Preparation method of high-crystallinity low-silica-alumina ratio h-zsm-5 molecular sieve by short-time crystallization and application thereof

Abstract

The application discloses a short-time crystallization preparation method of high-crystallinity low-silicon-aluminum ratio H-ZSM-5 molecular sieve and application thereof, and belongs to the field of molecular sieve synthesis. The preparation method comprises the following steps: S1, mixing a silicon source with water to obtain solution A; mixing an aluminum source with water to obtain solution B; mixing an organic amine with water to obtain solution C; S2, adding solution B into solution A, then adding solution C, finally adding seeds, stirring, crystallizing, separating, ion exchanging, drying and roasting to obtain the high-crystallinity low-silicon-aluminum ratio HZSM-5 molecular sieve. The crystallization time is 2-4 h. The HZSM-5 molecular sieve has high crystallinity, the silicon-aluminum ratio is 30-55, the raw material price is low, the amount of organic template agent is small, the synthesis time is very short, the yield is high, the product morphology is hexagonal plate, the particle size is about 2-4 µm, and the HZSM-5 molecular sieve has a good application prospect in the fields of petroleum catalytic cracking and fine chemical industry.

Description

Technical Field

[0001] This application relates to a method for preparing H-ZSM-5 molecular sieve with high crystallinity and low silica-to-alumina ratio by short-time crystallization and its application, belonging to the field of molecular sieve synthesis. Background Technology

[0002] With the growth of global energy demand and the increasing awareness of environmental protection, the need to improve the efficiency of resource utilization from petroleum resources and adopt green synthesis methods is becoming increasingly urgent. The methanol-butene coupling reaction combines the exothermic reaction of methanol-to-olefins (MTO) with the endothermic reaction of butene catalytic cracking, achieving energy complementarity and significantly reducing energy consumption. This not only solves the energy supply problem and simplifies engineering operations but also further improves olefin yield. However, the two reactions differ significantly in reaction conditions and mechanisms. Developing catalysts that are suitable for both feedstocks and reaction conditions, and possess high feedstock conversion rates, olefin selectivity, and catalytic stability, has always been a research hotspot.

[0003] Both technologies can utilize ZSM-5 molecular sieves as reaction catalysts. ZSM-5 molecular sieves possess three-dimensional intersecting ten-membered ring channels with moderate pore size, selectively allowing molecules of specific sizes and shapes to enter the channels for reaction. This facilitates the directional conversion of methanol and butene molecules within the channels, improving olefin selectivity. Furthermore, ZSM-5 molecular sieves exhibit adjustable acidity; their acidic sites can donate protons, promoting the conversion of methanol and butene, accelerating cracking and aromatization reactions, and enhancing reactivity. A low silica-to-alumina ratio increases the number of acidic sites on the molecular sieve surface, increasing acid strength. In reactions requiring strong acid catalysis, such as catalytic cracking, this enhances reactivity and selectivity, benefiting the cracking of large molecules. Highly crystalline ZSM-5 molecular sieves maintain structural integrity and stability under harsh reaction conditions such as high temperature, high pressure, and acidity, extending their service life and reducing replacement costs in industrial production. Moreover, the shortened crystallization time significantly improves synthesis efficiency and reduces energy consumption, making it suitable for rapid industrial production.

[0004] The crystallization time of ZSM-5 molecular sieve is a key parameter in its synthesis process, which is usually affected by factors such as synthesis method, raw material ratio, and temperature, and generally ranges from several hours to several days. CN 101993091 A describes a method for synthesizing ZSM-5 zeolite, which includes: mixing a composite silicon source, an aluminum source, and water, with or without the addition of an inorganic base, and then crystallizing the resulting reaction mixture at 100-200℃ for 8-16 hours. CN 102515197 A describes a ZSM-5 molecular sieve and its preparation method. The preparation method is as follows: A: Dissolve a sodium source in deionized water and add it dropwise to a silicon source, stirring; B: Dissolve an aluminum source in deionized water and add it dropwise to the solution obtained in step A, stirring; C: Dissolve sulfuric acid in deionized water and add it dropwise to the slurry obtained in step B; D: Add S-1 or TS-1 seed crystals and stir to obtain a silica-alumina gel; E: Transfer the silica-alumina gel to a stainless steel high-temperature reactor and crystallize it for 12-36 hours at 150-180℃ and 200-800 rpm, cool it to room temperature, wash it, exchange it with inorganic acid, and wash it again to obtain the ZSM-5 molecular sieve. CN 102745716 A describes a two-stage variable-temperature crystallization process for synthesizing ZSM-5 molecular sieves. Using water-soluble liquid silicon and aluminum sources as raw materials, the silicon source and template agent are mixed with 15-33.3 wt% deionized water (based on the required total deionized water volume) to prepare solution A under dynamic stirring throughout the process. The aluminum source and sulfuric acid are mixed with 24-44.4 wt% water (based on the required total water volume) to prepare solution B. This solution B is slowly added to solution A, and the remaining water is added. After stirring for 0.5-2 hours, the resulting initial gel is added with ZSM-5 seed crystals. The crystallization is then carried out at 80-110℃ for 10-20 hours, followed by further crystallization at 115-130℃ for 10-40 hours. Currently, the crystallization time in the synthesis of ZSM-5 molecular sieves is over 4 hours, which significantly reduces production efficiency, increases costs, and affects crystal performance. Therefore, developing a synthesis method for ZSM-5 in a very short time is crucial. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a high-crystallinity, low-silica-alumina ratio H-ZSM-5 molecular sieve using a short-time crystallization process and its applications. This provides a synthesis method with a short crystallization time, significantly improved synthesis efficiency, reduced energy consumption, and suitability for rapid industrial production. The prepared ZSM-5 molecular sieve can be used in butene catalytic cracking reactions and methanol-butene coupling reactions to produce olefins.

[0006] According to the first aspect of this application, a method for preparing H-ZSM-5 molecular sieve with high crystallinity and low silica-to-alumina ratio by short-time crystallization is provided.

[0007] A method for preparing highly crystallizable, low silica-to-alumina ratio H-ZSM-5 molecular sieve by short-time crystallization, the method comprising: S1 mixes a silicon source with water to obtain solution A; mixes an aluminum source with water to obtain solution B; mixes an organic amine with water to obtain solution C; S2 adds solution B to solution A, then adds solution C, and finally adds seed crystals, stirs, crystallizes, separates, performs ion exchange, dries, and calcines to obtain the high crystallinity, low silica-alumina ratio HZSM-5 molecular sieve.

[0008] Optionally, the silicon source is selected from at least one of water glass, silica sol, and silica. The aluminum source is selected from at least two of aluminum sulfate, boehmite, sodium aluminate, aluminum hydroxide, and aluminum oxide; The organic amine is selected from at least one of n-butylamine, di-n-butylamine, n-hexylamine, and di-n-propylamine.

[0009] Optionally, solution B may also include an acid; said acid is selected from at least one of sulfuric acid, nitric acid, and hydrochloric acid.

[0010] Optionally, the molar ratio of each substance is silicon source: aluminum source: water: organic amine = 35~75:1:900~1500:4~10; The molar amount of silicon source is measured by the molar amount of SiO2 therein; The molar amount of aluminum source is expressed as the molar amount of Al2O3 therein; The molar quantity of water is expressed as its own molar quantity; The molar amount of an organic amine is expressed as its own molar amount.

[0011] Optionally, the molar ratio of the acid to the aluminum source is 10~13:1; The molar amount of acid is expressed as its own molar amount.

[0012] Optionally, the seed crystals are selected from low-silicon ZSM-5 molecular sieves. The silicon-to-aluminum ratio (SiO2 / Al2O3) of the low-silicon ZSM-5 molecular sieve is 40-70.

[0013] Optionally, the silicon-to-aluminum ratio (SiO2 / Al2O3) of the low-silicon ZSM-5 molecular sieve is any value among 40, 45, 50, 55, 60, 65, and 70, or any value between both.

[0014] Optionally, the amount of seed crystal is 3% to 10% of the mass of SiO2 in the silicon source.

[0015] Optionally, the amount of seed crystal is any value among 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10% of the mass of SiO2 in the silicon source, or any value between the two.

[0016] Optionally, the crystallization temperature is 160~190℃; The crystallization time is 2-4 hours.

[0017] Optionally, the crystallization temperature is any value among 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, and 190°C, or a range between any two.

[0018] Optionally, the crystallization time is any value among 2h, 2.5h, 3h, 3.5h, and 4h, or a range between any two.

[0019] Optionally, the drying temperature is 80~120℃; The drying time is 12-48 hours.

[0020] Optionally, the drying temperature is any value among 80°C, 90°C, 100°C, 110°C, and 120°C, or a range between any two.

[0021] Optionally, the drying time is any value among 12h, 24h, 36h, and 48h, or a range between any two.

[0022] Optionally, the calcination temperature is 550~650℃; The roasting time is 3 to 6 hours.

[0023] Optionally, the roasting temperature is any value or a range between 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, and 650°C.

[0024] Optionally, the roasting time is any value among 3h, 4h, 5h, and 6h, or a range between any two.

[0025] In this application, ion exchange is used to obtain hydrogen-form molecular sieves. Ammonium exchange is typically employed, and the specific operation can be carried out using conventional methods found in existing technologies.

[0026] In one preferred embodiment, the preparation method includes: (1) Mix the silicon source with water to obtain solution A; (2) Mix the aluminum source with water to obtain solution B; (3) Mix the organic amine with water to obtain solution C; (4) Add solution B to solution A, then add solution C, and finally add seed crystals. Stir, put into a polytetrafluoroethylene reactor, crystallize for 2-4 h, cool, centrifuge, ion exchange, dry, and calcine to obtain the high crystallinity HZSM-5 molecular sieve.

[0027] As one specific implementation method, the preparation method includes: (1) Water glass and water are mixed to form solution A; (2) Aluminum sulfate, aluminum hydroxide and sulfuric acid dissolve in water to form solution B; (3) Organic amines and water are mixed to form solution C; and (4) Add solution B to solution A, then add solution C, and finally add seed crystals to form a ZSM-5 molecular sieve gel system. Stir evenly, crystallize, cool and collect the lower solid layer, perform ion exchange, dry and calcine to obtain H-type ZSM-5 molecular sieve.

[0028] Optionally, the modulus of the water glass is 2.3 to 3.5.

[0029] Optionally, the modulus of the water glass is any value among 2.6, 2.7, 3.0, 3.2, and 3.5, or a range between any two.

[0030] Optionally, the molar ratio of the substances is: 35-75SiO2:Al2O3:900-1500H2O:10-13H2SO4:4-10organicamines.

[0031] According to a second aspect of this application, a high-crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve is provided.

[0032] The high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve prepared by the above-described preparation method.

[0033] Optionally, the silicon-to-aluminum ratio of the high crystallinity, low silicon-to-aluminum ratio H-ZSM-5 molecular sieve is 30 to 55.

[0034] Optionally, the crystallinity of the high crystallinity, low silica-alumina ratio H-ZSM-5 molecular sieve is 85%~100%.

[0035] Optionally, the particle size of the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve is 2~20µm.

[0036] Optionally, the specific surface area of ​​the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve is 320~380 m². 2 / g.

[0037] Optionally, the pore volume of the highly crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve is 0.18~0.22 cm³. 3 / g.

[0038] The obtained high-crystallinity, low-silicon-aluminum ratio H-ZSM-5 molecular sieve product has a hexagonal plate-like morphology with a particle size of approximately 2~4µm.

[0039] According to a third aspect of this application, an application of a highly crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve in the catalytic cracking reaction of butene is provided.

[0040] The application of the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve described above in the catalytic cracking reaction of butene.

[0041] According to the fourth aspect of this application, an application of a highly crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve in the coupling reaction of methanol and butene to produce olefins is provided.

[0042] The application of the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve described above in the coupling reaction of methanol and butene to produce olefins.

[0043] The beneficial effects that this application can produce include: The method for preparing high-crystallinity, low-silica-alumina ratio H-ZSM-5 molecular sieves via short-time crystallization and its applications provided in this application allow for the synthesis of H-ZSM-5 molecular sieves via extremely short-time crystallization, significantly reducing production costs. Furthermore, it requires less template agent, uses inexpensive raw materials, achieves high yields, and features a simple operation process that is easy to control during production. The prepared H-ZSM-5 molecular sieve exhibits a low silica-alumina ratio and high crystallinity, showing promising application prospects in petroleum catalytic cracking and fine chemical industries. Attached Figure Description

[0044] Figure 1 The XRD pattern of H-ZSM-5 molecular sieve in Example 1; Figure 2 This is a SEM image of the H-ZSM-5 molecular sieve from Example 1; Figure 3 This is a SEM image of the H-ZSM-5 molecular sieve from Example 2; Figure 4 This is a SEM image of the H-ZSM-5 molecular sieve from Example 3; Figure 5 This is a SEM image of the H-ZSM-5 molecular sieve from Example 4; Figure 6 The image shows the SEM image of the H-ZSM-5 molecular sieve from Example 5. Detailed Implementation

[0045] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0046] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0047] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0048] The analysis method in the embodiments of this application is as follows: The X-ray diffraction (XRD) analysis was performed using a PANalytical instrument with a Cu target, a tube voltage of 40 kV, and a tube current of 40 mA.

[0049] The scanning electron microscope (SEM) instrument used was a HITACHI TM4000.

[0050] The specific surface area and pore volume were measured using an ASAP 2460 instrument. The pretreatment conditions were 100°C for 30 min and 350°C for 3.5 h.

[0051] The seed crystals used in this example are low-silica ZSM-5 molecular sieves, which were self-made. The specific preparation method is as follows: 1) Add 19g of deionized water and 24g of water glass (modulus 2.7) to a 100mL stainless steel synthesis reactor and stir for 10min; 2) Add 0.5g aluminum sulfate, 0.3g aluminum hydroxide, 15g water, and 3.50g sulfuric acid (98%) to beaker A, and stir well; 3) Add 15g of deionized water and 1.2g of n-butylamine to beaker B, and stir well; 4) While stirring, slowly add the solution from beaker A dropwise into the vessel, then add the solution from beaker B dropwise into the vessel; 5) Continue stirring for 1 hour to obtain the initial reaction gel. After sealing, heat to 165℃ and allow to crystallize dynamically for 4 hours. 6) After crystallization, centrifuge, wash the filter cake once at room temperature, then add 100.00g of 0.65mol / L ammonium chloride solution, stir at 80℃ for 2h, repeat twice, centrifuge, and wash the filter cake three times at room temperature. 7) The filter cake is dried at 120℃ and calcined at 650℃ for 3 hours to obtain H-ZSM-5 molecular sieve. The silicon-to-aluminum ratio (SiO2 / Al2O3) of H-ZSM-5 molecular sieve is 56 mol / mol.

[0052] Example 1 1) Add 6.5g of deionized water and 17.20g of water glass (modulus 2.7) to a 100mL stainless steel synthesis reactor and stir for 10min; 2) Add 0.35g aluminum sulfate, 0.25g aluminum hydroxide, 10g water, and 2.60g sulfuric acid (98%) to beaker A, and stir until well mixed; 3) Add 10g of deionized water and 0.70g of n-butylamine to beaker B, and stir well; 4) While stirring, slowly add the solution from beaker A to the reactor, then add the solution from beaker B to the reactor, and add 0.50g of seed crystals; 5) Continue stirring for 2 hours to obtain the initial reaction gel. After sealing, heat to 180℃ and allow to crystallize dynamically for 2 hours. 6) After crystallization, centrifuge, wash the filter cake once at room temperature, then add 100.00g of 0.65mol / L ammonium chloride solution, stir at 90℃ for 2h, repeat twice, centrifuge, and wash the filter cake three times at room temperature. 7) The filter cake was dried at 120℃ and calcined at 650℃ for 3 hours to obtain H-ZSM-5 molecular sieve. The silicon-to-aluminum ratio (SiO2 / Al2O3) of H-ZSM-5 molecular sieve is 51 mol / mol, and its specific surface area is 367.97 m². 2 / g, pore volume 0.20cm 3 / g, its SEM image is as follows Figure 2 As shown, the particles are hexagonal plates with a diameter of approximately 2 µm. Their XRD pattern is as follows. Figure 1 As shown, the synthesized molecular sieve is a pure phase and has high crystallinity.

[0053] Example 2 1) Add 20.50g of deionized water and 18.20g of water glass (modulus 2.6) to a 100mL stainless steel synthesis reactor and stir for 10min; 2) Add 0.35g aluminum sulfate, 0.30g aluminum hydroxide, 10g water, and 2.20g sulfuric acid (98%) to beaker A, and stir until well mixed; 3) Add 1.30g of di-n-butylamine and 20g of deionized water to beaker B, and stir well; 4) While stirring, slowly add the solution from beaker A to the reactor, then add the solution from beaker B to the reactor, and add 0.52g of seed crystals; 5) Continue stirring for 2 hours to obtain the initial reaction gel. After sealing, heat to 180℃ and allow to crystallize dynamically for 2 hours. 6) After crystallization, centrifuge, wash the filter cake once at room temperature, then add 100.00g of 0.70mol / L ammonium chloride solution, stir at 90℃ for 2h, repeat twice, centrifuge, and wash the filter cake three times at room temperature. 7) The filter cake was dried at 120℃ and calcined at 650℃ for 3 hours to obtain H-ZSM-5 molecular sieve. The silicon-to-aluminum ratio (SiO2 / Al2O3) of H-ZSM-5 molecular sieve is 33 mol / mol, and its specific surface area is 347.66 m². 2 / g, pore volume 0.19cm 3 / g, its SEM image is as follows Figure 3 As shown, the particles are hexagonal plates with a diameter of approximately 4µm.

[0054] Example 3 Based on Example 2, di-n-butylamine was replaced with di-n-propylamine at a dosage of 1.05 g, while the remaining raw material amounts and conditions remained unchanged. The silicon-to-aluminum ratio (SiO2 / Al2O3) of the ZSM-5 molecular sieve was 35 mol / mol, and its specific surface area was 335.15 m². 2 / g, pore volume 0.19cm 3 / g, its SEM image is as follows Figure 4 As shown, the particles are hexagonal plates with a diameter of approximately 2µm.

[0055] Example 4 1) Add 10.5g of deionized water and 18.20g of water glass (modulus 2.6) to a 100mL stainless steel synthesis reactor and stir for 10min; 2) Add 0.51g aluminum sulfate, 0.24g aluminum hydroxide, 10g water, and 2.20g sulfuric acid (98%) to beaker A, and stir until well mixed; 3) Add 0.75g of n-butylamine and 10g of deionized water to beaker B, and stir well; 4) While stirring, slowly add the solution from beaker A to the reactor, then add the solution from beaker B to the reactor, and add 0.50g of seed crystals; 5) Continue stirring for 2 hours to obtain the initial reaction gel. After sealing, heat to 180℃ and allow to crystallize dynamically for 3 hours. 6) After crystallization, centrifuge and wash the filter cake 4 times at room temperature, each time for 10 minutes, until the pH of the centrifuged liquid is 7-8. 7) The filter cake is dried at 100℃ and calcined at 550℃ for 3 hours to obtain Na-ZSM-5 molecular sieve; 8) Add Na-ZSM-5 molecular sieve to the flask, then add 50g of 0.65mol / L ammonium chloride solution, and stir at 90℃ for 2h; 9) Centrifuge, wash the filter cake three times at room temperature, and beat for 10 minutes each time; 10) The filter cake is dried at 100℃ and calcined at 550℃ for 3 hours to obtain H-ZSM-5 molecular sieve. The silicon-to-aluminum ratio (SiO2 / Al2O3) of H-ZSM-5 molecular sieve is 32 mol / mol, and its specific surface area is 356.84 m². 2 / g, pore volume 0.20cm 3 / g, its SEM image is as follows Figure 5 As shown, the particles are hexagonal plates with a diameter of approximately 2µm.

[0056] Example 5 1) Add 21.00g of deionized water and 17.5g of water glass (modulus 3.2) to a 100mL stainless steel synthesis reactor and stir for 10min; 2) Add 0.52g aluminum sulfate, 0.25g aluminum hydroxide, 10g water, and 1.75g ​​sulfuric acid (98%) to beaker A, and stir well; 3) Add 20g of deionized water and 0.72g of n-butylamine to beaker B, and stir well; 4) While stirring, slowly add the solution from beaker A to the reactor, then add the solution from beaker B to the reactor, and add 0.51g of seed crystals; 5) Continue stirring for 2 hours to obtain the initial reaction gel. After sealing, heat to 180℃ and allow to crystallize dynamically for 3 hours. 6) After crystallization, centrifuge, wash the filter cake once at room temperature, then add 100.00g of 0.65mol / L ammonium chloride solution, stir at 90℃ for 2h, repeat twice, centrifuge, and wash the filter cake three times at room temperature. 7) The filter cake was dried at 120℃ and calcined at 650℃ for 3 hours to obtain H-ZSM-5 molecular sieve. The silicon-to-aluminum ratio (SiO2 / Al2O3) of H-ZSM-5 molecular sieve is 42 mol / mol, and its specific surface area is 374.32 m². 2 / g, pore volume 0.20cm 3 / g, its SEM image is as follows Figure 6 As shown, the particles are hexagonal plates with a diameter of approximately 2µm.

[0057] Example 6 The methanol-butene coupling conversion reaction was carried out in a micro fixed-bed reactor. The ZSM-5 molecular sieve powder obtained in Example 1 was compressed into tablets using a tablet press, then ground, and sieved. 200 mg of the 20-40 mesh sieve sample was collected and loaded into the fixed-bed reactor. The quartz tube microreactor had an inner diameter of 6 mm, and the reaction was carried out in the range of 160–650 °C. A nitrogen-carrying methanol-saturated vapor was used as the feed gas. This gas stream was thoroughly mixed with butene obtained directly from a gas cylinder before entering the reactor for reaction. The reaction products were introduced into an online gas chromatograph equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID) throughout the reaction. After the reaction started, ethylene and propylene were clearly observed in the gas chromatograph.

[0058] 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 high-crystallinity, low-silica-alumina ratio H-ZSM-5 molecular sieve by short-time crystallization, characterized in that, The preparation method includes: S1 mixes a silicon source with water to obtain solution A; mixes an aluminum source with water to obtain solution B; mixes an organic amine with water to obtain solution C; S2 adds solution B to solution A, then adds solution C, and finally adds seed crystals, stirs, crystallizes, separates, performs ion exchange, dries, and calcines to obtain the high crystallinity, low silica-alumina ratio HZSM-5 molecular sieve.

2. The preparation method according to claim 1, characterized in that, The silicon source is selected from at least one of water glass, silica sol, and silica. The aluminum source is selected from at least two of aluminum sulfate, boehmite, sodium aluminate, aluminum hydroxide, and aluminum oxide; The organic amine is selected from at least one of n-butylamine, di-n-butylamine, n-hexylamine, and di-n-propylamine; Preferably, solution B further includes an acid; the acid is selected from at least one of sulfuric acid, nitric acid, and hydrochloric acid.

3. The preparation method according to claim 1, characterized in that, The molar ratio of each substance is silicon source: aluminum source: water: organic amine = 35~75:1:900~1500:4~10; The molar amount of silicon source is measured by the molar amount of SiO2 therein; The molar amount of aluminum source is expressed as the molar amount of Al2O3 therein; The molar quantity of water is expressed as its own molar quantity; The molar amount of an organic amine is expressed as its own molar amount; Preferably, the molar ratio of the acid to the aluminum source is 10~13:1; The molar amount of acid is expressed as its own molar amount.

4. The preparation method according to claim 1, characterized in that, The seed crystals are selected from low-silicon ZSM-5 molecular sieves; Preferably, the amount of seed crystal is 3% to 10% of the mass of SiO2 in the silicon source.

5. The preparation method according to claim 1, characterized in that, The crystallization temperature is 160~190℃; The crystallization time is 2-4 hours.

6. The preparation method according to claim 1, characterized in that, The drying temperature is 80~120℃; The drying time is 12-48 hours; Preferably, the calcination temperature is 550~650℃; The roasting time is 3 to 6 hours.

7. The high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve prepared by the preparation method according to any one of claims 1 to 6.

8. The high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve according to claim 7, characterized in that, The silicon-to-aluminum ratio of the highly crystallinity, low silicon-to-aluminum ratio H-ZSM-5 molecular sieve is 30~55; The crystallinity of the high-crystallinity, low-silicon-aluminum ratio H-ZSM-5 molecular sieve is 85%~100%; Preferably, the particle size of the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve is 2~20µm; The specific surface area of ​​the highly crystalline, low silica-to-alumina ratio H-ZSM-5 molecular sieve is 320~380 m². 2 / g; The pore volume of the highly crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve is 0.18~0.22 cm³. 3 / g.

9. The application of the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve as described in claim 7 or 8 in the catalytic cracking reaction of butene.

10. The application of the high crystallinity, low silica-to-alumina ratio H-ZSM-5 molecular sieve according to claim 7 or 8 in the reaction of methanol and butene to produce olefins.

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