of FAU zeolite precursor solution, 0.035 g of aluminum hydroxide, and 4.6 g of deionized water were added to a reaction vessel and mixed thoroughly. Subsequently, 0.7 g of organic molar 1-methyl-1-butylpyrrolidine bromide (99.0 wt%) and 2.25 g of silica sol (SiO2 40 wt%) were added and mixed thoroughly to obtain the initial reaction gel. The molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O was 1.0:0.0365:0.7:0.13:20.

[0121] The gel was statically crystallized at 170℃ for 24h. The resulting crystallized system was cooled to room temperature and then centrifuged and washed. The resulting solid product was dried in an oven at 100℃ for 6h to obtain SSZ-13 zeolite molecular sieve (abbreviated as S-2).

[0122] The X-ray powder diffraction pattern of the SSZ-13 zeolite molecular sieve prepared in this embodiment is as follows: Figure 1 As shown in curve S-2, by comparing it with the standard diffraction pattern published by the International Molecular Sieve Association, it can be determined that S-2 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-1 was measured to be 4.7 by XRF.

[0123] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this embodiment is shown below. Figure 2 As shown in S-2, by Figure 2 It can be seen that the particle size of S-2 is approximately 3 μm.

[0124] Example 3

[0125] Preparation of FAU zeolite precursor solution:

[0126] Under sealed, room temperature, and stirring conditions, 5.93 g of sodium hydroxide, 1.23 g of sodium aluminate, and 19.8 g of deionized water were mixed thoroughly in a reaction vessel. Then, 6 g of silica was added to obtain the initial gel of the FAU zeolite precursor solution; the molar ratio of SiO2:Al2O3:NaOH:H2O was 10.0:0.7:16.5:160. After stirring for 24 h at room temperature, the mixture was aged at 50 °C for 24 h before being used in subsequent SSZ-13 synthesis experiments.

[0127] Synthesis of SSZ-13 zeolite molecular sieve:

[0128] Under sealed, room temperature, and stirring conditions, 4 g of FAU zeolite precursor solution, 0.035 g of aluminum hydroxide, and 4.6 g of deionized water were added to a reaction vessel and mixed thoroughly. Subsequently, 0.7 g of organic template agent 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO2 40wt%) were added and mixed thoroughly to obtain the initial reaction gel. The molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O was 1.0:0.0365:0.7:0.13:20.

[0129] The gel was statically crystallized at 180℃ for 12h. The resulting crystallized system was cooled to room temperature and then centrifuged and washed. The resulting solid product was dried in an oven at 100℃ for 12h to obtain SSZ-13 zeolite molecular sieve (abbreviated as S-3).

[0130] The X-ray powder diffraction pattern of the SSZ-13 zeolite molecular sieve prepared in this embodiment is as follows: Figure 1 As shown in curve S-2, by comparing with the standard diffraction pattern published by the International Molecular Sieve Association, it can be determined that S-3 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-3 was measured to be 5.0 by XRF.

[0131] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this embodiment is shown below. Figure 2 As shown in S-2, by Figure 3 It can be seen that the particle size of S-3 is approximately 3 μm.

[0132] Example 4

[0133] Preparation of FAU zeolite precursor solution:

[0134] Under sealed, room temperature, and stirring conditions, 5.33 g of sodium hydroxide, 1.23 g of sodium aluminate, and 19.8 g of deionized water were mixed thoroughly in a reaction vessel. Then, 6 g of silica was added to obtain the initial gel of the FAU zeolite precursor solution; the molar ratio of SiO2:Al2O3:NaOH:H2O was 10.0:0.7:15:160. After stirring for 24 h at room temperature, the mixture was aged at 60 °C for 24 h before being used in subsequent SSZ-13 synthesis experiments.

[0135] Synthesis of SSZ-13 zeolite molecular sieve:

[0136] Under sealed, room temperature, and stirring conditions, 4 g of FAU zeolite precursor solution and 4.6 g of deionized water were added to a reaction vessel and mixed thoroughly. Subsequently, 0.7 g of organic template agent 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO2 40wt%) were added and mixed thoroughly to obtain an initial reaction gel. The molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O was 1.0:0.028:0.7:0.13:20.

[0137] The gel was statically crystallized at 160℃ for 48h. After the crystallized system was cooled to room temperature, it was centrifuged and washed. The resulting solid product was dried in an oven at 100℃ for 12h to obtain SSZ-13 zeolite molecular sieve (abbreviated as S-4).

[0138] The X-ray powder diffraction pattern of the SSZ-13 zeolite molecular sieve prepared in this embodiment is as follows: Figure 1 As shown in curve S-4, by comparing with the standard diffraction pattern published by the International Molecular Sieve Association, it can be known that S-4 is an SSZ-13 zeolite molecular sieve with a CHA structure; the Si / (Si+Al) molar ratio of S-4 was measured to be 5.2 by XRF.

[0139] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this embodiment is shown below. Figure 2 As shown in S-4, by Figure 2 It can be seen that the particle size of S-4 is approximately 3 μm.

[0140] Example 5

[0141] Preparation of FAU zeolite precursor solution:

[0142] Under sealed, room temperature, and stirring conditions, 6.53 g of sodium hydroxide, 1.23 g of sodium aluminate, and 19.8 g of deionized water were mixed thoroughly in a reaction vessel. Then, 6 g of silica was added to obtain the initial gel of the FAU zeolite precursor solution; the molar ratio of SiO2:Al2O3:NaOH:H2O was 10.0:0.7:18:160. After stirring for 24 h at room temperature, the mixture was aged at 50 °C for 24 h before being used in subsequent SSZ-13 synthesis experiments.

[0143] Synthesis of SSZ-13 zeolite molecular sieve:

[0144] Under sealed, room temperature, and stirring conditions, 4 g of FAU zeolite precursor solution, 0.035 g of aluminum hydroxide, and 4.6 g of deionized water were added to a reaction vessel and mixed thoroughly. Subsequently, 0.54 g of organic template agent 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO2 40wt%) were added and mixed thoroughly to obtain an initial reaction gel. The molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O was 1.0:0.0365:0.7:0.1:10.

[0145] The gel was statically crystallized at 170℃ for 24h. After the crystallized system was cooled to room temperature, it was centrifuged and washed. The resulting solid product was dried in an oven at 100℃ for 12h to obtain SSZ-13 zeolite molecular sieve (abbreviated as S-5).

[0146] The X-ray powder diffraction pattern of the SSZ-13 zeolite molecular sieve prepared in this embodiment is as follows: Figure 1 As shown in curve S-5, by comparing it with the standard diffraction pattern published by the International Molecular Sieve Association, it can be determined that S-5 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-5 was measured to be 4.8 by XRF.

[0147] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this embodiment is shown below. Figure 2 As shown in S-5, by Figure 2 It can be seen that the particle size of S-5 is approximately 3 μm.

[0148] Example 6

[0149] Preparation of FAU zeolite precursor solution:

[0150] Under sealed, room temperature, and stirring conditions, 6.53 g of sodium hydroxide, 1.13 g of aluminum hydroxide, and 19.8 g of deionized water were mixed thoroughly in a reaction vessel. Then, 6 g of silica was added to obtain the initial gel of the FAU zeolite precursor solution; the molar ratio of SiO2:Al2O3:NaOH:H2O was 10.0:0.7:16.5:160. After stirring for 24 h at room temperature, the mixture was aged at 50 °C for 24 h before being used in subsequent SSZ-13 synthesis experiments.

[0151] Synthesis of SSZ-13 zeolite molecular sieve:

[0152] Under sealed, room temperature, and stirring conditions, 4 g of FAU zeolite precursor solution, 0.03 g of pseudoboehmite, and 4.6 g of deionized water were added to a reaction vessel and mixed thoroughly. Subsequently, 0.7 g of organic template agent 1-methyl-1-butylpyrrolidine bromide (99.0 wt%) and 0.44 g of silica were added and mixed thoroughly to obtain the initial reaction gel. The molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O was 1.0:0.0365:0.7:0.13:20.

[0153] The gel was statically crystallized at 130℃ for 120h. After the crystallized system was cooled to room temperature, it was centrifuged and washed. The resulting solid product was dried in an oven at 100℃ for 12h to obtain SSZ-13 zeolite molecular sieve (abbreviated as S-6).

[0154] The X-ray powder diffraction pattern of the SSZ-13 zeolite molecular sieve prepared in this embodiment is as follows: Figure 1 As shown in curve S-6, by comparing it with the standard diffraction pattern published by the International Molecular Sieve Association, it can be determined that S-6 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-5 was measured to be 4.6 by XRF.

[0155] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this embodiment is shown below. Figure 2 As shown in S-6, by Figure 2 It can be seen that the particle size of S-6 is approximately 3 μm.

[0156] The preparation method of SSZ-13 zeolite molecular sieve provided in this application is simple and the obtained sample has high purity; compared with the traditional synthesis method using trimethyladamantaneamine as an organic template agent, it effectively reduces the synthesis cost.

[0157] Application examples

[0158] The SSZ-13 zeolite molecular sieve prepared in Example 1 was subjected to a single-component gas isothermal adsorption-desorption test. Before the test, the SSZ-13 zeolite molecular sieve prepared in Example 1 was activated under vacuum conditions at 200–350 °C for 4–10 h. After the sample cooled to room temperature, the single-component gas isothermal adsorption-desorption test was performed at a test temperature of 298 K and a test pressure of 0–1 bar. The results are as follows. Figure 3 As shown.

[0159] Depend on Figure 3 It is known that the Na-SSZ-13 zeolite molecular sieve prepared in this invention has excellent selective adsorption and separation performance for mixed gases such as C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, and CO2 / N2.

[0160] The SSZ-13 molecular sieve prepared in this application can be used for the selective adsorption and separation of low-carbon olefins and alkanes with excellent separation effect.

[0161] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing SSZ-13 molecular sieve with a CHA framework, characterized in that, The method includes the following steps: S1: Mix raw materials containing silicon source, aluminum source, organic template agent, FAU zeolite precursor solution and deionized water to obtain initial gel; The organic template agent is selected from 1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidine bromide; The FAU zeolite precursor solution is obtained by mixing raw materials containing aluminum source, inorganic alkali and water, stirring until the aluminum source is completely dissolved, adding silicon source, continuing to stir until a clear and transparent solution is obtained, and aging at 20~80℃ for 6~24h. Furthermore, the molar ratio of silicon source, aluminum source, inorganic alkali, and water in the FAU zeolite precursor solution is: SiO2 / Al2O3 = 10 ~ 40; NaOH / SiO2 = 1.2 ~ 2.0; H2O / SiO2 = 10 ~ 20; The number of moles of water is calculated based on the number of moles of H2O itself, the number of moles of silicon source is calculated based on the number of moles of SiO2, the number of moles of aluminum source is calculated based on the number of moles of Al2O3, and the number of moles of inorganic base is calculated based on the number of moles of sodium ions. S2: The initial gel from step S1 is heated and crystallized under sealed conditions to obtain a crystallized product; S3: After centrifuging, washing and drying the crystallized product in step S2, the SSZ-13 zeolite molecular sieve is obtained.

2. The method for preparing the molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, In step S1, the molar ratio of silicon source, aluminum source, inorganic base, organic template agent, and water in the initial gel is: SiO2 / Al2O3 = 20 ~ 40; NaOH / SiO2 = 0.3 ~ 1.0; H2O / SiO2 = 5 ~ 30; R / SiO2 = 0.05 ~ 0.3; Among them, the number of moles of silicon source is calculated as the number of moles of SiO2, the number of moles of aluminum source is calculated as the number of moles of Al2O3, the number of moles of inorganic base is calculated as the number of moles of sodium ions in the FAU zeolite precursor solution, the number of moles of organic template agent is calculated as the number of moles of R, and the number of moles of water is calculated as the number of moles of H2O itself.

3. The method for preparing the molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, The silicon source in the initial gel or the FAU zeolite precursor solution is independently selected from at least one of silica, silica sol, silica gel chromatography, water glass, and tetraethyl orthosilicate.

4. The method for preparing the molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, The aluminum source in the initial gel or the FAU zeolite precursor solution is independently selected from at least one of aluminates, activated alumina, aluminum hydroxide, boehmite, aluminum isopropoxide, and aluminum n-butoxide.

5. The method for preparing the molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, In step S2, the conditions for the heating crystallization include: Crystallization temperature: 130 ~ 180 ℃; Crystallization pressure: self-generated pressure; Crystallization time: 12 ~ 120 h; The crystallization can be dynamic or static.

6. A molecular sieve SSZ-13 with a CHA framework, characterized in that, It is prepared by the method described in any one of claims 1 to 5.

7. The molecular sieve SSZ-13 with a CHA framework according to claim 6, characterized in that, The molecular sieve SSZ-13 has a Si / Al ratio of 4.0 to 6.0 and a crystal size of 1 to 5 μm.

8. The application of the molecular sieve SSZ-13 with a CHA framework prepared by the method according to any one of claims 1 to 5 in the adsorption and separation of carbon dioxide / low carbon alkynes / low carbon olefins / low carbon alkanes.

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