Molecular sieve SSZ-13 with CHA skeleton and preparation method and application thereof

Abstract

The invention 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 containing a silicon source, an aluminum source, an organic template agent, an FAU zeolite precursor solution and deionized water to obtain initial reaction gel; s2, heating and crystallizing the initial reaction gel in the step S1 under a closed condition to obtain a crystallized product; and S3, centrifuging, washing and drying the crystallized product in the step S2 to obtain the SSZ-13 zeolite molecular sieve. The method is simple and easy to operate and low in cost, and the obtained product is high in purity, regular in morphology and excellent in selective adsorption separation effect on low-carbon olefin and alkane.

Description

Technical Field

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

[0002] SSZ-13 is a silicoaluminate zeolite molecular sieve with a CHA topological structure. It was first hydrothermally synthesized by Zone of Chevron Corporation in the United States. Its framework structure is composed of AlO4 and SiO4 tetrahedral structures connected end to end by oxygen atoms, and regularly arranged into an ellipsoidal cage with an 8-membered ring structure and a three-dimensional cross-linked pore structure, and the pore size belongs to the 8-membered ring small pore zeolite molecular sieve. These structural characteristics make the SSZ-13 molecular sieve an excellent small molecule shape-selective reactor, and it exhibits excellent catalytic performance in various reactions such as selective adsorption and separation of small molecule gases, selective catalytic reduction (SCR) of nitrogen oxides, and methanol to olefins (MTO).

[0003] The synthesis of SSZ-13 zeolite molecular sieve usually requires the use of expensive N, N, N-trimethyladamantylamine as an organic template agent, which greatly increases the synthesis cost. In recent years, people have been looking for simpler, easier and cheaper synthesis methods to synthesize SSZ-13.

[0004] The literature Progress in synthesis of SSZ-13 molecular sieves (Modern Chemical Industry., 2019; 39: 53-57) reported a series of synthesis methods of the silicoaluminum zeolite molecular sieve SSZ-13 with a CHA framework structure. Although it disclosed the synthesis of SSZ-13 using cheap and non-toxic choline chloride as a template agent, it still needed to additionally add SSZ-13 crystal seeds. 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, and the main purpose is to solve the technical problem of the complex synthesis method of the molecular sieve SSZ-13.

[0006] On the one hand, this application provides a preparation method of a molecular sieve SSZ-13 with a CHA framework, and the method includes the following steps:

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

[0008] Among them, the organic template is selected from 1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidinium bromide;

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

[0010] S2: Heating and crystallizing the initial gel in step S1 under closed conditions to obtain a crystallized product;

[0011] S3: Centrifuging, washing, and drying the crystallized product in step S2 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 source, aluminum source, and water required for the reaction system.

[0013] Optionally, in step S1, the molar ratio of the silicon source (silicon source I + silicon source II), aluminum source (aluminum source I + aluminum source II), inorganic base, organic template, 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 molar amount of the silicon source is calculated as the molar amount of SiO2, the molar amount of the aluminum source is calculated as the molar amount of Al2O3, the molar amount of the inorganic base is calculated as the molar amount of sodium ions in the FAU zeolite precursor solution, the molar amount of the organic template is calculated as the molar amount of R, and the molar amount of water is calculated as the molar amount of H2O itself.

[0019] In the initial gel of this application, part of the silicon source comes from the silicon source in the FAU precursor solution, and part comes from the externally added silicon source; the aluminum source and water also come from the external addition and the FAU precursor solution respectively.

[0020] Optionally, the organic template R is selected from 1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidinium 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 the range value between any two of them;

[0022] The molar ratio of NaOH / SiO2 is selected from any value among 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or the range value between any two of them;

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

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

[0025] Optionally, in step S1, the molar ratio of the silicon source, aluminum source, inorganic base 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] Wherein, the molar number of water is based on the molar number of H2O itself, the molar number of the silicon source is based on the molar number of SiO2, the molar number of the aluminum source is based on the molar number of Al2O3, and the molar number of the inorganic base is based on the molar number 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 among 10, 12, 14, 15, 20, 22, 25, 28, 30, 32, 35, 38, 40 or the range value between any two of them;

[0031] The molar ratio of NaOH / SiO2 is selected from any value among 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or the range value between any two of them;

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

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

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

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

[0036] Optionally, the silicon source in the FAU zeolite precursor solution is selected from at least one of fumed silica, silica sol, chromatography silica gel, 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, pseudoboehmite, 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, pseudoboehmite, aluminum isopropoxide and aluminum n-butoxide.

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

[0040] Crystallization temperature: 130 - 180 °C;

[0041] Crystallization pressure: autogenous pressure;

[0042] Crystallization time: 12 - 120 h.

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

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

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

[0046] In a second aspect, the present application provides a molecular sieve SSZ-13 having a CHA framework, which is prepared by the above method.

[0047] Optionally, in the molecular sieve SSZ-13, Si / Al = 4.0 - 6.0 and the crystal size is 1 - 5 μm.

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

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

[0050] In a third aspect, the present application provides the use of the molecular sieve SSZ-13 having a CHA framework prepared by the above method in the adsorption separation of carbon dioxide / low-carbon alkynes / low-carbon olefins / low-carbon alkanes.

[0051] Optionally, the SSZ-13 zeolite molecular sieve is used as a selective adsorbent for C2H6 and C3H8 in a C2H6 / CH4 mixed gas or a C3H8 / CH4 mixed gas, a selective adsorbent for CO2 in a CO2 / CH4 mixed gas or a 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, the present application has the following beneficial effects:

[0053] (1) The synthesis method of the present application is simple and easy to implement, and the prepared silicon-aluminum zeolite molecular sieve SSZ-13 having a CHA framework structure has high crystallinity and regular morphology.

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

[0055] (3) The SSZ-13 molecular sieve prepared by the present application has high selective adsorption performance for C2H6, C3H8 and CO2. The present application not only has important significance for the synthesis and application of the SSZ-13 molecular sieve with important industrial application prospects, but also can provide new methods and ideas for the synthesis of other molecular sieves. Description of the Drawings

[0056] Figure 1 is the X-ray diffraction spectrum of the SSZ-13 products prepared in Examples 1-6 of the present application;

[0057] Figure 2 is the SEM scanning electron micrograph of the SSZ-13 products prepared in Examples 1-6 of the present application;

[0058] (The SEM scales are 20 μm, 20 μm, 30 μm, 10 μm, 10 μm, 20 μm in sequence)

[0059] Figure 3It is the isothermal adsorption curve of the SSZ-13 product prepared in Example 1 of the present application for small molecule gases. Detailed implementation manners

[0060] The present application will be further described below in conjunction with specific embodiments. The following descriptions are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed in preferred embodiments as follows, it is not intended to limit the present application. Any person skilled in the relevant art can make some changes or modifications within the scope of the technical solution of the present application by using the disclosed technical content, which are equivalent to equivalent embodiments and all fall within the scope of the technical solution.

[0061] Unless otherwise specified, the raw materials in the embodiments of the present application are purchased through commercial channels and used directly without any special treatment.

[0062] The present application provides a specific preparation method of a silicon-aluminum SSZ-13 zeolite molecular sieve with a CHA framework structure: mixing a silicon source, an aluminum source, an inorganic base source, an organic template agent (1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidinium bromide), an FAU zeolite precursor solution, and deionized water, and stirring evenly to obtain an initial reaction gel. Among them, the FAU zeolite precursor solution is obtained by mixing and aging raw materials containing an aluminum source, a silicon source, an inorganic base, and water; performing hydrothermal crystallization on the initial reaction gel to obtain an SSZ-13 zeolite molecular sieve; the temperature of the hydrothermal crystallization is 130-180 °C, and the time is 12-120 h.

[0063] As a preference of the above embodiment, the silicon source preferably includes a solid silicon source, sodium silicate, silica sol, or precipitated 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 precipitated silica is preferably 100 wt%.

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

[0065] As a preference of the above embodiment, the content of the organic template agent 1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidinium bromide is 99.9 wt%; the organic template agents are all commercially available chemical products.

[0066] The present invention has no special limitation on water, and the well-known water in the art can be used, such as deionized water, distilled water, ultrapure water, or high-purity water.

[0067] As a preference of the above embodiment, the amounts of sodium hydroxide, silicon source, and aluminum source in the initial reaction gel are calculated based on the amounts of Na2O, SiO2, and Al2O3 after conversion, 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-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidine.

[0073] The initial reaction gel formulation of the present invention is more preferably:

[0074] SiO2 / Al2O3 = 20 - 35;

[0075] NaOH / SiO2 = 0.5 - 0.8;

[0076] H2O / SiO2 = 10 - 20;

[0077] R / SiO2 = 0.05 - 0.2.

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

[0079] Al2O3 / SiO2 = 0.03 - 0.1;

[0080] NaOH / SiO2 = 1.2 - 2.0;

[0081] H2O / SiO2 = 10 - 20.

[0082] The molar ratio of the FAU zeolite precursor solution in the present invention 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 preference for the above embodiments, the mixing method of sodium hydroxide, silicon source, aluminum source, FAU zeolite precursor solution and water preferably includes the following steps:

[0087] Perform the first mixing of sodium hydroxide, water and aluminum source, and stir at room temperature until the first mixed system is obtained;

[0088] Add the FAU zeolite precursor solution and the organic template R into the first mixed system, and stir evenly at room temperature to obtain the second mixed system;

[0089] Add a silicon source to the second mixing system and stir evenly to obtain an initial reaction gel.

[0090] As a preference of the above embodiments, the first mixing and the second mixing are independently preferably carried out in a sealed container under room temperature conditions and under stirring conditions; the stirring speed is preferably 200 - 800 rpm, more preferably 400 - 600 rpm; there is no special limitation on the mixing time in this application, as long as it can ensure that each raw material is mixed evenly.

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

[0092] As a preference of the above embodiments, the hydrothermal crystallization method is preferably static crystallization.

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

[0094] This application has no special limitation on the equipment for hydrothermal crystallization, and the hydrothermal crystallization equipment well-known to those skilled in the art can be used. In the embodiments of this application, the hydrothermal crystallization is preferably carried out in a hydrothermal reaction kettle.

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

[0096] Perform solid-liquid separation on the product obtained by hydrothermal crystallization to obtain a solid;

[0097] Dry the solid to obtain SSZ-13 zeolite molecular sieve.

[0098] This application has no special limitation on the solid-liquid separation method, and the solid-liquid separation methods well-known in the art can be used. In the embodiments of this application, the solid-liquid separation is preferably filtration or centrifugal separation.

[0099] As a preference of the above embodiments, the number of water washing times is preferably 3 times. Drying is preferably drying by baking; the drying temperature is preferably 75 - 100 °C, more preferably 85 - 100 °C; the drying time is preferably 6 - 24 h, more preferably 8 - 12 h.

[0100] The preparation method provided by this application does not require using other zeolite molecular sieve precursors as raw materials or additionally adding SZZ-13 zeolite molecular sieve precursors as seeds, which greatly reduces the synthesis cost; and high-purity SZZ-13 zeolite molecular sieve can be obtained, and the reaction conditions are safe; the production process is significantly simplified and the production cost is reduced.

[0101] The present application provides the SSZ-13 zeolite molecular sieve prepared by the above preparation method. In the SSZ-13 zeolite molecular sieve, the Si / Al molar ratio = 4 - 6.

[0102] As a preference of the above embodiment, the Si / Al molar ratio in the SSZ-13 zeolite molecular sieve is preferably 4.5 - 6.

[0103] The SSZ-13 zeolite molecular sieve provided by the present application has a high silicon content, a high crystallinity and a uniform particle size, and the particle size is 1 - 3 μm.

[0104] The present application also provides that the above SSZ-13 zeolite molecular sieve can be applied to the field of selective adsorption and separation of light alkanes and carbon dioxide gas.

[0105] As a preference of the above embodiment, the SSZ-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, for the selective adsorption of CO2 in CO2 / CH4 mixed gas or CO2 / N2, and for the purification of C2H4 in CO2 / C2H2 / C2H4 mixed gas.

[0106] As a preference of the above embodiment, before the SSZ-13 zeolite molecular sieve selectively adsorbs light alkynes / alkenes / alkanes and carbon dioxide gas, it is preferably to perform a dealuminizing agent treatment on the SSZ-13 zeolite molecular sieve first. The temperature of the dealuminizing agent treatment is preferably 600 °C; the temperature of the vacuum activation treatment is preferably 350 °C; the time of the vacuum activation treatment is preferably 6 - 10 h. The present application has no special limitation on the vacuum degree of the vacuum activation treatment, and the well-known vacuum degree in the art can be adopted.

[0107] The following Examples 1 - 5 are the specific preparation methods of the SSZ-13 zeolite molecular sieve.

[0108] Example 1

[0109] Preparation of the FAU zeolite precursor solution:

[0110] Under the conditions of airtight, room temperature and stirring, 6.53 g of sodium hydroxide, 1.23 g of sodium metaaluminate and 19.8 g of deionized water were added to a reaction vessel and mixed evenly, and then 15 g of silica sol (SiO2 40 wt%) was added to obtain the initial gel of the FAU zeolite precursor solution; wherein, the molar ratio of SiO2:Al2O3:NaOH:H2O = 10.0:0.7:18:160. Under the room temperature condition, after stirring for 24 h, it was left to age at room temperature for 24 h and then used for the subsequent SSZ-13 synthesis experiment.

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

[0112] Under airtight, 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 evenly. Subsequently, 0.7 g of organic template 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO₂ 40 wt%) were added and mixed evenly to obtain an initial reaction gel; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:OSDA:H₂O = 1.0:0.0365:0.7:0.13:20.

[0113] The gel was statically crystallized at 150 °C for 96 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried 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 example is as Figure 1 shown by curve S-1 in. By comparing with the standard diffraction pattern published by the International Zeolite 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 measured by XRF = 4.7.

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

[0116] Example 2

[0117] Preparation of FAU zeolite precursor solution:

[0118] Under airtight, 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 added to a reaction vessel and mixed evenly. Subsequently, 15 g of silica sol (SiO₂ 40 wt%) was added to obtain an initial gel of FAU zeolite precursor solution; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:H₂O = 10.0:0.7:16.5:160. Under room temperature conditions, after stirring for 24 h, it was left to age at 50 °C for 24 h and then used for subsequent SSZ-13 synthesis experiments.

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

[0120] Under airtight, 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 evenly. Subsequently, 0.7 g of organic template 1-methyl-1-butylpyrrolidinium bromide (99.0 wt%) and 2.25 g of silica sol (SiO2 40 wt%) were added and mixed evenly to obtain an initial reaction gel; wherein, the molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O = 1.0:0.0365:0.7:0.13:20.

[0121] The gel was statically crystallized at 170 °C for 24 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 6 h 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 example is as Figure 1 shown by the curve S-2 in. By comparing with the standard diffraction pattern published by the International Zeolite Association, it can be known that S-2 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-1 measured by XRF = 4.7.

[0123] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this example is as Figure 2 shown by S-2 in. From Figure 2 it can be seen that the particle size of S-2 is about 3 μm.

[0124] Example 3

[0125] Preparation of FAU zeolite precursor solution:

[0126] Under airtight, 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 added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain an initial gel of FAU zeolite precursor solution; wherein, the molar ratio of SiO2:Al2O3:NaOH:H2O = 10.0:0.7:16.5:160. Under room temperature conditions, after stirring for 24 h, it was left to age at 50 °C for 24 h and then used for subsequent SSZ-13 synthesis experiments.

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

[0128] Under airtight, room temperature and stirring conditions, 4 g of the 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 evenly. Subsequently, 0.7 g of the organic template 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO2 40 wt%) were added and mixed evenly to obtain an initial reaction gel; wherein, the molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O = 1.0:0.0365:0.7:0.13:20.

[0129] The gel was statically crystallized at 180 °C for 12 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h to obtain the 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 example is as Figure 1 shown by curve S-2 in. By comparing with the standard diffraction pattern published by the International Zeolite Association, it can be known that S-3 is the SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-3 measured by XRF = 5.0.

[0131] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this example is as Figure 2 shown by S-2 in. It can be seen from Figure 3 that the particle size of S-3 is about 3 μm.

[0132] Example 4

[0133] Preparation of the FAU zeolite precursor solution:

[0134] Under airtight, 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 added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain the initial gel of the FAU zeolite precursor solution; wherein, the molar ratio of SiO2:Al2O3:NaOH:H2O = 10.0:0.7:15:160. Under room temperature conditions, after stirring for 24 h, it was left to age at 60 °C for 24 h and then used for the subsequent SSZ-13 synthesis experiment.

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

[0136] Under airtight, 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 evenly. Subsequently, 0.7 g of organic template 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO₂ 40 wt%) were added and mixed evenly to obtain an initial reaction gel. Among them, the molar ratio of SiO₂:Al₂O₃:NaOH:OSDA:H₂O = 1.0:0.028:0.7:0.13:20.

[0137] The gel was statically crystallized at 160 °C for 48 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h 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 example is as Figure 1 shown by the curve S-4 in. By comparing with the standard diffraction pattern published by the International Zeolite 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 measured by XRF = 5.2.

[0139] The scanning electron microscope image of the SSZ-13 zeolite molecular sieve prepared in this example is as Figure 2 shown by S-4 in. From Figure 2 it can be seen that the particle size of S-4 is about 3 μm.

[0140] Example 5

[0141] Preparation of FAU zeolite precursor solution:

[0142] Under airtight, 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 added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain an initial gel of FAU zeolite precursor solution; among them, the molar ratio of SiO₂:Al₂O₃:NaOH:H₂O = 10.0:0.7:18:160. Under room temperature conditions, after stirring for 24 h, it was left to age at 50 °C for 24 h and then used for subsequent SSZ-13 synthesis experiments.

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

[0144] Under airtight, 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 evenly. Subsequently, 0.54 g of organic template 1-methyl-1-propylpiperidinium bromide and 2.25 g of silica sol (SiO2 40 wt%) were added and mixed evenly to obtain an initial reaction gel. Among them, the molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O = 1.0:0.0365:0.7:0.1:10.

[0145] The gel was statically crystallized at 170 °C for 24 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h 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 example is as Figure 1 shown by the curve S-5 in. By comparing with the standard diffraction pattern published by the International Zeolite Association, it can be known that S-5 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si+Al) molar ratio of S-5 measured by XRF = 4.8.

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

[0148] Example 6

[0149] Preparation of FAU zeolite precursor solution:

[0150] Under airtight, 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 added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain an initial gel of FAU zeolite precursor solution; among them, the molar ratio of SiO2:Al2O3:NaOH:H2O = 10.0:0.7:16.5:160. Under room temperature conditions, after stirring for 24 h, it was left to age at 50 °C for 24 h and then used for subsequent SSZ-13 synthesis experiments.

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

[0152] Under airtight, 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 evenly. Subsequently, 0.7 g of organic template 1-methyl-1-butylpyrrolidinium bromide (99.0 wt%) and 0.44 g of silica white were added and mixed evenly to obtain an initial reaction gel; wherein, the molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O = 1.0:0.0365:0.7:0.13:20.

[0153] The gel was statically crystallized at 130 °C for 120 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h 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 example is as Figure 1 shown by the curve S-6 in. By comparing with the standard diffraction pattern published by the International Zeolite Association, it can be known that S-6 is an SSZ-13 zeolite molecular sieve with a CHA structure. The Si / (Si + Al) molar ratio of S-5 measured by XRF = 4.6.

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

[0156] The preparation method of the 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 trimethyladamantylamine as the organic template, the synthesis cost is effectively reduced.

[0157] Application Example

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

[0159] It can be Figure 3 seen that the Na-SSZ-13 zeolite molecular sieve prepared in the present 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, CO2 / N2, etc.

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

[0161] As described above, only several embodiments of this application are presented, and there is no limitation to this application in any form. Although this application is disclosed with preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art, without departing from the scope of the technical solution of this application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A preparation method of molecular sieve SSZ-13 with a CHA framework, characterized in that, The method includes the following steps: S1: Mix raw materials including a silicon source, an aluminum source, an organic template agent, an FAU zeolite precursor solution, and deionized water to obtain an initial gel; Among them, the organic template agent is selected from 1-methyl-1-propylpiperidinium bromide or 1-methyl-1-butylpyrrolidine; The FAU zeolite precursor solution is obtained by mixing and aging raw materials including an aluminum source, a silicon source, an inorganic base, and water; S2: Heat and crystallize the initial gel in step S1 under closed conditions to obtain a crystallized product; S3: Centrifuge, wash, and dry the crystallized product in step S2 to obtain the SSZ-13 zeolite molecular sieve.

2. The preparation method of molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, In step S1, the molar ratio of the 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 molar number of the silicon source is counted as the molar number of SiO2, the molar number of the aluminum source is counted as the molar number of Al2O3, the molar number of the inorganic base is counted as the molar number of sodium ions in the FAU zeolite precursor solution, the molar number of the organic template agent is counted as the molar number of R, and the molar number of water is counted as the molar number of H2O itself.

3. The preparation method of molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, In step S1, the molar ratio of the silicon source, aluminum source, inorganic base, and water in the FAU zeolite precursor solution is: SiO2 / Al2O3 = 10 - 40; NaOH / SiO2 = 1.2 - 2.0; H2O / SiO2 = 10 - 20; Among them, the molar number of water is counted as the molar number of H2O itself, the molar number of the silicon source is counted as the molar number of SiO2, the molar number of the aluminum source is counted as the molar number of Al2O3, and the molar number of the inorganic base is counted as the molar number of sodium ions.

4. The preparation method of molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, The preparation process of the FAU zeolite precursor solution in step S1 includes: Mix raw materials including an aluminum source, an inorganic base, and water, stir until the aluminum source is completely dissolved, add the silicon source, and continue to stir until a clear and transparent solution is obtained. Age at a temperature of 20 - 80°C for 6 - 24 h to obtain the FAU zeolite precursor solution.

5. The preparation method of 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 fumed silica, silica sol, chromatography silica gel, water glass, and tetraethyl orthosilicate.

6. The preparation method of 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 aluminum salts, aluminates, activated alumina, aluminum hydroxide, pseudo-boehmite, aluminum isopropoxide, and aluminum n-butoxide.

7. The preparation method of molecular sieve SSZ-13 with a CHA framework according to claim 1, characterized in that, In step S2, the conditions for the heat crystallization include: Crystallization temperature: 130 - 180°C; Crystallization pressure: autogenous pressure; Crystallization time: 12 - 120 h; Preferably, the crystallization is dynamic crystallization or static crystallization.

8. A molecular sieve SSZ-13 with a CHA framework, characterized in that, It is prepared by the method according to any one of claims 1 - 7.

9. A zeolite SSZ-13 with a CHA framework according to claim 8, characterized in that, In the molecular sieve SSZ-13, Si / Al = 4.0 - 6.0, and the crystal size is 1 - 5 μm.

10. Use of the zeolite SSZ-13 with a CHA framework prepared by the method according to any one of claims 1 to 7 in the adsorption separation of carbon dioxide / lower alkynes / lower olefins / lower alkanes.

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