Molecular sieve synthesis device and method for preparing hierarchical pore nano ZSM-5 molecular sieve by using same

Abstract

The present invention relates to a molecular sieve synthesis apparatus and a method for preparing a hierarchical pore nano ZSM-5 molecular sieve by using the same, the molecular sieve synthesis apparatus comprises a pre-gel and crystallization reaction synergy apparatus, the pre-gel and crystallization reaction synergy apparatus comprises at least two feed ports, the first feed port is connected with a first raw material blending unit through a first flow control unit, and the second feed port is connected with a second raw material blending unit through a second flow control unit; the second feeding hole is connected with the second raw material blending unit through the second flow control unit; at least one ultrasonic generator arranged on the inner side wall and at least one microwave generator arranged in the interlayer of the side wall are arranged in the pre-gel and crystallization reaction synergistic device. The molecular sieve synthesis device comprises a pre-gel and crystallization reaction synergistic device, can realize highly uniform mixing of pre-gel reaction between raw materials, can also realize rapid crystallization and induction of a hierarchical pore structure, further realizes directional regulation and control of the particle size and the pore structure of the molecular sieve, and improves the synthesis efficiency of the molecular sieve. The particle size and production efficiency of the molecular sieve are effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of nanoporous material preparation, and in particular to a molecular sieve synthesis device and a method for preparing a multi-level porous nano ZSM-5 molecular sieve using the same. Background Art

[0002] Hierarchical nano ZSM-5 molecular sieve is a nano functional catalytic material. It has unique advantages such as good selectivity, thermal stability, hydrothermal stability, hydrophobicity and acid resistance. It is widely used in petrochemical, fine chemical, coal chemical and environmental protection fields.

[0003] At present, the ZSM-5 molecular sieve synthesis method mainly includes a dynamic hydrothermal crystallization method and a static crystallization method, but the methods all have problems such as uneven pre-gel of ZSM-5 molecular sieve, long synthesis cycle and single pore structure, which seriously restrict the application performance of ZSM-5 molecular sieve such as catalysis and adsorption. Now, for the treatment of long crystallization cycle and single pore structure in the synthesis process of ZSM-5 molecular sieve, adding seed, hard template method or acid dealumination / alkali desiliconization method are mostly used. The above purposes are to shorten the crystallization time of molecular sieve to promote the generation of multi-level pore structure, thereby improving the production efficiency of multi-level pore ZSM-5 molecular sieve. However, in the preparation process, there are still inapplicable characteristics such as difficulty in strengthening, uneven particle size, serious damage to the molecular sieve skeleton and difficulty in controlling the structure-oriented function.

[0004] CN117566754A discloses a hollow mesoporous ZSM-5 molecular sieve with uniform and adjustable pore size and a preparation method thereof. The molecular sieve is prepared under the conditions of a silicon-aluminum ratio of 40, a reaction temperature of 160-180°C and a crystallization time of 72 hours, wherein the structure directing agent tetrapropylammonium hydroxide (TPA) + With sodium carbonate Na + The ratio is 1.35-54, and 1M ammonium nitrate solution is used for ammonium exchange three times. However, the preparation method of ZSM-5 molecular sieve disclosed therein has the problems of long crystallization time, large amount of tetrapropylammonium hydroxide addition, and exchange with high-concentration ammonium solution. On the one hand, high amount of organic ammonium added is easy to be entrained into the molecular sieve product, and on the other hand, ammonium exchange will affect the skeleton structure of the material, thus seriously restricting the industrial production synthesis and back-end large-scale application of multi-level pore molecular sieves.

[0005] CN117430128A discloses a preparation method and application of a copper-doped ZSM-5 zeolite molecular sieve containing a mesoporous structure. The ZSM-5 zeolite molecular sieve containing a mesoporous structure is prepared by an in-situ doping hydrothermal method. Tetraethyl orthosilicate, aluminum sulfate and copper salt are used as raw materials. In the presence of a quaternary ammonium salt template, the copper-doped ZSM-5 zeolite molecular sieve containing a mesoporous structure is obtained. In the method, 1 g of tetraethyl orthosilicate corresponds to 0.01 to 1.5 g of quaternary ammonium salt, the crystallization time is 1 to 10 days, and the specific surface area is 353-422 m 2 / g, and the silicon-aluminum ratio is 10:1 to 80:1. However, the disclosed method for preparing copper-doped ZSM-5 zeolite molecular sieves containing mesoporous structures has the problems of long crystallization time, low specific surface area and silicon-aluminum ratio, and poor quaternary ammonium salt induction effect, which seriously affects the green and efficient synthesis of multi-level pore ZSM-5 molecular sieves.

[0006] Therefore, how to provide a simple and efficient multi-level porous nano ZSM-5 molecular sieve synthesis device, and further provide a multi-level porous nano ZSM-5 molecular sieve with controllable pore structure, good performance, small size and uniformity, has become an urgent problem that technicians in this field need to solve. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a molecular sieve synthesis device and a method for preparing a multi-level porous nano ZSM-5 molecular sieve using the same. The molecular sieve synthesis device includes a pre-gel and crystallization reaction coordination device, and an ultrasonic generator and a microwave generator are arranged inside the pre-gel and crystallization reaction coordination device, which can achieve highly uniform pre-gel reaction mixing between raw materials, and can also achieve rapid crystallization and induction of multi-level pore structure, further achieve directional regulation of the particle size and pore structure of the molecular sieve, effectively control the particle size and production efficiency of the molecular sieve, and have good industrial application prospects.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a molecular sieve synthesis device, the molecular sieve synthesis device comprises a pre-gel and crystallization reaction coordination device, the pre-gel and crystallization reaction coordination device is provided with a first feed port, a second feed port and a discharge port, the first feed port is connected to a first raw material preparation unit, the second feed port is connected to a second raw material preparation unit; the discharge port is connected to a solid-liquid separation device;

[0010] Wherein, at least one ultrasonic generator and at least one microwave generator are arranged inside the pre-gel and crystallization reaction coordination device;

[0011] The ultrasonic generator is arranged on the inner side wall of the pre-gel and crystallization reaction coordination device;

[0012] The microwave generator is arranged in the side wall interlayer of the pre-gel and crystallization reaction coordination device.

[0013] It should be noted that the side wall of the pre-gel and crystallization reaction collaborative device of the present invention is divided into a two-layer structure, including an inner side wall and an outer side wall. The ultrasonic generator is arranged on the inner side wall, which can realize high-energy vibration strong shear and shock wave to jointly disperse and crush the agglomerated particles of the mixed slurry. The microwave generator is arranged in the side wall interlayer between the inner side wall and the outer side wall, and can use high-frequency electromagnetic waves to quickly increase the temperature of the reaction system to achieve rapid crystallization of the molecular sieve.

[0014] It should be noted that when the number of ultrasonic generators is ≥2, in the same plane where the ultrasonic generators are located, the distribution between the two is not limited, and a uniform distribution method or a non-uniform distribution method can be adopted, and a uniform distribution method is preferably adopted; when the number of microwave generators is ≥2, in the same plane where the microwave generators are located, the distribution between the two is not limited, and a uniform distribution method or a non-uniform distribution method can be adopted, and a uniform distribution method is preferably adopted.

[0015] The pre-gel and crystallization reaction synergistic device of the present invention is used to make the raw materials undergo pre-gel reaction and crystallization reaction. Among them, the ultrasonic generator uses the high-frequency vibration of ultrasound to achieve rapid mixing and collision between the raw materials, promote the pre-gel reaction, and form a large number of uniformly dispersed molecular sieve precursors. The microwave generator can quickly heat up so that the reaction temperature quickly reaches the temperature required for crystallization, and quickly realize the molecular sieve required for precursor crystallization synthesis. In addition, the microwave generator can achieve uniform internal heating, realize uniform growth of the molecular sieve and directional regulation of efficient crystal growth, and further improve the particle size and production efficiency of the molecular sieve; the first raw material preparation unit and the second raw material preparation unit can effectively regulate the concentration components of the raw materials; the solid-liquid separation device realizes solid-liquid separation of the mixed slurry after the crystallization reaction is completed, and obtains a multi-level porous nano ZSM-5 molecular sieve solid product.

[0016] Taking the bottom of the pregel and crystallization reaction coordinated device as a reference, the vertical height of the ultrasonic generator from the bottom is 1 / 3 to 2 / 3 of the overall height of the pregel and crystallization reaction coordinated device, such as 1 / 3, 1 / 2 or 2 / 3.

[0017] Preferably, with the bottom of the pregel and crystallization reaction coordinated device as a reference, the vertical height of the microwave generator from the bottom is 1 / 3 to 2 / 3 of the overall height of the pregel and crystallization reaction coordinated device, such as 1 / 3, 1 / 2 or 2 / 3.

[0018] It should be noted that the height of the raw materials in the pre-gel and crystallization reaction coordinated device of the present invention needs to be higher than the vertical height of the ultrasonic generator and the microwave generator from the bottom of the pre-gel and crystallization reaction coordinated device to ensure that the raw materials undergo sufficient pre-gel reaction and crystallization reaction.

[0019] Preferably, the first raw material preparation unit comprises a first preparation tank body; a first heating device is arranged on the outer wall of the first preparation tank body, and a first stirring device is arranged inside the first preparation tank body.

[0020] Preferably, the second raw material preparation unit comprises a second preparation tank body; a second heating device is arranged on the outer wall of the second preparation tank body, and a second stirring device is arranged inside the second preparation tank body.

[0021] Preferably, a third stirring device is provided inside the pre-gel and crystallization reaction coordinated device.

[0022] Preferably, a first flow control unit is provided between the first feed inlet and the first raw material preparation unit.

[0023] Preferably, the first flow control unit includes a first flow controller and a first feeding pump, the first flow controller is arranged between the first feeding pump and the first feeding port, and the first feeding pump is connected to the first raw material preparation unit.

[0024] Preferably, a second flow control unit is provided between the second feed inlet and the second raw material preparation unit.

[0025] Preferably, the second flow control unit includes a second flow controller and a second loading pump, the second flow controller is arranged between the second loading pump and the second feed port, and the second loading pump is connected to the second raw material preparation unit.

[0026] The first flow control unit and the second flow control unit of the present invention can play a role of precise control according to production capacity and crystallization efficiency.

[0027] Preferably, the first feed inlet and the second feed inlet are provided with nozzles facing the interior of the pre-gel and crystallization reaction coordinated device.

[0028] Preferably, the first feed inlet and the second feed inlet are arranged opposite to each other and have the same vertical height.

[0029] Preferably, taking the bottom of the pre-gel and crystallization reaction coordinated device as a reference, the vertical heights of the first feed port and the second feed port from the bottom are independently 1 / 3 to 2 / 3 of the overall height of the pre-gel and crystallization reaction coordinated device, for example, 1 / 3, 1 / 2 or 2 / 3.

[0030] In a second aspect, the present invention further provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve using the molecular sieve synthesis device described in the first aspect, the preparation method comprising the following steps:

[0031] A silicon-containing composite solution containing a structure directing agent is prepared in a first raw material preparation unit, and an aluminum-containing solution is prepared in a second raw material preparation unit; an ultrasonic generator is turned on, and a microwave generator is kept turned off, and the silicon-containing composite solution containing a structure directing agent and the aluminum-containing solution are respectively injected into a pregel and crystallization reaction synergistic device through a first feed port and a second feed port to carry out a pregel reaction; after the pregel reaction is completed, the ultrasonic generator is turned off, and the microwave generator is turned on to carry out a crystallization reaction; the obtained mixed slurry enters a solid-liquid separation device through a discharge port, and a multi-level porous nano ZSM-5 molecular sieve is obtained through solid-liquid separation.

[0032] In the raw material mixing step, the present invention controls the particle size distribution and pore structure distribution of the multi-level porous nano ZSM-5 molecular sieve in the mixed slurry by adjusting the temperature of the pregel reaction in the pregel and crystallization reaction cooperative device, and the temperature and time of the crystallization reaction. At the same time, it can effectively shorten the crystallization time and improve the uniformity of the pore structure distribution of the multi-level porous nano ZSM-5 molecular sieve, which is conducive to continuous production.

[0033] Preferably, the method for preparing the silicon-containing composite solution containing a structure directing agent comprises: first preparing a silicon-containing solution, and then adding the structure directing agent.

[0034] Preferably, the preparation temperature of the silicon-containing solution is 0-100°C, for example, 0°C, 20°C, 40°C, 60°C, 80°C or 100°C.

[0035] Preferably, the preparation temperature of the aluminum-containing solution is 0-100°C, for example, 0°C, 20°C, 40°C, 60°C, 80°C or 100°C.

[0036] Preferably, the silicon-containing solution comprises any one of sodium silicate solution, silica sol solution, white carbon black solution, ethyl orthosilicate solution or silicon-containing solution of bulk solid waste alkali desiliconization, or a combination of at least two thereof.

[0037] Preferably, the structure directing agent comprises an organic ammonium compound.

[0038] Preferably, the organic amine compound includes any one of cetyltrimethylammonium bromide, n-butylamine or tetrapropylammonium hydroxide, or a combination of at least two thereof.

[0039] In the present invention, a structure directing agent is added to the raw material, and combined with the microwave effect generated by the microwave generator, a multi-level pore structure can be formed by direction control, and the crystallization time is greatly shortened, and the particle size is small.

[0040] Preferably, the molar ratio of the structure directing agent to the SiO2 in the silicon-containing solution is (0.001-1):1, for example, 0.001:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.5:1 or 1:1, etc.

[0041] Preferably, the aluminum-containing solution includes any one of aluminum sulfate solution, aluminum nitrate solution, aluminum chloride solution, sodium aluminate solution, aluminum isopropoxide solution, aluminum sulfide solution, aluminum bromide solution, aluminum iodide solution or pseudo-boehmite solution, or a combination of at least two thereof.

[0042] It should be noted that the present invention can prepare multi-level porous nano ZSM-5 molecular sieves with different silicon-aluminum ratios, and the concentrations of the silicon-containing solution and the aluminum-containing solution can be adaptively selected and adjusted according to actual needs.

[0043] Preferably, the injection flow rate of the silicon-containing solution is 0.1-10 L / min, for example, 0.1 L / min, 0.3 L / min, 0.5 L / min, 0.7 L / min, 1 L / min, 3 L / min, 5 L / min, 7 L / min, 9 L / min or 10 L / min.

[0044] Preferably, the injection flow rate of the aluminum-containing solution is 0.1-10 L / min, for example, 0.1 L / min, 0.3 L / min, 0.5 L / min, 0.7 L / min, 1 L / min, 3 L / min, 5 L / min, 7 L / min, 9 L / min or 10 L / min.

[0045] Preferably, the temperature of the pre-gel reaction is 0-100°C, such as 0°C, 20°C, 40°C, 60°C, 80°C or 100°C.

[0046] Preferably, the pre-gel reaction time is 1 to 3600 s, for example, 1 s, 5 s, 50 s, 100 s, 500 s, 1000 s, 1500 s, 2000 s, 2500 s or 3000 s.

[0047] In the present invention, the pre-gel reaction time is 1 to 3600 seconds, which can ensure that the pre-gel reaction is fully carried out and the synthesis efficiency of the molecular sieve is high; if the pre-gel reaction time is too long, the pre-reaction between the silicon and aluminum components is excessive, resulting in a significant decrease in the synthesis efficiency of the molecular sieve; if the pre-gel reaction time is too short, the effective collision between the silicon and aluminum components cannot be fully achieved, and it is difficult for the gelation reaction to fully occur.

[0048] Preferably, the temperature of the crystallization reaction is 150-200°C, for example, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C or 200°C.

[0049] In the present invention, the temperature of the crystallization reaction is 150-200°C, which can promote the efficient crystal growth of the molecular sieve and improve the production efficiency of the multi-level porous nano ZSM-5 molecular sieve; if the temperature of the crystallization reaction is too high, the growth rate of the molecular sieve crystal is greater than the nucleation rate, thereby inhibiting the nucleation of the crystal particles and making it difficult to form a large number of nano-scale crystals; if the temperature of the crystallization reaction is too low, the aluminum oxide tetrahedron and silicon oxide tetrahedron units are difficult to form effectively, inhibiting the condensation reaction of the two types of structures, significantly slowing down the growth rate of the crystal nucleus, and failing to form a molecular sieve product with high crystallinity.

[0050] Preferably, the crystallization reaction time is 0.2 to 72 h, for example, 0.2 h, 0.5 h, 1 h, 3 h, 5 h, 7 h, 9 h, 12 h, 24 h, 36 h, 48 h or 72 h.

[0051] In the present invention, the crystallization reaction time is 0.2 to 72 hours, which can ensure that the molecular sieve is completely crystallized and has a high purity. If the crystallization reaction time is too long, the concentration of the silicon and aluminum components in the reaction environment is converted into an unsaturated state, and the metastable crystalline molecular sieve is prone to crystallization transformation, producing other types of structural molecular sieves to reduce the purity of the product. If the crystallization reaction time is too short, the crystallization growth process of the molecular sieve particles is not fully guaranteed, resulting in a low degree of crystallization of the molecular sieve crystals, and even incomplete crystallization of the molecular sieve.

[0052] It should be noted that the present invention does not limit the reaction mode of the crystallization reaction, and the reaction can be carried out under static conditions, that is, without stirring, or under dynamic conditions, that is, under stirring.

[0053] As a preferred technical solution, the preparation method comprises the following steps:

[0054] A silicon-containing solution is first prepared in a first mixing tank at 0-100° C., a structure directing agent is added, and the mixture is stirred to obtain a silicon-containing composite solution containing the structure directing agent. An aluminum-containing solution is prepared in a second mixing tank at 0-100° C.; an ultrasonic generator and a third stirring device are turned on, and a microwave generator is kept turned off. The silicon-containing composite solution containing the structure directing agent is sequentially injected into the pregel and crystallization reaction synergistic device through a first feeding pump and a first flow controller at a flow rate of 0.1-10 L / min through a first feeding port. The aluminum-containing solution is sequentially injected into the pregel and crystallization reaction synergistic device through a second feeding pump and a second flow controller. The pregel and crystallization reaction synergistic device is injected into the pregel and crystallization reaction synergistic device through the second feed port at a flow rate of 0.1 to 10 L / min, and the pregel is performed at 0 to 100 ° C for 1 to 3600 seconds; after the pregel reaction is completed, the ultrasonic generator is turned off, the microwave generator is turned on, the temperature of the reaction system is increased to 150 to 200 ° C, and the crystallization reaction is performed for 0.2 to 72 hours to form a mixed slurry; the obtained mixed slurry enters the solid-liquid separation device through the discharge port, and the liquid after separation is evaporated and concentrated for secondary crystallization and recycling, and the solid after separation is dried to obtain a multi-level porous nano ZSM-5 molecular sieve;

[0055] Wherein, the molar ratio of the structure directing agent to the SiO2 in the silicon-containing solution is (0.001-1):1.

[0056] Compared with the prior art, the present invention has at least the following beneficial effects:

[0057] 1) The molecular sieve synthesis device provided by the present invention can achieve highly uniform pre-gel reaction mixing between raw materials, and can also achieve rapid crystallization and induction of multi-level pore structure, further achieve directional regulation of particle size and pore structure of molecular sieve, effectively control the particle size and production efficiency of molecular sieve, and has good industrial application prospects;

[0058] 2) The multi-level pore nano ZSM-5 molecular sieve prepared by the molecular sieve synthesis device of the present invention can not only control the particle size and pore structure size of the molecular sieve, but also realize the continuous feeding of raw materials, so that the pre-gel reaction and crystallization reaction can be quickly carried out in the pre-gel and crystallization reaction synergistic device, promote the efficient crystal growth of the molecular sieve, and improve the production efficiency of the multi-level pore nano ZSM-5 molecular sieve;

[0059] 3) The molecular sieve synthesis device provided by the present invention can prepare a multi-level porous nano ZSM-5 molecular sieve in the form of white powder with high purity, uniform particle size distribution, D50 < 350nm, and a specific surface area of ​​500-700m 2 / g, the particle size is small, the chemical reaction is more complete, the active sites are easy to reach, and the reaction efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1The molecular sieve synthesis device provided in Example 1 of the present invention;

[0061] Figure 2 The molecular sieve synthesis device provided in Example 2 of the present invention;

[0062] Figure 3 It is the molecular sieve synthesis device provided in Comparative Example 1 of the present invention;

[0063] Among them, 1-first mixing tank, 2-first feeding pump, 3-first flow controller, 4-second mixing tank, 5-second feeding pump, 6-second flow controller, 7-pre-gel and crystallization reaction coordination device, 8-solid-liquid separation device, 9-first feed port, 10-second feed port, 11-discharge port, 12-pre-gel reaction device, 13-crystallization reaction device, 14-crystallization reaction device discharge port, 15-transport pump, 16-crystallization reaction device feed port. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0065] Example 1

[0066] This embodiment provides a molecular sieve synthesis device, such as Figure 1As shown, the molecular sieve synthesis device includes a pregel and crystallization reaction coordination device 7, the pregel and crystallization reaction coordination device 7 is provided with a first feed port 9, a second feed port 10 and a discharge port 11, the first feed port 9 is connected to the first raw material preparation unit, and the second feed port 10 is connected to the second raw material preparation unit; the discharge port 11 is connected to the solid-liquid separation device 8; an ultrasonic generator and a microwave generator are arranged inside the pregel and crystallization reaction coordination device 7; the first raw material preparation unit includes a first preparation tank body 1; a first heating device is arranged on the outer wall of the first preparation tank body 1, and a first stirring device is arranged inside the first preparation tank body 1; the second raw material preparation unit includes a second preparation tank body 4; a second heating device is arranged on the outer wall of the second preparation tank body 4, and a second stirring device is arranged inside the second preparation tank body 4; a third stirring device is arranged inside the pregel and crystallization reaction coordination device 7; a first flow control unit is arranged between the first feed port 9 and the first raw material preparation unit ; The first flow control unit includes a first flow controller 3 and a first feeding pump 2, the first flow controller 3 is arranged between the first feeding pump 2 and the first feeding port 9, and the first feeding pump 2 is connected to the first mixing tank 1; a second flow control unit is arranged between the second feeding port 10 and the second raw material mixing unit; the second flow control unit includes a second flow controller 6 and a second feeding pump 5, the second flow controller 6 is arranged between the second feeding pump 5 and the second feeding port 10, and the second feeding pump 5 is connected to the second mixing tank 4, and the first feeding port 9 and the second feeding port 10 are provided with nozzles facing the interior of the pregel and crystallization reaction collaborative device 7; the first feeding port 9 and the second feeding port 10 are arranged opposite to each other and have the same vertical height; taking the bottom of the pregel and crystallization reaction collaborative device as a reference, the vertical height of the first feeding port 9 and the second feeding port 10 from the bottom is 1 / 2 of the overall height of the pregel and crystallization reaction collaborative device;

[0067] Among them, three ultrasonic generators and three microwave generators are arranged inside the pregel and crystallization reaction collaborative device 7, and the ultrasonic generator is arranged on the inner side wall of the pregel and crystallization reaction collaborative device 7; taking the bottom of the pregel and crystallization reaction collaborative device 7 as a reference, the vertical height of the ultrasonic generator from the bottom is 1 / 3 of the overall height of the pregel and crystallization reaction collaborative device 7; the three ultrasonic generators are evenly distributed on the inner side wall, and the interval between any two is 120°; the microwave generator is arranged in the side wall interlayer of the pregel and crystallization reaction collaborative device 7; taking the bottom of the pregel and crystallization reaction collaborative device 7 as a reference, the vertical height of the microwave generator from the bottom is 1 / 2 of the overall height of the pregel and crystallization reaction collaborative device 7; the three microwave generators are evenly distributed in the side wall interlayer, and the interval between any two is 120°.

[0068] Example 2

[0069] This embodiment provides a molecular sieve synthesis device, such as Figure 2 As shown, the difference between the molecular sieve synthesis device provided in this embodiment and Example 1 is that the molecular sieve synthesis device is not provided with the first flow controller 3 and the second flow controller 6, the first loading pump 2 is directly connected to the first feed port 9, and the second loading pump 5 is directly connected to the second feed port 10, and the remaining devices and connection relationships remain the same as those in Example 1.

[0070] Comparative Example 1

[0071] This comparative example provides a molecular sieve synthesis device, such as Figure 3 As shown, the molecular sieve synthesis device provided in this comparative example is different from that in Example 1 in that the molecular sieve synthesis device includes a pre-gel reaction device 12, the pre-gel reaction device 12 is provided with a first feed port 9, a second feed port 10 and a discharge port 11, the discharge port 11 is connected to a crystallization reaction device 13, a delivery pump 15 is arranged between the discharge port 11 and the feed port 16 of the crystallization reaction device, and the discharge port 14 of the crystallization reaction device is connected to a solid-liquid separation device 8; an ultrasonic generator and a third stirring device are arranged inside the pre-gel reaction device 12; nozzles are arranged toward the inside of the pre-gel reaction device 7 by the first feed port 9 and the second feed port 10; a microwave generator and a fourth stirring device are arranged inside the crystallization reaction device 13;

[0072] Wherein, the side walls of the pre-gel reaction device 12 and the crystallization reaction device 13 are independently two-layer structures, including an inner side wall and an outer side wall; three ultrasonic generators are arranged inside the pre-gel reaction device 12, and the ultrasonic generators are arranged on the inner side wall of the pre-gel reaction device 12; with the bottom of the pre-gel reaction device 12 as a reference, the vertical height of the ultrasonic generator from the bottom is 1 / 3 of the overall height of the pre-gel reaction device 12; the three ultrasonic generators are evenly distributed on the inner side wall, and the interval between two is 120°; three microwave generators are arranged inside the crystallization reaction device 13, and the microwave generators are arranged in the side wall interlayer between the inner side wall and the outer side wall of the crystallization reaction device 13; with the bottom of the crystallization reaction device 13 as a reference, the vertical height of the microwave generator from the bottom is 1 / 2 of the overall height of the crystallization reaction device 13; three microwave generators are evenly distributed in the side wall interlayer, and the interval between two is 120°, and the remaining devices and connection relationships remain the same as those in Example 1.

[0073] Application Example 1

[0074] This application example provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve, the preparation method uses the molecular sieve synthesis device described in Example 1, and the preparation method includes the following steps:

[0075] A silica sol solution is prepared in the first mixing tank at 45°C, and then tetrapropylammonium hydroxide is added, the molar ratio of tetrapropylammonium hydroxide to SiO2 in the silica sol solution is 0.03:1, and the silica sol solution containing tetrapropylammonium hydroxide is obtained by stirring. A pseudo-boehmite solution is prepared in the second mixing tank at 45°C; the ultrasonic generator and the third stirring device are turned on, and the microwave generator is kept turned off. The silica sol solution containing tetrapropylammonium hydroxide is sequentially injected into the pre-gel and crystallization reaction synergistic device through the first feeding port at a flow rate of 5L / min via the first feeding pump and the first flow controller. The pseudo-boehmite solution is sequentially injected into the pre-gel and crystallization reaction coordinated device through the second feeding port at a flow rate of 5L / min via the second feeding pump and the second flow controller, and pre-gelled for 1800s at 45°C; after the gel reaction is completed, the ultrasonic generator is turned off, the microwave generator is turned on, the reaction system is raised to 170°C, and the crystallization reaction is carried out for 4h under stirring to form a mixed slurry, and the obtained mixed slurry enters the solid-liquid separation device through the discharge port, is centrifuged, and the separated liquid is evaporated, concentrated, secondary crystallized and recycled, and the separated solid is dried to obtain a multi-level porous nano ZSM-5 molecular sieve.

[0076] Application Example 2

[0077] This application example provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve, the preparation method uses the molecular sieve synthesis device described in Example 1, and the preparation method includes the following steps:

[0078] A white carbon black solution was prepared in a first mixing tank at 25°C, and then n-butylamine was added, the molar ratio of n-butylamine to SiO2 in the white carbon black solution was 0.001:1, and the white carbon black solution containing n-butylamine was obtained by stirring. An isopropanol aluminum solution was prepared in a second mixing tank at 25°C; an ultrasonic generator and a third stirring device were turned on, and a microwave generator was kept turned off. The white carbon black solution containing n-butylamine was sequentially injected into the pre-gel and crystallization reaction synergistic device through the first feeding pump and the first flow controller at a flow rate of 1 L / min through the first feeding port. The isopropanol aluminum solution was sequentially injected into the pre-gel and crystallization reaction synergistic device through the first feeding pump and the first flow controller at a flow rate of 1 L / min. The second feeding pump and the second flow controller are injected into the pre-gel and crystallization reaction collaborative device through the second feed port at a flow rate of 1L / min, and the pre-gel is carried out for 3600s at 25°C. After the gel reaction is completed, the ultrasonic generator and the third stirring device are turned off, the microwave generator is turned on, the reaction system is raised to 150°C, and the crystallization reaction is carried out for 72h under static conditions to form a mixed slurry. The obtained mixed slurry enters the solid-liquid separation device through the discharge port, and is centrifuged. The separated liquid is evaporated and concentrated for secondary crystallization and recycling, and the separated solid is dried to obtain a multi-level porous nano ZSM-5 molecular sieve.

[0079] Application Example 3

[0080] This application example provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve, the preparation method uses the molecular sieve synthesis device described in Example 1, and the preparation method includes the following steps:

[0081] A sodium silicate solution is prepared in a first mixing tank at 50° C., and then cetyl trimethyl ammonium bromide is added, the molar ratio of cetyl trimethyl ammonium bromide to SiO2 in the sodium silicate solution is 1:1, and the sodium silicate solution containing cetyl trimethyl ammonium bromide is obtained by stirring. A sodium aluminate solution is prepared in a second mixing tank at 50° C.; an ultrasonic generator and a third stirring device are turned on, and a microwave generator is kept turned off. The sodium silicate solution containing cetyl trimethyl ammonium bromide is sequentially fed through a first feeding pump and a first flow controller, and injected into the pregel and crystallization reaction coordination system through a first feed port at a flow rate of 10 L / min. In the same device, the sodium aluminate solution is sequentially injected into the pre-gel and crystallization reaction collaborative device through the second feeding port via the second feeding pump and the second flow controller at a flow rate of 10L / min, and pre-gelled for 5s at 100°C; after the gel reaction is completed, the ultrasonic generator is turned off, the microwave generator is turned on, the reaction system is raised to 200°C, and the crystallization reaction is carried out for 0.2h under stirring to form a mixed slurry, and the obtained mixed slurry enters the solid-liquid separation device through the discharge port for centrifugal separation, the separated liquid is evaporated and concentrated for secondary crystallization and recycling, and the separated solid is dried to obtain a multi-level porous nano ZSM-5 molecular sieve.

[0082] Application Example 4

[0083] This application example provides a method for preparing multi-level porous nano ZSM-5 molecular sieves. The preparation method uses the molecular sieve synthesis device described in Example 1. The difference between this application example and Application Example 1 is that the pre-gel time is 4500s, and the rest of the preparation method and parameters are consistent with Application Example 1.

[0084] Application Example 5

[0085] This application example provides a method for preparing multi-level porous nano ZSM-5 molecular sieves. The preparation method uses the molecular sieve synthesis device described in Example 1. The difference between this application example and Application Example 1 is that the temperature of the crystallization reaction is 130°C, and the rest of the preparation method and parameters are consistent with Application Example 1.

[0086] Application Example 6

[0087] This application example provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve. The preparation method uses the molecular sieve synthesis device described in Example 1. The difference between this application example and Application Example 1 is that the temperature of the crystallization reaction is 220°C, and the rest of the preparation method and parameters are consistent with Application Example 1.

[0088] Application Example 7

[0089] This application example provides a method for preparing multi-level porous nano ZSM-5 molecular sieves. The preparation method uses the molecular sieve synthesis device described in Example 1. The difference between this application example and Application Example 1 is that the crystallization reaction time is 80 hours, and the rest of the preparation method and parameters are consistent with Application Example 1.

[0090] Application Example 8

[0091] This application example provides a method for preparing multi-level porous nano ZSM-5 molecular sieves. The preparation method uses the molecular sieve synthesis device described in Example 1. The difference between this application example and Application Example 1 is that the crystallization reaction time is 0.1h, and the rest of the preparation method and parameters are consistent with Application Example 1.

[0092] Application Example 9

[0093] This application example provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve, the preparation method uses the molecular sieve synthesis device described in Example 2, the difference between the preparation method and Application Example 1 is that the silica sol solution containing tetrapropylammonium hydroxide is injected into the pregel and crystallization reaction coordinated device through the first feed port via the first feeding pump, the pseudo-boehmite solution is injected into the pregel and crystallization reaction coordinated device through the second feeding port via the second feeding pump, and the rest of the preparation method and parameters are consistent with Application Example 1.

[0094] Comparative application example 1

[0095] This comparative application example provides a method for preparing a multi-level porous nano ZSM-5 molecular sieve, the preparation method using the molecular sieve synthesis device described in Comparative Example 1, the preparation method comprises the following steps:

[0096] A silica sol solution was prepared in a first mixing tank at 45°C, and tetrapropylammonium hydroxide was added, the molar ratio of tetrapropylammonium hydroxide to SiO2 in the silica sol solution was 0.03:1, and the silica sol solution containing tetrapropylammonium hydroxide was obtained by stirring. A pseudo-boehmite solution was prepared in a second mixing tank at 45°C; an ultrasonic generator and a third stirring device were turned on, and the silica sol solution containing tetrapropylammonium hydroxide was sequentially injected into the pre-gel reaction device through the first feeding port through the first feeding pump and the first flow controller at a flow rate of 5L / min. The pseudo-boehmite solution was sequentially injected into the pre-gel reaction device through the second feeding pump and the second flow controller. , injected into the pre-gel reaction device through the second feed port at a flow rate of 5L / min, and pre-gelled for 1800s at 45°C; after the gel reaction is completed, the reaction product is sequentially introduced into the crystallization reaction device through the discharge port, the delivery pump and the feed port of the crystallization reaction device, the microwave generator and the fourth stirring device are turned on, the reaction system is raised to 170°C, and the crystallization reaction is carried out for 4h under stirring to form a mixed slurry, and the obtained mixed slurry is introduced into the solid-liquid separation device through the discharge port of the crystallization reaction device, centrifuged, the separated liquid is evaporated and concentrated for secondary crystallization and recycling, and the separated solid is dried to obtain a multi-level porous nano ZSM-5 molecular sieve.

[0097] The multi-level porous nano ZSM-5 molecular sieves prepared in Application Examples 1 to 9 and Comparative Application Example 1 were tested for particle size using a Malvern laser particle size analyzer and for specific surface area using a nitrogen physical adsorption and desorption instrument. The specific test results are shown in Table 1.

[0098] Table 1

[0099] project Particle size D50(nm) <![CDATA[Specific surface area (m 2 / g)]]> Application Example 1 120 680 Application Example 2 230 580 Application Example 3 340 500 Application Example 4 480 420 Application Example 5 670 320 Application Example 6 770 310 Application Example 7 790 300 Application Example 8 820 290 Application Example 9 850 270 Comparative application example 1 580 390

[0100] The test results show that:

[0101] (1) It can be seen from Application Examples 1-3 that the multi-level porous nano ZSM-5 molecular sieve prepared by the molecular sieve synthesis device provided in Example 1 of the present invention is a white powder with high purity and uniform particle size distribution, D50 < 350nm, and a specific surface area of ​​500-700m 2 / g, D50 and specific surface area are within this range, the particle size of the hierarchical nano ZSM-5 molecular sieve is small, the chemical reaction is more complete, the active sites are easy to reach, and the reaction efficiency is high;

[0102] (2) It can be seen from Application Examples 1 and 4 that the present invention limits the time of the pre-gel reaction to 1 to 3600 s, which can better achieve the pre-gel reaction, make the raw materials fully mixed and the synthesis efficiency of the molecular sieve high, and the prepared molecular sieve has a suitable particle size and specific surface area;

[0103] (3) It can be seen from Application Examples 1 and 5-6 that the present invention limits the crystallization temperature to 150-200°C, which can promote the uniform and efficient crystal growth of the molecular sieve, thereby improving the production efficiency of the multi-level porous nano ZSM-5 molecular sieve, and the prepared molecular sieve has a suitable particle size and specific surface area;

[0104] (4) It can be seen from Application Examples 1 and 7-8 that the present invention limits the crystallization time to 0.2 to 72 h, which can ensure that the molecular sieve is completely crystallized and has a high purity. The prepared multi-level porous nano ZSM-5 molecular sieve has a suitable particle size and specific surface area;

[0105] (5) It can be seen from Application Examples 1 and 9 that if the flow control device is not used in the present invention, the reaction molar ratio of the silicon-aluminum solution cannot be accurately controlled, and thus the multi-level porous nano ZSM-5 molecular sieve with a specific particle size and specific surface area cannot be obtained by reaction;

[0106] (6) It can be seen from Application Example 1 and Comparative Application Example 1 that the present invention separates the pre-gel reaction and the crystallization reaction in different devices, which increases the number of reaction devices. At the same time, it is difficult to transfer the high-viscosity pre-gel to the crystallization reaction device. A large amount of gel slurry is easily lost in the equipment and pipelines, which is easy to clog the delivery pump, thereby reducing production efficiency, thereby increasing the particle size of the prepared multi-level porous nano ZSM-5 molecular sieve and reducing the specific surface area.

[0107] In summary, the molecular sieve synthesis device of the present invention includes a pre-gel and crystallization reaction synergistic device, which can achieve highly uniform pre-gel reaction mixing between raw materials, while also achieving rapid crystallization and induction of multi-level pore structure, further achieving directional regulation of the particle size and pore structure of the molecular sieve, and effectively controlling the particle size and production efficiency of the molecular sieve.

[0108] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A molecular sieve synthesis device, characterized in that: The molecular sieve synthesis device comprises a pre-gel and crystallization reaction coordination device, the pre-gel and crystallization reaction coordination device is provided with a first feed port, a second feed port and a discharge port, the first feed port is connected to a first raw material preparation unit, the second feed port is connected to a second raw material preparation unit; the discharge port is connected to a solid-liquid separation device; Wherein, at least one ultrasonic generator and at least one microwave generator are arranged inside the pre-gel and crystallization reaction coordination device; The ultrasonic generator is arranged on the inner side wall of the pre-gel and crystallization reaction coordination device; The microwave generator is arranged in the side wall interlayer of the pre-gel and crystallization reaction coordination device.

2. The molecular sieve synthesis device according to claim 1, characterized in that: Taking the bottom of the pre-gel and crystallization reaction coordinated device as a reference, the vertical height of the ultrasonic generator from the bottom is 1 / 3 to 2 / 3 of the overall height of the pre-gel and crystallization reaction coordinated device; Preferably, taking the bottom of the pregel and crystallization reaction coordinated device as a reference, the vertical height of the microwave generator from the bottom is 1 / 3 to 2 / 3 of the overall height of the pregel and crystallization reaction coordinated device; Preferably, the first raw material preparation unit comprises a first preparation tank; a first heating device is arranged on the outer wall of the first preparation tank, and a first stirring device is arranged inside the first preparation tank; Preferably, the second raw material preparation unit comprises a second preparation tank; a second heating device is arranged on the outer wall of the second preparation tank, and a second stirring device is arranged inside the second preparation tank; Preferably, a third stirring device is provided inside the pre-gel and crystallization reaction coordinated device.

3. The molecular sieve synthesis device according to claim 1 or 2, characterized in that: A first flow control unit is provided between the first feed inlet and the first raw material preparation unit; Preferably, the first flow control unit includes a first flow controller and a first feeding pump, the first flow controller is arranged between the first feeding pump and the first feeding port, and the first feeding pump is connected to the first raw material preparation unit.

4. The molecular sieve synthesis device according to any one of claims 1 to 3, characterized in that: A second flow control unit is provided between the second feed inlet and the second raw material preparation unit; Preferably, the second flow control unit includes a second flow controller and a second loading pump, the second flow controller is arranged between the second loading pump and the second feed port, and the second loading pump is connected to the second raw material preparation unit.

5. The molecular sieve synthesis device according to any one of claims 1 to 4, characterized in that: The first feed inlet and the second feed inlet are provided with nozzles toward the interior of the pre-gel and crystallization reaction coordination device; Preferably, the first feed inlet and the second feed inlet are arranged opposite to each other and have the same vertical height; Preferably, taking the bottom of the pregel and crystallization reaction coordinated device as a reference, the vertical heights of the first feed inlet and the second feed inlet from the bottom are independently 1 / 3 to 2 / 3 of the overall height of the pregel and crystallization reaction coordinated device.

6. A method for preparing multi-level porous nano ZSM-5 molecular sieve using the molecular sieve synthesis device according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: A silicon-containing composite solution containing a structure directing agent is prepared in a first raw material preparation unit, and an aluminum-containing solution is prepared in a second raw material preparation unit; an ultrasonic generator is turned on, and a microwave generator is kept turned off, and the silicon-containing composite solution containing a structure directing agent and the aluminum-containing solution are respectively injected into a pregel and crystallization reaction synergistic device through a first feed port and a second feed port to carry out a pregel reaction; after the pregel reaction is completed, the ultrasonic generator is turned off, and the microwave generator is turned on to carry out a crystallization reaction; the obtained mixed slurry enters a solid-liquid separation device through a discharge port, and a multi-level porous nano ZSM-5 molecular sieve is obtained through solid-liquid separation.

7. The method according to claim 6, characterized in that The method for preparing the silicon-containing composite solution containing a structure directing agent comprises: first preparing a silicon-containing solution, and then adding the structure directing agent; Preferably, the silicon-containing solution comprises any one of sodium silicate solution, silica sol solution, white carbon black solution, ethyl orthosilicate solution or silicon-containing solution of bulk solid waste alkali desiliconization, or a combination of at least two thereof; Preferably, the structure directing agent comprises an organic amine compound; Preferably, the organic amine compound includes any one or a combination of at least two of cetyltrimethylammonium bromide, n-butylamine or tetrapropylammonium hydroxide; Preferably, the molar ratio of the structure directing agent to the SiO2 in the silicon-containing solution is (0.001-1):

1.

8. The method according to claim 6 or 7, characterized in that: The aluminum-containing solution includes any one of aluminum sulfate solution, aluminum nitrate solution, aluminum chloride solution, sodium aluminate solution, aluminum isopropoxide solution, aluminum sulfide solution, aluminum bromide solution, aluminum iodide solution or pseudo-boehmite solution, or a combination of at least two thereof; Preferably, the injection flow rate of the silicon-containing solution is 0.1 to 10 L / min; Preferably, the injection flow rate of the aluminum-containing solution is 0.1 to 10 L / min.

9. The method according to any one of claims 6 to 8, characterized in that: The temperature of the pre-gel reaction is 0 to 100° C. Preferably, the pre-gel reaction time is 1 to 3600 s; Preferably, the temperature of the crystallization reaction is 150-200°C; Preferably, the crystallization reaction time is 0.2 to 72 hours.

10. The method according to any one of claims 6 to 9, characterized in that: The preparation method comprises the following steps: A silicon-containing solution is first prepared in a first mixing tank at 0-100° C., a structure directing agent is added, and the mixture is stirred to obtain a silicon-containing composite solution containing the structure directing agent. An aluminum-containing solution is prepared in a second mixing tank at 0-100° C.; an ultrasonic generator and a third stirring device are turned on, and a microwave generator is kept turned off. The silicon-containing composite solution containing the structure directing agent is sequentially injected into the pregel and crystallization reaction synergistic device through a first feeding pump and a first flow controller at a flow rate of 0.1-10 L / min through a first feeding port. The aluminum-containing solution is sequentially injected into the pregel and crystallization reaction synergistic device through a second feeding pump and a second flow controller. The pregel and crystallization reaction synergistic device is injected into the pregel and crystallization reaction synergistic device through the second feed port at a flow rate of 0.1 to 10 L / min, and the pregel is performed at 0 to 100 ° C for 1 to 3600 seconds; after the pregel reaction is completed, the ultrasonic generator is turned off, the microwave generator is turned on, the temperature of the reaction system is increased to 150 to 200 ° C, and the crystallization reaction is performed for 0.2 to 72 hours to form a mixed slurry; the obtained mixed slurry enters the solid-liquid separation device through the discharge port, and the liquid after separation is evaporated and concentrated for secondary crystallization and recycling, and the solid after separation is dried to obtain a multi-level porous nano ZSM-5 molecular sieve; Wherein, the molar ratio of the structure directing agent to the SiO2 in the silicon-containing solution is (0.001-1):1.

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