SAPO-34 molecular sieve with hollow structure as well as preparation method and application of SAPO-34 molecular sieve
The preparation of hollow structure SAPO-34 molecular sieve through hydrothermal synthesis and triethylamine templates solved the problem of rapid catalyst deactivation in the MTO process, achieved the extension of the catalyst life and performance improvement, and simplified the synthesis process and Reduced costs.
Patent Information
- Application Number
- CN202411343737.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-31
AI Technical Summary
During the methanol-to-olefin (MTO) process, SAPO-34 molecular sieve has severe coke deposition due to small pore size and long diffusion path, low catalyst utilization, and existing improved methods are complex and costly, and the use of secondary templates increases synthesis complexity. .
Triethylamine is used as the template agent to prepare SAPO-34 molecular sieve with hollow structure by hydrothermal synthesis method, simplifying the synthesis process, reducing the silicon content, controlling the aging time to adjust the hollow structure, and improving catalytic performance.
It significantly extends the service life of the catalyst, simplifies the synthesis process, improves the catalytic performance, reduces production costs, and avoids the formation of coke deposition.
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Figure CN119219024A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of molecular sieves, and in particular to a SAPO-34 molecular sieve with a hollow structure and a preparation method and application thereof. Background Art
[0002] The growth of light olefin demand and the constraints of crude oil have promoted the rapid development of methanol to olefin (MTO) process. Silicoaluminophosphate SAPO-34 molecular sieve with mild acidity has been proved to be one of the most promising catalysts in methanol to olefin (MTO) reaction due to its excellent selectivity for ethylene and propylene. This is because SAPO-34 catalyst has moderate acid strength and suitable pore size, which inhibits the conversion of light olefins to alkanes and the formation of large molecular olefins.
[0003] SAPO-34 is a microporous molecular sieve composed of SiO4, AlO4, and PO4 tetrahedrons connected alternately, and its topological structure is CHA type. The interior is an ellipsoidal cage composed of eight-membered rings and a three-dimensional pore structure. The pore diameter of SAPO-34 is small, about On the one hand, the small pores can screen the reaction molecules entering or flowing out of SAPO-34 zeolite according to the molecular size, which limits the diffusion of macrocyclic products and is conducive to the formation of low-carbon olefins such as ethylene and propylene. Therefore, it is widely used in the MTO reaction in industry. However, on the other hand, the small pore size and long diffusion path of SAPO-34 molecular sieve accommodate a large amount of organic matter with large volume, resulting in serious coke deposition and low utilization rate in microporous SAPO-34 molecular sieve, which leads to rapid deactivation of the catalyst in the MTO process. In order to avoid the above disadvantages, people have been committed to integrating mesopores or macropores into the microporous molecular sieve domain to form hollow SAPO-34 cubes with unique internal structures, overcome the diffusion limitation of SAPO-34, delay the formation of coke, and improve its catalytic performance. So far, several effective synthesis methods have been developed, such as microwave-assisted synthesis, sonochemical-assisted synthesis, surfactant-assisted synthesis, etching framework atom post-synthesis, seed-assisted synthesis, soft template and hard template methods, and finally obtain structurally hollow SAPO-34 crystals.
[0004] However, these methods usually involve tedious and complicated steps and procedures or use additional secondary templates, the use of which inevitably increases the complexity of the synthesis process and the production cost. In addition, some amorphous residues extracted from the zeolite body during post-treatment may partially block the zeolite channels. Therefore, a simple, economical, and environmentally feasible synthetic route for preparing hierarchical zeolites is worth exploring and developing. Summary of the invention
[0005] In order to solve the above technical problems, the present invention provides a SAPO-34 molecular sieve with a hollow structure and a preparation method and application thereof. The present invention uses triethylamine as a template and adopts a simple and environmentally friendly hydrothermal synthesis method to prepare a SAPO-34 molecular sieve with a hollow structure. Compared with conventional SAPO-34, the SAPO-34 molecular sieve with a hollow structure synthesized by this method can significantly change its MTO catalytic performance.
[0006] To this end, the present invention provides the following technical solutions:
[0007] In a first aspect, the present invention provides, in an optional embodiment, a method for preparing a SAPO-34 molecular sieve having a hollow structure, comprising the following steps:
[0008] S1: dissolving an aluminum source and a phosphorus source in water and stirring, then adding triethylamine and stirring, and finally adding a silicon source and stirring to obtain a gel;
[0009] S2: aging, crystallizing, centrifuging, washing and drying the gel to obtain a SAPO-34 molecular sieve having a hollow structure;
[0010] The molar ratio of aluminum atoms in the aluminum source, phosphorus atoms in the phosphorus source, silicon atoms in the silicon source and triethylamine is 2:1.2-1.8:0.18-0.28:2-3.
[0011] Preferably, the aging time is 16-22 hours. Preferably, the aging time is 18-20 hours. Furthermore, the aging time is 20 hours.
[0012] Preferably, the aluminum source is selected from one or more of aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite; and / or, the phosphorus source is selected from one or more of orthophosphoric acid or polyphosphoric acid. The silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or fumed silica.
[0013] Preferably, the crystallization temperature is 180-200° C.; and / or the crystallization time is 1-3 days.
[0014] In a second aspect, the present invention provides, in an optional embodiment, a SAPO-34 molecular sieve having a hollow structure, which is prepared by the above-mentioned preparation method.
[0015] In a third aspect, the present invention provides, in an optional embodiment, a SAPO-34 molecular sieve with a hollow structure prepared by the above preparation method or the use of the above SAPO-34 molecular sieve with a hollow structure as a catalyst in methanol to olefins.
[0016] Preferably, in the methanol to olefins process, the amount of the hollow structured SAPO-34 molecular sieve is 0.15-0.25 g; and / or the carrier gas flow rate is 15-25 mL / min; and / or the methanol injection flow rate is 0.005-0.015 mL / min; and / or the mass space velocity is 1 h -1 ; and / or, the vaporization chamber temperature is 120-180°C; and / or, the reaction temperature is 400-500°C.
[0017] The carrier gas is nitrogen.
[0018] Compared with the prior art, the present invention has one of the following beneficial effects:
[0019] 1. The present invention uses triethylamine as a template to prepare a SAPO-34 molecular sieve with a hollow structure. Compared with conventional SAPO-34, the SAPO-34 molecular sieve with a hollow structure synthesized by this method can significantly change its MTO catalytic performance and improve the service life of the catalyst.
[0020] 2. The present invention adopts a hydrothermal synthesis method, and can synthesize a SAPO-34 molecular sieve with a hollow structure by only reducing the silicon content in the SAPO-34 molecular sieve. Compared with the traditional hydrothermal synthesis method (i.e., without reducing the silicon content in the SAPO-34 molecular sieve), the preparation method of the present invention is simple and fast, and can directly obtain a SAPO-34 molecular sieve with a hollow structure.
[0021] 3. The present invention can adjust the hollow structure of SAPO-34 molecular sieve within a certain range by controlling the aging time during the preparation process, and can significantly change the catalytic performance of SAPO-34 molecular sieve in methanol to olefins. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0023] Figure 1 This is the powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Example 1 of the present invention;
[0024] Figure 2 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Example 1 of the present invention;
[0025] Figure 3 This is the powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Example 2 of the present invention;
[0026] Figure 4 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Example 2 of the present invention;
[0027] Figure 5 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 1 of the present invention;
[0028] Figure 6 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 1 of the present invention;
[0029] Figure 7 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 2 of the present invention;
[0030] Figure 8 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 2 of the present invention;
[0031] Fig. 9 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 3 of the present invention;
[0032] Fig.10 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 3 of the present invention;
[0033] Fig.11 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 4 of the present invention;
[0034] Fig.12 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 4 of the present invention;
[0035] Fig.13 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 5 of the present invention;
[0036] Fig.14 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 5 of the present invention;
[0037] Fig.15 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 6 of the present invention;
[0038] Fig.16 This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 6 of the present invention;
[0039] Fig.17 The powder X-ray diffraction pattern of the SAPO-34 molecular sieve prepared in Comparative Example 7 of the present invention;
[0040] Fig.18This is a scanning electron microscope image of the SAPO-34 molecular sieve prepared in Comparative Example 7 of the present invention. DETAILED DESCRIPTION
[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0042] In a specific embodiment of the present invention, the aluminum source is selected from one or more of aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite. The aluminum source can be a combination of any two of aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite. The mass ratio of any two combinations of aluminum sources in the present invention can be 1:0.5-2, but the present invention is not limited thereto.
[0043] In a specific embodiment of the present invention, the silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or fumed silica. The silicon source can be a combination of any two of silica sol, tetraethyl orthosilicate or fumed silica. The mass ratio of any two combinations of silicon sources in the present invention can be 1:0.5-2, but the present invention is not limited thereto.
[0044] The technical solution of the present invention will be described below in conjunction with embodiments.
[0045] Example 1
[0046] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.7:0.1:1.25, comprising the following steps:
[0047] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.89 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0048] S2: The gel aged for 20 hours was placed in a stainless steel reactor and crystallized at 200°C for 1 day. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder, which was the SAPO-34 molecular sieve with a hollow structure. The X-ray diffraction pattern of the SAPO-34 molecular sieve in this example is shown in Figure 1 , SEM images see Figure 2 .pass Figure 1 and Figure 2 It can be seen that after aging for 20 hours under low silicon conditions, a SAPO-34 molecular sieve containing an hourglass-shaped hollow structure was obtained.
[0049] Example 2
[0050] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.7:0.1:1.25, comprising the following steps:
[0051] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.89 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0052] S2: The gel after aging for 16 hours was placed in a stainless steel reactor and crystallized at 200°C for 1 day. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder, which was the SAPO-34 molecular sieve with a hollow structure. The X-ray diffraction pattern of the SAPO-34 molecular sieve in this example is shown in Figure 3 , SEM images see Figure 4 .pass Figure 3 and Figure 4 It can be seen that after aging for 16 hours under low silicon conditions, a SAPO-34 molecular sieve containing a cross-shaped hollow structure was obtained.
[0053] Comparative Example 1
[0054] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.7:0.1:1.25, comprising the following steps:
[0055] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.89 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0056] S2: The gel after aging for 12 hours was placed in a stainless steel reactor and crystallized at 200°C for 1 day. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder, which was the SAPO-34 molecular sieve with a hollow structure. The X-ray diffraction pattern of the SAPO-34 molecular sieve in this example is shown in Figure 5 , SEM images see Figure 6 .pass Figure 5 and Figure 6 It can be seen that after aging for 12 hours under low silicon conditions, a SAPO-34 molecular sieve with a plate-like hollow structure and containing other impurities was obtained.
[0057] Comparative Example 2
[0058] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.5:0.1:1.25, comprising the following steps:
[0059] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 11.02 ml of water, 1.38 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0060] S2: The gel aged for 20 hours was placed in a stainless steel reactor and crystallized at 200°C for 24 hours. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder, which was the SAPO-34 molecular sieve with a hollow structure. The X-ray diffraction pattern of the SAPO-34 molecular sieve in this example is shown in Figure 7 , SEM images see Figure 8 .pass Figure 7 and Figure 8 It can be seen that the purity of the SAPO-34 molecular sieve obtained after aging for 20 hours under this condition is lower than that of Example 1, and the hollow structure obtained is not uniform enough.
[0061] Comparative Example 3
[0062] This embodiment provides a method for preparing a SAPO-34 molecular sieve with a hollow structure. The raw materials are synthesized according to the molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:1:0.1:1.25, comprising the following steps:
[0063] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.68 ml of water, 2.76 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0064] S2: The gel after aging for 20 hours was placed in a stainless steel reactor and crystallized at 200°C for 24 hours. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder. Fig. 9 , SEM images see Fig.10 .pass Fig. 9 and Fig.10 It can be seen that after aging for 20 hours under this condition, a SAPO-34 molecular sieve with a plate-like hollow structure and containing relatively more other impurities was obtained.
[0065] Comparative Example 4
[0066] This comparative example provides a method for preparing a SAPO-34 molecular sieve with a hollow structure. The raw materials are synthesized according to the molar ratio of aluminum atoms in the aluminum source, phosphorus atoms in the phosphorus source, silicon atoms in the silicon source and triethylamine of 1:0.7:0.15:1.25, comprising the following steps:
[0067] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.76 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.52 ml of silica sol was added and stirred to obtain a gel.
[0068] S2: The gel after aging for 20 hours was placed in a stainless steel reactor and crystallized at 200°C for 24 hours. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder. Fig.11 , SEM images see Fig.12 .pass Fig.11 and Fig.12 It can be seen that the surface defect morphology of the SAPO-34 molecular sieve obtained after aging for 20 hours under this condition is no longer obvious.
[0069] Comparative Example 5
[0070] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.7:0.05:1.25, comprising the following steps:
[0071] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.95 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.26 ml of silica sol was added and stirred to obtain a gel.
[0072] S2: The gel after aging for 20 hours was placed in a stainless steel reactor and crystallized at 200°C for 24 hours. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder. Fig.13 , SEM images see Fig.14 .pass Fig.13 and Fig.14 It can be seen that after aging for 20 hours under this condition, a hollow structure with obvious surface defects but uneven surface was obtained, and SAPO-34 molecular sieve also contained certain impurities.
[0073] Comparative Example 6
[0074] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.7:0.1:1.25, comprising the following steps:
[0075] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.89 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0076] S2: The gel after aging for 6 hours was placed in a stainless steel reactor and crystallized at 200°C for 1 day. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder, which was the SAPO-34 molecular sieve with a hollow structure. The X-ray diffraction pattern of the SAPO-34 molecular sieve in this example can be found in Fig.15 , SEM images see Fig.16 .pass Fig.15 and Fig.16 It can be seen that after aging for 6 hours under low silicon conditions, a SAPO-34 molecular sieve with a plate-like hollow structure and containing other impurities was obtained.
[0077] Comparative Example 7
[0078] This embodiment provides a method for preparing a SAPO-34 molecular sieve having a hollow structure. The raw materials are synthesized according to a molar ratio of aluminum atoms in an aluminum source, phosphorus atoms in a phosphorus source, silicon atoms in a silicon source, and triethylamine of 1:0.7:0.1:1.25, comprising the following steps:
[0079] S1: At room temperature, 3.04 g of pseudo-boehmite was mixed with 10.89 ml of water, 1.93 ml of phosphoric acid was added, and the mixture was quickly stirred. Subsequently, 6.93 ml of triethylamine was added, and the mixture was stirred. Finally, 0.34 ml of silica sol was added and stirred to obtain a gel.
[0080] S2: The gel after aging for 24 hours was placed in a stainless steel reactor and crystallized at 200°C for 1 day. After the crystallization was completed, it was centrifuged, washed, and dried to obtain a white powder, which was the SAPO-34 molecular sieve with a hollow structure. The X-ray diffraction pattern of the SAPO-34 molecular sieve in this example is shown in Fig.17 , SEM images see Fig.18 .pass Fig.17 and Fig.18 It can be seen that the defect morphology of the SAPO-34 molecular sieve obtained after aging for 24 hours under this condition is no longer obvious.
[0081] Experimental example
[0082] The SAPO-34 molecular sieves prepared in Examples 1-2 and Comparative Examples 1-7 were subjected to MTO reaction. The specific method was as follows: the amount of SAPO-34 molecular sieve was 0.2 g, the carrier gas flow rate (nitrogen) was 20 ml / min, the injection flow rate of the raw material methanol was 0.01 ml / min, and the mass space velocity was 1 h -1 , the vaporization chamber temperature is 150°C, and the reaction temperature is 450°C. When conducting the MTO test, the SAPO-34 molecular sieve is sieved (40-60 mesh) and added to the quartz tube. Before the reaction, the SAPO-34 molecular sieve is pretreated at 400°C for 1 hour to remove moisture and impurities, and then adjusted to 450°C for the MTO reaction. The selectivity for ethylene and propylene and the catalyst life are shown in Table 1:
[0083] Table 1 Selectivity to ethylene and propylene and catalyst life
[0084] Ethylene selectivity (%) Propylene selectivity (%) Lifespan / min Example 1 40.89 39.32 305 Example 2 40.08 39.68 290 Comparative Example 1 37.72 37.29 215 Comparative Example 2 39.24 38.06 255 Comparative Example 3 37.99 38.01 200 Comparative Example 4 38.92 38.21 230 Comparative Example 5 38.51 38.85 250 Comparative Example 6 37.25 37.62 200 Comparative Example 7 38.98 38.23 230
[0085] It can be seen from Table 1 that the raw materials are synthesized according to the molar ratio of aluminum atoms in the aluminum source, phosphorus atoms in the phosphorus source, silicon atoms in the silicon source and triethylamine of 1:0.7:0.1:1.25, the aging time is 20 hours, the crystallization time is 24 hours, and the obtained SAPO-34 molecular sieve has the best catalytic performance.
[0086] Although the principles of the present invention are described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are merely explanations of the exemplary implementations of the present invention, and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute limitations on the scope of the present invention, and any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, fall within the protection scope of the present invention.
Claims
1. A method for preparing a hollow structured SAPO-34 molecular sieve, characterized in that: The following steps are involved: S1: dissolving an aluminum source and a phosphorus source in water and stirring, then adding triethylamine and stirring, and finally adding a silicon source and stirring to obtain a gel; S2: aging, crystallizing, centrifuging, washing and drying the gel to obtain a SAPO-34 molecular sieve having a hollow structure; The molar ratio of aluminum atoms in the aluminum source, phosphorus atoms in the phosphorus source, silicon atoms in the silicon source and triethylamine is 2:1.2-1.8:0.18-0.28:2-3.
2. The method for preparing the hollow structured SAPO-34 molecular sieve according to claim 1, characterized in that: The aging time is 16-22 hours.
3. The method for preparing the hollow structured SAPO-34 molecular sieve according to claim 1, characterized in that: The aging time is 18-20 hours.
4. The method for preparing the hollow structured SAPO-34 molecular sieve according to claim 1, characterized in that: The aging time is 20 hours.
5. The method for preparing the hollow structured SAPO-34 molecular sieve according to claim 1, characterized in that: The aluminum source is selected from one or more of aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite; and / or, The phosphorus source is selected from one or more of orthophosphoric acid and polyphosphoric acid.
6. The method for preparing the hollow structured SAPO-34 molecular sieve according to claim 1, characterized in that: The silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or fumed silica.
7. The method for preparing the hollow structured SAPO-34 molecular sieve according to claim 1, characterized in that: The crystallization temperature is 180-200° C.; and / or, The crystallization time is 1-3 days.
8. A SAPO-34 molecular sieve having a hollow structure, characterized in that: The compound is prepared by the preparation method described in any one of items 1-7.
9. Use of the SAPO-34 molecular sieve with a hollow structure prepared by the preparation method according to any one of claims 1 to 7 or the SAPO-34 molecular sieve with a hollow structure according to claim 8 as a catalyst in methanol to olefins.
10. The use according to claim 9, characterized in that: In the methanol to olefins process, the amount of the hollow structured SAPO-34 molecular sieve is 0.15-0.25 g; and / or, The carrier gas flow rate is 15-25 mL / min; and / or, The injection flow rate of methanol is 0.005-0.015 mL / min; and / or, Mass space velocity is 1h -1 and / or, The temperature of the vaporization chamber is 120-180°C; and / or, The reaction temperature is 400-500°C.