Preparation method of composite modified hierarchical pore nanosheet ZSM-5 catalyst, application of composite modified hierarchical pore nanosheet ZSM-5 catalyst in toluene-methanol alkylation reaction and reaction equipment

Abstract

The embodiment of the invention provides a preparation method of a composite modified hierarchical pore nanosheet ZSM-5 catalyst, application in toluene methanol alkylation reaction and reaction equipment, and the preparation method comprises the following steps: S1, hydrolyzing a silicon source, an aluminum source, a template agent, a mineralizing agent and a solvent, and crystallizing in a crystallization kettle after hydrolysis; and S2, drying the crystals in the crystallization kettle obtained in the step S1 to obtain the nanosheet ZSM-5 catalyst, and S3, mixing the nanosheet-shaped ZSM-5 catalyst obtained in the step S2 with an alkali solution, separating from the alkali solution, washing to be neutral, and drying to obtain the hierarchical pore nanosheet-shaped ZSM-5 catalyst, relates to the field of catalysts. According to the method, a high-concentration alkali treatment process is additionally added in a ZSM-5 catalyst preparation process, so that not only can the selectivity be improved, but also the activity and the stability are improved. And the toluene-methanol alkylation reaction catalyst with excellent performance can be obtained by matching compound modification after the alkali treatment process.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and particularly to a preparation method of a composite modified hierarchical pore nano-sheet ZSM-5 catalyst, its application in the alkylation reaction of toluene with methanol, and reaction equipment. Background Art

[0002] Developing a process for producing p-xylene from non-petroleum resources can not only optimize the energy structure but also achieve the rational allocation of fossil resources, which has important strategic significance. Due to its excellent shape selectivity, ZSM-5 molecular sieve is widely used in the alkylation reaction of toluene with methanol to produce p-xylene. However, it is difficult to balance stability, activity (toluene conversion rate), and selectivity (especially p-xylene selectivity) in the existing technology, and a technological breakthrough is urgently needed.

[0003] Research shows that improving the diffusion performance of ZSM-5 is an important means to enhance stability and activity. For example, various synthesis methods of hierarchical pore nano-ZSM-5 have been reported (such as US11097262B2, US8951498B2, etc.). These methods significantly improve the anti-coking ability of the catalyst and the accessibility of acid sites by introducing a hierarchical pore structure, thereby enhancing the stability and activity of the catalyst. However, evidence shows that this hierarchical pore treatment sometimes impairs the selectivity of p-xylene (ChemComm, 2013, 49, 10584-10586). On the other hand, certain progress has been made in the research on improving p-xylene selectivity through modification means (such as phosphorus modification, zinc modification, etc.) (such as US4250345A, CN103113182A). However, the introduction of modifiers often leads to pore blockage, significantly reducing the activity and stability of the catalyst.

[0004] Currently, there is no reported research on improving p-xylene selectivity during the hierarchical pore treatment of nano-scale catalysts. This indicates that it is difficult to balance stability and selectivity in the existing technology, and new solutions are urgently needed. The present invention proposes a new method: first, prepare a nano-sheet ZSM-5 catalyst to improve molecular diffusion performance; then introduce a hierarchical pore structure through alkali treatment to further enhance the diffusion performance; finally, further optimize the selectivity of p-xylene through appropriate modification means (such as silicon or phosphorus modification). This method aims to simultaneously enhance the stability and selectivity of the catalyst, filling the gap in the existing technology. Summary of the Invention

[0005] According to an embodiment of the present invention, there is provided a preparation method of a composite modified hierarchical pore nano-sheet ZSM-5 catalyst, its application in the alkylation reaction of toluene with methanol, and reaction equipment. It is used to solve the technical problems existing in the above background.

[0006] In the first aspect of the present invention, a method for preparing a composite modified hierarchical pore nano-sheet ZSM-5 catalyst is provided, comprising the following steps:

[0007] S1, hydrolyze a silicon source, an aluminum source, a template agent, a mineralizing agent and a solvent, and after hydrolysis, carry out crystallization in a crystallization kettle;

[0008] S2, dry the crystals in the crystallization kettle obtained in step S1 to obtain a nano-sheet ZSM-5 catalyst;

[0009] S3, mix the nano-sheet ZSM-5 catalyst obtained in step S2 with an alkali solution and then separate it from the alkali solution, wash it to neutrality and carry out a drying treatment to obtain a hierarchical pore nano-sheet ZSM-5 catalyst;

[0010] S4, carry out shaping treatment on the hierarchical pore nano-sheet ZSM-5 catalyst obtained in step S3, and carry out ion exchange on the hierarchical pore nano-sheet ZSM-5 catalyst after the shaping treatment is completed;

[0011] S5, impregnate the ion-exchanged hierarchical pore nano-sheet ZSM-5 catalyst obtained in step S4 with a cyclohexane solution of tetraethyl orthosilicate to obtain a silicon-modified hierarchical pore nano-sheet ZSM-5 catalyst; impregnate the obtained silicon-modified hierarchical pore nano-sheet ZSM-5 catalyst with an aqueous solution of ammonium dihydrogen phosphate to obtain a silicon and phosphorus-modified hierarchical pore nano-sheet ZSM-5 catalyst;

[0012] S6, carry out metal modification on the silicon and phosphorus-modified hierarchical pore nano-sheet ZSM-5 catalyst obtained in step S5, and then obtain a composite modified hierarchical pore nano-sheet ZSM-5 catalyst after a drying treatment.

[0013] In the second aspect of the present invention, an application of a composite modified hierarchical pore nano-sheet ZSM-5 catalyst in the toluene methanol alkylation reaction is provided, comprising the following steps:

[0014] A1, load the composite modified hierarchical pore nano-sheet ZSM-5 catalyst obtained in step S6 into the constant temperature section of a fixed bed reactor;

[0015] A2, fill inert porcelain balls at both the upper and lower parts of the constant temperature section of the fixed bed reactor;

[0016] A3, gradually heat the fixed bed reactor to 300-600 degrees Celsius in a hydrogen environment, with a hydrogen / hydrocarbon molar ratio of 0.2-10 and a reaction pressure of 0.1-3.0 MPa;

[0017] A4, feed a mixed solution of toluene and methanol with a molar ratio of 1-10 into a vaporizer at a feed rate of 0.5-10 h-1 in terms of mass space velocity;

[0018] A5, feeding a feed at a water / hydrocarbon molar ratio of 0.2-10 into a vaporizer, mixing uniformly in the vaporizer and then entering a reactor;

[0019] A6, the reactor product is separated into a gas phase product and a liquid phase product by a cold trap, and the gas phase product and the liquid phase product are subjected to chromatographic analysis respectively.

[0020] In a third aspect of the present invention, there is provided a preparation device for a composite modified multi-level porous nano-sheet ZSM-catalyst, comprising a frame, a tank and an auxiliary mechanism, wherein the tank is connected to the frame, and the auxiliary mechanism is arranged inside the tank;

[0021] The auxiliary mechanism includes a filter assembly, a plugging, a branch pipe, a waste liquid pipe, a heating wire, a pump body and a pad;

[0022] The filter assembly is slidably connected to the inner wall of the tank body, the bottom of the filter assembly is connected to the plug, the outer wall of the plug is gap-matched with the inner wall of the branch pipe, the branch pipe is connected to the waste liquid pipe, the waste liquid pipe passes through the tank body, the branch pipe passes through the pad, the pad is connected to the inner wall of the tank body, the heating wire is arranged between the pad and the filter assembly, and the bottom of the pad is connected to the output end of the pump body.

[0023] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0024] 1. A method for preparing a composite modified multi-level porous nano-sheet ZSM-5 catalyst provided by the present invention, its application in the alkylation reaction of toluene and methanol, and a reaction device. In the process of preparing the ZSM-5 catalyst, the method adds an additional high-concentration alkali treatment process, which can not only improve the selectivity, but also improve the activity and stability. The alkali treatment process is followed by a composite modification to obtain a toluene and methanol reaction catalyst with excellent performance. The method improves the selectivity of p-xylene while enhancing the diffusion performance. The method further uses a variety of elements to modify the nano-sheet ZSM-5 catalyst by alkali treatment, and obtains a composite modified multi-level porous nano-sheet ZSM-5 catalyst. Under the same p-xylene selectivity conditions, the catalyst stability is five times that of the traditional micron-grade ZSM-5. This provides a new idea for taking into account both high stability and high selectivity in the alkylation reaction of toluene and methanol.

[0025] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In conjunction with the accompanying drawings and with reference to the following detailed description, the above and other features, advantages, and aspects of the embodiments of the present invention will become more apparent. In the drawings, the same or similar reference numerals denote the same or similar elements, where:

[0027] Figure 1 Shows the XRD pattern of the preparation method of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0028] Figure 2 Shows the scanning electron microscope image of the example in the preparation method of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0029] Figure 3 Shows the scanning electron microscope image of the control example in the preparation method of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0030] Figure 4 Shows the Ar adsorption-desorption curve of the preparation method of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0031] Figure 5 Shows the schematic connection structure diagram of the preparation equipment of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0032] Figure 6 Shows the exploded view of the preparation equipment of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0033] Figure 7 Shows the schematic connection structure diagram of the stirring assembly of the preparation equipment of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0034] Figure 8 Shows the exploded view of the stirring assembly of the preparation equipment of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0035] Figure 9 Shows the exploded view of the flattening assembly of the preparation equipment of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0036] Figure 10 Shows the schematic connection structure diagram of the flattening assembly of the preparation equipment of the composite-modified hierarchical pore nanosheet ZSM-5 catalyst according to an embodiment of the present invention;

[0037] Figure 11Schematic diagram of the connection structure of the back plate and the rotating plate of the preparation equipment of the composite modified hierarchical pore nano-sheet ZSM-5 catalyst according to an embodiment of the present invention;

[0038] Figure 12 Schematic diagram of the connection structure of the linkage mechanism of the preparation equipment of the composite modified hierarchical pore nano-sheet ZSM-5 catalyst according to an embodiment of the present invention;

[0039] Figure 13 Partial schematic diagram of the linkage mechanism of the preparation equipment of the composite modified hierarchical pore nano-sheet ZSM-5 catalyst according to an embodiment of the present invention;

[0040] Figure 14 Schematic diagram of the connection structure of the drying mechanism of the preparation equipment of the composite modified hierarchical pore nano-sheet ZSM-5 catalyst according to an embodiment of the present invention. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] Example 1, S1: The molar ratio of tetraethyl orthosilicate, aluminum chloride, tetrapropylammonium hydroxide, ammonium fluoride and water, which represent the silicon source, aluminum source, template agent, mineralizing agent and solvent, is 1:0.0025:0.40:0.8:34. Take 12.49 grams of tetrapropylammonium hydroxide aqueous solution (25 wt%) (actually containing 3.12 grams of tetrapropylammonium hydroxide), add 8 grams of tetraethyl orthosilicate and 0.01 gram of seed crystal, and stir at 40 °C until the tetraethyl orthosilicate is completely hydrolyzed, marked as solution A. Dissolve 0.05 gram of aluminum chloride hexahydrate in 4.5 grams of water, add it to solution A and continue stirring for 2 hours. Finally, add 1.14 grams of ammonium fluoride and 4 grams of water to the above solution, stir for 1 hour, then load it into a crystallization kettle and crystallize at 160 °C for 44 hours.

[0043] S2: Cool and wash the crystallized substance in step S1 to neutral, calcine it at 540 °C for 6 hours, and finally obtain a nano-sheet ZSM-5 catalyst with a nano-sheet layer thickness of 30 nanometers and a molar ratio of silicon oxide to aluminum oxide of 400. The obtained catalyst is marked as NZ.

[0044] S3: Take 5.0 g of the catalyst NZ in step S2 and add it to 25.0 g of an aqueous sodium hydroxide solution (0.45 mol / L). The alkali treatment temperature is 60 °C. After stirring or standing the resulting mixed solution (for 0.1 h), perform solid-liquid separation. After separation, dry and calcine to obtain a hierarchical porous nanosheet ZSM-5 catalyst, where the calcination time is 4 h and the temperature is 540 °C.

[0045] S4: Shape the catalyst obtained in step S3 using an alumina binder. The mass ratio of the binder in the shaped catalyst is 5%. Ion-exchange the resulting catalyst with an aqueous ammonium nitrate solution (1.0 mol / L) at 80 °C three times, and then calcine at 540 °C for 4 h. Finally, a hierarchical porous nanosheet catalyst can be obtained, and the resulting catalyst is labeled NZ-1.2M.

[0046] S5: Take the catalyst NZ-1.2M in step S4 and impregnate the surface of the catalyst with a cyclohexane solution of tetraethyl orthosilicate by the equal-volume impregnation method (the loading amount of silicon is 0.5 wt% based on SiO2). Let it stand at room temperature for 4 h, dry at 80 °C for 4 h, and then calcine at 540 °C for 4 h. Finally, a silicon-modified hierarchical porous nanosheet ZSM-5 catalyst can be obtained, and the resulting catalyst is labeled NZ-1.2M-S.

[0047] Take the catalyst NZ-1.2M-S and impregnate the surface of the catalyst with an aqueous solution of ammonium dihydrogen phosphate by the equal-volume impregnation method (the loading amount of phosphorus is 0.1 wt% based on P2O5). Let it stand at room temperature for 4 h, dry at 80 °C for 4 h, and then calcine at 540 °C for 4 h. Finally, a silicon- and phosphorus-modified hierarchical porous nanosheet ZSM-5 catalyst can be obtained, and the resulting catalyst is labeled NZ-1.2M-SP.

[0048] S6: Take the catalyst NZ-1.2M-SP in step S5 and impregnate the surface of the obtained catalyst with a platinum precursor solution (the loading amount of platinum is 0.01 wt% based on Pt). Let it stand at room temperature for 24 h, dry at 150 °C for 12 h, and then calcine at 400 °C for 4 h. Finally, a hierarchical porous nanosheet ZSM-5 catalyst modified with platinum metal composite can be obtained, and the resulting catalyst is labeled NZ-1.2M-M.

[0049] Among them, step S6 can also be: taking the catalyst NZ-1.2M-SP in step S5, impregnating the nickel precursor solution onto the surface of the obtained catalyst (the loading amount of nickel is 0.1 wt% in terms of Ni), standing at room temperature for 24 hours, drying at 150 °C for 12 hours, and then calcining at 400 °C for 4 hours. Finally, a hierarchically porous nanosheet ZSM-5 catalyst modified with nickel metal composite can be obtained, and the obtained catalyst is labeled as NZ-1.2M-N.

[0050] Example 2, S1: The molar ratio of tetraethyl orthosilicate, aluminum chloride, tetrapropylammonium hydroxide, ammonium fluoride and water, which represent the silicon source, aluminum source, template agent, mineralizer and solvent, is 1:0.05:0.05:0.10:10. 1.56 g of tetrapropylammonium hydroxide aqueous solution (25 wt%) (containing 0.39 g of tetrapropylammonium hydroxide) was added with 8 g of tetraethyl orthosilicate and 0.01 g of seed crystal, and stirred at 40 °C until the tetraethyl orthosilicate was completely hydrolyzed, labeled as solution A. 0.95 g of aluminum chloride hexahydrate was dissolved in 1.5 g of water, and solution A was added and stirred for another 2 hours. 0.143 g of ammonium fluoride was dissolved in 0.5 g of water, added to the above solution, stirred for 1 hour, and then loaded into a crystallization kettle and crystallized at 190 °C for 96 hours.

[0051] S2: The crystallized material in step S1 was cooled and washed to neutral, and calcined at 540 °C for 6 hours. Finally, a nanosheet ZSM-5 catalyst with a nanosheet layer thickness of 300 nm and a molar ratio of silicon oxide to aluminum oxide of 20 was obtained, and the obtained catalyst was labeled as NZ.

[0052] S3: Take 5.0 g of the catalyst NZ in step S2 and add it to 25.0 g of sodium hydroxide aqueous solution (0.1 mol / L). The alkali treatment temperature is 95 °C, and the obtained mixed solution is stirred or left standing (for 20 hours). Solid-liquid separation is carried out, and after separation, it is dried and calcined to obtain a hierarchically porous nanosheet ZSM-5 catalyst, where the calcination time is 4 hours and the temperature is 540 °C.

[0053] S4: The catalyst obtained in step S3 was shaped using an alumina binder. The mass ratio of the binder in the shaped catalyst is 80%. The obtained catalyst was ion-exchanged with ammonium nitrate aqueous solution (1.0 mol / L) three times at 80 °C, and then calcined at 540 °C for 4 hours. Finally, a hierarchically porous nanosheet catalyst was obtained, and the obtained catalyst was labeled as NZ-1.2M.

[0054] S5: Take the catalyst NZ-1.2M in step S4, and by the method of equal-volume impregnation, impregnate the cyclohexane solution of tetraethyl orthosilicate onto the surface of the catalyst (the loading amount of silicon is 30 wt% calculated as SiO2). Let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon-modified hierarchical porous nanosheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-1.2M-S.

[0055] Take the catalyst NZ-1.2M-S, and by the method of equal-volume impregnation, impregnate the aqueous solution of ammonium dihydrogen phosphate onto the surface of the catalyst (the loading amount of phosphorus is 20 wt% calculated as P2O5). Let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon- and phosphorus-modified hierarchical porous nanosheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-1.2M-SP.

[0056] S6: Take the catalyst NZ-1.2M-SP in step S5, and impregnate the platinum precursor solution onto the surface of the obtained catalyst (the loading amount of platinum is 2 wt% calculated as Pt). Let it stand at room temperature for 24 hours, dry it at 150 °C for 12 hours, and then calcine it at 400 °C for 4 hours. Finally, a hierarchical porous nanosheet ZSM-5 catalyst modified by composite with metallic platinum can be obtained, and the obtained catalyst is labeled as NZ-1.2M-M.

[0057] Among them, step S6 can also be: Take the catalyst NZ-1.2M-SP in step S5, and impregnate the nickel precursor solution onto the surface of the obtained catalyst (the loading amount of nickel is 30 wt% calculated as Ni). Let it stand at room temperature for 24 hours, dry it at 150 °C for 12 hours, and then calcine it at 400 °C for 4 hours. Finally, a hierarchical porous nanosheet ZSM-5 catalyst modified by composite with metallic nickel can be obtained, and the obtained catalyst is labeled as NZ-1.2M-N.

[0058] Example 3, S1: The molar ratio of tetraethyl orthosilicate, aluminum chloride, tetrapropylammonium hydroxide, ammonium fluoride, and water, which represent the silicon source, aluminum source, template agent, mineralizing agent, and solvent respectively, is 1:0.02:0.80:0.50:100. Take 24.96 g of tetrapropylammonium hydroxide aqueous solution (25 wt%) (containing 6.24 g of tetrapropylammonium hydroxide), add 8 g of tetraethyl orthosilicate and 0.01 g of seed crystal, stir at 40 °C until the tetraethyl orthosilicate is completely hydrolyzed, and label it as solution A. Dissolve 0.926 g of aluminum chloride hexahydrate in 15 g of water, add solution A and continue stirring for 2 hours. Dissolve 0.711 g of ammonium fluoride in 10 g of water, add the above solution, stir for 1 hour, and then load it into a crystallization kettle and crystallize at 150 °C for 12 hours.

[0059] S2: Cool and wash the crystallized substance in step S1 to neutrality, and then calcine it at 540 °C for 6 hours. Finally, a nano-sheet ZSM-5 catalyst with a nano-sheet layer thickness of 300 nm and a molar ratio of silica to alumina of 50 can be obtained. The obtained catalyst is labeled as NZ.

[0060] S3: Take 5.0 g of the catalyst NZ in step S2 and add it to 25.0 g of an aqueous sodium hydroxide solution (2 mol / L). The alkali treatment temperature is 20 °C. After stirring or standing the obtained mixed solution (for 5 hours), perform solid-liquid separation. After separation, dry and calcine to obtain a hierarchical porous nano-sheet ZSM-5 catalyst, where the calcination time is 4 hours and the temperature is 540 °C.

[0061] S4: Shape the catalyst obtained in step S3 using an alumina binder. The mass ratio of the binder in the shaped catalyst is 55%. Exchange the obtained catalyst with an ammonium nitrate aqueous solution (1.0 mol / L) at 80 °C three times, and then calcine it at 540 °C for 4 hours. Finally, a hierarchical porous nano-sheet catalyst can be obtained. The obtained catalyst is labeled as NZ-1.2M.

[0062] S5: Take the catalyst NZ-1.2M in step S4 and impregnate the surface of the catalyst with a cyclohexane solution of tetraethyl orthosilicate by the equal-volume impregnation method (the loading amount of silicon calculated as SiO2 is 21 wt%). Let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon-modified hierarchical porous nano-sheet ZSM-5 catalyst can be obtained. The obtained catalyst is labeled as NZ-1.2M-S.

[0063] Take the catalyst NZ-1.2M-S and impregnate the surface of the catalyst with an aqueous solution of ammonium dihydrogen phosphate by the equal-volume impregnation method (the loading amount of phosphorus calculated as P2O5 is 12 wt%). Let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon and phosphorus composite-modified hierarchical porous nano-sheet ZSM-5 catalyst can be obtained. The obtained catalyst is labeled as NZ-1.2M-SP.

[0064] S6: Take the catalyst NZ-1.2M-SP in step S5 and impregnate the surface of the obtained catalyst with a platinum precursor solution (the loading amount of platinum calculated as Pt is 1.5 wt%). Let it stand at room temperature for 24 hours, dry it at 150 °C for 12 hours, and then calcine it at 400 °C for 4 hours. Finally, a hierarchical porous nano-sheet ZSM-5 catalyst modified with platinum metal composite can be obtained. The obtained catalyst is labeled as NZ-1.2M-M.

[0065] Among them, step S6 can also be: taking the catalyst NZ-1.2M-SP in step S5, impregnating the nickel precursor solution onto the surface of the obtained catalyst (the loading amount of nickel is 16 wt% based on Ni), standing at room temperature for 24 hours, drying at 150 °C for 12 hours, and then calcining at 400 °C for 4 hours. Finally, a hierarchically porous nanosheet ZSM-5 catalyst modified with metallic nickel composite can be obtained, and the obtained catalyst is labeled as NZ-1.2M-N.

[0066] Example 4, S1: The molar ratio of tetraethyl orthosilicate, aluminum chloride, tetrapropylammonium hydroxide, ammonium fluoride, and water, which represent the silicon source, aluminum source, template agent, mineralizing agent, and solvent, is 1:0.01:0.14:0.80:80. Take 4.37 g of tetrapropylammonium hydroxide aqueous solution (25 wt%) (containing 1.09 g of tetrapropylammonium hydroxide), add 8 g of tetraethyl orthosilicate and 0.01 g of seed crystals, stir at 40 °C until the tetraethyl orthosilicate is completely hydrolyzed, and label it as solution A. Dissolve 0.19 g of aluminum chloride hexahydrate in 10 g of water, add solution A and continue stirring for 2 hours. Dissolve 1.14 g of ammonium fluoride in 10 g of water, add the above solution, stir for 1 hour, then load it into a crystallization kettle and crystallize at 170 °C for 24 hours.

[0067] S2: Cool and wash the crystallized material in step S1 to neutral, calcine at 540 °C for 6 hours. Finally, a nanosheet ZSM-5 catalyst with a nanosheet layer thickness of 100 nm and a molar ratio of silicon oxide to aluminum oxide of 100 can be obtained, and the obtained catalyst is labeled as NZ.

[0068] S3: Take 5.0 g of the catalyst NZ in step S2 and add it to 25.0 g of sodium hydroxide aqueous solution (1.2 mol / L). The alkali treatment temperature is 80 °C. After stirring or standing the obtained mixed solution (for 0.5 hours), perform solid-liquid separation. After separation, dry and calcine to obtain a hierarchically porous nanosheet ZSM-5 catalyst, where the calcination time is 4 hours and the temperature is 540 °C.

[0069] S4: Shape the catalyst obtained in step S3 using an alumina binder. The mass ratio of the binder in the shaped catalyst is 20%. Exchange the obtained catalyst with ammonium nitrate aqueous solution (1.0 mol / L) 3 times at 80 °C, and then calcine at 540 °C for 4 hours. Finally, a hierarchically porous nanosheet catalyst can be obtained, and the obtained catalyst is labeled as NZ-1.2M.

[0070] S5: Take the catalyst NZ-1.2M in step S4 and impregnate the cyclohexane solution of tetraethyl orthosilicate onto the surface of the catalyst by the incipient wetness impregnation method (the loading amount of silicon calculated as SiO2 is 10 wt%). Let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon-modified hierarchical porous nanosheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-1.2M-S.

[0071] Take the catalyst NZ-1.2M-S and impregnate the aqueous solution of ammonium dihydrogen phosphate onto the surface of the catalyst by the incipient wetness impregnation method (the loading amount of phosphorus calculated as P2O5 is 3 wt%). Let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon- and phosphorus-modified hierarchical porous nanosheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-1.2M-SP.

[0072] S6: Take the catalyst NZ-1.2M-SP in step S5 and impregnate the platinum precursor solution onto the surface of the obtained catalyst (the loading amount of platinum calculated as Pt is 0.03 wt%). Let it stand at room temperature for 24 hours, dry it at 150 °C for 12 hours, and then calcine it at 400 °C for 4 hours. Finally, a hierarchically porous nanosheet ZSM-5 catalyst modified with platinum metal composite can be obtained, and the obtained catalyst is labeled as NZ-1.2M-M.

[0073] Where step S6 can also be: Take the catalyst NZ-1.2M-SP in step S5 and impregnate the nickel precursor solution onto the surface of the obtained catalyst (the loading amount of nickel calculated as Ni is 10 wt%). Let it stand at room temperature for 24 hours, dry it at 150 °C for 12 hours, and then calcine it at 400 °C for 4 hours. Finally, a hierarchically porous nanosheet ZSM-5 catalyst modified with nickel metal composite can be obtained, and the obtained catalyst is labeled as NZ-1.2M-N.

[0074] Where step S6 can also be: Take the catalyst NZ-1.2M-M in step S6 and impregnate the nickel precursor solution onto the surface of the obtained catalyst (the loading amount of nickel calculated as Ni is 10 wt%). Let it stand at room temperature for 24 hours, dry it at 150 °C for 12 hours, and then calcine it at 400 °C for 4 hours. Finally, a hierarchically porous nanosheet ZSM-5 catalyst modified with nickel metal composite can be obtained, and the obtained catalyst is labeled as NZ-1.2M-MN.

[0075] It should be noted that the silicon source can be one or a mixture of more than one of tetraethyl orthosilicate, silica sol, water glass, precipitated silica, sodium silicate, silicic acid, silica gel, and diatomaceous earth; the aluminum source is one or a mixture of more than one of aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum hydroxide, aluminum isopropoxide, and sodium metaaluminate. The template agent is one or a mixture of more than one of n-butylamine, tetrapropylammonium hydroxide, tetrapropylammonium bromide, and ethylene glycol. The mineralizing agent is one or a mixture of more than one of ammonium fluoride, urea, starch, sodium hydroxide, ammonium carbonate, and ammonium bicarbonate. The ion exchange solution can be one or a mixture of more than one of ammonium nitrate, ammonium chloride, ammonium carbonate, ammonium bicarbonate, hydrochloric acid, and nitric acid solution. There is a certain sequence in the silicon, phosphorus, platinum, and nickel modification procedures. For example, silicon modification is carried out first, followed by phosphorus modification, and finally metal modification. However, silicon modification does not necessarily have to be the first step. It can be inserted between the phosphorus, platinum, and nickel modification procedures. And the metal modification procedure includes modification using at least one metal selected from noble metals and non-noble metals, where noble metals include but are not limited to Pt, Pd, Ru, Rh, Au, Ag, etc., and non-noble metals include but are not limited to Ni, Co, Fe, Cu, Mo, W, etc. The ZSM-5 catalyst has at least one shape among nano-sheet shape, nano-spherical shape, nano-aggregate shape, and nano-needle shape. When modification is carried out in step S5, modification can be carried out using one or a mixture of both of a silicon and a phosphorus solution; in step S6, modification can also be carried out using one or a mixture of both of a platinum and a nickel metal precursor solution; and the solution for ion exchange can be an aqueous ammonium nitrate solution. The binder is selected from one or a mixture of both of alumina and silica.

[0076] Comparative Example 1, Synthesis of Micron-Sheet ZSM-5 Catalyst: 4.37 g of tetrapropylammonium hydroxide aqueous solution (25 wt%) was taken and added to 8 g of tetraethyl orthosilicate, and stirred at 40 °C until tetraethyl orthosilicate was completely hydrolyzed, marked as Solution A. 0.19 g of aluminum chloride hexahydrate was dissolved in 8 g of water, added to Solution A and stirred for another 2 hours. Finally, 1.14 g of ammonium fluoride and 8 g of water were added to the above solution, stirred for 1 hour, then loaded into a crystallization kettle and crystallized at 170 °C for 72 hours. After crystallization, it was cooled and washed to neutrality, and calcined at 540 °C for 6 hours. Finally, a micron-sheet ZSM-5 catalyst with a micron-sheet layer thickness of 2 microns and a silica-alumina ratio of 50 was obtained, and the obtained catalyst was marked as MZ. Synthesis of Silicon-Modified Micron-Sheet ZSM-5 Catalyst: The catalyst MZ was taken, and the cyclohexane solution of tetraethyl orthosilicate was impregnated onto the catalyst surface by the equal-volume impregnation method, left standing at room temperature for 4 hours, dried at 80 °C for 4 hours, and then calcined at 540 °C for 4 hours. Finally, a silicon-modified micron-sheet ZSM-5 catalyst was obtained, and the obtained catalyst was marked as MZ-S. Synthesis of Silicon- and Phosphorus-Modified Micron-Sheet ZSM-5 Catalyst: The catalyst MZ-S was taken, and the aqueous solution of ammonium dihydrogen phosphate was impregnated onto the catalyst surface by the equal-volume impregnation method, left standing at room temperature for 4 hours, dried at 80 °C for 4 hours, and then calcined at 540 °C for 4 hours. Finally, a silicon- and phosphorus-modified micron-sheet ZSM-5 catalyst was obtained, and the obtained catalyst was marked as MZ-SP. Synthesis of Metal Platinum Composite-Modified Micron-Sheet ZSM-5 Catalyst: The catalyst MZ-SP was taken, and the platinum precursor solution was impregnated onto the obtained catalyst surface, left standing at room temperature for 24 hours, dried at 150 °C for 12 hours, and then calcined at 400 °C for 4 hours. Finally, a metal platinum composite-modified micron-sheet ZSM-5 catalyst was obtained, and the obtained catalyst was marked as MZ-M. Metal Nickel Composite-Modified Micron-Sheet ZSM-5 Catalyst: The catalyst MZ-SP was taken, and the nickel precursor solution was impregnated onto the obtained catalyst surface, left standing at room temperature for 24 hours, dried at 150 °C for 12 hours, and then calcined at 400 °C for 4 hours. Finally, a composite-modified micron-sheet ZSM-5 catalyst was obtained, and the obtained catalyst was marked as MZ-N.

[0077] Comparative Example 2, Synthesis of Silicon-Modified Nano-Sheet ZSM-5 Catalyst: Take catalyst NZ, and by the method of equal-volume impregnation, impregnate the cyclohexane solution of tetraethyl orthosilicate onto the catalyst surface, let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon-modified nano-sheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-S. Synthesis of Silicon- and Phosphorus-Modified Nano-Sheet ZSM-5 Catalyst: Take catalyst NZ-S, and by the method of equal-volume impregnation, impregnate the aqueous solution of ammonium dihydrogen phosphate onto the catalyst surface, let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon- and phosphorus-modified nano-sheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-SP.

[0078] Comparative Example 3, Synthesis of Hierarchical Nano-Sheet ZSM-5 Catalyst: Take 5.0 g of the catalyst NZ in Example 4 and add it to 25.0 g of an aqueous sodium hydroxide solution (0.6 mol / L). Stir the obtained mixed solution vigorously in a water bath at 80 °C for 0.5 hour. Separate the catalyst by centrifugation multiple times and wash it until neutral, then calcine it at 540 °C for 4 hours. Exchange the obtained catalyst with ammonium nitrate solution (1.0 mol / L) at 80 °C for 3 times, and then calcine it at 540 °C for 4 hours. Finally, a hierarchical nano-sheet catalyst can be obtained, and the obtained catalyst is labeled as NZ-0.6M. Synthesis of Silicon-Modified Hierarchical Nano-Sheet ZSM-5 Catalyst: Take catalyst NZ-0.6M, and by the method of equal-volume impregnation, impregnate the cyclohexane solution of tetraethyl orthosilicate onto the catalyst surface, let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon-modified hierarchical nano-sheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-0.6M-S. Synthesis of Silicon- and Phosphorus-Modified Hierarchical Nano-Sheet ZSM-5 Catalyst: Take catalyst NZ-0.6M-S, and by the method of equal-volume impregnation, impregnate the aqueous solution of ammonium dihydrogen phosphate onto the catalyst surface, let it stand at room temperature for 4 hours, dry it at 80 °C for 4 hours, and then calcine it at 540 °C for 4 hours. Finally, a silicon- and phosphorus-modified hierarchical nano-sheet ZSM-5 catalyst can be obtained, and the obtained catalyst is labeled as NZ-0.6M-SP.

[0079] In addition, another embodiment of the present invention also provides an application of a composite-modified hierarchical nano-sheet ZSM-5 catalyst in the toluene methanol alkylation reaction, including:

[0080] Example 1: 0.6 g of the catalyst was loaded into a self-built fixed-bed reactor. The catalyst was filled in the isothermal section of the reactor, and inert porcelain balls were filled in the upper and lower parts of the isothermal section. The reactor was heated to 460 °C at a rate of 5 °C per minute in a hydrogen atmosphere. The reaction pressure was 0.1 MPa, and the hydrogen / hydrocarbon molar ratio was 2. After the reactor temperature was stabilized, the mixed feed was started. A mixed solution of toluene and methanol (molar ratio of 2) was fed into the vaporizer at a feed rate of 6 h -1 -1. The product of the reactor was separated into gas-phase and liquid-phase products by a cold trap.

[0081] Example 2: 0.6 g of the catalyst was loaded into a self-built fixed-bed reactor. The catalyst was filled in the isothermal section of the reactor, and inert porcelain balls were filled in the upper and lower parts of the isothermal section. The reactor was heated to 300 °C at a rate of 5 °C per minute in a hydrogen atmosphere. The reaction pressure was 1.5 MPa, and the hydrogen / hydrocarbon molar ratio was 0.2. After the reactor temperature was stabilized, the mixed feed was started. A mixed solution of toluene and methanol (molar ratio of 1) was fed into the vaporizer at a feed rate of 0.5 h -1 -1. At the same time, water was fed into the vaporizer at a feed rate of water / hydrocarbon molar ratio of 0.2. After being mixed evenly in the vaporizer, it entered the reactor. The product of the reactor was separated into gas-phase and liquid-phase products by a cold trap.

[0082] Example 3: 0.6 g of the catalyst was loaded into a self-built fixed-bed reactor. The catalyst was filled in the isothermal section of the reactor, and inert porcelain balls were filled in the upper and lower parts of the isothermal section. The reactor was heated to 600 °C at a rate of 5 °C per minute in a hydrogen atmosphere. The reaction pressure was 3.0 MPa, and the hydrogen / hydrocarbon molar ratio was 10. After the reactor temperature was stabilized, the mixed feed was started. A mixed solution of toluene and methanol (molar ratio of 10) was fed into the vaporizer at a feed rate of 10 h -1 -1. At the same time, water was fed into the vaporizer at a feed rate of water / hydrocarbon molar ratio of 10. After being mixed evenly in the vaporizer, it entered the reactor. The product of the reactor was separated into gas-phase and liquid-phase products by a cold trap.

[0083] It should be noted that the gas-phase product was analyzed by a Fuli GC9720 chromatograph equipped with an HP-PLOT / Q (30 m×0.53 mm×40 μm) capillary column, and the liquid-phase product was analyzed by an Agilent GC6890 chromatograph equipped with an INNOWAX (60 m×0.32 mm×0.5 μm) capillary column.

[0084] The toluene conversion, p-xylene selectivity, and p-xylene yield were defined by the following formulas:

[0085] i. Toluene conversion (%) :

[0086] ii. p - Xylene selectivity (%):

[0087] iii. p - Xylene yield (%):

[0088] Where: n toluene,inlet is the number of moles of toluene in the reactants; n toluene,outlet is the number of moles of toluene in the products; n para-xylene and n meta-xylene and n ortho-xylene are the number of moles of p - xylene, m - xylene, and o - xylene in the products, respectively. Special note: The p - xylene selectivity mentioned in this application is the selectivity of p - xylene in the products among the three xylene isomers.

[0089] Table 1

[0090]

[0091] Table 1 shows the changes in p - xylene selectivity of different samples based on the above Example 1. According to the content of Table 1 above, it can be seen that the selectivity of the hierarchical pore ZSM - 5 catalyst (NZ - 1.2M) provided by the present invention is superior to that of the ZSM - 5 catalyst (NZ) without alkali treatment. At the same time, with the increase in the alkali treatment concentration, the p - xylene selectivity is significantly improved, and the p - xylene yield is increased from 7.7% to 17.1%. This shows that the provided alkali treatment method can significantly improve the shape selectivity and yield of the catalyst.

[0092] Table 2

[0093]

[0094]

[0095] Table 2 shows the influence of different samples on the p - xylene yield based on the above Example 1. It can be seen from the content of Table 2 above that the selectivity of the composite - modified hierarchical pore nanosheet ZSM - 5 catalyst (NZ - 1.2M - SP) provided by this method is superior to that of the composite - modified nanosheet ZSM - 5 catalyst (NZ - SP) without alkali treatment. This shows that the provided alkali treatment method also plays a promoting role in further improving the p - xylene selectivity in the subsequent modification process. At the same time, the p - xylene yield of the composite - modified hierarchical pore nanosheet catalyst (NZ - 1.2M - M) is higher than that of the composite - modified micron - sheet catalyst (MZ - M). More importantly, the stability of NZ - 1.2M - M is 5 times that of MZ - M.

[0096] The improvement in catalyst stability is attributed to the better diffusion performance of the hierarchical pore nano-catalyst, which is beneficial to the faster diffusion of coke species. The above research results show that the alkali treatment method for the nano-sized ZSM-5 catalyst provided in the present invention not only enhances the shape selectivity of the catalyst, but also facilitates further improvement of p-xylene selectivity by subsequent modification. At the same time, the hierarchical pores generated during the alkali treatment process also significantly improve the stability of the catalyst.

[0097] In addition, as Figures 1 to 14 shown, another embodiment of the present invention further provides a device for preparing a composite modified hierarchical pore nano-sheet ZSM-5 catalyst, which can realize operations such as reaction, solid-liquid filtration, and waste liquid treatment during the preparation process of the catalyst by alkali treatment. The device includes a frame body 2, a tank body 1, and an auxiliary mechanism 4. Among them, the tank body 1 is fixedly connected to the frame body 2, and the auxiliary mechanism 4 is arranged inside the tank body 1 to assist in completing the preparation process. A cover body 12 is installed on the side surface of the tank body 1, and the cover body 12 facilitates the user to place raw materials on the filtration component 401 for reaction or take out the raw materials after the reaction. An opening is provided at the top of the tank body 1.

[0098] The auxiliary mechanism 4 includes a filtration component 401, a plug 402, a branch pipe 403, a waste liquid pipe 404, a heating wire 407, a pump body 405, and a backing plate 406. Specifically, the filtration component 401 is slidably connected to the inner wall of the tank body 1, and the filtration component 401 can slide up and down along the inner wall of the tank body 1. The top layer of the filtration component 401 is a PTFE membrane with a pore size of 20-200 nanometers, which is resistant to strong alkalis and intercepts crystal grains; the middle layer is a zirconia ceramic with a pore size of 1-5 micrometers; the bottom layer is 316L stainless steel (pore size 10-50 micrometers), which is corrosion-resistant and strong, ensuring long-term stability; the filtration component 401 takes into account both filtration efficiency and mechanical strength, and the solution passes through while the crystal grains are intercepted. The bottom of the filtration component 401 is fixedly connected to a plug 402, and the outer wall of the plug 402 is adapted to the inner wall of the branch pipe 403 in a clearance fit manner, so that the plug 402 can form a controllable sealed or open state with the branch pipe 403. One end of the branch pipe 403 is communicated with the waste liquid pipe 404, and the waste liquid pipe 404 extends through the side wall or bottom of the tank body 1 to the outside for discharging the waste liquid generated during the preparation process. The other end of the branch pipe 403 passes through the backing plate 406, and the backing plate 406 is fixedly connected to the inner wall of the tank body 1 as a support structure for the auxiliary mechanism 4. The heating wire 407 is arranged in the space between the backing plate 406 and the filtration component 401 for heating and calcining the materials inside the tank body 1 to meet the temperature requirements during the preparation process. The heating wire is connected to an external power supply through an insulated sealed joint; the top of the tank is equipped with a detachable PTFE cover plate; the overall structure is compact, ensuring that the heating wire is not exposed to air when soaked and maintaining the chemical stability of the solution.

[0099] The bottom of the backing plate 406 is connected to the output end of the pump body 405. The sodium hydroxide solution is stored below the interior of the tank body 1. The pump body 405 can pump the sodium hydroxide solution into the space above the backing plate 406 for alkali treatment.

[0100] During actual use, first, place the raw materials required for preparing the composite modified hierarchical pore nano-sheet ZSM-5 catalyst in the tank body 1. Start the pump body 405. Through the suction effect of the output of the pump body 405, the sodium hydroxide solution can be pumped into the space above the backing plate 406 to perform alkali treatment on the raw materials on the filter assembly 401. After the reaction, the filter assembly 401 can drive the plug 402 to disengage from the branch pipe 403 by moving upward. The waste liquid after alkali treatment flows out of the tank body 1 through the branch pipe 403 and finally through the waste liquid pipe 404. At the same time, during the process of the filter assembly 401 being lifted upward, the alkali solution and the raw materials will be separated. The above equipment realizes the integrated operation of reaction, filtration and waste liquid treatment by setting the auxiliary mechanism 4, which not only improves the preparation efficiency, but also simplifies the process flow.

[0101] In this embodiment, it further includes a main shaft 10, a motor 3, and a stirring assembly 5, a leveling assembly 6 and a linkage mechanism 9 arranged inside the tank body 1. Among them, the tank body 1 is fixedly connected to the frame body 2. The main shaft 10 is rotatably connected to the tank body 1 through a bearing. The input end of the main shaft 10 is connected to the output end of the motor 3. The motor 3 is used to provide rotational driving force for the main shaft 10. The stirring assembly 5, the leveling assembly 6 and the linkage mechanism 9 are arranged inside the tank body 1. The linkage mechanism 9 can drive the stirring assembly 5 to move upward and at the same time drive the leveling assembly 6 to move downward to realize the coordinated operation of stirring and leveling.

[0102] The stirring assembly 5 includes a stirring rod 507, a circular sleeve 506, a limiting plate 505, a first annular plate 503, a second annular plate 504, a limiting strip 508, a connecting plate 502 and a connecting rod 501, and is used for mixing and stirring the raw materials in the tank body 1. Specifically, the filter assembly 401 is fixedly connected to the connecting plate 502 through the connecting rod 501. The connecting plate 502 is slidably connected to the inner wall of the tank body 1, so that the connecting plate 502 can move up and down along the inner wall of the tank body 1. The connecting plate 502 is fixedly connected to the first annular plate 503. The first annular plate 503 is fixedly connected to the second annular plate 504. The mutually approaching sides of the first annular plate 503 and the second annular plate 504 are respectively attached to the upper and lower sides of the limiting plate 505. The limiting plate 505 is connected to the stirring rod 507 through the circular sleeve 506. The circular sleeve 506 is sleeved on the limiting strip 508 and is slidably connected to the limiting strip 508, so that the stirring rod 507 can only rotate along with the main shaft 10. The limiting strip 508 is fixedly connected to the main shaft 10. Through the rotation of the main shaft 10, the limiting strip 508 drives the circular sleeve 506 and the stirring rod 507 to rotate, thereby realizing the stirring function.

[0103] In actual use, the user can start the motor 3 to drive the main shaft 10 to rotate. The main shaft 10 drives the circular sleeve 506 and the stirring rod 507 to rotate in the tank body 1 through the limiting strip 508, so as to fully mix the raw materials. During the stirring process, the linkage mechanism 9 can drive the stirring assembly 5 to move upward as needed, and at the same time drive the flattening assembly 6 to move downward to flatten the stirred materials and ensure uniform distribution of the materials. After flattening, the materials can be further processed through subsequent processes (such as filtration or heating).

[0104] In this embodiment, the flattening assembly 6 is also arranged inside the main shaft 10. As one of the key components, the flattening assembly 6 is arranged inside the main shaft 10 and is used to flatten the materials during the preparation process to improve the uniformity of material distribution, so as to facilitate the normal progress of the drying and roasting processes. The flattening assembly 6 is installed inside the main shaft 10 and rotates together with the main shaft 10.

[0105] The flattening assembly 6 includes a back plate 601, side plates 602, a shaft body 603, a torsion spring 604, a rotating plate 605, a rounded corner 606 and a scraping bar 607. Specifically, the back plate 601 is slidably connected to the inner wall of the main shaft 10, and the back plate 601 can slide axially or radially along the inner wall of the main shaft 10 to adjust the working position of the flattening assembly 6. The back plate 601 is fixedly connected to the side plates 602, and the side plates 602 are rotatably connected to the rotating plate 605 through the shaft body 603, so that the rotating plate 605 can rotate around the shaft body 603. The torsion spring 604 is sleeved on the shaft body 603, and both ends of the torsion spring 604 are fixedly connected to one side of the shaft body 603 and one side of the side plate 602 respectively. The torsion spring 604 is used to provide an elastic restoring force for the rotating plate 605. The scraping bar 607 is fixedly connected to the rotating plate 605, and the scraping bar 607 is used to directly contact the materials and perform the flattening operation. A rounded corner 606 is machined on one side of the rotating plate 605 close to the scraping bar 607. Among them, the rotating plate 605 is inclined in the counterclockwise rotation direction, and the included angle between the rotating plate 605 and the vertical direction is 15 degrees, which can ensure that the rounded corner 606 will contact the filtering assembly 401 first.

[0106] In actual use, the linkage mechanism 9 drives the back plate 601 to slide along the inner wall of the main shaft 10 to a predetermined position. During the downward movement of the back plate 601, the rounded corner 606 will contact the filtering assembly 401 first. The rounded corner 606 reduces the friction between the rotating plate 605 and the filtering assembly 401 until the rotating plate 605 is in a horizontal state. At this time, the torsion spring 604 is in a deformed state, and at this time, the scraping bar 607 will flatten the raw materials on the filtering assembly 401 under the drive of the main shaft 10. Through the flattening effect of the scraping bar 607 of the above-mentioned flattening assembly 6, the materials are evenly distributed on the filtering assembly 401, providing a good material state for the preparation of the composite modified hierarchical pore nano-sheet ZSM-5 catalyst.

[0107] In this embodiment, it further includes a power output mechanism 8 and a chute 11. The chute 11 is machined on the main shaft 10. The linkage mechanism 9 includes a connecting shaft 901, a gear 902, a first rack 903, a contact plate 906, a slider 907, a guide plate 908, a rod 909, a partition plate 911, a spring 910, a first guide bar 905, a second guide bar 912, a second rack 913, and a transmission rod 904. Among them, in the linkage mechanism 9, except for the guide plate 908, the rod 909, the partition plate 911, and the spring 910. The output end of the power output mechanism 8 is fixedly connected to the connecting shaft 901, and the power output mechanism 8 can drive the two gears 902 to move synchronously in opposite movement modes. The connecting shaft 901 is fixedly connected to the gear 902, and the gear 902 is respectively meshed and connected to the first rack 903 and the second rack 913, so that the rotation of the gear 902 can drive the first rack 903 and the second rack 913 to move in opposite directions at the same time. The first rack 903 is slidably connected to the first guide bar 905, and the second rack 913 is slidably connected to the second guide bar 912. Both the first guide bar 905 and the second guide bar 912 are fixedly connected to the inner wall of the tank body 1 to define the movement paths of the first rack 903 and the second rack 913. The second rack 913 is fixedly connected to the second annular plate 504 through the transmission rod 904 for driving the stirring rod 507 to move. The first rack 903 is fixedly connected to the contact plate 906, and the contact plate 906 can contact the slider 907 and drive the slider 907 to move. The slider 907 is slidably connected to the inner side of the second rack 913, and the slider 907 is fixedly connected to the guide plate 908. The guide plate 908 is simultaneously slidably connected to the chute 11 and the inner wall of the main shaft 10. The bottom of the guide plate 908 is fixedly connected to the top of the back plate 601, thereby driving the movement of the leveling assembly 6. The top of the guide plate 908 is fixedly connected to the rod 909. The rod 909 passes through the partition plate 911 and is slidably connected to the partition plate 911. The partition plate 911 is fixedly connected to the inner wall of the main shaft 10. The spring 910 is sleeved on the rod 909, and both ends of the spring 910 are fixedly connected to the upper part of the rod 909 and the top of the partition plate 911 respectively, for providing an elastic restoring force for the guide plate 908.

[0108] In actual use, first, the power output mechanism 8 is started, and the gear 902 is driven to rotate through the connecting shaft 901. The rotation of the gear 902 drives the first rack 903 and the second rack 913 to move in opposite directions along the first guide bar 905 and the second guide bar 912 respectively. The second rack 913 pushes the second annular plate 504 upward through the transmission rod 904, thereby driving structures such as the stirring rod 507 to rise; at the same time, the first rack 903 drives the contact plate 906 to move, and the second rack 913 drives the guide plate 908 to slide downward along the chute 11 through the slider 907, and the guide plate 908 further drives the back plate 601 and the entire flattening assembly 6 to move downward. The spring 910 is compressed or stretched under the drive of the rod body 909, providing a restoring force for the guide plate 908, which can ensure that the slider 907 is always in a predetermined position, ensuring the smoothness and controllability of the movement. Through the above linkage design, the stirring assembly 5 rises while the flattening assembly 6 descends, realizing the coordinated operation of the lifting and flattening actions of the filtering assembly 401. After completion, the power output mechanism 8 can run in reverse to reset each component to the initial position. Through the cooperation of the power output mechanism 8 and the linkage mechanism 9, the device realizes the automatic linkage of solid-liquid separation and flattening.

[0109] In this embodiment, a drying mechanism 7 is provided on the outer side of the tank body 1. The drying mechanism 7 includes a first baffle 701, a first plug board 702, an air inlet hole 703, two air outlet holes 706, a second baffle 704, a second plug board 705, a connecting plate 709, an electric push rod 710, a blower 708, and an air inlet pipe 707. Specifically, both the first baffle 701 and the second baffle 704 are fixedly connected to the outer wall of the tank body 1. The first baffle 701 and the second baffle 704 are located on different sides of the tank body 1 respectively to form an air flow inlet and outlet channel. The first plug board 702 is slidably connected to the first baffle 701, and the second plug board 705 is slidably connected to the second baffle 704. Both the first plug board 702 and the second plug board 705 are fixedly connected to the connecting plate 709. The connecting plate 709 is fixedly connected to the outer wall of the tank body 1 through the electric push rod 710. The telescopic end of the electric push rod 710 is connected to the connecting plate 709 and is used to drive the first plug board 702 and the second plug board 705 to slide synchronously to control the on-off of the air flow. The air inlet hole 703 is machined on the wall surface of the tank body 1. The positions of the air inlet hole 703 and the air outlet holes 706 correspond to the position of the heating wire 407. And it corresponds to the position of the first plug board 702. When the first plug board 702 slides to a specific position, the air inlet hole 703 can be opened or closed. The two air outlet holes 706 are respectively machined on the second baffle 704 and the wall surface of the tank body 1, and the positions of the two air outlet holes 706 correspond to each other and correspond to the second plug board 705. The sliding of the second plug board 705 can control the opening and closing of the air outlet holes 706. The input end of the blower 708 is communicated with the air outlet hole 706 machined on the second baffle 704, and the output end of the blower 708 is communicated with the air inlet pipe 707. The air inlet pipe 707 passes through the wall surface of the tank body 1 and extends into the tank body 1 and is used to transport the air flow into the tank body 1. The air inlet position of the air inlet pipe 707 corresponds to the highest position after the movement of the filter assembly 401. During the drying process, the high-temperature air discharged from the air inlet pipe 707 will be input to the raw materials on the filter assembly 401 for drying.

[0110] In actual use, first, during the preparation of the catalyst, when it is necessary to dry the materials in the tank body 1, after the filtering assembly 401 reaches the highest position, the waste liquid has been discharged through the branch pipe 403 and the waste liquid pipe 404. At this time, the electric push rod 710 is started. The electric push rod 710 extends or contracts to drive the connection plate 709 to move, so that the first plug board 702 and the second plug board 705 slide along the first baffle 701 and the second baffle 704 to the open position respectively, where the first plug board 702 and the second plug board 705 do not completely separate from the first baffle 701 and the second baffle 704. At this time, the air inlet hole 703 and the two air outlet holes 706 are all in a communicating state. Subsequently, the fan 708 and the heating wire 407 are started. The heating wire 407 heats the air near the air inlet hole 703 in the tank body 1. The fan 708 extracts the air in the tank body 1 through the air outlet hole 706 on the second baffle 704 and inputs the air into the filtering assembly 401 in the tank body 1 through the air inlet pipe 707, realizing the drying of the raw materials on the filtering assembly 401. After the drying is completed, the electric push rod 710 acts in the reverse direction, driving the first plug board 702 and the second plug board 705 to slide to the closed position, closing the air inlet hole 703 and the air outlet hole 706, and stopping the air flow circulation. At this time, the filtering assembly 401 is reset under the drive of the linkage mechanism 9, and thus the heating wire 407 is started for the calcination work. The drying mechanism 7 controls the opening and closing of the plug board through the electric push rod 710 and drives the air flow circulation by the fan 708, realizing the drying of the materials in the tank body 1, providing a drying guarantee for the preparation of the composite modified hierarchical pore nano-sheet ZSM-5 catalyst.

Claims

1. A preparation method of a composite modified hierarchical porous nanosheet ZSM-5 catalyst, characterized in that, It includes the following steps: S1, hydrolyze a silicon source, an aluminum source, a template agent, a mineralizing agent and a solvent, and perform crystallization in a crystallization kettle after hydrolysis; S2, dry the crystals in the crystallization kettle obtained in step S1 to obtain a nano-sheet-like ZSM-5 catalyst; S3, mix the nano-sheet-like ZSM-5 catalyst obtained in step S2 with an alkali solution and then separate it from the alkali solution, wash it to neutrality and perform a drying treatment to obtain a hierarchical pore nano-sheet-like ZSM-5 catalyst; S4, perform a shaping treatment on the hierarchical pore nano-sheet-like ZSM-5 catalyst obtained in step S3, and perform ion exchange on the hierarchical pore nano-sheet-like ZSM-5 catalyst after the shaping treatment is completed; S5, impregnate the ion-exchanged hierarchical pore nano-sheet-like ZSM-5 catalyst obtained in step S4 with a cyclohexane solution of tetraethyl orthosilicate to obtain a silicon-modified hierarchical pore nano-sheet-like ZSM-5 catalyst; impregnate the obtained silicon-modified hierarchical pore nano-sheet-like ZSM-5 catalyst with an aqueous solution of ammonium dihydrogen phosphate to obtain a silicon and phosphorus-modified hierarchical pore nano-sheet-like ZSM-5 catalyst; S6, perform metal modification on the silicon and phosphorus-modified hierarchical pore nano-sheet-like ZSM-5 catalyst obtained in step S5, and then obtain a composite-modified hierarchical pore nano-sheet-like ZSM-5 catalyst after a drying treatment.

2. The preparation method of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to claim 1, characterized in that, The silicon source is tetraethyl orthosilicate; the aluminum source is aluminum chloride; the template agent is tetrapropylammonium hydroxide; the mineralizing agent is ammonium fluoride; The solution for ion exchange in step S4 is an aqueous ammonium nitrate solution; In step S5, one or a mixture of both selected from silicon and phosphorus solutions is used for modification; In step S6, one or a mixture of both selected from platinum and nickel metal precursor solutions is used for metal modification.

3. The preparation method of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to claim 1, characterized in that, The molar ratio of silicon oxide to aluminum oxide in the nano-sheet-like ZSM-5 catalyst is 20 - 400, and the grain size of the nano-sheet-like ZSM-5 catalyst is 30 - 300 nanometers; The crystallization temperature for preparing the nano-sheet-like ZSM-5 catalyst is 150 - 190 degrees Celsius, the crystallization time is 12 - 96 hours, and the molar ratio of the silicon source, aluminum source, template agent, mineralizing agent, and solvent is 1:(0.0025 - 0.05):(0.05 - 0.80):(0.10 - 0.80):(10 - 100); The nano-sheet-like ZSM-5 catalyst and the alkali solution are mixed by stirring or standing. The alkali solution is a sodium hydroxide solution. The alkali treatment temperature is 20 - 95 degrees Celsius, the concentration of the sodium hydroxide solution is 0.1 - 2.0 moles per liter, and the mixing time is 0.1 - 20 hours; In step S4, a binder is used for the shaping treatment, wherein the binder is selected from one or a mixture of both of alumina and silica, and the mass ratio of the binder in the shaped catalyst is 5% - 80%.

4. The preparation method of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to claim 1, characterized in that, During the modification process according to Steps S5 and S6, the loading amount of silicon is 0.5 - 30 wt% calculated as SiO₂, the loading amount of phosphorus is 0.1 - 20 wt% calculated as P₂O₅, the loading amount of platinum is 0.01 - 2 wt% calculated as Pt, and the loading amount of nickel is 0.1 - 30 wt% calculated as Ni.

5. The preparation method of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to claim 1, characterized in that, In the process of preparing the composite-modified hierarchical porous nanosheet ZSM-5 catalyst, for the hierarchical porous nanosheet ZSM-5 catalyst: perform the first modification, selected from silicon modification, phosphorus modification, and metal modification; perform the second modification, selected from silicon modification, phosphorus modification, and metal modification, where the second modification is different from the first modification; perform the third modification, selected from silicon modification, phosphorus modification, and metal modification, where the third modification is different from both the first modification and the second modification; wherein the metal modification includes treating the catalyst with at least one metal selected from at least one of Pt, Pd, Ru, Rh, Au, Ag, Ni, Co, Fe, Cu, Mo, and W.

6. The preparation method of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to claim 1, characterized in that, wherein the first modification is silicon modification, the second modification is phosphorus modification, and the third modification is metal modification; wherein the metal modification includes at least one noble metal selected from Pt, Pd, Ru, Rh, Au, and Ag, and at least one non-noble metal selected from Ni, Co, Fe, Cu, Mo, and W.

7. Use of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to any one of claims 1 to 6 in the alkylation reaction of toluene with methanol, characterized in that, comprises the following steps: A1, load the composite-modified hierarchical porous nanosheet ZSM-5 catalyst obtained in Step S6 into the isothermal section of a fixed-bed reactor; A2, fill inert porcelain balls at both the upper and lower parts of the isothermal section of the fixed-bed reactor; A3, gradually heat the fixed-bed reactor to 300 - 600 °C in a hydrogen environment, with a hydrogen / hydrocarbon molar ratio of 0.2 - 10 and a reaction pressure of 0.1 - 3.0 MPa; A4, A mixed solution of toluene and methanol with a molar ratio of 1 - 10 is fed into a vaporizer at a feed rate of 0.5 - 10 h⁻¹ in terms of mass space velocity; -1 ; A5, feed at a water / hydrocarbon molar ratio of 0.2 - 10 into a vaporizer, mix evenly in the vaporizer and then enter the reactor; A6, separate the reactor product into a gas-phase product and a liquid-phase product through a cold trap, and perform chromatographic analysis on the gas-phase product and the liquid-phase product respectively.

8. An apparatus for preparing a composite modified hierarchical porous nanosheet ZSM-5 catalyst according to any one of claims 1 to 6, characterized in that, comprises a frame body (2), a tank body (1), and an auxiliary mechanism (4), the tank body (1) is connected to the frame body (2), and the auxiliary mechanism (4) is arranged inside the tank body (1); the auxiliary mechanism (4) includes a filtration component (401), a plug (402), a branch pipe (403), a waste liquid pipe (404), a heating wire (407), a pump body (405), and a backing plate (406); The filtering component (401) is slidably connected to the inner wall of the tank body (1). The bottom of the filtering component (401) is connected to the plug (402). The outer wall of the plug (402) is in clearance fit with the inner wall of the branch pipe (403). The branch pipe (403) is communicated with the waste liquid pipe (404). The waste liquid pipe (404) passes through the tank body (1). The branch pipe (403) passes through the backing plate (406). The backing plate (406) is connected to the inner wall of the tank body (1). The heating wire (407) is arranged between the backing plate (406) and the filtering component (401). The bottom of the backing plate (406) is connected to the output end of the pump body (405).

9. The preparation equipment of the composite modified hierarchical porous nanosheet ZSM-5 catalyst according to claim 8, characterized in that, It further includes a main shaft (10), a motor (3), and a stirring component (5), a flattening component (6), and a linkage mechanism (9) arranged inside the tank body (1). When the linkage mechanism (9) drives the stirring component (5) to move upward, it will also drive the flattening component (6) to move downward. The main shaft (10) is rotatably connected to the tank body (1). The main shaft (10) is connected to the output end of the motor (3); The stirring component (5) includes a stirring rod (507), a circular sleeve (506), a limiting plate (505), a first annular plate (503), a second annular plate (504), a limiting strip (508), a connecting plate (502), and a connecting rod (501); The filtering component (401) is connected to the connecting plate (502) through the connecting rod (501). The connecting plate (502) is slidably connected to the inner wall of the tank body (1). The connecting plate (502) is connected to the first annular plate (503). The first annular plate (503) is connected to the second annular plate (504). The limiting plate (505) is attached to the side of the first annular plate (503) and the second annular plate (504) that are close to each other. The limiting plate (505) is connected to the circular sleeve (506). The circular sleeve (506) is connected to the stirring rod (507). The limiting strip (508) is connected to the main shaft (10). The limiting strip (508) is slidably connected to the circular sleeve (506); The flattening component (6) is also arranged inside the main shaft (10). The flattening component (6) includes a back plate (601), side plates (602), a shaft body (603), a torsion spring (604), a rotating plate (605), a fillet (606), and a scraping strip (607); The back plate (601) is slidably connected to the inner wall of the main shaft (10). The back plate (601) is connected to the side plate (602). The side plate (602) is rotatably connected to the shaft body (603). The shaft body (603) is connected to the rotating plate (605). The torsion spring (604) is sleeved on the shaft body (603). Two ends of the torsion spring (604) are respectively connected to one side of the shaft body (603) and one side of the side plate (602). The scraping strip (607) is connected to the rotating plate (605). The rounded corner (606) is machined below the rotating plate (605) and on one side close to the scraping strip (607).

10. The preparation equipment of the composite modified hierarchical pore nanosheet ZSM-5 catalyst according to claim 9, characterized in that, It further includes a power output mechanism (8) and a sliding groove (11). The sliding groove (11) is machined on the main shaft (10). The linkage mechanism (9) includes a connecting shaft (901), a gear (902), a first rack (903), a contact plate (906), a slider (907), a guide plate (908), a rod body (909), a partition plate (911), a spring (910), a first guide strip (905), a second guide strip (912), a second rack (913) and a transmission rod (904); The output end of the power output mechanism (8) is connected to the connecting shaft (901). The connecting shaft (901) is connected to the gear (902). The gear (902) is respectively meshed and connected to the first rack (903) and the second rack (913). The first rack (903) and the second rack (913) are respectively slidably connected to the first guide strip (905) and the second guide strip (912). The first guide strip (905) and the second guide strip (912) are connected to the inner wall of the tank body (1). The second rack (913) is connected to the second annular plate (504) through the transmission rod (904). The first rack (903) is connected to the contact plate (906). The slider (907) is slidably connected to the inner side of the second rack (913). The slider (907) is connected to the guide plate (908). The guide plate (908) is respectively slidably connected to the sliding groove (11) and the inner wall of the main shaft (10). The bottom of the guide plate (908) is connected to the top of the back plate (601). The top of the guide plate (908) is connected to the rod body (909). The rod body (909) is connected to the partition plate (911). The partition plate (911) is connected to the inner wall of the main shaft (10). The spring (910) is sleeved on the rod body (909). Two ends of the spring (910) are respectively connected to the upper part of the rod body (909) and the top of the partition plate (911); A drying mechanism (7) is provided on the outer side of the tank body (1). The drying mechanism (7) includes a first baffle (701), a first plug board (702), an air inlet hole (703), two air outlet holes (706), a second baffle (704), a second plug board (705), a connecting plate (709), an electric push rod (710), a blower (708) and an air inlet pipe (707); The first baffle (701) and the second baffle (704) are both connected to the outer wall of the tank body (1). The first plug board (702) and the second plug board (705) are respectively slidably connected to the first baffle (701) and the second baffle (704). The first plug board (702) and the second plug board (705) are both connected to the connecting plate (709). The connecting plate (709) is connected to the electric push rod (710). The electric push rod (710) is connected to the tank body (1). The air inlet hole (703) is machined on the tank body (1). The air inlet hole (703) corresponds to the first plug board (702). The two air outlet holes (706) are respectively machined on the second baffle (704) and the tank body (1). The two air outlet holes (706) correspond to each other and correspond to the second plug board (705). The input end of the blower (708) is communicated with the air outlet hole (706) machined on the second baffle (704). The output end of the blower (708) is connected to the air inlet pipe (707). The air inlet pipe (707) passes through the tank body (1).

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